Add the clang library to the repo (with some of my changes, too).

1 files changed, 666 insertions, 0 deletions

diff --git a/clang/lib/Lex/Preprocessor.cpp b/clang/lib/Lex/Preprocessor.cpp
new file mode 100644
index 0000000..06e5685
--- /dev/null
+++ b/clang/lib/Lex/Preprocessor.cpp
@@ -0,0 +1,666 @@
+//===--- Preprocess.cpp - C Language Family Preprocessor Implementation ---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the Preprocessor interface.
+//
+//===----------------------------------------------------------------------===//
+//
+// Options to support:
+//   -H       - Print the name of each header file used.
+//   -d[DNI] - Dump various things.
+//   -fworking-directory - #line's with preprocessor's working dir.
+//   -fpreprocessed
+//   -dependency-file,-M,-MM,-MF,-MG,-MP,-MT,-MQ,-MD,-MMD
+//   -W*
+//   -w
+//
+// Messages to emit:
+//   "Multiple include guards may be useful for:\n"
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Lex/Preprocessor.h"
+#include "MacroArgs.h"
+#include "clang/Lex/ExternalPreprocessorSource.h"
+#include "clang/Lex/HeaderSearch.h"
+#include "clang/Lex/MacroInfo.h"
+#include "clang/Lex/Pragma.h"
+#include "clang/Lex/PreprocessingRecord.h"
+#include "clang/Lex/ScratchBuffer.h"
+#include "clang/Lex/LexDiagnostic.h"
+#include "clang/Lex/CodeCompletionHandler.h"
+#include "clang/Lex/ModuleLoader.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/TargetInfo.h"
+#include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Capacity.h"
+using namespace clang;
+
+//===----------------------------------------------------------------------===//
+ExternalPreprocessorSource::~ExternalPreprocessorSource() { }
+
+Preprocessor::Preprocessor(DiagnosticsEngine &diags, LangOptions &opts,
+                           const TargetInfo *target, SourceManager &SM,
+                           HeaderSearch &Headers, ModuleLoader &TheModuleLoader,
+                           IdentifierInfoLookup* IILookup,
+                           bool OwnsHeaders,
+                           bool DelayInitialization,
+                           bool IncrProcessing)
+  : Diags(&diags), LangOpts(opts), Target(target),FileMgr(Headers.getFileMgr()),
+    SourceMgr(SM), HeaderInfo(Headers), TheModuleLoader(TheModuleLoader),
+    ExternalSource(0), Identifiers(opts, IILookup), 
+    IncrementalProcessing(IncrProcessing), CodeComplete(0), 
+    CodeCompletionFile(0), CodeCompletionOffset(0), CodeCompletionReached(0),
+    SkipMainFilePreamble(0, true), CurPPLexer(0), 
+    CurDirLookup(0), CurLexerKind(CLK_Lexer), Callbacks(0), MacroArgCache(0), 
+    Record(0), MIChainHead(0), MICache(0) 
+{
+  OwnsHeaderSearch = OwnsHeaders;
+
+  if (!DelayInitialization) {
+    assert(Target && "Must provide target information for PP initialization");
+    Initialize(*Target);
+  }
+}
+
+Preprocessor::~Preprocessor() {
+  assert(BacktrackPositions.empty() && "EnableBacktrack/Backtrack imbalance!");
+
+  while (!IncludeMacroStack.empty()) {
+    delete IncludeMacroStack.back().TheLexer;
+    delete IncludeMacroStack.back().TheTokenLexer;
+    IncludeMacroStack.pop_back();
+  }
+
+  // Free any macro definitions.
+  for (MacroInfoChain *I = MIChainHead ; I ; I = I->Next)
+    I->MI.Destroy();
+
+  // Free any cached macro expanders.
+  for (unsigned i = 0, e = NumCachedTokenLexers; i != e; ++i)
+    delete TokenLexerCache[i];
+
+  // Free any cached MacroArgs.
+  for (MacroArgs *ArgList = MacroArgCache; ArgList; )
+    ArgList = ArgList->deallocate();
+
+  // Release pragma information.
+  delete PragmaHandlers;
+
+  // Delete the scratch buffer info.
+  delete ScratchBuf;
+
+  // Delete the header search info, if we own it.
+  if (OwnsHeaderSearch)
+    delete &HeaderInfo;
+
+  delete Callbacks;
+}
+
+void Preprocessor::Initialize(const TargetInfo &Target) {
+  assert((!this->Target || this->Target == &Target) &&
+         "Invalid override of target information");
+  this->Target = &Target;
+  
+  // Initialize information about built-ins.
+  BuiltinInfo.InitializeTarget(Target);
+  
+  ScratchBuf = new ScratchBuffer(SourceMgr);
+  CounterValue = 0; // __COUNTER__ starts at 0.
+  
+  // Clear stats.
+  NumDirectives = NumDefined = NumUndefined = NumPragma = 0;
+  NumIf = NumElse = NumEndif = 0;
+  NumEnteredSourceFiles = 0;
+  NumMacroExpanded = NumFnMacroExpanded = NumBuiltinMacroExpanded = 0;
+  NumFastMacroExpanded = NumTokenPaste = NumFastTokenPaste = 0;
+  MaxIncludeStackDepth = 0;
+  NumSkipped = 0;
+  
+  // Default to discarding comments.
+  KeepComments = false;
+  KeepMacroComments = false;
+  SuppressIncludeNotFoundError = false;
+  
+  // Macro expansion is enabled.
+  DisableMacroExpansion = false;
+  InMacroArgs = false;
+  InMacroArgPreExpansion = false;
+  NumCachedTokenLexers = 0;
+  
+  CachedLexPos = 0;
+  
+  // We haven't read anything from the external source.
+  ReadMacrosFromExternalSource = false;
+  
+  // "Poison" __VA_ARGS__, which can only appear in the expansion of a macro.
+  // This gets unpoisoned where it is allowed.
+  (Ident__VA_ARGS__ = getIdentifierInfo("__VA_ARGS__"))->setIsPoisoned();
+  SetPoisonReason(Ident__VA_ARGS__,diag::ext_pp_bad_vaargs_use);
+  
+  // Initialize the pragma handlers.
+  PragmaHandlers = new PragmaNamespace(StringRef());
+  RegisterBuiltinPragmas();
+  
+  // Initialize builtin macros like __LINE__ and friends.
+  RegisterBuiltinMacros();
+  
+  if(LangOpts.Borland) {
+    Ident__exception_info        = getIdentifierInfo("_exception_info");
+    Ident___exception_info       = getIdentifierInfo("__exception_info");
+    Ident_GetExceptionInfo       = getIdentifierInfo("GetExceptionInformation");
+    Ident__exception_code        = getIdentifierInfo("_exception_code");
+    Ident___exception_code       = getIdentifierInfo("__exception_code");
+    Ident_GetExceptionCode       = getIdentifierInfo("GetExceptionCode");
+    Ident__abnormal_termination  = getIdentifierInfo("_abnormal_termination");
+    Ident___abnormal_termination = getIdentifierInfo("__abnormal_termination");
+    Ident_AbnormalTermination    = getIdentifierInfo("AbnormalTermination");
+  } else {
+    Ident__exception_info = Ident__exception_code = Ident__abnormal_termination = 0;
+    Ident___exception_info = Ident___exception_code = Ident___abnormal_termination = 0;
+    Ident_GetExceptionInfo = Ident_GetExceptionCode = Ident_AbnormalTermination = 0;
+  }
+  
+  HeaderInfo.setTarget(Target);
+}
+
+void Preprocessor::setPTHManager(PTHManager* pm) {
+  PTH.reset(pm);
+  FileMgr.addStatCache(PTH->createStatCache());
+}
+
+void Preprocessor::DumpToken(const Token &Tok, bool DumpFlags) const {
+  llvm::errs() << tok::getTokenName(Tok.getKind()) << " '"
+               << getSpelling(Tok) << "'";
+
+  if (!DumpFlags) return;
+
+  llvm::errs() << "\t";
+  if (Tok.isAtStartOfLine())
+    llvm::errs() << " [StartOfLine]";
+  if (Tok.hasLeadingSpace())
+    llvm::errs() << " [LeadingSpace]";
+  if (Tok.isExpandDisabled())
+    llvm::errs() << " [ExpandDisabled]";
+  if (Tok.needsCleaning()) {
+    const char *Start = SourceMgr.getCharacterData(Tok.getLocation());
+    llvm::errs() << " [UnClean='" << StringRef(Start, Tok.getLength())
+                 << "']";
+  }
+
+  llvm::errs() << "\tLoc=<";
+  DumpLocation(Tok.getLocation());
+  llvm::errs() << ">";
+}
+
+void Preprocessor::DumpLocation(SourceLocation Loc) const {
+  Loc.dump(SourceMgr);
+}
+
+void Preprocessor::DumpMacro(const MacroInfo &MI) const {
+  llvm::errs() << "MACRO: ";
+  for (unsigned i = 0, e = MI.getNumTokens(); i != e; ++i) {
+    DumpToken(MI.getReplacementToken(i));
+    llvm::errs() << "  ";
+  }
+  llvm::errs() << "\n";
+}
+
+void Preprocessor::PrintStats() {
+  llvm::errs() << "\n*** Preprocessor Stats:\n";
+  llvm::errs() << NumDirectives << " directives found:\n";
+  llvm::errs() << "  " << NumDefined << " #define.\n";
+  llvm::errs() << "  " << NumUndefined << " #undef.\n";
+  llvm::errs() << "  #include/#include_next/#import:\n";
+  llvm::errs() << "    " << NumEnteredSourceFiles << " source files entered.\n";
+  llvm::errs() << "    " << MaxIncludeStackDepth << " max include stack depth\n";
+  llvm::errs() << "  " << NumIf << " #if/#ifndef/#ifdef.\n";
+  llvm::errs() << "  " << NumElse << " #else/#elif.\n";
+  llvm::errs() << "  " << NumEndif << " #endif.\n";
+  llvm::errs() << "  " << NumPragma << " #pragma.\n";
+  llvm::errs() << NumSkipped << " #if/#ifndef#ifdef regions skipped\n";
+
+  llvm::errs() << NumMacroExpanded << "/" << NumFnMacroExpanded << "/"
+             << NumBuiltinMacroExpanded << " obj/fn/builtin macros expanded, "
+             << NumFastMacroExpanded << " on the fast path.\n";
+  llvm::errs() << (NumFastTokenPaste+NumTokenPaste)
+             << " token paste (##) operations performed, "
+             << NumFastTokenPaste << " on the fast path.\n";
+}
+
+Preprocessor::macro_iterator
+Preprocessor::macro_begin(bool IncludeExternalMacros) const {
+  if (IncludeExternalMacros && ExternalSource &&
+      !ReadMacrosFromExternalSource) {
+    ReadMacrosFromExternalSource = true;
+    ExternalSource->ReadDefinedMacros();
+  }
+
+  return Macros.begin();
+}
+
+size_t Preprocessor::getTotalMemory() const {
+  return BP.getTotalMemory()
+    + llvm::capacity_in_bytes(MacroExpandedTokens)
+    + Predefines.capacity() /* Predefines buffer. */
+    + llvm::capacity_in_bytes(Macros)
+    + llvm::capacity_in_bytes(PragmaPushMacroInfo)
+    + llvm::capacity_in_bytes(PoisonReasons)
+    + llvm::capacity_in_bytes(CommentHandlers);
+}
+
+Preprocessor::macro_iterator
+Preprocessor::macro_end(bool IncludeExternalMacros) const {
+  if (IncludeExternalMacros && ExternalSource &&
+      !ReadMacrosFromExternalSource) {
+    ReadMacrosFromExternalSource = true;
+    ExternalSource->ReadDefinedMacros();
+  }
+
+  return Macros.end();
+}
+
+void Preprocessor::recomputeCurLexerKind() {
+  if (CurLexer)
+    CurLexerKind = CLK_Lexer;
+  else if (CurPTHLexer)
+    CurLexerKind = CLK_PTHLexer;
+  else if (CurTokenLexer)
+    CurLexerKind = CLK_TokenLexer;
+  else 
+    CurLexerKind = CLK_CachingLexer;
+}
+
+bool Preprocessor::SetCodeCompletionPoint(const FileEntry *File,
+                                          unsigned CompleteLine,
+                                          unsigned CompleteColumn) {
+  assert(File);
+  assert(CompleteLine && CompleteColumn && "Starts from 1:1");
+  assert(!CodeCompletionFile && "Already set");
+
+  using llvm::MemoryBuffer;
+
+  // Load the actual file's contents.
+  bool Invalid = false;
+  const MemoryBuffer *Buffer = SourceMgr.getMemoryBufferForFile(File, &Invalid);
+  if (Invalid)
+    return true;
+
+  // Find the byte position of the truncation point.
+  const char *Position = Buffer->getBufferStart();
+  for (unsigned Line = 1; Line < CompleteLine; ++Line) {
+    for (; *Position; ++Position) {
+      if (*Position != '\r' && *Position != '\n')
+        continue;
+
+      // Eat \r\n or \n\r as a single line.
+      if ((Position[1] == '\r' || Position[1] == '\n') &&
+          Position[0] != Position[1])
+        ++Position;
+      ++Position;
+      break;
+    }
+  }
+
+  Position += CompleteColumn - 1;
+
+  // Insert '\0' at the code-completion point.
+  if (Position < Buffer->getBufferEnd()) {
+    CodeCompletionFile = File;
+    CodeCompletionOffset = Position - Buffer->getBufferStart();
+
+    MemoryBuffer *NewBuffer =
+        MemoryBuffer::getNewUninitMemBuffer(Buffer->getBufferSize() + 1,
+                                            Buffer->getBufferIdentifier());
+    char *NewBuf = const_cast<char*>(NewBuffer->getBufferStart());
+    char *NewPos = std::copy(Buffer->getBufferStart(), Position, NewBuf);
+    *NewPos = '\0';
+    std::copy(Position, Buffer->getBufferEnd(), NewPos+1);
+    SourceMgr.overrideFileContents(File, NewBuffer);
+  }
+
+  return false;
+}
+
+void Preprocessor::CodeCompleteNaturalLanguage() {
+  if (CodeComplete)
+    CodeComplete->CodeCompleteNaturalLanguage();
+  setCodeCompletionReached();
+}
+
+/// getSpelling - This method is used to get the spelling of a token into a
+/// SmallVector. Note that the returned StringRef may not point to the
+/// supplied buffer if a copy can be avoided.
+StringRef Preprocessor::getSpelling(const Token &Tok,
+                                          SmallVectorImpl<char> &Buffer,
+                                          bool *Invalid) const {
+  // NOTE: this has to be checked *before* testing for an IdentifierInfo.
+  if (Tok.isNot(tok::raw_identifier)) {
+    // Try the fast path.
+    if (const IdentifierInfo *II = Tok.getIdentifierInfo())
+      return II->getName();
+  }
+
+  // Resize the buffer if we need to copy into it.
+  if (Tok.needsCleaning())
+    Buffer.resize(Tok.getLength());
+
+  const char *Ptr = Buffer.data();
+  unsigned Len = getSpelling(Tok, Ptr, Invalid);
+  return StringRef(Ptr, Len);
+}
+
+/// CreateString - Plop the specified string into a scratch buffer and return a
+/// location for it.  If specified, the source location provides a source
+/// location for the token.
+void Preprocessor::CreateString(const char *Buf, unsigned Len, Token &Tok,
+                                SourceLocation ExpansionLocStart,
+                                SourceLocation ExpansionLocEnd) {
+  Tok.setLength(Len);
+
+  const char *DestPtr;
+  SourceLocation Loc = ScratchBuf->getToken(Buf, Len, DestPtr);
+
+  if (ExpansionLocStart.isValid())
+    Loc = SourceMgr.createExpansionLoc(Loc, ExpansionLocStart,
+                                       ExpansionLocEnd, Len);
+  Tok.setLocation(Loc);
+
+  // If this is a raw identifier or a literal token, set the pointer data.
+  if (Tok.is(tok::raw_identifier))
+    Tok.setRawIdentifierData(DestPtr);
+  else if (Tok.isLiteral())
+    Tok.setLiteralData(DestPtr);
+}
+
+Module *Preprocessor::getCurrentModule() {
+  if (getLangOpts().CurrentModule.empty())
+    return 0;
+  
+  return getHeaderSearchInfo().lookupModule(getLangOpts().CurrentModule);
+}
+
+//===----------------------------------------------------------------------===//
+// Preprocessor Initialization Methods
+//===----------------------------------------------------------------------===//
+
+
+/// EnterMainSourceFile - Enter the specified FileID as the main source file,
+/// which implicitly adds the builtin defines etc.
+void Preprocessor::EnterMainSourceFile() {
+  // We do not allow the preprocessor to reenter the main file.  Doing so will
+  // cause FileID's to accumulate information from both runs (e.g. #line
+  // information) and predefined macros aren't guaranteed to be set properly.
+  assert(NumEnteredSourceFiles == 0 && "Cannot reenter the main file!");
+  FileID MainFileID = SourceMgr.getMainFileID();
+
+  // If MainFileID is loaded it means we loaded an AST file, no need to enter
+  // a main file.
+  if (!SourceMgr.isLoadedFileID(MainFileID)) {
+    // Enter the main file source buffer.
+    EnterSourceFile(MainFileID, 0, SourceLocation());
+  
+    // If we've been asked to skip bytes in the main file (e.g., as part of a
+    // precompiled preamble), do so now.
+    if (SkipMainFilePreamble.first > 0)
+      CurLexer->SkipBytes(SkipMainFilePreamble.first, 
+                          SkipMainFilePreamble.second);
+    
+    // Tell the header info that the main file was entered.  If the file is later
+    // #imported, it won't be re-entered.
+    if (const FileEntry *FE = SourceMgr.getFileEntryForID(MainFileID))
+      HeaderInfo.IncrementIncludeCount(FE);
+  }
+
+  // Preprocess Predefines to populate the initial preprocessor state.
+  llvm::MemoryBuffer *SB =
+    llvm::MemoryBuffer::getMemBufferCopy(Predefines, "<built-in>");
+  assert(SB && "Cannot create predefined source buffer");
+  FileID FID = SourceMgr.createFileIDForMemBuffer(SB);
+  assert(!FID.isInvalid() && "Could not create FileID for predefines?");
+
+  // Start parsing the predefines.
+  EnterSourceFile(FID, 0, SourceLocation());
+}
+
+void Preprocessor::EndSourceFile() {
+  // Notify the client that we reached the end of the source file.
+  if (Callbacks)
+    Callbacks->EndOfMainFile();
+}
+
+//===----------------------------------------------------------------------===//
+// Lexer Event Handling.
+//===----------------------------------------------------------------------===//
+
+/// LookUpIdentifierInfo - Given a tok::raw_identifier token, look up the
+/// identifier information for the token and install it into the token,
+/// updating the token kind accordingly.
+IdentifierInfo *Preprocessor::LookUpIdentifierInfo(Token &Identifier) const {
+  assert(Identifier.getRawIdentifierData() != 0 && "No raw identifier data!");
+
+  // Look up this token, see if it is a macro, or if it is a language keyword.
+  IdentifierInfo *II;
+  if (!Identifier.needsCleaning()) {
+    // No cleaning needed, just use the characters from the lexed buffer.
+    II = getIdentifierInfo(StringRef(Identifier.getRawIdentifierData(),
+                                           Identifier.getLength()));
+  } else {
+    // Cleaning needed, alloca a buffer, clean into it, then use the buffer.
+    SmallString<64> IdentifierBuffer;
+    StringRef CleanedStr = getSpelling(Identifier, IdentifierBuffer);
+    II = getIdentifierInfo(CleanedStr);
+  }
+
+  // Update the token info (identifier info and appropriate token kind).
+  Identifier.setIdentifierInfo(II);
+  Identifier.setKind(II->getTokenID());
+
+  return II;
+}
+
+void Preprocessor::SetPoisonReason(IdentifierInfo *II, unsigned DiagID) {
+  PoisonReasons[II] = DiagID;
+}
+
+void Preprocessor::PoisonSEHIdentifiers(bool Poison) {
+  assert(Ident__exception_code && Ident__exception_info);
+  assert(Ident___exception_code && Ident___exception_info);
+  Ident__exception_code->setIsPoisoned(Poison);
+  Ident___exception_code->setIsPoisoned(Poison);
+  Ident_GetExceptionCode->setIsPoisoned(Poison);
+  Ident__exception_info->setIsPoisoned(Poison);
+  Ident___exception_info->setIsPoisoned(Poison);
+  Ident_GetExceptionInfo->setIsPoisoned(Poison);
+  Ident__abnormal_termination->setIsPoisoned(Poison);
+  Ident___abnormal_termination->setIsPoisoned(Poison);
+  Ident_AbnormalTermination->setIsPoisoned(Poison);
+}
+
+void Preprocessor::HandlePoisonedIdentifier(Token & Identifier) {
+  assert(Identifier.getIdentifierInfo() &&
+         "Can't handle identifiers without identifier info!");
+  llvm::DenseMap<IdentifierInfo*,unsigned>::const_iterator it =
+    PoisonReasons.find(Identifier.getIdentifierInfo());
+  if(it == PoisonReasons.end())
+    Diag(Identifier, diag::err_pp_used_poisoned_id);
+  else
+    Diag(Identifier,it->second) << Identifier.getIdentifierInfo();
+}
+
+/// HandleIdentifier - This callback is invoked when the lexer reads an
+/// identifier.  This callback looks up the identifier in the map and/or
+/// potentially macro expands it or turns it into a named token (like 'for').
+///
+/// Note that callers of this method are guarded by checking the
+/// IdentifierInfo's 'isHandleIdentifierCase' bit.  If this method changes, the
+/// IdentifierInfo methods that compute these properties will need to change to
+/// match.
+void Preprocessor::HandleIdentifier(Token &Identifier) {
+  assert(Identifier.getIdentifierInfo() &&
+         "Can't handle identifiers without identifier info!");
+
+  IdentifierInfo &II = *Identifier.getIdentifierInfo();
+
+  // If the information about this identifier is out of date, update it from
+  // the external source.
+  if (II.isOutOfDate()) {
+    ExternalSource->updateOutOfDateIdentifier(II);
+    Identifier.setKind(II.getTokenID());
+  }
+  
+  // If this identifier was poisoned, and if it was not produced from a macro
+  // expansion, emit an error.
+  if (II.isPoisoned() && CurPPLexer) {
+    HandlePoisonedIdentifier(Identifier);
+  }
+
+  // If this is a macro to be expanded, do it.
+  if (MacroInfo *MI = getMacroInfo(&II)) {
+    if (!DisableMacroExpansion) {
+      if (Identifier.isExpandDisabled()) {
+        Diag(Identifier, diag::pp_disabled_macro_expansion);
+      } else if (MI->isEnabled()) {
+        if (!HandleMacroExpandedIdentifier(Identifier, MI))
+          return;
+      } else {
+        // C99 6.10.3.4p2 says that a disabled macro may never again be
+        // expanded, even if it's in a context where it could be expanded in the
+        // future.
+        Identifier.setFlag(Token::DisableExpand);
+        Diag(Identifier, diag::pp_disabled_macro_expansion);
+      }
+    }
+  }
+
+  // If this identifier is a keyword in C++11, produce a warning. Don't warn if
+  // we're not considering macro expansion, since this identifier might be the
+  // name of a macro.
+  // FIXME: This warning is disabled in cases where it shouldn't be, like
+  //   "#define constexpr constexpr", "int constexpr;"
+  if (II.isCXX11CompatKeyword() & !DisableMacroExpansion) {
+    Diag(Identifier, diag::warn_cxx11_keyword) << II.getName();
+    // Don't diagnose this keyword again in this translation unit.
+    II.setIsCXX11CompatKeyword(false);
+  }
+
+  // C++ 2.11p2: If this is an alternative representation of a C++ operator,
+  // then we act as if it is the actual operator and not the textual
+  // representation of it.
+  if (II.isCPlusPlusOperatorKeyword())
+    Identifier.setIdentifierInfo(0);
+
+  // If this is an extension token, diagnose its use.
+  // We avoid diagnosing tokens that originate from macro definitions.
+  // FIXME: This warning is disabled in cases where it shouldn't be,
+  // like "#define TY typeof", "TY(1) x".
+  if (II.isExtensionToken() && !DisableMacroExpansion)
+    Diag(Identifier, diag::ext_token_used);
+  
+  // If this is the '__experimental_modules_import' contextual keyword, note
+  // that the next token indicates a module name.
+  //
+  // Note that we do not treat '__experimental_modules_import' as a contextual
+  // keyword when we're in a caching lexer, because caching lexers only get
+  // used in contexts where import declarations are disallowed.
+  if (II.isModulesImport() && !InMacroArgs && !DisableMacroExpansion &&
+      getLangOpts().Modules && CurLexerKind != CLK_CachingLexer) {
+    ModuleImportLoc = Identifier.getLocation();
+    ModuleImportPath.clear();
+    ModuleImportExpectsIdentifier = true;
+    CurLexerKind = CLK_LexAfterModuleImport;
+  }
+}
+
+/// \brief Lex a token following the 'import' contextual keyword.
+///
+void Preprocessor::LexAfterModuleImport(Token &Result) {
+  // Figure out what kind of lexer we actually have.
+  recomputeCurLexerKind();
+  
+  // Lex the next token.
+  Lex(Result);
+
+  // The token sequence 
+  //
+  //   import identifier (. identifier)*
+  //
+  // indicates a module import directive. We already saw the 'import' 
+  // contextual keyword, so now we're looking for the identifiers.
+  if (ModuleImportExpectsIdentifier && Result.getKind() == tok::identifier) {
+    // We expected to see an identifier here, and we did; continue handling
+    // identifiers.
+    ModuleImportPath.push_back(std::make_pair(Result.getIdentifierInfo(),
+                                              Result.getLocation()));
+    ModuleImportExpectsIdentifier = false;
+    CurLexerKind = CLK_LexAfterModuleImport;
+    return;
+  }
+  
+  // If we're expecting a '.' or a ';', and we got a '.', then wait until we
+  // see the next identifier.
+  if (!ModuleImportExpectsIdentifier && Result.getKind() == tok::period) {
+    ModuleImportExpectsIdentifier = true;
+    CurLexerKind = CLK_LexAfterModuleImport;
+    return;
+  }
+
+  // If we have a non-empty module path, load the named module.
+  if (!ModuleImportPath.empty())
+    (void)TheModuleLoader.loadModule(ModuleImportLoc, ModuleImportPath,
+                                     Module::MacrosVisible,
+                                     /*IsIncludeDirective=*/false);
+}
+
+void Preprocessor::AddCommentHandler(CommentHandler *Handler) {
+  assert(Handler && "NULL comment handler");
+  assert(std::find(CommentHandlers.begin(), CommentHandlers.end(), Handler) ==
+         CommentHandlers.end() && "Comment handler already registered");
+  CommentHandlers.push_back(Handler);
+}
+
+void Preprocessor::RemoveCommentHandler(CommentHandler *Handler) {
+  std::vector<CommentHandler *>::iterator Pos
+  = std::find(CommentHandlers.begin(), CommentHandlers.end(), Handler);
+  assert(Pos != CommentHandlers.end() && "Comment handler not registered");
+  CommentHandlers.erase(Pos);
+}
+
+bool Preprocessor::HandleComment(Token &result, SourceRange Comment) {
+  bool AnyPendingTokens = false;
+  for (std::vector<CommentHandler *>::iterator H = CommentHandlers.begin(),
+       HEnd = CommentHandlers.end();
+       H != HEnd; ++H) {
+    if ((*H)->HandleComment(*this, Comment))
+      AnyPendingTokens = true;
+  }
+  if (!AnyPendingTokens || getCommentRetentionState())
+    return false;
+  Lex(result);
+  return true;
+}
+
+ModuleLoader::~ModuleLoader() { }
+
+CommentHandler::~CommentHandler() { }
+
+CodeCompletionHandler::~CodeCompletionHandler() { }
+
+void Preprocessor::createPreprocessingRecord(bool RecordConditionalDirectives) {
+  if (Record)
+    return;
+  
+  Record = new PreprocessingRecord(getSourceManager(),
+                                   RecordConditionalDirectives);
+  addPPCallbacks(Record);
+}