1 //===--- PrintPreprocessedOutput.cpp - Implement the -E mode --------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This code simply runs the preprocessor on the input file and prints out the
11 // result.  This is the traditional behavior of the -E option.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/Frontend/Utils.h"
16 #include "clang/Basic/Diagnostic.h"
17 #include "clang/Basic/SourceManager.h"
18 #include "clang/Frontend/PreprocessorOutputOptions.h"
19 #include "clang/Lex/MacroInfo.h"
20 #include "clang/Lex/PPCallbacks.h"
21 #include "clang/Lex/Pragma.h"
22 #include "clang/Lex/Preprocessor.h"
23 #include "clang/Lex/TokenConcatenation.h"
24 #include "llvm/ADT/SmallString.h"
25 #include "llvm/ADT/STLExtras.h"
26 #include "llvm/ADT/StringRef.h"
27 #include "llvm/Support/raw_ostream.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include <cstdio>
30 using namespace clang;
31 
32 /// PrintMacroDefinition - Print a macro definition in a form that will be
33 /// properly accepted back as a definition.
34 static void PrintMacroDefinition(const IdentifierInfo &II, const MacroInfo &MI,
35                                  Preprocessor &PP, raw_ostream &OS) {
36   OS << "#define " << II.getName();
37 
38   if (MI.isFunctionLike()) {
39     OS << '(';
40     if (!MI.arg_empty()) {
41       MacroInfo::arg_iterator AI = MI.arg_begin(), E = MI.arg_end();
42       for (; AI+1 != E; ++AI) {
43         OS << (*AI)->getName();
44         OS << ',';
45       }
46 
47       // Last argument.
48       if ((*AI)->getName() == "__VA_ARGS__")
49         OS << "...";
50       else
51         OS << (*AI)->getName();
52     }
53 
54     if (MI.isGNUVarargs())
55       OS << "...";  // #define foo(x...)
56 
57     OS << ')';
58   }
59 
60   // GCC always emits a space, even if the macro body is empty.  However, do not
61   // want to emit two spaces if the first token has a leading space.
62   if (MI.tokens_empty() || !MI.tokens_begin()->hasLeadingSpace())
63     OS << ' ';
64 
65   llvm::SmallString<128> SpellingBuffer;
66   for (MacroInfo::tokens_iterator I = MI.tokens_begin(), E = MI.tokens_end();
67        I != E; ++I) {
68     if (I->hasLeadingSpace())
69       OS << ' ';
70 
71     OS << PP.getSpelling(*I, SpellingBuffer);
72   }
73 }
74 
75 //===----------------------------------------------------------------------===//
76 // Preprocessed token printer
77 //===----------------------------------------------------------------------===//
78 
79 namespace {
80 class PrintPPOutputPPCallbacks : public PPCallbacks {
81   Preprocessor &PP;
82   SourceManager &SM;
83   TokenConcatenation ConcatInfo;
84 public:
85   raw_ostream &OS;
86 private:
87   unsigned CurLine;
88 
89   bool EmittedTokensOnThisLine;
90   bool EmittedMacroOnThisLine;
91   SrcMgr::CharacteristicKind FileType;
92   llvm::SmallString<512> CurFilename;
93   bool Initialized;
94   bool DisableLineMarkers;
95   bool DumpDefines;
96   bool UseLineDirective;
97 public:
98   PrintPPOutputPPCallbacks(Preprocessor &pp, raw_ostream &os,
99                            bool lineMarkers, bool defines)
100      : PP(pp), SM(PP.getSourceManager()),
101        ConcatInfo(PP), OS(os), DisableLineMarkers(lineMarkers),
102        DumpDefines(defines) {
103     CurLine = 0;
104     CurFilename += "<uninit>";
105     EmittedTokensOnThisLine = false;
106     EmittedMacroOnThisLine = false;
107     FileType = SrcMgr::C_User;
108     Initialized = false;
109 
110     // If we're in microsoft mode, use normal #line instead of line markers.
111     UseLineDirective = PP.getLangOptions().MicrosoftExt;
112   }
113 
114   void SetEmittedTokensOnThisLine() { EmittedTokensOnThisLine = true; }
115   bool hasEmittedTokensOnThisLine() const { return EmittedTokensOnThisLine; }
116 
117   bool StartNewLineIfNeeded();
118 
119   virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
120                            SrcMgr::CharacteristicKind FileType,
121                            FileID PrevFID);
122   virtual void Ident(SourceLocation Loc, const std::string &str);
123   virtual void PragmaComment(SourceLocation Loc, const IdentifierInfo *Kind,
124                              const std::string &Str);
125   virtual void PragmaMessage(SourceLocation Loc, StringRef Str);
126   virtual void PragmaDiagnosticPush(SourceLocation Loc,
127                                     StringRef Namespace);
128   virtual void PragmaDiagnosticPop(SourceLocation Loc,
129                                    StringRef Namespace);
130   virtual void PragmaDiagnostic(SourceLocation Loc, StringRef Namespace,
131                                 diag::Mapping Map, StringRef Str);
132 
133   bool HandleFirstTokOnLine(Token &Tok);
134   bool MoveToLine(SourceLocation Loc) {
135     PresumedLoc PLoc = SM.getPresumedLoc(Loc);
136     if (PLoc.isInvalid())
137       return false;
138     return MoveToLine(PLoc.getLine());
139   }
140   bool MoveToLine(unsigned LineNo);
141 
142   bool AvoidConcat(const Token &PrevPrevTok, const Token &PrevTok,
143                    const Token &Tok) {
144     return ConcatInfo.AvoidConcat(PrevPrevTok, PrevTok, Tok);
145   }
146   void WriteLineInfo(unsigned LineNo, const char *Extra=0, unsigned ExtraLen=0);
147   bool LineMarkersAreDisabled() const { return DisableLineMarkers; }
148   void HandleNewlinesInToken(const char *TokStr, unsigned Len);
149 
150   /// MacroDefined - This hook is called whenever a macro definition is seen.
151   void MacroDefined(const Token &MacroNameTok, const MacroInfo *MI);
152 
153   /// MacroUndefined - This hook is called whenever a macro #undef is seen.
154   void MacroUndefined(const Token &MacroNameTok, const MacroInfo *MI);
155 };
156 }  // end anonymous namespace
157 
158 void PrintPPOutputPPCallbacks::WriteLineInfo(unsigned LineNo,
159                                              const char *Extra,
160                                              unsigned ExtraLen) {
161   if (EmittedTokensOnThisLine || EmittedMacroOnThisLine) {
162     OS << '\n';
163     EmittedTokensOnThisLine = false;
164     EmittedMacroOnThisLine = false;
165   }
166 
167   // Emit #line directives or GNU line markers depending on what mode we're in.
168   if (UseLineDirective) {
169     OS << "#line" << ' ' << LineNo << ' ' << '"';
170     OS.write(CurFilename.data(), CurFilename.size());
171     OS << '"';
172   } else {
173     OS << '#' << ' ' << LineNo << ' ' << '"';
174     OS.write(CurFilename.data(), CurFilename.size());
175     OS << '"';
176 
177     if (ExtraLen)
178       OS.write(Extra, ExtraLen);
179 
180     if (FileType == SrcMgr::C_System)
181       OS.write(" 3", 2);
182     else if (FileType == SrcMgr::C_ExternCSystem)
183       OS.write(" 3 4", 4);
184   }
185   OS << '\n';
186 }
187 
188 /// MoveToLine - Move the output to the source line specified by the location
189 /// object.  We can do this by emitting some number of \n's, or be emitting a
190 /// #line directive.  This returns false if already at the specified line, true
191 /// if some newlines were emitted.
192 bool PrintPPOutputPPCallbacks::MoveToLine(unsigned LineNo) {
193   // If this line is "close enough" to the original line, just print newlines,
194   // otherwise print a #line directive.
195   if (LineNo-CurLine <= 8) {
196     if (LineNo-CurLine == 1)
197       OS << '\n';
198     else if (LineNo == CurLine)
199       return false;    // Spelling line moved, but expansion line didn't.
200     else {
201       const char *NewLines = "\n\n\n\n\n\n\n\n";
202       OS.write(NewLines, LineNo-CurLine);
203     }
204   } else if (!DisableLineMarkers) {
205     // Emit a #line or line marker.
206     WriteLineInfo(LineNo, 0, 0);
207   } else {
208     // Okay, we're in -P mode, which turns off line markers.  However, we still
209     // need to emit a newline between tokens on different lines.
210     if (EmittedTokensOnThisLine || EmittedMacroOnThisLine) {
211       OS << '\n';
212       EmittedTokensOnThisLine = false;
213       EmittedMacroOnThisLine = false;
214     }
215   }
216 
217   CurLine = LineNo;
218   return true;
219 }
220 
221 bool PrintPPOutputPPCallbacks::StartNewLineIfNeeded() {
222   if (EmittedTokensOnThisLine || EmittedMacroOnThisLine) {
223     OS << '\n';
224     EmittedTokensOnThisLine = false;
225     EmittedMacroOnThisLine = false;
226     ++CurLine;
227     return true;
228   }
229 
230   return false;
231 }
232 
233 /// FileChanged - Whenever the preprocessor enters or exits a #include file
234 /// it invokes this handler.  Update our conception of the current source
235 /// position.
236 void PrintPPOutputPPCallbacks::FileChanged(SourceLocation Loc,
237                                            FileChangeReason Reason,
238                                        SrcMgr::CharacteristicKind NewFileType,
239                                        FileID PrevFID) {
240   // Unless we are exiting a #include, make sure to skip ahead to the line the
241   // #include directive was at.
242   SourceManager &SourceMgr = SM;
243 
244   PresumedLoc UserLoc = SourceMgr.getPresumedLoc(Loc);
245   if (UserLoc.isInvalid())
246     return;
247 
248   unsigned NewLine = UserLoc.getLine();
249 
250   if (Reason == PPCallbacks::EnterFile) {
251     SourceLocation IncludeLoc = UserLoc.getIncludeLoc();
252     if (IncludeLoc.isValid())
253       MoveToLine(IncludeLoc);
254   } else if (Reason == PPCallbacks::SystemHeaderPragma) {
255     MoveToLine(NewLine);
256 
257     // TODO GCC emits the # directive for this directive on the line AFTER the
258     // directive and emits a bunch of spaces that aren't needed.  Emulate this
259     // strange behavior.
260   }
261 
262   CurLine = NewLine;
263 
264   CurFilename.clear();
265   CurFilename += UserLoc.getFilename();
266   Lexer::Stringify(CurFilename);
267   FileType = NewFileType;
268 
269   if (DisableLineMarkers) return;
270 
271   if (!Initialized) {
272     WriteLineInfo(CurLine);
273     Initialized = true;
274   }
275 
276   switch (Reason) {
277   case PPCallbacks::EnterFile:
278     WriteLineInfo(CurLine, " 1", 2);
279     break;
280   case PPCallbacks::ExitFile:
281     WriteLineInfo(CurLine, " 2", 2);
282     break;
283   case PPCallbacks::SystemHeaderPragma:
284   case PPCallbacks::RenameFile:
285     WriteLineInfo(CurLine);
286     break;
287   }
288 }
289 
290 /// Ident - Handle #ident directives when read by the preprocessor.
291 ///
292 void PrintPPOutputPPCallbacks::Ident(SourceLocation Loc, const std::string &S) {
293   MoveToLine(Loc);
294 
295   OS.write("#ident ", strlen("#ident "));
296   OS.write(&S[0], S.size());
297   EmittedTokensOnThisLine = true;
298 }
299 
300 /// MacroDefined - This hook is called whenever a macro definition is seen.
301 void PrintPPOutputPPCallbacks::MacroDefined(const Token &MacroNameTok,
302                                             const MacroInfo *MI) {
303   // Only print out macro definitions in -dD mode.
304   if (!DumpDefines ||
305       // Ignore __FILE__ etc.
306       MI->isBuiltinMacro()) return;
307 
308   MoveToLine(MI->getDefinitionLoc());
309   PrintMacroDefinition(*MacroNameTok.getIdentifierInfo(), *MI, PP, OS);
310   EmittedMacroOnThisLine = true;
311 }
312 
313 void PrintPPOutputPPCallbacks::MacroUndefined(const Token &MacroNameTok,
314                                               const MacroInfo *MI) {
315   // Only print out macro definitions in -dD mode.
316   if (!DumpDefines) return;
317 
318   MoveToLine(MacroNameTok.getLocation());
319   OS << "#undef " << MacroNameTok.getIdentifierInfo()->getName();
320   EmittedMacroOnThisLine = true;
321 }
322 
323 void PrintPPOutputPPCallbacks::PragmaComment(SourceLocation Loc,
324                                              const IdentifierInfo *Kind,
325                                              const std::string &Str) {
326   MoveToLine(Loc);
327   OS << "#pragma comment(" << Kind->getName();
328 
329   if (!Str.empty()) {
330     OS << ", \"";
331 
332     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
333       unsigned char Char = Str[i];
334       if (isprint(Char) && Char != '\\' && Char != '"')
335         OS << (char)Char;
336       else  // Output anything hard as an octal escape.
337         OS << '\\'
338            << (char)('0'+ ((Char >> 6) & 7))
339            << (char)('0'+ ((Char >> 3) & 7))
340            << (char)('0'+ ((Char >> 0) & 7));
341     }
342     OS << '"';
343   }
344 
345   OS << ')';
346   EmittedTokensOnThisLine = true;
347 }
348 
349 void PrintPPOutputPPCallbacks::PragmaMessage(SourceLocation Loc,
350                                              StringRef Str) {
351   MoveToLine(Loc);
352   OS << "#pragma message(";
353 
354   OS << '"';
355 
356   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
357     unsigned char Char = Str[i];
358     if (isprint(Char) && Char != '\\' && Char != '"')
359       OS << (char)Char;
360     else  // Output anything hard as an octal escape.
361       OS << '\\'
362          << (char)('0'+ ((Char >> 6) & 7))
363          << (char)('0'+ ((Char >> 3) & 7))
364          << (char)('0'+ ((Char >> 0) & 7));
365   }
366   OS << '"';
367 
368   OS << ')';
369   EmittedTokensOnThisLine = true;
370 }
371 
372 void PrintPPOutputPPCallbacks::
373 PragmaDiagnosticPush(SourceLocation Loc, StringRef Namespace) {
374   MoveToLine(Loc);
375   OS << "#pragma " << Namespace << " diagnostic push";
376   EmittedTokensOnThisLine = true;
377 }
378 
379 void PrintPPOutputPPCallbacks::
380 PragmaDiagnosticPop(SourceLocation Loc, StringRef Namespace) {
381   MoveToLine(Loc);
382   OS << "#pragma " << Namespace << " diagnostic pop";
383   EmittedTokensOnThisLine = true;
384 }
385 
386 void PrintPPOutputPPCallbacks::
387 PragmaDiagnostic(SourceLocation Loc, StringRef Namespace,
388                  diag::Mapping Map, StringRef Str) {
389   MoveToLine(Loc);
390   OS << "#pragma " << Namespace << " diagnostic ";
391   switch (Map) {
392   default: llvm_unreachable("unexpected diagnostic kind");
393   case diag::MAP_WARNING:
394     OS << "warning";
395     break;
396   case diag::MAP_ERROR:
397     OS << "error";
398     break;
399   case diag::MAP_IGNORE:
400     OS << "ignored";
401     break;
402   case diag::MAP_FATAL:
403     OS << "fatal";
404     break;
405   }
406   OS << " \"" << Str << '"';
407   EmittedTokensOnThisLine = true;
408 }
409 
410 /// HandleFirstTokOnLine - When emitting a preprocessed file in -E mode, this
411 /// is called for the first token on each new line.  If this really is the start
412 /// of a new logical line, handle it and return true, otherwise return false.
413 /// This may not be the start of a logical line because the "start of line"
414 /// marker is set for spelling lines, not expansion ones.
415 bool PrintPPOutputPPCallbacks::HandleFirstTokOnLine(Token &Tok) {
416   // Figure out what line we went to and insert the appropriate number of
417   // newline characters.
418   if (!MoveToLine(Tok.getLocation()))
419     return false;
420 
421   // Print out space characters so that the first token on a line is
422   // indented for easy reading.
423   unsigned ColNo = SM.getExpansionColumnNumber(Tok.getLocation());
424 
425   // This hack prevents stuff like:
426   // #define HASH #
427   // HASH define foo bar
428   // From having the # character end up at column 1, which makes it so it
429   // is not handled as a #define next time through the preprocessor if in
430   // -fpreprocessed mode.
431   if (ColNo <= 1 && Tok.is(tok::hash))
432     OS << ' ';
433 
434   // Otherwise, indent the appropriate number of spaces.
435   for (; ColNo > 1; --ColNo)
436     OS << ' ';
437 
438   return true;
439 }
440 
441 void PrintPPOutputPPCallbacks::HandleNewlinesInToken(const char *TokStr,
442                                                      unsigned Len) {
443   unsigned NumNewlines = 0;
444   for (; Len; --Len, ++TokStr) {
445     if (*TokStr != '\n' &&
446         *TokStr != '\r')
447       continue;
448 
449     ++NumNewlines;
450 
451     // If we have \n\r or \r\n, skip both and count as one line.
452     if (Len != 1 &&
453         (TokStr[1] == '\n' || TokStr[1] == '\r') &&
454         TokStr[0] != TokStr[1])
455       ++TokStr, --Len;
456   }
457 
458   if (NumNewlines == 0) return;
459 
460   CurLine += NumNewlines;
461 }
462 
463 
464 namespace {
465 struct UnknownPragmaHandler : public PragmaHandler {
466   const char *Prefix;
467   PrintPPOutputPPCallbacks *Callbacks;
468 
469   UnknownPragmaHandler(const char *prefix, PrintPPOutputPPCallbacks *callbacks)
470     : Prefix(prefix), Callbacks(callbacks) {}
471   virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
472                             Token &PragmaTok) {
473     // Figure out what line we went to and insert the appropriate number of
474     // newline characters.
475     Callbacks->StartNewLineIfNeeded();
476     Callbacks->MoveToLine(PragmaTok.getLocation());
477     Callbacks->OS.write(Prefix, strlen(Prefix));
478     Callbacks->SetEmittedTokensOnThisLine();
479     // Read and print all of the pragma tokens.
480     while (PragmaTok.isNot(tok::eod)) {
481       if (PragmaTok.hasLeadingSpace())
482         Callbacks->OS << ' ';
483       std::string TokSpell = PP.getSpelling(PragmaTok);
484       Callbacks->OS.write(&TokSpell[0], TokSpell.size());
485       PP.LexUnexpandedToken(PragmaTok);
486     }
487     Callbacks->StartNewLineIfNeeded();
488   }
489 };
490 } // end anonymous namespace
491 
492 
493 static void PrintPreprocessedTokens(Preprocessor &PP, Token &Tok,
494                                     PrintPPOutputPPCallbacks *Callbacks,
495                                     raw_ostream &OS) {
496   char Buffer[256];
497   Token PrevPrevTok, PrevTok;
498   PrevPrevTok.startToken();
499   PrevTok.startToken();
500   while (1) {
501 
502     // If this token is at the start of a line, emit newlines if needed.
503     if (Tok.isAtStartOfLine() && Callbacks->HandleFirstTokOnLine(Tok)) {
504       // done.
505     } else if (Tok.hasLeadingSpace() ||
506                // If we haven't emitted a token on this line yet, PrevTok isn't
507                // useful to look at and no concatenation could happen anyway.
508                (Callbacks->hasEmittedTokensOnThisLine() &&
509                 // Don't print "-" next to "-", it would form "--".
510                 Callbacks->AvoidConcat(PrevPrevTok, PrevTok, Tok))) {
511       OS << ' ';
512     }
513 
514     if (IdentifierInfo *II = Tok.getIdentifierInfo()) {
515       OS << II->getName();
516     } else if (Tok.isLiteral() && !Tok.needsCleaning() &&
517                Tok.getLiteralData()) {
518       OS.write(Tok.getLiteralData(), Tok.getLength());
519     } else if (Tok.getLength() < 256) {
520       const char *TokPtr = Buffer;
521       unsigned Len = PP.getSpelling(Tok, TokPtr);
522       OS.write(TokPtr, Len);
523 
524       // Tokens that can contain embedded newlines need to adjust our current
525       // line number.
526       if (Tok.getKind() == tok::comment)
527         Callbacks->HandleNewlinesInToken(TokPtr, Len);
528     } else {
529       std::string S = PP.getSpelling(Tok);
530       OS.write(&S[0], S.size());
531 
532       // Tokens that can contain embedded newlines need to adjust our current
533       // line number.
534       if (Tok.getKind() == tok::comment)
535         Callbacks->HandleNewlinesInToken(&S[0], S.size());
536     }
537     Callbacks->SetEmittedTokensOnThisLine();
538 
539     if (Tok.is(tok::eof)) break;
540 
541     PrevPrevTok = PrevTok;
542     PrevTok = Tok;
543     PP.Lex(Tok);
544   }
545 }
546 
547 typedef std::pair<IdentifierInfo*, MacroInfo*> id_macro_pair;
548 static int MacroIDCompare(const void* a, const void* b) {
549   const id_macro_pair *LHS = static_cast<const id_macro_pair*>(a);
550   const id_macro_pair *RHS = static_cast<const id_macro_pair*>(b);
551   return LHS->first->getName().compare(RHS->first->getName());
552 }
553 
554 static void DoPrintMacros(Preprocessor &PP, raw_ostream *OS) {
555   // Ignore unknown pragmas.
556   PP.AddPragmaHandler(new EmptyPragmaHandler());
557 
558   // -dM mode just scans and ignores all tokens in the files, then dumps out
559   // the macro table at the end.
560   PP.EnterMainSourceFile();
561 
562   Token Tok;
563   do PP.Lex(Tok);
564   while (Tok.isNot(tok::eof));
565 
566   SmallVector<id_macro_pair, 128>
567     MacrosByID(PP.macro_begin(), PP.macro_end());
568   llvm::array_pod_sort(MacrosByID.begin(), MacrosByID.end(), MacroIDCompare);
569 
570   for (unsigned i = 0, e = MacrosByID.size(); i != e; ++i) {
571     MacroInfo &MI = *MacrosByID[i].second;
572     // Ignore computed macros like __LINE__ and friends.
573     if (MI.isBuiltinMacro()) continue;
574 
575     PrintMacroDefinition(*MacrosByID[i].first, MI, PP, *OS);
576     *OS << '\n';
577   }
578 }
579 
580 /// DoPrintPreprocessedInput - This implements -E mode.
581 ///
582 void clang::DoPrintPreprocessedInput(Preprocessor &PP, raw_ostream *OS,
583                                      const PreprocessorOutputOptions &Opts) {
584   // Show macros with no output is handled specially.
585   if (!Opts.ShowCPP) {
586     assert(Opts.ShowMacros && "Not yet implemented!");
587     DoPrintMacros(PP, OS);
588     return;
589   }
590 
591   // Inform the preprocessor whether we want it to retain comments or not, due
592   // to -C or -CC.
593   PP.SetCommentRetentionState(Opts.ShowComments, Opts.ShowMacroComments);
594 
595   PrintPPOutputPPCallbacks *Callbacks =
596       new PrintPPOutputPPCallbacks(PP, *OS, !Opts.ShowLineMarkers,
597                                    Opts.ShowMacros);
598   PP.AddPragmaHandler(new UnknownPragmaHandler("#pragma", Callbacks));
599   PP.AddPragmaHandler("GCC", new UnknownPragmaHandler("#pragma GCC",Callbacks));
600   PP.AddPragmaHandler("clang",
601                       new UnknownPragmaHandler("#pragma clang", Callbacks));
602 
603   PP.addPPCallbacks(Callbacks);
604 
605   // After we have configured the preprocessor, enter the main file.
606   PP.EnterMainSourceFile();
607 
608   // Consume all of the tokens that come from the predefines buffer.  Those
609   // should not be emitted into the output and are guaranteed to be at the
610   // start.
611   const SourceManager &SourceMgr = PP.getSourceManager();
612   Token Tok;
613   do {
614     PP.Lex(Tok);
615     if (Tok.is(tok::eof) || !Tok.getLocation().isFileID())
616       break;
617 
618     PresumedLoc PLoc = SourceMgr.getPresumedLoc(Tok.getLocation());
619     if (PLoc.isInvalid())
620       break;
621 
622     if (strcmp(PLoc.getFilename(), "<built-in>"))
623       break;
624   } while (true);
625 
626   // Read all the preprocessed tokens, printing them out to the stream.
627   PrintPreprocessedTokens(PP, Tok, Callbacks, *OS);
628   *OS << '\n';
629 }
630