Vendor import of clang trunk r351319 (just before the release_80 branchvendor/clang/clang-trunk-r351319

point):
https://llvm.org/svn/llvm-project/cfe/trunk@351319

1 files changed, 29 insertions, 5 deletions

diff --git a/lib/Driver/ToolChains/Arch/X86.cpp b/lib/Driver/ToolChains/Arch/X86.cpp
index 7a4f836d2e1a..45648945d5ef 100644
--- a/lib/Driver/ToolChains/Arch/X86.cpp
+++ b/lib/Driver/ToolChains/Arch/X86.cpp
@@ -23,12 +23,8 @@ 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";
-
+    if (StringRef(A->getValue()) != "native")
       return A->getValue();
-    }
 
     // FIXME: Reject attempts to use -march=native unless the target matches
     // the host.
@@ -144,6 +140,34 @@ void x86::getX86TargetFeatures(const Driver &D, const llvm::Triple &Triple,
       Features.push_back("+ssse3");
   }
 
+  // Translate the high level `-mretpoline` flag to the specific target feature
+  // flags. We also detect if the user asked for retpoline external thunks but
+  // failed to ask for retpolines themselves (through any of the different
+  // flags). This is a bit hacky but keeps existing usages working. We should
+  // consider deprecating this and instead warn if the user requests external
+  // retpoline thunks and *doesn't* request some form of retpolines.
+  if (Args.hasArgNoClaim(options::OPT_mretpoline, options::OPT_mno_retpoline,
+                         options::OPT_mspeculative_load_hardening,
+                         options::OPT_mno_speculative_load_hardening)) {
+    if (Args.hasFlag(options::OPT_mretpoline, options::OPT_mno_retpoline,
+                     false)) {
+      Features.push_back("+retpoline-indirect-calls");
+      Features.push_back("+retpoline-indirect-branches");
+    } else if (Args.hasFlag(options::OPT_mspeculative_load_hardening,
+                            options::OPT_mno_speculative_load_hardening,
+                            false)) {
+      // On x86, speculative load hardening relies on at least using retpolines
+      // for indirect calls.
+      Features.push_back("+retpoline-indirect-calls");
+    }
+  } else if (Args.hasFlag(options::OPT_mretpoline_external_thunk,
+                          options::OPT_mno_retpoline_external_thunk, false)) {
+    // FIXME: Add a warning about failing to specify `-mretpoline` and
+    // eventually switch to an error here.
+    Features.push_back("+retpoline-indirect-calls");
+    Features.push_back("+retpoline-indirect-branches");
+  }
+
   // 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);