Vendor import of stripped clang trunk r375505, the last commit beforevendor/clang/clang-trunk-r375505vendor/clang

the upstream Subversion repository was made read-only, and the LLVM
project migrated to GitHub:

https://llvm.org/svn/llvm-project/cfe/trunk@375505

38 files changed, 1439 insertions, 666 deletions

diff --git a/lib/Tooling/ASTDiff/ASTDiff.cpp b/lib/Tooling/ASTDiff/ASTDiff.cpp
index 69eff20bff7a..00db7702cd8b 100644
--- a/lib/Tooling/ASTDiff/ASTDiff.cpp
+++ b/lib/Tooling/ASTDiff/ASTDiff.cpp
@@ -35,8 +35,8 @@ public:
   Mapping &operator=(Mapping &&Other) = default;
 
   Mapping(size_t Size) {
-    SrcToDst = llvm::make_unique<NodeId[]>(Size);
-    DstToSrc = llvm::make_unique<NodeId[]>(Size);
+    SrcToDst = std::make_unique<NodeId[]>(Size);
+    DstToSrc = std::make_unique<NodeId[]>(Size);
   }
 
   void link(NodeId Src, NodeId Dst) {
@@ -565,13 +565,13 @@ public:
   ZhangShashaMatcher(const ASTDiff::Impl &DiffImpl, const SyntaxTree::Impl &T1,
                      const SyntaxTree::Impl &T2, NodeId Id1, NodeId Id2)
       : DiffImpl(DiffImpl), S1(T1, Id1), S2(T2, Id2) {
-    TreeDist = llvm::make_unique<std::unique_ptr<double[]>[]>(
+    TreeDist = std::make_unique<std::unique_ptr<double[]>[]>(
         size_t(S1.getSize()) + 1);
-    ForestDist = llvm::make_unique<std::unique_ptr<double[]>[]>(
+    ForestDist = std::make_unique<std::unique_ptr<double[]>[]>(
         size_t(S1.getSize()) + 1);
     for (int I = 0, E = S1.getSize() + 1; I < E; ++I) {
-      TreeDist[I] = llvm::make_unique<double[]>(size_t(S2.getSize()) + 1);
-      ForestDist[I] = llvm::make_unique<double[]>(size_t(S2.getSize()) + 1);
+      TreeDist[I] = std::make_unique<double[]>(size_t(S2.getSize()) + 1);
+      ForestDist[I] = std::make_unique<double[]>(size_t(S2.getSize()) + 1);
     }
   }
 
@@ -960,7 +960,7 @@ void ASTDiff::Impl::computeChangeKinds(Mapping &M) {
 
 ASTDiff::ASTDiff(SyntaxTree &T1, SyntaxTree &T2,
                  const ComparisonOptions &Options)
-    : DiffImpl(llvm::make_unique<Impl>(*T1.TreeImpl, *T2.TreeImpl, Options)) {}
+    : DiffImpl(std::make_unique<Impl>(*T1.TreeImpl, *T2.TreeImpl, Options)) {}
 
 ASTDiff::~ASTDiff() = default;
 
@@ -969,7 +969,7 @@ NodeId ASTDiff::getMapped(const SyntaxTree &SourceTree, NodeId Id) const {
 }
 
 SyntaxTree::SyntaxTree(ASTContext &AST)
-    : TreeImpl(llvm::make_unique<SyntaxTree::Impl>(
+    : TreeImpl(std::make_unique<SyntaxTree::Impl>(
           this, AST.getTranslationUnitDecl(), AST)) {}
 
 SyntaxTree::~SyntaxTree() = default;
diff --git a/lib/Tooling/AllTUsExecution.cpp b/lib/Tooling/AllTUsExecution.cpp
index ca9db7a561be..d85075f59607 100644
--- a/lib/Tooling/AllTUsExecution.cpp
+++ b/lib/Tooling/AllTUsExecution.cpp
@@ -8,6 +8,7 @@
 
 #include "clang/Tooling/AllTUsExecution.h"
 #include "clang/Tooling/ToolExecutorPluginRegistry.h"
+#include "llvm/Support/Threading.h"
 #include "llvm/Support/ThreadPool.h"
 #include "llvm/Support/VirtualFileSystem.h"
 
@@ -147,7 +148,7 @@ llvm::Error AllTUsToolExecutor::execute(
   return llvm::Error::success();
 }
 
-static llvm::cl::opt<unsigned> ExecutorConcurrency(
+llvm::cl::opt<unsigned> ExecutorConcurrency(
     "execute-concurrency",
     llvm::cl::desc("The number of threads used to process all files in "
                    "parallel. Set to 0 for hardware concurrency. "
@@ -162,7 +163,7 @@ public:
       return make_string_error(
           "[AllTUsToolExecutorPlugin] Please provide a directory/file path in "
           "the compilation database.");
-    return llvm::make_unique<AllTUsToolExecutor>(std::move(OptionsParser),
+    return std::make_unique<AllTUsToolExecutor>(std::move(OptionsParser),
                                                  ExecutorConcurrency);
   }
 };
diff --git a/lib/Tooling/ArgumentsAdjusters.cpp b/lib/Tooling/ArgumentsAdjusters.cpp
index 942b35df453e..f56d08c47b9a 100644
--- a/lib/Tooling/ArgumentsAdjusters.cpp
+++ b/lib/Tooling/ArgumentsAdjusters.cpp
@@ -57,6 +57,22 @@ ArgumentsAdjuster getClangStripOutputAdjuster() {
   };
 }
 
+ArgumentsAdjuster getClangStripSerializeDiagnosticAdjuster() {
+  return [](const CommandLineArguments &Args, StringRef /*unused*/) {
+    CommandLineArguments AdjustedArgs;
+    for (size_t i = 0, e = Args.size(); i < e; ++i) {
+      StringRef Arg = Args[i];
+      if (Arg == "--serialize-diagnostics") {
+        // Skip the diagnostic output argument.
+        ++i;
+        continue;
+      }
+      AdjustedArgs.push_back(Args[i]);
+    }
+    return AdjustedArgs;
+  };
+}
+
 ArgumentsAdjuster getClangStripDependencyFileAdjuster() {
   return [](const CommandLineArguments &Args, StringRef /*unused*/) {
     CommandLineArguments AdjustedArgs;
diff --git a/lib/Tooling/CommonOptionsParser.cpp b/lib/Tooling/CommonOptionsParser.cpp
index f7956f7998f5..5d881aab1e0d 100644
--- a/lib/Tooling/CommonOptionsParser.cpp
+++ b/lib/Tooling/CommonOptionsParser.cpp
@@ -142,7 +142,7 @@ llvm::Error CommonOptionsParser::init(
     }
   }
   auto AdjustingCompilations =
-      llvm::make_unique<ArgumentsAdjustingCompilations>(
+      std::make_unique<ArgumentsAdjustingCompilations>(
           std::move(Compilations));
   Adjuster =
       getInsertArgumentAdjuster(ArgsBefore, ArgumentInsertPosition::BEGIN);
diff --git a/lib/Tooling/CompilationDatabase.cpp b/lib/Tooling/CompilationDatabase.cpp
index 4c64750bef19..c453e8d7df19 100644
--- a/lib/Tooling/CompilationDatabase.cpp
+++ b/lib/Tooling/CompilationDatabase.cpp
@@ -356,7 +356,7 @@ FixedCompilationDatabase::loadFromCommandLine(int &Argc,
   std::vector<std::string> StrippedArgs;
   if (!stripPositionalArgs(CommandLine, StrippedArgs, ErrorMsg))
     return nullptr;
-  return llvm::make_unique<FixedCompilationDatabase>(Directory, StrippedArgs);
+  return std::make_unique<FixedCompilationDatabase>(Directory, StrippedArgs);
 }
 
 std::unique_ptr<FixedCompilationDatabase>
@@ -370,7 +370,7 @@ FixedCompilationDatabase::loadFromFile(StringRef Path, std::string &ErrorMsg) {
   }
   std::vector<std::string> Args{llvm::line_iterator(**File),
                                 llvm::line_iterator()};
-  return llvm::make_unique<FixedCompilationDatabase>(
+  return std::make_unique<FixedCompilationDatabase>(
       llvm::sys::path::parent_path(Path), std::move(Args));
 }
 
diff --git a/lib/Tooling/Core/Replacement.cpp b/lib/Tooling/Core/Replacement.cpp
index 546158714e3c..9ed03655bf2c 100644
--- a/lib/Tooling/Core/Replacement.cpp
+++ b/lib/Tooling/Core/Replacement.cpp
@@ -67,11 +67,11 @@ bool Replacement::isApplicable() const {
 
 bool Replacement::apply(Rewriter &Rewrite) const {
   SourceManager &SM = Rewrite.getSourceMgr();
-  const FileEntry *Entry = SM.getFileManager().getFile(FilePath);
+  auto Entry = SM.getFileManager().getFile(FilePath);
   if (!Entry)
     return false;
 
-  FileID ID = SM.getOrCreateFileID(Entry, SrcMgr::C_User);
+  FileID ID = SM.getOrCreateFileID(*Entry, SrcMgr::C_User);
   const SourceLocation Start =
     SM.getLocForStartOfFile(ID).
     getLocWithOffset(ReplacementRange.getOffset());
@@ -591,7 +591,8 @@ llvm::Expected<std::string> applyAllReplacements(StringRef Code,
   Rewriter Rewrite(SourceMgr, LangOptions());
   InMemoryFileSystem->addFile(
       "<stdin>", 0, llvm::MemoryBuffer::getMemBuffer(Code, "<stdin>"));
-  FileID ID = SourceMgr.createFileID(Files.getFile("<stdin>"), SourceLocation(),
+  FileID ID = SourceMgr.createFileID(*Files.getFile("<stdin>"),
+                                     SourceLocation(),
                                      clang::SrcMgr::C_User);
   for (auto I = Replaces.rbegin(), E = Replaces.rend(); I != E; ++I) {
     Replacement Replace("<stdin>", I->getOffset(), I->getLength(),
@@ -613,10 +614,10 @@ std::map<std::string, Replacements> groupReplacementsByFile(
   std::map<std::string, Replacements> Result;
   llvm::SmallPtrSet<const FileEntry *, 16> ProcessedFileEntries;
   for (const auto &Entry : FileToReplaces) {
-    const FileEntry *FE = FileMgr.getFile(Entry.first);
+    auto FE = FileMgr.getFile(Entry.first);
     if (!FE)
       llvm::errs() << "File path " << Entry.first << " is invalid.\n";
-    else if (ProcessedFileEntries.insert(FE).second)
+    else if (ProcessedFileEntries.insert(*FE).second)
       Result[Entry.first] = std::move(Entry.second);
   }
   return Result;
diff --git a/lib/Tooling/DependencyScanning/DependencyScanningFilesystem.cpp b/lib/Tooling/DependencyScanning/DependencyScanningFilesystem.cpp
new file mode 100644
index 000000000000..7436c7256327
--- /dev/null
+++ b/lib/Tooling/DependencyScanning/DependencyScanningFilesystem.cpp
@@ -0,0 +1,234 @@
+//===- DependencyScanningFilesystem.cpp - clang-scan-deps fs --------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/DependencyScanning/DependencyScanningFilesystem.h"
+#include "clang/Lex/DependencyDirectivesSourceMinimizer.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Threading.h"
+
+using namespace clang;
+using namespace tooling;
+using namespace dependencies;
+
+CachedFileSystemEntry CachedFileSystemEntry::createFileEntry(
+    StringRef Filename, llvm::vfs::FileSystem &FS, bool Minimize) {
+  // Load the file and its content from the file system.
+  llvm::ErrorOr<std::unique_ptr<llvm::vfs::File>> MaybeFile =
+      FS.openFileForRead(Filename);
+  if (!MaybeFile)
+    return MaybeFile.getError();
+  llvm::ErrorOr<llvm::vfs::Status> Stat = (*MaybeFile)->status();
+  if (!Stat)
+    return Stat.getError();
+
+  llvm::vfs::File &F = **MaybeFile;
+  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MaybeBuffer =
+      F.getBuffer(Stat->getName());
+  if (!MaybeBuffer)
+    return MaybeBuffer.getError();
+
+  llvm::SmallString<1024> MinimizedFileContents;
+  // Minimize the file down to directives that might affect the dependencies.
+  const auto &Buffer = *MaybeBuffer;
+  SmallVector<minimize_source_to_dependency_directives::Token, 64> Tokens;
+  if (!Minimize || minimizeSourceToDependencyDirectives(
+                       Buffer->getBuffer(), MinimizedFileContents, Tokens)) {
+    // Use the original file unless requested otherwise, or
+    // if the minimization failed.
+    // FIXME: Propage the diagnostic if desired by the client.
+    CachedFileSystemEntry Result;
+    Result.MaybeStat = std::move(*Stat);
+    Result.Contents.reserve(Buffer->getBufferSize() + 1);
+    Result.Contents.append(Buffer->getBufferStart(), Buffer->getBufferEnd());
+    // Implicitly null terminate the contents for Clang's lexer.
+    Result.Contents.push_back('\0');
+    Result.Contents.pop_back();
+    return Result;
+  }
+
+  CachedFileSystemEntry Result;
+  size_t Size = MinimizedFileContents.size();
+  Result.MaybeStat = llvm::vfs::Status(Stat->getName(), Stat->getUniqueID(),
+                                       Stat->getLastModificationTime(),
+                                       Stat->getUser(), Stat->getGroup(), Size,
+                                       Stat->getType(), Stat->getPermissions());
+  // The contents produced by the minimizer must be null terminated.
+  assert(MinimizedFileContents.data()[MinimizedFileContents.size()] == '\0' &&
+         "not null terminated contents");
+  // Even though there's an implicit null terminator in the minimized contents,
+  // we want to temporarily make it explicit. This will ensure that the
+  // std::move will preserve it even if it needs to do a copy if the
+  // SmallString still has the small capacity.
+  MinimizedFileContents.push_back('\0');
+  Result.Contents = std::move(MinimizedFileContents);
+  // Now make the null terminator implicit again, so that Clang's lexer can find
+  // it right where the buffer ends.
+  Result.Contents.pop_back();
+
+  // Compute the skipped PP ranges that speedup skipping over inactive
+  // preprocessor blocks.
+  llvm::SmallVector<minimize_source_to_dependency_directives::SkippedRange, 32>
+      SkippedRanges;
+  minimize_source_to_dependency_directives::computeSkippedRanges(Tokens,
+                                                                 SkippedRanges);
+  PreprocessorSkippedRangeMapping Mapping;
+  for (const auto &Range : SkippedRanges) {
+    if (Range.Length < 16) {
+      // Ignore small ranges as non-profitable.
+      // FIXME: This is a heuristic, its worth investigating the tradeoffs
+      // when it should be applied.
+      continue;
+    }
+    Mapping[Range.Offset] = Range.Length;
+  }
+  Result.PPSkippedRangeMapping = std::move(Mapping);
+
+  return Result;
+}
+
+CachedFileSystemEntry
+CachedFileSystemEntry::createDirectoryEntry(llvm::vfs::Status &&Stat) {
+  assert(Stat.isDirectory() && "not a directory!");
+  auto Result = CachedFileSystemEntry();
+  Result.MaybeStat = std::move(Stat);
+  return Result;
+}
+
+DependencyScanningFilesystemSharedCache::
+    DependencyScanningFilesystemSharedCache() {
+  // This heuristic was chosen using a empirical testing on a
+  // reasonably high core machine (iMacPro 18 cores / 36 threads). The cache
+  // sharding gives a performance edge by reducing the lock contention.
+  // FIXME: A better heuristic might also consider the OS to account for
+  // the different cost of lock contention on different OSes.
+  NumShards = std::max(2u, llvm::hardware_concurrency() / 4);
+  CacheShards = std::make_unique<CacheShard[]>(NumShards);
+}
+
+/// Returns a cache entry for the corresponding key.
+///
+/// A new cache entry is created if the key is not in the cache. This is a
+/// thread safe call.
+DependencyScanningFilesystemSharedCache::SharedFileSystemEntry &
+DependencyScanningFilesystemSharedCache::get(StringRef Key) {
+  CacheShard &Shard = CacheShards[llvm::hash_value(Key) % NumShards];
+  std::unique_lock<std::mutex> LockGuard(Shard.CacheLock);
+  auto It = Shard.Cache.try_emplace(Key);
+  return It.first->getValue();
+}
+
+llvm::ErrorOr<const CachedFileSystemEntry *>
+DependencyScanningWorkerFilesystem::getOrCreateFileSystemEntry(
+    const StringRef Filename) {
+  if (const CachedFileSystemEntry *Entry = getCachedEntry(Filename)) {
+    return Entry;
+  }
+
+  // FIXME: Handle PCM/PCH files.
+  // FIXME: Handle module map files.
+
+  bool KeepOriginalSource = IgnoredFiles.count(Filename);
+  DependencyScanningFilesystemSharedCache::SharedFileSystemEntry
+      &SharedCacheEntry = SharedCache.get(Filename);
+  const CachedFileSystemEntry *Result;
+  {
+    std::unique_lock<std::mutex> LockGuard(SharedCacheEntry.ValueLock);
+    CachedFileSystemEntry &CacheEntry = SharedCacheEntry.Value;
+
+    if (!CacheEntry.isValid()) {
+      llvm::vfs::FileSystem &FS = getUnderlyingFS();
+      auto MaybeStatus = FS.status(Filename);
+      if (!MaybeStatus)
+        CacheEntry = CachedFileSystemEntry(MaybeStatus.getError());
+      else if (MaybeStatus->isDirectory())
+        CacheEntry = CachedFileSystemEntry::createDirectoryEntry(
+            std::move(*MaybeStatus));
+      else
+        CacheEntry = CachedFileSystemEntry::createFileEntry(
+            Filename, FS, !KeepOriginalSource);
+    }
+
+    Result = &CacheEntry;
+  }
+
+  // Store the result in the local cache.
+  setCachedEntry(Filename, Result);
+  return Result;
+}
+
+llvm::ErrorOr<llvm::vfs::Status>
+DependencyScanningWorkerFilesystem::status(const Twine &Path) {
+  SmallString<256> OwnedFilename;
+  StringRef Filename = Path.toStringRef(OwnedFilename);
+  const llvm::ErrorOr<const CachedFileSystemEntry *> Result =
+      getOrCreateFileSystemEntry(Filename);
+  if (!Result)
+    return Result.getError();
+  return (*Result)->getStatus();
+}
+
+namespace {
+
+/// The VFS that is used by clang consumes the \c CachedFileSystemEntry using
+/// this subclass.
+class MinimizedVFSFile final : public llvm::vfs::File {
+public:
+  MinimizedVFSFile(std::unique_ptr<llvm::MemoryBuffer> Buffer,
+                   llvm::vfs::Status Stat)
+      : Buffer(std::move(Buffer)), Stat(std::move(Stat)) {}
+
+  llvm::ErrorOr<llvm::vfs::Status> status() override { return Stat; }
+
+  const llvm::MemoryBuffer *getBufferPtr() const { return Buffer.get(); }
+
+  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
+  getBuffer(const Twine &Name, int64_t FileSize, bool RequiresNullTerminator,
+            bool IsVolatile) override {
+    return std::move(Buffer);
+  }
+
+  std::error_code close() override { return {}; }
+
+private:
+  std::unique_ptr<llvm::MemoryBuffer> Buffer;
+  llvm::vfs::Status Stat;
+};
+
+llvm::ErrorOr<std::unique_ptr<llvm::vfs::File>>
+createFile(const CachedFileSystemEntry *Entry,
+           ExcludedPreprocessorDirectiveSkipMapping *PPSkipMappings) {
+  if (Entry->isDirectory())
+    return llvm::ErrorOr<std::unique_ptr<llvm::vfs::File>>(
+        std::make_error_code(std::errc::is_a_directory));
+  llvm::ErrorOr<StringRef> Contents = Entry->getContents();
+  if (!Contents)
+    return Contents.getError();
+  auto Result = std::make_unique<MinimizedVFSFile>(
+      llvm::MemoryBuffer::getMemBuffer(*Contents, Entry->getName(),
+                                       /*RequiresNullTerminator=*/false),
+      *Entry->getStatus());
+  if (!Entry->getPPSkippedRangeMapping().empty() && PPSkipMappings)
+    (*PPSkipMappings)[Result->getBufferPtr()] =
+        &Entry->getPPSkippedRangeMapping();
+  return llvm::ErrorOr<std::unique_ptr<llvm::vfs::File>>(
+      std::unique_ptr<llvm::vfs::File>(std::move(Result)));
+}
+
+} // end anonymous namespace
+
+llvm::ErrorOr<std::unique_ptr<llvm::vfs::File>>
+DependencyScanningWorkerFilesystem::openFileForRead(const Twine &Path) {
+  SmallString<256> OwnedFilename;
+  StringRef Filename = Path.toStringRef(OwnedFilename);
+
+  const llvm::ErrorOr<const CachedFileSystemEntry *> Result =
+      getOrCreateFileSystemEntry(Filename);
+  if (!Result)
+    return Result.getError();
+  return createFile(Result.get(), PPSkipMappings);
+}
diff --git a/lib/Tooling/DependencyScanning/DependencyScanningService.cpp b/lib/Tooling/DependencyScanning/DependencyScanningService.cpp
new file mode 100644
index 000000000000..e5cebe381000
--- /dev/null
+++ b/lib/Tooling/DependencyScanning/DependencyScanningService.cpp
@@ -0,0 +1,19 @@
+//===- DependencyScanningService.cpp - clang-scan-deps service ------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/DependencyScanning/DependencyScanningService.h"
+
+using namespace clang;
+using namespace tooling;
+using namespace dependencies;
+
+DependencyScanningService::DependencyScanningService(ScanningMode Mode,
+                                                     bool ReuseFileManager,
+                                                     bool SkipExcludedPPRanges)
+    : Mode(Mode), ReuseFileManager(ReuseFileManager),
+      SkipExcludedPPRanges(SkipExcludedPPRanges) {}
diff --git a/lib/Tooling/DependencyScanning/DependencyScanningTool.cpp b/lib/Tooling/DependencyScanning/DependencyScanningTool.cpp
new file mode 100644
index 000000000000..82b3ae806c65
--- /dev/null
+++ b/lib/Tooling/DependencyScanning/DependencyScanningTool.cpp
@@ -0,0 +1,71 @@
+//===- DependencyScanningTool.cpp - clang-scan-deps service ------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/DependencyScanning/DependencyScanningTool.h"
+#include "clang/Frontend/Utils.h"
+
+namespace clang{
+namespace tooling{
+namespace dependencies{
+
+DependencyScanningTool::DependencyScanningTool(DependencyScanningService &Service,
+const tooling::CompilationDatabase &Compilations) : Worker(Service), Compilations(Compilations) {}
+
+llvm::Expected<std::string> DependencyScanningTool::getDependencyFile(const std::string &Input,
+                                              StringRef CWD) {
+  /// Prints out all of the gathered dependencies into a string.
+  class DependencyPrinterConsumer : public DependencyConsumer {
+  public:
+    void handleFileDependency(const DependencyOutputOptions &Opts,
+                              StringRef File) override {
+      if (!this->Opts)
+        this->Opts = std::make_unique<DependencyOutputOptions>(Opts);
+      Dependencies.push_back(File);
+    }
+
+    void printDependencies(std::string &S) {
+      if (!Opts)
+        return;
+
+      class DependencyPrinter : public DependencyFileGenerator {
+      public:
+        DependencyPrinter(DependencyOutputOptions &Opts,
+                          ArrayRef<std::string> Dependencies)
+            : DependencyFileGenerator(Opts) {
+          for (const auto &Dep : Dependencies)
+            addDependency(Dep);
+        }
+
+        void printDependencies(std::string &S) {
+          llvm::raw_string_ostream OS(S);
+          outputDependencyFile(OS);
+        }
+      };
+
+      DependencyPrinter Generator(*Opts, Dependencies);
+      Generator.printDependencies(S);
+    }
+
+  private:
+    std::unique_ptr<DependencyOutputOptions> Opts;
+    std::vector<std::string> Dependencies;
+  };
+
+  DependencyPrinterConsumer Consumer;
+  auto Result =
+      Worker.computeDependencies(Input, CWD, Compilations, Consumer);
+  if (Result)
+    return std::move(Result);
+  std::string Output;
+  Consumer.printDependencies(Output);
+  return Output;
+}
+
+} // end namespace dependencies
+} // end namespace tooling
+} // end namespace clang
diff --git a/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp b/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
index 4868f2663796..f382c202f8c2 100644
--- a/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
+++ b/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
@@ -8,9 +8,12 @@
 
 #include "clang/Tooling/DependencyScanning/DependencyScanningWorker.h"
 #include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/FrontendActions.h"
 #include "clang/Frontend/TextDiagnosticPrinter.h"
 #include "clang/Frontend/Utils.h"
+#include "clang/Lex/PreprocessorOptions.h"
+#include "clang/Tooling/DependencyScanning/DependencyScanningService.h"
 #include "clang/Tooling/Tooling.h"
 
 using namespace clang;
@@ -19,21 +22,25 @@ using namespace dependencies;
 
 namespace {
 
-/// Prints out all of the gathered dependencies into a string.
-class DependencyPrinter : public DependencyFileGenerator {
+/// Forwards the gatherered dependencies to the consumer.
+class DependencyConsumerForwarder : public DependencyFileGenerator {
 public:
-  DependencyPrinter(std::unique_ptr<DependencyOutputOptions> Opts,
-                    std::string &S)
-      : DependencyFileGenerator(*Opts), Opts(std::move(Opts)), S(S) {}
+  DependencyConsumerForwarder(std::unique_ptr<DependencyOutputOptions> Opts,
+                              DependencyConsumer &C)
+      : DependencyFileGenerator(*Opts), Opts(std::move(Opts)), C(C) {}
 
   void finishedMainFile(DiagnosticsEngine &Diags) override {
-    llvm::raw_string_ostream OS(S);
-    outputDependencyFile(OS);
+    llvm::SmallString<256> CanonPath;
+    for (const auto &File : getDependencies()) {
+      CanonPath = File;
+      llvm::sys::path::remove_dots(CanonPath, /*remove_dot_dot=*/true);
+      C.handleFileDependency(*Opts, CanonPath);
+    }
   }
 
 private:
   std::unique_ptr<DependencyOutputOptions> Opts;
-  std::string &S;
+  DependencyConsumer &C;
 };
 
 /// A proxy file system that doesn't call `chdir` when changing the working
@@ -62,10 +69,12 @@ private:
 /// dependency scanning for the given compiler invocation.
 class DependencyScanningAction : public tooling::ToolAction {
 public:
-  DependencyScanningAction(StringRef WorkingDirectory,
-                           std::string &DependencyFileContents)
-      : WorkingDirectory(WorkingDirectory),
-        DependencyFileContents(DependencyFileContents) {}
+  DependencyScanningAction(
+      StringRef WorkingDirectory, DependencyConsumer &Consumer,
+      llvm::IntrusiveRefCntPtr<DependencyScanningWorkerFilesystem> DepFS,
+      ExcludedPreprocessorDirectiveSkipMapping *PPSkipMappings)
+      : WorkingDirectory(WorkingDirectory), Consumer(Consumer),
+        DepFS(std::move(DepFS)), PPSkipMappings(PPSkipMappings) {}
 
   bool runInvocation(std::shared_ptr<CompilerInvocation> Invocation,
                      FileManager *FileMgr,
@@ -74,8 +83,6 @@ public:
     // Create a compiler instance to handle the actual work.
     CompilerInstance Compiler(std::move(PCHContainerOps));
     Compiler.setInvocation(std::move(Invocation));
-    FileMgr->getFileSystemOpts().WorkingDir = WorkingDirectory;
-    Compiler.setFileManager(FileMgr);
 
     // Don't print 'X warnings and Y errors generated'.
     Compiler.getDiagnosticOpts().ShowCarets = false;
@@ -84,6 +91,32 @@ public:
     if (!Compiler.hasDiagnostics())
       return false;
 
+    // Use the dependency scanning optimized file system if we can.
+    if (DepFS) {
+      const CompilerInvocation &CI = Compiler.getInvocation();
+      // Add any filenames that were explicity passed in the build settings and
+      // that might be opened, as we want to ensure we don't run source
+      // minimization on them.
+      DepFS->IgnoredFiles.clear();
+      for (const auto &Entry : CI.getHeaderSearchOpts().UserEntries)
+        DepFS->IgnoredFiles.insert(Entry.Path);
+      for (const auto &Entry : CI.getHeaderSearchOpts().VFSOverlayFiles)
+        DepFS->IgnoredFiles.insert(Entry);
+
+      // Support for virtual file system overlays on top of the caching
+      // filesystem.
+      FileMgr->setVirtualFileSystem(createVFSFromCompilerInvocation(
+          CI, Compiler.getDiagnostics(), DepFS));
+
+      // Pass the skip mappings which should speed up excluded conditional block
+      // skipping in the preprocessor.
+      if (PPSkipMappings)
+        Compiler.getPreprocessorOpts()
+            .ExcludedConditionalDirectiveSkipMappings = PPSkipMappings;
+    }
+
+    FileMgr->getFileSystemOpts().WorkingDir = WorkingDirectory;
+    Compiler.setFileManager(FileMgr);
     Compiler.createSourceManager(*FileMgr);
 
     // Create the dependency collector that will collect the produced
@@ -93,57 +126,76 @@ public:
     // invocation to the collector. The options in the invocation are reset,
     // which ensures that the compiler won't create new dependency collectors,
     // and thus won't write out the extra '.d' files to disk.
-    auto Opts = llvm::make_unique<DependencyOutputOptions>(
+    auto Opts = std::make_unique<DependencyOutputOptions>(
         std::move(Compiler.getInvocation().getDependencyOutputOpts()));
     // We need at least one -MT equivalent for the generator to work.
     if (Opts->Targets.empty())
       Opts->Targets = {"clang-scan-deps dependency"};
-    Compiler.addDependencyCollector(std::make_shared<DependencyPrinter>(
-        std::move(Opts), DependencyFileContents));
+    Compiler.addDependencyCollector(
+        std::make_shared<DependencyConsumerForwarder>(std::move(Opts),
+                                                      Consumer));
 
-    auto Action = llvm::make_unique<PreprocessOnlyAction>();
+    auto Action = std::make_unique<PreprocessOnlyAction>();
     const bool Result = Compiler.ExecuteAction(*Action);
-    FileMgr->clearStatCache();
+    if (!DepFS)
+      FileMgr->clearStatCache();
     return Result;
   }
 
 private:
   StringRef WorkingDirectory;
-  /// The dependency file will be written to this string.
-  std::string &DependencyFileContents;
+  DependencyConsumer &Consumer;
+  llvm::IntrusiveRefCntPtr<DependencyScanningWorkerFilesystem> DepFS;
+  ExcludedPreprocessorDirectiveSkipMapping *PPSkipMappings;
 };
 
 } // end anonymous namespace
 
-DependencyScanningWorker::DependencyScanningWorker() {
+DependencyScanningWorker::DependencyScanningWorker(
+    DependencyScanningService &Service) {
   DiagOpts = new DiagnosticOptions();
   PCHContainerOps = std::make_shared<PCHContainerOperations>();
-  /// FIXME: Use the shared file system from the service for fast scanning
-  /// mode.
-  WorkerFS = new ProxyFileSystemWithoutChdir(llvm::vfs::getRealFileSystem());
+  RealFS = new ProxyFileSystemWithoutChdir(llvm::vfs::getRealFileSystem());
+  if (Service.canSkipExcludedPPRanges())
+    PPSkipMappings =
+        std::make_unique<ExcludedPreprocessorDirectiveSkipMapping>();
+  if (Service.getMode() == ScanningMode::MinimizedSourcePreprocessing)
+    DepFS = new DependencyScanningWorkerFilesystem(
+        Service.getSharedCache(), RealFS, PPSkipMappings.get());
+  if (Service.canReuseFileManager())
+    Files = new FileManager(FileSystemOptions(), RealFS);
 }
 
-llvm::Expected<std::string>
-DependencyScanningWorker::getDependencyFile(const std::string &Input,
-                                            StringRef WorkingDirectory,
-                                            const CompilationDatabase &CDB) {
+static llvm::Error runWithDiags(
+    DiagnosticOptions *DiagOpts,
+    llvm::function_ref<bool(DiagnosticConsumer &DC)> BodyShouldSucceed) {
   // Capture the emitted diagnostics and report them to the client
   // in the case of a failure.
   std::string DiagnosticOutput;
   llvm::raw_string_ostream DiagnosticsOS(DiagnosticOutput);
-  TextDiagnosticPrinter DiagPrinter(DiagnosticsOS, DiagOpts.get());
-
-  WorkerFS->setCurrentWorkingDirectory(WorkingDirectory);
-  tooling::ClangTool Tool(CDB, Input, PCHContainerOps, WorkerFS);
-  Tool.clearArgumentsAdjusters();
-  Tool.setRestoreWorkingDir(false);
-  Tool.setPrintErrorMessage(false);
-  Tool.setDiagnosticConsumer(&DiagPrinter);
-  std::string Output;
-  DependencyScanningAction Action(WorkingDirectory, Output);
-  if (Tool.run(&Action)) {
-    return llvm::make_error<llvm::StringError>(DiagnosticsOS.str(),
-                                               llvm::inconvertibleErrorCode());
-  }
-  return Output;
+  TextDiagnosticPrinter DiagPrinter(DiagnosticsOS, DiagOpts);
+
+  if (BodyShouldSucceed(DiagPrinter))
+    return llvm::Error::success();
+  return llvm::make_error<llvm::StringError>(DiagnosticsOS.str(),
+                                             llvm::inconvertibleErrorCode());
+}
+
+llvm::Error DependencyScanningWorker::computeDependencies(
+    const std::string &Input, StringRef WorkingDirectory,
+    const CompilationDatabase &CDB, DependencyConsumer &Consumer) {
+  RealFS->setCurrentWorkingDirectory(WorkingDirectory);
+  return runWithDiags(DiagOpts.get(), [&](DiagnosticConsumer &DC) {
+    /// Create the tool that uses the underlying file system to ensure that any
+    /// file system requests that are made by the driver do not go through the
+    /// dependency scanning filesystem.
+    tooling::ClangTool Tool(CDB, Input, PCHContainerOps, RealFS, Files);
+    Tool.clearArgumentsAdjusters();
+    Tool.setRestoreWorkingDir(false);
+    Tool.setPrintErrorMessage(false);
+    Tool.setDiagnosticConsumer(&DC);
+    DependencyScanningAction Action(WorkingDirectory, Consumer, DepFS,
+                                    PPSkipMappings.get());
+    return !Tool.run(&Action);
+  });
 }
diff --git a/lib/Tooling/GuessTargetAndModeCompilationDatabase.cpp b/lib/Tooling/GuessTargetAndModeCompilationDatabase.cpp
index ac3faf1b01f9..b6c1c0952aca 100644
--- a/lib/Tooling/GuessTargetAndModeCompilationDatabase.cpp
+++ b/lib/Tooling/GuessTargetAndModeCompilationDatabase.cpp
@@ -50,7 +50,7 @@ private:
 
 std::unique_ptr<CompilationDatabase>
 inferTargetAndDriverMode(std::unique_ptr<CompilationDatabase> Base) {
-  return llvm::make_unique<TargetAndModeAdderDatabase>(std::move(Base));
+  return std::make_unique<TargetAndModeAdderDatabase>(std::move(Base));
 }
 
 } // namespace tooling
diff --git a/lib/Tooling/Inclusions/HeaderIncludes.cpp b/lib/Tooling/Inclusions/HeaderIncludes.cpp
index a7f79c33bc55..e746bbb7f87b 100644
--- a/lib/Tooling/Inclusions/HeaderIncludes.cpp
+++ b/lib/Tooling/Inclusions/HeaderIncludes.cpp
@@ -199,6 +199,20 @@ int IncludeCategoryManager::getIncludePriority(StringRef IncludeName,
   return Ret;
 }
 
+int IncludeCategoryManager::getSortIncludePriority(StringRef IncludeName,
+                                                   bool CheckMainHeader) const {
+  int Ret = INT_MAX;
+  for (unsigned i = 0, e = CategoryRegexs.size(); i != e; ++i)
+    if (CategoryRegexs[i].match(IncludeName)) {
+      Ret = Style.IncludeCategories[i].SortPriority;
+      if (Ret == 0)
+        Ret = Style.IncludeCategories[i].Priority;
+      break;
+    }
+  if (CheckMainHeader && IsMainFile && Ret > 0 && isMainHeader(IncludeName))
+    Ret = 0;
+  return Ret;
+}
 bool IncludeCategoryManager::isMainHeader(StringRef IncludeName) const {
   if (!IncludeName.startswith("\""))
     return false;
diff --git a/lib/Tooling/Inclusions/IncludeStyle.cpp b/lib/Tooling/Inclusions/IncludeStyle.cpp
index c53c82c83630..26dc0b87cf9d 100644
--- a/lib/Tooling/Inclusions/IncludeStyle.cpp
+++ b/lib/Tooling/Inclusions/IncludeStyle.cpp
@@ -17,6 +17,7 @@ void MappingTraits<IncludeStyle::IncludeCategory>::mapping(
     IO &IO, IncludeStyle::IncludeCategory &Category) {
   IO.mapOptional("Regex", Category.Regex);
   IO.mapOptional("Priority", Category.Priority);
+  IO.mapOptional("SortPriority", Category.SortPriority);
 }
 
 void ScalarEnumerationTraits<IncludeStyle::IncludeBlocksStyle>::enumeration(
diff --git a/lib/Tooling/InterpolatingCompilationDatabase.cpp b/lib/Tooling/InterpolatingCompilationDatabase.cpp
index 53c8dd448fd9..59b66abe65e9 100644
--- a/lib/Tooling/InterpolatingCompilationDatabase.cpp
+++ b/lib/Tooling/InterpolatingCompilationDatabase.cpp
@@ -42,9 +42,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "clang/Basic/LangStandard.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/Types.h"
-#include "clang/Frontend/LangStandard.h"
 #include "clang/Tooling/CompilationDatabase.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Optional.h"
@@ -149,17 +149,17 @@ struct TransferableCommand {
     // We parse each argument individually so that we can retain the exact
     // spelling of each argument; re-rendering is lossy for aliased flags.
     // E.g. in CL mode, /W4 maps to -Wall.
-    auto OptTable = clang::driver::createDriverOptTable();
+    auto &OptTable = clang::driver::getDriverOptTable();
     if (!OldArgs.empty())
       Cmd.CommandLine.emplace_back(OldArgs.front());
     for (unsigned Pos = 1; Pos < OldArgs.size();) {
       using namespace driver::options;
 
       const unsigned OldPos = Pos;
-      std::unique_ptr<llvm::opt::Arg> Arg(OptTable->ParseOneArg(
+      std::unique_ptr<llvm::opt::Arg> Arg(OptTable.ParseOneArg(
           ArgList, Pos,
-          /* Include */ClangCLMode ? CoreOption | CLOption : 0,
-          /* Exclude */ClangCLMode ? 0 : CLOption));
+          /* Include */ ClangCLMode ? CoreOption | CLOption : 0,
+          /* Exclude */ ClangCLMode ? 0 : CLOption));
 
       if (!Arg)
         continue;
@@ -249,15 +249,15 @@ private:
   }
 
   // Map the language from the --std flag to that of the -x flag.
-  static types::ID toType(InputKind::Language Lang) {
+  static types::ID toType(Language Lang) {
     switch (Lang) {
-    case InputKind::C:
+    case Language::C:
       return types::TY_C;
-    case InputKind::CXX:
+    case Language::CXX:
       return types::TY_CXX;
-    case InputKind::ObjC:
+    case Language::ObjC:
       return types::TY_ObjC;
-    case InputKind::ObjCXX:
+    case Language::ObjCXX:
       return types::TY_ObjCXX;
     default:
       return types::TY_INVALID;
@@ -297,15 +297,8 @@ private:
   // Try to interpret the argument as '-std='.
   Optional<LangStandard::Kind> tryParseStdArg(const llvm::opt::Arg &Arg) {
     using namespace driver::options;
-    if (Arg.getOption().matches(ClangCLMode ? OPT__SLASH_std : OPT_std_EQ)) {
-      return llvm::StringSwitch<LangStandard::Kind>(Arg.getValue())
-#define LANGSTANDARD(id, name, lang, ...) .Case(name, LangStandard::lang_##id)
-#define LANGSTANDARD_ALIAS(id, alias) .Case(alias, LangStandard::lang_##id)
-#include "clang/Frontend/LangStandards.def"
-#undef LANGSTANDARD_ALIAS
-#undef LANGSTANDARD
-                 .Default(LangStandard::lang_unspecified);
-    }
+    if (Arg.getOption().matches(ClangCLMode ? OPT__SLASH_std : OPT_std_EQ))
+      return LangStandard::getLangKind(Arg.getValue());
     return None;
   }
 };
@@ -544,7 +537,7 @@ private:
 
 std::unique_ptr<CompilationDatabase>
 inferMissingCompileCommands(std::unique_ptr<CompilationDatabase> Inner) {
-  return llvm::make_unique<InterpolatingCompilationDatabase>(std::move(Inner));
+  return std::make_unique<InterpolatingCompilationDatabase>(std::move(Inner));
 }
 
 } // namespace tooling
diff --git a/lib/Tooling/Refactoring.cpp b/lib/Tooling/Refactoring.cpp
index f379a9c3bcf6..d45cd8c57f10 100644
--- a/lib/Tooling/Refactoring.cpp
+++ b/lib/Tooling/Refactoring.cpp
@@ -78,7 +78,10 @@ bool formatAndApplyAllReplacements(
     const std::string &FilePath = FileAndReplaces.first;
     auto &CurReplaces = FileAndReplaces.second;
 
-    const FileEntry *Entry = Files.getFile(FilePath);
+    const FileEntry *Entry = nullptr;
+    if (auto File = Files.getFile(FilePath))
+      Entry = *File;
+
     FileID ID = SM.getOrCreateFileID(Entry, SrcMgr::C_User);
     StringRef Code = SM.getBufferData(ID);
 
diff --git a/lib/Tooling/Refactoring/ASTSelectionRequirements.cpp b/lib/Tooling/Refactoring/ASTSelectionRequirements.cpp
index 14fc66a979ae..7dfd3988d904 100644
--- a/lib/Tooling/Refactoring/ASTSelectionRequirements.cpp
+++ b/lib/Tooling/Refactoring/ASTSelectionRequirements.cpp
@@ -35,7 +35,7 @@ Expected<CodeRangeASTSelection> CodeRangeASTSelectionRequirement::evaluate(
   if (!ASTSelection)
     return ASTSelection.takeError();
   std::unique_ptr<SelectedASTNode> StoredSelection =
-      llvm::make_unique<SelectedASTNode>(std::move(*ASTSelection));
+      std::make_unique<SelectedASTNode>(std::move(*ASTSelection));
   Optional<CodeRangeASTSelection> CodeRange = CodeRangeASTSelection::create(
       Context.getSelectionRange(), *StoredSelection);
   if (!CodeRange)
diff --git a/lib/Tooling/Refactoring/Extract/Extract.cpp b/lib/Tooling/Refactoring/Extract/Extract.cpp
index f5b94a462103..402b56109052 100644
--- a/lib/Tooling/Refactoring/Extract/Extract.cpp
+++ b/lib/Tooling/Refactoring/Extract/Extract.cpp
@@ -13,12 +13,12 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Tooling/Refactoring/Extract/Extract.h"
-#include "SourceExtraction.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/Expr.h"
 #include "clang/AST/ExprObjC.h"
 #include "clang/Rewrite/Core/Rewriter.h"
+#include "clang/Tooling/Refactoring/Extract/SourceExtraction.h"
 
 namespace clang {
 namespace tooling {
diff --git a/lib/Tooling/Refactoring/Extract/SourceExtraction.cpp b/lib/Tooling/Refactoring/Extract/SourceExtraction.cpp
index 533c373e35c4..5d57ecf90a96 100644
--- a/lib/Tooling/Refactoring/Extract/SourceExtraction.cpp
+++ b/lib/Tooling/Refactoring/Extract/SourceExtraction.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "SourceExtraction.h"
+#include "clang/Tooling/Refactoring/Extract/SourceExtraction.h"
 #include "clang/AST/Stmt.h"
 #include "clang/AST/StmtCXX.h"
 #include "clang/AST/StmtObjC.h"
@@ -40,8 +40,12 @@ bool isSemicolonRequiredAfter(const Stmt *S) {
     return isSemicolonRequiredAfter(CXXFor->getBody());
   if (const auto *ObjCFor = dyn_cast<ObjCForCollectionStmt>(S))
     return isSemicolonRequiredAfter(ObjCFor->getBody());
+  if(const auto *Switch = dyn_cast<SwitchStmt>(S))
+    return isSemicolonRequiredAfter(Switch->getBody());
+  if(const auto *Case = dyn_cast<SwitchCase>(S))
+    return isSemicolonRequiredAfter(Case->getSubStmt());
   switch (S->getStmtClass()) {
-  case Stmt::SwitchStmtClass:
+  case Stmt::DeclStmtClass:
   case Stmt::CXXTryStmtClass:
   case Stmt::ObjCAtSynchronizedStmtClass:
   case Stmt::ObjCAutoreleasePoolStmtClass:
diff --git a/lib/Tooling/Refactoring/Extract/SourceExtraction.h b/lib/Tooling/Refactoring/Extract/SourceExtraction.h
deleted file mode 100644
index 545eb6c1a11c..000000000000
--- a/lib/Tooling/Refactoring/Extract/SourceExtraction.h
+++ /dev/null
@@ -1,51 +0,0 @@
-//===--- SourceExtraction.cpp - Clang refactoring library -----------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_CLANG_LIB_TOOLING_REFACTORING_EXTRACT_SOURCE_EXTRACTION_H
-#define LLVM_CLANG_LIB_TOOLING_REFACTORING_EXTRACT_SOURCE_EXTRACTION_H
-
-#include "clang/Basic/LLVM.h"
-
-namespace clang {
-
-class LangOptions;
-class SourceManager;
-class SourceRange;
-class Stmt;
-
-namespace tooling {
-
-/// Determines which semicolons should be inserted during extraction.
-class ExtractionSemicolonPolicy {
-public:
-  bool isNeededInExtractedFunction() const {
-    return IsNeededInExtractedFunction;
-  }
-
-  bool isNeededInOriginalFunction() const { return IsNeededInOriginalFunction; }
-
-  /// Returns the semicolon insertion policy that is needed for extraction of
-  /// the given statement from the given source range.
-  static ExtractionSemicolonPolicy compute(const Stmt *S,
-                                           SourceRange &ExtractedRange,
-                                           const SourceManager &SM,
-                                           const LangOptions &LangOpts);
-
-private:
-  ExtractionSemicolonPolicy(bool IsNeededInExtractedFunction,
-                            bool IsNeededInOriginalFunction)
-      : IsNeededInExtractedFunction(IsNeededInExtractedFunction),
-        IsNeededInOriginalFunction(IsNeededInOriginalFunction) {}
-  bool IsNeededInExtractedFunction;
-  bool IsNeededInOriginalFunction;
-};
-
-} // end namespace tooling
-} // end namespace clang
-
-#endif // LLVM_CLANG_LIB_TOOLING_REFACTORING_EXTRACT_SOURCE_EXTRACTION_H
diff --git a/lib/Tooling/Refactoring/RefactoringActions.cpp b/lib/Tooling/Refactoring/RefactoringActions.cpp
index 1a3833243ab4..7ac723f67c04 100644
--- a/lib/Tooling/Refactoring/RefactoringActions.cpp
+++ b/lib/Tooling/Refactoring/RefactoringActions.cpp
@@ -98,8 +98,8 @@ public:
 std::vector<std::unique_ptr<RefactoringAction>> createRefactoringActions() {
   std::vector<std::unique_ptr<RefactoringAction>> Actions;
 
-  Actions.push_back(llvm::make_unique<LocalRename>());
-  Actions.push_back(llvm::make_unique<ExtractRefactoring>());
+  Actions.push_back(std::make_unique<LocalRename>());
+  Actions.push_back(std::make_unique<ExtractRefactoring>());
 
   return Actions;
 }
diff --git a/lib/Tooling/Refactoring/Rename/RenamingAction.cpp b/lib/Tooling/Refactoring/Rename/RenamingAction.cpp
index 1649513a077a..b0634912e3fc 100644
--- a/lib/Tooling/Refactoring/Rename/RenamingAction.cpp
+++ b/lib/Tooling/Refactoring/Rename/RenamingAction.cpp
@@ -266,12 +266,12 @@ private:
 };
 
 std::unique_ptr<ASTConsumer> RenamingAction::newASTConsumer() {
-  return llvm::make_unique<RenamingASTConsumer>(NewNames, PrevNames, USRList,
+  return std::make_unique<RenamingASTConsumer>(NewNames, PrevNames, USRList,
                                                 FileToReplaces, PrintLocations);
 }
 
 std::unique_ptr<ASTConsumer> QualifiedRenamingAction::newASTConsumer() {
-  return llvm::make_unique<USRSymbolRenamer>(NewNames, USRList, FileToReplaces);
+  return std::make_unique<USRSymbolRenamer>(NewNames, USRList, FileToReplaces);
 }
 
 } // end namespace tooling
diff --git a/lib/Tooling/Refactoring/Rename/SymbolOccurrences.cpp b/lib/Tooling/Refactoring/Rename/SymbolOccurrences.cpp
index 8cc1ffaf4482..9e69d37e81ad 100644
--- a/lib/Tooling/Refactoring/Rename/SymbolOccurrences.cpp
+++ b/lib/Tooling/Refactoring/Rename/SymbolOccurrences.cpp
@@ -25,7 +25,7 @@ SymbolOccurrence::SymbolOccurrence(const SymbolName &Name, OccurrenceKind Kind,
         Locations[0], Locations[0].getLocWithOffset(NamePieces[0].size()));
     return;
   }
-  MultipleRanges = llvm::make_unique<SourceRange[]>(Locations.size());
+  MultipleRanges = std::make_unique<SourceRange[]>(Locations.size());
   RangeOrNumRanges.setBegin(
       SourceLocation::getFromRawEncoding(Locations.size()));
   for (const auto &Loc : llvm::enumerate(Locations)) {
diff --git a/lib/Tooling/Refactoring/Rename/USRFindingAction.cpp b/lib/Tooling/Refactoring/Rename/USRFindingAction.cpp
index 54c6f3e734b1..e26248f50c29 100644
--- a/lib/Tooling/Refactoring/Rename/USRFindingAction.cpp
+++ b/lib/Tooling/Refactoring/Rename/USRFindingAction.cpp
@@ -102,6 +102,10 @@ public:
 
 private:
   void handleCXXRecordDecl(const CXXRecordDecl *RecordDecl) {
+    if (!RecordDecl->getDefinition()) {
+      USRSet.insert(getUSRForDecl(RecordDecl));
+      return;
+    }
     RecordDecl = RecordDecl->getDefinition();
     if (const auto *ClassTemplateSpecDecl =
             dyn_cast<ClassTemplateSpecializationDecl>(RecordDecl))
@@ -264,7 +268,7 @@ private:
 };
 
 std::unique_ptr<ASTConsumer> USRFindingAction::newASTConsumer() {
-  return llvm::make_unique<NamedDeclFindingConsumer>(
+  return std::make_unique<NamedDeclFindingConsumer>(
       SymbolOffsets, QualifiedNames, SpellingNames, USRList, Force,
       ErrorOccurred);
 }
diff --git a/lib/Tooling/Refactoring/SourceCode.cpp b/lib/Tooling/Refactoring/SourceCode.cpp
deleted file mode 100644
index 3a97e178bbd4..000000000000
--- a/lib/Tooling/Refactoring/SourceCode.cpp
+++ /dev/null
@@ -1,31 +0,0 @@
-//===--- SourceCode.cpp - Source code manipulation routines -----*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-//
-//  This file provides functions that simplify extraction of source code.
-//
-//===----------------------------------------------------------------------===//
-#include "clang/Tooling/Refactoring/SourceCode.h"
-#include "clang/Lex/Lexer.h"
-
-using namespace clang;
-
-StringRef clang::tooling::getText(CharSourceRange Range,
-                                  const ASTContext &Context) {
-  return Lexer::getSourceText(Range, Context.getSourceManager(),
-                              Context.getLangOpts());
-}
-
-CharSourceRange clang::tooling::maybeExtendRange(CharSourceRange Range,
-                                                 tok::TokenKind Next,
-                                                 ASTContext &Context) {
-  Optional<Token> Tok = Lexer::findNextToken(
-      Range.getEnd(), Context.getSourceManager(), Context.getLangOpts());
-  if (!Tok || !Tok->is(Next))
-    return Range;
-  return CharSourceRange::getTokenRange(Range.getBegin(), Tok->getLocation());
-}
diff --git a/lib/Tooling/Refactoring/Stencil.cpp b/lib/Tooling/Refactoring/Stencil.cpp
deleted file mode 100644
index 09eca21c3cef..000000000000
--- a/lib/Tooling/Refactoring/Stencil.cpp
+++ /dev/null
@@ -1,175 +0,0 @@
-//===--- Stencil.cpp - Stencil implementation -------------------*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "clang/Tooling/Refactoring/Stencil.h"
-#include "clang/AST/ASTContext.h"
-#include "clang/AST/ASTTypeTraits.h"
-#include "clang/AST/Expr.h"
-#include "clang/ASTMatchers/ASTMatchFinder.h"
-#include "clang/ASTMatchers/ASTMatchers.h"
-#include "clang/Lex/Lexer.h"
-#include "clang/Tooling/Refactoring/SourceCode.h"
-#include "llvm/Support/Errc.h"
-#include <atomic>
-#include <memory>
-#include <string>
-
-using namespace clang;
-using namespace tooling;
-
-using ast_matchers::MatchFinder;
-using llvm::Error;
-
-// A down_cast function to safely down cast a StencilPartInterface to a subclass
-// D. Returns nullptr if P is not an instance of D.
-template <typename D> const D *down_cast(const StencilPartInterface *P) {
-  if (P == nullptr || D::typeId() != P->typeId())
-    return nullptr;
-  return static_cast<const D *>(P);
-}
-
-static llvm::Expected<ast_type_traits::DynTypedNode>
-getNode(const ast_matchers::BoundNodes &Nodes, StringRef Id) {
-  auto &NodesMap = Nodes.getMap();
-  auto It = NodesMap.find(Id);
-  if (It == NodesMap.end())
-    return llvm::make_error<llvm::StringError>(llvm::errc::invalid_argument,
-                                               "Id not bound: " + Id);
-  return It->second;
-}
-
-namespace {
-// An arbitrary fragment of code within a stencil.
-struct RawTextData {
-  explicit RawTextData(std::string T) : Text(std::move(T)) {}
-  std::string Text;
-};
-
-// A debugging operation to dump the AST for a particular (bound) AST node.
-struct DebugPrintNodeOpData {
-  explicit DebugPrintNodeOpData(std::string S) : Id(std::move(S)) {}
-  std::string Id;
-};
-
-// The fragment of code corresponding to the selected range.
-struct SelectorOpData {
-  explicit SelectorOpData(RangeSelector S) : Selector(std::move(S)) {}
-  RangeSelector Selector;
-};
-} // namespace
-
-bool isEqualData(const RawTextData &A, const RawTextData &B) {
-  return A.Text == B.Text;
-}
-
-bool isEqualData(const DebugPrintNodeOpData &A, const DebugPrintNodeOpData &B) {
-  return A.Id == B.Id;
-}
-
-// Equality is not (yet) defined for \c RangeSelector.
-bool isEqualData(const SelectorOpData &, const SelectorOpData &) { return false; }
-
-// The `evalData()` overloads evaluate the given stencil data to a string, given
-// the match result, and append it to `Result`. We define an overload for each
-// type of stencil data.
-
-Error evalData(const RawTextData &Data, const MatchFinder::MatchResult &,
-               std::string *Result) {
-  Result->append(Data.Text);
-  return Error::success();
-}
-
-Error evalData(const DebugPrintNodeOpData &Data,
-               const MatchFinder::MatchResult &Match, std::string *Result) {
-  std::string Output;
-  llvm::raw_string_ostream Os(Output);
-  auto NodeOrErr = getNode(Match.Nodes, Data.Id);
-  if (auto Err = NodeOrErr.takeError())
-    return Err;
-  NodeOrErr->print(Os, PrintingPolicy(Match.Context->getLangOpts()));
-  *Result += Os.str();
-  return Error::success();
-}
-
-Error evalData(const SelectorOpData &Data, const MatchFinder::MatchResult &Match,
-               std::string *Result) {
-  auto Range = Data.Selector(Match);
-  if (!Range)
-    return Range.takeError();
-  *Result += getText(*Range, *Match.Context);
-  return Error::success();
-}
-
-template <typename T>
-class StencilPartImpl : public StencilPartInterface {
-  T Data;
-
-public:
-  template <typename... Ps>
-  explicit StencilPartImpl(Ps &&... Args)
-      : StencilPartInterface(StencilPartImpl::typeId()),
-        Data(std::forward<Ps>(Args)...) {}
-
-  // Generates a unique identifier for this class (specifically, one per
-  // instantiation of the template).
-  static const void* typeId() {
-    static bool b;
-    return &b;
-  }
-
-  Error eval(const MatchFinder::MatchResult &Match,
-             std::string *Result) const override {
-    return evalData(Data, Match, Result);
-  }
-
-  bool isEqual(const StencilPartInterface &Other) const override {
-    if (const auto *OtherPtr = down_cast<StencilPartImpl>(&Other))
-      return isEqualData(Data, OtherPtr->Data);
-    return false;
-  }
-};
-
-namespace {
-using RawText = StencilPartImpl<RawTextData>;
-using DebugPrintNodeOp = StencilPartImpl<DebugPrintNodeOpData>;
-using SelectorOp = StencilPartImpl<SelectorOpData>;
-} // namespace
-
-StencilPart Stencil::wrap(StringRef Text) {
-  return stencil::text(Text);
-}
-
-StencilPart Stencil::wrap(RangeSelector Selector) {
-  return stencil::selection(std::move(Selector));
-}
-
-void Stencil::append(Stencil OtherStencil) {
-  for (auto &Part : OtherStencil.Parts)
-    Parts.push_back(std::move(Part));
-}
-
-llvm::Expected<std::string>
-Stencil::eval(const MatchFinder::MatchResult &Match) const {
-  std::string Result;
-  for (const auto &Part : Parts)
-    if (auto Err = Part.eval(Match, &Result))
-      return std::move(Err);
-  return Result;
-}
-
-StencilPart stencil::text(StringRef Text) {
-  return StencilPart(std::make_shared<RawText>(Text));
-}
-
-StencilPart stencil::selection(RangeSelector Selector) {
-  return StencilPart(std::make_shared<SelectorOp>(std::move(Selector)));
-}
-
-StencilPart stencil::dPrint(StringRef Id) {
-  return StencilPart(std::make_shared<DebugPrintNodeOp>(Id));
-}
diff --git a/lib/Tooling/Refactoring/Transformer.cpp b/lib/Tooling/Refactoring/Transformer.cpp
deleted file mode 100644
index 8e6fe6c7a940..000000000000
--- a/lib/Tooling/Refactoring/Transformer.cpp
+++ /dev/null
@@ -1,263 +0,0 @@
-//===--- Transformer.cpp - Transformer library implementation ---*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "clang/Tooling/Refactoring/Transformer.h"
-#include "clang/AST/Expr.h"
-#include "clang/ASTMatchers/ASTMatchFinder.h"
-#include "clang/ASTMatchers/ASTMatchers.h"
-#include "clang/Basic/Diagnostic.h"
-#include "clang/Basic/SourceLocation.h"
-#include "clang/Rewrite/Core/Rewriter.h"
-#include "clang/Tooling/Refactoring/AtomicChange.h"
-#include "clang/Tooling/Refactoring/SourceCode.h"
-#include "llvm/ADT/Optional.h"
-#include "llvm/ADT/StringRef.h"
-#include "llvm/Support/Errc.h"
-#include "llvm/Support/Error.h"
-#include <deque>
-#include <string>
-#include <utility>
-#include <vector>
-
-using namespace clang;
-using namespace tooling;
-
-using ast_matchers::MatchFinder;
-using ast_matchers::internal::DynTypedMatcher;
-using ast_type_traits::ASTNodeKind;
-using ast_type_traits::DynTypedNode;
-using llvm::Error;
-using llvm::StringError;
-
-using MatchResult = MatchFinder::MatchResult;
-
-// Did the text at this location originate in a macro definition (aka. body)?
-// For example,
-//
-//   #define NESTED(x) x
-//   #define MACRO(y) { int y  = NESTED(3); }
-//   if (true) MACRO(foo)
-//
-// The if statement expands to
-//
-//   if (true) { int foo = 3; }
-//                   ^     ^
-//                   Loc1  Loc2
-//
-// For SourceManager SM, SM.isMacroArgExpansion(Loc1) and
-// SM.isMacroArgExpansion(Loc2) are both true, but isOriginMacroBody(sm, Loc1)
-// is false, because "foo" originated in the source file (as an argument to a
-// macro), whereas isOriginMacroBody(SM, Loc2) is true, because "3" originated
-// in the definition of MACRO.
-static bool isOriginMacroBody(const clang::SourceManager &SM,
-                              clang::SourceLocation Loc) {
-  while (Loc.isMacroID()) {
-    if (SM.isMacroBodyExpansion(Loc))
-      return true;
-    // Otherwise, it must be in an argument, so we continue searching up the
-    // invocation stack. getImmediateMacroCallerLoc() gives the location of the
-    // argument text, inside the call text.
-    Loc = SM.getImmediateMacroCallerLoc(Loc);
-  }
-  return false;
-}
-
-Expected<SmallVector<tooling::detail::Transformation, 1>>
-tooling::detail::translateEdits(const MatchResult &Result,
-                                llvm::ArrayRef<ASTEdit> Edits) {
-  SmallVector<tooling::detail::Transformation, 1> Transformations;
-  for (const auto &Edit : Edits) {
-    Expected<CharSourceRange> Range = Edit.TargetRange(Result);
-    if (!Range)
-      return Range.takeError();
-    if (Range->isInvalid() ||
-        isOriginMacroBody(*Result.SourceManager, Range->getBegin()))
-      return SmallVector<Transformation, 0>();
-    auto Replacement = Edit.Replacement(Result);
-    if (!Replacement)
-      return Replacement.takeError();
-    tooling::detail::Transformation T;
-    T.Range = *Range;
-    T.Replacement = std::move(*Replacement);
-    Transformations.push_back(std::move(T));
-  }
-  return Transformations;
-}
-
-ASTEdit tooling::change(RangeSelector S, TextGenerator Replacement) {
-  ASTEdit E;
-  E.TargetRange = std::move(S);
-  E.Replacement = std::move(Replacement);
-  return E;
-}
-
-RewriteRule tooling::makeRule(DynTypedMatcher M, SmallVector<ASTEdit, 1> Edits,
-                              TextGenerator Explanation) {
-  return RewriteRule{{RewriteRule::Case{
-      std::move(M), std::move(Edits), std::move(Explanation), {}}}};
-}
-
-void tooling::addInclude(RewriteRule &Rule, StringRef Header,
-                         IncludeFormat Format) {
-  for (auto &Case : Rule.Cases)
-    Case.AddedIncludes.emplace_back(Header.str(), Format);
-}
-
-// Determines whether A is a base type of B in the class hierarchy, including
-// the implicit relationship of Type and QualType.
-static bool isBaseOf(ASTNodeKind A, ASTNodeKind B) {
-  static auto TypeKind = ASTNodeKind::getFromNodeKind<Type>();
-  static auto QualKind = ASTNodeKind::getFromNodeKind<QualType>();
-  /// Mimic the implicit conversions of Matcher<>.
-  /// - From Matcher<Type> to Matcher<QualType>
-  /// - From Matcher<Base> to Matcher<Derived>
-  return (A.isSame(TypeKind) && B.isSame(QualKind)) || A.isBaseOf(B);
-}
-
-// Try to find a common kind to which all of the rule's matchers can be
-// converted.
-static ASTNodeKind
-findCommonKind(const SmallVectorImpl<RewriteRule::Case> &Cases) {
-  assert(!Cases.empty() && "Rule must have at least one case.");
-  ASTNodeKind JoinKind = Cases[0].Matcher.getSupportedKind();
-  // Find a (least) Kind K, for which M.canConvertTo(K) holds, for all matchers
-  // M in Rules.
-  for (const auto &Case : Cases) {
-    auto K = Case.Matcher.getSupportedKind();
-    if (isBaseOf(JoinKind, K)) {
-      JoinKind = K;
-      continue;
-    }
-    if (K.isSame(JoinKind) || isBaseOf(K, JoinKind))
-      // JoinKind is already the lowest.
-      continue;
-    // K and JoinKind are unrelated -- there is no least common kind.
-    return ASTNodeKind();
-  }
-  return JoinKind;
-}
-
-// Binds each rule's matcher to a unique (and deterministic) tag based on
-// `TagBase`.
-static std::vector<DynTypedMatcher>
-taggedMatchers(StringRef TagBase,
-               const SmallVectorImpl<RewriteRule::Case> &Cases) {
-  std::vector<DynTypedMatcher> Matchers;
-  Matchers.reserve(Cases.size());
-  size_t count = 0;
-  for (const auto &Case : Cases) {
-    std::string Tag = (TagBase + Twine(count)).str();
-    ++count;
-    auto M = Case.Matcher.tryBind(Tag);
-    assert(M && "RewriteRule matchers should be bindable.");
-    Matchers.push_back(*std::move(M));
-  }
-  return Matchers;
-}
-
-// Simply gathers the contents of the various rules into a single rule. The
-// actual work to combine these into an ordered choice is deferred to matcher
-// registration.
-RewriteRule tooling::applyFirst(ArrayRef<RewriteRule> Rules) {
-  RewriteRule R;
-  for (auto &Rule : Rules)
-    R.Cases.append(Rule.Cases.begin(), Rule.Cases.end());
-  return R;
-}
-
-static DynTypedMatcher joinCaseMatchers(const RewriteRule &Rule) {
-  assert(!Rule.Cases.empty() && "Rule must have at least one case.");
-  if (Rule.Cases.size() == 1)
-    return Rule.Cases[0].Matcher;
-
-  auto CommonKind = findCommonKind(Rule.Cases);
-  assert(!CommonKind.isNone() && "Cases must have compatible matchers.");
-  return DynTypedMatcher::constructVariadic(
-      DynTypedMatcher::VO_AnyOf, CommonKind, taggedMatchers("Tag", Rule.Cases));
-}
-
-DynTypedMatcher tooling::detail::buildMatcher(const RewriteRule &Rule) {
-  DynTypedMatcher M = joinCaseMatchers(Rule);
-  M.setAllowBind(true);
-  // `tryBind` is guaranteed to succeed, because `AllowBind` was set to true.
-  return *M.tryBind(RewriteRule::RootID);
-}
-
-// Finds the case that was "selected" -- that is, whose matcher triggered the
-// `MatchResult`.
-const RewriteRule::Case &
-tooling::detail::findSelectedCase(const MatchResult &Result,
-                                  const RewriteRule &Rule) {
-  if (Rule.Cases.size() == 1)
-    return Rule.Cases[0];
-
-  auto &NodesMap = Result.Nodes.getMap();
-  for (size_t i = 0, N = Rule.Cases.size(); i < N; ++i) {
-    std::string Tag = ("Tag" + Twine(i)).str();
-    if (NodesMap.find(Tag) != NodesMap.end())
-      return Rule.Cases[i];
-  }
-  llvm_unreachable("No tag found for this rule.");
-}
-
-constexpr llvm::StringLiteral RewriteRule::RootID;
-
-void Transformer::registerMatchers(MatchFinder *MatchFinder) {
-  MatchFinder->addDynamicMatcher(tooling::detail::buildMatcher(Rule), this);
-}
-
-void Transformer::run(const MatchResult &Result) {
-  if (Result.Context->getDiagnostics().hasErrorOccurred())
-    return;
-
-  // Verify the existence and validity of the AST node that roots this rule.
-  auto &NodesMap = Result.Nodes.getMap();
-  auto Root = NodesMap.find(RewriteRule::RootID);
-  assert(Root != NodesMap.end() && "Transformation failed: missing root node.");
-  SourceLocation RootLoc = Result.SourceManager->getExpansionLoc(
-      Root->second.getSourceRange().getBegin());
-  assert(RootLoc.isValid() && "Invalid location for Root node of match.");
-
-  RewriteRule::Case Case = tooling::detail::findSelectedCase(Result, Rule);
-  auto Transformations = tooling::detail::translateEdits(Result, Case.Edits);
-  if (!Transformations) {
-    Consumer(Transformations.takeError());
-    return;
-  }
-
-  if (Transformations->empty()) {
-    // No rewrite applied (but no error encountered either).
-    RootLoc.print(llvm::errs() << "note: skipping match at loc ",
-                  *Result.SourceManager);
-    llvm::errs() << "\n";
-    return;
-  }
-
-  // Record the results in the AtomicChange.
-  AtomicChange AC(*Result.SourceManager, RootLoc);
-  for (const auto &T : *Transformations) {
-    if (auto Err = AC.replace(*Result.SourceManager, T.Range, T.Replacement)) {
-      Consumer(std::move(Err));
-      return;
-    }
-  }
-
-  for (const auto &I : Case.AddedIncludes) {
-    auto &Header = I.first;
-    switch (I.second) {
-      case IncludeFormat::Quoted:
-        AC.addHeader(Header);
-        break;
-      case IncludeFormat::Angled:
-        AC.addHeader((llvm::Twine("<") + Header + ">").str());
-        break;
-    }
-  }
-
-  Consumer(std::move(AC));
-}
diff --git a/lib/Tooling/RefactoringCallbacks.cpp b/lib/Tooling/RefactoringCallbacks.cpp
index 2aa5b5bf9d98..919b83beb357 100644
--- a/lib/Tooling/RefactoringCallbacks.cpp
+++ b/lib/Tooling/RefactoringCallbacks.cpp
@@ -66,7 +66,7 @@ private:
 };
 
 std::unique_ptr<ASTConsumer> ASTMatchRefactorer::newASTConsumer() {
-  return llvm::make_unique<RefactoringASTConsumer>(*this);
+  return std::make_unique<RefactoringASTConsumer>(*this);
 }
 
 static Replacement replaceStmtWithText(SourceManager &Sources, const Stmt &From,
diff --git a/lib/Tooling/StandaloneExecution.cpp b/lib/Tooling/StandaloneExecution.cpp
index ad82ee083a40..09094c3c23f3 100644
--- a/lib/Tooling/StandaloneExecution.cpp
+++ b/lib/Tooling/StandaloneExecution.cpp
@@ -76,7 +76,7 @@ public:
     if (OptionsParser.getSourcePathList().empty())
       return make_string_error(
           "[StandaloneToolExecutorPlugin] No positional argument found.");
-    return llvm::make_unique<StandaloneToolExecutor>(std::move(OptionsParser));
+    return std::make_unique<StandaloneToolExecutor>(std::move(OptionsParser));
   }
 };
 
diff --git a/lib/Tooling/Syntax/BuildTree.cpp b/lib/Tooling/Syntax/BuildTree.cpp
index 03c439c59e39..a0b653df133d 100644
--- a/lib/Tooling/Syntax/BuildTree.cpp
+++ b/lib/Tooling/Syntax/BuildTree.cpp
@@ -58,8 +58,11 @@ public:
   /// Finish building the tree and consume the root node.
   syntax::TranslationUnit *finalize() && {
     auto Tokens = Arena.tokenBuffer().expandedTokens();
+    assert(!Tokens.empty());
+    assert(Tokens.back().kind() == tok::eof);
+
     // Build the root of the tree, consuming all the children.
-    Pending.foldChildren(Tokens,
+    Pending.foldChildren(Tokens.drop_back(),
                          new (Arena.allocator()) syntax::TranslationUnit);
 
     return cast<syntax::TranslationUnit>(std::move(Pending).finalize());
@@ -96,10 +99,11 @@ private:
   /// Ensures that added nodes properly nest and cover the whole token stream.
   struct Forest {
     Forest(syntax::Arena &A) {
-      // FIXME: do not add 'eof' to the tree.
-
+      assert(!A.tokenBuffer().expandedTokens().empty());
+      assert(A.tokenBuffer().expandedTokens().back().kind() == tok::eof);
       // Create all leaf nodes.
-      for (auto &T : A.tokenBuffer().expandedTokens())
+      // Note that we do not have 'eof' in the tree.
+      for (auto &T : A.tokenBuffer().expandedTokens().drop_back())
         Trees.insert(Trees.end(),
                      {&T, NodeAndRole{new (A.allocator()) syntax::Leaf(&T)}});
     }
diff --git a/lib/Tooling/Syntax/Tokens.cpp b/lib/Tooling/Syntax/Tokens.cpp
index d82dc1f35c94..a2c3bc137d6b 100644
--- a/lib/Tooling/Syntax/Tokens.cpp
+++ b/lib/Tooling/Syntax/Tokens.cpp
@@ -232,6 +232,21 @@ TokenBuffer::expansionStartingAt(const syntax::Token *Spelled) const {
   return E;
 }
 
+std::vector<const syntax::Token *>
+TokenBuffer::macroExpansions(FileID FID) const {
+  auto FileIt = Files.find(FID);
+  assert(FileIt != Files.end() && "file not tracked by token buffer");
+  auto &File = FileIt->second;
+  std::vector<const syntax::Token *> Expansions;
+  auto &Spelled = File.SpelledTokens;
+  for (auto Mapping : File.Mappings) {
+    const syntax::Token *Token = &Spelled[Mapping.BeginSpelled];
+    if (Token->kind() == tok::TokenKind::identifier)
+      Expansions.push_back(Token);
+  }
+  return Expansions;
+}
+
 std::vector<syntax::Token> syntax::tokenize(FileID FID, const SourceManager &SM,
                                             const LangOptions &LO) {
   std::vector<syntax::Token> Tokens;
@@ -321,7 +336,7 @@ TokenCollector::TokenCollector(Preprocessor &PP) : PP(PP) {
   });
   // And locations of macro calls, to properly recover boundaries of those in
   // case of empty expansions.
-  auto CB = llvm::make_unique<CollectPPExpansions>(*this);
+  auto CB = std::make_unique<CollectPPExpansions>(*this);
   this->Collector = CB.get();
   PP.addPPCallbacks(std::move(CB));
 }
diff --git a/lib/Tooling/Tooling.cpp b/lib/Tooling/Tooling.cpp
index 291df0ae333d..1d6a968331b5 100644
--- a/lib/Tooling/Tooling.cpp
+++ b/lib/Tooling/Tooling.cpp
@@ -91,7 +91,34 @@ static const llvm::opt::ArgStringList *getCC1Arguments(
   // We expect to get back exactly one Command job, if we didn't something
   // failed. Extract that job from the Compilation.
   const driver::JobList &Jobs = Compilation->getJobs();
-  if (Jobs.size() != 1 || !isa<driver::Command>(*Jobs.begin())) {
+  const driver::ActionList &Actions = Compilation->getActions();
+  bool OffloadCompilation = false;
+  if (Jobs.size() > 1) {
+    for (auto A : Actions){
+      // On MacOSX real actions may end up being wrapped in BindArchAction
+      if (isa<driver::BindArchAction>(A))
+        A = *A->input_begin();
+      if (isa<driver::OffloadAction>(A)) {
+        // Offload compilation has 2 top-level actions, one (at the front) is
+        // the original host compilation and the other is offload action
+        // composed of at least one device compilation. For such case, general
+        // tooling will consider host-compilation only. For tooling on device
+        // compilation, device compilation only option, such as
+        // `--cuda-device-only`, needs specifying.
+        assert(Actions.size() > 1);
+        assert(
+            isa<driver::CompileJobAction>(Actions.front()) ||
+            // On MacOSX real actions may end up being wrapped in
+            // BindArchAction.
+            (isa<driver::BindArchAction>(Actions.front()) &&
+             isa<driver::CompileJobAction>(*Actions.front()->input_begin())));
+        OffloadCompilation = true;
+        break;
+      }
+    }
+  }
+  if (Jobs.size() == 0 || !isa<driver::Command>(*Jobs.begin()) ||
+      (Jobs.size() > 1 && !OffloadCompilation)) {
     SmallString<256> error_msg;
     llvm::raw_svector_ostream error_stream(error_msg);
     Jobs.Print(error_stream, "; ", true);
@@ -118,20 +145,18 @@ CompilerInvocation *newInvocation(
     DiagnosticsEngine *Diagnostics, const llvm::opt::ArgStringList &CC1Args) {
   assert(!CC1Args.empty() && "Must at least contain the program name!");
   CompilerInvocation *Invocation = new CompilerInvocation;
-  CompilerInvocation::CreateFromArgs(
-      *Invocation, CC1Args.data() + 1, CC1Args.data() + CC1Args.size(),
-      *Diagnostics);
+  CompilerInvocation::CreateFromArgs(*Invocation, CC1Args, *Diagnostics);
   Invocation->getFrontendOpts().DisableFree = false;
   Invocation->getCodeGenOpts().DisableFree = false;
   return Invocation;
 }
 
-bool runToolOnCode(FrontendAction *ToolAction, const Twine &Code,
-                   const Twine &FileName,
+bool runToolOnCode(std::unique_ptr<FrontendAction> ToolAction,
+                   const Twine &Code, const Twine &FileName,
                    std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
-  return runToolOnCodeWithArgs(ToolAction, Code, std::vector<std::string>(),
-                               FileName, "clang-tool",
-                               std::move(PCHContainerOps));
+  return runToolOnCodeWithArgs(std::move(ToolAction), Code,
+                               std::vector<std::string>(), FileName,
+                               "clang-tool", std::move(PCHContainerOps));
 }
 
 } // namespace tooling
@@ -153,7 +178,7 @@ namespace clang {
 namespace tooling {
 
 bool runToolOnCodeWithArgs(
-    FrontendAction *ToolAction, const Twine &Code,
+    std::unique_ptr<FrontendAction> ToolAction, const Twine &Code,
     llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
     const std::vector<std::string> &Args, const Twine &FileName,
     const Twine &ToolName,
@@ -166,13 +191,12 @@ bool runToolOnCodeWithArgs(
   ArgumentsAdjuster Adjuster = getClangStripDependencyFileAdjuster();
   ToolInvocation Invocation(
       getSyntaxOnlyToolArgs(ToolName, Adjuster(Args, FileNameRef), FileNameRef),
-      ToolAction, Files.get(),
-      std::move(PCHContainerOps));
+      std::move(ToolAction), Files.get(), std::move(PCHContainerOps));
   return Invocation.run();
 }
 
 bool runToolOnCodeWithArgs(
-    FrontendAction *ToolAction, const Twine &Code,
+    std::unique_ptr<FrontendAction> ToolAction, const Twine &Code,
     const std::vector<std::string> &Args, const Twine &FileName,
     const Twine &ToolName,
     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
@@ -194,8 +218,8 @@ bool runToolOnCodeWithArgs(
         llvm::MemoryBuffer::getMemBuffer(FilenameWithContent.second));
   }
 
-  return runToolOnCodeWithArgs(ToolAction, Code, OverlayFileSystem, Args,
-                               FileName, ToolName);
+  return runToolOnCodeWithArgs(std::move(ToolAction), Code, OverlayFileSystem,
+                               Args, FileName, ToolName);
 }
 
 llvm::Expected<std::string> getAbsolutePath(llvm::vfs::FileSystem &FS,
@@ -249,12 +273,15 @@ void addTargetAndModeForProgramName(std::vector<std::string> &CommandLine,
 namespace {
 
 class SingleFrontendActionFactory : public FrontendActionFactory {
-  FrontendAction *Action;
+  std::unique_ptr<FrontendAction> Action;
 
 public:
-  SingleFrontendActionFactory(FrontendAction *Action) : Action(Action) {}
+  SingleFrontendActionFactory(std::unique_ptr<FrontendAction> Action)
+      : Action(std::move(Action)) {}
 
-  FrontendAction *create() override { return Action; }
+  std::unique_ptr<FrontendAction> create() override {
+    return std::move(Action);
+  }
 };
 
 } // namespace
@@ -266,11 +293,13 @@ ToolInvocation::ToolInvocation(
       Files(Files), PCHContainerOps(std::move(PCHContainerOps)) {}
 
 ToolInvocation::ToolInvocation(
-    std::vector<std::string> CommandLine, FrontendAction *FAction,
-    FileManager *Files, std::shared_ptr<PCHContainerOperations> PCHContainerOps)
+    std::vector<std::string> CommandLine,
+    std::unique_ptr<FrontendAction> FAction, FileManager *Files,
+    std::shared_ptr<PCHContainerOperations> PCHContainerOps)
     : CommandLine(std::move(CommandLine)),
-      Action(new SingleFrontendActionFactory(FAction)), OwnsAction(true),
-      Files(Files), PCHContainerOps(std::move(PCHContainerOps)) {}
+      Action(new SingleFrontendActionFactory(std::move(FAction))),
+      OwnsAction(true), Files(Files),
+      PCHContainerOps(std::move(PCHContainerOps)) {}
 
 ToolInvocation::~ToolInvocation() {
   if (OwnsAction)
@@ -290,8 +319,7 @@ bool ToolInvocation::run() {
   const char *const BinaryName = Argv[0];
   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
   unsigned MissingArgIndex, MissingArgCount;
-  std::unique_ptr<llvm::opt::OptTable> Opts = driver::createDriverOptTable();
-  llvm::opt::InputArgList ParsedArgs = Opts->ParseArgs(
+  llvm::opt::InputArgList ParsedArgs = driver::getDriverOptTable().ParseArgs(
       ArrayRef<const char *>(Argv).slice(1), MissingArgIndex, MissingArgCount);
   ParseDiagnosticArgs(*DiagOpts, ParsedArgs);
   TextDiagnosticPrinter DiagnosticPrinter(
@@ -375,16 +403,20 @@ bool FrontendActionFactory::runInvocation(
 ClangTool::ClangTool(const CompilationDatabase &Compilations,
                      ArrayRef<std::string> SourcePaths,
                      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
-                     IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS)
+                     IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS,
+                     IntrusiveRefCntPtr<FileManager> Files)
     : Compilations(Compilations), SourcePaths(SourcePaths),
       PCHContainerOps(std::move(PCHContainerOps)),
       OverlayFileSystem(new llvm::vfs::OverlayFileSystem(std::move(BaseFS))),
       InMemoryFileSystem(new llvm::vfs::InMemoryFileSystem),
-      Files(new FileManager(FileSystemOptions(), OverlayFileSystem)) {
+      Files(Files ? Files
+                  : new FileManager(FileSystemOptions(), OverlayFileSystem)) {
   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
   appendArgumentsAdjuster(getClangStripOutputAdjuster());
   appendArgumentsAdjuster(getClangSyntaxOnlyAdjuster());
   appendArgumentsAdjuster(getClangStripDependencyFileAdjuster());
+  if (Files)
+    Files->setVirtualFileSystem(OverlayFileSystem);
 }
 
 ClangTool::~ClangTool() = default;
diff --git a/lib/Tooling/Transformer/CMakeLists.txt b/lib/Tooling/Transformer/CMakeLists.txt
new file mode 100644
index 000000000000..68f0cfeee8f6
--- /dev/null
+++ b/lib/Tooling/Transformer/CMakeLists.txt
@@ -0,0 +1,18 @@
+set(LLVM_LINK_COMPONENTS Support)
+
+add_clang_library(clangTransformer
+  RangeSelector.cpp
+  RewriteRule.cpp
+  SourceCode.cpp
+  SourceCodeBuilders.cpp
+  Stencil.cpp
+  Transformer.cpp
+
+  LINK_LIBS
+  clangAST
+  clangASTMatchers
+  clangBasic
+  clangLex
+  clangToolingCore
+  clangToolingRefactoring
+  )
diff --git a/lib/Tooling/Refactoring/RangeSelector.cpp b/lib/Tooling/Transformer/RangeSelector.cpp
index 768c02e2277b..9f81423c9022 100644
--- a/lib/Tooling/Refactoring/RangeSelector.cpp
+++ b/lib/Tooling/Transformer/RangeSelector.cpp
@@ -6,12 +6,12 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "clang/Tooling/Refactoring/RangeSelector.h"
+#include "clang/Tooling/Transformer/RangeSelector.h"
 #include "clang/AST/Expr.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Lex/Lexer.h"
-#include "clang/Tooling/Refactoring/SourceCode.h"
+#include "clang/Tooling/Transformer/SourceCode.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/Error.h"
@@ -20,7 +20,7 @@
 #include <vector>
 
 using namespace clang;
-using namespace tooling;
+using namespace transformer;
 
 using ast_matchers::MatchFinder;
 using ast_type_traits::ASTNodeKind;
@@ -104,7 +104,7 @@ static SourceLocation findOpenParen(const CallExpr &E, const SourceManager &SM,
   return findPreviousTokenKind(EndLoc, SM, LangOpts, tok::TokenKind::l_paren);
 }
 
-RangeSelector tooling::before(RangeSelector Selector) {
+RangeSelector transformer::before(RangeSelector Selector) {
   return [Selector](const MatchResult &Result) -> Expected<CharSourceRange> {
     Expected<CharSourceRange> SelectedRange = Selector(Result);
     if (!SelectedRange)
@@ -113,7 +113,7 @@ RangeSelector tooling::before(RangeSelector Selector) {
   };
 }
 
-RangeSelector tooling::after(RangeSelector Selector) {
+RangeSelector transformer::after(RangeSelector Selector) {
   return [Selector](const MatchResult &Result) -> Expected<CharSourceRange> {
     Expected<CharSourceRange> SelectedRange = Selector(Result);
     if (!SelectedRange)
@@ -126,27 +126,29 @@ RangeSelector tooling::after(RangeSelector Selector) {
   };
 }
 
-RangeSelector tooling::node(std::string ID) {
+RangeSelector transformer::node(std::string ID) {
   return [ID](const MatchResult &Result) -> Expected<CharSourceRange> {
     Expected<DynTypedNode> Node = getNode(Result.Nodes, ID);
     if (!Node)
       return Node.takeError();
     return Node->get<Stmt>() != nullptr && Node->get<Expr>() == nullptr
-               ? getExtendedRange(*Node, tok::TokenKind::semi, *Result.Context)
+               ? tooling::getExtendedRange(*Node, tok::TokenKind::semi,
+                                           *Result.Context)
                : CharSourceRange::getTokenRange(Node->getSourceRange());
   };
 }
 
-RangeSelector tooling::statement(std::string ID) {
+RangeSelector transformer::statement(std::string ID) {
   return [ID](const MatchResult &Result) -> Expected<CharSourceRange> {
     Expected<DynTypedNode> Node = getNode(Result.Nodes, ID);
     if (!Node)
       return Node.takeError();
-    return getExtendedRange(*Node, tok::TokenKind::semi, *Result.Context);
+    return tooling::getExtendedRange(*Node, tok::TokenKind::semi,
+                                     *Result.Context);
   };
 }
 
-RangeSelector tooling::range(RangeSelector Begin, RangeSelector End) {
+RangeSelector transformer::range(RangeSelector Begin, RangeSelector End) {
   return [Begin, End](const MatchResult &Result) -> Expected<CharSourceRange> {
     Expected<CharSourceRange> BeginRange = Begin(Result);
     if (!BeginRange)
@@ -165,11 +167,11 @@ RangeSelector tooling::range(RangeSelector Begin, RangeSelector End) {
   };
 }
 
-RangeSelector tooling::range(std::string BeginID, std::string EndID) {
-  return tooling::range(node(std::move(BeginID)), node(std::move(EndID)));
+RangeSelector transformer::range(std::string BeginID, std::string EndID) {
+  return transformer::range(node(std::move(BeginID)), node(std::move(EndID)));
 }
 
-RangeSelector tooling::member(std::string ID) {
+RangeSelector transformer::member(std::string ID) {
   return [ID](const MatchResult &Result) -> Expected<CharSourceRange> {
     Expected<DynTypedNode> Node = getNode(Result.Nodes, ID);
     if (!Node)
@@ -181,7 +183,7 @@ RangeSelector tooling::member(std::string ID) {
   };
 }
 
-RangeSelector tooling::name(std::string ID) {
+RangeSelector transformer::name(std::string ID) {
   return [ID](const MatchResult &Result) -> Expected<CharSourceRange> {
     Expected<DynTypedNode> N = getNode(Result.Nodes, ID);
     if (!N)
@@ -197,7 +199,7 @@ RangeSelector tooling::name(std::string ID) {
       // `foo<int>` for which this range will be too short.  Doing so will
       // require subcasing `NamedDecl`, because it doesn't provide virtual
       // access to the \c DeclarationNameInfo.
-      if (getText(R, *Result.Context) != D->getName())
+      if (tooling::getText(R, *Result.Context) != D->getName())
         return CharSourceRange();
       return R;
     }
@@ -219,6 +221,9 @@ RangeSelector tooling::name(std::string ID) {
 }
 
 namespace {
+// FIXME: make this available in the public API for users to easily create their
+// own selectors.
+
 // Creates a selector from a range-selection function \p Func, which selects a
 // range that is relative to a bound node id.  \c T is the node type expected by
 // \p Func.
@@ -253,7 +258,7 @@ CharSourceRange getStatementsRange(const MatchResult &,
 }
 } // namespace
 
-RangeSelector tooling::statements(std::string ID) {
+RangeSelector transformer::statements(std::string ID) {
   return RelativeSelector<CompoundStmt, getStatementsRange>(std::move(ID));
 }
 
@@ -268,7 +273,7 @@ CharSourceRange getCallArgumentsRange(const MatchResult &Result,
 }
 } // namespace
 
-RangeSelector tooling::callArgs(std::string ID) {
+RangeSelector transformer::callArgs(std::string ID) {
   return RelativeSelector<CallExpr, getCallArgumentsRange>(std::move(ID));
 }
 
@@ -282,11 +287,24 @@ CharSourceRange getElementsRange(const MatchResult &,
 }
 } // namespace
 
-RangeSelector tooling::initListElements(std::string ID) {
+RangeSelector transformer::initListElements(std::string ID) {
   return RelativeSelector<InitListExpr, getElementsRange>(std::move(ID));
 }
 
-RangeSelector tooling::expansion(RangeSelector S) {
+namespace {
+// Returns the range of the else branch, including the `else` keyword.
+CharSourceRange getElseRange(const MatchResult &Result, const IfStmt &S) {
+  return tooling::maybeExtendRange(
+      CharSourceRange::getTokenRange(S.getElseLoc(), S.getEndLoc()),
+      tok::TokenKind::semi, *Result.Context);
+}
+} // namespace
+
+RangeSelector transformer::elseBranch(std::string ID) {
+  return RelativeSelector<IfStmt, getElseRange>(std::move(ID));
+}
+
+RangeSelector transformer::expansion(RangeSelector S) {
   return [S](const MatchResult &Result) -> Expected<CharSourceRange> {
     Expected<CharSourceRange> SRange = S(Result);
     if (!SRange)
diff --git a/lib/Tooling/Transformer/RewriteRule.cpp b/lib/Tooling/Transformer/RewriteRule.cpp
new file mode 100644
index 000000000000..6fa558f7b2ee
--- /dev/null
+++ b/lib/Tooling/Transformer/RewriteRule.cpp
@@ -0,0 +1,178 @@
+//===--- Transformer.cpp - Transformer library implementation ---*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/Transformer/RewriteRule.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/Basic/SourceLocation.h"
+#include "clang/Tooling/Transformer/SourceCode.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Errc.h"
+#include "llvm/Support/Error.h"
+#include <map>
+#include <string>
+#include <utility>
+#include <vector>
+
+using namespace clang;
+using namespace transformer;
+
+using ast_matchers::MatchFinder;
+using ast_matchers::internal::DynTypedMatcher;
+using ast_type_traits::ASTNodeKind;
+
+using MatchResult = MatchFinder::MatchResult;
+
+Expected<SmallVector<transformer::detail::Transformation, 1>>
+transformer::detail::translateEdits(const MatchResult &Result,
+                                llvm::ArrayRef<ASTEdit> Edits) {
+  SmallVector<transformer::detail::Transformation, 1> Transformations;
+  for (const auto &Edit : Edits) {
+    Expected<CharSourceRange> Range = Edit.TargetRange(Result);
+    if (!Range)
+      return Range.takeError();
+    llvm::Optional<CharSourceRange> EditRange =
+        tooling::getRangeForEdit(*Range, *Result.Context);
+    // FIXME: let user specify whether to treat this case as an error or ignore
+    // it as is currently done.
+    if (!EditRange)
+      return SmallVector<Transformation, 0>();
+    auto Replacement = Edit.Replacement(Result);
+    if (!Replacement)
+      return Replacement.takeError();
+    transformer::detail::Transformation T;
+    T.Range = *EditRange;
+    T.Replacement = std::move(*Replacement);
+    Transformations.push_back(std::move(T));
+  }
+  return Transformations;
+}
+
+ASTEdit transformer::change(RangeSelector S, TextGenerator Replacement) {
+  ASTEdit E;
+  E.TargetRange = std::move(S);
+  E.Replacement = std::move(Replacement);
+  return E;
+}
+
+RewriteRule transformer::makeRule(DynTypedMatcher M, SmallVector<ASTEdit, 1> Edits,
+                              TextGenerator Explanation) {
+  return RewriteRule{{RewriteRule::Case{
+      std::move(M), std::move(Edits), std::move(Explanation), {}}}};
+}
+
+void transformer::addInclude(RewriteRule &Rule, StringRef Header,
+                         IncludeFormat Format) {
+  for (auto &Case : Rule.Cases)
+    Case.AddedIncludes.emplace_back(Header.str(), Format);
+}
+
+#ifndef NDEBUG
+// Filters for supported matcher kinds. FIXME: Explicitly list the allowed kinds
+// (all node matcher types except for `QualType` and `Type`), rather than just
+// banning `QualType` and `Type`.
+static bool hasValidKind(const DynTypedMatcher &M) {
+  return !M.canConvertTo<QualType>();
+}
+#endif
+
+// Binds each rule's matcher to a unique (and deterministic) tag based on
+// `TagBase` and the id paired with the case.
+static std::vector<DynTypedMatcher> taggedMatchers(
+    StringRef TagBase,
+    const SmallVectorImpl<std::pair<size_t, RewriteRule::Case>> &Cases) {
+  std::vector<DynTypedMatcher> Matchers;
+  Matchers.reserve(Cases.size());
+  for (const auto &Case : Cases) {
+    std::string Tag = (TagBase + Twine(Case.first)).str();
+    // HACK: Many matchers are not bindable, so ensure that tryBind will work.
+    DynTypedMatcher BoundMatcher(Case.second.Matcher);
+    BoundMatcher.setAllowBind(true);
+    auto M = BoundMatcher.tryBind(Tag);
+    Matchers.push_back(*std::move(M));
+  }
+  return Matchers;
+}
+
+// Simply gathers the contents of the various rules into a single rule. The
+// actual work to combine these into an ordered choice is deferred to matcher
+// registration.
+RewriteRule transformer::applyFirst(ArrayRef<RewriteRule> Rules) {
+  RewriteRule R;
+  for (auto &Rule : Rules)
+    R.Cases.append(Rule.Cases.begin(), Rule.Cases.end());
+  return R;
+}
+
+std::vector<DynTypedMatcher>
+transformer::detail::buildMatchers(const RewriteRule &Rule) {
+  // Map the cases into buckets of matchers -- one for each "root" AST kind,
+  // which guarantees that they can be combined in a single anyOf matcher. Each
+  // case is paired with an identifying number that is converted to a string id
+  // in `taggedMatchers`.
+  std::map<ASTNodeKind, SmallVector<std::pair<size_t, RewriteRule::Case>, 1>>
+      Buckets;
+  const SmallVectorImpl<RewriteRule::Case> &Cases = Rule.Cases;
+  for (int I = 0, N = Cases.size(); I < N; ++I) {
+    assert(hasValidKind(Cases[I].Matcher) &&
+           "Matcher must be non-(Qual)Type node matcher");
+    Buckets[Cases[I].Matcher.getSupportedKind()].emplace_back(I, Cases[I]);
+  }
+
+  std::vector<DynTypedMatcher> Matchers;
+  for (const auto &Bucket : Buckets) {
+    DynTypedMatcher M = DynTypedMatcher::constructVariadic(
+        DynTypedMatcher::VO_AnyOf, Bucket.first,
+        taggedMatchers("Tag", Bucket.second));
+    M.setAllowBind(true);
+    // `tryBind` is guaranteed to succeed, because `AllowBind` was set to true.
+    Matchers.push_back(*M.tryBind(RewriteRule::RootID));
+  }
+  return Matchers;
+}
+
+DynTypedMatcher transformer::detail::buildMatcher(const RewriteRule &Rule) {
+  std::vector<DynTypedMatcher> Ms = buildMatchers(Rule);
+  assert(Ms.size() == 1 && "Cases must have compatible matchers.");
+  return Ms[0];
+}
+
+SourceLocation transformer::detail::getRuleMatchLoc(const MatchResult &Result) {
+  auto &NodesMap = Result.Nodes.getMap();
+  auto Root = NodesMap.find(RewriteRule::RootID);
+  assert(Root != NodesMap.end() && "Transformation failed: missing root node.");
+  llvm::Optional<CharSourceRange> RootRange = tooling::getRangeForEdit(
+      CharSourceRange::getTokenRange(Root->second.getSourceRange()),
+      *Result.Context);
+  if (RootRange)
+    return RootRange->getBegin();
+  // The match doesn't have a coherent range, so fall back to the expansion
+  // location as the "beginning" of the match.
+  return Result.SourceManager->getExpansionLoc(
+      Root->second.getSourceRange().getBegin());
+}
+
+// Finds the case that was "selected" -- that is, whose matcher triggered the
+// `MatchResult`.
+const RewriteRule::Case &
+transformer::detail::findSelectedCase(const MatchResult &Result,
+                                  const RewriteRule &Rule) {
+  if (Rule.Cases.size() == 1)
+    return Rule.Cases[0];
+
+  auto &NodesMap = Result.Nodes.getMap();
+  for (size_t i = 0, N = Rule.Cases.size(); i < N; ++i) {
+    std::string Tag = ("Tag" + Twine(i)).str();
+    if (NodesMap.find(Tag) != NodesMap.end())
+      return Rule.Cases[i];
+  }
+  llvm_unreachable("No tag found for this rule.");
+}
+
+constexpr llvm::StringLiteral RewriteRule::RootID;
diff --git a/lib/Tooling/Transformer/SourceCode.cpp b/lib/Tooling/Transformer/SourceCode.cpp
new file mode 100644
index 000000000000..836401d1e605
--- /dev/null
+++ b/lib/Tooling/Transformer/SourceCode.cpp
@@ -0,0 +1,65 @@
+//===--- SourceCode.cpp - Source code manipulation routines -----*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file provides functions that simplify extraction of source code.
+//
+//===----------------------------------------------------------------------===//
+#include "clang/Tooling/Transformer/SourceCode.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang;
+
+StringRef clang::tooling::getText(CharSourceRange Range,
+                                  const ASTContext &Context) {
+  return Lexer::getSourceText(Range, Context.getSourceManager(),
+                              Context.getLangOpts());
+}
+
+CharSourceRange clang::tooling::maybeExtendRange(CharSourceRange Range,
+                                                 tok::TokenKind Next,
+                                                 ASTContext &Context) {
+  Optional<Token> Tok = Lexer::findNextToken(
+      Range.getEnd(), Context.getSourceManager(), Context.getLangOpts());
+  if (!Tok || !Tok->is(Next))
+    return Range;
+  return CharSourceRange::getTokenRange(Range.getBegin(), Tok->getLocation());
+}
+
+llvm::Optional<CharSourceRange>
+clang::tooling::getRangeForEdit(const CharSourceRange &EditRange,
+                                const SourceManager &SM,
+                                const LangOptions &LangOpts) {
+  // FIXME: makeFileCharRange() has the disadvantage of stripping off "identity"
+  // macros. For example, if we're looking to rewrite the int literal 3 to 6,
+  // and we have the following definition:
+  //    #define DO_NOTHING(x) x
+  // then
+  //    foo(DO_NOTHING(3))
+  // will be rewritten to
+  //    foo(6)
+  // rather than the arguably better
+  //    foo(DO_NOTHING(6))
+  // Decide whether the current behavior is desirable and modify if not.
+  CharSourceRange Range = Lexer::makeFileCharRange(EditRange, SM, LangOpts);
+  if (Range.isInvalid())
+    return None;
+
+  if (Range.getBegin().isMacroID() || Range.getEnd().isMacroID())
+    return None;
+  if (SM.isInSystemHeader(Range.getBegin()) ||
+      SM.isInSystemHeader(Range.getEnd()))
+    return None;
+
+  std::pair<FileID, unsigned> BeginInfo = SM.getDecomposedLoc(Range.getBegin());
+  std::pair<FileID, unsigned> EndInfo = SM.getDecomposedLoc(Range.getEnd());
+  if (BeginInfo.first != EndInfo.first ||
+      BeginInfo.second > EndInfo.second)
+    return None;
+
+  return Range;
+}
diff --git a/lib/Tooling/Transformer/SourceCodeBuilders.cpp b/lib/Tooling/Transformer/SourceCodeBuilders.cpp
new file mode 100644
index 000000000000..56ec45e8fd1d
--- /dev/null
+++ b/lib/Tooling/Transformer/SourceCodeBuilders.cpp
@@ -0,0 +1,160 @@
+//===--- SourceCodeBuilder.cpp ----------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/Transformer/SourceCodeBuilders.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/Tooling/Transformer/SourceCode.h"
+#include "llvm/ADT/Twine.h"
+#include <string>
+
+using namespace clang;
+using namespace tooling;
+
+const Expr *tooling::reallyIgnoreImplicit(const Expr &E) {
+  const Expr *Expr = E.IgnoreImplicit();
+  if (const auto *CE = dyn_cast<CXXConstructExpr>(Expr)) {
+    if (CE->getNumArgs() > 0 &&
+        CE->getArg(0)->getSourceRange() == Expr->getSourceRange())
+      return CE->getArg(0)->IgnoreImplicit();
+  }
+  return Expr;
+}
+
+bool tooling::mayEverNeedParens(const Expr &E) {
+  const Expr *Expr = reallyIgnoreImplicit(E);
+  // We always want parens around unary, binary, and ternary operators, because
+  // they are lower precedence.
+  if (isa<UnaryOperator>(Expr) || isa<BinaryOperator>(Expr) ||
+      isa<AbstractConditionalOperator>(Expr))
+    return true;
+
+  // We need parens around calls to all overloaded operators except: function
+  // calls, subscripts, and expressions that are already part of an (implicit)
+  // call to operator->. These latter are all in the same precedence level as
+  // dot/arrow and that level is left associative, so they don't need parens
+  // when appearing on the left.
+  if (const auto *Op = dyn_cast<CXXOperatorCallExpr>(Expr))
+    return Op->getOperator() != OO_Call && Op->getOperator() != OO_Subscript &&
+           Op->getOperator() != OO_Arrow;
+
+  return false;
+}
+
+bool tooling::needParensAfterUnaryOperator(const Expr &E) {
+  const Expr *Expr = reallyIgnoreImplicit(E);
+  if (isa<BinaryOperator>(Expr) || isa<AbstractConditionalOperator>(Expr))
+    return true;
+
+  if (const auto *Op = dyn_cast<CXXOperatorCallExpr>(Expr))
+    return Op->getNumArgs() == 2 && Op->getOperator() != OO_PlusPlus &&
+           Op->getOperator() != OO_MinusMinus && Op->getOperator() != OO_Call &&
+           Op->getOperator() != OO_Subscript;
+
+  return false;
+}
+
+llvm::Optional<std::string> tooling::buildParens(const Expr &E,
+                                                 const ASTContext &Context) {
+  StringRef Text = getText(E, Context);
+  if (Text.empty())
+    return llvm::None;
+  if (mayEverNeedParens(E))
+    return ("(" + Text + ")").str();
+  return Text.str();
+}
+
+llvm::Optional<std::string>
+tooling::buildDereference(const Expr &E, const ASTContext &Context) {
+  if (const auto *Op = dyn_cast<UnaryOperator>(&E))
+    if (Op->getOpcode() == UO_AddrOf) {
+      // Strip leading '&'.
+      StringRef Text =
+          getText(*Op->getSubExpr()->IgnoreParenImpCasts(), Context);
+      if (Text.empty())
+        return llvm::None;
+      return Text.str();
+    }
+
+  StringRef Text = getText(E, Context);
+  if (Text.empty())
+    return llvm::None;
+  // Add leading '*'.
+  if (needParensAfterUnaryOperator(E))
+    return ("*(" + Text + ")").str();
+  return ("*" + Text).str();
+}
+
+llvm::Optional<std::string> tooling::buildAddressOf(const Expr &E,
+                                                    const ASTContext &Context) {
+  if (const auto *Op = dyn_cast<UnaryOperator>(&E))
+    if (Op->getOpcode() == UO_Deref) {
+      // Strip leading '*'.
+      StringRef Text =
+          getText(*Op->getSubExpr()->IgnoreParenImpCasts(), Context);
+      if (Text.empty())
+        return llvm::None;
+      return Text.str();
+    }
+  // Add leading '&'.
+  StringRef Text = getText(E, Context);
+  if (Text.empty())
+    return llvm::None;
+  if (needParensAfterUnaryOperator(E)) {
+    return ("&(" + Text + ")").str();
+  }
+  return ("&" + Text).str();
+}
+
+llvm::Optional<std::string> tooling::buildDot(const Expr &E,
+                                              const ASTContext &Context) {
+  if (const auto *Op = llvm::dyn_cast<UnaryOperator>(&E))
+    if (Op->getOpcode() == UO_Deref) {
+      // Strip leading '*', add following '->'.
+      const Expr *SubExpr = Op->getSubExpr()->IgnoreParenImpCasts();
+      StringRef DerefText = getText(*SubExpr, Context);
+      if (DerefText.empty())
+        return llvm::None;
+      if (needParensBeforeDotOrArrow(*SubExpr))
+        return ("(" + DerefText + ")->").str();
+      return (DerefText + "->").str();
+    }
+
+  // Add following '.'.
+  StringRef Text = getText(E, Context);
+  if (Text.empty())
+    return llvm::None;
+  if (needParensBeforeDotOrArrow(E)) {
+    return ("(" + Text + ").").str();
+  }
+  return (Text + ".").str();
+}
+
+llvm::Optional<std::string> tooling::buildArrow(const Expr &E,
+                                                const ASTContext &Context) {
+  if (const auto *Op = llvm::dyn_cast<UnaryOperator>(&E))
+    if (Op->getOpcode() == UO_AddrOf) {
+      // Strip leading '&', add following '.'.
+      const Expr *SubExpr = Op->getSubExpr()->IgnoreParenImpCasts();
+      StringRef DerefText = getText(*SubExpr, Context);
+      if (DerefText.empty())
+        return llvm::None;
+      if (needParensBeforeDotOrArrow(*SubExpr))
+        return ("(" + DerefText + ").").str();
+      return (DerefText + ".").str();
+    }
+
+  // Add following '->'.
+  StringRef Text = getText(E, Context);
+  if (Text.empty())
+    return llvm::None;
+  if (needParensBeforeDotOrArrow(E))
+    return ("(" + Text + ")->").str();
+  return (Text + "->").str();
+}
diff --git a/lib/Tooling/Transformer/Stencil.cpp b/lib/Tooling/Transformer/Stencil.cpp
new file mode 100644
index 000000000000..984950a54e96
--- /dev/null
+++ b/lib/Tooling/Transformer/Stencil.cpp
@@ -0,0 +1,318 @@
+//===--- Stencil.cpp - Stencil implementation -------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/Transformer/Stencil.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/ASTTypeTraits.h"
+#include "clang/AST/Expr.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Tooling/Transformer/SourceCode.h"
+#include "clang/Tooling/Transformer/SourceCodeBuilders.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Support/Errc.h"
+#include <atomic>
+#include <memory>
+#include <string>
+
+using namespace clang;
+using namespace transformer;
+
+using ast_matchers::MatchFinder;
+using ast_type_traits::DynTypedNode;
+using llvm::errc;
+using llvm::Error;
+using llvm::Expected;
+using llvm::StringError;
+
+static llvm::Expected<DynTypedNode>
+getNode(const ast_matchers::BoundNodes &Nodes, StringRef Id) {
+  auto &NodesMap = Nodes.getMap();
+  auto It = NodesMap.find(Id);
+  if (It == NodesMap.end())
+    return llvm::make_error<llvm::StringError>(llvm::errc::invalid_argument,
+                                               "Id not bound: " + Id);
+  return It->second;
+}
+
+namespace {
+// An arbitrary fragment of code within a stencil.
+struct RawTextData {
+  explicit RawTextData(std::string T) : Text(std::move(T)) {}
+  std::string Text;
+};
+
+// A debugging operation to dump the AST for a particular (bound) AST node.
+struct DebugPrintNodeData {
+  explicit DebugPrintNodeData(std::string S) : Id(std::move(S)) {}
+  std::string Id;
+};
+
+// Operators that take a single node Id as an argument.
+enum class UnaryNodeOperator {
+  Parens,
+  Deref,
+  Address,
+};
+
+// Generic container for stencil operations with a (single) node-id argument.
+struct UnaryOperationData {
+  UnaryOperationData(UnaryNodeOperator Op, std::string Id)
+      : Op(Op), Id(std::move(Id)) {}
+  UnaryNodeOperator Op;
+  std::string Id;
+};
+
+// The fragment of code corresponding to the selected range.
+struct SelectorData {
+  explicit SelectorData(RangeSelector S) : Selector(std::move(S)) {}
+  RangeSelector Selector;
+};
+
+// A stencil operation to build a member access `e.m` or `e->m`, as appropriate.
+struct AccessData {
+  AccessData(StringRef BaseId, StencilPart Member)
+      : BaseId(BaseId), Member(std::move(Member)) {}
+  std::string BaseId;
+  StencilPart Member;
+};
+
+struct IfBoundData {
+  IfBoundData(StringRef Id, StencilPart TruePart, StencilPart FalsePart)
+      : Id(Id), TruePart(std::move(TruePart)), FalsePart(std::move(FalsePart)) {
+  }
+  std::string Id;
+  StencilPart TruePart;
+  StencilPart FalsePart;
+};
+
+std::string toStringData(const RawTextData &Data) {
+  std::string Result;
+  llvm::raw_string_ostream OS(Result);
+  OS << "\"";
+  OS.write_escaped(Data.Text);
+  OS << "\"";
+  OS.flush();
+  return Result;
+}
+
+std::string toStringData(const DebugPrintNodeData &Data) {
+  return (llvm::Twine("dPrint(\"") + Data.Id + "\")").str();
+}
+
+std::string toStringData(const UnaryOperationData &Data) {
+  StringRef OpName;
+  switch (Data.Op) {
+  case UnaryNodeOperator::Parens:
+    OpName = "expression";
+    break;
+  case UnaryNodeOperator::Deref:
+    OpName = "deref";
+    break;
+  case UnaryNodeOperator::Address:
+    OpName = "addressOf";
+    break;
+  }
+  return (OpName + "(\"" + Data.Id + "\")").str();
+}
+
+std::string toStringData(const SelectorData &) { return "selection(...)"; }
+
+std::string toStringData(const AccessData &Data) {
+  return (llvm::Twine("access(\"") + Data.BaseId + "\", " +
+          Data.Member.toString() + ")")
+      .str();
+}
+
+std::string toStringData(const IfBoundData &Data) {
+  return (llvm::Twine("ifBound(\"") + Data.Id + "\", " +
+          Data.TruePart.toString() + ", " + Data.FalsePart.toString() + ")")
+      .str();
+}
+
+std::string toStringData(const MatchConsumer<std::string> &) {
+  return "run(...)";
+}
+
+// The `evalData()` overloads evaluate the given stencil data to a string, given
+// the match result, and append it to `Result`. We define an overload for each
+// type of stencil data.
+
+Error evalData(const RawTextData &Data, const MatchFinder::MatchResult &,
+               std::string *Result) {
+  Result->append(Data.Text);
+  return Error::success();
+}
+
+Error evalData(const DebugPrintNodeData &Data,
+               const MatchFinder::MatchResult &Match, std::string *Result) {
+  std::string Output;
+  llvm::raw_string_ostream Os(Output);
+  auto NodeOrErr = getNode(Match.Nodes, Data.Id);
+  if (auto Err = NodeOrErr.takeError())
+    return Err;
+  NodeOrErr->print(Os, PrintingPolicy(Match.Context->getLangOpts()));
+  *Result += Os.str();
+  return Error::success();
+}
+
+Error evalData(const UnaryOperationData &Data,
+               const MatchFinder::MatchResult &Match, std::string *Result) {
+  const auto *E = Match.Nodes.getNodeAs<Expr>(Data.Id);
+  if (E == nullptr)
+    return llvm::make_error<StringError>(
+        errc::invalid_argument, "Id not bound or not Expr: " + Data.Id);
+  llvm::Optional<std::string> Source;
+  switch (Data.Op) {
+  case UnaryNodeOperator::Parens:
+    Source = tooling::buildParens(*E, *Match.Context);
+    break;
+  case UnaryNodeOperator::Deref:
+    Source = tooling::buildDereference(*E, *Match.Context);
+    break;
+  case UnaryNodeOperator::Address:
+    Source = tooling::buildAddressOf(*E, *Match.Context);
+    break;
+  }
+  if (!Source)
+    return llvm::make_error<StringError>(
+        errc::invalid_argument,
+        "Could not construct expression source from ID: " + Data.Id);
+  *Result += *Source;
+  return Error::success();
+}
+
+Error evalData(const SelectorData &Data, const MatchFinder::MatchResult &Match,
+               std::string *Result) {
+  auto Range = Data.Selector(Match);
+  if (!Range)
+    return Range.takeError();
+  *Result += tooling::getText(*Range, *Match.Context);
+  return Error::success();
+}
+
+Error evalData(const AccessData &Data, const MatchFinder::MatchResult &Match,
+               std::string *Result) {
+  const auto *E = Match.Nodes.getNodeAs<Expr>(Data.BaseId);
+  if (E == nullptr)
+    return llvm::make_error<StringError>(errc::invalid_argument,
+                                         "Id not bound: " + Data.BaseId);
+  if (!E->isImplicitCXXThis()) {
+    if (llvm::Optional<std::string> S =
+            E->getType()->isAnyPointerType()
+                ? tooling::buildArrow(*E, *Match.Context)
+                : tooling::buildDot(*E, *Match.Context))
+      *Result += *S;
+    else
+      return llvm::make_error<StringError>(
+          errc::invalid_argument,
+          "Could not construct object text from ID: " + Data.BaseId);
+  }
+  return Data.Member.eval(Match, Result);
+}
+
+Error evalData(const IfBoundData &Data, const MatchFinder::MatchResult &Match,
+               std::string *Result) {
+  auto &M = Match.Nodes.getMap();
+  return (M.find(Data.Id) != M.end() ? Data.TruePart : Data.FalsePart)
+      .eval(Match, Result);
+}
+
+Error evalData(const MatchConsumer<std::string> &Fn,
+               const MatchFinder::MatchResult &Match, std::string *Result) {
+  Expected<std::string> Value = Fn(Match);
+  if (!Value)
+    return Value.takeError();
+  *Result += *Value;
+  return Error::success();
+}
+
+template <typename T>
+class StencilPartImpl : public StencilPartInterface {
+  T Data;
+
+public:
+  template <typename... Ps>
+  explicit StencilPartImpl(Ps &&... Args) : Data(std::forward<Ps>(Args)...) {}
+
+  Error eval(const MatchFinder::MatchResult &Match,
+             std::string *Result) const override {
+    return evalData(Data, Match, Result);
+  }
+
+  std::string toString() const override { return toStringData(Data); }
+};
+} // namespace
+
+StencilPart Stencil::wrap(StringRef Text) {
+  return transformer::text(Text);
+}
+
+StencilPart Stencil::wrap(RangeSelector Selector) {
+  return transformer::selection(std::move(Selector));
+}
+
+void Stencil::append(Stencil OtherStencil) {
+  for (auto &Part : OtherStencil.Parts)
+    Parts.push_back(std::move(Part));
+}
+
+llvm::Expected<std::string>
+Stencil::eval(const MatchFinder::MatchResult &Match) const {
+  std::string Result;
+  for (const auto &Part : Parts)
+    if (auto Err = Part.eval(Match, &Result))
+      return std::move(Err);
+  return Result;
+}
+
+StencilPart transformer::text(StringRef Text) {
+  return StencilPart(std::make_shared<StencilPartImpl<RawTextData>>(Text));
+}
+
+StencilPart transformer::selection(RangeSelector Selector) {
+  return StencilPart(
+      std::make_shared<StencilPartImpl<SelectorData>>(std::move(Selector)));
+}
+
+StencilPart transformer::dPrint(StringRef Id) {
+  return StencilPart(std::make_shared<StencilPartImpl<DebugPrintNodeData>>(Id));
+}
+
+StencilPart transformer::expression(llvm::StringRef Id) {
+  return StencilPart(std::make_shared<StencilPartImpl<UnaryOperationData>>(
+      UnaryNodeOperator::Parens, Id));
+}
+
+StencilPart transformer::deref(llvm::StringRef ExprId) {
+  return StencilPart(std::make_shared<StencilPartImpl<UnaryOperationData>>(
+      UnaryNodeOperator::Deref, ExprId));
+}
+
+StencilPart transformer::addressOf(llvm::StringRef ExprId) {
+  return StencilPart(std::make_shared<StencilPartImpl<UnaryOperationData>>(
+      UnaryNodeOperator::Address, ExprId));
+}
+
+StencilPart transformer::access(StringRef BaseId, StencilPart Member) {
+  return StencilPart(
+      std::make_shared<StencilPartImpl<AccessData>>(BaseId, std::move(Member)));
+}
+
+StencilPart transformer::ifBound(StringRef Id, StencilPart TruePart,
+                             StencilPart FalsePart) {
+  return StencilPart(std::make_shared<StencilPartImpl<IfBoundData>>(
+      Id, std::move(TruePart), std::move(FalsePart)));
+}
+
+StencilPart transformer::run(MatchConsumer<std::string> Fn) {
+  return StencilPart(
+      std::make_shared<StencilPartImpl<MatchConsumer<std::string>>>(
+          std::move(Fn)));
+}
diff --git a/lib/Tooling/Transformer/Transformer.cpp b/lib/Tooling/Transformer/Transformer.cpp
new file mode 100644
index 000000000000..71f0646f4c0e
--- /dev/null
+++ b/lib/Tooling/Transformer/Transformer.cpp
@@ -0,0 +1,72 @@
+//===--- Transformer.cpp - Transformer library implementation ---*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/Transformer/Transformer.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchersInternal.h"
+#include "clang/Basic/SourceLocation.h"
+#include "clang/Tooling/Refactoring/AtomicChange.h"
+#include "llvm/Support/Error.h"
+#include <utility>
+#include <vector>
+
+using namespace clang;
+using namespace tooling;
+
+using ast_matchers::MatchFinder;
+
+void Transformer::registerMatchers(MatchFinder *MatchFinder) {
+  for (auto &Matcher : transformer::detail::buildMatchers(Rule))
+    MatchFinder->addDynamicMatcher(Matcher, this);
+}
+
+void Transformer::run(const MatchFinder::MatchResult &Result) {
+  if (Result.Context->getDiagnostics().hasErrorOccurred())
+    return;
+
+  transformer::RewriteRule::Case Case =
+      transformer::detail::findSelectedCase(Result, Rule);
+  auto Transformations = transformer::detail::translateEdits(Result, Case.Edits);
+  if (!Transformations) {
+    Consumer(Transformations.takeError());
+    return;
+  }
+
+  if (Transformations->empty()) {
+    // No rewrite applied (but no error encountered either).
+    transformer::detail::getRuleMatchLoc(Result).print(
+        llvm::errs() << "note: skipping match at loc ", *Result.SourceManager);
+    llvm::errs() << "\n";
+    return;
+  }
+
+  // Record the results in the AtomicChange, anchored at the location of the
+  // first change.
+  AtomicChange AC(*Result.SourceManager,
+                  (*Transformations)[0].Range.getBegin());
+  for (const auto &T : *Transformations) {
+    if (auto Err = AC.replace(*Result.SourceManager, T.Range, T.Replacement)) {
+      Consumer(std::move(Err));
+      return;
+    }
+  }
+
+  for (const auto &I : Case.AddedIncludes) {
+    auto &Header = I.first;
+    switch (I.second) {
+    case transformer::IncludeFormat::Quoted:
+      AC.addHeader(Header);
+      break;
+    case transformer::IncludeFormat::Angled:
+      AC.addHeader((llvm::Twine("<") + Header + ">").str());
+      break;
+    }
+  }
+
+  Consumer(std::move(AC));
+}