lib/Frontend/PrintPreprocessedOutput.cpp - platform/external/clang - Gitiles

 //===--- PrintPreprocessedOutput.cpp - Implement the -E mode --------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This code simply runs the preprocessor on the input file and prints out the
 // result.  This is the traditional behavior of the -E option.
 //
 //===----------------------------------------------------------------------===//

 #include "clang/Frontend/Utils.h"
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Frontend/PreprocessorOutputOptions.h"
 #include "clang/Lex/MacroInfo.h"
 #include "clang/Lex/PPCallbacks.h"
 #include "clang/Lex/Pragma.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Lex/TokenConcatenation.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cstdio>
 using namespace clang;

 /// PrintMacroDefinition - Print a macro definition in a form that will be
 /// properly accepted back as a definition.
 static void PrintMacroDefinition(const IdentifierInfo &II, const MacroInfo &MI,
                                  Preprocessor &PP, raw_ostream &OS) {
   OS << "#define " << II.getName();

   if (MI.isFunctionLike()) {
     OS << '(';
     if (!MI.arg_empty()) {
       MacroInfo::arg_iterator AI = MI.arg_begin(), E = MI.arg_end();
       for (; AI+1 != E; ++AI) {
         OS << (*AI)->getName();
         OS << ',';
       }

       // Last argument.
       if ((*AI)->getName() == "__VA_ARGS__")
         OS << "...";
       else
         OS << (*AI)->getName();
     }

     if (MI.isGNUVarargs())
       OS << "...";  // #define foo(x...)

     OS << ')';
   }

   // GCC always emits a space, even if the macro body is empty.  However, do not
   // want to emit two spaces if the first token has a leading space.
   if (MI.tokens_empty() || !MI.tokens_begin()->hasLeadingSpace())
     OS << ' ';

   SmallString<128> SpellingBuffer;
   for (MacroInfo::tokens_iterator I = MI.tokens_begin(), E = MI.tokens_end();
        I != E; ++I) {
     if (I->hasLeadingSpace())
       OS << ' ';

     OS << PP.getSpelling(*I, SpellingBuffer);
   }
 }

 //===----------------------------------------------------------------------===//
 // Preprocessed token printer
 //===----------------------------------------------------------------------===//

 namespace {
 class PrintPPOutputPPCallbacks : public PPCallbacks {
   Preprocessor &PP;
   SourceManager &SM;
   TokenConcatenation ConcatInfo;
 public:
   raw_ostream &OS;
 private:
   unsigned CurLine;

   bool EmittedTokensOnThisLine;
   bool EmittedDirectiveOnThisLine;
   SrcMgr::CharacteristicKind FileType;
   SmallString<512> CurFilename;
   bool Initialized;
   bool DisableLineMarkers;
   bool DumpDefines;
   bool UseLineDirective;
   bool IsFirstFileEntered;
 public:
   PrintPPOutputPPCallbacks(Preprocessor &pp, raw_ostream &os,
                            bool lineMarkers, bool defines)
      : PP(pp), SM(PP.getSourceManager()),
        ConcatInfo(PP), OS(os), DisableLineMarkers(lineMarkers),
        DumpDefines(defines) {
     CurLine = 0;
     CurFilename += "<uninit>";
     EmittedTokensOnThisLine = false;
     EmittedDirectiveOnThisLine = false;
     FileType = SrcMgr::C_User;
     Initialized = false;
     IsFirstFileEntered = false;

     // If we're in microsoft mode, use normal #line instead of line markers.
     UseLineDirective = PP.getLangOpts().MicrosoftExt;
   }

   void setEmittedTokensOnThisLine() { EmittedTokensOnThisLine = true; }
   bool hasEmittedTokensOnThisLine() const { return EmittedTokensOnThisLine; }

   void setEmittedDirectiveOnThisLine() { EmittedDirectiveOnThisLine = true; }
   bool hasEmittedDirectiveOnThisLine() const {
     return EmittedDirectiveOnThisLine;
   }

   bool startNewLineIfNeeded(bool ShouldUpdateCurrentLine = true);

   virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
                            SrcMgr::CharacteristicKind FileType,
                            FileID PrevFID);
   virtual void Ident(SourceLocation Loc, const std::string &str);
   virtual void PragmaComment(SourceLocation Loc, const IdentifierInfo *Kind,
                              const std::string &Str);
   virtual void PragmaMessage(SourceLocation Loc, StringRef Str);
   virtual void PragmaDiagnosticPush(SourceLocation Loc,
                                     StringRef Namespace);
   virtual void PragmaDiagnosticPop(SourceLocation Loc,
                                    StringRef Namespace);
   virtual void PragmaDiagnostic(SourceLocation Loc, StringRef Namespace,
                                 diag::Mapping Map, StringRef Str);

   bool HandleFirstTokOnLine(Token &Tok);

   /// Move to the line of the provided source location. This will
   /// return true if the output stream required adjustment or if
   /// the requested location is on the first line.
   bool MoveToLine(SourceLocation Loc) {
     PresumedLoc PLoc = SM.getPresumedLoc(Loc);
     if (PLoc.isInvalid())
       return false;
     return MoveToLine(PLoc.getLine()) || (PLoc.getLine() == 1);
   }
   bool MoveToLine(unsigned LineNo);

   bool AvoidConcat(const Token &PrevPrevTok, const Token &PrevTok,
                    const Token &Tok) {
     return ConcatInfo.AvoidConcat(PrevPrevTok, PrevTok, Tok);
   }
   void WriteLineInfo(unsigned LineNo, const char *Extra=0, unsigned ExtraLen=0);
   bool LineMarkersAreDisabled() const { return DisableLineMarkers; }
   void HandleNewlinesInToken(const char *TokStr, unsigned Len);

   /// MacroDefined - This hook is called whenever a macro definition is seen.
   void MacroDefined(const Token &MacroNameTok, const MacroDirective *MD);

   /// MacroUndefined - This hook is called whenever a macro #undef is seen.
   void MacroUndefined(const Token &MacroNameTok, const MacroDirective *MD);
 };
 }  // end anonymous namespace

 void PrintPPOutputPPCallbacks::WriteLineInfo(unsigned LineNo,
                                              const char *Extra,
                                              unsigned ExtraLen) {
   startNewLineIfNeeded(/*ShouldUpdateCurrentLine=*/false);

   // Emit #line directives or GNU line markers depending on what mode we're in.
   if (UseLineDirective) {
     OS << "#line" << ' ' << LineNo << ' ' << '"';
     OS.write(CurFilename.data(), CurFilename.size());
     OS << '"';
   } else {
     OS << '#' << ' ' << LineNo << ' ' << '"';
     OS.write(CurFilename.data(), CurFilename.size());
     OS << '"';

     if (ExtraLen)
       OS.write(Extra, ExtraLen);

     if (FileType == SrcMgr::C_System)
       OS.write(" 3", 2);
     else if (FileType == SrcMgr::C_ExternCSystem)
       OS.write(" 3 4", 4);
   }
   OS << '\n';
 }

 /// MoveToLine - Move the output to the source line specified by the location
 /// object.  We can do this by emitting some number of \n's, or be emitting a
 /// #line directive.  This returns false if already at the specified line, true
 /// if some newlines were emitted.
 bool PrintPPOutputPPCallbacks::MoveToLine(unsigned LineNo) {
   // If this line is "close enough" to the original line, just print newlines,
   // otherwise print a #line directive.
   if (LineNo-CurLine <= 8) {
     if (LineNo-CurLine == 1)
       OS << '\n';
     else if (LineNo == CurLine)
       return false;    // Spelling line moved, but expansion line didn't.
     else {
       const char *NewLines = "\n\n\n\n\n\n\n\n";
       OS.write(NewLines, LineNo-CurLine);
     }
   } else if (!DisableLineMarkers) {
     // Emit a #line or line marker.
     WriteLineInfo(LineNo, 0, 0);
   } else {
     // Okay, we're in -P mode, which turns off line markers.  However, we still
     // need to emit a newline between tokens on different lines.
     startNewLineIfNeeded(/*ShouldUpdateCurrentLine=*/false);
   }

   CurLine = LineNo;
   return true;
 }

 bool
 PrintPPOutputPPCallbacks::startNewLineIfNeeded(bool ShouldUpdateCurrentLine) {
   if (EmittedTokensOnThisLine || EmittedDirectiveOnThisLine) {
     OS << '\n';
     EmittedTokensOnThisLine = false;
     EmittedDirectiveOnThisLine = false;
     if (ShouldUpdateCurrentLine)
       ++CurLine;
     return true;
   }

   return false;
 }

 /// FileChanged - Whenever the preprocessor enters or exits a #include file
 /// it invokes this handler.  Update our conception of the current source
 /// position.
 void PrintPPOutputPPCallbacks::FileChanged(SourceLocation Loc,
                                            FileChangeReason Reason,
                                        SrcMgr::CharacteristicKind NewFileType,
                                        FileID PrevFID) {
   // Unless we are exiting a #include, make sure to skip ahead to the line the
   // #include directive was at.
   SourceManager &SourceMgr = SM;

   PresumedLoc UserLoc = SourceMgr.getPresumedLoc(Loc);
   if (UserLoc.isInvalid())
     return;

   unsigned NewLine = UserLoc.getLine();

   if (Reason == PPCallbacks::EnterFile) {
     SourceLocation IncludeLoc = UserLoc.getIncludeLoc();
     if (IncludeLoc.isValid())
       MoveToLine(IncludeLoc);
   } else if (Reason == PPCallbacks::SystemHeaderPragma) {
     MoveToLine(NewLine);

     // TODO GCC emits the # directive for this directive on the line AFTER the
     // directive and emits a bunch of spaces that aren't needed.  Emulate this
     // strange behavior.
   }

   CurLine = NewLine;

   CurFilename.clear();
   CurFilename += UserLoc.getFilename();
   Lexer::Stringify(CurFilename);
   FileType = NewFileType;

   if (DisableLineMarkers) {
     startNewLineIfNeeded(/*ShouldUpdateCurrentLine=*/false);
     return;
   }

   if (!Initialized) {
     WriteLineInfo(CurLine);
     Initialized = true;
   }

   // Do not emit an enter marker for the main file (which we expect is the first
   // entered file). This matches gcc, and improves compatibility with some tools
   // which track the # line markers as a way to determine when the preprocessed
   // output is in the context of the main file.
   if (Reason == PPCallbacks::EnterFile && !IsFirstFileEntered) {
     IsFirstFileEntered = true;
     return;
   }

   switch (Reason) {
   case PPCallbacks::EnterFile:
     WriteLineInfo(CurLine, " 1", 2);
     break;
   case PPCallbacks::ExitFile:
     WriteLineInfo(CurLine, " 2", 2);
     break;
   case PPCallbacks::SystemHeaderPragma:
   case PPCallbacks::RenameFile:
     WriteLineInfo(CurLine);
     break;
   }
 }

 /// Ident - Handle #ident directives when read by the preprocessor.
 ///
 void PrintPPOutputPPCallbacks::Ident(SourceLocation Loc, const std::string &S) {
   MoveToLine(Loc);

   OS.write("#ident ", strlen("#ident "));
   OS.write(&S[0], S.size());
   EmittedTokensOnThisLine = true;
 }

 /// MacroDefined - This hook is called whenever a macro definition is seen.
 void PrintPPOutputPPCallbacks::MacroDefined(const Token &MacroNameTok,
                                             const MacroDirective *MD) {
   const MacroInfo *MI = MD->getMacroInfo();
   // Only print out macro definitions in -dD mode.
   if (!DumpDefines ||
       // Ignore __FILE__ etc.
       MI->isBuiltinMacro()) return;

   MoveToLine(MI->getDefinitionLoc());
   PrintMacroDefinition(*MacroNameTok.getIdentifierInfo(), *MI, PP, OS);
   setEmittedDirectiveOnThisLine();
 }

 void PrintPPOutputPPCallbacks::MacroUndefined(const Token &MacroNameTok,
                                               const MacroDirective *MD) {
   // Only print out macro definitions in -dD mode.
   if (!DumpDefines) return;

   MoveToLine(MacroNameTok.getLocation());
   OS << "#undef " << MacroNameTok.getIdentifierInfo()->getName();
   setEmittedDirectiveOnThisLine();
 }

 void PrintPPOutputPPCallbacks::PragmaComment(SourceLocation Loc,
                                              const IdentifierInfo *Kind,
                                              const std::string &Str) {
   startNewLineIfNeeded();
   MoveToLine(Loc);
   OS << "#pragma comment(" << Kind->getName();

   if (!Str.empty()) {
     OS << ", \"";

     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
       unsigned char Char = Str[i];
       if (isPrintable(Char) && Char != '\\' && Char != '"')
         OS << (char)Char;
       else  // Output anything hard as an octal escape.
         OS << '\\'
            << (char)('0'+ ((Char >> 6) & 7))
            << (char)('0'+ ((Char >> 3) & 7))
            << (char)('0'+ ((Char >> 0) & 7));
     }
     OS << '"';
   }

   OS << ')';
   setEmittedDirectiveOnThisLine();
 }

 void PrintPPOutputPPCallbacks::PragmaMessage(SourceLocation Loc,
                                              StringRef Str) {
   startNewLineIfNeeded();
   MoveToLine(Loc);
   OS << "#pragma message(";

   OS << '"';

   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
     unsigned char Char = Str[i];
     if (isPrintable(Char) && Char != '\\' && Char != '"')
       OS << (char)Char;
     else  // Output anything hard as an octal escape.
       OS << '\\'
          << (char)('0'+ ((Char >> 6) & 7))
          << (char)('0'+ ((Char >> 3) & 7))
          << (char)('0'+ ((Char >> 0) & 7));
   }
   OS << '"';

   OS << ')';
   setEmittedDirectiveOnThisLine();
 }

 void PrintPPOutputPPCallbacks::
 PragmaDiagnosticPush(SourceLocation Loc, StringRef Namespace) {
   startNewLineIfNeeded();
   MoveToLine(Loc);
   OS << "#pragma " << Namespace << " diagnostic push";
   setEmittedDirectiveOnThisLine();
 }

 void PrintPPOutputPPCallbacks::
 PragmaDiagnosticPop(SourceLocation Loc, StringRef Namespace) {
   startNewLineIfNeeded();
   MoveToLine(Loc);
   OS << "#pragma " << Namespace << " diagnostic pop";
   setEmittedDirectiveOnThisLine();
 }

 void PrintPPOutputPPCallbacks::
 PragmaDiagnostic(SourceLocation Loc, StringRef Namespace,
                  diag::Mapping Map, StringRef Str) {
   startNewLineIfNeeded();
   MoveToLine(Loc);
   OS << "#pragma " << Namespace << " diagnostic ";
   switch (Map) {
   case diag::MAP_WARNING:
     OS << "warning";
     break;
   case diag::MAP_ERROR:
     OS << "error";
     break;
   case diag::MAP_IGNORE:
     OS << "ignored";
     break;
   case diag::MAP_FATAL:
     OS << "fatal";
     break;
   }
   OS << " \"" << Str << '"';
   setEmittedDirectiveOnThisLine();
 }

 /// HandleFirstTokOnLine - When emitting a preprocessed file in -E mode, this
 /// is called for the first token on each new line.  If this really is the start
 /// of a new logical line, handle it and return true, otherwise return false.
 /// This may not be the start of a logical line because the "start of line"
 /// marker is set for spelling lines, not expansion ones.
 bool PrintPPOutputPPCallbacks::HandleFirstTokOnLine(Token &Tok) {
   // Figure out what line we went to and insert the appropriate number of
   // newline characters.
   if (!MoveToLine(Tok.getLocation()))
     return false;

   // Print out space characters so that the first token on a line is
   // indented for easy reading.
   unsigned ColNo = SM.getExpansionColumnNumber(Tok.getLocation());

   // This hack prevents stuff like:
   // #define HASH #
   // HASH define foo bar
   // From having the # character end up at column 1, which makes it so it
   // is not handled as a #define next time through the preprocessor if in
   // -fpreprocessed mode.
   if (ColNo <= 1 && Tok.is(tok::hash))
     OS << ' ';

   // Otherwise, indent the appropriate number of spaces.
   for (; ColNo > 1; --ColNo)
     OS << ' ';

   return true;
 }

 void PrintPPOutputPPCallbacks::HandleNewlinesInToken(const char *TokStr,
                                                      unsigned Len) {
   unsigned NumNewlines = 0;
   for (; Len; --Len, ++TokStr) {
     if (*TokStr != '\n' &&
         *TokStr != '\r')
       continue;

     ++NumNewlines;

     // If we have \n\r or \r\n, skip both and count as one line.
     if (Len != 1 &&
         (TokStr[1] == '\n' || TokStr[1] == '\r') &&
         TokStr[0] != TokStr[1])
       ++TokStr, --Len;
   }

   if (NumNewlines == 0) return;

   CurLine += NumNewlines;
 }


 namespace {
 struct UnknownPragmaHandler : public PragmaHandler {
   const char *Prefix;
   PrintPPOutputPPCallbacks *Callbacks;

   UnknownPragmaHandler(const char *prefix, PrintPPOutputPPCallbacks *callbacks)
     : Prefix(prefix), Callbacks(callbacks) {}
   virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
                             Token &PragmaTok) {
     // Figure out what line we went to and insert the appropriate number of
     // newline characters.
     Callbacks->startNewLineIfNeeded();
     Callbacks->MoveToLine(PragmaTok.getLocation());
     Callbacks->OS.write(Prefix, strlen(Prefix));
     // Read and print all of the pragma tokens.
     while (PragmaTok.isNot(tok::eod)) {
       if (PragmaTok.hasLeadingSpace())
         Callbacks->OS << ' ';
       std::string TokSpell = PP.getSpelling(PragmaTok);
       Callbacks->OS.write(&TokSpell[0], TokSpell.size());
       PP.LexUnexpandedToken(PragmaTok);
     }
     Callbacks->setEmittedDirectiveOnThisLine();
   }
 };
 } // end anonymous namespace


 static void PrintPreprocessedTokens(Preprocessor &PP, Token &Tok,
                                     PrintPPOutputPPCallbacks *Callbacks,
                                     raw_ostream &OS) {
   bool DropComments = PP.getLangOpts().TraditionalCPP &&
                       !PP.getCommentRetentionState();

   char Buffer[256];
   Token PrevPrevTok, PrevTok;
   PrevPrevTok.startToken();
   PrevTok.startToken();
   while (1) {
     if (Callbacks->hasEmittedDirectiveOnThisLine()) {
       Callbacks->startNewLineIfNeeded();
       Callbacks->MoveToLine(Tok.getLocation());
     }

     // If this token is at the start of a line, emit newlines if needed.
     if (Tok.isAtStartOfLine() && Callbacks->HandleFirstTokOnLine(Tok)) {
       // done.
     } else if (Tok.hasLeadingSpace() ||
                // If we haven't emitted a token on this line yet, PrevTok isn't
                // useful to look at and no concatenation could happen anyway.
                (Callbacks->hasEmittedTokensOnThisLine() &&
                 // Don't print "-" next to "-", it would form "--".
                 Callbacks->AvoidConcat(PrevPrevTok, PrevTok, Tok))) {
       OS << ' ';
     }

     if (DropComments && Tok.is(tok::comment)) {
       // Skip comments. Normally the preprocessor does not generate
       // tok::comment nodes at all when not keeping comments, but under
       // -traditional-cpp the lexer keeps /all/ whitespace, including comments.
       SourceLocation StartLoc = Tok.getLocation();
       Callbacks->MoveToLine(StartLoc.getLocWithOffset(Tok.getLength()));
     } else if (IdentifierInfo *II = Tok.getIdentifierInfo()) {
       OS << II->getName();
     } else if (Tok.isLiteral() && !Tok.needsCleaning() &&
                Tok.getLiteralData()) {
       OS.write(Tok.getLiteralData(), Tok.getLength());
     } else if (Tok.getLength() < 256) {
       const char *TokPtr = Buffer;
       unsigned Len = PP.getSpelling(Tok, TokPtr);
       OS.write(TokPtr, Len);

       // Tokens that can contain embedded newlines need to adjust our current
       // line number.
       if (Tok.getKind() == tok::comment || Tok.getKind() == tok::unknown)
         Callbacks->HandleNewlinesInToken(TokPtr, Len);
     } else {
       std::string S = PP.getSpelling(Tok);
       OS.write(&S[0], S.size());

       // Tokens that can contain embedded newlines need to adjust our current
       // line number.
       if (Tok.getKind() == tok::comment || Tok.getKind() == tok::unknown)
         Callbacks->HandleNewlinesInToken(&S[0], S.size());
     }
     Callbacks->setEmittedTokensOnThisLine();

     if (Tok.is(tok::eof)) break;

     PrevPrevTok = PrevTok;
     PrevTok = Tok;
     PP.Lex(Tok);
   }
 }

 typedef std::pair<const IdentifierInfo *, MacroInfo *> id_macro_pair;
 static int MacroIDCompare(const void* a, const void* b) {
   const id_macro_pair *LHS = static_cast<const id_macro_pair*>(a);
   const id_macro_pair *RHS = static_cast<const id_macro_pair*>(b);
   return LHS->first->getName().compare(RHS->first->getName());
 }

 static void DoPrintMacros(Preprocessor &PP, raw_ostream *OS) {
   // Ignore unknown pragmas.
   PP.AddPragmaHandler(new EmptyPragmaHandler());

   // -dM mode just scans and ignores all tokens in the files, then dumps out
   // the macro table at the end.
   PP.EnterMainSourceFile();

   Token Tok;
   do PP.Lex(Tok);
   while (Tok.isNot(tok::eof));

   SmallVector<id_macro_pair, 128> MacrosByID;
   for (Preprocessor::macro_iterator I = PP.macro_begin(), E = PP.macro_end();
        I != E; ++I) {
     if (I->first->hasMacroDefinition())
       MacrosByID.push_back(id_macro_pair(I->first, I->second->getMacroInfo()));
   }
   llvm::array_pod_sort(MacrosByID.begin(), MacrosByID.end(), MacroIDCompare);

   for (unsigned i = 0, e = MacrosByID.size(); i != e; ++i) {
     MacroInfo &MI = *MacrosByID[i].second;
     // Ignore computed macros like __LINE__ and friends.
     if (MI.isBuiltinMacro()) continue;

     PrintMacroDefinition(*MacrosByID[i].first, MI, PP, *OS);
     *OS << '\n';
   }
 }

 /// DoPrintPreprocessedInput - This implements -E mode.
 ///
 void clang::DoPrintPreprocessedInput(Preprocessor &PP, raw_ostream *OS,
                                      const PreprocessorOutputOptions &Opts) {
   // Show macros with no output is handled specially.
   if (!Opts.ShowCPP) {
     assert(Opts.ShowMacros && "Not yet implemented!");
     DoPrintMacros(PP, OS);
     return;
   }

   // Inform the preprocessor whether we want it to retain comments or not, due
   // to -C or -CC.
   PP.SetCommentRetentionState(Opts.ShowComments, Opts.ShowMacroComments);

   PrintPPOutputPPCallbacks *Callbacks =
       new PrintPPOutputPPCallbacks(PP, *OS, !Opts.ShowLineMarkers,
                                    Opts.ShowMacros);
   PP.AddPragmaHandler(new UnknownPragmaHandler("#pragma", Callbacks));
   PP.AddPragmaHandler("GCC", new UnknownPragmaHandler("#pragma GCC",Callbacks));
   PP.AddPragmaHandler("clang",
                       new UnknownPragmaHandler("#pragma clang", Callbacks));

   PP.addPPCallbacks(Callbacks);

   // After we have configured the preprocessor, enter the main file.
   PP.EnterMainSourceFile();

   // Consume all of the tokens that come from the predefines buffer.  Those
   // should not be emitted into the output and are guaranteed to be at the
   // start.
   const SourceManager &SourceMgr = PP.getSourceManager();
   Token Tok;
   do {
     PP.Lex(Tok);
     if (Tok.is(tok::eof) || !Tok.getLocation().isFileID())
       break;

     PresumedLoc PLoc = SourceMgr.getPresumedLoc(Tok.getLocation());
     if (PLoc.isInvalid())
       break;

     if (strcmp(PLoc.getFilename(), "<built-in>"))
       break;
   } while (true);

   // Read all the preprocessed tokens, printing them out to the stream.
   PrintPreprocessedTokens(PP, Tok, Callbacks, *OS);
   *OS << '\n';
 }
	//===--- PrintPreprocessedOutput.cpp - Implement the -E mode --------------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This code simply runs the preprocessor on the input file and prints out the
	// result. This is the traditional behavior of the -E option.
	//
	//===----------------------------------------------------------------------===//

	#include "clang/Frontend/Utils.h"
	#include "clang/Basic/CharInfo.h"
	#include "clang/Basic/Diagnostic.h"
	#include "clang/Basic/SourceManager.h"
	#include "clang/Frontend/PreprocessorOutputOptions.h"
	#include "clang/Lex/MacroInfo.h"
	#include "clang/Lex/PPCallbacks.h"
	#include "clang/Lex/Pragma.h"
	#include "clang/Lex/Preprocessor.h"
	#include "clang/Lex/TokenConcatenation.h"
	#include "llvm/ADT/STLExtras.h"
	#include "llvm/ADT/SmallString.h"
	#include "llvm/ADT/StringRef.h"
	#include "llvm/Support/ErrorHandling.h"
	#include "llvm/Support/raw_ostream.h"
	#include <cstdio>
	using namespace clang;

	/// PrintMacroDefinition - Print a macro definition in a form that will be
	/// properly accepted back as a definition.
	static void PrintMacroDefinition(const IdentifierInfo &II, const MacroInfo &MI,
	Preprocessor &PP, raw_ostream &OS) {
	OS << "#define " << II.getName();

	if (MI.isFunctionLike()) {
	OS << '(';
	if (!MI.arg_empty()) {
	MacroInfo::arg_iterator AI = MI.arg_begin(), E = MI.arg_end();
	for (; AI+1 != E; ++AI) {
	OS << (*AI)->getName();
	OS << ',';
	}

	// Last argument.
	if ((*AI)->getName() == "__VA_ARGS__")
	OS << "...";
	else
	OS << (*AI)->getName();
	}

	if (MI.isGNUVarargs())
	OS << "..."; // #define foo(x...)

	OS << ')';
	}

	// GCC always emits a space, even if the macro body is empty. However, do not
	// want to emit two spaces if the first token has a leading space.
	if (MI.tokens_empty() \|\| !MI.tokens_begin()->hasLeadingSpace())
	OS << ' ';

	SmallString<128> SpellingBuffer;
	for (MacroInfo::tokens_iterator I = MI.tokens_begin(), E = MI.tokens_end();
	I != E; ++I) {
	if (I->hasLeadingSpace())
	OS << ' ';

	OS << PP.getSpelling(*I, SpellingBuffer);
	}
	}

	//===----------------------------------------------------------------------===//
	// Preprocessed token printer
	//===----------------------------------------------------------------------===//

	namespace {
	class PrintPPOutputPPCallbacks : public PPCallbacks {
	Preprocessor &PP;
	SourceManager &SM;
	TokenConcatenation ConcatInfo;
	public:
	raw_ostream &OS;
	private:
	unsigned CurLine;

	bool EmittedTokensOnThisLine;
	bool EmittedDirectiveOnThisLine;
	SrcMgr::CharacteristicKind FileType;
	SmallString<512> CurFilename;
	bool Initialized;
	bool DisableLineMarkers;
	bool DumpDefines;
	bool UseLineDirective;
	bool IsFirstFileEntered;
	public:
	PrintPPOutputPPCallbacks(Preprocessor &pp, raw_ostream &os,
	bool lineMarkers, bool defines)
	: PP(pp), SM(PP.getSourceManager()),
	ConcatInfo(PP), OS(os), DisableLineMarkers(lineMarkers),
	DumpDefines(defines) {
	CurLine = 0;
	CurFilename += "<uninit>";
	EmittedTokensOnThisLine = false;
	EmittedDirectiveOnThisLine = false;
	FileType = SrcMgr::C_User;
	Initialized = false;
	IsFirstFileEntered = false;

	// If we're in microsoft mode, use normal #line instead of line markers.
	UseLineDirective = PP.getLangOpts().MicrosoftExt;
	}

	void setEmittedTokensOnThisLine() { EmittedTokensOnThisLine = true; }
	bool hasEmittedTokensOnThisLine() const { return EmittedTokensOnThisLine; }

	void setEmittedDirectiveOnThisLine() { EmittedDirectiveOnThisLine = true; }
	bool hasEmittedDirectiveOnThisLine() const {
	return EmittedDirectiveOnThisLine;
	}

	bool startNewLineIfNeeded(bool ShouldUpdateCurrentLine = true);

	virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
	SrcMgr::CharacteristicKind FileType,
	FileID PrevFID);
	virtual void Ident(SourceLocation Loc, const std::string &str);
	virtual void PragmaComment(SourceLocation Loc, const IdentifierInfo *Kind,
	const std::string &Str);
	virtual void PragmaMessage(SourceLocation Loc, StringRef Str);
	virtual void PragmaDiagnosticPush(SourceLocation Loc,
	StringRef Namespace);
	virtual void PragmaDiagnosticPop(SourceLocation Loc,
	StringRef Namespace);
	virtual void PragmaDiagnostic(SourceLocation Loc, StringRef Namespace,
	diag::Mapping Map, StringRef Str);

	bool HandleFirstTokOnLine(Token &Tok);

	/// Move to the line of the provided source location. This will
	/// return true if the output stream required adjustment or if
	/// the requested location is on the first line.
	bool MoveToLine(SourceLocation Loc) {
	PresumedLoc PLoc = SM.getPresumedLoc(Loc);
	if (PLoc.isInvalid())
	return false;
	return MoveToLine(PLoc.getLine()) \|\| (PLoc.getLine() == 1);
	}
	bool MoveToLine(unsigned LineNo);

	bool AvoidConcat(const Token &PrevPrevTok, const Token &PrevTok,
	const Token &Tok) {
	return ConcatInfo.AvoidConcat(PrevPrevTok, PrevTok, Tok);
	}
	void WriteLineInfo(unsigned LineNo, const char *Extra=0, unsigned ExtraLen=0);
	bool LineMarkersAreDisabled() const { return DisableLineMarkers; }
	void HandleNewlinesInToken(const char *TokStr, unsigned Len);

	/// MacroDefined - This hook is called whenever a macro definition is seen.
	void MacroDefined(const Token &MacroNameTok, const MacroDirective *MD);

	/// MacroUndefined - This hook is called whenever a macro #undef is seen.
	void MacroUndefined(const Token &MacroNameTok, const MacroDirective *MD);
	};
	} // end anonymous namespace

	void PrintPPOutputPPCallbacks::WriteLineInfo(unsigned LineNo,
	const char *Extra,
	unsigned ExtraLen) {
	startNewLineIfNeeded(/ShouldUpdateCurrentLine=/false);

	// Emit #line directives or GNU line markers depending on what mode we're in.
	if (UseLineDirective) {
	OS << "#line" << ' ' << LineNo << ' ' << '"';
	OS.write(CurFilename.data(), CurFilename.size());
	OS << '"';
	} else {
	OS << '#' << ' ' << LineNo << ' ' << '"';
	OS.write(CurFilename.data(), CurFilename.size());
	OS << '"';

	if (ExtraLen)
	OS.write(Extra, ExtraLen);

	if (FileType == SrcMgr::C_System)
	OS.write(" 3", 2);
	else if (FileType == SrcMgr::C_ExternCSystem)
	OS.write(" 3 4", 4);
	}
	OS << '\n';
	}

	/// MoveToLine - Move the output to the source line specified by the location
	/// object. We can do this by emitting some number of \n's, or be emitting a
	/// #line directive. This returns false if already at the specified line, true
	/// if some newlines were emitted.
	bool PrintPPOutputPPCallbacks::MoveToLine(unsigned LineNo) {
	// If this line is "close enough" to the original line, just print newlines,
	// otherwise print a #line directive.
	if (LineNo-CurLine <= 8) {
	if (LineNo-CurLine == 1)
	OS << '\n';
	else if (LineNo == CurLine)
	return false; // Spelling line moved, but expansion line didn't.
	else {
	const char *NewLines = "\n\n\n\n\n\n\n\n";
	OS.write(NewLines, LineNo-CurLine);
	}
	} else if (!DisableLineMarkers) {
	// Emit a #line or line marker.
	WriteLineInfo(LineNo, 0, 0);
	} else {
	// Okay, we're in -P mode, which turns off line markers. However, we still
	// need to emit a newline between tokens on different lines.
	startNewLineIfNeeded(/ShouldUpdateCurrentLine=/false);
	}

	CurLine = LineNo;
	return true;
	}

	bool
	PrintPPOutputPPCallbacks::startNewLineIfNeeded(bool ShouldUpdateCurrentLine) {
	if (EmittedTokensOnThisLine \|\| EmittedDirectiveOnThisLine) {
	OS << '\n';
	EmittedTokensOnThisLine = false;
	EmittedDirectiveOnThisLine = false;
	if (ShouldUpdateCurrentLine)
	++CurLine;
	return true;
	}

	return false;
	}

	/// FileChanged - Whenever the preprocessor enters or exits a #include file
	/// it invokes this handler. Update our conception of the current source
	/// position.
	void PrintPPOutputPPCallbacks::FileChanged(SourceLocation Loc,
	FileChangeReason Reason,
	SrcMgr::CharacteristicKind NewFileType,
	FileID PrevFID) {
	// Unless we are exiting a #include, make sure to skip ahead to the line the
	// #include directive was at.
	SourceManager &SourceMgr = SM;

	PresumedLoc UserLoc = SourceMgr.getPresumedLoc(Loc);
	if (UserLoc.isInvalid())
	return;

	unsigned NewLine = UserLoc.getLine();

	if (Reason == PPCallbacks::EnterFile) {
	SourceLocation IncludeLoc = UserLoc.getIncludeLoc();
	if (IncludeLoc.isValid())
	MoveToLine(IncludeLoc);
	} else if (Reason == PPCallbacks::SystemHeaderPragma) {
	MoveToLine(NewLine);

	// TODO GCC emits the # directive for this directive on the line AFTER the
	// directive and emits a bunch of spaces that aren't needed. Emulate this
	// strange behavior.
	}

	CurLine = NewLine;

	CurFilename.clear();
	CurFilename += UserLoc.getFilename();
	Lexer::Stringify(CurFilename);
	FileType = NewFileType;

	if (DisableLineMarkers) {
	startNewLineIfNeeded(/ShouldUpdateCurrentLine=/false);
	return;
	}

	if (!Initialized) {
	WriteLineInfo(CurLine);
	Initialized = true;
	}

	// Do not emit an enter marker for the main file (which we expect is the first
	// entered file). This matches gcc, and improves compatibility with some tools
	// which track the # line markers as a way to determine when the preprocessed
	// output is in the context of the main file.
	if (Reason == PPCallbacks::EnterFile && !IsFirstFileEntered) {
	IsFirstFileEntered = true;
	return;
	}

	switch (Reason) {
	case PPCallbacks::EnterFile:
	WriteLineInfo(CurLine, " 1", 2);
	break;
	case PPCallbacks::ExitFile:
	WriteLineInfo(CurLine, " 2", 2);
	break;
	case PPCallbacks::SystemHeaderPragma:
	case PPCallbacks::RenameFile:
	WriteLineInfo(CurLine);
	break;
	}
	}

	/// Ident - Handle #ident directives when read by the preprocessor.
	///
	void PrintPPOutputPPCallbacks::Ident(SourceLocation Loc, const std::string &S) {
	MoveToLine(Loc);

	OS.write("#ident ", strlen("#ident "));
	OS.write(&S[0], S.size());
	EmittedTokensOnThisLine = true;
	}

	/// MacroDefined - This hook is called whenever a macro definition is seen.
	void PrintPPOutputPPCallbacks::MacroDefined(const Token &MacroNameTok,
	const MacroDirective *MD) {
	const MacroInfo *MI = MD->getMacroInfo();
	// Only print out macro definitions in -dD mode.
	if (!DumpDefines \|\|
	// Ignore __FILE__ etc.
	MI->isBuiltinMacro()) return;

	MoveToLine(MI->getDefinitionLoc());
	PrintMacroDefinition(MacroNameTok.getIdentifierInfo(), MI, PP, OS);
	setEmittedDirectiveOnThisLine();
	}

	void PrintPPOutputPPCallbacks::MacroUndefined(const Token &MacroNameTok,
	const MacroDirective *MD) {
	// Only print out macro definitions in -dD mode.
	if (!DumpDefines) return;

	MoveToLine(MacroNameTok.getLocation());
	OS << "#undef " << MacroNameTok.getIdentifierInfo()->getName();
	setEmittedDirectiveOnThisLine();
	}

	void PrintPPOutputPPCallbacks::PragmaComment(SourceLocation Loc,
	const IdentifierInfo *Kind,
	const std::string &Str) {
	startNewLineIfNeeded();
	MoveToLine(Loc);
	OS << "#pragma comment(" << Kind->getName();

	if (!Str.empty()) {
	OS << ", \"";

	for (unsigned i = 0, e = Str.size(); i != e; ++i) {
	unsigned char Char = Str[i];
	if (isPrintable(Char) && Char != '\\' && Char != '"')
	OS << (char)Char;
	else // Output anything hard as an octal escape.
	OS << '\\'
	<< (char)('0'+ ((Char >> 6) & 7))
	<< (char)('0'+ ((Char >> 3) & 7))
	<< (char)('0'+ ((Char >> 0) & 7));
	}
	OS << '"';
	}

	OS << ')';
	setEmittedDirectiveOnThisLine();
	}

	void PrintPPOutputPPCallbacks::PragmaMessage(SourceLocation Loc,
	StringRef Str) {
	startNewLineIfNeeded();
	MoveToLine(Loc);
	OS << "#pragma message(";

	OS << '"';

	for (unsigned i = 0, e = Str.size(); i != e; ++i) {
	unsigned char Char = Str[i];
	if (isPrintable(Char) && Char != '\\' && Char != '"')
	OS << (char)Char;
	else // Output anything hard as an octal escape.
	OS << '\\'
	<< (char)('0'+ ((Char >> 6) & 7))
	<< (char)('0'+ ((Char >> 3) & 7))
	<< (char)('0'+ ((Char >> 0) & 7));
	}
	OS << '"';

	OS << ')';
	setEmittedDirectiveOnThisLine();
	}

	void PrintPPOutputPPCallbacks::
	PragmaDiagnosticPush(SourceLocation Loc, StringRef Namespace) {
	startNewLineIfNeeded();
	MoveToLine(Loc);
	OS << "#pragma " << Namespace << " diagnostic push";
	setEmittedDirectiveOnThisLine();
	}

	void PrintPPOutputPPCallbacks::
	PragmaDiagnosticPop(SourceLocation Loc, StringRef Namespace) {
	startNewLineIfNeeded();
	MoveToLine(Loc);
	OS << "#pragma " << Namespace << " diagnostic pop";
	setEmittedDirectiveOnThisLine();
	}

	void PrintPPOutputPPCallbacks::
	PragmaDiagnostic(SourceLocation Loc, StringRef Namespace,
	diag::Mapping Map, StringRef Str) {
	startNewLineIfNeeded();
	MoveToLine(Loc);
	OS << "#pragma " << Namespace << " diagnostic ";
	switch (Map) {
	case diag::MAP_WARNING:
	OS << "warning";
	break;
	case diag::MAP_ERROR:
	OS << "error";
	break;
	case diag::MAP_IGNORE:
	OS << "ignored";
	break;
	case diag::MAP_FATAL:
	OS << "fatal";
	break;
	}
	OS << " \"" << Str << '"';
	setEmittedDirectiveOnThisLine();
	}

	/// HandleFirstTokOnLine - When emitting a preprocessed file in -E mode, this
	/// is called for the first token on each new line. If this really is the start
	/// of a new logical line, handle it and return true, otherwise return false.
	/// This may not be the start of a logical line because the "start of line"
	/// marker is set for spelling lines, not expansion ones.
	bool PrintPPOutputPPCallbacks::HandleFirstTokOnLine(Token &Tok) {
	// Figure out what line we went to and insert the appropriate number of
	// newline characters.
	if (!MoveToLine(Tok.getLocation()))
	return false;

	// Print out space characters so that the first token on a line is
	// indented for easy reading.
	unsigned ColNo = SM.getExpansionColumnNumber(Tok.getLocation());

	// This hack prevents stuff like:
	// #define HASH #
	// HASH define foo bar
	// From having the # character end up at column 1, which makes it so it
	// is not handled as a #define next time through the preprocessor if in
	// -fpreprocessed mode.
	if (ColNo <= 1 && Tok.is(tok::hash))
	OS << ' ';

	// Otherwise, indent the appropriate number of spaces.
	for (; ColNo > 1; --ColNo)
	OS << ' ';

	return true;
	}

	void PrintPPOutputPPCallbacks::HandleNewlinesInToken(const char *TokStr,
	unsigned Len) {
	unsigned NumNewlines = 0;
	for (; Len; --Len, ++TokStr) {
	if (*TokStr != '\n' &&
	*TokStr != '\r')
	continue;

	++NumNewlines;

	// If we have \n\r or \r\n, skip both and count as one line.
	if (Len != 1 &&
	(TokStr[1] == '\n' \|\| TokStr[1] == '\r') &&
	TokStr[0] != TokStr[1])
	++TokStr, --Len;
	}

	if (NumNewlines == 0) return;

	CurLine += NumNewlines;
	}


	namespace {
	struct UnknownPragmaHandler : public PragmaHandler {
	const char *Prefix;
	PrintPPOutputPPCallbacks *Callbacks;

	UnknownPragmaHandler(const char prefix, PrintPPOutputPPCallbacks callbacks)
	: Prefix(prefix), Callbacks(callbacks) {}
	virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
	Token &PragmaTok) {
	// Figure out what line we went to and insert the appropriate number of
	// newline characters.
	Callbacks->startNewLineIfNeeded();
	Callbacks->MoveToLine(PragmaTok.getLocation());
	Callbacks->OS.write(Prefix, strlen(Prefix));
	// Read and print all of the pragma tokens.
	while (PragmaTok.isNot(tok::eod)) {
	if (PragmaTok.hasLeadingSpace())
	Callbacks->OS << ' ';
	std::string TokSpell = PP.getSpelling(PragmaTok);
	Callbacks->OS.write(&TokSpell[0], TokSpell.size());
	PP.LexUnexpandedToken(PragmaTok);
	}
	Callbacks->setEmittedDirectiveOnThisLine();
	}
	};
	} // end anonymous namespace


	static void PrintPreprocessedTokens(Preprocessor &PP, Token &Tok,
	PrintPPOutputPPCallbacks *Callbacks,
	raw_ostream &OS) {
	bool DropComments = PP.getLangOpts().TraditionalCPP &&
	!PP.getCommentRetentionState();

	char Buffer[256];
	Token PrevPrevTok, PrevTok;
	PrevPrevTok.startToken();
	PrevTok.startToken();
	while (1) {
	if (Callbacks->hasEmittedDirectiveOnThisLine()) {
	Callbacks->startNewLineIfNeeded();
	Callbacks->MoveToLine(Tok.getLocation());
	}

	// If this token is at the start of a line, emit newlines if needed.
	if (Tok.isAtStartOfLine() && Callbacks->HandleFirstTokOnLine(Tok)) {
	// done.
	} else if (Tok.hasLeadingSpace() \|\|
	// If we haven't emitted a token on this line yet, PrevTok isn't
	// useful to look at and no concatenation could happen anyway.
	(Callbacks->hasEmittedTokensOnThisLine() &&
	// Don't print "-" next to "-", it would form "--".
	Callbacks->AvoidConcat(PrevPrevTok, PrevTok, Tok))) {
	OS << ' ';
	}

	if (DropComments && Tok.is(tok::comment)) {
	// Skip comments. Normally the preprocessor does not generate
	// tok::comment nodes at all when not keeping comments, but under
	// -traditional-cpp the lexer keeps /all/ whitespace, including comments.
	SourceLocation StartLoc = Tok.getLocation();
	Callbacks->MoveToLine(StartLoc.getLocWithOffset(Tok.getLength()));
	} else if (IdentifierInfo *II = Tok.getIdentifierInfo()) {
	OS << II->getName();
	} else if (Tok.isLiteral() && !Tok.needsCleaning() &&
	Tok.getLiteralData()) {
	OS.write(Tok.getLiteralData(), Tok.getLength());
	} else if (Tok.getLength() < 256) {
	const char *TokPtr = Buffer;
	unsigned Len = PP.getSpelling(Tok, TokPtr);
	OS.write(TokPtr, Len);

	// Tokens that can contain embedded newlines need to adjust our current
	// line number.
	if (Tok.getKind() == tok::comment \|\| Tok.getKind() == tok::unknown)
	Callbacks->HandleNewlinesInToken(TokPtr, Len);
	} else {
	std::string S = PP.getSpelling(Tok);
	OS.write(&S[0], S.size());

	// Tokens that can contain embedded newlines need to adjust our current
	// line number.
	if (Tok.getKind() == tok::comment \|\| Tok.getKind() == tok::unknown)
	Callbacks->HandleNewlinesInToken(&S[0], S.size());
	}
	Callbacks->setEmittedTokensOnThisLine();

	if (Tok.is(tok::eof)) break;

	PrevPrevTok = PrevTok;
	PrevTok = Tok;
	PP.Lex(Tok);
	}
	}

	typedef std::pair<const IdentifierInfo , MacroInfo > id_macro_pair;
	static int MacroIDCompare(const void* a, const void* b) {
	const id_macro_pair LHS = static_cast<const id_macro_pair>(a);
	const id_macro_pair RHS = static_cast<const id_macro_pair>(b);
	return LHS->first->getName().compare(RHS->first->getName());
	}

	static void DoPrintMacros(Preprocessor &PP, raw_ostream *OS) {
	// Ignore unknown pragmas.
	PP.AddPragmaHandler(new EmptyPragmaHandler());

	// -dM mode just scans and ignores all tokens in the files, then dumps out
	// the macro table at the end.
	PP.EnterMainSourceFile();

	Token Tok;
	do PP.Lex(Tok);
	while (Tok.isNot(tok::eof));

	SmallVector<id_macro_pair, 128> MacrosByID;
	for (Preprocessor::macro_iterator I = PP.macro_begin(), E = PP.macro_end();
	I != E; ++I) {
	if (I->first->hasMacroDefinition())
	MacrosByID.push_back(id_macro_pair(I->first, I->second->getMacroInfo()));
	}
	llvm::array_pod_sort(MacrosByID.begin(), MacrosByID.end(), MacroIDCompare);

	for (unsigned i = 0, e = MacrosByID.size(); i != e; ++i) {
	MacroInfo &MI = *MacrosByID[i].second;
	// Ignore computed macros like __LINE__ and friends.
	if (MI.isBuiltinMacro()) continue;

	PrintMacroDefinition(MacrosByID[i].first, MI, PP, OS);
	*OS << '\n';
	}
	}

	/// DoPrintPreprocessedInput - This implements -E mode.
	///
	void clang::DoPrintPreprocessedInput(Preprocessor &PP, raw_ostream *OS,
	const PreprocessorOutputOptions &Opts) {
	// Show macros with no output is handled specially.
	if (!Opts.ShowCPP) {
	assert(Opts.ShowMacros && "Not yet implemented!");
	DoPrintMacros(PP, OS);
	return;
	}

	// Inform the preprocessor whether we want it to retain comments or not, due
	// to -C or -CC.
	PP.SetCommentRetentionState(Opts.ShowComments, Opts.ShowMacroComments);

	PrintPPOutputPPCallbacks *Callbacks =
	new PrintPPOutputPPCallbacks(PP, *OS, !Opts.ShowLineMarkers,
	Opts.ShowMacros);
	PP.AddPragmaHandler(new UnknownPragmaHandler("#pragma", Callbacks));
	PP.AddPragmaHandler("GCC", new UnknownPragmaHandler("#pragma GCC",Callbacks));
	PP.AddPragmaHandler("clang",
	new UnknownPragmaHandler("#pragma clang", Callbacks));

	PP.addPPCallbacks(Callbacks);

	// After we have configured the preprocessor, enter the main file.
	PP.EnterMainSourceFile();

	// Consume all of the tokens that come from the predefines buffer. Those
	// should not be emitted into the output and are guaranteed to be at the
	// start.
	const SourceManager &SourceMgr = PP.getSourceManager();
	Token Tok;
	do {
	PP.Lex(Tok);
	if (Tok.is(tok::eof) \|\| !Tok.getLocation().isFileID())
	break;

	PresumedLoc PLoc = SourceMgr.getPresumedLoc(Tok.getLocation());
	if (PLoc.isInvalid())
	break;

	if (strcmp(PLoc.getFilename(), "<built-in>"))
	break;
	} while (true);

	// Read all the preprocessed tokens, printing them out to the stream.
	PrintPreprocessedTokens(PP, Tok, Callbacks, *OS);
	*OS << '\n';
	}