1//===--- Preprocess.cpp - C Language Family Preprocessor Implementation ---===//
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 file implements the Preprocessor interface.
11//
12//===----------------------------------------------------------------------===//
13//
14// Options to support:
15//   -H       - Print the name of each header file used.
16//   -d[DNI] - Dump various things.
17//   -fworking-directory - #line's with preprocessor's working dir.
18//   -fpreprocessed
19//   -dependency-file,-M,-MM,-MF,-MG,-MP,-MT,-MQ,-MD,-MMD
20//   -W*
21//   -w
22//
23// Messages to emit:
24//   "Multiple include guards may be useful for:\n"
25//
26//===----------------------------------------------------------------------===//
27
28#include "clang/Lex/Preprocessor.h"
29#include "clang/Basic/FileManager.h"
30#include "clang/Basic/SourceManager.h"
31#include "clang/Basic/TargetInfo.h"
32#include "clang/Lex/CodeCompletionHandler.h"
33#include "clang/Lex/ExternalPreprocessorSource.h"
34#include "clang/Lex/HeaderSearch.h"
35#include "clang/Lex/LexDiagnostic.h"
36#include "clang/Lex/LiteralSupport.h"
37#include "clang/Lex/MacroArgs.h"
38#include "clang/Lex/MacroInfo.h"
39#include "clang/Lex/ModuleLoader.h"
40#include "clang/Lex/Pragma.h"
41#include "clang/Lex/PreprocessingRecord.h"
42#include "clang/Lex/PreprocessorOptions.h"
43#include "clang/Lex/ScratchBuffer.h"
44#include "llvm/ADT/APFloat.h"
45#include "llvm/ADT/STLExtras.h"
46#include "llvm/ADT/SmallString.h"
47#include "llvm/ADT/StringExtras.h"
48#include "llvm/Support/Capacity.h"
49#include "llvm/Support/ConvertUTF.h"
50#include "llvm/Support/MemoryBuffer.h"
51#include "llvm/Support/raw_ostream.h"
52using namespace clang;
53
54//===----------------------------------------------------------------------===//
55ExternalPreprocessorSource::~ExternalPreprocessorSource() { }
56
57Preprocessor::Preprocessor(IntrusiveRefCntPtr<PreprocessorOptions> PPOpts,
58                           DiagnosticsEngine &diags, LangOptions &opts,
59                           SourceManager &SM, HeaderSearch &Headers,
60                           ModuleLoader &TheModuleLoader,
61                           IdentifierInfoLookup *IILookup, bool OwnsHeaders,
62                           TranslationUnitKind TUKind)
63    : PPOpts(PPOpts), Diags(&diags), LangOpts(opts), Target(nullptr),
64      FileMgr(Headers.getFileMgr()), SourceMgr(SM), HeaderInfo(Headers),
65      TheModuleLoader(TheModuleLoader), ExternalSource(nullptr),
66      Identifiers(opts, IILookup), IncrementalProcessing(false), TUKind(TUKind),
67      CodeComplete(nullptr), CodeCompletionFile(nullptr),
68      CodeCompletionOffset(0), LastTokenWasAt(false),
69      ModuleImportExpectsIdentifier(false), CodeCompletionReached(0),
70      SkipMainFilePreamble(0, true), CurPPLexer(nullptr),
71      CurDirLookup(nullptr), CurLexerKind(CLK_Lexer), CurSubmodule(nullptr),
72      Callbacks(nullptr), MacroArgCache(nullptr), Record(nullptr),
73      MIChainHead(nullptr), MICache(nullptr), DeserialMIChainHead(nullptr) {
74  OwnsHeaderSearch = OwnsHeaders;
75
76  ScratchBuf = new ScratchBuffer(SourceMgr);
77  CounterValue = 0; // __COUNTER__ starts at 0.
78
79  // Clear stats.
80  NumDirectives = NumDefined = NumUndefined = NumPragma = 0;
81  NumIf = NumElse = NumEndif = 0;
82  NumEnteredSourceFiles = 0;
83  NumMacroExpanded = NumFnMacroExpanded = NumBuiltinMacroExpanded = 0;
84  NumFastMacroExpanded = NumTokenPaste = NumFastTokenPaste = 0;
85  MaxIncludeStackDepth = 0;
86  NumSkipped = 0;
87
88  // Default to discarding comments.
89  KeepComments = false;
90  KeepMacroComments = false;
91  SuppressIncludeNotFoundError = false;
92
93  // Macro expansion is enabled.
94  DisableMacroExpansion = false;
95  MacroExpansionInDirectivesOverride = false;
96  InMacroArgs = false;
97  InMacroArgPreExpansion = false;
98  NumCachedTokenLexers = 0;
99  PragmasEnabled = true;
100  ParsingIfOrElifDirective = false;
101  PreprocessedOutput = false;
102
103  CachedLexPos = 0;
104
105  // We haven't read anything from the external source.
106  ReadMacrosFromExternalSource = false;
107
108  // "Poison" __VA_ARGS__, which can only appear in the expansion of a macro.
109  // This gets unpoisoned where it is allowed.
110  (Ident__VA_ARGS__ = getIdentifierInfo("__VA_ARGS__"))->setIsPoisoned();
111  SetPoisonReason(Ident__VA_ARGS__,diag::ext_pp_bad_vaargs_use);
112
113  // Initialize the pragma handlers.
114  PragmaHandlers = new PragmaNamespace(StringRef());
115  RegisterBuiltinPragmas();
116
117  // Initialize builtin macros like __LINE__ and friends.
118  RegisterBuiltinMacros();
119
120  if(LangOpts.Borland) {
121    Ident__exception_info        = getIdentifierInfo("_exception_info");
122    Ident___exception_info       = getIdentifierInfo("__exception_info");
123    Ident_GetExceptionInfo       = getIdentifierInfo("GetExceptionInformation");
124    Ident__exception_code        = getIdentifierInfo("_exception_code");
125    Ident___exception_code       = getIdentifierInfo("__exception_code");
126    Ident_GetExceptionCode       = getIdentifierInfo("GetExceptionCode");
127    Ident__abnormal_termination  = getIdentifierInfo("_abnormal_termination");
128    Ident___abnormal_termination = getIdentifierInfo("__abnormal_termination");
129    Ident_AbnormalTermination    = getIdentifierInfo("AbnormalTermination");
130  } else {
131    Ident__exception_info = Ident__exception_code = nullptr;
132    Ident__abnormal_termination = Ident___exception_info = nullptr;
133    Ident___exception_code = Ident___abnormal_termination = nullptr;
134    Ident_GetExceptionInfo = Ident_GetExceptionCode = nullptr;
135    Ident_AbnormalTermination = nullptr;
136  }
137}
138
139Preprocessor::~Preprocessor() {
140  assert(BacktrackPositions.empty() && "EnableBacktrack/Backtrack imbalance!");
141
142  IncludeMacroStack.clear();
143
144  // Free any macro definitions.
145  for (MacroInfoChain *I = MIChainHead ; I ; I = I->Next)
146    I->MI.Destroy();
147
148  // Free any cached macro expanders.
149  // This populates MacroArgCache, so all TokenLexers need to be destroyed
150  // before the code below that frees up the MacroArgCache list.
151  for (unsigned i = 0, e = NumCachedTokenLexers; i != e; ++i)
152    delete TokenLexerCache[i];
153  CurTokenLexer.reset();
154
155  for (DeserializedMacroInfoChain *I = DeserialMIChainHead ; I ; I = I->Next)
156    I->MI.Destroy();
157
158  // Free any cached MacroArgs.
159  for (MacroArgs *ArgList = MacroArgCache; ArgList;)
160    ArgList = ArgList->deallocate();
161
162  // Release pragma information.
163  delete PragmaHandlers;
164
165  // Delete the scratch buffer info.
166  delete ScratchBuf;
167
168  // Delete the header search info, if we own it.
169  if (OwnsHeaderSearch)
170    delete &HeaderInfo;
171
172  delete Callbacks;
173}
174
175void Preprocessor::Initialize(const TargetInfo &Target) {
176  assert((!this->Target || this->Target == &Target) &&
177         "Invalid override of target information");
178  this->Target = &Target;
179
180  // Initialize information about built-ins.
181  BuiltinInfo.InitializeTarget(Target);
182  HeaderInfo.setTarget(Target);
183}
184
185void Preprocessor::setPTHManager(PTHManager* pm) {
186  PTH.reset(pm);
187  FileMgr.addStatCache(PTH->createStatCache());
188}
189
190void Preprocessor::DumpToken(const Token &Tok, bool DumpFlags) const {
191  llvm::errs() << tok::getTokenName(Tok.getKind()) << " '"
192               << getSpelling(Tok) << "'";
193
194  if (!DumpFlags) return;
195
196  llvm::errs() << "\t";
197  if (Tok.isAtStartOfLine())
198    llvm::errs() << " [StartOfLine]";
199  if (Tok.hasLeadingSpace())
200    llvm::errs() << " [LeadingSpace]";
201  if (Tok.isExpandDisabled())
202    llvm::errs() << " [ExpandDisabled]";
203  if (Tok.needsCleaning()) {
204    const char *Start = SourceMgr.getCharacterData(Tok.getLocation());
205    llvm::errs() << " [UnClean='" << StringRef(Start, Tok.getLength())
206                 << "']";
207  }
208
209  llvm::errs() << "\tLoc=<";
210  DumpLocation(Tok.getLocation());
211  llvm::errs() << ">";
212}
213
214void Preprocessor::DumpLocation(SourceLocation Loc) const {
215  Loc.dump(SourceMgr);
216}
217
218void Preprocessor::DumpMacro(const MacroInfo &MI) const {
219  llvm::errs() << "MACRO: ";
220  for (unsigned i = 0, e = MI.getNumTokens(); i != e; ++i) {
221    DumpToken(MI.getReplacementToken(i));
222    llvm::errs() << "  ";
223  }
224  llvm::errs() << "\n";
225}
226
227void Preprocessor::PrintStats() {
228  llvm::errs() << "\n*** Preprocessor Stats:\n";
229  llvm::errs() << NumDirectives << " directives found:\n";
230  llvm::errs() << "  " << NumDefined << " #define.\n";
231  llvm::errs() << "  " << NumUndefined << " #undef.\n";
232  llvm::errs() << "  #include/#include_next/#import:\n";
233  llvm::errs() << "    " << NumEnteredSourceFiles << " source files entered.\n";
234  llvm::errs() << "    " << MaxIncludeStackDepth << " max include stack depth\n";
235  llvm::errs() << "  " << NumIf << " #if/#ifndef/#ifdef.\n";
236  llvm::errs() << "  " << NumElse << " #else/#elif.\n";
237  llvm::errs() << "  " << NumEndif << " #endif.\n";
238  llvm::errs() << "  " << NumPragma << " #pragma.\n";
239  llvm::errs() << NumSkipped << " #if/#ifndef#ifdef regions skipped\n";
240
241  llvm::errs() << NumMacroExpanded << "/" << NumFnMacroExpanded << "/"
242             << NumBuiltinMacroExpanded << " obj/fn/builtin macros expanded, "
243             << NumFastMacroExpanded << " on the fast path.\n";
244  llvm::errs() << (NumFastTokenPaste+NumTokenPaste)
245             << " token paste (##) operations performed, "
246             << NumFastTokenPaste << " on the fast path.\n";
247
248  llvm::errs() << "\nPreprocessor Memory: " << getTotalMemory() << "B total";
249
250  llvm::errs() << "\n  BumpPtr: " << BP.getTotalMemory();
251  llvm::errs() << "\n  Macro Expanded Tokens: "
252               << llvm::capacity_in_bytes(MacroExpandedTokens);
253  llvm::errs() << "\n  Predefines Buffer: " << Predefines.capacity();
254  llvm::errs() << "\n  Macros: " << llvm::capacity_in_bytes(Macros);
255  llvm::errs() << "\n  #pragma push_macro Info: "
256               << llvm::capacity_in_bytes(PragmaPushMacroInfo);
257  llvm::errs() << "\n  Poison Reasons: "
258               << llvm::capacity_in_bytes(PoisonReasons);
259  llvm::errs() << "\n  Comment Handlers: "
260               << llvm::capacity_in_bytes(CommentHandlers) << "\n";
261}
262
263Preprocessor::macro_iterator
264Preprocessor::macro_begin(bool IncludeExternalMacros) const {
265  if (IncludeExternalMacros && ExternalSource &&
266      !ReadMacrosFromExternalSource) {
267    ReadMacrosFromExternalSource = true;
268    ExternalSource->ReadDefinedMacros();
269  }
270
271  return Macros.begin();
272}
273
274size_t Preprocessor::getTotalMemory() const {
275  return BP.getTotalMemory()
276    + llvm::capacity_in_bytes(MacroExpandedTokens)
277    + Predefines.capacity() /* Predefines buffer. */
278    + llvm::capacity_in_bytes(Macros)
279    + llvm::capacity_in_bytes(PragmaPushMacroInfo)
280    + llvm::capacity_in_bytes(PoisonReasons)
281    + llvm::capacity_in_bytes(CommentHandlers);
282}
283
284Preprocessor::macro_iterator
285Preprocessor::macro_end(bool IncludeExternalMacros) const {
286  if (IncludeExternalMacros && ExternalSource &&
287      !ReadMacrosFromExternalSource) {
288    ReadMacrosFromExternalSource = true;
289    ExternalSource->ReadDefinedMacros();
290  }
291
292  return Macros.end();
293}
294
295/// \brief Compares macro tokens with a specified token value sequence.
296static bool MacroDefinitionEquals(const MacroInfo *MI,
297                                  ArrayRef<TokenValue> Tokens) {
298  return Tokens.size() == MI->getNumTokens() &&
299      std::equal(Tokens.begin(), Tokens.end(), MI->tokens_begin());
300}
301
302StringRef Preprocessor::getLastMacroWithSpelling(
303                                    SourceLocation Loc,
304                                    ArrayRef<TokenValue> Tokens) const {
305  SourceLocation BestLocation;
306  StringRef BestSpelling;
307  for (Preprocessor::macro_iterator I = macro_begin(), E = macro_end();
308       I != E; ++I) {
309    if (!I->second->getMacroInfo()->isObjectLike())
310      continue;
311    const MacroDirective::DefInfo
312      Def = I->second->findDirectiveAtLoc(Loc, SourceMgr);
313    if (!Def)
314      continue;
315    if (!MacroDefinitionEquals(Def.getMacroInfo(), Tokens))
316      continue;
317    SourceLocation Location = Def.getLocation();
318    // Choose the macro defined latest.
319    if (BestLocation.isInvalid() ||
320        (Location.isValid() &&
321         SourceMgr.isBeforeInTranslationUnit(BestLocation, Location))) {
322      BestLocation = Location;
323      BestSpelling = I->first->getName();
324    }
325  }
326  return BestSpelling;
327}
328
329void Preprocessor::recomputeCurLexerKind() {
330  if (CurLexer)
331    CurLexerKind = CLK_Lexer;
332  else if (CurPTHLexer)
333    CurLexerKind = CLK_PTHLexer;
334  else if (CurTokenLexer)
335    CurLexerKind = CLK_TokenLexer;
336  else
337    CurLexerKind = CLK_CachingLexer;
338}
339
340bool Preprocessor::SetCodeCompletionPoint(const FileEntry *File,
341                                          unsigned CompleteLine,
342                                          unsigned CompleteColumn) {
343  assert(File);
344  assert(CompleteLine && CompleteColumn && "Starts from 1:1");
345  assert(!CodeCompletionFile && "Already set");
346
347  using llvm::MemoryBuffer;
348
349  // Load the actual file's contents.
350  bool Invalid = false;
351  const MemoryBuffer *Buffer = SourceMgr.getMemoryBufferForFile(File, &Invalid);
352  if (Invalid)
353    return true;
354
355  // Find the byte position of the truncation point.
356  const char *Position = Buffer->getBufferStart();
357  for (unsigned Line = 1; Line < CompleteLine; ++Line) {
358    for (; *Position; ++Position) {
359      if (*Position != '\r' && *Position != '\n')
360        continue;
361
362      // Eat \r\n or \n\r as a single line.
363      if ((Position[1] == '\r' || Position[1] == '\n') &&
364          Position[0] != Position[1])
365        ++Position;
366      ++Position;
367      break;
368    }
369  }
370
371  Position += CompleteColumn - 1;
372
373  // Insert '\0' at the code-completion point.
374  if (Position < Buffer->getBufferEnd()) {
375    CodeCompletionFile = File;
376    CodeCompletionOffset = Position - Buffer->getBufferStart();
377
378    MemoryBuffer *NewBuffer =
379        MemoryBuffer::getNewUninitMemBuffer(Buffer->getBufferSize() + 1,
380                                            Buffer->getBufferIdentifier());
381    char *NewBuf = const_cast<char*>(NewBuffer->getBufferStart());
382    char *NewPos = std::copy(Buffer->getBufferStart(), Position, NewBuf);
383    *NewPos = '\0';
384    std::copy(Position, Buffer->getBufferEnd(), NewPos+1);
385    SourceMgr.overrideFileContents(File, NewBuffer);
386  }
387
388  return false;
389}
390
391void Preprocessor::CodeCompleteNaturalLanguage() {
392  if (CodeComplete)
393    CodeComplete->CodeCompleteNaturalLanguage();
394  setCodeCompletionReached();
395}
396
397/// getSpelling - This method is used to get the spelling of a token into a
398/// SmallVector. Note that the returned StringRef may not point to the
399/// supplied buffer if a copy can be avoided.
400StringRef Preprocessor::getSpelling(const Token &Tok,
401                                          SmallVectorImpl<char> &Buffer,
402                                          bool *Invalid) const {
403  // NOTE: this has to be checked *before* testing for an IdentifierInfo.
404  if (Tok.isNot(tok::raw_identifier) && !Tok.hasUCN()) {
405    // Try the fast path.
406    if (const IdentifierInfo *II = Tok.getIdentifierInfo())
407      return II->getName();
408  }
409
410  // Resize the buffer if we need to copy into it.
411  if (Tok.needsCleaning())
412    Buffer.resize(Tok.getLength());
413
414  const char *Ptr = Buffer.data();
415  unsigned Len = getSpelling(Tok, Ptr, Invalid);
416  return StringRef(Ptr, Len);
417}
418
419/// CreateString - Plop the specified string into a scratch buffer and return a
420/// location for it.  If specified, the source location provides a source
421/// location for the token.
422void Preprocessor::CreateString(StringRef Str, Token &Tok,
423                                SourceLocation ExpansionLocStart,
424                                SourceLocation ExpansionLocEnd) {
425  Tok.setLength(Str.size());
426
427  const char *DestPtr;
428  SourceLocation Loc = ScratchBuf->getToken(Str.data(), Str.size(), DestPtr);
429
430  if (ExpansionLocStart.isValid())
431    Loc = SourceMgr.createExpansionLoc(Loc, ExpansionLocStart,
432                                       ExpansionLocEnd, Str.size());
433  Tok.setLocation(Loc);
434
435  // If this is a raw identifier or a literal token, set the pointer data.
436  if (Tok.is(tok::raw_identifier))
437    Tok.setRawIdentifierData(DestPtr);
438  else if (Tok.isLiteral())
439    Tok.setLiteralData(DestPtr);
440}
441
442Module *Preprocessor::getCurrentModule() {
443  if (getLangOpts().CurrentModule.empty())
444    return nullptr;
445
446  return getHeaderSearchInfo().lookupModule(getLangOpts().CurrentModule);
447}
448
449//===----------------------------------------------------------------------===//
450// Preprocessor Initialization Methods
451//===----------------------------------------------------------------------===//
452
453
454/// EnterMainSourceFile - Enter the specified FileID as the main source file,
455/// which implicitly adds the builtin defines etc.
456void Preprocessor::EnterMainSourceFile() {
457  // We do not allow the preprocessor to reenter the main file.  Doing so will
458  // cause FileID's to accumulate information from both runs (e.g. #line
459  // information) and predefined macros aren't guaranteed to be set properly.
460  assert(NumEnteredSourceFiles == 0 && "Cannot reenter the main file!");
461  FileID MainFileID = SourceMgr.getMainFileID();
462
463  // If MainFileID is loaded it means we loaded an AST file, no need to enter
464  // a main file.
465  if (!SourceMgr.isLoadedFileID(MainFileID)) {
466    // Enter the main file source buffer.
467    EnterSourceFile(MainFileID, nullptr, SourceLocation());
468
469    // If we've been asked to skip bytes in the main file (e.g., as part of a
470    // precompiled preamble), do so now.
471    if (SkipMainFilePreamble.first > 0)
472      CurLexer->SkipBytes(SkipMainFilePreamble.first,
473                          SkipMainFilePreamble.second);
474
475    // Tell the header info that the main file was entered.  If the file is later
476    // #imported, it won't be re-entered.
477    if (const FileEntry *FE = SourceMgr.getFileEntryForID(MainFileID))
478      HeaderInfo.IncrementIncludeCount(FE);
479  }
480
481  // Preprocess Predefines to populate the initial preprocessor state.
482  llvm::MemoryBuffer *SB =
483    llvm::MemoryBuffer::getMemBufferCopy(Predefines, "<built-in>");
484  assert(SB && "Cannot create predefined source buffer");
485  FileID FID = SourceMgr.createFileID(SB);
486  assert(!FID.isInvalid() && "Could not create FileID for predefines?");
487  setPredefinesFileID(FID);
488
489  // Start parsing the predefines.
490  EnterSourceFile(FID, nullptr, SourceLocation());
491}
492
493void Preprocessor::EndSourceFile() {
494  // Notify the client that we reached the end of the source file.
495  if (Callbacks)
496    Callbacks->EndOfMainFile();
497}
498
499//===----------------------------------------------------------------------===//
500// Lexer Event Handling.
501//===----------------------------------------------------------------------===//
502
503/// LookUpIdentifierInfo - Given a tok::raw_identifier token, look up the
504/// identifier information for the token and install it into the token,
505/// updating the token kind accordingly.
506IdentifierInfo *Preprocessor::LookUpIdentifierInfo(Token &Identifier) const {
507  assert(!Identifier.getRawIdentifier().empty() && "No raw identifier data!");
508
509  // Look up this token, see if it is a macro, or if it is a language keyword.
510  IdentifierInfo *II;
511  if (!Identifier.needsCleaning() && !Identifier.hasUCN()) {
512    // No cleaning needed, just use the characters from the lexed buffer.
513    II = getIdentifierInfo(Identifier.getRawIdentifier());
514  } else {
515    // Cleaning needed, alloca a buffer, clean into it, then use the buffer.
516    SmallString<64> IdentifierBuffer;
517    StringRef CleanedStr = getSpelling(Identifier, IdentifierBuffer);
518
519    if (Identifier.hasUCN()) {
520      SmallString<64> UCNIdentifierBuffer;
521      expandUCNs(UCNIdentifierBuffer, CleanedStr);
522      II = getIdentifierInfo(UCNIdentifierBuffer);
523    } else {
524      II = getIdentifierInfo(CleanedStr);
525    }
526  }
527
528  // Update the token info (identifier info and appropriate token kind).
529  Identifier.setIdentifierInfo(II);
530  Identifier.setKind(II->getTokenID());
531
532  return II;
533}
534
535void Preprocessor::SetPoisonReason(IdentifierInfo *II, unsigned DiagID) {
536  PoisonReasons[II] = DiagID;
537}
538
539void Preprocessor::PoisonSEHIdentifiers(bool Poison) {
540  assert(Ident__exception_code && Ident__exception_info);
541  assert(Ident___exception_code && Ident___exception_info);
542  Ident__exception_code->setIsPoisoned(Poison);
543  Ident___exception_code->setIsPoisoned(Poison);
544  Ident_GetExceptionCode->setIsPoisoned(Poison);
545  Ident__exception_info->setIsPoisoned(Poison);
546  Ident___exception_info->setIsPoisoned(Poison);
547  Ident_GetExceptionInfo->setIsPoisoned(Poison);
548  Ident__abnormal_termination->setIsPoisoned(Poison);
549  Ident___abnormal_termination->setIsPoisoned(Poison);
550  Ident_AbnormalTermination->setIsPoisoned(Poison);
551}
552
553void Preprocessor::HandlePoisonedIdentifier(Token & Identifier) {
554  assert(Identifier.getIdentifierInfo() &&
555         "Can't handle identifiers without identifier info!");
556  llvm::DenseMap<IdentifierInfo*,unsigned>::const_iterator it =
557    PoisonReasons.find(Identifier.getIdentifierInfo());
558  if(it == PoisonReasons.end())
559    Diag(Identifier, diag::err_pp_used_poisoned_id);
560  else
561    Diag(Identifier,it->second) << Identifier.getIdentifierInfo();
562}
563
564/// HandleIdentifier - This callback is invoked when the lexer reads an
565/// identifier.  This callback looks up the identifier in the map and/or
566/// potentially macro expands it or turns it into a named token (like 'for').
567///
568/// Note that callers of this method are guarded by checking the
569/// IdentifierInfo's 'isHandleIdentifierCase' bit.  If this method changes, the
570/// IdentifierInfo methods that compute these properties will need to change to
571/// match.
572bool Preprocessor::HandleIdentifier(Token &Identifier) {
573  assert(Identifier.getIdentifierInfo() &&
574         "Can't handle identifiers without identifier info!");
575
576  IdentifierInfo &II = *Identifier.getIdentifierInfo();
577
578  // If the information about this identifier is out of date, update it from
579  // the external source.
580  // We have to treat __VA_ARGS__ in a special way, since it gets
581  // serialized with isPoisoned = true, but our preprocessor may have
582  // unpoisoned it if we're defining a C99 macro.
583  if (II.isOutOfDate()) {
584    bool CurrentIsPoisoned = false;
585    if (&II == Ident__VA_ARGS__)
586      CurrentIsPoisoned = Ident__VA_ARGS__->isPoisoned();
587
588    ExternalSource->updateOutOfDateIdentifier(II);
589    Identifier.setKind(II.getTokenID());
590
591    if (&II == Ident__VA_ARGS__)
592      II.setIsPoisoned(CurrentIsPoisoned);
593  }
594
595  // If this identifier was poisoned, and if it was not produced from a macro
596  // expansion, emit an error.
597  if (II.isPoisoned() && CurPPLexer) {
598    HandlePoisonedIdentifier(Identifier);
599  }
600
601  // If this is a macro to be expanded, do it.
602  if (MacroDirective *MD = getMacroDirective(&II)) {
603    MacroInfo *MI = MD->getMacroInfo();
604    if (!DisableMacroExpansion) {
605      if (!Identifier.isExpandDisabled() && MI->isEnabled()) {
606        // C99 6.10.3p10: If the preprocessing token immediately after the
607        // macro name isn't a '(', this macro should not be expanded.
608        if (!MI->isFunctionLike() || isNextPPTokenLParen())
609          return HandleMacroExpandedIdentifier(Identifier, MD);
610      } else {
611        // C99 6.10.3.4p2 says that a disabled macro may never again be
612        // expanded, even if it's in a context where it could be expanded in the
613        // future.
614        Identifier.setFlag(Token::DisableExpand);
615        if (MI->isObjectLike() || isNextPPTokenLParen())
616          Diag(Identifier, diag::pp_disabled_macro_expansion);
617      }
618    }
619  }
620
621  // If this identifier is a keyword in C++11, produce a warning. Don't warn if
622  // we're not considering macro expansion, since this identifier might be the
623  // name of a macro.
624  // FIXME: This warning is disabled in cases where it shouldn't be, like
625  //   "#define constexpr constexpr", "int constexpr;"
626  if (II.isCXX11CompatKeyword() && !DisableMacroExpansion) {
627    Diag(Identifier, diag::warn_cxx11_keyword) << II.getName();
628    // Don't diagnose this keyword again in this translation unit.
629    II.setIsCXX11CompatKeyword(false);
630  }
631
632  // C++ 2.11p2: If this is an alternative representation of a C++ operator,
633  // then we act as if it is the actual operator and not the textual
634  // representation of it.
635  if (II.isCPlusPlusOperatorKeyword())
636    Identifier.setIdentifierInfo(nullptr);
637
638  // If this is an extension token, diagnose its use.
639  // We avoid diagnosing tokens that originate from macro definitions.
640  // FIXME: This warning is disabled in cases where it shouldn't be,
641  // like "#define TY typeof", "TY(1) x".
642  if (II.isExtensionToken() && !DisableMacroExpansion)
643    Diag(Identifier, diag::ext_token_used);
644
645  // If this is the 'import' contextual keyword following an '@', note
646  // that the next token indicates a module name.
647  //
648  // Note that we do not treat 'import' as a contextual
649  // keyword when we're in a caching lexer, because caching lexers only get
650  // used in contexts where import declarations are disallowed.
651  if (LastTokenWasAt && II.isModulesImport() && !InMacroArgs &&
652      !DisableMacroExpansion && getLangOpts().Modules &&
653      CurLexerKind != CLK_CachingLexer) {
654    ModuleImportLoc = Identifier.getLocation();
655    ModuleImportPath.clear();
656    ModuleImportExpectsIdentifier = true;
657    CurLexerKind = CLK_LexAfterModuleImport;
658  }
659  return true;
660}
661
662void Preprocessor::Lex(Token &Result) {
663  // We loop here until a lex function retuns a token; this avoids recursion.
664  bool ReturnedToken;
665  do {
666    switch (CurLexerKind) {
667    case CLK_Lexer:
668      ReturnedToken = CurLexer->Lex(Result);
669      break;
670    case CLK_PTHLexer:
671      ReturnedToken = CurPTHLexer->Lex(Result);
672      break;
673    case CLK_TokenLexer:
674      ReturnedToken = CurTokenLexer->Lex(Result);
675      break;
676    case CLK_CachingLexer:
677      CachingLex(Result);
678      ReturnedToken = true;
679      break;
680    case CLK_LexAfterModuleImport:
681      LexAfterModuleImport(Result);
682      ReturnedToken = true;
683      break;
684    }
685  } while (!ReturnedToken);
686
687  LastTokenWasAt = Result.is(tok::at);
688}
689
690
691/// \brief Lex a token following the 'import' contextual keyword.
692///
693void Preprocessor::LexAfterModuleImport(Token &Result) {
694  // Figure out what kind of lexer we actually have.
695  recomputeCurLexerKind();
696
697  // Lex the next token.
698  Lex(Result);
699
700  // The token sequence
701  //
702  //   import identifier (. identifier)*
703  //
704  // indicates a module import directive. We already saw the 'import'
705  // contextual keyword, so now we're looking for the identifiers.
706  if (ModuleImportExpectsIdentifier && Result.getKind() == tok::identifier) {
707    // We expected to see an identifier here, and we did; continue handling
708    // identifiers.
709    ModuleImportPath.push_back(std::make_pair(Result.getIdentifierInfo(),
710                                              Result.getLocation()));
711    ModuleImportExpectsIdentifier = false;
712    CurLexerKind = CLK_LexAfterModuleImport;
713    return;
714  }
715
716  // If we're expecting a '.' or a ';', and we got a '.', then wait until we
717  // see the next identifier.
718  if (!ModuleImportExpectsIdentifier && Result.getKind() == tok::period) {
719    ModuleImportExpectsIdentifier = true;
720    CurLexerKind = CLK_LexAfterModuleImport;
721    return;
722  }
723
724  // If we have a non-empty module path, load the named module.
725  if (!ModuleImportPath.empty() && getLangOpts().Modules) {
726    Module *Imported = TheModuleLoader.loadModule(ModuleImportLoc,
727                                                  ModuleImportPath,
728                                                  Module::MacrosVisible,
729                                                  /*IsIncludeDirective=*/false);
730    if (Callbacks)
731      Callbacks->moduleImport(ModuleImportLoc, ModuleImportPath, Imported);
732  }
733}
734
735bool Preprocessor::FinishLexStringLiteral(Token &Result, std::string &String,
736                                          const char *DiagnosticTag,
737                                          bool AllowMacroExpansion) {
738  // We need at least one string literal.
739  if (Result.isNot(tok::string_literal)) {
740    Diag(Result, diag::err_expected_string_literal)
741      << /*Source='in...'*/0 << DiagnosticTag;
742    return false;
743  }
744
745  // Lex string literal tokens, optionally with macro expansion.
746  SmallVector<Token, 4> StrToks;
747  do {
748    StrToks.push_back(Result);
749
750    if (Result.hasUDSuffix())
751      Diag(Result, diag::err_invalid_string_udl);
752
753    if (AllowMacroExpansion)
754      Lex(Result);
755    else
756      LexUnexpandedToken(Result);
757  } while (Result.is(tok::string_literal));
758
759  // Concatenate and parse the strings.
760  StringLiteralParser Literal(StrToks, *this);
761  assert(Literal.isAscii() && "Didn't allow wide strings in");
762
763  if (Literal.hadError)
764    return false;
765
766  if (Literal.Pascal) {
767    Diag(StrToks[0].getLocation(), diag::err_expected_string_literal)
768      << /*Source='in...'*/0 << DiagnosticTag;
769    return false;
770  }
771
772  String = Literal.GetString();
773  return true;
774}
775
776bool Preprocessor::parseSimpleIntegerLiteral(Token &Tok, uint64_t &Value) {
777  assert(Tok.is(tok::numeric_constant));
778  SmallString<8> IntegerBuffer;
779  bool NumberInvalid = false;
780  StringRef Spelling = getSpelling(Tok, IntegerBuffer, &NumberInvalid);
781  if (NumberInvalid)
782    return false;
783  NumericLiteralParser Literal(Spelling, Tok.getLocation(), *this);
784  if (Literal.hadError || !Literal.isIntegerLiteral() || Literal.hasUDSuffix())
785    return false;
786  llvm::APInt APVal(64, 0);
787  if (Literal.GetIntegerValue(APVal))
788    return false;
789  Lex(Tok);
790  Value = APVal.getLimitedValue();
791  return true;
792}
793
794void Preprocessor::addCommentHandler(CommentHandler *Handler) {
795  assert(Handler && "NULL comment handler");
796  assert(std::find(CommentHandlers.begin(), CommentHandlers.end(), Handler) ==
797         CommentHandlers.end() && "Comment handler already registered");
798  CommentHandlers.push_back(Handler);
799}
800
801void Preprocessor::removeCommentHandler(CommentHandler *Handler) {
802  std::vector<CommentHandler *>::iterator Pos
803  = std::find(CommentHandlers.begin(), CommentHandlers.end(), Handler);
804  assert(Pos != CommentHandlers.end() && "Comment handler not registered");
805  CommentHandlers.erase(Pos);
806}
807
808bool Preprocessor::HandleComment(Token &result, SourceRange Comment) {
809  bool AnyPendingTokens = false;
810  for (std::vector<CommentHandler *>::iterator H = CommentHandlers.begin(),
811       HEnd = CommentHandlers.end();
812       H != HEnd; ++H) {
813    if ((*H)->HandleComment(*this, Comment))
814      AnyPendingTokens = true;
815  }
816  if (!AnyPendingTokens || getCommentRetentionState())
817    return false;
818  Lex(result);
819  return true;
820}
821
822ModuleLoader::~ModuleLoader() { }
823
824CommentHandler::~CommentHandler() { }
825
826CodeCompletionHandler::~CodeCompletionHandler() { }
827
828void Preprocessor::createPreprocessingRecord() {
829  if (Record)
830    return;
831
832  Record = new PreprocessingRecord(getSourceManager());
833  addPPCallbacks(Record);
834}
835