Check in LLVM r95781.
diff --git a/lib/Lex/PPDirectives.cpp b/lib/Lex/PPDirectives.cpp
new file mode 100644
index 0000000..b0e784b
--- /dev/null
+++ b/lib/Lex/PPDirectives.cpp
@@ -0,0 +1,1654 @@
+//===--- PPDirectives.cpp - Directive Handling for Preprocessor -----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements # directive processing for the Preprocessor.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Lex/LiteralSupport.h"
+#include "clang/Lex/HeaderSearch.h"
+#include "clang/Lex/MacroInfo.h"
+#include "clang/Lex/LexDiagnostic.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/SourceManager.h"
+#include "llvm/ADT/APInt.h"
+using namespace clang;
+
+//===----------------------------------------------------------------------===//
+// Utility Methods for Preprocessor Directive Handling.
+//===----------------------------------------------------------------------===//
+
+MacroInfo *Preprocessor::AllocateMacroInfo(SourceLocation L) {
+  MacroInfo *MI;
+
+  if (!MICache.empty()) {
+    MI = MICache.back();
+    MICache.pop_back();
+  } else
+    MI = (MacroInfo*) BP.Allocate<MacroInfo>();
+  new (MI) MacroInfo(L);
+  return MI;
+}
+
+/// ReleaseMacroInfo - Release the specified MacroInfo.  This memory will
+///  be reused for allocating new MacroInfo objects.
+void Preprocessor::ReleaseMacroInfo(MacroInfo* MI) {
+  MICache.push_back(MI);
+  MI->FreeArgumentList(BP);
+}
+
+
+/// DiscardUntilEndOfDirective - Read and discard all tokens remaining on the
+/// current line until the tok::eom token is found.
+void Preprocessor::DiscardUntilEndOfDirective() {
+  Token Tmp;
+  do {
+    LexUnexpandedToken(Tmp);
+  } while (Tmp.isNot(tok::eom));
+}
+
+/// ReadMacroName - Lex and validate a macro name, which occurs after a
+/// #define or #undef.  This sets the token kind to eom and discards the rest
+/// of the macro line if the macro name is invalid.  isDefineUndef is 1 if
+/// this is due to a a #define, 2 if #undef directive, 0 if it is something
+/// else (e.g. #ifdef).
+void Preprocessor::ReadMacroName(Token &MacroNameTok, char isDefineUndef) {
+  // Read the token, don't allow macro expansion on it.
+  LexUnexpandedToken(MacroNameTok);
+
+  // Missing macro name?
+  if (MacroNameTok.is(tok::eom)) {
+    Diag(MacroNameTok, diag::err_pp_missing_macro_name);
+    return;
+  }
+
+  IdentifierInfo *II = MacroNameTok.getIdentifierInfo();
+  if (II == 0) {
+    std::string Spelling = getSpelling(MacroNameTok);
+    const IdentifierInfo &Info = Identifiers.get(Spelling);
+    if (Info.isCPlusPlusOperatorKeyword())
+      // C++ 2.5p2: Alternative tokens behave the same as its primary token
+      // except for their spellings.
+      Diag(MacroNameTok, diag::err_pp_operator_used_as_macro_name) << Spelling;
+    else
+      Diag(MacroNameTok, diag::err_pp_macro_not_identifier);
+    // Fall through on error.
+  } else if (isDefineUndef && II->getPPKeywordID() == tok::pp_defined) {
+    // Error if defining "defined": C99 6.10.8.4.
+    Diag(MacroNameTok, diag::err_defined_macro_name);
+  } else if (isDefineUndef && II->hasMacroDefinition() &&
+             getMacroInfo(II)->isBuiltinMacro()) {
+    // Error if defining "__LINE__" and other builtins: C99 6.10.8.4.
+    if (isDefineUndef == 1)
+      Diag(MacroNameTok, diag::pp_redef_builtin_macro);
+    else
+      Diag(MacroNameTok, diag::pp_undef_builtin_macro);
+  } else {
+    // Okay, we got a good identifier node.  Return it.
+    return;
+  }
+
+  // Invalid macro name, read and discard the rest of the line.  Then set the
+  // token kind to tok::eom.
+  MacroNameTok.setKind(tok::eom);
+  return DiscardUntilEndOfDirective();
+}
+
+/// CheckEndOfDirective - Ensure that the next token is a tok::eom token.  If
+/// not, emit a diagnostic and consume up until the eom.  If EnableMacros is
+/// true, then we consider macros that expand to zero tokens as being ok.
+void Preprocessor::CheckEndOfDirective(const char *DirType, bool EnableMacros) {
+  Token Tmp;
+  // Lex unexpanded tokens for most directives: macros might expand to zero
+  // tokens, causing us to miss diagnosing invalid lines.  Some directives (like
+  // #line) allow empty macros.
+  if (EnableMacros)
+    Lex(Tmp);
+  else
+    LexUnexpandedToken(Tmp);
+
+  // There should be no tokens after the directive, but we allow them as an
+  // extension.
+  while (Tmp.is(tok::comment))  // Skip comments in -C mode.
+    LexUnexpandedToken(Tmp);
+
+  if (Tmp.isNot(tok::eom)) {
+    // Add a fixit in GNU/C99/C++ mode.  Don't offer a fixit for strict-C89,
+    // because it is more trouble than it is worth to insert /**/ and check that
+    // there is no /**/ in the range also.
+    CodeModificationHint FixItHint;
+    if (Features.GNUMode || Features.C99 || Features.CPlusPlus)
+      FixItHint = CodeModificationHint::CreateInsertion(Tmp.getLocation(),"//");
+    Diag(Tmp, diag::ext_pp_extra_tokens_at_eol) << DirType << FixItHint;
+    DiscardUntilEndOfDirective();
+  }
+}
+
+
+
+/// SkipExcludedConditionalBlock - We just read a #if or related directive and
+/// decided that the subsequent tokens are in the #if'd out portion of the
+/// file.  Lex the rest of the file, until we see an #endif.  If
+/// FoundNonSkipPortion is true, then we have already emitted code for part of
+/// this #if directive, so #else/#elif blocks should never be entered. If ElseOk
+/// is true, then #else directives are ok, if not, then we have already seen one
+/// so a #else directive is a duplicate.  When this returns, the caller can lex
+/// the first valid token.
+void Preprocessor::SkipExcludedConditionalBlock(SourceLocation IfTokenLoc,
+                                                bool FoundNonSkipPortion,
+                                                bool FoundElse) {
+  ++NumSkipped;
+  assert(CurTokenLexer == 0 && CurPPLexer && "Lexing a macro, not a file?");
+
+  CurPPLexer->pushConditionalLevel(IfTokenLoc, /*isSkipping*/false,
+                                 FoundNonSkipPortion, FoundElse);
+
+  if (CurPTHLexer) {
+    PTHSkipExcludedConditionalBlock();
+    return;
+  }
+
+  // Enter raw mode to disable identifier lookup (and thus macro expansion),
+  // disabling warnings, etc.
+  CurPPLexer->LexingRawMode = true;
+  Token Tok;
+  while (1) {
+    CurLexer->Lex(Tok);
+
+    // If this is the end of the buffer, we have an error.
+    if (Tok.is(tok::eof)) {
+      // Emit errors for each unterminated conditional on the stack, including
+      // the current one.
+      while (!CurPPLexer->ConditionalStack.empty()) {
+        Diag(CurPPLexer->ConditionalStack.back().IfLoc,
+             diag::err_pp_unterminated_conditional);
+        CurPPLexer->ConditionalStack.pop_back();
+      }
+
+      // Just return and let the caller lex after this #include.
+      break;
+    }
+
+    // If this token is not a preprocessor directive, just skip it.
+    if (Tok.isNot(tok::hash) || !Tok.isAtStartOfLine())
+      continue;
+
+    // We just parsed a # character at the start of a line, so we're in
+    // directive mode.  Tell the lexer this so any newlines we see will be
+    // converted into an EOM token (this terminates the macro).
+    CurPPLexer->ParsingPreprocessorDirective = true;
+    if (CurLexer) CurLexer->SetCommentRetentionState(false);
+
+
+    // Read the next token, the directive flavor.
+    LexUnexpandedToken(Tok);
+
+    // If this isn't an identifier directive (e.g. is "# 1\n" or "#\n", or
+    // something bogus), skip it.
+    if (Tok.isNot(tok::identifier)) {
+      CurPPLexer->ParsingPreprocessorDirective = false;
+      // Restore comment saving mode.
+      if (CurLexer) CurLexer->SetCommentRetentionState(KeepComments);
+      continue;
+    }
+
+    // If the first letter isn't i or e, it isn't intesting to us.  We know that
+    // this is safe in the face of spelling differences, because there is no way
+    // to spell an i/e in a strange way that is another letter.  Skipping this
+    // allows us to avoid looking up the identifier info for #define/#undef and
+    // other common directives.
+    const char *RawCharData = SourceMgr.getCharacterData(Tok.getLocation());
+    char FirstChar = RawCharData[0];
+    if (FirstChar >= 'a' && FirstChar <= 'z' &&
+        FirstChar != 'i' && FirstChar != 'e') {
+      CurPPLexer->ParsingPreprocessorDirective = false;
+      // Restore comment saving mode.
+      if (CurLexer) CurLexer->SetCommentRetentionState(KeepComments);
+      continue;
+    }
+
+    // Get the identifier name without trigraphs or embedded newlines.  Note
+    // that we can't use Tok.getIdentifierInfo() because its lookup is disabled
+    // when skipping.
+    char DirectiveBuf[20];
+    llvm::StringRef Directive;
+    if (!Tok.needsCleaning() && Tok.getLength() < 20) {
+      Directive = llvm::StringRef(RawCharData, Tok.getLength());
+    } else {
+      std::string DirectiveStr = getSpelling(Tok);
+      unsigned IdLen = DirectiveStr.size();
+      if (IdLen >= 20) {
+        CurPPLexer->ParsingPreprocessorDirective = false;
+        // Restore comment saving mode.
+        if (CurLexer) CurLexer->SetCommentRetentionState(KeepComments);
+        continue;
+      }
+      memcpy(DirectiveBuf, &DirectiveStr[0], IdLen);
+      Directive = llvm::StringRef(DirectiveBuf, IdLen);
+    }
+
+    if (Directive.startswith("if")) {
+      llvm::StringRef Sub = Directive.substr(2);
+      if (Sub.empty() ||   // "if"
+          Sub == "def" ||   // "ifdef"
+          Sub == "ndef") {  // "ifndef"
+        // We know the entire #if/#ifdef/#ifndef block will be skipped, don't
+        // bother parsing the condition.
+        DiscardUntilEndOfDirective();
+        CurPPLexer->pushConditionalLevel(Tok.getLocation(), /*wasskipping*/true,
+                                       /*foundnonskip*/false,
+                                       /*fnddelse*/false);
+      }
+    } else if (Directive[0] == 'e') {
+      llvm::StringRef Sub = Directive.substr(1);
+      if (Sub == "ndif") {  // "endif"
+        CheckEndOfDirective("endif");
+        PPConditionalInfo CondInfo;
+        CondInfo.WasSkipping = true; // Silence bogus warning.
+        bool InCond = CurPPLexer->popConditionalLevel(CondInfo);
+        InCond = InCond;  // Silence warning in no-asserts mode.
+        assert(!InCond && "Can't be skipping if not in a conditional!");
+
+        // If we popped the outermost skipping block, we're done skipping!
+        if (!CondInfo.WasSkipping)
+          break;
+      } else if (Sub == "lse") { // "else".
+        // #else directive in a skipping conditional.  If not in some other
+        // skipping conditional, and if #else hasn't already been seen, enter it
+        // as a non-skipping conditional.
+        DiscardUntilEndOfDirective();  // C99 6.10p4.
+        PPConditionalInfo &CondInfo = CurPPLexer->peekConditionalLevel();
+
+        // If this is a #else with a #else before it, report the error.
+        if (CondInfo.FoundElse) Diag(Tok, diag::pp_err_else_after_else);
+
+        // Note that we've seen a #else in this conditional.
+        CondInfo.FoundElse = true;
+
+        // If the conditional is at the top level, and the #if block wasn't
+        // entered, enter the #else block now.
+        if (!CondInfo.WasSkipping && !CondInfo.FoundNonSkip) {
+          CondInfo.FoundNonSkip = true;
+          break;
+        }
+      } else if (Sub == "lif") {  // "elif".
+        PPConditionalInfo &CondInfo = CurPPLexer->peekConditionalLevel();
+
+        bool ShouldEnter;
+        // If this is in a skipping block or if we're already handled this #if
+        // block, don't bother parsing the condition.
+        if (CondInfo.WasSkipping || CondInfo.FoundNonSkip) {
+          DiscardUntilEndOfDirective();
+          ShouldEnter = false;
+        } else {
+          // Restore the value of LexingRawMode so that identifiers are
+          // looked up, etc, inside the #elif expression.
+          assert(CurPPLexer->LexingRawMode && "We have to be skipping here!");
+          CurPPLexer->LexingRawMode = false;
+          IdentifierInfo *IfNDefMacro = 0;
+          ShouldEnter = EvaluateDirectiveExpression(IfNDefMacro);
+          CurPPLexer->LexingRawMode = true;
+        }
+
+        // If this is a #elif with a #else before it, report the error.
+        if (CondInfo.FoundElse) Diag(Tok, diag::pp_err_elif_after_else);
+
+        // If this condition is true, enter it!
+        if (ShouldEnter) {
+          CondInfo.FoundNonSkip = true;
+          break;
+        }
+      }
+    }
+
+    CurPPLexer->ParsingPreprocessorDirective = false;
+    // Restore comment saving mode.
+    if (CurLexer) CurLexer->SetCommentRetentionState(KeepComments);
+  }
+
+  // Finally, if we are out of the conditional (saw an #endif or ran off the end
+  // of the file, just stop skipping and return to lexing whatever came after
+  // the #if block.
+  CurPPLexer->LexingRawMode = false;
+}
+
+void Preprocessor::PTHSkipExcludedConditionalBlock() {
+
+  while (1) {
+    assert(CurPTHLexer);
+    assert(CurPTHLexer->LexingRawMode == false);
+
+    // Skip to the next '#else', '#elif', or #endif.
+    if (CurPTHLexer->SkipBlock()) {
+      // We have reached an #endif.  Both the '#' and 'endif' tokens
+      // have been consumed by the PTHLexer.  Just pop off the condition level.
+      PPConditionalInfo CondInfo;
+      bool InCond = CurPTHLexer->popConditionalLevel(CondInfo);
+      InCond = InCond;  // Silence warning in no-asserts mode.
+      assert(!InCond && "Can't be skipping if not in a conditional!");
+      break;
+    }
+
+    // We have reached a '#else' or '#elif'.  Lex the next token to get
+    // the directive flavor.
+    Token Tok;
+    LexUnexpandedToken(Tok);
+
+    // We can actually look up the IdentifierInfo here since we aren't in
+    // raw mode.
+    tok::PPKeywordKind K = Tok.getIdentifierInfo()->getPPKeywordID();
+
+    if (K == tok::pp_else) {
+      // #else: Enter the else condition.  We aren't in a nested condition
+      //  since we skip those. We're always in the one matching the last
+      //  blocked we skipped.
+      PPConditionalInfo &CondInfo = CurPTHLexer->peekConditionalLevel();
+      // Note that we've seen a #else in this conditional.
+      CondInfo.FoundElse = true;
+
+      // If the #if block wasn't entered then enter the #else block now.
+      if (!CondInfo.FoundNonSkip) {
+        CondInfo.FoundNonSkip = true;
+
+        // Scan until the eom token.
+        CurPTHLexer->ParsingPreprocessorDirective = true;
+        DiscardUntilEndOfDirective();
+        CurPTHLexer->ParsingPreprocessorDirective = false;
+
+        break;
+      }
+
+      // Otherwise skip this block.
+      continue;
+    }
+
+    assert(K == tok::pp_elif);
+    PPConditionalInfo &CondInfo = CurPTHLexer->peekConditionalLevel();
+
+    // If this is a #elif with a #else before it, report the error.
+    if (CondInfo.FoundElse)
+      Diag(Tok, diag::pp_err_elif_after_else);
+
+    // If this is in a skipping block or if we're already handled this #if
+    // block, don't bother parsing the condition.  We just skip this block.
+    if (CondInfo.FoundNonSkip)
+      continue;
+
+    // Evaluate the condition of the #elif.
+    IdentifierInfo *IfNDefMacro = 0;
+    CurPTHLexer->ParsingPreprocessorDirective = true;
+    bool ShouldEnter = EvaluateDirectiveExpression(IfNDefMacro);
+    CurPTHLexer->ParsingPreprocessorDirective = false;
+
+    // If this condition is true, enter it!
+    if (ShouldEnter) {
+      CondInfo.FoundNonSkip = true;
+      break;
+    }
+
+    // Otherwise, skip this block and go to the next one.
+    continue;
+  }
+}
+
+/// LookupFile - Given a "foo" or <foo> reference, look up the indicated file,
+/// return null on failure.  isAngled indicates whether the file reference is
+/// for system #include's or not (i.e. using <> instead of "").
+const FileEntry *Preprocessor::LookupFile(llvm::StringRef Filename,
+                                          bool isAngled,
+                                          const DirectoryLookup *FromDir,
+                                          const DirectoryLookup *&CurDir) {
+  // If the header lookup mechanism may be relative to the current file, pass in
+  // info about where the current file is.
+  const FileEntry *CurFileEnt = 0;
+  if (!FromDir) {
+    FileID FID = getCurrentFileLexer()->getFileID();
+    CurFileEnt = SourceMgr.getFileEntryForID(FID);
+
+    // If there is no file entry associated with this file, it must be the
+    // predefines buffer.  Any other file is not lexed with a normal lexer, so
+    // it won't be scanned for preprocessor directives.   If we have the
+    // predefines buffer, resolve #include references (which come from the
+    // -include command line argument) as if they came from the main file, this
+    // affects file lookup etc.
+    if (CurFileEnt == 0) {
+      FID = SourceMgr.getMainFileID();
+      CurFileEnt = SourceMgr.getFileEntryForID(FID);
+    }
+  }
+
+  // Do a standard file entry lookup.
+  CurDir = CurDirLookup;
+  const FileEntry *FE =
+    HeaderInfo.LookupFile(Filename, isAngled, FromDir, CurDir, CurFileEnt);
+  if (FE) return FE;
+
+  // Otherwise, see if this is a subframework header.  If so, this is relative
+  // to one of the headers on the #include stack.  Walk the list of the current
+  // headers on the #include stack and pass them to HeaderInfo.
+  if (IsFileLexer()) {
+    if ((CurFileEnt = SourceMgr.getFileEntryForID(CurPPLexer->getFileID())))
+      if ((FE = HeaderInfo.LookupSubframeworkHeader(Filename, CurFileEnt)))
+        return FE;
+  }
+
+  for (unsigned i = 0, e = IncludeMacroStack.size(); i != e; ++i) {
+    IncludeStackInfo &ISEntry = IncludeMacroStack[e-i-1];
+    if (IsFileLexer(ISEntry)) {
+      if ((CurFileEnt =
+           SourceMgr.getFileEntryForID(ISEntry.ThePPLexer->getFileID())))
+        if ((FE = HeaderInfo.LookupSubframeworkHeader(Filename, CurFileEnt)))
+          return FE;
+    }
+  }
+
+  // Otherwise, we really couldn't find the file.
+  return 0;
+}
+
+
+//===----------------------------------------------------------------------===//
+// Preprocessor Directive Handling.
+//===----------------------------------------------------------------------===//
+
+/// HandleDirective - This callback is invoked when the lexer sees a # token
+/// at the start of a line.  This consumes the directive, modifies the
+/// lexer/preprocessor state, and advances the lexer(s) so that the next token
+/// read is the correct one.
+void Preprocessor::HandleDirective(Token &Result) {
+  // FIXME: Traditional: # with whitespace before it not recognized by K&R?
+
+  // We just parsed a # character at the start of a line, so we're in directive
+  // mode.  Tell the lexer this so any newlines we see will be converted into an
+  // EOM token (which terminates the directive).
+  CurPPLexer->ParsingPreprocessorDirective = true;
+
+  ++NumDirectives;
+  
+  // We are about to read a token.  For the multiple-include optimization FA to
+  // work, we have to remember if we had read any tokens *before* this
+  // pp-directive.
+  bool ReadAnyTokensBeforeDirective =CurPPLexer->MIOpt.getHasReadAnyTokensVal();
+
+  // Save the '#' token in case we need to return it later.
+  Token SavedHash = Result;
+
+  // Read the next token, the directive flavor.  This isn't expanded due to
+  // C99 6.10.3p8.
+  LexUnexpandedToken(Result);
+
+  // C99 6.10.3p11: Is this preprocessor directive in macro invocation?  e.g.:
+  //   #define A(x) #x
+  //   A(abc
+  //     #warning blah
+  //   def)
+  // If so, the user is relying on non-portable behavior, emit a diagnostic.
+  if (InMacroArgs)
+    Diag(Result, diag::ext_embedded_directive);
+
+TryAgain:
+  switch (Result.getKind()) {
+  case tok::eom:
+    return;   // null directive.
+  case tok::comment:
+    // Handle stuff like "# /*foo*/ define X" in -E -C mode.
+    LexUnexpandedToken(Result);
+    goto TryAgain;
+
+  case tok::numeric_constant:  // # 7  GNU line marker directive.
+    if (getLangOptions().AsmPreprocessor)
+      break;  // # 4 is not a preprocessor directive in .S files.
+    return HandleDigitDirective(Result);
+  default:
+    IdentifierInfo *II = Result.getIdentifierInfo();
+    if (II == 0) break;  // Not an identifier.
+
+    // Ask what the preprocessor keyword ID is.
+    switch (II->getPPKeywordID()) {
+    default: break;
+    // C99 6.10.1 - Conditional Inclusion.
+    case tok::pp_if:
+      return HandleIfDirective(Result, ReadAnyTokensBeforeDirective);
+    case tok::pp_ifdef:
+      return HandleIfdefDirective(Result, false, true/*not valid for miopt*/);
+    case tok::pp_ifndef:
+      return HandleIfdefDirective(Result, true, ReadAnyTokensBeforeDirective);
+    case tok::pp_elif:
+      return HandleElifDirective(Result);
+    case tok::pp_else:
+      return HandleElseDirective(Result);
+    case tok::pp_endif:
+      return HandleEndifDirective(Result);
+
+    // C99 6.10.2 - Source File Inclusion.
+    case tok::pp_include:
+      return HandleIncludeDirective(Result);       // Handle #include.
+    case tok::pp___include_macros:
+      return HandleIncludeMacrosDirective(Result); // Handle -imacros.
+
+    // C99 6.10.3 - Macro Replacement.
+    case tok::pp_define:
+      return HandleDefineDirective(Result);
+    case tok::pp_undef:
+      return HandleUndefDirective(Result);
+
+    // C99 6.10.4 - Line Control.
+    case tok::pp_line:
+      return HandleLineDirective(Result);
+
+    // C99 6.10.5 - Error Directive.
+    case tok::pp_error:
+      return HandleUserDiagnosticDirective(Result, false);
+
+    // C99 6.10.6 - Pragma Directive.
+    case tok::pp_pragma:
+      return HandlePragmaDirective();
+
+    // GNU Extensions.
+    case tok::pp_import:
+      return HandleImportDirective(Result);
+    case tok::pp_include_next:
+      return HandleIncludeNextDirective(Result);
+
+    case tok::pp_warning:
+      Diag(Result, diag::ext_pp_warning_directive);
+      return HandleUserDiagnosticDirective(Result, true);
+    case tok::pp_ident:
+      return HandleIdentSCCSDirective(Result);
+    case tok::pp_sccs:
+      return HandleIdentSCCSDirective(Result);
+    case tok::pp_assert:
+      //isExtension = true;  // FIXME: implement #assert
+      break;
+    case tok::pp_unassert:
+      //isExtension = true;  // FIXME: implement #unassert
+      break;
+    }
+    break;
+  }
+
+  // If this is a .S file, treat unknown # directives as non-preprocessor
+  // directives.  This is important because # may be a comment or introduce
+  // various pseudo-ops.  Just return the # token and push back the following
+  // token to be lexed next time.
+  if (getLangOptions().AsmPreprocessor) {
+    Token *Toks = new Token[2];
+    // Return the # and the token after it.
+    Toks[0] = SavedHash;
+    Toks[1] = Result;
+    // Enter this token stream so that we re-lex the tokens.  Make sure to
+    // enable macro expansion, in case the token after the # is an identifier
+    // that is expanded.
+    EnterTokenStream(Toks, 2, false, true);
+    return;
+  }
+
+  // If we reached here, the preprocessing token is not valid!
+  Diag(Result, diag::err_pp_invalid_directive);
+
+  // Read the rest of the PP line.
+  DiscardUntilEndOfDirective();
+
+  // Okay, we're done parsing the directive.
+}
+
+/// GetLineValue - Convert a numeric token into an unsigned value, emitting
+/// Diagnostic DiagID if it is invalid, and returning the value in Val.
+static bool GetLineValue(Token &DigitTok, unsigned &Val,
+                         unsigned DiagID, Preprocessor &PP) {
+  if (DigitTok.isNot(tok::numeric_constant)) {
+    PP.Diag(DigitTok, DiagID);
+
+    if (DigitTok.isNot(tok::eom))
+      PP.DiscardUntilEndOfDirective();
+    return true;
+  }
+
+  llvm::SmallString<64> IntegerBuffer;
+  IntegerBuffer.resize(DigitTok.getLength());
+  const char *DigitTokBegin = &IntegerBuffer[0];
+  unsigned ActualLength = PP.getSpelling(DigitTok, DigitTokBegin);
+
+  // Verify that we have a simple digit-sequence, and compute the value.  This
+  // is always a simple digit string computed in decimal, so we do this manually
+  // here.
+  Val = 0;
+  for (unsigned i = 0; i != ActualLength; ++i) {
+    if (!isdigit(DigitTokBegin[i])) {
+      PP.Diag(PP.AdvanceToTokenCharacter(DigitTok.getLocation(), i),
+              diag::err_pp_line_digit_sequence);
+      PP.DiscardUntilEndOfDirective();
+      return true;
+    }
+
+    unsigned NextVal = Val*10+(DigitTokBegin[i]-'0');
+    if (NextVal < Val) { // overflow.
+      PP.Diag(DigitTok, DiagID);
+      PP.DiscardUntilEndOfDirective();
+      return true;
+    }
+    Val = NextVal;
+  }
+
+  // Reject 0, this is needed both by #line numbers and flags.
+  if (Val == 0) {
+    PP.Diag(DigitTok, DiagID);
+    PP.DiscardUntilEndOfDirective();
+    return true;
+  }
+
+  if (DigitTokBegin[0] == '0')
+    PP.Diag(DigitTok.getLocation(), diag::warn_pp_line_decimal);
+
+  return false;
+}
+
+/// HandleLineDirective - Handle #line directive: C99 6.10.4.  The two
+/// acceptable forms are:
+///   # line digit-sequence
+///   # line digit-sequence "s-char-sequence"
+void Preprocessor::HandleLineDirective(Token &Tok) {
+  // Read the line # and string argument.  Per C99 6.10.4p5, these tokens are
+  // expanded.
+  Token DigitTok;
+  Lex(DigitTok);
+
+  // Validate the number and convert it to an unsigned.
+  unsigned LineNo;
+  if (GetLineValue(DigitTok, LineNo, diag::err_pp_line_requires_integer,*this))
+    return;
+
+  // Enforce C99 6.10.4p3: "The digit sequence shall not specify ... a
+  // number greater than 2147483647".  C90 requires that the line # be <= 32767.
+  unsigned LineLimit = Features.C99 ? 2147483648U : 32768U;
+  if (LineNo >= LineLimit)
+    Diag(DigitTok, diag::ext_pp_line_too_big) << LineLimit;
+
+  int FilenameID = -1;
+  Token StrTok;
+  Lex(StrTok);
+
+  // If the StrTok is "eom", then it wasn't present.  Otherwise, it must be a
+  // string followed by eom.
+  if (StrTok.is(tok::eom))
+    ; // ok
+  else if (StrTok.isNot(tok::string_literal)) {
+    Diag(StrTok, diag::err_pp_line_invalid_filename);
+    DiscardUntilEndOfDirective();
+    return;
+  } else {
+    // Parse and validate the string, converting it into a unique ID.
+    StringLiteralParser Literal(&StrTok, 1, *this);
+    assert(!Literal.AnyWide && "Didn't allow wide strings in");
+    if (Literal.hadError)
+      return DiscardUntilEndOfDirective();
+    if (Literal.Pascal) {
+      Diag(StrTok, diag::err_pp_linemarker_invalid_filename);
+      return DiscardUntilEndOfDirective();
+    }
+    FilenameID = SourceMgr.getLineTableFilenameID(Literal.GetString(),
+                                                  Literal.GetStringLength());
+
+    // Verify that there is nothing after the string, other than EOM.  Because
+    // of C99 6.10.4p5, macros that expand to empty tokens are ok.
+    CheckEndOfDirective("line", true);
+  }
+
+  SourceMgr.AddLineNote(DigitTok.getLocation(), LineNo, FilenameID);
+
+  if (Callbacks)
+    Callbacks->FileChanged(DigitTok.getLocation(), PPCallbacks::RenameFile,
+                           SrcMgr::C_User);
+}
+
+/// ReadLineMarkerFlags - Parse and validate any flags at the end of a GNU line
+/// marker directive.
+static bool ReadLineMarkerFlags(bool &IsFileEntry, bool &IsFileExit,
+                                bool &IsSystemHeader, bool &IsExternCHeader,
+                                Preprocessor &PP) {
+  unsigned FlagVal;
+  Token FlagTok;
+  PP.Lex(FlagTok);
+  if (FlagTok.is(tok::eom)) return false;
+  if (GetLineValue(FlagTok, FlagVal, diag::err_pp_linemarker_invalid_flag, PP))
+    return true;
+
+  if (FlagVal == 1) {
+    IsFileEntry = true;
+
+    PP.Lex(FlagTok);
+    if (FlagTok.is(tok::eom)) return false;
+    if (GetLineValue(FlagTok, FlagVal, diag::err_pp_linemarker_invalid_flag,PP))
+      return true;
+  } else if (FlagVal == 2) {
+    IsFileExit = true;
+
+    SourceManager &SM = PP.getSourceManager();
+    // If we are leaving the current presumed file, check to make sure the
+    // presumed include stack isn't empty!
+    FileID CurFileID =
+      SM.getDecomposedInstantiationLoc(FlagTok.getLocation()).first;
+    PresumedLoc PLoc = SM.getPresumedLoc(FlagTok.getLocation());
+
+    // If there is no include loc (main file) or if the include loc is in a
+    // different physical file, then we aren't in a "1" line marker flag region.
+    SourceLocation IncLoc = PLoc.getIncludeLoc();
+    if (IncLoc.isInvalid() ||
+        SM.getDecomposedInstantiationLoc(IncLoc).first != CurFileID) {
+      PP.Diag(FlagTok, diag::err_pp_linemarker_invalid_pop);
+      PP.DiscardUntilEndOfDirective();
+      return true;
+    }
+
+    PP.Lex(FlagTok);
+    if (FlagTok.is(tok::eom)) return false;
+    if (GetLineValue(FlagTok, FlagVal, diag::err_pp_linemarker_invalid_flag,PP))
+      return true;
+  }
+
+  // We must have 3 if there are still flags.
+  if (FlagVal != 3) {
+    PP.Diag(FlagTok, diag::err_pp_linemarker_invalid_flag);
+    PP.DiscardUntilEndOfDirective();
+    return true;
+  }
+
+  IsSystemHeader = true;
+
+  PP.Lex(FlagTok);
+  if (FlagTok.is(tok::eom)) return false;
+  if (GetLineValue(FlagTok, FlagVal, diag::err_pp_linemarker_invalid_flag, PP))
+    return true;
+
+  // We must have 4 if there is yet another flag.
+  if (FlagVal != 4) {
+    PP.Diag(FlagTok, diag::err_pp_linemarker_invalid_flag);
+    PP.DiscardUntilEndOfDirective();
+    return true;
+  }
+
+  IsExternCHeader = true;
+
+  PP.Lex(FlagTok);
+  if (FlagTok.is(tok::eom)) return false;
+
+  // There are no more valid flags here.
+  PP.Diag(FlagTok, diag::err_pp_linemarker_invalid_flag);
+  PP.DiscardUntilEndOfDirective();
+  return true;
+}
+
+/// HandleDigitDirective - Handle a GNU line marker directive, whose syntax is
+/// one of the following forms:
+///
+///     # 42
+///     # 42 "file" ('1' | '2')?
+///     # 42 "file" ('1' | '2')? '3' '4'?
+///
+void Preprocessor::HandleDigitDirective(Token &DigitTok) {
+  // Validate the number and convert it to an unsigned.  GNU does not have a
+  // line # limit other than it fit in 32-bits.
+  unsigned LineNo;
+  if (GetLineValue(DigitTok, LineNo, diag::err_pp_linemarker_requires_integer,
+                   *this))
+    return;
+
+  Token StrTok;
+  Lex(StrTok);
+
+  bool IsFileEntry = false, IsFileExit = false;
+  bool IsSystemHeader = false, IsExternCHeader = false;
+  int FilenameID = -1;
+
+  // If the StrTok is "eom", then it wasn't present.  Otherwise, it must be a
+  // string followed by eom.
+  if (StrTok.is(tok::eom))
+    ; // ok
+  else if (StrTok.isNot(tok::string_literal)) {
+    Diag(StrTok, diag::err_pp_linemarker_invalid_filename);
+    return DiscardUntilEndOfDirective();
+  } else {
+    // Parse and validate the string, converting it into a unique ID.
+    StringLiteralParser Literal(&StrTok, 1, *this);
+    assert(!Literal.AnyWide && "Didn't allow wide strings in");
+    if (Literal.hadError)
+      return DiscardUntilEndOfDirective();
+    if (Literal.Pascal) {
+      Diag(StrTok, diag::err_pp_linemarker_invalid_filename);
+      return DiscardUntilEndOfDirective();
+    }
+    FilenameID = SourceMgr.getLineTableFilenameID(Literal.GetString(),
+                                                  Literal.GetStringLength());
+
+    // If a filename was present, read any flags that are present.
+    if (ReadLineMarkerFlags(IsFileEntry, IsFileExit,
+                            IsSystemHeader, IsExternCHeader, *this))
+      return;
+  }
+
+  // Create a line note with this information.
+  SourceMgr.AddLineNote(DigitTok.getLocation(), LineNo, FilenameID,
+                        IsFileEntry, IsFileExit,
+                        IsSystemHeader, IsExternCHeader);
+
+  // If the preprocessor has callbacks installed, notify them of the #line
+  // change.  This is used so that the line marker comes out in -E mode for
+  // example.
+  if (Callbacks) {
+    PPCallbacks::FileChangeReason Reason = PPCallbacks::RenameFile;
+    if (IsFileEntry)
+      Reason = PPCallbacks::EnterFile;
+    else if (IsFileExit)
+      Reason = PPCallbacks::ExitFile;
+    SrcMgr::CharacteristicKind FileKind = SrcMgr::C_User;
+    if (IsExternCHeader)
+      FileKind = SrcMgr::C_ExternCSystem;
+    else if (IsSystemHeader)
+      FileKind = SrcMgr::C_System;
+
+    Callbacks->FileChanged(DigitTok.getLocation(), Reason, FileKind);
+  }
+}
+
+
+/// HandleUserDiagnosticDirective - Handle a #warning or #error directive.
+///
+void Preprocessor::HandleUserDiagnosticDirective(Token &Tok,
+                                                 bool isWarning) {
+  // PTH doesn't emit #warning or #error directives.
+  if (CurPTHLexer)
+    return CurPTHLexer->DiscardToEndOfLine();
+
+  // Read the rest of the line raw.  We do this because we don't want macros
+  // to be expanded and we don't require that the tokens be valid preprocessing
+  // tokens.  For example, this is allowed: "#warning `   'foo".  GCC does
+  // collapse multiple consequtive white space between tokens, but this isn't
+  // specified by the standard.
+  std::string Message = CurLexer->ReadToEndOfLine();
+  if (isWarning)
+    Diag(Tok, diag::pp_hash_warning) << Message;
+  else
+    Diag(Tok, diag::err_pp_hash_error) << Message;
+}
+
+/// HandleIdentSCCSDirective - Handle a #ident/#sccs directive.
+///
+void Preprocessor::HandleIdentSCCSDirective(Token &Tok) {
+  // Yes, this directive is an extension.
+  Diag(Tok, diag::ext_pp_ident_directive);
+
+  // Read the string argument.
+  Token StrTok;
+  Lex(StrTok);
+
+  // If the token kind isn't a string, it's a malformed directive.
+  if (StrTok.isNot(tok::string_literal) &&
+      StrTok.isNot(tok::wide_string_literal)) {
+    Diag(StrTok, diag::err_pp_malformed_ident);
+    if (StrTok.isNot(tok::eom))
+      DiscardUntilEndOfDirective();
+    return;
+  }
+
+  // Verify that there is nothing after the string, other than EOM.
+  CheckEndOfDirective("ident");
+
+  if (Callbacks)
+    Callbacks->Ident(Tok.getLocation(), getSpelling(StrTok));
+}
+
+//===----------------------------------------------------------------------===//
+// Preprocessor Include Directive Handling.
+//===----------------------------------------------------------------------===//
+
+/// GetIncludeFilenameSpelling - Turn the specified lexer token into a fully
+/// checked and spelled filename, e.g. as an operand of #include. This returns
+/// true if the input filename was in <>'s or false if it were in ""'s.  The
+/// caller is expected to provide a buffer that is large enough to hold the
+/// spelling of the filename, but is also expected to handle the case when
+/// this method decides to use a different buffer.
+bool Preprocessor::GetIncludeFilenameSpelling(SourceLocation Loc,
+                                              llvm::StringRef &Buffer) {
+  // Get the text form of the filename.
+  assert(!Buffer.empty() && "Can't have tokens with empty spellings!");
+
+  // Make sure the filename is <x> or "x".
+  bool isAngled;
+  if (Buffer[0] == '<') {
+    if (Buffer.back() != '>') {
+      Diag(Loc, diag::err_pp_expects_filename);
+      Buffer = llvm::StringRef();
+      return true;
+    }
+    isAngled = true;
+  } else if (Buffer[0] == '"') {
+    if (Buffer.back() != '"') {
+      Diag(Loc, diag::err_pp_expects_filename);
+      Buffer = llvm::StringRef();
+      return true;
+    }
+    isAngled = false;
+  } else {
+    Diag(Loc, diag::err_pp_expects_filename);
+    Buffer = llvm::StringRef();
+    return true;
+  }
+
+  // Diagnose #include "" as invalid.
+  if (Buffer.size() <= 2) {
+    Diag(Loc, diag::err_pp_empty_filename);
+    Buffer = llvm::StringRef();
+    return true;
+  }
+
+  // Skip the brackets.
+  Buffer = Buffer.substr(1, Buffer.size()-2);
+  return isAngled;
+}
+
+/// ConcatenateIncludeName - Handle cases where the #include name is expanded
+/// from a macro as multiple tokens, which need to be glued together.  This
+/// occurs for code like:
+///    #define FOO <a/b.h>
+///    #include FOO
+/// because in this case, "<a/b.h>" is returned as 7 tokens, not one.
+///
+/// This code concatenates and consumes tokens up to the '>' token.  It returns
+/// false if the > was found, otherwise it returns true if it finds and consumes
+/// the EOM marker.
+bool Preprocessor::ConcatenateIncludeName(
+  llvm::SmallVector<char, 128> &FilenameBuffer) {
+  Token CurTok;
+
+  Lex(CurTok);
+  while (CurTok.isNot(tok::eom)) {
+    // Append the spelling of this token to the buffer. If there was a space
+    // before it, add it now.
+    if (CurTok.hasLeadingSpace())
+      FilenameBuffer.push_back(' ');
+
+    // Get the spelling of the token, directly into FilenameBuffer if possible.
+    unsigned PreAppendSize = FilenameBuffer.size();
+    FilenameBuffer.resize(PreAppendSize+CurTok.getLength());
+
+    const char *BufPtr = &FilenameBuffer[PreAppendSize];
+    unsigned ActualLen = getSpelling(CurTok, BufPtr);
+
+    // If the token was spelled somewhere else, copy it into FilenameBuffer.
+    if (BufPtr != &FilenameBuffer[PreAppendSize])
+      memcpy(&FilenameBuffer[PreAppendSize], BufPtr, ActualLen);
+
+    // Resize FilenameBuffer to the correct size.
+    if (CurTok.getLength() != ActualLen)
+      FilenameBuffer.resize(PreAppendSize+ActualLen);
+
+    // If we found the '>' marker, return success.
+    if (CurTok.is(tok::greater))
+      return false;
+
+    Lex(CurTok);
+  }
+
+  // If we hit the eom marker, emit an error and return true so that the caller
+  // knows the EOM has been read.
+  Diag(CurTok.getLocation(), diag::err_pp_expects_filename);
+  return true;
+}
+
+/// HandleIncludeDirective - The "#include" tokens have just been read, read the
+/// file to be included from the lexer, then include it!  This is a common
+/// routine with functionality shared between #include, #include_next and
+/// #import.  LookupFrom is set when this is a #include_next directive, it
+/// specifies the file to start searching from.
+void Preprocessor::HandleIncludeDirective(Token &IncludeTok,
+                                          const DirectoryLookup *LookupFrom,
+                                          bool isImport) {
+
+  Token FilenameTok;
+  CurPPLexer->LexIncludeFilename(FilenameTok);
+
+  // Reserve a buffer to get the spelling.
+  llvm::SmallString<128> FilenameBuffer;
+  llvm::StringRef Filename;
+
+  switch (FilenameTok.getKind()) {
+  case tok::eom:
+    // If the token kind is EOM, the error has already been diagnosed.
+    return;
+
+  case tok::angle_string_literal:
+  case tok::string_literal: {
+    FilenameBuffer.resize(FilenameTok.getLength());
+    const char *FilenameStart = &FilenameBuffer[0];
+    unsigned Len = getSpelling(FilenameTok, FilenameStart);
+    Filename = llvm::StringRef(FilenameStart, Len);
+    break;
+  }
+
+  case tok::less:
+    // This could be a <foo/bar.h> file coming from a macro expansion.  In this
+    // case, glue the tokens together into FilenameBuffer and interpret those.
+    FilenameBuffer.push_back('<');
+    if (ConcatenateIncludeName(FilenameBuffer))
+      return;   // Found <eom> but no ">"?  Diagnostic already emitted.
+    Filename = FilenameBuffer.str();
+    break;
+  default:
+    Diag(FilenameTok.getLocation(), diag::err_pp_expects_filename);
+    DiscardUntilEndOfDirective();
+    return;
+  }
+
+  bool isAngled = 
+    GetIncludeFilenameSpelling(FilenameTok.getLocation(), Filename);
+  // If GetIncludeFilenameSpelling set the start ptr to null, there was an
+  // error.
+  if (Filename.empty()) {
+    DiscardUntilEndOfDirective();
+    return;
+  }
+
+  // Verify that there is nothing after the filename, other than EOM.  Note that
+  // we allow macros that expand to nothing after the filename, because this
+  // falls into the category of "#include pp-tokens new-line" specified in
+  // C99 6.10.2p4.
+  CheckEndOfDirective(IncludeTok.getIdentifierInfo()->getNameStart(), true);
+
+  // Check that we don't have infinite #include recursion.
+  if (IncludeMacroStack.size() == MaxAllowedIncludeStackDepth-1) {
+    Diag(FilenameTok, diag::err_pp_include_too_deep);
+    return;
+  }
+
+  // Search include directories.
+  const DirectoryLookup *CurDir;
+  const FileEntry *File = LookupFile(Filename, isAngled, LookupFrom, CurDir);
+  if (File == 0) {
+    Diag(FilenameTok, diag::err_pp_file_not_found) << Filename;
+    return;
+  }
+  
+  // Ask HeaderInfo if we should enter this #include file.  If not, #including
+  // this file will have no effect.
+  if (!HeaderInfo.ShouldEnterIncludeFile(File, isImport))
+    return;
+
+  // The #included file will be considered to be a system header if either it is
+  // in a system include directory, or if the #includer is a system include
+  // header.
+  SrcMgr::CharacteristicKind FileCharacter =
+    std::max(HeaderInfo.getFileDirFlavor(File),
+             SourceMgr.getFileCharacteristic(FilenameTok.getLocation()));
+
+  // Look up the file, create a File ID for it.
+  FileID FID = SourceMgr.createFileID(File, FilenameTok.getLocation(),
+                                      FileCharacter);
+  if (FID.isInvalid()) {
+    Diag(FilenameTok, diag::err_pp_file_not_found) << Filename;
+    return;
+  }
+
+  // Finally, if all is good, enter the new file!
+  std::string ErrorStr;
+  if (EnterSourceFile(FID, CurDir, ErrorStr))
+    Diag(FilenameTok, diag::err_pp_error_opening_file)
+      << std::string(SourceMgr.getFileEntryForID(FID)->getName()) << ErrorStr;
+}
+
+/// HandleIncludeNextDirective - Implements #include_next.
+///
+void Preprocessor::HandleIncludeNextDirective(Token &IncludeNextTok) {
+  Diag(IncludeNextTok, diag::ext_pp_include_next_directive);
+
+  // #include_next is like #include, except that we start searching after
+  // the current found directory.  If we can't do this, issue a
+  // diagnostic.
+  const DirectoryLookup *Lookup = CurDirLookup;
+  if (isInPrimaryFile()) {
+    Lookup = 0;
+    Diag(IncludeNextTok, diag::pp_include_next_in_primary);
+  } else if (Lookup == 0) {
+    Diag(IncludeNextTok, diag::pp_include_next_absolute_path);
+  } else {
+    // Start looking up in the next directory.
+    ++Lookup;
+  }
+
+  return HandleIncludeDirective(IncludeNextTok, Lookup);
+}
+
+/// HandleImportDirective - Implements #import.
+///
+void Preprocessor::HandleImportDirective(Token &ImportTok) {
+  if (!Features.ObjC1)  // #import is standard for ObjC.
+    Diag(ImportTok, diag::ext_pp_import_directive);
+
+  return HandleIncludeDirective(ImportTok, 0, true);
+}
+
+/// HandleIncludeMacrosDirective - The -imacros command line option turns into a
+/// pseudo directive in the predefines buffer.  This handles it by sucking all
+/// tokens through the preprocessor and discarding them (only keeping the side
+/// effects on the preprocessor).
+void Preprocessor::HandleIncludeMacrosDirective(Token &IncludeMacrosTok) {
+  // This directive should only occur in the predefines buffer.  If not, emit an
+  // error and reject it.
+  SourceLocation Loc = IncludeMacrosTok.getLocation();
+  if (strcmp(SourceMgr.getBufferName(Loc), "<built-in>") != 0) {
+    Diag(IncludeMacrosTok.getLocation(),
+         diag::pp_include_macros_out_of_predefines);
+    DiscardUntilEndOfDirective();
+    return;
+  }
+
+  // Treat this as a normal #include for checking purposes.  If this is
+  // successful, it will push a new lexer onto the include stack.
+  HandleIncludeDirective(IncludeMacrosTok, 0, false);
+
+  Token TmpTok;
+  do {
+    Lex(TmpTok);
+    assert(TmpTok.isNot(tok::eof) && "Didn't find end of -imacros!");
+  } while (TmpTok.isNot(tok::hashhash));
+}
+
+//===----------------------------------------------------------------------===//
+// Preprocessor Macro Directive Handling.
+//===----------------------------------------------------------------------===//
+
+/// ReadMacroDefinitionArgList - The ( starting an argument list of a macro
+/// definition has just been read.  Lex the rest of the arguments and the
+/// closing ), updating MI with what we learn.  Return true if an error occurs
+/// parsing the arg list.
+bool Preprocessor::ReadMacroDefinitionArgList(MacroInfo *MI) {
+  llvm::SmallVector<IdentifierInfo*, 32> Arguments;
+
+  Token Tok;
+  while (1) {
+    LexUnexpandedToken(Tok);
+    switch (Tok.getKind()) {
+    case tok::r_paren:
+      // Found the end of the argument list.
+      if (Arguments.empty())  // #define FOO()
+        return false;
+      // Otherwise we have #define FOO(A,)
+      Diag(Tok, diag::err_pp_expected_ident_in_arg_list);
+      return true;
+    case tok::ellipsis:  // #define X(... -> C99 varargs
+      // Warn if use of C99 feature in non-C99 mode.
+      if (!Features.C99) Diag(Tok, diag::ext_variadic_macro);
+
+      // Lex the token after the identifier.
+      LexUnexpandedToken(Tok);
+      if (Tok.isNot(tok::r_paren)) {
+        Diag(Tok, diag::err_pp_missing_rparen_in_macro_def);
+        return true;
+      }
+      // Add the __VA_ARGS__ identifier as an argument.
+      Arguments.push_back(Ident__VA_ARGS__);
+      MI->setIsC99Varargs();
+      MI->setArgumentList(&Arguments[0], Arguments.size(), BP);
+      return false;
+    case tok::eom:  // #define X(
+      Diag(Tok, diag::err_pp_missing_rparen_in_macro_def);
+      return true;
+    default:
+      // Handle keywords and identifiers here to accept things like
+      // #define Foo(for) for.
+      IdentifierInfo *II = Tok.getIdentifierInfo();
+      if (II == 0) {
+        // #define X(1
+        Diag(Tok, diag::err_pp_invalid_tok_in_arg_list);
+        return true;
+      }
+
+      // If this is already used as an argument, it is used multiple times (e.g.
+      // #define X(A,A.
+      if (std::find(Arguments.begin(), Arguments.end(), II) !=
+          Arguments.end()) {  // C99 6.10.3p6
+        Diag(Tok, diag::err_pp_duplicate_name_in_arg_list) << II;
+        return true;
+      }
+
+      // Add the argument to the macro info.
+      Arguments.push_back(II);
+
+      // Lex the token after the identifier.
+      LexUnexpandedToken(Tok);
+
+      switch (Tok.getKind()) {
+      default:          // #define X(A B
+        Diag(Tok, diag::err_pp_expected_comma_in_arg_list);
+        return true;
+      case tok::r_paren: // #define X(A)
+        MI->setArgumentList(&Arguments[0], Arguments.size(), BP);
+        return false;
+      case tok::comma:  // #define X(A,
+        break;
+      case tok::ellipsis:  // #define X(A... -> GCC extension
+        // Diagnose extension.
+        Diag(Tok, diag::ext_named_variadic_macro);
+
+        // Lex the token after the identifier.
+        LexUnexpandedToken(Tok);
+        if (Tok.isNot(tok::r_paren)) {
+          Diag(Tok, diag::err_pp_missing_rparen_in_macro_def);
+          return true;
+        }
+
+        MI->setIsGNUVarargs();
+        MI->setArgumentList(&Arguments[0], Arguments.size(), BP);
+        return false;
+      }
+    }
+  }
+}
+
+/// HandleDefineDirective - Implements #define.  This consumes the entire macro
+/// line then lets the caller lex the next real token.
+void Preprocessor::HandleDefineDirective(Token &DefineTok) {
+  ++NumDefined;
+
+  Token MacroNameTok;
+  ReadMacroName(MacroNameTok, 1);
+
+  // Error reading macro name?  If so, diagnostic already issued.
+  if (MacroNameTok.is(tok::eom))
+    return;
+
+  Token LastTok = MacroNameTok;
+
+  // If we are supposed to keep comments in #defines, reenable comment saving
+  // mode.
+  if (CurLexer) CurLexer->SetCommentRetentionState(KeepMacroComments);
+
+  // Create the new macro.
+  MacroInfo *MI = AllocateMacroInfo(MacroNameTok.getLocation());
+
+  Token Tok;
+  LexUnexpandedToken(Tok);
+
+  // If this is a function-like macro definition, parse the argument list,
+  // marking each of the identifiers as being used as macro arguments.  Also,
+  // check other constraints on the first token of the macro body.
+  if (Tok.is(tok::eom)) {
+    // If there is no body to this macro, we have no special handling here.
+  } else if (Tok.hasLeadingSpace()) {
+    // This is a normal token with leading space.  Clear the leading space
+    // marker on the first token to get proper expansion.
+    Tok.clearFlag(Token::LeadingSpace);
+  } else if (Tok.is(tok::l_paren)) {
+    // This is a function-like macro definition.  Read the argument list.
+    MI->setIsFunctionLike();
+    if (ReadMacroDefinitionArgList(MI)) {
+      // Forget about MI.
+      ReleaseMacroInfo(MI);
+      // Throw away the rest of the line.
+      if (CurPPLexer->ParsingPreprocessorDirective)
+        DiscardUntilEndOfDirective();
+      return;
+    }
+
+    // If this is a definition of a variadic C99 function-like macro, not using
+    // the GNU named varargs extension, enabled __VA_ARGS__.
+
+    // "Poison" __VA_ARGS__, which can only appear in the expansion of a macro.
+    // This gets unpoisoned where it is allowed.
+    assert(Ident__VA_ARGS__->isPoisoned() && "__VA_ARGS__ should be poisoned!");
+    if (MI->isC99Varargs())
+      Ident__VA_ARGS__->setIsPoisoned(false);
+
+    // Read the first token after the arg list for down below.
+    LexUnexpandedToken(Tok);
+  } else if (Features.C99) {
+    // C99 requires whitespace between the macro definition and the body.  Emit
+    // a diagnostic for something like "#define X+".
+    Diag(Tok, diag::ext_c99_whitespace_required_after_macro_name);
+  } else {
+    // C90 6.8 TC1 says: "In the definition of an object-like macro, if the
+    // first character of a replacement list is not a character required by
+    // subclause 5.2.1, then there shall be white-space separation between the
+    // identifier and the replacement list.".  5.2.1 lists this set:
+    //   "A-Za-z0-9!"#%&'()*+,_./:;<=>?[\]^_{|}~" as well as whitespace, which
+    // is irrelevant here.
+    bool isInvalid = false;
+    if (Tok.is(tok::at)) // @ is not in the list above.
+      isInvalid = true;
+    else if (Tok.is(tok::unknown)) {
+      // If we have an unknown token, it is something strange like "`".  Since
+      // all of valid characters would have lexed into a single character
+      // token of some sort, we know this is not a valid case.
+      isInvalid = true;
+    }
+    if (isInvalid)
+      Diag(Tok, diag::ext_missing_whitespace_after_macro_name);
+    else
+      Diag(Tok, diag::warn_missing_whitespace_after_macro_name);
+  }
+
+  if (!Tok.is(tok::eom))
+    LastTok = Tok;
+
+  // Read the rest of the macro body.
+  if (MI->isObjectLike()) {
+    // Object-like macros are very simple, just read their body.
+    while (Tok.isNot(tok::eom)) {
+      LastTok = Tok;
+      MI->AddTokenToBody(Tok);
+      // Get the next token of the macro.
+      LexUnexpandedToken(Tok);
+    }
+
+  } else {
+    // Otherwise, read the body of a function-like macro.  While we are at it,
+    // check C99 6.10.3.2p1: ensure that # operators are followed by macro
+    // parameters in function-like macro expansions.
+    while (Tok.isNot(tok::eom)) {
+      LastTok = Tok;
+
+      if (Tok.isNot(tok::hash)) {
+        MI->AddTokenToBody(Tok);
+
+        // Get the next token of the macro.
+        LexUnexpandedToken(Tok);
+        continue;
+      }
+
+      // Get the next token of the macro.
+      LexUnexpandedToken(Tok);
+
+      // Check for a valid macro arg identifier.
+      if (Tok.getIdentifierInfo() == 0 ||
+          MI->getArgumentNum(Tok.getIdentifierInfo()) == -1) {
+
+        // If this is assembler-with-cpp mode, we accept random gibberish after
+        // the '#' because '#' is often a comment character.  However, change
+        // the kind of the token to tok::unknown so that the preprocessor isn't
+        // confused.
+        if (getLangOptions().AsmPreprocessor && Tok.isNot(tok::eom)) {
+          LastTok.setKind(tok::unknown);
+        } else {
+          Diag(Tok, diag::err_pp_stringize_not_parameter);
+          ReleaseMacroInfo(MI);
+
+          // Disable __VA_ARGS__ again.
+          Ident__VA_ARGS__->setIsPoisoned(true);
+          return;
+        }
+      }
+
+      // Things look ok, add the '#' and param name tokens to the macro.
+      MI->AddTokenToBody(LastTok);
+      MI->AddTokenToBody(Tok);
+      LastTok = Tok;
+
+      // Get the next token of the macro.
+      LexUnexpandedToken(Tok);
+    }
+  }
+
+
+  // Disable __VA_ARGS__ again.
+  Ident__VA_ARGS__->setIsPoisoned(true);
+
+  // Check that there is no paste (##) operator at the begining or end of the
+  // replacement list.
+  unsigned NumTokens = MI->getNumTokens();
+  if (NumTokens != 0) {
+    if (MI->getReplacementToken(0).is(tok::hashhash)) {
+      Diag(MI->getReplacementToken(0), diag::err_paste_at_start);
+      ReleaseMacroInfo(MI);
+      return;
+    }
+    if (MI->getReplacementToken(NumTokens-1).is(tok::hashhash)) {
+      Diag(MI->getReplacementToken(NumTokens-1), diag::err_paste_at_end);
+      ReleaseMacroInfo(MI);
+      return;
+    }
+  }
+
+  // If this is the primary source file, remember that this macro hasn't been
+  // used yet.
+  if (isInPrimaryFile())
+    MI->setIsUsed(false);
+
+  MI->setDefinitionEndLoc(LastTok.getLocation());
+
+  // Finally, if this identifier already had a macro defined for it, verify that
+  // the macro bodies are identical and free the old definition.
+  if (MacroInfo *OtherMI = getMacroInfo(MacroNameTok.getIdentifierInfo())) {
+    // It is very common for system headers to have tons of macro redefinitions
+    // and for warnings to be disabled in system headers.  If this is the case,
+    // then don't bother calling MacroInfo::isIdenticalTo.
+    if (!getDiagnostics().getSuppressSystemWarnings() ||
+        !SourceMgr.isInSystemHeader(DefineTok.getLocation())) {
+      if (!OtherMI->isUsed())
+        Diag(OtherMI->getDefinitionLoc(), diag::pp_macro_not_used);
+
+      // Macros must be identical.  This means all tokes and whitespace
+      // separation must be the same.  C99 6.10.3.2.
+      if (!MI->isIdenticalTo(*OtherMI, *this)) {
+        Diag(MI->getDefinitionLoc(), diag::ext_pp_macro_redef)
+          << MacroNameTok.getIdentifierInfo();
+        Diag(OtherMI->getDefinitionLoc(), diag::note_previous_definition);
+      }
+    }
+
+    ReleaseMacroInfo(OtherMI);
+  }
+
+  setMacroInfo(MacroNameTok.getIdentifierInfo(), MI);
+
+  // If the callbacks want to know, tell them about the macro definition.
+  if (Callbacks)
+    Callbacks->MacroDefined(MacroNameTok.getIdentifierInfo(), MI);
+}
+
+/// HandleUndefDirective - Implements #undef.
+///
+void Preprocessor::HandleUndefDirective(Token &UndefTok) {
+  ++NumUndefined;
+
+  Token MacroNameTok;
+  ReadMacroName(MacroNameTok, 2);
+
+  // Error reading macro name?  If so, diagnostic already issued.
+  if (MacroNameTok.is(tok::eom))
+    return;
+
+  // Check to see if this is the last token on the #undef line.
+  CheckEndOfDirective("undef");
+
+  // Okay, we finally have a valid identifier to undef.
+  MacroInfo *MI = getMacroInfo(MacroNameTok.getIdentifierInfo());
+
+  // If the macro is not defined, this is a noop undef, just return.
+  if (MI == 0) return;
+
+  if (!MI->isUsed())
+    Diag(MI->getDefinitionLoc(), diag::pp_macro_not_used);
+
+  // If the callbacks want to know, tell them about the macro #undef.
+  if (Callbacks)
+    Callbacks->MacroUndefined(MacroNameTok.getIdentifierInfo(), MI);
+
+  // Free macro definition.
+  ReleaseMacroInfo(MI);
+  setMacroInfo(MacroNameTok.getIdentifierInfo(), 0);
+}
+
+
+//===----------------------------------------------------------------------===//
+// Preprocessor Conditional Directive Handling.
+//===----------------------------------------------------------------------===//
+
+/// HandleIfdefDirective - Implements the #ifdef/#ifndef directive.  isIfndef is
+/// true when this is a #ifndef directive.  ReadAnyTokensBeforeDirective is true
+/// if any tokens have been returned or pp-directives activated before this
+/// #ifndef has been lexed.
+///
+void Preprocessor::HandleIfdefDirective(Token &Result, bool isIfndef,
+                                        bool ReadAnyTokensBeforeDirective) {
+  ++NumIf;
+  Token DirectiveTok = Result;
+
+  Token MacroNameTok;
+  ReadMacroName(MacroNameTok);
+
+  // Error reading macro name?  If so, diagnostic already issued.
+  if (MacroNameTok.is(tok::eom)) {
+    // Skip code until we get to #endif.  This helps with recovery by not
+    // emitting an error when the #endif is reached.
+    SkipExcludedConditionalBlock(DirectiveTok.getLocation(),
+                                 /*Foundnonskip*/false, /*FoundElse*/false);
+    return;
+  }
+
+  // Check to see if this is the last token on the #if[n]def line.
+  CheckEndOfDirective(isIfndef ? "ifndef" : "ifdef");
+
+  if (CurPPLexer->getConditionalStackDepth() == 0) {
+    // If the start of a top-level #ifdef, inform MIOpt.
+    if (!ReadAnyTokensBeforeDirective) {
+      assert(isIfndef && "#ifdef shouldn't reach here");
+      CurPPLexer->MIOpt.EnterTopLevelIFNDEF(MacroNameTok.getIdentifierInfo());
+    } else
+      CurPPLexer->MIOpt.EnterTopLevelConditional();
+  }
+
+  IdentifierInfo *MII = MacroNameTok.getIdentifierInfo();
+  MacroInfo *MI = getMacroInfo(MII);
+
+  // If there is a macro, process it.
+  if (MI)  // Mark it used.
+    MI->setIsUsed(true);
+
+  // Should we include the stuff contained by this directive?
+  if (!MI == isIfndef) {
+    // Yes, remember that we are inside a conditional, then lex the next token.
+    CurPPLexer->pushConditionalLevel(DirectiveTok.getLocation(),
+                                     /*wasskip*/false, /*foundnonskip*/true,
+                                     /*foundelse*/false);
+  } else {
+    // No, skip the contents of this block and return the first token after it.
+    SkipExcludedConditionalBlock(DirectiveTok.getLocation(),
+                                 /*Foundnonskip*/false,
+                                 /*FoundElse*/false);
+  }
+}
+
+/// HandleIfDirective - Implements the #if directive.
+///
+void Preprocessor::HandleIfDirective(Token &IfToken,
+                                     bool ReadAnyTokensBeforeDirective) {
+  ++NumIf;
+
+  // Parse and evaluation the conditional expression.
+  IdentifierInfo *IfNDefMacro = 0;
+  bool ConditionalTrue = EvaluateDirectiveExpression(IfNDefMacro);
+
+
+  // If this condition is equivalent to #ifndef X, and if this is the first
+  // directive seen, handle it for the multiple-include optimization.
+  if (CurPPLexer->getConditionalStackDepth() == 0) {
+    if (!ReadAnyTokensBeforeDirective && IfNDefMacro)
+      CurPPLexer->MIOpt.EnterTopLevelIFNDEF(IfNDefMacro);
+    else
+      CurPPLexer->MIOpt.EnterTopLevelConditional();
+  }
+
+  // Should we include the stuff contained by this directive?
+  if (ConditionalTrue) {
+    // Yes, remember that we are inside a conditional, then lex the next token.
+    CurPPLexer->pushConditionalLevel(IfToken.getLocation(), /*wasskip*/false,
+                                   /*foundnonskip*/true, /*foundelse*/false);
+  } else {
+    // No, skip the contents of this block and return the first token after it.
+    SkipExcludedConditionalBlock(IfToken.getLocation(), /*Foundnonskip*/false,
+                                 /*FoundElse*/false);
+  }
+}
+
+/// HandleEndifDirective - Implements the #endif directive.
+///
+void Preprocessor::HandleEndifDirective(Token &EndifToken) {
+  ++NumEndif;
+
+  // Check that this is the whole directive.
+  CheckEndOfDirective("endif");
+
+  PPConditionalInfo CondInfo;
+  if (CurPPLexer->popConditionalLevel(CondInfo)) {
+    // No conditionals on the stack: this is an #endif without an #if.
+    Diag(EndifToken, diag::err_pp_endif_without_if);
+    return;
+  }
+
+  // If this the end of a top-level #endif, inform MIOpt.
+  if (CurPPLexer->getConditionalStackDepth() == 0)
+    CurPPLexer->MIOpt.ExitTopLevelConditional();
+
+  assert(!CondInfo.WasSkipping && !CurPPLexer->LexingRawMode &&
+         "This code should only be reachable in the non-skipping case!");
+}
+
+
+void Preprocessor::HandleElseDirective(Token &Result) {
+  ++NumElse;
+
+  // #else directive in a non-skipping conditional... start skipping.
+  CheckEndOfDirective("else");
+
+  PPConditionalInfo CI;
+  if (CurPPLexer->popConditionalLevel(CI)) {
+    Diag(Result, diag::pp_err_else_without_if);
+    return;
+  }
+
+  // If this is a top-level #else, inform the MIOpt.
+  if (CurPPLexer->getConditionalStackDepth() == 0)
+    CurPPLexer->MIOpt.EnterTopLevelConditional();
+
+  // If this is a #else with a #else before it, report the error.
+  if (CI.FoundElse) Diag(Result, diag::pp_err_else_after_else);
+
+  // Finally, skip the rest of the contents of this block and return the first
+  // token after it.
+  return SkipExcludedConditionalBlock(CI.IfLoc, /*Foundnonskip*/true,
+                                      /*FoundElse*/true);
+}
+
+void Preprocessor::HandleElifDirective(Token &ElifToken) {
+  ++NumElse;
+
+  // #elif directive in a non-skipping conditional... start skipping.
+  // We don't care what the condition is, because we will always skip it (since
+  // the block immediately before it was included).
+  DiscardUntilEndOfDirective();
+
+  PPConditionalInfo CI;
+  if (CurPPLexer->popConditionalLevel(CI)) {
+    Diag(ElifToken, diag::pp_err_elif_without_if);
+    return;
+  }
+
+  // If this is a top-level #elif, inform the MIOpt.
+  if (CurPPLexer->getConditionalStackDepth() == 0)
+    CurPPLexer->MIOpt.EnterTopLevelConditional();
+
+  // If this is a #elif with a #else before it, report the error.
+  if (CI.FoundElse) Diag(ElifToken, diag::pp_err_elif_after_else);
+
+  // Finally, skip the rest of the contents of this block and return the first
+  // token after it.
+  return SkipExcludedConditionalBlock(CI.IfLoc, /*Foundnonskip*/true,
+                                      /*FoundElse*/CI.FoundElse);
+}
+