PrintPreprocessedOutput.cpp revision eef63e0997e0f6d6436736ea919b851cfe34955a 
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/Config/config.h"
28#include "llvm/Support/raw_ostream.h"
29#include <cstdio>
30using namespace clang;
31
32/// PrintMacroDefinition - Print a macro definition in a form that will be
33/// properly accepted back as a definition.
34static void PrintMacroDefinition(const IdentifierInfo &II, const MacroInfo &MI,
35                                 Preprocessor &PP, llvm::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
79namespace {
80class PrintPPOutputPPCallbacks : public PPCallbacks {
81  Preprocessor &PP;
82  SourceManager &SM;
83  TokenConcatenation ConcatInfo;
84public:
85  llvm::raw_ostream &OS;
86private:
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;
97public:
98  PrintPPOutputPPCallbacks(Preprocessor &pp, llvm::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().Microsoft;
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  virtual void Ident(SourceLocation Loc, const std::string &str);
122  virtual void PragmaComment(SourceLocation Loc, const IdentifierInfo *Kind,
123                             const std::string &Str);
124  virtual void PragmaMessage(SourceLocation Loc, llvm::StringRef Str);
125
126  bool HandleFirstTokOnLine(Token &Tok);
127  bool MoveToLine(SourceLocation Loc) {
128    PresumedLoc PLoc = SM.getPresumedLoc(Loc);
129    if (PLoc.isInvalid())
130      return false;
131    return MoveToLine(PLoc.getLine());
132  }
133  bool MoveToLine(unsigned LineNo);
134
135  bool AvoidConcat(const Token &PrevPrevTok, const Token &PrevTok,
136                   const Token &Tok) {
137    return ConcatInfo.AvoidConcat(PrevPrevTok, PrevTok, Tok);
138  }
139  void WriteLineInfo(unsigned LineNo, const char *Extra=0, unsigned ExtraLen=0);
140  bool LineMarkersAreDisabled() const { return DisableLineMarkers; }
141  void HandleNewlinesInToken(const char *TokStr, unsigned Len);
142
143  /// MacroDefined - This hook is called whenever a macro definition is seen.
144  void MacroDefined(const Token &MacroNameTok, const MacroInfo *MI);
145
146  /// MacroUndefined - This hook is called whenever a macro #undef is seen.
147  void MacroUndefined(const Token &MacroNameTok, const MacroInfo *MI);
148};
149}  // end anonymous namespace
150
151void PrintPPOutputPPCallbacks::WriteLineInfo(unsigned LineNo,
152                                             const char *Extra,
153                                             unsigned ExtraLen) {
154  if (EmittedTokensOnThisLine || EmittedMacroOnThisLine) {
155    OS << '\n';
156    EmittedTokensOnThisLine = false;
157    EmittedMacroOnThisLine = false;
158  }
159
160  // Emit #line directives or GNU line markers depending on what mode we're in.
161  if (UseLineDirective) {
162    OS << "#line" << ' ' << LineNo << ' ' << '"';
163    OS.write(CurFilename.data(), CurFilename.size());
164    OS << '"';
165  } else {
166    OS << '#' << ' ' << LineNo << ' ' << '"';
167    OS.write(CurFilename.data(), CurFilename.size());
168    OS << '"';
169
170    if (ExtraLen)
171      OS.write(Extra, ExtraLen);
172
173    if (FileType == SrcMgr::C_System)
174      OS.write(" 3", 2);
175    else if (FileType == SrcMgr::C_ExternCSystem)
176      OS.write(" 3 4", 4);
177  }
178  OS << '\n';
179}
180
181/// MoveToLine - Move the output to the source line specified by the location
182/// object.  We can do this by emitting some number of \n's, or be emitting a
183/// #line directive.  This returns false if already at the specified line, true
184/// if some newlines were emitted.
185bool PrintPPOutputPPCallbacks::MoveToLine(unsigned LineNo) {
186  // If this line is "close enough" to the original line, just print newlines,
187  // otherwise print a #line directive.
188  if (LineNo-CurLine <= 8) {
189    if (LineNo-CurLine == 1)
190      OS << '\n';
191    else if (LineNo == CurLine)
192      return false;    // Spelling line moved, but instantiation line didn't.
193    else {
194      const char *NewLines = "\n\n\n\n\n\n\n\n";
195      OS.write(NewLines, LineNo-CurLine);
196    }
197  } else if (!DisableLineMarkers) {
198    // Emit a #line or line marker.
199    WriteLineInfo(LineNo, 0, 0);
200  } else {
201    // Okay, we're in -P mode, which turns off line markers.  However, we still
202    // need to emit a newline between tokens on different lines.
203    if (EmittedTokensOnThisLine || EmittedMacroOnThisLine) {
204      OS << '\n';
205      EmittedTokensOnThisLine = false;
206      EmittedMacroOnThisLine = false;
207    }
208  }
209
210  CurLine = LineNo;
211  return true;
212}
213
214bool PrintPPOutputPPCallbacks::StartNewLineIfNeeded() {
215  if (EmittedTokensOnThisLine || EmittedMacroOnThisLine) {
216    OS << '\n';
217    EmittedTokensOnThisLine = false;
218    EmittedMacroOnThisLine = false;
219    ++CurLine;
220    return true;
221  }
222
223  return false;
224}
225
226/// FileChanged - Whenever the preprocessor enters or exits a #include file
227/// it invokes this handler.  Update our conception of the current source
228/// position.
229void PrintPPOutputPPCallbacks::FileChanged(SourceLocation Loc,
230                                           FileChangeReason Reason,
231                                       SrcMgr::CharacteristicKind NewFileType) {
232  // Unless we are exiting a #include, make sure to skip ahead to the line the
233  // #include directive was at.
234  SourceManager &SourceMgr = SM;
235
236  PresumedLoc UserLoc = SourceMgr.getPresumedLoc(Loc);
237  if (UserLoc.isInvalid())
238    return;
239
240  unsigned NewLine = UserLoc.getLine();
241
242  if (Reason == PPCallbacks::EnterFile) {
243    SourceLocation IncludeLoc = UserLoc.getIncludeLoc();
244    if (IncludeLoc.isValid())
245      MoveToLine(IncludeLoc);
246  } else if (Reason == PPCallbacks::SystemHeaderPragma) {
247    MoveToLine(NewLine);
248
249    // TODO GCC emits the # directive for this directive on the line AFTER the
250    // directive and emits a bunch of spaces that aren't needed.  Emulate this
251    // strange behavior.
252  }
253
254  CurLine = NewLine;
255
256  CurFilename.clear();
257  CurFilename += UserLoc.getFilename();
258  Lexer::Stringify(CurFilename);
259  FileType = NewFileType;
260
261  if (DisableLineMarkers) return;
262
263  if (!Initialized) {
264    WriteLineInfo(CurLine);
265    Initialized = true;
266  }
267
268  switch (Reason) {
269  case PPCallbacks::EnterFile:
270    WriteLineInfo(CurLine, " 1", 2);
271    break;
272  case PPCallbacks::ExitFile:
273    WriteLineInfo(CurLine, " 2", 2);
274    break;
275  case PPCallbacks::SystemHeaderPragma:
276  case PPCallbacks::RenameFile:
277    WriteLineInfo(CurLine);
278    break;
279  }
280}
281
282/// Ident - Handle #ident directives when read by the preprocessor.
283///
284void PrintPPOutputPPCallbacks::Ident(SourceLocation Loc, const std::string &S) {
285  MoveToLine(Loc);
286
287  OS.write("#ident ", strlen("#ident "));
288  OS.write(&S[0], S.size());
289  EmittedTokensOnThisLine = true;
290}
291
292/// MacroDefined - This hook is called whenever a macro definition is seen.
293void PrintPPOutputPPCallbacks::MacroDefined(const Token &MacroNameTok,
294                                            const MacroInfo *MI) {
295  // Only print out macro definitions in -dD mode.
296  if (!DumpDefines ||
297      // Ignore __FILE__ etc.
298      MI->isBuiltinMacro()) return;
299
300  MoveToLine(MI->getDefinitionLoc());
301  PrintMacroDefinition(*MacroNameTok.getIdentifierInfo(), *MI, PP, OS);
302  EmittedMacroOnThisLine = true;
303}
304
305void PrintPPOutputPPCallbacks::MacroUndefined(const Token &MacroNameTok,
306                                              const MacroInfo *MI) {
307  // Only print out macro definitions in -dD mode.
308  if (!DumpDefines) return;
309
310  MoveToLine(MacroNameTok.getLocation());
311  OS << "#undef " << MacroNameTok.getIdentifierInfo()->getName();
312  EmittedMacroOnThisLine = true;
313}
314
315void PrintPPOutputPPCallbacks::PragmaComment(SourceLocation Loc,
316                                             const IdentifierInfo *Kind,
317                                             const std::string &Str) {
318  MoveToLine(Loc);
319  OS << "#pragma comment(" << Kind->getName();
320
321  if (!Str.empty()) {
322    OS << ", \"";
323
324    for (unsigned i = 0, e = Str.size(); i != e; ++i) {
325      unsigned char Char = Str[i];
326      if (isprint(Char) && Char != '\\' && Char != '"')
327        OS << (char)Char;
328      else  // Output anything hard as an octal escape.
329        OS << '\\'
330           << (char)('0'+ ((Char >> 6) & 7))
331           << (char)('0'+ ((Char >> 3) & 7))
332           << (char)('0'+ ((Char >> 0) & 7));
333    }
334    OS << '"';
335  }
336
337  OS << ')';
338  EmittedTokensOnThisLine = true;
339}
340
341void PrintPPOutputPPCallbacks::PragmaMessage(SourceLocation Loc,
342                                             llvm::StringRef Str) {
343  MoveToLine(Loc);
344  OS << "#pragma message(";
345
346  OS << '"';
347
348  for (unsigned i = 0, e = Str.size(); i != e; ++i) {
349    unsigned char Char = Str[i];
350    if (isprint(Char) && Char != '\\' && Char != '"')
351      OS << (char)Char;
352    else  // Output anything hard as an octal escape.
353      OS << '\\'
354         << (char)('0'+ ((Char >> 6) & 7))
355         << (char)('0'+ ((Char >> 3) & 7))
356         << (char)('0'+ ((Char >> 0) & 7));
357  }
358  OS << '"';
359
360  OS << ')';
361  EmittedTokensOnThisLine = true;
362}
363
364
365/// HandleFirstTokOnLine - When emitting a preprocessed file in -E mode, this
366/// is called for the first token on each new line.  If this really is the start
367/// of a new logical line, handle it and return true, otherwise return false.
368/// This may not be the start of a logical line because the "start of line"
369/// marker is set for spelling lines, not instantiation ones.
370bool PrintPPOutputPPCallbacks::HandleFirstTokOnLine(Token &Tok) {
371  // Figure out what line we went to and insert the appropriate number of
372  // newline characters.
373  if (!MoveToLine(Tok.getLocation()))
374    return false;
375
376  // Print out space characters so that the first token on a line is
377  // indented for easy reading.
378  unsigned ColNo = SM.getInstantiationColumnNumber(Tok.getLocation());
379
380  // This hack prevents stuff like:
381  // #define HASH #
382  // HASH define foo bar
383  // From having the # character end up at column 1, which makes it so it
384  // is not handled as a #define next time through the preprocessor if in
385  // -fpreprocessed mode.
386  if (ColNo <= 1 && Tok.is(tok::hash))
387    OS << ' ';
388
389  // Otherwise, indent the appropriate number of spaces.
390  for (; ColNo > 1; --ColNo)
391    OS << ' ';
392
393  return true;
394}
395
396void PrintPPOutputPPCallbacks::HandleNewlinesInToken(const char *TokStr,
397                                                     unsigned Len) {
398  unsigned NumNewlines = 0;
399  for (; Len; --Len, ++TokStr) {
400    if (*TokStr != '\n' &&
401        *TokStr != '\r')
402      continue;
403
404    ++NumNewlines;
405
406    // If we have \n\r or \r\n, skip both and count as one line.
407    if (Len != 1 &&
408        (TokStr[1] == '\n' || TokStr[1] == '\r') &&
409        TokStr[0] != TokStr[1])
410      ++TokStr, --Len;
411  }
412
413  if (NumNewlines == 0) return;
414
415  CurLine += NumNewlines;
416}
417
418
419namespace {
420struct UnknownPragmaHandler : public PragmaHandler {
421  const char *Prefix;
422  PrintPPOutputPPCallbacks *Callbacks;
423
424  UnknownPragmaHandler(const char *prefix, PrintPPOutputPPCallbacks *callbacks)
425    : Prefix(prefix), Callbacks(callbacks) {}
426  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
427                            Token &PragmaTok) {
428    // Figure out what line we went to and insert the appropriate number of
429    // newline characters.
430    Callbacks->StartNewLineIfNeeded();
431    Callbacks->MoveToLine(PragmaTok.getLocation());
432    Callbacks->OS.write(Prefix, strlen(Prefix));
433    Callbacks->SetEmittedTokensOnThisLine();
434    // Read and print all of the pragma tokens.
435    while (PragmaTok.isNot(tok::eom)) {
436      if (PragmaTok.hasLeadingSpace())
437        Callbacks->OS << ' ';
438      std::string TokSpell = PP.getSpelling(PragmaTok);
439      Callbacks->OS.write(&TokSpell[0], TokSpell.size());
440      PP.LexUnexpandedToken(PragmaTok);
441    }
442    Callbacks->StartNewLineIfNeeded();
443  }
444};
445} // end anonymous namespace
446
447
448static void PrintPreprocessedTokens(Preprocessor &PP, Token &Tok,
449                                    PrintPPOutputPPCallbacks *Callbacks,
450                                    llvm::raw_ostream &OS) {
451  char Buffer[256];
452  Token PrevPrevTok, PrevTok;
453  PrevPrevTok.startToken();
454  PrevTok.startToken();
455  while (1) {
456
457    // If this token is at the start of a line, emit newlines if needed.
458    if (Tok.isAtStartOfLine() && Callbacks->HandleFirstTokOnLine(Tok)) {
459      // done.
460    } else if (Tok.hasLeadingSpace() ||
461               // If we haven't emitted a token on this line yet, PrevTok isn't
462               // useful to look at and no concatenation could happen anyway.
463               (Callbacks->hasEmittedTokensOnThisLine() &&
464                // Don't print "-" next to "-", it would form "--".
465                Callbacks->AvoidConcat(PrevPrevTok, PrevTok, Tok))) {
466      OS << ' ';
467    }
468
469    if (IdentifierInfo *II = Tok.getIdentifierInfo()) {
470      OS << II->getName();
471    } else if (Tok.isLiteral() && !Tok.needsCleaning() &&
472               Tok.getLiteralData()) {
473      OS.write(Tok.getLiteralData(), Tok.getLength());
474    } else if (Tok.getLength() < 256) {
475      const char *TokPtr = Buffer;
476      unsigned Len = PP.getSpelling(Tok, TokPtr);
477      OS.write(TokPtr, Len);
478
479      // Tokens that can contain embedded newlines need to adjust our current
480      // line number.
481      if (Tok.getKind() == tok::comment)
482        Callbacks->HandleNewlinesInToken(TokPtr, Len);
483    } else {
484      std::string S = PP.getSpelling(Tok);
485      OS.write(&S[0], S.size());
486
487      // Tokens that can contain embedded newlines need to adjust our current
488      // line number.
489      if (Tok.getKind() == tok::comment)
490        Callbacks->HandleNewlinesInToken(&S[0], S.size());
491    }
492    Callbacks->SetEmittedTokensOnThisLine();
493
494    if (Tok.is(tok::eof)) break;
495
496    PrevPrevTok = PrevTok;
497    PrevTok = Tok;
498    PP.Lex(Tok);
499  }
500}
501
502typedef std::pair<IdentifierInfo*, MacroInfo*> id_macro_pair;
503static int MacroIDCompare(const void* a, const void* b) {
504  const id_macro_pair *LHS = static_cast<const id_macro_pair*>(a);
505  const id_macro_pair *RHS = static_cast<const id_macro_pair*>(b);
506  return LHS->first->getName().compare(RHS->first->getName());
507}
508
509static void DoPrintMacros(Preprocessor &PP, llvm::raw_ostream *OS) {
510  // Ignore unknown pragmas.
511  PP.AddPragmaHandler(new EmptyPragmaHandler());
512
513  // -dM mode just scans and ignores all tokens in the files, then dumps out
514  // the macro table at the end.
515  PP.EnterMainSourceFile();
516
517  Token Tok;
518  do PP.Lex(Tok);
519  while (Tok.isNot(tok::eof));
520
521  llvm::SmallVector<id_macro_pair, 128>
522    MacrosByID(PP.macro_begin(), PP.macro_end());
523  llvm::array_pod_sort(MacrosByID.begin(), MacrosByID.end(), MacroIDCompare);
524
525  for (unsigned i = 0, e = MacrosByID.size(); i != e; ++i) {
526    MacroInfo &MI = *MacrosByID[i].second;
527    // Ignore computed macros like __LINE__ and friends.
528    if (MI.isBuiltinMacro()) continue;
529
530    PrintMacroDefinition(*MacrosByID[i].first, MI, PP, *OS);
531    *OS << '\n';
532  }
533}
534
535/// DoPrintPreprocessedInput - This implements -E mode.
536///
537void clang::DoPrintPreprocessedInput(Preprocessor &PP, llvm::raw_ostream *OS,
538                                     const PreprocessorOutputOptions &Opts) {
539  // Show macros with no output is handled specially.
540  if (!Opts.ShowCPP) {
541    assert(Opts.ShowMacros && "Not yet implemented!");
542    DoPrintMacros(PP, OS);
543    return;
544  }
545
546  // Inform the preprocessor whether we want it to retain comments or not, due
547  // to -C or -CC.
548  PP.SetCommentRetentionState(Opts.ShowComments, Opts.ShowMacroComments);
549
550  PrintPPOutputPPCallbacks *Callbacks =
551      new PrintPPOutputPPCallbacks(PP, *OS, !Opts.ShowLineMarkers,
552                                   Opts.ShowMacros);
553  PP.AddPragmaHandler(new UnknownPragmaHandler("#pragma", Callbacks));
554  PP.AddPragmaHandler("GCC", new UnknownPragmaHandler("#pragma GCC",Callbacks));
555  PP.AddPragmaHandler("clang",
556                      new UnknownPragmaHandler("#pragma clang", Callbacks));
557
558  PP.addPPCallbacks(Callbacks);
559
560  // After we have configured the preprocessor, enter the main file.
561  PP.EnterMainSourceFile();
562
563  // Consume all of the tokens that come from the predefines buffer.  Those
564  // should not be emitted into the output and are guaranteed to be at the
565  // start.
566  const SourceManager &SourceMgr = PP.getSourceManager();
567  Token Tok;
568  do {
569    PP.Lex(Tok);
570    if (Tok.is(tok::eof) || !Tok.getLocation().isFileID())
571      break;
572
573    PresumedLoc PLoc = SourceMgr.getPresumedLoc(Tok.getLocation());
574    if (PLoc.isInvalid())
575      break;
576
577    if (strcmp(PLoc.getFilename(), "<built-in>"))
578      break;
579  } while (true);
580
581  // Read all the preprocessed tokens, printing them out to the stream.
582  PrintPreprocessedTokens(PP, Tok, Callbacks, *OS);
583  *OS << '\n';
584}
585