13 files changed, 3830 insertions, 2 deletions

diff --git a/lib/ARCMigrate/ARCMT.cpp b/lib/ARCMigrate/ARCMT.cpp
new file mode 100644
index 0000000000..bb66da6a71
--- /dev/null
+++ b/lib/ARCMigrate/ARCMT.cpp
@@ -0,0 +1,484 @@
+//===--- ARCMT.cpp - Migration to ARC mode --------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Internals.h"
+#include "clang/Frontend/ASTUnit.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/Utils.h"
+#include "clang/AST/ASTConsumer.h"
+#include "clang/Rewrite/Rewriter.h"
+#include "clang/Sema/SemaDiagnostic.h"
+#include "clang/Basic/DiagnosticCategories.h"
+#include "clang/Lex/Preprocessor.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/ADT/Triple.h"
+
+using namespace clang;
+using namespace arcmt;
+using llvm::StringRef;
+
+bool CapturedDiagList::clearDiagnostic(llvm::ArrayRef<unsigned> IDs,
+                                       SourceRange range) {
+  if (range.isInvalid())
+    return false;
+
+  bool cleared = false;
+  ListTy::iterator I = List.begin();
+  while (I != List.end()) {
+    FullSourceLoc diagLoc = I->getLocation();
+    if ((IDs.empty() || // empty means clear all diagnostics in the range.
+         std::find(IDs.begin(), IDs.end(), I->getID()) != IDs.end()) &&
+        !diagLoc.isBeforeInTranslationUnitThan(range.getBegin()) &&
+        (diagLoc == range.getEnd() ||
+           diagLoc.isBeforeInTranslationUnitThan(range.getEnd()))) {
+      cleared = true;
+      ListTy::iterator eraseS = I++;
+      while (I != List.end() && I->getLevel() == Diagnostic::Note)
+        ++I;
+      // Clear the diagnostic and any notes following it.
+      List.erase(eraseS, I);
+      continue;
+    }
+
+    ++I;
+  }
+
+  return cleared;
+}
+
+bool CapturedDiagList::hasDiagnostic(llvm::ArrayRef<unsigned> IDs,
+                                     SourceRange range) {
+  if (range.isInvalid())
+    return false;
+
+  ListTy::iterator I = List.begin();
+  while (I != List.end()) {
+    FullSourceLoc diagLoc = I->getLocation();
+    if ((IDs.empty() || // empty means any diagnostic in the range.
+         std::find(IDs.begin(), IDs.end(), I->getID()) != IDs.end()) &&
+        !diagLoc.isBeforeInTranslationUnitThan(range.getBegin()) &&
+        (diagLoc == range.getEnd() ||
+           diagLoc.isBeforeInTranslationUnitThan(range.getEnd()))) {
+      return true;
+    }
+
+    ++I;
+  }
+
+  return false;
+}
+
+void CapturedDiagList::reportDiagnostics(Diagnostic &Diags) {
+  for (ListTy::iterator I = List.begin(), E = List.end(); I != E; ++I)
+    Diags.Report(*I);
+}
+
+namespace {
+
+class CaptureDiagnosticClient : public DiagnosticClient {
+  Diagnostic &Diags;
+  CapturedDiagList &CapturedDiags;
+public:
+  CaptureDiagnosticClient(Diagnostic &diags,
+                          CapturedDiagList &capturedDiags)
+    : Diags(diags), CapturedDiags(capturedDiags) { }
+
+  virtual void HandleDiagnostic(Diagnostic::Level level,
+                                const DiagnosticInfo &Info) {
+    if (arcmt::isARCDiagnostic(Info.getID(), Diags) ||
+        level >= Diagnostic::Error || level == Diagnostic::Note) {
+      CapturedDiags.push_back(StoredDiagnostic(level, Info));
+      return;
+    }
+
+    // Non-ARC warnings are ignored.
+    Diags.setLastDiagnosticIgnored();
+  }
+};
+
+} // end anonymous namespace
+
+CompilerInvocation *createInvocationForMigration(CompilerInvocation &origCI) {
+  llvm::OwningPtr<CompilerInvocation> CInvok;
+  CInvok.reset(new CompilerInvocation(origCI));
+  CInvok->getPreprocessorOpts().ImplicitPCHInclude = std::string();
+  CInvok->getPreprocessorOpts().ImplicitPTHInclude = std::string();
+  std::string define = getARCMTMacroName();
+  define += '=';
+  CInvok->getPreprocessorOpts().addMacroDef(define);
+  CInvok->getLangOpts().ObjCAutoRefCount = true;
+  CInvok->getDiagnosticOpts().ErrorLimit = 0;
+  
+  // FIXME: Hackety hack! Try to find out if there is an ARC runtime.
+  bool hasARCRuntime = false;
+  llvm::SmallVector<std::string, 16> args;
+  args.push_back("-x");
+  args.push_back("objective-c");
+  args.push_back("-fobjc-arc");
+
+  llvm::Triple triple(CInvok->getTargetOpts().Triple);
+  if (triple.getOS() == llvm::Triple::IOS ||
+      triple.getOS() == llvm::Triple::MacOSX) {
+    unsigned Major, Minor, Micro;
+    triple.getOSVersion(Major, Minor, Micro);
+    llvm::SmallString<100> flag;
+    if (triple.getOS() == llvm::Triple::IOS)
+      flag += "-miphoneos-version-min=";
+    else
+      flag += "-mmacosx-version-min=";
+    llvm::raw_svector_ostream(flag) << Major << '.' << Minor << '.' << Micro;
+    args.push_back(flag.str());
+  }
+
+  args.push_back(origCI.getFrontendOpts().Inputs[0].second.c_str());
+  // Also push all defines to deal with the iOS simulator hack.
+  for (unsigned i = 0, e = origCI.getPreprocessorOpts().Macros.size();
+         i != e; ++i) {
+    std::string &def = origCI.getPreprocessorOpts().Macros[i].first;
+    bool isUndef = origCI.getPreprocessorOpts().Macros[i].second;
+    if (!isUndef) {
+      std::string newdef = "-D";
+      newdef += def;
+      args.push_back(newdef);
+    }
+  }
+
+  llvm::SmallVector<const char *, 16> cargs;
+  for (unsigned i = 0, e = args.size(); i != e; ++i)
+    cargs.push_back(args[i].c_str());
+
+  llvm::OwningPtr<CompilerInvocation> checkCI;
+  checkCI.reset(clang::createInvocationFromCommandLine(cargs));
+  if (checkCI)
+    hasARCRuntime = !checkCI->getLangOpts().ObjCNoAutoRefCountRuntime;
+
+  CInvok->getLangOpts().ObjCNoAutoRefCountRuntime = !hasARCRuntime;
+
+  return CInvok.take();
+}
+
+//===----------------------------------------------------------------------===//
+// checkForManualIssues.
+//===----------------------------------------------------------------------===//
+
+bool arcmt::checkForManualIssues(CompilerInvocation &origCI,
+                                 llvm::StringRef Filename, InputKind Kind,
+                                 DiagnosticClient *DiagClient) {
+  if (!origCI.getLangOpts().ObjC1)
+    return false;
+
+  std::vector<TransformFn> transforms = arcmt::getAllTransformations();
+  assert(!transforms.empty());
+
+  llvm::OwningPtr<CompilerInvocation> CInvok;
+  CInvok.reset(createInvocationForMigration(origCI));
+  CInvok->getFrontendOpts().Inputs.clear();
+  CInvok->getFrontendOpts().Inputs.push_back(std::make_pair(Kind, Filename));
+
+  CapturedDiagList capturedDiags;
+
+  assert(DiagClient);
+  llvm::IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
+  llvm::IntrusiveRefCntPtr<Diagnostic> Diags(
+                 new Diagnostic(DiagID, DiagClient, /*ShouldOwnClient=*/false));
+
+  // Filter of all diagnostics.
+  CaptureDiagnosticClient errRec(*Diags, capturedDiags);
+  Diags->setClient(&errRec, /*ShouldOwnClient=*/false);
+
+  llvm::OwningPtr<ASTUnit> Unit(
+      ASTUnit::LoadFromCompilerInvocationAction(CInvok.take(), Diags));
+  if (!Unit)
+    return true;
+
+  // Don't filter diagnostics anymore.
+  Diags->setClient(DiagClient, /*ShouldOwnClient=*/false);
+
+  ASTContext &Ctx = Unit->getASTContext();
+
+  if (Diags->hasFatalErrorOccurred()) {
+    Diags->Reset();
+    DiagClient->BeginSourceFile(Ctx.getLangOptions(), &Unit->getPreprocessor());
+    capturedDiags.reportDiagnostics(*Diags);
+    DiagClient->EndSourceFile();
+    return true;
+  }
+
+  // After parsing of source files ended, we want to reuse the
+  // diagnostics objects to emit further diagnostics.
+  // We call BeginSourceFile because DiagnosticClient requires that 
+  // diagnostics with source range information are emitted only in between
+  // BeginSourceFile() and EndSourceFile().
+  DiagClient->BeginSourceFile(Ctx.getLangOptions(), &Unit->getPreprocessor());
+
+  // No macros will be added since we are just checking and we won't modify
+  // source code.
+  std::vector<SourceLocation> ARCMTMacroLocs;
+
+  TransformActions testAct(*Diags, capturedDiags, Ctx, Unit->getPreprocessor());
+  MigrationPass pass(Ctx, Unit->getSema(), testAct, ARCMTMacroLocs);
+
+  for (unsigned i=0, e = transforms.size(); i != e; ++i)
+    transforms[i](pass);
+
+  capturedDiags.reportDiagnostics(*Diags);
+
+  DiagClient->EndSourceFile();
+
+  return Diags->getClient()->getNumErrors() > 0;
+}
+
+//===----------------------------------------------------------------------===//
+// applyTransformations.
+//===----------------------------------------------------------------------===//
+
+bool arcmt::applyTransformations(CompilerInvocation &origCI,
+                                 llvm::StringRef Filename, InputKind Kind,
+                                 DiagnosticClient *DiagClient) {
+  if (!origCI.getLangOpts().ObjC1)
+    return false;
+
+  // Make sure checking is successful first.
+  CompilerInvocation CInvokForCheck(origCI);
+  if (arcmt::checkForManualIssues(CInvokForCheck, Filename, Kind, DiagClient))
+    return true;
+
+  CompilerInvocation CInvok(origCI);
+  CInvok.getFrontendOpts().Inputs.clear();
+  CInvok.getFrontendOpts().Inputs.push_back(std::make_pair(Kind, Filename));
+  
+  MigrationProcess migration(CInvok, DiagClient);
+
+  std::vector<TransformFn> transforms = arcmt::getAllTransformations();
+  assert(!transforms.empty());
+
+  for (unsigned i=0, e = transforms.size(); i != e; ++i) {
+    bool err = migration.applyTransform(transforms[i]);
+    if (err) return true;
+  }
+
+  origCI.getLangOpts().ObjCAutoRefCount = true;
+
+  llvm::IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
+  llvm::IntrusiveRefCntPtr<Diagnostic> Diags(
+                 new Diagnostic(DiagID, DiagClient, /*ShouldOwnClient=*/false));
+  return migration.getRemapper().overwriteOriginal(*Diags);
+}
+
+//===----------------------------------------------------------------------===//
+// applyTransformationsInMemory.
+//===----------------------------------------------------------------------===//
+
+bool arcmt::applyTransformationsInMemory(CompilerInvocation &origCI,
+                                       llvm::StringRef Filename, InputKind Kind,
+                                       DiagnosticClient *DiagClient) {
+  if (!origCI.getLangOpts().ObjC1)
+    return false;
+
+  // Make sure checking is successful first.
+  CompilerInvocation CInvokForCheck(origCI);
+  if (arcmt::checkForManualIssues(CInvokForCheck, Filename, Kind, DiagClient))
+    return true;
+
+  CompilerInvocation CInvok(origCI);
+  CInvok.getFrontendOpts().Inputs.clear();
+  CInvok.getFrontendOpts().Inputs.push_back(std::make_pair(Kind, Filename));
+  
+  MigrationProcess migration(CInvok, DiagClient);
+
+  std::vector<TransformFn> transforms = arcmt::getAllTransformations();
+  assert(!transforms.empty());
+
+  for (unsigned i=0, e = transforms.size(); i != e; ++i) {
+    bool err = migration.applyTransform(transforms[i]);
+    if (err) return true;
+  }
+
+  origCI.getLangOpts().ObjCAutoRefCount = true;
+  migration.getRemapper().transferMappingsAndClear(origCI);
+
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// CollectTransformActions.
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+class ARCMTMacroTrackerPPCallbacks : public PPCallbacks {
+  std::vector<SourceLocation> &ARCMTMacroLocs;
+
+public:
+  ARCMTMacroTrackerPPCallbacks(std::vector<SourceLocation> &ARCMTMacroLocs)
+    : ARCMTMacroLocs(ARCMTMacroLocs) { }
+
+  virtual void MacroExpands(const Token &MacroNameTok, const MacroInfo *MI) {
+    if (MacroNameTok.getIdentifierInfo()->getName() == getARCMTMacroName())
+      ARCMTMacroLocs.push_back(MacroNameTok.getLocation());
+  }
+};
+
+class ARCMTMacroTrackerAction : public ASTFrontendAction {
+  std::vector<SourceLocation> &ARCMTMacroLocs;
+
+public:
+  ARCMTMacroTrackerAction(std::vector<SourceLocation> &ARCMTMacroLocs)
+    : ARCMTMacroLocs(ARCMTMacroLocs) { }
+
+  virtual ASTConsumer *CreateASTConsumer(CompilerInstance &CI,
+                                         llvm::StringRef InFile) {
+    CI.getPreprocessor().addPPCallbacks(
+                              new ARCMTMacroTrackerPPCallbacks(ARCMTMacroLocs));
+    return new ASTConsumer();
+  }
+};
+
+class RewritesApplicator : public TransformActions::RewriteReceiver {
+  Rewriter &rewriter;
+  ASTContext &Ctx;
+  MigrationProcess::RewriteListener *Listener;
+
+public:
+  RewritesApplicator(Rewriter &rewriter, ASTContext &ctx,
+                     MigrationProcess::RewriteListener *listener)
+    : rewriter(rewriter), Ctx(ctx), Listener(listener) {
+    if (Listener)
+      Listener->start(ctx);
+  }
+  ~RewritesApplicator() {
+    if (Listener)
+      Listener->finish();
+  }
+
+  virtual void insert(SourceLocation loc, llvm::StringRef text) {
+    bool err = rewriter.InsertText(loc, text, /*InsertAfter=*/true,
+                                   /*indentNewLines=*/true);
+    if (!err && Listener)
+      Listener->insert(loc, text);
+  }
+
+  virtual void remove(CharSourceRange range) {
+    Rewriter::RewriteOptions removeOpts;
+    removeOpts.IncludeInsertsAtBeginOfRange = false;
+    removeOpts.IncludeInsertsAtEndOfRange = false;
+    removeOpts.RemoveLineIfEmpty = true;
+
+    bool err = rewriter.RemoveText(range, removeOpts);
+    if (!err && Listener)
+      Listener->remove(range);
+  }
+
+  virtual void increaseIndentation(CharSourceRange range,
+                                    SourceLocation parentIndent) {
+    rewriter.IncreaseIndentation(range, parentIndent);
+  }
+};
+
+} // end anonymous namespace.
+
+/// \brief Anchor for VTable.
+MigrationProcess::RewriteListener::~RewriteListener() { }
+
+bool MigrationProcess::applyTransform(TransformFn trans,
+                                      RewriteListener *listener) {
+  llvm::OwningPtr<CompilerInvocation> CInvok;
+  CInvok.reset(createInvocationForMigration(OrigCI));
+  CInvok->getDiagnosticOpts().IgnoreWarnings = true;
+
+  Remapper.applyMappings(*CInvok);
+
+  CapturedDiagList capturedDiags;
+  std::vector<SourceLocation> ARCMTMacroLocs;
+
+  assert(DiagClient);
+  llvm::IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
+  llvm::IntrusiveRefCntPtr<Diagnostic> Diags(
+               new Diagnostic(DiagID, DiagClient, /*ShouldOwnClient=*/false));
+
+  // Filter of all diagnostics.
+  CaptureDiagnosticClient errRec(*Diags, capturedDiags);
+  Diags->setClient(&errRec, /*ShouldOwnClient=*/false);
+
+  llvm::OwningPtr<ARCMTMacroTrackerAction> ASTAction;
+  ASTAction.reset(new ARCMTMacroTrackerAction(ARCMTMacroLocs));
+
+  llvm::OwningPtr<ASTUnit> Unit(
+      ASTUnit::LoadFromCompilerInvocationAction(CInvok.take(), Diags,
+                                                ASTAction.get()));
+  if (!Unit)
+    return true;
+  Unit->setOwnsRemappedFileBuffers(false); // FileRemapper manages that.
+
+  // Don't filter diagnostics anymore.
+  Diags->setClient(DiagClient, /*ShouldOwnClient=*/false);
+
+  ASTContext &Ctx = Unit->getASTContext();
+
+  if (Diags->hasFatalErrorOccurred()) {
+    Diags->Reset();
+    DiagClient->BeginSourceFile(Ctx.getLangOptions(), &Unit->getPreprocessor());
+    capturedDiags.reportDiagnostics(*Diags);
+    DiagClient->EndSourceFile();
+    return true;
+  }
+
+  // After parsing of source files ended, we want to reuse the
+  // diagnostics objects to emit further diagnostics.
+  // We call BeginSourceFile because DiagnosticClient requires that 
+  // diagnostics with source range information are emitted only in between
+  // BeginSourceFile() and EndSourceFile().
+  DiagClient->BeginSourceFile(Ctx.getLangOptions(), &Unit->getPreprocessor());
+
+  Rewriter rewriter(Ctx.getSourceManager(), Ctx.getLangOptions());
+  TransformActions TA(*Diags, capturedDiags, Ctx, Unit->getPreprocessor());
+  MigrationPass pass(Ctx, Unit->getSema(), TA, ARCMTMacroLocs);
+
+  trans(pass);
+
+  {
+    RewritesApplicator applicator(rewriter, Ctx, listener);
+    TA.applyRewrites(applicator);
+  }
+
+  DiagClient->EndSourceFile();
+
+  if (DiagClient->getNumErrors())
+    return true;
+
+  for (Rewriter::buffer_iterator
+        I = rewriter.buffer_begin(), E = rewriter.buffer_end(); I != E; ++I) {
+    FileID FID = I->first;
+    RewriteBuffer &buf = I->second;
+    const FileEntry *file = Ctx.getSourceManager().getFileEntryForID(FID);
+    assert(file);
+    std::string newFname = file->getName();
+    newFname += "-trans";
+    llvm::SmallString<512> newText;
+    llvm::raw_svector_ostream vecOS(newText);
+    buf.write(vecOS);
+    vecOS.flush();
+    llvm::MemoryBuffer *memBuf = llvm::MemoryBuffer::getMemBufferCopy(
+                   llvm::StringRef(newText.data(), newText.size()), newFname);
+    llvm::SmallString<64> filePath(file->getName());
+    Unit->getFileManager().FixupRelativePath(filePath);
+    Remapper.remap(filePath.str(), memBuf);
+  }
+
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// isARCDiagnostic.
+//===----------------------------------------------------------------------===//
+
+bool arcmt::isARCDiagnostic(unsigned diagID, Diagnostic &Diag) {
+  return Diag.getDiagnosticIDs()->getCategoryNumberForDiag(diagID) ==
+           diag::DiagCat_Automatic_Reference_Counting_Issue;
+}
diff --git a/lib/ARCMigrate/CMakeLists.txt b/lib/ARCMigrate/CMakeLists.txt
new file mode 100644
index 0000000000..3645a22356
--- /dev/null
+++ b/lib/ARCMigrate/CMakeLists.txt
@@ -0,0 +1,14 @@
+set(LLVM_USED_LIBS clangBasic clangAST clangParse clangFrontend clangRewrite)
+
+add_clang_library(clangARCMigrate
+  ARCMT.cpp
+  FileRemapper.cpp
+  TransformActions.cpp
+  Transforms.cpp
+  )
+
+add_dependencies(clangARCMigrate
+  ClangAttrClasses
+  ClangAttrList
+  ClangDeclNodes
+  ClangStmtNodes)
diff --git a/lib/ARCMigrate/FileRemapper.cpp b/lib/ARCMigrate/FileRemapper.cpp
new file mode 100644
index 0000000000..ae5d3a3c93
--- /dev/null
+++ b/lib/ARCMigrate/FileRemapper.cpp
@@ -0,0 +1,290 @@
+//===--- FileRemapper.cpp - File Remapping Helper -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/ARCMigrate/FileRemapper.h"
+#include "clang/Frontend/CompilerInvocation.h"
+#include "clang/Basic/FileManager.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/raw_ostream.h"
+#include <fstream>
+
+using namespace clang;
+using namespace arcmt;
+
+FileRemapper::FileRemapper() {
+  FileMgr.reset(new FileManager(FileSystemOptions()));
+}
+
+FileRemapper::~FileRemapper() {
+  clear();
+}
+
+void FileRemapper::clear(llvm::StringRef outputDir) {
+  for (MappingsTy::iterator
+         I = FromToMappings.begin(), E = FromToMappings.end(); I != E; ++I)
+    resetTarget(I->second);
+  FromToMappings.clear();
+  assert(ToFromMappings.empty());
+  if (!outputDir.empty()) {
+    std::string infoFile = getRemapInfoFile(outputDir);
+    bool existed;
+    llvm::sys::fs::remove(infoFile, existed);
+  }
+}
+
+std::string FileRemapper::getRemapInfoFile(llvm::StringRef outputDir) {
+  assert(!outputDir.empty());
+  llvm::sys::Path dir(outputDir);
+  llvm::sys::Path infoFile = dir;
+  infoFile.appendComponent("remap");
+  return infoFile.str();
+}
+
+bool FileRemapper::initFromDisk(llvm::StringRef outputDir, Diagnostic &Diag,
+                                bool ignoreIfFilesChanged) {
+  assert(FromToMappings.empty() &&
+         "initFromDisk should be called before any remap calls");
+  std::string infoFile = getRemapInfoFile(outputDir);
+  bool fileExists = false;
+  llvm::sys::fs::exists(infoFile, fileExists);
+  if (!fileExists)
+    return false;
+
+  std::vector<std::pair<const FileEntry *, const FileEntry *> > pairs;
+
+  std::ifstream fin(infoFile.c_str());
+  if (!fin.good())
+    return report(std::string("Error opening file: ") + infoFile, Diag);
+
+  while (true) {
+    std::string fromFilename, toFilename;
+    uint64_t timeModified;
+
+    fin >> fromFilename >> timeModified >> toFilename;
+    if (fin.eof())
+      break;
+    if (!fin.good()) {
+      if (ignoreIfFilesChanged)
+        return false;
+      return report(std::string("Error in format of file: ") + infoFile, Diag);
+    }
+
+    const FileEntry *origFE = FileMgr->getFile(fromFilename);
+    if (!origFE) {
+      if (ignoreIfFilesChanged)
+        continue;
+      return report(std::string("File does not exist: ") + fromFilename, Diag);
+    }
+    const FileEntry *newFE = FileMgr->getFile(toFilename);
+    if (!newFE) {
+      if (ignoreIfFilesChanged)
+        continue;
+      return report(std::string("File does not exist: ") + toFilename, Diag);
+    }
+
+    if ((uint64_t)origFE->getModificationTime() != timeModified) {
+      if (ignoreIfFilesChanged)
+        continue;
+      return report(std::string("File was modified: ") + fromFilename, Diag);
+    }
+
+    pairs.push_back(std::make_pair(origFE, newFE));
+  }
+
+  for (unsigned i = 0, e = pairs.size(); i != e; ++i)
+    remap(pairs[i].first, pairs[i].second);
+
+  return false;
+}
+
+bool FileRemapper::flushToDisk(llvm::StringRef outputDir, Diagnostic &Diag) {
+  using namespace llvm::sys;
+
+  bool existed;
+  if (fs::create_directory(outputDir, existed) != llvm::errc::success)
+    return report(std::string("Could not create directory: ") + outputDir.str(),
+                  Diag);
+
+  std::string errMsg;
+  std::string infoFile = getRemapInfoFile(outputDir);
+  llvm::raw_fd_ostream infoOut(infoFile.c_str(), errMsg,
+                               llvm::raw_fd_ostream::F_Binary);
+  if (!errMsg.empty() || infoOut.has_error())
+    return report(errMsg, Diag);
+
+  for (MappingsTy::iterator
+         I = FromToMappings.begin(), E = FromToMappings.end(); I != E; ++I) {
+
+    const FileEntry *origFE = I->first;
+    infoOut << origFE->getName() << '\n';
+    infoOut << (uint64_t)origFE->getModificationTime() << '\n';
+
+    if (const FileEntry *FE = I->second.dyn_cast<const FileEntry *>()) {
+      infoOut << FE->getName() << '\n';
+    } else {
+
+      llvm::SmallString<64> tempPath;
+      tempPath = path::filename(origFE->getName());
+      tempPath += "-%%%%%%%%";
+      tempPath += path::extension(origFE->getName());
+      int fd;
+      if (fs::unique_file(tempPath.str(), fd, tempPath) != llvm::errc::success)
+        return report(std::string("Could not create file: ") + tempPath.c_str(),
+                      Diag);
+
+      llvm::raw_fd_ostream newOut(fd, /*shouldClose=*/true);
+      llvm::MemoryBuffer *mem = I->second.get<llvm::MemoryBuffer *>();
+      newOut.write(mem->getBufferStart(), mem->getBufferSize());
+      newOut.close();
+      
+      const FileEntry *newE = FileMgr->getFile(tempPath);
+      remap(origFE, newE);
+      infoOut << newE->getName() << '\n';
+    }
+  }
+
+  infoOut.close();
+  return false;
+}
+
+bool FileRemapper::overwriteOriginal(Diagnostic &Diag,
+                                     llvm::StringRef outputDir) {
+  using namespace llvm::sys;
+
+  for (MappingsTy::iterator
+         I = FromToMappings.begin(), E = FromToMappings.end(); I != E; ++I) {
+    const FileEntry *origFE = I->first;
+    if (const FileEntry *newFE = I->second.dyn_cast<const FileEntry *>()) {
+      if (fs::copy_file(newFE->getName(), origFE->getName(),
+                 fs::copy_option::overwrite_if_exists) != llvm::errc::success) {
+        std::string err = "Could not copy file '";
+        llvm::raw_string_ostream os(err);
+        os << "Could not copy file '" << newFE->getName() << "' to file '"
+           << origFE->getName() << "'";
+        os.flush();
+        return report(err, Diag);
+      }
+    } else {
+
+      bool fileExists = false;
+      fs::exists(origFE->getName(), fileExists);
+      if (!fileExists)
+        return report(std::string("File does not exist: ") + origFE->getName(),
+                      Diag);
+
+      std::string errMsg;
+      llvm::raw_fd_ostream Out(origFE->getName(), errMsg,
+                               llvm::raw_fd_ostream::F_Binary);
+      if (!errMsg.empty() || Out.has_error())
+        return report(errMsg, Diag);
+
+      llvm::MemoryBuffer *mem = I->second.get<llvm::MemoryBuffer *>();
+      Out.write(mem->getBufferStart(), mem->getBufferSize());
+      Out.close();
+    }
+  }
+
+  clear(outputDir);
+  return false;
+}
+
+void FileRemapper::applyMappings(CompilerInvocation &CI) const {
+  PreprocessorOptions &PPOpts = CI.getPreprocessorOpts();
+  for (MappingsTy::const_iterator
+         I = FromToMappings.begin(), E = FromToMappings.end(); I != E; ++I) {
+    if (const FileEntry *FE = I->second.dyn_cast<const FileEntry *>()) {
+      PPOpts.addRemappedFile(I->first->getName(), FE->getName());
+    } else {
+      llvm::MemoryBuffer *mem = I->second.get<llvm::MemoryBuffer *>();
+      PPOpts.addRemappedFile(I->first->getName(), mem);
+    }
+  }
+
+  PPOpts.RetainRemappedFileBuffers = true;
+}
+
+void FileRemapper::transferMappingsAndClear(CompilerInvocation &CI) {
+  PreprocessorOptions &PPOpts = CI.getPreprocessorOpts();
+  for (MappingsTy::iterator
+         I = FromToMappings.begin(), E = FromToMappings.end(); I != E; ++I) {
+    if (const FileEntry *FE = I->second.dyn_cast<const FileEntry *>()) {
+      PPOpts.addRemappedFile(I->first->getName(), FE->getName());
+    } else {
+      llvm::MemoryBuffer *mem = I->second.get<llvm::MemoryBuffer *>();
+      PPOpts.addRemappedFile(I->first->getName(), mem);
+    }
+    I->second = Target();
+  }
+
+  PPOpts.RetainRemappedFileBuffers = false;
+  clear();
+}
+
+void FileRemapper::remap(llvm::StringRef filePath, llvm::MemoryBuffer *memBuf) {
+  remap(getOriginalFile(filePath), memBuf);
+}
+
+void FileRemapper::remap(llvm::StringRef filePath, llvm::StringRef newPath) {
+  const FileEntry *file = getOriginalFile(filePath);
+  const FileEntry *newfile = FileMgr->getFile(newPath);
+  remap(file, newfile);
+}
+
+void FileRemapper::remap(const FileEntry *file, llvm::MemoryBuffer *memBuf) {
+  assert(file);
+  Target &targ = FromToMappings[file];
+  resetTarget(targ);
+  targ = memBuf;
+}
+
+void FileRemapper::remap(const FileEntry *file, const FileEntry *newfile) {
+  assert(file && newfile);
+  Target &targ = FromToMappings[file];
+  resetTarget(targ);
+  targ = newfile;
+  ToFromMappings[newfile] = file;
+}
+
+const FileEntry *FileRemapper::getOriginalFile(llvm::StringRef filePath) {
+  const FileEntry *file = FileMgr->getFile(filePath);
+  // If we are updating a file that overriden an original file,
+  // actually update the original file.
+  llvm::DenseMap<const FileEntry *, const FileEntry *>::iterator
+    I = ToFromMappings.find(file);
+  if (I != ToFromMappings.end()) {
+    file = I->second;
+    assert(FromToMappings.find(file) != FromToMappings.end() &&
+           "Original file not in mappings!");
+  }
+  return file;
+}
+
+void FileRemapper::resetTarget(Target &targ) {
+  if (!targ)
+    return;
+
+  if (llvm::MemoryBuffer *oldmem = targ.dyn_cast<llvm::MemoryBuffer *>()) {
+    delete oldmem;
+  } else {
+    const FileEntry *toFE = targ.get<const FileEntry *>();
+    llvm::DenseMap<const FileEntry *, const FileEntry *>::iterator
+      I = ToFromMappings.find(toFE);
+    if (I != ToFromMappings.end())
+      ToFromMappings.erase(I);
+  }
+}
+
+bool FileRemapper::report(const std::string &err, Diagnostic &Diag) {
+  unsigned ID = Diag.getDiagnosticIDs()->getCustomDiagID(DiagnosticIDs::Error,
+                                                         err);
+  Diag.Report(ID);
+  return true;
+}
diff --git a/lib/ARCMigrate/Internals.h b/lib/ARCMigrate/Internals.h
new file mode 100644
index 0000000000..fdc0aad176
--- /dev/null
+++ b/lib/ARCMigrate/Internals.h
@@ -0,0 +1,146 @@
+//===-- Internals.h - Implementation Details---------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_ARCMIGRATE_INTERNALS_H
+#define LLVM_CLANG_LIB_ARCMIGRATE_INTERNALS_H
+
+#include "clang/ARCMigrate/ARCMT.h"
+#include "llvm/ADT/ArrayRef.h"
+
+namespace clang {
+  class Sema;
+  class Stmt;
+
+namespace arcmt {
+
+class CapturedDiagList {
+  typedef std::list<StoredDiagnostic> ListTy;
+  ListTy List;
+  
+public:
+  void push_back(const StoredDiagnostic &diag) { List.push_back(diag); }
+
+  bool clearDiagnostic(llvm::ArrayRef<unsigned> IDs, SourceRange range);
+  bool hasDiagnostic(llvm::ArrayRef<unsigned> IDs, SourceRange range);
+
+  void reportDiagnostics(Diagnostic &diags);
+};
+
+class TransformActions {
+  Diagnostic &Diags;
+  CapturedDiagList &CapturedDiags;
+  void *Impl; // TransformActionsImpl.
+
+public:
+  TransformActions(Diagnostic &diag, CapturedDiagList &capturedDiags,
+                   ASTContext &ctx, Preprocessor &PP);
+  ~TransformActions();
+
+  void startTransaction();
+  bool commitTransaction();
+  void abortTransaction();
+
+  void insert(SourceLocation loc, llvm::StringRef text);
+  void insertAfterToken(SourceLocation loc, llvm::StringRef text);
+  void remove(SourceRange range);
+  void removeStmt(Stmt *S);
+  void replace(SourceRange range, llvm::StringRef text);
+  void replace(SourceRange range, SourceRange replacementRange);
+  void replaceStmt(Stmt *S, llvm::StringRef text);
+  void replaceText(SourceLocation loc, llvm::StringRef text,
+                   llvm::StringRef replacementText);
+  void increaseIndentation(SourceRange range,
+                           SourceLocation parentIndent);
+
+  bool clearDiagnostic(llvm::ArrayRef<unsigned> IDs, SourceRange range);
+  bool clearAllDiagnostics(SourceRange range) {
+    return clearDiagnostic(llvm::ArrayRef<unsigned>(), range);
+  }
+  bool clearDiagnostic(unsigned ID1, unsigned ID2, SourceRange range) {
+    unsigned IDs[] = { ID1, ID2 };
+    return clearDiagnostic(IDs, range);
+  }
+  bool clearDiagnostic(unsigned ID1, unsigned ID2, unsigned ID3,
+                       SourceRange range) {
+    unsigned IDs[] = { ID1, ID2, ID3 };
+    return clearDiagnostic(IDs, range);
+  }
+
+  bool hasDiagnostic(unsigned ID, SourceRange range) {
+    return CapturedDiags.hasDiagnostic(ID, range);
+  }
+
+  bool hasDiagnostic(unsigned ID1, unsigned ID2, SourceRange range) {
+    unsigned IDs[] = { ID1, ID2 };
+    return CapturedDiags.hasDiagnostic(IDs, range);
+  }
+
+  void reportError(llvm::StringRef error, SourceLocation loc,
+                   SourceRange range = SourceRange());
+  void reportNote(llvm::StringRef note, SourceLocation loc,
+                  SourceRange range = SourceRange());
+
+  class RewriteReceiver {
+  public:
+    virtual ~RewriteReceiver();
+
+    virtual void insert(SourceLocation loc, llvm::StringRef text) = 0;
+    virtual void remove(CharSourceRange range) = 0;
+    virtual void increaseIndentation(CharSourceRange range,
+                                     SourceLocation parentIndent) = 0;
+  };
+
+  void applyRewrites(RewriteReceiver &receiver);
+};
+
+class Transaction {
+  TransformActions &TA;
+  bool Aborted;
+
+public:
+  Transaction(TransformActions &TA) : TA(TA), Aborted(false) {
+    TA.startTransaction();
+  }
+
+  ~Transaction() {
+    if (!isAborted())
+      TA.commitTransaction();
+  }
+
+  void abort() {
+    TA.abortTransaction();
+    Aborted = true;
+  }
+
+  bool isAborted() const { return Aborted; }
+};
+
+class MigrationPass {
+public:
+  ASTContext &Ctx;
+  Sema &SemaRef;
+  TransformActions &TA;
+  std::vector<SourceLocation> &ARCMTMacroLocs;
+
+  MigrationPass(ASTContext &Ctx, Sema &sema, TransformActions &TA,
+                std::vector<SourceLocation> &ARCMTMacroLocs)
+    : Ctx(Ctx), SemaRef(sema), TA(TA), ARCMTMacroLocs(ARCMTMacroLocs) { }
+};
+
+bool isARCDiagnostic(unsigned diagID, Diagnostic &Diag);
+
+static inline llvm::StringRef getARCMTMacroName() {
+  return "__IMPL_ARCMT_REMOVED_EXPR__";
+}
+
+} // end namespace arcmt
+
+} // end namespace clang
+
+#endif
diff --git a/lib/ARCMigrate/Makefile b/lib/ARCMigrate/Makefile
new file mode 100644
index 0000000000..5232c5e5af
--- /dev/null
+++ b/lib/ARCMigrate/Makefile
@@ -0,0 +1,18 @@