Vendor import of clang trunk r300422:vendor/clang/clang-trunk-r300422

https://llvm.org/svn/llvm-project/cfe/trunk@300422

91 files changed, 24265 insertions, 21330 deletions

diff --git a/lib/Driver/CMakeLists.txt b/lib/Driver/CMakeLists.txt
index 3ebd1c4f891e..43d6aa8f99b8 100644
--- a/lib/Driver/CMakeLists.txt
+++ b/lib/Driver/CMakeLists.txt
@@ -11,21 +11,54 @@ endif()
 add_clang_library(clangDriver
   Action.cpp
   Compilation.cpp
-  CrossWindowsToolChain.cpp
   Distro.cpp
   Driver.cpp
   DriverOptions.cpp
   Job.cpp
-  MinGWToolChain.cpp
   Multilib.cpp
-  MSVCToolChain.cpp
   Phases.cpp
   SanitizerArgs.cpp
   Tool.cpp
   ToolChain.cpp
-  ToolChains.cpp
-  Tools.cpp
+  ToolChains/Arch/AArch64.cpp
+  ToolChains/Arch/ARM.cpp
+  ToolChains/Arch/Mips.cpp
+  ToolChains/Arch/PPC.cpp
+  ToolChains/Arch/Sparc.cpp
+  ToolChains/Arch/SystemZ.cpp
+  ToolChains/Arch/X86.cpp
+  ToolChains/AMDGPU.cpp
+  ToolChains/AVR.cpp
+  ToolChains/Bitrig.cpp
+  ToolChains/Clang.cpp
+  ToolChains/CloudABI.cpp
+  ToolChains/CommonArgs.cpp
+  ToolChains/Contiki.cpp
+  ToolChains/CrossWindows.cpp
+  ToolChains/Cuda.cpp
+  ToolChains/Darwin.cpp
+  ToolChains/DragonFly.cpp
+  ToolChains/FreeBSD.cpp
+  ToolChains/Fuchsia.cpp
+  ToolChains/Gnu.cpp
+  ToolChains/Haiku.cpp
+  ToolChains/Hexagon.cpp
+  ToolChains/Linux.cpp
+  ToolChains/MipsLinux.cpp
+  ToolChains/MinGW.cpp
+  ToolChains/Minix.cpp
+  ToolChains/MSVC.cpp
+  ToolChains/Myriad.cpp
+  ToolChains/NaCl.cpp
+  ToolChains/NetBSD.cpp
+  ToolChains/OpenBSD.cpp
+  ToolChains/PS4CPU.cpp
+  ToolChains/Solaris.cpp
+  ToolChains/TCE.cpp
+  ToolChains/WebAssembly.cpp
+  ToolChains/XCore.cpp
   Types.cpp
+  XRayArgs.cpp
 
   DEPENDS
   ClangDriverOptions
diff --git a/lib/Driver/CrossWindowsToolChain.cpp b/lib/Driver/CrossWindowsToolChain.cpp
deleted file mode 100644
index 28036ea51cff..000000000000
--- a/lib/Driver/CrossWindowsToolChain.cpp
+++ /dev/null
@@ -1,125 +0,0 @@
-//===--- CrossWindowsToolChain.cpp - Cross Windows Tool Chain -------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#include "ToolChains.h"
-#include "clang/Driver/Driver.h"
-#include "clang/Driver/Options.h"
-#include "llvm/Option/ArgList.h"
-#include "llvm/Support/Path.h"
-
-using namespace clang::driver;
-using namespace clang::driver::toolchains;
-
-CrossWindowsToolChain::CrossWindowsToolChain(const Driver &D,
-                                             const llvm::Triple &T,
-                                             const llvm::opt::ArgList &Args)
-    : Generic_GCC(D, T, Args) {
-  if (GetCXXStdlibType(Args) == ToolChain::CST_Libstdcxx) {
-    const std::string &SysRoot = D.SysRoot;
-
-    // libstdc++ resides in /usr/lib, but depends on libgcc which is placed in
-    // /usr/lib/gcc.
-    getFilePaths().push_back(SysRoot + "/usr/lib");
-    getFilePaths().push_back(SysRoot + "/usr/lib/gcc");
-  }
-}
-
-bool CrossWindowsToolChain::IsUnwindTablesDefault() const {
-  // FIXME: all non-x86 targets need unwind tables, however, LLVM currently does
-  // not know how to emit them.
-  return getArch() == llvm::Triple::x86_64;
-}
-
-bool CrossWindowsToolChain::isPICDefault() const {
-  return getArch() == llvm::Triple::x86_64;
-}
-
-bool CrossWindowsToolChain::isPIEDefault() const {
-  return getArch() == llvm::Triple::x86_64;
-}
-
-bool CrossWindowsToolChain::isPICDefaultForced() const {
-  return getArch() == llvm::Triple::x86_64;
-}
-
-void CrossWindowsToolChain::
-AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                          llvm::opt::ArgStringList &CC1Args) const {
-  const Driver &D = getDriver();
-  const std::string &SysRoot = D.SysRoot;
-
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
-    return;
-
-  addSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/local/include");
-  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
-    SmallString<128> ResourceDir(D.ResourceDir);
-    llvm::sys::path::append(ResourceDir, "include");
-    addSystemInclude(DriverArgs, CC1Args, ResourceDir);
-  }
-  for (const auto &P : DriverArgs.getAllArgValues(options::OPT_isystem_after))
-    addSystemInclude(DriverArgs, CC1Args, P);
-  addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include");
-}
-
-void CrossWindowsToolChain::
-AddClangCXXStdlibIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                             llvm::opt::ArgStringList &CC1Args) const {
-  const llvm::Triple &Triple = getTriple();
-  const std::string &SysRoot = getDriver().SysRoot;
-
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
-      DriverArgs.hasArg(options::OPT_nostdincxx))
-    return;
-
-  switch (GetCXXStdlibType(DriverArgs)) {
-  case ToolChain::CST_Libcxx:
-    addSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include/c++/v1");
-    break;
-
-  case ToolChain::CST_Libstdcxx:
-    addSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include/c++");
-    addSystemInclude(DriverArgs, CC1Args,
-                     SysRoot + "/usr/include/c++/" + Triple.str());
-    addSystemInclude(DriverArgs, CC1Args,
-                     SysRoot + "/usr/include/c++/backwards");
-  }
-}
-
-void CrossWindowsToolChain::
-AddCXXStdlibLibArgs(const llvm::opt::ArgList &DriverArgs,
-                    llvm::opt::ArgStringList &CC1Args) const {
-  switch (GetCXXStdlibType(DriverArgs)) {
-  case ToolChain::CST_Libcxx:
-    CC1Args.push_back("-lc++");
-    break;
-  case ToolChain::CST_Libstdcxx:
-    CC1Args.push_back("-lstdc++");
-    CC1Args.push_back("-lmingw32");
-    CC1Args.push_back("-lmingwex");
-    CC1Args.push_back("-lgcc");
-    CC1Args.push_back("-lmoldname");
-    CC1Args.push_back("-lmingw32");
-    break;
-  }
-}
-
-clang::SanitizerMask CrossWindowsToolChain::getSupportedSanitizers() const {
-  SanitizerMask Res = ToolChain::getSupportedSanitizers();
-  Res |= SanitizerKind::Address;
-  return Res;
-}
-
-Tool *CrossWindowsToolChain::buildLinker() const {
-  return new tools::CrossWindows::Linker(*this);
-}
-
-Tool *CrossWindowsToolChain::buildAssembler() const {
-  return new tools::CrossWindows::Assembler(*this);
-}
diff --git a/lib/Driver/Driver.cpp b/lib/Driver/Driver.cpp
index 15f830d029eb..f36deff5d734 100644
--- a/lib/Driver/Driver.cpp
+++ b/lib/Driver/Driver.cpp
@@ -9,7 +9,36 @@
 
 #include "clang/Driver/Driver.h"
 #include "InputInfo.h"
-#include "ToolChains.h"
+#include "ToolChains/AMDGPU.h"
+#include "ToolChains/AVR.h"
+#include "ToolChains/Bitrig.h"
+#include "ToolChains/Clang.h"
+#include "ToolChains/CloudABI.h"
+#include "ToolChains/Contiki.h"
+#include "ToolChains/CrossWindows.h"
+#include "ToolChains/Cuda.h"
+#include "ToolChains/Darwin.h"
+#include "ToolChains/DragonFly.h"
+#include "ToolChains/FreeBSD.h"
+#include "ToolChains/Fuchsia.h"
+#include "ToolChains/Gnu.h"
+#include "ToolChains/Haiku.h"
+#include "ToolChains/Hexagon.h"
+#include "ToolChains/Lanai.h"
+#include "ToolChains/Linux.h"
+#include "ToolChains/MinGW.h"
+#include "ToolChains/Minix.h"
+#include "ToolChains/MipsLinux.h"
+#include "ToolChains/MSVC.h"
+#include "ToolChains/Myriad.h"
+#include "ToolChains/NaCl.h"
+#include "ToolChains/NetBSD.h"
+#include "ToolChains/OpenBSD.h"
+#include "ToolChains/PS4CPU.h"
+#include "ToolChains/Solaris.h"
+#include "ToolChains/TCE.h"
+#include "ToolChains/WebAssembly.h"
+#include "ToolChains/XCore.h"
 #include "clang/Basic/Version.h"
 #include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Config/config.h"
@@ -62,7 +91,7 @@ Driver::Driver(StringRef ClangExecutable, StringRef DefaultTargetTriple,
       CCCPrintBindings(false), CCPrintHeaders(false), CCLogDiagnostics(false),
       CCGenDiagnostics(false), DefaultTargetTriple(DefaultTargetTriple),
       CCCGenericGCCName(""), CheckInputsExist(true), CCCUsePCH(true),
-      SuppressMissingInputWarning(false) {
+      GenReproducer(false), SuppressMissingInputWarning(false) {
 
   // Provide a sane fallback if no VFS is specified.
   if (!this->VFS)
@@ -79,18 +108,13 @@ Driver::Driver(StringRef ClangExecutable, StringRef DefaultTargetTriple,
     llvm::sys::path::append(P, ClangResourceDir);
   } else {
     StringRef ClangLibdirSuffix(CLANG_LIBDIR_SUFFIX);
-    llvm::sys::path::append(P, "..", Twine("lib") + ClangLibdirSuffix, "clang",
+    P = llvm::sys::path::parent_path(Dir);
+    llvm::sys::path::append(P, Twine("lib") + ClangLibdirSuffix, "clang",
                             CLANG_VERSION_STRING);
   }
   ResourceDir = P.str();
 }
 
-Driver::~Driver() {
-  delete Opts;
-
-  llvm::DeleteContainerSeconds(ToolChains);
-}
-
 void Driver::ParseDriverMode(StringRef ProgramName,
                              ArrayRef<const char *> Args) {
   auto Default = ToolChain::getTargetAndModeFromProgramName(ProgramName);
@@ -214,9 +238,9 @@ phases::ID Driver::getFinalPhase(const DerivedArgList &DAL,
   return FinalPhase;
 }
 
-static Arg *MakeInputArg(DerivedArgList &Args, OptTable *Opts,
+static Arg *MakeInputArg(DerivedArgList &Args, OptTable &Opts,
                          StringRef Value) {
-  Arg *A = new Arg(Opts->getOption(options::OPT_INPUT), Value,
+  Arg *A = new Arg(Opts.getOption(options::OPT_INPUT), Value,
                    Args.getBaseArgs().MakeIndex(Value), Value.data());
   Args.AddSynthesizedArg(A);
   A->claim();
@@ -287,7 +311,7 @@ DerivedArgList *Driver::TranslateInputArgs(const InputArgList &Args) const {
     if (A->getOption().matches(options::OPT__DASH_DASH)) {
       A->claim();
       for (StringRef Val : A->getValues())
-        DAL->append(MakeInputArg(*DAL, Opts, Val));
+        DAL->append(MakeInputArg(*DAL, *Opts, Val));
       continue;
     }
 
@@ -479,12 +503,12 @@ void Driver::CreateOffloadingDeviceToolChains(Compilation &C,
                                                      : "nvptx-nvidia-cuda");
     // Use the CUDA and host triples as the key into the ToolChains map, because
     // the device toolchain we create depends on both.
-    ToolChain *&CudaTC = ToolChains[CudaTriple.str() + "/" + HostTriple.str()];
+    auto &CudaTC = ToolChains[CudaTriple.str() + "/" + HostTriple.str()];
     if (!CudaTC) {
-      CudaTC = new toolchains::CudaToolChain(*this, CudaTriple, *HostTC,
-                                             C.getInputArgs());
+      CudaTC = llvm::make_unique<toolchains::CudaToolChain>(
+          *this, CudaTriple, *HostTC, C.getInputArgs());
     }
-    C.addOffloadDeviceToolChain(CudaTC, Action::OFK_Cuda);
+    C.addOffloadDeviceToolChain(CudaTC.get(), Action::OFK_Cuda);
   }
 
   //
@@ -596,6 +620,9 @@ Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
     CCCGenericGCCName = A->getValue();
   CCCUsePCH =
       Args.hasFlag(options::OPT_ccc_pch_is_pch, options::OPT_ccc_pch_is_pth);
+  GenReproducer = Args.hasFlag(options::OPT_gen_reproducer,
+                               options::OPT_fno_crash_diagnostics,
+                               !!::getenv("FORCE_CLANG_DIAGNOSTICS_CRASH"));
   // FIXME: DefaultTargetTriple is used by the target-prefixed calls to as/ld
   // and getToolChain is const.
   if (IsCLMode()) {
@@ -1145,6 +1172,11 @@ bool Driver::HandleImmediateArgs(const Compilation &C) {
   if (C.getArgs().hasArg(options::OPT_v))
     TC.printVerboseInfo(llvm::errs());
 
+  if (C.getArgs().hasArg(options::OPT_print_resource_dir)) {
+    llvm::outs() << ResourceDir << '\n';
+    return false;
+  }
+
   if (C.getArgs().hasArg(options::OPT_print_search_dirs)) {
     llvm::outs() << "programs: =";
     bool separator = false;
@@ -1462,16 +1494,15 @@ void Driver::BuildInputs(const ToolChain &TC, DerivedArgList &Args,
                     ? types::TY_C
                     : types::TY_CXX;
 
-    arg_iterator it =
-        Args.filtered_begin(options::OPT__SLASH_TC, options::OPT__SLASH_TP);
-    const arg_iterator ie = Args.filtered_end();
-    Arg *Previous = *it++;
+    Arg *Previous = nullptr;
     bool ShowNote = false;
-    while (it != ie) {
-      Diag(clang::diag::warn_drv_overriding_flag_option)
-          << Previous->getSpelling() << (*it)->getSpelling();
-      Previous = *it++;
-      ShowNote = true;
+    for (Arg *A : Args.filtered(options::OPT__SLASH_TC, options::OPT__SLASH_TP)) {
+      if (Previous) {
+        Diag(clang::diag::warn_drv_overriding_flag_option)
+          << Previous->getSpelling() << A->getSpelling();
+        ShowNote = true;
+      }
+      Previous = A;
     }
     if (ShowNote)
       Diag(clang::diag::note_drv_t_option_is_global);
@@ -1561,14 +1592,14 @@ void Driver::BuildInputs(const ToolChain &TC, DerivedArgList &Args,
     } else if (A->getOption().matches(options::OPT__SLASH_Tc)) {
       StringRef Value = A->getValue();
       if (DiagnoseInputExistence(*this, Args, Value, types::TY_C)) {
-        Arg *InputArg = MakeInputArg(Args, Opts, A->getValue());
+        Arg *InputArg = MakeInputArg(Args, *Opts, A->getValue());
         Inputs.push_back(std::make_pair(types::TY_C, InputArg));
       }
       A->claim();
     } else if (A->getOption().matches(options::OPT__SLASH_Tp)) {
       StringRef Value = A->getValue();
       if (DiagnoseInputExistence(*this, Args, Value, types::TY_CXX)) {
-        Arg *InputArg = MakeInputArg(Args, Opts, A->getValue());
+        Arg *InputArg = MakeInputArg(Args, *Opts, A->getValue());
         Inputs.push_back(std::make_pair(types::TY_CXX, InputArg));
       }
       A->claim();
@@ -1589,12 +1620,20 @@ void Driver::BuildInputs(const ToolChain &TC, DerivedArgList &Args,
         Diag(clang::diag::err_drv_unknown_language) << A->getValue();
         InputType = types::TY_Object;
       }
+    } else if (A->getOption().getID() == options::OPT__SLASH_U) {
+      assert(A->getNumValues() == 1 && "The /U option has one value.");
+      StringRef Val = A->getValue(0);
+      if (Val.find_first_of("/\\") != StringRef::npos) {
+        // Warn about e.g. "/Users/me/myfile.c".
+        Diag(diag::warn_slash_u_filename) << Val;
+        Diag(diag::note_use_dashdash);
+      }
     }
   }
   if (CCCIsCPP() && Inputs.empty()) {
     // If called as standalone preprocessor, stdin is processed
     // if no other input is present.
-    Arg *A = MakeInputArg(Args, Opts, "-");
+    Arg *A = MakeInputArg(Args, *Opts, "-");
     Inputs.push_back(std::make_pair(types::TY_C, A));
   }
 }
@@ -2351,8 +2390,12 @@ void Driver::BuildActions(Compilation &C, DerivedArgList &Args,
   Arg *FinalPhaseArg;
   phases::ID FinalPhase = getFinalPhase(Args, &FinalPhaseArg);
 
-  if (FinalPhase == phases::Link && Args.hasArg(options::OPT_emit_llvm)) {
-    Diag(clang::diag::err_drv_emit_llvm_link);
+  if (FinalPhase == phases::Link) {
+    if (Args.hasArg(options::OPT_emit_llvm))
+      Diag(clang::diag::err_drv_emit_llvm_link);
+    if (IsCLMode() && LTOMode != LTOK_None &&
+        !Args.getLastArgValue(options::OPT_fuse_ld_EQ).equals_lower("lld"))
+      Diag(clang::diag::err_drv_lto_without_lld);
   }
 
   // Reject -Z* at the top level, these options should never have been exposed
@@ -2497,7 +2540,7 @@ void Driver::BuildActions(Compilation &C, DerivedArgList &Args,
         const types::ID HeaderType = lookupHeaderTypeForSourceType(InputType);
         llvm::SmallVector<phases::ID, phases::MaxNumberOfPhases> PCHPL;
         types::getCompilationPhases(HeaderType, PCHPL);
-        Arg *PchInputArg = MakeInputArg(Args, Opts, YcArg->getValue());
+        Arg *PchInputArg = MakeInputArg(Args, *Opts, YcArg->getValue());
 
         // Build the pipeline for the pch file.
         Action *ClangClPch =
@@ -3186,7 +3229,8 @@ InputInfo Driver::BuildJobsForActionNoCache(
   const JobAction *JA = cast<JobAction>(A);
   ActionList CollapsedOffloadActions;
 
-  ToolSelector TS(JA, *TC, C, isSaveTempsEnabled(), embedBitcodeInObject());
+  ToolSelector TS(JA, *TC, C, isSaveTempsEnabled(),
+                  embedBitcodeInObject() && !isUsingLTO());
   const Tool *T = TS.getTool(Inputs, CollapsedOffloadActions);
 
   if (!T)
@@ -3657,125 +3701,130 @@ std::string Driver::GetClPchPath(Compilation &C, StringRef BaseName) const {
 const ToolChain &Driver::getToolChain(const ArgList &Args,
                                       const llvm::Triple &Target) const {
 
-  ToolChain *&TC = ToolChains[Target.str()];
+  auto &TC = ToolChains[Target.str()];
   if (!TC) {
     switch (Target.getOS()) {
     case llvm::Triple::Haiku:
-      TC = new toolchains::Haiku(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::Haiku>(*this, Target, Args);
       break;
     case llvm::Triple::CloudABI:
-      TC = new toolchains::CloudABI(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::CloudABI>(*this, Target, Args);
       break;
     case llvm::Triple::Darwin:
     case llvm::Triple::MacOSX:
     case llvm::Triple::IOS:
     case llvm::Triple::TvOS:
     case llvm::Triple::WatchOS:
-      TC = new toolchains::DarwinClang(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::DarwinClang>(*this, Target, Args);
       break;
     case llvm::Triple::DragonFly:
-      TC = new toolchains::DragonFly(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::DragonFly>(*this, Target, Args);
       break;
     case llvm::Triple::OpenBSD:
-      TC = new toolchains::OpenBSD(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::OpenBSD>(*this, Target, Args);
       break;
     case llvm::Triple::Bitrig:
-      TC = new toolchains::Bitrig(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::Bitrig>(*this, Target, Args);
       break;
     case llvm::Triple::NetBSD:
-      TC = new toolchains::NetBSD(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::NetBSD>(*this, Target, Args);
       break;
     case llvm::Triple::FreeBSD:
-      TC = new toolchains::FreeBSD(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::FreeBSD>(*this, Target, Args);
       break;
     case llvm::Triple::Minix:
-      TC = new toolchains::Minix(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::Minix>(*this, Target, Args);
       break;
     case llvm::Triple::Linux:
     case llvm::Triple::ELFIAMCU:
       if (Target.getArch() == llvm::Triple::hexagon)
-        TC = new toolchains::HexagonToolChain(*this, Target, Args);
+        TC = llvm::make_unique<toolchains::HexagonToolChain>(*this, Target,
+                                                             Args);
       else if ((Target.getVendor() == llvm::Triple::MipsTechnologies) &&
                !Target.hasEnvironment())
-        TC = new toolchains::MipsLLVMToolChain(*this, Target, Args);
+        TC = llvm::make_unique<toolchains::MipsLLVMToolChain>(*this, Target,
+                                                              Args);
       else
-        TC = new toolchains::Linux(*this, Target, Args);
+        TC = llvm::make_unique<toolchains::Linux>(*this, Target, Args);
       break;
     case llvm::Triple::NaCl:
-      TC = new toolchains::NaClToolChain(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::NaClToolChain>(*this, Target, Args);
       break;
     case llvm::Triple::Fuchsia:
-      TC = new toolchains::Fuchsia(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::Fuchsia>(*this, Target, Args);
       break;
     case llvm::Triple::Solaris:
-      TC = new toolchains::Solaris(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::Solaris>(*this, Target, Args);
       break;
     case llvm::Triple::AMDHSA:
-      TC = new toolchains::AMDGPUToolChain(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::AMDGPUToolChain>(*this, Target, Args);
       break;
     case llvm::Triple::Win32:
       switch (Target.getEnvironment()) {
       default:
         if (Target.isOSBinFormatELF())
-          TC = new toolchains::Generic_ELF(*this, Target, Args);
+          TC = llvm::make_unique<toolchains::Generic_ELF>(*this, Target, Args);
         else if (Target.isOSBinFormatMachO())
-          TC = new toolchains::MachO(*this, Target, Args);
+          TC = llvm::make_unique<toolchains::MachO>(*this, Target, Args);
         else
-          TC = new toolchains::Generic_GCC(*this, Target, Args);
+          TC = llvm::make_unique<toolchains::Generic_GCC>(*this, Target, Args);
         break;
       case llvm::Triple::GNU:
-        TC = new toolchains::MinGW(*this, Target, Args);
+        TC = llvm::make_unique<toolchains::MinGW>(*this, Target, Args);
         break;
       case llvm::Triple::Itanium:
-        TC = new toolchains::CrossWindowsToolChain(*this, Target, Args);
+        TC = llvm::make_unique<toolchains::CrossWindowsToolChain>(*this, Target,
+                                                                  Args);
         break;
       case llvm::Triple::MSVC:
       case llvm::Triple::UnknownEnvironment:
-        TC = new toolchains::MSVCToolChain(*this, Target, Args);
+        TC = llvm::make_unique<toolchains::MSVCToolChain>(*this, Target, Args);
         break;
       }
       break;
     case llvm::Triple::PS4:
-      TC = new toolchains::PS4CPU(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::PS4CPU>(*this, Target, Args);
       break;
     case llvm::Triple::Contiki:
-      TC = new toolchains::Contiki(*this, Target, Args);
+      TC = llvm::make_unique<toolchains::Contiki>(*this, Target, Args);
       break;
     default:
       // Of these targets, Hexagon is the only one that might have
       // an OS of Linux, in which case it got handled above already.
       switch (Target.getArch()) {
       case llvm::Triple::tce:
-        TC = new toolchains::TCEToolChain(*this, Target, Args);
+        TC = llvm::make_unique<toolchains::TCEToolChain>(*this, Target, Args);
         break;
       case llvm::Triple::tcele:
-        TC = new toolchains::TCELEToolChain(*this, Target, Args);
+        TC = llvm::make_unique<toolchains::TCELEToolChain>(*this, Target, Args);
         break;
       case llvm::Triple::hexagon:
-        TC = new toolchains::HexagonToolChain(*this, Target, Args);
+        TC = llvm::make_unique<toolchains::HexagonToolChain>(*this, Target,
+                                                             Args);
         break;
       case llvm::Triple::lanai:
-        TC = new toolchains::LanaiToolChain(*this, Target, Args);
+        TC = llvm::make_unique<toolchains::LanaiToolChain>(*this, Target, Args);
         break;
       case llvm::Triple::xcore:
-        TC = new toolchains::XCoreToolChain(*this, Target, Args);
+        TC = llvm::make_unique<toolchains::XCoreToolChain>(*this, Target, Args);
         break;
       case llvm::Triple::wasm32:
       case llvm::Triple::wasm64:
-        TC = new toolchains::WebAssembly(*this, Target, Args);
+        TC = llvm::make_unique<toolchains::WebAssembly>(*this, Target, Args);
         break;
       case llvm::Triple::avr:
-        TC = new toolchains::AVRToolChain(*this, Target, Args);
+        TC = llvm::make_unique<toolchains::AVRToolChain>(*this, Target, Args);
         break;
       default:
         if (Target.getVendor() == llvm::Triple::Myriad)
-          TC = new toolchains::MyriadToolChain(*this, Target, Args);
+          TC = llvm::make_unique<toolchains::MyriadToolChain>(*this, Target,
+                                                              Args);
         else if (Target.isOSBinFormatELF())
-          TC = new toolchains::Generic_ELF(*this, Target, Args);
+          TC = llvm::make_unique<toolchains::Generic_ELF>(*this, Target, Args);
         else if (Target.isOSBinFormatMachO())
-          TC = new toolchains::MachO(*this, Target, Args);
+          TC = llvm::make_unique<toolchains::MachO>(*this, Target, Args);
         else
-          TC = new toolchains::Generic_GCC(*this, Target, Args);
+          TC = llvm::make_unique<toolchains::Generic_GCC>(*this, Target, Args);
       }
     }
   }
diff --git a/lib/Driver/DriverOptions.cpp b/lib/Driver/DriverOptions.cpp
index 8d5332b5cc24..6a7410901d25 100644
--- a/lib/Driver/DriverOptions.cpp
+++ b/lib/Driver/DriverOptions.cpp
@@ -39,6 +39,6 @@ public:
 
 }
 
-OptTable *clang::driver::createDriverOptTable() {
-  return new DriverOptTable();
+std::unique_ptr<OptTable> clang::driver::createDriverOptTable() {
+  return llvm::make_unique<DriverOptTable>();
 }
diff --git a/lib/Driver/Job.cpp b/lib/Driver/Job.cpp
index 9fd8808af302..7a4d055159ec 100644
--- a/lib/Driver/Job.cpp
+++ b/lib/Driver/Job.cpp
@@ -301,19 +301,33 @@ void Command::setResponseFile(const char *FileName) {
   ResponseFileFlag += FileName;
 }
 
+void Command::setEnvironment(llvm::ArrayRef<const char *> NewEnvironment) {
+  Environment.reserve(NewEnvironment.size() + 1);
+  Environment.assign(NewEnvironment.begin(), NewEnvironment.end());
+  Environment.push_back(nullptr);
+}
+
 int Command::Execute(const StringRef **Redirects, std::string *ErrMsg,
                      bool *ExecutionFailed) const {
   SmallVector<const char*, 128> Argv;
 
+  const char **Envp;
+  if (Environment.empty()) {
+    Envp = nullptr;
+  } else {
+    assert(Environment.back() == nullptr &&
+           "Environment vector should be null-terminated by now");
+    Envp = const_cast<const char **>(Environment.data());
+  }
+
   if (ResponseFile == nullptr) {
     Argv.push_back(Executable);
     Argv.append(Arguments.begin(), Arguments.end());
     Argv.push_back(nullptr);
 
-    return llvm::sys::ExecuteAndWait(Executable, Argv.data(), /*env*/ nullptr,
-                                     Redirects, /*secondsToWait*/ 0,
-                                     /*memoryLimit*/ 0, ErrMsg,
-                                     ExecutionFailed);
+    return llvm::sys::ExecuteAndWait(
+        Executable, Argv.data(), Envp, Redirects, /*secondsToWait*/ 0,
+        /*memoryLimit*/ 0, ErrMsg, ExecutionFailed);
   }
 
   // We need to put arguments in a response file (command is too large)
@@ -337,8 +351,8 @@ int Command::Execute(const StringRef **Redirects, std::string *ErrMsg,
     return -1;
   }
 
-  return llvm::sys::ExecuteAndWait(Executable, Argv.data(), /*env*/ nullptr,
-                                   Redirects, /*secondsToWait*/ 0,
+  return llvm::sys::ExecuteAndWait(Executable, Argv.data(), Envp, Redirects,
+                                   /*secondsToWait*/ 0,
                                    /*memoryLimit*/ 0, ErrMsg, ExecutionFailed);
 }
 
diff --git a/lib/Driver/MSVCToolChain.cpp b/lib/Driver/MSVCToolChain.cpp
deleted file mode 100644
index 17fd6ac6f714..000000000000
--- a/lib/Driver/MSVCToolChain.cpp
+++ /dev/null
@@ -1,892 +0,0 @@
-//===--- ToolChains.cpp - ToolChain Implementations -----------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#include "ToolChains.h"
-#include "Tools.h"
-#include "clang/Basic/CharInfo.h"
-#include "clang/Basic/Version.h"
-#include "clang/Driver/Compilation.h"
-#include "clang/Driver/Driver.h"
-#include "clang/Driver/DriverDiagnostic.h"
-#include "clang/Driver/Options.h"
-#include "llvm/ADT/StringExtras.h"
-#include "llvm/ADT/StringSwitch.h"
-#include "llvm/Config/llvm-config.h"
-#include "llvm/Option/Arg.h"
-#include "llvm/Option/ArgList.h"
-#include "llvm/Support/ConvertUTF.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/FileSystem.h"
-#include "llvm/Support/Path.h"
-#include "llvm/Support/Process.h"
-#include <cstdio>
-
-// Include the necessary headers to interface with the Windows registry and
-// environment.
-#if defined(LLVM_ON_WIN32)
-#define USE_WIN32
-#endif
-
-#ifdef USE_WIN32
-  #define WIN32_LEAN_AND_MEAN
-  #define NOGDI
-  #ifndef NOMINMAX
-    #define NOMINMAX
-  #endif
-  #include <windows.h>
-#endif
-
-using namespace clang::driver;
-using namespace clang::driver::toolchains;
-using namespace clang;
-using namespace llvm::opt;
-
-MSVCToolChain::MSVCToolChain(const Driver &D, const llvm::Triple &Triple,
-                             const ArgList &Args)
-    : ToolChain(D, Triple, Args), CudaInstallation(D, Triple, Args) {
-  getProgramPaths().push_back(getDriver().getInstalledDir());
-  if (getDriver().getInstalledDir() != getDriver().Dir)
-    getProgramPaths().push_back(getDriver().Dir);
-}
-
-Tool *MSVCToolChain::buildLinker() const {
-  return new tools::visualstudio::Linker(*this);
-}
-
-Tool *MSVCToolChain::buildAssembler() const {
-  if (getTriple().isOSBinFormatMachO())
-    return new tools::darwin::Assembler(*this);
-  getDriver().Diag(clang::diag::err_no_external_assembler);
-  return nullptr;
-}
-
-bool MSVCToolChain::IsIntegratedAssemblerDefault() const {
-  return true;
-}
-
-bool MSVCToolChain::IsUnwindTablesDefault() const {
-  // Emit unwind tables by default on Win64. All non-x86_32 Windows platforms
-  // such as ARM and PPC actually require unwind tables, but LLVM doesn't know
-  // how to generate them yet.
-
-  // Don't emit unwind tables by default for MachO targets.
-  if (getTriple().isOSBinFormatMachO())
-    return false;
-
-  return getArch() == llvm::Triple::x86_64;
-}
-
-bool MSVCToolChain::isPICDefault() const {
-  return getArch() == llvm::Triple::x86_64;
-}
-
-bool MSVCToolChain::isPIEDefault() const {
-  return false;
-}
-
-bool MSVCToolChain::isPICDefaultForced() const {
-  return getArch() == llvm::Triple::x86_64;
-}
-
-void MSVCToolChain::AddCudaIncludeArgs(const ArgList &DriverArgs,
-                                       ArgStringList &CC1Args) const {
-  CudaInstallation.AddCudaIncludeArgs(DriverArgs, CC1Args);
-}
-
-void MSVCToolChain::printVerboseInfo(raw_ostream &OS) const {
-  CudaInstallation.print(OS);
-}
-
-#ifdef USE_WIN32
-static bool readFullStringValue(HKEY hkey, const char *valueName,
-                                std::string &value) {
-  std::wstring WideValueName;
-  if (!llvm::ConvertUTF8toWide(valueName, WideValueName))
-    return false;
-
-  DWORD result = 0;
-  DWORD valueSize = 0;
-  DWORD type = 0;
-  // First just query for the required size.
-  result = RegQueryValueExW(hkey, WideValueName.c_str(), NULL, &type, NULL,
-                            &valueSize);
-  if (result != ERROR_SUCCESS || type != REG_SZ || !valueSize)
-    return false;
-  std::vector<BYTE> buffer(valueSize);
-  result = RegQueryValueExW(hkey, WideValueName.c_str(), NULL, NULL, &buffer[0],
-                            &valueSize);
-  if (result == ERROR_SUCCESS) {
-    std::wstring WideValue(reinterpret_cast<const wchar_t *>(buffer.data()),
-                           valueSize / sizeof(wchar_t));
-    if (valueSize && WideValue.back() == L'\0') {
-      WideValue.pop_back();
-    }
-    // The destination buffer must be empty as an invariant of the conversion
-    // function; but this function is sometimes called in a loop that passes in
-    // the same buffer, however. Simply clear it out so we can overwrite it.
-    value.clear();
-    return llvm::convertWideToUTF8(WideValue, value);
-  }
-  return false;
-}
-#endif
-
-/// \brief Read registry string.
-/// This also supports a means to look for high-versioned keys by use
-/// of a $VERSION placeholder in the key path.
-/// $VERSION in the key path is a placeholder for the version number,
-/// causing the highest value path to be searched for and used.
-/// I.e. "SOFTWARE\\Microsoft\\VisualStudio\\$VERSION".
-/// There can be additional characters in the component.  Only the numeric
-/// characters are compared.  This function only searches HKLM.
-static bool getSystemRegistryString(const char *keyPath, const char *valueName,
-                                    std::string &value, std::string *phValue) {
-#ifndef USE_WIN32
-  return false;
-#else
-  HKEY hRootKey = HKEY_LOCAL_MACHINE;
-  HKEY hKey = NULL;
-  long lResult;
-  bool returnValue = false;
-
-  const char *placeHolder = strstr(keyPath, "$VERSION");
-  std::string bestName;
-  // If we have a $VERSION placeholder, do the highest-version search.
-  if (placeHolder) {
-    const char *keyEnd = placeHolder - 1;
-    const char *nextKey = placeHolder;
-    // Find end of previous key.
-    while ((keyEnd > keyPath) && (*keyEnd != '\\'))
-      keyEnd--;
-    // Find end of key containing $VERSION.
-    while (*nextKey && (*nextKey != '\\'))
-      nextKey++;
-    size_t partialKeyLength = keyEnd - keyPath;
-    char partialKey[256];
-    if (partialKeyLength >= sizeof(partialKey))
-      partialKeyLength = sizeof(partialKey) - 1;
-    strncpy(partialKey, keyPath, partialKeyLength);
-    partialKey[partialKeyLength] = '\0';
-    HKEY hTopKey = NULL;
-    lResult = RegOpenKeyExA(hRootKey, partialKey, 0, KEY_READ | KEY_WOW64_32KEY,
-                            &hTopKey);
-    if (lResult == ERROR_SUCCESS) {
-      char keyName[256];
-      double bestValue = 0.0;
-      DWORD index, size = sizeof(keyName) - 1;
-      for (index = 0; RegEnumKeyExA(hTopKey, index, keyName, &size, NULL, NULL,
-                                    NULL, NULL) == ERROR_SUCCESS;
-           index++) {
-        const char *sp = keyName;
-        while (*sp && !isDigit(*sp))
-          sp++;
-        if (!*sp)
-          continue;
-        const char *ep = sp + 1;
-        while (*ep && (isDigit(*ep) || (*ep == '.')))
-          ep++;
-        char numBuf[32];
-        strncpy(numBuf, sp, sizeof(numBuf) - 1);
-        numBuf[sizeof(numBuf) - 1] = '\0';
-        double dvalue = strtod(numBuf, NULL);
-        if (dvalue > bestValue) {
-          // Test that InstallDir is indeed there before keeping this index.
-          // Open the chosen key path remainder.
-          bestName = keyName;
-          // Append rest of key.
-          bestName.append(nextKey);
-          lResult = RegOpenKeyExA(hTopKey, bestName.c_str(), 0,
-                                  KEY_READ | KEY_WOW64_32KEY, &hKey);
-          if (lResult == ERROR_SUCCESS) {
-            if (readFullStringValue(hKey, valueName, value)) {
-              bestValue = dvalue;
-              if (phValue)
-                *phValue = bestName;
-              returnValue = true;
-            }
-            RegCloseKey(hKey);
-          }
-        }
-        size = sizeof(keyName) - 1;
-      }
-      RegCloseKey(hTopKey);
-    }
-  } else {
-    lResult =
-        RegOpenKeyExA(hRootKey, keyPath, 0, KEY_READ | KEY_WOW64_32KEY, &hKey);
-    if (lResult == ERROR_SUCCESS) {
-      if (readFullStringValue(hKey, valueName, value))
-        returnValue = true;
-      if (phValue)
-        phValue->clear();
-      RegCloseKey(hKey);
-    }
-  }
-  return returnValue;
-#endif // USE_WIN32
-}
-
-// Convert LLVM's ArchType
-// to the corresponding name of Windows SDK libraries subfolder
-static StringRef getWindowsSDKArch(llvm::Triple::ArchType Arch) {
-  switch (Arch) {
-  case llvm::Triple::x86:
-    return "x86";
-  case llvm::Triple::x86_64:
-    return "x64";
-  case llvm::Triple::arm:
-    return "arm";
-  default:
-    return "";
-  }
-}
-
-// Find the most recent version of Universal CRT or Windows 10 SDK.
-// vcvarsqueryregistry.bat from Visual Studio 2015 sorts entries in the include
-// directory by name and uses the last one of the list.
-// So we compare entry names lexicographically to find the greatest one.
-static bool getWindows10SDKVersion(const std::string &SDKPath,
-                                   std::string &SDKVersion) {
-  SDKVersion.clear();
-
-  std::error_code EC;
-  llvm::SmallString<128> IncludePath(SDKPath);
-  llvm::sys::path::append(IncludePath, "Include");
-  for (llvm::sys::fs::directory_iterator DirIt(IncludePath, EC), DirEnd;
-       DirIt != DirEnd && !EC; DirIt.increment(EC)) {
-    if (!llvm::sys::fs::is_directory(DirIt->path()))
-      continue;
-    StringRef CandidateName = llvm::sys::path::filename(DirIt->path());
-    // If WDK is installed, there could be subfolders like "wdf" in the
-    // "Include" directory.
-    // Allow only directories which names start with "10.".
-    if (!CandidateName.startswith("10."))
-      continue;
-    if (CandidateName > SDKVersion)
-      SDKVersion = CandidateName;
-  }
-
-  return !SDKVersion.empty();
-}
-
-/// \brief Get Windows SDK installation directory.
-bool MSVCToolChain::getWindowsSDKDir(std::string &Path, int &Major,
-                                     std::string &WindowsSDKIncludeVersion,
-                                     std::string &WindowsSDKLibVersion) const {
-  std::string RegistrySDKVersion;
-  // Try the Windows registry.
-  if (!getSystemRegistryString(
-          "SOFTWARE\\Microsoft\\Microsoft SDKs\\Windows\\$VERSION",
-          "InstallationFolder", Path, &RegistrySDKVersion))
-    return false;
-  if (Path.empty() || RegistrySDKVersion.empty())
-    return false;
-
-  WindowsSDKIncludeVersion.clear();
-  WindowsSDKLibVersion.clear();
-  Major = 0;
-  std::sscanf(RegistrySDKVersion.c_str(), "v%d.", &Major);
-  if (Major <= 7)
-    return true;
-  if (Major == 8) {
-    // Windows SDK 8.x installs libraries in a folder whose names depend on the
-    // version of the OS you're targeting.  By default choose the newest, which
-    // usually corresponds to the version of the OS you've installed the SDK on.
-    const char *Tests[] = {"winv6.3", "win8", "win7"};
-    for (const char *Test : Tests) {
-      llvm::SmallString<128> TestPath(Path);
-      llvm::sys::path::append(TestPath, "Lib", Test);
-      if (llvm::sys::fs::exists(TestPath.c_str())) {
-        WindowsSDKLibVersion = Test;
-        break;
-      }
-    }
-    return !WindowsSDKLibVersion.empty();
-  }
-  if (Major == 10) {
-    if (!getWindows10SDKVersion(Path, WindowsSDKIncludeVersion))
-      return false;
-    WindowsSDKLibVersion = WindowsSDKIncludeVersion;
-    return true;
-  }
-  // Unsupported SDK version
-  return false;
-}
-
-// Gets the library path required to link against the Windows SDK.
-bool MSVCToolChain::getWindowsSDKLibraryPath(std::string &path) const {
-  std::string sdkPath;
-  int sdkMajor = 0;
-  std::string windowsSDKIncludeVersion;
-  std::string windowsSDKLibVersion;
-
-  path.clear();
-  if (!getWindowsSDKDir(sdkPath, sdkMajor, windowsSDKIncludeVersion,
-                        windowsSDKLibVersion))
-    return false;
-
-  llvm::SmallString<128> libPath(sdkPath);
-  llvm::sys::path::append(libPath, "Lib");
-  if (sdkMajor <= 7) {
-    switch (getArch()) {
-    // In Windows SDK 7.x, x86 libraries are directly in the Lib folder.
-    case llvm::Triple::x86:
-      break;
-    case llvm::Triple::x86_64:
-      llvm::sys::path::append(libPath, "x64");
-      break;
-    case llvm::Triple::arm:
-      // It is not necessary to link against Windows SDK 7.x when targeting ARM.
-      return false;
-    default:
-      return false;
-    }
-  } else {
-    const StringRef archName = getWindowsSDKArch(getArch());
-    if (archName.empty())
-      return false;
-    llvm::sys::path::append(libPath, windowsSDKLibVersion, "um", archName);
-  }
-
-  path = libPath.str();
-  return true;
-}
-
-// Check if the Include path of a specified version of Visual Studio contains
-// specific header files. If not, they are probably shipped with Universal CRT.
-bool clang::driver::toolchains::MSVCToolChain::useUniversalCRT(
-    std::string &VisualStudioDir) const {
-  llvm::SmallString<128> TestPath(VisualStudioDir);
-  llvm::sys::path::append(TestPath, "VC\\include\\stdlib.h");
-
-  return !llvm::sys::fs::exists(TestPath);
-}
-
-bool MSVCToolChain::getUniversalCRTSdkDir(std::string &Path,
-                                          std::string &UCRTVersion) const {
-  // vcvarsqueryregistry.bat for Visual Studio 2015 queries the registry
-  // for the specific key "KitsRoot10". So do we.
-  if (!getSystemRegistryString(
-          "SOFTWARE\\Microsoft\\Windows Kits\\Installed Roots", "KitsRoot10",
-          Path, nullptr))
-    return false;
-
-  return getWindows10SDKVersion(Path, UCRTVersion);
-}
-
-bool MSVCToolChain::getUniversalCRTLibraryPath(std::string &Path) const {
-  std::string UniversalCRTSdkPath;
-  std::string UCRTVersion;
-
-  Path.clear();
-  if (!getUniversalCRTSdkDir(UniversalCRTSdkPath, UCRTVersion))
-    return false;
-
-  StringRef ArchName = getWindowsSDKArch(getArch());
-  if (ArchName.empty())
-    return false;
-
-  llvm::SmallString<128> LibPath(UniversalCRTSdkPath);
-  llvm::sys::path::append(LibPath, "Lib", UCRTVersion, "ucrt", ArchName);
-
-  Path = LibPath.str();
-  return true;
-}
-
-// Get the location to use for Visual Studio binaries.  The location priority
-// is: %VCINSTALLDIR% > %PATH% > newest copy of Visual Studio installed on
-// system (as reported by the registry).
-bool MSVCToolChain::getVisualStudioBinariesFolder(const char *clangProgramPath,
-                                                  std::string &path) const {
-  path.clear();
-
-  SmallString<128> BinDir;
-
-  // First check the environment variables that vsvars32.bat sets.
-  llvm::Optional<std::string> VcInstallDir =
-      llvm::sys::Process::GetEnv("VCINSTALLDIR");
-  if (VcInstallDir.hasValue()) {
-    BinDir = VcInstallDir.getValue();
-    llvm::sys::path::append(BinDir, "bin");
-  } else {
-    // Next walk the PATH, trying to find a cl.exe in the path.  If we find one,
-    // use that.  However, make sure it's not clang's cl.exe.
-    llvm::Optional<std::string> OptPath = llvm::sys::Process::GetEnv("PATH");
-    if (OptPath.hasValue()) {
-      const char EnvPathSeparatorStr[] = {llvm::sys::EnvPathSeparator, '\0'};
-      SmallVector<StringRef, 8> PathSegments;
-      llvm::SplitString(OptPath.getValue(), PathSegments, EnvPathSeparatorStr);
-
-      for (StringRef PathSegment : PathSegments) {
-        if (PathSegment.empty())
-          continue;
-
-        SmallString<128> FilePath(PathSegment);
-        llvm::sys::path::append(FilePath, "cl.exe");
-        // Checking if cl.exe exists is a small optimization over calling
-        // can_execute, which really only checks for existence but will also do
-        // extra checks for cl.exe.exe.  These add up when walking a long path.
-        if (llvm::sys::fs::exists(FilePath.c_str()) &&
-            !llvm::sys::fs::equivalent(FilePath.c_str(), clangProgramPath)) {
-          // If we found it on the PATH, use it exactly as is with no
-          // modifications.
-          path = PathSegment;
-          return true;
-        }
-      }
-    }
-
-    std::string installDir;
-    // With no VCINSTALLDIR and nothing on the PATH, if we can't find it in the
-    // registry then we have no choice but to fail.
-    if (!getVisualStudioInstallDir(installDir))
-      return false;
-
-    // Regardless of what binary we're ultimately trying to find, we make sure
-    // that this is a Visual Studio directory by checking for cl.exe.  We use
-    // cl.exe instead of other binaries like link.exe because programs such as
-    // GnuWin32 also have a utility called link.exe, so cl.exe is the least
-    // ambiguous.
-    BinDir = installDir;
-    llvm::sys::path::append(BinDir, "VC", "bin");
-    SmallString<128> ClPath(BinDir);
-    llvm::sys::path::append(ClPath, "cl.exe");
-
-    if (!llvm::sys::fs::can_execute(ClPath.c_str()))
-      return false;
-  }
-
-  if (BinDir.empty())
-    return false;
-
-  switch (getArch()) {
-  case llvm::Triple::x86:
-    break;
-  case llvm::Triple::x86_64:
-    llvm::sys::path::append(BinDir, "amd64");
-    break;
-  case llvm::Triple::arm:
-    llvm::sys::path::append(BinDir, "arm");
-    break;
-  default:
-    // Whatever this is, Visual Studio doesn't have a toolchain for it.
-    return false;
-  }
-  path = BinDir.str();
-  return true;
-}
-
-VersionTuple MSVCToolChain::getMSVCVersionFromTriple() const {
-  unsigned Major, Minor, Micro;
-  getTriple().getEnvironmentVersion(Major, Minor, Micro);
-  if (Major || Minor || Micro)
-    return VersionTuple(Major, Minor, Micro);
-  return VersionTuple();
-}
-
-VersionTuple MSVCToolChain::getMSVCVersionFromExe() const {
-  VersionTuple Version;
-#ifdef USE_WIN32
-  std::string BinPath;
-  if (!getVisualStudioBinariesFolder("", BinPath))
-    return Version;
-  SmallString<128> ClExe(BinPath);
-  llvm::sys::path::append(ClExe, "cl.exe");
-
-  std::wstring ClExeWide;
-  if (!llvm::ConvertUTF8toWide(ClExe.c_str(), ClExeWide))
-    return Version;
-
-  const DWORD VersionSize = ::GetFileVersionInfoSizeW(ClExeWide.c_str(),
-                                                      nullptr);
-  if (VersionSize == 0)
-    return Version;
-
-  SmallVector<uint8_t, 4 * 1024> VersionBlock(VersionSize);
-  if (!::GetFileVersionInfoW(ClExeWide.c_str(), 0, VersionSize,
-                             VersionBlock.data()))
-    return Version;
-
-  VS_FIXEDFILEINFO *FileInfo = nullptr;
-  UINT FileInfoSize = 0;
-  if (!::VerQueryValueW(VersionBlock.data(), L"\\",
-                        reinterpret_cast<LPVOID *>(&FileInfo), &FileInfoSize) ||
-      FileInfoSize < sizeof(*FileInfo))
-    return Version;
-
-  const unsigned Major = (FileInfo->dwFileVersionMS >> 16) & 0xFFFF;
-  const unsigned Minor = (FileInfo->dwFileVersionMS      ) & 0xFFFF;
-  const unsigned Micro = (FileInfo->dwFileVersionLS >> 16) & 0xFFFF;
-
-  Version = VersionTuple(Major, Minor, Micro);
-#endif
-  return Version;
-}
-
-// Get Visual Studio installation directory.
-bool MSVCToolChain::getVisualStudioInstallDir(std::string &path) const {
-  // First check the environment variables that vsvars32.bat sets.
-  if (llvm::Optional<std::string> VcInstallDir =
-          llvm::sys::Process::GetEnv("VCINSTALLDIR")) {
-    path = std::move(*VcInstallDir);
-    path = path.substr(0, path.find("\\VC"));
-    return true;
-  }
-
-  std::string vsIDEInstallDir;
-  std::string vsExpressIDEInstallDir;
-  // Then try the windows registry.
-  bool hasVCDir =
-      getSystemRegistryString("SOFTWARE\\Microsoft\\VisualStudio\\$VERSION",
-                              "InstallDir", vsIDEInstallDir, nullptr);
-  if (hasVCDir && !vsIDEInstallDir.empty()) {
-    path = vsIDEInstallDir.substr(0, vsIDEInstallDir.find("\\Common7\\IDE"));
-    return true;
-  }
-
-  bool hasVCExpressDir =
-      getSystemRegistryString("SOFTWARE\\Microsoft\\VCExpress\\$VERSION",
-                              "InstallDir", vsExpressIDEInstallDir, nullptr);
-  if (hasVCExpressDir && !vsExpressIDEInstallDir.empty()) {
-    path = vsExpressIDEInstallDir.substr(
-        0, vsIDEInstallDir.find("\\Common7\\IDE"));
-    return true;
-  }
-
-  // Try the environment.
-  std::string vcomntools;
-  if (llvm::Optional<std::string> vs120comntools =
-          llvm::sys::Process::GetEnv("VS120COMNTOOLS"))
-    vcomntools = std::move(*vs120comntools);
-  else if (llvm::Optional<std::string> vs100comntools =
-               llvm::sys::Process::GetEnv("VS100COMNTOOLS"))
-    vcomntools = std::move(*vs100comntools);
-  else if (llvm::Optional<std::string> vs90comntools =
-               llvm::sys::Process::GetEnv("VS90COMNTOOLS"))
-    vcomntools = std::move(*vs90comntools);
-  else if (llvm::Optional<std::string> vs80comntools =
-               llvm::sys::Process::GetEnv("VS80COMNTOOLS"))
-    vcomntools = std::move(*vs80comntools);
-
-  // Find any version we can.
-  if (!vcomntools.empty()) {
-    size_t p = vcomntools.find("\\Common7\\Tools");
-    if (p != std::string::npos)
-      vcomntools.resize(p);
-    path = std::move(vcomntools);
-    return true;
-  }
-  return false;
-}
-
-void MSVCToolChain::AddSystemIncludeWithSubfolder(
-    const ArgList &DriverArgs, ArgStringList &CC1Args,
-    const std::string &folder, const Twine &subfolder1, const Twine &subfolder2,
-    const Twine &subfolder3) const {
-  llvm::SmallString<128> path(folder);
-  llvm::sys::path::append(path, subfolder1, subfolder2, subfolder3);
-  addSystemInclude(DriverArgs, CC1Args, path);
-}
-
-void MSVCToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
-                                              ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdinc))
-    return;
-
-  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
-    AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, getDriver().ResourceDir,
-                                  "include");
-  }
-
-  // Add %INCLUDE%-like directories from the -imsvc flag.
-  for (const auto &Path : DriverArgs.getAllArgValues(options::OPT__SLASH_imsvc))
-    addSystemInclude(DriverArgs, CC1Args, Path);
-
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
-    return;
-
-  // Honor %INCLUDE%. It should know essential search paths with vcvarsall.bat.
-  if (llvm::Optional<std::string> cl_include_dir =
-          llvm::sys::Process::GetEnv("INCLUDE")) {
-    SmallVector<StringRef, 8> Dirs;
-    StringRef(*cl_include_dir)
-        .split(Dirs, ";", /*MaxSplit=*/-1, /*KeepEmpty=*/false);
-    for (StringRef Dir : Dirs)
-      addSystemInclude(DriverArgs, CC1Args, Dir);
-    if (!Dirs.empty())
-      return;
-  }
-
-  std::string VSDir;
-
-  // When built with access to the proper Windows APIs, try to actually find
-  // the correct include paths first.
-  if (getVisualStudioInstallDir(VSDir)) {
-    AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, VSDir, "VC\\include");
-
-    if (useUniversalCRT(VSDir)) {
-      std::string UniversalCRTSdkPath;
-      std::string UCRTVersion;
-      if (getUniversalCRTSdkDir(UniversalCRTSdkPath, UCRTVersion)) {
-        AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, UniversalCRTSdkPath,
-                                      "Include", UCRTVersion, "ucrt");
-      }
-    }
-
-    std::string WindowsSDKDir;
-    int major;
-    std::string windowsSDKIncludeVersion;
-    std::string windowsSDKLibVersion;
-    if (getWindowsSDKDir(WindowsSDKDir, major, windowsSDKIncludeVersion,
-                         windowsSDKLibVersion)) {
-      if (major >= 8) {
-        // Note: windowsSDKIncludeVersion is empty for SDKs prior to v10.
-        // Anyway, llvm::sys::path::append is able to manage it.
-        AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, WindowsSDKDir,
-                                      "include", windowsSDKIncludeVersion,
-                                      "shared");
-        AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, WindowsSDKDir,
-                                      "include", windowsSDKIncludeVersion,
-                                      "um");
-        AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, WindowsSDKDir,
-                                      "include", windowsSDKIncludeVersion,
-                                      "winrt");
-      } else {
-        AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, WindowsSDKDir,
-                                      "include");
-      }
-    } else {
-      addSystemInclude(DriverArgs, CC1Args, VSDir);
-    }
-    return;
-  }
-
-#if defined(LLVM_ON_WIN32)
-  // As a fallback, select default install paths.
-  // FIXME: Don't guess drives and paths like this on Windows.
-  const StringRef Paths[] = {
-    "C:/Program Files/Microsoft Visual Studio 10.0/VC/include",
-    "C:/Program Files/Microsoft Visual Studio 9.0/VC/include",
-    "C:/Program Files/Microsoft Visual Studio 9.0/VC/PlatformSDK/Include",
-    "C:/Program Files/Microsoft Visual Studio 8/VC/include",
-    "C:/Program Files/Microsoft Visual Studio 8/VC/PlatformSDK/Include"
-  };
-  addSystemIncludes(DriverArgs, CC1Args, Paths);
-#endif
-}
-
-void MSVCToolChain::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
-                                                 ArgStringList &CC1Args) const {
-  // FIXME: There should probably be logic here to find libc++ on Windows.
-}
-
-VersionTuple MSVCToolChain::computeMSVCVersion(const Driver *D,
-                                               const ArgList &Args) const {
-  bool IsWindowsMSVC = getTriple().isWindowsMSVCEnvironment();
-  VersionTuple MSVT = ToolChain::computeMSVCVersion(D, Args);
-  if (MSVT.empty()) MSVT = getMSVCVersionFromTriple();
-  if (MSVT.empty() && IsWindowsMSVC) MSVT = getMSVCVersionFromExe();
-  if (MSVT.empty() &&
-      Args.hasFlag(options::OPT_fms_extensions, options::OPT_fno_ms_extensions,
-                   IsWindowsMSVC)) {
-    // -fms-compatibility-version=18.00 is default.
-    // FIXME: Consider bumping this to 19 (MSVC2015) soon.
-    MSVT = VersionTuple(18);
-  }
-  return MSVT;
-}
-
-std::string
-MSVCToolChain::ComputeEffectiveClangTriple(const ArgList &Args,
-                                           types::ID InputType) const {
-  // The MSVC version doesn't care about the architecture, even though it
-  // may look at the triple internally.
-  VersionTuple MSVT = computeMSVCVersion(/*D=*/nullptr, Args);
-  MSVT = VersionTuple(MSVT.getMajor(), MSVT.getMinor().getValueOr(0),
-                      MSVT.getSubminor().getValueOr(0));
-
-  // For the rest of the triple, however, a computed architecture name may
-  // be needed.
-  llvm::Triple Triple(ToolChain::ComputeEffectiveClangTriple(Args, InputType));
-  if (Triple.getEnvironment() == llvm::Triple::MSVC) {
-    StringRef ObjFmt = Triple.getEnvironmentName().split('-').second;
-    if (ObjFmt.empty())
-      Triple.setEnvironmentName((Twine("msvc") + MSVT.getAsString()).str());
-    else
-      Triple.setEnvironmentName(
-          (Twine("msvc") + MSVT.getAsString() + Twine('-') + ObjFmt).str());
-  }
-  return Triple.getTriple();
-}
-
-SanitizerMask MSVCToolChain::getSupportedSanitizers() const {
-  SanitizerMask Res = ToolChain::getSupportedSanitizers();
-  Res |= SanitizerKind::Address;
-  return Res;
-}
-
-static void TranslateOptArg(Arg *A, llvm::opt::DerivedArgList &DAL,
-                            bool SupportsForcingFramePointer,
-                            const char *ExpandChar, const OptTable &Opts) {
-  assert(A->getOption().matches(options::OPT__SLASH_O));
-
-  StringRef OptStr = A->getValue();
-  for (size_t I = 0, E = OptStr.size(); I != E; ++I) {
-    const char &OptChar = *(OptStr.data() + I);
-    switch (OptChar) {
-    default:
-      break;
-    case '1':
-    case '2':
-    case 'x':
-    case 'd':
-      if (&OptChar == ExpandChar) {
-        if (OptChar == 'd') {
-          DAL.AddFlagArg(A, Opts.getOption(options::OPT_O0));
-        } else {
-          if (OptChar == '1') {
-            DAL.AddJoinedArg(A, Opts.getOption(options::OPT_O), "s");
-          } else if (OptChar == '2' || OptChar == 'x') {
-            DAL.AddFlagArg(A, Opts.getOption(options::OPT_fbuiltin));
-            DAL.AddJoinedArg(A, Opts.getOption(options::OPT_O), "2");
-          }
-          if (SupportsForcingFramePointer &&
-              !DAL.hasArgNoClaim(options::OPT_fno_omit_frame_pointer))
-            DAL.AddFlagArg(A,
-                           Opts.getOption(options::OPT_fomit_frame_pointer));
-          if (OptChar == '1' || OptChar == '2')
-            DAL.AddFlagArg(A,
-                           Opts.getOption(options::OPT_ffunction_sections));
-        }
-      }
-      break;
-    case 'b':
-      if (I + 1 != E && isdigit(OptStr[I + 1])) {
-        switch (OptStr[I + 1]) {
-        case '0':
-          DAL.AddFlagArg(A, Opts.getOption(options::OPT_fno_inline));
-          break;
-        case '1':
-          DAL.AddFlagArg(A, Opts.getOption(options::OPT_finline_hint_functions));
-          break;
-        case '2':
-          DAL.AddFlagArg(A, Opts.getOption(options::OPT_finline_functions));
-          break;
-        }
-        ++I;
-      }
-      break;
-    case 'g':
-      break;
-    case 'i':
-      if (I + 1 != E && OptStr[I + 1] == '-') {
-        ++I;
-        DAL.AddFlagArg(A, Opts.getOption(options::OPT_fno_builtin));
-      } else {
-        DAL.AddFlagArg(A, Opts.getOption(options::OPT_fbuiltin));
-      }
-      break;
-    case 's':
-      DAL.AddJoinedArg(A, Opts.getOption(options::OPT_O), "s");
-      break;
-    case 't':
-      DAL.AddJoinedArg(A, Opts.getOption(options::OPT_O), "2");
-      break;
-    case 'y': {
-      bool OmitFramePointer = true;
-      if (I + 1 != E && OptStr[I + 1] == '-') {
-        OmitFramePointer = false;
-        ++I;
-      }
-      if (SupportsForcingFramePointer) {
-        if (OmitFramePointer)
-          DAL.AddFlagArg(A,
-                         Opts.getOption(options::OPT_fomit_frame_pointer));
-        else
-          DAL.AddFlagArg(
-              A, Opts.getOption(options::OPT_fno_omit_frame_pointer));
-      } else {
-        // Don't warn about /Oy- in 64-bit builds (where
-        // SupportsForcingFramePointer is false).  The flag having no effect
-        // there is a compiler-internal optimization, and people shouldn't have
-        // to special-case their build files for 64-bit clang-cl.
-        A->claim();
-      }
-      break;
-    }
-    }
-  }
-}
-
-static void TranslateDArg(Arg *A, llvm::opt::DerivedArgList &DAL,
-                          const OptTable &Opts) {
-  assert(A->getOption().matches(options::OPT_D));
-
-  StringRef Val = A->getValue();
-  size_t Hash = Val.find('#');
-  if (Hash == StringRef::npos || Hash > Val.find('=')) {
-    DAL.append(A);
-    return;
-  }
-
-  std::string NewVal = Val;
-  NewVal[Hash] = '=';
-  DAL.AddJoinedArg(A, Opts.getOption(options::OPT_D), NewVal);
-}
-
-llvm::opt::DerivedArgList *
-MSVCToolChain::TranslateArgs(const llvm::opt::DerivedArgList &Args,
-                             StringRef BoundArch, Action::OffloadKind) const {
-  DerivedArgList *DAL = new DerivedArgList(Args.getBaseArgs());
-  const OptTable &Opts = getDriver().getOpts();
-
-  // /Oy and /Oy- only has an effect under X86-32.
-  bool SupportsForcingFramePointer = getArch() == llvm::Triple::x86;
-
-  // The -O[12xd] flag actually expands to several flags.  We must desugar the
-  // flags so that options embedded can be negated.  For example, the '-O2' flag
-  // enables '-Oy'.  Expanding '-O2' into its constituent flags allows us to
-  // correctly handle '-O2 -Oy-' where the trailing '-Oy-' disables a single
-  // aspect of '-O2'.
-  //
-  // Note that this expansion logic only applies to the *last* of '[12xd]'.
-
-  // First step is to search for the character we'd like to expand.
-  const char *ExpandChar = nullptr;
-  for (Arg *A : Args) {
-    if (!A->getOption().matches(options::OPT__SLASH_O))
-      continue;
-    StringRef OptStr = A->getValue();
-    for (size_t I = 0, E = OptStr.size(); I != E; ++I) {
-      char OptChar = OptStr[I];
-      char PrevChar = I > 0 ? OptStr[I - 1] : '0';
-      if (PrevChar == 'b') {
-        // OptChar does not expand; it's an argument to the previous char.
-        continue;
-      }
-      if (OptChar == '1' || OptChar == '2' || OptChar == 'x' || OptChar == 'd')
-        ExpandChar = OptStr.data() + I;
-    }
-  }
-
-  for (Arg *A : Args) {
-    if (A->getOption().matches(options::OPT__SLASH_O)) {
-      // The -O flag actually takes an amalgam of other options.  For example,
-      // '/Ogyb2' is equivalent to '/Og' '/Oy' '/Ob2'.
-      TranslateOptArg(A, *DAL, SupportsForcingFramePointer, ExpandChar, Opts);
-    } else if (A->getOption().matches(options::OPT_D)) {
-      // Translate -Dfoo#bar into -Dfoo=bar.
-      TranslateDArg(A, *DAL, Opts);
-    } else {
-      DAL->append(A);
-    }
-  }
-
-  return DAL;
-}
diff --git a/lib/Driver/MinGWToolChain.cpp b/lib/Driver/MinGWToolChain.cpp
deleted file mode 100644
index e971869fb569..000000000000
--- a/lib/Driver/MinGWToolChain.cpp
+++ /dev/null
@@ -1,257 +0,0 @@
-//===--- MinGWToolChain.cpp - MinGWToolChain Implementation ---------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#include "ToolChains.h"
-#include "clang/Driver/Driver.h"
-#include "clang/Driver/Options.h"
-#include "llvm/Option/ArgList.h"
-#include "llvm/Support/FileSystem.h"
-#include "llvm/Support/Path.h"
-
-using namespace clang::diag;
-using namespace clang::driver;
-using namespace clang::driver::toolchains;
-using namespace clang;
-using namespace llvm::opt;
-
-// Simplified from Generic_GCC::GCCInstallationDetector::ScanLibDirForGCCTriple.
-static bool findGccVersion(StringRef LibDir, std::string &GccLibDir,
-                           std::string &Ver) {
-  Generic_GCC::GCCVersion Version = Generic_GCC::GCCVersion::Parse("0.0.0");
-  std::error_code EC;
-  for (llvm::sys::fs::directory_iterator LI(LibDir, EC), LE; !EC && LI != LE;
-       LI = LI.increment(EC)) {
-    StringRef VersionText = llvm::sys::path::filename(LI->path());
-    Generic_GCC::GCCVersion CandidateVersion =
-        Generic_GCC::GCCVersion::Parse(VersionText);
-    if (CandidateVersion.Major == -1)
-      continue;
-    if (CandidateVersion <= Version)
-      continue;
-    Ver = VersionText;
-    GccLibDir = LI->path();
-  }
-  return Ver.size();
-}
-
-void MinGW::findGccLibDir() {
-  llvm::SmallVector<llvm::SmallString<32>, 2> Archs;
-  Archs.emplace_back(getTriple().getArchName());
-  Archs[0] += "-w64-mingw32";
-  Archs.emplace_back("mingw32");
-  Arch = Archs[0].str();
-  // lib: Arch Linux, Ubuntu, Windows
-  // lib64: openSUSE Linux
-  for (StringRef CandidateLib : {"lib", "lib64"}) {
-    for (StringRef CandidateArch : Archs) {
-      llvm::SmallString<1024> LibDir(Base);
-      llvm::sys::path::append(LibDir, CandidateLib, "gcc", CandidateArch);
-      if (findGccVersion(LibDir, GccLibDir, Ver)) {
-        Arch = CandidateArch;
-        return;
-      }
-    }
-  }
-}
-
-MinGW::MinGW(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
-    : ToolChain(D, Triple, Args), CudaInstallation(D, Triple, Args) {
-  getProgramPaths().push_back(getDriver().getInstalledDir());
-
-// In Windows there aren't any standard install locations, we search
-// for gcc on the PATH. In Linux the base is always /usr.
-#ifdef LLVM_ON_WIN32
-  if (getDriver().SysRoot.size())
-    Base = getDriver().SysRoot;
-  else if (llvm::ErrorOr<std::string> GPPName =
-               llvm::sys::findProgramByName("gcc"))
-    Base = llvm::sys::path::parent_path(
-        llvm::sys::path::parent_path(GPPName.get()));
-  else
-    Base = llvm::sys::path::parent_path(getDriver().getInstalledDir());
-#else
-  if (getDriver().SysRoot.size())
-    Base = getDriver().SysRoot;
-  else
-    Base = "/usr";
-#endif
-
-  Base += llvm::sys::path::get_separator();
-  findGccLibDir();
-  // GccLibDir must precede Base/lib so that the
-  // correct crtbegin.o ,cetend.o would be found.
-  getFilePaths().push_back(GccLibDir);
-  getFilePaths().push_back(
-      (Base + Arch + llvm::sys::path::get_separator() + "lib").str());
-  getFilePaths().push_back(Base + "lib");
-  // openSUSE
-  getFilePaths().push_back(Base + Arch + "/sys-root/mingw/lib");
-}
-
-bool MinGW::IsIntegratedAssemblerDefault() const { return true; }
-
-Tool *MinGW::getTool(Action::ActionClass AC) const {
-  switch (AC) {
-  case Action::PreprocessJobClass:
-    if (!Preprocessor)
-      Preprocessor.reset(new tools::gcc::Preprocessor(*this));
-    return Preprocessor.get();
-  case Action::CompileJobClass:
-    if (!Compiler)
-      Compiler.reset(new tools::gcc::Compiler(*this));
-    return Compiler.get();
-  default:
-    return ToolChain::getTool(AC);
-  }
-}
-
-Tool *MinGW::buildAssembler() const {
-  return new tools::MinGW::Assembler(*this);
-}
-
-Tool *MinGW::buildLinker() const { return new tools::MinGW::Linker(*this); }
-
-bool MinGW::IsUnwindTablesDefault() const {
-  return getArch() == llvm::Triple::x86_64;
-}
-
-bool MinGW::isPICDefault() const { return getArch() == llvm::Triple::x86_64; }
-
-bool MinGW::isPIEDefault() const { return false; }
-
-bool MinGW::isPICDefaultForced() const {
-  return getArch() == llvm::Triple::x86_64;
-}
-
-bool MinGW::UseSEHExceptions() const {
-  return getArch() == llvm::Triple::x86_64;
-}
-
-void MinGW::AddCudaIncludeArgs(const ArgList &DriverArgs,
-                               ArgStringList &CC1Args) const {
-  CudaInstallation.AddCudaIncludeArgs(DriverArgs, CC1Args);
-}
-
-void MinGW::printVerboseInfo(raw_ostream &OS) const {
-  CudaInstallation.print(OS);
-}
-
-// Include directories for various hosts:
-
-// Windows, mingw.org
-// c:\mingw\lib\gcc\mingw32\4.8.1\include\c++
-// c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\mingw32
-// c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\backward
-// c:\mingw\lib\gcc\mingw32\4.8.1\include
-// c:\mingw\include
-// c:\mingw\lib\gcc\mingw32\4.8.1\include-fixed
-// c:\mingw\mingw32\include
-
-// Windows, mingw-w64 mingw-builds
-// c:\mingw32\lib\gcc\i686-w64-mingw32\4.9.1\include
-// c:\mingw32\lib\gcc\i686-w64-mingw32\4.9.1\include-fixed
-// c:\mingw32\i686-w64-mingw32\include
-// c:\mingw32\i686-w64-mingw32\include\c++
-// c:\mingw32\i686-w64-mingw32\include\c++\i686-w64-mingw32
-// c:\mingw32\i686-w64-mingw32\include\c++\backward
-
-// Windows, mingw-w64 msys2
-// c:\msys64\mingw32\lib\gcc\i686-w64-mingw32\4.9.2\include
-// c:\msys64\mingw32\include
-// c:\msys64\mingw32\lib\gcc\i686-w64-mingw32\4.9.2\include-fixed
-// c:\msys64\mingw32\i686-w64-mingw32\include
-// c:\msys64\mingw32\include\c++\4.9.2
-// c:\msys64\mingw32\include\c++\4.9.2\i686-w64-mingw32
-// c:\msys64\mingw32\include\c++\4.9.2\backward
-
-// openSUSE
-// /usr/lib64/gcc/x86_64-w64-mingw32/5.1.0/include/c++
-// /usr/lib64/gcc/x86_64-w64-mingw32/5.1.0/include/c++/x86_64-w64-mingw32
-// /usr/lib64/gcc/x86_64-w64-mingw32/5.1.0/include/c++/backward
-// /usr/lib64/gcc/x86_64-w64-mingw32/5.1.0/include
-// /usr/lib64/gcc/x86_64-w64-mingw32/5.1.0/include-fixed
-// /usr/x86_64-w64-mingw32/sys-root/mingw/include
-
-// Arch Linux
-// /usr/i686-w64-mingw32/include/c++/5.1.0
-// /usr/i686-w64-mingw32/include/c++/5.1.0/i686-w64-mingw32
-// /usr/i686-w64-mingw32/include/c++/5.1.0/backward
-// /usr/lib/gcc/i686-w64-mingw32/5.1.0/include
-// /usr/lib/gcc/i686-w64-mingw32/5.1.0/include-fixed
-// /usr/i686-w64-mingw32/include
-
-// Ubuntu
-// /usr/include/c++/4.8
-// /usr/include/c++/4.8/x86_64-w64-mingw32
-// /usr/include/c++/4.8/backward
-// /usr/lib/gcc/x86_64-w64-mingw32/4.8/include
-// /usr/lib/gcc/x86_64-w64-mingw32/4.8/include-fixed
-// /usr/x86_64-w64-mingw32/include
-
-void MinGW::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
-                                      ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdinc))
-    return;
-
-  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
-    SmallString<1024> P(getDriver().ResourceDir);
-    llvm::sys::path::append(P, "include");
-    addSystemInclude(DriverArgs, CC1Args, P.str());
-  }
-
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
-    return;
-
-  if (GetRuntimeLibType(DriverArgs) == ToolChain::RLT_Libgcc) {
-    llvm::SmallString<1024> IncludeDir(GccLibDir);
-    llvm::sys::path::append(IncludeDir, "include");
-    addSystemInclude(DriverArgs, CC1Args, IncludeDir.c_str());
-    IncludeDir += "-fixed";
-    // openSUSE
-    addSystemInclude(DriverArgs, CC1Args,
-                     Base + Arch + "/sys-root/mingw/include");
-    addSystemInclude(DriverArgs, CC1Args, IncludeDir.c_str());
-  }
-  addSystemInclude(DriverArgs, CC1Args,
-                   Base + Arch + llvm::sys::path::get_separator() + "include");
-  addSystemInclude(DriverArgs, CC1Args, Base + "include");
-}
-
-void MinGW::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
-                                         ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
-      DriverArgs.hasArg(options::OPT_nostdincxx))
-    return;
-
-  switch (GetCXXStdlibType(DriverArgs)) {
-  case ToolChain::CST_Libcxx:
-    addSystemInclude(DriverArgs, CC1Args,
-                     Base + "include" + llvm::sys::path::get_separator() +
-                         "c++" + llvm::sys::path::get_separator() + "v1");
-    break;
-
-  case ToolChain::CST_Libstdcxx:
-    llvm::SmallVector<llvm::SmallString<1024>, 4> CppIncludeBases;
-    CppIncludeBases.emplace_back(Base);
-    llvm::sys::path::append(CppIncludeBases[0], Arch, "include", "c++");
-    CppIncludeBases.emplace_back(Base);
-    llvm::sys::path::append(CppIncludeBases[1], Arch, "include", "c++", Ver);
-    CppIncludeBases.emplace_back(Base);
-    llvm::sys::path::append(CppIncludeBases[2], "include", "c++", Ver);
-    CppIncludeBases.emplace_back(GccLibDir);
-    llvm::sys::path::append(CppIncludeBases[3], "include", "c++");
-    for (auto &CppIncludeBase : CppIncludeBases) {
-      addSystemInclude(DriverArgs, CC1Args, CppIncludeBase);
-      CppIncludeBase += llvm::sys::path::get_separator();
-      addSystemInclude(DriverArgs, CC1Args, CppIncludeBase + Arch);
-      addSystemInclude(DriverArgs, CC1Args, CppIncludeBase + "backward");
-    }
-    break;
-  }
-}
diff --git a/lib/Driver/Multilib.cpp b/lib/Driver/Multilib.cpp
index a88edf7f04e3..43b62f7b3612 100644
--- a/lib/Driver/Multilib.cpp
+++ b/lib/Driver/Multilib.cpp
@@ -8,7 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Driver/Multilib.h"
-#include "Tools.h"
+#include "ToolChains/CommonArgs.h"
 #include "clang/Driver/Options.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
diff --git a/lib/Driver/SanitizerArgs.cpp b/lib/Driver/SanitizerArgs.cpp
index f4f6dad9f287..b05596a99f6e 100644
--- a/lib/Driver/SanitizerArgs.cpp
+++ b/lib/Driver/SanitizerArgs.cpp
@@ -7,7 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 #include "clang/Driver/SanitizerArgs.h"
-#include "Tools.h"
+#include "ToolChains/CommonArgs.h"
 #include "clang/Basic/Sanitizers.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/DriverDiagnostic.h"
@@ -26,18 +26,19 @@ using namespace clang::driver;
 using namespace llvm::opt;
 
 enum : SanitizerMask {
-  NeedsUbsanRt = Undefined | Integer | CFI,
+  NeedsUbsanRt = Undefined | Integer | Nullability | CFI,
   NeedsUbsanCxxRt = Vptr | CFI,
   NotAllowedWithTrap = Vptr,
   RequiresPIE = DataFlow,
   NeedsUnwindTables = Address | Thread | Memory | DataFlow,
-  SupportsCoverage = Address | Memory | Leak | Undefined | Integer | DataFlow,
-  RecoverableByDefault = Undefined | Integer,
+  SupportsCoverage =
+      Address | Memory | Leak | Undefined | Integer | Nullability | DataFlow,
+  RecoverableByDefault = Undefined | Integer | Nullability,
   Unrecoverable = Unreachable | Return,
   LegacyFsanitizeRecoverMask = Undefined | Integer,
   NeedsLTO = CFI,
-  TrappingSupported =
-      (Undefined & ~Vptr) | UnsignedIntegerOverflow | LocalBounds | CFI,
+  TrappingSupported = (Undefined & ~Vptr) | UnsignedIntegerOverflow |
+                      Nullability | LocalBounds | CFI,
   TrappingDefault = CFI,
   CFIClasses = CFIVCall | CFINVCall | CFIDerivedCast | CFIUnrelatedCast,
 };
diff --git a/lib/Driver/ToolChain.cpp b/lib/Driver/ToolChain.cpp
index 6adc0386ee7b..4f82503276f4 100644
--- a/lib/Driver/ToolChain.cpp
+++ b/lib/Driver/ToolChain.cpp
@@ -8,14 +8,18 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Driver/ToolChain.h"
-#include "Tools.h"
+#include "ToolChains/CommonArgs.h"
+#include "ToolChains/Arch/ARM.h"
+#include "ToolChains/Clang.h"
 #include "clang/Basic/ObjCRuntime.h"
+#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Config/config.h"
 #include "clang/Driver/Action.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/SanitizerArgs.h"
+#include "clang/Driver/XRayArgs.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
@@ -74,6 +78,10 @@ ToolChain::ToolChain(const Driver &D, const llvm::Triple &T,
     if (!isThreadModelSupported(A->getValue()))
       D.Diag(diag::err_drv_invalid_thread_model_for_target)
           << A->getValue() << A->getAsString(Args);
+
+  std::string CandidateLibPath = getArchSpecificLibPath();
+  if (getVFS().exists(CandidateLibPath))
+    getFilePaths().push_back(CandidateLibPath);
 }
 
 ToolChain::~ToolChain() {
@@ -93,6 +101,12 @@ const SanitizerArgs& ToolChain::getSanitizerArgs() const {
   return *SanitizerArguments.get();
 }
 
+const XRayArgs& ToolChain::getXRayArgs() const {
+  if (!XRayArguments.get())
+    XRayArguments.reset(new XRayArgs(*this, Args));
+  return *XRayArguments.get();
+}
+
 namespace {
 struct DriverSuffix {
   const char *Suffix;
@@ -320,6 +334,14 @@ const char *ToolChain::getCompilerRTArgString(const llvm::opt::ArgList &Args,
   return Args.MakeArgString(getCompilerRT(Args, Component, Shared));
 }
 
+std::string ToolChain::getArchSpecificLibPath() const {
+  SmallString<128> Path(getDriver().ResourceDir);
+  StringRef OSLibName = getTriple().isOSFreeBSD() ? "freebsd" : getOS();
+  llvm::sys::path::append(Path, "lib", OSLibName,
+                          llvm::Triple::getArchTypeName(getArch()));
+  return Path.str();
+}
+
 bool ToolChain::needsProfileRT(const ArgList &Args) {
   if (Args.hasFlag(options::OPT_fprofile_arcs, options::OPT_fno_profile_arcs,
                    false) ||
@@ -682,7 +704,8 @@ SanitizerMask ToolChain::getSupportedSanitizers() const {
   // platform dependent.
   using namespace SanitizerKind;
   SanitizerMask Res = (Undefined & ~Vptr & ~Function) | (CFI & ~CFIICall) |
-                      CFICastStrict | UnsignedIntegerOverflow | LocalBounds;
+                      CFICastStrict | UnsignedIntegerOverflow | Nullability |
+                      LocalBounds;
   if (getTriple().getArch() == llvm::Triple::x86 ||
       getTriple().getArch() == llvm::Triple::x86_64 ||
       getTriple().getArch() == llvm::Triple::arm ||
diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
deleted file mode 100644
index 9bc9ae4f6a52..000000000000
--- a/lib/Driver/ToolChains.cpp
+++ /dev/null
@@ -1,5342 +0,0 @@
-//===--- ToolChains.cpp - ToolChain Implementations -------------*- C++ -*-===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#include "ToolChains.h"
-#include "clang/Basic/Cuda.h"
-#include "clang/Basic/ObjCRuntime.h"
-#include "clang/Basic/Version.h"
-#include "clang/Basic/VirtualFileSystem.h"
-#include "clang/Config/config.h" // for GCC_INSTALL_PREFIX
-#include "clang/Driver/Compilation.h"
-#include "clang/Driver/Distro.h"
-#include "clang/Driver/Driver.h"
-#include "clang/Driver/DriverDiagnostic.h"
-#include "clang/Driver/Options.h"
-#include "clang/Driver/SanitizerArgs.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/SmallString.h"
-#include "llvm/ADT/StringExtras.h"
-#include "llvm/ADT/StringSwitch.h"
-#include "llvm/Option/Arg.h"
-#include "llvm/Option/ArgList.h"
-#include "llvm/Option/OptTable.h"
-#include "llvm/Option/Option.h"
-#include "llvm/ProfileData/InstrProf.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/FileSystem.h"
-#include "llvm/Support/MemoryBuffer.h"
-#include "llvm/Support/Path.h"
-#include "llvm/Support/Program.h"
-#include "llvm/Support/TargetParser.h"
-#include "llvm/Support/raw_ostream.h"
-#include <cstdlib> // ::getenv
-#include <system_error>
-
-using namespace clang::driver;
-using namespace clang::driver::toolchains;
-using namespace clang;
-using namespace llvm::opt;
-
-MachO::MachO(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
-    : ToolChain(D, Triple, Args) {
-  // We expect 'as', 'ld', etc. to be adjacent to our install dir.
-  getProgramPaths().push_back(getDriver().getInstalledDir());
-  if (getDriver().getInstalledDir() != getDriver().Dir)
-    getProgramPaths().push_back(getDriver().Dir);
-}
-
-/// Darwin - Darwin tool chain for i386 and x86_64.
-Darwin::Darwin(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
-    : MachO(D, Triple, Args), TargetInitialized(false),
-      CudaInstallation(D, Triple, Args) {}
-
-types::ID MachO::LookupTypeForExtension(StringRef Ext) const {
-  types::ID Ty = types::lookupTypeForExtension(Ext);
-
-  // Darwin always preprocesses assembly files (unless -x is used explicitly).
-  if (Ty == types::TY_PP_Asm)
-    return types::TY_Asm;
-
-  return Ty;
-}
-
-bool MachO::HasNativeLLVMSupport() const { return true; }
-
-ToolChain::CXXStdlibType Darwin::GetDefaultCXXStdlibType() const {
-  // Default to use libc++ on OS X 10.9+ and iOS 7+.
-  if ((isTargetMacOS() && !isMacosxVersionLT(10, 9)) ||
-       (isTargetIOSBased() && !isIPhoneOSVersionLT(7, 0)) ||
-       isTargetWatchOSBased())
-    return ToolChain::CST_Libcxx;
-
-  return ToolChain::CST_Libstdcxx;
-}
-
-/// Darwin provides an ARC runtime starting in MacOS X 10.7 and iOS 5.0.
-ObjCRuntime Darwin::getDefaultObjCRuntime(bool isNonFragile) const {
-  if (isTargetWatchOSBased())
-    return ObjCRuntime(ObjCRuntime::WatchOS, TargetVersion);
-  if (isTargetIOSBased())
-    return ObjCRuntime(ObjCRuntime::iOS, TargetVersion);
-  if (isNonFragile)
-    return ObjCRuntime(ObjCRuntime::MacOSX, TargetVersion);
-  return ObjCRuntime(ObjCRuntime::FragileMacOSX, TargetVersion);
-}
-
-/// Darwin provides a blocks runtime starting in MacOS X 10.6 and iOS 3.2.
-bool Darwin::hasBlocksRuntime() const {
-  if (isTargetWatchOSBased())
-    return true;
-  else if (isTargetIOSBased())
-    return !isIPhoneOSVersionLT(3, 2);
-  else {
-    assert(isTargetMacOS() && "unexpected darwin target");
-    return !isMacosxVersionLT(10, 6);
-  }
-}
-
-void Darwin::AddCudaIncludeArgs(const ArgList &DriverArgs,
-                                ArgStringList &CC1Args) const {
-  CudaInstallation.AddCudaIncludeArgs(DriverArgs, CC1Args);
-}
-
-// This is just a MachO name translation routine and there's no
-// way to join this into ARMTargetParser without breaking all
-// other assumptions. Maybe MachO should consider standardising
-// their nomenclature.
-static const char *ArmMachOArchName(StringRef Arch) {
-  return llvm::StringSwitch<const char *>(Arch)
-      .Case("armv6k", "armv6")
-      .Case("armv6m", "armv6m")
-      .Case("armv5tej", "armv5")
-      .Case("xscale", "xscale")
-      .Case("armv4t", "armv4t")
-      .Case("armv7", "armv7")
-      .Cases("armv7a", "armv7-a", "armv7")
-      .Cases("armv7r", "armv7-r", "armv7")
-      .Cases("armv7em", "armv7e-m", "armv7em")
-      .Cases("armv7k", "armv7-k", "armv7k")
-      .Cases("armv7m", "armv7-m", "armv7m")
-      .Cases("armv7s", "armv7-s", "armv7s")
-      .Default(nullptr);
-}
-
-static const char *ArmMachOArchNameCPU(StringRef CPU) {
-  unsigned ArchKind = llvm::ARM::parseCPUArch(CPU);
-  if (ArchKind == llvm::ARM::AK_INVALID)
-    return nullptr;
-  StringRef Arch = llvm::ARM::getArchName(ArchKind);
-
-  // FIXME: Make sure this MachO triple mangling is really necessary.
-  // ARMv5* normalises to ARMv5.
-  if (Arch.startswith("armv5"))
-    Arch = Arch.substr(0, 5);
-  // ARMv6*, except ARMv6M, normalises to ARMv6.
-  else if (Arch.startswith("armv6") && !Arch.endswith("6m"))
-    Arch = Arch.substr(0, 5);
-  // ARMv7A normalises to ARMv7.
-  else if (Arch.endswith("v7a"))
-    Arch = Arch.substr(0, 5);
-  return Arch.data();
-}
-
-static bool isSoftFloatABI(const ArgList &Args) {
-  Arg *A = Args.getLastArg(options::OPT_msoft_float, options::OPT_mhard_float,
-                           options::OPT_mfloat_abi_EQ);
-  if (!A)
-    return false;
-
-  return A->getOption().matches(options::OPT_msoft_float) ||
-         (A->getOption().matches(options::OPT_mfloat_abi_EQ) &&
-          A->getValue() == StringRef("soft"));
-}
-
-StringRef MachO::getMachOArchName(const ArgList &Args) const {
-  switch (getTriple().getArch()) {
-  default:
-    return getDefaultUniversalArchName();
-
-  case llvm::Triple::aarch64:
-    return "arm64";
-
-  case llvm::Triple::thumb:
-  case llvm::Triple::arm:
-    if (const Arg *A = Args.getLastArg(options::OPT_march_EQ))
-      if (const char *Arch = ArmMachOArchName(A->getValue()))
-        return Arch;
-
-    if (const Arg *A = Args.getLastArg(options::OPT_mcpu_EQ))
-      if (const char *Arch = ArmMachOArchNameCPU(A->getValue()))
-        return Arch;
-
-    return "arm";
-  }
-}
-
-Darwin::~Darwin() {}
-
-MachO::~MachO() {}
-
-std::string Darwin::ComputeEffectiveClangTriple(const ArgList &Args,
-                                                types::ID InputType) const {
-  llvm::Triple Triple(ComputeLLVMTriple(Args, InputType));
-
-  // If the target isn't initialized (e.g., an unknown Darwin platform, return
-  // the default triple).
-  if (!isTargetInitialized())
-    return Triple.getTriple();
-
-  SmallString<16> Str;
-  if (isTargetWatchOSBased())
-    Str += "watchos";
-  else if (isTargetTvOSBased())
-    Str += "tvos";
-  else if (isTargetIOSBased())
-    Str += "ios";
-  else
-    Str += "macosx";
-  Str += getTargetVersion().getAsString();
-  Triple.setOSName(Str);
-
-  return Triple.getTriple();
-}
-
-void Generic_ELF::anchor() {}
-
-Tool *MachO::getTool(Action::ActionClass AC) const {
-  switch (AC) {
-  case Action::LipoJobClass:
-    if (!Lipo)
-      Lipo.reset(new tools::darwin::Lipo(*this));
-    return Lipo.get();
-  case Action::DsymutilJobClass:
-    if (!Dsymutil)
-      Dsymutil.reset(new tools::darwin::Dsymutil(*this));
-    return Dsymutil.get();
-  case Action::VerifyDebugInfoJobClass:
-    if (!VerifyDebug)
-      VerifyDebug.reset(new tools::darwin::VerifyDebug(*this));
-    return VerifyDebug.get();
-  default:
-    return ToolChain::getTool(AC);
-  }
-}
-
-Tool *MachO::buildLinker() const { return new tools::darwin::Linker(*this); }
-
-Tool *MachO::buildAssembler() const {
-  return new tools::darwin::Assembler(*this);
-}
-
-DarwinClang::DarwinClang(const Driver &D, const llvm::Triple &Triple,
-                         const ArgList &Args)
-    : Darwin(D, Triple, Args) {}
-
-void DarwinClang::addClangWarningOptions(ArgStringList &CC1Args) const {
-  // For modern targets, promote certain warnings to errors.
-  if (isTargetWatchOSBased() || getTriple().isArch64Bit()) {
-    // Always enable -Wdeprecated-objc-isa-usage and promote it
-    // to an error.
-    CC1Args.push_back("-Wdeprecated-objc-isa-usage");
-    CC1Args.push_back("-Werror=deprecated-objc-isa-usage");
-
-    // For iOS and watchOS, also error about implicit function declarations,
-    // as that can impact calling conventions.
-    if (!isTargetMacOS())
-      CC1Args.push_back("-Werror=implicit-function-declaration");
-  }
-}
-
-/// \brief Determine whether Objective-C automated reference counting is
-/// enabled.
-static bool isObjCAutoRefCount(const ArgList &Args) {
-  return Args.hasFlag(options::OPT_fobjc_arc, options::OPT_fno_objc_arc, false);
-}
-
-void DarwinClang::AddLinkARCArgs(const ArgList &Args,
-                                 ArgStringList &CmdArgs) const {
-  // Avoid linking compatibility stubs on i386 mac.
-  if (isTargetMacOS() && getArch() == llvm::Triple::x86)
-    return;
-
-  ObjCRuntime runtime = getDefaultObjCRuntime(/*nonfragile*/ true);
-
-  if ((runtime.hasNativeARC() || !isObjCAutoRefCount(Args)) &&
-      runtime.hasSubscripting())
-    return;
-
-  CmdArgs.push_back("-force_load");
-  SmallString<128> P(getDriver().ClangExecutable);
-  llvm::sys::path::remove_filename(P); // 'clang'
-  llvm::sys::path::remove_filename(P); // 'bin'
-  llvm::sys::path::append(P, "lib", "arc", "libarclite_");
-  // Mash in the platform.
-  if (isTargetWatchOSSimulator())
-    P += "watchsimulator";
-  else if (isTargetWatchOS())
-    P += "watchos";
-  else if (isTargetTvOSSimulator())
-    P += "appletvsimulator";
-  else if (isTargetTvOS())
-    P += "appletvos";
-  else if (isTargetIOSSimulator())
-    P += "iphonesimulator";
-  else if (isTargetIPhoneOS())
-    P += "iphoneos";
-  else
-    P += "macosx";
-  P += ".a";
-
-  CmdArgs.push_back(Args.MakeArgString(P));
-}
-
-unsigned DarwinClang::GetDefaultDwarfVersion() const {
-  // Default to use DWARF 2 on OS X 10.10 / iOS 8 and lower.
-  if ((isTargetMacOS() && isMacosxVersionLT(10, 11)) ||
-      (isTargetIOSBased() && isIPhoneOSVersionLT(9)))
-    return 2;
-  return 4;
-}
-
-void MachO::AddLinkRuntimeLib(const ArgList &Args, ArgStringList &CmdArgs,
-                              StringRef DarwinLibName, bool AlwaysLink,
-                              bool IsEmbedded, bool AddRPath) const {
-  SmallString<128> Dir(getDriver().ResourceDir);
-  llvm::sys::path::append(Dir, "lib", IsEmbedded ? "macho_embedded" : "darwin");
-
-  SmallString<128> P(Dir);
-  llvm::sys::path::append(P, DarwinLibName);
-
-  // For now, allow missing resource libraries to support developers who may
-  // not have compiler-rt checked out or integrated into their build (unless
-  // we explicitly force linking with this library).
-  if (AlwaysLink || getVFS().exists(P))
-    CmdArgs.push_back(Args.MakeArgString(P));
-
-  // Adding the rpaths might negatively interact when other rpaths are involved,
-  // so we should make sure we add the rpaths last, after all user-specified
-  // rpaths. This is currently true from this place, but we need to be
-  // careful if this function is ever called before user's rpaths are emitted.
-  if (AddRPath) {
-    assert(DarwinLibName.endswith(".dylib") && "must be a dynamic library");
-
-    // Add @executable_path to rpath to support having the dylib copied with
-    // the executable.
-    CmdArgs.push_back("-rpath");
-    CmdArgs.push_back("@executable_path");
-
-    // Add the path to the resource dir to rpath to support using the dylib
-    // from the default location without copying.
-    CmdArgs.push_back("-rpath");
-    CmdArgs.push_back(Args.MakeArgString(Dir));
-  }
-}
-
-StringRef Darwin::getPlatformFamily() const {
-  switch (TargetPlatform) {
-    case DarwinPlatformKind::MacOS:
-      return "MacOSX";
-    case DarwinPlatformKind::IPhoneOS:
-    case DarwinPlatformKind::IPhoneOSSimulator:
-      return "iPhone";
-    case DarwinPlatformKind::TvOS:
-    case DarwinPlatformKind::TvOSSimulator:
-      return "AppleTV";
-    case DarwinPlatformKind::WatchOS:
-    case DarwinPlatformKind::WatchOSSimulator:
-      return "Watch";
-  }
-  llvm_unreachable("Unsupported platform");
-}
-
-StringRef Darwin::getSDKName(StringRef isysroot) {
-  // Assume SDK has path: SOME_PATH/SDKs/PlatformXX.YY.sdk
-  llvm::sys::path::const_iterator SDKDir;
-  auto BeginSDK = llvm::sys::path::begin(isysroot);
-  auto EndSDK = llvm::sys::path::end(isysroot);
-  for (auto IT = BeginSDK; IT != EndSDK; ++IT) {
-    StringRef SDK = *IT;
-    if (SDK.endswith(".sdk"))
-      return SDK.slice(0, SDK.size() - 4);
-  }
-  return "";
-}
-
-StringRef Darwin::getOSLibraryNameSuffix() const {
-  switch(TargetPlatform) {
-  case DarwinPlatformKind::MacOS:
-    return "osx";
-  case DarwinPlatformKind::IPhoneOS:
-    return "ios";
-  case DarwinPlatformKind::IPhoneOSSimulator:
-    return "iossim";
-  case DarwinPlatformKind::TvOS:
-    return "tvos";
-  case DarwinPlatformKind::TvOSSimulator:
-    return "tvossim";
-  case DarwinPlatformKind::WatchOS:
-    return "watchos";
-  case DarwinPlatformKind::WatchOSSimulator:
-    return "watchossim";
-  }
-  llvm_unreachable("Unsupported platform");
-}
-
-void Darwin::addProfileRTLibs(const ArgList &Args,
-                              ArgStringList &CmdArgs) const {
-  if (!needsProfileRT(Args)) return;
-
-  AddLinkRuntimeLib(Args, CmdArgs, (Twine("libclang_rt.profile_") +
-       getOSLibraryNameSuffix() + ".a").str(),
-                    /*AlwaysLink*/ true);
-}
-
-void DarwinClang::AddLinkSanitizerLibArgs(const ArgList &Args,
-                                          ArgStringList &CmdArgs,
-                                          StringRef Sanitizer) const {
-  AddLinkRuntimeLib(
-      Args, CmdArgs,
-      (Twine("libclang_rt.") + Sanitizer + "_" +
-       getOSLibraryNameSuffix() + "_dynamic.dylib").str(),
-      /*AlwaysLink*/ true, /*IsEmbedded*/ false,
-      /*AddRPath*/ true);
-}
-
-ToolChain::RuntimeLibType DarwinClang::GetRuntimeLibType(
-    const ArgList &Args) const {
-  if (Arg* A = Args.getLastArg(options::OPT_rtlib_EQ)) {
-    StringRef Value = A->getValue();
-    if (Value != "compiler-rt")
-      getDriver().Diag(diag::err_drv_unsupported_rtlib_for_platform)
-          << Value << "darwin";
-  }
-
-  return ToolChain::RLT_CompilerRT;
-}
-
-void DarwinClang::AddLinkRuntimeLibArgs(const ArgList &Args,
-                                        ArgStringList &CmdArgs) const {
-  // Call once to ensure diagnostic is printed if wrong value was specified
-  GetRuntimeLibType(Args);
-
-  // Darwin doesn't support real static executables, don't link any runtime
-  // libraries with -static.
-  if (Args.hasArg(options::OPT_static) ||
-      Args.hasArg(options::OPT_fapple_kext) ||
-      Args.hasArg(options::OPT_mkernel))
-    return;
-
-  // Reject -static-libgcc for now, we can deal with this when and if someone
-  // cares. This is useful in situations where someone wants to statically link
-  // something like libstdc++, and needs its runtime support routines.
-  if (const Arg *A = Args.getLastArg(options::OPT_static_libgcc)) {
-    getDriver().Diag(diag::err_drv_unsupported_opt) << A->getAsString(Args);
-    return;
-  }
-
-  const SanitizerArgs &Sanitize = getSanitizerArgs();
-  if (Sanitize.needsAsanRt())
-    AddLinkSanitizerLibArgs(Args, CmdArgs, "asan");
-  if (Sanitize.needsUbsanRt())
-    AddLinkSanitizerLibArgs(Args, CmdArgs, "ubsan");
-  if (Sanitize.needsTsanRt())
-    AddLinkSanitizerLibArgs(Args, CmdArgs, "tsan");
-  if (Sanitize.needsStatsRt()) {
-    StringRef OS = isTargetMacOS() ? "osx" : "iossim";
-    AddLinkRuntimeLib(Args, CmdArgs,
-                      (Twine("libclang_rt.stats_client_") + OS + ".a").str(),
-                      /*AlwaysLink=*/true);
-    AddLinkSanitizerLibArgs(Args, CmdArgs, "stats");
-  }
-  if (Sanitize.needsEsanRt())
-    AddLinkSanitizerLibArgs(Args, CmdArgs, "esan");
-
-  // Otherwise link libSystem, then the dynamic runtime library, and finally any
-  // target specific static runtime library.
-  CmdArgs.push_back("-lSystem");
-
-  // Select the dynamic runtime library and the target specific static library.
-  if (isTargetWatchOSBased()) {
-    // We currently always need a static runtime library for watchOS.
-    AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.watchos.a");
-  } else if (isTargetTvOSBased()) {
-    // We currently always need a static runtime library for tvOS.
-    AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.tvos.a");
-  } else if (isTargetIOSBased()) {
-    // If we are compiling as iOS / simulator, don't attempt to link libgcc_s.1,
-    // it never went into the SDK.
-    // Linking against libgcc_s.1 isn't needed for iOS 5.0+
-    if (isIPhoneOSVersionLT(5, 0) && !isTargetIOSSimulator() &&
-        getTriple().getArch() != llvm::Triple::aarch64)
-      CmdArgs.push_back("-lgcc_s.1");
-
-    // We currently always need a static runtime library for iOS.
-    AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.ios.a");
-  } else {
-    assert(isTargetMacOS() && "unexpected non MacOS platform");
-    // The dynamic runtime library was merged with libSystem for 10.6 and
-    // beyond; only 10.4 and 10.5 need an additional runtime library.
-    if (isMacosxVersionLT(10, 5))
-      CmdArgs.push_back("-lgcc_s.10.4");
-    else if (isMacosxVersionLT(10, 6))
-      CmdArgs.push_back("-lgcc_s.10.5");
-
-    // Originally for OS X, we thought we would only need a static runtime
-    // library when targeting 10.4, to provide versions of the static functions
-    // which were omitted from 10.4.dylib. This led to the creation of the 10.4
-    // builtins library.
-    //
-    // Unfortunately, that turned out to not be true, because Darwin system
-    // headers can still use eprintf on i386, and it is not exported from
-    // libSystem. Therefore, we still must provide a runtime library just for
-    // the tiny tiny handful of projects that *might* use that symbol.
-    //
-    // Then over time, we figured out it was useful to add more things to the
-    // runtime so we created libclang_rt.osx.a to provide new functions when
-    // deploying to old OS builds, and for a long time we had both eprintf and
-    // osx builtin libraries. Which just seems excessive. So with PR 28855, we
-    // are removing the eprintf library and expecting eprintf to be provided by
-    // the OS X builtins library.
-    if (isMacosxVersionLT(10, 5))
-      AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.10.4.a");
-    else
-      AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.osx.a");
-  }
-}
-
-void Darwin::AddDeploymentTarget(DerivedArgList &Args) const {
-  const OptTable &Opts = getDriver().getOpts();
-
-  // Support allowing the SDKROOT environment variable used by xcrun and other
-  // Xcode tools to define the default sysroot, by making it the default for
-  // isysroot.
-  if (const Arg *A = Args.getLastArg(options::OPT_isysroot)) {
-    // Warn if the path does not exist.
-    if (!getVFS().exists(A->getValue()))
-      getDriver().Diag(clang::diag::warn_missing_sysroot) << A->getValue();
-  } else {
-    if (char *env = ::getenv("SDKROOT")) {
-      // We only use this value as the default if it is an absolute path,
-      // exists, and it is not the root path.
-      if (llvm::sys::path::is_absolute(env) && getVFS().exists(env) &&
-          StringRef(env) != "/") {
-        Args.append(Args.MakeSeparateArg(
-            nullptr, Opts.getOption(options::OPT_isysroot), env));
-      }
-    }
-  }
-
-  Arg *OSXVersion = Args.getLastArg(options::OPT_mmacosx_version_min_EQ);
-  Arg *iOSVersion = Args.getLastArg(options::OPT_miphoneos_version_min_EQ);
-  Arg *TvOSVersion = Args.getLastArg(options::OPT_mtvos_version_min_EQ);
-  Arg *WatchOSVersion = Args.getLastArg(options::OPT_mwatchos_version_min_EQ);
-
-  if (OSXVersion && (iOSVersion || TvOSVersion || WatchOSVersion)) {
-    getDriver().Diag(diag::err_drv_argument_not_allowed_with)
-        << OSXVersion->getAsString(Args)
-        << (iOSVersion ? iOSVersion :
-            TvOSVersion ? TvOSVersion : WatchOSVersion)->getAsString(Args);
-    iOSVersion = TvOSVersion = WatchOSVersion = nullptr;
-  } else if (iOSVersion && (TvOSVersion || WatchOSVersion)) {
-    getDriver().Diag(diag::err_drv_argument_not_allowed_with)
-        << iOSVersion->getAsString(Args)
-        << (TvOSVersion ? TvOSVersion : WatchOSVersion)->getAsString(Args);
-    TvOSVersion = WatchOSVersion = nullptr;
-  } else if (TvOSVersion && WatchOSVersion) {
-     getDriver().Diag(diag::err_drv_argument_not_allowed_with)
-        << TvOSVersion->getAsString(Args)
-        << WatchOSVersion->getAsString(Args);
-    WatchOSVersion = nullptr;
-  } else if (!OSXVersion && !iOSVersion && !TvOSVersion && !WatchOSVersion) {
-    // If no deployment target was specified on the command line, check for
-    // environment defines.
-    std::string OSXTarget;
-    std::string iOSTarget;
-    std::string TvOSTarget;
-    std::string WatchOSTarget;
-
-    if (char *env = ::getenv("MACOSX_DEPLOYMENT_TARGET"))
-      OSXTarget = env;
-    if (char *env = ::getenv("IPHONEOS_DEPLOYMENT_TARGET"))
-      iOSTarget = env;
-    if (char *env = ::getenv("TVOS_DEPLOYMENT_TARGET"))
-      TvOSTarget = env;
-    if (char *env = ::getenv("WATCHOS_DEPLOYMENT_TARGET"))
-      WatchOSTarget = env;
-
-    // If there is no command-line argument to specify the Target version and
-    // no environment variable defined, see if we can set the default based
-    // on -isysroot.
-    if (OSXTarget.empty() && iOSTarget.empty() && WatchOSTarget.empty() &&
-        TvOSTarget.empty() && Args.hasArg(options::OPT_isysroot)) {
-      if (const Arg *A = Args.getLastArg(options::OPT_isysroot)) {
-        StringRef isysroot = A->getValue();
-        StringRef SDK = getSDKName(isysroot);
-        if (SDK.size() > 0) {
-          // Slice the version number out.
-          // Version number is between the first and the last number.
-          size_t StartVer = SDK.find_first_of("0123456789");
-          size_t EndVer = SDK.find_last_of("0123456789");
-          if (StartVer != StringRef::npos && EndVer > StartVer) {
-            StringRef Version = SDK.slice(StartVer, EndVer + 1);
-            if (SDK.startswith("iPhoneOS") ||
-                SDK.startswith("iPhoneSimulator"))
-              iOSTarget = Version;
-            else if (SDK.startswith("MacOSX"))
-              OSXTarget = Version;
-            else if (SDK.startswith("WatchOS") ||
-                     SDK.startswith("WatchSimulator"))
-              WatchOSTarget = Version;
-            else if (SDK.startswith("AppleTVOS") ||
-                     SDK.startswith("AppleTVSimulator"))
-              TvOSTarget = Version;
-          }
-        }
-      }
-    }
-
-    // If no OSX or iOS target has been specified, try to guess platform
-    // from arch name and compute the version from the triple.
-    if (OSXTarget.empty() && iOSTarget.empty() && TvOSTarget.empty() &&
-        WatchOSTarget.empty()) {
-      StringRef MachOArchName = getMachOArchName(Args);
-      unsigned Major, Minor, Micro;
-      if (MachOArchName == "armv7" || MachOArchName == "armv7s" ||
-          MachOArchName == "arm64") {
-        getTriple().getiOSVersion(Major, Minor, Micro);
-        llvm::raw_string_ostream(iOSTarget) << Major << '.' << Minor << '.'
-                                            << Micro;
-      } else if (MachOArchName == "armv7k") {
-        getTriple().getWatchOSVersion(Major, Minor, Micro);
-        llvm::raw_string_ostream(WatchOSTarget) << Major << '.' << Minor << '.'
-                                                << Micro;
-      } else if (MachOArchName != "armv6m" && MachOArchName != "armv7m" &&
-                 MachOArchName != "armv7em") {
-        if (!getTriple().getMacOSXVersion(Major, Minor, Micro)) {
-          getDriver().Diag(diag::err_drv_invalid_darwin_version)
-              << getTriple().getOSName();
-        }
-        llvm::raw_string_ostream(OSXTarget) << Major << '.' << Minor << '.'
-                                            << Micro;
-      }
-    }
-
-    // Do not allow conflicts with the watchOS target.
-    if (!WatchOSTarget.empty() && (!iOSTarget.empty() || !TvOSTarget.empty())) {
-      getDriver().Diag(diag::err_drv_conflicting_deployment_targets)
-        << "WATCHOS_DEPLOYMENT_TARGET"
-        << (!iOSTarget.empty() ? "IPHONEOS_DEPLOYMENT_TARGET" :
-            "TVOS_DEPLOYMENT_TARGET");
-    }
-
-    // Do not allow conflicts with the tvOS target.
-    if (!TvOSTarget.empty() && !iOSTarget.empty()) {
-      getDriver().Diag(diag::err_drv_conflicting_deployment_targets)
-        << "TVOS_DEPLOYMENT_TARGET"
-        << "IPHONEOS_DEPLOYMENT_TARGET";
-    }
-
-    // Allow conflicts among OSX and iOS for historical reasons, but choose the
-    // default platform.
-    if (!OSXTarget.empty() && (!iOSTarget.empty() ||
-                               !WatchOSTarget.empty() ||
-                               !TvOSTarget.empty())) {
-      if (getTriple().getArch() == llvm::Triple::arm ||
-          getTriple().getArch() == llvm::Triple::aarch64 ||
-          getTriple().getArch() == llvm::Triple::thumb)
-        OSXTarget = "";
-      else
-        iOSTarget = WatchOSTarget = TvOSTarget = "";
-    }
-
-    if (!OSXTarget.empty()) {
-      const Option O = Opts.getOption(options::OPT_mmacosx_version_min_EQ);
-      OSXVersion = Args.MakeJoinedArg(nullptr, O, OSXTarget);
-      Args.append(OSXVersion);
-    } else if (!iOSTarget.empty()) {
-      const Option O = Opts.getOption(options::OPT_miphoneos_version_min_EQ);
-      iOSVersion = Args.MakeJoinedArg(nullptr, O, iOSTarget);
-      Args.append(iOSVersion);
-    } else if (!TvOSTarget.empty()) {
-      const Option O = Opts.getOption(options::OPT_mtvos_version_min_EQ);
-      TvOSVersion = Args.MakeJoinedArg(nullptr, O, TvOSTarget);
-      Args.append(TvOSVersion);
-    } else if (!WatchOSTarget.empty()) {
-      const Option O = Opts.getOption(options::OPT_mwatchos_version_min_EQ);
-      WatchOSVersion = Args.MakeJoinedArg(nullptr, O, WatchOSTarget);
-      Args.append(WatchOSVersion);
-    }
-  }
-
-  DarwinPlatformKind Platform;
-  if (OSXVersion)
-    Platform = MacOS;
-  else if (iOSVersion)
-    Platform = IPhoneOS;
-  else if (TvOSVersion)
-    Platform = TvOS;
-  else if (WatchOSVersion)
-    Platform = WatchOS;
-  else
-    llvm_unreachable("Unable to infer Darwin variant");
-
-  // Set the tool chain target information.
-  unsigned Major, Minor, Micro;
-  bool HadExtra;
-  if (Platform == MacOS) {
-    assert((!iOSVersion && !TvOSVersion && !WatchOSVersion) &&
-           "Unknown target platform!");
-    if (!Driver::GetReleaseVersion(OSXVersion->getValue(), Major, Minor, Micro,
-                                   HadExtra) ||
-        HadExtra || Major != 10 || Minor >= 100 || Micro >= 100)
-      getDriver().Diag(diag::err_drv_invalid_version_number)
-          << OSXVersion->getAsString(Args);
-  } else if (Platform == IPhoneOS) {
-    assert(iOSVersion && "Unknown target platform!");
-    if (!Driver::GetReleaseVersion(iOSVersion->getValue(), Major, Minor, Micro,
-                                   HadExtra) ||
-        HadExtra || Major >= 100 || Minor >= 100 || Micro >= 100)
-      getDriver().Diag(diag::err_drv_invalid_version_number)
-          << iOSVersion->getAsString(Args);
-  } else if (Platform == TvOS) {
-    if (!Driver::GetReleaseVersion(TvOSVersion->getValue(), Major, Minor,
-                                   Micro, HadExtra) || HadExtra ||
-        Major >= 100 || Minor >= 100 || Micro >= 100)
-      getDriver().Diag(diag::err_drv_invalid_version_number)
-          << TvOSVersion->getAsString(Args);
-  } else if (Platform == WatchOS) {
-    if (!Driver::GetReleaseVersion(WatchOSVersion->getValue(), Major, Minor,
-                                   Micro, HadExtra) || HadExtra ||
-        Major >= 10 || Minor >= 100 || Micro >= 100)
-      getDriver().Diag(diag::err_drv_invalid_version_number)
-          << WatchOSVersion->getAsString(Args);
-  } else
-    llvm_unreachable("unknown kind of Darwin platform");
-
-  // Recognize iOS targets with an x86 architecture as the iOS simulator.
-  if (iOSVersion && (getTriple().getArch() == llvm::Triple::x86 ||
-                     getTriple().getArch() == llvm::Triple::x86_64))
-    Platform = IPhoneOSSimulator;
-  if (TvOSVersion && (getTriple().getArch() == llvm::Triple::x86 ||
-                      getTriple().getArch() == llvm::Triple::x86_64))
-    Platform = TvOSSimulator;
-  if (WatchOSVersion && (getTriple().getArch() == llvm::Triple::x86 ||
-                         getTriple().getArch() == llvm::Triple::x86_64))
-    Platform = WatchOSSimulator;
-
-  setTarget(Platform, Major, Minor, Micro);
-
-  if (const Arg *A = Args.getLastArg(options::OPT_isysroot)) {
-    StringRef SDK = getSDKName(A->getValue());
-    if (SDK.size() > 0) {
-      size_t StartVer = SDK.find_first_of("0123456789");
-      StringRef SDKName = SDK.slice(0, StartVer);
-      if (!SDKName.startswith(getPlatformFamily()))
-        getDriver().Diag(diag::warn_incompatible_sysroot)
-            << SDKName << getPlatformFamily();
-    }
-  }
-}
-
-void DarwinClang::AddCXXStdlibLibArgs(const ArgList &Args,
-                                      ArgStringList &CmdArgs) const {
-  CXXStdlibType Type = GetCXXStdlibType(Args);
-
-  switch (Type) {
-  case ToolChain::CST_Libcxx:
-    CmdArgs.push_back("-lc++");
-    break;
-
-  case ToolChain::CST_Libstdcxx:
-    // Unfortunately, -lstdc++ doesn't always exist in the standard search path;
-    // it was previously found in the gcc lib dir. However, for all the Darwin
-    // platforms we care about it was -lstdc++.6, so we search for that
-    // explicitly if we can't see an obvious -lstdc++ candidate.
-
-    // Check in the sysroot first.
-    if (const Arg *A = Args.getLastArg(options::OPT_isysroot)) {
-      SmallString<128> P(A->getValue());
-      llvm::sys::path::append(P, "usr", "lib", "libstdc++.dylib");
-
-      if (!getVFS().exists(P)) {
-        llvm::sys::path::remove_filename(P);
-        llvm::sys::path::append(P, "libstdc++.6.dylib");
-        if (getVFS().exists(P)) {
-          CmdArgs.push_back(Args.MakeArgString(P));
-          return;
-        }
-      }
-    }
-
-    // Otherwise, look in the root.
-    // FIXME: This should be removed someday when we don't have to care about
-    // 10.6 and earlier, where /usr/lib/libstdc++.dylib does not exist.
-    if (!getVFS().exists("/usr/lib/libstdc++.dylib") &&
-        getVFS().exists("/usr/lib/libstdc++.6.dylib")) {
-      CmdArgs.push_back("/usr/lib/libstdc++.6.dylib");
-      return;
-    }
-
-    // Otherwise, let the linker search.
-    CmdArgs.push_back("-lstdc++");
-    break;
-  }
-}
-
-void DarwinClang::AddCCKextLibArgs(const ArgList &Args,
-                                   ArgStringList &CmdArgs) const {
-  // For Darwin platforms, use the compiler-rt-based support library
-  // instead of the gcc-provided one (which is also incidentally
-  // only present in the gcc lib dir, which makes it hard to find).
-
-  SmallString<128> P(getDriver().ResourceDir);
-  llvm::sys::path::append(P, "lib", "darwin");
-
-  // Use the newer cc_kext for iOS ARM after 6.0.
-  if (isTargetWatchOS()) {
-    llvm::sys::path::append(P, "libclang_rt.cc_kext_watchos.a");
-  } else if (isTargetTvOS()) {
-    llvm::sys::path::append(P, "libclang_rt.cc_kext_tvos.a");
-  } else if (isTargetIPhoneOS()) {
-    llvm::sys::path::append(P, "libclang_rt.cc_kext_ios.a");
-  } else {
-    llvm::sys::path::append(P, "libclang_rt.cc_kext.a");
-  }
-
-  // For now, allow missing resource libraries to support developers who may
-  // not have compiler-rt checked out or integrated into their build.
-  if (getVFS().exists(P))
-    CmdArgs.push_back(Args.MakeArgString(P));
-}
-
-DerivedArgList *MachO::TranslateArgs(const DerivedArgList &Args,
-                                     StringRef BoundArch,
-                                     Action::OffloadKind) const {
-  DerivedArgList *DAL = new DerivedArgList(Args.getBaseArgs());
-  const OptTable &Opts = getDriver().getOpts();
-
-  // FIXME: We really want to get out of the tool chain level argument
-  // translation business, as it makes the driver functionality much
-  // more opaque. For now, we follow gcc closely solely for the
-  // purpose of easily achieving feature parity & testability. Once we
-  // have something that works, we should reevaluate each translation
-  // and try to push it down into tool specific logic.
-
-  for (Arg *A : Args) {
-    if (A->getOption().matches(options::OPT_Xarch__)) {
-      // Skip this argument unless the architecture matches either the toolchain
-      // triple arch, or the arch being bound.
-      llvm::Triple::ArchType XarchArch =
-          tools::darwin::getArchTypeForMachOArchName(A->getValue(0));
-      if (!(XarchArch == getArch() ||
-            (!BoundArch.empty() &&
-             XarchArch ==
-                 tools::darwin::getArchTypeForMachOArchName(BoundArch))))
-        continue;
-
-      Arg *OriginalArg = A;
-      unsigned Index = Args.getBaseArgs().MakeIndex(A->getValue(1));
-      unsigned Prev = Index;
-      std::unique_ptr<Arg> XarchArg(Opts.ParseOneArg(Args, Index));
-
-      // If the argument parsing failed or more than one argument was
-      // consumed, the -Xarch_ argument's parameter tried to consume
-      // extra arguments. Emit an error and ignore.
-      //
-      // We also want to disallow any options which would alter the
-      // driver behavior; that isn't going to work in our model. We
-      // use isDriverOption() as an approximation, although things
-      // like -O4 are going to slip through.
-      if (!XarchArg || Index > Prev + 1) {
-        getDriver().Diag(diag::err_drv_invalid_Xarch_argument_with_args)
-            << A->getAsString(Args);
-        continue;
-      } else if (XarchArg->getOption().hasFlag(options::DriverOption)) {
-        getDriver().Diag(diag::err_drv_invalid_Xarch_argument_isdriver)
-            << A->getAsString(Args);
-        continue;
-      }
-
-      XarchArg->setBaseArg(A);
-
-      A = XarchArg.release();
-      DAL->AddSynthesizedArg(A);
-
-      // Linker input arguments require custom handling. The problem is that we
-      // have already constructed the phase actions, so we can not treat them as
-      // "input arguments".
-      if (A->getOption().hasFlag(options::LinkerInput)) {
-        // Convert the argument into individual Zlinker_input_args.
-        for (const char *Value : A->getValues()) {
-          DAL->AddSeparateArg(
-              OriginalArg, Opts.getOption(options::OPT_Zlinker_input), Value);
-        }
-        continue;
-      }
-    }
-
-    // Sob. These is strictly gcc compatible for the time being. Apple
-    // gcc translates options twice, which means that self-expanding
-    // options add duplicates.
-    switch ((options::ID)A->getOption().getID()) {
-    default:
-      DAL->append(A);
-      break;
-
-    case options::OPT_mkernel:
-    case options::OPT_fapple_kext:
-      DAL->append(A);
-      DAL->AddFlagArg(A, Opts.getOption(options::OPT_static));
-      break;
-
-    case options::OPT_dependency_file:
-      DAL->AddSeparateArg(A, Opts.getOption(options::OPT_MF), A->getValue());
-      break;
-
-    case options::OPT_gfull:
-      DAL->AddFlagArg(A, Opts.getOption(options::OPT_g_Flag));
-      DAL->AddFlagArg(
-          A, Opts.getOption(options::OPT_fno_eliminate_unused_debug_symbols));
-      break;
-
-    case options::OPT_gused:
-      DAL->AddFlagArg(A, Opts.getOption(options::OPT_g_Flag));
-      DAL->AddFlagArg(
-          A, Opts.getOption(options::OPT_feliminate_unused_debug_symbols));
-      break;
-
-    case options::OPT_shared:
-      DAL->AddFlagArg(A, Opts.getOption(options::OPT_dynamiclib));
-      break;
-
-    case options::OPT_fconstant_cfstrings:
-      DAL->AddFlagArg(A, Opts.getOption(options::OPT_mconstant_cfstrings));
-      break;
-
-    case options::OPT_fno_constant_cfstrings:
-      DAL->AddFlagArg(A, Opts.getOption(options::OPT_mno_constant_cfstrings));
-      break;
-
-    case options::OPT_Wnonportable_cfstrings:
-      DAL->AddFlagArg(A,
-                      Opts.getOption(options::OPT_mwarn_nonportable_cfstrings));
-      break;
-
-    case options::OPT_Wno_nonportable_cfstrings:
-      DAL->AddFlagArg(
-          A, Opts.getOption(options::OPT_mno_warn_nonportable_cfstrings));
-      break;
-
-    case options::OPT_fpascal_strings:
-      DAL->AddFlagArg(A, Opts.getOption(options::OPT_mpascal_strings));
-      break;
-
-    case options::OPT_fno_pascal_strings:
-      DAL->AddFlagArg(A, Opts.getOption(options::OPT_mno_pascal_strings));
-      break;
-    }
-  }
-
-  if (getTriple().getArch() == llvm::Triple::x86 ||
-      getTriple().getArch() == llvm::Triple::x86_64)
-    if (!Args.hasArgNoClaim(options::OPT_mtune_EQ))
-      DAL->AddJoinedArg(nullptr, Opts.getOption(options::OPT_mtune_EQ),
-                        "core2");
-
-  // Add the arch options based on the particular spelling of -arch, to match
-  // how the driver driver works.
-  if (!BoundArch.empty()) {
-    StringRef Name = BoundArch;
-    const Option MCpu = Opts.getOption(options::OPT_mcpu_EQ);
-    const Option MArch = Opts.getOption(options::OPT_march_EQ);
-
-    // This code must be kept in sync with LLVM's getArchTypeForDarwinArch,
-    // which defines the list of which architectures we accept.
-    if (Name == "ppc")
-      ;
-    else if (Name == "ppc601")
-      DAL->AddJoinedArg(nullptr, MCpu, "601");
-    else if (Name == "ppc603")
-      DAL->AddJoinedArg(nullptr, MCpu, "603");
-    else if (Name == "ppc604")
-      DAL->AddJoinedArg(nullptr, MCpu, "604");
-    else if (Name == "ppc604e")
-      DAL->AddJoinedArg(nullptr, MCpu, "604e");
-    else if (Name == "ppc750")
-      DAL->AddJoinedArg(nullptr, MCpu, "750");
-    else if (Name == "ppc7400")
-      DAL->AddJoinedArg(nullptr, MCpu, "7400");
-    else if (Name == "ppc7450")
-      DAL->AddJoinedArg(nullptr, MCpu, "7450");
-    else if (Name == "ppc970")
-      DAL->AddJoinedArg(nullptr, MCpu, "970");
-
-    else if (Name == "ppc64" || Name == "ppc64le")
-      DAL->AddFlagArg(nullptr, Opts.getOption(options::OPT_m64));
-
-    else if (Name == "i386")
-      ;
-    else if (Name == "i486")
-      DAL->AddJoinedArg(nullptr, MArch, "i486");
-    else if (Name == "i586")
-      DAL->AddJoinedArg(nullptr, MArch, "i586");
-    else if (Name == "i686")
-      DAL->AddJoinedArg(nullptr, MArch, "i686");
-    else if (Name == "pentium")
-      DAL->AddJoinedArg(nullptr, MArch, "pentium");
-    else if (Name == "pentium2")
-      DAL->AddJoinedArg(nullptr, MArch, "pentium2");
-    else if (Name == "pentpro")
-      DAL->AddJoinedArg(nullptr, MArch, "pentiumpro");
-    else if (Name == "pentIIm3")
-      DAL->AddJoinedArg(nullptr, MArch, "pentium2");
-
-    else if (Name == "x86_64")
-      DAL->AddFlagArg(nullptr, Opts.getOption(options::OPT_m64));
-    else if (Name == "x86_64h") {
-      DAL->AddFlagArg(nullptr, Opts.getOption(options::OPT_m64));
-      DAL->AddJoinedArg(nullptr, MArch, "x86_64h");
-    }
-
-    else if (Name == "arm")
-      DAL->AddJoinedArg(nullptr, MArch, "armv4t");
-    else if (Name == "armv4t")
-      DAL->AddJoinedArg(nullptr, MArch, "armv4t");
-    else if (Name == "armv5")
-      DAL->AddJoinedArg(nullptr, MArch, "armv5tej");
-    else if (Name == "xscale")
-      DAL->AddJoinedArg(nullptr, MArch, "xscale");
-    else if (Name == "armv6")
-      DAL->AddJoinedArg(nullptr, MArch, "armv6k");
-    else if (Name == "armv6m")
-      DAL->AddJoinedArg(nullptr, MArch, "armv6m");
-    else if (Name == "armv7")
-      DAL->AddJoinedArg(nullptr, MArch, "armv7a");
-    else if (Name == "armv7em")
-      DAL->AddJoinedArg(nullptr, MArch, "armv7em");
-    else if (Name == "armv7k")
-      DAL->AddJoinedArg(nullptr, MArch, "armv7k");
-    else if (Name == "armv7m")
-      DAL->AddJoinedArg(nullptr, MArch, "armv7m");
-    else if (Name == "armv7s")
-      DAL->AddJoinedArg(nullptr, MArch, "armv7s");
-  }
-
-  return DAL;
-}
-
-void MachO::AddLinkRuntimeLibArgs(const ArgList &Args,
-                                  ArgStringList &CmdArgs) const {
-  // Embedded targets are simple at the moment, not supporting sanitizers and
-  // with different libraries for each member of the product { static, PIC } x
-  // { hard-float, soft-float }
-  llvm::SmallString<32> CompilerRT = StringRef("libclang_rt.");
-  CompilerRT +=
-      (tools::arm::getARMFloatABI(*this, Args) == tools::arm::FloatABI::Hard)
-          ? "hard"
-          : "soft";
-  CompilerRT += Args.hasArg(options::OPT_fPIC) ? "_pic.a" : "_static.a";
-
-  AddLinkRuntimeLib(Args, CmdArgs, CompilerRT, false, true);
-}
-
-DerivedArgList *
-Darwin::TranslateArgs(const DerivedArgList &Args, StringRef BoundArch,
-                      Action::OffloadKind DeviceOffloadKind) const {
-  // First get the generic Apple args, before moving onto Darwin-specific ones.
-  DerivedArgList *DAL =
-      MachO::TranslateArgs(Args, BoundArch, DeviceOffloadKind);
-  const OptTable &Opts = getDriver().getOpts();
-
-  // If no architecture is bound, none of the translations here are relevant.
-  if (BoundArch.empty())
-    return DAL;
-
-  // Add an explicit version min argument for the deployment target. We do this
-  // after argument translation because -Xarch_ arguments may add a version min
-  // argument.
-  AddDeploymentTarget(*DAL);
-
-  // For iOS 6, undo the translation to add -static for -mkernel/-fapple-kext.
-  // FIXME: It would be far better to avoid inserting those -static arguments,
-  // but we can't check the deployment target in the translation code until
-  // it is set here.
-  if (isTargetWatchOSBased() ||
-      (isTargetIOSBased() && !isIPhoneOSVersionLT(6, 0))) {
-    for (ArgList::iterator it = DAL->begin(), ie = DAL->end(); it != ie; ) {
-      Arg *A = *it;
-      ++it;
-      if (A->getOption().getID() != options::OPT_mkernel &&
-          A->getOption().getID() != options::OPT_fapple_kext)
-        continue;
-      assert(it != ie && "unexpected argument translation");
-      A = *it;
-      assert(A->getOption().getID() == options::OPT_static &&
-             "missing expected -static argument");
-      it = DAL->getArgs().erase(it);
-    }
-  }
-
-  if (!Args.getLastArg(options::OPT_stdlib_EQ) &&
-      GetCXXStdlibType(Args) == ToolChain::CST_Libcxx)
-    DAL->AddJoinedArg(nullptr, Opts.getOption(options::OPT_stdlib_EQ),
-                      "libc++");
-
-  // Validate the C++ standard library choice.
-  CXXStdlibType Type = GetCXXStdlibType(*DAL);
-  if (Type == ToolChain::CST_Libcxx) {
-    // Check whether the target provides libc++.
-    StringRef where;
-
-    // Complain about targeting iOS < 5.0 in any way.
-    if (isTargetIOSBased() && isIPhoneOSVersionLT(5, 0))
-      where = "iOS 5.0";
-
-    if (where != StringRef()) {
-      getDriver().Diag(clang::diag::err_drv_invalid_libcxx_deployment) << where;
-    }
-  }
-
-  auto Arch = tools::darwin::getArchTypeForMachOArchName(BoundArch);
-  if ((Arch == llvm::Triple::arm || Arch == llvm::Triple::thumb)) {
-    if (Args.hasFlag(options::OPT_fomit_frame_pointer,
-                     options::OPT_fno_omit_frame_pointer, false))
-      getDriver().Diag(clang::diag::warn_drv_unsupported_opt_for_target)
-          << "-fomit-frame-pointer" << BoundArch;
-    if (Args.hasFlag(options::OPT_momit_leaf_frame_pointer,
-                     options::OPT_mno_omit_leaf_frame_pointer, false))
-      getDriver().Diag(clang::diag::warn_drv_unsupported_opt_for_target)
-          << "-momit-leaf-frame-pointer" << BoundArch;
-  }
-
-  return DAL;
-}
-
-bool MachO::IsUnwindTablesDefault() const {
-  return getArch() == llvm::Triple::x86_64;
-}
-
-bool MachO::UseDwarfDebugFlags() const {
-  if (const char *S = ::getenv("RC_DEBUG_OPTIONS"))
-    return S[0] != '\0';
-  return false;
-}
-
-bool Darwin::UseSjLjExceptions(const ArgList &Args) const {
-  // Darwin uses SjLj exceptions on ARM.
-  if (getTriple().getArch() != llvm::Triple::arm &&
-      getTriple().getArch() != llvm::Triple::thumb)
-    return false;
-
-  // Only watchOS uses the new DWARF/Compact unwinding method.
-  llvm::Triple Triple(ComputeLLVMTriple(Args));
-  return !Triple.isWatchABI();
-}
-
-bool Darwin::SupportsEmbeddedBitcode() const {
-  assert(TargetInitialized && "Target not initialized!");
-  if (isTargetIPhoneOS() && isIPhoneOSVersionLT(6, 0))
-    return false;
-  return true;
-}
-
-bool MachO::isPICDefault() const { return true; }
-
-bool MachO::isPIEDefault() const { return false; }
-
-bool MachO::isPICDefaultForced() const {
-  return (getArch() == llvm::Triple::x86_64 ||
-          getArch() == llvm::Triple::aarch64);
-}
-
-bool MachO::SupportsProfiling() const {
-  // Profiling instrumentation is only supported on x86.
-  return getArch() == llvm::Triple::x86 || getArch() == llvm::Triple::x86_64;
-}
-
-void Darwin::addMinVersionArgs(const ArgList &Args,
-                               ArgStringList &CmdArgs) const {
-  VersionTuple TargetVersion = getTargetVersion();
-
-  if (isTargetWatchOS())
-    CmdArgs.push_back("-watchos_version_min");
-  else if (isTargetWatchOSSimulator())
-    CmdArgs.push_back("-watchos_simulator_version_min");
-  else if (isTargetTvOS())
-    CmdArgs.push_back("-tvos_version_min");
-  else if (isTargetTvOSSimulator())
-    CmdArgs.push_back("-tvos_simulator_version_min");
-  else if (isTargetIOSSimulator())
-    CmdArgs.push_back("-ios_simulator_version_min");
-  else if (isTargetIOSBased())
-    CmdArgs.push_back("-iphoneos_version_min");
-  else {
-    assert(isTargetMacOS() && "unexpected target");
-    CmdArgs.push_back("-macosx_version_min");
-  }
-
-  CmdArgs.push_back(Args.MakeArgString(TargetVersion.getAsString()));
-}
-
-void Darwin::addStartObjectFileArgs(const ArgList &Args,
-                                    ArgStringList &CmdArgs) const {
-  // Derived from startfile spec.
-  if (Args.hasArg(options::OPT_dynamiclib)) {
-    // Derived from darwin_dylib1 spec.
-    if (isTargetWatchOSBased()) {
-      ; // watchOS does not need dylib1.o.
-    } else if (isTargetIOSSimulator()) {
-      ; // iOS simulator does not need dylib1.o.
-    } else if (isTargetIPhoneOS()) {
-      if (isIPhoneOSVersionLT(3, 1))
-        CmdArgs.push_back("-ldylib1.o");
-    } else {
-      if (isMacosxVersionLT(10, 5))
-        CmdArgs.push_back("-ldylib1.o");
-      else if (isMacosxVersionLT(10, 6))
-        CmdArgs.push_back("-ldylib1.10.5.o");
-    }
-  } else {
-    if (Args.hasArg(options::OPT_bundle)) {
-      if (!Args.hasArg(options::OPT_static)) {
-        // Derived from darwin_bundle1 spec.
-        if (isTargetWatchOSBased()) {
-          ; // watchOS does not need bundle1.o.
-        } else if (isTargetIOSSimulator()) {
-          ; // iOS simulator does not need bundle1.o.
-        } else if (isTargetIPhoneOS()) {
-          if (isIPhoneOSVersionLT(3, 1))
-            CmdArgs.push_back("-lbundle1.o");
-        } else {
-          if (isMacosxVersionLT(10, 6))
-            CmdArgs.push_back("-lbundle1.o");
-        }
-      }
-    } else {
-      if (Args.hasArg(options::OPT_pg) && SupportsProfiling()) {
-        if (Args.hasArg(options::OPT_static) ||
-            Args.hasArg(options::OPT_object) ||
-            Args.hasArg(options::OPT_preload)) {
-          CmdArgs.push_back("-lgcrt0.o");
-        } else {
-          CmdArgs.push_back("-lgcrt1.o");
-
-          // darwin_crt2 spec is empty.
-        }
-        // By default on OS X 10.8 and later, we don't link with a crt1.o
-        // file and the linker knows to use _main as the entry point.  But,
-        // when compiling with -pg, we need to link with the gcrt1.o file,
-        // so pass the -no_new_main option to tell the linker to use the
-        // "start" symbol as the entry point.
-        if (isTargetMacOS() && !isMacosxVersionLT(10, 8))
-          CmdArgs.push_back("-no_new_main");
-      } else {
-        if (Args.hasArg(options::OPT_static) ||
-            Args.hasArg(options::OPT_object) ||
-            Args.hasArg(options::OPT_preload)) {
-          CmdArgs.push_back("-lcrt0.o");
-        } else {
-          // Derived from darwin_crt1 spec.
-          if (isTargetWatchOSBased()) {
-            ; // watchOS does not need crt1.o.
-          } else if (isTargetIOSSimulator()) {
-            ; // iOS simulator does not need crt1.o.
-          } else if (isTargetIPhoneOS()) {
-            if (getArch() == llvm::Triple::aarch64)
-              ; // iOS does not need any crt1 files for arm64
-            else if (isIPhoneOSVersionLT(3, 1))
-              CmdArgs.push_back("-lcrt1.o");
-            else if (isIPhoneOSVersionLT(6, 0))
-              CmdArgs.push_back("-lcrt1.3.1.o");
-          } else {
-            if (isMacosxVersionLT(10, 5))
-              CmdArgs.push_back("-lcrt1.o");
-            else if (isMacosxVersionLT(10, 6))
-              CmdArgs.push_back("-lcrt1.10.5.o");
-            else if (isMacosxVersionLT(10, 8))
-              CmdArgs.push_back("-lcrt1.10.6.o");
-
-            // darwin_crt2 spec is empty.
-          }
-        }
-      }
-    }
-  }
-
-  if (!isTargetIPhoneOS() && Args.hasArg(options::OPT_shared_libgcc) &&
-      !isTargetWatchOS() &&
-      isMacosxVersionLT(10, 5)) {
-    const char *Str = Args.MakeArgString(GetFilePath("crt3.o"));
-    CmdArgs.push_back(Str);
-  }
-}
-
-bool Darwin::SupportsObjCGC() const { return isTargetMacOS(); }
-
-void Darwin::CheckObjCARC() const {
-  if (isTargetIOSBased() || isTargetWatchOSBased() ||
-      (isTargetMacOS() && !isMacosxVersionLT(10, 6)))
-    return;
-  getDriver().Diag(diag::err_arc_unsupported_on_toolchain);
-}
-
-SanitizerMask Darwin::getSupportedSanitizers() const {
-  const bool IsX86_64 = getTriple().getArch() == llvm::Triple::x86_64;
-  SanitizerMask Res = ToolChain::getSupportedSanitizers();
-  Res |= SanitizerKind::Address;
-  if (isTargetMacOS()) {
-    if (!isMacosxVersionLT(10, 9))
-      Res |= SanitizerKind::Vptr;
-    Res |= SanitizerKind::SafeStack;
-    if (IsX86_64)
-      Res |= SanitizerKind::Thread;
-  } else if (isTargetIOSSimulator() || isTargetTvOSSimulator()) {
-    if (IsX86_64)
-      Res |= SanitizerKind::Thread;
-  }
-  return Res;
-}
-
-void Darwin::printVerboseInfo(raw_ostream &OS) const {
-  CudaInstallation.print(OS);
-}
-
-/// Generic_GCC - A tool chain using the 'gcc' command to perform
-/// all subcommands; this relies on gcc translating the majority of
-/// command line options.
-
-/// \brief Parse a GCCVersion object out of a string of text.
-///
-/// This is the primary means of forming GCCVersion objects.
-/*static*/
-Generic_GCC::GCCVersion Linux::GCCVersion::Parse(StringRef VersionText) {
-  const GCCVersion BadVersion = {VersionText.str(), -1, -1, -1, "", "", ""};
-  std::pair<StringRef, StringRef> First = VersionText.split('.');
-  std::pair<StringRef, StringRef> Second = First.second.split('.');
-
-  GCCVersion GoodVersion = {VersionText.str(), -1, -1, -1, "", "", ""};
-  if (First.first.getAsInteger(10, GoodVersion.Major) || GoodVersion.Major < 0)
-    return BadVersion;
-  GoodVersion.MajorStr = First.first.str();
-  if (First.second.empty())
-    return GoodVersion;
-  if (Second.first.getAsInteger(10, GoodVersion.Minor) || GoodVersion.Minor < 0)
-    return BadVersion;
-  GoodVersion.MinorStr = Second.first.str();
-
-  // First look for a number prefix and parse that if present. Otherwise just
-  // stash the entire patch string in the suffix, and leave the number
-  // unspecified. This covers versions strings such as:
-  //   5        (handled above)
-  //   4.4
-  //   4.4.0
-  //   4.4.x
-  //   4.4.2-rc4
-  //   4.4.x-patched
-  // And retains any patch number it finds.
-  StringRef PatchText = GoodVersion.PatchSuffix = Second.second.str();
-  if (!PatchText.empty()) {
-    if (size_t EndNumber = PatchText.find_first_not_of("0123456789")) {
-      // Try to parse the number and any suffix.
-      if (PatchText.slice(0, EndNumber).getAsInteger(10, GoodVersion.Patch) ||
-          GoodVersion.Patch < 0)
-        return BadVersion;
-      GoodVersion.PatchSuffix = PatchText.substr(EndNumber);
-    }
-  }
-
-  return GoodVersion;
-}
-
-/// \brief Less-than for GCCVersion, implementing a Strict Weak Ordering.
-bool Generic_GCC::GCCVersion::isOlderThan(int RHSMajor, int RHSMinor,
-                                          int RHSPatch,
-                                          StringRef RHSPatchSuffix) const {
-  if (Major != RHSMajor)
-    return Major < RHSMajor;
-  if (Minor != RHSMinor)
-    return Minor < RHSMinor;
-  if (Patch != RHSPatch) {
-    // Note that versions without a specified patch sort higher than those with
-    // a patch.
-    if (RHSPatch == -1)
-      return true;
-    if (Patch == -1)
-      return false;
-
-    // Otherwise just sort on the patch itself.
-    return Patch < RHSPatch;
-  }
-  if (PatchSuffix != RHSPatchSuffix) {
-    // Sort empty suffixes higher.
-    if (RHSPatchSuffix.empty())
-      return true;
-    if (PatchSuffix.empty())
-      return false;
-
-    // Provide a lexicographic sort to make this a total ordering.
-    return PatchSuffix < RHSPatchSuffix;
-  }
-
-  // The versions are equal.
-  return false;
-}
-
-static llvm::StringRef getGCCToolchainDir(const ArgList &Args) {
-  const Arg *A = Args.getLastArg(options::OPT_gcc_toolchain);
-  if (A)
-    return A->getValue();
-  return GCC_INSTALL_PREFIX;
-}
-
-/// \brief Initialize a GCCInstallationDetector from the driver.
-///
-/// This performs all of the autodetection and sets up the various paths.
-/// Once constructed, a GCCInstallationDetector is essentially immutable.
-///
-/// FIXME: We shouldn't need an explicit TargetTriple parameter here, and
-/// should instead pull the target out of the driver. This is currently
-/// necessary because the driver doesn't store the final version of the target
-/// triple.
-void Generic_GCC::GCCInstallationDetector::init(
-    const llvm::Triple &TargetTriple, const ArgList &Args,
-    ArrayRef<std::string> ExtraTripleAliases) {
-  llvm::Triple BiarchVariantTriple = TargetTriple.isArch32Bit()
-                                         ? TargetTriple.get64BitArchVariant()
-                                         : TargetTriple.get32BitArchVariant();
-  // The library directories which may contain GCC installations.
-  SmallVector<StringRef, 4> CandidateLibDirs, CandidateBiarchLibDirs;
-  // The compatible GCC triples for this particular architecture.
-  SmallVector<StringRef, 16> CandidateTripleAliases;
-  SmallVector<StringRef, 16> CandidateBiarchTripleAliases;
-  CollectLibDirsAndTriples(TargetTriple, BiarchVariantTriple, CandidateLibDirs,
-                           CandidateTripleAliases, CandidateBiarchLibDirs,
-                           CandidateBiarchTripleAliases);
-
-  // Compute the set of prefixes for our search.
-  SmallVector<std::string, 8> Prefixes(D.PrefixDirs.begin(),
-                                       D.PrefixDirs.end());
-
-  StringRef GCCToolchainDir = getGCCToolchainDir(Args);
-  if (GCCToolchainDir != "") {
-    if (GCCToolchainDir.back() == '/')
-      GCCToolchainDir = GCCToolchainDir.drop_back(); // remove the /
-
-    Prefixes.push_back(GCCToolchainDir);
-  } else {
-    // If we have a SysRoot, try that first.
-    if (!D.SysRoot.empty()) {
-      Prefixes.push_back(D.SysRoot);
-      Prefixes.push_back(D.SysRoot + "/usr");
-    }
-
-    // Then look for gcc installed alongside clang.
-    Prefixes.push_back(D.InstalledDir + "/..");
-
-    // Then look for distribution supplied gcc installations.
-    if (D.SysRoot.empty()) {
-      // Look for RHEL devtoolsets.
-      Prefixes.push_back("/opt/rh/devtoolset-4/root/usr");
-      Prefixes.push_back("/opt/rh/devtoolset-3/root/usr");
-      Prefixes.push_back("/opt/rh/devtoolset-2/root/usr");
-      Prefixes.push_back("/opt/rh/devtoolset-1.1/root/usr");
-      Prefixes.push_back("/opt/rh/devtoolset-1.0/root/usr");
-      // And finally in /usr.
-      Prefixes.push_back("/usr");
-    }
-  }
-
-  // Try to respect gcc-config on Gentoo. However, do that only
-  // if --gcc-toolchain is not provided or equal to the Gentoo install
-  // in /usr. This avoids accidentally enforcing the system GCC version
-  // when using a custom toolchain.
-  if (GCCToolchainDir == "" || GCCToolchainDir == D.SysRoot + "/usr") {
-    for (StringRef CandidateTriple : ExtraTripleAliases) {
-      if (ScanGentooGccConfig(TargetTriple, Args, CandidateTriple))
-        return;
-    }
-    for (StringRef CandidateTriple : CandidateTripleAliases) {
-      if (ScanGentooGccConfig(TargetTriple, Args, CandidateTriple))
-        return;
-    }
-    for (StringRef CandidateTriple : CandidateBiarchTripleAliases) {
-      if (ScanGentooGccConfig(TargetTriple, Args, CandidateTriple, true))
-        return;
-    }
-  }
-
-  // Loop over the various components which exist and select the best GCC
-  // installation available. GCC installs are ranked by version number.
-  Version = GCCVersion::Parse("0.0.0");
-  for (const std::string &Prefix : Prefixes) {
-    if (!D.getVFS().exists(Prefix))
-      continue;
-    for (StringRef Suffix : CandidateLibDirs) {
-      const std::string LibDir = Prefix + Suffix.str();
-      if (!D.getVFS().exists(LibDir))
-        continue;
-      for (StringRef Candidate : ExtraTripleAliases) // Try these first.
-        ScanLibDirForGCCTriple(TargetTriple, Args, LibDir, Candidate);
-      for (StringRef Candidate : CandidateTripleAliases)
-        ScanLibDirForGCCTriple(TargetTriple, Args, LibDir, Candidate);
-    }
-    for (StringRef Suffix : CandidateBiarchLibDirs) {
-      const std::string LibDir = Prefix + Suffix.str();
-      if (!D.getVFS().exists(LibDir))
-        continue;
-      for (StringRef Candidate : CandidateBiarchTripleAliases)
-        ScanLibDirForGCCTriple(TargetTriple, Args, LibDir, Candidate,
-                               /*NeedsBiarchSuffix=*/ true);
-    }
-  }
-}
-
-void Generic_GCC::GCCInstallationDetector::print(raw_ostream &OS) const {
-  for (const auto &InstallPath : CandidateGCCInstallPaths)
-    OS << "Found candidate GCC installation: " << InstallPath << "\n";
-
-  if (!GCCInstallPath.empty())
-    OS << "Selected GCC installation: " << GCCInstallPath << "\n";
-
-  for (const auto &Multilib : Multilibs)
-    OS << "Candidate multilib: " << Multilib << "\n";
-
-  if (Multilibs.size() != 0 || !SelectedMultilib.isDefault())
-    OS << "Selected multilib: " << SelectedMultilib << "\n";
-}
-
-bool Generic_GCC::GCCInstallationDetector::getBiarchSibling(Multilib &M) const {
-  if (BiarchSibling.hasValue()) {
-    M = BiarchSibling.getValue();
-    return true;
-  }
-  return false;
-}
-
-/*static*/ void Generic_GCC::GCCInstallationDetector::CollectLibDirsAndTriples(
-    const llvm::Triple &TargetTriple, const llvm::Triple &BiarchTriple,
-    SmallVectorImpl<StringRef> &LibDirs,
-    SmallVectorImpl<StringRef> &TripleAliases,
-    SmallVectorImpl<StringRef> &BiarchLibDirs,
-    SmallVectorImpl<StringRef> &BiarchTripleAliases) {
-  // Declare a bunch of static data sets that we'll select between below. These
-  // are specifically designed to always refer to string literals to avoid any
-  // lifetime or initialization issues.
-  static const char *const AArch64LibDirs[] = {"/lib64", "/lib"};
-  static const char *const AArch64Triples[] = {
-      "aarch64-none-linux-gnu", "aarch64-linux-gnu", "aarch64-linux-android",
-      "aarch64-redhat-linux", "aarch64-suse-linux"};
-  static const char *const AArch64beLibDirs[] = {"/lib"};
-  static const char *const AArch64beTriples[] = {"aarch64_be-none-linux-gnu",
-                                                 "aarch64_be-linux-gnu"};
-
-  static const char *const ARMLibDirs[] = {"/lib"};
-  static const char *const ARMTriples[] = {"arm-linux-gnueabi",
-                                           "arm-linux-androideabi"};
-  static const char *const ARMHFTriples[] = {"arm-linux-gnueabihf",
-                                             "armv7hl-redhat-linux-gnueabi"};
-  static const char *const ARMebLibDirs[] = {"/lib"};
-  static const char *const ARMebTriples[] = {"armeb-linux-gnueabi",
-                                             "armeb-linux-androideabi"};
-  static const char *const ARMebHFTriples[] = {
-      "armeb-linux-gnueabihf", "armebv7hl-redhat-linux-gnueabi"};
-
-  static const char *const X86_64LibDirs[] = {"/lib64", "/lib"};
-  static const char *const X86_64Triples[] = {
-      "x86_64-linux-gnu",       "x86_64-unknown-linux-gnu",
-      "x86_64-pc-linux-gnu",    "x86_64-redhat-linux6E",
-      "x86_64-redhat-linux",    "x86_64-suse-linux",
-      "x86_64-manbo-linux-gnu", "x86_64-linux-gnu",
-      "x86_64-slackware-linux", "x86_64-linux-android",
-      "x86_64-unknown-linux"};
-  static const char *const X32LibDirs[] = {"/libx32"};
-  static const char *const X86LibDirs[] = {"/lib32", "/lib"};
-  static const char *const X86Triples[] = {
-      "i686-linux-gnu",       "i686-pc-linux-gnu",     "i486-linux-gnu",
-      "i386-linux-gnu",       "i386-redhat-linux6E",   "i686-redhat-linux",
-      "i586-redhat-linux",    "i386-redhat-linux",     "i586-suse-linux",
-      "i486-slackware-linux", "i686-montavista-linux", "i686-linux-android",
-      "i586-linux-gnu"};
-
-  static const char *const MIPSLibDirs[] = {"/lib"};
-  static const char *const MIPSTriples[] = {"mips-linux-gnu", "mips-mti-linux",
-                                            "mips-mti-linux-gnu",
-                                            "mips-img-linux-gnu"};
-  static const char *const MIPSELLibDirs[] = {"/lib"};
-  static const char *const MIPSELTriples[] = {"mipsel-linux-gnu",
-                                              "mips-img-linux-gnu"};
-
-  static const char *const MIPS64LibDirs[] = {"/lib64", "/lib"};
-  static const char *const MIPS64Triples[] = {
-      "mips64-linux-gnu", "mips-mti-linux-gnu", "mips-img-linux-gnu",
-      "mips64-linux-gnuabi64"};
-  static const char *const MIPS64ELLibDirs[] = {"/lib64", "/lib"};
-  static const char *const MIPS64ELTriples[] = {
-      "mips64el-linux-gnu", "mips-mti-linux-gnu", "mips-img-linux-gnu",
-      "mips64el-linux-gnuabi64"};
-
-  static const char *const MIPSELAndroidLibDirs[] = {"/lib", "/libr2",
-                                                     "/libr6"};
-  static const char *const MIPSELAndroidTriples[] = {"mipsel-linux-android"};
-  static const char *const MIPS64ELAndroidLibDirs[] = {"/lib64", "/lib",
-                                                       "/libr2", "/libr6"};
-  static const char *const MIPS64ELAndroidTriples[] = {
-      "mips64el-linux-android"};
-
-  static const char *const PPCLibDirs[] = {"/lib32", "/lib"};
-  static const char *const PPCTriples[] = {
-      "powerpc-linux-gnu", "powerpc-unknown-linux-gnu", "powerpc-linux-gnuspe",
-      "powerpc-suse-linux", "powerpc-montavista-linuxspe"};
-  static const char *const PPC64LibDirs[] = {"/lib64", "/lib"};
-  static const char *const PPC64Triples[] = {
-      "powerpc64-linux-gnu", "powerpc64-unknown-linux-gnu",
-      "powerpc64-suse-linux", "ppc64-redhat-linux"};
-  static const char *const PPC64LELibDirs[] = {"/lib64", "/lib"};
-  static const char *const PPC64LETriples[] = {
-      "powerpc64le-linux-gnu", "powerpc64le-unknown-linux-gnu",
-      "powerpc64le-suse-linux", "ppc64le-redhat-linux"};
-
-  static const char *const SPARCv8LibDirs[] = {"/lib32", "/lib"};
-  static const char *const SPARCv8Triples[] = {"sparc-linux-gnu",
-                                               "sparcv8-linux-gnu"};
-  static const char *const SPARCv9LibDirs[] = {"/lib64", "/lib"};
-  static const char *const SPARCv9Triples[] = {"sparc64-linux-gnu",
-                                               "sparcv9-linux-gnu"};
-
-  static const char *const SystemZLibDirs[] = {"/lib64", "/lib"};
-  static const char *const SystemZTriples[] = {
-      "s390x-linux-gnu", "s390x-unknown-linux-gnu", "s390x-ibm-linux-gnu",
-      "s390x-suse-linux", "s390x-redhat-linux"};
-
-  // Solaris.
-  static const char *const SolarisSPARCLibDirs[] = {"/gcc"};
-  static const char *const SolarisSPARCTriples[] = {"sparc-sun-solaris2.11",
-                                                    "i386-pc-solaris2.11"};
-
-  using std::begin;
-  using std::end;
-
-  if (TargetTriple.getOS() == llvm::Triple::Solaris) {
-    LibDirs.append(begin(SolarisSPARCLibDirs), end(SolarisSPARCLibDirs));
-    TripleAliases.append(begin(SolarisSPARCTriples), end(SolarisSPARCTriples));
-    return;
-  }
-
-  switch (TargetTriple.getArch()) {
-  case llvm::Triple::aarch64:
-    LibDirs.append(begin(AArch64LibDirs), end(AArch64LibDirs));
-    TripleAliases.append(begin(AArch64Triples), end(AArch64Triples));
-    BiarchLibDirs.append(begin(AArch64LibDirs), end(AArch64LibDirs));
-    BiarchTripleAliases.append(begin(AArch64Triples), end(AArch64Triples));
-    break;
-  case llvm::Triple::aarch64_be:
-    LibDirs.append(begin(AArch64beLibDirs), end(AArch64beLibDirs));
-    TripleAliases.append(begin(AArch64beTriples), end(AArch64beTriples));
-    BiarchLibDirs.append(begin(AArch64beLibDirs), end(AArch64beLibDirs));
-    BiarchTripleAliases.append(begin(AArch64beTriples), end(AArch64beTriples));
-    break;
-  case llvm::Triple::arm:
-  case llvm::Triple::thumb:
-    LibDirs.append(begin(ARMLibDirs), end(ARMLibDirs));
-    if (TargetTriple.getEnvironment() == llvm::Triple::GNUEABIHF) {
-      TripleAliases.append(begin(ARMHFTriples), end(ARMHFTriples));
-    } else {
-      TripleAliases.append(begin(ARMTriples), end(ARMTriples));
-    }
-    break;
-  case llvm::Triple::armeb:
-  case llvm::Triple::thumbeb:
-    LibDirs.append(begin(ARMebLibDirs), end(ARMebLibDirs));
-    if (TargetTriple.getEnvironment() == llvm::Triple::GNUEABIHF) {
-      TripleAliases.append(begin(ARMebHFTriples), end(ARMebHFTriples));
-    } else {
-      TripleAliases.append(begin(ARMebTriples), end(ARMebTriples));
-    }
-    break;
-  case llvm::Triple::x86_64:
-    LibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
-    TripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
-    // x32 is always available when x86_64 is available, so adding it as
-    // secondary arch with x86_64 triples
-    if (TargetTriple.getEnvironment() == llvm::Triple::GNUX32) {
-      BiarchLibDirs.append(begin(X32LibDirs), end(X32LibDirs));
-      BiarchTripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
-    } else {
-      BiarchLibDirs.append(begin(X86LibDirs), end(X86LibDirs));
-      BiarchTripleAliases.append(begin(X86Triples), end(X86Triples));
-    }
-    break;
-  case llvm::Triple::x86:
-    LibDirs.append(begin(X86LibDirs), end(X86LibDirs));
-    // MCU toolchain is 32 bit only and its triple alias is TargetTriple
-    // itself, which will be appended below.
-    if (!TargetTriple.isOSIAMCU()) {
-      TripleAliases.append(begin(X86Triples), end(X86Triples));
-      BiarchLibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
-      BiarchTripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
-    }
-    break;
-  case llvm::Triple::mips:
-    LibDirs.append(begin(MIPSLibDirs), end(MIPSLibDirs));
-    TripleAliases.append(begin(MIPSTriples), end(MIPSTriples));
-    BiarchLibDirs.append(begin(MIPS64LibDirs), end(MIPS64LibDirs));
-    BiarchTripleAliases.append(begin(MIPS64Triples), end(MIPS64Triples));
-    break;
-  case llvm::Triple::mipsel:
-    if (TargetTriple.isAndroid()) {
-      LibDirs.append(begin(MIPSELAndroidLibDirs), end(MIPSELAndroidLibDirs));
-      TripleAliases.append(begin(MIPSELAndroidTriples),
-                           end(MIPSELAndroidTriples));
-      BiarchLibDirs.append(begin(MIPS64ELAndroidLibDirs),
-                           end(MIPS64ELAndroidLibDirs));
-      BiarchTripleAliases.append(begin(MIPS64ELAndroidTriples),
-                                 end(MIPS64ELAndroidTriples));
-
-    } else {
-      LibDirs.append(begin(MIPSELLibDirs), end(MIPSELLibDirs));
-      TripleAliases.append(begin(MIPSELTriples), end(MIPSELTriples));
-      TripleAliases.append(begin(MIPSTriples), end(MIPSTriples));
-      BiarchLibDirs.append(begin(MIPS64ELLibDirs), end(MIPS64ELLibDirs));
-      BiarchTripleAliases.append(begin(MIPS64ELTriples), end(MIPS64ELTriples));
-    }
-    break;
-  case llvm::Triple::mips64:
-    LibDirs.append(begin(MIPS64LibDirs), end(MIPS64LibDirs));
-    TripleAliases.append(begin(MIPS64Triples), end(MIPS64Triples));
-    BiarchLibDirs.append(begin(MIPSLibDirs), end(MIPSLibDirs));
-    BiarchTripleAliases.append(begin(MIPSTriples), end(MIPSTriples));
-    break;
-  case llvm::Triple::mips64el:
-    if (TargetTriple.isAndroid()) {
-      LibDirs.append(begin(MIPS64ELAndroidLibDirs),
-                     end(MIPS64ELAndroidLibDirs));
-      TripleAliases.append(begin(MIPS64ELAndroidTriples),
-                           end(MIPS64ELAndroidTriples));
-      BiarchLibDirs.append(begin(MIPSELAndroidLibDirs),
-                           end(MIPSELAndroidLibDirs));
-      BiarchTripleAliases.append(begin(MIPSELAndroidTriples),
-                                 end(MIPSELAndroidTriples));
-
-    } else {
-      LibDirs.append(begin(MIPS64ELLibDirs), end(MIPS64ELLibDirs));
-      TripleAliases.append(begin(MIPS64ELTriples), end(MIPS64ELTriples));
-      BiarchLibDirs.append(begin(MIPSELLibDirs), end(MIPSELLibDirs));
-      BiarchTripleAliases.append(begin(MIPSELTriples), end(MIPSELTriples));
-      BiarchTripleAliases.append(begin(MIPSTriples), end(MIPSTriples));
-    }
-    break;
-  case llvm::Triple::ppc:
-    LibDirs.append(begin(PPCLibDirs), end(PPCLibDirs));
-    TripleAliases.append(begin(PPCTriples), end(PPCTriples));
-    BiarchLibDirs.append(begin(PPC64LibDirs), end(PPC64LibDirs));
-    BiarchTripleAliases.append(begin(PPC64Triples), end(PPC64Triples));
-    break;
-  case llvm::Triple::ppc64:
-    LibDirs.append(begin(PPC64LibDirs), end(PPC64LibDirs));
-    TripleAliases.append(begin(PPC64Triples), end(PPC64Triples));
-    BiarchLibDirs.append(begin(PPCLibDirs), end(PPCLibDirs));
-    BiarchTripleAliases.append(begin(PPCTriples), end(PPCTriples));
-    break;
-  case llvm::Triple::ppc64le:
-    LibDirs.append(begin(PPC64LELibDirs), end(PPC64LELibDirs));
-    TripleAliases.append(begin(PPC64LETriples), end(PPC64LETriples));
-    break;
-  case llvm::Triple::sparc:
-  case llvm::Triple::sparcel:
-    LibDirs.append(begin(SPARCv8LibDirs), end(SPARCv8LibDirs));
-    TripleAliases.append(begin(SPARCv8Triples), end(SPARCv8Triples));
-    BiarchLibDirs.append(begin(SPARCv9LibDirs), end(SPARCv9LibDirs));
-    BiarchTripleAliases.append(begin(SPARCv9Triples), end(SPARCv9Triples));
-    break;
-  case llvm::Triple::sparcv9:
-    LibDirs.append(begin(SPARCv9LibDirs), end(SPARCv9LibDirs));
-    TripleAliases.append(begin(SPARCv9Triples), end(SPARCv9Triples));
-    BiarchLibDirs.append(begin(SPARCv8LibDirs), end(SPARCv8LibDirs));
-    BiarchTripleAliases.append(begin(SPARCv8Triples), end(SPARCv8Triples));
-    break;
-  case llvm::Triple::systemz:
-    LibDirs.append(begin(SystemZLibDirs), end(SystemZLibDirs));
-    TripleAliases.append(begin(SystemZTriples), end(SystemZTriples));
-    break;
-  default:
-    // By default, just rely on the standard lib directories and the original
-    // triple.
-    break;
-  }
-
-  // Always append the drivers target triple to the end, in case it doesn't
-  // match any of our aliases.
-  TripleAliases.push_back(TargetTriple.str());
-
-  // Also include the multiarch variant if it's different.
-  if (TargetTriple.str() != BiarchTriple.str())
-    BiarchTripleAliases.push_back(BiarchTriple.str());
-}
-
-// Parses the contents of version.txt in an CUDA installation.  It should
-// contain one line of the from e.g. "CUDA Version 7.5.2".
-static CudaVersion ParseCudaVersionFile(llvm::StringRef V) {
-  if (!V.startswith("CUDA Version "))
-    return CudaVersion::UNKNOWN;
-  V = V.substr(strlen("CUDA Version "));
-  int Major = -1, Minor = -1;
-  auto First = V.split('.');
-  auto Second = First.second.split('.');
-  if (First.first.getAsInteger(10, Major) ||
-      Second.first.getAsInteger(10, Minor))
-    return CudaVersion::UNKNOWN;
-
-  if (Major == 7 && Minor == 0) {
-    // This doesn't appear to ever happen -- version.txt doesn't exist in the
-    // CUDA 7 installs I've seen.  But no harm in checking.
-    return CudaVersion::CUDA_70;
-  }
-  if (Major == 7 && Minor == 5)
-    return CudaVersion::CUDA_75;
-  if (Major == 8 && Minor == 0)
-    return CudaVersion::CUDA_80;
-  return CudaVersion::UNKNOWN;
-}
-
-CudaInstallationDetector::CudaInstallationDetector(
-    const Driver &D, const llvm::Triple &HostTriple,
-    const llvm::opt::ArgList &Args)
-    : D(D) {
-  SmallVector<std::string, 4> CudaPathCandidates;
-
-  // In decreasing order so we prefer newer versions to older versions.
-  std::initializer_list<const char *> Versions = {"8.0", "7.5", "7.0"};
-
-  if (Args.hasArg(options::OPT_cuda_path_EQ)) {
-    CudaPathCandidates.push_back(
-        Args.getLastArgValue(options::OPT_cuda_path_EQ));
-  } else if (HostTriple.isOSWindows()) {
-    for (const char *Ver : Versions)
-      CudaPathCandidates.push_back(
-          D.SysRoot + "/Program Files/NVIDIA GPU Computing Toolkit/CUDA/v" +
-          Ver);
-  } else {
-    CudaPathCandidates.push_back(D.SysRoot + "/usr/local/cuda");
-    for (const char *Ver : Versions)
-      CudaPathCandidates.push_back(D.SysRoot + "/usr/local/cuda-" + Ver);
-  }
-
-  for (const auto &CudaPath : CudaPathCandidates) {
-    if (CudaPath.empty() || !D.getVFS().exists(CudaPath))
-      continue;
-
-    InstallPath = CudaPath;
-    BinPath = CudaPath + "/bin";
-    IncludePath = InstallPath + "/include";
-    LibDevicePath = InstallPath + "/nvvm/libdevice";
-
-    auto &FS = D.getVFS();
-    if (!(FS.exists(IncludePath) && FS.exists(BinPath) &&
-          FS.exists(LibDevicePath)))
-      continue;
-
-    // On Linux, we have both lib and lib64 directories, and we need to choose
-    // based on our triple.  On MacOS, we have only a lib directory.
-    //
-    // It's sufficient for our purposes to be flexible: If both lib and lib64
-    // exist, we choose whichever one matches our triple.  Otherwise, if only
-    // lib exists, we use it.
-    if (HostTriple.isArch64Bit() && FS.exists(InstallPath + "/lib64"))
-      LibPath = InstallPath + "/lib64";
-    else if (FS.exists(InstallPath + "/lib"))
-      LibPath = InstallPath + "/lib";
-    else
-      continue;
-
-    llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> VersionFile =
-        FS.getBufferForFile(InstallPath + "/version.txt");
-    if (!VersionFile) {
-      // CUDA 7.0 doesn't have a version.txt, so guess that's our version if
-      // version.txt isn't present.
-      Version = CudaVersion::CUDA_70;
-    } else {
-      Version = ParseCudaVersionFile((*VersionFile)->getBuffer());
-    }
-
-    std::error_code EC;
-    for (llvm::sys::fs::directory_iterator LI(LibDevicePath, EC), LE;
-         !EC && LI != LE; LI = LI.increment(EC)) {
-      StringRef FilePath = LI->path();
-      StringRef FileName = llvm::sys::path::filename(FilePath);
-      // Process all bitcode filenames that look like libdevice.compute_XX.YY.bc
-      const StringRef LibDeviceName = "libdevice.";
-      if (!(FileName.startswith(LibDeviceName) && FileName.endswith(".bc")))
-        continue;
-      StringRef GpuArch = FileName.slice(
-          LibDeviceName.size(), FileName.find('.', LibDeviceName.size()));
-      LibDeviceMap[GpuArch] = FilePath.str();
-      // Insert map entries for specifc devices with this compute
-      // capability. NVCC's choice of the libdevice library version is
-      // rather peculiar and depends on the CUDA version.
-      if (GpuArch == "compute_20") {
-        LibDeviceMap["sm_20"] = FilePath;
-        LibDeviceMap["sm_21"] = FilePath;
-        LibDeviceMap["sm_32"] = FilePath;
-      } else if (GpuArch == "compute_30") {
-        LibDeviceMap["sm_30"] = FilePath;
-        if (Version < CudaVersion::CUDA_80) {
-          LibDeviceMap["sm_50"] = FilePath;
-          LibDeviceMap["sm_52"] = FilePath;
-          LibDeviceMap["sm_53"] = FilePath;
-        }
-        LibDeviceMap["sm_60"] = FilePath;
-        LibDeviceMap["sm_61"] = FilePath;
-        LibDeviceMap["sm_62"] = FilePath;
-      } else if (GpuArch == "compute_35") {
-        LibDeviceMap["sm_35"] = FilePath;
-        LibDeviceMap["sm_37"] = FilePath;
-      } else if (GpuArch == "compute_50") {
-        if (Version >= CudaVersion::CUDA_80) {
-          LibDeviceMap["sm_50"] = FilePath;
-          LibDeviceMap["sm_52"] = FilePath;
-          LibDeviceMap["sm_53"] = FilePath;
-        }
-      }
-    }
-
-    IsValid = true;
-    break;
-  }
-}
-
-void CudaInstallationDetector::AddCudaIncludeArgs(
-    const ArgList &DriverArgs, ArgStringList &CC1Args) const {
-  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
-    // Add cuda_wrappers/* to our system include path.  This lets us wrap
-    // standard library headers.
-    SmallString<128> P(D.ResourceDir);
-    llvm::sys::path::append(P, "include");
-    llvm::sys::path::append(P, "cuda_wrappers");
-    CC1Args.push_back("-internal-isystem");
-    CC1Args.push_back(DriverArgs.MakeArgString(P));
-  }
-
-  if (DriverArgs.hasArg(options::OPT_nocudainc))
-    return;
-
-  if (!isValid()) {
-    D.Diag(diag::err_drv_no_cuda_installation);
-    return;
-  }
-
-  CC1Args.push_back("-internal-isystem");
-  CC1Args.push_back(DriverArgs.MakeArgString(getIncludePath()));
-  CC1Args.push_back("-include");
-  CC1Args.push_back("__clang_cuda_runtime_wrapper.h");
-}
-
-void CudaInstallationDetector::CheckCudaVersionSupportsArch(
-    CudaArch Arch) const {
-  if (Arch == CudaArch::UNKNOWN || Version == CudaVersion::UNKNOWN ||
-      ArchsWithVersionTooLowErrors.count(Arch) > 0)
-    return;
-
-  auto RequiredVersion = MinVersionForCudaArch(Arch);
-  if (Version < RequiredVersion) {
-    ArchsWithVersionTooLowErrors.insert(Arch);
-    D.Diag(diag::err_drv_cuda_version_too_low)
-        << InstallPath << CudaArchToString(Arch) << CudaVersionToString(Version)
-        << CudaVersionToString(RequiredVersion);
-  }
-}
-
-void CudaInstallationDetector::print(raw_ostream &OS) const {
-  if (isValid())
-    OS << "Found CUDA installation: " << InstallPath << ", version "
-       << CudaVersionToString(Version) << "\n";
-}
-
-namespace {
-// Filter to remove Multilibs that don't exist as a suffix to Path
-class FilterNonExistent {
-  StringRef Base, File;
-  vfs::FileSystem &VFS;
-
-public:
-  FilterNonExistent(StringRef Base, StringRef File, vfs::FileSystem &VFS)
-      : Base(Base), File(File), VFS(VFS) {}
-  bool operator()(const Multilib &M) {
-    return !VFS.exists(Base + M.gccSuffix() + File);
-  }
-};
-} // end anonymous namespace
-
-static void addMultilibFlag(bool Enabled, const char *const Flag,
-                            std::vector<std::string> &Flags) {
-  if (Enabled)
-    Flags.push_back(std::string("+") + Flag);
-  else
-    Flags.push_back(std::string("-") + Flag);
-}
-
-static bool isArmOrThumbArch(llvm::Triple::ArchType Arch) {
-  return Arch == llvm::Triple::arm || Arch == llvm::Triple::thumb;
-}
-
-static bool isMipsArch(llvm::Triple::ArchType Arch) {
-  return Arch == llvm::Triple::mips || Arch == llvm::Triple::mipsel ||
-         Arch == llvm::Triple::mips64 || Arch == llvm::Triple::mips64el;
-}
-
-static bool isMips32(llvm::Triple::ArchType Arch) {
-  return Arch == llvm::Triple::mips || Arch == llvm::Triple::mipsel;
-}
-
-static bool isMips64(llvm::Triple::ArchType Arch) {
-  return Arch == llvm::Triple::mips64 || Arch == llvm::Triple::mips64el;
-}
-
-static bool isMipsEL(llvm::Triple::ArchType Arch) {
-  return Arch == llvm::Triple::mipsel || Arch == llvm::Triple::mips64el;
-}
-
-static bool isMips16(const ArgList &Args) {
-  Arg *A = Args.getLastArg(options::OPT_mips16, options::OPT_mno_mips16);
-  return A && A->getOption().matches(options::OPT_mips16);
-}
-
-static bool isMicroMips(const ArgList &Args) {
-  Arg *A = Args.getLastArg(options::OPT_mmicromips, options::OPT_mno_micromips);
-  return A && A->getOption().matches(options::OPT_mmicromips);
-}
-
-namespace {
-struct DetectedMultilibs {
-  /// The set of multilibs that the detected installation supports.
-  MultilibSet Multilibs;
-
-  /// The primary multilib appropriate for the given flags.
-  Multilib SelectedMultilib;
-
-  /// On Biarch systems, this corresponds to the default multilib when
-  /// targeting the non-default multilib. Otherwise, it is empty.
-  llvm::Optional<Multilib> BiarchSibling;
-};
-} // end anonymous namespace
-
-static Multilib makeMultilib(StringRef commonSuffix) {
-  return Multilib(commonSuffix, commonSuffix, commonSuffix);
-}
-
-static bool findMipsCsMultilibs(const Multilib::flags_list &Flags,
-                                FilterNonExistent &NonExistent,
-                                DetectedMultilibs &Result) {
-  // Check for Code Sourcery toolchain multilibs
-  MultilibSet CSMipsMultilibs;
-  {
-    auto MArchMips16 = makeMultilib("/mips16").flag("+m32").flag("+mips16");
-
-    auto MArchMicroMips =
-        makeMultilib("/micromips").flag("+m32").flag("+mmicromips");
-
-    auto MArchDefault = makeMultilib("").flag("-mips16").flag("-mmicromips");
-
-    auto UCLibc = makeMultilib("/uclibc").flag("+muclibc");
-
-    auto SoftFloat = makeMultilib("/soft-float").flag("+msoft-float");
-
-    auto Nan2008 = makeMultilib("/nan2008").flag("+mnan=2008");
-
-    auto DefaultFloat =
-        makeMultilib("").flag("-msoft-float").flag("-mnan=2008");
-
-    auto BigEndian = makeMultilib("").flag("+EB").flag("-EL");
-
-    auto LittleEndian = makeMultilib("/el").flag("+EL").flag("-EB");
-
-    // Note that this one's osSuffix is ""
-    auto MAbi64 = makeMultilib("")
-                      .gccSuffix("/64")
-                      .includeSuffix("/64")
-                      .flag("+mabi=n64")
-                      .flag("-mabi=n32")
-                      .flag("-m32");
-
-    CSMipsMultilibs =
-        MultilibSet()
-            .Either(MArchMips16, MArchMicroMips, MArchDefault)
-            .Maybe(UCLibc)
-            .Either(SoftFloat, Nan2008, DefaultFloat)
-            .FilterOut("/micromips/nan2008")
-            .FilterOut("/mips16/nan2008")
-            .Either(BigEndian, LittleEndian)
-            .Maybe(MAbi64)
-            .FilterOut("/mips16.*/64")
-            .FilterOut("/micromips.*/64")
-            .FilterOut(NonExistent)
-            .setIncludeDirsCallback([](const Multilib &M) {
-              std::vector<std::string> Dirs({"/include"});
-              if (StringRef(M.includeSuffix()).startswith("/uclibc"))
-                Dirs.push_back(
-                    "/../../../../mips-linux-gnu/libc/uclibc/usr/include");
-              else
-                Dirs.push_back("/../../../../mips-linux-gnu/libc/usr/include");
-              return Dirs;
-            });
-  }
-
-  MultilibSet DebianMipsMultilibs;
-  {
-    Multilib MAbiN32 =
-        Multilib().gccSuffix("/n32").includeSuffix("/n32").flag("+mabi=n32");
-
-    Multilib M64 = Multilib()
-                       .gccSuffix("/64")
-                       .includeSuffix("/64")
-                       .flag("+m64")
-                       .flag("-m32")
-                       .flag("-mabi=n32");
-
-    Multilib M32 = Multilib().flag("-m64").flag("+m32").flag("-mabi=n32");
-
-    DebianMipsMultilibs =
-        MultilibSet().Either(M32, M64, MAbiN32).FilterOut(NonExistent);
-  }
-
-  // Sort candidates. Toolchain that best meets the directories tree goes first.
-  // Then select the first toolchains matches command line flags.
-  MultilibSet *Candidates[] = {&CSMipsMultilibs, &DebianMipsMultilibs};
-  if (CSMipsMultilibs.size() < DebianMipsMultilibs.size())
-    std::iter_swap(Candidates, Candidates + 1);
-  for (const MultilibSet *Candidate : Candidates) {
-    if (Candidate->select(Flags, Result.SelectedMultilib)) {
-      if (Candidate == &DebianMipsMultilibs)
-        Result.BiarchSibling = Multilib();
-      Result.Multilibs = *Candidate;
-      return true;
-    }
-  }
-  return false;
-}
-
-static bool findMipsAndroidMultilibs(vfs::FileSystem &VFS, StringRef Path,
-                                     const Multilib::flags_list &Flags,
-                                     FilterNonExistent &NonExistent,
-                                     DetectedMultilibs &Result) {
-
-  MultilibSet AndroidMipsMultilibs =
-      MultilibSet()
-          .Maybe(Multilib("/mips-r2").flag("+march=mips32r2"))
-          .Maybe(Multilib("/mips-r6").flag("+march=mips32r6"))
-          .FilterOut(NonExistent);
-
-  MultilibSet AndroidMipselMultilibs =
-      MultilibSet()
-          .Either(Multilib().flag("+march=mips32"),
-                  Multilib("/mips-r2", "", "/mips-r2").flag("+march=mips32r2"),
-                  Multilib("/mips-r6", "", "/mips-r6").flag("+march=mips32r6"))
-          .FilterOut(NonExistent);
-
-  MultilibSet AndroidMips64elMultilibs =
-      MultilibSet()
-          .Either(
-              Multilib().flag("+march=mips64r6"),
-              Multilib("/32/mips-r1", "", "/mips-r1").flag("+march=mips32"),
-              Multilib("/32/mips-r2", "", "/mips-r2").flag("+march=mips32r2"),
-              Multilib("/32/mips-r6", "", "/mips-r6").flag("+march=mips32r6"))
-          .FilterOut(NonExistent);
-
-  MultilibSet *MS = &AndroidMipsMultilibs;
-  if (VFS.exists(Path + "/mips-r6"))
-    MS = &AndroidMipselMultilibs;
-  else if (VFS.exists(Path + "/32"))
-    MS = &AndroidMips64elMultilibs;
-  if (MS->select(Flags, Result.SelectedMultilib)) {
-    Result.Multilibs = *MS;
-    return true;
-  }
-  return false;
-}
-
-static bool findMipsMuslMultilibs(const Multilib::flags_list &Flags,
-                                  FilterNonExistent &NonExistent,
-                                  DetectedMultilibs &Result) {
-  // Musl toolchain multilibs
-  MultilibSet MuslMipsMultilibs;
-  {
-    auto MArchMipsR2 = makeMultilib("")
-                           .osSuffix("/mips-r2-hard-musl")
-                           .flag("+EB")
-                           .flag("-EL")
-                           .flag("+march=mips32r2");
-
-    auto MArchMipselR2 = makeMultilib("/mipsel-r2-hard-musl")
-                             .flag("-EB")
-                             .flag("+EL")
-                             .flag("+march=mips32r2");
-
-    MuslMipsMultilibs = MultilibSet().Either(MArchMipsR2, MArchMipselR2);
-
-    // Specify the callback that computes the include directories.
-    MuslMipsMultilibs.setIncludeDirsCallback([](const Multilib &M) {
-      return std::vector<std::string>(
-          {"/../sysroot" + M.osSuffix() + "/usr/include"});
-    });
-  }
-  if (MuslMipsMultilibs.select(Flags, Result.SelectedMultilib)) {
-    Result.Multilibs = MuslMipsMultilibs;
-    return true;
-  }
-  return false;
-}
-
-static bool findMipsMtiMultilibs(const Multilib::flags_list &Flags,
-                                 FilterNonExistent &NonExistent,
-                                 DetectedMultilibs &Result) {
-  // CodeScape MTI toolchain v1.2 and early.
-  MultilibSet MtiMipsMultilibsV1;
-  {
-    auto MArchMips32 = makeMultilib("/mips32")
-                           .flag("+m32")
-                           .flag("-m64")
-                           .flag("-mmicromips")
-                           .flag("+march=mips32");
-
-    auto MArchMicroMips = makeMultilib("/micromips")
-                              .flag("+m32")
-                              .flag("-m64")
-                              .flag("+mmicromips");
-
-    auto MArchMips64r2 = makeMultilib("/mips64r2")
-                             .flag("-m32")
-                             .flag("+m64")
-                             .flag("+march=mips64r2");
-
-    auto MArchMips64 = makeMultilib("/mips64").flag("-m32").flag("+m64").flag(
-        "-march=mips64r2");
-
-    auto MArchDefault = makeMultilib("")
-                            .flag("+m32")
-                            .flag("-m64")
-                            .flag("-mmicromips")
-                            .flag("+march=mips32r2");
-
-    auto Mips16 = makeMultilib("/mips16").flag("+mips16");
-
-    auto UCLibc = makeMultilib("/uclibc").flag("+muclibc");
-
-    auto MAbi64 =
-        makeMultilib("/64").flag("+mabi=n64").flag("-mabi=n32").flag("-m32");
-
-    auto BigEndian = makeMultilib("").flag("+EB").flag("-EL");
-
-    auto LittleEndian = makeMultilib("/el").flag("+EL").flag("-EB");
-
-    auto SoftFloat = makeMultilib("/sof").flag("+msoft-float");
-
-    auto Nan2008 = makeMultilib("/nan2008").flag("+mnan=2008");
-
-    MtiMipsMultilibsV1 =
-        MultilibSet()
-            .Either(MArchMips32, MArchMicroMips, MArchMips64r2, MArchMips64,
-                    MArchDefault)
-            .Maybe(UCLibc)
-            .Maybe(Mips16)
-            .FilterOut("/mips64/mips16")
-            .FilterOut("/mips64r2/mips16")
-            .FilterOut("/micromips/mips16")
-            .Maybe(MAbi64)
-            .FilterOut("/micromips/64")
-            .FilterOut("/mips32/64")
-            .FilterOut("^/64")
-            .FilterOut("/mips16/64")
-            .Either(BigEndian, LittleEndian)
-            .Maybe(SoftFloat)
-            .Maybe(Nan2008)
-            .FilterOut(".*sof/nan2008")
-            .FilterOut(NonExistent)
-            .setIncludeDirsCallback([](const Multilib &M) {
-              std::vector<std::string> Dirs({"/include"});
-              if (StringRef(M.includeSuffix()).startswith("/uclibc"))
-                Dirs.push_back("/../../../../sysroot/uclibc/usr/include");
-              else
-                Dirs.push_back("/../../../../sysroot/usr/include");
-              return Dirs;
-            });
-  }
-
-  // CodeScape IMG toolchain starting from v1.3.
-  MultilibSet MtiMipsMultilibsV2;
-  {
-    auto BeHard = makeMultilib("/mips-r2-hard")
-                      .flag("+EB")
-                      .flag("-msoft-float")
-                      .flag("-mnan=2008")
-                      .flag("-muclibc");
-    auto BeSoft = makeMultilib("/mips-r2-soft")
-                      .flag("+EB")
-                      .flag("+msoft-float")
-                      .flag("-mnan=2008");
-    auto ElHard = makeMultilib("/mipsel-r2-hard")
-                      .flag("+EL")
-                      .flag("-msoft-float")
-                      .flag("-mnan=2008")
-                      .flag("-muclibc");
-    auto ElSoft = makeMultilib("/mipsel-r2-soft")
-                      .flag("+EL")
-                      .flag("+msoft-float")
-                      .flag("-mnan=2008")
-                      .flag("-mmicromips");
-    auto BeHardNan = makeMultilib("/mips-r2-hard-nan2008")
-                         .flag("+EB")
-                         .flag("-msoft-float")
-                         .flag("+mnan=2008")
-                         .flag("-muclibc");
-    auto ElHardNan = makeMultilib("/mipsel-r2-hard-nan2008")
-                         .flag("+EL")
-                         .flag("-msoft-float")
-                         .flag("+mnan=2008")
-                         .flag("-muclibc")
-                         .flag("-mmicromips");
-    auto BeHardNanUclibc = makeMultilib("/mips-r2-hard-nan2008-uclibc")
-                               .flag("+EB")
-                               .flag("-msoft-float")
-                               .flag("+mnan=2008")
-                               .flag("+muclibc");
-    auto ElHardNanUclibc = makeMultilib("/mipsel-r2-hard-nan2008-uclibc")
-                               .flag("+EL")
-                               .flag("-msoft-float")
-                               .flag("+mnan=2008")
-                               .flag("+muclibc");
-    auto BeHardUclibc = makeMultilib("/mips-r2-hard-uclibc")
-                            .flag("+EB")
-                            .flag("-msoft-float")
-                            .flag("-mnan=2008")
-                            .flag("+muclibc");
-    auto ElHardUclibc = makeMultilib("/mipsel-r2-hard-uclibc")
-                            .flag("+EL")
-                            .flag("-msoft-float")
-                            .flag("-mnan=2008")
-                            .flag("+muclibc");
-    auto ElMicroHardNan = makeMultilib("/micromipsel-r2-hard-nan2008")
-                              .flag("+EL")
-                              .flag("-msoft-float")
-                              .flag("+mnan=2008")
-                              .flag("+mmicromips");
-    auto ElMicroSoft = makeMultilib("/micromipsel-r2-soft")
-                           .flag("+EL")
-                           .flag("+msoft-float")
-                           .flag("-mnan=2008")
-                           .flag("+mmicromips");
-
-    auto O32 =
-        makeMultilib("/lib").osSuffix("").flag("-mabi=n32").flag("-mabi=n64");
-    auto N32 =
-        makeMultilib("/lib32").osSuffix("").flag("+mabi=n32").flag("-mabi=n64");
-    auto N64 =
-        makeMultilib("/lib64").osSuffix("").flag("-mabi=n32").flag("+mabi=n64");
-
-    MtiMipsMultilibsV2 =
-        MultilibSet()
-            .Either({BeHard, BeSoft, ElHard, ElSoft, BeHardNan, ElHardNan,
-                     BeHardNanUclibc, ElHardNanUclibc, BeHardUclibc,
-                     ElHardUclibc, ElMicroHardNan, ElMicroSoft})
-            .Either(O32, N32, N64)
-            .FilterOut(NonExistent)
-            .setIncludeDirsCallback([](const Multilib &M) {
-              return std::vector<std::string>({"/../../../../sysroot" +
-                                               M.includeSuffix() +
-                                               "/../usr/include"});
-            })
-            .setFilePathsCallback([](const Multilib &M) {
-              return std::vector<std::string>(
-                  {"/../../../../mips-mti-linux-gnu/lib" + M.gccSuffix()});
-            });
-  }
-  for (auto Candidate : {&MtiMipsMultilibsV1, &MtiMipsMultilibsV2}) {
-    if (Candidate->select(Flags, Result.SelectedMultilib)) {
-      Result.Multilibs = *Candidate;
-      return true;
-    }
-  }
-  return false;
-}
-
-static bool findMipsImgMultilibs(const Multilib::flags_list &Flags,
-                                 FilterNonExistent &NonExistent,
-                                 DetectedMultilibs &Result) {
-  // CodeScape IMG toolchain v1.2 and early.
-  MultilibSet ImgMultilibsV1;
-  {
-    auto Mips64r6 = makeMultilib("/mips64r6").flag("+m64").flag("-m32");
-
-    auto LittleEndian = makeMultilib("/el").flag("+EL").flag("-EB");
-
-    auto MAbi64 =
-        makeMultilib("/64").flag("+mabi=n64").flag("-mabi=n32").flag("-m32");
-
-    ImgMultilibsV1 =
-        MultilibSet()
-            .Maybe(Mips64r6)
-            .Maybe(MAbi64)
-            .Maybe(LittleEndian)
-            .FilterOut(NonExistent)
-            .setIncludeDirsCallback([](const Multilib &M) {
-              return std::vector<std::string>(
-                  {"/include", "/../../../../sysroot/usr/include"});
-            });
-  }
-
-  // CodeScape IMG toolchain starting from v1.3.
-  MultilibSet ImgMultilibsV2;
-  {
-    auto BeHard = makeMultilib("/mips-r6-hard")
-                      .flag("+EB")
-                      .flag("-msoft-float")
-                      .flag("-mmicromips");
-    auto BeSoft = makeMultilib("/mips-r6-soft")
-                      .flag("+EB")
-                      .flag("+msoft-float")
-                      .flag("-mmicromips");
-    auto ElHard = makeMultilib("/mipsel-r6-hard")
-                      .flag("+EL")
-                      .flag("-msoft-float")
-                      .flag("-mmicromips");
-    auto ElSoft = makeMultilib("/mipsel-r6-soft")
-                      .flag("+EL")
-                      .flag("+msoft-float")
-                      .flag("-mmicromips");
-    auto BeMicroHard = makeMultilib("/micromips-r6-hard")
-                           .flag("+EB")
-                           .flag("-msoft-float")
-                           .flag("+mmicromips");
-    auto BeMicroSoft = makeMultilib("/micromips-r6-soft")
-                           .flag("+EB")
-                           .flag("+msoft-float")
-                           .flag("+mmicromips");
-    auto ElMicroHard = makeMultilib("/micromipsel-r6-hard")
-                           .flag("+EL")
-                           .flag("-msoft-float")
-                           .flag("+mmicromips");
-    auto ElMicroSoft = makeMultilib("/micromipsel-r6-soft")
-                           .flag("+EL")
-                           .flag("+msoft-float")
-                           .flag("+mmicromips");
-
-    auto O32 =
-        makeMultilib("/lib").osSuffix("").flag("-mabi=n32").flag("-mabi=n64");
-    auto N32 =
-        makeMultilib("/lib32").osSuffix("").flag("+mabi=n32").flag("-mabi=n64");
-    auto N64 =
-        makeMultilib("/lib64").osSuffix("").flag("-mabi=n32").flag("+mabi=n64");
-
-    ImgMultilibsV2 =
-        MultilibSet()
-            .Either({BeHard, BeSoft, ElHard, ElSoft, BeMicroHard, BeMicroSoft,
-                     ElMicroHard, ElMicroSoft})
-            .Either(O32, N32, N64)
-            .FilterOut(NonExistent)
-            .setIncludeDirsCallback([](const Multilib &M) {
-              return std::vector<std::string>({"/../../../../sysroot" +
-                                               M.includeSuffix() +
-                                               "/../usr/include"});
-            })
-            .setFilePathsCallback([](const Multilib &M) {
-              return std::vector<std::string>(
-                  {"/../../../../mips-img-linux-gnu/lib" + M.gccSuffix()});
-            });
-  }
-  for (auto Candidate : {&ImgMultilibsV1, &ImgMultilibsV2}) {
-    if (Candidate->select(Flags, Result.SelectedMultilib)) {
-      Result.Multilibs = *Candidate;
-      return true;
-    }
-  }
-  return false;
-}
-
-static bool findMIPSMultilibs(const Driver &D, const llvm::Triple &TargetTriple,
-                              StringRef Path, const ArgList &Args,
-                              DetectedMultilibs &Result) {
-  FilterNonExistent NonExistent(Path, "/crtbegin.o", D.getVFS());
-
-  StringRef CPUName;
-  StringRef ABIName;
-  tools::mips::getMipsCPUAndABI(Args, TargetTriple, CPUName, ABIName);
-
-  llvm::Triple::ArchType TargetArch = TargetTriple.getArch();
-
-  Multilib::flags_list Flags;
-  addMultilibFlag(isMips32(TargetArch), "m32", Flags);
-  addMultilibFlag(isMips64(TargetArch), "m64", Flags);
-  addMultilibFlag(isMips16(Args), "mips16", Flags);
-  addMultilibFlag(CPUName == "mips32", "march=mips32", Flags);
-  addMultilibFlag(CPUName == "mips32r2" || CPUName == "mips32r3" ||
-                      CPUName == "mips32r5" || CPUName == "p5600",
-                  "march=mips32r2", Flags);
-  addMultilibFlag(CPUName == "mips32r6", "march=mips32r6", Flags);
-  addMultilibFlag(CPUName == "mips64", "march=mips64", Flags);
-  addMultilibFlag(CPUName == "mips64r2" || CPUName == "mips64r3" ||
-                      CPUName == "mips64r5" || CPUName == "octeon",
-                  "march=mips64r2", Flags);
-  addMultilibFlag(CPUName == "mips64r6", "march=mips64r6", Flags);
-  addMultilibFlag(isMicroMips(Args), "mmicromips", Flags);
-  addMultilibFlag(tools::mips::isUCLibc(Args), "muclibc", Flags);
-  addMultilibFlag(tools::mips::isNaN2008(Args, TargetTriple), "mnan=2008",
-                  Flags);
-  addMultilibFlag(ABIName == "n32", "mabi=n32", Flags);
-  addMultilibFlag(ABIName == "n64", "mabi=n64", Flags);
-  addMultilibFlag(isSoftFloatABI(Args), "msoft-float", Flags);
-  addMultilibFlag(!isSoftFloatABI(Args), "mhard-float", Flags);
-  addMultilibFlag(isMipsEL(TargetArch), "EL", Flags);
-  addMultilibFlag(!isMipsEL(TargetArch), "EB", Flags);
-
-  if (TargetTriple.isAndroid())
-    return findMipsAndroidMultilibs(D.getVFS(), Path, Flags, NonExistent,
-                                    Result);
-
-  if (TargetTriple.getVendor() == llvm::Triple::MipsTechnologies &&
-      TargetTriple.getOS() == llvm::Triple::Linux &&
-      TargetTriple.getEnvironment() == llvm::Triple::UnknownEnvironment)
-    return findMipsMuslMultilibs(Flags, NonExistent, Result);
-
-  if (TargetTriple.getVendor() == llvm::Triple::MipsTechnologies &&
-      TargetTriple.getOS() == llvm::Triple::Linux &&
-      TargetTriple.getEnvironment() == llvm::Triple::GNU)
-    return findMipsMtiMultilibs(Flags, NonExistent, Result);
-
-  if (TargetTriple.getVendor() == llvm::Triple::ImaginationTechnologies &&
-      TargetTriple.getOS() == llvm::Triple::Linux &&
-      TargetTriple.getEnvironment() == llvm::Triple::GNU)
-    return findMipsImgMultilibs(Flags, NonExistent, Result);
-
-  if (findMipsCsMultilibs(Flags, NonExistent, Result))
-    return true;
-
-  // Fallback to the regular toolchain-tree structure.
-  Multilib Default;
-  Result.Multilibs.push_back(Default);
-  Result.Multilibs.FilterOut(NonExistent);
-
-  if (Result.Multilibs.select(Flags, Result.SelectedMultilib)) {
-    Result.BiarchSibling = Multilib();
-    return true;
-  }
-
-  return false;
-}
-
-static void findAndroidArmMultilibs(const Driver &D,
-                                    const llvm::Triple &TargetTriple,
-                                    StringRef Path, const ArgList &Args,
-                                    DetectedMultilibs &Result) {
-  // Find multilibs with subdirectories like armv7-a, thumb, armv7-a/thumb.
-  FilterNonExistent NonExistent(Path, "/crtbegin.o", D.getVFS());
-  Multilib ArmV7Multilib = makeMultilib("/armv7-a")
-                               .flag("+armv7")
-                               .flag("-thumb");
-  Multilib ThumbMultilib = makeMultilib("/thumb")
-                               .flag("-armv7")
-                               .flag("+thumb");
-  Multilib ArmV7ThumbMultilib = makeMultilib("/armv7-a/thumb")
-                               .flag("+armv7")
-                               .flag("+thumb");
-  Multilib DefaultMultilib = makeMultilib("")
-                               .flag("-armv7")
-                               .flag("-thumb");
-  MultilibSet AndroidArmMultilibs =
-      MultilibSet()
-          .Either(ThumbMultilib, ArmV7Multilib,
-                  ArmV7ThumbMultilib, DefaultMultilib)
-          .FilterOut(NonExistent);
-
-  Multilib::flags_list Flags;
-  llvm::StringRef Arch = Args.getLastArgValue(options::OPT_march_EQ);
-  bool IsArmArch = TargetTriple.getArch() == llvm::Triple::arm;
-  bool IsThumbArch = TargetTriple.getArch() == llvm::Triple::thumb;
-  bool IsV7SubArch = TargetTriple.getSubArch() == llvm::Triple::ARMSubArch_v7;
-  bool IsThumbMode = IsThumbArch ||
-      Args.hasFlag(options::OPT_mthumb, options::OPT_mno_thumb, false) ||
-      (IsArmArch && llvm::ARM::parseArchISA(Arch) == llvm::ARM::IK_THUMB);
-  bool IsArmV7Mode = (IsArmArch || IsThumbArch) &&
-      (llvm::ARM::parseArchVersion(Arch) == 7 ||
-       (IsArmArch && Arch == "" && IsV7SubArch));
-  addMultilibFlag(IsArmV7Mode, "armv7", Flags);
-  addMultilibFlag(IsThumbMode, "thumb", Flags);
-
-  if (AndroidArmMultilibs.select(Flags, Result.SelectedMultilib))
-    Result.Multilibs = AndroidArmMultilibs;
-}
-
-static bool findBiarchMultilibs(const Driver &D,
-                                const llvm::Triple &TargetTriple,
-                                StringRef Path, const ArgList &Args,
-                                bool NeedsBiarchSuffix,
-                                DetectedMultilibs &Result) {
-  // Some versions of SUSE and Fedora on ppc64 put 32-bit libs
-  // in what would normally be GCCInstallPath and put the 64-bit
-  // libs in a subdirectory named 64. The simple logic we follow is that
-  // *if* there is a subdirectory of the right name with crtbegin.o in it,
-  // we use that. If not, and if not a biarch triple alias, we look for
-  // crtbegin.o without the subdirectory.
-
-  Multilib Default;
-  Multilib Alt64 = Multilib()
-                       .gccSuffix("/64")
-                       .includeSuffix("/64")
-                       .flag("-m32")
-                       .flag("+m64")
-                       .flag("-mx32");
-  Multilib Alt32 = Multilib()
-                       .gccSuffix("/32")
-                       .includeSuffix("/32")
-                       .flag("+m32")
-                       .flag("-m64")
-                       .flag("-mx32");
-  Multilib Altx32 = Multilib()
-                        .gccSuffix("/x32")
-                        .includeSuffix("/x32")
-                        .flag("-m32")
-                        .flag("-m64")
-                        .flag("+mx32");
-
-  // GCC toolchain for IAMCU doesn't have crtbegin.o, so look for libgcc.a.
-  FilterNonExistent NonExistent(
-      Path, TargetTriple.isOSIAMCU() ? "/libgcc.a" : "/crtbegin.o", D.getVFS());
-
-  // Determine default multilib from: 32, 64, x32
-  // Also handle cases such as 64 on 32, 32 on 64, etc.
-  enum { UNKNOWN, WANT32, WANT64, WANTX32 } Want = UNKNOWN;
-  const bool IsX32 = TargetTriple.getEnvironment() == llvm::Triple::GNUX32;
-  if (TargetTriple.isArch32Bit() && !NonExistent(Alt32))
-    Want = WANT64;
-  else if (TargetTriple.isArch64Bit() && IsX32 && !NonExistent(Altx32))
-    Want = WANT64;
-  else if (TargetTriple.isArch64Bit() && !IsX32 && !NonExistent(Alt64))
-    Want = WANT32;
-  else {
-    if (TargetTriple.isArch32Bit())
-      Want = NeedsBiarchSuffix ? WANT64 : WANT32;
-    else if (IsX32)
-      Want = NeedsBiarchSuffix ? WANT64 : WANTX32;
-    else
-      Want = NeedsBiarchSuffix ? WANT32 : WANT64;
-  }
-
-  if (Want == WANT32)
-    Default.flag("+m32").flag("-m64").flag("-mx32");
-  else if (Want == WANT64)
-    Default.flag("-m32").flag("+m64").flag("-mx32");
-  else if (Want == WANTX32)
-    Default.flag("-m32").flag("-m64").flag("+mx32");
-  else
-    return false;
-
-  Result.Multilibs.push_back(Default);
-  Result.Multilibs.push_back(Alt64);
-  Result.Multilibs.push_back(Alt32);
-  Result.Multilibs.push_back(Altx32);
-
-  Result.Multilibs.FilterOut(NonExistent);
-
-  Multilib::flags_list Flags;
-  addMultilibFlag(TargetTriple.isArch64Bit() && !IsX32, "m64", Flags);
-  addMultilibFlag(TargetTriple.isArch32Bit(), "m32", Flags);
-  addMultilibFlag(TargetTriple.isArch64Bit() && IsX32, "mx32", Flags);
-
-  if (!Result.Multilibs.select(Flags, Result.SelectedMultilib))
-    return false;
-
-  if (Result.SelectedMultilib == Alt64 || Result.SelectedMultilib == Alt32 ||
-      Result.SelectedMultilib == Altx32)
-    Result.BiarchSibling = Default;
-
-  return true;
-}
-
-void Generic_GCC::GCCInstallationDetector::scanLibDirForGCCTripleSolaris(
-    const llvm::Triple &TargetArch, const llvm::opt::ArgList &Args,
-    const std::string &LibDir, StringRef CandidateTriple,
-    bool NeedsBiarchSuffix) {
-  // Solaris is a special case. The GCC installation is under
-  // /usr/gcc/<major>.<minor>/lib/gcc/<triple>/<major>.<minor>.<patch>/, so we
-  // need to iterate twice.
-  std::error_code EC;
-  for (vfs::directory_iterator LI = D.getVFS().dir_begin(LibDir, EC), LE;
-       !EC && LI != LE; LI = LI.increment(EC)) {
-    StringRef VersionText = llvm::sys::path::filename(LI->getName());
-    GCCVersion CandidateVersion = GCCVersion::Parse(VersionText);
-
-    if (CandidateVersion.Major != -1) // Filter obviously bad entries.
-      if (!CandidateGCCInstallPaths.insert(LI->getName()).second)
-        continue; // Saw this path before; no need to look at it again.
-    if (CandidateVersion.isOlderThan(4, 1, 1))
-      continue;
-    if (CandidateVersion <= Version)
-      continue;
-
-    GCCInstallPath =
-        LibDir + "/" + VersionText.str() + "/lib/gcc/" + CandidateTriple.str();
-    if (!D.getVFS().exists(GCCInstallPath))
-      continue;
-
-    // If we make it here there has to be at least one GCC version, let's just
-    // use the latest one.
-    std::error_code EEC;
-    for (vfs::directory_iterator
-             LLI = D.getVFS().dir_begin(GCCInstallPath, EEC),
-             LLE;
-         !EEC && LLI != LLE; LLI = LLI.increment(EEC)) {
-
-      StringRef SubVersionText = llvm::sys::path::filename(LLI->getName());
-      GCCVersion CandidateSubVersion = GCCVersion::Parse(SubVersionText);
-
-      if (CandidateSubVersion > Version)
-        Version = CandidateSubVersion;
-    }
-
-    GCCTriple.setTriple(CandidateTriple);
-
-    GCCInstallPath += "/" + Version.Text;
-    GCCParentLibPath = GCCInstallPath + "/../../../../";
-
-    IsValid = true;
-  }
-}
-
-bool Generic_GCC::GCCInstallationDetector::ScanGCCForMultilibs(
-    const llvm::Triple &TargetTriple, const ArgList &Args,
-    StringRef Path, bool NeedsBiarchSuffix) {
-  llvm::Triple::ArchType TargetArch = TargetTriple.getArch();
-  DetectedMultilibs Detected;
-
-  // Android standalone toolchain could have multilibs for ARM and Thumb.
-  // Debian mips multilibs behave more like the rest of the biarch ones,
-  // so handle them there
-  if (isArmOrThumbArch(TargetArch) && TargetTriple.isAndroid()) {
-    // It should also work without multilibs in a simplified toolchain.
-    findAndroidArmMultilibs(D, TargetTriple, Path, Args, Detected);
-  } else if (isMipsArch(TargetArch)) {
-    if (!findMIPSMultilibs(D, TargetTriple, Path, Args, Detected))
-      return false;
-  } else if (!findBiarchMultilibs(D, TargetTriple, Path, Args,
-                                  NeedsBiarchSuffix, Detected)) {
-    return false;
-  }
-
-  Multilibs = Detected.Multilibs;
-  SelectedMultilib = Detected.SelectedMultilib;
-  BiarchSibling = Detected.BiarchSibling;
-
-  return true;
-}
-
-void Generic_GCC::GCCInstallationDetector::ScanLibDirForGCCTriple(
-    const llvm::Triple &TargetTriple, const ArgList &Args,
-    const std::string &LibDir, StringRef CandidateTriple,
-    bool NeedsBiarchSuffix) {
-  llvm::Triple::ArchType TargetArch = TargetTriple.getArch();
-  // There are various different suffixes involving the triple we
-  // check for. We also record what is necessary to walk from each back
-  // up to the lib directory. Specifically, the number of "up" steps
-  // in the second half of each row is 1 + the number of path separators
-  // in the first half.
-  const std::string LibAndInstallSuffixes[][2] = {
-      {"/gcc/" + CandidateTriple.str(), "/../../.."},
-
-      // Debian puts cross-compilers in gcc-cross
-      {"/gcc-cross/" + CandidateTriple.str(), "/../../.."},
-
-      {"/" + CandidateTriple.str() + "/gcc/" + CandidateTriple.str(),
-       "/../../../.."},
-
-      // The Freescale PPC SDK has the gcc libraries in
-      // <sysroot>/usr/lib/<triple>/x.y.z so have a look there as well.
-      {"/" + CandidateTriple.str(), "/../.."},
-
-      // Ubuntu has a strange mis-matched pair of triples that this happens to
-      // match.
-      // FIXME: It may be worthwhile to generalize this and look for a second
-      // triple.
-      {"/i386-linux-gnu/gcc/" + CandidateTriple.str(), "/../../../.."}};
-
-  if (TargetTriple.getOS() == llvm::Triple::Solaris) {
-    scanLibDirForGCCTripleSolaris(TargetTriple, Args, LibDir, CandidateTriple,
-                                  NeedsBiarchSuffix);
-    return;
-  }
-
-  // Only look at the final, weird Ubuntu suffix for i386-linux-gnu.
-  const unsigned NumLibSuffixes = (llvm::array_lengthof(LibAndInstallSuffixes) -
-                                   (TargetArch != llvm::Triple::x86));
-  for (unsigned i = 0; i < NumLibSuffixes; ++i) {
-    StringRef LibSuffix = LibAndInstallSuffixes[i][0];
-    std::error_code EC;
-    for (vfs::directory_iterator
-             LI = D.getVFS().dir_begin(LibDir + LibSuffix, EC),
-             LE;
-         !EC && LI != LE; LI = LI.increment(EC)) {
-      StringRef VersionText = llvm::sys::path::filename(LI->getName());
-      GCCVersion CandidateVersion = GCCVersion::Parse(VersionText);
-      if (CandidateVersion.Major != -1) // Filter obviously bad entries.
-        if (!CandidateGCCInstallPaths.insert(LI->getName()).second)
-          continue; // Saw this path before; no need to look at it again.
-      if (CandidateVersion.isOlderThan(4, 1, 1))
-        continue;
-      if (CandidateVersion <= Version)
-        continue;
-
-      if (!ScanGCCForMultilibs(TargetTriple, Args, LI->getName(),
-                               NeedsBiarchSuffix))
-        continue;
-
-      Version = CandidateVersion;
-      GCCTriple.setTriple(CandidateTriple);
-      // FIXME: We hack together the directory name here instead of
-      // using LI to ensure stable path separators across Windows and
-      // Linux.
-      GCCInstallPath =
-          LibDir + LibAndInstallSuffixes[i][0] + "/" + VersionText.str();
-      GCCParentLibPath = GCCInstallPath + LibAndInstallSuffixes[i][1];
-      IsValid = true;
-    }
-  }
-}
-
-bool Generic_GCC::GCCInstallationDetector::ScanGentooGccConfig(
-    const llvm::Triple &TargetTriple, const ArgList &Args,
-    StringRef CandidateTriple, bool NeedsBiarchSuffix) {
-  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> File =
-      D.getVFS().getBufferForFile(D.SysRoot + "/etc/env.d/gcc/config-" +
-                                  CandidateTriple.str());
-  if (File) {
-    SmallVector<StringRef, 2> Lines;
-    File.get()->getBuffer().split(Lines, "\n");
-    for (StringRef Line : Lines) {
-      // CURRENT=triple-version
-      if (Line.consume_front("CURRENT=")) {
-        const std::pair<StringRef, StringRef> ActiveVersion =
-          Line.rsplit('-');
-        // Note: Strictly speaking, we should be reading
-        // /etc/env.d/gcc/${CURRENT} now. However, the file doesn't
-        // contain anything new or especially useful to us.
-        const std::string GentooPath = D.SysRoot + "/usr/lib/gcc/" +
-                                       ActiveVersion.first.str() + "/" +
-                                       ActiveVersion.second.str();
-        if (D.getVFS().exists(GentooPath + "/crtbegin.o")) {
-          if (!ScanGCCForMultilibs(TargetTriple, Args, GentooPath,
-                                   NeedsBiarchSuffix))
-            return false;
-
-          Version = GCCVersion::Parse(ActiveVersion.second);
-          GCCInstallPath = GentooPath;
-          GCCParentLibPath = GentooPath + "/../../..";
-          GCCTriple.setTriple(ActiveVersion.first);
-          IsValid = true;
-          return true;
-        }
-      }
-    }
-  }
-
-  return false;
-}
-
-Generic_GCC::Generic_GCC(const Driver &D, const llvm::Triple &Triple,
-                         const ArgList &Args)
-    : ToolChain(D, Triple, Args), GCCInstallation(D),
-      CudaInstallation(D, Triple, Args) {
-  getProgramPaths().push_back(getDriver().getInstalledDir());
-  if (getDriver().getInstalledDir() != getDriver().Dir)
-    getProgramPaths().push_back(getDriver().Dir);
-}
-
-Generic_GCC::~Generic_GCC() {}
-
-Tool *Generic_GCC::getTool(Action::ActionClass AC) const {
-  switch (AC) {
-  case Action::PreprocessJobClass:
-    if (!Preprocess)
-      Preprocess.reset(new tools::gcc::Preprocessor(*this));
-    return Preprocess.get();
-  case Action::CompileJobClass:
-    if (!Compile)
-      Compile.reset(new tools::gcc::Compiler(*this));
-    return Compile.get();
-  default:
-    return ToolChain::getTool(AC);
-  }
-}
-
-Tool *Generic_GCC::buildAssembler() const {
-  return new tools::gnutools::Assembler(*this);
-}
-
-Tool *Generic_GCC::buildLinker() const { return new tools::gcc::Linker(*this); }
-
-void Generic_GCC::printVerboseInfo(raw_ostream &OS) const {
-  // Print the information about how we detected the GCC installation.
-  GCCInstallation.print(OS);
-  CudaInstallation.print(OS);
-}
-
-bool Generic_GCC::IsUnwindTablesDefault() const {
-  return getArch() == llvm::Triple::x86_64;
-}
-
-bool Generic_GCC::isPICDefault() const {
-  switch (getArch()) {
-  case llvm::Triple::x86_64:
-    return getTriple().isOSWindows();
-  case llvm::Triple::ppc64:
-  case llvm::Triple::ppc64le:
-    return !getTriple().isOSBinFormatMachO() && !getTriple().isMacOSX();
-  default:
-    return false;
-  }
-}
-
-bool Generic_GCC::isPIEDefault() const { return false; }
-
-bool Generic_GCC::isPICDefaultForced() const {
-  return getArch() == llvm::Triple::x86_64 && getTriple().isOSWindows();
-}
-
-bool Generic_GCC::IsIntegratedAssemblerDefault() const {
-  switch (getTriple().getArch()) {
-  case llvm::Triple::x86:
-  case llvm::Triple::x86_64:
-  case llvm::Triple::aarch64:
-  case llvm::Triple::aarch64_be:
-  case llvm::Triple::arm:
-  case llvm::Triple::armeb:
-  case llvm::Triple::bpfel:
-  case llvm::Triple::bpfeb:
-  case llvm::Triple::thumb:
-  case llvm::Triple::thumbeb:
-  case llvm::Triple::ppc:
-  case llvm::Triple::ppc64:
-  case llvm::Triple::ppc64le:
-  case llvm::Triple::systemz:
-  case llvm::Triple::mips:
-  case llvm::Triple::mipsel:
-    return true;
-  case llvm::Triple::mips64:
-  case llvm::Triple::mips64el:
-    // Enabled for Debian mips64/mips64el only. Other targets are unable to
-    // distinguish N32 from N64.
-    if (getTriple().getEnvironment() == llvm::Triple::GNUABI64)
-      return true;
-    return false;
-  default:
-    return false;
-  }
-}
-
-void Generic_GCC::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
-                                               ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
-      DriverArgs.hasArg(options::OPT_nostdincxx))
-    return;
-
-  switch (GetCXXStdlibType(DriverArgs)) {
-  case ToolChain::CST_Libcxx: {
-    std::string Path = findLibCxxIncludePath();
-    if (!Path.empty())
-      addSystemInclude(DriverArgs, CC1Args, Path);
-    break;
-  }
-
-  case ToolChain::CST_Libstdcxx:
-    addLibStdCxxIncludePaths(DriverArgs, CC1Args);
-    break;
-  }
-}
-
-std::string Generic_GCC::findLibCxxIncludePath() const {
-  // FIXME: The Linux behavior would probaby be a better approach here.
-  return getDriver().SysRoot + "/usr/include/c++/v1";
-}
-
-void
-Generic_GCC::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
-                                      llvm::opt::ArgStringList &CC1Args) const {
-  // By default, we don't assume we know where libstdc++ might be installed.
-  // FIXME: If we have a valid GCCInstallation, use it.
-}
-
-/// \brief Helper to add the variant paths of a libstdc++ installation.
-bool Generic_GCC::addLibStdCXXIncludePaths(
-    Twine Base, Twine Suffix, StringRef GCCTriple, StringRef GCCMultiarchTriple,
-    StringRef TargetMultiarchTriple, Twine IncludeSuffix,
-    const ArgList &DriverArgs, ArgStringList &CC1Args) const {
-  if (!getVFS().exists(Base + Suffix))
-    return false;
-
-  addSystemInclude(DriverArgs, CC1Args, Base + Suffix);
-
-  // The vanilla GCC layout of libstdc++ headers uses a triple subdirectory. If
-  // that path exists or we have neither a GCC nor target multiarch triple, use
-  // this vanilla search path.
-  if ((GCCMultiarchTriple.empty() && TargetMultiarchTriple.empty()) ||
-      getVFS().exists(Base + Suffix + "/" + GCCTriple + IncludeSuffix)) {
-    addSystemInclude(DriverArgs, CC1Args,
-                     Base + Suffix + "/" + GCCTriple + IncludeSuffix);
-  } else {
-    // Otherwise try to use multiarch naming schemes which have normalized the
-    // triples and put the triple before the suffix.
-    //
-    // GCC surprisingly uses *both* the GCC triple with a multilib suffix and
-    // the target triple, so we support that here.
-    addSystemInclude(DriverArgs, CC1Args,
-                     Base + "/" + GCCMultiarchTriple + Suffix + IncludeSuffix);
-    addSystemInclude(DriverArgs, CC1Args,
-                     Base + "/" + TargetMultiarchTriple + Suffix);
-  }
-
-  addSystemInclude(DriverArgs, CC1Args, Base + Suffix + "/backward");
-  return true;
-}
-
-llvm::opt::DerivedArgList *
-Generic_GCC::TranslateArgs(const llvm::opt::DerivedArgList &Args, StringRef,
-                           Action::OffloadKind DeviceOffloadKind) const {
-
-  // If this tool chain is used for an OpenMP offloading device we have to make
-  // sure we always generate a shared library regardless of the commands the
-  // user passed to the host. This is required because the runtime library
-  // is required to load the device image dynamically at run time.
-  if (DeviceOffloadKind == Action::OFK_OpenMP) {
-    DerivedArgList *DAL = new DerivedArgList(Args.getBaseArgs());
-    const OptTable &Opts = getDriver().getOpts();
-
-    // Request the shared library. Given that these options are decided
-    // implicitly, they do not refer to any base argument.
-    DAL->AddFlagArg(/*BaseArg=*/nullptr, Opts.getOption(options::OPT_shared));
-    DAL->AddFlagArg(/*BaseArg=*/nullptr, Opts.getOption(options::OPT_fPIC));
-
-    // Filter all the arguments we don't care passing to the offloading
-    // toolchain as they can mess up with the creation of a shared library.
-    for (auto *A : Args) {
-      switch ((options::ID)A->getOption().getID()) {
-      default:
-        DAL->append(A);
-        break;
-      case options::OPT_shared:
-      case options::OPT_dynamic:
-      case options::OPT_static:
-      case options::OPT_fPIC:
-      case options::OPT_fno_PIC:
-      case options::OPT_fpic:
-      case options::OPT_fno_pic:
-      case options::OPT_fPIE:
-      case options::OPT_fno_PIE:
-      case options::OPT_fpie:
-      case options::OPT_fno_pie:
-        break;
-      }
-    }
-    return DAL;
-  }
-  return nullptr;
-}
-
-void Generic_ELF::addClangTargetOptions(const ArgList &DriverArgs,
-                                        ArgStringList &CC1Args) const {
-  const Generic_GCC::GCCVersion &V = GCCInstallation.getVersion();
-  bool UseInitArrayDefault =
-      getTriple().getArch() == llvm::Triple::aarch64 ||
-      getTriple().getArch() == llvm::Triple::aarch64_be ||
-      (getTriple().getOS() == llvm::Triple::Linux &&
-       (!V.isOlderThan(4, 7, 0) || getTriple().isAndroid())) ||
-      getTriple().getOS() == llvm::Triple::NaCl ||
-      (getTriple().getVendor() == llvm::Triple::MipsTechnologies &&
-       !getTriple().hasEnvironment());
-
-  if (DriverArgs.hasFlag(options::OPT_fuse_init_array,
-                         options::OPT_fno_use_init_array, UseInitArrayDefault))
-    CC1Args.push_back("-fuse-init-array");
-}
-
-/// Mips Toolchain
-MipsLLVMToolChain::MipsLLVMToolChain(const Driver &D,
-                                     const llvm::Triple &Triple,
-                                     const ArgList &Args)
-    : Linux(D, Triple, Args) {
-  // Select the correct multilib according to the given arguments.
-  DetectedMultilibs Result;
-  findMIPSMultilibs(D, Triple, "", Args, Result);
-  Multilibs = Result.Multilibs;
-  SelectedMultilib = Result.SelectedMultilib;
-
-  // Find out the library suffix based on the ABI.
-  LibSuffix = tools::mips::getMipsABILibSuffix(Args, Triple);
-  getFilePaths().clear();
-  getFilePaths().push_back(computeSysRoot() + "/usr/lib" + LibSuffix);
-}
-
-void MipsLLVMToolChain::AddClangSystemIncludeArgs(
-    const ArgList &DriverArgs, ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdinc))
-    return;
-
-  const Driver &D = getDriver();
-
-  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
-    SmallString<128> P(D.ResourceDir);
-    llvm::sys::path::append(P, "include");
-    addSystemInclude(DriverArgs, CC1Args, P);
-  }
-
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
-    return;
-
-  const auto &Callback = Multilibs.includeDirsCallback();
-  if (Callback) {
-    for (const auto &Path : Callback(SelectedMultilib))
-      addExternCSystemIncludeIfExists(DriverArgs, CC1Args,
-                                      D.getInstalledDir() + Path);
-  }
-}
-
-Tool *MipsLLVMToolChain::buildLinker() const {
-  return new tools::gnutools::Linker(*this);
-}
-
-std::string MipsLLVMToolChain::computeSysRoot() const {
-  if (!getDriver().SysRoot.empty())
-    return getDriver().SysRoot + SelectedMultilib.osSuffix();
-
-  const std::string InstalledDir(getDriver().getInstalledDir());
-  std::string SysRootPath =
-      InstalledDir + "/../sysroot" + SelectedMultilib.osSuffix();
-  if (llvm::sys::fs::exists(SysRootPath))
-    return SysRootPath;
-
-  return std::string();
-}
-
-ToolChain::CXXStdlibType
-MipsLLVMToolChain::GetCXXStdlibType(const ArgList &Args) const {
-  Arg *A = Args.getLastArg(options::OPT_stdlib_EQ);
-  if (A) {
-    StringRef Value = A->getValue();
-    if (Value != "libc++")
-      getDriver().Diag(diag::err_drv_invalid_stdlib_name)
-          << A->getAsString(Args);
-  }
-
-  return ToolChain::CST_Libcxx;
-}
-
-std::string MipsLLVMToolChain::findLibCxxIncludePath() const {
-  if (const auto &Callback = Multilibs.includeDirsCallback()) {
-    for (std::string Path : Callback(SelectedMultilib)) {
-      Path = getDriver().getInstalledDir() + Path + "/c++/v1";
-      if (llvm::sys::fs::exists(Path)) {
-        return Path;
-      }
-    }
-  }
-  return "";
-}
-
-void MipsLLVMToolChain::AddCXXStdlibLibArgs(const ArgList &Args,
-                                            ArgStringList &CmdArgs) const {
-  assert((GetCXXStdlibType(Args) == ToolChain::CST_Libcxx) &&
-         "Only -lc++ (aka libxx) is suported in this toolchain.");
-
-  CmdArgs.push_back("-lc++");
-  CmdArgs.push_back("-lc++abi");
-  CmdArgs.push_back("-lunwind");
-}
-
-std::string MipsLLVMToolChain::getCompilerRT(const ArgList &Args,
-                                             StringRef Component,
-                                             bool Shared) const {
-  SmallString<128> Path(getDriver().ResourceDir);
-  llvm::sys::path::append(Path, SelectedMultilib.osSuffix(), "lib" + LibSuffix,
-                          getOS());
-  llvm::sys::path::append(Path, Twine("libclang_rt." + Component + "-" +
-                                      "mips" + (Shared ? ".so" : ".a")));
-  return Path.str();
-}
-
-/// Hexagon Toolchain
-
-std::string HexagonToolChain::getHexagonTargetDir(
-      const std::string &InstalledDir,
-      const SmallVectorImpl<std::string> &PrefixDirs) const {
-  std::string InstallRelDir;
-  const Driver &D = getDriver();
-
-  // Locate the rest of the toolchain ...
-  for (auto &I : PrefixDirs)
-    if (D.getVFS().exists(I))
-      return I;
-
-  if (getVFS().exists(InstallRelDir = InstalledDir + "/../target"))
-    return InstallRelDir;
-
-  return InstalledDir;
-}
-
-Optional<unsigned> HexagonToolChain::getSmallDataThreshold(
-      const ArgList &Args) {
-  StringRef Gn = "";
-  if (Arg *A = Args.getLastArg(options::OPT_G, options::OPT_G_EQ,
-                               options::OPT_msmall_data_threshold_EQ)) {
-    Gn = A->getValue();
-  } else if (Args.getLastArg(options::OPT_shared, options::OPT_fpic,
-                             options::OPT_fPIC)) {
-    Gn = "0";
-  }
-
-  unsigned G;
-  if (!Gn.getAsInteger(10, G))
-    return G;
-
-  return None;
-}
-
-void HexagonToolChain::getHexagonLibraryPaths(const ArgList &Args,
-      ToolChain::path_list &LibPaths) const {
-  const Driver &D = getDriver();
-
-  //----------------------------------------------------------------------------
-  // -L Args
-  //----------------------------------------------------------------------------
-  for (Arg *A : Args.filtered(options::OPT_L))
-    for (const char *Value : A->getValues())
-      LibPaths.push_back(Value);
-
-  //----------------------------------------------------------------------------
-  // Other standard paths
-  //----------------------------------------------------------------------------
-  std::vector<std::string> RootDirs;
-  std::copy(D.PrefixDirs.begin(), D.PrefixDirs.end(),
-            std::back_inserter(RootDirs));
-
-  std::string TargetDir = getHexagonTargetDir(D.getInstalledDir(),
-                                              D.PrefixDirs);
-  if (std::find(RootDirs.begin(), RootDirs.end(), TargetDir) == RootDirs.end())
-    RootDirs.push_back(TargetDir);
-
-  bool HasPIC = Args.hasArg(options::OPT_fpic, options::OPT_fPIC);
-  // Assume G0 with -shared.
-  bool HasG0 = Args.hasArg(options::OPT_shared);
-  if (auto G = getSmallDataThreshold(Args))
-    HasG0 = G.getValue() == 0;
-
-  const std::string CpuVer = GetTargetCPUVersion(Args).str();
-  for (auto &Dir : RootDirs) {
-    std::string LibDir = Dir + "/hexagon/lib";
-    std::string LibDirCpu = LibDir + '/' + CpuVer;
-    if (HasG0) {
-      if (HasPIC)
-        LibPaths.push_back(LibDirCpu + "/G0/pic");
-      LibPaths.push_back(LibDirCpu + "/G0");
-    }
-    LibPaths.push_back(LibDirCpu);
-    LibPaths.push_back(LibDir);
-  }
-}
-
-HexagonToolChain::HexagonToolChain(const Driver &D, const llvm::Triple &Triple,
-                                   const llvm::opt::ArgList &Args)
-    : Linux(D, Triple, Args) {
-  const std::string TargetDir = getHexagonTargetDir(D.getInstalledDir(),
-                                                    D.PrefixDirs);
-
-  // Note: Generic_GCC::Generic_GCC adds InstalledDir and getDriver().Dir to
-  // program paths
-  const std::string BinDir(TargetDir + "/bin");
-  if (D.getVFS().exists(BinDir))
-    getProgramPaths().push_back(BinDir);
-
-  ToolChain::path_list &LibPaths = getFilePaths();
-
-  // Remove paths added by Linux toolchain. Currently Hexagon_TC really targets
-  // 'elf' OS type, so the Linux paths are not appropriate. When we actually
-  // support 'linux' we'll need to fix this up
-  LibPaths.clear();
-  getHexagonLibraryPaths(Args, LibPaths);
-}
-
-HexagonToolChain::~HexagonToolChain() {}
-
-Tool *HexagonToolChain::buildAssembler() const {
-  return new tools::hexagon::Assembler(*this);
-}
-
-Tool *HexagonToolChain::buildLinker() const {
-  return new tools::hexagon::Linker(*this);
-}
-
-void HexagonToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
-                                                 ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdinc) ||
-      DriverArgs.hasArg(options::OPT_nostdlibinc))
-    return;
-
-  const Driver &D = getDriver();
-  std::string TargetDir = getHexagonTargetDir(D.getInstalledDir(),
-                                              D.PrefixDirs);
-  addExternCSystemInclude(DriverArgs, CC1Args, TargetDir + "/hexagon/include");
-}
-
-
-void HexagonToolChain::addLibStdCxxIncludePaths(
-    const llvm::opt::ArgList &DriverArgs,
-    llvm::opt::ArgStringList &CC1Args) const {
-  const Driver &D = getDriver();
-  std::string TargetDir = getHexagonTargetDir(D.InstalledDir, D.PrefixDirs);
-  addLibStdCXXIncludePaths(TargetDir, "/hexagon/include/c++", "", "", "", "",
-                           DriverArgs, CC1Args);
-}
-
-ToolChain::CXXStdlibType
-HexagonToolChain::GetCXXStdlibType(const ArgList &Args) const {
-  Arg *A = Args.getLastArg(options::OPT_stdlib_EQ);
-  if (!A)
-    return ToolChain::CST_Libstdcxx;
-
-  StringRef Value = A->getValue();
-  if (Value != "libstdc++")
-    getDriver().Diag(diag::err_drv_invalid_stdlib_name) << A->getAsString(Args);
-
-  return ToolChain::CST_Libstdcxx;
-}
-
-//
-// Returns the default CPU for Hexagon. This is the default compilation target
-// if no Hexagon processor is selected at the command-line.
-//
-const StringRef HexagonToolChain::GetDefaultCPU() {
-  return "hexagonv60";
-}
-
-const StringRef HexagonToolChain::GetTargetCPUVersion(const ArgList &Args) {
-  Arg *CpuArg = nullptr;
-  if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ, options::OPT_march_EQ))
-    CpuArg = A;
-
-  StringRef CPU = CpuArg ? CpuArg->getValue() : GetDefaultCPU();
-  if (CPU.startswith("hexagon"))
-    return CPU.substr(sizeof("hexagon") - 1);
-  return CPU;
-}
-// End Hexagon
-
-/// AMDGPU Toolchain
-AMDGPUToolChain::AMDGPUToolChain(const Driver &D, const llvm::Triple &Triple,
-                                 const ArgList &Args)
-  : Generic_ELF(D, Triple, Args) { }
-
-Tool *AMDGPUToolChain::buildLinker() const {
-  return new tools::amdgpu::Linker(*this);
-}
-// End AMDGPU
-
-/// NaCl Toolchain
-NaClToolChain::NaClToolChain(const Driver &D, const llvm::Triple &Triple,
-                             const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {
-
-  // Remove paths added by Generic_GCC. NaCl Toolchain cannot use the
-  // default paths, and must instead only use the paths provided
-  // with this toolchain based on architecture.
-  path_list &file_paths = getFilePaths();
-  path_list &prog_paths = getProgramPaths();
-
-  file_paths.clear();
-  prog_paths.clear();
-
-  // Path for library files (libc.a, ...)
-  std::string FilePath(getDriver().Dir + "/../");
-
-  // Path for tools (clang, ld, etc..)
-  std::string ProgPath(getDriver().Dir + "/../");
-
-  // Path for toolchain libraries (libgcc.a, ...)
-  std::string ToolPath(getDriver().ResourceDir + "/lib/");
-
-  switch (Triple.getArch()) {
-  case llvm::Triple::x86:
-    file_paths.push_back(FilePath + "x86_64-nacl/lib32");
-    file_paths.push_back(FilePath + "i686-nacl/usr/lib");
-    prog_paths.push_back(ProgPath + "x86_64-nacl/bin");
-    file_paths.push_back(ToolPath + "i686-nacl");
-    break;
-  case llvm::Triple::x86_64:
-    file_paths.push_back(FilePath + "x86_64-nacl/lib");
-    file_paths.push_back(FilePath + "x86_64-nacl/usr/lib");
-    prog_paths.push_back(ProgPath + "x86_64-nacl/bin");
-    file_paths.push_back(ToolPath + "x86_64-nacl");
-    break;
-  case llvm::Triple::arm:
-    file_paths.push_back(FilePath + "arm-nacl/lib");
-    file_paths.push_back(FilePath + "arm-nacl/usr/lib");
-    prog_paths.push_back(ProgPath + "arm-nacl/bin");
-    file_paths.push_back(ToolPath + "arm-nacl");
-    break;
-  case llvm::Triple::mipsel:
-    file_paths.push_back(FilePath + "mipsel-nacl/lib");
-    file_paths.push_back(FilePath + "mipsel-nacl/usr/lib");
-    prog_paths.push_back(ProgPath + "bin");
-    file_paths.push_back(ToolPath + "mipsel-nacl");
-    break;
-  default:
-    break;
-  }
-
-  NaClArmMacrosPath = GetFilePath("nacl-arm-macros.s");
-}
-
-void NaClToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
-                                              ArgStringList &CC1Args) const {
-  const Driver &D = getDriver();
-  if (DriverArgs.hasArg(options::OPT_nostdinc))
-    return;
-
-  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
-    SmallString<128> P(D.ResourceDir);
-    llvm::sys::path::append(P, "include");
-    addSystemInclude(DriverArgs, CC1Args, P.str());
-  }
-
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
-    return;
-
-  SmallString<128> P(D.Dir + "/../");
-  switch (getTriple().getArch()) {
-  case llvm::Triple::x86:
-    // x86 is special because multilib style uses x86_64-nacl/include for libc
-    // headers but the SDK wants i686-nacl/usr/include. The other architectures
-    // have the same substring.
-    llvm::sys::path::append(P, "i686-nacl/usr/include");
-    addSystemInclude(DriverArgs, CC1Args, P.str());
-    llvm::sys::path::remove_filename(P);
-    llvm::sys::path::remove_filename(P);
-    llvm::sys::path::remove_filename(P);
-    llvm::sys::path::append(P, "x86_64-nacl/include");
-    addSystemInclude(DriverArgs, CC1Args, P.str());
-    return;
-  case llvm::Triple::arm:
-    llvm::sys::path::append(P, "arm-nacl/usr/include");
-    break;
-  case llvm::Triple::x86_64:
-    llvm::sys::path::append(P, "x86_64-nacl/usr/include");
-    break;
-  case llvm::Triple::mipsel:
-    llvm::sys::path::append(P, "mipsel-nacl/usr/include");
-    break;
-  default:
-    return;
-  }
-
-  addSystemInclude(DriverArgs, CC1Args, P.str());
-  llvm::sys::path::remove_filename(P);
-  llvm::sys::path::remove_filename(P);
-  llvm::sys::path::append(P, "include");
-  addSystemInclude(DriverArgs, CC1Args, P.str());
-}
-
-void NaClToolChain::AddCXXStdlibLibArgs(const ArgList &Args,
-                                        ArgStringList &CmdArgs) const {
-  // Check for -stdlib= flags. We only support libc++ but this consumes the arg
-  // if the value is libc++, and emits an error for other values.
-  GetCXXStdlibType(Args);
-  CmdArgs.push_back("-lc++");
-}
-
-std::string NaClToolChain::findLibCxxIncludePath() const {
-  const Driver &D = getDriver();
-
-  SmallString<128> P(D.Dir + "/../");
-  switch (getTriple().getArch()) {
-  case llvm::Triple::arm:
-    llvm::sys::path::append(P, "arm-nacl/include/c++/v1");
-    return P.str();
-  case llvm::Triple::x86:
-    llvm::sys::path::append(P, "x86_64-nacl/include/c++/v1");
-    return P.str();
-  case llvm::Triple::x86_64:
-    llvm::sys::path::append(P, "x86_64-nacl/include/c++/v1");
-    return P.str();
-  case llvm::Triple::mipsel:
-    llvm::sys::path::append(P, "mipsel-nacl/include/c++/v1");
-    return P.str();
-  default:
-    return "";
-  }
-}
-
-ToolChain::CXXStdlibType
-NaClToolChain::GetCXXStdlibType(const ArgList &Args) const {
-  if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
-    StringRef Value = A->getValue();
-    if (Value == "libc++")
-      return ToolChain::CST_Libcxx;
-    getDriver().Diag(diag::err_drv_invalid_stdlib_name) << A->getAsString(Args);
-  }
-
-  return ToolChain::CST_Libcxx;
-}
-
-std::string
-NaClToolChain::ComputeEffectiveClangTriple(const ArgList &Args,
-                                           types::ID InputType) const {
-  llvm::Triple TheTriple(ComputeLLVMTriple(Args, InputType));
-  if (TheTriple.getArch() == llvm::Triple::arm &&
-      TheTriple.getEnvironment() == llvm::Triple::UnknownEnvironment)
-    TheTriple.setEnvironment(llvm::Triple::GNUEABIHF);
-  return TheTriple.getTriple();
-}
-
-Tool *NaClToolChain::buildLinker() const {
-  return new tools::nacltools::Linker(*this);
-}
-
-Tool *NaClToolChain::buildAssembler() const {
-  if (getTriple().getArch() == llvm::Triple::arm)
-    return new tools::nacltools::AssemblerARM(*this);
-  return new tools::gnutools::Assembler(*this);
-}
-// End NaCl
-
-/// TCEToolChain - A tool chain using the llvm bitcode tools to perform
-/// all subcommands. See http://tce.cs.tut.fi for our peculiar target.
-/// Currently does not support anything else but compilation.
-
-TCEToolChain::TCEToolChain(const Driver &D, const llvm::Triple &Triple,
-                           const ArgList &Args)
-    : ToolChain(D, Triple, Args) {
-  // Path mangling to find libexec
-  std::string Path(getDriver().Dir);
-
-  Path += "/../libexec";
-  getProgramPaths().push_back(Path);
-}
-
-TCEToolChain::~TCEToolChain() {}
-
-bool TCEToolChain::IsMathErrnoDefault() const { return true; }
-
-bool TCEToolChain::isPICDefault() const { return false; }
-
-bool TCEToolChain::isPIEDefault() const { return false; }
-
-bool TCEToolChain::isPICDefaultForced() const { return false; }
-
-TCELEToolChain::TCELEToolChain(const Driver &D, const llvm::Triple& Triple,
-                               const ArgList &Args)
-  : TCEToolChain(D, Triple, Args) {
-}
-
-TCELEToolChain::~TCELEToolChain() {}
-
-// CloudABI - CloudABI tool chain which can call ld(1) directly.
-
-CloudABI::CloudABI(const Driver &D, const llvm::Triple &Triple,
-                   const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {
-  SmallString<128> P(getDriver().Dir);
-  llvm::sys::path::append(P, "..", getTriple().str(), "lib");
-  getFilePaths().push_back(P.str());
-}
-
-std::string CloudABI::findLibCxxIncludePath() const {
-  SmallString<128> P(getDriver().Dir);
-  llvm::sys::path::append(P, "..", getTriple().str(), "include/c++/v1");
-  return P.str();
-}
-
-void CloudABI::AddCXXStdlibLibArgs(const ArgList &Args,
-                                   ArgStringList &CmdArgs) const {
-  CmdArgs.push_back("-lc++");
-  CmdArgs.push_back("-lc++abi");
-  CmdArgs.push_back("-lunwind");
-}
-
-Tool *CloudABI::buildLinker() const {
-  return new tools::cloudabi::Linker(*this);
-}
-
-bool CloudABI::isPIEDefault() const {
-  // Only enable PIE on architectures that support PC-relative
-  // addressing. PC-relative addressing is required, as the process
-  // startup code must be able to relocate itself.
-  switch (getTriple().getArch()) {
-  case llvm::Triple::aarch64:
-  case llvm::Triple::x86_64:
-    return true;
-  default:
-    return false;
-  }
-}
-
-SanitizerMask CloudABI::getSupportedSanitizers() const {
-  SanitizerMask Res = ToolChain::getSupportedSanitizers();
-  Res |= SanitizerKind::SafeStack;
-  return Res;
-}
-
-SanitizerMask CloudABI::getDefaultSanitizers() const {
-  return SanitizerKind::SafeStack;
-}
-
-/// Haiku - Haiku tool chain which can call as(1) and ld(1) directly.
-
-Haiku::Haiku(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
-  : Generic_ELF(D, Triple, Args) {
-
-}
-
-std::string Haiku::findLibCxxIncludePath() const {
-  return getDriver().SysRoot + "/system/develop/headers/c++/v1";
-}
-
-void Haiku::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
-                                     llvm::opt::ArgStringList &CC1Args) const {
-  addLibStdCXXIncludePaths(getDriver().SysRoot, "/system/develop/headers/c++",
-                           getTriple().str(), "", "", "", DriverArgs, CC1Args);
-}
-
-/// OpenBSD - OpenBSD tool chain which can call as(1) and ld(1) directly.
-
-OpenBSD::OpenBSD(const Driver &D, const llvm::Triple &Triple,
-                 const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {
-  getFilePaths().push_back(getDriver().Dir + "/../lib");
-  getFilePaths().push_back("/usr/lib");
-}
-
-Tool *OpenBSD::buildAssembler() const {
-  return new tools::openbsd::Assembler(*this);
-}
-
-Tool *OpenBSD::buildLinker() const { return new tools::openbsd::Linker(*this); }
-
-/// Bitrig - Bitrig tool chain which can call as(1) and ld(1) directly.
-
-Bitrig::Bitrig(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {
-  getFilePaths().push_back(getDriver().Dir + "/../lib");
-  getFilePaths().push_back("/usr/lib");
-}
-
-Tool *Bitrig::buildAssembler() const {
-  return new tools::bitrig::Assembler(*this);
-}
-
-Tool *Bitrig::buildLinker() const { return new tools::bitrig::Linker(*this); }
-
-ToolChain::CXXStdlibType Bitrig::GetDefaultCXXStdlibType() const {
-  return ToolChain::CST_Libcxx;
-}
-
-void Bitrig::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
-                                      llvm::opt::ArgStringList &CC1Args) const {
-  std::string Triple = getTriple().str();
-  if (StringRef(Triple).startswith("amd64"))
-    Triple = "x86_64" + Triple.substr(5);
-  addLibStdCXXIncludePaths(getDriver().SysRoot, "/usr/include/c++/stdc++",
-                           Triple, "", "", "", DriverArgs, CC1Args);
-}
-
-void Bitrig::AddCXXStdlibLibArgs(const ArgList &Args,
-                                 ArgStringList &CmdArgs) const {
-  switch (GetCXXStdlibType(Args)) {
-  case ToolChain::CST_Libcxx:
-    CmdArgs.push_back("-lc++");
-    CmdArgs.push_back("-lc++abi");
-    CmdArgs.push_back("-lpthread");
-    break;
-  case ToolChain::CST_Libstdcxx:
-    CmdArgs.push_back("-lstdc++");
-    break;
-  }
-}
-
-/// FreeBSD - FreeBSD tool chain which can call as(1) and ld(1) directly.
-
-FreeBSD::FreeBSD(const Driver &D, const llvm::Triple &Triple,
-                 const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {
-
-  // When targeting 32-bit platforms, look for '/usr/lib32/crt1.o' and fall
-  // back to '/usr/lib' if it doesn't exist.
-  if ((Triple.getArch() == llvm::Triple::x86 ||
-       Triple.getArch() == llvm::Triple::ppc) &&
-      D.getVFS().exists(getDriver().SysRoot + "/usr/lib32/crt1.o"))
-    getFilePaths().push_back(getDriver().SysRoot + "/usr/lib32");
-  else
-    getFilePaths().push_back(getDriver().SysRoot + "/usr/lib");
-}
-
-ToolChain::CXXStdlibType FreeBSD::GetDefaultCXXStdlibType() const {
-  if (getTriple().getOSMajorVersion() >= 10)
-    return ToolChain::CST_Libcxx;
-  return ToolChain::CST_Libstdcxx;
-}
-
-void FreeBSD::addLibStdCxxIncludePaths(
-    const llvm::opt::ArgList &DriverArgs,
-    llvm::opt::ArgStringList &CC1Args) const {
-  addLibStdCXXIncludePaths(getDriver().SysRoot, "/usr/include/c++/4.2", "", "",
-                           "", "", DriverArgs, CC1Args);
-}
-
-void FreeBSD::AddCXXStdlibLibArgs(const ArgList &Args,
-                                  ArgStringList &CmdArgs) const {
-  CXXStdlibType Type = GetCXXStdlibType(Args);
-  bool Profiling = Args.hasArg(options::OPT_pg);
-
-  switch (Type) {
-  case ToolChain::CST_Libcxx:
-    CmdArgs.push_back(Profiling ? "-lc++_p" : "-lc++");
-    break;
-
-  case ToolChain::CST_Libstdcxx:
-    CmdArgs.push_back(Profiling ? "-lstdc++_p" : "-lstdc++");
-    break;
-  }
-}
-
-Tool *FreeBSD::buildAssembler() const {
-  return new tools::freebsd::Assembler(*this);
-}
-
-Tool *FreeBSD::buildLinker() const { return new tools::freebsd::Linker(*this); }
-
-bool FreeBSD::UseSjLjExceptions(const ArgList &Args) const {
-  // FreeBSD uses SjLj exceptions on ARM oabi.
-  switch (getTriple().getEnvironment()) {
-  case llvm::Triple::GNUEABIHF:
-  case llvm::Triple::GNUEABI:
-  case llvm::Triple::EABI:
-    return false;
-
-  default:
-    return (getTriple().getArch() == llvm::Triple::arm ||
-            getTriple().getArch() == llvm::Triple::thumb);
-  }
-}
-
-bool FreeBSD::HasNativeLLVMSupport() const { return true; }
-
-bool FreeBSD::isPIEDefault() const { return getSanitizerArgs().requiresPIE(); }
-
-SanitizerMask FreeBSD::getSupportedSanitizers() const {
-  const bool IsX86 = getTriple().getArch() == llvm::Triple::x86;
-  const bool IsX86_64 = getTriple().getArch() == llvm::Triple::x86_64;
-  const bool IsMIPS64 = getTriple().getArch() == llvm::Triple::mips64 ||
-                        getTriple().getArch() == llvm::Triple::mips64el;
-  SanitizerMask Res = ToolChain::getSupportedSanitizers();
-  Res |= SanitizerKind::Address;
-  Res |= SanitizerKind::Vptr;
-  if (IsX86_64 || IsMIPS64) {
-    Res |= SanitizerKind::Leak;
-    Res |= SanitizerKind::Thread;
-  }
-  if (IsX86 || IsX86_64) {
-    Res |= SanitizerKind::SafeStack;
-  }
-  return Res;
-}
-
-/// NetBSD - NetBSD tool chain which can call as(1) and ld(1) directly.
-
-NetBSD::NetBSD(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {
-  if (getDriver().UseStdLib) {
-    // When targeting a 32-bit platform, try the special directory used on
-    // 64-bit hosts, and only fall back to the main library directory if that
-    // doesn't work.
-    // FIXME: It'd be nicer to test if this directory exists, but I'm not sure
-    // what all logic is needed to emulate the '=' prefix here.
-    switch (Triple.getArch()) {
-    case llvm::Triple::x86:
-      getFilePaths().push_back("=/usr/lib/i386");
-      break;
-    case llvm::Triple::arm:
-    case llvm::Triple::armeb:
-    case llvm::Triple::thumb:
-    case llvm::Triple::thumbeb:
-      switch (Triple.getEnvironment()) {
-      case llvm::Triple::EABI:
-      case llvm::Triple::GNUEABI:
-        getFilePaths().push_back("=/usr/lib/eabi");
-        break;
-      case llvm::Triple::EABIHF:
-      case llvm::Triple::GNUEABIHF:
-        getFilePaths().push_back("=/usr/lib/eabihf");
-        break;
-      default:
-        getFilePaths().push_back("=/usr/lib/oabi");
-        break;
-      }
-      break;
-    case llvm::Triple::mips64:
-    case llvm::Triple::mips64el:
-      if (tools::mips::hasMipsAbiArg(Args, "o32"))
-        getFilePaths().push_back("=/usr/lib/o32");
-      else if (tools::mips::hasMipsAbiArg(Args, "64"))
-        getFilePaths().push_back("=/usr/lib/64");
-      break;
-    case llvm::Triple::ppc:
-      getFilePaths().push_back("=/usr/lib/powerpc");
-      break;
-    case llvm::Triple::sparc:
-      getFilePaths().push_back("=/usr/lib/sparc");
-      break;
-    default:
-      break;
-    }
-
-    getFilePaths().push_back("=/usr/lib");
-  }
-}
-
-Tool *NetBSD::buildAssembler() const {
-  return new tools::netbsd::Assembler(*this);
-}
-
-Tool *NetBSD::buildLinker() const { return new tools::netbsd::Linker(*this); }
-
-ToolChain::CXXStdlibType NetBSD::GetDefaultCXXStdlibType() const {
-  unsigned Major, Minor, Micro;
-  getTriple().getOSVersion(Major, Minor, Micro);
-  if (Major >= 7 || Major == 0) {
-    switch (getArch()) {
-    case llvm::Triple::aarch64:
-    case llvm::Triple::aarch64_be:
-    case llvm::Triple::arm:
-    case llvm::Triple::armeb:
-    case llvm::Triple::thumb:
-    case llvm::Triple::thumbeb:
-    case llvm::Triple::ppc:
-    case llvm::Triple::ppc64:
-    case llvm::Triple::ppc64le:
-    case llvm::Triple::sparc:
-    case llvm::Triple::sparcv9:
-    case llvm::Triple::x86:
-    case llvm::Triple::x86_64:
-      return ToolChain::CST_Libcxx;
-    default:
-      break;
-    }
-  }
-  return ToolChain::CST_Libstdcxx;
-}
-
-std::string NetBSD::findLibCxxIncludePath() const {
-  return getDriver().SysRoot + "/usr/include/c++/";
-}
-
-void NetBSD::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
-                                      llvm::opt::ArgStringList &CC1Args) const {
-  addLibStdCXXIncludePaths(getDriver().SysRoot, "/usr/include/g++", "", "", "",
-                           "", DriverArgs, CC1Args);
-}
-
-/// Minix - Minix tool chain which can call as(1) and ld(1) directly.
-
-Minix::Minix(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {
-  getFilePaths().push_back(getDriver().Dir + "/../lib");
-  getFilePaths().push_back("/usr/lib");
-}
-
-Tool *Minix::buildAssembler() const {
-  return new tools::minix::Assembler(*this);
-}
-
-Tool *Minix::buildLinker() const { return new tools::minix::Linker(*this); }
-
-static void addPathIfExists(const Driver &D, const Twine &Path,
-                            ToolChain::path_list &Paths) {
-  if (D.getVFS().exists(Path))
-    Paths.push_back(Path.str());
-}
-
-/// Solaris - Solaris tool chain which can call as(1) and ld(1) directly.
-
-Solaris::Solaris(const Driver &D, const llvm::Triple &Triple,
-                 const ArgList &Args)
-    : Generic_GCC(D, Triple, Args) {
-
-  GCCInstallation.init(Triple, Args);
-
-  path_list &Paths = getFilePaths();
-  if (GCCInstallation.isValid())
-    addPathIfExists(D, GCCInstallation.getInstallPath(), Paths);
-
-  addPathIfExists(D, getDriver().getInstalledDir(), Paths);
-  if (getDriver().getInstalledDir() != getDriver().Dir)
-    addPathIfExists(D, getDriver().Dir, Paths);
-
-  addPathIfExists(D, getDriver().SysRoot + getDriver().Dir + "/../lib", Paths);
-
-  std::string LibPath = "/usr/lib/";
-  switch (Triple.getArch()) {
-  case llvm::Triple::x86:
-  case llvm::Triple::sparc:
-    break;
-  case llvm::Triple::x86_64:
-    LibPath += "amd64/";
-    break;
-  case llvm::Triple::sparcv9:
-    LibPath += "sparcv9/";
-    break;
-  default:
-    llvm_unreachable("Unsupported architecture");
-  }
-
-  addPathIfExists(D, getDriver().SysRoot + LibPath, Paths);
-}
-
-Tool *Solaris::buildAssembler() const {
-  return new tools::solaris::Assembler(*this);
-}
-
-Tool *Solaris::buildLinker() const { return new tools::solaris::Linker(*this); }
-
-void Solaris::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
-                                           ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
-      DriverArgs.hasArg(options::OPT_nostdincxx))
-    return;
-
-  // Include the support directory for things like xlocale and fudged system
-  // headers.
-  // FIXME: This is a weird mix of libc++ and libstdc++. We should also be
-  // checking the value of -stdlib= here and adding the includes for libc++
-  // rather than libstdc++ if it's requested.
-  addSystemInclude(DriverArgs, CC1Args, "/usr/include/c++/v1/support/solaris");
-
-  if (GCCInstallation.isValid()) {
-    GCCVersion Version = GCCInstallation.getVersion();
-    addSystemInclude(DriverArgs, CC1Args,
-                     getDriver().SysRoot + "/usr/gcc/" +
-                     Version.MajorStr + "." +
-                     Version.MinorStr +
-                     "/include/c++/" + Version.Text);
-    addSystemInclude(DriverArgs, CC1Args,
-                     getDriver().SysRoot + "/usr/gcc/" + Version.MajorStr +
-                     "." + Version.MinorStr + "/include/c++/" +
-                     Version.Text + "/" +
-                     GCCInstallation.getTriple().str());
-  }
-}
-
-/// \brief Get our best guess at the multiarch triple for a target.
-///
-/// Debian-based systems are starting to use a multiarch setup where they use
-/// a target-triple directory in the library and header search paths.
-/// Unfortunately, this triple does not align with the vanilla target triple,
-/// so we provide a rough mapping here.
-static std::string getMultiarchTriple(const Driver &D,
-                                      const llvm::Triple &TargetTriple,
-                                      StringRef SysRoot) {
-  llvm::Triple::EnvironmentType TargetEnvironment =
-      TargetTriple.getEnvironment();
-
-  // For most architectures, just use whatever we have rather than trying to be
-  // clever.
-  switch (TargetTriple.getArch()) {
-  default:
-    break;
-
-  // We use the existence of '/lib/<triple>' as a directory to detect some
-  // common linux triples that don't quite match the Clang triple for both
-  // 32-bit and 64-bit targets. Multiarch fixes its install triples to these
-  // regardless of what the actual target triple is.
-  case llvm::Triple::arm:
-  case llvm::Triple::thumb:
-    if (TargetEnvironment == llvm::Triple::GNUEABIHF) {
-      if (D.getVFS().exists(SysRoot + "/lib/arm-linux-gnueabihf"))
-        return "arm-linux-gnueabihf";
-    } else {
-      if (D.getVFS().exists(SysRoot + "/lib/arm-linux-gnueabi"))
-        return "arm-linux-gnueabi";
-    }
-    break;
-  case llvm::Triple::armeb:
-  case llvm::Triple::thumbeb:
-    if (TargetEnvironment == llvm::Triple::GNUEABIHF) {
-      if (D.getVFS().exists(SysRoot + "/lib/armeb-linux-gnueabihf"))
-        return "armeb-linux-gnueabihf";
-    } else {
-      if (D.getVFS().exists(SysRoot + "/lib/armeb-linux-gnueabi"))
-        return "armeb-linux-gnueabi";
-    }
-    break;
-  case llvm::Triple::x86:
-    if (D.getVFS().exists(SysRoot + "/lib/i386-linux-gnu"))
-      return "i386-linux-gnu";
-    break;
-  case llvm::Triple::x86_64:
-    // We don't want this for x32, otherwise it will match x86_64 libs
-    if (TargetEnvironment != llvm::Triple::GNUX32 &&
-        D.getVFS().exists(SysRoot + "/lib/x86_64-linux-gnu"))
-      return "x86_64-linux-gnu";
-    break;
-  case llvm::Triple::aarch64:
-    if (D.getVFS().exists(SysRoot + "/lib/aarch64-linux-gnu"))
-      return "aarch64-linux-gnu";
-    break;
-  case llvm::Triple::aarch64_be:
-    if (D.getVFS().exists(SysRoot + "/lib/aarch64_be-linux-gnu"))
-      return "aarch64_be-linux-gnu";
-    break;
-  case llvm::Triple::mips:
-    if (D.getVFS().exists(SysRoot + "/lib/mips-linux-gnu"))
-      return "mips-linux-gnu";
-    break;
-  case llvm::Triple::mipsel:
-    if (D.getVFS().exists(SysRoot + "/lib/mipsel-linux-gnu"))
-      return "mipsel-linux-gnu";
-    break;
-  case llvm::Triple::mips64:
-    if (D.getVFS().exists(SysRoot + "/lib/mips64-linux-gnu"))
-      return "mips64-linux-gnu";
-    if (D.getVFS().exists(SysRoot + "/lib/mips64-linux-gnuabi64"))
-      return "mips64-linux-gnuabi64";
-    break;
-  case llvm::Triple::mips64el:
-    if (D.getVFS().exists(SysRoot + "/lib/mips64el-linux-gnu"))
-      return "mips64el-linux-gnu";
-    if (D.getVFS().exists(SysRoot + "/lib/mips64el-linux-gnuabi64"))
-      return "mips64el-linux-gnuabi64";
-    break;
-  case llvm::Triple::ppc:
-    if (D.getVFS().exists(SysRoot + "/lib/powerpc-linux-gnuspe"))
-      return "powerpc-linux-gnuspe";
-    if (D.getVFS().exists(SysRoot + "/lib/powerpc-linux-gnu"))
-      return "powerpc-linux-gnu";
-    break;
-  case llvm::Triple::ppc64:
-    if (D.getVFS().exists(SysRoot + "/lib/powerpc64-linux-gnu"))
-      return "powerpc64-linux-gnu";
-    break;
-  case llvm::Triple::ppc64le:
-    if (D.getVFS().exists(SysRoot + "/lib/powerpc64le-linux-gnu"))
-      return "powerpc64le-linux-gnu";
-    break;
-  case llvm::Triple::sparc:
-    if (D.getVFS().exists(SysRoot + "/lib/sparc-linux-gnu"))
-      return "sparc-linux-gnu";
-    break;
-  case llvm::Triple::sparcv9:
-    if (D.getVFS().exists(SysRoot + "/lib/sparc64-linux-gnu"))
-      return "sparc64-linux-gnu";
-    break;
-  case llvm::Triple::systemz:
-    if (D.getVFS().exists(SysRoot + "/lib/s390x-linux-gnu"))
-      return "s390x-linux-gnu";
-    break;
-  }
-  return TargetTriple.str();
-}
-
-static StringRef getOSLibDir(const llvm::Triple &Triple, const ArgList &Args) {
-  if (isMipsArch(Triple.getArch())) {
-    if (Triple.isAndroid()) {
-      StringRef CPUName;
-      StringRef ABIName;
-      tools::mips::getMipsCPUAndABI(Args, Triple, CPUName, ABIName);
-      if (CPUName == "mips32r6")
-        return "libr6";
-      if (CPUName == "mips32r2")
-        return "libr2";
-    }
-    // lib32 directory has a special meaning on MIPS targets.
-    // It contains N32 ABI binaries. Use this folder if produce
-    // code for N32 ABI only.
-    if (tools::mips::hasMipsAbiArg(Args, "n32"))
-      return "lib32";
-    return Triple.isArch32Bit() ? "lib" : "lib64";
-  }
-
-  // It happens that only x86 and PPC use the 'lib32' variant of oslibdir, and
-  // using that variant while targeting other architectures causes problems
-  // because the libraries are laid out in shared system roots that can't cope
-  // with a 'lib32' library search path being considered. So we only enable
-  // them when we know we may need it.
-  //
-  // FIXME: This is a bit of a hack. We should really unify this code for
-  // reasoning about oslibdir spellings with the lib dir spellings in the
-  // GCCInstallationDetector, but that is a more significant refactoring.
-  if (Triple.getArch() == llvm::Triple::x86 ||
-      Triple.getArch() == llvm::Triple::ppc)
-    return "lib32";
-
-  if (Triple.getArch() == llvm::Triple::x86_64 &&
-      Triple.getEnvironment() == llvm::Triple::GNUX32)
-    return "libx32";
-
-  return Triple.isArch32Bit() ? "lib" : "lib64";
-}
-
-static void addMultilibsFilePaths(const Driver &D, const MultilibSet &Multilibs,
-                                  const Multilib &Multilib,
-                                  StringRef InstallPath,
-                                  ToolChain::path_list &Paths) {
-  if (const auto &PathsCallback = Multilibs.filePathsCallback())
-    for (const auto &Path : PathsCallback(Multilib))
-      addPathIfExists(D, InstallPath + Path, Paths);
-}
-
-Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {
-  GCCInstallation.init(Triple, Args);
-  Multilibs = GCCInstallation.getMultilibs();
-  llvm::Triple::ArchType Arch = Triple.getArch();
-  std::string SysRoot = computeSysRoot();
-
-  // Cross-compiling binutils and GCC installations (vanilla and openSUSE at
-  // least) put various tools in a triple-prefixed directory off of the parent
-  // of the GCC installation. We use the GCC triple here to ensure that we end
-  // up with tools that support the same amount of cross compiling as the
-  // detected GCC installation. For example, if we find a GCC installation
-  // targeting x86_64, but it is a bi-arch GCC installation, it can also be
-  // used to target i386.
-  // FIXME: This seems unlikely to be Linux-specific.
-  ToolChain::path_list &PPaths = getProgramPaths();
-  PPaths.push_back(Twine(GCCInstallation.getParentLibPath() + "/../" +
-                         GCCInstallation.getTriple().str() + "/bin")
-                       .str());
-
-  Distro Distro(D.getVFS());
-
-  if (Distro.IsOpenSUSE() || Distro.IsUbuntu()) {
-    ExtraOpts.push_back("-z");
-    ExtraOpts.push_back("relro");
-  }
-
-  if (Arch == llvm::Triple::arm || Arch == llvm::Triple::thumb)
-    ExtraOpts.push_back("-X");
-
-  const bool IsAndroid = Triple.isAndroid();
-  const bool IsMips = isMipsArch(Arch);
-
-  if (IsMips && !SysRoot.empty())
-    ExtraOpts.push_back("--sysroot=" + SysRoot);
-
-  // Do not use 'gnu' hash style for Mips targets because .gnu.hash
-  // and the MIPS ABI require .dynsym to be sorted in different ways.
-  // .gnu.hash needs symbols to be grouped by hash code whereas the MIPS
-  // ABI requires a mapping between the GOT and the symbol table.
-  // Android loader does not support .gnu.hash.
-  if (!IsMips && !IsAndroid) {
-    if (Distro.IsRedhat() || Distro.IsOpenSUSE() ||
-        (Distro.IsUbuntu() && Distro >= Distro::UbuntuMaverick))
-      ExtraOpts.push_back("--hash-style=gnu");
-
-    if (Distro.IsDebian() || Distro.IsOpenSUSE() || Distro == Distro::UbuntuLucid ||
-        Distro == Distro::UbuntuJaunty || Distro == Distro::UbuntuKarmic)
-      ExtraOpts.push_back("--hash-style=both");
-  }
-
-  if (Distro.IsRedhat() && Distro != Distro::RHEL5 && Distro != Distro::RHEL6)
-    ExtraOpts.push_back("--no-add-needed");
-
-#ifdef ENABLE_LINKER_BUILD_ID
-  ExtraOpts.push_back("--build-id");
-#endif
-
-  if (Distro.IsOpenSUSE())
-    ExtraOpts.push_back("--enable-new-dtags");
-
-  // The selection of paths to try here is designed to match the patterns which
-  // the GCC driver itself uses, as this is part of the GCC-compatible driver.
-  // This was determined by running GCC in a fake filesystem, creating all
-  // possible permutations of these directories, and seeing which ones it added
-  // to the link paths.
-  path_list &Paths = getFilePaths();
-
-  const std::string OSLibDir = getOSLibDir(Triple, Args);
-  const std::string MultiarchTriple = getMultiarchTriple(D, Triple, SysRoot);
-
-  // Add the multilib suffixed paths where they are available.
-  if (GCCInstallation.isValid()) {
-    const llvm::Triple &GCCTriple = GCCInstallation.getTriple();
-    const std::string &LibPath = GCCInstallation.getParentLibPath();
-    const Multilib &Multilib = GCCInstallation.getMultilib();
-    const MultilibSet &Multilibs = GCCInstallation.getMultilibs();
-
-    // Add toolchain / multilib specific file paths.
-    addMultilibsFilePaths(D, Multilibs, Multilib,
-                          GCCInstallation.getInstallPath(), Paths);
-
-    // Sourcery CodeBench MIPS toolchain holds some libraries under
-    // a biarch-like suffix of the GCC installation.
-    addPathIfExists(D, GCCInstallation.getInstallPath() + Multilib.gccSuffix(),
-                    Paths);
-
-    // GCC cross compiling toolchains will install target libraries which ship
-    // as part of the toolchain under <prefix>/<triple>/<libdir> rather than as
-    // any part of the GCC installation in
-    // <prefix>/<libdir>/gcc/<triple>/<version>. This decision is somewhat
-    // debatable, but is the reality today. We need to search this tree even
-    // when we have a sysroot somewhere else. It is the responsibility of
-    // whomever is doing the cross build targeting a sysroot using a GCC
-    // installation that is *not* within the system root to ensure two things:
-    //
-    //  1) Any DSOs that are linked in from this tree or from the install path
-    //     above must be present on the system root and found via an
-    //     appropriate rpath.
-    //  2) There must not be libraries installed into
-    //     <prefix>/<triple>/<libdir> unless they should be preferred over
-    //     those within the system root.
-    //
-    // Note that this matches the GCC behavior. See the below comment for where
-    // Clang diverges from GCC's behavior.
-    addPathIfExists(D, LibPath + "/../" + GCCTriple.str() + "/lib/../" +
-                           OSLibDir + Multilib.osSuffix(),
-                    Paths);
-
-    // If the GCC installation we found is inside of the sysroot, we want to
-    // prefer libraries installed in the parent prefix of the GCC installation.
-    // It is important to *not* use these paths when the GCC installation is
-    // outside of the system root as that can pick up unintended libraries.
-    // This usually happens when there is an external cross compiler on the
-    // host system, and a more minimal sysroot available that is the target of
-    // the cross. Note that GCC does include some of these directories in some
-    // configurations but this seems somewhere between questionable and simply
-    // a bug.
-    if (StringRef(LibPath).startswith(SysRoot)) {
-      addPathIfExists(D, LibPath + "/" + MultiarchTriple, Paths);
-      addPathIfExists(D, LibPath + "/../" + OSLibDir, Paths);
-    }
-  }
-
-  // Similar to the logic for GCC above, if we currently running Clang inside
-  // of the requested system root, add its parent library paths to
-  // those searched.
-  // FIXME: It's not clear whether we should use the driver's installed
-  // directory ('Dir' below) or the ResourceDir.
-  if (StringRef(D.Dir).startswith(SysRoot)) {
-    addPathIfExists(D, D.Dir + "/../lib/" + MultiarchTriple, Paths);
-    addPathIfExists(D, D.Dir + "/../" + OSLibDir, Paths);
-  }
-
-  addPathIfExists(D, SysRoot + "/lib/" + MultiarchTriple, Paths);
-  addPathIfExists(D, SysRoot + "/lib/../" + OSLibDir, Paths);
-  addPathIfExists(D, SysRoot + "/usr/lib/" + MultiarchTriple, Paths);
-  addPathIfExists(D, SysRoot + "/usr/lib/../" + OSLibDir, Paths);
-
-  // Try walking via the GCC triple path in case of biarch or multiarch GCC
-  // installations with strange symlinks.
-  if (GCCInstallation.isValid()) {
-    addPathIfExists(D,
-                    SysRoot + "/usr/lib/" + GCCInstallation.getTriple().str() +
-                        "/../../" + OSLibDir,
-                    Paths);
-
-    // Add the 'other' biarch variant path
-    Multilib BiarchSibling;
-    if (GCCInstallation.getBiarchSibling(BiarchSibling)) {
-      addPathIfExists(D, GCCInstallation.getInstallPath() +
-                             BiarchSibling.gccSuffix(),
-                      Paths);
-    }
-
-    // See comments above on the multilib variant for details of why this is
-    // included even from outside the sysroot.
-    const std::string &LibPath = GCCInstallation.getParentLibPath();
-    const llvm::Triple &GCCTriple = GCCInstallation.getTriple();
-    const Multilib &Multilib = GCCInstallation.getMultilib();
-    addPathIfExists(D, LibPath + "/../" + GCCTriple.str() + "/lib" +
-                           Multilib.osSuffix(),
-                    Paths);
-
-    // See comments above on the multilib variant for details of why this is
-    // only included from within the sysroot.
-    if (StringRef(LibPath).startswith(SysRoot))
-      addPathIfExists(D, LibPath, Paths);
-  }
-
-  // Similar to the logic for GCC above, if we are currently running Clang
-  // inside of the requested system root, add its parent library path to those
-  // searched.
-  // FIXME: It's not clear whether we should use the driver's installed
-  // directory ('Dir' below) or the ResourceDir.
-  if (StringRef(D.Dir).startswith(SysRoot))
-    addPathIfExists(D, D.Dir + "/../lib", Paths);
-
-  addPathIfExists(D, SysRoot + "/lib", Paths);
-  addPathIfExists(D, SysRoot + "/usr/lib", Paths);
-}
-
-bool Linux::HasNativeLLVMSupport() const { return true; }
-
-Tool *Linux::buildLinker() const { return new tools::gnutools::Linker(*this); }
-
-Tool *Linux::buildAssembler() const {
-  return new tools::gnutools::Assembler(*this);
-}
-
-std::string Linux::computeSysRoot() const {
-  if (!getDriver().SysRoot.empty())
-    return getDriver().SysRoot;
-
-  if (!GCCInstallation.isValid() || !isMipsArch(getTriple().getArch()))
-    return std::string();
-
-  // Standalone MIPS toolchains use different names for sysroot folder
-  // and put it into different places. Here we try to check some known
-  // variants.
-
-  const StringRef InstallDir = GCCInstallation.getInstallPath();
-  const StringRef TripleStr = GCCInstallation.getTriple().str();
-  const Multilib &Multilib = GCCInstallation.getMultilib();
-
-  std::string Path =
-      (InstallDir + "/../../../../" + TripleStr + "/libc" + Multilib.osSuffix())
-          .str();
-
-  if (getVFS().exists(Path))
-    return Path;
-
-  Path = (InstallDir + "/../../../../sysroot" + Multilib.osSuffix()).str();
-
-  if (getVFS().exists(Path))
-    return Path;
-
-  return std::string();
-}
-
-std::string Linux::getDynamicLinker(const ArgList &Args) const {
-  const llvm::Triple::ArchType Arch = getArch();
-  const llvm::Triple &Triple = getTriple();
-
-  const Distro Distro(getDriver().getVFS());
-
-  if (Triple.isAndroid())
-    return Triple.isArch64Bit() ? "/system/bin/linker64" : "/system/bin/linker";
-
-  if (Triple.isMusl()) {
-    std::string ArchName;
-    bool IsArm = false;
-
-    switch (Arch) {
-    case llvm::Triple::arm:
-    case llvm::Triple::thumb:
-      ArchName = "arm";
-      IsArm = true;
-      break;
-    case llvm::Triple::armeb:
-    case llvm::Triple::thumbeb:
-      ArchName = "armeb";
-      IsArm = true;
-      break;
-    default:
-      ArchName = Triple.getArchName().str();
-    }
-    if (IsArm &&
-        (Triple.getEnvironment() == llvm::Triple::MuslEABIHF ||
-         tools::arm::getARMFloatABI(*this, Args) == tools::arm::FloatABI::Hard))
-      ArchName += "hf";
-
-    return "/lib/ld-musl-" + ArchName + ".so.1";
-  }
-
-  std::string LibDir;
-  std::string Loader;
-
-  switch (Arch) {
-  default:
-    llvm_unreachable("unsupported architecture");
-
-  case llvm::Triple::aarch64:
-    LibDir = "lib";
-    Loader = "ld-linux-aarch64.so.1";
-    break;
-  case llvm::Triple::aarch64_be:
-    LibDir = "lib";
-    Loader = "ld-linux-aarch64_be.so.1";
-    break;
-  case llvm::Triple::arm:
-  case llvm::Triple::thumb:
-  case llvm::Triple::armeb:
-  case llvm::Triple::thumbeb: {
-    const bool HF =
-        Triple.getEnvironment() == llvm::Triple::GNUEABIHF ||
-        tools::arm::getARMFloatABI(*this, Args) == tools::arm::FloatABI::Hard;
-
-    LibDir = "lib";
-    Loader = HF ? "ld-linux-armhf.so.3" : "ld-linux.so.3";
-    break;
-  }
-  case llvm::Triple::mips:
-  case llvm::Triple::mipsel:
-  case llvm::Triple::mips64:
-  case llvm::Triple::mips64el: {
-    bool LE = (Triple.getArch() == llvm::Triple::mipsel) ||
-              (Triple.getArch() == llvm::Triple::mips64el);
-    bool IsNaN2008 = tools::mips::isNaN2008(Args, Triple);
-
-    LibDir = "lib" + tools::mips::getMipsABILibSuffix(Args, Triple);
-
-    if (tools::mips::isUCLibc(Args))
-      Loader = IsNaN2008 ? "ld-uClibc-mipsn8.so.0" : "ld-uClibc.so.0";
-    else if (!Triple.hasEnvironment() &&
-             Triple.getVendor() == llvm::Triple::VendorType::MipsTechnologies)
-      Loader = LE ? "ld-musl-mipsel.so.1" : "ld-musl-mips.so.1";
-    else
-      Loader = IsNaN2008 ? "ld-linux-mipsn8.so.1" : "ld.so.1";
-
-    break;
-  }
-  case llvm::Triple::ppc:
-    LibDir = "lib";
-    Loader = "ld.so.1";
-    break;
-  case llvm::Triple::ppc64:
-    LibDir = "lib64";
-    Loader =
-        (tools::ppc::hasPPCAbiArg(Args, "elfv2")) ? "ld64.so.2" : "ld64.so.1";
-    break;
-  case llvm::Triple::ppc64le:
-    LibDir = "lib64";
-    Loader =
-        (tools::ppc::hasPPCAbiArg(Args, "elfv1")) ? "ld64.so.1" : "ld64.so.2";
-    break;
-  case llvm::Triple::sparc:
-  case llvm::Triple::sparcel:
-    LibDir = "lib";
-    Loader = "ld-linux.so.2";
-    break;
-  case llvm::Triple::sparcv9:
-    LibDir = "lib64";
-    Loader = "ld-linux.so.2";
-    break;
-  case llvm::Triple::systemz:
-    LibDir = "lib";
-    Loader = "ld64.so.1";
-    break;
-  case llvm::Triple::x86:
-    LibDir = "lib";
-    Loader = "ld-linux.so.2";
-    break;
-  case llvm::Triple::x86_64: {
-    bool X32 = Triple.getEnvironment() == llvm::Triple::GNUX32;
-
-    LibDir = X32 ? "libx32" : "lib64";
-    Loader = X32 ? "ld-linux-x32.so.2" : "ld-linux-x86-64.so.2";
-    break;
-  }
-  }
-
-  if (Distro == Distro::Exherbo && (Triple.getVendor() == llvm::Triple::UnknownVendor ||
-                                    Triple.getVendor() == llvm::Triple::PC))
-    return "/usr/" + Triple.str() + "/lib/" + Loader;
-  return "/" + LibDir + "/" + Loader;
-}
-
-void Linux::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
-                                      ArgStringList &CC1Args) const {
-  const Driver &D = getDriver();
-  std::string SysRoot = computeSysRoot();
-
-  if (DriverArgs.hasArg(options::OPT_nostdinc))
-    return;
-
-  if (!DriverArgs.hasArg(options::OPT_nostdlibinc))
-    addSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/local/include");
-
-  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
-    SmallString<128> P(D.ResourceDir);
-    llvm::sys::path::append(P, "include");
-    addSystemInclude(DriverArgs, CC1Args, P);
-  }
-
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
-    return;
-
-  // Check for configure-time C include directories.
-  StringRef CIncludeDirs(C_INCLUDE_DIRS);
-  if (CIncludeDirs != "") {
-    SmallVector<StringRef, 5> dirs;
-    CIncludeDirs.split(dirs, ":");
-    for (StringRef dir : dirs) {
-      StringRef Prefix =
-          llvm::sys::path::is_absolute(dir) ? StringRef(SysRoot) : "";
-      addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
-    }
-    return;
-  }
-
-  // Lacking those, try to detect the correct set of system includes for the
-  // target triple.
-
-  // Add include directories specific to the selected multilib set and multilib.
-  if (GCCInstallation.isValid()) {
-    const auto &Callback = Multilibs.includeDirsCallback();
-    if (Callback) {
-      for (const auto &Path : Callback(GCCInstallation.getMultilib()))
-        addExternCSystemIncludeIfExists(
-            DriverArgs, CC1Args, GCCInstallation.getInstallPath() + Path);
-    }
-  }
-
-  // Implement generic Debian multiarch support.
-  const StringRef X86_64MultiarchIncludeDirs[] = {
-      "/usr/include/x86_64-linux-gnu",
-
-      // FIXME: These are older forms of multiarch. It's not clear that they're
-      // in use in any released version of Debian, so we should consider
-      // removing them.
-      "/usr/include/i686-linux-gnu/64", "/usr/include/i486-linux-gnu/64"};
-  const StringRef X86MultiarchIncludeDirs[] = {
-      "/usr/include/i386-linux-gnu",
-
-      // FIXME: These are older forms of multiarch. It's not clear that they're
-      // in use in any released version of Debian, so we should consider
-      // removing them.
-      "/usr/include/x86_64-linux-gnu/32", "/usr/include/i686-linux-gnu",
-      "/usr/include/i486-linux-gnu"};
-  const StringRef AArch64MultiarchIncludeDirs[] = {
-      "/usr/include/aarch64-linux-gnu"};
-  const StringRef ARMMultiarchIncludeDirs[] = {
-      "/usr/include/arm-linux-gnueabi"};
-  const StringRef ARMHFMultiarchIncludeDirs[] = {
-      "/usr/include/arm-linux-gnueabihf"};
-  const StringRef ARMEBMultiarchIncludeDirs[] = {
-      "/usr/include/armeb-linux-gnueabi"};
-  const StringRef ARMEBHFMultiarchIncludeDirs[] = {
-      "/usr/include/armeb-linux-gnueabihf"};
-  const StringRef MIPSMultiarchIncludeDirs[] = {"/usr/include/mips-linux-gnu"};
-  const StringRef MIPSELMultiarchIncludeDirs[] = {
-      "/usr/include/mipsel-linux-gnu"};
-  const StringRef MIPS64MultiarchIncludeDirs[] = {
-      "/usr/include/mips64-linux-gnu", "/usr/include/mips64-linux-gnuabi64"};
-  const StringRef MIPS64ELMultiarchIncludeDirs[] = {
-      "/usr/include/mips64el-linux-gnu",
-      "/usr/include/mips64el-linux-gnuabi64"};
-  const StringRef PPCMultiarchIncludeDirs[] = {
-      "/usr/include/powerpc-linux-gnu"};
-  const StringRef PPC64MultiarchIncludeDirs[] = {
-      "/usr/include/powerpc64-linux-gnu"};
-  const StringRef PPC64LEMultiarchIncludeDirs[] = {
-      "/usr/include/powerpc64le-linux-gnu"};
-  const StringRef SparcMultiarchIncludeDirs[] = {
-      "/usr/include/sparc-linux-gnu"};
-  const StringRef Sparc64MultiarchIncludeDirs[] = {
-      "/usr/include/sparc64-linux-gnu"};
-  const StringRef SYSTEMZMultiarchIncludeDirs[] = {
-      "/usr/include/s390x-linux-gnu"};
-  ArrayRef<StringRef> MultiarchIncludeDirs;
-  switch (getTriple().getArch()) {
-  case llvm::Triple::x86_64:
-    MultiarchIncludeDirs = X86_64MultiarchIncludeDirs;
-    break;
-  case llvm::Triple::x86:
-    MultiarchIncludeDirs = X86MultiarchIncludeDirs;
-    break;
-  case llvm::Triple::aarch64:
-  case llvm::Triple::aarch64_be:
-    MultiarchIncludeDirs = AArch64MultiarchIncludeDirs;
-    break;
-  case llvm::Triple::arm:
-  case llvm::Triple::thumb:
-    if (getTriple().getEnvironment() == llvm::Triple::GNUEABIHF)
-      MultiarchIncludeDirs = ARMHFMultiarchIncludeDirs;
-    else
-      MultiarchIncludeDirs = ARMMultiarchIncludeDirs;
-    break;
-  case llvm::Triple::armeb:
-  case llvm::Triple::thumbeb:
-    if (getTriple().getEnvironment() == llvm::Triple::GNUEABIHF)
-      MultiarchIncludeDirs = ARMEBHFMultiarchIncludeDirs;
-    else
-      MultiarchIncludeDirs = ARMEBMultiarchIncludeDirs;
-    break;
-  case llvm::Triple::mips:
-    MultiarchIncludeDirs = MIPSMultiarchIncludeDirs;
-    break;
-  case llvm::Triple::mipsel:
-    MultiarchIncludeDirs = MIPSELMultiarchIncludeDirs;
-    break;
-  case llvm::Triple::mips64:
-    MultiarchIncludeDirs = MIPS64MultiarchIncludeDirs;
-    break;
-  case llvm::Triple::mips64el:
-    MultiarchIncludeDirs = MIPS64ELMultiarchIncludeDirs;
-    break;
-  case llvm::Triple::ppc:
-    MultiarchIncludeDirs = PPCMultiarchIncludeDirs;
-    break;
-  case llvm::Triple::ppc64:
-    MultiarchIncludeDirs = PPC64MultiarchIncludeDirs;
-    break;
-  case llvm::Triple::ppc64le:
-    MultiarchIncludeDirs = PPC64LEMultiarchIncludeDirs;
-    break;
-  case llvm::Triple::sparc:
-    MultiarchIncludeDirs = SparcMultiarchIncludeDirs;
-    break;
-  case llvm::Triple::sparcv9:
-    MultiarchIncludeDirs = Sparc64MultiarchIncludeDirs;
-    break;
-  case llvm::Triple::systemz:
-    MultiarchIncludeDirs = SYSTEMZMultiarchIncludeDirs;
-    break;
-  default:
-    break;
-  }
-  for (StringRef Dir : MultiarchIncludeDirs) {
-    if (D.getVFS().exists(SysRoot + Dir)) {
-      addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + Dir);
-      break;
-    }
-  }
-
-  if (getTriple().getOS() == llvm::Triple::RTEMS)
-    return;
-
-  // Add an include of '/include' directly. This isn't provided by default by
-  // system GCCs, but is often used with cross-compiling GCCs, and harmless to
-  // add even when Clang is acting as-if it were a system compiler.
-  addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/include");
-
-  addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include");
-}
-
-static std::string DetectLibcxxIncludePath(StringRef base) {
-  std::error_code EC;
-  int MaxVersion = 0;
-  std::string MaxVersionString = "";
-  for (llvm::sys::fs::directory_iterator LI(base, EC), LE; !EC && LI != LE;
-       LI = LI.increment(EC)) {
-    StringRef VersionText = llvm::sys::path::filename(LI->path());
-    int Version;
-    if (VersionText[0] == 'v' &&
-        !VersionText.slice(1, StringRef::npos).getAsInteger(10, Version)) {
-      if (Version > MaxVersion) {
-        MaxVersion = Version;
-        MaxVersionString = VersionText;
-      }
-    }
-  }
-  return MaxVersion ? (base + "/" + MaxVersionString).str() : "";
-}
-
-std::string Linux::findLibCxxIncludePath() const {
-  const std::string LibCXXIncludePathCandidates[] = {
-      DetectLibcxxIncludePath(getDriver().Dir + "/../include/c++"),
-      // If this is a development, non-installed, clang, libcxx will
-      // not be found at ../include/c++ but it likely to be found at
-      // one of the following two locations:
-      DetectLibcxxIncludePath(getDriver().SysRoot + "/usr/local/include/c++"),
-      DetectLibcxxIncludePath(getDriver().SysRoot + "/usr/include/c++") };
-  for (const auto &IncludePath : LibCXXIncludePathCandidates) {
-    if (IncludePath.empty() || !getVFS().exists(IncludePath))
-      continue;
-    // Use the first candidate that exists.
-    return IncludePath;
-  }
-  return "";
-}
-
-void Linux::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
-                                     llvm::opt::ArgStringList &CC1Args) const {
-  // We need a detected GCC installation on Linux to provide libstdc++'s
-  // headers.
-  if (!GCCInstallation.isValid())
-    return;
-
-  // By default, look for the C++ headers in an include directory adjacent to
-  // the lib directory of the GCC installation. Note that this is expect to be
-  // equivalent to '/usr/include/c++/X.Y' in almost all cases.
-  StringRef LibDir = GCCInstallation.getParentLibPath();
-  StringRef InstallDir = GCCInstallation.getInstallPath();
-  StringRef TripleStr = GCCInstallation.getTriple().str();
-  const Multilib &Multilib = GCCInstallation.getMultilib();
-  const std::string GCCMultiarchTriple = getMultiarchTriple(
-      getDriver(), GCCInstallation.getTriple(), getDriver().SysRoot);
-  const std::string TargetMultiarchTriple =
-      getMultiarchTriple(getDriver(), getTriple(), getDriver().SysRoot);
-  const GCCVersion &Version = GCCInstallation.getVersion();
-
-  // The primary search for libstdc++ supports multiarch variants.
-  if (addLibStdCXXIncludePaths(LibDir.str() + "/../include",
-                               "/c++/" + Version.Text, TripleStr,
-                               GCCMultiarchTriple, TargetMultiarchTriple,
-                               Multilib.includeSuffix(), DriverArgs, CC1Args))
-    return;
-
-  // Otherwise, fall back on a bunch of options which don't use multiarch
-  // layouts for simplicity.
-  const std::string LibStdCXXIncludePathCandidates[] = {
-      // Gentoo is weird and places its headers inside the GCC install,
-      // so if the first attempt to find the headers fails, try these patterns.
-      InstallDir.str() + "/include/g++-v" + Version.Text,
-      InstallDir.str() + "/include/g++-v" + Version.MajorStr + "." +
-          Version.MinorStr,
-      InstallDir.str() + "/include/g++-v" + Version.MajorStr,
-      // Android standalone toolchain has C++ headers in yet another place.
-      LibDir.str() + "/../" + TripleStr.str() + "/include/c++/" + Version.Text,
-      // Freescale SDK C++ headers are directly in <sysroot>/usr/include/c++,
-      // without a subdirectory corresponding to the gcc version.
-      LibDir.str() + "/../include/c++",
-  };
-
-  for (const auto &IncludePath : LibStdCXXIncludePathCandidates) {
-    if (addLibStdCXXIncludePaths(IncludePath, /*Suffix*/ "", TripleStr,
-                                 /*GCCMultiarchTriple*/ "",
-                                 /*TargetMultiarchTriple*/ "",
-                                 Multilib.includeSuffix(), DriverArgs, CC1Args))
-      break;
-  }
-}
-
-void Linux::AddCudaIncludeArgs(const ArgList &DriverArgs,
-                               ArgStringList &CC1Args) const {
-  CudaInstallation.AddCudaIncludeArgs(DriverArgs, CC1Args);
-}
-
-void Linux::AddIAMCUIncludeArgs(const ArgList &DriverArgs,
-                                ArgStringList &CC1Args) const {
-  if (GCCInstallation.isValid()) {
-    CC1Args.push_back("-isystem");
-    CC1Args.push_back(DriverArgs.MakeArgString(
-        GCCInstallation.getParentLibPath() + "/../" +
-        GCCInstallation.getTriple().str() + "/include"));
-  }
-}
-
-bool Linux::isPIEDefault() const { return getSanitizerArgs().requiresPIE(); }
-
-SanitizerMask Linux::getSupportedSanitizers() const {
-  const bool IsX86 = getTriple().getArch() == llvm::Triple::x86;
-  const bool IsX86_64 = getTriple().getArch() == llvm::Triple::x86_64;
-  const bool IsMIPS64 = getTriple().getArch() == llvm::Triple::mips64 ||
-                        getTriple().getArch() == llvm::Triple::mips64el;
-  const bool IsPowerPC64 = getTriple().getArch() == llvm::Triple::ppc64 ||
-                           getTriple().getArch() == llvm::Triple::ppc64le;
-  const bool IsAArch64 = getTriple().getArch() == llvm::Triple::aarch64 ||
-                         getTriple().getArch() == llvm::Triple::aarch64_be;
-  SanitizerMask Res = ToolChain::getSupportedSanitizers();
-  Res |= SanitizerKind::Address;
-  Res |= SanitizerKind::KernelAddress;
-  Res |= SanitizerKind::Vptr;
-  Res |= SanitizerKind::SafeStack;
-  if (IsX86_64 || IsMIPS64 || IsAArch64)
-    Res |= SanitizerKind::DataFlow;
-  if (IsX86_64 || IsMIPS64 || IsAArch64)
-    Res |= SanitizerKind::Leak;
-  if (IsX86_64 || IsMIPS64 || IsAArch64 || IsPowerPC64)
-    Res |= SanitizerKind::Thread;
-  if (IsX86_64 || IsMIPS64 || IsPowerPC64 || IsAArch64)
-    Res |= SanitizerKind::Memory;
-  if (IsX86_64 || IsMIPS64)
-    Res |= SanitizerKind::Efficiency;
-  if (IsX86 || IsX86_64) {
-    Res |= SanitizerKind::Function;
-  }
-  return Res;
-}
-
-void Linux::addProfileRTLibs(const llvm::opt::ArgList &Args,
-                             llvm::opt::ArgStringList &CmdArgs) const {
-  if (!needsProfileRT(Args)) return;
-
-  // Add linker option -u__llvm_runtime_variable to cause runtime
-  // initialization module to be linked in.
-  if (!Args.hasArg(options::OPT_coverage))
-    CmdArgs.push_back(Args.MakeArgString(
-        Twine("-u", llvm::getInstrProfRuntimeHookVarName())));
-  ToolChain::addProfileRTLibs(Args, CmdArgs);
-}
-
-/// Fuchsia - Fuchsia tool chain which can call as(1) and ld(1) directly.
-
-Fuchsia::Fuchsia(const Driver &D, const llvm::Triple &Triple,
-                 const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {
-
-  getFilePaths().push_back(D.SysRoot + "/lib");
-  getFilePaths().push_back(D.ResourceDir + "/lib/fuchsia");
-}
-
-Tool *Fuchsia::buildAssembler() const {
-  return new tools::gnutools::Assembler(*this);
-}
-
-Tool *Fuchsia::buildLinker() const {
-  return new tools::fuchsia::Linker(*this);
-}
-
-ToolChain::RuntimeLibType Fuchsia::GetRuntimeLibType(
-    const ArgList &Args) const {
-  if (Arg *A = Args.getLastArg(options::OPT_rtlib_EQ)) {
-    StringRef Value = A->getValue();
-    if (Value != "compiler-rt")
-      getDriver().Diag(diag::err_drv_invalid_rtlib_name)
-        << A->getAsString(Args);
-  }
-
-  return ToolChain::RLT_CompilerRT;
-}
-
-ToolChain::CXXStdlibType
-Fuchsia::GetCXXStdlibType(const ArgList &Args) const {
-  if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
-    StringRef Value = A->getValue();
-    if (Value != "libc++")
-      getDriver().Diag(diag::err_drv_invalid_stdlib_name)
-        << A->getAsString(Args);
-  }
-
-  return ToolChain::CST_Libcxx;
-}
-
-void Fuchsia::addClangTargetOptions(const ArgList &DriverArgs,
-                                    ArgStringList &CC1Args) const {
-  if (DriverArgs.hasFlag(options::OPT_fuse_init_array,
-                         options::OPT_fno_use_init_array, true))
-    CC1Args.push_back("-fuse-init-array");
-}
-
-void Fuchsia::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
-                                        ArgStringList &CC1Args) const {
-  const Driver &D = getDriver();
-
-  if (DriverArgs.hasArg(options::OPT_nostdinc))
-    return;
-
-  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
-    SmallString<128> P(D.ResourceDir);
-    llvm::sys::path::append(P, "include");
-    addSystemInclude(DriverArgs, CC1Args, P);
-  }
-
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
-    return;
-
-  // Check for configure-time C include directories.
-  StringRef CIncludeDirs(C_INCLUDE_DIRS);
-  if (CIncludeDirs != "") {
-    SmallVector<StringRef, 5> dirs;
-    CIncludeDirs.split(dirs, ":");
-    for (StringRef dir : dirs) {
-      StringRef Prefix =
-          llvm::sys::path::is_absolute(dir) ? StringRef(D.SysRoot) : "";
-      addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
-    }
-    return;
-  }
-
-  addExternCSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/include");
-}
-
-std::string Fuchsia::findLibCxxIncludePath() const {
-  return getDriver().SysRoot + "/include/c++/v1";
-}
-
-void Fuchsia::AddCXXStdlibLibArgs(const ArgList &Args,
-                                  ArgStringList &CmdArgs) const {
-  (void) GetCXXStdlibType(Args);
-  CmdArgs.push_back("-lc++");
-  CmdArgs.push_back("-lc++abi");
-  CmdArgs.push_back("-lunwind");
-}
-
-/// DragonFly - DragonFly tool chain which can call as(1) and ld(1) directly.
-
-DragonFly::DragonFly(const Driver &D, const llvm::Triple &Triple,
-                     const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {
-
-  // Path mangling to find libexec
-  getProgramPaths().push_back(getDriver().getInstalledDir());
-  if (getDriver().getInstalledDir() != getDriver().Dir)
-    getProgramPaths().push_back(getDriver().Dir);
-
-  getFilePaths().push_back(getDriver().Dir + "/../lib");
-  getFilePaths().push_back("/usr/lib");
-  getFilePaths().push_back("/usr/lib/gcc50");
-}
-
-Tool *DragonFly::buildAssembler() const {
-  return new tools::dragonfly::Assembler(*this);
-}
-
-Tool *DragonFly::buildLinker() const {
-  return new tools::dragonfly::Linker(*this);
-}
-
-/// CUDA toolchain.  Our assembler is ptxas, and our "linker" is fatbinary,
-/// which isn't properly a linker but nonetheless performs the step of stitching
-/// together object files from the assembler into a single blob.
-
-CudaToolChain::CudaToolChain(const Driver &D, const llvm::Triple &Triple,
-                             const ToolChain &HostTC, const ArgList &Args)
-    : ToolChain(D, Triple, Args), HostTC(HostTC),
-      CudaInstallation(D, HostTC.getTriple(), Args) {
-  if (CudaInstallation.isValid())
-    getProgramPaths().push_back(CudaInstallation.getBinPath());
-}
-
-void CudaToolChain::addClangTargetOptions(
-    const llvm::opt::ArgList &DriverArgs,
-    llvm::opt::ArgStringList &CC1Args) const {
-  HostTC.addClangTargetOptions(DriverArgs, CC1Args);
-
-  CC1Args.push_back("-fcuda-is-device");
-
-  if (DriverArgs.hasFlag(options::OPT_fcuda_flush_denormals_to_zero,
-                         options::OPT_fno_cuda_flush_denormals_to_zero, false))
-    CC1Args.push_back("-fcuda-flush-denormals-to-zero");
-
-  if (DriverArgs.hasFlag(options::OPT_fcuda_approx_transcendentals,
-                         options::OPT_fno_cuda_approx_transcendentals, false))
-    CC1Args.push_back("-fcuda-approx-transcendentals");
-
-  if (DriverArgs.hasArg(options::OPT_nocudalib))
-    return;
-
-  StringRef GpuArch = DriverArgs.getLastArgValue(options::OPT_march_EQ);
-  assert(!GpuArch.empty() && "Must have an explicit GPU arch.");
-  std::string LibDeviceFile = CudaInstallation.getLibDeviceFile(GpuArch);
-
-  if (LibDeviceFile.empty()) {
-    getDriver().Diag(diag::err_drv_no_cuda_libdevice) << GpuArch;
-    return;
-  }
-
-  CC1Args.push_back("-mlink-cuda-bitcode");
-  CC1Args.push_back(DriverArgs.MakeArgString(LibDeviceFile));
-
-  // Libdevice in CUDA-7.0 requires PTX version that's more recent
-  // than LLVM defaults to. Use PTX4.2 which is the PTX version that
-  // came with CUDA-7.0.
-  CC1Args.push_back("-target-feature");
-  CC1Args.push_back("+ptx42");
-}
-
-void CudaToolChain::AddCudaIncludeArgs(const ArgList &DriverArgs,
-                                       ArgStringList &CC1Args) const {
-  // Check our CUDA version if we're going to include the CUDA headers.
-  if (!DriverArgs.hasArg(options::OPT_nocudainc) &&
-      !DriverArgs.hasArg(options::OPT_no_cuda_version_check)) {
-    StringRef Arch = DriverArgs.getLastArgValue(options::OPT_march_EQ);
-    assert(!Arch.empty() && "Must have an explicit GPU arch.");
-    CudaInstallation.CheckCudaVersionSupportsArch(StringToCudaArch(Arch));
-  }
-  CudaInstallation.AddCudaIncludeArgs(DriverArgs, CC1Args);
-}
-
-llvm::opt::DerivedArgList *
-CudaToolChain::TranslateArgs(const llvm::opt::DerivedArgList &Args,
-                             StringRef BoundArch,
-                             Action::OffloadKind DeviceOffloadKind) const {
-  DerivedArgList *DAL =
-      HostTC.TranslateArgs(Args, BoundArch, DeviceOffloadKind);
-  if (!DAL)
-    DAL = new DerivedArgList(Args.getBaseArgs());
-
-  const OptTable &Opts = getDriver().getOpts();
-
-  for (Arg *A : Args) {
-    if (A->getOption().matches(options::OPT_Xarch__)) {
-      // Skip this argument unless the architecture matches BoundArch
-      if (BoundArch.empty() || A->getValue(0) != BoundArch)
-        continue;
-
-      unsigned Index = Args.getBaseArgs().MakeIndex(A->getValue(1));
-      unsigned Prev = Index;
-      std::unique_ptr<Arg> XarchArg(Opts.ParseOneArg(Args, Index));
-
-      // If the argument parsing failed or more than one argument was
-      // consumed, the -Xarch_ argument's parameter tried to consume
-      // extra arguments. Emit an error and ignore.
-      //
-      // We also want to disallow any options which would alter the
-      // driver behavior; that isn't going to work in our model. We
-      // use isDriverOption() as an approximation, although things
-      // like -O4 are going to slip through.
-      if (!XarchArg || Index > Prev + 1) {
-        getDriver().Diag(diag::err_drv_invalid_Xarch_argument_with_args)
-            << A->getAsString(Args);
-        continue;
-      } else if (XarchArg->getOption().hasFlag(options::DriverOption)) {
-        getDriver().Diag(diag::err_drv_invalid_Xarch_argument_isdriver)
-            << A->getAsString(Args);
-        continue;
-      }
-      XarchArg->setBaseArg(A);
-      A = XarchArg.release();
-      DAL->AddSynthesizedArg(A);
-    }
-    DAL->append(A);
-  }
-
-  if (!BoundArch.empty()) {
-    DAL->eraseArg(options::OPT_march_EQ);
-    DAL->AddJoinedArg(nullptr, Opts.getOption(options::OPT_march_EQ), BoundArch);
-  }
-  return DAL;
-}
-
-Tool *CudaToolChain::buildAssembler() const {
-  return new tools::NVPTX::Assembler(*this);
-}
-
-Tool *CudaToolChain::buildLinker() const {
-  return new tools::NVPTX::Linker(*this);
-}
-
-void CudaToolChain::addClangWarningOptions(ArgStringList &CC1Args) const {
-  HostTC.addClangWarningOptions(CC1Args);
-}
-
-ToolChain::CXXStdlibType
-CudaToolChain::GetCXXStdlibType(const ArgList &Args) const {
-  return HostTC.GetCXXStdlibType(Args);
-}
-
-void CudaToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
-                                              ArgStringList &CC1Args) const {
-  HostTC.AddClangSystemIncludeArgs(DriverArgs, CC1Args);
-}
-
-void CudaToolChain::AddClangCXXStdlibIncludeArgs(const ArgList &Args,
-                                                 ArgStringList &CC1Args) const {
-  HostTC.AddClangCXXStdlibIncludeArgs(Args, CC1Args);
-}
-
-void CudaToolChain::AddIAMCUIncludeArgs(const ArgList &Args,
-                                        ArgStringList &CC1Args) const {
-  HostTC.AddIAMCUIncludeArgs(Args, CC1Args);
-}
-
-SanitizerMask CudaToolChain::getSupportedSanitizers() const {
-  // The CudaToolChain only supports sanitizers in the sense that it allows
-  // sanitizer arguments on the command line if they are supported by the host
-  // toolchain. The CudaToolChain will actually ignore any command line
-  // arguments for any of these "supported" sanitizers. That means that no
-  // sanitization of device code is actually supported at this time.
-  //
-  // This behavior is necessary because the host and device toolchains
-  // invocations often share the command line, so the device toolchain must
-  // tolerate flags meant only for the host toolchain.
-  return HostTC.getSupportedSanitizers();
-}
-
-VersionTuple CudaToolChain::computeMSVCVersion(const Driver *D,
-                                               const ArgList &Args) const {
-  return HostTC.computeMSVCVersion(D, Args);
-}
-
-/// XCore tool chain
-XCoreToolChain::XCoreToolChain(const Driver &D, const llvm::Triple &Triple,
-                               const ArgList &Args)
-    : ToolChain(D, Triple, Args) {
-  // ProgramPaths are found via 'PATH' environment variable.
-}
-
-Tool *XCoreToolChain::buildAssembler() const {
-  return new tools::XCore::Assembler(*this);
-}
-
-Tool *XCoreToolChain::buildLinker() const {
-  return new tools::XCore::Linker(*this);
-}
-
-bool XCoreToolChain::isPICDefault() const { return false; }
-
-bool XCoreToolChain::isPIEDefault() const { return false; }
-
-bool XCoreToolChain::isPICDefaultForced() const { return false; }
-
-bool XCoreToolChain::SupportsProfiling() const { return false; }
-
-bool XCoreToolChain::hasBlocksRuntime() const { return false; }
-
-void XCoreToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
-                                               ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdinc) ||
-      DriverArgs.hasArg(options::OPT_nostdlibinc))
-    return;
-  if (const char *cl_include_dir = getenv("XCC_C_INCLUDE_PATH")) {
-    SmallVector<StringRef, 4> Dirs;
-    const char EnvPathSeparatorStr[] = {llvm::sys::EnvPathSeparator, '\0'};
-    StringRef(cl_include_dir).split(Dirs, StringRef(EnvPathSeparatorStr));
-    ArrayRef<StringRef> DirVec(Dirs);
-    addSystemIncludes(DriverArgs, CC1Args, DirVec);
-  }
-}
-
-void XCoreToolChain::addClangTargetOptions(const ArgList &DriverArgs,
-                                           ArgStringList &CC1Args) const {
-  CC1Args.push_back("-nostdsysteminc");
-}
-
-void XCoreToolChain::AddClangCXXStdlibIncludeArgs(
-    const ArgList &DriverArgs, ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdinc) ||
-      DriverArgs.hasArg(options::OPT_nostdlibinc) ||
-      DriverArgs.hasArg(options::OPT_nostdincxx))
-    return;
-  if (const char *cl_include_dir = getenv("XCC_CPLUS_INCLUDE_PATH")) {
-    SmallVector<StringRef, 4> Dirs;
-    const char EnvPathSeparatorStr[] = {llvm::sys::EnvPathSeparator, '\0'};
-    StringRef(cl_include_dir).split(Dirs, StringRef(EnvPathSeparatorStr));
-    ArrayRef<StringRef> DirVec(Dirs);
-    addSystemIncludes(DriverArgs, CC1Args, DirVec);
-  }
-}
-
-void XCoreToolChain::AddCXXStdlibLibArgs(const ArgList &Args,
-                                         ArgStringList &CmdArgs) const {
-  // We don't output any lib args. This is handled by xcc.
-}
-
-MyriadToolChain::MyriadToolChain(const Driver &D, const llvm::Triple &Triple,
-                                 const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {
-  // If a target of 'sparc-myriad-elf' is specified to clang, it wants to use
-  // 'sparc-myriad--elf' (note the unknown OS) as the canonical triple.
-  // This won't work to find gcc. Instead we give the installation detector an
-  // extra triple, which is preferable to further hacks of the logic that at
-  // present is based solely on getArch(). In particular, it would be wrong to
-  // choose the myriad installation when targeting a non-myriad sparc install.
-  switch (Triple.getArch()) {
-  default:
-    D.Diag(diag::err_target_unsupported_arch) << Triple.getArchName()
-                                              << "myriad";
-  case llvm::Triple::sparc:
-  case llvm::Triple::sparcel:
-  case llvm::Triple::shave:
-    GCCInstallation.init(Triple, Args, {"sparc-myriad-elf"});
-  }
-
-  if (GCCInstallation.isValid()) {
-    // This directory contains crt{i,n,begin,end}.o as well as libgcc.
-    // These files are tied to a particular version of gcc.
-    SmallString<128> CompilerSupportDir(GCCInstallation.getInstallPath());
-    addPathIfExists(D, CompilerSupportDir, getFilePaths());
-  }
-  // libstd++ and libc++ must both be found in this one place.
-  addPathIfExists(D, D.Dir + "/../sparc-myriad-elf/lib", getFilePaths());
-}
-
-MyriadToolChain::~MyriadToolChain() {}
-
-void MyriadToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
-                                                ArgStringList &CC1Args) const {
-  if (!DriverArgs.hasArg(options::OPT_nostdinc))
-    addSystemInclude(DriverArgs, CC1Args, getDriver().SysRoot + "/include");
-}
-
-std::string MyriadToolChain::findLibCxxIncludePath() const {
-  std::string Path(getDriver().getInstalledDir());
-  return Path + "/../include/c++/v1";
-}
-
-void MyriadToolChain::addLibStdCxxIncludePaths(
-    const llvm::opt::ArgList &DriverArgs,
-    llvm::opt::ArgStringList &CC1Args) const {
-  StringRef LibDir = GCCInstallation.getParentLibPath();
-  const GCCVersion &Version = GCCInstallation.getVersion();
-  StringRef TripleStr = GCCInstallation.getTriple().str();
-  const Multilib &Multilib = GCCInstallation.getMultilib();
-  addLibStdCXXIncludePaths(
-      LibDir.str() + "/../" + TripleStr.str() + "/include/c++/" + Version.Text,
-      "", TripleStr, "", "", Multilib.includeSuffix(), DriverArgs, CC1Args);
-}
-
-// MyriadToolChain handles several triples:
-//  {shave,sparc{,el}}-myriad-{rtems,unknown}-elf
-Tool *MyriadToolChain::SelectTool(const JobAction &JA) const {
-  // The inherited method works fine if not targeting the SHAVE.
-  if (!isShaveCompilation(getTriple()))
-    return ToolChain::SelectTool(JA);
-  switch (JA.getKind()) {
-  case Action::PreprocessJobClass:
-  case Action::CompileJobClass:
-    if (!Compiler)
-      Compiler.reset(new tools::SHAVE::Compiler(*this));
-    return Compiler.get();
-  case Action::AssembleJobClass:
-    if (!Assembler)
-      Assembler.reset(new tools::SHAVE::Assembler(*this));
-    return Assembler.get();
-  default:
-    return ToolChain::getTool(JA.getKind());
-  }
-}
-
-Tool *MyriadToolChain::buildLinker() const {
-  return new tools::Myriad::Linker(*this);
-}
-
-SanitizerMask MyriadToolChain::getSupportedSanitizers() const {
-  return SanitizerKind::Address;
-}
-
-WebAssembly::WebAssembly(const Driver &D, const llvm::Triple &Triple,
-                         const llvm::opt::ArgList &Args)
-  : ToolChain(D, Triple, Args) {
-
-  assert(Triple.isArch32Bit() != Triple.isArch64Bit());
-  getFilePaths().push_back(
-      getDriver().SysRoot + "/lib" + (Triple.isArch32Bit() ? "32" : "64"));
-}
-
-bool WebAssembly::IsMathErrnoDefault() const { return false; }
-
-bool WebAssembly::IsObjCNonFragileABIDefault() const { return true; }
-
-bool WebAssembly::UseObjCMixedDispatch() const { return true; }
-
-bool WebAssembly::isPICDefault() const { return false; }
-
-bool WebAssembly::isPIEDefault() const { return false; }
-
-bool WebAssembly::isPICDefaultForced() const { return false; }
-
-bool WebAssembly::IsIntegratedAssemblerDefault() const { return true; }
-
-// TODO: Support Objective C stuff.
-bool WebAssembly::SupportsObjCGC() const { return false; }
-
-bool WebAssembly::hasBlocksRuntime() const { return false; }
-
-// TODO: Support profiling.
-bool WebAssembly::SupportsProfiling() const { return false; }
-
-bool WebAssembly::HasNativeLLVMSupport() const { return true; }
-
-void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
-                                        ArgStringList &CC1Args) const {
-  if (DriverArgs.hasFlag(options::OPT_fuse_init_array,
-                         options::OPT_fno_use_init_array, true))
-    CC1Args.push_back("-fuse-init-array");
-}
-
-ToolChain::RuntimeLibType WebAssembly::GetDefaultRuntimeLibType() const {
-  return ToolChain::RLT_CompilerRT;
-}
-
-ToolChain::CXXStdlibType WebAssembly::GetCXXStdlibType(const ArgList &Args) const {
-  return ToolChain::CST_Libcxx;
-}
-
-void WebAssembly::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
-                                            ArgStringList &CC1Args) const {
-  if (!DriverArgs.hasArg(options::OPT_nostdinc))
-    addSystemInclude(DriverArgs, CC1Args, getDriver().SysRoot + "/include");
-}
-
-void WebAssembly::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
-                                               ArgStringList &CC1Args) const {
-  if (!DriverArgs.hasArg(options::OPT_nostdlibinc) &&
-      !DriverArgs.hasArg(options::OPT_nostdincxx))
-    addSystemInclude(DriverArgs, CC1Args,
-                     getDriver().SysRoot + "/include/c++/v1");
-}
-
-Tool *WebAssembly::buildLinker() const {
-  return new tools::wasm::Linker(*this);
-}
-
-PS4CPU::PS4CPU(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {
-  if (Args.hasArg(options::OPT_static))
-    D.Diag(diag::err_drv_unsupported_opt_for_target) << "-static" << "PS4";
-
-  // Determine where to find the PS4 libraries. We use SCE_ORBIS_SDK_DIR
-  // if it exists; otherwise use the driver's installation path, which
-  // should be <SDK_DIR>/host_tools/bin.
-
-  SmallString<512> PS4SDKDir;
-  if (const char *EnvValue = getenv("SCE_ORBIS_SDK_DIR")) {
-    if (!llvm::sys::fs::exists(EnvValue))
-      getDriver().Diag(clang::diag::warn_drv_ps4_sdk_dir) << EnvValue;
-    PS4SDKDir = EnvValue;
-  } else {
-    PS4SDKDir = getDriver().Dir;
-    llvm::sys::path::append(PS4SDKDir, "/../../");
-  }
-
-  // By default, the driver won't report a warning if it can't find
-  // PS4's include or lib directories. This behavior could be changed if
-  // -Weverything or -Winvalid-or-nonexistent-directory options are passed.
-  // If -isysroot was passed, use that as the SDK base path.
-  std::string PrefixDir;
-  if (const Arg *A = Args.getLastArg(options::OPT_isysroot)) {
-    PrefixDir = A->getValue();
-    if (!llvm::sys::fs::exists(PrefixDir))
-      getDriver().Diag(clang::diag::warn_missing_sysroot) << PrefixDir;
-  } else
-    PrefixDir = PS4SDKDir.str();
-
-  SmallString<512> PS4SDKIncludeDir(PrefixDir);
-  llvm::sys::path::append(PS4SDKIncludeDir, "target/include");
-  if (!Args.hasArg(options::OPT_nostdinc) &&
-      !Args.hasArg(options::OPT_nostdlibinc) &&
-      !Args.hasArg(options::OPT_isysroot) &&
-      !Args.hasArg(options::OPT__sysroot_EQ) &&
-      !llvm::sys::fs::exists(PS4SDKIncludeDir)) {
-    getDriver().Diag(clang::diag::warn_drv_unable_to_find_directory_expected)
-        << "PS4 system headers" << PS4SDKIncludeDir;
-  }
-
-  SmallString<512> PS4SDKLibDir(PS4SDKDir);
-  llvm::sys::path::append(PS4SDKLibDir, "target/lib");
-  if (!Args.hasArg(options::OPT_nostdlib) &&
-      !Args.hasArg(options::OPT_nodefaultlibs) &&
-      !Args.hasArg(options::OPT__sysroot_EQ) && !Args.hasArg(options::OPT_E) &&
-      !Args.hasArg(options::OPT_c) && !Args.hasArg(options::OPT_S) &&
-      !Args.hasArg(options::OPT_emit_ast) &&
-      !llvm::sys::fs::exists(PS4SDKLibDir)) {
-    getDriver().Diag(clang::diag::warn_drv_unable_to_find_directory_expected)
-        << "PS4 system libraries" << PS4SDKLibDir;
-    return;
-  }
-  getFilePaths().push_back(PS4SDKLibDir.str());
-}
-
-Tool *PS4CPU::buildAssembler() const {
-  return new tools::PS4cpu::Assemble(*this);
-}
-
-Tool *PS4CPU::buildLinker() const { return new tools::PS4cpu::Link(*this); }
-
-bool PS4CPU::isPICDefault() const { return true; }
-
-bool PS4CPU::HasNativeLLVMSupport() const { return true; }
-
-SanitizerMask PS4CPU::getSupportedSanitizers() const {
-  SanitizerMask Res = ToolChain::getSupportedSanitizers();
-  Res |= SanitizerKind::Address;
-  Res |= SanitizerKind::Vptr;
-  return Res;
-}
-
-Contiki::Contiki(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
-    : Generic_ELF(D, Triple, Args) {}
-
-SanitizerMask Contiki::getSupportedSanitizers() const {
-  const bool IsX86 = getTriple().getArch() == llvm::Triple::x86;
-  SanitizerMask Res = ToolChain::getSupportedSanitizers();
-  if (IsX86)
-    Res |= SanitizerKind::SafeStack;
-  return Res;
-}
-
-/// AVR Toolchain
-AVRToolChain::AVRToolChain(const Driver &D, const llvm::Triple &Triple,
-                           const ArgList &Args)
-  : Generic_ELF(D, Triple, Args) { }
-Tool *AVRToolChain::buildLinker() const {
-  return new tools::AVR::Linker(*this);
-}
-// End AVR
diff --git a/lib/Driver/ToolChains.h b/lib/Driver/ToolChains.h
deleted file mode 100644
index 3240357ba6b1..000000000000
--- a/lib/Driver/ToolChains.h
+++ /dev/null
@@ -1,1388 +0,0 @@
-//===--- ToolChains.h - ToolChain Implementations ---------------*- C++ -*-===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_H
-#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_H
-
-#include "Tools.h"
-#include "clang/Basic/Cuda.h"
-#include "clang/Basic/VersionTuple.h"
-#include "clang/Driver/Action.h"
-#include "clang/Driver/Multilib.h"
-#include "clang/Driver/ToolChain.h"
-#include "llvm/ADT/Optional.h"
-#include "llvm/ADT/SmallSet.h"
-#include "llvm/Support/Compiler.h"
-#include <set>
-#include <vector>
-
-namespace clang {
-namespace driver {
-
-/// A class to find a viable CUDA installation
-class CudaInstallationDetector {
-private:
-  const Driver &D;
-  bool IsValid = false;
-  CudaVersion Version = CudaVersion::UNKNOWN;
-  std::string InstallPath;
-  std::string BinPath;
-  std::string LibPath;
-  std::string LibDevicePath;
-  std::string IncludePath;
-  llvm::StringMap<std::string> LibDeviceMap;
-
-  // CUDA architectures for which we have raised an error in
-  // CheckCudaVersionSupportsArch.
-  mutable llvm::SmallSet<CudaArch, 4> ArchsWithVersionTooLowErrors;
-
-public:
-  CudaInstallationDetector(const Driver &D, const llvm::Triple &HostTriple,
-                           const llvm::opt::ArgList &Args);
-
-  void AddCudaIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                          llvm::opt::ArgStringList &CC1Args) const;
-
-  /// \brief Emit an error if Version does not support the given Arch.
-  ///
-  /// If either Version or Arch is unknown, does not emit an error.  Emits at
-  /// most one error per Arch.
-  void CheckCudaVersionSupportsArch(CudaArch Arch) const;
-
-  /// \brief Check whether we detected a valid Cuda install.
-  bool isValid() const { return IsValid; }
-  /// \brief Print information about the detected CUDA installation.
-  void print(raw_ostream &OS) const;
-
-  /// \brief Get the detected Cuda install's version.
-  CudaVersion version() const { return Version; }
-  /// \brief Get the detected Cuda installation path.
-  StringRef getInstallPath() const { return InstallPath; }
-  /// \brief Get the detected path to Cuda's bin directory.
-  StringRef getBinPath() const { return BinPath; }
-  /// \brief Get the detected Cuda Include path.
-  StringRef getIncludePath() const { return IncludePath; }
-  /// \brief Get the detected Cuda library path.
-  StringRef getLibPath() const { return LibPath; }
-  /// \brief Get the detected Cuda device library path.
-  StringRef getLibDevicePath() const { return LibDevicePath; }
-  /// \brief Get libdevice file for given architecture
-  std::string getLibDeviceFile(StringRef Gpu) const {
-    return LibDeviceMap.lookup(Gpu);
-  }
-};
-
-namespace toolchains {
-
-/// Generic_GCC - A tool chain using the 'gcc' command to perform
-/// all subcommands; this relies on gcc translating the majority of
-/// command line options.
-class LLVM_LIBRARY_VISIBILITY Generic_GCC : public ToolChain {
-public:
-  /// \brief Struct to store and manipulate GCC versions.
-  ///
-  /// We rely on assumptions about the form and structure of GCC version
-  /// numbers: they consist of at most three '.'-separated components, and each
-  /// component is a non-negative integer except for the last component. For
-  /// the last component we are very flexible in order to tolerate release
-  /// candidates or 'x' wildcards.
-  ///
-  /// Note that the ordering established among GCCVersions is based on the
-  /// preferred version string to use. For example we prefer versions without
-  /// a hard-coded patch number to those with a hard coded patch number.
-  ///
-  /// Currently this doesn't provide any logic for textual suffixes to patches
-  /// in the way that (for example) Debian's version format does. If that ever
-  /// becomes necessary, it can be added.
-  struct GCCVersion {
-    /// \brief The unparsed text of the version.
-    std::string Text;
-
-    /// \brief The parsed major, minor, and patch numbers.
-    int Major, Minor, Patch;
-
-    /// \brief The text of the parsed major, and major+minor versions.
-    std::string MajorStr, MinorStr;
-
-    /// \brief Any textual suffix on the patch number.
-    std::string PatchSuffix;
-
-    static GCCVersion Parse(StringRef VersionText);
-    bool isOlderThan(int RHSMajor, int RHSMinor, int RHSPatch,
-                     StringRef RHSPatchSuffix = StringRef()) const;
-    bool operator<(const GCCVersion &RHS) const {
-      return isOlderThan(RHS.Major, RHS.Minor, RHS.Patch, RHS.PatchSuffix);
-    }
-    bool operator>(const GCCVersion &RHS) const { return RHS < *this; }
-    bool operator<=(const GCCVersion &RHS) const { return !(*this > RHS); }
-    bool operator>=(const GCCVersion &RHS) const { return !(*this < RHS); }
-  };
-
-  /// \brief This is a class to find a viable GCC installation for Clang to
-  /// use.
-  ///
-  /// This class tries to find a GCC installation on the system, and report
-  /// information about it. It starts from the host information provided to the
-  /// Driver, and has logic for fuzzing that where appropriate.
-  class GCCInstallationDetector {
-    bool IsValid;
-    llvm::Triple GCCTriple;
-    const Driver &D;
-
-    // FIXME: These might be better as path objects.
-    std::string GCCInstallPath;
-    std::string GCCParentLibPath;
-
-    /// The primary multilib appropriate for the given flags.
-    Multilib SelectedMultilib;
-    /// On Biarch systems, this corresponds to the default multilib when
-    /// targeting the non-default multilib. Otherwise, it is empty.
-    llvm::Optional<Multilib> BiarchSibling;
-
-    GCCVersion Version;
-
-    // We retain the list of install paths that were considered and rejected in
-    // order to print out detailed information in verbose mode.
-    std::set<std::string> CandidateGCCInstallPaths;
-
-    /// The set of multilibs that the detected installation supports.
-    MultilibSet Multilibs;
-
-  public:
-    explicit GCCInstallationDetector(const Driver &D) : IsValid(false), D(D) {}
-    void init(const llvm::Triple &TargetTriple, const llvm::opt::ArgList &Args,
-              ArrayRef<std::string> ExtraTripleAliases = None);
-
-    /// \brief Check whether we detected a valid GCC install.
-    bool isValid() const { return IsValid; }
-
-    /// \brief Get the GCC triple for the detected install.
-    const llvm::Triple &getTriple() const { return GCCTriple; }
-
-    /// \brief Get the detected GCC installation path.
-    StringRef getInstallPath() const { return GCCInstallPath; }
-
-    /// \brief Get the detected GCC parent lib path.
-    StringRef getParentLibPath() const { return GCCParentLibPath; }
-
-    /// \brief Get the detected Multilib
-    const Multilib &getMultilib() const { return SelectedMultilib; }
-
-    /// \brief Get the whole MultilibSet
-    const MultilibSet &getMultilibs() const { return Multilibs; }
-
-    /// Get the biarch sibling multilib (if it exists).
-    /// \return true iff such a sibling exists
-    bool getBiarchSibling(Multilib &M) const;
-
-    /// \brief Get the detected GCC version string.
-    const GCCVersion &getVersion() const { return Version; }
-
-    /// \brief Print information about the detected GCC installation.
-    void print(raw_ostream &OS) const;
-
-  private:
-    static void
-    CollectLibDirsAndTriples(const llvm::Triple &TargetTriple,
-                             const llvm::Triple &BiarchTriple,
-                             SmallVectorImpl<StringRef> &LibDirs,
-                             SmallVectorImpl<StringRef> &TripleAliases,
-                             SmallVectorImpl<StringRef> &BiarchLibDirs,
-                             SmallVectorImpl<StringRef> &BiarchTripleAliases);
-
-    bool ScanGCCForMultilibs(const llvm::Triple &TargetTriple,
-                             const llvm::opt::ArgList &Args,
-                             StringRef Path,
-                             bool NeedsBiarchSuffix = false);
-
-    void ScanLibDirForGCCTriple(const llvm::Triple &TargetArch,
-                                const llvm::opt::ArgList &Args,
-                                const std::string &LibDir,
-                                StringRef CandidateTriple,
-                                bool NeedsBiarchSuffix = false);
-
-    void scanLibDirForGCCTripleSolaris(const llvm::Triple &TargetArch,
-                                       const llvm::opt::ArgList &Args,
-                                       const std::string &LibDir,
-                                       StringRef CandidateTriple,
-                                       bool NeedsBiarchSuffix = false);
-
-    bool ScanGentooGccConfig(const llvm::Triple &TargetTriple,
-                             const llvm::opt::ArgList &Args,
-                             StringRef CandidateTriple,
-                             bool NeedsBiarchSuffix = false);
-  };
-
-protected:
-  GCCInstallationDetector GCCInstallation;
-  CudaInstallationDetector CudaInstallation;
-
-public:
-  Generic_GCC(const Driver &D, const llvm::Triple &Triple,
-              const llvm::opt::ArgList &Args);
-  ~Generic_GCC() override;
-
-  void printVerboseInfo(raw_ostream &OS) const override;
-
-  bool IsUnwindTablesDefault() const override;
-  bool isPICDefault() const override;
-  bool isPIEDefault() const override;
-  bool isPICDefaultForced() const override;
-  bool IsIntegratedAssemblerDefault() const override;
-  llvm::opt::DerivedArgList *
-  TranslateArgs(const llvm::opt::DerivedArgList &Args, StringRef BoundArch,
-                Action::OffloadKind DeviceOffloadKind) const override;
-
-protected:
-  Tool *getTool(Action::ActionClass AC) const override;
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-
-  /// \name ToolChain Implementation Helper Functions
-  /// @{
-
-  /// \brief Check whether the target triple's architecture is 64-bits.
-  bool isTarget64Bit() const { return getTriple().isArch64Bit(); }
-
-  /// \brief Check whether the target triple's architecture is 32-bits.
-  bool isTarget32Bit() const { return getTriple().isArch32Bit(); }
-
-  // FIXME: This should be final, but the Solaris tool chain does weird
-  // things we can't easily represent.
-  void AddClangCXXStdlibIncludeArgs(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-
-  virtual std::string findLibCxxIncludePath() const;
-  virtual void
-  addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
-                           llvm::opt::ArgStringList &CC1Args) const;
-
-  bool addLibStdCXXIncludePaths(Twine Base, Twine Suffix, StringRef GCCTriple,
-                                StringRef GCCMultiarchTriple,
-                                StringRef TargetMultiarchTriple,
-                                Twine IncludeSuffix,
-                                const llvm::opt::ArgList &DriverArgs,
-                                llvm::opt::ArgStringList &CC1Args) const;
-
-  /// @}
-
-private:
-  mutable std::unique_ptr<tools::gcc::Preprocessor> Preprocess;
-  mutable std::unique_ptr<tools::gcc::Compiler> Compile;
-};
-
-class LLVM_LIBRARY_VISIBILITY MachO : public ToolChain {
-protected:
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-  Tool *getTool(Action::ActionClass AC) const override;
-
-private:
-  mutable std::unique_ptr<tools::darwin::Lipo> Lipo;
-  mutable std::unique_ptr<tools::darwin::Dsymutil> Dsymutil;
-  mutable std::unique_ptr<tools::darwin::VerifyDebug> VerifyDebug;
-
-public:
-  MachO(const Driver &D, const llvm::Triple &Triple,
-        const llvm::opt::ArgList &Args);
-  ~MachO() override;
-
-  /// @name MachO specific toolchain API
-  /// {
-
-  /// Get the "MachO" arch name for a particular compiler invocation. For
-  /// example, Apple treats different ARM variations as distinct architectures.
-  StringRef getMachOArchName(const llvm::opt::ArgList &Args) const;
-
-  /// Add the linker arguments to link the ARC runtime library.
-  virtual void AddLinkARCArgs(const llvm::opt::ArgList &Args,
-                              llvm::opt::ArgStringList &CmdArgs) const {}
-
-  /// Add the linker arguments to link the compiler runtime library.
-  virtual void AddLinkRuntimeLibArgs(const llvm::opt::ArgList &Args,
-                                     llvm::opt::ArgStringList &CmdArgs) const;
-
-  virtual void addStartObjectFileArgs(const llvm::opt::ArgList &Args,
-                                      llvm::opt::ArgStringList &CmdArgs) const {
-  }
-
-  virtual void addMinVersionArgs(const llvm::opt::ArgList &Args,
-                                 llvm::opt::ArgStringList &CmdArgs) const {}
-
-  /// On some iOS platforms, kernel and kernel modules were built statically. Is
-  /// this such a target?
-  virtual bool isKernelStatic() const { return false; }
-
-  /// Is the target either iOS or an iOS simulator?
-  bool isTargetIOSBased() const { return false; }
-
-  void AddLinkRuntimeLib(const llvm::opt::ArgList &Args,
-                         llvm::opt::ArgStringList &CmdArgs,
-                         StringRef DarwinLibName, bool AlwaysLink = false,
-                         bool IsEmbedded = false, bool AddRPath = false) const;
-
-  /// Add any profiling runtime libraries that are needed. This is essentially a
-  /// MachO specific version of addProfileRT in Tools.cpp.
-  void addProfileRTLibs(const llvm::opt::ArgList &Args,
-                        llvm::opt::ArgStringList &CmdArgs) const override {
-    // There aren't any profiling libs for embedded targets currently.
-  }
-
-  /// }
-  /// @name ToolChain Implementation
-  /// {
-
-  types::ID LookupTypeForExtension(StringRef Ext) const override;
-
-  bool HasNativeLLVMSupport() const override;
-
-  llvm::opt::DerivedArgList *
-  TranslateArgs(const llvm::opt::DerivedArgList &Args, StringRef BoundArch,
-                Action::OffloadKind DeviceOffloadKind) const override;
-
-  bool IsBlocksDefault() const override {
-    // Always allow blocks on Apple; users interested in versioning are
-    // expected to use /usr/include/Block.h.
-    return true;
-  }
-  bool IsIntegratedAssemblerDefault() const override {
-    // Default integrated assembler to on for Apple's MachO targets.
-    return true;
-  }
-
-  bool IsMathErrnoDefault() const override { return false; }
-
-  bool IsEncodeExtendedBlockSignatureDefault() const override { return true; }
-
-  bool IsObjCNonFragileABIDefault() const override {
-    // Non-fragile ABI is default for everything but i386.
-    return getTriple().getArch() != llvm::Triple::x86;
-  }
-
-  bool UseObjCMixedDispatch() const override { return true; }
-
-  bool IsUnwindTablesDefault() const override;
-
-  RuntimeLibType GetDefaultRuntimeLibType() const override {
-    return ToolChain::RLT_CompilerRT;
-  }
-
-  bool isPICDefault() const override;
-  bool isPIEDefault() const override;
-  bool isPICDefaultForced() const override;
-
-  bool SupportsProfiling() const override;
-
-  bool SupportsObjCGC() const override { return false; }
-
-  bool UseDwarfDebugFlags() const override;
-
-  bool UseSjLjExceptions(const llvm::opt::ArgList &Args) const override {
-    return false;
-  }
-
-  /// }
-};
-
-/// Darwin - The base Darwin tool chain.
-class LLVM_LIBRARY_VISIBILITY Darwin : public MachO {
-public:
-  /// Whether the information on the target has been initialized.
-  //
-  // FIXME: This should be eliminated. What we want to do is make this part of
-  // the "default target for arguments" selection process, once we get out of
-  // the argument translation business.
-  mutable bool TargetInitialized;
-
-  enum DarwinPlatformKind {
-    MacOS,
-    IPhoneOS,
-    IPhoneOSSimulator,
-    TvOS,
-    TvOSSimulator,
-    WatchOS,
-    WatchOSSimulator
-  };
-
-  mutable DarwinPlatformKind TargetPlatform;
-
-  /// The OS version we are targeting.
-  mutable VersionTuple TargetVersion;
-
-  CudaInstallationDetector CudaInstallation;
-
-private:
-  void AddDeploymentTarget(llvm::opt::DerivedArgList &Args) const;
-
-public:
-  Darwin(const Driver &D, const llvm::Triple &Triple,
-         const llvm::opt::ArgList &Args);
-  ~Darwin() override;
-
-  std::string ComputeEffectiveClangTriple(const llvm::opt::ArgList &Args,
-                                          types::ID InputType) const override;
-
-  /// @name Apple Specific Toolchain Implementation
-  /// {
-
-  void addMinVersionArgs(const llvm::opt::ArgList &Args,
-                         llvm::opt::ArgStringList &CmdArgs) const override;
-
-  void addStartObjectFileArgs(const llvm::opt::ArgList &Args,
-                              llvm::opt::ArgStringList &CmdArgs) const override;
-
-  bool isKernelStatic() const override {
-    return (!(isTargetIPhoneOS() && !isIPhoneOSVersionLT(6, 0)) &&
-            !isTargetWatchOS());
-  }
-
-  void addProfileRTLibs(const llvm::opt::ArgList &Args,
-                        llvm::opt::ArgStringList &CmdArgs) const override;
-
-protected:
-  /// }
-  /// @name Darwin specific Toolchain functions
-  /// {
-
-  // FIXME: Eliminate these ...Target functions and derive separate tool chains
-  // for these targets and put version in constructor.
-  void setTarget(DarwinPlatformKind Platform, unsigned Major, unsigned Minor,
-                 unsigned Micro) const {
-    // FIXME: For now, allow reinitialization as long as values don't
-    // change. This will go away when we move away from argument translation.
-    if (TargetInitialized && TargetPlatform == Platform &&
-        TargetVersion == VersionTuple(Major, Minor, Micro))
-      return;
-
-    assert(!TargetInitialized && "Target already initialized!");
-    TargetInitialized = true;
-    TargetPlatform = Platform;
-    TargetVersion = VersionTuple(Major, Minor, Micro);
-  }
-
-  bool isTargetIPhoneOS() const {
-    assert(TargetInitialized && "Target not initialized!");
-    return TargetPlatform == IPhoneOS || TargetPlatform == TvOS;
-  }
-
-  bool isTargetIOSSimulator() const {
-    assert(TargetInitialized && "Target not initialized!");
-    return TargetPlatform == IPhoneOSSimulator ||
-           TargetPlatform == TvOSSimulator;
-  }
-
-  bool isTargetIOSBased() const {
-    assert(TargetInitialized && "Target not initialized!");
-    return isTargetIPhoneOS() || isTargetIOSSimulator();
-  }
-
-  bool isTargetTvOS() const {
-    assert(TargetInitialized && "Target not initialized!");
-    return TargetPlatform == TvOS;
-  }
-
-  bool isTargetTvOSSimulator() const {
-    assert(TargetInitialized && "Target not initialized!");
-    return TargetPlatform == TvOSSimulator;
-  }
-
-  bool isTargetTvOSBased() const {
-    assert(TargetInitialized && "Target not initialized!");
-    return TargetPlatform == TvOS || TargetPlatform == TvOSSimulator;
-  }
-
-  bool isTargetWatchOS() const {
-    assert(TargetInitialized && "Target not initialized!");
-    return TargetPlatform == WatchOS;
-  }
-
-  bool isTargetWatchOSSimulator() const {
-    assert(TargetInitialized && "Target not initialized!");
-    return TargetPlatform == WatchOSSimulator;
-  }
-
-  bool isTargetWatchOSBased() const {
-    assert(TargetInitialized && "Target not initialized!");
-    return TargetPlatform == WatchOS || TargetPlatform == WatchOSSimulator;
-  }
-
-  bool isTargetMacOS() const {
-    assert(TargetInitialized && "Target not initialized!");
-    return TargetPlatform == MacOS;
-  }
-
-  bool isTargetInitialized() const { return TargetInitialized; }
-
-  VersionTuple getTargetVersion() const {
-    assert(TargetInitialized && "Target not initialized!");
-    return TargetVersion;
-  }
-
-  bool isIPhoneOSVersionLT(unsigned V0, unsigned V1 = 0,
-                           unsigned V2 = 0) const {
-    assert(isTargetIOSBased() && "Unexpected call for non iOS target!");
-    return TargetVersion < VersionTuple(V0, V1, V2);
-  }
-
-  bool isMacosxVersionLT(unsigned V0, unsigned V1 = 0, unsigned V2 = 0) const {
-    assert(isTargetMacOS() && "Unexpected call for non OS X target!");
-    return TargetVersion < VersionTuple(V0, V1, V2);
-  }
-
-  StringRef getPlatformFamily() const;
-  static StringRef getSDKName(StringRef isysroot);
-  StringRef getOSLibraryNameSuffix() const;
-
-public:
-  /// }
-  /// @name ToolChain Implementation
-  /// {
-
-  // Darwin tools support multiple architecture (e.g., i386 and x86_64) and
-  // most development is done against SDKs, so compiling for a different
-  // architecture should not get any special treatment.
-  bool isCrossCompiling() const override { return false; }
-
-  llvm::opt::DerivedArgList *
-  TranslateArgs(const llvm::opt::DerivedArgList &Args, StringRef BoundArch,
-                Action::OffloadKind DeviceOffloadKind) const override;
-
-  CXXStdlibType GetDefaultCXXStdlibType() const override;
-  ObjCRuntime getDefaultObjCRuntime(bool isNonFragile) const override;
-  bool hasBlocksRuntime() const override;
-
-  void AddCudaIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                          llvm::opt::ArgStringList &CC1Args) const override;
-
-  bool UseObjCMixedDispatch() const override {
-    // This is only used with the non-fragile ABI and non-legacy dispatch.
-
-    // Mixed dispatch is used everywhere except OS X before 10.6.
-    return !(isTargetMacOS() && isMacosxVersionLT(10, 6));
-  }
-
-  unsigned GetDefaultStackProtectorLevel(bool KernelOrKext) const override {
-    // Stack protectors default to on for user code on 10.5,
-    // and for everything in 10.6 and beyond
-    if (isTargetIOSBased() || isTargetWatchOSBased())
-      return 1;
-    else if (isTargetMacOS() && !isMacosxVersionLT(10, 6))
-      return 1;
-    else if (isTargetMacOS() && !isMacosxVersionLT(10, 5) && !KernelOrKext)
-      return 1;
-
-    return 0;
-  }
-
-  bool SupportsObjCGC() const override;
-
-  void CheckObjCARC() const override;
-
-  bool UseSjLjExceptions(const llvm::opt::ArgList &Args) const override;
-
-  bool SupportsEmbeddedBitcode() const override;
-
-  SanitizerMask getSupportedSanitizers() const override;
-
-  void printVerboseInfo(raw_ostream &OS) const override;
-};
-
-/// DarwinClang - The Darwin toolchain used by Clang.
-class LLVM_LIBRARY_VISIBILITY DarwinClang : public Darwin {
-public:
-  DarwinClang(const Driver &D, const llvm::Triple &Triple,
-              const llvm::opt::ArgList &Args);
-
-  /// @name Apple ToolChain Implementation
-  /// {
-
-  RuntimeLibType GetRuntimeLibType(const llvm::opt::ArgList &Args) const override;
-
-  void AddLinkRuntimeLibArgs(const llvm::opt::ArgList &Args,
-                             llvm::opt::ArgStringList &CmdArgs) const override;
-
-  void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
-                           llvm::opt::ArgStringList &CmdArgs) const override;
-
-  void AddCCKextLibArgs(const llvm::opt::ArgList &Args,
-                        llvm::opt::ArgStringList &CmdArgs) const override;
-
-  void addClangWarningOptions(llvm::opt::ArgStringList &CC1Args) const override;
-
-  void AddLinkARCArgs(const llvm::opt::ArgList &Args,
-                      llvm::opt::ArgStringList &CmdArgs) const override;
-
-  unsigned GetDefaultDwarfVersion() const override;
-  // Until dtrace (via CTF) and LLDB can deal with distributed debug info,
-  // Darwin defaults to standalone/full debug info.
-  bool GetDefaultStandaloneDebug() const override { return true; }
-  llvm::DebuggerKind getDefaultDebuggerTuning() const override {
-    return llvm::DebuggerKind::LLDB;
-  }
-
-  /// }
-
-private:
-  void AddLinkSanitizerLibArgs(const llvm::opt::ArgList &Args,
-                               llvm::opt::ArgStringList &CmdArgs,
-                               StringRef Sanitizer) const;
-};
-
-class LLVM_LIBRARY_VISIBILITY Generic_ELF : public Generic_GCC {
-  virtual void anchor();
-
-public:
-  Generic_ELF(const Driver &D, const llvm::Triple &Triple,
-              const llvm::opt::ArgList &Args)
-      : Generic_GCC(D, Triple, Args) {}
-
-  void addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
-                             llvm::opt::ArgStringList &CC1Args) const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY CloudABI : public Generic_ELF {
-public:
-  CloudABI(const Driver &D, const llvm::Triple &Triple,
-           const llvm::opt::ArgList &Args);
-  bool HasNativeLLVMSupport() const override { return true; }
-
-  bool IsMathErrnoDefault() const override { return false; }
-  bool IsObjCNonFragileABIDefault() const override { return true; }
-
-  CXXStdlibType
-  GetCXXStdlibType(const llvm::opt::ArgList &Args) const override {
-    return ToolChain::CST_Libcxx;
-  }
-  std::string findLibCxxIncludePath() const override;
-  void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
-                           llvm::opt::ArgStringList &CmdArgs) const override;
-
-  bool isPIEDefault() const override;
-  SanitizerMask getSupportedSanitizers() const override;
-  SanitizerMask getDefaultSanitizers() const override;
-
-protected:
-  Tool *buildLinker() const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY Solaris : public Generic_GCC {
-public:
-  Solaris(const Driver &D, const llvm::Triple &Triple,
-          const llvm::opt::ArgList &Args);
-
-  bool IsIntegratedAssemblerDefault() const override { return true; }
-
-  void AddClangCXXStdlibIncludeArgs(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-
-  unsigned GetDefaultDwarfVersion() const override { return 2; }
-
-protected:
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY MinGW : public ToolChain {
-public:
-  MinGW(const Driver &D, const llvm::Triple &Triple,
-        const llvm::opt::ArgList &Args);
-
-  bool IsIntegratedAssemblerDefault() const override;
-  bool IsUnwindTablesDefault() const override;
-  bool isPICDefault() const override;
-  bool isPIEDefault() const override;
-  bool isPICDefaultForced() const override;
-  bool UseSEHExceptions() const;
-
-  void
-  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                            llvm::opt::ArgStringList &CC1Args) const override;
-  void AddClangCXXStdlibIncludeArgs(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-
-  void AddCudaIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                          llvm::opt::ArgStringList &CC1Args) const override;
-
-  void printVerboseInfo(raw_ostream &OS) const override;
-
-protected:
-  Tool *getTool(Action::ActionClass AC) const override;
-  Tool *buildLinker() const override;
-  Tool *buildAssembler() const override;
-
-private:
-  CudaInstallationDetector CudaInstallation;
-
-  std::string Base;
-  std::string GccLibDir;
-  std::string Ver;
-  std::string Arch;
-  mutable std::unique_ptr<tools::gcc::Preprocessor> Preprocessor;
-  mutable std::unique_ptr<tools::gcc::Compiler> Compiler;
-  void findGccLibDir();
-};
-
-class LLVM_LIBRARY_VISIBILITY Haiku : public Generic_ELF {
-public:
-  Haiku(const Driver &D, const llvm::Triple &Triple,
-          const llvm::opt::ArgList &Args);
-
-  bool isPIEDefault() const override {
-    return getTriple().getArch() == llvm::Triple::x86_64;
-  }
-
-  std::string findLibCxxIncludePath() const override;
-  void addLibStdCxxIncludePaths(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY OpenBSD : public Generic_ELF {
-public:
-  OpenBSD(const Driver &D, const llvm::Triple &Triple,
-          const llvm::opt::ArgList &Args);
-
-  bool IsMathErrnoDefault() const override { return false; }
-  bool IsObjCNonFragileABIDefault() const override { return true; }
-  bool isPIEDefault() const override { return true; }
-
-  unsigned GetDefaultStackProtectorLevel(bool KernelOrKext) const override {
-    return 2;
-  }
-  unsigned GetDefaultDwarfVersion() const override { return 2; }
-
-protected:
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY Bitrig : public Generic_ELF {
-public:
-  Bitrig(const Driver &D, const llvm::Triple &Triple,
-         const llvm::opt::ArgList &Args);
-
-  bool IsMathErrnoDefault() const override { return false; }
-  bool IsObjCNonFragileABIDefault() const override { return true; }
-
-  CXXStdlibType GetDefaultCXXStdlibType() const override;
-  void addLibStdCxxIncludePaths(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-  void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
-                           llvm::opt::ArgStringList &CmdArgs) const override;
-  unsigned GetDefaultStackProtectorLevel(bool KernelOrKext) const override {
-    return 1;
-  }
-
-protected:
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY FreeBSD : public Generic_ELF {
-public:
-  FreeBSD(const Driver &D, const llvm::Triple &Triple,
-          const llvm::opt::ArgList &Args);
-  bool HasNativeLLVMSupport() const override;
-
-  bool IsMathErrnoDefault() const override { return false; }
-  bool IsObjCNonFragileABIDefault() const override { return true; }
-
-  CXXStdlibType GetDefaultCXXStdlibType() const override;
-  void addLibStdCxxIncludePaths(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-  void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
-                           llvm::opt::ArgStringList &CmdArgs) const override;
-
-  bool UseSjLjExceptions(const llvm::opt::ArgList &Args) const override;
-  bool isPIEDefault() const override;
-  SanitizerMask getSupportedSanitizers() const override;
-  unsigned GetDefaultDwarfVersion() const override { return 2; }
-  // Until dtrace (via CTF) and LLDB can deal with distributed debug info,
-  // FreeBSD defaults to standalone/full debug info.
-  bool GetDefaultStandaloneDebug() const override { return true; }
-
-protected:
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY NetBSD : public Generic_ELF {
-public:
-  NetBSD(const Driver &D, const llvm::Triple &Triple,
-         const llvm::opt::ArgList &Args);
-
-  bool IsMathErrnoDefault() const override { return false; }
-  bool IsObjCNonFragileABIDefault() const override { return true; }
-
-  CXXStdlibType GetDefaultCXXStdlibType() const override;
-
-  std::string findLibCxxIncludePath() const override;
-  void addLibStdCxxIncludePaths(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-
-  bool IsUnwindTablesDefault() const override { return true; }
-
-protected:
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY Minix : public Generic_ELF {
-public:
-  Minix(const Driver &D, const llvm::Triple &Triple,
-        const llvm::opt::ArgList &Args);
-
-protected:
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY DragonFly : public Generic_ELF {
-public:
-  DragonFly(const Driver &D, const llvm::Triple &Triple,
-            const llvm::opt::ArgList &Args);
-
-  bool IsMathErrnoDefault() const override { return false; }
-
-protected:
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY Linux : public Generic_ELF {
-public:
-  Linux(const Driver &D, const llvm::Triple &Triple,
-        const llvm::opt::ArgList &Args);
-
-  bool HasNativeLLVMSupport() const override;
-
-  void
-  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                            llvm::opt::ArgStringList &CC1Args) const override;
-  std::string findLibCxxIncludePath() const override;
-  void addLibStdCxxIncludePaths(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-  void AddCudaIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                          llvm::opt::ArgStringList &CC1Args) const override;
-  void AddIAMCUIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                           llvm::opt::ArgStringList &CC1Args) const override;
-  bool isPIEDefault() const override;
-  SanitizerMask getSupportedSanitizers() const override;
-  void addProfileRTLibs(const llvm::opt::ArgList &Args,
-                        llvm::opt::ArgStringList &CmdArgs) const override;
-  virtual std::string computeSysRoot() const;
-
-  virtual std::string getDynamicLinker(const llvm::opt::ArgList &Args) const;
-
-  std::vector<std::string> ExtraOpts;
-
-protected:
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY CudaToolChain : public ToolChain {
-public:
-  CudaToolChain(const Driver &D, const llvm::Triple &Triple,
-                const ToolChain &HostTC, const llvm::opt::ArgList &Args);
-
-  virtual const llvm::Triple *getAuxTriple() const override {
-    return &HostTC.getTriple();
-  }
-
-  llvm::opt::DerivedArgList *
-  TranslateArgs(const llvm::opt::DerivedArgList &Args, StringRef BoundArch,
-                Action::OffloadKind DeviceOffloadKind) const override;
-  void addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
-                             llvm::opt::ArgStringList &CC1Args) const override;
-
-  // Never try to use the integrated assembler with CUDA; always fork out to
-  // ptxas.
-  bool useIntegratedAs() const override { return false; }
-  bool isCrossCompiling() const override { return true; }
-  bool isPICDefault() const override { return false; }
-  bool isPIEDefault() const override { return false; }
-  bool isPICDefaultForced() const override { return false; }
-  bool SupportsProfiling() const override { return false; }
-  bool SupportsObjCGC() const override { return false; }
-
-  void AddCudaIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                          llvm::opt::ArgStringList &CC1Args) const override;
-
-  void addClangWarningOptions(llvm::opt::ArgStringList &CC1Args) const override;
-  CXXStdlibType GetCXXStdlibType(const llvm::opt::ArgList &Args) const override;
-  void
-  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                            llvm::opt::ArgStringList &CC1Args) const override;
-  void AddClangCXXStdlibIncludeArgs(
-      const llvm::opt::ArgList &Args,
-      llvm::opt::ArgStringList &CC1Args) const override;
-  void AddIAMCUIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                           llvm::opt::ArgStringList &CC1Args) const override;
-
-  SanitizerMask getSupportedSanitizers() const override;
-
-  VersionTuple
-  computeMSVCVersion(const Driver *D,
-                     const llvm::opt::ArgList &Args) const override;
-
-  const ToolChain &HostTC;
-  CudaInstallationDetector CudaInstallation;
-
-protected:
-  Tool *buildAssembler() const override;  // ptxas
-  Tool *buildLinker() const override;     // fatbinary (ok, not really a linker)
-};
-
-class LLVM_LIBRARY_VISIBILITY MipsLLVMToolChain : public Linux {
-protected:
-  Tool *buildLinker() const override;
-
-public:
-  MipsLLVMToolChain(const Driver &D, const llvm::Triple &Triple,
-                    const llvm::opt::ArgList &Args);
-
-  void
-  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                            llvm::opt::ArgStringList &CC1Args) const override;
-
-  CXXStdlibType GetCXXStdlibType(const llvm::opt::ArgList &Args) const override;
-
-  std::string findLibCxxIncludePath() const override;
-
-  void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
-                           llvm::opt::ArgStringList &CmdArgs) const override;
-
-  std::string getCompilerRT(const llvm::opt::ArgList &Args, StringRef Component,
-                            bool Shared = false) const override;
-
-  std::string computeSysRoot() const override;
-
-  RuntimeLibType GetDefaultRuntimeLibType() const override {
-    return GCCInstallation.isValid() ? RuntimeLibType::RLT_Libgcc
-                                     : RuntimeLibType::RLT_CompilerRT;
-  }
-
-  const char *getDefaultLinker() const override {
-    return "lld";
-  }
-
-private:
-  Multilib SelectedMultilib;
-  std::string LibSuffix;
-};
-
-class LLVM_LIBRARY_VISIBILITY LanaiToolChain : public Generic_ELF {
-public:
-  LanaiToolChain(const Driver &D, const llvm::Triple &Triple,
-                 const llvm::opt::ArgList &Args)
-      : Generic_ELF(D, Triple, Args) {}
-
-  // No support for finding a C++ standard library yet.
-  std::string findLibCxxIncludePath() const override { return ""; }
-  void addLibStdCxxIncludePaths(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override {}
-
-  bool IsIntegratedAssemblerDefault() const override { return true; }
-};
-
-class LLVM_LIBRARY_VISIBILITY HexagonToolChain : public Linux {
-protected:
-  GCCVersion GCCLibAndIncVersion;
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-
-public:
-  HexagonToolChain(const Driver &D, const llvm::Triple &Triple,
-                   const llvm::opt::ArgList &Args);
-  ~HexagonToolChain() override;
-
-  void
-  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                            llvm::opt::ArgStringList &CC1Args) const override;
-  void addLibStdCxxIncludePaths(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-  CXXStdlibType GetCXXStdlibType(const llvm::opt::ArgList &Args) const override;
-
-  StringRef GetGCCLibAndIncVersion() const { return GCCLibAndIncVersion.Text; }
-  bool IsIntegratedAssemblerDefault() const override {
-    return true;
-  }
-
-  std::string getHexagonTargetDir(
-      const std::string &InstalledDir,
-      const SmallVectorImpl<std::string> &PrefixDirs) const;
-  void getHexagonLibraryPaths(const llvm::opt::ArgList &Args,
-      ToolChain::path_list &LibPaths) const;
-
-  static const StringRef GetDefaultCPU();
-  static const StringRef GetTargetCPUVersion(const llvm::opt::ArgList &Args);
-
-  static Optional<unsigned> getSmallDataThreshold(
-      const llvm::opt::ArgList &Args);
-};
-
-class LLVM_LIBRARY_VISIBILITY AMDGPUToolChain : public Generic_ELF {
-protected:
-  Tool *buildLinker() const override;
-
-public:
-  AMDGPUToolChain(const Driver &D, const llvm::Triple &Triple,
-            const llvm::opt::ArgList &Args);
-  unsigned GetDefaultDwarfVersion() const override { return 2; }
-  bool IsIntegratedAssemblerDefault() const override { return true; }
-};
-
-class LLVM_LIBRARY_VISIBILITY NaClToolChain : public Generic_ELF {
-public:
-  NaClToolChain(const Driver &D, const llvm::Triple &Triple,
-                const llvm::opt::ArgList &Args);
-
-  void
-  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                            llvm::opt::ArgStringList &CC1Args) const override;
-  std::string findLibCxxIncludePath() const override;
-
-  CXXStdlibType GetCXXStdlibType(const llvm::opt::ArgList &Args) const override;
-
-  void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
-                           llvm::opt::ArgStringList &CmdArgs) const override;
-
-  bool IsIntegratedAssemblerDefault() const override {
-    return getTriple().getArch() == llvm::Triple::mipsel;
-  }
-
-  // Get the path to the file containing NaCl's ARM macros.
-  // It lives in NaClToolChain because the ARMAssembler tool needs a
-  // const char * that it can pass around,
-  const char *GetNaClArmMacrosPath() const { return NaClArmMacrosPath.c_str(); }
-
-  std::string ComputeEffectiveClangTriple(const llvm::opt::ArgList &Args,
-                                          types::ID InputType) const override;
-
-protected:
-  Tool *buildLinker() const override;
-  Tool *buildAssembler() const override;
-
-private:
-  std::string NaClArmMacrosPath;
-};
-
-class LLVM_LIBRARY_VISIBILITY Fuchsia : public Generic_ELF {
-public:
-  Fuchsia(const Driver &D, const llvm::Triple &Triple,
-          const llvm::opt::ArgList &Args);
-
-  bool isPIEDefault() const override { return true; }
-  bool HasNativeLLVMSupport() const override { return true; }
-  bool IsIntegratedAssemblerDefault() const override { return true; }
-  llvm::DebuggerKind getDefaultDebuggerTuning() const override {
-    return llvm::DebuggerKind::GDB;
-  }
-
-  RuntimeLibType
-  GetRuntimeLibType(const llvm::opt::ArgList &Args) const override;
-  CXXStdlibType
-  GetCXXStdlibType(const llvm::opt::ArgList &Args) const override;
-
-  void addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
-                             llvm::opt::ArgStringList &CC1Args) const override;
-  void
-  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                            llvm::opt::ArgStringList &CC1Args) const override;
-  std::string findLibCxxIncludePath() const override;
-  void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
-                           llvm::opt::ArgStringList &CmdArgs) const override;
-
-  const char *getDefaultLinker() const override {
-    return "lld";
-  }
-
-protected:
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-};
-
-/// TCEToolChain - A tool chain using the llvm bitcode tools to perform
-/// all subcommands. See http://tce.cs.tut.fi for our peculiar target.
-class LLVM_LIBRARY_VISIBILITY TCEToolChain : public ToolChain {
-public:
-  TCEToolChain(const Driver &D, const llvm::Triple &Triple,
-               const llvm::opt::ArgList &Args);
-  ~TCEToolChain() override;
-
-  bool IsMathErrnoDefault() const override;
-  bool isPICDefault() const override;
-  bool isPIEDefault() const override;
-  bool isPICDefaultForced() const override;
-};
-
-/// Toolchain for little endian TCE cores.
-class LLVM_LIBRARY_VISIBILITY TCELEToolChain : public TCEToolChain {
-public:
-  TCELEToolChain(const Driver &D, const llvm::Triple &Triple,
-                 const llvm::opt::ArgList &Args);
-  ~TCELEToolChain() override;
-};
-
-class LLVM_LIBRARY_VISIBILITY MSVCToolChain : public ToolChain {
-public:
-  MSVCToolChain(const Driver &D, const llvm::Triple &Triple,
-                const llvm::opt::ArgList &Args);
-
-  llvm::opt::DerivedArgList *
-  TranslateArgs(const llvm::opt::DerivedArgList &Args, StringRef BoundArch,
-                Action::OffloadKind DeviceOffloadKind) const override;
-
-  bool IsIntegratedAssemblerDefault() const override;
-  bool IsUnwindTablesDefault() const override;
-  bool isPICDefault() const override;
-  bool isPIEDefault() const override;
-  bool isPICDefaultForced() const override;
-
-  void
-  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                            llvm::opt::ArgStringList &CC1Args) const override;
-  void AddClangCXXStdlibIncludeArgs(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-
-  void AddCudaIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                          llvm::opt::ArgStringList &CC1Args) const override;
-
-  bool getWindowsSDKDir(std::string &path, int &major,
-                        std::string &windowsSDKIncludeVersion,
-                        std::string &windowsSDKLibVersion) const;
-  bool getWindowsSDKLibraryPath(std::string &path) const;
-  /// \brief Check if Universal CRT should be used if available
-  bool useUniversalCRT(std::string &visualStudioDir) const;
-  bool getUniversalCRTSdkDir(std::string &path, std::string &ucrtVersion) const;
-  bool getUniversalCRTLibraryPath(std::string &path) const;
-  bool getVisualStudioInstallDir(std::string &path) const;
-  bool getVisualStudioBinariesFolder(const char *clangProgramPath,
-                                     std::string &path) const;
-  VersionTuple
-  computeMSVCVersion(const Driver *D,
-                     const llvm::opt::ArgList &Args) const override;
-
-  std::string ComputeEffectiveClangTriple(const llvm::opt::ArgList &Args,
-                                          types::ID InputType) const override;
-  SanitizerMask getSupportedSanitizers() const override;
-
-  void printVerboseInfo(raw_ostream &OS) const override;
-
-protected:
-  void AddSystemIncludeWithSubfolder(const llvm::opt::ArgList &DriverArgs,
-                                     llvm::opt::ArgStringList &CC1Args,
-                                     const std::string &folder,
-                                     const Twine &subfolder1,
-                                     const Twine &subfolder2 = "",
-                                     const Twine &subfolder3 = "") const;
-
-  Tool *buildLinker() const override;
-  Tool *buildAssembler() const override;
-private:
-  VersionTuple getMSVCVersionFromTriple() const;
-  VersionTuple getMSVCVersionFromExe() const;
-
-  CudaInstallationDetector CudaInstallation;
-};
-
-class LLVM_LIBRARY_VISIBILITY CrossWindowsToolChain : public Generic_GCC {
-public:
-  CrossWindowsToolChain(const Driver &D, const llvm::Triple &T,
-                        const llvm::opt::ArgList &Args);
-
-  bool IsIntegratedAssemblerDefault() const override { return true; }
-  bool IsUnwindTablesDefault() const override;
-  bool isPICDefault() const override;
-  bool isPIEDefault() const override;
-  bool isPICDefaultForced() const override;
-
-  unsigned int GetDefaultStackProtectorLevel(bool KernelOrKext) const override {
-    return 0;
-  }
-
-  void
-  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                            llvm::opt::ArgStringList &CC1Args) const override;
-  void AddClangCXXStdlibIncludeArgs(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-  void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
-                           llvm::opt::ArgStringList &CmdArgs) const override;
-
-  SanitizerMask getSupportedSanitizers() const override;
-
-protected:
-  Tool *buildLinker() const override;
-  Tool *buildAssembler() const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY XCoreToolChain : public ToolChain {
-public:
-  XCoreToolChain(const Driver &D, const llvm::Triple &Triple,
-                 const llvm::opt::ArgList &Args);
-
-protected:
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-
-public:
-  bool isPICDefault() const override;
-  bool isPIEDefault() const override;
-  bool isPICDefaultForced() const override;
-  bool SupportsProfiling() const override;
-  bool hasBlocksRuntime() const override;
-  void
-  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                            llvm::opt::ArgStringList &CC1Args) const override;
-  void addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
-                             llvm::opt::ArgStringList &CC1Args) const override;
-  void AddClangCXXStdlibIncludeArgs(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-  void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
-                           llvm::opt::ArgStringList &CmdArgs) const override;
-};
-
-/// MyriadToolChain - A tool chain using either clang or the external compiler
-/// installed by the Movidius SDK to perform all subcommands.
-class LLVM_LIBRARY_VISIBILITY MyriadToolChain : public Generic_ELF {
-public:
-  MyriadToolChain(const Driver &D, const llvm::Triple &Triple,
-                  const llvm::opt::ArgList &Args);
-  ~MyriadToolChain() override;
-
-  void
-  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
-                            llvm::opt::ArgStringList &CC1Args) const override;
-  std::string findLibCxxIncludePath() const override;
-  void addLibStdCxxIncludePaths(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-  Tool *SelectTool(const JobAction &JA) const override;
-  unsigned GetDefaultDwarfVersion() const override { return 2; }
-  SanitizerMask getSupportedSanitizers() const override;
-
-protected:
-  Tool *buildLinker() const override;
-  bool isShaveCompilation(const llvm::Triple &T) const {
-    return T.getArch() == llvm::Triple::shave;
-  }
-
-private:
-  mutable std::unique_ptr<Tool> Compiler;
-  mutable std::unique_ptr<Tool> Assembler;
-};
-
-class LLVM_LIBRARY_VISIBILITY WebAssembly final : public ToolChain {
-public:
-  WebAssembly(const Driver &D, const llvm::Triple &Triple,
-              const llvm::opt::ArgList &Args);
-
-private:
-  bool IsMathErrnoDefault() const override;
-  bool IsObjCNonFragileABIDefault() const override;
-  bool UseObjCMixedDispatch() const override;
-  bool isPICDefault() const override;
-  bool isPIEDefault() const override;
-  bool isPICDefaultForced() const override;
-  bool IsIntegratedAssemblerDefault() const override;
-  bool hasBlocksRuntime() const override;
-  bool SupportsObjCGC() const override;
-  bool SupportsProfiling() const override;
-  bool HasNativeLLVMSupport() const override;
-  void addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
-                             llvm::opt::ArgStringList &CC1Args) const override;
-  RuntimeLibType GetDefaultRuntimeLibType() const override;
-  CXXStdlibType GetCXXStdlibType(const llvm::opt::ArgList &Args) const override;
-  void AddClangSystemIncludeArgs(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-  void AddClangCXXStdlibIncludeArgs(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override;
-
-  const char *getDefaultLinker() const override {
-    return "lld";
-  }
-
-  Tool *buildLinker() const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY PS4CPU : public Generic_ELF {
-public:
-  PS4CPU(const Driver &D, const llvm::Triple &Triple,
-         const llvm::opt::ArgList &Args);
-
-  // No support for finding a C++ standard library yet.
-  std::string findLibCxxIncludePath() const override { return ""; }
-  void addLibStdCxxIncludePaths(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override {}
-
-  bool IsMathErrnoDefault() const override { return false; }
-  bool IsObjCNonFragileABIDefault() const override { return true; }
-  bool HasNativeLLVMSupport() const override;
-  bool isPICDefault() const override;
-
-  unsigned GetDefaultStackProtectorLevel(bool KernelOrKext) const override {
-    return 2; // SSPStrong
-  }
-
-  llvm::DebuggerKind getDefaultDebuggerTuning() const override {
-    return llvm::DebuggerKind::SCE;
-  }
-
-  SanitizerMask getSupportedSanitizers() const override;
-
-protected:
-  Tool *buildAssembler() const override;
-  Tool *buildLinker() const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY Contiki : public Generic_ELF {
-public:
-  Contiki(const Driver &D, const llvm::Triple &Triple,
-          const llvm::opt::ArgList &Args);
-
-  // No support for finding a C++ standard library yet.
-  std::string findLibCxxIncludePath() const override { return ""; }
-  void addLibStdCxxIncludePaths(
-      const llvm::opt::ArgList &DriverArgs,
-      llvm::opt::ArgStringList &CC1Args) const override {}
-
-  SanitizerMask getSupportedSanitizers() const override;
-};
-
-class LLVM_LIBRARY_VISIBILITY AVRToolChain : public Generic_ELF {
-protected:
-  Tool *buildLinker() const override;
-public:
-  AVRToolChain(const Driver &D, const llvm::Triple &Triple,
-               const llvm::opt::ArgList &Args);
-  bool IsIntegratedAssemblerDefault() const override { return true; }
-};
-
-
-} // end namespace toolchains
-} // end namespace driver
-} // end namespace clang
-
-#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_H
diff --git a/lib/Driver/ToolChains/AMDGPU.cpp b/lib/Driver/ToolChains/AMDGPU.cpp
new file mode 100644
index 000000000000..63e1749e0088
--- /dev/null
+++ b/lib/Driver/ToolChains/AMDGPU.cpp
@@ -0,0 +1,45 @@
+//===--- AMDGPU.cpp - AMDGPU ToolChain Implementations ----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "AMDGPU.h"
+#include "InputInfo.h"
+#include "CommonArgs.h"
+#include "clang/Driver/Compilation.h"
+#include "llvm/Option/ArgList.h"
+
+using namespace clang::driver;
+using namespace clang::driver::tools;
+using namespace clang::driver::toolchains;
+using namespace clang;
+using namespace llvm::opt;
+
+void amdgpu::Linker::ConstructJob(Compilation &C, const JobAction &JA,
+                                  const InputInfo &Output,
+                                  const InputInfoList &Inputs,
+                                  const ArgList &Args,
+                                  const char *LinkingOutput) const {
+
+  std::string Linker = getToolChain().GetProgramPath(getShortName());
+  ArgStringList CmdArgs;
+  AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs, JA);
+  CmdArgs.push_back("-shared");
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+  C.addCommand(llvm::make_unique<Command>(JA, *this, Args.MakeArgString(Linker),
+                                          CmdArgs, Inputs));
+}
+
+/// AMDGPU Toolchain
+AMDGPUToolChain::AMDGPUToolChain(const Driver &D, const llvm::Triple &Triple,
+                                 const ArgList &Args)
+  : Generic_ELF(D, Triple, Args) { }
+
+Tool *AMDGPUToolChain::buildLinker() const {
+  return new tools::amdgpu::Linker(*this);
+}
diff --git a/lib/Driver/ToolChains/AMDGPU.h b/lib/Driver/ToolChains/AMDGPU.h
new file mode 100644
index 000000000000..9af1e96489eb
--- /dev/null
+++ b/lib/Driver/ToolChains/AMDGPU.h
@@ -0,0 +1,54 @@
+//===--- AMDGPU.h - AMDGPU ToolChain Implementations ----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_AMDGPU_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_AMDGPU_H
+
+#include "Gnu.h"
+#include "clang/Driver/Tool.h"
+#include "clang/Driver/ToolChain.h"
+
+namespace clang {
+namespace driver {
+namespace tools {
+
+namespace amdgpu {
+
+class LLVM_LIBRARY_VISIBILITY Linker : public GnuTool {
+public:
+  Linker(const ToolChain &TC) : GnuTool("amdgpu::Linker", "ld.lld", TC) {}
+  bool isLinkJob() const override { return true; }
+  bool hasIntegratedCPP() const override { return false; }
+  void ConstructJob(Compilation &C, const JobAction &JA,
+                    const InputInfo &Output, const InputInfoList &Inputs,
+                    const llvm::opt::ArgList &TCArgs,
+                    const char *LinkingOutput) const override;
+};
+
+} // end namespace amdgpu
+} // end namespace tools
+
+namespace toolchains {
+
+class LLVM_LIBRARY_VISIBILITY AMDGPUToolChain : public Generic_ELF {
+protected:
+  Tool *buildLinker() const override;
+
+public:
+  AMDGPUToolChain(const Driver &D, const llvm::Triple &Triple,
+            const llvm::opt::ArgList &Args);
+  unsigned GetDefaultDwarfVersion() const override { return 2; }
+  bool IsIntegratedAssemblerDefault() const override { return true; }
+};
+
+} // end namespace toolchains
+} // end namespace driver
+} // end namespace clang
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_AMDGPU_H
diff --git a/lib/Driver/ToolChains/AVR.cpp b/lib/Driver/ToolChains/AVR.cpp
new file mode 100644
index 000000000000..877009af8a30
--- /dev/null
+++ b/lib/Driver/ToolChains/AVR.cpp
@@ -0,0 +1,44 @@
+//===--- AVR.cpp - AVR ToolChain Implementations ----------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "AVR.h"
+#include "CommonArgs.h"
+#include "InputInfo.h"
+#include "clang/Driver/Compilation.h"
+#include "llvm/Option/ArgList.h"
+
+using namespace clang::driver;
+using namespace clang::driver::toolchains;
+using namespace clang::driver::tools;
+using namespace clang;
+using namespace llvm::opt;
+
+/// AVR Toolchain
+AVRToolChain::AVRToolChain(const Driver &D, const llvm::Triple &Triple,
+                           const ArgList &Args)
+  : Generic_ELF(D, Triple, Args) { }
+Tool *AVRToolChain::buildLinker() const {
+  return new tools::AVR::Linker(*this);
+}
+
+void AVR::Linker::ConstructJob(Compilation &C, const JobAction &JA,
+                               const InputInfo &Output,
+                               const InputInfoList &Inputs,
+                               const ArgList &Args,
+                               const char *LinkingOutput) const {
+
+  std::string Linker = getToolChain().GetProgramPath(getShortName());
+  ArgStringList CmdArgs;
+  AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs, JA);
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+  C.addCommand(llvm::make_unique<Command>(JA, *this, Args.MakeArgString(Linker),
+                                          CmdArgs, Inputs));
+}
+// AVR tools end.
diff --git a/lib/Driver/ToolChains/AVR.h b/lib/Driver/ToolChains/AVR.h
new file mode 100644
index 000000000000..a7479a7f5652
--- /dev/null
+++ b/lib/Driver/ToolChains/AVR.h
@@ -0,0 +1,49 @@
+//===--- AVR.h - AVR Tool and ToolChain Implementations ---------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_AVR_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_AVR_H
+
+#include "Gnu.h"
+#include "InputInfo.h"
+#include "clang/Driver/ToolChain.h"
+#include "clang/Driver/Tool.h"
+
+namespace clang {
+namespace driver {
+namespace toolchains {
+
+class LLVM_LIBRARY_VISIBILITY AVRToolChain : public Generic_ELF {
+protected:
+  Tool *buildLinker() const override;
+public:
+  AVRToolChain(const Driver &D, const llvm::Triple &Triple,
+               const llvm::opt::ArgList &Args);
+};
+
+} // end namespace toolchains
+
+namespace tools {
+namespace AVR {
+class LLVM_LIBRARY_VISIBILITY Linker : public GnuTool {
+public:
+  Linker(const ToolChain &TC) : GnuTool("AVR::Linker", "avr-ld", TC) {}
+  bool hasIntegratedCPP() const override { return false; }
+  bool isLinkJob() const override { return true; }
+  void ConstructJob(Compilation &C, const JobAction &JA,
+                    const InputInfo &Output, const InputInfoList &Inputs,
+                    const llvm::opt::ArgList &TCArgs,
+                    const char *LinkingOutput) const override;
+};
+} // end namespace AVR
+} // end namespace tools
+} // end namespace driver
+} // end namespace clang
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_AVR_H
diff --git a/lib/Driver/ToolChains/Arch/AArch64.cpp b/lib/Driver/ToolChains/Arch/AArch64.cpp
new file mode 100644
index 000000000000..554d051fb155
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/AArch64.cpp
@@ -0,0 +1,199 @@
+//===--- AArch64.cpp - AArch64 (not ARM) Helpers for Tools ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "AArch64.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Options.h"
+#include "llvm/Option/ArgList.h"
+#include "llvm/Support/TargetParser.h"
+
+using namespace clang::driver;
+using namespace clang::driver::tools;
+using namespace clang;
+using namespace llvm::opt;
+
+/// getAArch64TargetCPU - Get the (LLVM) name of the AArch64 cpu we are
+/// targeting. Set \p A to the Arg corresponding to the -mcpu or -mtune
+/// arguments if they are provided, or to nullptr otherwise.
+std::string aarch64::getAArch64TargetCPU(const ArgList &Args, Arg *&A) {
+  std::string CPU;
+  // If we have -mtune or -mcpu, use that.
+  if ((A = Args.getLastArg(clang::driver::options::OPT_mtune_EQ))) {
+    CPU = StringRef(A->getValue()).lower();
+  } else if ((A = Args.getLastArg(options::OPT_mcpu_EQ))) {
+    StringRef Mcpu = A->getValue();
+    CPU = Mcpu.split("+").first.lower();
+  }
+
+  // Handle CPU name is 'native'.
+  if (CPU == "native")
+    return llvm::sys::getHostCPUName();
+  else if (CPU.size())
+    return CPU;
+
+  // Make sure we pick "cyclone" if -arch is used.
+  // FIXME: Should this be picked by checking the target triple instead?
+  if (Args.getLastArg(options::OPT_arch))
+    return "cyclone";
+
+  return "generic";
+}
+
+// Decode AArch64 features from string like +[no]featureA+[no]featureB+...
+static bool DecodeAArch64Features(const Driver &D, StringRef text,
+                                  std::vector<StringRef> &Features) {
+  SmallVector<StringRef, 8> Split;
+  text.split(Split, StringRef("+"), -1, false);
+
+  for (StringRef Feature : Split) {
+    StringRef FeatureName = llvm::AArch64::getArchExtFeature(Feature);
+    if (!FeatureName.empty())
+      Features.push_back(FeatureName);
+    else if (Feature == "neon" || Feature == "noneon")
+      D.Diag(clang::diag::err_drv_no_neon_modifier);
+    else
+      return false;
+  }
+  return true;
+}
+
+// Check if the CPU name and feature modifiers in -mcpu are legal. If yes,
+// decode CPU and feature.
+static bool DecodeAArch64Mcpu(const Driver &D, StringRef Mcpu, StringRef &CPU,
+                              std::vector<StringRef> &Features) {
+  std::pair<StringRef, StringRef> Split = Mcpu.split("+");
+  CPU = Split.first;
+
+  if (CPU == "generic") {
+    Features.push_back("+neon");
+  } else {
+    unsigned ArchKind = llvm::AArch64::parseCPUArch(CPU);
+    if (!llvm::AArch64::getArchFeatures(ArchKind, Features))
+      return false;
+
+    unsigned Extension = llvm::AArch64::getDefaultExtensions(CPU, ArchKind);
+    if (!llvm::AArch64::getExtensionFeatures(Extension, Features))
+      return false;
+   }
+
+  if (Split.second.size() && !DecodeAArch64Features(D, Split.second, Features))
+    return false;
+
+  return true;
+}
+
+static bool
+getAArch64ArchFeaturesFromMarch(const Driver &D, StringRef March,
+                                const ArgList &Args,
+                                std::vector<StringRef> &Features) {
+  std::string MarchLowerCase = March.lower();
+  std::pair<StringRef, StringRef> Split = StringRef(MarchLowerCase).split("+");
+
+  unsigned ArchKind = llvm::AArch64::parseArch(Split.first);
+  if (ArchKind == static_cast<unsigned>(llvm::AArch64::ArchKind::AK_INVALID) ||
+      !llvm::AArch64::getArchFeatures(ArchKind, Features) ||
+      (Split.second.size() && !DecodeAArch64Features(D, Split.second, Features)))
+    return false;
+
+  return true;
+}
+
+static bool
+getAArch64ArchFeaturesFromMcpu(const Driver &D, StringRef Mcpu,
+                               const ArgList &Args,
+                               std::vector<StringRef> &Features) {
+  StringRef CPU;
+  std::string McpuLowerCase = Mcpu.lower();
+  if (!DecodeAArch64Mcpu(D, McpuLowerCase, CPU, Features))
+    return false;
+
+  return true;
+}
+
+static bool
+getAArch64MicroArchFeaturesFromMtune(const Driver &D, StringRef Mtune,
+                                     const ArgList &Args,
+                                     std::vector<StringRef> &Features) {
+  std::string MtuneLowerCase = Mtune.lower();
+  // Handle CPU name is 'native'.
+  if (MtuneLowerCase == "native")
+    MtuneLowerCase = llvm::sys::getHostCPUName();
+  if (MtuneLowerCase == "cyclone") {
+    Features.push_back("+zcm");
+    Features.push_back("+zcz");
+  }
+  return true;
+}
+
+static bool
+getAArch64MicroArchFeaturesFromMcpu(const Driver &D, StringRef Mcpu,
+                                    const ArgList &Args,
+                                    std::vector<StringRef> &Features) {
+  StringRef CPU;
+  std::vector<StringRef> DecodedFeature;
+  std::string McpuLowerCase = Mcpu.lower();
+  if (!DecodeAArch64Mcpu(D, McpuLowerCase, CPU, DecodedFeature))
+    return false;
+
+  return getAArch64MicroArchFeaturesFromMtune(D, CPU, Args, Features);
+}
+
+void aarch64::getAArch64TargetFeatures(const Driver &D, const ArgList &Args,
+                                       std::vector<StringRef> &Features) {
+  Arg *A;
+  bool success = true;
+  // Enable NEON by default.
+  Features.push_back("+neon");
+  if ((A = Args.getLastArg(options::OPT_march_EQ)))
+    success = getAArch64ArchFeaturesFromMarch(D, A->getValue(), Args, Features);
+  else if ((A = Args.getLastArg(options::OPT_mcpu_EQ)))
+    success = getAArch64ArchFeaturesFromMcpu(D, A->getValue(), Args, Features);
+  else if (Args.hasArg(options::OPT_arch))
+    success = getAArch64ArchFeaturesFromMcpu(D, getAArch64TargetCPU(Args, A),
+                                             Args, Features);
+
+  if (success && (A = Args.getLastArg(clang::driver::options::OPT_mtune_EQ)))
+    success =
+        getAArch64MicroArchFeaturesFromMtune(D, A->getValue(), Args, Features);
+  else if (success && (A = Args.getLastArg(options::OPT_mcpu_EQ)))
+    success =
+        getAArch64MicroArchFeaturesFromMcpu(D, A->getValue(), Args, Features);
+  else if (success && Args.hasArg(options::OPT_arch))
+    success = getAArch64MicroArchFeaturesFromMcpu(
+        D, getAArch64TargetCPU(Args, A), Args, Features);
+
+  if (!success)
+    D.Diag(diag::err_drv_clang_unsupported) << A->getAsString(Args);
+
+  if (Args.getLastArg(options::OPT_mgeneral_regs_only)) {
+    Features.push_back("-fp-armv8");
+    Features.push_back("-crypto");
+    Features.push_back("-neon");
+  }
+
+  // En/disable crc
+  if (Arg *A = Args.getLastArg(options::OPT_mcrc, options::OPT_mnocrc)) {
+    if (A->getOption().matches(options::OPT_mcrc))
+      Features.push_back("+crc");
+    else
+      Features.push_back("-crc");
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_mno_unaligned_access,
+                               options::OPT_munaligned_access))
+    if (A->getOption().matches(options::OPT_mno_unaligned_access))
+      Features.push_back("+strict-align");
+
+  if (Args.hasArg(options::OPT_ffixed_x18))
+    Features.push_back("+reserve-x18");
+
+  if (Args.hasArg(options::OPT_mno_neg_immediates))
+    Features.push_back("+no-neg-immediates");
+}
diff --git a/lib/Driver/ToolChains/Arch/AArch64.h b/lib/Driver/ToolChains/Arch/AArch64.h
new file mode 100644
index 000000000000..62e419cc19f7
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/AArch64.h
@@ -0,0 +1,35 @@
+//===--- AArch64.h - AArch64-specific (not ARM) Tool Helpers ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_AARCH64_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_AARCH64_H
+
+#include "clang/Driver/Driver.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Option/Option.h"
+#include <string>
+#include <vector>
+
+namespace clang {
+namespace driver {
+namespace tools {
+namespace aarch64 {
+
+void getAArch64TargetFeatures(const Driver &D, const llvm::opt::ArgList &Args,
+                              std::vector<llvm::StringRef> &Features);
+
+std::string getAArch64TargetCPU(const llvm::opt::ArgList &Args,
+                                llvm::opt::Arg *&A);
+
+} // end namespace aarch64
+} // end namespace target
+} // end namespace driver
+} // end namespace clang
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_AARCH64_H
diff --git a/lib/Driver/ToolChains/Arch/ARM.cpp b/lib/Driver/ToolChains/Arch/ARM.cpp
new file mode 100644
index 000000000000..4eac97620114
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/ARM.cpp
@@ -0,0 +1,547 @@
+//===--- ARM.cpp - ARM (not AArch64) Helpers for Tools ----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ARM.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Options.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Option/ArgList.h"
+#include "llvm/Support/TargetParser.h"
+
+using namespace clang::driver;
+using namespace clang::driver::tools;
+using namespace clang;
+using namespace llvm::opt;
+
+// Get SubArch (vN).
+int arm::getARMSubArchVersionNumber(const llvm::Triple &Triple) {
+  llvm::StringRef Arch = Triple.getArchName();
+  return llvm::ARM::parseArchVersion(Arch);
+}
+
+// True if M-profile.
+bool arm::isARMMProfile(const llvm::Triple &Triple) {
+  llvm::StringRef Arch = Triple.getArchName();
+  unsigned Profile = llvm::ARM::parseArchProfile(Arch);
+  return Profile == llvm::ARM::PK_M;
+}
+
+// Get Arch/CPU from args.
+void arm::getARMArchCPUFromArgs(const ArgList &Args, llvm::StringRef &Arch,
+                                llvm::StringRef &CPU, bool FromAs) {
+  if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_mcpu_EQ))
+    CPU = A->getValue();
+  if (const Arg *A = Args.getLastArg(options::OPT_march_EQ))
+    Arch = A->getValue();
+  if (!FromAs)
+    return;
+
+  for (const Arg *A :
+       Args.filtered(options::OPT_Wa_COMMA, options::OPT_Xassembler)) {
+    StringRef Value = A->getValue();
+    if (Value.startswith("-mcpu="))
+      CPU = Value.substr(6);
+    if (Value.startswith("-march="))
+      Arch = Value.substr(7);
+  }
+}
+
+// Handle -mhwdiv=.
+// FIXME: Use ARMTargetParser.
+static void getARMHWDivFeatures(const Driver &D, const Arg *A,
+                                const ArgList &Args, StringRef HWDiv,
+                                std::vector<StringRef> &Features) {
+  unsigned HWDivID = llvm::ARM::parseHWDiv(HWDiv);
+  if (!llvm::ARM::getHWDivFeatures(HWDivID, Features))
+    D.Diag(clang::diag::err_drv_clang_unsupported) << A->getAsString(Args);
+}
+
+// Handle -mfpu=.
+static void getARMFPUFeatures(const Driver &D, const Arg *A,
+                              const ArgList &Args, StringRef FPU,
+                              std::vector<StringRef> &Features) {
+  unsigned FPUID = llvm::ARM::parseFPU(FPU);
+  if (!llvm::ARM::getFPUFeatures(FPUID, Features))
+    D.Diag(clang::diag::err_drv_clang_unsupported) << A->getAsString(Args);
+}
+
+// Decode ARM features from string like +[no]featureA+[no]featureB+...
+static bool DecodeARMFeatures(const Driver &D, StringRef text,
+                              std::vector<StringRef> &Features) {
+  SmallVector<StringRef, 8> Split;
+  text.split(Split, StringRef("+"), -1, false);
+
+  for (StringRef Feature : Split) {
+    StringRef FeatureName = llvm::ARM::getArchExtFeature(Feature);
+    if (!FeatureName.empty())
+      Features.push_back(FeatureName);
+    else
+      return false;
+  }
+  return true;
+}
+
+// Check if -march is valid by checking if it can be canonicalised and parsed.
+// getARMArch is used here instead of just checking the -march value in order
+// to handle -march=native correctly.
+static void checkARMArchName(const Driver &D, const Arg *A, const ArgList &Args,
+                             llvm::StringRef ArchName,
+                             std::vector<StringRef> &Features,
+                             const llvm::Triple &Triple) {
+  std::pair<StringRef, StringRef> Split = ArchName.split("+");
+
+  std::string MArch = arm::getARMArch(ArchName, Triple);
+  if (llvm::ARM::parseArch(MArch) == llvm::ARM::AK_INVALID ||
+      (Split.second.size() && !DecodeARMFeatures(D, Split.second, Features)))
+    D.Diag(clang::diag::err_drv_clang_unsupported) << A->getAsString(Args);
+}
+
+// Check -mcpu=. Needs ArchName to handle -mcpu=generic.
+static void checkARMCPUName(const Driver &D, const Arg *A, const ArgList &Args,
+                            llvm::StringRef CPUName, llvm::StringRef ArchName,
+                            std::vector<StringRef> &Features,
+                            const llvm::Triple &Triple) {
+  std::pair<StringRef, StringRef> Split = CPUName.split("+");
+
+  std::string CPU = arm::getARMTargetCPU(CPUName, ArchName, Triple);
+  if (arm::getLLVMArchSuffixForARM(CPU, ArchName, Triple).empty() ||
+      (Split.second.size() && !DecodeARMFeatures(D, Split.second, Features)))
+    D.Diag(clang::diag::err_drv_clang_unsupported) << A->getAsString(Args);
+}
+
+bool arm::useAAPCSForMachO(const llvm::Triple &T) {
+  // The backend is hardwired to assume AAPCS for M-class processors, ensure
+  // the frontend matches that.
+  return T.getEnvironment() == llvm::Triple::EABI ||
+         T.getOS() == llvm::Triple::UnknownOS || isARMMProfile(T);
+}
+
+// Select the float ABI as determined by -msoft-float, -mhard-float, and
+// -mfloat-abi=.
+arm::FloatABI arm::getARMFloatABI(const ToolChain &TC, const ArgList &Args) {
+  const Driver &D = TC.getDriver();
+  const llvm::Triple &Triple = TC.getEffectiveTriple();
+  auto SubArch = getARMSubArchVersionNumber(Triple);
+  arm::FloatABI ABI = FloatABI::Invalid;
+  if (Arg *A =
+          Args.getLastArg(options::OPT_msoft_float, options::OPT_mhard_float,
+                          options::OPT_mfloat_abi_EQ)) {
+    if (A->getOption().matches(options::OPT_msoft_float)) {
+      ABI = FloatABI::Soft;
+    } else if (A->getOption().matches(options::OPT_mhard_float)) {
+      ABI = FloatABI::Hard;
+    } else {
+      ABI = llvm::StringSwitch<arm::FloatABI>(A->getValue())
+                .Case("soft", FloatABI::Soft)
+                .Case("softfp", FloatABI::SoftFP)
+                .Case("hard", FloatABI::Hard)
+                .Default(FloatABI::Invalid);
+      if (ABI == FloatABI::Invalid && !StringRef(A->getValue()).empty()) {
+        D.Diag(diag::err_drv_invalid_mfloat_abi) << A->getAsString(Args);
+        ABI = FloatABI::Soft;
+      }
+    }
+
+    // It is incorrect to select hard float ABI on MachO platforms if the ABI is
+    // "apcs-gnu".
+    if (Triple.isOSBinFormatMachO() && !useAAPCSForMachO(Triple) &&
+        ABI == FloatABI::Hard) {
+      D.Diag(diag::err_drv_unsupported_opt_for_target) << A->getAsString(Args)
+                                                       << Triple.getArchName();
+    }
+  }
+
+  // If unspecified, choose the default based on the platform.
+  if (ABI == FloatABI::Invalid) {
+    switch (Triple.getOS()) {
+    case llvm::Triple::Darwin:
+    case llvm::Triple::MacOSX:
+    case llvm::Triple::IOS:
+    case llvm::Triple::TvOS: {
+      // Darwin defaults to "softfp" for v6 and v7.
+      ABI = (SubArch == 6 || SubArch == 7) ? FloatABI::SoftFP : FloatABI::Soft;
+      ABI = Triple.isWatchABI() ? FloatABI::Hard : ABI;
+      break;
+    }
+    case llvm::Triple::WatchOS:
+      ABI = FloatABI::Hard;
+      break;
+
+    // FIXME: this is invalid for WindowsCE
+    case llvm::Triple::Win32:
+      ABI = FloatABI::Hard;
+      break;
+
+    case llvm::Triple::FreeBSD:
+      switch (Triple.getEnvironment()) {
+      case llvm::Triple::GNUEABIHF:
+        ABI = FloatABI::Hard;
+        break;
+      default:
+        // FreeBSD defaults to soft float
+        ABI = FloatABI::Soft;
+        break;
+      }
+      break;
+
+    case llvm::Triple::OpenBSD:
+      ABI = FloatABI::Soft;
+      break;
+
+    default:
+      switch (Triple.getEnvironment()) {
+      case llvm::Triple::GNUEABIHF:
+      case llvm::Triple::MuslEABIHF:
+      case llvm::Triple::EABIHF:
+        ABI = FloatABI::Hard;
+        break;
+      case llvm::Triple::GNUEABI:
+      case llvm::Triple::MuslEABI:
+      case llvm::Triple::EABI:
+        // EABI is always AAPCS, and if it was not marked 'hard', it's softfp
+        ABI = FloatABI::SoftFP;
+        break;
+      case llvm::Triple::Android:
+        ABI = (SubArch == 7) ? FloatABI::SoftFP : FloatABI::Soft;
+        break;
+      default:
+        // Assume "soft", but warn the user we are guessing.
+        if (Triple.isOSBinFormatMachO() &&
+            Triple.getSubArch() == llvm::Triple::ARMSubArch_v7em)
+          ABI = FloatABI::Hard;
+        else
+          ABI = FloatABI::Soft;
+
+        if (Triple.getOS() != llvm::Triple::UnknownOS ||
+            !Triple.isOSBinFormatMachO())
+          D.Diag(diag::warn_drv_assuming_mfloat_abi_is) << "soft";
+        break;
+      }
+    }
+  }
+
+  assert(ABI != FloatABI::Invalid && "must select an ABI");
+  return ABI;
+}
+
+void arm::getARMTargetFeatures(const ToolChain &TC,
+                               const llvm::Triple &Triple,
+                               const ArgList &Args,
+                               ArgStringList &CmdArgs,
+                               std::vector<StringRef> &Features,
+                               bool ForAS) {
+  const Driver &D = TC.getDriver();
+
+  bool KernelOrKext =
+      Args.hasArg(options::OPT_mkernel, options::OPT_fapple_kext);
+  arm::FloatABI ABI = arm::getARMFloatABI(TC, Args);
+  const Arg *WaCPU = nullptr, *WaFPU = nullptr;
+  const Arg *WaHDiv = nullptr, *WaArch = nullptr;
+
+  if (!ForAS) {
+    // FIXME: Note, this is a hack, the LLVM backend doesn't actually use these
+    // yet (it uses the -mfloat-abi and -msoft-float options), and it is
+    // stripped out by the ARM target. We should probably pass this a new
+    // -target-option, which is handled by the -cc1/-cc1as invocation.
+    //
+    // FIXME2:  For consistency, it would be ideal if we set up the target
+    // machine state the same when using the frontend or the assembler. We don't
+    // currently do that for the assembler, we pass the options directly to the
+    // backend and never even instantiate the frontend TargetInfo. If we did,
+    // and used its handleTargetFeatures hook, then we could ensure the
+    // assembler and the frontend behave the same.
+
+    // Use software floating point operations?
+    if (ABI == arm::FloatABI::Soft)
+      Features.push_back("+soft-float");
+
+    // Use software floating point argument passing?
+    if (ABI != arm::FloatABI::Hard)
+      Features.push_back("+soft-float-abi");
+  } else {
+    // Here, we make sure that -Wa,-mfpu/cpu/arch/hwdiv will be passed down
+    // to the assembler correctly.
+    for (const Arg *A :
+         Args.filtered(options::OPT_Wa_COMMA, options::OPT_Xassembler)) {
+      StringRef Value = A->getValue();
+      if (Value.startswith("-mfpu=")) {
+        WaFPU = A;
+      } else if (Value.startswith("-mcpu=")) {
+        WaCPU = A;
+      } else if (Value.startswith("-mhwdiv=")) {
+        WaHDiv = A;
+      } else if (Value.startswith("-march=")) {
+        WaArch = A;
+      }
+    }
+  }
+
+  // Check -march. ClangAs gives preference to -Wa,-march=.
+  const Arg *ArchArg = Args.getLastArg(options::OPT_march_EQ);
+  StringRef ArchName;
+  if (WaArch) {
+    if (ArchArg)
+      D.Diag(clang::diag::warn_drv_unused_argument)
+          << ArchArg->getAsString(Args);
+    ArchName = StringRef(WaArch->getValue()).substr(7);
+    checkARMArchName(D, WaArch, Args, ArchName, Features, Triple);
+    // FIXME: Set Arch.
+    D.Diag(clang::diag::warn_drv_unused_argument) << WaArch->getAsString(Args);
+  } else if (ArchArg) {
+    ArchName = ArchArg->getValue();
+    checkARMArchName(D, ArchArg, Args, ArchName, Features, Triple);
+  }
+
+  // Check -mcpu. ClangAs gives preference to -Wa,-mcpu=.
+  const Arg *CPUArg = Args.getLastArg(options::OPT_mcpu_EQ);
+  StringRef CPUName;
+  if (WaCPU) {
+    if (CPUArg)
+      D.Diag(clang::diag::warn_drv_unused_argument)
+          << CPUArg->getAsString(Args);
+    CPUName = StringRef(WaCPU->getValue()).substr(6);
+    checkARMCPUName(D, WaCPU, Args, CPUName, ArchName, Features, Triple);
+  } else if (CPUArg) {
+    CPUName = CPUArg->getValue();
+    checkARMCPUName(D, CPUArg, Args, CPUName, ArchName, Features, Triple);
+  }
+
+  // Add CPU features for generic CPUs
+  if (CPUName == "native") {
+    llvm::StringMap<bool> HostFeatures;
+    if (llvm::sys::getHostCPUFeatures(HostFeatures))
+      for (auto &F : HostFeatures)
+        Features.push_back(
+            Args.MakeArgString((F.second ? "+" : "-") + F.first()));
+  }
+
+  // Honor -mfpu=. ClangAs gives preference to -Wa,-mfpu=.
+  const Arg *FPUArg = Args.getLastArg(options::OPT_mfpu_EQ);
+  if (WaFPU) {
+    if (FPUArg)
+      D.Diag(clang::diag::warn_drv_unused_argument)
+          << FPUArg->getAsString(Args);
+    getARMFPUFeatures(D, WaFPU, Args, StringRef(WaFPU->getValue()).substr(6),
+                      Features);
+  } else if (FPUArg) {
+    getARMFPUFeatures(D, FPUArg, Args, FPUArg->getValue(), Features);
+  }
+
+  // Honor -mhwdiv=. ClangAs gives preference to -Wa,-mhwdiv=.
+  const Arg *HDivArg = Args.getLastArg(options::OPT_mhwdiv_EQ);
+  if (WaHDiv) {
+    if (HDivArg)
+      D.Diag(clang::diag::warn_drv_unused_argument)
+          << HDivArg->getAsString(Args);
+    getARMHWDivFeatures(D, WaHDiv, Args,
+                        StringRef(WaHDiv->getValue()).substr(8), Features);
+  } else if (HDivArg)
+    getARMHWDivFeatures(D, HDivArg, Args, HDivArg->getValue(), Features);
+
+  // Setting -msoft-float effectively disables NEON because of the GCC
+  // implementation, although the same isn't true of VFP or VFP3.
+  if (ABI == arm::FloatABI::Soft) {
+    Features.push_back("-neon");
+    // Also need to explicitly disable features which imply NEON.
+    Features.push_back("-crypto");
+  }
+
+  // En/disable crc code generation.
+  if (Arg *A = Args.getLastArg(options::OPT_mcrc, options::OPT_mnocrc)) {
+    if (A->getOption().matches(options::OPT_mcrc))
+      Features.push_back("+crc");
+    else
+      Features.push_back("-crc");
+  }
+
+  // Look for the last occurrence of -mlong-calls or -mno-long-calls. If
+  // neither options are specified, see if we are compiling for kernel/kext and
+  // decide whether to pass "+long-calls" based on the OS and its version.
+  if (Arg *A = Args.getLastArg(options::OPT_mlong_calls,
+                               options::OPT_mno_long_calls)) {
+    if (A->getOption().matches(options::OPT_mlong_calls))
+      Features.push_back("+long-calls");
+  } else if (KernelOrKext && (!Triple.isiOS() || Triple.isOSVersionLT(6)) &&
+             !Triple.isWatchOS()) {
+      Features.push_back("+long-calls");
+  }
+
+  // Generate execute-only output (no data access to code sections).
+  // This only makes sense for the compiler, not for the assembler.
+  if (!ForAS) {
+    // Supported only on ARMv6T2 and ARMv7 and above.
+    // Cannot be combined with -mno-movt or -mlong-calls
+    if (Arg *A = Args.getLastArg(options::OPT_mexecute_only, options::OPT_mno_execute_only)) {
+      if (A->getOption().matches(options::OPT_mexecute_only)) {
+        if (getARMSubArchVersionNumber(Triple) < 7 &&
+            llvm::ARM::parseArch(Triple.getArchName()) != llvm::ARM::AK_ARMV6T2)
+              D.Diag(diag::err_target_unsupported_execute_only) << Triple.getArchName();
+        else if (Arg *B = Args.getLastArg(options::OPT_mno_movt))
+          D.Diag(diag::err_opt_not_valid_with_opt) << A->getAsString(Args) << B->getAsString(Args);
+        // Long calls create constant pool entries and have not yet been fixed up
+        // to play nicely with execute-only. Hence, they cannot be used in
+        // execute-only code for now
+        else if (Arg *B = Args.getLastArg(options::OPT_mlong_calls, options::OPT_mno_long_calls)) {
+          if (B->getOption().matches(options::OPT_mlong_calls))
+            D.Diag(diag::err_opt_not_valid_with_opt) << A->getAsString(Args) << B->getAsString(Args);
+        }
+
+        CmdArgs.push_back("-backend-option");
+        CmdArgs.push_back("-arm-execute-only");
+      }
+    }
+  }
+
+  // Kernel code has more strict alignment requirements.
+  if (KernelOrKext)
+    Features.push_back("+strict-align");
+  else if (Arg *A = Args.getLastArg(options::OPT_mno_unaligned_access,
+                                    options::OPT_munaligned_access)) {
+    if (A->getOption().matches(options::OPT_munaligned_access)) {
+      // No v6M core supports unaligned memory access (v6M ARM ARM A3.2).
+      if (Triple.getSubArch() == llvm::Triple::SubArchType::ARMSubArch_v6m)
+        D.Diag(diag::err_target_unsupported_unaligned) << "v6m";
+      // v8M Baseline follows on from v6M, so doesn't support unaligned memory
+      // access either.
+      else if (Triple.getSubArch() == llvm::Triple::SubArchType::ARMSubArch_v8m_baseline)
+        D.Diag(diag::err_target_unsupported_unaligned) << "v8m.base";
+    } else
+      Features.push_back("+strict-align");
+  } else {
+    // Assume pre-ARMv6 doesn't support unaligned accesses.
+    //
+    // ARMv6 may or may not support unaligned accesses depending on the
+    // SCTLR.U bit, which is architecture-specific. We assume ARMv6
+    // Darwin and NetBSD targets support unaligned accesses, and others don't.
+    //
+    // ARMv7 always has SCTLR.U set to 1, but it has a new SCTLR.A bit
+    // which raises an alignment fault on unaligned accesses. Linux
+    // defaults this bit to 0 and handles it as a system-wide (not
+    // per-process) setting. It is therefore safe to assume that ARMv7+
+    // Linux targets support unaligned accesses. The same goes for NaCl.
+    //
+    // The above behavior is consistent with GCC.
+    int VersionNum = getARMSubArchVersionNumber(Triple);
+    if (Triple.isOSDarwin() || Triple.isOSNetBSD()) {
+      if (VersionNum < 6 ||
+          Triple.getSubArch() == llvm::Triple::SubArchType::ARMSubArch_v6m)
+        Features.push_back("+strict-align");
+    } else if (Triple.isOSLinux() || Triple.isOSNaCl()) {
+      if (VersionNum < 7)
+        Features.push_back("+strict-align");
+    } else
+      Features.push_back("+strict-align");
+  }
+
+  // llvm does not support reserving registers in general. There is support
+  // for reserving r9 on ARM though (defined as a platform-specific register
+  // in ARM EABI).
+  if (Args.hasArg(options::OPT_ffixed_r9))
+    Features.push_back("+reserve-r9");
+
+  // The kext linker doesn't know how to deal with movw/movt.
+  if (KernelOrKext || Args.hasArg(options::OPT_mno_movt))
+    Features.push_back("+no-movt");
+
+  if (Args.hasArg(options::OPT_mno_neg_immediates))
+    Features.push_back("+no-neg-immediates");
+}
+
+const std::string arm::getARMArch(StringRef Arch, const llvm::Triple &Triple) {
+  std::string MArch;
+  if (!Arch.empty())
+    MArch = Arch;
+  else
+    MArch = Triple.getArchName();
+  MArch = StringRef(MArch).split("+").first.lower();
+
+  // Handle -march=native.
+  if (MArch == "native") {
+    std::string CPU = llvm::sys::getHostCPUName();
+    if (CPU != "generic") {
+      // Translate the native cpu into the architecture suffix for that CPU.
+      StringRef Suffix = arm::getLLVMArchSuffixForARM(CPU, MArch, Triple);
+      // If there is no valid architecture suffix for this CPU we don't know how
+      // to handle it, so return no architecture.
+      if (Suffix.empty())
+        MArch = "";
+      else
+        MArch = std::string("arm") + Suffix.str();
+    }
+  }
+
+  return MArch;
+}
+
+/// Get the (LLVM) name of the minimum ARM CPU for the arch we are targeting.
+StringRef arm::getARMCPUForMArch(StringRef Arch, const llvm::Triple &Triple) {
+  std::string MArch = getARMArch(Arch, Triple);
+  // getARMCPUForArch defaults to the triple if MArch is empty, but empty MArch
+  // here means an -march=native that we can't handle, so instead return no CPU.
+  if (MArch.empty())
+    return StringRef();
+
+  // We need to return an empty string here on invalid MArch values as the
+  // various places that call this function can't cope with a null result.
+  return Triple.getARMCPUForArch(MArch);
+}
+
+/// getARMTargetCPU - Get the (LLVM) name of the ARM cpu we are targeting.
+std::string arm::getARMTargetCPU(StringRef CPU, StringRef Arch,
+                                 const llvm::Triple &Triple) {
+  // FIXME: Warn on inconsistent use of -mcpu and -march.
+  // If we have -mcpu=, use that.
+  if (!CPU.empty()) {
+    std::string MCPU = StringRef(CPU).split("+").first.lower();
+    // Handle -mcpu=native.
+    if (MCPU == "native")
+      return llvm::sys::getHostCPUName();
+    else
+      return MCPU;
+  }
+
+  return getARMCPUForMArch(Arch, Triple);
+}
+
+/// getLLVMArchSuffixForARM - Get the LLVM arch name to use for a particular
+/// CPU  (or Arch, if CPU is generic).
+// FIXME: This is redundant with -mcpu, why does LLVM use this.
+StringRef arm::getLLVMArchSuffixForARM(StringRef CPU, StringRef Arch,
+                                       const llvm::Triple &Triple) {
+  unsigned ArchKind;
+  if (CPU == "generic") {
+    std::string ARMArch = tools::arm::getARMArch(Arch, Triple);
+    ArchKind = llvm::ARM::parseArch(ARMArch);
+    if (ArchKind == llvm::ARM::AK_INVALID)
+      // In case of generic Arch, i.e. "arm",
+      // extract arch from default cpu of the Triple
+      ArchKind = llvm::ARM::parseCPUArch(Triple.getARMCPUForArch(ARMArch));
+  } else {
+    // FIXME: horrible hack to get around the fact that Cortex-A7 is only an
+    // armv7k triple if it's actually been specified via "-arch armv7k".
+    ArchKind = (Arch == "armv7k" || Arch == "thumbv7k")
+                          ? (unsigned)llvm::ARM::AK_ARMV7K
+                          : llvm::ARM::parseCPUArch(CPU);
+  }
+  if (ArchKind == llvm::ARM::AK_INVALID)
+    return "";
+  return llvm::ARM::getSubArch(ArchKind);
+}
+
+void arm::appendEBLinkFlags(const ArgList &Args, ArgStringList &CmdArgs,
+                            const llvm::Triple &Triple) {
+  if (Args.hasArg(options::OPT_r))
+    return;
+
+  // ARMv7 (and later) and ARMv6-M do not support BE-32, so instruct the linker
+  // to generate BE-8 executables.
+  if (arm::getARMSubArchVersionNumber(Triple) >= 7 || arm::isARMMProfile(Triple))
+    CmdArgs.push_back("--be8");
+}
diff --git a/lib/Driver/ToolChains/Arch/ARM.h b/lib/Driver/ToolChains/Arch/ARM.h
new file mode 100644
index 000000000000..52afaab762d0
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/ARM.h
@@ -0,0 +1,60 @@
+//===--- ARM.h - ARM-specific (not AArch64) Tool Helpers --------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_ARM_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_ARM_H
+
+#include "clang/Driver/ToolChain.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/Option/Option.h"
+#include <string>
+#include <vector>
+
+namespace clang {
+namespace driver {
+namespace tools {
+namespace arm {
+
+std::string getARMTargetCPU(StringRef CPU, llvm::StringRef Arch,
+                            const llvm::Triple &Triple);
+const std::string getARMArch(llvm::StringRef Arch, const llvm::Triple &Triple);
+StringRef getARMCPUForMArch(llvm::StringRef Arch, const llvm::Triple &Triple);
+StringRef getLLVMArchSuffixForARM(llvm::StringRef CPU, llvm::StringRef Arch,
+                                  const llvm::Triple &Triple);
+
+void appendEBLinkFlags(const llvm::opt::ArgList &Args,
+                       llvm::opt::ArgStringList &CmdArgs,
+                       const llvm::Triple &Triple);
+enum class FloatABI {
+  Invalid,
+  Soft,
+  SoftFP,
+  Hard,
+};
+
+FloatABI getARMFloatABI(const ToolChain &TC, const llvm::opt::ArgList &Args);
+
+bool useAAPCSForMachO(const llvm::Triple &T);
+void getARMArchCPUFromArgs(const llvm::opt::ArgList &Args,
+                           llvm::StringRef &Arch, llvm::StringRef &CPU,
+                           bool FromAs = false);
+void getARMTargetFeatures(const ToolChain &TC, const llvm::Triple &Triple,
+                          const llvm::opt::ArgList &Args,
+                          llvm::opt::ArgStringList &CmdArgs,
+                          std::vector<llvm::StringRef> &Features, bool ForAS);
+int getARMSubArchVersionNumber(const llvm::Triple &Triple);
+bool isARMMProfile(const llvm::Triple &Triple);
+
+} // end namespace arm
+} // end namespace tools
+} // end namespace driver
+} // end namespace clang
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_ARM_H
diff --git a/lib/Driver/ToolChains/Arch/Mips.cpp b/lib/Driver/ToolChains/Arch/Mips.cpp
new file mode 100644
index 000000000000..cd791af83220
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/Mips.cpp
@@ -0,0 +1,403 @@
+//===--- Mips.cpp - Tools Implementations -----------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Mips.h"
+#include "ToolChains/CommonArgs.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Options.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Option/ArgList.h"
+
+using namespace clang::driver;
+using namespace clang::driver::tools;
+using namespace clang;
+using namespace llvm::opt;
+
+bool tools::isMipsArch(llvm::Triple::ArchType Arch) {
+  return Arch == llvm::Triple::mips || Arch == llvm::Triple::mipsel ||
+         Arch == llvm::Triple::mips64 || Arch == llvm::Triple::mips64el;
+}
+
+// Get CPU and ABI names. They are not independent
+// so we have to calculate them together.
+void mips::getMipsCPUAndABI(const ArgList &Args, const llvm::Triple &Triple,
+                            StringRef &CPUName, StringRef &ABIName) {
+  const char *DefMips32CPU = "mips32r2";
+  const char *DefMips64CPU = "mips64r2";
+
+  // MIPS32r6 is the default for mips(el)?-img-linux-gnu and MIPS64r6 is the
+  // default for mips64(el)?-img-linux-gnu.
+  if (Triple.getVendor() == llvm::Triple::ImaginationTechnologies &&
+      Triple.getEnvironment() == llvm::Triple::GNU) {
+    DefMips32CPU = "mips32r6";
+    DefMips64CPU = "mips64r6";
+  }
+
+  // MIPS64r6 is the default for Android MIPS64 (mips64el-linux-android).
+  if (Triple.isAndroid()) {
+    DefMips32CPU = "mips32";
+    DefMips64CPU = "mips64r6";
+  }
+
+  // MIPS3 is the default for mips64*-unknown-openbsd.
+  if (Triple.getOS() == llvm::Triple::OpenBSD)
+    DefMips64CPU = "mips3";
+
+  if (Arg *A = Args.getLastArg(clang::driver::options::OPT_march_EQ,
+                               options::OPT_mcpu_EQ))
+    CPUName = A->getValue();
+
+  if (Arg *A = Args.getLastArg(options::OPT_mabi_EQ)) {
+    ABIName = A->getValue();
+    // Convert a GNU style Mips ABI name to the name
+    // accepted by LLVM Mips backend.
+    ABIName = llvm::StringSwitch<llvm::StringRef>(ABIName)
+                  .Case("32", "o32")
+                  .Case("64", "n64")
+                  .Default(ABIName);
+  }
+
+  // Setup default CPU and ABI names.
+  if (CPUName.empty() && ABIName.empty()) {
+    switch (Triple.getArch()) {
+    default:
+      llvm_unreachable("Unexpected triple arch name");
+    case llvm::Triple::mips:
+    case llvm::Triple::mipsel:
+      CPUName = DefMips32CPU;
+      break;
+    case llvm::Triple::mips64:
+    case llvm::Triple::mips64el:
+      CPUName = DefMips64CPU;
+      break;
+    }
+  }
+
+  if (ABIName.empty() &&
+      (Triple.getVendor() == llvm::Triple::MipsTechnologies ||
+       Triple.getVendor() == llvm::Triple::ImaginationTechnologies)) {
+    ABIName = llvm::StringSwitch<const char *>(CPUName)
+                  .Case("mips1", "o32")
+                  .Case("mips2", "o32")
+                  .Case("mips3", "n64")
+                  .Case("mips4", "n64")
+                  .Case("mips5", "n64")
+                  .Case("mips32", "o32")
+                  .Case("mips32r2", "o32")
+                  .Case("mips32r3", "o32")
+                  .Case("mips32r5", "o32")
+                  .Case("mips32r6", "o32")
+                  .Case("mips64", "n64")
+                  .Case("mips64r2", "n64")
+                  .Case("mips64r3", "n64")
+                  .Case("mips64r5", "n64")
+                  .Case("mips64r6", "n64")
+                  .Case("octeon", "n64")
+                  .Case("p5600", "o32")
+                  .Default("");
+  }
+
+  if (ABIName.empty()) {
+    // Deduce ABI name from the target triple.
+    if (Triple.getArch() == llvm::Triple::mips ||
+        Triple.getArch() == llvm::Triple::mipsel)
+      ABIName = "o32";
+    else
+      ABIName = "n64";
+  }
+
+  if (CPUName.empty()) {
+    // Deduce CPU name from ABI name.
+    CPUName = llvm::StringSwitch<const char *>(ABIName)
+                  .Case("o32", DefMips32CPU)
+                  .Cases("n32", "n64", DefMips64CPU)
+                  .Default("");
+  }
+
+  // FIXME: Warn on inconsistent use of -march and -mabi.
+}
+
+std::string mips::getMipsABILibSuffix(const ArgList &Args,
+                                      const llvm::Triple &Triple) {
+  StringRef CPUName, ABIName;
+  tools::mips::getMipsCPUAndABI(Args, Triple, CPUName, ABIName);
+  return llvm::StringSwitch<std::string>(ABIName)
+      .Case("o32", "")
+      .Case("n32", "32")
+      .Case("n64", "64");
+}
+
+// Convert ABI name to the GNU tools acceptable variant.
+StringRef mips::getGnuCompatibleMipsABIName(StringRef ABI) {
+  return llvm::StringSwitch<llvm::StringRef>(ABI)
+      .Case("o32", "32")
+      .Case("n64", "64")
+      .Default(ABI);
+}
+
+// Select the MIPS float ABI as determined by -msoft-float, -mhard-float,
+// and -mfloat-abi=.
+mips::FloatABI mips::getMipsFloatABI(const Driver &D, const ArgList &Args) {
+  mips::FloatABI ABI = mips::FloatABI::Invalid;
+  if (Arg *A =
+          Args.getLastArg(options::OPT_msoft_float, options::OPT_mhard_float,
+                          options::OPT_mfloat_abi_EQ)) {
+    if (A->getOption().matches(options::OPT_msoft_float))
+      ABI = mips::FloatABI::Soft;
+    else if (A->getOption().matches(options::OPT_mhard_float))
+      ABI = mips::FloatABI::Hard;
+    else {
+      ABI = llvm::StringSwitch<mips::FloatABI>(A->getValue())
+                .Case("soft", mips::FloatABI::Soft)
+                .Case("hard", mips::FloatABI::Hard)
+                .Default(mips::FloatABI::Invalid);
+      if (ABI == mips::FloatABI::Invalid && !StringRef(A->getValue()).empty()) {
+        D.Diag(clang::diag::err_drv_invalid_mfloat_abi) << A->getAsString(Args);
+        ABI = mips::FloatABI::Hard;
+      }
+    }
+  }
+
+  // If unspecified, choose the default based on the platform.
+  if (ABI == mips::FloatABI::Invalid) {
+    // Assume "hard", because it's a default value used by gcc.
+    // When we start to recognize specific target MIPS processors,
+    // we will be able to select the default more correctly.
+    ABI = mips::FloatABI::Hard;
+  }
+
+  assert(ABI != mips::FloatABI::Invalid && "must select an ABI");
+  return ABI;
+}
+
+void mips::getMIPSTargetFeatures(const Driver &D, const llvm::Triple &Triple,
+                                 const ArgList &Args,
+                                 std::vector<StringRef> &Features) {
+  StringRef CPUName;
+  StringRef ABIName;
+  getMipsCPUAndABI(Args, Triple, CPUName, ABIName);
+  ABIName = getGnuCompatibleMipsABIName(ABIName);
+
+  // Historically, PIC code for MIPS was associated with -mabicalls, a.k.a
+  // SVR4 abicalls. Static code does not use SVR4 calling sequences. An ABI
+  // extension was developed by Richard Sandiford & Code Sourcery to support
+  // static code calling PIC code (CPIC). For O32 and N32 this means we have
+  // several combinations of PIC/static and abicalls. Pure static, static
+  // with the CPIC extension, and pure PIC code.
+
+  // At final link time, O32 and N32 with CPIC will have another section
+  // added to the binary which contains the stub functions to perform
+  // any fixups required for PIC code.
+
+  // For N64, the situation is more regular: code can either be static
+  // (non-abicalls) or PIC (abicalls). GCC has traditionally picked PIC code
+  // code for N64. Since Clang has already built the relocation model portion
+  // of the commandline, we pick add +noabicalls feature in the N64 static
+  // case.
+
+  // The is another case to be accounted for: -msym32, which enforces that all
+  // symbols have 32 bits in size. In this case, N64 can in theory use CPIC
+  // but it is unsupported.
+
+  // The combinations for N64 are:
+  // a) Static without abicalls and 64bit symbols.
+  // b) Static with abicalls and 32bit symbols.
+  // c) PIC with abicalls and 64bit symbols.
+
+  // For case (a) we need to add +noabicalls for N64.
+
+  bool IsN64 = ABIName == "64";
+  bool NonPIC = false;
+
+  Arg *LastPICArg = Args.getLastArg(options::OPT_fPIC, options::OPT_fno_PIC,
+                                    options::OPT_fpic, options::OPT_fno_pic,
+                                    options::OPT_fPIE, options::OPT_fno_PIE,
+                                    options::OPT_fpie, options::OPT_fno_pie);
+  if (LastPICArg) {
+    Option O = LastPICArg->getOption();
+    NonPIC =
+        (O.matches(options::OPT_fno_PIC) || O.matches(options::OPT_fno_pic) ||
+         O.matches(options::OPT_fno_PIE) || O.matches(options::OPT_fno_pie));
+  }
+
+  if (IsN64 && NonPIC) {
+    Features.push_back("+noabicalls");
+  } else {
+    AddTargetFeature(Args, Features, options::OPT_mno_abicalls,
+                     options::OPT_mabicalls, "noabicalls");
+  }
+
+  mips::FloatABI FloatABI = mips::getMipsFloatABI(D, Args);
+  if (FloatABI == mips::FloatABI::Soft) {
+    // FIXME: Note, this is a hack. We need to pass the selected float
+    // mode to the MipsTargetInfoBase to define appropriate macros there.
+    // Now it is the only method.
+    Features.push_back("+soft-float");
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_mnan_EQ)) {
+    StringRef Val = StringRef(A->getValue());
+    if (Val == "2008") {
+      if (mips::getSupportedNanEncoding(CPUName) & mips::Nan2008)
+        Features.push_back("+nan2008");
+      else {
+        Features.push_back("-nan2008");
+        D.Diag(diag::warn_target_unsupported_nan2008) << CPUName;
+      }
+    } else if (Val == "legacy") {
+      if (mips::getSupportedNanEncoding(CPUName) & mips::NanLegacy)
+        Features.push_back("-nan2008");
+      else {
+        Features.push_back("+nan2008");
+        D.Diag(diag::warn_target_unsupported_nanlegacy) << CPUName;
+      }
+    } else
+      D.Diag(diag::err_drv_unsupported_option_argument)
+          << A->getOption().getName() << Val;
+  }
+
+  AddTargetFeature(Args, Features, options::OPT_msingle_float,
+                   options::OPT_mdouble_float, "single-float");
+  AddTargetFeature(Args, Features, options::OPT_mips16, options::OPT_mno_mips16,
+                   "mips16");
+  AddTargetFeature(Args, Features, options::OPT_mmicromips,
+                   options::OPT_mno_micromips, "micromips");
+  AddTargetFeature(Args, Features, options::OPT_mdsp, options::OPT_mno_dsp,
+                   "dsp");
+  AddTargetFeature(Args, Features, options::OPT_mdspr2, options::OPT_mno_dspr2,
+                   "dspr2");
+  AddTargetFeature(Args, Features, options::OPT_mmsa, options::OPT_mno_msa,
+                   "msa");
+
+  // Add the last -mfp32/-mfpxx/-mfp64, if none are given and the ABI is O32
+  // pass -mfpxx, or if none are given and fp64a is default, pass fp64 and
+  // nooddspreg.
+  if (Arg *A = Args.getLastArg(options::OPT_mfp32, options::OPT_mfpxx,
+                               options::OPT_mfp64)) {
+    if (A->getOption().matches(options::OPT_mfp32))
+      Features.push_back(Args.MakeArgString("-fp64"));
+    else if (A->getOption().matches(options::OPT_mfpxx)) {
+      Features.push_back(Args.MakeArgString("+fpxx"));
+      Features.push_back(Args.MakeArgString("+nooddspreg"));
+    } else
+      Features.push_back(Args.MakeArgString("+fp64"));
+  } else if (mips::shouldUseFPXX(Args, Triple, CPUName, ABIName, FloatABI)) {
+    Features.push_back(Args.MakeArgString("+fpxx"));
+    Features.push_back(Args.MakeArgString("+nooddspreg"));
+  } else if (mips::isFP64ADefault(Triple, CPUName)) {
+    Features.push_back(Args.MakeArgString("+fp64"));
+    Features.push_back(Args.MakeArgString("+nooddspreg"));
+  }
+
+  AddTargetFeature(Args, Features, options::OPT_mno_odd_spreg,
+                   options::OPT_modd_spreg, "nooddspreg");
+}
+
+mips::NanEncoding mips::getSupportedNanEncoding(StringRef &CPU) {
+  // Strictly speaking, mips32r2 and mips64r2 are NanLegacy-only since Nan2008
+  // was first introduced in Release 3. However, other compilers have
+  // traditionally allowed it for Release 2 so we should do the same.
+  return (NanEncoding)llvm::StringSwitch<int>(CPU)
+      .Case("mips1", NanLegacy)
+      .Case("mips2", NanLegacy)
+      .Case("mips3", NanLegacy)
+      .Case("mips4", NanLegacy)
+      .Case("mips5", NanLegacy)
+      .Case("mips32", NanLegacy)
+      .Case("mips32r2", NanLegacy | Nan2008)
+      .Case("mips32r3", NanLegacy | Nan2008)
+      .Case("mips32r5", NanLegacy | Nan2008)
+      .Case("mips32r6", Nan2008)
+      .Case("mips64", NanLegacy)
+      .Case("mips64r2", NanLegacy | Nan2008)
+      .Case("mips64r3", NanLegacy | Nan2008)
+      .Case("mips64r5", NanLegacy | Nan2008)
+      .Case("mips64r6", Nan2008)
+      .Default(NanLegacy);
+}
+
+bool mips::hasCompactBranches(StringRef &CPU) {
+  // mips32r6 and mips64r6 have compact branches.
+  return llvm::StringSwitch<bool>(CPU)
+      .Case("mips32r6", true)
+      .Case("mips64r6", true)
+      .Default(false);
+}
+
+bool mips::hasMipsAbiArg(const ArgList &Args, const char *Value) {
+  Arg *A = Args.getLastArg(options::OPT_mabi_EQ);
+  return A && (A->getValue() == StringRef(Value));
+}
+
+bool mips::isUCLibc(const ArgList &Args) {
+  Arg *A = Args.getLastArg(options::OPT_m_libc_Group);
+  return A && A->getOption().matches(options::OPT_muclibc);
+}
+
+bool mips::isNaN2008(const ArgList &Args, const llvm::Triple &Triple) {
+  if (Arg *NaNArg = Args.getLastArg(options::OPT_mnan_EQ))
+    return llvm::StringSwitch<bool>(NaNArg->getValue())
+        .Case("2008", true)
+        .Case("legacy", false)
+        .Default(false);
+
+  // NaN2008 is the default for MIPS32r6/MIPS64r6.
+  return llvm::StringSwitch<bool>(getCPUName(Args, Triple))
+      .Cases("mips32r6", "mips64r6", true)
+      .Default(false);
+
+  return false;
+}
+
+bool mips::isFP64ADefault(const llvm::Triple &Triple, StringRef CPUName) {
+  if (!Triple.isAndroid())
+    return false;
+
+  // Android MIPS32R6 defaults to FP64A.
+  return llvm::StringSwitch<bool>(CPUName)
+      .Case("mips32r6", true)
+      .Default(false);
+}
+
+bool mips::isFPXXDefault(const llvm::Triple &Triple, StringRef CPUName,
+                         StringRef ABIName, mips::FloatABI FloatABI) {
+  if (Triple.getVendor() != llvm::Triple::ImaginationTechnologies &&
+      Triple.getVendor() != llvm::Triple::MipsTechnologies &&
+      !Triple.isAndroid())
+    return false;
+
+  if (ABIName != "32")
+    return false;
+
+  // FPXX shouldn't be used if either -msoft-float or -mfloat-abi=soft is
+  // present.
+  if (FloatABI == mips::FloatABI::Soft)
+    return false;
+
+  return llvm::StringSwitch<bool>(CPUName)
+      .Cases("mips2", "mips3", "mips4", "mips5", true)
+      .Cases("mips32", "mips32r2", "mips32r3", "mips32r5", true)
+      .Cases("mips64", "mips64r2", "mips64r3", "mips64r5", true)
+      .Default(false);
+}
+
+bool mips::shouldUseFPXX(const ArgList &Args, const llvm::Triple &Triple,
+                         StringRef CPUName, StringRef ABIName,
+                         mips::FloatABI FloatABI) {
+  bool UseFPXX = isFPXXDefault(Triple, CPUName, ABIName, FloatABI);
+
+  // FPXX shouldn't be used if -msingle-float is present.
+  if (Arg *A = Args.getLastArg(options::OPT_msingle_float,
+                               options::OPT_mdouble_float))
+    if (A->getOption().matches(options::OPT_msingle_float))
+      UseFPXX = false;
+
+  return UseFPXX;
+}
diff --git a/lib/Driver/ToolChains/Arch/Mips.h b/lib/Driver/ToolChains/Arch/Mips.h
new file mode 100644
index 000000000000..0b788660948c
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/Mips.h
@@ -0,0 +1,62 @@
+//===--- Mips.h - Mips-specific Tool Helpers ----------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_MIPS_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_MIPS_H
+
+#include "clang/Driver/Driver.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/Option/Option.h"
+#include <string>
+#include <vector>
+
+namespace clang {
+namespace driver {
+namespace tools {
+
+bool isMipsArch(llvm::Triple::ArchType Arch);
+
+namespace mips {
+typedef enum { NanLegacy = 1, Nan2008 = 2 } NanEncoding;
+
+enum class FloatABI {
+  Invalid,
+  Soft,
+  Hard,
+};
+
+NanEncoding getSupportedNanEncoding(StringRef &CPU);
+bool hasCompactBranches(StringRef &CPU);
+void getMipsCPUAndABI(const llvm::opt::ArgList &Args,
+                      const llvm::Triple &Triple, StringRef &CPUName,
+                      StringRef &ABIName);
+void getMIPSTargetFeatures(const Driver &D, const llvm::Triple &Triple,
+                           const llvm::opt::ArgList &Args,
+                           std::vector<StringRef> &Features);
+StringRef getGnuCompatibleMipsABIName(StringRef ABI);
+mips::FloatABI getMipsFloatABI(const Driver &D, const llvm::opt::ArgList &Args);
+std::string getMipsABILibSuffix(const llvm::opt::ArgList &Args,
+                                const llvm::Triple &Triple);
+bool hasMipsAbiArg(const llvm::opt::ArgList &Args, const char *Value);
+bool isUCLibc(const llvm::opt::ArgList &Args);
+bool isNaN2008(const llvm::opt::ArgList &Args, const llvm::Triple &Triple);
+bool isFP64ADefault(const llvm::Triple &Triple, StringRef CPUName);
+bool isFPXXDefault(const llvm::Triple &Triple, StringRef CPUName,
+                   StringRef ABIName, mips::FloatABI FloatABI);
+bool shouldUseFPXX(const llvm::opt::ArgList &Args, const llvm::Triple &Triple,
+                   StringRef CPUName, StringRef ABIName,
+                   mips::FloatABI FloatABI);
+
+} // end namespace mips
+} // end namespace target
+} // end namespace driver
+} // end namespace clang
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_MIPS_H
diff --git a/lib/Driver/ToolChains/Arch/PPC.cpp b/lib/Driver/ToolChains/Arch/PPC.cpp
new file mode 100644
index 000000000000..541323127f9a
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/PPC.cpp
@@ -0,0 +1,131 @@
+//===--- PPC.cpp - PPC Helpers for Tools ------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "PPC.h"
+#include "ToolChains/CommonArgs.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Options.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Option/ArgList.h"
+
+using namespace clang::driver;
+using namespace clang::driver::tools;
+using namespace clang;
+using namespace llvm::opt;
+
+/// getPPCTargetCPU - Get the (LLVM) name of the PowerPC cpu we are targeting.
+std::string ppc::getPPCTargetCPU(const ArgList &Args) {
+  if (Arg *A = Args.getLastArg(clang::driver::options::OPT_mcpu_EQ)) {
+    StringRef CPUName = A->getValue();
+
+    if (CPUName == "native") {
+      std::string CPU = llvm::sys::getHostCPUName();
+      if (!CPU.empty() && CPU != "generic")
+        return CPU;
+      else
+        return "";
+    }
+
+    return llvm::StringSwitch<const char *>(CPUName)
+        .Case("common", "generic")
+        .Case("440", "440")
+        .Case("440fp", "440")
+        .Case("450", "450")
+        .Case("601", "601")
+        .Case("602", "602")
+        .Case("603", "603")
+        .Case("603e", "603e")
+        .Case("603ev", "603ev")
+        .Case("604", "604")
+        .Case("604e", "604e")
+        .Case("620", "620")
+        .Case("630", "pwr3")
+        .Case("G3", "g3")
+        .Case("7400", "7400")
+        .Case("G4", "g4")
+        .Case("7450", "7450")
+        .Case("G4+", "g4+")
+        .Case("750", "750")
+        .Case("970", "970")
+        .Case("G5", "g5")
+        .Case("a2", "a2")
+        .Case("a2q", "a2q")
+        .Case("e500mc", "e500mc")
+        .Case("e5500", "e5500")
+        .Case("power3", "pwr3")
+        .Case("power4", "pwr4")
+        .Case("power5", "pwr5")
+        .Case("power5x", "pwr5x")
+        .Case("power6", "pwr6")
+        .Case("power6x", "pwr6x")
+        .Case("power7", "pwr7")
+        .Case("power8", "pwr8")
+        .Case("power9", "pwr9")
+        .Case("pwr3", "pwr3")
+        .Case("pwr4", "pwr4")
+        .Case("pwr5", "pwr5")
+        .Case("pwr5x", "pwr5x")
+        .Case("pwr6", "pwr6")
+        .Case("pwr6x", "pwr6x")
+        .Case("pwr7", "pwr7")
+        .Case("pwr8", "pwr8")
+        .Case("pwr9", "pwr9")
+        .Case("powerpc", "ppc")
+        .Case("powerpc64", "ppc64")
+        .Case("powerpc64le", "ppc64le")
+        .Default("");
+  }
+
+  return "";
+}
+
+void ppc::getPPCTargetFeatures(const Driver &D, const llvm::Triple &Triple,
+                               const ArgList &Args,
+                               std::vector<StringRef> &Features) {
+  handleTargetFeaturesGroup(Args, Features, options::OPT_m_ppc_Features_Group);
+
+  ppc::FloatABI FloatABI = ppc::getPPCFloatABI(D, Args);
+  if (FloatABI == ppc::FloatABI::Soft)
+    Features.push_back("-hard-float");
+}
+
+ppc::FloatABI ppc::getPPCFloatABI(const Driver &D, const ArgList &Args) {
+  ppc::FloatABI ABI = ppc::FloatABI::Invalid;
+  if (Arg *A =
+          Args.getLastArg(options::OPT_msoft_float, options::OPT_mhard_float,
+                          options::OPT_mfloat_abi_EQ)) {
+    if (A->getOption().matches(options::OPT_msoft_float))
+      ABI = ppc::FloatABI::Soft;
+    else if (A->getOption().matches(options::OPT_mhard_float))
+      ABI = ppc::FloatABI::Hard;
+    else {
+      ABI = llvm::StringSwitch<ppc::FloatABI>(A->getValue())
+                .Case("soft", ppc::FloatABI::Soft)
+                .Case("hard", ppc::FloatABI::Hard)
+                .Default(ppc::FloatABI::Invalid);
+      if (ABI == ppc::FloatABI::Invalid && !StringRef(A->getValue()).empty()) {
+        D.Diag(clang::diag::err_drv_invalid_mfloat_abi) << A->getAsString(Args);
+        ABI = ppc::FloatABI::Hard;
+      }
+    }
+  }
+
+  // If unspecified, choose the default based on the platform.
+  if (ABI == ppc::FloatABI::Invalid) {
+    ABI = ppc::FloatABI::Hard;
+  }
+
+  return ABI;
+}
+
+bool ppc::hasPPCAbiArg(const ArgList &Args, const char *Value) {
+  Arg *A = Args.getLastArg(options::OPT_mabi_EQ);
+  return A && (A->getValue() == StringRef(Value));
+}
diff --git a/lib/Driver/ToolChains/Arch/PPC.h b/lib/Driver/ToolChains/Arch/PPC.h
new file mode 100644
index 000000000000..892eb2c34158
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/PPC.h
@@ -0,0 +1,45 @@
+//===--- PPC.h - PPC-specific Tool Helpers ----------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_PPC_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_PPC_H
+
+#include "clang/Driver/Driver.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Option/Option.h"
+#include <string>
+#include <vector>
+
+namespace clang {
+namespace driver {
+namespace tools {
+namespace ppc {
+
+bool hasPPCAbiArg(const llvm::opt::ArgList &Args, const char *Value);
+
+enum class FloatABI {
+  Invalid,
+  Soft,
+  Hard,
+};
+
+FloatABI getPPCFloatABI(const Driver &D, const llvm::opt::ArgList &Args);
+
+std::string getPPCTargetCPU(const llvm::opt::ArgList &Args);
+
+void getPPCTargetFeatures(const Driver &D, const llvm::Triple &Triple,
+                          const llvm::opt::ArgList &Args,
+                          std::vector<llvm::StringRef> &Features);
+
+} // end namespace ppc
+} // end namespace target
+} // end namespace driver
+} // end namespace clang
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_PPC_H
diff --git a/lib/Driver/ToolChains/Arch/Sparc.cpp b/lib/Driver/ToolChains/Arch/Sparc.cpp
new file mode 100644
index 000000000000..594ec9986d8e
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/Sparc.cpp
@@ -0,0 +1,100 @@
+//===--- Sparc.cpp - Tools Implementations ----------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Sparc.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Options.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Option/ArgList.h"
+
+using namespace clang::driver;
+using namespace clang::driver::tools;
+using namespace clang;
+using namespace llvm::opt;
+
+const char *sparc::getSparcAsmModeForCPU(StringRef Name,
+                                         const llvm::Triple &Triple) {
+  if (Triple.getArch() == llvm::Triple::sparcv9) {
+    return llvm::StringSwitch<const char *>(Name)
+        .Case("niagara", "-Av9b")
+        .Case("niagara2", "-Av9b")
+        .Case("niagara3", "-Av9d")
+        .Case("niagara4", "-Av9d")
+        .Default("-Av9");
+  } else {
+    return llvm::StringSwitch<const char *>(Name)
+        .Case("v8", "-Av8")
+        .Case("supersparc", "-Av8")
+        .Case("sparclite", "-Asparclite")
+        .Case("f934", "-Asparclite")
+        .Case("hypersparc", "-Av8")
+        .Case("sparclite86x", "-Asparclite")
+        .Case("sparclet", "-Asparclet")
+        .Case("tsc701", "-Asparclet")
+        .Case("v9", "-Av8plus")
+        .Case("ultrasparc", "-Av8plus")
+        .Case("ultrasparc3", "-Av8plus")
+        .Case("niagara", "-Av8plusb")
+        .Case("niagara2", "-Av8plusb")
+        .Case("niagara3", "-Av8plusd")
+        .Case("niagara4", "-Av8plusd")
+        .Case("leon2", "-Av8")
+        .Case("at697e", "-Av8")
+        .Case("at697f", "-Av8")
+        .Case("leon3", "-Av8")
+        .Case("ut699", "-Av8")
+        .Case("gr712rc", "-Av8")
+        .Case("leon4", "-Av8")
+        .Case("gr740", "-Av8")
+        .Default("-Av8");
+  }
+}
+
+sparc::FloatABI sparc::getSparcFloatABI(const Driver &D,
+                                        const ArgList &Args) {
+  sparc::FloatABI ABI = sparc::FloatABI::Invalid;
+  if (Arg *A = Args.getLastArg(clang::driver::options::OPT_msoft_float,
+                               options::OPT_mhard_float,
+                               options::OPT_mfloat_abi_EQ)) {
+    if (A->getOption().matches(clang::driver::options::OPT_msoft_float))
+      ABI = sparc::FloatABI::Soft;
+    else if (A->getOption().matches(options::OPT_mhard_float))
+      ABI = sparc::FloatABI::Hard;
+    else {
+      ABI = llvm::StringSwitch<sparc::FloatABI>(A->getValue())
+                .Case("soft", sparc::FloatABI::Soft)
+                .Case("hard", sparc::FloatABI::Hard)
+                .Default(sparc::FloatABI::Invalid);
+      if (ABI == sparc::FloatABI::Invalid &&
+          !StringRef(A->getValue()).empty()) {
+        D.Diag(clang::diag::err_drv_invalid_mfloat_abi) << A->getAsString(Args);
+        ABI = sparc::FloatABI::Hard;
+      }
+    }
+  }
+
+  // If unspecified, choose the default based on the platform.
+  // Only the hard-float ABI on Sparc is standardized, and it is the
+  // default. GCC also supports a nonstandard soft-float ABI mode, also
+  // implemented in LLVM. However as this is not standard we set the default
+  // to be hard-float.
+  if (ABI == sparc::FloatABI::Invalid) {
+    ABI = sparc::FloatABI::Hard;
+  }
+
+  return ABI;
+}
+
+void sparc::getSparcTargetFeatures(const Driver &D, const ArgList &Args,
+                                   std::vector<StringRef> &Features) {
+  sparc::FloatABI FloatABI = sparc::getSparcFloatABI(D, Args);
+  if (FloatABI == sparc::FloatABI::Soft)
+    Features.push_back("+soft-float");
+}
diff --git a/lib/Driver/ToolChains/Arch/Sparc.h b/lib/Driver/ToolChains/Arch/Sparc.h
new file mode 100644
index 000000000000..082b2808a946
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/Sparc.h
@@ -0,0 +1,42 @@
+//===--- Sparc.h - Sparc-specific Tool Helpers ----------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_SPARC_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_SPARC_H
+
+#include "clang/Driver/Driver.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Option/Option.h"
+#include <string>
+#include <vector>
+
+namespace clang {
+namespace driver {
+namespace tools {
+namespace sparc {
+
+enum class FloatABI {
+  Invalid,
+  Soft,
+  Hard,
+};
+
+FloatABI getSparcFloatABI(const Driver &D, const llvm::opt::ArgList &Args);
+
+void getSparcTargetFeatures(const Driver &D, const llvm::opt::ArgList &Args,
+                            std::vector<llvm::StringRef> &Features);
+const char *getSparcAsmModeForCPU(llvm::StringRef Name,
+                                  const llvm::Triple &Triple);
+
+} // end namespace sparc
+} // end namespace target
+} // end namespace driver
+} // end namespace clang
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_SPARC_H
diff --git a/lib/Driver/ToolChains/Arch/SystemZ.cpp b/lib/Driver/ToolChains/Arch/SystemZ.cpp
new file mode 100644
index 000000000000..6ee724d00802
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/SystemZ.cpp
@@ -0,0 +1,41 @@
+//===--- SystemZ.cpp - SystemZ Helpers for Tools ----------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "SystemZ.h"
+#include "clang/Driver/Options.h"
+#include "llvm/Option/ArgList.h"
+
+using namespace clang::driver;
+using namespace clang::driver::tools;
+using namespace clang;
+using namespace llvm::opt;
+
+const char *systemz::getSystemZTargetCPU(const ArgList &Args) {
+  if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_march_EQ))
+    return A->getValue();
+  return "z10";
+}
+
+void systemz::getSystemZTargetFeatures(const ArgList &Args,
+                                       std::vector<llvm::StringRef> &Features) {
+  // -m(no-)htm overrides use of the transactional-execution facility.
+  if (Arg *A = Args.getLastArg(options::OPT_mhtm, options::OPT_mno_htm)) {
+    if (A->getOption().matches(options::OPT_mhtm))
+      Features.push_back("+transactional-execution");
+    else
+      Features.push_back("-transactional-execution");
+  }
+  // -m(no-)vx overrides use of the vector facility.
+  if (Arg *A = Args.getLastArg(options::OPT_mvx, options::OPT_mno_vx)) {
+    if (A->getOption().matches(options::OPT_mvx))
+      Features.push_back("+vector");
+    else
+      Features.push_back("-vector");
+  }
+}
diff --git a/lib/Driver/ToolChains/Arch/SystemZ.h b/lib/Driver/ToolChains/Arch/SystemZ.h
new file mode 100644
index 000000000000..521f8c2aad02
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/SystemZ.h
@@ -0,0 +1,32 @@
+//===--- SystemZ.h - SystemZ-specific Tool Helpers --------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_SYSTEMZ_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_SYSTEMZ_H
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Option/Option.h"
+#include <vector>
+
+namespace clang {
+namespace driver {
+namespace tools {
+namespace systemz {
+
+const char *getSystemZTargetCPU(const llvm::opt::ArgList &Args);
+
+void getSystemZTargetFeatures(const llvm::opt::ArgList &Args,
+                              std::vector<llvm::StringRef> &Features);
+
+} // end namespace systemz
+} // end namespace target
+} // end namespace driver
+} // end namespace clang
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_SYSTEMZ_H
diff --git a/lib/Driver/ToolChains/Arch/X86.cpp b/lib/Driver/ToolChains/Arch/X86.cpp
new file mode 100644
index 000000000000..a85a7f1f6371
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/X86.cpp
@@ -0,0 +1,173 @@
+//===--- X86.cpp - X86 Helpers for Tools ------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "X86.h"
+#include "ToolChains/CommonArgs.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Options.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Option/ArgList.h"
+
+using namespace clang::driver;
+using namespace clang::driver::tools;
+using namespace clang;
+using namespace llvm::opt;
+
+const char *x86::getX86TargetCPU(const ArgList &Args,
+                                 const llvm::Triple &Triple) {
+  if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_march_EQ)) {
+    if (StringRef(A->getValue()) != "native") {
+      if (Triple.isOSDarwin() && Triple.getArchName() == "x86_64h")
+        return "core-avx2";
+
+      return A->getValue();
+    }
+
+    // FIXME: Reject attempts to use -march=native unless the target matches
+    // the host.
+    //
+    // FIXME: We should also incorporate the detected target features for use
+    // with -native.
+    std::string CPU = llvm::sys::getHostCPUName();
+    if (!CPU.empty() && CPU != "generic")
+      return Args.MakeArgString(CPU);
+  }
+
+  if (const Arg *A = Args.getLastArg(options::OPT__SLASH_arch)) {
+    // Mapping built by referring to X86TargetInfo::getDefaultFeatures().
+    StringRef Arch = A->getValue();
+    const char *CPU;
+    if (Triple.getArch() == llvm::Triple::x86) {
+      CPU = llvm::StringSwitch<const char *>(Arch)
+                .Case("IA32", "i386")
+                .Case("SSE", "pentium3")
+                .Case("SSE2", "pentium4")
+                .Case("AVX", "sandybridge")
+                .Case("AVX2", "haswell")
+                .Default(nullptr);
+    } else {
+      CPU = llvm::StringSwitch<const char *>(Arch)
+                .Case("AVX", "sandybridge")
+                .Case("AVX2", "haswell")
+                .Default(nullptr);
+    }
+    if (CPU)
+      return CPU;
+  }
+
+  // Select the default CPU if none was given (or detection failed).
+
+  if (Triple.getArch() != llvm::Triple::x86_64 &&
+      Triple.getArch() != llvm::Triple::x86)
+    return nullptr; // This routine is only handling x86 targets.
+
+  bool Is64Bit = Triple.getArch() == llvm::Triple::x86_64;
+
+  // FIXME: Need target hooks.
+  if (Triple.isOSDarwin()) {
+    if (Triple.getArchName() == "x86_64h")
+      return "core-avx2";
+    // macosx10.12 drops support for all pre-Penryn Macs.
+    // Simulators can still run on 10.11 though, like Xcode.
+    if (Triple.isMacOSX() && !Triple.isOSVersionLT(10, 12))
+      return "penryn";
+    // The oldest x86_64 Macs have core2/Merom; the oldest x86 Macs have Yonah.
+    return Is64Bit ? "core2" : "yonah";
+  }
+
+  // Set up default CPU name for PS4 compilers.
+  if (Triple.isPS4CPU())
+    return "btver2";
+
+  // On Android use targets compatible with gcc
+  if (Triple.isAndroid())
+    return Is64Bit ? "x86-64" : "i686";
+
+  // Everything else goes to x86-64 in 64-bit mode.
+  if (Is64Bit)
+    return "x86-64";
+
+  switch (Triple.getOS()) {
+  case llvm::Triple::FreeBSD:
+  case llvm::Triple::NetBSD:
+  case llvm::Triple::OpenBSD:
+    return "i486";
+  case llvm::Triple::Haiku:
+    return "i586";
+  case llvm::Triple::Bitrig:
+    return "i686";
+  default:
+    // Fallback to p4.
+    return "pentium4";
+  }
+}
+
+void x86::getX86TargetFeatures(const Driver &D, const llvm::Triple &Triple,
+                               const ArgList &Args,
+                               std::vector<StringRef> &Features) {
+  // If -march=native, autodetect the feature list.
+  if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_march_EQ)) {
+    if (StringRef(A->getValue()) == "native") {
+      llvm::StringMap<bool> HostFeatures;
+      if (llvm::sys::getHostCPUFeatures(HostFeatures))
+        for (auto &F : HostFeatures)
+          Features.push_back(
+              Args.MakeArgString((F.second ? "+" : "-") + F.first()));
+    }
+  }
+
+  if (Triple.getArchName() == "x86_64h") {
+    // x86_64h implies quite a few of the more modern subtarget features
+    // for Haswell class CPUs, but not all of them. Opt-out of a few.
+    Features.push_back("-rdrnd");
+    Features.push_back("-aes");
+    Features.push_back("-pclmul");
+    Features.push_back("-rtm");
+    Features.push_back("-fsgsbase");
+  }
+
+  const llvm::Triple::ArchType ArchType = Triple.getArch();
+  // Add features to be compatible with gcc for Android.
+  if (Triple.isAndroid()) {
+    if (ArchType == llvm::Triple::x86_64) {
+      Features.push_back("+sse4.2");
+      Features.push_back("+popcnt");
+    } else
+      Features.push_back("+ssse3");
+  }
+
+  // Set features according to the -arch flag on MSVC.
+  if (Arg *A = Args.getLastArg(options::OPT__SLASH_arch)) {
+    StringRef Arch = A->getValue();
+    bool ArchUsed = false;
+    // First, look for flags that are shared in x86 and x86-64.
+    if (ArchType == llvm::Triple::x86_64 || ArchType == llvm::Triple::x86) {
+      if (Arch == "AVX" || Arch == "AVX2") {
+        ArchUsed = true;
+        Features.push_back(Args.MakeArgString("+" + Arch.lower()));
+      }
+    }
+    // Then, look for x86-specific flags.
+    if (ArchType == llvm::Triple::x86) {
+      if (Arch == "IA32") {
+        ArchUsed = true;
+      } else if (Arch == "SSE" || Arch == "SSE2") {
+        ArchUsed = true;
+        Features.push_back(Args.MakeArgString("+" + Arch.lower()));
+      }
+    }
+    if (!ArchUsed)
+      D.Diag(clang::diag::warn_drv_unused_argument) << A->getAsString(Args);
+  }
+
+  // Now add any that the user explicitly requested on the command line,
+  // which may override the defaults.
+  handleTargetFeaturesGroup(Args, Features, options::OPT_m_x86_Features_Group);
+}
diff --git a/lib/Driver/ToolChains/Arch/X86.h b/lib/Driver/ToolChains/Arch/X86.h
new file mode 100644
index 000000000000..20bf27a2b6bc
--- /dev/null
+++ b/lib/Driver/ToolChains/Arch/X86.h
@@ -0,0 +1,37 @@
+//===--- X86.h - X86-specific Tool Helpers ----------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_X86_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_X86_H
+
+#include "clang/Driver/Driver.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/Option/Option.h"
+#include <string>
+#include <vector>
+
+namespace clang {
+namespace driver {
+namespace tools {
+namespace x86 {
+
+const char *getX86TargetCPU(const llvm::opt::ArgList &Args,
+                            const llvm::Triple &Triple);
+
+void getX86TargetFeatures(const Driver &D, const llvm::Triple &Triple,
+                          const llvm::opt::ArgList &Args,
+                          std::vector<llvm::StringRef> &Features);
+
+} // end namespace x86
+} // end namespace target
+} // end namespace driver
+} // end namespace clang
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_ARCH_X86_H
diff --git a/lib/Driver/ToolChains/Bitrig.cpp b/lib/Driver/ToolChains/Bitrig.cpp
new file mode 100644
index 000000000000..d8f541dfbaf1
--- /dev/null
+++ b/lib/Driver/ToolChains/Bitrig.cpp
@@ -0,0 +1,190 @@
+//===--- Bitrig.cpp - Bitrig ToolChain Implementations ----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Bitrig.h"
+#include "CommonArgs.h"
+#include "clang/Driver/Compilation.h"
+#include "clang/Driver/Options.h"
+#include "llvm/Option/ArgList.h"
+
+using namespace clang::driver;
+using namespace clang::driver::toolchains;
+using namespace clang::driver::tools;
+using namespace clang;
+using namespace llvm::opt;
+
+void bitrig::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
+                                     const InputInfo &Output,
+                                     const InputInfoList &Inputs,
+                                     const ArgList &Args,
+                                     const char *LinkingOutput) const {
+  claimNoWarnArgs(Args);
+  ArgStringList CmdArgs;
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA, options::OPT_Xassembler);
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  for (const auto &II : Inputs)
+    CmdArgs.push_back(II.getFilename());
+
+  const char *Exec = Args.MakeArgString(getToolChain().GetProgramPath("as"));
+  C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
+}
+
+void bitrig::Linker::ConstructJob(Compilation &C, const JobAction &JA,
+                                  const InputInfo &Output,
+                                  const InputInfoList &Inputs,
+                                  const ArgList &Args,
+                                  const char *LinkingOutput) const {
+  const Driver &D = getToolChain().getDriver();
+  ArgStringList CmdArgs;
+
+  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_shared)) {
+    CmdArgs.push_back("-e");
+    CmdArgs.push_back("__start");
+  }
+
+  if (Args.hasArg(options::OPT_static)) {
+    CmdArgs.push_back("-Bstatic");
+  } else {
+    if (Args.hasArg(options::OPT_rdynamic))
+      CmdArgs.push_back("-export-dynamic");
+    CmdArgs.push_back("--eh-frame-hdr");
+    CmdArgs.push_back("-Bdynamic");
+    if (Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back("-shared");
+    } else {
+      CmdArgs.push_back("-dynamic-linker");
+      CmdArgs.push_back("/usr/libexec/ld.so");
+    }
+  }
+
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Invalid output.");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared)) {
+      if (Args.hasArg(options::OPT_pg))
+        CmdArgs.push_back(
+            Args.MakeArgString(getToolChain().GetFilePath("gcrt0.o")));
+      else
+        CmdArgs.push_back(
+            Args.MakeArgString(getToolChain().GetFilePath("crt0.o")));
+      CmdArgs.push_back(
+          Args.MakeArgString(getToolChain().GetFilePath("crtbegin.o")));
+    } else {
+      CmdArgs.push_back(
+          Args.MakeArgString(getToolChain().GetFilePath("crtbeginS.o")));
+    }
+  }
+
+  Args.AddAllArgs(CmdArgs,
+                  {options::OPT_L, options::OPT_T_Group, options::OPT_e});
+
+  AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs, JA);
+
+  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
+    if (D.CCCIsCXX()) {
+      getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
+      if (Args.hasArg(options::OPT_pg))
+        CmdArgs.push_back("-lm_p");
+      else
+        CmdArgs.push_back("-lm");
+    }
+
+    if (Args.hasArg(options::OPT_pthread)) {
+      if (!Args.hasArg(options::OPT_shared) && Args.hasArg(options::OPT_pg))
+        CmdArgs.push_back("-lpthread_p");
+      else
+        CmdArgs.push_back("-lpthread");
+    }
+
+    if (!Args.hasArg(options::OPT_shared)) {
+      if (Args.hasArg(options::OPT_pg))
+        CmdArgs.push_back("-lc_p");
+      else
+        CmdArgs.push_back("-lc");
+    }
+
+    StringRef MyArch;
+    switch (getToolChain().getArch()) {
+    case llvm::Triple::arm:
+      MyArch = "arm";
+      break;
+    case llvm::Triple::x86:
+      MyArch = "i386";
+      break;
+    case llvm::Triple::x86_64:
+      MyArch = "amd64";
+      break;
+    default:
+      llvm_unreachable("Unsupported architecture");
+    }
+    CmdArgs.push_back(Args.MakeArgString("-lclang_rt." + MyArch));
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared))
+      CmdArgs.push_back(
+          Args.MakeArgString(getToolChain().GetFilePath("crtend.o")));
+    else
+      CmdArgs.push_back(
+          Args.MakeArgString(getToolChain().GetFilePath("crtendS.o")));
+  }
+
+  const char *Exec = Args.MakeArgString(getToolChain().GetLinkerPath());
+  C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
+}
+
+/// Bitrig - Bitrig tool chain which can call as(1) and ld(1) directly.
+
+Bitrig::Bitrig(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
+    : Generic_ELF(D, Triple, Args) {
+  getFilePaths().push_back(getDriver().Dir + "/../lib");
+  getFilePaths().push_back("/usr/lib");
+}
+
+Tool *Bitrig::buildAssembler() const {
+  return new tools::bitrig::Assembler(*this);
+}
+
+Tool *Bitrig::buildLinker() const { return new tools::bitrig::Linker(*this); }
+
+ToolChain::CXXStdlibType Bitrig::GetDefaultCXXStdlibType() const {
+  return ToolChain::CST_Libcxx;
+}
+
+void Bitrig::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
+                                      llvm::opt::ArgStringList &CC1Args) const {
+  std::string Triple = getTriple().str();
+  if (StringRef(Triple).startswith("amd64"))
+    Triple = "x86_64" + Triple.substr(5);
+  addLibStdCXXIncludePaths(getDriver().SysRoot, "/usr/include/c++/stdc++",
+                           Triple, "", "", "", DriverArgs, CC1Args);
+}
+
+void Bitrig::AddCXXStdlibLibArgs(const ArgList &Args,
+                                 ArgStringList &CmdArgs) const {
+  switch (GetCXXStdlibType(Args)) {
+  case ToolChain::CST_Libcxx:
+    CmdArgs.push_back("-lc++");
+    CmdArgs.push_back("-lc++abi");
+    CmdArgs.push_back("-lpthread");
+    break;
+  case ToolChain::CST_Libstdcxx:
+    CmdArgs.push_back("-lstdc++");
+    break;
+  }
+}
diff --git a/lib/Driver/ToolChains/Bitrig.h b/lib/Driver/ToolChains/Bitrig.h
new file mode 100644
index 000000000000..6edb2e8c7e8c
--- /dev/null
+++ b/lib/Driver/ToolChains/Bitrig.h
@@ -0,0 +1,79 @@
+//===--- Bitrig.h - Bitrig ToolChain Implementations ------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_BITRIG_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_BITRIG_H
+
+#include "Gnu.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/ToolChain.h"
+
+namespace clang {
+namespace driver {
+namespace tools {
+/// bitrig -- Directly call GNU Binutils assembler and linker
+namespace bitrig {
+class LLVM_LIBRARY_VISIBILITY Assembler : public GnuTool {
+public:
+  Assembler(const ToolChain &TC)
+      : GnuTool("bitrig::Assembler", "assembler", TC) {}
+
+  bool hasIntegratedCPP() const override { return false; }
+
+  void ConstructJob(Compilation &C, const JobAction &JA,
+                    const InputInfo &Output, const InputInfoList &Inputs,
+                    const llvm::opt::ArgList &TCArgs,
+                    const char *LinkingOutput) const override;
+};
+
+class LLVM_LIBRARY_VISIBILITY Linker : public GnuTool {
+public:
+  Linker(const ToolChain &TC) : GnuTool("bitrig::Linker", "linker", TC) {}
+
+  bool hasIntegratedCPP() const override { return false; }
+  bool isLinkJob() const override { return true; }
+
+  void ConstructJob(Compilation &C, const JobAction &JA,
+                    const InputInfo &Output, const InputInfoList &Inputs,
+                    const llvm::opt::ArgList &TCArgs,
+                    const char *LinkingOutput) const override;
+};
+} // end namespace bitrig
+} // end namespace tools
+
+namespace toolchains {
+
+class LLVM_LIBRARY_VISIBILITY Bitrig : public Generic_ELF {
+public:
+  Bitrig(const Driver &D, const llvm::Triple &Triple,
+         const llvm::opt::ArgList &Args);
+
+  bool IsMathErrnoDefault() const override { return false; }
+  bool IsObjCNonFragileABIDefault() const override { return true; }
+
+  CXXStdlibType GetDefaultCXXStdlibType() const override;
+  void addLibStdCxxIncludePaths(
+      const llvm::opt::ArgList &DriverArgs,
+      llvm::opt::ArgStringList &CC1Args) const override;
+  void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
+                           llvm::opt::ArgStringList &CmdArgs) const override;
+  unsigned GetDefaultStackProtectorLevel(bool KernelOrKext) const override {
+    return 1;
+  }
+
+protected:
+  Tool *buildAssembler() const override;
+  Tool *buildLinker() const override;
+};
+
+} // end namespace toolchains
+} // end namespace driver
+} // end namespace clang
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_BITRIG_H
diff --git a/lib/Driver/ToolChains/Clang.cpp b/lib/Driver/ToolChains/Clang.cpp
new file mode 100644
index 000000000000..f8eeeb4eef69
--- /dev/null
+++ b/lib/Driver/ToolChains/Clang.cpp
@@ -0,0 +1,5160 @@
+//===--- LLVM.cpp - Clang+LLVM ToolChain Implementations --------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Clang.h"
+#include "Arch/AArch64.h"
+#include "Arch/ARM.h"
+#include "Arch/Mips.h"
+#include "Arch/PPC.h"
+#include "Arch/Sparc.h"
+#include "Arch/SystemZ.h"
+#include "Arch/X86.h"
+#include "CommonArgs.h"
+#include "Hexagon.h"
+#include "InputInfo.h"
+#include "PS4CPU.h"
+#include "clang/Basic/CharInfo.h"
+#include "clang/Basic/LangOptions.h"
+#include "clang/Basic/ObjCRuntime.h"
+#include "clang/Basic/Version.h"
+#include "clang/Config/config.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Options.h"
+#include "clang/Driver/SanitizerArgs.h"
+#include "clang/Driver/XRayArgs.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Option/ArgList.h"
+#include "llvm/Support/CodeGen.h"
+#include "llvm/Support/Compression.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/Process.h"
+#include "llvm/Support/YAMLParser.h"
+
+#ifdef LLVM_ON_UNIX
+#include <unistd.h> // For getuid().
+#endif
+
+using namespace clang::driver;
+using namespace clang::driver::tools;
+using namespace clang;
+using namespace llvm::opt;
+
+static void CheckPreprocessingOptions(const Driver &D, const ArgList &Args) {
+  if (Arg *A =
+          Args.getLastArg(clang::driver::options::OPT_C, options::OPT_CC)) {
+    if (!Args.hasArg(options::OPT_E) && !Args.hasArg(options::OPT__SLASH_P) &&
+        !Args.hasArg(options::OPT__SLASH_EP) && !D.CCCIsCPP()) {
+      D.Diag(clang::diag::err_drv_argument_only_allowed_with)
+          << A->getBaseArg().getAsString(Args)
+          << (D.IsCLMode() ? "/E, /P or /EP" : "-E");
+    }
+  }
+}
+
+static void CheckCodeGenerationOptions(const Driver &D, const ArgList &Args) {
+  // In gcc, only ARM checks this, but it seems reasonable to check universally.
+  if (Args.hasArg(options::OPT_static))
+    if (const Arg *A =
+            Args.getLastArg(options::OPT_dynamic, options::OPT_mdynamic_no_pic))
+      D.Diag(diag::err_drv_argument_not_allowed_with) << A->getAsString(Args)
+                                                      << "-static";
+}
+
+// Add backslashes to escape spaces and other backslashes.
+// This is used for the space-separated argument list specified with
+// the -dwarf-debug-flags option.
+static void EscapeSpacesAndBackslashes(const char *Arg,
+                                       SmallVectorImpl<char> &Res) {
+  for (; *Arg; ++Arg) {
+    switch (*Arg) {
+    default:
+      break;
+    case ' ':
+    case '\\':
+      Res.push_back('\\');
+      break;
+    }
+    Res.push_back(*Arg);
+  }
+}
+
+// Quote target names for inclusion in GNU Make dependency files.
+// Only the characters '$', '#', ' ', '\t' are quoted.
+static void QuoteTarget(StringRef Target, SmallVectorImpl<char> &Res) {
+  for (unsigned i = 0, e = Target.size(); i != e; ++i) {
+    switch (Target[i]) {
+    case ' ':
+    case '\t':
+      // Escape the preceding backslashes
+      for (int j = i - 1; j >= 0 && Target[j] == '\\'; --j)
+        Res.push_back('\\');
+
+      // Escape the space/tab
+      Res.push_back('\\');
+      break;
+    case '$':
+      Res.push_back('$');
+      break;
+    case '#':
+      Res.push_back('\\');
+      break;
+    default:
+      break;
+    }
+
+    Res.push_back(Target[i]);
+  }
+}
+
+/// Apply \a Work on the current tool chain \a RegularToolChain and any other
+/// offloading tool chain that is associated with the current action \a JA.
+static void
+forAllAssociatedToolChains(Compilation &C, const JobAction &JA,
+                           const ToolChain &RegularToolChain,
+                           llvm::function_ref<void(const ToolChain &)> Work) {
+  // Apply Work on the current/regular tool chain.
+  Work(RegularToolChain);
+
+  // Apply Work on all the offloading tool chains associated with the current
+  // action.
+  if (JA.isHostOffloading(Action::OFK_Cuda))
+    Work(*C.getSingleOffloadToolChain<Action::OFK_Cuda>());
+  else if (JA.isDeviceOffloading(Action::OFK_Cuda))
+    Work(*C.getSingleOffloadToolChain<Action::OFK_Host>());
+
+  //
+  // TODO: Add support for other offloading programming models here.
+  //
+}
+
+/// This is a helper function for validating the optional refinement step
+/// parameter in reciprocal argument strings. Return false if there is an error
+/// parsing the refinement step. Otherwise, return true and set the Position
+/// of the refinement step in the input string.
+static bool getRefinementStep(StringRef In, const Driver &D,
+                              const Arg &A, size_t &Position) {
+  const char RefinementStepToken = ':';
+  Position = In.find(RefinementStepToken);
+  if (Position != StringRef::npos) {
+    StringRef Option = A.getOption().getName();
+    StringRef RefStep = In.substr(Position + 1);
+    // Allow exactly one numeric character for the additional refinement
+    // step parameter. This is reasonable for all currently-supported
+    // operations and architectures because we would expect that a larger value
+    // of refinement steps would cause the estimate "optimization" to
+    // under-perform the native operation. Also, if the estimate does not
+    // converge quickly, it probably will not ever converge, so further
+    // refinement steps will not produce a better answer.
+    if (RefStep.size() != 1) {
+      D.Diag(diag::err_drv_invalid_value) << Option << RefStep;
+      return false;
+    }
+    char RefStepChar = RefStep[0];
+    if (RefStepChar < '0' || RefStepChar > '9') {
+      D.Diag(diag::err_drv_invalid_value) << Option << RefStep;
+      return false;
+    }
+  }
+  return true;
+}
+
+/// The -mrecip flag requires processing of many optional parameters.
+static void ParseMRecip(const Driver &D, const ArgList &Args,
+                        ArgStringList &OutStrings) {
+  StringRef DisabledPrefixIn = "!";
+  StringRef DisabledPrefixOut = "!";
+  StringRef EnabledPrefixOut = "";
+  StringRef Out = "-mrecip=";
+
+  Arg *A = Args.getLastArg(options::OPT_mrecip, options::OPT_mrecip_EQ);
+  if (!A)
+    return;
+
+  unsigned NumOptions = A->getNumValues();
+  if (NumOptions == 0) {
+    // No option is the same as "all".
+    OutStrings.push_back(Args.MakeArgString(Out + "all"));
+    return;
+  }
+
+  // Pass through "all", "none", or "default" with an optional refinement step.
+  if (NumOptions == 1) {
+    StringRef Val = A->getValue(0);
+    size_t RefStepLoc;
+    if (!getRefinementStep(Val, D, *A, RefStepLoc))
+      return;
+    StringRef ValBase = Val.slice(0, RefStepLoc);
+    if (ValBase == "all" || ValBase == "none" || ValBase == "default") {
+      OutStrings.push_back(Args.MakeArgString(Out + Val));
+      return;
+    }
+  }
+
+  // Each reciprocal type may be enabled or disabled individually.
+  // Check each input value for validity, concatenate them all back together,
+  // and pass through.
+
+  llvm::StringMap<bool> OptionStrings;
+  OptionStrings.insert(std::make_pair("divd", false));
+  OptionStrings.insert(std::make_pair("divf", false));
+  OptionStrings.insert(std::make_pair("vec-divd", false));
+  OptionStrings.insert(std::make_pair("vec-divf", false));
+  OptionStrings.insert(std::make_pair("sqrtd", false));
+  OptionStrings.insert(std::make_pair("sqrtf", false));
+  OptionStrings.insert(std::make_pair("vec-sqrtd", false));
+  OptionStrings.insert(std::make_pair("vec-sqrtf", false));
+
+  for (unsigned i = 0; i != NumOptions; ++i) {
+    StringRef Val = A->getValue(i);
+
+    bool IsDisabled = Val.startswith(DisabledPrefixIn);
+    // Ignore the disablement token for string matching.
+    if (IsDisabled)
+      Val = Val.substr(1);
+
+    size_t RefStep;
+    if (!getRefinementStep(Val, D, *A, RefStep))
+      return;
+
+    StringRef ValBase = Val.slice(0, RefStep);
+    llvm::StringMap<bool>::iterator OptionIter = OptionStrings.find(ValBase);
+    if (OptionIter == OptionStrings.end()) {
+      // Try again specifying float suffix.
+      OptionIter = OptionStrings.find(ValBase.str() + 'f');
+      if (OptionIter == OptionStrings.end()) {
+        // The input name did not match any known option string.
+        D.Diag(diag::err_drv_unknown_argument) << Val;
+        return;
+      }
+      // The option was specified without a float or double suffix.
+      // Make sure that the double entry was not already specified.
+      // The float entry will be checked below.
+      if (OptionStrings[ValBase.str() + 'd']) {
+        D.Diag(diag::err_drv_invalid_value) << A->getOption().getName() << Val;
+        return;
+      }
+    }
+
+    if (OptionIter->second == true) {
+      // Duplicate option specified.
+      D.Diag(diag::err_drv_invalid_value) << A->getOption().getName() << Val;
+      return;
+    }
+
+    // Mark the matched option as found. Do not allow duplicate specifiers.
+    OptionIter->second = true;
+
+    // If the precision was not specified, also mark the double entry as found.
+    if (ValBase.back() != 'f' && ValBase.back() != 'd')
+      OptionStrings[ValBase.str() + 'd'] = true;
+
+    // Build the output string.
+    StringRef Prefix = IsDisabled ? DisabledPrefixOut : EnabledPrefixOut;
+    Out = Args.MakeArgString(Out + Prefix + Val);
+    if (i != NumOptions - 1)
+      Out = Args.MakeArgString(Out + ",");
+  }
+
+  OutStrings.push_back(Args.MakeArgString(Out));
+}
+
+static void getHexagonTargetFeatures(const ArgList &Args,
+                                     std::vector<StringRef> &Features) {
+  handleTargetFeaturesGroup(Args, Features,
+                            options::OPT_m_hexagon_Features_Group);
+
+  bool UseLongCalls = false;
+  if (Arg *A = Args.getLastArg(options::OPT_mlong_calls,
+                               options::OPT_mno_long_calls)) {
+    if (A->getOption().matches(options::OPT_mlong_calls))
+      UseLongCalls = true;
+  }
+
+  Features.push_back(UseLongCalls ? "+long-calls" : "-long-calls");
+}
+
+static void getWebAssemblyTargetFeatures(const ArgList &Args,
+                                         std::vector<StringRef> &Features) {
+  handleTargetFeaturesGroup(Args, Features, options::OPT_m_wasm_Features_Group);
+}
+
+static void getAMDGPUTargetFeatures(const Driver &D, const ArgList &Args,
+                                    std::vector<StringRef> &Features) {
+  if (const Arg *dAbi = Args.getLastArg(options::OPT_mamdgpu_debugger_abi)) {
+    StringRef value = dAbi->getValue();
+    if (value == "1.0") {
+      Features.push_back("+amdgpu-debugger-insert-nops");
+      Features.push_back("+amdgpu-debugger-reserve-regs");
+      Features.push_back("+amdgpu-debugger-emit-prologue");
+    } else {
+      D.Diag(diag::err_drv_clang_unsupported) << dAbi->getAsString(Args);
+    }
+  }
+
+  handleTargetFeaturesGroup(
+    Args, Features, options::OPT_m_amdgpu_Features_Group);
+}
+
+static void getTargetFeatures(const ToolChain &TC, const llvm::Triple &Triple,
+                              const ArgList &Args, ArgStringList &CmdArgs,
+                              bool ForAS) {
+  const Driver &D = TC.getDriver();
+  std::vector<StringRef> Features;
+  switch (Triple.getArch()) {
+  default:
+    break;
+  case llvm::Triple::mips:
+  case llvm::Triple::mipsel:
+  case llvm::Triple::mips64:
+  case llvm::Triple::mips64el:
+    mips::getMIPSTargetFeatures(D, Triple, Args, Features);
+    break;
+
+  case llvm::Triple::arm:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumb:
+  case llvm::Triple::thumbeb:
+    arm::getARMTargetFeatures(TC, Triple, Args, CmdArgs, Features, ForAS);
+    break;
+
+  case llvm::Triple::ppc:
+  case llvm::Triple::ppc64:
+  case llvm::Triple::ppc64le:
+    ppc::getPPCTargetFeatures(D, Triple, Args, Features);
+    break;
+  case llvm::Triple::systemz:
+    systemz::getSystemZTargetFeatures(Args, Features);
+    break;
+  case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_be:
+    aarch64::getAArch64TargetFeatures(D, Args, Features);
+    break;
+  case llvm::Triple::x86:
+  case llvm::Triple::x86_64:
+    x86::getX86TargetFeatures(D, Triple, Args, Features);
+    break;
+  case llvm::Triple::hexagon:
+    getHexagonTargetFeatures(Args, Features);
+    break;
+  case llvm::Triple::wasm32:
+  case llvm::Triple::wasm64:
+    getWebAssemblyTargetFeatures(Args, Features);
+    break;
+  case llvm::Triple::sparc:
+  case llvm::Triple::sparcel:
+  case llvm::Triple::sparcv9:
+    sparc::getSparcTargetFeatures(D, Args, Features);
+    break;
+  case llvm::Triple::r600:
+  case llvm::Triple::amdgcn:
+    getAMDGPUTargetFeatures(D, Args, Features);
+    break;
+  }
+
+  // Find the last of each feature.
+  llvm::StringMap<unsigned> LastOpt;
+  for (unsigned I = 0, N = Features.size(); I < N; ++I) {
+    StringRef Name = Features[I];
+    assert(Name[0] == '-' || Name[0] == '+');
+    LastOpt[Name.drop_front(1)] = I;
+  }
+
+  for (unsigned I = 0, N = Features.size(); I < N; ++I) {
+    // If this feature was overridden, ignore it.
+    StringRef Name = Features[I];
+    llvm::StringMap<unsigned>::iterator LastI = LastOpt.find(Name.drop_front(1));
+    assert(LastI != LastOpt.end());
+    unsigned Last = LastI->second;
+    if (Last != I)
+      continue;
+
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back(Name.data());
+  }
+}
+
+static bool
+shouldUseExceptionTablesForObjCExceptions(const ObjCRuntime &runtime,
+                                          const llvm::Triple &Triple) {
+  // We use the zero-cost exception tables for Objective-C if the non-fragile
+  // ABI is enabled or when compiling for x86_64 and ARM on Snow Leopard and
+  // later.
+  if (runtime.isNonFragile())
+    return true;
+
+  if (!Triple.isMacOSX())
+    return false;
+
+  return (!Triple.isMacOSXVersionLT(10, 5) &&
+          (Triple.getArch() == llvm::Triple::x86_64 ||
+           Triple.getArch() == llvm::Triple::arm));
+}
+
+/// Adds exception related arguments to the driver command arguments. There's a
+/// master flag, -fexceptions and also language specific flags to enable/disable
+/// C++ and Objective-C exceptions. This makes it possible to for example
+/// disable C++ exceptions but enable Objective-C exceptions.
+static void addExceptionArgs(const ArgList &Args, types::ID InputType,
+                             const ToolChain &TC, bool KernelOrKext,
+                             const ObjCRuntime &objcRuntime,
+                             ArgStringList &CmdArgs) {
+  const Driver &D = TC.getDriver();
+  const llvm::Triple &Triple = TC.getTriple();
+
+  if (KernelOrKext) {
+    // -mkernel and -fapple-kext imply no exceptions, so claim exception related
+    // arguments now to avoid warnings about unused arguments.
+    Args.ClaimAllArgs(options::OPT_fexceptions);
+    Args.ClaimAllArgs(options::OPT_fno_exceptions);
+    Args.ClaimAllArgs(options::OPT_fobjc_exceptions);
+    Args.ClaimAllArgs(options::OPT_fno_objc_exceptions);
+    Args.ClaimAllArgs(options::OPT_fcxx_exceptions);
+    Args.ClaimAllArgs(options::OPT_fno_cxx_exceptions);
+    return;
+  }
+
+  // See if the user explicitly enabled exceptions.
+  bool EH = Args.hasFlag(options::OPT_fexceptions, options::OPT_fno_exceptions,
+                         false);
+
+  // Obj-C exceptions are enabled by default, regardless of -fexceptions. This
+  // is not necessarily sensible, but follows GCC.
+  if (types::isObjC(InputType) &&
+      Args.hasFlag(options::OPT_fobjc_exceptions,
+                   options::OPT_fno_objc_exceptions, true)) {
+    CmdArgs.push_back("-fobjc-exceptions");
+
+    EH |= shouldUseExceptionTablesForObjCExceptions(objcRuntime, Triple);
+  }
+
+  if (types::isCXX(InputType)) {
+    // Disable C++ EH by default on XCore and PS4.
+    bool CXXExceptionsEnabled =
+        Triple.getArch() != llvm::Triple::xcore && !Triple.isPS4CPU();
+    Arg *ExceptionArg = Args.getLastArg(
+        options::OPT_fcxx_exceptions, options::OPT_fno_cxx_exceptions,
+        options::OPT_fexceptions, options::OPT_fno_exceptions);
+    if (ExceptionArg)
+      CXXExceptionsEnabled =
+          ExceptionArg->getOption().matches(options::OPT_fcxx_exceptions) ||
+          ExceptionArg->getOption().matches(options::OPT_fexceptions);
+
+    if (CXXExceptionsEnabled) {
+      if (Triple.isPS4CPU()) {
+        ToolChain::RTTIMode RTTIMode = TC.getRTTIMode();
+        assert(ExceptionArg &&
+               "On the PS4 exceptions should only be enabled if passing "
+               "an argument");
+        if (RTTIMode == ToolChain::RM_DisabledExplicitly) {
+          const Arg *RTTIArg = TC.getRTTIArg();
+          assert(RTTIArg && "RTTI disabled explicitly but no RTTIArg!");
+          D.Diag(diag::err_drv_argument_not_allowed_with)
+              << RTTIArg->getAsString(Args) << ExceptionArg->getAsString(Args);
+        } else if (RTTIMode == ToolChain::RM_EnabledImplicitly)
+          D.Diag(diag::warn_drv_enabling_rtti_with_exceptions);
+      } else
+        assert(TC.getRTTIMode() != ToolChain::RM_DisabledImplicitly);
+
+      CmdArgs.push_back("-fcxx-exceptions");
+
+      EH = true;
+    }
+  }
+
+  if (EH)
+    CmdArgs.push_back("-fexceptions");
+}
+
+static bool ShouldDisableAutolink(const ArgList &Args, const ToolChain &TC) {
+  bool Default = true;
+  if (TC.getTriple().isOSDarwin()) {
+    // The native darwin assembler doesn't support the linker_option directives,
+    // so we disable them if we think the .s file will be passed to it.
+    Default = TC.useIntegratedAs();
+  }
+  return !Args.hasFlag(options::OPT_fautolink, options::OPT_fno_autolink,
+                       Default);
+}
+
+static bool ShouldDisableDwarfDirectory(const ArgList &Args,
+                                        const ToolChain &TC) {
+  bool UseDwarfDirectory =
+      Args.hasFlag(options::OPT_fdwarf_directory_asm,
+                   options::OPT_fno_dwarf_directory_asm, TC.useIntegratedAs());
+  return !UseDwarfDirectory;
+}
+
+// Convert an arg of the form "-gN" or "-ggdbN" or one of their aliases
+// to the corresponding DebugInfoKind.
+static codegenoptions::DebugInfoKind DebugLevelToInfoKind(const Arg &A) {
+  assert(A.getOption().matches(options::OPT_gN_Group) &&
+         "Not a -g option that specifies a debug-info level");
+  if (A.getOption().matches(options::OPT_g0) ||
+      A.getOption().matches(options::OPT_ggdb0))
+    return codegenoptions::NoDebugInfo;
+  if (A.getOption().matches(options::OPT_gline_tables_only) ||
+      A.getOption().matches(options::OPT_ggdb1))
+    return codegenoptions::DebugLineTablesOnly;
+  return codegenoptions::LimitedDebugInfo;
+}
+
+static bool mustUseNonLeafFramePointerForTarget(const llvm::Triple &Triple) {
+  switch (Triple.getArch()){
+  default:
+    return false;
+  case llvm::Triple::arm:
+  case llvm::Triple::thumb:
+    // ARM Darwin targets require a frame pointer to be always present to aid
+    // offline debugging via backtraces.
+    return Triple.isOSDarwin();
+  }
+}
+
+static bool useFramePointerForTargetByDefault(const ArgList &Args,
+                                              const llvm::Triple &Triple) {
+  switch (Triple.getArch()) {
+  case llvm::Triple::xcore:
+  case llvm::Triple::wasm32:
+  case llvm::Triple::wasm64:
+    // XCore never wants frame pointers, regardless of OS.
+    // WebAssembly never wants frame pointers.
+    return false;
+  default:
+    break;
+  }
+
+  if (Triple.isOSLinux() || Triple.getOS() == llvm::Triple::CloudABI) {
+    switch (Triple.getArch()) {
+    // Don't use a frame pointer on linux if optimizing for certain targets.
+    case llvm::Triple::mips64:
+    case llvm::Triple::mips64el:
+    case llvm::Triple::mips:
+    case llvm::Triple::mipsel:
+    case llvm::Triple::ppc:
+    case llvm::Triple::ppc64:
+    case llvm::Triple::ppc64le:
+    case llvm::Triple::systemz:
+    case llvm::Triple::x86:
+    case llvm::Triple::x86_64:
+      return !areOptimizationsEnabled(Args);
+    default:
+      return true;
+    }
+  }
+
+  if (Triple.isOSWindows()) {
+    switch (Triple.getArch()) {
+    case llvm::Triple::x86:
+      return !areOptimizationsEnabled(Args);
+    case llvm::Triple::x86_64:
+      return Triple.isOSBinFormatMachO();
+    case llvm::Triple::arm:
+    case llvm::Triple::thumb:
+      // Windows on ARM builds with FPO disabled to aid fast stack walking
+      return true;
+    default:
+      // All other supported Windows ISAs use xdata unwind information, so frame
+      // pointers are not generally useful.
+      return false;
+    }
+  }
+
+  return true;
+}
+
+static bool shouldUseFramePointer(const ArgList &Args,
+                                  const llvm::Triple &Triple) {
+  if (Arg *A = Args.getLastArg(options::OPT_fno_omit_frame_pointer,
+                               options::OPT_fomit_frame_pointer))
+    return A->getOption().matches(options::OPT_fno_omit_frame_pointer) ||
+           mustUseNonLeafFramePointerForTarget(Triple);
+
+  if (Args.hasArg(options::OPT_pg))
+    return true;
+
+  return useFramePointerForTargetByDefault(Args, Triple);
+}
+
+static bool shouldUseLeafFramePointer(const ArgList &Args,
+                                      const llvm::Triple &Triple) {
+  if (Arg *A = Args.getLastArg(options::OPT_mno_omit_leaf_frame_pointer,
+                               options::OPT_momit_leaf_frame_pointer))
+    return A->getOption().matches(options::OPT_mno_omit_leaf_frame_pointer);
+
+  if (Args.hasArg(options::OPT_pg))
+    return true;
+
+  if (Triple.isPS4CPU())
+    return false;
+
+  return useFramePointerForTargetByDefault(Args, Triple);
+}
+
+/// Add a CC1 option to specify the debug compilation directory.
+static void addDebugCompDirArg(const ArgList &Args, ArgStringList &CmdArgs) {
+  SmallString<128> cwd;
+  if (!llvm::sys::fs::current_path(cwd)) {
+    CmdArgs.push_back("-fdebug-compilation-dir");
+    CmdArgs.push_back(Args.MakeArgString(cwd));
+  }
+}
+
+/// \brief Vectorize at all optimization levels greater than 1 except for -Oz.
+/// For -Oz the loop vectorizer is disable, while the slp vectorizer is enabled.
+static bool shouldEnableVectorizerAtOLevel(const ArgList &Args, bool isSlpVec) {
+  if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
+    if (A->getOption().matches(options::OPT_O4) ||
+        A->getOption().matches(options::OPT_Ofast))
+      return true;
+
+    if (A->getOption().matches(options::OPT_O0))
+      return false;
+
+    assert(A->getOption().matches(options::OPT_O) && "Must have a -O flag");
+
+    // Vectorize -Os.
+    StringRef S(A->getValue());
+    if (S == "s")
+      return true;
+
+    // Don't vectorize -Oz, unless it's the slp vectorizer.
+    if (S == "z")
+      return isSlpVec;
+
+    unsigned OptLevel = 0;
+    if (S.getAsInteger(10, OptLevel))
+      return false;
+
+    return OptLevel > 1;
+  }
+
+  return false;
+}
+
+/// Add -x lang to \p CmdArgs for \p Input.
+static void addDashXForInput(const ArgList &Args, const InputInfo &Input,
+                             ArgStringList &CmdArgs) {
+  // When using -verify-pch, we don't want to provide the type
+  // 'precompiled-header' if it was inferred from the file extension
+  if (Args.hasArg(options::OPT_verify_pch) && Input.getType() == types::TY_PCH)
+    return;
+
+  CmdArgs.push_back("-x");
+  if (Args.hasArg(options::OPT_rewrite_objc))
+    CmdArgs.push_back(types::getTypeName(types::TY_PP_ObjCXX));
+  else
+    CmdArgs.push_back(types::getTypeName(Input.getType()));
+}
+
+static void appendUserToPath(SmallVectorImpl<char> &Result) {
+#ifdef LLVM_ON_UNIX
+  const char *Username = getenv("LOGNAME");
+#else
+  const char *Username = getenv("USERNAME");
+#endif
+  if (Username) {
+    // Validate that LoginName can be used in a path, and get its length.
+    size_t Len = 0;
+    for (const char *P = Username; *P; ++P, ++Len) {
+      if (!clang::isAlphanumeric(*P) && *P != '_') {
+        Username = nullptr;
+        break;
+      }
+    }
+
+    if (Username && Len > 0) {
+      Result.append(Username, Username + Len);
+      return;
+    }
+  }
+
+// Fallback to user id.
+#ifdef LLVM_ON_UNIX
+  std::string UID = llvm::utostr(getuid());
+#else
+  // FIXME: Windows seems to have an 'SID' that might work.
+  std::string UID = "9999";
+#endif
+  Result.append(UID.begin(), UID.end());
+}
+
+static void addPGOAndCoverageFlags(Compilation &C, const Driver &D,
+                                   const InputInfo &Output, const ArgList &Args,
+                                   ArgStringList &CmdArgs) {
+
+  auto *PGOGenerateArg = Args.getLastArg(options::OPT_fprofile_generate,
+                                         options::OPT_fprofile_generate_EQ,
+                                         options::OPT_fno_profile_generate);
+  if (PGOGenerateArg &&
+      PGOGenerateArg->getOption().matches(options::OPT_fno_profile_generate))
+    PGOGenerateArg = nullptr;
+
+  auto *ProfileGenerateArg = Args.getLastArg(
+      options::OPT_fprofile_instr_generate,
+      options::OPT_fprofile_instr_generate_EQ,
+      options::OPT_fno_profile_instr_generate);
+  if (ProfileGenerateArg &&
+      ProfileGenerateArg->getOption().matches(
+          options::OPT_fno_profile_instr_generate))
+    ProfileGenerateArg = nullptr;
+
+  if (PGOGenerateArg && ProfileGenerateArg)
+    D.Diag(diag::err_drv_argument_not_allowed_with)
+        << PGOGenerateArg->getSpelling() << ProfileGenerateArg->getSpelling();
+
+  auto *ProfileUseArg = getLastProfileUseArg(Args);
+
+  if (PGOGenerateArg && ProfileUseArg)
+    D.Diag(diag::err_drv_argument_not_allowed_with)
+        << ProfileUseArg->getSpelling() << PGOGenerateArg->getSpelling();
+
+  if (ProfileGenerateArg && ProfileUseArg)
+    D.Diag(diag::err_drv_argument_not_allowed_with)
+        << ProfileGenerateArg->getSpelling() << ProfileUseArg->getSpelling();
+
+  if (ProfileGenerateArg) {
+    if (ProfileGenerateArg->getOption().matches(
+            options::OPT_fprofile_instr_generate_EQ))
+      CmdArgs.push_back(Args.MakeArgString(Twine("-fprofile-instrument-path=") +
+                                           ProfileGenerateArg->getValue()));
+    // The default is to use Clang Instrumentation.
+    CmdArgs.push_back("-fprofile-instrument=clang");
+  }
+
+  if (PGOGenerateArg) {
+    CmdArgs.push_back("-fprofile-instrument=llvm");
+    if (PGOGenerateArg->getOption().matches(
+            options::OPT_fprofile_generate_EQ)) {
+      SmallString<128> Path(PGOGenerateArg->getValue());
+      llvm::sys::path::append(Path, "default_%m.profraw");
+      CmdArgs.push_back(
+          Args.MakeArgString(Twine("-fprofile-instrument-path=") + Path));
+    }
+  }
+
+  if (ProfileUseArg) {
+    if (ProfileUseArg->getOption().matches(options::OPT_fprofile_instr_use_EQ))
+      CmdArgs.push_back(Args.MakeArgString(
+          Twine("-fprofile-instrument-use-path=") + ProfileUseArg->getValue()));
+    else if ((ProfileUseArg->getOption().matches(
+                  options::OPT_fprofile_use_EQ) ||
+              ProfileUseArg->getOption().matches(
+                  options::OPT_fprofile_instr_use))) {
+      SmallString<128> Path(
+          ProfileUseArg->getNumValues() == 0 ? "" : ProfileUseArg->getValue());
+      if (Path.empty() || llvm::sys::fs::is_directory(Path))
+        llvm::sys::path::append(Path, "default.profdata");
+      CmdArgs.push_back(
+          Args.MakeArgString(Twine("-fprofile-instrument-use-path=") + Path));
+    }
+  }
+
+  if (Args.hasArg(options::OPT_ftest_coverage) ||
+      Args.hasArg(options::OPT_coverage))
+    CmdArgs.push_back("-femit-coverage-notes");
+  if (Args.hasFlag(options::OPT_fprofile_arcs, options::OPT_fno_profile_arcs,
+                   false) ||
+      Args.hasArg(options::OPT_coverage))
+    CmdArgs.push_back("-femit-coverage-data");
+
+  if (Args.hasFlag(options::OPT_fcoverage_mapping,
+                   options::OPT_fno_coverage_mapping, false) &&
+      !ProfileGenerateArg)
+    D.Diag(clang::diag::err_drv_argument_only_allowed_with)
+        << "-fcoverage-mapping"
+        << "-fprofile-instr-generate";
+
+  if (Args.hasFlag(options::OPT_fcoverage_mapping,
+                   options::OPT_fno_coverage_mapping, false))
+    CmdArgs.push_back("-fcoverage-mapping");
+
+  if (C.getArgs().hasArg(options::OPT_c) ||
+      C.getArgs().hasArg(options::OPT_S)) {
+    if (Output.isFilename()) {
+      CmdArgs.push_back("-coverage-notes-file");
+      SmallString<128> OutputFilename;
+      if (Arg *FinalOutput = C.getArgs().getLastArg(options::OPT_o))
+        OutputFilename = FinalOutput->getValue();
+      else
+        OutputFilename = llvm::sys::path::filename(Output.getBaseInput());
+      SmallString<128> CoverageFilename = OutputFilename;
+      if (llvm::sys::path::is_relative(CoverageFilename)) {
+        SmallString<128> Pwd;
+        if (!llvm::sys::fs::current_path(Pwd)) {
+          llvm::sys::path::append(Pwd, CoverageFilename);
+          CoverageFilename.swap(Pwd);
+        }
+      }
+      llvm::sys::path::replace_extension(CoverageFilename, "gcno");
+      CmdArgs.push_back(Args.MakeArgString(CoverageFilename));
+
+      // Leave -fprofile-dir= an unused argument unless .gcda emission is
+      // enabled. To be polite, with '-fprofile-arcs -fno-profile-arcs' consider
+      // the flag used. There is no -fno-profile-dir, so the user has no
+      // targeted way to suppress the warning.
+      if (Args.hasArg(options::OPT_fprofile_arcs) ||
+          Args.hasArg(options::OPT_coverage)) {
+        CmdArgs.push_back("-coverage-data-file");
+        if (Arg *FProfileDir = Args.getLastArg(options::OPT_fprofile_dir)) {
+          CoverageFilename = FProfileDir->getValue();
+          llvm::sys::path::append(CoverageFilename, OutputFilename);
+        }
+        llvm::sys::path::replace_extension(CoverageFilename, "gcda");
+        CmdArgs.push_back(Args.MakeArgString(CoverageFilename));
+      }
+    }
+  }
+}
+
+/// \brief Check whether the given input tree contains any compilation actions.
+static bool ContainsCompileAction(const Action *A) {
+  if (isa<CompileJobAction>(A) || isa<BackendJobAction>(A))
+    return true;
+
+  for (const auto &AI : A->inputs())
+    if (ContainsCompileAction(AI))
+      return true;
+
+  return false;
+}
+
+/// \brief Check if -relax-all should be passed to the internal assembler.
+/// This is done by default when compiling non-assembler source with -O0.
+static bool UseRelaxAll(Compilation &C, const ArgList &Args) {
+  bool RelaxDefault = true;
+
+  if (Arg *A = Args.getLastArg(options::OPT_O_Group))
+    RelaxDefault = A->getOption().matches(options::OPT_O0);
+
+  if (RelaxDefault) {
+    RelaxDefault = false;
+    for (const auto &Act : C.getActions()) {
+      if (ContainsCompileAction(Act)) {
+        RelaxDefault = true;
+        break;
+      }
+    }
+  }
+
+  return Args.hasFlag(options::OPT_mrelax_all, options::OPT_mno_relax_all,
+                      RelaxDefault);
+}
+
+// Extract the integer N from a string spelled "-dwarf-N", returning 0
+// on mismatch. The StringRef input (rather than an Arg) allows
+// for use by the "-Xassembler" option parser.
+static unsigned DwarfVersionNum(StringRef ArgValue) {
+  return llvm::StringSwitch<unsigned>(ArgValue)
+      .Case("-gdwarf-2", 2)
+      .Case("-gdwarf-3", 3)
+      .Case("-gdwarf-4", 4)
+      .Case("-gdwarf-5", 5)
+      .Default(0);
+}
+
+static void RenderDebugEnablingArgs(const ArgList &Args, ArgStringList &CmdArgs,
+                                    codegenoptions::DebugInfoKind DebugInfoKind,
+                                    unsigned DwarfVersion,
+                                    llvm::DebuggerKind DebuggerTuning) {
+  switch (DebugInfoKind) {
+  case codegenoptions::DebugLineTablesOnly:
+    CmdArgs.push_back("-debug-info-kind=line-tables-only");
+    break;
+  case codegenoptions::LimitedDebugInfo:
+    CmdArgs.push_back("-debug-info-kind=limited");
+    break;
+  case codegenoptions::FullDebugInfo:
+    CmdArgs.push_back("-debug-info-kind=standalone");
+    break;
+  default:
+    break;
+  }
+  if (DwarfVersion > 0)
+    CmdArgs.push_back(
+        Args.MakeArgString("-dwarf-version=" + Twine(DwarfVersion)));
+  switch (DebuggerTuning) {
+  case llvm::DebuggerKind::GDB:
+    CmdArgs.push_back("-debugger-tuning=gdb");
+    break;
+  case llvm::DebuggerKind::LLDB:
+    CmdArgs.push_back("-debugger-tuning=lldb");
+    break;
+  case llvm::DebuggerKind::SCE:
+    CmdArgs.push_back("-debugger-tuning=sce");
+    break;
+  default:
+    break;
+  }
+}
+
+static const char *RelocationModelName(llvm::Reloc::Model Model) {
+  switch (Model) {
+  case llvm::Reloc::Static:
+    return "static";
+  case llvm::Reloc::PIC_:
+    return "pic";
+  case llvm::Reloc::DynamicNoPIC:
+    return "dynamic-no-pic";
+  case llvm::Reloc::ROPI:
+    return "ropi";
+  case llvm::Reloc::RWPI:
+    return "rwpi";
+  case llvm::Reloc::ROPI_RWPI:
+    return "ropi-rwpi";
+  }
+  llvm_unreachable("Unknown Reloc::Model kind");
+}
+
+void Clang::AddPreprocessingOptions(Compilation &C, const JobAction &JA,
+                                    const Driver &D, const ArgList &Args,
+                                    ArgStringList &CmdArgs,
+                                    const InputInfo &Output,
+                                    const InputInfoList &Inputs) const {
+  Arg *A;
+  const bool IsIAMCU = getToolChain().getTriple().isOSIAMCU();
+
+  CheckPreprocessingOptions(D, Args);
+
+  Args.AddLastArg(CmdArgs, options::OPT_C);
+  Args.AddLastArg(CmdArgs, options::OPT_CC);
+
+  // Handle dependency file generation.
+  if ((A = Args.getLastArg(options::OPT_M, options::OPT_MM)) ||
+      (A = Args.getLastArg(options::OPT_MD)) ||
+      (A = Args.getLastArg(options::OPT_MMD))) {
+    // Determine the output location.
+    const char *DepFile;
+    if (Arg *MF = Args.getLastArg(options::OPT_MF)) {
+      DepFile = MF->getValue();
+      C.addFailureResultFile(DepFile, &JA);
+    } else if (Output.getType() == types::TY_Dependencies) {
+      DepFile = Output.getFilename();
+    } else if (A->getOption().matches(options::OPT_M) ||
+               A->getOption().matches(options::OPT_MM)) {
+      DepFile = "-";
+    } else {
+      DepFile = getDependencyFileName(Args, Inputs);
+      C.addFailureResultFile(DepFile, &JA);
+    }
+    CmdArgs.push_back("-dependency-file");
+    CmdArgs.push_back(DepFile);
+
+    // Add a default target if one wasn't specified.
+    if (!Args.hasArg(options::OPT_MT) && !Args.hasArg(options::OPT_MQ)) {
+      const char *DepTarget;
+
+      // If user provided -o, that is the dependency target, except
+      // when we are only generating a dependency file.
+      Arg *OutputOpt = Args.getLastArg(options::OPT_o);
+      if (OutputOpt && Output.getType() != types::TY_Dependencies) {
+        DepTarget = OutputOpt->getValue();
+      } else {
+        // Otherwise derive from the base input.
+        //
+        // FIXME: This should use the computed output file location.
+        SmallString<128> P(Inputs[0].getBaseInput());
+        llvm::sys::path::replace_extension(P, "o");
+        DepTarget = Args.MakeArgString(llvm::sys::path::filename(P));
+      }
+
+      CmdArgs.push_back("-MT");
+      SmallString<128> Quoted;
+      QuoteTarget(DepTarget, Quoted);
+      CmdArgs.push_back(Args.MakeArgString(Quoted));
+    }
+
+    if (A->getOption().matches(options::OPT_M) ||
+        A->getOption().matches(options::OPT_MD))
+      CmdArgs.push_back("-sys-header-deps");
+    if ((isa<PrecompileJobAction>(JA) &&
+         !Args.hasArg(options::OPT_fno_module_file_deps)) ||
+        Args.hasArg(options::OPT_fmodule_file_deps))
+      CmdArgs.push_back("-module-file-deps");
+  }
+
+  if (Args.hasArg(options::OPT_MG)) {
+    if (!A || A->getOption().matches(options::OPT_MD) ||
+        A->getOption().matches(options::OPT_MMD))
+      D.Diag(diag::err_drv_mg_requires_m_or_mm);
+    CmdArgs.push_back("-MG");
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_MP);
+  Args.AddLastArg(CmdArgs, options::OPT_MV);
+
+  // Convert all -MQ <target> args to -MT <quoted target>
+  for (const Arg *A : Args.filtered(options::OPT_MT, options::OPT_MQ)) {
+    A->claim();
+
+    if (A->getOption().matches(options::OPT_MQ)) {
+      CmdArgs.push_back("-MT");
+      SmallString<128> Quoted;
+      QuoteTarget(A->getValue(), Quoted);
+      CmdArgs.push_back(Args.MakeArgString(Quoted));
+
+      // -MT flag - no change
+    } else {
+      A->render(Args, CmdArgs);
+    }
+  }
+
+  // Add offload include arguments specific for CUDA.  This must happen before
+  // we -I or -include anything else, because we must pick up the CUDA headers
+  // from the particular CUDA installation, rather than from e.g.
+  // /usr/local/include.
+  if (JA.isOffloading(Action::OFK_Cuda))
+    getToolChain().AddCudaIncludeArgs(Args, CmdArgs);
+
+  // Add -i* options, and automatically translate to
+  // -include-pch/-include-pth for transparent PCH support. It's
+  // wonky, but we include looking for .gch so we can support seamless
+  // replacement into a build system already set up to be generating
+  // .gch files.
+  int YcIndex = -1, YuIndex = -1;
+  {
+    int AI = -1;
+    const Arg *YcArg = Args.getLastArg(options::OPT__SLASH_Yc);
+    const Arg *YuArg = Args.getLastArg(options::OPT__SLASH_Yu);
+    for (const Arg *A : Args.filtered(options::OPT_clang_i_Group)) {
+      // Walk the whole i_Group and skip non "-include" flags so that the index
+      // here matches the index in the next loop below.
+      ++AI;
+      if (!A->getOption().matches(options::OPT_include))
+        continue;
+      if (YcArg && strcmp(A->getValue(), YcArg->getValue()) == 0)
+        YcIndex = AI;
+      if (YuArg && strcmp(A->getValue(), YuArg->getValue()) == 0)
+        YuIndex = AI;
+    }
+  }
+  if (isa<PrecompileJobAction>(JA) && YcIndex != -1) {
+    Driver::InputList Inputs;
+    D.BuildInputs(getToolChain(), C.getArgs(), Inputs);
+    assert(Inputs.size() == 1 && "Need one input when building pch");
+    CmdArgs.push_back(Args.MakeArgString(Twine("-find-pch-source=") +
+                                         Inputs[0].second->getValue()));
+  }
+
+  bool RenderedImplicitInclude = false;
+  int AI = -1;
+  for (const Arg *A : Args.filtered(options::OPT_clang_i_Group)) {
+    ++AI;
+
+    if (getToolChain().getDriver().IsCLMode() &&
+        A->getOption().matches(options::OPT_include)) {
+      // In clang-cl mode, /Ycfoo.h means that all code up to a foo.h
+      // include is compiled into foo.h, and everything after goes into
+      // the .obj file. /Yufoo.h means that all includes prior to and including
+      // foo.h are completely skipped and replaced with a use of the pch file
+      // for foo.h.  (Each flag can have at most one value, multiple /Yc flags
+      // just mean that the last one wins.)  If /Yc and /Yu are both present
+      // and refer to the same file, /Yc wins.
+      // Note that OPT__SLASH_FI gets mapped to OPT_include.
+      // FIXME: The code here assumes that /Yc and /Yu refer to the same file.
+      // cl.exe seems to support both flags with different values, but that
+      // seems strange (which flag does /Fp now refer to?), so don't implement
+      // that until someone needs it.
+      int PchIndex = YcIndex != -1 ? YcIndex : YuIndex;
+      if (PchIndex != -1) {
+        if (isa<PrecompileJobAction>(JA)) {
+          // When building the pch, skip all includes after the pch.
+          assert(YcIndex != -1 && PchIndex == YcIndex);
+          if (AI >= YcIndex)
+            continue;
+        } else {
+          // When using the pch, skip all includes prior to the pch.
+          if (AI < PchIndex) {
+            A->claim();
+            continue;
+          }
+          if (AI == PchIndex) {
+            A->claim();
+            CmdArgs.push_back("-include-pch");
+            CmdArgs.push_back(
+                Args.MakeArgString(D.GetClPchPath(C, A->getValue())));
+            continue;
+          }
+        }
+      }
+    } else if (A->getOption().matches(options::OPT_include)) {
+      // Handling of gcc-style gch precompiled headers.
+      bool IsFirstImplicitInclude = !RenderedImplicitInclude;
+      RenderedImplicitInclude = true;
+
+      // Use PCH if the user requested it.
+      bool UsePCH = D.CCCUsePCH;
+
+      bool FoundPTH = false;
+      bool FoundPCH = false;
+      SmallString<128> P(A->getValue());
+      // We want the files to have a name like foo.h.pch. Add a dummy extension
+      // so that replace_extension does the right thing.
+      P += ".dummy";
+      if (UsePCH) {
+        llvm::sys::path::replace_extension(P, "pch");
+        if (llvm::sys::fs::exists(P))
+          FoundPCH = true;
+      }
+
+      if (!FoundPCH) {
+        llvm::sys::path::replace_extension(P, "pth");
+        if (llvm::sys::fs::exists(P))
+          FoundPTH = true;
+      }
+
+      if (!FoundPCH && !FoundPTH) {
+        llvm::sys::path::replace_extension(P, "gch");
+        if (llvm::sys::fs::exists(P)) {
+          FoundPCH = UsePCH;
+          FoundPTH = !UsePCH;
+        }
+      }
+
+      if (FoundPCH || FoundPTH) {
+        if (IsFirstImplicitInclude) {
+          A->claim();
+          if (UsePCH)
+            CmdArgs.push_back("-include-pch");
+          else
+            CmdArgs.push_back("-include-pth");
+          CmdArgs.push_back(Args.MakeArgString(P));
+          continue;
+        } else {
+          // Ignore the PCH if not first on command line and emit warning.
+          D.Diag(diag::warn_drv_pch_not_first_include) << P
+                                                       << A->getAsString(Args);
+        }
+      }
+    } else if (A->getOption().matches(options::OPT_isystem_after)) {
+      // Handling of paths which must come late.  These entries are handled by
+      // the toolchain itself after the resource dir is inserted in the right
+      // search order.
+      // Do not claim the argument so that the use of the argument does not
+      // silently go unnoticed on toolchains which do not honour the option.
+      continue;
+    }
+
+    // Not translated, render as usual.
+    A->claim();
+    A->render(Args, CmdArgs);
+  }
+
+  Args.AddAllArgs(CmdArgs,
+                  {options::OPT_D, options::OPT_U, options::OPT_I_Group,
+                   options::OPT_F, options::OPT_index_header_map});
+
+  // Add -Wp, and -Xpreprocessor if using the preprocessor.
+
+  // FIXME: There is a very unfortunate problem here, some troubled
+  // souls abuse -Wp, to pass preprocessor options in gcc syntax. To
+  // really support that we would have to parse and then translate
+  // those options. :(
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wp_COMMA,
+                       options::OPT_Xpreprocessor);
+
+  // -I- is a deprecated GCC feature, reject it.
+  if (Arg *A = Args.getLastArg(options::OPT_I_))
+    D.Diag(diag::err_drv_I_dash_not_supported) << A->getAsString(Args);
+
+  // If we have a --sysroot, and don't have an explicit -isysroot flag, add an
+  // -isysroot to the CC1 invocation.
+  StringRef sysroot = C.getSysRoot();
+  if (sysroot != "") {
+    if (!Args.hasArg(options::OPT_isysroot)) {
+      CmdArgs.push_back("-isysroot");
+      CmdArgs.push_back(C.getArgs().MakeArgString(sysroot));
+    }
+  }
+
+  // Parse additional include paths from environment variables.
+  // FIXME: We should probably sink the logic for handling these from the
+  // frontend into the driver. It will allow deleting 4 otherwise unused flags.
+  // CPATH - included following the user specified includes (but prior to
+  // builtin and standard includes).
+  addDirectoryList(Args, CmdArgs, "-I", "CPATH");
+  // C_INCLUDE_PATH - system includes enabled when compiling C.
+  addDirectoryList(Args, CmdArgs, "-c-isystem", "C_INCLUDE_PATH");
+  // CPLUS_INCLUDE_PATH - system includes enabled when compiling C++.
+  addDirectoryList(Args, CmdArgs, "-cxx-isystem", "CPLUS_INCLUDE_PATH");
+  // OBJC_INCLUDE_PATH - system includes enabled when compiling ObjC.
+  addDirectoryList(Args, CmdArgs, "-objc-isystem", "OBJC_INCLUDE_PATH");
+  // OBJCPLUS_INCLUDE_PATH - system includes enabled when compiling ObjC++.
+  addDirectoryList(Args, CmdArgs, "-objcxx-isystem", "OBJCPLUS_INCLUDE_PATH");
+
+  // While adding the include arguments, we also attempt to retrieve the
+  // arguments of related offloading toolchains or arguments that are specific
+  // of an offloading programming model.
+
+  // Add C++ include arguments, if needed.
+  if (types::isCXX(Inputs[0].getType()))
+    forAllAssociatedToolChains(C, JA, getToolChain(),
+                               [&Args, &CmdArgs](const ToolChain &TC) {
+                                 TC.AddClangCXXStdlibIncludeArgs(Args, CmdArgs);
+                               });
+
+  // Add system include arguments for all targets but IAMCU.
+  if (!IsIAMCU)
+    forAllAssociatedToolChains(C, JA, getToolChain(),
+                               [&Args, &CmdArgs](const ToolChain &TC) {
+                                 TC.AddClangSystemIncludeArgs(Args, CmdArgs);
+                               });
+  else {
+    // For IAMCU add special include arguments.
+    getToolChain().AddIAMCUIncludeArgs(Args, CmdArgs);
+  }
+}
+
+// FIXME: Move to target hook.
+static bool isSignedCharDefault(const llvm::Triple &Triple) {
+  switch (Triple.getArch()) {
+  default:
+    return true;
+
+  case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_be:
+  case llvm::Triple::arm:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumb:
+  case llvm::Triple::thumbeb:
+    if (Triple.isOSDarwin() || Triple.isOSWindows())
+      return true;
+    return false;
+
+  case llvm::Triple::ppc:
+  case llvm::Triple::ppc64:
+    if (Triple.isOSDarwin())
+      return true;
+    return false;
+
+  case llvm::Triple::hexagon:
+  case llvm::Triple::ppc64le:
+  case llvm::Triple::systemz:
+  case llvm::Triple::xcore:
+    return false;
+  }
+}
+
+static bool isNoCommonDefault(const llvm::Triple &Triple) {
+  switch (Triple.getArch()) {
+  default:
+    return false;
+
+  case llvm::Triple::xcore:
+  case llvm::Triple::wasm32:
+  case llvm::Triple::wasm64:
+    return true;
+  }
+}
+
+void Clang::AddARMTargetArgs(const llvm::Triple &Triple, const ArgList &Args,
+                             ArgStringList &CmdArgs, bool KernelOrKext) const {
+  // Select the ABI to use.
+  // FIXME: Support -meabi.
+  // FIXME: Parts of this are duplicated in the backend, unify this somehow.
+  const char *ABIName = nullptr;
+  if (Arg *A = Args.getLastArg(options::OPT_mabi_EQ)) {
+    ABIName = A->getValue();
+  } else if (Triple.isOSBinFormatMachO()) {
+    if (arm::useAAPCSForMachO(Triple)) {
+      ABIName = "aapcs";
+    } else if (Triple.isWatchABI()) {
+      ABIName = "aapcs16";
+    } else {
+      ABIName = "apcs-gnu";
+    }
+  } else if (Triple.isOSWindows()) {
+    // FIXME: this is invalid for WindowsCE
+    ABIName = "aapcs";
+  } else {
+    // Select the default based on the platform.
+    switch (Triple.getEnvironment()) {
+    case llvm::Triple::Android:
+    case llvm::Triple::GNUEABI:
+    case llvm::Triple::GNUEABIHF:
+    case llvm::Triple::MuslEABI:
+    case llvm::Triple::MuslEABIHF:
+      ABIName = "aapcs-linux";
+      break;
+    case llvm::Triple::EABIHF:
+    case llvm::Triple::EABI:
+      ABIName = "aapcs";
+      break;
+    default:
+      if (Triple.getOS() == llvm::Triple::NetBSD)
+        ABIName = "apcs-gnu";
+      else if (Triple.getOS() == llvm::Triple::OpenBSD)
+        ABIName = "aapcs-linux";
+      else
+        ABIName = "aapcs";
+      break;
+    }
+  }
+  CmdArgs.push_back("-target-abi");
+  CmdArgs.push_back(ABIName);
+
+  // Determine floating point ABI from the options & target defaults.
+  arm::FloatABI ABI = arm::getARMFloatABI(getToolChain(), Args);
+  if (ABI == arm::FloatABI::Soft) {
+    // Floating point operations and argument passing are soft.
+    // FIXME: This changes CPP defines, we need -target-soft-float.
+    CmdArgs.push_back("-msoft-float");
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("soft");
+  } else if (ABI == arm::FloatABI::SoftFP) {
+    // Floating point operations are hard, but argument passing is soft.
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("soft");
+  } else {
+    // Floating point operations and argument passing are hard.
+    assert(ABI == arm::FloatABI::Hard && "Invalid float abi!");
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("hard");
+  }
+
+  // Forward the -mglobal-merge option for explicit control over the pass.
+  if (Arg *A = Args.getLastArg(options::OPT_mglobal_merge,
+                               options::OPT_mno_global_merge)) {
+    CmdArgs.push_back("-backend-option");
+    if (A->getOption().matches(options::OPT_mno_global_merge))
+      CmdArgs.push_back("-arm-global-merge=false");
+    else
+      CmdArgs.push_back("-arm-global-merge=true");
+  }
+
+  if (!Args.hasFlag(options::OPT_mimplicit_float,
+                    options::OPT_mno_implicit_float, true))
+    CmdArgs.push_back("-no-implicit-float");
+}
+
+void Clang::AddAArch64TargetArgs(const ArgList &Args,
+                                 ArgStringList &CmdArgs) const {
+  const llvm::Triple &Triple = getToolChain().getEffectiveTriple();
+
+  if (!Args.hasFlag(options::OPT_mred_zone, options::OPT_mno_red_zone, true) ||
+      Args.hasArg(options::OPT_mkernel) ||
+      Args.hasArg(options::OPT_fapple_kext))
+    CmdArgs.push_back("-disable-red-zone");
+
+  if (!Args.hasFlag(options::OPT_mimplicit_float,
+                    options::OPT_mno_implicit_float, true))
+    CmdArgs.push_back("-no-implicit-float");
+
+  const char *ABIName = nullptr;
+  if (Arg *A = Args.getLastArg(options::OPT_mabi_EQ))
+    ABIName = A->getValue();
+  else if (Triple.isOSDarwin())
+    ABIName = "darwinpcs";
+  else
+    ABIName = "aapcs";
+
+  CmdArgs.push_back("-target-abi");
+  CmdArgs.push_back(ABIName);
+
+  if (Arg *A = Args.getLastArg(options::OPT_mfix_cortex_a53_835769,
+                               options::OPT_mno_fix_cortex_a53_835769)) {
+    CmdArgs.push_back("-backend-option");
+    if (A->getOption().matches(options::OPT_mfix_cortex_a53_835769))
+      CmdArgs.push_back("-aarch64-fix-cortex-a53-835769=1");
+    else
+      CmdArgs.push_back("-aarch64-fix-cortex-a53-835769=0");
+  } else if (Triple.isAndroid()) {
+    // Enabled A53 errata (835769) workaround by default on android
+    CmdArgs.push_back("-backend-option");
+    CmdArgs.push_back("-aarch64-fix-cortex-a53-835769=1");
+  }
+
+  // Forward the -mglobal-merge option for explicit control over the pass.
+  if (Arg *A = Args.getLastArg(options::OPT_mglobal_merge,
+                               options::OPT_mno_global_merge)) {
+    CmdArgs.push_back("-backend-option");
+    if (A->getOption().matches(options::OPT_mno_global_merge))
+      CmdArgs.push_back("-aarch64-enable-global-merge=false");
+    else
+      CmdArgs.push_back("-aarch64-enable-global-merge=true");
+  }
+}
+
+void Clang::AddMIPSTargetArgs(const ArgList &Args,
+                              ArgStringList &CmdArgs) const {
+  const Driver &D = getToolChain().getDriver();
+  StringRef CPUName;
+  StringRef ABIName;
+  const llvm::Triple &Triple = getToolChain().getTriple();
+  mips::getMipsCPUAndABI(Args, Triple, CPUName, ABIName);
+
+  CmdArgs.push_back("-target-abi");
+  CmdArgs.push_back(ABIName.data());
+
+  mips::FloatABI ABI = mips::getMipsFloatABI(D, Args);
+  if (ABI == mips::FloatABI::Soft) {
+    // Floating point operations and argument passing are soft.
+    CmdArgs.push_back("-msoft-float");
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("soft");
+  } else {
+    // Floating point operations and argument passing are hard.
+    assert(ABI == mips::FloatABI::Hard && "Invalid float abi!");
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("hard");
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_mxgot, options::OPT_mno_xgot)) {
+    if (A->getOption().matches(options::OPT_mxgot)) {
+      CmdArgs.push_back("-mllvm");
+      CmdArgs.push_back("-mxgot");
+    }
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_mldc1_sdc1,
+                               options::OPT_mno_ldc1_sdc1)) {
+    if (A->getOption().matches(options::OPT_mno_ldc1_sdc1)) {
+      CmdArgs.push_back("-mllvm");
+      CmdArgs.push_back("-mno-ldc1-sdc1");
+    }
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_mcheck_zero_division,
+                               options::OPT_mno_check_zero_division)) {
+    if (A->getOption().matches(options::OPT_mno_check_zero_division)) {
+      CmdArgs.push_back("-mllvm");
+      CmdArgs.push_back("-mno-check-zero-division");
+    }
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_G)) {
+    StringRef v = A->getValue();
+    CmdArgs.push_back("-mllvm");
+    CmdArgs.push_back(Args.MakeArgString("-mips-ssection-threshold=" + v));
+    A->claim();
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_mcompact_branches_EQ)) {
+    StringRef Val = StringRef(A->getValue());
+    if (mips::hasCompactBranches(CPUName)) {
+      if (Val == "never" || Val == "always" || Val == "optimal") {
+        CmdArgs.push_back("-mllvm");
+        CmdArgs.push_back(Args.MakeArgString("-mips-compact-branches=" + Val));
+      } else
+        D.Diag(diag::err_drv_unsupported_option_argument)
+            << A->getOption().getName() << Val;
+    } else
+      D.Diag(diag::warn_target_unsupported_compact_branches) << CPUName;
+  }
+}
+
+void Clang::AddPPCTargetArgs(const ArgList &Args,
+                             ArgStringList &CmdArgs) const {
+  // Select the ABI to use.
+  const char *ABIName = nullptr;
+  if (getToolChain().getTriple().isOSLinux())
+    switch (getToolChain().getArch()) {
+    case llvm::Triple::ppc64: {
+      // When targeting a processor that supports QPX, or if QPX is
+      // specifically enabled, default to using the ABI that supports QPX (so
+      // long as it is not specifically disabled).
+      bool HasQPX = false;
+      if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ))
+        HasQPX = A->getValue() == StringRef("a2q");
+      HasQPX = Args.hasFlag(options::OPT_mqpx, options::OPT_mno_qpx, HasQPX);
+      if (HasQPX) {
+        ABIName = "elfv1-qpx";
+        break;
+      }
+
+      ABIName = "elfv1";
+      break;
+    }
+    case llvm::Triple::ppc64le:
+      ABIName = "elfv2";
+      break;
+    default:
+      break;
+    }
+
+  if (Arg *A = Args.getLastArg(options::OPT_mabi_EQ))
+    // The ppc64 linux abis are all "altivec" abis by default. Accept and ignore
+    // the option if given as we don't have backend support for any targets
+    // that don't use the altivec abi.
+    if (StringRef(A->getValue()) != "altivec")
+      ABIName = A->getValue();
+
+  ppc::FloatABI FloatABI =
+      ppc::getPPCFloatABI(getToolChain().getDriver(), Args);
+
+  if (FloatABI == ppc::FloatABI::Soft) {
+    // Floating point operations and argument passing are soft.
+    CmdArgs.push_back("-msoft-float");
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("soft");
+  } else {
+    // Floating point operations and argument passing are hard.
+    assert(FloatABI == ppc::FloatABI::Hard && "Invalid float abi!");
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("hard");
+  }
+
+  if (ABIName) {
+    CmdArgs.push_back("-target-abi");
+    CmdArgs.push_back(ABIName);
+  }
+}
+
+void Clang::AddSparcTargetArgs(const ArgList &Args,
+                               ArgStringList &CmdArgs) const {
+  sparc::FloatABI FloatABI =
+      sparc::getSparcFloatABI(getToolChain().getDriver(), Args);
+
+  if (FloatABI == sparc::FloatABI::Soft) {
+    // Floating point operations and argument passing are soft.
+    CmdArgs.push_back("-msoft-float");
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("soft");
+  } else {
+    // Floating point operations and argument passing are hard.
+    assert(FloatABI == sparc::FloatABI::Hard && "Invalid float abi!");
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("hard");
+  }
+}
+
+void Clang::AddSystemZTargetArgs(const ArgList &Args,
+                                 ArgStringList &CmdArgs) const {
+  if (Args.hasFlag(options::OPT_mbackchain, options::OPT_mno_backchain, false))
+    CmdArgs.push_back("-mbackchain");
+}
+
+void Clang::AddX86TargetArgs(const ArgList &Args,
+                             ArgStringList &CmdArgs) const {
+  if (!Args.hasFlag(options::OPT_mred_zone, options::OPT_mno_red_zone, true) ||
+      Args.hasArg(options::OPT_mkernel) ||
+      Args.hasArg(options::OPT_fapple_kext))
+    CmdArgs.push_back("-disable-red-zone");
+
+  // Default to avoid implicit floating-point for kernel/kext code, but allow
+  // that to be overridden with -mno-soft-float.
+  bool NoImplicitFloat = (Args.hasArg(options::OPT_mkernel) ||
+                          Args.hasArg(options::OPT_fapple_kext));
+  if (Arg *A = Args.getLastArg(
+          options::OPT_msoft_float, options::OPT_mno_soft_float,
+          options::OPT_mimplicit_float, options::OPT_mno_implicit_float)) {
+    const Option &O = A->getOption();
+    NoImplicitFloat = (O.matches(options::OPT_mno_implicit_float) ||
+                       O.matches(options::OPT_msoft_float));
+  }
+  if (NoImplicitFloat)
+    CmdArgs.push_back("-no-implicit-float");
+
+  if (Arg *A = Args.getLastArg(options::OPT_masm_EQ)) {
+    StringRef Value = A->getValue();
+    if (Value == "intel" || Value == "att") {
+      CmdArgs.push_back("-mllvm");
+      CmdArgs.push_back(Args.MakeArgString("-x86-asm-syntax=" + Value));
+    } else {
+      getToolChain().getDriver().Diag(diag::err_drv_unsupported_option_argument)
+          << A->getOption().getName() << Value;
+    }
+  }
+
+  // Set flags to support MCU ABI.
+  if (Args.hasFlag(options::OPT_miamcu, options::OPT_mno_iamcu, false)) {
+    CmdArgs.push_back("-mfloat-abi");
+    CmdArgs.push_back("soft");
+    CmdArgs.push_back("-mstack-alignment=4");
+  }
+}
+
+void Clang::AddHexagonTargetArgs(const ArgList &Args,
+                                 ArgStringList &CmdArgs) const {
+  CmdArgs.push_back("-mqdsp6-compat");
+  CmdArgs.push_back("-Wreturn-type");
+
+  if (auto G = toolchains::HexagonToolChain::getSmallDataThreshold(Args)) {
+    std::string N = llvm::utostr(G.getValue());
+    std::string Opt = std::string("-hexagon-small-data-threshold=") + N;
+    CmdArgs.push_back("-mllvm");
+    CmdArgs.push_back(Args.MakeArgString(Opt));
+  }
+
+  if (!Args.hasArg(options::OPT_fno_short_enums))
+    CmdArgs.push_back("-fshort-enums");
+  if (Args.getLastArg(options::OPT_mieee_rnd_near)) {
+    CmdArgs.push_back("-mllvm");
+    CmdArgs.push_back("-enable-hexagon-ieee-rnd-near");
+  }
+  CmdArgs.push_back("-mllvm");
+  CmdArgs.push_back("-machine-sink-split=0");
+}
+
+void Clang::AddLanaiTargetArgs(const ArgList &Args,
+                               ArgStringList &CmdArgs) const {
+  if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ)) {
+    StringRef CPUName = A->getValue();
+
+    CmdArgs.push_back("-target-cpu");
+    CmdArgs.push_back(Args.MakeArgString(CPUName));
+  }
+  if (Arg *A = Args.getLastArg(options::OPT_mregparm_EQ)) {
+    StringRef Value = A->getValue();
+    // Only support mregparm=4 to support old usage. Report error for all other
+    // cases.
+    int Mregparm;
+    if (Value.getAsInteger(10, Mregparm)) {
+      if (Mregparm != 4) {
+        getToolChain().getDriver().Diag(
+            diag::err_drv_unsupported_option_argument)
+            << A->getOption().getName() << Value;
+      }
+    }
+  }
+}
+
+void Clang::AddWebAssemblyTargetArgs(const ArgList &Args,
+                                     ArgStringList &CmdArgs) const {
+  // Default to "hidden" visibility.
+  if (!Args.hasArg(options::OPT_fvisibility_EQ,
+                   options::OPT_fvisibility_ms_compat)) {
+    CmdArgs.push_back("-fvisibility");
+    CmdArgs.push_back("hidden");
+  }
+}
+
+void Clang::DumpCompilationDatabase(Compilation &C, StringRef Filename,
+                                    StringRef Target, const InputInfo &Output,
+                                    const InputInfo &Input, const ArgList &Args) const {
+  // If this is a dry run, do not create the compilation database file.
+  if (C.getArgs().hasArg(options::OPT__HASH_HASH_HASH))
+    return;
+
+  using llvm::yaml::escape;
+  const Driver &D = getToolChain().getDriver();
+
+  if (!CompilationDatabase) {
+    std::error_code EC;
+    auto File = llvm::make_unique<llvm::raw_fd_ostream>(Filename, EC, llvm::sys::fs::F_Text);
+    if (EC) {
+      D.Diag(clang::diag::err_drv_compilationdatabase) << Filename
+                                                       << EC.message();
+      return;
+    }
+    CompilationDatabase = std::move(File);
+  }
+  auto &CDB = *CompilationDatabase;
+  SmallString<128> Buf;
+  if (llvm::sys::fs::current_path(Buf))
+    Buf = ".";
+  CDB << "{ \"directory\": \"" << escape(Buf) << "\"";
+  CDB << ", \"file\": \"" << escape(Input.getFilename()) << "\"";
+  CDB << ", \"output\": \"" << escape(Output.getFilename()) << "\"";
+  CDB << ", \"arguments\": [\"" << escape(D.ClangExecutable) << "\"";
+  Buf = "-x";
+  Buf += types::getTypeName(Input.getType());
+  CDB << ", \"" << escape(Buf) << "\"";
+  if (!D.SysRoot.empty() && !Args.hasArg(options::OPT__sysroot_EQ)) {
+    Buf = "--sysroot=";
+    Buf += D.SysRoot;
+    CDB << ", \"" << escape(Buf) << "\"";
+  }
+  CDB << ", \"" << escape(Input.getFilename()) << "\"";
+  for (auto &A: Args) {
+    auto &O = A->getOption();
+    // Skip language selection, which is positional.
+    if (O.getID() == options::OPT_x)
+      continue;
+    // Skip writing dependency output and the compilation database itself.
+    if (O.getGroup().isValid() && O.getGroup().getID() == options::OPT_M_Group)
+      continue;
+    // Skip inputs.
+    if (O.getKind() == Option::InputClass)
+      continue;
+    // All other arguments are quoted and appended.
+    ArgStringList ASL;
+    A->render(Args, ASL);
+    for (auto &it: ASL)
+      CDB << ", \"" << escape(it) << "\"";
+  }
+  Buf = "--target=";
+  Buf += Target;
+  CDB << ", \"" << escape(Buf) << "\"]},\n";
+}
+
+static void CollectArgsForIntegratedAssembler(Compilation &C,
+                                              const ArgList &Args,
+                                              ArgStringList &CmdArgs,
+                                              const Driver &D) {
+  if (UseRelaxAll(C, Args))
+    CmdArgs.push_back("-mrelax-all");
+
+  // Only default to -mincremental-linker-compatible if we think we are
+  // targeting the MSVC linker.
+  bool DefaultIncrementalLinkerCompatible =
+      C.getDefaultToolChain().getTriple().isWindowsMSVCEnvironment();
+  if (Args.hasFlag(options::OPT_mincremental_linker_compatible,
+                   options::OPT_mno_incremental_linker_compatible,
+                   DefaultIncrementalLinkerCompatible))
+    CmdArgs.push_back("-mincremental-linker-compatible");
+
+  switch (C.getDefaultToolChain().getArch()) {
+  case llvm::Triple::arm:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumb:
+  case llvm::Triple::thumbeb:
+    if (Arg *A = Args.getLastArg(options::OPT_mimplicit_it_EQ)) {
+      StringRef Value = A->getValue();
+      if (Value == "always" || Value == "never" || Value == "arm" ||
+          Value == "thumb") {
+        CmdArgs.push_back("-mllvm");
+        CmdArgs.push_back(Args.MakeArgString("-arm-implicit-it=" + Value));
+      } else {
+        D.Diag(diag::err_drv_unsupported_option_argument)
+            << A->getOption().getName() << Value;
+      }
+    }
+    break;
+  default:
+    break;
+  }
+
+  // When passing -I arguments to the assembler we sometimes need to
+  // unconditionally take the next argument.  For example, when parsing
+  // '-Wa,-I -Wa,foo' we need to accept the -Wa,foo arg after seeing the
+  // -Wa,-I arg and when parsing '-Wa,-I,foo' we need to accept the 'foo'
+  // arg after parsing the '-I' arg.
+  bool TakeNextArg = false;
+
+  // When using an integrated assembler, translate -Wa, and -Xassembler
+  // options.
+  bool CompressDebugSections = false;
+
+  bool UseRelaxRelocations = ENABLE_X86_RELAX_RELOCATIONS;
+  const char *MipsTargetFeature = nullptr;
+  for (const Arg *A :
+       Args.filtered(options::OPT_Wa_COMMA, options::OPT_Xassembler)) {
+    A->claim();
+
+    for (StringRef Value : A->getValues()) {
+      if (TakeNextArg) {
+        CmdArgs.push_back(Value.data());
+        TakeNextArg = false;
+        continue;
+      }
+
+      if (C.getDefaultToolChain().getTriple().isOSBinFormatCOFF() &&
+          Value == "-mbig-obj")
+        continue; // LLVM handles bigobj automatically
+
+      switch (C.getDefaultToolChain().getArch()) {
+      default:
+        break;
+      case llvm::Triple::mips:
+      case llvm::Triple::mipsel:
+      case llvm::Triple::mips64:
+      case llvm::Triple::mips64el:
+        if (Value == "--trap") {
+          CmdArgs.push_back("-target-feature");
+          CmdArgs.push_back("+use-tcc-in-div");
+          continue;
+        }
+        if (Value == "--break") {
+          CmdArgs.push_back("-target-feature");
+          CmdArgs.push_back("-use-tcc-in-div");
+          continue;
+        }
+        if (Value.startswith("-msoft-float")) {
+          CmdArgs.push_back("-target-feature");
+          CmdArgs.push_back("+soft-float");
+          continue;
+        }
+        if (Value.startswith("-mhard-float")) {
+          CmdArgs.push_back("-target-feature");
+          CmdArgs.push_back("-soft-float");
+          continue;
+        }
+
+        MipsTargetFeature = llvm::StringSwitch<const char *>(Value)
+                                .Case("-mips1", "+mips1")
+                                .Case("-mips2", "+mips2")
+                                .Case("-mips3", "+mips3")
+                                .Case("-mips4", "+mips4")
+                                .Case("-mips5", "+mips5")
+                                .Case("-mips32", "+mips32")
+                                .Case("-mips32r2", "+mips32r2")
+                                .Case("-mips32r3", "+mips32r3")
+                                .Case("-mips32r5", "+mips32r5")
+                                .Case("-mips32r6", "+mips32r6")
+                                .Case("-mips64", "+mips64")
+                                .Case("-mips64r2", "+mips64r2")
+                                .Case("-mips64r3", "+mips64r3")
+                                .Case("-mips64r5", "+mips64r5")
+                                .Case("-mips64r6", "+mips64r6")
+                                .Default(nullptr);
+        if (MipsTargetFeature)
+          continue;
+      }
+
+      if (Value == "-force_cpusubtype_ALL") {
+        // Do nothing, this is the default and we don't support anything else.
+      } else if (Value == "-L") {
+        CmdArgs.push_back("-msave-temp-labels");
+      } else if (Value == "--fatal-warnings") {
+        CmdArgs.push_back("-massembler-fatal-warnings");
+      } else if (Value == "--noexecstack") {
+        CmdArgs.push_back("-mnoexecstack");
+      } else if (Value == "-compress-debug-sections" ||
+                 Value == "--compress-debug-sections") {
+        CompressDebugSections = true;
+      } else if (Value == "-nocompress-debug-sections" ||
+                 Value == "--nocompress-debug-sections") {
+        CompressDebugSections = false;
+      } else if (Value == "-mrelax-relocations=yes" ||
+                 Value == "--mrelax-relocations=yes") {
+        UseRelaxRelocations = true;
+      } else if (Value == "-mrelax-relocations=no" ||
+                 Value == "--mrelax-relocations=no") {
+        UseRelaxRelocations = false;
+      } else if (Value.startswith("-I")) {
+        CmdArgs.push_back(Value.data());
+        // We need to consume the next argument if the current arg is a plain
+        // -I. The next arg will be the include directory.
+        if (Value == "-I")
+          TakeNextArg = true;
+      } else if (Value.startswith("-gdwarf-")) {
+        // "-gdwarf-N" options are not cc1as options.
+        unsigned DwarfVersion = DwarfVersionNum(Value);
+        if (DwarfVersion == 0) { // Send it onward, and let cc1as complain.
+          CmdArgs.push_back(Value.data());
+        } else {
+          RenderDebugEnablingArgs(Args, CmdArgs,
+                                  codegenoptions::LimitedDebugInfo,
+                                  DwarfVersion, llvm::DebuggerKind::Default);
+        }
+      } else if (Value.startswith("-mcpu") || Value.startswith("-mfpu") ||
+                 Value.startswith("-mhwdiv") || Value.startswith("-march")) {
+        // Do nothing, we'll validate it later.
+      } else if (Value == "-defsym") {
+          if (A->getNumValues() != 2) {
+            D.Diag(diag::err_drv_defsym_invalid_format) << Value;
+            break;
+          }
+          const char *S = A->getValue(1);
+          auto Pair = StringRef(S).split('=');
+          auto Sym = Pair.first;
+          auto SVal = Pair.second;
+
+          if (Sym.empty() || SVal.empty()) {
+            D.Diag(diag::err_drv_defsym_invalid_format) << S;
+            break;
+          }
+          int64_t IVal;
+          if (SVal.getAsInteger(0, IVal)) {
+            D.Diag(diag::err_drv_defsym_invalid_symval) << SVal;
+            break;
+          }
+          CmdArgs.push_back(Value.data());
+          TakeNextArg = true;
+      } else {
+        D.Diag(diag::err_drv_unsupported_option_argument)
+            << A->getOption().getName() << Value;
+      }
+    }
+  }
+  if (CompressDebugSections) {
+    if (llvm::zlib::isAvailable())
+      CmdArgs.push_back("-compress-debug-sections");
+    else
+      D.Diag(diag::warn_debug_compression_unavailable);
+  }
+  if (UseRelaxRelocations)
+    CmdArgs.push_back("--mrelax-relocations");
+  if (MipsTargetFeature != nullptr) {
+    CmdArgs.push_back("-target-feature");
+    CmdArgs.push_back(MipsTargetFeature);
+  }
+}
+
+void Clang::ConstructJob(Compilation &C, const JobAction &JA,
+                         const InputInfo &Output, const InputInfoList &Inputs,
+                         const ArgList &Args, const char *LinkingOutput) const {
+  const llvm::Triple &Triple = getToolChain().getEffectiveTriple();
+  const std::string &TripleStr = Triple.getTriple();
+
+  bool KernelOrKext =
+      Args.hasArg(options::OPT_mkernel, options::OPT_fapple_kext);
+  const Driver &D = getToolChain().getDriver();
+  ArgStringList CmdArgs;
+
+  // Check number of inputs for sanity. We need at least one input.
+  assert(Inputs.size() >= 1 && "Must have at least one input.");
+  const InputInfo &Input = Inputs[0];
+  // CUDA compilation may have multiple inputs (source file + results of
+  // device-side compilations). OpenMP device jobs also take the host IR as a
+  // second input. All other jobs are expected to have exactly one
+  // input.
+  bool IsCuda = JA.isOffloading(Action::OFK_Cuda);
+  bool IsOpenMPDevice = JA.isDeviceOffloading(Action::OFK_OpenMP);
+  assert((IsCuda || (IsOpenMPDevice && Inputs.size() == 2) ||
+          Inputs.size() == 1) &&
+         "Unable to handle multiple inputs.");
+
+  bool IsWindowsGNU = getToolChain().getTriple().isWindowsGNUEnvironment();
+  bool IsWindowsCygnus =
+      getToolChain().getTriple().isWindowsCygwinEnvironment();
+  bool IsWindowsMSVC = getToolChain().getTriple().isWindowsMSVCEnvironment();
+  bool IsPS4CPU = getToolChain().getTriple().isPS4CPU();
+  bool IsIAMCU = getToolChain().getTriple().isOSIAMCU();
+
+  // Adjust IsWindowsXYZ for CUDA compilations.  Even when compiling in device
+  // mode (i.e., getToolchain().getTriple() is NVPTX, not Windows), we need to
+  // pass Windows-specific flags to cc1.
+  if (IsCuda) {
+    const llvm::Triple *AuxTriple = getToolChain().getAuxTriple();
+    IsWindowsMSVC |= AuxTriple && AuxTriple->isWindowsMSVCEnvironment();
+    IsWindowsGNU |= AuxTriple && AuxTriple->isWindowsGNUEnvironment();
+    IsWindowsCygnus |= AuxTriple && AuxTriple->isWindowsCygwinEnvironment();
+  }
+
+  // C++ is not supported for IAMCU.
+  if (IsIAMCU && types::isCXX(Input.getType()))
+    D.Diag(diag::err_drv_clang_unsupported) << "C++ for IAMCU";
+
+  // Invoke ourselves in -cc1 mode.
+  //
+  // FIXME: Implement custom jobs for internal actions.
+  CmdArgs.push_back("-cc1");
+
+  // Add the "effective" target triple.
+  CmdArgs.push_back("-triple");
+  CmdArgs.push_back(Args.MakeArgString(TripleStr));
+
+  if (const Arg *MJ = Args.getLastArg(options::OPT_MJ)) {
+    DumpCompilationDatabase(C, MJ->getValue(), TripleStr, Output, Input, Args);
+    Args.ClaimAllArgs(options::OPT_MJ);
+  }
+
+  if (IsCuda) {
+    // We have to pass the triple of the host if compiling for a CUDA device and
+    // vice-versa.
+    std::string NormalizedTriple;
+    if (JA.isDeviceOffloading(Action::OFK_Cuda))
+      NormalizedTriple = C.getSingleOffloadToolChain<Action::OFK_Host>()
+                             ->getTriple()
+                             .normalize();
+    else
+      NormalizedTriple = C.getSingleOffloadToolChain<Action::OFK_Cuda>()
+                             ->getTriple()
+                             .normalize();
+
+    CmdArgs.push_back("-aux-triple");
+    CmdArgs.push_back(Args.MakeArgString(NormalizedTriple));
+  }
+
+  if (Triple.isOSWindows() && (Triple.getArch() == llvm::Triple::arm ||
+                               Triple.getArch() == llvm::Triple::thumb)) {
+    unsigned Offset = Triple.getArch() == llvm::Triple::arm ? 4 : 6;
+    unsigned Version;
+    Triple.getArchName().substr(Offset).getAsInteger(10, Version);
+    if (Version < 7)
+      D.Diag(diag::err_target_unsupported_arch) << Triple.getArchName()
+                                                << TripleStr;
+  }
+
+  // Push all default warning arguments that are specific to
+  // the given target.  These come before user provided warning options
+  // are provided.
+  getToolChain().addClangWarningOptions(CmdArgs);
+
+  // Select the appropriate action.
+  RewriteKind rewriteKind = RK_None;
+
+  if (isa<AnalyzeJobAction>(JA)) {
+    assert(JA.getType() == types::TY_Plist && "Invalid output type.");
+    CmdArgs.push_back("-analyze");
+  } else if (isa<MigrateJobAction>(JA)) {
+    CmdArgs.push_back("-migrate");
+  } else if (isa<PreprocessJobAction>(JA)) {
+    if (Output.getType() == types::TY_Dependencies)
+      CmdArgs.push_back("-Eonly");
+    else {
+      CmdArgs.push_back("-E");
+      if (Args.hasArg(options::OPT_rewrite_objc) &&
+          !Args.hasArg(options::OPT_g_Group))
+        CmdArgs.push_back("-P");
+    }
+  } else if (isa<AssembleJobAction>(JA)) {
+    CmdArgs.push_back("-emit-obj");
+
+    CollectArgsForIntegratedAssembler(C, Args, CmdArgs, D);
+
+    // Also ignore explicit -force_cpusubtype_ALL option.
+    (void)Args.hasArg(options::OPT_force__cpusubtype__ALL);
+  } else if (isa<PrecompileJobAction>(JA)) {
+    // Use PCH if the user requested it.
+    bool UsePCH = D.CCCUsePCH;
+
+    if (JA.getType() == types::TY_Nothing)
+      CmdArgs.push_back("-fsyntax-only");
+    else if (JA.getType() == types::TY_ModuleFile)
+      CmdArgs.push_back("-emit-module-interface");
+    else if (UsePCH)
+      CmdArgs.push_back("-emit-pch");
+    else
+      CmdArgs.push_back("-emit-pth");
+  } else if (isa<VerifyPCHJobAction>(JA)) {
+    CmdArgs.push_back("-verify-pch");
+  } else {
+    assert((isa<CompileJobAction>(JA) || isa<BackendJobAction>(JA)) &&
+           "Invalid action for clang tool.");
+    if (JA.getType() == types::TY_Nothing) {
+      CmdArgs.push_back("-fsyntax-only");
+    } else if (JA.getType() == types::TY_LLVM_IR ||
+               JA.getType() == types::TY_LTO_IR) {
+      CmdArgs.push_back("-emit-llvm");
+    } else if (JA.getType() == types::TY_LLVM_BC ||
+               JA.getType() == types::TY_LTO_BC) {
+      CmdArgs.push_back("-emit-llvm-bc");
+    } else if (JA.getType() == types::TY_PP_Asm) {
+      CmdArgs.push_back("-S");
+    } else if (JA.getType() == types::TY_AST) {
+      CmdArgs.push_back("-emit-pch");
+    } else if (JA.getType() == types::TY_ModuleFile) {
+      CmdArgs.push_back("-module-file-info");
+    } else if (JA.getType() == types::TY_RewrittenObjC) {
+      CmdArgs.push_back("-rewrite-objc");
+      rewriteKind = RK_NonFragile;
+    } else if (JA.getType() == types::TY_RewrittenLegacyObjC) {
+      CmdArgs.push_back("-rewrite-objc");
+      rewriteKind = RK_Fragile;
+    } else {
+      assert(JA.getType() == types::TY_PP_Asm && "Unexpected output type!");
+    }
+
+    // Preserve use-list order by default when emitting bitcode, so that
+    // loading the bitcode up in 'opt' or 'llc' and running passes gives the
+    // same result as running passes here.  For LTO, we don't need to preserve
+    // the use-list order, since serialization to bitcode is part of the flow.
+    if (JA.getType() == types::TY_LLVM_BC)
+      CmdArgs.push_back("-emit-llvm-uselists");
+
+    if (D.isUsingLTO()) {
+      Args.AddLastArg(CmdArgs, options::OPT_flto, options::OPT_flto_EQ);
+
+      // The Darwin linker currently uses the legacy LTO API, which does not
+      // support LTO unit features (CFI, whole program vtable opt) under
+      // ThinLTO.
+      if (!getToolChain().getTriple().isOSDarwin() ||
+          D.getLTOMode() == LTOK_Full)
+        CmdArgs.push_back("-flto-unit");
+    }
+  }
+
+  if (const Arg *A = Args.getLastArg(options::OPT_fthinlto_index_EQ)) {
+    if (!types::isLLVMIR(Input.getType()))
+      D.Diag(diag::err_drv_argument_only_allowed_with) << A->getAsString(Args)
+                                                       << "-x ir";
+    Args.AddLastArg(CmdArgs, options::OPT_fthinlto_index_EQ);
+  }
+
+  // Embed-bitcode option.
+  if (C.getDriver().embedBitcodeInObject() && !C.getDriver().isUsingLTO() &&
+      (isa<BackendJobAction>(JA) || isa<AssembleJobAction>(JA))) {
+    // Add flags implied by -fembed-bitcode.
+    Args.AddLastArg(CmdArgs, options::OPT_fembed_bitcode_EQ);
+    // Disable all llvm IR level optimizations.
+    CmdArgs.push_back("-disable-llvm-passes");
+  }
+  if (C.getDriver().embedBitcodeMarkerOnly() && !C.getDriver().isUsingLTO())
+    CmdArgs.push_back("-fembed-bitcode=marker");
+
+  // We normally speed up the clang process a bit by skipping destructors at
+  // exit, but when we're generating diagnostics we can rely on some of the
+  // cleanup.
+  if (!C.isForDiagnostics())
+    CmdArgs.push_back("-disable-free");
+
+// Disable the verification pass in -asserts builds.
+#ifdef NDEBUG
+  CmdArgs.push_back("-disable-llvm-verifier");
+  // Discard LLVM value names in -asserts builds.
+  CmdArgs.push_back("-discard-value-names");
+#endif
+
+  // Set the main file name, so that debug info works even with
+  // -save-temps.
+  CmdArgs.push_back("-main-file-name");
+  CmdArgs.push_back(getBaseInputName(Args, Input));
+
+  // Some flags which affect the language (via preprocessor
+  // defines).
+  if (Args.hasArg(options::OPT_static))
+    CmdArgs.push_back("-static-define");
+
+  if (isa<AnalyzeJobAction>(JA)) {
+    // Enable region store model by default.
+    CmdArgs.push_back("-analyzer-store=region");
+
+    // Treat blocks as analysis entry points.
+    CmdArgs.push_back("-analyzer-opt-analyze-nested-blocks");
+
+    CmdArgs.push_back("-analyzer-eagerly-assume");
+
+    // Add default argument set.
+    if (!Args.hasArg(options::OPT__analyzer_no_default_checks)) {
+      CmdArgs.push_back("-analyzer-checker=core");
+      CmdArgs.push_back("-analyzer-checker=apiModeling");
+
+    if (!IsWindowsMSVC) {
+      CmdArgs.push_back("-analyzer-checker=unix");
+    } else {
+      // Enable "unix" checkers that also work on Windows.
+      CmdArgs.push_back("-analyzer-checker=unix.API");
+      CmdArgs.push_back("-analyzer-checker=unix.Malloc");
+      CmdArgs.push_back("-analyzer-checker=unix.MallocSizeof");
+      CmdArgs.push_back("-analyzer-checker=unix.MismatchedDeallocator");
+      CmdArgs.push_back("-analyzer-checker=unix.cstring.BadSizeArg");
+      CmdArgs.push_back("-analyzer-checker=unix.cstring.NullArg");
+    }
+
+      // Disable some unix checkers for PS4.
+      if (IsPS4CPU) {
+        CmdArgs.push_back("-analyzer-disable-checker=unix.API");
+        CmdArgs.push_back("-analyzer-disable-checker=unix.Vfork");
+      }
+
+      if (getToolChain().getTriple().getVendor() == llvm::Triple::Apple)
+        CmdArgs.push_back("-analyzer-checker=osx");
+
+      CmdArgs.push_back("-analyzer-checker=deadcode");
+
+      if (types::isCXX(Input.getType()))
+        CmdArgs.push_back("-analyzer-checker=cplusplus");
+
+      if (!IsPS4CPU) {
+        CmdArgs.push_back(
+            "-analyzer-checker=security.insecureAPI.UncheckedReturn");
+        CmdArgs.push_back("-analyzer-checker=security.insecureAPI.getpw");
+        CmdArgs.push_back("-analyzer-checker=security.insecureAPI.gets");
+        CmdArgs.push_back("-analyzer-checker=security.insecureAPI.mktemp");
+        CmdArgs.push_back("-analyzer-checker=security.insecureAPI.mkstemp");
+        CmdArgs.push_back("-analyzer-checker=security.insecureAPI.vfork");
+      }
+
+      // Default nullability checks.
+      CmdArgs.push_back("-analyzer-checker=nullability.NullPassedToNonnull");
+      CmdArgs.push_back(
+          "-analyzer-checker=nullability.NullReturnedFromNonnull");
+    }
+
+    // Set the output format. The default is plist, for (lame) historical
+    // reasons.
+    CmdArgs.push_back("-analyzer-output");
+    if (Arg *A = Args.getLastArg(options::OPT__analyzer_output))
+      CmdArgs.push_back(A->getValue());
+    else
+      CmdArgs.push_back("plist");
+
+    // Disable the presentation of standard compiler warnings when
+    // using --analyze.  We only want to show static analyzer diagnostics
+    // or frontend errors.
+    CmdArgs.push_back("-w");
+
+    // Add -Xanalyzer arguments when running as analyzer.
+    Args.AddAllArgValues(CmdArgs, options::OPT_Xanalyzer);
+  }
+
+  CheckCodeGenerationOptions(D, Args);
+
+  llvm::Reloc::Model RelocationModel;
+  unsigned PICLevel;
+  bool IsPIE;
+  std::tie(RelocationModel, PICLevel, IsPIE) =
+      ParsePICArgs(getToolChain(), Args);
+
+  const char *RMName = RelocationModelName(RelocationModel);
+
+  if ((RelocationModel == llvm::Reloc::ROPI ||
+       RelocationModel == llvm::Reloc::ROPI_RWPI) &&
+      types::isCXX(Input.getType()) &&
+      !Args.hasArg(options::OPT_fallow_unsupported))
+    D.Diag(diag::err_drv_ropi_incompatible_with_cxx);
+
+  if (RMName) {
+    CmdArgs.push_back("-mrelocation-model");
+    CmdArgs.push_back(RMName);
+  }
+  if (PICLevel > 0) {
+    CmdArgs.push_back("-pic-level");
+    CmdArgs.push_back(PICLevel == 1 ? "1" : "2");
+    if (IsPIE)
+      CmdArgs.push_back("-pic-is-pie");
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_meabi)) {
+    CmdArgs.push_back("-meabi");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  CmdArgs.push_back("-mthread-model");
+  if (Arg *A = Args.getLastArg(options::OPT_mthread_model))
+    CmdArgs.push_back(A->getValue());
+  else
+    CmdArgs.push_back(Args.MakeArgString(getToolChain().getThreadModel()));
+
+  Args.AddLastArg(CmdArgs, options::OPT_fveclib);
+
+  if (!Args.hasFlag(options::OPT_fmerge_all_constants,
+                    options::OPT_fno_merge_all_constants))
+    CmdArgs.push_back("-fno-merge-all-constants");
+
+  // LLVM Code Generator Options.
+
+  if (Args.hasArg(options::OPT_frewrite_map_file) ||
+      Args.hasArg(options::OPT_frewrite_map_file_EQ)) {
+    for (const Arg *A : Args.filtered(options::OPT_frewrite_map_file,
+                                      options::OPT_frewrite_map_file_EQ)) {
+      StringRef Map = A->getValue();
+      if (!llvm::sys::fs::exists(Map)) {
+        D.Diag(diag::err_drv_no_such_file) << Map;
+      } else {
+        CmdArgs.push_back("-frewrite-map-file");
+        CmdArgs.push_back(A->getValue());
+        A->claim();
+      }
+    }
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_Wframe_larger_than_EQ)) {
+    StringRef v = A->getValue();
+    CmdArgs.push_back("-mllvm");
+    CmdArgs.push_back(Args.MakeArgString("-warn-stack-size=" + v));
+    A->claim();
+  }
+
+  if (!Args.hasFlag(options::OPT_fjump_tables, options::OPT_fno_jump_tables,
+                    true))
+    CmdArgs.push_back("-fno-jump-tables");
+
+  if (!Args.hasFlag(options::OPT_fpreserve_as_comments,
+                    options::OPT_fno_preserve_as_comments, true))
+    CmdArgs.push_back("-fno-preserve-as-comments");
+
+  if (Arg *A = Args.getLastArg(options::OPT_mregparm_EQ)) {
+    CmdArgs.push_back("-mregparm");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_fpcc_struct_return,
+                               options::OPT_freg_struct_return)) {
+    if (getToolChain().getArch() != llvm::Triple::x86) {
+      D.Diag(diag::err_drv_unsupported_opt_for_target)
+          << A->getSpelling() << getToolChain().getTriple().str();
+    } else if (A->getOption().matches(options::OPT_fpcc_struct_return)) {
+      CmdArgs.push_back("-fpcc-struct-return");
+    } else {
+      assert(A->getOption().matches(options::OPT_freg_struct_return));
+      CmdArgs.push_back("-freg-struct-return");
+    }
+  }
+
+  if (Args.hasFlag(options::OPT_mrtd, options::OPT_mno_rtd, false))
+    CmdArgs.push_back("-fdefault-calling-conv=stdcall");
+
+  if (shouldUseFramePointer(Args, getToolChain().getTriple()))
+    CmdArgs.push_back("-mdisable-fp-elim");
+  if (!Args.hasFlag(options::OPT_fzero_initialized_in_bss,
+                    options::OPT_fno_zero_initialized_in_bss))
+    CmdArgs.push_back("-mno-zero-initialized-in-bss");
+
+  bool OFastEnabled = isOptimizationLevelFast(Args);
+  // If -Ofast is the optimization level, then -fstrict-aliasing should be
+  // enabled.  This alias option is being used to simplify the hasFlag logic.
+  OptSpecifier StrictAliasingAliasOption =
+      OFastEnabled ? options::OPT_Ofast : options::OPT_fstrict_aliasing;
+  // We turn strict aliasing off by default if we're in CL mode, since MSVC
+  // doesn't do any TBAA.
+  bool TBAAOnByDefault = !getToolChain().getDriver().IsCLMode();
+  if (!Args.hasFlag(options::OPT_fstrict_aliasing, StrictAliasingAliasOption,
+                    options::OPT_fno_strict_aliasing, TBAAOnByDefault))
+    CmdArgs.push_back("-relaxed-aliasing");
+  if (!Args.hasFlag(options::OPT_fstruct_path_tbaa,
+                    options::OPT_fno_struct_path_tbaa))
+    CmdArgs.push_back("-no-struct-path-tbaa");
+  if (Args.hasFlag(options::OPT_fstrict_enums, options::OPT_fno_strict_enums,
+                   false))
+    CmdArgs.push_back("-fstrict-enums");
+  if (!Args.hasFlag(options::OPT_fstrict_return, options::OPT_fno_strict_return,
+                    true))
+    CmdArgs.push_back("-fno-strict-return");
+  if (Args.hasFlag(options::OPT_fstrict_vtable_pointers,
+                   options::OPT_fno_strict_vtable_pointers,
+                   false))
+    CmdArgs.push_back("-fstrict-vtable-pointers");
+  if (!Args.hasFlag(options::OPT_foptimize_sibling_calls,
+                    options::OPT_fno_optimize_sibling_calls))
+    CmdArgs.push_back("-mdisable-tail-calls");
+
+  // Handle segmented stacks.
+  if (Args.hasArg(options::OPT_fsplit_stack))
+    CmdArgs.push_back("-split-stacks");
+
+  // Handle various floating point optimization flags, mapping them to the
+  // appropriate LLVM code generation flags. This is complicated by several
+  // "umbrella" flags, so we do this by stepping through the flags incrementally
+  // adjusting what we think is enabled/disabled, then at the end settting the
+  // LLVM flags based on the final state.
+  bool HonorInfs = true;
+  bool HonorNans = true;
+  // -fmath-errno is the default on some platforms, e.g. BSD-derived OSes.
+  bool MathErrno = getToolChain().IsMathErrnoDefault();
+  bool AssociativeMath = false;
+  bool ReciprocalMath = false;
+  bool SignedZeros = true;
+  bool TrappingMath = true;
+  StringRef DenormalFpMath = "";
+  StringRef FpContract = "";
+
+  for (Arg *A : Args) {
+    switch (A->getOption().getID()) {
+    // If this isn't an FP option skip the claim below
+    default:
+      continue;
+
+    // Options controlling individual features
+    case options::OPT_fhonor_infinities:    HonorInfs = true;        break;
+    case options::OPT_fno_honor_infinities: HonorInfs = false;       break;
+    case options::OPT_fhonor_nans:          HonorNans = true;        break;
+    case options::OPT_fno_honor_nans:       HonorNans = false;       break;
+    case options::OPT_fmath_errno:          MathErrno = true;        break;
+    case options::OPT_fno_math_errno:       MathErrno = false;       break;
+    case options::OPT_fassociative_math:    AssociativeMath = true;  break;
+    case options::OPT_fno_associative_math: AssociativeMath = false; break;
+    case options::OPT_freciprocal_math:     ReciprocalMath = true;   break;
+    case options::OPT_fno_reciprocal_math:  ReciprocalMath = false;  break;
+    case options::OPT_fsigned_zeros:        SignedZeros = true;      break;
+    case options::OPT_fno_signed_zeros:     SignedZeros = false;     break;
+    case options::OPT_ftrapping_math:       TrappingMath = true;     break;
+    case options::OPT_fno_trapping_math:    TrappingMath = false;    break;
+
+    case options::OPT_fdenormal_fp_math_EQ:
+      DenormalFpMath = A->getValue();
+      break;
+
+    // Validate and pass through -fp-contract option.
+    case options::OPT_ffp_contract: {
+      StringRef Val = A->getValue();
+      if (Val == "fast" || Val == "on" || Val == "off") {
+        FpContract = Val;
+      } else {
+        D.Diag(diag::err_drv_unsupported_option_argument)
+            << A->getOption().getName() << Val;
+      }
+      break;
+    }
+
+    case options::OPT_ffinite_math_only:
+      HonorInfs = false;
+      HonorNans = false;
+      break;
+    case options::OPT_fno_finite_math_only:
+      HonorInfs = true;
+      HonorNans = true;
+      break;
+
+    case options::OPT_funsafe_math_optimizations:
+      AssociativeMath = true;
+      ReciprocalMath = true;
+      SignedZeros = false;
+      TrappingMath = false;
+      break;
+    case options::OPT_fno_unsafe_math_optimizations:
+      AssociativeMath = false;
+      ReciprocalMath = false;
+      SignedZeros = true;
+      TrappingMath = true;
+      // -fno_unsafe_math_optimizations restores default denormal handling
+      DenormalFpMath = "";
+      break;
+
+    case options::OPT_Ofast:
+      // If -Ofast is the optimization level, then -ffast-math should be enabled
+      if (!OFastEnabled)
+        continue;
+      LLVM_FALLTHROUGH;
+    case options::OPT_ffast_math:
+      HonorInfs = false;
+      HonorNans = false;
+      MathErrno = false;
+      AssociativeMath = true;
+      ReciprocalMath = true;
+      SignedZeros = false;
+      TrappingMath = false;
+      // If fast-math is set then set the fp-contract mode to fast.
+      FpContract = "fast";
+      break;
+    case options::OPT_fno_fast_math:
+      HonorInfs = true;
+      HonorNans = true;
+      // Turning on -ffast-math (with either flag) removes the need for
+      // MathErrno. However, turning *off* -ffast-math merely restores the
+      // toolchain default (which may be false).
+      MathErrno = getToolChain().IsMathErrnoDefault();
+      AssociativeMath = false;
+      ReciprocalMath = false;
+      SignedZeros = true;
+      TrappingMath = true;
+      // -fno_fast_math restores default denormal and fpcontract handling
+      DenormalFpMath = "";
+      FpContract = "";
+      break;
+    }
+    // If we handled this option claim it
+    A->claim();
+  }
+
+  if (!HonorInfs)
+    CmdArgs.push_back("-menable-no-infs");
+
+  if (!HonorNans)
+    CmdArgs.push_back("-menable-no-nans");
+
+  if (MathErrno)
+    CmdArgs.push_back("-fmath-errno");
+
+  if (!MathErrno && AssociativeMath && ReciprocalMath && !SignedZeros &&
+      !TrappingMath)
+    CmdArgs.push_back("-menable-unsafe-fp-math");
+
+  if (!SignedZeros)
+    CmdArgs.push_back("-fno-signed-zeros");
+
+  if (ReciprocalMath)
+    CmdArgs.push_back("-freciprocal-math");
+
+  if (!TrappingMath)
+    CmdArgs.push_back("-fno-trapping-math");
+
+  if (!DenormalFpMath.empty())
+    CmdArgs.push_back(Args.MakeArgString("-fdenormal-fp-math="+DenormalFpMath));
+
+  if (!FpContract.empty())
+    CmdArgs.push_back(Args.MakeArgString("-ffp-contract="+FpContract));
+
+  ParseMRecip(getToolChain().getDriver(), Args, CmdArgs);
+
+  // -ffast-math enables the __FAST_MATH__ preprocessor macro, but check for the
+  // individual features enabled by -ffast-math instead of the option itself as
+  // that's consistent with gcc's behaviour.
+  if (!HonorInfs && !HonorNans && !MathErrno && AssociativeMath &&
+      ReciprocalMath && !SignedZeros && !TrappingMath)
+    CmdArgs.push_back("-ffast-math");
+
+  // Handle __FINITE_MATH_ONLY__ similarly.
+  if (!HonorInfs && !HonorNans)
+    CmdArgs.push_back("-ffinite-math-only");
+
+  // Decide whether to use verbose asm. Verbose assembly is the default on
+  // toolchains which have the integrated assembler on by default.
+  bool IsIntegratedAssemblerDefault =
+      getToolChain().IsIntegratedAssemblerDefault();
+  if (Args.hasFlag(options::OPT_fverbose_asm, options::OPT_fno_verbose_asm,
+                   IsIntegratedAssemblerDefault) ||
+      Args.hasArg(options::OPT_dA))
+    CmdArgs.push_back("-masm-verbose");
+
+  if (!Args.hasFlag(options::OPT_fintegrated_as, options::OPT_fno_integrated_as,
+                    IsIntegratedAssemblerDefault))
+    CmdArgs.push_back("-no-integrated-as");
+
+  if (Args.hasArg(options::OPT_fdebug_pass_structure)) {
+    CmdArgs.push_back("-mdebug-pass");
+    CmdArgs.push_back("Structure");
+  }
+  if (Args.hasArg(options::OPT_fdebug_pass_arguments)) {
+    CmdArgs.push_back("-mdebug-pass");
+    CmdArgs.push_back("Arguments");
+  }
+
+  // Enable -mconstructor-aliases except on darwin, where we have to work around
+  // a linker bug (see <rdar://problem/7651567>), and CUDA device code, where
+  // aliases aren't supported.
+  if (!getToolChain().getTriple().isOSDarwin() &&
+      !getToolChain().getTriple().isNVPTX())
+    CmdArgs.push_back("-mconstructor-aliases");
+
+  // Darwin's kernel doesn't support guard variables; just die if we
+  // try to use them.
+  if (KernelOrKext && getToolChain().getTriple().isOSDarwin())
+    CmdArgs.push_back("-fforbid-guard-variables");
+
+  if (Args.hasFlag(options::OPT_mms_bitfields, options::OPT_mno_ms_bitfields,
+                   false)) {
+    CmdArgs.push_back("-mms-bitfields");
+  }
+
+  if (Args.hasFlag(options::OPT_mpie_copy_relocations,
+                   options::OPT_mno_pie_copy_relocations,
+                   false)) {
+    CmdArgs.push_back("-mpie-copy-relocations");
+  }
+
+  // This is a coarse approximation of what llvm-gcc actually does, both
+  // -fasynchronous-unwind-tables and -fnon-call-exceptions interact in more
+  // complicated ways.
+  bool AsynchronousUnwindTables =
+      Args.hasFlag(options::OPT_fasynchronous_unwind_tables,
+                   options::OPT_fno_asynchronous_unwind_tables,
+                   (getToolChain().IsUnwindTablesDefault() ||
+                    getToolChain().getSanitizerArgs().needsUnwindTables()) &&
+                       !KernelOrKext);
+  if (Args.hasFlag(options::OPT_funwind_tables, options::OPT_fno_unwind_tables,
+                   AsynchronousUnwindTables))
+    CmdArgs.push_back("-munwind-tables");
+
+  getToolChain().addClangTargetOptions(Args, CmdArgs);
+
+  if (Arg *A = Args.getLastArg(options::OPT_flimited_precision_EQ)) {
+    CmdArgs.push_back("-mlimit-float-precision");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  // FIXME: Handle -mtune=.
+  (void)Args.hasArg(options::OPT_mtune_EQ);
+
+  if (Arg *A = Args.getLastArg(options::OPT_mcmodel_EQ)) {
+    CmdArgs.push_back("-mcode-model");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  // Add the target cpu
+  std::string CPU = getCPUName(Args, Triple, /*FromAs*/ false);
+  if (!CPU.empty()) {
+    CmdArgs.push_back("-target-cpu");
+    CmdArgs.push_back(Args.MakeArgString(CPU));
+  }
+
+  if (const Arg *A = Args.getLastArg(options::OPT_mfpmath_EQ)) {
+    CmdArgs.push_back("-mfpmath");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  // Add the target features
+  getTargetFeatures(getToolChain(), Triple, Args, CmdArgs, false);
+
+  // Add target specific flags.
+  switch (getToolChain().getArch()) {
+  default:
+    break;
+
+  case llvm::Triple::arm:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumb:
+  case llvm::Triple::thumbeb:
+    // Use the effective triple, which takes into account the deployment target.
+    AddARMTargetArgs(Triple, Args, CmdArgs, KernelOrKext);
+    break;
+
+  case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_be:
+    AddAArch64TargetArgs(Args, CmdArgs);
+    break;
+
+  case llvm::Triple::mips:
+  case llvm::Triple::mipsel:
+  case llvm::Triple::mips64:
+  case llvm::Triple::mips64el:
+    AddMIPSTargetArgs(Args, CmdArgs);
+    break;
+
+  case llvm::Triple::ppc:
+  case llvm::Triple::ppc64:
+  case llvm::Triple::ppc64le:
+    AddPPCTargetArgs(Args, CmdArgs);
+    break;
+
+  case llvm::Triple::sparc:
+  case llvm::Triple::sparcel:
+  case llvm::Triple::sparcv9:
+    AddSparcTargetArgs(Args, CmdArgs);
+    break;
+
+  case llvm::Triple::systemz:
+    AddSystemZTargetArgs(Args, CmdArgs);
+    break;
+
+  case llvm::Triple::x86:
+  case llvm::Triple::x86_64:
+    AddX86TargetArgs(Args, CmdArgs);
+    break;
+
+  case llvm::Triple::lanai:
+    AddLanaiTargetArgs(Args, CmdArgs);
+    break;
+
+  case llvm::Triple::hexagon:
+    AddHexagonTargetArgs(Args, CmdArgs);
+    break;
+
+  case llvm::Triple::wasm32:
+  case llvm::Triple::wasm64:
+    AddWebAssemblyTargetArgs(Args, CmdArgs);
+    break;
+  }
+
+  // The 'g' groups options involve a somewhat intricate sequence of decisions
+  // about what to pass from the driver to the frontend, but by the time they
+  // reach cc1 they've been factored into three well-defined orthogonal choices:
+  //  * what level of debug info to generate
+  //  * what dwarf version to write
+  //  * what debugger tuning to use
+  // This avoids having to monkey around further in cc1 other than to disable
+  // codeview if not running in a Windows environment. Perhaps even that
+  // decision should be made in the driver as well though.
+  unsigned DwarfVersion = 0;
+  llvm::DebuggerKind DebuggerTuning = getToolChain().getDefaultDebuggerTuning();
+  // These two are potentially updated by AddClangCLArgs.
+  codegenoptions::DebugInfoKind DebugInfoKind = codegenoptions::NoDebugInfo;
+  bool EmitCodeView = false;
+
+  // Add clang-cl arguments.
+  types::ID InputType = Input.getType();
+  if (getToolChain().getDriver().IsCLMode())
+    AddClangCLArgs(Args, InputType, CmdArgs, &DebugInfoKind, &EmitCodeView);
+
+  // Pass the linker version in use.
+  if (Arg *A = Args.getLastArg(options::OPT_mlinker_version_EQ)) {
+    CmdArgs.push_back("-target-linker-version");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  if (!shouldUseLeafFramePointer(Args, getToolChain().getTriple()))
+    CmdArgs.push_back("-momit-leaf-frame-pointer");
+
+  // Explicitly error on some things we know we don't support and can't just
+  // ignore.
+  if (!Args.hasArg(options::OPT_fallow_unsupported)) {
+    Arg *Unsupported;
+    if (types::isCXX(InputType) && getToolChain().getTriple().isOSDarwin() &&
+        getToolChain().getArch() == llvm::Triple::x86) {
+      if ((Unsupported = Args.getLastArg(options::OPT_fapple_kext)) ||
+          (Unsupported = Args.getLastArg(options::OPT_mkernel)))
+        D.Diag(diag::err_drv_clang_unsupported_opt_cxx_darwin_i386)
+            << Unsupported->getOption().getName();
+    }
+    // The faltivec option has been superseded by the maltivec option.
+    if ((Unsupported = Args.getLastArg(options::OPT_faltivec)))
+      D.Diag(diag::err_drv_clang_unsupported_opt_faltivec)
+          << Unsupported->getOption().getName()
+          << "please use -maltivec and include altivec.h explicitly";
+    if ((Unsupported = Args.getLastArg(options::OPT_fno_altivec)))
+      D.Diag(diag::err_drv_clang_unsupported_opt_faltivec)
+          << Unsupported->getOption().getName() << "please use -mno-altivec";
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_v);
+  Args.AddLastArg(CmdArgs, options::OPT_H);
+  if (D.CCPrintHeaders && !D.CCGenDiagnostics) {
+    CmdArgs.push_back("-header-include-file");
+    CmdArgs.push_back(D.CCPrintHeadersFilename ? D.CCPrintHeadersFilename
+                                               : "-");
+  }
+  Args.AddLastArg(CmdArgs, options::OPT_P);
+  Args.AddLastArg(CmdArgs, options::OPT_print_ivar_layout);
+
+  if (D.CCLogDiagnostics && !D.CCGenDiagnostics) {
+    CmdArgs.push_back("-diagnostic-log-file");
+    CmdArgs.push_back(D.CCLogDiagnosticsFilename ? D.CCLogDiagnosticsFilename
+                                                 : "-");
+  }
+
+  bool splitDwarfInlining =
+      Args.hasFlag(options::OPT_fsplit_dwarf_inlining,
+                   options::OPT_fno_split_dwarf_inlining, true);
+
+  Args.ClaimAllArgs(options::OPT_g_Group);
+  Arg *SplitDwarfArg = Args.getLastArg(options::OPT_gsplit_dwarf);
+  if (Arg *A = Args.getLastArg(options::OPT_g_Group)) {
+    // If the last option explicitly specified a debug-info level, use it.
+    if (A->getOption().matches(options::OPT_gN_Group)) {
+      DebugInfoKind = DebugLevelToInfoKind(*A);
+      // If you say "-gsplit-dwarf -gline-tables-only", -gsplit-dwarf loses.
+      // But -gsplit-dwarf is not a g_group option, hence we have to check the
+      // order explicitly. (If -gsplit-dwarf wins, we fix DebugInfoKind later.)
+      // This gets a bit more complicated if you've disabled inline info in the
+      // skeleton CUs (splitDwarfInlining) - then there's value in composing
+      // split-dwarf and line-tables-only, so let those compose naturally in
+      // that case.
+      // And if you just turned off debug info, (-gsplit-dwarf -g0) - do that.
+      if (SplitDwarfArg) {
+        if (A->getIndex() > SplitDwarfArg->getIndex()) {
+          if (DebugInfoKind == codegenoptions::NoDebugInfo ||
+              (DebugInfoKind == codegenoptions::DebugLineTablesOnly &&
+               splitDwarfInlining))
+            SplitDwarfArg = nullptr;
+        } else if (splitDwarfInlining)
+          DebugInfoKind = codegenoptions::NoDebugInfo;
+      }
+    } else
+      // For any other 'g' option, use Limited.
+      DebugInfoKind = codegenoptions::LimitedDebugInfo;
+  }
+
+  // If a debugger tuning argument appeared, remember it.
+  if (Arg *A = Args.getLastArg(options::OPT_gTune_Group,
+                               options::OPT_ggdbN_Group)) {
+    if (A->getOption().matches(options::OPT_glldb))
+      DebuggerTuning = llvm::DebuggerKind::LLDB;
+    else if (A->getOption().matches(options::OPT_gsce))
+      DebuggerTuning = llvm::DebuggerKind::SCE;
+    else
+      DebuggerTuning = llvm::DebuggerKind::GDB;
+  }
+
+  // If a -gdwarf argument appeared, remember it.
+  if (Arg *A = Args.getLastArg(options::OPT_gdwarf_2, options::OPT_gdwarf_3,
+                               options::OPT_gdwarf_4, options::OPT_gdwarf_5))
+    DwarfVersion = DwarfVersionNum(A->getSpelling());
+
+  // Forward -gcodeview. EmitCodeView might have been set by CL-compatibility
+  // argument parsing.
+  if (Args.hasArg(options::OPT_gcodeview) || EmitCodeView) {
+    // DwarfVersion remains at 0 if no explicit choice was made.
+    CmdArgs.push_back("-gcodeview");
+  } else if (DwarfVersion == 0 &&
+             DebugInfoKind != codegenoptions::NoDebugInfo) {
+    DwarfVersion = getToolChain().GetDefaultDwarfVersion();
+  }
+
+  // We ignore flag -gstrict-dwarf for now.
+  // And we handle flag -grecord-gcc-switches later with DwarfDebugFlags.
+  Args.ClaimAllArgs(options::OPT_g_flags_Group);
+
+  // Column info is included by default for everything except PS4 and CodeView.
+  // Clang doesn't track end columns, just starting columns, which, in theory,
+  // is fine for CodeView (and PDB).  In practice, however, the Microsoft
+  // debuggers don't handle missing end columns well, so it's better not to
+  // include any column info.
+  if (Args.hasFlag(options::OPT_gcolumn_info, options::OPT_gno_column_info,
+                   /*Default=*/ !IsPS4CPU && !(IsWindowsMSVC && EmitCodeView)))
+    CmdArgs.push_back("-dwarf-column-info");
+
+  // FIXME: Move backend command line options to the module.
+  // If -gline-tables-only is the last option it wins.
+  if (DebugInfoKind != codegenoptions::DebugLineTablesOnly &&
+      Args.hasArg(options::OPT_gmodules)) {
+    DebugInfoKind = codegenoptions::LimitedDebugInfo;
+    CmdArgs.push_back("-dwarf-ext-refs");
+    CmdArgs.push_back("-fmodule-format=obj");
+  }
+
+  // -gsplit-dwarf should turn on -g and enable the backend dwarf
+  // splitting and extraction.
+  // FIXME: Currently only works on Linux.
+  if (getToolChain().getTriple().isOSLinux() && SplitDwarfArg) {
+    if (!splitDwarfInlining)
+      CmdArgs.push_back("-fno-split-dwarf-inlining");
+    if (DebugInfoKind == codegenoptions::NoDebugInfo)
+      DebugInfoKind = codegenoptions::LimitedDebugInfo;
+    CmdArgs.push_back("-backend-option");
+    CmdArgs.push_back("-split-dwarf=Enable");
+  }
+
+  // After we've dealt with all combinations of things that could
+  // make DebugInfoKind be other than None or DebugLineTablesOnly,
+  // figure out if we need to "upgrade" it to standalone debug info.
+  // We parse these two '-f' options whether or not they will be used,
+  // to claim them even if you wrote "-fstandalone-debug -gline-tables-only"
+  bool NeedFullDebug = Args.hasFlag(options::OPT_fstandalone_debug,
+                                    options::OPT_fno_standalone_debug,
+                                    getToolChain().GetDefaultStandaloneDebug());
+  if (DebugInfoKind == codegenoptions::LimitedDebugInfo && NeedFullDebug)
+    DebugInfoKind = codegenoptions::FullDebugInfo;
+  RenderDebugEnablingArgs(Args, CmdArgs, DebugInfoKind, DwarfVersion,
+                          DebuggerTuning);
+
+  // -fdebug-macro turns on macro debug info generation.
+  if (Args.hasFlag(options::OPT_fdebug_macro, options::OPT_fno_debug_macro,
+                   false))
+    CmdArgs.push_back("-debug-info-macro");
+
+  // -ggnu-pubnames turns on gnu style pubnames in the backend.
+  if (Args.hasArg(options::OPT_ggnu_pubnames)) {
+    CmdArgs.push_back("-backend-option");
+    CmdArgs.push_back("-generate-gnu-dwarf-pub-sections");
+  }
+
+  // -gdwarf-aranges turns on the emission of the aranges section in the
+  // backend.
+  // Always enabled on the PS4.
+  if (Args.hasArg(options::OPT_gdwarf_aranges) || IsPS4CPU) {
+    CmdArgs.push_back("-backend-option");
+    CmdArgs.push_back("-generate-arange-section");
+  }
+
+  if (Args.hasFlag(options::OPT_fdebug_types_section,
+                   options::OPT_fno_debug_types_section, false)) {
+    CmdArgs.push_back("-backend-option");
+    CmdArgs.push_back("-generate-type-units");
+  }
+
+  bool UseSeparateSections = isUseSeparateSections(Triple);
+
+  if (Args.hasFlag(options::OPT_ffunction_sections,
+                   options::OPT_fno_function_sections, UseSeparateSections)) {
+    CmdArgs.push_back("-ffunction-sections");
+  }
+
+  if (Args.hasFlag(options::OPT_fdata_sections, options::OPT_fno_data_sections,
+                   UseSeparateSections)) {
+    CmdArgs.push_back("-fdata-sections");
+  }
+
+  if (!Args.hasFlag(options::OPT_funique_section_names,
+                    options::OPT_fno_unique_section_names, true))
+    CmdArgs.push_back("-fno-unique-section-names");
+
+  Args.AddAllArgs(CmdArgs, options::OPT_finstrument_functions);
+
+  addPGOAndCoverageFlags(C, D, Output, Args, CmdArgs);
+
+  // Add runtime flag for PS4 when PGO or Coverage are enabled.
+  if (getToolChain().getTriple().isPS4CPU())
+    PS4cpu::addProfileRTArgs(getToolChain(), Args, CmdArgs);
+
+  // Pass options for controlling the default header search paths.
+  if (Args.hasArg(options::OPT_nostdinc)) {
+    CmdArgs.push_back("-nostdsysteminc");
+    CmdArgs.push_back("-nobuiltininc");
+  } else {
+    if (Args.hasArg(options::OPT_nostdlibinc))
+      CmdArgs.push_back("-nostdsysteminc");
+    Args.AddLastArg(CmdArgs, options::OPT_nostdincxx);
+    Args.AddLastArg(CmdArgs, options::OPT_nobuiltininc);
+  }
+
+  // Pass the path to compiler resource files.
+  CmdArgs.push_back("-resource-dir");
+  CmdArgs.push_back(D.ResourceDir.c_str());
+
+  Args.AddLastArg(CmdArgs, options::OPT_working_directory);
+
+  bool ARCMTEnabled = false;
+  if (!Args.hasArg(options::OPT_fno_objc_arc, options::OPT_fobjc_arc)) {
+    if (const Arg *A = Args.getLastArg(options::OPT_ccc_arcmt_check,
+                                       options::OPT_ccc_arcmt_modify,
+                                       options::OPT_ccc_arcmt_migrate)) {
+      ARCMTEnabled = true;
+      switch (A->getOption().getID()) {
+      default:
+        llvm_unreachable("missed a case");
+      case options::OPT_ccc_arcmt_check:
+        CmdArgs.push_back("-arcmt-check");
+        break;
+      case options::OPT_ccc_arcmt_modify:
+        CmdArgs.push_back("-arcmt-modify");
+        break;
+      case options::OPT_ccc_arcmt_migrate:
+        CmdArgs.push_back("-arcmt-migrate");
+        CmdArgs.push_back("-mt-migrate-directory");
+        CmdArgs.push_back(A->getValue());
+
+        Args.AddLastArg(CmdArgs, options::OPT_arcmt_migrate_report_output);
+        Args.AddLastArg(CmdArgs, options::OPT_arcmt_migrate_emit_arc_errors);
+        break;
+      }
+    }
+  } else {
+    Args.ClaimAllArgs(options::OPT_ccc_arcmt_check);
+    Args.ClaimAllArgs(options::OPT_ccc_arcmt_modify);
+    Args.ClaimAllArgs(options::OPT_ccc_arcmt_migrate);
+  }
+
+  if (const Arg *A = Args.getLastArg(options::OPT_ccc_objcmt_migrate)) {
+    if (ARCMTEnabled) {
+      D.Diag(diag::err_drv_argument_not_allowed_with) << A->getAsString(Args)
+                                                      << "-ccc-arcmt-migrate";
+    }
+    CmdArgs.push_back("-mt-migrate-directory");
+    CmdArgs.push_back(A->getValue());
+
+    if (!Args.hasArg(options::OPT_objcmt_migrate_literals,
+                     options::OPT_objcmt_migrate_subscripting,
+                     options::OPT_objcmt_migrate_property)) {
+      // None specified, means enable them all.
+      CmdArgs.push_back("-objcmt-migrate-literals");
+      CmdArgs.push_back("-objcmt-migrate-subscripting");
+      CmdArgs.push_back("-objcmt-migrate-property");
+    } else {
+      Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_literals);
+      Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_subscripting);
+      Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_property);
+    }
+  } else {
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_literals);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_subscripting);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_property);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_all);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_readonly_property);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_readwrite_property);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_property_dot_syntax);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_annotation);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_instancetype);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_nsmacros);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_protocol_conformance);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_atomic_property);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_returns_innerpointer_property);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_ns_nonatomic_iosonly);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_migrate_designated_init);
+    Args.AddLastArg(CmdArgs, options::OPT_objcmt_whitelist_dir_path);
+  }
+
+  // Add preprocessing options like -I, -D, etc. if we are using the
+  // preprocessor.
+  //
+  // FIXME: Support -fpreprocessed
+  if (types::getPreprocessedType(InputType) != types::TY_INVALID)
+    AddPreprocessingOptions(C, JA, D, Args, CmdArgs, Output, Inputs);
+
+  // Don't warn about "clang -c -DPIC -fPIC test.i" because libtool.m4 assumes
+  // that "The compiler can only warn and ignore the option if not recognized".
+  // When building with ccache, it will pass -D options to clang even on
+  // preprocessed inputs and configure concludes that -fPIC is not supported.
+  Args.ClaimAllArgs(options::OPT_D);
+
+  // Manually translate -O4 to -O3; let clang reject others.
+  if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
+    if (A->getOption().matches(options::OPT_O4)) {
+      CmdArgs.push_back("-O3");
+      D.Diag(diag::warn_O4_is_O3);
+    } else {
+      A->render(Args, CmdArgs);
+    }
+  }
+
+  // Warn about ignored options to clang.
+  for (const Arg *A :
+       Args.filtered(options::OPT_clang_ignored_gcc_optimization_f_Group)) {
+    D.Diag(diag::warn_ignored_gcc_optimization) << A->getAsString(Args);
+    A->claim();
+  }
+
+  claimNoWarnArgs(Args);
+
+  Args.AddAllArgs(CmdArgs, options::OPT_R_Group);
+
+  Args.AddAllArgs(CmdArgs, options::OPT_W_Group);
+  if (Args.hasFlag(options::OPT_pedantic, options::OPT_no_pedantic, false))
+    CmdArgs.push_back("-pedantic");
+  Args.AddLastArg(CmdArgs, options::OPT_pedantic_errors);
+  Args.AddLastArg(CmdArgs, options::OPT_w);
+
+  // Handle -{std, ansi, trigraphs} -- take the last of -{std, ansi}
+  // (-ansi is equivalent to -std=c89 or -std=c++98).
+  //
+  // If a std is supplied, only add -trigraphs if it follows the
+  // option.
+  bool ImplyVCPPCXXVer = false;
+  if (Arg *Std = Args.getLastArg(options::OPT_std_EQ, options::OPT_ansi)) {
+    if (Std->getOption().matches(options::OPT_ansi))
+      if (types::isCXX(InputType))
+        CmdArgs.push_back("-std=c++98");
+      else
+        CmdArgs.push_back("-std=c89");
+    else
+      Std->render(Args, CmdArgs);
+
+    // If -f(no-)trigraphs appears after the language standard flag, honor it.
+    if (Arg *A = Args.getLastArg(options::OPT_std_EQ, options::OPT_ansi,
+                                 options::OPT_ftrigraphs,
+                                 options::OPT_fno_trigraphs))
+      if (A != Std)
+        A->render(Args, CmdArgs);
+  } else {
+    // Honor -std-default.
+    //
+    // FIXME: Clang doesn't correctly handle -std= when the input language
+    // doesn't match. For the time being just ignore this for C++ inputs;
+    // eventually we want to do all the standard defaulting here instead of
+    // splitting it between the driver and clang -cc1.
+    if (!types::isCXX(InputType))
+      Args.AddAllArgsTranslated(CmdArgs, options::OPT_std_default_EQ, "-std=",
+                                /*Joined=*/true);
+    else if (IsWindowsMSVC)
+      ImplyVCPPCXXVer = true;
+
+    Args.AddLastArg(CmdArgs, options::OPT_ftrigraphs,
+                    options::OPT_fno_trigraphs);
+  }
+
+  // GCC's behavior for -Wwrite-strings is a bit strange:
+  //  * In C, this "warning flag" changes the types of string literals from
+  //    'char[N]' to 'const char[N]', and thus triggers an unrelated warning
+  //    for the discarded qualifier.
+  //  * In C++, this is just a normal warning flag.
+  //
+  // Implementing this warning correctly in C is hard, so we follow GCC's
+  // behavior for now. FIXME: Directly diagnose uses of a string literal as
+  // a non-const char* in C, rather than using this crude hack.
+  if (!types::isCXX(InputType)) {
+    // FIXME: This should behave just like a warning flag, and thus should also
+    // respect -Weverything, -Wno-everything, -Werror=write-strings, and so on.
+    Arg *WriteStrings =
+        Args.getLastArg(options::OPT_Wwrite_strings,
+                        options::OPT_Wno_write_strings, options::OPT_w);
+    if (WriteStrings &&
+        WriteStrings->getOption().matches(options::OPT_Wwrite_strings))
+      CmdArgs.push_back("-fconst-strings");
+  }
+
+  // GCC provides a macro definition '__DEPRECATED' when -Wdeprecated is active
+  // during C++ compilation, which it is by default. GCC keeps this define even
+  // in the presence of '-w', match this behavior bug-for-bug.
+  if (types::isCXX(InputType) &&
+      Args.hasFlag(options::OPT_Wdeprecated, options::OPT_Wno_deprecated,
+                   true)) {
+    CmdArgs.push_back("-fdeprecated-macro");
+  }
+
+  // Translate GCC's misnamer '-fasm' arguments to '-fgnu-keywords'.
+  if (Arg *Asm = Args.getLastArg(options::OPT_fasm, options::OPT_fno_asm)) {
+    if (Asm->getOption().matches(options::OPT_fasm))
+      CmdArgs.push_back("-fgnu-keywords");
+    else
+      CmdArgs.push_back("-fno-gnu-keywords");
+  }
+
+  if (ShouldDisableDwarfDirectory(Args, getToolChain()))
+    CmdArgs.push_back("-fno-dwarf-directory-asm");
+
+  if (ShouldDisableAutolink(Args, getToolChain()))
+    CmdArgs.push_back("-fno-autolink");
+
+  // Add in -fdebug-compilation-dir if necessary.
+  addDebugCompDirArg(Args, CmdArgs);
+
+  for (const Arg *A : Args.filtered(options::OPT_fdebug_prefix_map_EQ)) {
+    StringRef Map = A->getValue();
+    if (Map.find('=') == StringRef::npos)
+      D.Diag(diag::err_drv_invalid_argument_to_fdebug_prefix_map) << Map;
+    else
+      CmdArgs.push_back(Args.MakeArgString("-fdebug-prefix-map=" + Map));
+    A->claim();
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_ftemplate_depth_,
+                               options::OPT_ftemplate_depth_EQ)) {
+    CmdArgs.push_back("-ftemplate-depth");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_foperator_arrow_depth_EQ)) {
+    CmdArgs.push_back("-foperator-arrow-depth");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_fconstexpr_depth_EQ)) {
+    CmdArgs.push_back("-fconstexpr-depth");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_fconstexpr_steps_EQ)) {
+    CmdArgs.push_back("-fconstexpr-steps");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_fbracket_depth_EQ)) {
+    CmdArgs.push_back("-fbracket-depth");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_Wlarge_by_value_copy_EQ,
+                               options::OPT_Wlarge_by_value_copy_def)) {
+    if (A->getNumValues()) {
+      StringRef bytes = A->getValue();
+      CmdArgs.push_back(Args.MakeArgString("-Wlarge-by-value-copy=" + bytes));
+    } else
+      CmdArgs.push_back("-Wlarge-by-value-copy=64"); // default value
+  }
+
+  if (Args.hasArg(options::OPT_relocatable_pch))
+    CmdArgs.push_back("-relocatable-pch");
+
+  if (Arg *A = Args.getLastArg(options::OPT_fconstant_string_class_EQ)) {
+    CmdArgs.push_back("-fconstant-string-class");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_ftabstop_EQ)) {
+    CmdArgs.push_back("-ftabstop");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  CmdArgs.push_back("-ferror-limit");
+  if (Arg *A = Args.getLastArg(options::OPT_ferror_limit_EQ))
+    CmdArgs.push_back(A->getValue());
+  else
+    CmdArgs.push_back("19");
+
+  if (Arg *A = Args.getLastArg(options::OPT_fmacro_backtrace_limit_EQ)) {
+    CmdArgs.push_back("-fmacro-backtrace-limit");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_ftemplate_backtrace_limit_EQ)) {
+    CmdArgs.push_back("-ftemplate-backtrace-limit");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_fconstexpr_backtrace_limit_EQ)) {
+    CmdArgs.push_back("-fconstexpr-backtrace-limit");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_fspell_checking_limit_EQ)) {
+    CmdArgs.push_back("-fspell-checking-limit");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  // Pass -fmessage-length=.
+  CmdArgs.push_back("-fmessage-length");
+  if (Arg *A = Args.getLastArg(options::OPT_fmessage_length_EQ)) {
+    CmdArgs.push_back(A->getValue());
+  } else {
+    // If -fmessage-length=N was not specified, determine whether this is a
+    // terminal and, if so, implicitly define -fmessage-length appropriately.
+    unsigned N = llvm::sys::Process::StandardErrColumns();
+    CmdArgs.push_back(Args.MakeArgString(Twine(N)));
+  }
+
+  // -fvisibility= and -fvisibility-ms-compat are of a piece.
+  if (const Arg *A = Args.getLastArg(options::OPT_fvisibility_EQ,
+                                     options::OPT_fvisibility_ms_compat)) {
+    if (A->getOption().matches(options::OPT_fvisibility_EQ)) {
+      CmdArgs.push_back("-fvisibility");
+      CmdArgs.push_back(A->getValue());
+    } else {
+      assert(A->getOption().matches(options::OPT_fvisibility_ms_compat));
+      CmdArgs.push_back("-fvisibility");
+      CmdArgs.push_back("hidden");
+      CmdArgs.push_back("-ftype-visibility");
+      CmdArgs.push_back("default");
+    }
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_fvisibility_inlines_hidden);
+
+  Args.AddLastArg(CmdArgs, options::OPT_ftlsmodel_EQ);
+
+  // -fhosted is default.
+  bool IsHosted = true;
+  if (Args.hasFlag(options::OPT_ffreestanding, options::OPT_fhosted, false) ||
+      KernelOrKext) {
+    CmdArgs.push_back("-ffreestanding");
+    IsHosted = false;
+  }
+
+  // Forward -f (flag) options which we can pass directly.
+  Args.AddLastArg(CmdArgs, options::OPT_femit_all_decls);
+  Args.AddLastArg(CmdArgs, options::OPT_fheinous_gnu_extensions);
+  Args.AddLastArg(CmdArgs, options::OPT_fno_operator_names);
+  // Emulated TLS is enabled by default on Android, and can be enabled manually
+  // with -femulated-tls.
+  bool EmulatedTLSDefault = Triple.isAndroid() || Triple.isWindowsCygwinEnvironment();
+  if (Args.hasFlag(options::OPT_femulated_tls, options::OPT_fno_emulated_tls,
+                   EmulatedTLSDefault))
+    CmdArgs.push_back("-femulated-tls");
+  // AltiVec-like language extensions aren't relevant for assembling.
+  if (!isa<PreprocessJobAction>(JA) || Output.getType() != types::TY_PP_Asm)
+    Args.AddLastArg(CmdArgs, options::OPT_fzvector);
+
+  Args.AddLastArg(CmdArgs, options::OPT_fdiagnostics_show_template_tree);
+  Args.AddLastArg(CmdArgs, options::OPT_fno_elide_type);
+
+  // Forward flags for OpenMP. We don't do this if the current action is an
+  // device offloading action other than OpenMP.
+  if (Args.hasFlag(options::OPT_fopenmp, options::OPT_fopenmp_EQ,
+                   options::OPT_fno_openmp, false) &&
+      (JA.isDeviceOffloading(Action::OFK_None) ||
+       JA.isDeviceOffloading(Action::OFK_OpenMP))) {
+    switch (getToolChain().getDriver().getOpenMPRuntime(Args)) {
+    case Driver::OMPRT_OMP:
+    case Driver::OMPRT_IOMP5:
+      // Clang can generate useful OpenMP code for these two runtime libraries.
+      CmdArgs.push_back("-fopenmp");
+
+      // If no option regarding the use of TLS in OpenMP codegeneration is
+      // given, decide a default based on the target. Otherwise rely on the
+      // options and pass the right information to the frontend.
+      if (!Args.hasFlag(options::OPT_fopenmp_use_tls,
+                        options::OPT_fnoopenmp_use_tls, /*Default=*/true))
+        CmdArgs.push_back("-fnoopenmp-use-tls");
+      Args.AddAllArgs(CmdArgs, options::OPT_fopenmp_version_EQ);
+      break;
+    default:
+      // By default, if Clang doesn't know how to generate useful OpenMP code
+      // for a specific runtime library, we just don't pass the '-fopenmp' flag
+      // down to the actual compilation.
+      // FIXME: It would be better to have a mode which *only* omits IR
+      // generation based on the OpenMP support so that we get consistent
+      // semantic analysis, etc.
+      break;
+    }
+  }
+
+  const SanitizerArgs &Sanitize = getToolChain().getSanitizerArgs();
+  Sanitize.addArgs(getToolChain(), Args, CmdArgs, InputType);
+
+  const XRayArgs &XRay = getToolChain().getXRayArgs();
+  XRay.addArgs(getToolChain(), Args, CmdArgs, InputType);
+
+  if (getToolChain().SupportsProfiling())
+    Args.AddLastArg(CmdArgs, options::OPT_pg);
+
+  if (getToolChain().SupportsProfiling())
+    Args.AddLastArg(CmdArgs, options::OPT_mfentry);
+
+  // -flax-vector-conversions is default.
+  if (!Args.hasFlag(options::OPT_flax_vector_conversions,
+                    options::OPT_fno_lax_vector_conversions))
+    CmdArgs.push_back("-fno-lax-vector-conversions");
+
+  if (Args.getLastArg(options::OPT_fapple_kext) ||
+      (Args.hasArg(options::OPT_mkernel) && types::isCXX(InputType)))
+    CmdArgs.push_back("-fapple-kext");
+
+  Args.AddLastArg(CmdArgs, options::OPT_fobjc_sender_dependent_dispatch);
+  Args.AddLastArg(CmdArgs, options::OPT_fdiagnostics_print_source_range_info);
+  Args.AddLastArg(CmdArgs, options::OPT_fdiagnostics_parseable_fixits);
+  Args.AddLastArg(CmdArgs, options::OPT_ftime_report);
+  Args.AddLastArg(CmdArgs, options::OPT_ftrapv);
+
+  if (Arg *A = Args.getLastArg(options::OPT_ftrapv_handler_EQ)) {
+    CmdArgs.push_back("-ftrapv-handler");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_ftrap_function_EQ);
+
+  // -fno-strict-overflow implies -fwrapv if it isn't disabled, but
+  // -fstrict-overflow won't turn off an explicitly enabled -fwrapv.
+  if (Arg *A = Args.getLastArg(options::OPT_fwrapv, options::OPT_fno_wrapv)) {
+    if (A->getOption().matches(options::OPT_fwrapv))
+      CmdArgs.push_back("-fwrapv");
+  } else if (Arg *A = Args.getLastArg(options::OPT_fstrict_overflow,
+                                      options::OPT_fno_strict_overflow)) {
+    if (A->getOption().matches(options::OPT_fno_strict_overflow))
+      CmdArgs.push_back("-fwrapv");
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_freroll_loops,
+                               options::OPT_fno_reroll_loops))
+    if (A->getOption().matches(options::OPT_freroll_loops))
+      CmdArgs.push_back("-freroll-loops");
+
+  Args.AddLastArg(CmdArgs, options::OPT_fwritable_strings);
+  Args.AddLastArg(CmdArgs, options::OPT_funroll_loops,
+                  options::OPT_fno_unroll_loops);
+
+  Args.AddLastArg(CmdArgs, options::OPT_pthread);
+
+  // -stack-protector=0 is default.
+  unsigned StackProtectorLevel = 0;
+  // NVPTX doesn't support stack protectors; from the compiler's perspective, it
+  // doesn't even have a stack!
+  if (!Triple.isNVPTX()) {
+    if (Arg *A = Args.getLastArg(options::OPT_fno_stack_protector,
+                                 options::OPT_fstack_protector_all,
+                                 options::OPT_fstack_protector_strong,
+                                 options::OPT_fstack_protector)) {
+      if (A->getOption().matches(options::OPT_fstack_protector)) {
+        StackProtectorLevel = std::max<unsigned>(
+            LangOptions::SSPOn,
+            getToolChain().GetDefaultStackProtectorLevel(KernelOrKext));
+      } else if (A->getOption().matches(options::OPT_fstack_protector_strong))
+        StackProtectorLevel = LangOptions::SSPStrong;
+      else if (A->getOption().matches(options::OPT_fstack_protector_all))
+        StackProtectorLevel = LangOptions::SSPReq;
+    } else {
+      StackProtectorLevel =
+          getToolChain().GetDefaultStackProtectorLevel(KernelOrKext);
+      // Only use a default stack protector on Darwin in case -ffreestanding
+      // is not specified.
+      if (Triple.isOSDarwin() && !IsHosted)
+        StackProtectorLevel = 0;
+    }
+  }
+  if (StackProtectorLevel) {
+    CmdArgs.push_back("-stack-protector");
+    CmdArgs.push_back(Args.MakeArgString(Twine(StackProtectorLevel)));
+  }
+
+  // --param ssp-buffer-size=
+  for (const Arg *A : Args.filtered(options::OPT__param)) {
+    StringRef Str(A->getValue());
+    if (Str.startswith("ssp-buffer-size=")) {
+      if (StackProtectorLevel) {
+        CmdArgs.push_back("-stack-protector-buffer-size");
+        // FIXME: Verify the argument is a valid integer.
+        CmdArgs.push_back(Args.MakeArgString(Str.drop_front(16)));
+      }
+      A->claim();
+    }
+  }
+
+  // Translate -mstackrealign
+  if (Args.hasFlag(options::OPT_mstackrealign, options::OPT_mno_stackrealign,
+                   false))
+    CmdArgs.push_back(Args.MakeArgString("-mstackrealign"));
+
+  if (Args.hasArg(options::OPT_mstack_alignment)) {
+    StringRef alignment = Args.getLastArgValue(options::OPT_mstack_alignment);
+    CmdArgs.push_back(Args.MakeArgString("-mstack-alignment=" + alignment));
+  }
+
+  if (Args.hasArg(options::OPT_mstack_probe_size)) {
+    StringRef Size = Args.getLastArgValue(options::OPT_mstack_probe_size);
+
+    if (!Size.empty())
+      CmdArgs.push_back(Args.MakeArgString("-mstack-probe-size=" + Size));
+    else
+      CmdArgs.push_back("-mstack-probe-size=0");
+  }
+
+  switch (getToolChain().getArch()) {
+  case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_be:
+  case llvm::Triple::arm:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumb:
+  case llvm::Triple::thumbeb:
+    CmdArgs.push_back("-fallow-half-arguments-and-returns");
+    break;
+
+  default:
+    break;
+  }
+
+  if (Arg *A = Args.getLastArg(options::OPT_mrestrict_it,
+                               options::OPT_mno_restrict_it)) {
+    if (A->getOption().matches(options::OPT_mrestrict_it)) {
+      CmdArgs.push_back("-backend-option");
+      CmdArgs.push_back("-arm-restrict-it");
+    } else {
+      CmdArgs.push_back("-backend-option");
+      CmdArgs.push_back("-arm-no-restrict-it");
+    }
+  } else if (Triple.isOSWindows() &&
+             (Triple.getArch() == llvm::Triple::arm ||
+              Triple.getArch() == llvm::Triple::thumb)) {
+    // Windows on ARM expects restricted IT blocks
+    CmdArgs.push_back("-backend-option");
+    CmdArgs.push_back("-arm-restrict-it");
+  }
+
+  // Forward -cl options to -cc1
+  if (Args.getLastArg(options::OPT_cl_opt_disable)) {
+    CmdArgs.push_back("-cl-opt-disable");
+  }
+  if (Args.getLastArg(options::OPT_cl_strict_aliasing)) {
+    CmdArgs.push_back("-cl-strict-aliasing");
+  }
+  if (Args.getLastArg(options::OPT_cl_single_precision_constant)) {
+    CmdArgs.push_back("-cl-single-precision-constant");
+  }
+  if (Args.getLastArg(options::OPT_cl_finite_math_only)) {
+    CmdArgs.push_back("-cl-finite-math-only");
+  }
+  if (Args.getLastArg(options::OPT_cl_kernel_arg_info)) {
+    CmdArgs.push_back("-cl-kernel-arg-info");
+  }
+  if (Args.getLastArg(options::OPT_cl_unsafe_math_optimizations)) {
+    CmdArgs.push_back("-cl-unsafe-math-optimizations");
+  }
+  if (Args.getLastArg(options::OPT_cl_fast_relaxed_math)) {
+    CmdArgs.push_back("-cl-fast-relaxed-math");
+  }
+  if (Args.getLastArg(options::OPT_cl_mad_enable)) {
+    CmdArgs.push_back("-cl-mad-enable");
+  }
+  if (Args.getLastArg(options::OPT_cl_no_signed_zeros)) {
+    CmdArgs.push_back("-cl-no-signed-zeros");
+  }
+  if (Arg *A = Args.getLastArg(options::OPT_cl_std_EQ)) {
+    std::string CLStdStr = "-cl-std=";
+    CLStdStr += A->getValue();
+    CmdArgs.push_back(Args.MakeArgString(CLStdStr));
+  }
+  if (Args.getLastArg(options::OPT_cl_denorms_are_zero)) {
+    CmdArgs.push_back("-cl-denorms-are-zero");
+  }
+  if (Args.getLastArg(options::OPT_cl_fp32_correctly_rounded_divide_sqrt)) {
+    CmdArgs.push_back("-cl-fp32-correctly-rounded-divide-sqrt");
+  }
+
+  // Forward -f options with positive and negative forms; we translate
+  // these by hand.
+  if (Arg *A = getLastProfileSampleUseArg(Args)) {
+    StringRef fname = A->getValue();
+    if (!llvm::sys::fs::exists(fname))
+      D.Diag(diag::err_drv_no_such_file) << fname;
+    else
+      A->render(Args, CmdArgs);
+  }
+
+  if (Args.hasFlag(options::OPT_fdebug_info_for_profiling,
+                   options::OPT_fno_debug_info_for_profiling, false))
+    CmdArgs.push_back("-fdebug-info-for-profiling");
+
+  // -fbuiltin is default unless -mkernel is used.
+  bool UseBuiltins =
+      Args.hasFlag(options::OPT_fbuiltin, options::OPT_fno_builtin,
+                   !Args.hasArg(options::OPT_mkernel));
+  if (!UseBuiltins)
+    CmdArgs.push_back("-fno-builtin");
+
+  // -ffreestanding implies -fno-builtin.
+  if (Args.hasArg(options::OPT_ffreestanding))
+    UseBuiltins = false;
+
+  // Process the -fno-builtin-* options.
+  for (const auto &Arg : Args) {
+    const Option &O = Arg->getOption();
+    if (!O.matches(options::OPT_fno_builtin_))
+      continue;
+
+    Arg->claim();
+    // If -fno-builtin is specified, then there's no need to pass the option to
+    // the frontend.
+    if (!UseBuiltins)
+      continue;
+
+    StringRef FuncName = Arg->getValue();
+    CmdArgs.push_back(Args.MakeArgString("-fno-builtin-" + FuncName));
+  }
+
+  if (!Args.hasFlag(options::OPT_fassume_sane_operator_new,
+                    options::OPT_fno_assume_sane_operator_new))
+    CmdArgs.push_back("-fno-assume-sane-operator-new");
+
+  // -fblocks=0 is default.
+  if (Args.hasFlag(options::OPT_fblocks, options::OPT_fno_blocks,
+                   getToolChain().IsBlocksDefault()) ||
+      (Args.hasArg(options::OPT_fgnu_runtime) &&
+       Args.hasArg(options::OPT_fobjc_nonfragile_abi) &&
+       !Args.hasArg(options::OPT_fno_blocks))) {
+    CmdArgs.push_back("-fblocks");
+
+    if (!Args.hasArg(options::OPT_fgnu_runtime) &&
+        !getToolChain().hasBlocksRuntime())
+      CmdArgs.push_back("-fblocks-runtime-optional");
+  }
+
+  if (Args.hasFlag(options::OPT_fcoroutines_ts, options::OPT_fno_coroutines_ts,
+                   false) &&
+      types::isCXX(InputType)) {
+    CmdArgs.push_back("-fcoroutines-ts");
+  }
+
+  // -fmodules enables the use of precompiled modules (off by default).
+  // Users can pass -fno-cxx-modules to turn off modules support for
+  // C++/Objective-C++ programs.
+  bool HaveClangModules = false;
+  if (Args.hasFlag(options::OPT_fmodules, options::OPT_fno_modules, false)) {
+    bool AllowedInCXX = Args.hasFlag(options::OPT_fcxx_modules,
+                                     options::OPT_fno_cxx_modules, true);
+    if (AllowedInCXX || !types::isCXX(InputType)) {
+      CmdArgs.push_back("-fmodules");
+      HaveClangModules = true;
+    }
+  }
+
+  bool HaveAnyModules = HaveClangModules;
+  if (Args.hasArg(options::OPT_fmodules_ts)) {
+    CmdArgs.push_back("-fmodules-ts");
+    HaveAnyModules = true;
+  }
+
+  // -fmodule-maps enables implicit reading of module map files. By default,
+  // this is enabled if we are using Clang's flavor of precompiled modules.
+  if (Args.hasFlag(options::OPT_fimplicit_module_maps,
+                   options::OPT_fno_implicit_module_maps, HaveClangModules)) {
+    CmdArgs.push_back("-fimplicit-module-maps");
+  }
+
+  // -fmodules-decluse checks that modules used are declared so (off by
+  // default).
+  if (Args.hasFlag(options::OPT_fmodules_decluse,
+                   options::OPT_fno_modules_decluse, false)) {
+    CmdArgs.push_back("-fmodules-decluse");
+  }
+
+  // -fmodules-strict-decluse is like -fmodule-decluse, but also checks that
+  // all #included headers are part of modules.
+  if (Args.hasFlag(options::OPT_fmodules_strict_decluse,
+                   options::OPT_fno_modules_strict_decluse, false)) {
+    CmdArgs.push_back("-fmodules-strict-decluse");
+  }
+
+  // -fno-implicit-modules turns off implicitly compiling modules on demand.
+  if (!Args.hasFlag(options::OPT_fimplicit_modules,
+                    options::OPT_fno_implicit_modules, HaveClangModules)) {
+    if (HaveAnyModules)
+      CmdArgs.push_back("-fno-implicit-modules");
+  } else if (HaveAnyModules) {
+    // -fmodule-cache-path specifies where our implicitly-built module files
+    // should be written.
+    SmallString<128> Path;
+    if (Arg *A = Args.getLastArg(options::OPT_fmodules_cache_path))
+      Path = A->getValue();
+    if (C.isForDiagnostics()) {
+      // When generating crash reports, we want to emit the modules along with
+      // the reproduction sources, so we ignore any provided module path.
+      Path = Output.getFilename();
+      llvm::sys::path::replace_extension(Path, ".cache");
+      llvm::sys::path::append(Path, "modules");
+    } else if (Path.empty()) {
+      // No module path was provided: use the default.
+      llvm::sys::path::system_temp_directory(/*erasedOnReboot=*/false, Path);
+      llvm::sys::path::append(Path, "org.llvm.clang.");
+      appendUserToPath(Path);
+      llvm::sys::path::append(Path, "ModuleCache");
+    }
+    const char Arg[] = "-fmodules-cache-path=";
+    Path.insert(Path.begin(), Arg, Arg + strlen(Arg));
+    CmdArgs.push_back(Args.MakeArgString(Path));
+  }
+
+  if (HaveAnyModules) {
+    // -fprebuilt-module-path specifies where to load the prebuilt module files.
+    for (const Arg *A : Args.filtered(options::OPT_fprebuilt_module_path))
+      CmdArgs.push_back(Args.MakeArgString(
+          std::string("-fprebuilt-module-path=") + A->getValue()));
+  }
+
+  // -fmodule-name specifies the module that is currently being built (or
+  // used for header checking by -fmodule-maps).
+  Args.AddLastArg(CmdArgs, options::OPT_fmodule_name_EQ);
+
+  // -fmodule-map-file can be used to specify files containing module
+  // definitions.
+  Args.AddAllArgs(CmdArgs, options::OPT_fmodule_map_file);
+
+  // -fbuiltin-module-map can be used to load the clang
+  // builtin headers modulemap file.
+  if (Args.hasArg(options::OPT_fbuiltin_module_map)) {
+    SmallString<128> BuiltinModuleMap(getToolChain().getDriver().ResourceDir);
+    llvm::sys::path::append(BuiltinModuleMap, "include");
+    llvm::sys::path::append(BuiltinModuleMap, "module.modulemap");
+    if (llvm::sys::fs::exists(BuiltinModuleMap)) {
+      CmdArgs.push_back(Args.MakeArgString("-fmodule-map-file=" +
+                                           BuiltinModuleMap));
+    }
+  }
+
+  // -fmodule-file can be used to specify files containing precompiled modules.
+  if (HaveAnyModules)
+    Args.AddAllArgs(CmdArgs, options::OPT_fmodule_file);
+  else
+    Args.ClaimAllArgs(options::OPT_fmodule_file);
+
+  // When building modules and generating crashdumps, we need to dump a module
+  // dependency VFS alongside the output.
+  if (HaveClangModules && C.isForDiagnostics()) {
+    SmallString<128> VFSDir(Output.getFilename());
+    llvm::sys::path::replace_extension(VFSDir, ".cache");
+    // Add the cache directory as a temp so the crash diagnostics pick it up.
+    C.addTempFile(Args.MakeArgString(VFSDir));
+
+    llvm::sys::path::append(VFSDir, "vfs");
+    CmdArgs.push_back("-module-dependency-dir");
+    CmdArgs.push_back(Args.MakeArgString(VFSDir));
+  }
+
+  if (HaveClangModules)
+    Args.AddLastArg(CmdArgs, options::OPT_fmodules_user_build_path);
+
+  // Pass through all -fmodules-ignore-macro arguments.
+  Args.AddAllArgs(CmdArgs, options::OPT_fmodules_ignore_macro);
+  Args.AddLastArg(CmdArgs, options::OPT_fmodules_prune_interval);
+  Args.AddLastArg(CmdArgs, options::OPT_fmodules_prune_after);
+
+  Args.AddLastArg(CmdArgs, options::OPT_fbuild_session_timestamp);
+
+  if (Arg *A = Args.getLastArg(options::OPT_fbuild_session_file)) {
+    if (Args.hasArg(options::OPT_fbuild_session_timestamp))
+      D.Diag(diag::err_drv_argument_not_allowed_with)
+          << A->getAsString(Args) << "-fbuild-session-timestamp";
+
+    llvm::sys::fs::file_status Status;
+    if (llvm::sys::fs::status(A->getValue(), Status))
+      D.Diag(diag::err_drv_no_such_file) << A->getValue();
+    CmdArgs.push_back(
+        Args.MakeArgString("-fbuild-session-timestamp=" +
+                           Twine((uint64_t)Status.getLastModificationTime()
+                                     .time_since_epoch()
+                                     .count())));
+  }
+
+  if (Args.getLastArg(options::OPT_fmodules_validate_once_per_build_session)) {
+    if (!Args.getLastArg(options::OPT_fbuild_session_timestamp,
+                         options::OPT_fbuild_session_file))
+      D.Diag(diag::err_drv_modules_validate_once_requires_timestamp);
+
+    Args.AddLastArg(CmdArgs,
+                    options::OPT_fmodules_validate_once_per_build_session);
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_fmodules_validate_system_headers);
+  Args.AddLastArg(CmdArgs, options::OPT_fmodules_disable_diagnostic_validation);
+
+  // -faccess-control is default.
+  if (Args.hasFlag(options::OPT_fno_access_control,
+                   options::OPT_faccess_control, false))
+    CmdArgs.push_back("-fno-access-control");
+
+  // -felide-constructors is the default.
+  if (Args.hasFlag(options::OPT_fno_elide_constructors,
+                   options::OPT_felide_constructors, false))
+    CmdArgs.push_back("-fno-elide-constructors");
+
+  ToolChain::RTTIMode RTTIMode = getToolChain().getRTTIMode();
+
+  if (KernelOrKext || (types::isCXX(InputType) &&
+                       (RTTIMode == ToolChain::RM_DisabledExplicitly ||
+                        RTTIMode == ToolChain::RM_DisabledImplicitly)))
+    CmdArgs.push_back("-fno-rtti");
+
+  // -fshort-enums=0 is default for all architectures except Hexagon.
+  if (Args.hasFlag(options::OPT_fshort_enums, options::OPT_fno_short_enums,
+                   getToolChain().getArch() == llvm::Triple::hexagon))
+    CmdArgs.push_back("-fshort-enums");
+
+  // -fsigned-char is default.
+  if (Arg *A = Args.getLastArg(
+          options::OPT_fsigned_char, options::OPT_fno_signed_char,
+          options::OPT_funsigned_char, options::OPT_fno_unsigned_char)) {
+    if (A->getOption().matches(options::OPT_funsigned_char) ||
+        A->getOption().matches(options::OPT_fno_signed_char)) {
+      CmdArgs.push_back("-fno-signed-char");
+    }
+  } else if (!isSignedCharDefault(getToolChain().getTriple())) {
+    CmdArgs.push_back("-fno-signed-char");
+  }
+
+  // -fuse-cxa-atexit is default.
+  if (!Args.hasFlag(
+          options::OPT_fuse_cxa_atexit, options::OPT_fno_use_cxa_atexit,
+          !IsWindowsCygnus && !IsWindowsGNU &&
+              getToolChain().getTriple().getOS() != llvm::Triple::Solaris &&
+              getToolChain().getArch() != llvm::Triple::hexagon &&
+              getToolChain().getArch() != llvm::Triple::xcore &&
+              ((getToolChain().getTriple().getVendor() !=
+                llvm::Triple::MipsTechnologies) ||
+               getToolChain().getTriple().hasEnvironment())) ||
+      KernelOrKext)
+    CmdArgs.push_back("-fno-use-cxa-atexit");
+
+  // -fms-extensions=0 is default.
+  if (Args.hasFlag(options::OPT_fms_extensions, options::OPT_fno_ms_extensions,
+                   IsWindowsMSVC))
+    CmdArgs.push_back("-fms-extensions");
+
+  // -fno-use-line-directives is default.
+  if (Args.hasFlag(options::OPT_fuse_line_directives,
+                   options::OPT_fno_use_line_directives, false))
+    CmdArgs.push_back("-fuse-line-directives");
+
+  // -fms-compatibility=0 is default.
+  if (Args.hasFlag(options::OPT_fms_compatibility,
+                   options::OPT_fno_ms_compatibility,
+                   (IsWindowsMSVC &&
+                    Args.hasFlag(options::OPT_fms_extensions,
+                                 options::OPT_fno_ms_extensions, true))))
+    CmdArgs.push_back("-fms-compatibility");
+
+  VersionTuple MSVT =
+      getToolChain().computeMSVCVersion(&getToolChain().getDriver(), Args);
+  if (!MSVT.empty())
+    CmdArgs.push_back(
+        Args.MakeArgString("-fms-compatibility-version=" + MSVT.getAsString()));
+
+  bool IsMSVC2015Compatible = MSVT.getMajor() >= 19;
+  if (ImplyVCPPCXXVer) {
+    StringRef LanguageStandard;
+    if (const Arg *StdArg = Args.getLastArg(options::OPT__SLASH_std)) {
+      LanguageStandard = llvm::StringSwitch<StringRef>(StdArg->getValue())
+                             .Case("c++14", "-std=c++14")
+                             .Case("c++latest", "-std=c++1z")
+                             .Default("");
+      if (LanguageStandard.empty())
+        D.Diag(clang::diag::warn_drv_unused_argument)
+            << StdArg->getAsString(Args);
+    }
+
+    if (LanguageStandard.empty()) {
+      if (IsMSVC2015Compatible)
+        LanguageStandard = "-std=c++14";
+      else
+        LanguageStandard = "-std=c++11";
+    }
+
+    CmdArgs.push_back(LanguageStandard.data());
+  }
+
+  // -fno-borland-extensions is default.
+  if (Args.hasFlag(options::OPT_fborland_extensions,
+                   options::OPT_fno_borland_extensions, false))
+    CmdArgs.push_back("-fborland-extensions");
+
+  // -fno-declspec is default, except for PS4.
+  if (Args.hasFlag(options::OPT_fdeclspec, options::OPT_fno_declspec,
+                   getToolChain().getTriple().isPS4()))
+    CmdArgs.push_back("-fdeclspec");
+  else if (Args.hasArg(options::OPT_fno_declspec))
+    CmdArgs.push_back("-fno-declspec"); // Explicitly disabling __declspec.
+
+  // -fthreadsafe-static is default, except for MSVC compatibility versions less
+  // than 19.
+  if (!Args.hasFlag(options::OPT_fthreadsafe_statics,
+                    options::OPT_fno_threadsafe_statics,
+                    !IsWindowsMSVC || IsMSVC2015Compatible))
+    CmdArgs.push_back("-fno-threadsafe-statics");
+
+  // -fno-delayed-template-parsing is default, except for Windows where MSVC STL
+  // needs it.
+  if (Args.hasFlag(options::OPT_fdelayed_template_parsing,
+                   options::OPT_fno_delayed_template_parsing, IsWindowsMSVC))
+    CmdArgs.push_back("-fdelayed-template-parsing");
+
+  // -fgnu-keywords default varies depending on language; only pass if
+  // specified.
+  if (Arg *A = Args.getLastArg(options::OPT_fgnu_keywords,
+                               options::OPT_fno_gnu_keywords))
+    A->render(Args, CmdArgs);
+
+  if (Args.hasFlag(options::OPT_fgnu89_inline, options::OPT_fno_gnu89_inline,
+                   false))
+    CmdArgs.push_back("-fgnu89-inline");
+
+  if (Args.hasArg(options::OPT_fno_inline))
+    CmdArgs.push_back("-fno-inline");
+
+  if (Arg* InlineArg = Args.getLastArg(options::OPT_finline_functions,
+                                       options::OPT_finline_hint_functions,
+                                       options::OPT_fno_inline_functions))
+    InlineArg->render(Args, CmdArgs);
+
+  Args.AddLastArg(CmdArgs, options::OPT_fexperimental_new_pass_manager,
+                  options::OPT_fno_experimental_new_pass_manager);
+
+  ObjCRuntime objcRuntime = AddObjCRuntimeArgs(Args, CmdArgs, rewriteKind);
+
+  // -fobjc-dispatch-method is only relevant with the nonfragile-abi, and
+  // legacy is the default. Except for deployment target of 10.5,
+  // next runtime is always legacy dispatch and -fno-objc-legacy-dispatch
+  // gets ignored silently.
+  if (objcRuntime.isNonFragile()) {
+    if (!Args.hasFlag(options::OPT_fobjc_legacy_dispatch,
+                      options::OPT_fno_objc_legacy_dispatch,
+                      objcRuntime.isLegacyDispatchDefaultForArch(
+                          getToolChain().getArch()))) {
+      if (getToolChain().UseObjCMixedDispatch())
+        CmdArgs.push_back("-fobjc-dispatch-method=mixed");
+      else
+        CmdArgs.push_back("-fobjc-dispatch-method=non-legacy");
+    }
+  }
+
+  // When ObjectiveC legacy runtime is in effect on MacOSX,
+  // turn on the option to do Array/Dictionary subscripting
+  // by default.
+  if (getToolChain().getArch() == llvm::Triple::x86 &&
+      getToolChain().getTriple().isMacOSX() &&
+      !getToolChain().getTriple().isMacOSXVersionLT(10, 7) &&
+      objcRuntime.getKind() == ObjCRuntime::FragileMacOSX &&
+      objcRuntime.isNeXTFamily())
+    CmdArgs.push_back("-fobjc-subscripting-legacy-runtime");
+
+  // -fencode-extended-block-signature=1 is default.
+  if (getToolChain().IsEncodeExtendedBlockSignatureDefault()) {
+    CmdArgs.push_back("-fencode-extended-block-signature");
+  }
+
+  // Allow -fno-objc-arr to trump -fobjc-arr/-fobjc-arc.
+  // NOTE: This logic is duplicated in ToolChains.cpp.
+  bool ARC = isObjCAutoRefCount(Args);
+  if (ARC) {
+    getToolChain().CheckObjCARC();
+
+    CmdArgs.push_back("-fobjc-arc");
+
+    // FIXME: It seems like this entire block, and several around it should be
+    // wrapped in isObjC, but for now we just use it here as this is where it
+    // was being used previously.
+    if (types::isCXX(InputType) && types::isObjC(InputType)) {
+      if (getToolChain().GetCXXStdlibType(Args) == ToolChain::CST_Libcxx)
+        CmdArgs.push_back("-fobjc-arc-cxxlib=libc++");
+      else
+        CmdArgs.push_back("-fobjc-arc-cxxlib=libstdc++");
+    }
+
+    // Allow the user to enable full exceptions code emission.
+    // We define off for Objective-CC, on for Objective-C++.
+    if (Args.hasFlag(options::OPT_fobjc_arc_exceptions,
+                     options::OPT_fno_objc_arc_exceptions,
+                     /*default*/ types::isCXX(InputType)))
+      CmdArgs.push_back("-fobjc-arc-exceptions");
+  }
+
+  // Silence warning for full exception code emission options when explicitly
+  // set to use no ARC.
+  if (Args.hasArg(options::OPT_fno_objc_arc)) {
+    Args.ClaimAllArgs(options::OPT_fobjc_arc_exceptions);
+    Args.ClaimAllArgs(options::OPT_fno_objc_arc_exceptions);
+  }
+
+  // -fobjc-infer-related-result-type is the default, except in the Objective-C
+  // rewriter.
+  if (rewriteKind != RK_None)
+    CmdArgs.push_back("-fno-objc-infer-related-result-type");
+
+  // Pass down -fobjc-weak or -fno-objc-weak if present.
+  if (types::isObjC(InputType)) {
+    auto WeakArg = Args.getLastArg(options::OPT_fobjc_weak,
+                                   options::OPT_fno_objc_weak);
+    if (!WeakArg) {
+      // nothing to do
+    } else if (!objcRuntime.allowsWeak()) {
+      if (WeakArg->getOption().matches(options::OPT_fobjc_weak))
+        D.Diag(diag::err_objc_weak_unsupported);
+    } else {
+      WeakArg->render(Args, CmdArgs);
+    }
+  }
+
+  if (Args.hasFlag(options::OPT_fapplication_extension,
+                   options::OPT_fno_application_extension, false))
+    CmdArgs.push_back("-fapplication-extension");
+
+  // Handle GCC-style exception args.
+  if (!C.getDriver().IsCLMode())
+    addExceptionArgs(Args, InputType, getToolChain(), KernelOrKext, objcRuntime,
+                     CmdArgs);
+
+  if (Args.hasArg(options::OPT_fsjlj_exceptions) ||
+      getToolChain().UseSjLjExceptions(Args))
+    CmdArgs.push_back("-fsjlj-exceptions");
+
+  // C++ "sane" operator new.
+  if (!Args.hasFlag(options::OPT_fassume_sane_operator_new,
+                    options::OPT_fno_assume_sane_operator_new))
+    CmdArgs.push_back("-fno-assume-sane-operator-new");
+
+  // -frelaxed-template-template-args is off by default, as it is a severe
+  // breaking change until a corresponding change to template partial ordering
+  // is provided.
+  if (Args.hasFlag(options::OPT_frelaxed_template_template_args,
+                   options::OPT_fno_relaxed_template_template_args, false))
+    CmdArgs.push_back("-frelaxed-template-template-args");
+
+  // -fsized-deallocation is off by default, as it is an ABI-breaking change for
+  // most platforms.
+  if (Args.hasFlag(options::OPT_fsized_deallocation,
+                   options::OPT_fno_sized_deallocation, false))
+    CmdArgs.push_back("-fsized-deallocation");
+
+  // -faligned-allocation is on by default in C++17 onwards and otherwise off
+  // by default.
+  if (Arg *A = Args.getLastArg(options::OPT_faligned_allocation,
+                               options::OPT_fno_aligned_allocation,
+                               options::OPT_faligned_new_EQ)) {
+    if (A->getOption().matches(options::OPT_fno_aligned_allocation))
+      CmdArgs.push_back("-fno-aligned-allocation");
+    else
+      CmdArgs.push_back("-faligned-allocation");
+  }
+
+  // The default new alignment can be specified using a dedicated option or via
+  // a GCC-compatible option that also turns on aligned allocation.
+  if (Arg *A = Args.getLastArg(options::OPT_fnew_alignment_EQ,
+                               options::OPT_faligned_new_EQ))
+    CmdArgs.push_back(
+        Args.MakeArgString(Twine("-fnew-alignment=") + A->getValue()));
+
+  // -fconstant-cfstrings is default, and may be subject to argument translation
+  // on Darwin.
+  if (!Args.hasFlag(options::OPT_fconstant_cfstrings,
+                    options::OPT_fno_constant_cfstrings) ||
+      !Args.hasFlag(options::OPT_mconstant_cfstrings,
+                    options::OPT_mno_constant_cfstrings))
+    CmdArgs.push_back("-fno-constant-cfstrings");
+
+  // -fshort-wchar default varies depending on platform; only
+  // pass if specified.
+  if (Arg *A = Args.getLastArg(options::OPT_fshort_wchar,
+                               options::OPT_fno_short_wchar))
+    A->render(Args, CmdArgs);
+
+  // -fno-pascal-strings is default, only pass non-default.
+  if (Args.hasFlag(options::OPT_fpascal_strings,
+                   options::OPT_fno_pascal_strings, false))
+    CmdArgs.push_back("-fpascal-strings");
+
+  // Honor -fpack-struct= and -fpack-struct, if given. Note that
+  // -fno-pack-struct doesn't apply to -fpack-struct=.
+  if (Arg *A = Args.getLastArg(options::OPT_fpack_struct_EQ)) {
+    std::string PackStructStr = "-fpack-struct=";
+    PackStructStr += A->getValue();
+    CmdArgs.push_back(Args.MakeArgString(PackStructStr));
+  } else if (Args.hasFlag(options::OPT_fpack_struct,
+                          options::OPT_fno_pack_struct, false)) {
+    CmdArgs.push_back("-fpack-struct=1");
+  }
+
+  // Handle -fmax-type-align=N and -fno-type-align
+  bool SkipMaxTypeAlign = Args.hasArg(options::OPT_fno_max_type_align);
+  if (Arg *A = Args.getLastArg(options::OPT_fmax_type_align_EQ)) {
+    if (!SkipMaxTypeAlign) {
+      std::string MaxTypeAlignStr = "-fmax-type-align=";
+      MaxTypeAlignStr += A->getValue();
+      CmdArgs.push_back(Args.MakeArgString(MaxTypeAlignStr));
+    }
+  } else if (getToolChain().getTriple().isOSDarwin()) {
+    if (!SkipMaxTypeAlign) {
+      std::string MaxTypeAlignStr = "-fmax-type-align=16";
+      CmdArgs.push_back(Args.MakeArgString(MaxTypeAlignStr));
+    }
+  }
+
+  // -fcommon is the default unless compiling kernel code or the target says so
+  bool NoCommonDefault =
+      KernelOrKext || isNoCommonDefault(getToolChain().getTriple());
+  if (!Args.hasFlag(options::OPT_fcommon, options::OPT_fno_common,
+                    !NoCommonDefault))
+    CmdArgs.push_back("-fno-common");
+
+  // -fsigned-bitfields is default, and clang doesn't yet support
+  // -funsigned-bitfields.
+  if (!Args.hasFlag(options::OPT_fsigned_bitfields,
+                    options::OPT_funsigned_bitfields))
+    D.Diag(diag::warn_drv_clang_unsupported)
+        << Args.getLastArg(options::OPT_funsigned_bitfields)->getAsString(Args);
+
+  // -fsigned-bitfields is default, and clang doesn't support -fno-for-scope.
+  if (!Args.hasFlag(options::OPT_ffor_scope, options::OPT_fno_for_scope))
+    D.Diag(diag::err_drv_clang_unsupported)
+        << Args.getLastArg(options::OPT_fno_for_scope)->getAsString(Args);
+
+  // -finput_charset=UTF-8 is default. Reject others
+  if (Arg *inputCharset = Args.getLastArg(options::OPT_finput_charset_EQ)) {
+    StringRef value = inputCharset->getValue();
+    if (!value.equals_lower("utf-8"))
+      D.Diag(diag::err_drv_invalid_value) << inputCharset->getAsString(Args)
+                                          << value;
+  }
+
+  // -fexec_charset=UTF-8 is default. Reject others
+  if (Arg *execCharset = Args.getLastArg(options::OPT_fexec_charset_EQ)) {
+    StringRef value = execCharset->getValue();
+    if (!value.equals_lower("utf-8"))
+      D.Diag(diag::err_drv_invalid_value) << execCharset->getAsString(Args)
+                                          << value;
+  }
+
+  // -fcaret-diagnostics is default.
+  if (!Args.hasFlag(options::OPT_fcaret_diagnostics,
+                    options::OPT_fno_caret_diagnostics, true))
+    CmdArgs.push_back("-fno-caret-diagnostics");
+
+  // -fdiagnostics-fixit-info is default, only pass non-default.
+  if (!Args.hasFlag(options::OPT_fdiagnostics_fixit_info,
+                    options::OPT_fno_diagnostics_fixit_info))
+    CmdArgs.push_back("-fno-diagnostics-fixit-info");
+
+  // Enable -fdiagnostics-show-option by default.
+  if (Args.hasFlag(options::OPT_fdiagnostics_show_option,
+                   options::OPT_fno_diagnostics_show_option))
+    CmdArgs.push_back("-fdiagnostics-show-option");
+
+  if (const Arg *A =
+          Args.getLastArg(options::OPT_fdiagnostics_show_category_EQ)) {
+    CmdArgs.push_back("-fdiagnostics-show-category");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  if (Args.hasFlag(options::OPT_fdiagnostics_show_hotness,
+                   options::OPT_fno_diagnostics_show_hotness, false))
+    CmdArgs.push_back("-fdiagnostics-show-hotness");
+
+  if (const Arg *A = Args.getLastArg(options::OPT_fdiagnostics_format_EQ)) {
+    CmdArgs.push_back("-fdiagnostics-format");
+    CmdArgs.push_back(A->getValue());
+  }
+
+  if (Arg *A = Args.getLastArg(
+          options::OPT_fdiagnostics_show_note_include_stack,
+          options::OPT_fno_diagnostics_show_note_include_stack)) {
+    if (A->getOption().matches(
+            options::OPT_fdiagnostics_show_note_include_stack))
+      CmdArgs.push_back("-fdiagnostics-show-note-include-stack");
+    else
+      CmdArgs.push_back("-fno-diagnostics-show-note-include-stack");
+  }
+
+  // Color diagnostics are parsed by the driver directly from argv
+  // and later re-parsed to construct this job; claim any possible
+  // color diagnostic here to avoid warn_drv_unused_argument and
+  // diagnose bad OPT_fdiagnostics_color_EQ values.
+  for (Arg *A : Args) {
+    const Option &O = A->getOption();
+    if (!O.matches(options::OPT_fcolor_diagnostics) &&
+        !O.matches(options::OPT_fdiagnostics_color) &&
+        !O.matches(options::OPT_fno_color_diagnostics) &&
+        !O.matches(options::OPT_fno_diagnostics_color) &&
+        !O.matches(options::OPT_fdiagnostics_color_EQ))
+      continue;
+    if (O.matches(options::OPT_fdiagnostics_color_EQ)) {
+      StringRef Value(A->getValue());
+      if (Value != "always" && Value != "never" && Value != "auto")
+        getToolChain().getDriver().Diag(diag::err_drv_clang_unsupported)
+              << ("-fdiagnostics-color=" + Value).str();
+    }
+    A->claim();
+  }
+  if (D.getDiags().getDiagnosticOptions().ShowColors)
+    CmdArgs.push_back("-fcolor-diagnostics");
+
+  if (Args.hasArg(options::OPT_fansi_escape_codes))
+    CmdArgs.push_back("-fansi-escape-codes");
+
+  if (!Args.hasFlag(options::OPT_fshow_source_location,
+                    options::OPT_fno_show_source_location))
+    CmdArgs.push_back("-fno-show-source-location");
+
+  if (Args.hasArg(options::OPT_fdiagnostics_absolute_paths))
+    CmdArgs.push_back("-fdiagnostics-absolute-paths");
+
+  if (!Args.hasFlag(options::OPT_fshow_column, options::OPT_fno_show_column,
+                    true))
+    CmdArgs.push_back("-fno-show-column");
+
+  if (!Args.hasFlag(options::OPT_fspell_checking,
+                    options::OPT_fno_spell_checking))
+    CmdArgs.push_back("-fno-spell-checking");
+
+  // -fno-asm-blocks is default.
+  if (Args.hasFlag(options::OPT_fasm_blocks, options::OPT_fno_asm_blocks,
+                   false))
+    CmdArgs.push_back("-fasm-blocks");
+
+  // -fgnu-inline-asm is default.
+  if (!Args.hasFlag(options::OPT_fgnu_inline_asm,
+                    options::OPT_fno_gnu_inline_asm, true))
+    CmdArgs.push_back("-fno-gnu-inline-asm");
+
+  // Enable vectorization per default according to the optimization level
+  // selected. For optimization levels that want vectorization we use the alias
+  // option to simplify the hasFlag logic.
+  bool EnableVec = shouldEnableVectorizerAtOLevel(Args, false);
+  OptSpecifier VectorizeAliasOption =
+      EnableVec ? options::OPT_O_Group : options::OPT_fvectorize;
+  if (Args.hasFlag(options::OPT_fvectorize, VectorizeAliasOption,
+                   options::OPT_fno_vectorize, EnableVec))
+    CmdArgs.push_back("-vectorize-loops");
+
+  // -fslp-vectorize is enabled based on the optimization level selected.
+  bool EnableSLPVec = shouldEnableVectorizerAtOLevel(Args, true);
+  OptSpecifier SLPVectAliasOption =
+      EnableSLPVec ? options::OPT_O_Group : options::OPT_fslp_vectorize;
+  if (Args.hasFlag(options::OPT_fslp_vectorize, SLPVectAliasOption,
+                   options::OPT_fno_slp_vectorize, EnableSLPVec))
+    CmdArgs.push_back("-vectorize-slp");
+
+  // -fno-slp-vectorize-aggressive is default.
+  if (Args.hasFlag(options::OPT_fslp_vectorize_aggressive,
+                   options::OPT_fno_slp_vectorize_aggressive, false))
+    CmdArgs.push_back("-vectorize-slp-aggressive");
+
+  if (Arg *A = Args.getLastArg(options::OPT_fshow_overloads_EQ))
+    A->render(Args, CmdArgs);
+
+  if (Arg *A = Args.getLastArg(
+          options::OPT_fsanitize_undefined_strip_path_components_EQ))
+    A->render(Args, CmdArgs);
+
+  // -fdollars-in-identifiers default varies depending on platform and
+  // language; only pass if specified.
+  if (Arg *A = Args.getLastArg(options::OPT_fdollars_in_identifiers,
+                               options::OPT_fno_dollars_in_identifiers)) {
+    if (A->getOption().matches(options::OPT_fdollars_in_identifiers))
+      CmdArgs.push_back("-fdollars-in-identifiers");
+    else
+      CmdArgs.push_back("-fno-dollars-in-identifiers");
+  }
+
+  // -funit-at-a-time is default, and we don't support -fno-unit-at-a-time for
+  // practical purposes.
+  if (Arg *A = Args.getLastArg(options::OPT_funit_at_a_time,
+                               options::OPT_fno_unit_at_a_time)) {
+    if (A->getOption().matches(options::OPT_fno_unit_at_a_time))
+      D.Diag(diag::warn_drv_clang_unsupported) << A->getAsString(Args);
+  }
+
+  if (Args.hasFlag(options::OPT_fapple_pragma_pack,
+                   options::OPT_fno_apple_pragma_pack, false))
+    CmdArgs.push_back("-fapple-pragma-pack");
+
+  // le32-specific flags:
+  //  -fno-math-builtin: clang should not convert math builtins to intrinsics
+  //                     by default.
+  if (getToolChain().getArch() == llvm::Triple::le32) {
+    CmdArgs.push_back("-fno-math-builtin");
+  }
+
+  if (Args.hasFlag(options::OPT_fsave_optimization_record,
+                   options::OPT_fno_save_optimization_record, false)) {
+    CmdArgs.push_back("-opt-record-file");
+
+    const Arg *A = Args.getLastArg(options::OPT_foptimization_record_file_EQ);
+    if (A) {
+      CmdArgs.push_back(A->getValue());
+    } else {
+      SmallString<128> F;
+      if (Output.isFilename() && (Args.hasArg(options::OPT_c) ||
+                                  Args.hasArg(options::OPT_S))) {
+        F = Output.getFilename();
+      } else {
+        // Use the input filename.
+        F = llvm::sys::path::stem(Input.getBaseInput());
+
+        // If we're compiling for an offload architecture (i.e. a CUDA device),
+        // we need to make the file name for the device compilation different
+        // from the host compilation.
+        if (!JA.isDeviceOffloading(Action::OFK_None) &&
+            !JA.isDeviceOffloading(Action::OFK_Host)) {
+          llvm::sys::path::replace_extension(F, "");
+          F += Action::GetOffloadingFileNamePrefix(JA.getOffloadingDeviceKind(),
+                                                   Triple.normalize());
+          F += "-";
+          F += JA.getOffloadingArch();
+        }
+      }
+
+      llvm::sys::path::replace_extension(F, "opt.yaml");
+      CmdArgs.push_back(Args.MakeArgString(F));
+    }
+  }
+
+// Default to -fno-builtin-str{cat,cpy} on Darwin for ARM.
+//
+// FIXME: Now that PR4941 has been fixed this can be enabled.
+#if 0
+  if (getToolChain().getTriple().isOSDarwin() &&
+      (getToolChain().getArch() == llvm::Triple::arm ||
+       getToolChain().getArch() == llvm::Triple::thumb)) {
+    if (!Args.hasArg(options::OPT_fbuiltin_strcat))
+      CmdArgs.push_back("-fno-builtin-strcat");
+    if (!Args.hasArg(options::OPT_fbuiltin_strcpy))
+      CmdArgs.push_back("-fno-builtin-strcpy");
+  }
+#endif
+
+  // Enable rewrite includes if the user's asked for it or if we're generating
+  // diagnostics.
+  // TODO: Once -module-dependency-dir works with -frewrite-includes it'd be
+  // nice to enable this when doing a crashdump for modules as well.
+  if (Args.hasFlag(options::OPT_frewrite_includes,
+                   options::OPT_fno_rewrite_includes, false) ||
+      (C.isForDiagnostics() && !HaveAnyModules))
+    CmdArgs.push_back("-frewrite-includes");
+
+  // Only allow -traditional or -traditional-cpp outside in preprocessing modes.
+  if (Arg *A = Args.getLastArg(options::OPT_traditional,
+                               options::OPT_traditional_cpp)) {
+    if (isa<PreprocessJobAction>(JA))
+      CmdArgs.push_back("-traditional-cpp");
+    else
+      D.Diag(diag::err_drv_clang_unsupported) << A->getAsString(Args);
+  }
+
+  Args.AddLastArg(CmdArgs, options::OPT_dM);
+  Args.AddLastArg(CmdArgs, options::OPT_dD);
+
+  // Handle serialized diagnostics.
+  if (Arg *A = Args.getLastArg(options::OPT__serialize_diags)) {
+    CmdArgs.push_back("-serialize-diagnostic-file");
+    CmdArgs.push_back(Args.MakeArgString(A->getValue()));
+  }
+
+  if (Args.hasArg(options::OPT_fretain_comments_from_system_headers))
+    CmdArgs.push_back("-fretain-comments-from-system-headers");
+
+  // Forward -fcomment-block-commands to -cc1.
+  Args.AddAllArgs(CmdArgs, options::OPT_fcomment_block_commands);
+  // Forward -fparse-all-comments to -cc1.
+  Args.AddAllArgs(CmdArgs, options::OPT_fparse_all_comments);
+
+  // Turn -fplugin=name.so into -load name.so
+  for (const Arg *A : Args.filtered(options::OPT_fplugin_EQ)) {
+    CmdArgs.push_back("-load");
+    CmdArgs.push_back(A->getValue());
+    A->claim();
+  }
+
+  // Setup statistics file output.
+  if (const Arg *A = Args.getLastArg(options::OPT_save_stats_EQ)) {
+    StringRef SaveStats = A->getValue();
+
+    SmallString<128> StatsFile;
+    bool DoSaveStats = false;
+    if (SaveStats == "obj") {
+      if (Output.isFilename()) {
+        StatsFile.assign(Output.getFilename());
+        llvm::sys::path::remove_filename(StatsFile);
+      }
+      DoSaveStats = true;
+    } else if (SaveStats == "cwd") {
+      DoSaveStats = true;
+    } else {
+      D.Diag(diag::err_drv_invalid_value) << A->getAsString(Args) << SaveStats;
+    }
+
+    if (DoSaveStats) {
+      StringRef BaseName = llvm::sys::path::filename(Input.getBaseInput());
+      llvm::sys::path::append(StatsFile, BaseName);
+      llvm::sys::path::replace_extension(StatsFile, "stats");
+      CmdArgs.push_back(Args.MakeArgString(Twine("-stats-file=") +
+                                           StatsFile));
+    }
+  }
+
+  // Forward -Xclang arguments to -cc1, and -mllvm arguments to the LLVM option
+  // parser.
+  // -finclude-default-header flag is for preprocessor,
+  // do not pass it to other cc1 commands when save-temps is enabled
+  if (C.getDriver().isSaveTempsEnabled() &&
+      !isa<PreprocessJobAction>(JA)) {
+    for (auto Arg : Args.filtered(options::OPT_Xclang)) {
+      Arg->claim();
+      if (StringRef(Arg->getValue()) != "-finclude-default-header")
+        CmdArgs.push_back(Arg->getValue());
+    }
+  }
+  else {
+    Args.AddAllArgValues(CmdArgs, options::OPT_Xclang);
+  }
+  for (const Arg *A : Args.filtered(options::OPT_mllvm)) {
+    A->claim();
+
+    // We translate this by hand to the -cc1 argument, since nightly test uses
+    // it and developers have been trained to spell it with -mllvm. Both
+    // spellings are now deprecated and should be removed.
+    if (StringRef(A->getValue(0)) == "-disable-llvm-optzns") {
+      CmdArgs.push_back("-disable-llvm-optzns");
+    } else {
+      A->render(Args, CmdArgs);
+    }
+  }
+
+  // With -save-temps, we want to save the unoptimized bitcode output from the
+  // CompileJobAction, use -disable-llvm-passes to get pristine IR generated
+  // by the frontend.
+  // When -fembed-bitcode is enabled, optimized bitcode is emitted because it
+  // has slightly different breakdown between stages.
+  // FIXME: -fembed-bitcode -save-temps will save optimized bitcode instead of
+  // pristine IR generated by the frontend. Ideally, a new compile action should
+  // be added so both IR can be captured.
+  if (C.getDriver().isSaveTempsEnabled() &&
+      !(C.getDriver().embedBitcodeInObject() && !C.getDriver().isUsingLTO()) &&
+      isa<CompileJobAction>(JA))
+    CmdArgs.push_back("-disable-llvm-passes");
+
+  if (Output.getType() == types::TY_Dependencies) {
+    // Handled with other dependency code.
+  } else if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Invalid output.");
+  }
+
+  addDashXForInput(Args, Input, CmdArgs);
+
+  if (Input.isFilename())
+    CmdArgs.push_back(Input.getFilename());
+  else
+    Input.getInputArg().renderAsInput(Args, CmdArgs);
+
+  Args.AddAllArgs(CmdArgs, options::OPT_undef);
+
+  const char *Exec = getToolChain().getDriver().getClangProgramPath();
+
+  // Optionally embed the -cc1 level arguments into the debug info, for build
+  // analysis.
+  // Also record command line arguments into the debug info if
+  // -grecord-gcc-switches options is set on.
+  // By default, -gno-record-gcc-switches is set on and no recording.
+  if (getToolChain().UseDwarfDebugFlags() ||
+      Args.hasFlag(options::OPT_grecord_gcc_switches,
+                   options::OPT_gno_record_gcc_switches, false)) {
+    ArgStringList OriginalArgs;
+    for (const auto &Arg : Args)
+      Arg->render(Args, OriginalArgs);
+
+    SmallString<256> Flags;
+    Flags += Exec;
+    for (const char *OriginalArg : OriginalArgs) {
+      SmallString<128> EscapedArg;
+      EscapeSpacesAndBackslashes(OriginalArg, EscapedArg);
+      Flags += " ";
+      Flags += EscapedArg;
+    }
+    CmdArgs.push_back("-dwarf-debug-flags");
+    CmdArgs.push_back(Args.MakeArgString(Flags));
+  }
+
+  // Add the split debug info name to the command lines here so we
+  // can propagate it to the backend.
+  bool SplitDwarf = SplitDwarfArg && getToolChain().getTriple().isOSLinux() &&
+                    (isa<AssembleJobAction>(JA) || isa<CompileJobAction>(JA) ||
+                     isa<BackendJobAction>(JA));
+  const char *SplitDwarfOut;
+  if (SplitDwarf) {
+    CmdArgs.push_back("-split-dwarf-file");
+    SplitDwarfOut = SplitDebugName(Args, Input);
+    CmdArgs.push_back(SplitDwarfOut);
+  }
+
+  // Host-side cuda compilation receives device-side outputs as Inputs[1...].
+  // Include them with -fcuda-include-gpubinary.
+  if (IsCuda && Inputs.size() > 1)
+    for (auto I = std::next(Inputs.begin()), E = Inputs.end(); I != E; ++I) {
+      CmdArgs.push_back("-fcuda-include-gpubinary");
+      CmdArgs.push_back(I->getFilename());
+    }
+
+  // OpenMP offloading device jobs take the argument -fopenmp-host-ir-file-path
+  // to specify the result of the compile phase on the host, so the meaningful
+  // device declarations can be identified. Also, -fopenmp-is-device is passed
+  // along to tell the frontend that it is generating code for a device, so that
+  // only the relevant declarations are emitted.
+  if (IsOpenMPDevice && Inputs.size() == 2) {
+    CmdArgs.push_back("-fopenmp-is-device");
+    CmdArgs.push_back("-fopenmp-host-ir-file-path");
+    CmdArgs.push_back(Args.MakeArgString(Inputs.back().getFilename()));
+  }
+
+  // For all the host OpenMP offloading compile jobs we need to pass the targets
+  // information using -fopenmp-targets= option.
+  if (isa<CompileJobAction>(JA) && JA.isHostOffloading(Action::OFK_OpenMP)) {
+    SmallString<128> TargetInfo("-fopenmp-targets=");
+
+    Arg *Tgts = Args.getLastArg(options::OPT_fopenmp_targets_EQ);
+    assert(Tgts && Tgts->getNumValues() &&
+           "OpenMP offloading has to have targets specified.");
+    for (unsigned i = 0; i < Tgts->getNumValues(); ++i) {
+      if (i)
+        TargetInfo += ',';
+      // We need to get the string from the triple because it may be not exactly
+      // the same as the one we get directly from the arguments.
+      llvm::Triple T(Tgts->getValue(i));
+      TargetInfo += T.getTriple();
+    }
+    CmdArgs.push_back(Args.MakeArgString(TargetInfo.str()));
+  }
+
+  bool WholeProgramVTables =
+      Args.hasFlag(options::OPT_fwhole_program_vtables,
+                   options::OPT_fno_whole_program_vtables, false);
+  if (WholeProgramVTables) {
+    if (!D.isUsingLTO())
+      D.Diag(diag::err_drv_argument_only_allowed_with)
+          << "-fwhole-program-vtables"
+          << "-flto";
+    CmdArgs.push_back("-fwhole-program-vtables");
+  }
+
+  // Finally add the compile command to the compilation.
+  if (Args.hasArg(options::OPT__SLASH_fallback) &&
+      Output.getType() == types::TY_Object &&
+      (InputType == types::TY_C || InputType == types::TY_CXX)) {
+    auto CLCommand =
+        getCLFallback()->GetCommand(C, JA, Output, Inputs, Args, LinkingOutput);
+    C.addCommand(llvm::make_unique<FallbackCommand>(
+        JA, *this, Exec, CmdArgs, Inputs, std::move(CLCommand)));
+  } else if (Args.hasArg(options::OPT__SLASH_fallback) &&
+             isa<PrecompileJobAction>(JA)) {
+    // In /fallback builds, run the main compilation even if the pch generation
+    // fails, so that the main compilation's fallback to cl.exe runs.
+    C.addCommand(llvm::make_unique<ForceSuccessCommand>(JA, *this, Exec,
+                                                        CmdArgs, Inputs));
+  } else {
+    C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
+  }
+
+  // Handle the debug info splitting at object creation time if we're
+  // creating an object.
+  // TODO: Currently only works on linux with newer objcopy.
+  if (SplitDwarf && Output.getType() == types::TY_Object)
+    SplitDebugInfo(getToolChain(), C, *this, JA, Args, Output, SplitDwarfOut);
+
+  if (Arg *A = Args.getLastArg(options::OPT_pg))
+    if (Args.hasArg(options::OPT_fomit_frame_pointer))
+      D.Diag(diag::err_drv_argument_not_allowed_with) << "-fomit-frame-pointer"
+                                                      << A->getAsString(Args);
+
+  // Claim some arguments which clang supports automatically.
+
+  // -fpch-preprocess is used with gcc to add a special marker in the output to
+  // include the PCH file. Clang's PTH solution is completely transparent, so we
+  // do not need to deal with it at all.
+  Args.ClaimAllArgs(options::OPT_fpch_preprocess);
+
+  // Claim some arguments which clang doesn't support, but we don't
+  // care to warn the user about.
+  Args.ClaimAllArgs(options::OPT_clang_ignored_f_Group);
+  Args.ClaimAllArgs(options::OPT_clang_ignored_m_Group);
+
+  // Disable warnings for clang -E -emit-llvm foo.c
+  Args.ClaimAllArgs(options::OPT_emit_llvm);
+}
+
+Clang::Clang(const ToolChain &TC)
+    // CAUTION! The first constructor argument ("clang") is not arbitrary,
+    // as it is for other tools. Some operations on a Tool actually test
+    // whether that tool is Clang based on the Tool's Name as a string.
+    : Tool("clang", "clang frontend", TC, RF_Full) {}
+
+Clang::~Clang() {}
+
+/// Add options related to the Objective-C runtime/ABI.
+///
+/// Returns true if the runtime is non-fragile.
+ObjCRuntime Clang::AddObjCRuntimeArgs(const ArgList &args,
+                                      ArgStringList &cmdArgs,
+                                      RewriteKind rewriteKind) const {
+  // Look for the controlling runtime option.
+  Arg *runtimeArg =
+      args.getLastArg(options::OPT_fnext_runtime, options::OPT_fgnu_runtime,
+                      options::OPT_fobjc_runtime_EQ);
+
+  // Just forward -fobjc-runtime= to the frontend.  This supercedes
+  // options about fragility.
+  if (runtimeArg &&
+      runtimeArg->getOption().matches(options::OPT_fobjc_runtime_EQ)) {
+    ObjCRuntime runtime;
+    StringRef value = runtimeArg->getValue();
+    if (runtime.tryParse(value)) {
+      getToolChain().getDriver().Diag(diag::err_drv_unknown_objc_runtime)
+          << value;
+    }
+
+    runtimeArg->render(args, cmdArgs);
+    return runtime;
+  }
+
+  // Otherwise, we'll need the ABI "version".  Version numbers are
+  // slightly confusing for historical reasons:
+  //   1 - Traditional "fragile" ABI
+  //   2 - Non-fragile ABI, version 1
+  //   3 - Non-fragile ABI, version 2
+  unsigned objcABIVersion = 1;
+  // If -fobjc-abi-version= is present, use that to set the version.
+  if (Arg *abiArg = args.getLastArg(options::OPT_fobjc_abi_version_EQ)) {
+    StringRef value = abiArg->getValue();
+    if (value == "1")
+      objcABIVersion = 1;
+    else if (value == "2")
+      objcABIVersion = 2;
+    else if (value == "3")
+      objcABIVersion = 3;
+    else
+      getToolChain().getDriver().Diag(diag::err_drv_clang_unsupported) << value;
+  } else {
+    // Otherwise, determine if we are using the non-fragile ABI.
+    bool nonFragileABIIsDefault =
+        (rewriteKind == RK_NonFragile ||
+         (rewriteKind == RK_None &&
+          getToolChain().IsObjCNonFragileABIDefault()));
+    if (args.hasFlag(options::OPT_fobjc_nonfragile_abi,
+                     options::OPT_fno_objc_nonfragile_abi,
+                     nonFragileABIIsDefault)) {
+// Determine the non-fragile ABI version to use.
+#ifdef DISABLE_DEFAULT_NONFRAGILEABI_TWO
+      unsigned nonFragileABIVersion = 1;
+#else
+      unsigned nonFragileABIVersion = 2;
+#endif
+
+      if (Arg *abiArg =
+              args.getLastArg(options::OPT_fobjc_nonfragile_abi_version_EQ)) {
+        StringRef value = abiArg->getValue();
+        if (value == "1")
+          nonFragileABIVersion = 1;
+        else if (value == "2")
+          nonFragileABIVersion = 2;
+        else
+          getToolChain().getDriver().Diag(diag::err_drv_clang_unsupported)
+              << value;
+      }
+
+      objcABIVersion = 1 + nonFragileABIVersion;
+    } else {
+      objcABIVersion = 1;
+    }
+  }
+
+  // We don't actually care about the ABI version other than whether
+  // it's non-fragile.
+  bool isNonFragile = objcABIVersion != 1;
+
+  // If we have no runtime argument, ask the toolchain for its default runtime.
+  // However, the rewriter only really supports the Mac runtime, so assume that.
+  ObjCRuntime runtime;
+  if (!runtimeArg) {
+    switch (rewriteKind) {
+    case RK_None:
+      runtime = getToolChain().getDefaultObjCRuntime(isNonFragile);
+      break;
+    case RK_Fragile:
+      runtime = ObjCRuntime(ObjCRuntime::FragileMacOSX, VersionTuple());
+      break;
+    case RK_NonFragile:
+      runtime = ObjCRuntime(ObjCRuntime::MacOSX, VersionTuple());
+      break;
+    }
+
+    // -fnext-runtime
+  } else if (runtimeArg->getOption().matches(options::OPT_fnext_runtime)) {
+    // On Darwin, make this use the default behavior for the toolchain.
+    if (getToolChain().getTriple().isOSDarwin()) {
+      runtime = getToolChain().getDefaultObjCRuntime(isNonFragile);
+
+      // Otherwise, build for a generic macosx port.
+    } else {
+      runtime = ObjCRuntime(ObjCRuntime::MacOSX, VersionTuple());
+    }
+
+    // -fgnu-runtime
+  } else {
+    assert(runtimeArg->getOption().matches(options::OPT_fgnu_runtime));
+    // Legacy behaviour is to target the gnustep runtime if we are in
+    // non-fragile mode or the GCC runtime in fragile mode.
+    if (isNonFragile)
+      runtime = ObjCRuntime(ObjCRuntime::GNUstep, VersionTuple(1, 6));
+    else
+      runtime = ObjCRuntime(ObjCRuntime::GCC, VersionTuple());
+  }
+
+  cmdArgs.push_back(
+      args.MakeArgString("-fobjc-runtime=" + runtime.getAsString()));
+  return runtime;
+}
+
+static bool maybeConsumeDash(const std::string &EH, size_t &I) {
+  bool HaveDash = (I + 1 < EH.size() && EH[I + 1] == '-');
+  I += HaveDash;
+  return !HaveDash;
+}
+
+namespace {
+struct EHFlags {
+  bool Synch = false;
+  bool Asynch = false;
+  bool NoUnwindC = false;
+};
+} // end anonymous namespace
+
+/// /EH controls whether to run destructor cleanups when exceptions are
+/// thrown.  There are three modifiers:
+/// - s: Cleanup after "synchronous" exceptions, aka C++ exceptions.
+/// - a: Cleanup after "asynchronous" exceptions, aka structured exceptions.
+///      The 'a' modifier is unimplemented and fundamentally hard in LLVM IR.
+/// - c: Assume that extern "C" functions are implicitly nounwind.
+/// The default is /EHs-c-, meaning cleanups are disabled.
+static EHFlags parseClangCLEHFlags(const Driver &D, const ArgList &Args) {
+  EHFlags EH;
+
+  std::vector<std::string> EHArgs =
+      Args.getAllArgValues(options::OPT__SLASH_EH);
+  for (auto EHVal : EHArgs) {
+    for (size_t I = 0, E = EHVal.size(); I != E; ++I) {
+      switch (EHVal[I]) {
+      case 'a':
+        EH.Asynch = maybeConsumeDash(EHVal, I);
+        if (EH.Asynch)
+          EH.Synch = false;
+        continue;
+      case 'c':
+        EH.NoUnwindC = maybeConsumeDash(EHVal, I);
+        continue;
+      case 's':
+        EH.Synch = maybeConsumeDash(EHVal, I);
+        if (EH.Synch)
+          EH.Asynch = false;
+        continue;
+      default:
+        break;
+      }
+      D.Diag(clang::diag::err_drv_invalid_value) << "/EH" << EHVal;
+      break;
+    }
+  }
+  // The /GX, /GX- flags are only processed if there are not /EH flags.
+  // The default is that /GX is not specified.
+  if (EHArgs.empty() &&
+      Args.hasFlag(options::OPT__SLASH_GX, options::OPT__SLASH_GX_,
+                   /*default=*/false)) {
+    EH.Synch = true;
+    EH.NoUnwindC = true;
+  }
+
+  return EH;
+}
+
+void Clang::AddClangCLArgs(const ArgList &Args, types::ID InputType,
+                           ArgStringList &CmdArgs,
+                           codegenoptions::DebugInfoKind *DebugInfoKind,
+                           bool *EmitCodeView) const {
+  unsigned RTOptionID = options::OPT__SLASH_MT;
+
+  if (Args.hasArg(options::OPT__SLASH_LDd))
+    // The /LDd option implies /MTd. The dependent lib part can be overridden,
+    // but defining _DEBUG is sticky.
+    RTOptionID = options::OPT__SLASH_MTd;
+
+  if (Arg *A = Args.getLastArg(options::OPT__SLASH_M_Group))
+    RTOptionID = A->getOption().getID();
+
+  StringRef FlagForCRT;
+  switch (RTOptionID) {
+  case options::OPT__SLASH_MD:
+    if (Args.hasArg(options::OPT__SLASH_LDd))
+      CmdArgs.push_back("-D_DEBUG");
+    CmdArgs.push_back("-D_MT");
+    CmdArgs.push_back("-D_DLL");
+    FlagForCRT = "--dependent-lib=msvcrt";
+    break;
+  case options::OPT__SLASH_MDd:
+    CmdArgs.push_back("-D_DEBUG");
+    CmdArgs.push_back("-D_MT");
+    CmdArgs.push_back("-D_DLL");
+    FlagForCRT = "--dependent-lib=msvcrtd";
+    break;
+  case options::OPT__SLASH_MT:
+    if (Args.hasArg(options::OPT__SLASH_LDd))
+      CmdArgs.push_back("-D_DEBUG");
+    CmdArgs.push_back("-D_MT");
+    CmdArgs.push_back("-flto-visibility-public-std");
+    FlagForCRT = "--dependent-lib=libcmt";
+    break;
+  case options::OPT__SLASH_MTd:
+    CmdArgs.push_back("-D_DEBUG");
+    CmdArgs.push_back("-D_MT");
+    CmdArgs.push_back("-flto-visibility-public-std");
+    FlagForCRT = "--dependent-lib=libcmtd";
+    break;
+  default:
+    llvm_unreachable("Unexpected option ID.");
+  }
+
+  if (Args.hasArg(options::OPT__SLASH_Zl)) {
+    CmdArgs.push_back("-D_VC_NODEFAULTLIB");
+  } else {
+    CmdArgs.push_back(FlagForCRT.data());
+
+    // This provides POSIX compatibility (maps 'open' to '_open'), which most
+    // users want.  The /Za flag to cl.exe turns this off, but it's not
+    // implemented in clang.
+    CmdArgs.push_back("--dependent-lib=oldnames");
+  }
+
+  // Both /showIncludes and /E (and /EP) write to stdout. Allowing both
+  // would produce interleaved output, so ignore /showIncludes in such cases.
+  if (!Args.hasArg(options::OPT_E) && !Args.hasArg(options::OPT__SLASH_EP))
+    if (Arg *A = Args.getLastArg(options::OPT_show_includes))
+      A->render(Args, CmdArgs);
+
+  // This controls whether or not we emit RTTI data for polymorphic types.
+  if (Args.hasFlag(options::OPT__SLASH_GR_, options::OPT__SLASH_GR,
+                   /*default=*/false))
+    CmdArgs.push_back("-fno-rtti-data");
+
+  // This controls whether or not we emit stack-protector instrumentation.
+  // In MSVC, Buffer Security Check (/GS) is on by default.
+  if (Args.hasFlag(options::OPT__SLASH_GS, options::OPT__SLASH_GS_,
+                   /*default=*/true)) {
+    CmdArgs.push_back("-stack-protector");
+    CmdArgs.push_back(Args.MakeArgString(Twine(LangOptions::SSPStrong)));
+  }
+
+  // Emit CodeView if -Z7, -Zd, or -gline-tables-only are present.
+  if (Arg *DebugInfoArg =
+          Args.getLastArg(options::OPT__SLASH_Z7, options::OPT__SLASH_Zd,
+                          options::OPT_gline_tables_only)) {
+    *EmitCodeView = true;
+    if (DebugInfoArg->getOption().matches(options::OPT__SLASH_Z7))
+      *DebugInfoKind = codegenoptions::LimitedDebugInfo;
+    else
+      *DebugInfoKind = codegenoptions::DebugLineTablesOnly;
+    CmdArgs.push_back("-gcodeview");
+  } else {
+    *EmitCodeView = false;
+  }
+
+  const Driver &D = getToolChain().getDriver();
+  EHFlags EH = parseClangCLEHFlags(D, Args);
+  if (EH.Synch || EH.Asynch) {
+    if (types::isCXX(InputType))
+      CmdArgs.push_back("-fcxx-exceptions");
+    CmdArgs.push_back("-fexceptions");
+  }
+  if (types::isCXX(InputType) && EH.Synch && EH.NoUnwindC)
+    CmdArgs.push_back("-fexternc-nounwind");
+
+  // /EP should expand to -E -P.
+  if (Args.hasArg(options::OPT__SLASH_EP)) {
+    CmdArgs.push_back("-E");
+    CmdArgs.push_back("-P");
+  }
+
+  unsigned VolatileOptionID;
+  if (getToolChain().getArch() == llvm::Triple::x86_64 ||
+      getToolChain().getArch() == llvm::Triple::x86)
+    VolatileOptionID = options::OPT__SLASH_volatile_ms;
+  else
+    VolatileOptionID = options::OPT__SLASH_volatile_iso;
+
+  if (Arg *A = Args.getLastArg(options::OPT__SLASH_volatile_Group))
+    VolatileOptionID = A->getOption().getID();
+
+  if (VolatileOptionID == options::OPT__SLASH_volatile_ms)
+    CmdArgs.push_back("-fms-volatile");
+
+  Arg *MostGeneralArg = Args.getLastArg(options::OPT__SLASH_vmg);
+  Arg *BestCaseArg = Args.getLastArg(options::OPT__SLASH_vmb);
+  if (MostGeneralArg && BestCaseArg)
+    D.Diag(clang::diag::err_drv_argument_not_allowed_with)
+        << MostGeneralArg->getAsString(Args) << BestCaseArg->getAsString(Args);
+
+  if (MostGeneralArg) {
+    Arg *SingleArg = Args.getLastArg(options::OPT__SLASH_vms);
+    Arg *MultipleArg = Args.getLastArg(options::OPT__SLASH_vmm);
+    Arg *VirtualArg = Args.getLastArg(options::OPT__SLASH_vmv);
+
+    Arg *FirstConflict = SingleArg ? SingleArg : MultipleArg;
+    Arg *SecondConflict = VirtualArg ? VirtualArg : MultipleArg;
+    if (FirstConflict && SecondConflict && FirstConflict != SecondConflict)
+      D.Diag(clang::diag::err_drv_argument_not_allowed_with)
+          << FirstConflict->getAsString(Args)
+          << SecondConflict->getAsString(Args);
+
+    if (SingleArg)
+      CmdArgs.push_back("-fms-memptr-rep=single");
+    else if (MultipleArg)
+      CmdArgs.push_back("-fms-memptr-rep=multiple");
+    else
+      CmdArgs.push_back("-fms-memptr-rep=virtual");
+  }
+
+  if (Args.getLastArg(options::OPT__SLASH_Gd))
+     CmdArgs.push_back("-fdefault-calling-conv=cdecl");
+  else if (Args.getLastArg(options::OPT__SLASH_Gr))
+     CmdArgs.push_back("-fdefault-calling-conv=fastcall");
+  else if (Args.getLastArg(options::OPT__SLASH_Gz))
+     CmdArgs.push_back("-fdefault-calling-conv=stdcall");
+  else if (Args.getLastArg(options::OPT__SLASH_Gv))
+     CmdArgs.push_back("-fdefault-calling-conv=vectorcall");
+
+  if (Arg *A = Args.getLastArg(options::OPT_vtordisp_mode_EQ))
+    A->render(Args, CmdArgs);
+
+  if (!Args.hasArg(options::OPT_fdiagnostics_format_EQ)) {
+    CmdArgs.push_back("-fdiagnostics-format");
+    if (Args.hasArg(options::OPT__SLASH_fallback))
+      CmdArgs.push_back("msvc-fallback");
+    else
+      CmdArgs.push_back("msvc");
+  }
+}
+
+visualstudio::Compiler *Clang::getCLFallback() const {
+  if (!CLFallback)
+    CLFallback.reset(new visualstudio::Compiler(getToolChain()));
+  return CLFallback.get();
+}
+
+
+const char *Clang::getBaseInputName(const ArgList &Args,
+                                    const InputInfo &Input) {
+  return Args.MakeArgString(llvm::sys::path::filename(Input.getBaseInput()));
+}
+
+const char *Clang::getBaseInputStem(const ArgList &Args,
+                                    const InputInfoList &Inputs) {
+  const char *Str = getBaseInputName(Args, Inputs[0]);
+
+  if (const char *End = strrchr(Str, '.'))
+    return Args.MakeArgString(std::string(Str, End));
+
+  return Str;
+}
+
+const char *Clang::getDependencyFileName(const ArgList &Args,
+                                         const InputInfoList &Inputs) {
+  // FIXME: Think about this more.
+  std::string Res;
+
+  if (Arg *OutputOpt = Args.getLastArg(options::OPT_o)) {
+    std::string Str(OutputOpt->getValue());
+    Res = Str.substr(0, Str.rfind('.'));
+  } else {
+    Res = getBaseInputStem(Args, Inputs);
+  }
+  return Args.MakeArgString(Res + ".d");
+}
+
+// Begin ClangAs
+
+void ClangAs::AddMIPSTargetArgs(const ArgList &Args,
+                                ArgStringList &CmdArgs) const {
+  StringRef CPUName;
+  StringRef ABIName;
+  const llvm::Triple &Triple = getToolChain().getTriple();
+  mips::getMipsCPUAndABI(Args, Triple, CPUName, ABIName);
+
+  CmdArgs.push_back("-target-abi");
+  CmdArgs.push_back(ABIName.data());
+}
+
+void ClangAs::AddX86TargetArgs(const ArgList &Args,
+                               ArgStringList &CmdArgs) const {
+  if (Arg *A = Args.getLastArg(options::OPT_masm_EQ)) {
+    StringRef Value = A->getValue();
+    if (Value == "intel" || Value == "att") {
+      CmdArgs.push_back("-mllvm");
+      CmdArgs.push_back(Args.MakeArgString("-x86-asm-syntax=" + Value));
+    } else {
+      getToolChain().getDriver().Diag(diag::err_drv_unsupported_option_argument)
+          << A->getOption().getName() << Value;
+    }
+  }
+}
+
+void ClangAs::ConstructJob(Compilation &C, const JobAction &JA,
+                           const InputInfo &Output, const InputInfoList &Inputs,
+                           const ArgList &Args,
+                           const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  assert(Inputs.size() == 1 && "Unexpected number of inputs.");
+  const InputInfo &Input = Inputs[0];
+
+  const llvm::Triple &Triple = getToolChain().getEffectiveTriple();
+  const std::string &TripleStr = Triple.getTriple();
+
+  // Don't warn about "clang -w -c foo.s"
+  Args.ClaimAllArgs(options::OPT_w);
+  // and "clang -emit-llvm -c foo.s"
+  Args.ClaimAllArgs(options::OPT_emit_llvm);
+
+  claimNoWarnArgs(Args);
+
+  // Invoke ourselves in -cc1as mode.
+  //
+  // FIXME: Implement custom jobs for internal actions.
+  CmdArgs.push_back("-cc1as");
+
+  // Add the "effective" target triple.
+  CmdArgs.push_back("-triple");
+  CmdArgs.push_back(Args.MakeArgString(TripleStr));
+
+  // Set the output mode, we currently only expect to be used as a real
+  // assembler.
+  CmdArgs.push_back("-filetype");
+  CmdArgs.push_back("obj");
+
+  // Set the main file name, so that debug info works even with
+  // -save-temps or preprocessed assembly.
+  CmdArgs.push_back("-main-file-name");
+  CmdArgs.push_back(Clang::getBaseInputName(Args, Input));
+
+  // Add the target cpu
+  std::string CPU = getCPUName(Args, Triple, /*FromAs*/ true);
+  if (!CPU.empty()) {
+    CmdArgs.push_back("-target-cpu");
+    CmdArgs.push_back(Args.MakeArgString(CPU));
+  }
+
+  // Add the target features
+  getTargetFeatures(getToolChain(), Triple, Args, CmdArgs, true);
+
+  // Ignore explicit -force_cpusubtype_ALL option.
+  (void)Args.hasArg(options::OPT_force__cpusubtype__ALL);
+