Merge branch 'master' of ssh://bitbucket.org/czan/honours

1 files changed, 1292 insertions, 0 deletions

diff --git a/clang/lib/Lex/Pragma.cpp b/clang/lib/Lex/Pragma.cpp
new file mode 100644
index 0000000..e2a192b
--- /dev/null
+++ b/clang/lib/Lex/Pragma.cpp
@@ -0,0 +1,1292 @@
+//===--- Pragma.cpp - Pragma registration and handling --------------------===//
+//
+//                     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 PragmaHandler/PragmaTable interfaces and implements
+// pragma related methods of the Preprocessor class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Lex/Pragma.h"
+#include "clang/Lex/HeaderSearch.h"
+#include "clang/Lex/LiteralSupport.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Lex/MacroInfo.h"
+#include "clang/Lex/LexDiagnostic.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/SourceManager.h"
+#include "llvm/Support/CrashRecoveryContext.h"
+#include "llvm/Support/ErrorHandling.h"
+#include <algorithm>
+using namespace clang;
+
+// Out-of-line destructor to provide a home for the class.
+PragmaHandler::~PragmaHandler() {
+}
+
+//===----------------------------------------------------------------------===//
+// EmptyPragmaHandler Implementation.
+//===----------------------------------------------------------------------===//
+
+EmptyPragmaHandler::EmptyPragmaHandler() {}
+
+void EmptyPragmaHandler::HandlePragma(Preprocessor &PP, 
+                                      PragmaIntroducerKind Introducer,
+                                      Token &FirstToken) {}
+
+//===----------------------------------------------------------------------===//
+// PragmaNamespace Implementation.
+//===----------------------------------------------------------------------===//
+
+
+PragmaNamespace::~PragmaNamespace() {
+  for (llvm::StringMap<PragmaHandler*>::iterator
+         I = Handlers.begin(), E = Handlers.end(); I != E; ++I)
+    delete I->second;
+}
+
+/// FindHandler - Check to see if there is already a handler for the
+/// specified name.  If not, return the handler for the null identifier if it
+/// exists, otherwise return null.  If IgnoreNull is true (the default) then
+/// the null handler isn't returned on failure to match.
+PragmaHandler *PragmaNamespace::FindHandler(StringRef Name,
+                                            bool IgnoreNull) const {
+  if (PragmaHandler *Handler = Handlers.lookup(Name))
+    return Handler;
+  return IgnoreNull ? 0 : Handlers.lookup(StringRef());
+}
+
+void PragmaNamespace::AddPragma(PragmaHandler *Handler) {
+  assert(!Handlers.lookup(Handler->getName()) &&
+         "A handler with this name is already registered in this namespace");
+  llvm::StringMapEntry<PragmaHandler *> &Entry =
+    Handlers.GetOrCreateValue(Handler->getName());
+  Entry.setValue(Handler);
+}
+
+void PragmaNamespace::RemovePragmaHandler(PragmaHandler *Handler) {
+  assert(Handlers.lookup(Handler->getName()) &&
+         "Handler not registered in this namespace");
+  Handlers.erase(Handler->getName());
+}
+
+void PragmaNamespace::HandlePragma(Preprocessor &PP, 
+                                   PragmaIntroducerKind Introducer,
+                                   Token &Tok) {
+  // Read the 'namespace' that the directive is in, e.g. STDC.  Do not macro
+  // expand it, the user can have a STDC #define, that should not affect this.
+  PP.LexUnexpandedToken(Tok);
+
+  // Get the handler for this token.  If there is no handler, ignore the pragma.
+  PragmaHandler *Handler
+    = FindHandler(Tok.getIdentifierInfo() ? Tok.getIdentifierInfo()->getName()
+                                          : StringRef(),
+                  /*IgnoreNull=*/false);
+  if (Handler == 0) {
+    PP.Diag(Tok, diag::warn_pragma_ignored);
+    return;
+  }
+
+  // Otherwise, pass it down.
+  Handler->HandlePragma(PP, Introducer, Tok);
+}
+
+//===----------------------------------------------------------------------===//
+// Preprocessor Pragma Directive Handling.
+//===----------------------------------------------------------------------===//
+
+/// HandlePragmaDirective - The "#pragma" directive has been parsed.  Lex the
+/// rest of the pragma, passing it to the registered pragma handlers.
+void Preprocessor::HandlePragmaDirective(unsigned Introducer) {
+  ++NumPragma;
+
+  // Invoke the first level of pragma handlers which reads the namespace id.
+  Token Tok;
+  PragmaHandlers->HandlePragma(*this, PragmaIntroducerKind(Introducer), Tok);
+
+  // If the pragma handler didn't read the rest of the line, consume it now.
+  if ((CurTokenLexer && CurTokenLexer->isParsingPreprocessorDirective()) 
+   || (CurPPLexer && CurPPLexer->ParsingPreprocessorDirective))
+    DiscardUntilEndOfDirective();
+}
+
+namespace {
+/// \brief Helper class for \see Preprocessor::Handle_Pragma.
+class LexingFor_PragmaRAII {
+  Preprocessor &PP;
+  bool InMacroArgPreExpansion;
+  bool Failed;
+  Token &OutTok;
+  Token PragmaTok;
+
+public:
+  LexingFor_PragmaRAII(Preprocessor &PP, bool InMacroArgPreExpansion,
+                       Token &Tok)
+    : PP(PP), InMacroArgPreExpansion(InMacroArgPreExpansion),
+      Failed(false), OutTok(Tok) {
+    if (InMacroArgPreExpansion) {
+      PragmaTok = OutTok;
+      PP.EnableBacktrackAtThisPos();
+    }
+  }
+
+  ~LexingFor_PragmaRAII() {
+    if (InMacroArgPreExpansion) {
+      if (Failed) {
+        PP.CommitBacktrackedTokens();
+      } else {
+        PP.Backtrack();
+        OutTok = PragmaTok;
+      }
+    }
+  }
+
+  void failed() {
+    Failed = true;
+  }
+};
+}
+
+/// Handle_Pragma - Read a _Pragma directive, slice it up, process it, then
+/// return the first token after the directive.  The _Pragma token has just
+/// been read into 'Tok'.
+void Preprocessor::Handle_Pragma(Token &Tok) {
+
+  // This works differently if we are pre-expanding a macro argument.
+  // In that case we don't actually "activate" the pragma now, we only lex it
+  // until we are sure it is lexically correct and then we backtrack so that
+  // we activate the pragma whenever we encounter the tokens again in the token
+  // stream. This ensures that we will activate it in the correct location
+  // or that we will ignore it if it never enters the token stream, e.g:
+  //
+  //     #define EMPTY(x)
+  //     #define INACTIVE(x) EMPTY(x)
+  //     INACTIVE(_Pragma("clang diagnostic ignored \"-Wconversion\""))
+
+  LexingFor_PragmaRAII _PragmaLexing(*this, InMacroArgPreExpansion, Tok);
+
+  // Remember the pragma token location.
+  SourceLocation PragmaLoc = Tok.getLocation();
+
+  // Read the '('.
+  Lex(Tok);
+  if (Tok.isNot(tok::l_paren)) {
+    Diag(PragmaLoc, diag::err__Pragma_malformed);
+    return _PragmaLexing.failed();
+  }
+
+  // Read the '"..."'.
+  Lex(Tok);
+  if (Tok.isNot(tok::string_literal) && Tok.isNot(tok::wide_string_literal)) {
+    Diag(PragmaLoc, diag::err__Pragma_malformed);
+    // Skip this token, and the ')', if present.
+    if (Tok.isNot(tok::r_paren))
+      Lex(Tok);
+    if (Tok.is(tok::r_paren))
+      Lex(Tok);
+    return _PragmaLexing.failed();
+  }
+
+  if (Tok.hasUDSuffix()) {
+    Diag(Tok, diag::err_invalid_string_udl);
+    // Skip this token, and the ')', if present.
+    Lex(Tok);
+    if (Tok.is(tok::r_paren))
+      Lex(Tok);
+    return _PragmaLexing.failed();
+  }
+
+  // Remember the string.
+  Token StrTok = Tok;
+
+  // Read the ')'.
+  Lex(Tok);
+  if (Tok.isNot(tok::r_paren)) {
+    Diag(PragmaLoc, diag::err__Pragma_malformed);
+    return _PragmaLexing.failed();
+  }
+
+  if (InMacroArgPreExpansion)
+    return;
+
+  SourceLocation RParenLoc = Tok.getLocation();
+  std::string StrVal = getSpelling(StrTok);
+
+  // The _Pragma is lexically sound.  Destringize according to C99 6.10.9.1:
+  // "The string literal is destringized by deleting the L prefix, if present,
+  // deleting the leading and trailing double-quotes, replacing each escape
+  // sequence \" by a double-quote, and replacing each escape sequence \\ by a
+  // single backslash."
+  if (StrVal[0] == 'L')  // Remove L prefix.
+    StrVal.erase(StrVal.begin());
+  assert(StrVal[0] == '"' && StrVal[StrVal.size()-1] == '"' &&
+         "Invalid string token!");
+
+  // Remove the front quote, replacing it with a space, so that the pragma
+  // contents appear to have a space before them.
+  StrVal[0] = ' ';
+
+  // Replace the terminating quote with a \n.
+  StrVal[StrVal.size()-1] = '\n';
+
+  // Remove escaped quotes and escapes.
+  for (unsigned i = 0, e = StrVal.size(); i != e-1; ++i) {
+    if (StrVal[i] == '\\' &&
+        (StrVal[i+1] == '\\' || StrVal[i+1] == '"')) {
+      // \\ -> '\' and \" -> '"'.
+      StrVal.erase(StrVal.begin()+i);
+      --e;
+    }
+  }
+  
+  // Plop the string (including the newline and trailing null) into a buffer
+  // where we can lex it.
+  Token TmpTok;
+  TmpTok.startToken();
+  CreateString(&StrVal[0], StrVal.size(), TmpTok);
+  SourceLocation TokLoc = TmpTok.getLocation();
+
+  // Make and enter a lexer object so that we lex and expand the tokens just
+  // like any others.
+  Lexer *TL = Lexer::Create_PragmaLexer(TokLoc, PragmaLoc, RParenLoc,
+                                        StrVal.size(), *this);
+
+  EnterSourceFileWithLexer(TL, 0);
+
+  // With everything set up, lex this as a #pragma directive.
+  HandlePragmaDirective(PIK__Pragma);
+
+  // Finally, return whatever came after the pragma directive.
+  return Lex(Tok);
+}
+
+/// HandleMicrosoft__pragma - Like Handle_Pragma except the pragma text
+/// is not enclosed within a string literal.
+void Preprocessor::HandleMicrosoft__pragma(Token &Tok) {
+  // Remember the pragma token location.
+  SourceLocation PragmaLoc = Tok.getLocation();
+
+  // Read the '('.
+  Lex(Tok);
+  if (Tok.isNot(tok::l_paren)) {
+    Diag(PragmaLoc, diag::err__Pragma_malformed);
+    return;
+  }
+
+  // Get the tokens enclosed within the __pragma(), as well as the final ')'.
+  SmallVector<Token, 32> PragmaToks;
+  int NumParens = 0;
+  Lex(Tok);
+  while (Tok.isNot(tok::eof)) {
+    PragmaToks.push_back(Tok);
+    if (Tok.is(tok::l_paren))
+      NumParens++;
+    else if (Tok.is(tok::r_paren) && NumParens-- == 0)
+      break;
+    Lex(Tok);
+  }
+
+  if (Tok.is(tok::eof)) {
+    Diag(PragmaLoc, diag::err_unterminated___pragma);
+    return;
+  }
+
+  PragmaToks.front().setFlag(Token::LeadingSpace);
+
+  // Replace the ')' with an EOD to mark the end of the pragma.
+  PragmaToks.back().setKind(tok::eod);
+
+  Token *TokArray = new Token[PragmaToks.size()];
+  std::copy(PragmaToks.begin(), PragmaToks.end(), TokArray);
+
+  // Push the tokens onto the stack.
+  EnterTokenStream(TokArray, PragmaToks.size(), true, true);
+
+  // With everything set up, lex this as a #pragma directive.
+  HandlePragmaDirective(PIK___pragma);
+
+  // Finally, return whatever came after the pragma directive.
+  return Lex(Tok);
+}
+
+/// HandlePragmaOnce - Handle #pragma once.  OnceTok is the 'once'.
+///
+void Preprocessor::HandlePragmaOnce(Token &OnceTok) {
+  if (isInPrimaryFile()) {
+    Diag(OnceTok, diag::pp_pragma_once_in_main_file);
+    return;
+  }
+
+  // Get the current file lexer we're looking at.  Ignore _Pragma 'files' etc.
+  // Mark the file as a once-only file now.
+  HeaderInfo.MarkFileIncludeOnce(getCurrentFileLexer()->getFileEntry());
+}
+
+void Preprocessor::HandlePragmaMark() {
+  assert(CurPPLexer && "No current lexer?");
+  if (CurLexer)
+    CurLexer->ReadToEndOfLine();
+  else
+    CurPTHLexer->DiscardToEndOfLine();
+}
+
+
+/// HandlePragmaPoison - Handle #pragma GCC poison.  PoisonTok is the 'poison'.
+///
+void Preprocessor::HandlePragmaPoison(Token &PoisonTok) {
+  Token Tok;
+
+  while (1) {
+    // Read the next token to poison.  While doing this, pretend that we are
+    // skipping while reading the identifier to poison.
+    // This avoids errors on code like:
+    //   #pragma GCC poison X
+    //   #pragma GCC poison X
+    if (CurPPLexer) CurPPLexer->LexingRawMode = true;
+    LexUnexpandedToken(Tok);
+    if (CurPPLexer) CurPPLexer->LexingRawMode = false;
+
+    // If we reached the end of line, we're done.
+    if (Tok.is(tok::eod)) return;
+
+    // Can only poison identifiers.
+    if (Tok.isNot(tok::raw_identifier)) {
+      Diag(Tok, diag::err_pp_invalid_poison);
+      return;
+    }
+
+    // Look up the identifier info for the token.  We disabled identifier lookup
+    // by saying we're skipping contents, so we need to do this manually.
+    IdentifierInfo *II = LookUpIdentifierInfo(Tok);
+
+    // Already poisoned.
+    if (II->isPoisoned()) continue;
+
+    // If this is a macro identifier, emit a warning.
+    if (II->hasMacroDefinition())
+      Diag(Tok, diag::pp_poisoning_existing_macro);
+
+    // Finally, poison it!
+    II->setIsPoisoned();
+    if (II->isFromAST())
+      II->setChangedSinceDeserialization();
+  }
+}
+
+/// HandlePragmaSystemHeader - Implement #pragma GCC system_header.  We know
+/// that the whole directive has been parsed.
+void Preprocessor::HandlePragmaSystemHeader(Token &SysHeaderTok) {
+  if (isInPrimaryFile()) {
+    Diag(SysHeaderTok, diag::pp_pragma_sysheader_in_main_file);
+    return;
+  }
+
+  // Get the current file lexer we're looking at.  Ignore _Pragma 'files' etc.
+  PreprocessorLexer *TheLexer = getCurrentFileLexer();
+
+  // Mark the file as a system header.
+  HeaderInfo.MarkFileSystemHeader(TheLexer->getFileEntry());
+
+
+  PresumedLoc PLoc = SourceMgr.getPresumedLoc(SysHeaderTok.getLocation());
+  if (PLoc.isInvalid())
+    return;
+  
+  unsigned FilenameID = SourceMgr.getLineTableFilenameID(PLoc.getFilename());
+
+  // Notify the client, if desired, that we are in a new source file.
+  if (Callbacks)
+    Callbacks->FileChanged(SysHeaderTok.getLocation(),
+                           PPCallbacks::SystemHeaderPragma, SrcMgr::C_System);
+
+  // Emit a line marker.  This will change any source locations from this point
+  // forward to realize they are in a system header.
+  // Create a line note with this information.
+  SourceMgr.AddLineNote(SysHeaderTok.getLocation(), PLoc.getLine(), FilenameID,
+                        false, false, true, false);
+}
+
+/// HandlePragmaDependency - Handle #pragma GCC dependency "foo" blah.
+///
+void Preprocessor::HandlePragmaDependency(Token &DependencyTok) {
+  Token FilenameTok;
+  CurPPLexer->LexIncludeFilename(FilenameTok);
+
+  // If the token kind is EOD, the error has already been diagnosed.
+  if (FilenameTok.is(tok::eod))
+    return;
+
+  // Reserve a buffer to get the spelling.
+  SmallString<128> FilenameBuffer;
+  bool Invalid = false;
+  StringRef Filename = getSpelling(FilenameTok, FilenameBuffer, &Invalid);
+  if (Invalid)
+    return;
+
+  bool isAngled =
+    GetIncludeFilenameSpelling(FilenameTok.getLocation(), Filename);
+  // If GetIncludeFilenameSpelling set the start ptr to null, there was an
+  // error.
+  if (Filename.empty())
+    return;
+
+  // Search include directories for this file.
+  const DirectoryLookup *CurDir;
+  const FileEntry *File = LookupFile(Filename, isAngled, 0, CurDir, NULL, NULL,
+                                     NULL);
+  if (File == 0) {
+    if (!SuppressIncludeNotFoundError)
+      Diag(FilenameTok, diag::err_pp_file_not_found) << Filename;
+    return;
+  }
+
+  const FileEntry *CurFile = getCurrentFileLexer()->getFileEntry();
+
+  // If this file is older than the file it depends on, emit a diagnostic.
+  if (CurFile && CurFile->getModificationTime() < File->getModificationTime()) {
+    // Lex tokens at the end of the message and include them in the message.
+    std::string Message;
+    Lex(DependencyTok);
+    while (DependencyTok.isNot(tok::eod)) {
+      Message += getSpelling(DependencyTok) + " ";
+      Lex(DependencyTok);
+    }
+
+    // Remove the trailing ' ' if present.
+    if (!Message.empty())
+      Message.erase(Message.end()-1);
+    Diag(FilenameTok, diag::pp_out_of_date_dependency) << Message;
+  }
+}
+
+/// HandlePragmaComment - Handle the microsoft #pragma comment extension.  The
+/// syntax is:
+///   #pragma comment(linker, "foo")
+/// 'linker' is one of five identifiers: compiler, exestr, lib, linker, user.
+/// "foo" is a string, which is fully macro expanded, and permits string
+/// concatenation, embedded escape characters etc.  See MSDN for more details.
+void Preprocessor::HandlePragmaComment(Token &Tok) {
+  SourceLocation CommentLoc = Tok.getLocation();
+  Lex(Tok);
+  if (Tok.isNot(tok::l_paren)) {
+    Diag(CommentLoc, diag::err_pragma_comment_malformed);
+    return;
+  }
+
+  // Read the identifier.
+  Lex(Tok);
+  if (Tok.isNot(tok::identifier)) {
+    Diag(CommentLoc, diag::err_pragma_comment_malformed);
+    return;
+  }
+
+  // Verify that this is one of the 5 whitelisted options.
+  // FIXME: warn that 'exestr' is deprecated.
+  const IdentifierInfo *II = Tok.getIdentifierInfo();
+  if (!II->isStr("compiler") && !II->isStr("exestr") && !II->isStr("lib") &&
+      !II->isStr("linker") && !II->isStr("user")) {
+    Diag(Tok.getLocation(), diag::err_pragma_comment_unknown_kind);
+    return;
+  }
+
+  // Read the optional string if present.
+  Lex(Tok);
+  std::string ArgumentString;
+  if (Tok.is(tok::comma)) {
+    Lex(Tok); // eat the comma.
+
+    // We need at least one string.
+    if (Tok.isNot(tok::string_literal)) {
+      Diag(Tok.getLocation(), diag::err_pragma_comment_malformed);
+      return;
+    }
+
+    // String concatenation allows multiple strings, which can even come from
+    // macro expansion.
+    // "foo " "bar" "Baz"
+    SmallVector<Token, 4> StrToks;
+    while (Tok.is(tok::string_literal)) {
+      if (Tok.hasUDSuffix())
+        Diag(Tok, diag::err_invalid_string_udl);
+      StrToks.push_back(Tok);
+      Lex(Tok);
+    }
+
+    // Concatenate and parse the strings.
+    StringLiteralParser Literal(&StrToks[0], StrToks.size(), *this);
+    assert(Literal.isAscii() && "Didn't allow wide strings in");
+    if (Literal.hadError)
+      return;
+    if (Literal.Pascal) {
+      Diag(StrToks[0].getLocation(), diag::err_pragma_comment_malformed);
+      return;
+    }
+
+    ArgumentString = Literal.GetString();
+  }
+
+  // FIXME: If the kind is "compiler" warn if the string is present (it is
+  // ignored).
+  // FIXME: 'lib' requires a comment string.
+  // FIXME: 'linker' requires a comment string, and has a specific list of
+  // things that are allowable.
+
+  if (Tok.isNot(tok::r_paren)) {
+    Diag(Tok.getLocation(), diag::err_pragma_comment_malformed);
+    return;
+  }
+  Lex(Tok);  // eat the r_paren.
+
+  if (Tok.isNot(tok::eod)) {
+    Diag(Tok.getLocation(), diag::err_pragma_comment_malformed);
+    return;
+  }
+
+  // If the pragma is lexically sound, notify any interested PPCallbacks.
+  if (Callbacks)
+    Callbacks->PragmaComment(CommentLoc, II, ArgumentString);
+}
+
+/// HandlePragmaMessage - Handle the microsoft and gcc #pragma message
+/// extension.  The syntax is:
+///   #pragma message(string)
+/// OR, in GCC mode:
+///   #pragma message string
+/// string is a string, which is fully macro expanded, and permits string
+/// concatenation, embedded escape characters, etc... See MSDN for more details.
+void Preprocessor::HandlePragmaMessage(Token &Tok) {
+  SourceLocation MessageLoc = Tok.getLocation();
+  Lex(Tok);
+  bool ExpectClosingParen = false;
+  switch (Tok.getKind()) {
+  case tok::l_paren:
+    // We have a MSVC style pragma message.
+    ExpectClosingParen = true;
+    // Read the string.
+    Lex(Tok);
+    break;
+  case tok::string_literal:
+    // We have a GCC style pragma message, and we just read the string.
+    break;
+  default:
+    Diag(MessageLoc, diag::err_pragma_message_malformed);
+    return;
+  }
+
+  // We need at least one string.
+  if (Tok.isNot(tok::string_literal)) {
+    Diag(Tok.getLocation(), diag::err_pragma_message_malformed);
+    return;
+  }
+
+  // String concatenation allows multiple strings, which can even come from
+  // macro expansion.
+  // "foo " "bar" "Baz"
+  SmallVector<Token, 4> StrToks;
+  while (Tok.is(tok::string_literal)) {
+    if (Tok.hasUDSuffix())
+      Diag(Tok, diag::err_invalid_string_udl);
+    StrToks.push_back(Tok);
+    Lex(Tok);
+  }
+
+  // Concatenate and parse the strings.
+  StringLiteralParser Literal(&StrToks[0], StrToks.size(), *this);
+  assert(Literal.isAscii() && "Didn't allow wide strings in");
+  if (Literal.hadError)
+    return;
+  if (Literal.Pascal) {
+    Diag(StrToks[0].getLocation(), diag::err_pragma_message_malformed);
+    return;
+  }
+
+  StringRef MessageString(Literal.GetString());
+
+  if (ExpectClosingParen) {
+    if (Tok.isNot(tok::r_paren)) {
+      Diag(Tok.getLocation(), diag::err_pragma_message_malformed);
+      return;
+    }
+    Lex(Tok);  // eat the r_paren.
+  }
+
+  if (Tok.isNot(tok::eod)) {
+    Diag(Tok.getLocation(), diag::err_pragma_message_malformed);
+    return;
+  }
+
+  // Output the message.
+  Diag(MessageLoc, diag::warn_pragma_message) << MessageString;
+
+  // If the pragma is lexically sound, notify any interested PPCallbacks.
+  if (Callbacks)
+    Callbacks->PragmaMessage(MessageLoc, MessageString);
+}
+
+/// ParsePragmaPushOrPopMacro - Handle parsing of pragma push_macro/pop_macro.  
+/// Return the IdentifierInfo* associated with the macro to push or pop.
+IdentifierInfo *Preprocessor::ParsePragmaPushOrPopMacro(Token &Tok) {
+  // Remember the pragma token location.
+  Token PragmaTok = Tok;
+
+  // Read the '('.
+  Lex(Tok);
+  if (Tok.isNot(tok::l_paren)) {
+    Diag(PragmaTok.getLocation(), diag::err_pragma_push_pop_macro_malformed)
+      << getSpelling(PragmaTok);
+    return 0;
+  }
+
+  // Read the macro name string.
+  Lex(Tok);
+  if (Tok.isNot(tok::string_literal)) {
+    Diag(PragmaTok.getLocation(), diag::err_pragma_push_pop_macro_malformed)
+      << getSpelling(PragmaTok);
+    return 0;
+  }
+
+  if (Tok.hasUDSuffix()) {
+    Diag(Tok, diag::err_invalid_string_udl);
+    return 0;
+  }
+
+  // Remember the macro string.
+  std::string StrVal = getSpelling(Tok);
+
+  // Read the ')'.
+  Lex(Tok);
+  if (Tok.isNot(tok::r_paren)) {
+    Diag(PragmaTok.getLocation(), diag::err_pragma_push_pop_macro_malformed)
+      << getSpelling(PragmaTok);
+    return 0;
+  }
+
+  assert(StrVal[0] == '"' && StrVal[StrVal.size()-1] == '"' &&
+         "Invalid string token!");
+
+  // Create a Token from the string.
+  Token MacroTok;
+  MacroTok.startToken();
+  MacroTok.setKind(tok::raw_identifier);
+  CreateString(&StrVal[1], StrVal.size() - 2, MacroTok);
+
+  // Get the IdentifierInfo of MacroToPushTok.
+  return LookUpIdentifierInfo(MacroTok);
+}
+
+/// HandlePragmaPushMacro - Handle #pragma push_macro.  
+/// The syntax is:
+///   #pragma push_macro("macro")
+void Preprocessor::HandlePragmaPushMacro(Token &PushMacroTok) {
+  // Parse the pragma directive and get the macro IdentifierInfo*.
+  IdentifierInfo *IdentInfo = ParsePragmaPushOrPopMacro(PushMacroTok);
+  if (!IdentInfo) return;
+
+  // Get the MacroInfo associated with IdentInfo.
+  MacroInfo *MI = getMacroInfo(IdentInfo);
+ 
+  MacroInfo *MacroCopyToPush = 0;
+  if (MI) {
+    // Make a clone of MI.
+    MacroCopyToPush = CloneMacroInfo(*MI);
+    
+    // Allow the original MacroInfo to be redefined later.
+    MI->setIsAllowRedefinitionsWithoutWarning(true);
+  }
+
+  // Push the cloned MacroInfo so we can retrieve it later.
+  PragmaPushMacroInfo[IdentInfo].push_back(MacroCopyToPush);
+}
+
+/// HandlePragmaPopMacro - Handle #pragma pop_macro.  
+/// The syntax is:
+///   #pragma pop_macro("macro")
+void Preprocessor::HandlePragmaPopMacro(Token &PopMacroTok) {
+  SourceLocation MessageLoc = PopMacroTok.getLocation();
+
+  // Parse the pragma directive and get the macro IdentifierInfo*.
+  IdentifierInfo *IdentInfo = ParsePragmaPushOrPopMacro(PopMacroTok);
+  if (!IdentInfo) return;
+
+  // Find the vector<MacroInfo*> associated with the macro.
+  llvm::DenseMap<IdentifierInfo*, std::vector<MacroInfo*> >::iterator iter =
+    PragmaPushMacroInfo.find(IdentInfo);
+  if (iter != PragmaPushMacroInfo.end()) {
+    // Release the MacroInfo currently associated with IdentInfo.
+    MacroInfo *CurrentMI = getMacroInfo(IdentInfo);
+    if (CurrentMI) {
+      if (CurrentMI->isWarnIfUnused())
+        WarnUnusedMacroLocs.erase(CurrentMI->getDefinitionLoc());
+      ReleaseMacroInfo(CurrentMI);
+    }
+
+    // Get the MacroInfo we want to reinstall.
+    MacroInfo *MacroToReInstall = iter->second.back();
+
+    // Reinstall the previously pushed macro.
+    setMacroInfo(IdentInfo, MacroToReInstall);
+
+    // Pop PragmaPushMacroInfo stack.
+    iter->second.pop_back();
+    if (iter->second.size() == 0)
+      PragmaPushMacroInfo.erase(iter);
+  } else {
+    Diag(MessageLoc, diag::warn_pragma_pop_macro_no_push)
+      << IdentInfo->getName();
+  }
+}
+
+void Preprocessor::HandlePragmaIncludeAlias(Token &Tok) {
+  // We will either get a quoted filename or a bracketed filename, and we 
+  // have to track which we got.  The first filename is the source name,
+  // and the second name is the mapped filename.  If the first is quoted,
+  // the second must be as well (cannot mix and match quotes and brackets).
+
+  // Get the open paren
+  Lex(Tok);
+  if (Tok.isNot(tok::l_paren)) {
+    Diag(Tok, diag::warn_pragma_include_alias_expected) << "(";
+    return;
+  }
+
+  // We expect either a quoted string literal, or a bracketed name
+  Token SourceFilenameTok;
+  CurPPLexer->LexIncludeFilename(SourceFilenameTok);
+  if (SourceFilenameTok.is(tok::eod)) {
+    // The diagnostic has already been handled
+    return;
+  }
+
+  StringRef SourceFileName;
+  SmallString<128> FileNameBuffer;
+  if (SourceFilenameTok.is(tok::string_literal) || 
+      SourceFilenameTok.is(tok::angle_string_literal)) {
+    SourceFileName = getSpelling(SourceFilenameTok, FileNameBuffer);
+  } else if (SourceFilenameTok.is(tok::less)) {
+    // This could be a path instead of just a name
+    FileNameBuffer.push_back('<');
+    SourceLocation End;
+    if (ConcatenateIncludeName(FileNameBuffer, End))
+      return; // Diagnostic already emitted
+    SourceFileName = FileNameBuffer.str();
+  } else {
+    Diag(Tok, diag::warn_pragma_include_alias_expected_filename);
+    return;
+  }
+  FileNameBuffer.clear();
+
+  // Now we expect a comma, followed by another include name
+  Lex(Tok);
+  if (Tok.isNot(tok::comma)) {
+    Diag(Tok, diag::warn_pragma_include_alias_expected) << ",";
+    return;
+  }
+
+  Token ReplaceFilenameTok;
+  CurPPLexer->LexIncludeFilename(ReplaceFilenameTok);
+  if (ReplaceFilenameTok.is(tok::eod)) {
+    // The diagnostic has already been handled
+    return;
+  }
+
+  StringRef ReplaceFileName;
+  if (ReplaceFilenameTok.is(tok::string_literal) || 
+      ReplaceFilenameTok.is(tok::angle_string_literal)) {
+    ReplaceFileName = getSpelling(ReplaceFilenameTok, FileNameBuffer);
+  } else if (ReplaceFilenameTok.is(tok::less)) {
+    // This could be a path instead of just a name
+    FileNameBuffer.push_back('<');
+    SourceLocation End;
+    if (ConcatenateIncludeName(FileNameBuffer, End))
+      return; // Diagnostic already emitted
+    ReplaceFileName = FileNameBuffer.str();
+  } else {
+    Diag(Tok, diag::warn_pragma_include_alias_expected_filename);
+    return;
+  }
+
+  // Finally, we expect the closing paren
+  Lex(Tok);
+  if (Tok.isNot(tok::r_paren)) {
+    Diag(Tok, diag::warn_pragma_include_alias_expected) << ")";
+    return;
+  }
+
+  // Now that we have the source and target filenames, we need to make sure
+  // they're both of the same type (angled vs non-angled)
+  StringRef OriginalSource = SourceFileName;
+
+  bool SourceIsAngled = 
+    GetIncludeFilenameSpelling(SourceFilenameTok.getLocation(), 
+                                SourceFileName);
+  bool ReplaceIsAngled =
+    GetIncludeFilenameSpelling(ReplaceFilenameTok.getLocation(),
+                                ReplaceFileName);
+  if (!SourceFileName.empty() && !ReplaceFileName.empty() &&
+      (SourceIsAngled != ReplaceIsAngled)) {
+    unsigned int DiagID;
+    if (SourceIsAngled)
+      DiagID = diag::warn_pragma_include_alias_mismatch_angle;
+    else
+      DiagID = diag::warn_pragma_include_alias_mismatch_quote;
+
+    Diag(SourceFilenameTok.getLocation(), DiagID)
+      << SourceFileName 
+      << ReplaceFileName;
+
+    return;
+  }
+
+  // Now we can let the include handler know about this mapping
+  getHeaderSearchInfo().AddIncludeAlias(OriginalSource, ReplaceFileName);
+}
+
+/// AddPragmaHandler - Add the specified pragma handler to the preprocessor.
+/// If 'Namespace' is non-null, then it is a token required to exist on the
+/// pragma line before the pragma string starts, e.g. "STDC" or "GCC".
+void Preprocessor::AddPragmaHandler(StringRef Namespace,
+                                    PragmaHandler *Handler) {
+  PragmaNamespace *InsertNS = PragmaHandlers;
+
+  // If this is specified to be in a namespace, step down into it.
+  if (!Namespace.empty()) {
+    // If there is already a pragma handler with the name of this namespace,
+    // we either have an error (directive with the same name as a namespace) or
+    // we already have the namespace to insert into.
+    if (PragmaHandler *Existing = PragmaHandlers->FindHandler(Namespace)) {
+      InsertNS = Existing->getIfNamespace();
+      assert(InsertNS != 0 && "Cannot have a pragma namespace and pragma"
+             " handler with the same name!");
+    } else {
+      // Otherwise, this namespace doesn't exist yet, create and insert the
+      // handler for it.
+      InsertNS = new PragmaNamespace(Namespace);
+      PragmaHandlers->AddPragma(InsertNS);
+    }
+  }
+
+  // Check to make sure we don't already have a pragma for this identifier.
+  assert(!InsertNS->FindHandler(Handler->getName()) &&
+         "Pragma handler already exists for this identifier!");
+  InsertNS->AddPragma(Handler);
+}
+
+/// RemovePragmaHandler - Remove the specific pragma handler from the
+/// preprocessor. If \arg Namespace is non-null, then it should be the
+/// namespace that \arg Handler was added to. It is an error to remove
+/// a handler that has not been registered.
+void Preprocessor::RemovePragmaHandler(StringRef Namespace,
+                                       PragmaHandler *Handler) {
+  PragmaNamespace *NS = PragmaHandlers;
+
+  // If this is specified to be in a namespace, step down into it.
+  if (!Namespace.empty()) {
+    PragmaHandler *Existing = PragmaHandlers->FindHandler(Namespace);
+    assert(Existing && "Namespace containing handler does not exist!");
+
+    NS = Existing->getIfNamespace();
+    assert(NS && "Invalid namespace, registered as a regular pragma handler!");
+  }
+
+  NS->RemovePragmaHandler(Handler);
+
+  // If this is a non-default namespace and it is now empty, remove
+  // it.
+  if (NS != PragmaHandlers && NS->IsEmpty()) {
+    PragmaHandlers->RemovePragmaHandler(NS);
+    delete NS;
+  }
+}
+
+bool Preprocessor::LexOnOffSwitch(tok::OnOffSwitch &Result) {
+  Token Tok;
+  LexUnexpandedToken(Tok);
+
+  if (Tok.isNot(tok::identifier)) {
+    Diag(Tok, diag::ext_on_off_switch_syntax);
+    return true;
+  }
+  IdentifierInfo *II = Tok.getIdentifierInfo();
+  if (II->isStr("ON"))
+    Result = tok::OOS_ON;
+  else if (II->isStr("OFF"))
+    Result = tok::OOS_OFF;
+  else if (II->isStr("DEFAULT"))
+    Result = tok::OOS_DEFAULT;
+  else {
+    Diag(Tok, diag::ext_on_off_switch_syntax);
+    return true;
+  }
+
+  // Verify that this is followed by EOD.
+  LexUnexpandedToken(Tok);
+  if (Tok.isNot(tok::eod))
+    Diag(Tok, diag::ext_pragma_syntax_eod);
+  return false;
+}
+
+namespace {
+/// PragmaOnceHandler - "#pragma once" marks the file as atomically included.
+struct PragmaOnceHandler : public PragmaHandler {
+  PragmaOnceHandler() : PragmaHandler("once") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &OnceTok) {
+    PP.CheckEndOfDirective("pragma once");
+    PP.HandlePragmaOnce(OnceTok);
+  }
+};
+
+/// PragmaMarkHandler - "#pragma mark ..." is ignored by the compiler, and the
+/// rest of the line is not lexed.
+struct PragmaMarkHandler : public PragmaHandler {
+  PragmaMarkHandler() : PragmaHandler("mark") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &MarkTok) {
+    PP.HandlePragmaMark();
+  }
+};
+
+/// PragmaPoisonHandler - "#pragma poison x" marks x as not usable.
+struct PragmaPoisonHandler : public PragmaHandler {
+  PragmaPoisonHandler() : PragmaHandler("poison") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &PoisonTok) {
+    PP.HandlePragmaPoison(PoisonTok);
+  }
+};
+
+/// PragmaSystemHeaderHandler - "#pragma system_header" marks the current file
+/// as a system header, which silences warnings in it.
+struct PragmaSystemHeaderHandler : public PragmaHandler {
+  PragmaSystemHeaderHandler() : PragmaHandler("system_header") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &SHToken) {
+    PP.HandlePragmaSystemHeader(SHToken);
+    PP.CheckEndOfDirective("pragma");
+  }
+};
+struct PragmaDependencyHandler : public PragmaHandler {
+  PragmaDependencyHandler() : PragmaHandler("dependency") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &DepToken) {
+    PP.HandlePragmaDependency(DepToken);
+  }
+};
+
+struct PragmaDebugHandler : public PragmaHandler {
+  PragmaDebugHandler() : PragmaHandler("__debug") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &DepToken) {
+    Token Tok;
+    PP.LexUnexpandedToken(Tok);
+    if (Tok.isNot(tok::identifier)) {
+      PP.Diag(Tok, diag::warn_pragma_diagnostic_invalid);
+      return;
+    }
+    IdentifierInfo *II = Tok.getIdentifierInfo();
+
+    if (II->isStr("assert")) {
+      llvm_unreachable("This is an assertion!");
+    } else if (II->isStr("crash")) {
+      *(volatile int*) 0x11 = 0;
+    } else if (II->isStr("llvm_fatal_error")) {
+      llvm::report_fatal_error("#pragma clang __debug llvm_fatal_error");
+    } else if (II->isStr("llvm_unreachable")) {
+      llvm_unreachable("#pragma clang __debug llvm_unreachable");
+    } else if (II->isStr("overflow_stack")) {
+      DebugOverflowStack();
+    } else if (II->isStr("handle_crash")) {
+      llvm::CrashRecoveryContext *CRC =llvm::CrashRecoveryContext::GetCurrent();
+      if (CRC)
+        CRC->HandleCrash();
+    } else {
+      PP.Diag(Tok, diag::warn_pragma_debug_unexpected_command)
+        << II->getName();
+    }
+  }
+
+// Disable MSVC warning about runtime stack overflow.
+#ifdef _MSC_VER
+    #pragma warning(disable : 4717)
+#endif
+  void DebugOverflowStack() {
+    DebugOverflowStack();
+  }
+#ifdef _MSC_VER
+    #pragma warning(default : 4717)
+#endif
+
+};
+
+/// PragmaDiagnosticHandler - e.g. '#pragma GCC diagnostic ignored "-Wformat"'
+struct PragmaDiagnosticHandler : public PragmaHandler {
+private:
+  const char *Namespace;
+public:
+  explicit PragmaDiagnosticHandler(const char *NS) :
+    PragmaHandler("diagnostic"), Namespace(NS) {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &DiagToken) {
+    SourceLocation DiagLoc = DiagToken.getLocation();
+    Token Tok;
+    PP.LexUnexpandedToken(Tok);
+    if (Tok.isNot(tok::identifier)) {
+      PP.Diag(Tok, diag::warn_pragma_diagnostic_invalid);
+      return;
+    }
+    IdentifierInfo *II = Tok.getIdentifierInfo();
+    PPCallbacks *Callbacks = PP.getPPCallbacks();
+
+    diag::Mapping Map;
+    if (II->isStr("warning"))
+      Map = diag::MAP_WARNING;
+    else if (II->isStr("error"))
+      Map = diag::MAP_ERROR;
+    else if (II->isStr("ignored"))
+      Map = diag::MAP_IGNORE;
+    else if (II->isStr("fatal"))
+      Map = diag::MAP_FATAL;
+    else if (II->isStr("pop")) {
+      if (!PP.getDiagnostics().popMappings(DiagLoc))
+        PP.Diag(Tok, diag::warn_pragma_diagnostic_cannot_pop);
+      else if (Callbacks)
+        Callbacks->PragmaDiagnosticPop(DiagLoc, Namespace);
+      return;
+    } else if (II->isStr("push")) {
+      PP.getDiagnostics().pushMappings(DiagLoc);
+      if (Callbacks)
+        Callbacks->PragmaDiagnosticPush(DiagLoc, Namespace);
+      return;
+    } else {
+      PP.Diag(Tok, diag::warn_pragma_diagnostic_invalid);
+      return;
+    }
+
+    PP.LexUnexpandedToken(Tok);
+
+    // We need at least one string.
+    if (Tok.isNot(tok::string_literal)) {
+      PP.Diag(Tok.getLocation(), diag::warn_pragma_diagnostic_invalid_token);
+      return;
+    }
+
+    // String concatenation allows multiple strings, which can even come from
+    // macro expansion.
+    // "foo " "bar" "Baz"
+    SmallVector<Token, 4> StrToks;
+    while (Tok.is(tok::string_literal)) {
+      StrToks.push_back(Tok);
+      PP.LexUnexpandedToken(Tok);
+    }
+
+    if (Tok.isNot(tok::eod)) {
+      PP.Diag(Tok.getLocation(), diag::warn_pragma_diagnostic_invalid_token);
+      return;
+    }
+
+    // Concatenate and parse the strings.
+    StringLiteralParser Literal(&StrToks[0], StrToks.size(), PP);
+    assert(Literal.isAscii() && "Didn't allow wide strings in");
+    if (Literal.hadError)
+      return;
+    if (Literal.Pascal) {
+      PP.Diag(Tok, diag::warn_pragma_diagnostic_invalid);
+      return;
+    }
+
+    StringRef WarningName(Literal.GetString());
+
+    if (WarningName.size() < 3 || WarningName[0] != '-' ||
+        WarningName[1] != 'W') {
+      PP.Diag(StrToks[0].getLocation(),
+              diag::warn_pragma_diagnostic_invalid_option);
+      return;
+    }
+
+    if (PP.getDiagnostics().setDiagnosticGroupMapping(WarningName.substr(2),
+                                                      Map, DiagLoc))
+      PP.Diag(StrToks[0].getLocation(),
+              diag::warn_pragma_diagnostic_unknown_warning) << WarningName;
+    else if (Callbacks)
+      Callbacks->PragmaDiagnostic(DiagLoc, Namespace, Map, WarningName);
+  }
+};
+
+/// PragmaCommentHandler - "#pragma comment ...".
+struct PragmaCommentHandler : public PragmaHandler {
+  PragmaCommentHandler() : PragmaHandler("comment") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &CommentTok) {
+    PP.HandlePragmaComment(CommentTok);
+  }
+};
+
+/// PragmaIncludeAliasHandler - "#pragma include_alias("...")".
+struct PragmaIncludeAliasHandler : public PragmaHandler {
+  PragmaIncludeAliasHandler() : PragmaHandler("include_alias") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &IncludeAliasTok) {
+      PP.HandlePragmaIncludeAlias(IncludeAliasTok);
+  }
+};
+
+/// PragmaMessageHandler - "#pragma message("...")".
+struct PragmaMessageHandler : public PragmaHandler {
+  PragmaMessageHandler() : PragmaHandler("message") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &CommentTok) {
+    PP.HandlePragmaMessage(CommentTok);
+  }
+};
+
+/// PragmaPushMacroHandler - "#pragma push_macro" saves the value of the
+/// macro on the top of the stack.
+struct PragmaPushMacroHandler : public PragmaHandler {
+  PragmaPushMacroHandler() : PragmaHandler("push_macro") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &PushMacroTok) {
+    PP.HandlePragmaPushMacro(PushMacroTok);
+  }
+};
+
+
+/// PragmaPopMacroHandler - "#pragma pop_macro" sets the value of the
+/// macro to the value on the top of the stack.
+struct PragmaPopMacroHandler : public PragmaHandler {
+  PragmaPopMacroHandler() : PragmaHandler("pop_macro") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &PopMacroTok) {
+    PP.HandlePragmaPopMacro(PopMacroTok);
+  }
+};
+
+// Pragma STDC implementations.
+
+/// PragmaSTDC_FENV_ACCESSHandler - "#pragma STDC FENV_ACCESS ...".
+struct PragmaSTDC_FENV_ACCESSHandler : public PragmaHandler {
+  PragmaSTDC_FENV_ACCESSHandler() : PragmaHandler("FENV_ACCESS") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &Tok) {
+    tok::OnOffSwitch OOS;
+    if (PP.LexOnOffSwitch(OOS))
+     return;
+    if (OOS == tok::OOS_ON)
+      PP.Diag(Tok, diag::warn_stdc_fenv_access_not_supported);
+  }
+};
+
+/// PragmaSTDC_CX_LIMITED_RANGEHandler - "#pragma STDC CX_LIMITED_RANGE ...".
+struct PragmaSTDC_CX_LIMITED_RANGEHandler : public PragmaHandler {
+  PragmaSTDC_CX_LIMITED_RANGEHandler()
+    : PragmaHandler("CX_LIMITED_RANGE") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &Tok) {
+    tok::OnOffSwitch OOS;
+    PP.LexOnOffSwitch(OOS);
+  }
+};
+
+/// PragmaSTDC_UnknownHandler - "#pragma STDC ...".
+struct PragmaSTDC_UnknownHandler : public PragmaHandler {
+  PragmaSTDC_UnknownHandler() {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &UnknownTok) {
+    // C99 6.10.6p2, unknown forms are not allowed.
+    PP.Diag(UnknownTok, diag::ext_stdc_pragma_ignored);
+  }
+};
+
+/// PragmaARCCFCodeAuditedHandler - 
+///   #pragma clang arc_cf_code_audited begin/end
+struct PragmaARCCFCodeAuditedHandler : public PragmaHandler {
+  PragmaARCCFCodeAuditedHandler() : PragmaHandler("arc_cf_code_audited") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &NameTok) {
+    SourceLocation Loc = NameTok.getLocation();
+    bool IsBegin;
+
+    Token Tok;
+
+    // Lex the 'begin' or 'end'.
+    PP.LexUnexpandedToken(Tok);
+    const IdentifierInfo *BeginEnd = Tok.getIdentifierInfo();
+    if (BeginEnd && BeginEnd->isStr("begin")) {
+      IsBegin = true;
+    } else if (BeginEnd && BeginEnd->isStr("end")) {
+      IsBegin = false;
+    } else {
+      PP.Diag(Tok.getLocation(), diag::err_pp_arc_cf_code_audited_syntax);
+      return;
+    }
+
+    // Verify that this is followed by EOD.
+    PP.LexUnexpandedToken(Tok);
+    if (Tok.isNot(tok::eod))
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma";
+
+    // The start location of the active audit.
+    SourceLocation BeginLoc = PP.getPragmaARCCFCodeAuditedLoc();
+
+    // The start location we want after processing this.
+    SourceLocation NewLoc;
+
+    if (IsBegin) {
+      // Complain about attempts to re-enter an audit.
+      if (BeginLoc.isValid()) {
+        PP.Diag(Loc, diag::err_pp_double_begin_of_arc_cf_code_audited);
+        PP.Diag(BeginLoc, diag::note_pragma_entered_here);
+      }
+      NewLoc = Loc;
+    } else {
+      // Complain about attempts to leave an audit that doesn't exist.
+      if (!BeginLoc.isValid()) {
+        PP.Diag(Loc, diag::err_pp_unmatched_end_of_arc_cf_code_audited);
+        return;
+      }
+      NewLoc = SourceLocation();
+    }
+
+    PP.setPragmaARCCFCodeAuditedLoc(NewLoc);
+  }
+};
+
+}  // end anonymous namespace
+
+
+/// RegisterBuiltinPragmas - Install the standard preprocessor pragmas:
+/// #pragma GCC poison/system_header/dependency and #pragma once.
+void Preprocessor::RegisterBuiltinPragmas() {
+  AddPragmaHandler(new PragmaOnceHandler());
+  AddPragmaHandler(new PragmaMarkHandler());
+  AddPragmaHandler(new PragmaPushMacroHandler());
+  AddPragmaHandler(new PragmaPopMacroHandler());
+  AddPragmaHandler(new PragmaMessageHandler());
+
+  // #pragma GCC ...
+  AddPragmaHandler("GCC", new PragmaPoisonHandler());
+  AddPragmaHandler("GCC", new PragmaSystemHeaderHandler());
+  AddPragmaHandler("GCC", new PragmaDependencyHandler());
+  AddPragmaHandler("GCC", new PragmaDiagnosticHandler("GCC"));
+  // #pragma clang ...
+  AddPragmaHandler("clang", new PragmaPoisonHandler());
+  AddPragmaHandler("clang", new PragmaSystemHeaderHandler());
+  AddPragmaHandler("clang", new PragmaDebugHandler());
+  AddPragmaHandler("clang", new PragmaDependencyHandler());
+  AddPragmaHandler("clang", new PragmaDiagnosticHandler("clang"));
+  AddPragmaHandler("clang", new PragmaARCCFCodeAuditedHandler());
+
+  AddPragmaHandler("STDC", new PragmaSTDC_FENV_ACCESSHandler());
+  AddPragmaHandler("STDC", new PragmaSTDC_CX_LIMITED_RANGEHandler());
+  AddPragmaHandler("STDC", new PragmaSTDC_UnknownHandler());
+
+  // MS extensions.
+  if (LangOpts.MicrosoftExt) {
+    AddPragmaHandler(new PragmaCommentHandler());
+    AddPragmaHandler(new PragmaIncludeAliasHandler());
+  }
+}