ASTUnit.cpp revision 5535d5721b6bfb5df9583bc0632da910a176109d 
1//===--- ASTUnit.cpp - ASTUnit utility ------------------------------------===//
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// ASTUnit Implementation.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Frontend/ASTUnit.h"
15#include "clang/Frontend/PCHWriter.h"
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/ASTConsumer.h"
18#include "clang/AST/DeclVisitor.h"
19#include "clang/AST/TypeOrdering.h"
20#include "clang/AST/StmtVisitor.h"
21#include "clang/Driver/Compilation.h"
22#include "clang/Driver/Driver.h"
23#include "clang/Driver/Job.h"
24#include "clang/Driver/Tool.h"
25#include "clang/Frontend/CompilerInstance.h"
26#include "clang/Frontend/FrontendActions.h"
27#include "clang/Frontend/FrontendDiagnostic.h"
28#include "clang/Frontend/FrontendOptions.h"
29#include "clang/Frontend/PCHReader.h"
30#include "clang/Lex/HeaderSearch.h"
31#include "clang/Lex/Preprocessor.h"
32#include "clang/Basic/TargetOptions.h"
33#include "clang/Basic/TargetInfo.h"
34#include "clang/Basic/Diagnostic.h"
35#include "llvm/Support/MemoryBuffer.h"
36#include "llvm/System/Host.h"
37#include "llvm/System/Path.h"
38#include "llvm/Support/raw_ostream.h"
39#include "llvm/Support/Timer.h"
40#include <cstdlib>
41#include <cstdio>
42#include <sys/stat.h>
43using namespace clang;
44
45/// \brief After failing to build a precompiled preamble (due to
46/// errors in the source that occurs in the preamble), the number of
47/// reparses during which we'll skip even trying to precompile the
48/// preamble.
49const unsigned DefaultPreambleRebuildInterval = 5;
50
51ASTUnit::ASTUnit(bool _MainFileIsAST)
52  : CaptureDiagnostics(false), MainFileIsAST(_MainFileIsAST),
53    CompleteTranslationUnit(true), ConcurrencyCheckValue(CheckUnlocked),
54    PreambleRebuildCounter(0), SavedMainFileBuffer(0),
55    ShouldCacheCodeCompletionResults(false) {
56}
57
58ASTUnit::~ASTUnit() {
59  ConcurrencyCheckValue = CheckLocked;
60  CleanTemporaryFiles();
61  if (!PreambleFile.empty())
62    llvm::sys::Path(PreambleFile).eraseFromDisk();
63
64  // Free the buffers associated with remapped files. We are required to
65  // perform this operation here because we explicitly request that the
66  // compiler instance *not* free these buffers for each invocation of the
67  // parser.
68  if (Invocation.get()) {
69    PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
70    for (PreprocessorOptions::remapped_file_buffer_iterator
71           FB = PPOpts.remapped_file_buffer_begin(),
72           FBEnd = PPOpts.remapped_file_buffer_end();
73         FB != FBEnd;
74         ++FB)
75      delete FB->second;
76  }
77
78  delete SavedMainFileBuffer;
79
80  ClearCachedCompletionResults();
81
82  for (unsigned I = 0, N = Timers.size(); I != N; ++I)
83    delete Timers[I];
84}
85
86void ASTUnit::CleanTemporaryFiles() {
87  for (unsigned I = 0, N = TemporaryFiles.size(); I != N; ++I)
88    TemporaryFiles[I].eraseFromDisk();
89  TemporaryFiles.clear();
90}
91
92/// \brief Determine the set of code-completion contexts in which this
93/// declaration should be shown.
94static unsigned getDeclShowContexts(NamedDecl *ND,
95                                    const LangOptions &LangOpts) {
96  if (isa<UsingShadowDecl>(ND))
97    ND = dyn_cast<NamedDecl>(ND->getUnderlyingDecl());
98  if (!ND)
99    return 0;
100
101  unsigned Contexts = 0;
102  if (isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND) ||
103      isa<ClassTemplateDecl>(ND) || isa<TemplateTemplateParmDecl>(ND)) {
104    // Types can appear in these contexts.
105    if (LangOpts.CPlusPlus || !isa<TagDecl>(ND))
106      Contexts |= (1 << (CodeCompletionContext::CCC_TopLevel - 1))
107                | (1 << (CodeCompletionContext::CCC_ObjCIvarList - 1))
108                | (1 << (CodeCompletionContext::CCC_ClassStructUnion - 1))
109                | (1 << (CodeCompletionContext::CCC_Statement - 1))
110                | (1 << (CodeCompletionContext::CCC_Type - 1));
111
112    // In C++, types can appear in expressions contexts (for functional casts).
113    if (LangOpts.CPlusPlus)
114      Contexts |= (1 << (CodeCompletionContext::CCC_Expression - 1));
115
116    // In Objective-C, message sends can send interfaces. In Objective-C++,
117    // all types are available due to functional casts.
118    if (LangOpts.CPlusPlus || isa<ObjCInterfaceDecl>(ND))
119      Contexts |= (1 << (CodeCompletionContext::CCC_ObjCMessageReceiver - 1));
120
121    // Deal with tag names.
122    if (isa<EnumDecl>(ND)) {
123      Contexts |= (1 << (CodeCompletionContext::CCC_EnumTag - 1));
124
125      // Part of the nested-name-specifier.
126      if (LangOpts.CPlusPlus0x)
127        Contexts |= (1 << (CodeCompletionContext::CCC_MemberAccess - 1));
128    } else if (RecordDecl *Record = dyn_cast<RecordDecl>(ND)) {
129      if (Record->isUnion())
130        Contexts |= (1 << (CodeCompletionContext::CCC_UnionTag - 1));
131      else
132        Contexts |= (1 << (CodeCompletionContext::CCC_ClassOrStructTag - 1));
133
134      // Part of the nested-name-specifier.
135      if (LangOpts.CPlusPlus)
136        Contexts |= (1 << (CodeCompletionContext::CCC_MemberAccess - 1));
137    }
138  } else if (isa<ValueDecl>(ND) || isa<FunctionTemplateDecl>(ND)) {
139    // Values can appear in these contexts.
140    Contexts = (1 << (CodeCompletionContext::CCC_Statement - 1))
141             | (1 << (CodeCompletionContext::CCC_Expression - 1))
142             | (1 << (CodeCompletionContext::CCC_ObjCMessageReceiver - 1));
143  } else if (isa<ObjCProtocolDecl>(ND)) {
144    Contexts = (1 << (CodeCompletionContext::CCC_ObjCProtocolName - 1));
145  } else if (isa<NamespaceDecl>(ND) || isa<NamespaceAliasDecl>(ND)) {
146    Contexts = (1 << (CodeCompletionContext::CCC_TopLevel - 1))
147             | (1 << (CodeCompletionContext::CCC_ObjCIvarList - 1))
148             | (1 << (CodeCompletionContext::CCC_ClassStructUnion - 1))
149             | (1 << (CodeCompletionContext::CCC_Statement - 1))
150             | (1 << (CodeCompletionContext::CCC_Expression - 1))
151             | (1 << (CodeCompletionContext::CCC_ObjCMessageReceiver - 1))
152             | (1 << (CodeCompletionContext::CCC_Namespace - 1));
153
154    // Part of the nested-name-specifier.
155    Contexts |= (1 << (CodeCompletionContext::CCC_MemberAccess - 1))
156             | (1 << (CodeCompletionContext::CCC_EnumTag - 1))
157             | (1 << (CodeCompletionContext::CCC_UnionTag - 1))
158             | (1 << (CodeCompletionContext::CCC_ClassOrStructTag - 1))
159             | (1 << (CodeCompletionContext::CCC_Type - 1));
160  }
161
162  return Contexts;
163}
164
165void ASTUnit::CacheCodeCompletionResults() {
166  if (!TheSema)
167    return;
168
169  llvm::Timer *CachingTimer = 0;
170  if (TimerGroup.get()) {
171    CachingTimer = new llvm::Timer("Cache global code completions",
172                                   *TimerGroup);
173    CachingTimer->startTimer();
174    Timers.push_back(CachingTimer);
175  }
176
177  // Clear out the previous results.
178  ClearCachedCompletionResults();
179
180  // Gather the set of global code completions.
181  typedef CodeCompleteConsumer::Result Result;
182  llvm::SmallVector<Result, 8> Results;
183  TheSema->GatherGlobalCodeCompletions(Results);
184
185  // Translate global code completions into cached completions.
186  llvm::DenseMap<CanQualType, unsigned> CompletionTypes;
187
188  for (unsigned I = 0, N = Results.size(); I != N; ++I) {
189    switch (Results[I].Kind) {
190    case Result::RK_Declaration: {
191      CachedCodeCompletionResult CachedResult;
192      CachedResult.Completion = Results[I].CreateCodeCompletionString(*TheSema);
193      CachedResult.ShowInContexts = getDeclShowContexts(Results[I].Declaration,
194                                                        Ctx->getLangOptions());
195      CachedResult.Priority = Results[I].Priority;
196      CachedResult.Kind = Results[I].CursorKind;
197
198      // Keep track of the type of this completion in an ASTContext-agnostic
199      // way.
200      QualType UsageType = getDeclUsageType(*Ctx, Results[I].Declaration);
201      if (UsageType.isNull()) {
202        CachedResult.TypeClass = STC_Void;
203        CachedResult.Type = 0;
204      } else {
205        CanQualType CanUsageType
206          = Ctx->getCanonicalType(UsageType.getUnqualifiedType());
207        CachedResult.TypeClass = getSimplifiedTypeClass(CanUsageType);
208
209        // Determine whether we have already seen this type. If so, we save
210        // ourselves the work of formatting the type string by using the
211        // temporary, CanQualType-based hash table to find the associated value.
212        unsigned &TypeValue = CompletionTypes[CanUsageType];
213        if (TypeValue == 0) {
214          TypeValue = CompletionTypes.size();
215          CachedCompletionTypes[QualType(CanUsageType).getAsString()]
216            = TypeValue;
217        }
218
219        CachedResult.Type = TypeValue;
220      }
221
222      CachedCompletionResults.push_back(CachedResult);
223      break;
224    }
225
226    case Result::RK_Keyword:
227    case Result::RK_Pattern:
228      // Ignore keywords and patterns; we don't care, since they are so
229      // easily regenerated.
230      break;
231
232    case Result::RK_Macro: {
233      CachedCodeCompletionResult CachedResult;
234      CachedResult.Completion = Results[I].CreateCodeCompletionString(*TheSema);
235      CachedResult.ShowInContexts
236        = (1 << (CodeCompletionContext::CCC_TopLevel - 1))
237        | (1 << (CodeCompletionContext::CCC_ObjCInterface - 1))
238        | (1 << (CodeCompletionContext::CCC_ObjCImplementation - 1))
239        | (1 << (CodeCompletionContext::CCC_ObjCIvarList - 1))
240        | (1 << (CodeCompletionContext::CCC_ClassStructUnion - 1))
241        | (1 << (CodeCompletionContext::CCC_Statement - 1))
242        | (1 << (CodeCompletionContext::CCC_Expression - 1))
243        | (1 << (CodeCompletionContext::CCC_ObjCMessageReceiver - 1));
244      CachedResult.Priority = Results[I].Priority;
245      CachedResult.Kind = Results[I].CursorKind;
246      CachedResult.TypeClass = STC_Void;
247      CachedResult.Type = 0;
248      CachedCompletionResults.push_back(CachedResult);
249      break;
250    }
251    }
252    Results[I].Destroy();
253  }
254
255  if (CachingTimer)
256    CachingTimer->stopTimer();
257}
258
259void ASTUnit::ClearCachedCompletionResults() {
260  for (unsigned I = 0, N = CachedCompletionResults.size(); I != N; ++I)
261    delete CachedCompletionResults[I].Completion;
262  CachedCompletionResults.clear();
263  CachedCompletionTypes.clear();
264}
265
266namespace {
267
268/// \brief Gathers information from PCHReader that will be used to initialize
269/// a Preprocessor.
270class PCHInfoCollector : public PCHReaderListener {
271  LangOptions &LangOpt;
272  HeaderSearch &HSI;
273  std::string &TargetTriple;
274  std::string &Predefines;
275  unsigned &Counter;
276
277  unsigned NumHeaderInfos;
278
279public:
280  PCHInfoCollector(LangOptions &LangOpt, HeaderSearch &HSI,
281                   std::string &TargetTriple, std::string &Predefines,
282                   unsigned &Counter)
283    : LangOpt(LangOpt), HSI(HSI), TargetTriple(TargetTriple),
284      Predefines(Predefines), Counter(Counter), NumHeaderInfos(0) {}
285
286  virtual bool ReadLanguageOptions(const LangOptions &LangOpts) {
287    LangOpt = LangOpts;
288    return false;
289  }
290
291  virtual bool ReadTargetTriple(llvm::StringRef Triple) {
292    TargetTriple = Triple;
293    return false;
294  }
295
296  virtual bool ReadPredefinesBuffer(const PCHPredefinesBlocks &Buffers,
297                                    llvm::StringRef OriginalFileName,
298                                    std::string &SuggestedPredefines) {
299    Predefines = Buffers[0].Data;
300    for (unsigned I = 1, N = Buffers.size(); I != N; ++I) {
301      Predefines += Buffers[I].Data;
302    }
303    return false;
304  }
305
306  virtual void ReadHeaderFileInfo(const HeaderFileInfo &HFI, unsigned ID) {
307    HSI.setHeaderFileInfoForUID(HFI, NumHeaderInfos++);
308  }
309
310  virtual void ReadCounter(unsigned Value) {
311    Counter = Value;
312  }
313};
314
315class StoredDiagnosticClient : public DiagnosticClient {
316  llvm::SmallVectorImpl<StoredDiagnostic> &StoredDiags;
317
318public:
319  explicit StoredDiagnosticClient(
320                          llvm::SmallVectorImpl<StoredDiagnostic> &StoredDiags)
321    : StoredDiags(StoredDiags) { }
322
323  virtual void HandleDiagnostic(Diagnostic::Level Level,
324                                const DiagnosticInfo &Info);
325};
326
327/// \brief RAII object that optionally captures diagnostics, if
328/// there is no diagnostic client to capture them already.
329class CaptureDroppedDiagnostics {
330  Diagnostic &Diags;
331  StoredDiagnosticClient Client;
332  DiagnosticClient *PreviousClient;
333
334public:
335  CaptureDroppedDiagnostics(bool RequestCapture, Diagnostic &Diags,
336                           llvm::SmallVectorImpl<StoredDiagnostic> &StoredDiags)
337    : Diags(Diags), Client(StoredDiags), PreviousClient(Diags.getClient())
338  {
339    if (RequestCapture || Diags.getClient() == 0)
340      Diags.setClient(&Client);
341  }
342
343  ~CaptureDroppedDiagnostics() {
344    Diags.setClient(PreviousClient);
345  }
346};
347
348} // anonymous namespace
349
350void StoredDiagnosticClient::HandleDiagnostic(Diagnostic::Level Level,
351                                              const DiagnosticInfo &Info) {
352  StoredDiags.push_back(StoredDiagnostic(Level, Info));
353}
354
355const std::string &ASTUnit::getOriginalSourceFileName() {
356  return OriginalSourceFile;
357}
358
359const std::string &ASTUnit::getPCHFileName() {
360  assert(isMainFileAST() && "Not an ASTUnit from a PCH file!");
361  return static_cast<PCHReader *>(Ctx->getExternalSource())->getFileName();
362}
363
364ASTUnit *ASTUnit::LoadFromPCHFile(const std::string &Filename,
365                                  llvm::IntrusiveRefCntPtr<Diagnostic> Diags,
366                                  bool OnlyLocalDecls,
367                                  RemappedFile *RemappedFiles,
368                                  unsigned NumRemappedFiles,
369                                  bool CaptureDiagnostics) {
370  llvm::OwningPtr<ASTUnit> AST(new ASTUnit(true));
371
372  if (!Diags.getPtr()) {
373    // No diagnostics engine was provided, so create our own diagnostics object
374    // with the default options.
375    DiagnosticOptions DiagOpts;
376    Diags = CompilerInstance::createDiagnostics(DiagOpts, 0, 0);
377  }
378
379  AST->CaptureDiagnostics = CaptureDiagnostics;
380  AST->OnlyLocalDecls = OnlyLocalDecls;
381  AST->Diagnostics = Diags;
382  AST->FileMgr.reset(new FileManager);
383  AST->SourceMgr.reset(new SourceManager(AST->getDiagnostics()));
384  AST->HeaderInfo.reset(new HeaderSearch(AST->getFileManager()));
385
386  // If requested, capture diagnostics in the ASTUnit.
387  CaptureDroppedDiagnostics Capture(CaptureDiagnostics, AST->getDiagnostics(),
388                                    AST->StoredDiagnostics);
389
390  for (unsigned I = 0; I != NumRemappedFiles; ++I) {
391    // Create the file entry for the file that we're mapping from.
392    const FileEntry *FromFile
393      = AST->getFileManager().getVirtualFile(RemappedFiles[I].first,
394                                    RemappedFiles[I].second->getBufferSize(),
395                                             0);
396    if (!FromFile) {
397      AST->getDiagnostics().Report(diag::err_fe_remap_missing_from_file)
398        << RemappedFiles[I].first;
399      delete RemappedFiles[I].second;
400      continue;
401    }
402
403    // Override the contents of the "from" file with the contents of
404    // the "to" file.
405    AST->getSourceManager().overrideFileContents(FromFile,
406                                                 RemappedFiles[I].second);
407  }
408
409  // Gather Info for preprocessor construction later on.
410
411  LangOptions LangInfo;
412  HeaderSearch &HeaderInfo = *AST->HeaderInfo.get();
413  std::string TargetTriple;
414  std::string Predefines;
415  unsigned Counter;
416
417  llvm::OwningPtr<PCHReader> Reader;
418
419  Reader.reset(new PCHReader(AST->getSourceManager(), AST->getFileManager(),
420                             AST->getDiagnostics()));
421  Reader->setListener(new PCHInfoCollector(LangInfo, HeaderInfo, TargetTriple,
422                                           Predefines, Counter));
423
424  switch (Reader->ReadPCH(Filename)) {
425  case PCHReader::Success:
426    break;
427
428  case PCHReader::Failure:
429  case PCHReader::IgnorePCH:
430    AST->getDiagnostics().Report(diag::err_fe_unable_to_load_pch);
431    return NULL;
432  }
433
434  AST->OriginalSourceFile = Reader->getOriginalSourceFile();
435
436  // PCH loaded successfully. Now create the preprocessor.
437
438  // Get information about the target being compiled for.
439  //
440  // FIXME: This is broken, we should store the TargetOptions in the PCH.
441  TargetOptions TargetOpts;
442  TargetOpts.ABI = "";
443  TargetOpts.CXXABI = "itanium";
444  TargetOpts.CPU = "";
445  TargetOpts.Features.clear();
446  TargetOpts.Triple = TargetTriple;
447  AST->Target.reset(TargetInfo::CreateTargetInfo(AST->getDiagnostics(),
448                                                 TargetOpts));
449  AST->PP.reset(new Preprocessor(AST->getDiagnostics(), LangInfo,
450                                 *AST->Target.get(),
451                                 AST->getSourceManager(), HeaderInfo));
452  Preprocessor &PP = *AST->PP.get();
453
454  PP.setPredefines(Reader->getSuggestedPredefines());
455  PP.setCounterValue(Counter);
456  Reader->setPreprocessor(PP);
457
458  // Create and initialize the ASTContext.
459
460  AST->Ctx.reset(new ASTContext(LangInfo,
461                                AST->getSourceManager(),
462                                *AST->Target.get(),
463                                PP.getIdentifierTable(),
464                                PP.getSelectorTable(),
465                                PP.getBuiltinInfo(),
466                                /* size_reserve = */0));
467  ASTContext &Context = *AST->Ctx.get();
468
469  Reader->InitializeContext(Context);
470
471  // Attach the PCH reader to the AST context as an external AST
472  // source, so that declarations will be deserialized from the
473  // PCH file as needed.
474  PCHReader *ReaderPtr = Reader.get();
475  llvm::OwningPtr<ExternalASTSource> Source(Reader.take());
476  Context.setExternalSource(Source);
477
478  // Create an AST consumer, even though it isn't used.
479  AST->Consumer.reset(new ASTConsumer);
480
481  // Create a semantic analysis object and tell the PCH reader about it.
482  AST->TheSema.reset(new Sema(PP, Context, *AST->Consumer));
483  AST->TheSema->Initialize();
484  ReaderPtr->InitializeSema(*AST->TheSema);
485
486  return AST.take();
487}
488
489namespace {
490
491class TopLevelDeclTrackerConsumer : public ASTConsumer {
492  ASTUnit &Unit;
493
494public:
495  TopLevelDeclTrackerConsumer(ASTUnit &_Unit) : Unit(_Unit) {}
496
497  void HandleTopLevelDecl(DeclGroupRef D) {
498    for (DeclGroupRef::iterator it = D.begin(), ie = D.end(); it != ie; ++it) {
499      Decl *D = *it;
500      // FIXME: Currently ObjC method declarations are incorrectly being
501      // reported as top-level declarations, even though their DeclContext
502      // is the containing ObjC @interface/@implementation.  This is a
503      // fundamental problem in the parser right now.
504      if (isa<ObjCMethodDecl>(D))
505        continue;
506      Unit.addTopLevelDecl(D);
507    }
508  }
509
510  // We're not interested in "interesting" decls.
511  void HandleInterestingDecl(DeclGroupRef) {}
512};
513
514class TopLevelDeclTrackerAction : public ASTFrontendAction {
515public:
516  ASTUnit &Unit;
517
518  virtual ASTConsumer *CreateASTConsumer(CompilerInstance &CI,
519                                         llvm::StringRef InFile) {
520    return new TopLevelDeclTrackerConsumer(Unit);
521  }
522
523public:
524  TopLevelDeclTrackerAction(ASTUnit &_Unit) : Unit(_Unit) {}
525
526  virtual bool hasCodeCompletionSupport() const { return false; }
527  virtual bool usesCompleteTranslationUnit()  {
528    return Unit.isCompleteTranslationUnit();
529  }
530};
531
532class PrecompilePreambleConsumer : public PCHGenerator {
533  ASTUnit &Unit;
534  std::vector<Decl *> TopLevelDecls;
535
536public:
537  PrecompilePreambleConsumer(ASTUnit &Unit,
538                             const Preprocessor &PP, bool Chaining,
539                             const char *isysroot, llvm::raw_ostream *Out)
540    : PCHGenerator(PP, Chaining, isysroot, Out), Unit(Unit) { }
541
542  virtual void HandleTopLevelDecl(DeclGroupRef D) {
543    for (DeclGroupRef::iterator it = D.begin(), ie = D.end(); it != ie; ++it) {
544      Decl *D = *it;
545      // FIXME: Currently ObjC method declarations are incorrectly being
546      // reported as top-level declarations, even though their DeclContext
547      // is the containing ObjC @interface/@implementation.  This is a
548      // fundamental problem in the parser right now.
549      if (isa<ObjCMethodDecl>(D))
550        continue;
551      TopLevelDecls.push_back(D);
552    }
553  }
554
555  virtual void HandleTranslationUnit(ASTContext &Ctx) {
556    PCHGenerator::HandleTranslationUnit(Ctx);
557    if (!Unit.getDiagnostics().hasErrorOccurred()) {
558      // Translate the top-level declarations we captured during
559      // parsing into declaration IDs in the precompiled
560      // preamble. This will allow us to deserialize those top-level
561      // declarations when requested.
562      for (unsigned I = 0, N = TopLevelDecls.size(); I != N; ++I)
563        Unit.addTopLevelDeclFromPreamble(
564                                      getWriter().getDeclID(TopLevelDecls[I]));
565    }
566  }
567};
568
569class PrecompilePreambleAction : public ASTFrontendAction {
570  ASTUnit &Unit;
571
572public:
573  explicit PrecompilePreambleAction(ASTUnit &Unit) : Unit(Unit) {}
574
575  virtual ASTConsumer *CreateASTConsumer(CompilerInstance &CI,
576                                         llvm::StringRef InFile) {
577    std::string Sysroot;
578    llvm::raw_ostream *OS = 0;
579    bool Chaining;
580    if (GeneratePCHAction::ComputeASTConsumerArguments(CI, InFile, Sysroot,
581                                                       OS, Chaining))
582      return 0;
583
584    const char *isysroot = CI.getFrontendOpts().RelocatablePCH ?
585                             Sysroot.c_str() : 0;
586    return new PrecompilePreambleConsumer(Unit, CI.getPreprocessor(), Chaining,
587                                          isysroot, OS);
588  }
589
590  virtual bool hasCodeCompletionSupport() const { return false; }
591  virtual bool hasASTFileSupport() const { return false; }
592  virtual bool usesCompleteTranslationUnit() { return false; }
593};
594
595}
596
597/// Parse the source file into a translation unit using the given compiler
598/// invocation, replacing the current translation unit.
599///
600/// \returns True if a failure occurred that causes the ASTUnit not to
601/// contain any translation-unit information, false otherwise.
602bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
603  delete SavedMainFileBuffer;
604  SavedMainFileBuffer = 0;
605
606  if (!Invocation.get())
607    return true;
608
609  // Create the compiler instance to use for building the AST.
610  CompilerInstance Clang;
611  Clang.setInvocation(Invocation.take());
612  OriginalSourceFile = Clang.getFrontendOpts().Inputs[0].second;
613
614  // Set up diagnostics, capturing any diagnostics that would
615  // otherwise be dropped.
616  Clang.setDiagnostics(&getDiagnostics());
617  CaptureDroppedDiagnostics Capture(CaptureDiagnostics,
618                                    getDiagnostics(),
619                                    StoredDiagnostics);
620  Clang.setDiagnosticClient(getDiagnostics().getClient());
621
622  // Create the target instance.
623  Clang.setTarget(TargetInfo::CreateTargetInfo(Clang.getDiagnostics(),
624                                               Clang.getTargetOpts()));
625  if (!Clang.hasTarget()) {
626    Clang.takeDiagnosticClient();
627    return true;
628  }
629
630  // Inform the target of the language options.
631  //
632  // FIXME: We shouldn't need to do this, the target should be immutable once
633  // created. This complexity should be lifted elsewhere.
634  Clang.getTarget().setForcedLangOptions(Clang.getLangOpts());
635
636  assert(Clang.getFrontendOpts().Inputs.size() == 1 &&
637         "Invocation must have exactly one source file!");
638  assert(Clang.getFrontendOpts().Inputs[0].first != IK_AST &&
639         "FIXME: AST inputs not yet supported here!");
640  assert(Clang.getFrontendOpts().Inputs[0].first != IK_LLVM_IR &&
641         "IR inputs not support here!");
642
643  // Configure the various subsystems.
644  // FIXME: Should we retain the previous file manager?
645  FileMgr.reset(new FileManager);
646  SourceMgr.reset(new SourceManager(getDiagnostics()));
647  TheSema.reset();
648  Ctx.reset();
649  PP.reset();
650
651  // Clear out old caches and data.
652  TopLevelDecls.clear();
653  CleanTemporaryFiles();
654  PreprocessedEntitiesByFile.clear();
655
656  if (!OverrideMainBuffer)
657    StoredDiagnostics.clear();
658
659  // Create a file manager object to provide access to and cache the filesystem.
660  Clang.setFileManager(&getFileManager());
661
662  // Create the source manager.
663  Clang.setSourceManager(&getSourceManager());
664
665  // If the main file has been overridden due to the use of a preamble,
666  // make that override happen and introduce the preamble.
667  PreprocessorOptions &PreprocessorOpts = Clang.getPreprocessorOpts();
668  std::string PriorImplicitPCHInclude;
669  if (OverrideMainBuffer) {
670    PreprocessorOpts.addRemappedFile(OriginalSourceFile, OverrideMainBuffer);
671    PreprocessorOpts.PrecompiledPreambleBytes.first = Preamble.size();
672    PreprocessorOpts.PrecompiledPreambleBytes.second
673                                                    = PreambleEndsAtStartOfLine;
674    PriorImplicitPCHInclude = PreprocessorOpts.ImplicitPCHInclude;
675    PreprocessorOpts.ImplicitPCHInclude = PreambleFile;
676    PreprocessorOpts.DisablePCHValidation = true;
677
678    // Keep track of the override buffer;
679    SavedMainFileBuffer = OverrideMainBuffer;
680
681    // The stored diagnostic has the old source manager in it; update
682    // the locations to refer into the new source manager. Since we've
683    // been careful to make sure that the source manager's state
684    // before and after are identical, so that we can reuse the source
685    // location itself.
686    for (unsigned I = 0, N = StoredDiagnostics.size(); I != N; ++I) {
687      FullSourceLoc Loc(StoredDiagnostics[I].getLocation(),
688                        getSourceManager());
689      StoredDiagnostics[I].setLocation(Loc);
690    }
691  }
692
693  llvm::OwningPtr<TopLevelDeclTrackerAction> Act;
694  Act.reset(new TopLevelDeclTrackerAction(*this));
695  if (!Act->BeginSourceFile(Clang, Clang.getFrontendOpts().Inputs[0].second,
696                            Clang.getFrontendOpts().Inputs[0].first))
697    goto error;
698
699  Act->Execute();
700
701  // Steal the created target, context, and preprocessor, and take back the
702  // source and file managers.
703  TheSema.reset(Clang.takeSema());
704  Consumer.reset(Clang.takeASTConsumer());
705  Ctx.reset(Clang.takeASTContext());
706  PP.reset(Clang.takePreprocessor());
707  Clang.takeSourceManager();
708  Clang.takeFileManager();
709  Target.reset(Clang.takeTarget());
710
711  Act->EndSourceFile();
712
713  // Remove the overridden buffer we used for the preamble.
714  if (OverrideMainBuffer) {
715    PreprocessorOpts.eraseRemappedFile(
716                               PreprocessorOpts.remapped_file_buffer_end() - 1);
717    PreprocessorOpts.ImplicitPCHInclude = PriorImplicitPCHInclude;
718  }
719
720  Clang.takeDiagnosticClient();
721
722  Invocation.reset(Clang.takeInvocation());
723
724  // If we were asked to cache code-completion results and don't have any
725  // results yet, do so now.
726  if (ShouldCacheCodeCompletionResults && CachedCompletionResults.empty())
727    CacheCodeCompletionResults();
728
729  return false;
730
731error:
732  // Remove the overridden buffer we used for the preamble.
733  if (OverrideMainBuffer) {
734    PreprocessorOpts.eraseRemappedFile(
735                               PreprocessorOpts.remapped_file_buffer_end() - 1);
736    PreprocessorOpts.DisablePCHValidation = true;
737    PreprocessorOpts.ImplicitPCHInclude = PriorImplicitPCHInclude;
738  }
739
740  Clang.takeSourceManager();
741  Clang.takeFileManager();
742  Clang.takeDiagnosticClient();
743  Invocation.reset(Clang.takeInvocation());
744  return true;
745}
746
747/// \brief Simple function to retrieve a path for a preamble precompiled header.
748static std::string GetPreamblePCHPath() {
749  // FIXME: This is lame; sys::Path should provide this function (in particular,
750  // it should know how to find the temporary files dir).
751  // FIXME: This is really lame. I copied this code from the Driver!
752  std::string Error;
753  const char *TmpDir = ::getenv("TMPDIR");
754  if (!TmpDir)
755    TmpDir = ::getenv("TEMP");
756  if (!TmpDir)
757    TmpDir = ::getenv("TMP");
758  if (!TmpDir)
759    TmpDir = "/tmp";
760  llvm::sys::Path P(TmpDir);
761  P.appendComponent("preamble");
762  P.appendSuffix("pch");
763  if (P.createTemporaryFileOnDisk())
764    return std::string();
765
766  return P.str();
767}
768
769/// \brief Compute the preamble for the main file, providing the source buffer
770/// that corresponds to the main file along with a pair (bytes, start-of-line)
771/// that describes the preamble.
772std::pair<llvm::MemoryBuffer *, std::pair<unsigned, bool> >
773ASTUnit::ComputePreamble(CompilerInvocation &Invocation,
774                         unsigned MaxLines, bool &CreatedBuffer) {
775  FrontendOptions &FrontendOpts = Invocation.getFrontendOpts();
776  PreprocessorOptions &PreprocessorOpts
777    = Invocation.getPreprocessorOpts();
778  CreatedBuffer = false;
779
780  // Try to determine if the main file has been remapped, either from the
781  // command line (to another file) or directly through the compiler invocation
782  // (to a memory buffer).
783  llvm::MemoryBuffer *Buffer = 0;
784  llvm::sys::PathWithStatus MainFilePath(FrontendOpts.Inputs[0].second);
785  if (const llvm::sys::FileStatus *MainFileStatus = MainFilePath.getFileStatus()) {
786    // Check whether there is a file-file remapping of the main file
787    for (PreprocessorOptions::remapped_file_iterator
788          M = PreprocessorOpts.remapped_file_begin(),
789          E = PreprocessorOpts.remapped_file_end();
790         M != E;
791         ++M) {
792      llvm::sys::PathWithStatus MPath(M->first);
793      if (const llvm::sys::FileStatus *MStatus = MPath.getFileStatus()) {
794        if (MainFileStatus->uniqueID == MStatus->uniqueID) {
795          // We found a remapping. Try to load the resulting, remapped source.
796          if (CreatedBuffer) {
797            delete Buffer;
798            CreatedBuffer = false;
799          }
800
801          Buffer = llvm::MemoryBuffer::getFile(M->second);
802          if (!Buffer)
803            return std::make_pair((llvm::MemoryBuffer*)0,
804                                  std::make_pair(0, true));
805          CreatedBuffer = true;
806
807          // Remove this remapping. We've captured the buffer already.
808          M = PreprocessorOpts.eraseRemappedFile(M);
809          E = PreprocessorOpts.remapped_file_end();
810        }
811      }
812    }
813
814    // Check whether there is a file-buffer remapping. It supercedes the
815    // file-file remapping.
816    for (PreprocessorOptions::remapped_file_buffer_iterator
817           M = PreprocessorOpts.remapped_file_buffer_begin(),
818           E = PreprocessorOpts.remapped_file_buffer_end();
819         M != E;
820         ++M) {
821      llvm::sys::PathWithStatus MPath(M->first);
822      if (const llvm::sys::FileStatus *MStatus = MPath.getFileStatus()) {
823        if (MainFileStatus->uniqueID == MStatus->uniqueID) {
824          // We found a remapping.
825          if (CreatedBuffer) {
826            delete Buffer;
827            CreatedBuffer = false;
828          }
829
830          Buffer = const_cast<llvm::MemoryBuffer *>(M->second);
831
832          // Remove this remapping. We've captured the buffer already.
833          M = PreprocessorOpts.eraseRemappedFile(M);
834          E = PreprocessorOpts.remapped_file_buffer_end();
835        }
836      }
837    }
838  }
839
840  // If the main source file was not remapped, load it now.
841  if (!Buffer) {
842    Buffer = llvm::MemoryBuffer::getFile(FrontendOpts.Inputs[0].second);
843    if (!Buffer)
844      return std::make_pair((llvm::MemoryBuffer*)0, std::make_pair(0, true));
845
846    CreatedBuffer = true;
847  }
848
849  return std::make_pair(Buffer, Lexer::ComputePreamble(Buffer, MaxLines));
850}
851
852static llvm::MemoryBuffer *CreatePaddedMainFileBuffer(llvm::MemoryBuffer *Old,
853                                                      bool DeleteOld,
854                                                      unsigned NewSize,
855                                                      llvm::StringRef NewName) {
856  llvm::MemoryBuffer *Result
857    = llvm::MemoryBuffer::getNewUninitMemBuffer(NewSize, NewName);
858  memcpy(const_cast<char*>(Result->getBufferStart()),
859         Old->getBufferStart(), Old->getBufferSize());
860  memset(const_cast<char*>(Result->getBufferStart()) + Old->getBufferSize(),
861         ' ', NewSize - Old->getBufferSize() - 1);
862  const_cast<char*>(Result->getBufferEnd())[-1] = '\n';
863
864  if (DeleteOld)
865    delete Old;
866
867  return Result;
868}
869
870/// \brief Attempt to build or re-use a precompiled preamble when (re-)parsing
871/// the source file.
872///
873/// This routine will compute the preamble of the main source file. If a
874/// non-trivial preamble is found, it will precompile that preamble into a
875/// precompiled header so that the precompiled preamble can be used to reduce
876/// reparsing time. If a precompiled preamble has already been constructed,
877/// this routine will determine if it is still valid and, if so, avoid
878/// rebuilding the precompiled preamble.
879///
880/// \param AllowRebuild When true (the default), this routine is
881/// allowed to rebuild the precompiled preamble if it is found to be
882/// out-of-date.
883///
884/// \param MaxLines When non-zero, the maximum number of lines that
885/// can occur within the preamble.
886///
887/// \returns If the precompiled preamble can be used, returns a newly-allocated
888/// buffer that should be used in place of the main file when doing so.
889/// Otherwise, returns a NULL pointer.
890llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
891                                                           bool AllowRebuild,
892                                                           unsigned MaxLines) {
893  CompilerInvocation PreambleInvocation(*Invocation);
894  FrontendOptions &FrontendOpts = PreambleInvocation.getFrontendOpts();
895  PreprocessorOptions &PreprocessorOpts
896    = PreambleInvocation.getPreprocessorOpts();
897
898  bool CreatedPreambleBuffer = false;
899  std::pair<llvm::MemoryBuffer *, std::pair<unsigned, bool> > NewPreamble
900    = ComputePreamble(PreambleInvocation, MaxLines, CreatedPreambleBuffer);
901
902  if (!NewPreamble.second.first) {
903    // We couldn't find a preamble in the main source. Clear out the current
904    // preamble, if we have one. It's obviously no good any more.
905    Preamble.clear();
906    if (!PreambleFile.empty()) {
907      llvm::sys::Path(PreambleFile).eraseFromDisk();
908      PreambleFile.clear();
909    }
910    if (CreatedPreambleBuffer)
911      delete NewPreamble.first;
912
913    // The next time we actually see a preamble, precompile it.
914    PreambleRebuildCounter = 1;
915    return 0;
916  }
917
918  if (!Preamble.empty()) {
919    // We've previously computed a preamble. Check whether we have the same
920    // preamble now that we did before, and that there's enough space in
921    // the main-file buffer within the precompiled preamble to fit the
922    // new main file.
923    if (Preamble.size() == NewPreamble.second.first &&
924        PreambleEndsAtStartOfLine == NewPreamble.second.second &&
925        NewPreamble.first->getBufferSize() < PreambleReservedSize-2 &&
926        memcmp(&Preamble[0], NewPreamble.first->getBufferStart(),
927               NewPreamble.second.first) == 0) {
928      // The preamble has not changed. We may be able to re-use the precompiled
929      // preamble.
930
931      // Check that none of the files used by the preamble have changed.
932      bool AnyFileChanged = false;
933
934      // First, make a record of those files that have been overridden via
935      // remapping or unsaved_files.
936      llvm::StringMap<std::pair<off_t, time_t> > OverriddenFiles;
937      for (PreprocessorOptions::remapped_file_iterator
938                R = PreprocessorOpts.remapped_file_begin(),
939             REnd = PreprocessorOpts.remapped_file_end();
940           !AnyFileChanged && R != REnd;
941           ++R) {
942        struct stat StatBuf;
943        if (stat(R->second.c_str(), &StatBuf)) {
944          // If we can't stat the file we're remapping to, assume that something
945          // horrible happened.
946          AnyFileChanged = true;
947          break;
948        }
949
950        OverriddenFiles[R->first] = std::make_pair(StatBuf.st_size,
951                                                   StatBuf.st_mtime);
952      }
953      for (PreprocessorOptions::remapped_file_buffer_iterator
954                R = PreprocessorOpts.remapped_file_buffer_begin(),
955             REnd = PreprocessorOpts.remapped_file_buffer_end();
956           !AnyFileChanged && R != REnd;
957           ++R) {
958        // FIXME: Should we actually compare the contents of file->buffer
959        // remappings?
960        OverriddenFiles[R->first] = std::make_pair(R->second->getBufferSize(),
961                                                   0);
962      }
963
964      // Check whether anything has changed.
965      for (llvm::StringMap<std::pair<off_t, time_t> >::iterator
966             F = FilesInPreamble.begin(), FEnd = FilesInPreamble.end();
967           !AnyFileChanged && F != FEnd;
968           ++F) {
969        llvm::StringMap<std::pair<off_t, time_t> >::iterator Overridden
970          = OverriddenFiles.find(F->first());
971        if (Overridden != OverriddenFiles.end()) {
972          // This file was remapped; check whether the newly-mapped file
973          // matches up with the previous mapping.
974          if (Overridden->second != F->second)
975            AnyFileChanged = true;
976          continue;
977        }
978
979        // The file was not remapped; check whether it has changed on disk.
980        struct stat StatBuf;
981        if (stat(F->first(), &StatBuf)) {
982          // If we can't stat the file, assume that something horrible happened.
983          AnyFileChanged = true;
984        } else if (StatBuf.st_size != F->second.first ||
985                   StatBuf.st_mtime != F->second.second)
986          AnyFileChanged = true;
987      }
988
989      if (!AnyFileChanged) {
990        // Okay! We can re-use the precompiled preamble.
991
992        // Set the state of the diagnostic object to mimic its state
993        // after parsing the preamble.
994        getDiagnostics().Reset();
995        getDiagnostics().setNumWarnings(NumWarningsInPreamble);
996        if (StoredDiagnostics.size() > NumStoredDiagnosticsInPreamble)
997          StoredDiagnostics.erase(
998            StoredDiagnostics.begin() + NumStoredDiagnosticsInPreamble,
999                                  StoredDiagnostics.end());
1000
1001        // Create a version of the main file buffer that is padded to
1002        // buffer size we reserved when creating the preamble.
1003        return CreatePaddedMainFileBuffer(NewPreamble.first,
1004                                          CreatedPreambleBuffer,
1005                                          PreambleReservedSize,
1006                                          FrontendOpts.Inputs[0].second);
1007      }
1008    }
1009
1010    // If we aren't allowed to rebuild the precompiled preamble, just
1011    // return now.
1012    if (!AllowRebuild)
1013      return 0;
1014
1015    // We can't reuse the previously-computed preamble. Build a new one.
1016    Preamble.clear();
1017    llvm::sys::Path(PreambleFile).eraseFromDisk();
1018    PreambleRebuildCounter = 1;
1019  } else if (!AllowRebuild) {
1020    // We aren't allowed to rebuild the precompiled preamble; just
1021    // return now.
1022    return 0;
1023  }
1024
1025  // If the preamble rebuild counter > 1, it's because we previously
1026  // failed to build a preamble and we're not yet ready to try
1027  // again. Decrement the counter and return a failure.
1028  if (PreambleRebuildCounter > 1) {
1029    --PreambleRebuildCounter;
1030    return 0;
1031  }
1032
1033  // We did not previously compute a preamble, or it can't be reused anyway.
1034  llvm::Timer *PreambleTimer = 0;
1035  if (TimerGroup.get()) {
1036    PreambleTimer = new llvm::Timer("Precompiling preamble", *TimerGroup);
1037    PreambleTimer->startTimer();
1038    Timers.push_back(PreambleTimer);
1039  }
1040
1041  // Create a new buffer that stores the preamble. The buffer also contains
1042  // extra space for the original contents of the file (which will be present
1043  // when we actually parse the file) along with more room in case the file
1044  // grows.
1045  PreambleReservedSize = NewPreamble.first->getBufferSize();
1046  if (PreambleReservedSize < 4096)
1047    PreambleReservedSize = 8191;
1048  else
1049    PreambleReservedSize *= 2;
1050
1051  // Save the preamble text for later; we'll need to compare against it for
1052  // subsequent reparses.
1053  Preamble.assign(NewPreamble.first->getBufferStart(),
1054                  NewPreamble.first->getBufferStart()
1055                                                  + NewPreamble.second.first);
1056  PreambleEndsAtStartOfLine = NewPreamble.second.second;
1057
1058  llvm::MemoryBuffer *PreambleBuffer
1059    = llvm::MemoryBuffer::getNewUninitMemBuffer(PreambleReservedSize,
1060                                                FrontendOpts.Inputs[0].second);
1061  memcpy(const_cast<char*>(PreambleBuffer->getBufferStart()),
1062         NewPreamble.first->getBufferStart(), Preamble.size());
1063  memset(const_cast<char*>(PreambleBuffer->getBufferStart()) + Preamble.size(),
1064         ' ', PreambleReservedSize - Preamble.size() - 1);
1065  const_cast<char*>(PreambleBuffer->getBufferEnd())[-1] = '\n';
1066
1067  // Remap the main source file to the preamble buffer.
1068  llvm::sys::PathWithStatus MainFilePath(FrontendOpts.Inputs[0].second);
1069  PreprocessorOpts.addRemappedFile(MainFilePath.str(), PreambleBuffer);
1070
1071  // Tell the compiler invocation to generate a temporary precompiled header.
1072  FrontendOpts.ProgramAction = frontend::GeneratePCH;
1073  // FIXME: Set ChainedPCH unconditionally, once it is ready.
1074  if (::getenv("LIBCLANG_CHAINING"))
1075    FrontendOpts.ChainedPCH = true;
1076  // FIXME: Generate the precompiled header into memory?
1077  FrontendOpts.OutputFile = GetPreamblePCHPath();
1078
1079  // Create the compiler instance to use for building the precompiled preamble.
1080  CompilerInstance Clang;
1081  Clang.setInvocation(&PreambleInvocation);
1082  OriginalSourceFile = Clang.getFrontendOpts().Inputs[0].second;
1083
1084  // Set up diagnostics, capturing all of the diagnostics produced.
1085  Clang.setDiagnostics(&getDiagnostics());
1086  CaptureDroppedDiagnostics Capture(CaptureDiagnostics,
1087                                    getDiagnostics(),
1088                                    StoredDiagnostics);
1089  Clang.setDiagnosticClient(getDiagnostics().getClient());
1090
1091  // Create the target instance.
1092  Clang.setTarget(TargetInfo::CreateTargetInfo(Clang.getDiagnostics(),
1093                                               Clang.getTargetOpts()));
1094  if (!Clang.hasTarget()) {
1095    Clang.takeDiagnosticClient();
1096    llvm::sys::Path(FrontendOpts.OutputFile).eraseFromDisk();
1097    Preamble.clear();
1098    if (CreatedPreambleBuffer)
1099      delete NewPreamble.first;
1100    if (PreambleTimer)
1101      PreambleTimer->stopTimer();
1102    PreambleRebuildCounter = DefaultPreambleRebuildInterval;
1103    return 0;
1104  }
1105
1106  // Inform the target of the language options.
1107  //
1108  // FIXME: We shouldn't need to do this, the target should be immutable once
1109  // created. This complexity should be lifted elsewhere.
1110  Clang.getTarget().setForcedLangOptions(Clang.getLangOpts());
1111
1112  assert(Clang.getFrontendOpts().Inputs.size() == 1 &&
1113         "Invocation must have exactly one source file!");
1114  assert(Clang.getFrontendOpts().Inputs[0].first != IK_AST &&
1115         "FIXME: AST inputs not yet supported here!");
1116  assert(Clang.getFrontendOpts().Inputs[0].first != IK_LLVM_IR &&
1117         "IR inputs not support here!");
1118
1119  // Clear out old caches and data.
1120  StoredDiagnostics.clear();
1121  TopLevelDecls.clear();
1122  TopLevelDeclsInPreamble.clear();
1123
1124  // Create a file manager object to provide access to and cache the filesystem.
1125  Clang.setFileManager(new FileManager);
1126
1127  // Create the source manager.
1128  Clang.setSourceManager(new SourceManager(getDiagnostics()));
1129
1130  llvm::OwningPtr<PrecompilePreambleAction> Act;
1131  Act.reset(new PrecompilePreambleAction(*this));
1132  if (!Act->BeginSourceFile(Clang, Clang.getFrontendOpts().Inputs[0].second,
1133                            Clang.getFrontendOpts().Inputs[0].first)) {
1134    Clang.takeDiagnosticClient();
1135    Clang.takeInvocation();
1136    llvm::sys::Path(FrontendOpts.OutputFile).eraseFromDisk();
1137    Preamble.clear();
1138    if (CreatedPreambleBuffer)
1139      delete NewPreamble.first;
1140    if (PreambleTimer)
1141      PreambleTimer->stopTimer();
1142    PreambleRebuildCounter = DefaultPreambleRebuildInterval;
1143
1144    return 0;
1145  }
1146
1147  Act->Execute();
1148  Act->EndSourceFile();
1149  Clang.takeDiagnosticClient();
1150  Clang.takeInvocation();
1151
1152  if (Diagnostics->hasErrorOccurred()) {
1153    // There were errors parsing the preamble, so no precompiled header was
1154    // generated. Forget that we even tried.
1155    // FIXME: Should we leave a note for ourselves to try again?
1156    llvm::sys::Path(FrontendOpts.OutputFile).eraseFromDisk();
1157    Preamble.clear();
1158    if (CreatedPreambleBuffer)
1159      delete NewPreamble.first;
1160    if (PreambleTimer)
1161      PreambleTimer->stopTimer();
1162    TopLevelDeclsInPreamble.clear();
1163    PreambleRebuildCounter = DefaultPreambleRebuildInterval;
1164    return 0;
1165  }
1166
1167  // Keep track of the preamble we precompiled.
1168  PreambleFile = FrontendOpts.OutputFile;
1169  NumStoredDiagnosticsInPreamble = StoredDiagnostics.size();
1170  NumWarningsInPreamble = getDiagnostics().getNumWarnings();
1171
1172  // Keep track of all of the files that the source manager knows about,
1173  // so we can verify whether they have changed or not.
1174  FilesInPreamble.clear();
1175  SourceManager &SourceMgr = Clang.getSourceManager();
1176  const llvm::MemoryBuffer *MainFileBuffer
1177    = SourceMgr.getBuffer(SourceMgr.getMainFileID());
1178  for (SourceManager::fileinfo_iterator F = SourceMgr.fileinfo_begin(),
1179                                     FEnd = SourceMgr.fileinfo_end();
1180       F != FEnd;
1181       ++F) {
1182    const FileEntry *File = F->second->Entry;
1183    if (!File || F->second->getRawBuffer() == MainFileBuffer)
1184      continue;
1185
1186    FilesInPreamble[File->getName()]
1187      = std::make_pair(F->second->getSize(), File->getModificationTime());
1188  }
1189
1190  if (PreambleTimer)
1191    PreambleTimer->stopTimer();
1192
1193  PreambleRebuildCounter = 1;
1194  return CreatePaddedMainFileBuffer(NewPreamble.first,
1195                                    CreatedPreambleBuffer,
1196                                    PreambleReservedSize,
1197                                    FrontendOpts.Inputs[0].second);
1198}
1199
1200void ASTUnit::RealizeTopLevelDeclsFromPreamble() {
1201  std::vector<Decl *> Resolved;
1202  Resolved.reserve(TopLevelDeclsInPreamble.size());
1203  ExternalASTSource &Source = *getASTContext().getExternalSource();
1204  for (unsigned I = 0, N = TopLevelDeclsInPreamble.size(); I != N; ++I) {
1205    // Resolve the declaration ID to an actual declaration, possibly
1206    // deserializing the declaration in the process.
1207    Decl *D = Source.GetExternalDecl(TopLevelDeclsInPreamble[I]);
1208    if (D)
1209      Resolved.push_back(D);
1210  }
1211  TopLevelDeclsInPreamble.clear();
1212  TopLevelDecls.insert(TopLevelDecls.begin(), Resolved.begin(), Resolved.end());
1213}
1214
1215unsigned ASTUnit::getMaxPCHLevel() const {
1216  if (!getOnlyLocalDecls())
1217    return Decl::MaxPCHLevel;
1218
1219  unsigned Result = 0;
1220  if (isMainFileAST() || SavedMainFileBuffer)
1221    ++Result;
1222  return Result;
1223}
1224
1225ASTUnit *ASTUnit::LoadFromCompilerInvocation(CompilerInvocation *CI,
1226                                   llvm::IntrusiveRefCntPtr<Diagnostic> Diags,
1227                                             bool OnlyLocalDecls,
1228                                             bool CaptureDiagnostics,
1229                                             bool PrecompilePreamble,
1230                                             bool CompleteTranslationUnit,
1231                                             bool CacheCodeCompletionResults) {
1232  if (!Diags.getPtr()) {
1233    // No diagnostics engine was provided, so create our own diagnostics object
1234    // with the default options.
1235    DiagnosticOptions DiagOpts;
1236    Diags = CompilerInstance::createDiagnostics(DiagOpts, 0, 0);
1237  }
1238
1239  // Create the AST unit.
1240  llvm::OwningPtr<ASTUnit> AST;
1241  AST.reset(new ASTUnit(false));
1242  AST->Diagnostics = Diags;
1243  AST->CaptureDiagnostics = CaptureDiagnostics;
1244  AST->OnlyLocalDecls = OnlyLocalDecls;
1245  AST->CompleteTranslationUnit = CompleteTranslationUnit;
1246  AST->ShouldCacheCodeCompletionResults = CacheCodeCompletionResults;
1247  AST->Invocation.reset(CI);
1248  CI->getPreprocessorOpts().RetainRemappedFileBuffers = true;
1249
1250  if (getenv("LIBCLANG_TIMING"))
1251    AST->TimerGroup.reset(
1252                  new llvm::TimerGroup(CI->getFrontendOpts().Inputs[0].second));
1253
1254
1255  llvm::MemoryBuffer *OverrideMainBuffer = 0;
1256  // FIXME: When C++ PCH is ready, allow use of it for a precompiled preamble.
1257  if (PrecompilePreamble && !CI->getLangOpts().CPlusPlus) {
1258    AST->PreambleRebuildCounter = 1;
1259    OverrideMainBuffer = AST->getMainBufferWithPrecompiledPreamble();
1260  }
1261
1262  llvm::Timer *ParsingTimer = 0;
1263  if (AST->TimerGroup.get()) {
1264    ParsingTimer = new llvm::Timer("Initial parse", *AST->TimerGroup);
1265    ParsingTimer->startTimer();
1266    AST->Timers.push_back(ParsingTimer);
1267  }
1268
1269  bool Failed = AST->Parse(OverrideMainBuffer);
1270  if (ParsingTimer)
1271    ParsingTimer->stopTimer();
1272
1273  return Failed? 0 : AST.take();
1274}
1275
1276ASTUnit *ASTUnit::LoadFromCommandLine(const char **ArgBegin,
1277                                      const char **ArgEnd,
1278                                    llvm::IntrusiveRefCntPtr<Diagnostic> Diags,
1279                                      llvm::StringRef ResourceFilesPath,
1280                                      bool OnlyLocalDecls,
1281                                      RemappedFile *RemappedFiles,
1282                                      unsigned NumRemappedFiles,
1283                                      bool CaptureDiagnostics,
1284                                      bool PrecompilePreamble,
1285                                      bool CompleteTranslationUnit,
1286                                      bool CacheCodeCompletionResults) {
1287  if (!Diags.getPtr()) {
1288    // No diagnostics engine was provided, so create our own diagnostics object
1289    // with the default options.
1290    DiagnosticOptions DiagOpts;
1291    Diags = CompilerInstance::createDiagnostics(DiagOpts, 0, 0);
1292  }
1293
1294  llvm::SmallVector<const char *, 16> Args;
1295  Args.push_back("<clang>"); // FIXME: Remove dummy argument.
1296  Args.insert(Args.end(), ArgBegin, ArgEnd);
1297
1298  // FIXME: Find a cleaner way to force the driver into restricted modes. We
1299  // also want to force it to use clang.
1300  Args.push_back("-fsyntax-only");
1301
1302  // FIXME: We shouldn't have to pass in the path info.
1303  driver::Driver TheDriver("clang", llvm::sys::getHostTriple(),
1304                           "a.out", false, false, *Diags);
1305
1306  // Don't check that inputs exist, they have been remapped.
1307  TheDriver.setCheckInputsExist(false);
1308
1309  llvm::OwningPtr<driver::Compilation> C(
1310    TheDriver.BuildCompilation(Args.size(), Args.data()));
1311
1312  // We expect to get back exactly one command job, if we didn't something
1313  // failed.
1314  const driver::JobList &Jobs = C->getJobs();
1315  if (Jobs.size() != 1 || !isa<driver::Command>(Jobs.begin())) {
1316    llvm::SmallString<256> Msg;
1317    llvm::raw_svector_ostream OS(Msg);
1318    C->PrintJob(OS, C->getJobs(), "; ", true);
1319    Diags->Report(diag::err_fe_expected_compiler_job) << OS.str();
1320    return 0;
1321  }
1322
1323  const driver::Command *Cmd = cast<driver::Command>(*Jobs.begin());
1324  if (llvm::StringRef(Cmd->getCreator().getName()) != "clang") {
1325    Diags->Report(diag::err_fe_expected_clang_command);
1326    return 0;
1327  }
1328
1329  const driver::ArgStringList &CCArgs = Cmd->getArguments();
1330  llvm::OwningPtr<CompilerInvocation> CI(new CompilerInvocation);
1331  CompilerInvocation::CreateFromArgs(*CI,
1332                                     const_cast<const char **>(CCArgs.data()),
1333                                     const_cast<const char **>(CCArgs.data()) +
1334                                     CCArgs.size(),
1335                                     *Diags);
1336
1337  // Override any files that need remapping
1338  for (unsigned I = 0; I != NumRemappedFiles; ++I)
1339    CI->getPreprocessorOpts().addRemappedFile(RemappedFiles[I].first,
1340                                              RemappedFiles[I].second);
1341
1342  // Override the resources path.
1343  CI->getHeaderSearchOpts().ResourceDir = ResourceFilesPath;
1344
1345  CI->getFrontendOpts().DisableFree = true;
1346  return LoadFromCompilerInvocation(CI.take(), Diags, OnlyLocalDecls,
1347                                    CaptureDiagnostics, PrecompilePreamble,
1348                                    CompleteTranslationUnit,
1349                                    CacheCodeCompletionResults);
1350}
1351
1352bool ASTUnit::Reparse(RemappedFile *RemappedFiles, unsigned NumRemappedFiles) {
1353  if (!Invocation.get())
1354    return true;
1355
1356  llvm::Timer *ReparsingTimer = 0;
1357  if (TimerGroup.get()) {
1358    ReparsingTimer = new llvm::Timer("Reparse", *TimerGroup);
1359    ReparsingTimer->startTimer();
1360    Timers.push_back(ReparsingTimer);
1361  }
1362
1363  // Remap files.
1364  Invocation->getPreprocessorOpts().clearRemappedFiles();
1365  for (unsigned I = 0; I != NumRemappedFiles; ++I)
1366    Invocation->getPreprocessorOpts().addRemappedFile(RemappedFiles[I].first,
1367                                                      RemappedFiles[I].second);
1368
1369  // If we have a preamble file lying around, or if we might try to
1370  // build a precompiled preamble, do so now.
1371  llvm::MemoryBuffer *OverrideMainBuffer = 0;
1372  if (!PreambleFile.empty() || PreambleRebuildCounter > 0)
1373    OverrideMainBuffer = getMainBufferWithPrecompiledPreamble();
1374
1375  // Clear out the diagnostics state.
1376  if (!OverrideMainBuffer)
1377    getDiagnostics().Reset();
1378
1379  // Parse the sources
1380  bool Result = Parse(OverrideMainBuffer);
1381  if (ReparsingTimer)
1382    ReparsingTimer->stopTimer();
1383  return Result;
1384}
1385
1386//----------------------------------------------------------------------------//
1387// Code completion
1388//----------------------------------------------------------------------------//
1389
1390namespace {
1391  /// \brief Code completion consumer that combines the cached code-completion
1392  /// results from an ASTUnit with the code-completion results provided to it,
1393  /// then passes the result on to
1394  class AugmentedCodeCompleteConsumer : public CodeCompleteConsumer {
1395    unsigned NormalContexts;
1396    ASTUnit &AST;
1397    CodeCompleteConsumer &Next;
1398
1399  public:
1400    AugmentedCodeCompleteConsumer(ASTUnit &AST, CodeCompleteConsumer &Next,
1401                                  bool IncludeMacros, bool IncludeCodePatterns,
1402                                  bool IncludeGlobals)
1403      : CodeCompleteConsumer(IncludeMacros, IncludeCodePatterns, IncludeGlobals,
1404                             Next.isOutputBinary()), AST(AST), Next(Next)
1405    {
1406      // Compute the set of contexts in which we will look when we don't have
1407      // any information about the specific context.
1408      NormalContexts
1409        = (1 << (CodeCompletionContext::CCC_TopLevel - 1))
1410        | (1 << (CodeCompletionContext::CCC_ObjCInterface - 1))
1411        | (1 << (CodeCompletionContext::CCC_ObjCImplementation - 1))
1412        | (1 << (CodeCompletionContext::CCC_ObjCIvarList - 1))
1413        | (1 << (CodeCompletionContext::CCC_Statement - 1))
1414        | (1 << (CodeCompletionContext::CCC_Expression - 1))
1415        | (1 << (CodeCompletionContext::CCC_ObjCMessageReceiver - 1))
1416        | (1 << (CodeCompletionContext::CCC_MemberAccess - 1))
1417        | (1 << (CodeCompletionContext::CCC_ObjCProtocolName - 1));
1418
1419      if (AST.getASTContext().getLangOptions().CPlusPlus)
1420        NormalContexts |= (1 << (CodeCompletionContext::CCC_EnumTag - 1))
1421                    | (1 << (CodeCompletionContext::CCC_UnionTag - 1))
1422                    | (1 << (CodeCompletionContext::CCC_ClassOrStructTag - 1));
1423    }
1424
1425    virtual void ProcessCodeCompleteResults(Sema &S,
1426                                            CodeCompletionContext Context,
1427                                            Result *Results,
1428                                            unsigned NumResults);
1429
1430    virtual void ProcessOverloadCandidates(Sema &S, unsigned CurrentArg,
1431                                           OverloadCandidate *Candidates,
1432                                           unsigned NumCandidates) {
1433      Next.ProcessOverloadCandidates(S, CurrentArg, Candidates, NumCandidates);
1434    }
1435  };
1436}
1437
1438/// \brief Helper function that computes which global names are hidden by the
1439/// local code-completion results.
1440void CalculateHiddenNames(const CodeCompletionContext &Context,
1441                          CodeCompleteConsumer::Result *Results,
1442                          unsigned NumResults,
1443                          ASTContext &Ctx,
1444                          llvm::StringSet<> &HiddenNames) {
1445  bool OnlyTagNames = false;
1446  switch (Context.getKind()) {
1447  case CodeCompletionContext::CCC_Other:
1448  case CodeCompletionContext::CCC_TopLevel:
1449  case CodeCompletionContext::CCC_ObjCInterface:
1450  case CodeCompletionContext::CCC_ObjCImplementation:
1451  case CodeCompletionContext::CCC_ObjCIvarList:
1452  case CodeCompletionContext::CCC_ClassStructUnion:
1453  case CodeCompletionContext::CCC_Statement:
1454  case CodeCompletionContext::CCC_Expression:
1455  case CodeCompletionContext::CCC_ObjCMessageReceiver:
1456  case CodeCompletionContext::CCC_MemberAccess:
1457  case CodeCompletionContext::CCC_Namespace:
1458  case CodeCompletionContext::CCC_Type:
1459    break;
1460
1461  case CodeCompletionContext::CCC_EnumTag:
1462  case CodeCompletionContext::CCC_UnionTag:
1463  case CodeCompletionContext::CCC_ClassOrStructTag:
1464    OnlyTagNames = true;
1465    break;
1466
1467  case CodeCompletionContext::CCC_ObjCProtocolName:
1468    // If we're just looking for protocol names, nothing can hide them.
1469    return;
1470  }
1471
1472  typedef CodeCompleteConsumer::Result Result;
1473  for (unsigned I = 0; I != NumResults; ++I) {
1474    if (Results[I].Kind != Result::RK_Declaration)
1475      continue;
1476
1477    unsigned IDNS
1478      = Results[I].Declaration->getUnderlyingDecl()->getIdentifierNamespace();
1479
1480    bool Hiding = false;
1481    if (OnlyTagNames)
1482      Hiding = (IDNS & Decl::IDNS_Tag);
1483    else {
1484      unsigned HiddenIDNS = (Decl::IDNS_Type | Decl::IDNS_Member |
1485                            Decl::IDNS_Namespace | Decl::IDNS_Ordinary |
1486                            Decl::IDNS_NonMemberOperator);
1487      if (Ctx.getLangOptions().CPlusPlus)
1488        HiddenIDNS |= Decl::IDNS_Tag;
1489      Hiding = (IDNS & HiddenIDNS);
1490    }
1491
1492    if (!Hiding)
1493      continue;
1494
1495    DeclarationName Name = Results[I].Declaration->getDeclName();
1496    if (IdentifierInfo *Identifier = Name.getAsIdentifierInfo())
1497      HiddenNames.insert(Identifier->getName());
1498    else
1499      HiddenNames.insert(Name.getAsString());
1500  }
1501}
1502
1503
1504void AugmentedCodeCompleteConsumer::ProcessCodeCompleteResults(Sema &S,
1505                                            CodeCompletionContext Context,
1506                                            Result *Results,
1507                                            unsigned NumResults) {
1508  // Merge the results we were given with the results we cached.
1509  bool AddedResult = false;
1510  unsigned InContexts
1511    = (Context.getKind() == CodeCompletionContext::CCC_Other? NormalContexts
1512                                            : (1 << (Context.getKind() - 1)));
1513
1514  // Contains the set of names that are hidden by "local" completion results.
1515  llvm::StringSet<> HiddenNames;
1516
1517  typedef CodeCompleteConsumer::Result Result;
1518  llvm::SmallVector<Result, 8> AllResults;
1519  for (ASTUnit::cached_completion_iterator
1520            C = AST.cached_completion_begin(),
1521         CEnd = AST.cached_completion_end();
1522       C != CEnd; ++C) {
1523    // If the context we are in matches any of the contexts we are
1524    // interested in, we'll add this result.
1525    if ((C->ShowInContexts & InContexts) == 0)
1526      continue;
1527
1528    // If we haven't added any results previously, do so now.
1529    if (!AddedResult) {
1530      CalculateHiddenNames(Context, Results, NumResults, S.Context,
1531                           HiddenNames);
1532      AllResults.insert(AllResults.end(), Results, Results + NumResults);
1533      AddedResult = true;
1534    }
1535
1536    // Determine whether this global completion result is hidden by a local
1537    // completion result. If so, skip it.
1538    if (C->Kind != CXCursor_MacroDefinition &&
1539        HiddenNames.count(C->Completion->getTypedText()))
1540      continue;
1541
1542    // Adjust priority based on similar type classes.
1543    unsigned Priority = C->Priority;
1544    if (!Context.getPreferredType().isNull()) {
1545      if (C->Kind == CXCursor_MacroDefinition) {
1546        Priority = getMacroUsagePriority(C->Completion->getTypedText(),
1547                               Context.getPreferredType()->isAnyPointerType());
1548      } else if (C->Type) {
1549        CanQualType Expected
1550          = S.Context.getCanonicalType(
1551                               Context.getPreferredType().getUnqualifiedType());
1552        SimplifiedTypeClass ExpectedSTC = getSimplifiedTypeClass(Expected);
1553        if (ExpectedSTC == C->TypeClass) {
1554          // We know this type is similar; check for an exact match.
1555          llvm::StringMap<unsigned> &CachedCompletionTypes
1556            = AST.getCachedCompletionTypes();
1557          llvm::StringMap<unsigned>::iterator Pos
1558            = CachedCompletionTypes.find(QualType(Expected).getAsString());
1559          if (Pos != CachedCompletionTypes.end() && Pos->second == C->Type)
1560            Priority /= CCF_ExactTypeMatch;
1561          else
1562            Priority /= CCF_SimilarTypeMatch;
1563        }
1564      }
1565    }
1566
1567    AllResults.push_back(Result(C->Completion, Priority, C->Kind));
1568  }
1569
1570  // If we did not add any cached completion results, just forward the
1571  // results we were given to the next consumer.
1572  if (!AddedResult) {
1573    Next.ProcessCodeCompleteResults(S, Context, Results, NumResults);
1574    return;
1575  }
1576
1577  Next.ProcessCodeCompleteResults(S, Context, AllResults.data(),
1578                                  AllResults.size());
1579}
1580
1581
1582
1583void ASTUnit::CodeComplete(llvm::StringRef File, unsigned Line, unsigned Column,
1584                           RemappedFile *RemappedFiles,
1585                           unsigned NumRemappedFiles,
1586                           bool IncludeMacros,
1587                           bool IncludeCodePatterns,
1588                           CodeCompleteConsumer &Consumer,
1589                           Diagnostic &Diag, LangOptions &LangOpts,
1590                           SourceManager &SourceMgr, FileManager &FileMgr,
1591                   llvm::SmallVectorImpl<StoredDiagnostic> &StoredDiagnostics) {
1592  if (!Invocation.get())
1593    return;
1594
1595  llvm::Timer *CompletionTimer = 0;
1596  if (TimerGroup.get()) {
1597    llvm::SmallString<128> TimerName;
1598    llvm::raw_svector_ostream TimerNameOut(TimerName);
1599    TimerNameOut << "Code completion @ " << File << ":" << Line << ":"
1600                 << Column;
1601    CompletionTimer = new llvm::Timer(TimerNameOut.str(), *TimerGroup);
1602    CompletionTimer->startTimer();
1603    Timers.push_back(CompletionTimer);
1604  }
1605
1606  CompilerInvocation CCInvocation(*Invocation);
1607  FrontendOptions &FrontendOpts = CCInvocation.getFrontendOpts();
1608  PreprocessorOptions &PreprocessorOpts = CCInvocation.getPreprocessorOpts();
1609
1610  FrontendOpts.ShowMacrosInCodeCompletion
1611    = IncludeMacros && CachedCompletionResults.empty();
1612  FrontendOpts.ShowCodePatternsInCodeCompletion = IncludeCodePatterns;
1613  FrontendOpts.ShowGlobalSymbolsInCodeCompletion
1614    = CachedCompletionResults.empty();
1615  FrontendOpts.CodeCompletionAt.FileName = File;
1616  FrontendOpts.CodeCompletionAt.Line = Line;
1617  FrontendOpts.CodeCompletionAt.Column = Column;
1618
1619  // Turn on spell-checking when performing code completion. It leads
1620  // to better results.
1621  unsigned SpellChecking = CCInvocation.getLangOpts().SpellChecking;
1622  CCInvocation.getLangOpts().SpellChecking = 1;
1623
1624  // Set the language options appropriately.
1625  LangOpts = CCInvocation.getLangOpts();
1626
1627  CompilerInstance Clang;
1628  Clang.setInvocation(&CCInvocation);
1629  OriginalSourceFile = Clang.getFrontendOpts().Inputs[0].second;
1630
1631  // Set up diagnostics, capturing any diagnostics produced.
1632  Clang.setDiagnostics(&Diag);
1633  CaptureDroppedDiagnostics Capture(true,
1634                                    Clang.getDiagnostics(),
1635                                    StoredDiagnostics);
1636  Clang.setDiagnosticClient(Diag.getClient());
1637
1638  // Create the target instance.
1639  Clang.setTarget(TargetInfo::CreateTargetInfo(Clang.getDiagnostics(),
1640                                               Clang.getTargetOpts()));
1641  if (!Clang.hasTarget()) {
1642    Clang.takeDiagnosticClient();
1643    Clang.takeInvocation();
1644  }
1645
1646  // Inform the target of the language options.
1647  //
1648  // FIXME: We shouldn't need to do this, the target should be immutable once
1649  // created. This complexity should be lifted elsewhere.
1650  Clang.getTarget().setForcedLangOptions(Clang.getLangOpts());
1651
1652  assert(Clang.getFrontendOpts().Inputs.size() == 1 &&
1653         "Invocation must have exactly one source file!");
1654  assert(Clang.getFrontendOpts().Inputs[0].first != IK_AST &&
1655         "FIXME: AST inputs not yet supported here!");
1656  assert(Clang.getFrontendOpts().Inputs[0].first != IK_LLVM_IR &&
1657         "IR inputs not support here!");
1658
1659
1660  // Use the source and file managers that we were given.
1661  Clang.setFileManager(&FileMgr);
1662  Clang.setSourceManager(&SourceMgr);
1663
1664  // Remap files.
1665  PreprocessorOpts.clearRemappedFiles();
1666  PreprocessorOpts.RetainRemappedFileBuffers = true;
1667  for (unsigned I = 0; I != NumRemappedFiles; ++I)
1668    PreprocessorOpts.addRemappedFile(RemappedFiles[I].first,
1669                                     RemappedFiles[I].second);
1670
1671  // Use the code completion consumer we were given, but adding any cached
1672  // code-completion results.
1673  AugmentedCodeCompleteConsumer
1674  AugmentedConsumer(*this, Consumer, FrontendOpts.ShowMacrosInCodeCompletion,
1675                    FrontendOpts.ShowCodePatternsInCodeCompletion,
1676                    FrontendOpts.ShowGlobalSymbolsInCodeCompletion);
1677  Clang.setCodeCompletionConsumer(&AugmentedConsumer);
1678
1679  // If we have a precompiled preamble, try to use it. We only allow
1680  // the use of the precompiled preamble if we're if the completion
1681  // point is within the main file, after the end of the precompiled
1682  // preamble.
1683  llvm::MemoryBuffer *OverrideMainBuffer = 0;
1684  if (!PreambleFile.empty()) {
1685    using llvm::sys::FileStatus;
1686    llvm::sys::PathWithStatus CompleteFilePath(File);
1687    llvm::sys::PathWithStatus MainPath(OriginalSourceFile);
1688    if (const FileStatus *CompleteFileStatus = CompleteFilePath.getFileStatus())
1689      if (const FileStatus *MainStatus = MainPath.getFileStatus())
1690        if (CompleteFileStatus->getUniqueID() == MainStatus->getUniqueID())
1691          OverrideMainBuffer = getMainBufferWithPrecompiledPreamble(false,
1692                                                                    Line);
1693  }
1694
1695  // If the main file has been overridden due to the use of a preamble,
1696  // make that override happen and introduce the preamble.
1697  if (OverrideMainBuffer) {
1698    PreprocessorOpts.addRemappedFile(OriginalSourceFile, OverrideMainBuffer);
1699    PreprocessorOpts.PrecompiledPreambleBytes.first = Preamble.size();
1700    PreprocessorOpts.PrecompiledPreambleBytes.second
1701                                                    = PreambleEndsAtStartOfLine;
1702    PreprocessorOpts.ImplicitPCHInclude = PreambleFile;
1703    PreprocessorOpts.DisablePCHValidation = true;
1704
1705    // The stored diagnostics have the old source manager. Copy them
1706    // to our output set of stored diagnostics, updating the source
1707    // manager to the one we were given.
1708    for (unsigned I = 0, N = this->StoredDiagnostics.size(); I != N; ++I) {
1709      StoredDiagnostics.push_back(this->StoredDiagnostics[I]);
1710      FullSourceLoc Loc(StoredDiagnostics[I].getLocation(), SourceMgr);
1711      StoredDiagnostics[I].setLocation(Loc);
1712    }
1713  }
1714
1715  llvm::OwningPtr<SyntaxOnlyAction> Act;
1716  Act.reset(new SyntaxOnlyAction);
1717  if (Act->BeginSourceFile(Clang, Clang.getFrontendOpts().Inputs[0].second,
1718                           Clang.getFrontendOpts().Inputs[0].first)) {
1719    Act->Execute();
1720    Act->EndSourceFile();
1721  }
1722
1723  if (CompletionTimer)
1724    CompletionTimer->stopTimer();
1725
1726  // Steal back our resources.
1727  delete OverrideMainBuffer;
1728  Clang.takeFileManager();
1729  Clang.takeSourceManager();
1730  Clang.takeInvocation();
1731  Clang.takeDiagnosticClient();
1732  Clang.takeCodeCompletionConsumer();
1733  CCInvocation.getLangOpts().SpellChecking = SpellChecking;
1734}
1735
1736bool ASTUnit::Save(llvm::StringRef File) {
1737  if (getDiagnostics().hasErrorOccurred())
1738    return true;
1739
1740  // FIXME: Can we somehow regenerate the stat cache here, or do we need to
1741  // unconditionally create a stat cache when we parse the file?
1742  std::string ErrorInfo;
1743  llvm::raw_fd_ostream Out(File.str().c_str(), ErrorInfo,
1744                           llvm::raw_fd_ostream::F_Binary);
1745  if (!ErrorInfo.empty() || Out.has_error())
1746    return true;
1747
1748  std::vector<unsigned char> Buffer;
1749  llvm::BitstreamWriter Stream(Buffer);
1750  PCHWriter Writer(Stream);
1751  Writer.WritePCH(getSema(), 0, 0);
1752
1753  // Write the generated bitstream to "Out".
1754  Out.write((char *)&Buffer.front(), Buffer.size());
1755  Out.close();
1756  return Out.has_error();
1757}
1758