xref: /llvm-project/clang/lib/Frontend/CompilerInstance.cpp (revision 963c5535649dc049547853ebd3ad33ea17d2ae04)
1 //===--- CompilerInstance.cpp ---------------------------------------------===//
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 #include "clang/Frontend/CompilerInstance.h"
11 #include "clang/AST/ASTConsumer.h"
12 #include "clang/AST/ASTContext.h"
13 #include "clang/AST/Decl.h"
14 #include "clang/Basic/Diagnostic.h"
15 #include "clang/Basic/FileManager.h"
16 #include "clang/Basic/SourceManager.h"
17 #include "clang/Basic/TargetInfo.h"
18 #include "clang/Basic/Version.h"
19 #include "clang/Frontend/ChainedDiagnosticConsumer.h"
20 #include "clang/Frontend/FrontendAction.h"
21 #include "clang/Frontend/FrontendActions.h"
22 #include "clang/Frontend/FrontendDiagnostic.h"
23 #include "clang/Frontend/LogDiagnosticPrinter.h"
24 #include "clang/Frontend/SerializedDiagnosticPrinter.h"
25 #include "clang/Frontend/TextDiagnosticPrinter.h"
26 #include "clang/Frontend/Utils.h"
27 #include "clang/Frontend/VerifyDiagnosticConsumer.h"
28 #include "clang/Lex/HeaderSearch.h"
29 #include "clang/Lex/PTHManager.h"
30 #include "clang/Lex/Preprocessor.h"
31 #include "clang/Sema/CodeCompleteConsumer.h"
32 #include "clang/Sema/Sema.h"
33 #include "clang/Serialization/ASTReader.h"
34 #include "llvm/ADT/Statistic.h"
35 #include "llvm/Config/config.h"
36 #include "llvm/Support/CrashRecoveryContext.h"
37 #include "llvm/Support/FileSystem.h"
38 #include "llvm/Support/Host.h"
39 #include "llvm/Support/LockFileManager.h"
40 #include "llvm/Support/MemoryBuffer.h"
41 #include "llvm/Support/Path.h"
42 #include "llvm/Support/PathV1.h"
43 #include "llvm/Support/Program.h"
44 #include "llvm/Support/Signals.h"
45 #include "llvm/Support/Timer.h"
46 #include "llvm/Support/raw_ostream.h"
47 #include "llvm/Support/system_error.h"
48 #include <sys/stat.h>
49 #include <time.h>
50 
51 using namespace clang;
52 
53 CompilerInstance::CompilerInstance()
54   : Invocation(new CompilerInvocation()), ModuleManager(0),
55     BuildGlobalModuleIndex(false), ModuleBuildFailed(false) {
56 }
57 
58 CompilerInstance::~CompilerInstance() {
59   assert(OutputFiles.empty() && "Still output files in flight?");
60 }
61 
62 void CompilerInstance::setInvocation(CompilerInvocation *Value) {
63   Invocation = Value;
64 }
65 
66 bool CompilerInstance::shouldBuildGlobalModuleIndex() const {
67   return (BuildGlobalModuleIndex ||
68           (ModuleManager && ModuleManager->isGlobalIndexUnavailable() &&
69            getFrontendOpts().GenerateGlobalModuleIndex)) &&
70          !ModuleBuildFailed;
71 }
72 
73 void CompilerInstance::setDiagnostics(DiagnosticsEngine *Value) {
74   Diagnostics = Value;
75 }
76 
77 void CompilerInstance::setTarget(TargetInfo *Value) {
78   Target = Value;
79 }
80 
81 void CompilerInstance::setFileManager(FileManager *Value) {
82   FileMgr = Value;
83 }
84 
85 void CompilerInstance::setSourceManager(SourceManager *Value) {
86   SourceMgr = Value;
87 }
88 
89 void CompilerInstance::setPreprocessor(Preprocessor *Value) { PP = Value; }
90 
91 void CompilerInstance::setASTContext(ASTContext *Value) { Context = Value; }
92 
93 void CompilerInstance::setSema(Sema *S) {
94   TheSema.reset(S);
95 }
96 
97 void CompilerInstance::setASTConsumer(ASTConsumer *Value) {
98   Consumer.reset(Value);
99 }
100 
101 void CompilerInstance::setCodeCompletionConsumer(CodeCompleteConsumer *Value) {
102   CompletionConsumer.reset(Value);
103 }
104 
105 // Diagnostics
106 static void SetUpDiagnosticLog(DiagnosticOptions *DiagOpts,
107                                const CodeGenOptions *CodeGenOpts,
108                                DiagnosticsEngine &Diags) {
109   std::string ErrorInfo;
110   bool OwnsStream = false;
111   raw_ostream *OS = &llvm::errs();
112   if (DiagOpts->DiagnosticLogFile != "-") {
113     // Create the output stream.
114     llvm::raw_fd_ostream *FileOS(
115       new llvm::raw_fd_ostream(DiagOpts->DiagnosticLogFile.c_str(),
116                                ErrorInfo, llvm::raw_fd_ostream::F_Append));
117     if (!ErrorInfo.empty()) {
118       Diags.Report(diag::warn_fe_cc_log_diagnostics_failure)
119         << DiagOpts->DiagnosticLogFile << ErrorInfo;
120     } else {
121       FileOS->SetUnbuffered();
122       FileOS->SetUseAtomicWrites(true);
123       OS = FileOS;
124       OwnsStream = true;
125     }
126   }
127 
128   // Chain in the diagnostic client which will log the diagnostics.
129   LogDiagnosticPrinter *Logger = new LogDiagnosticPrinter(*OS, DiagOpts,
130                                                           OwnsStream);
131   if (CodeGenOpts)
132     Logger->setDwarfDebugFlags(CodeGenOpts->DwarfDebugFlags);
133   Diags.setClient(new ChainedDiagnosticConsumer(Diags.takeClient(), Logger));
134 }
135 
136 static void SetupSerializedDiagnostics(DiagnosticOptions *DiagOpts,
137                                        DiagnosticsEngine &Diags,
138                                        StringRef OutputFile) {
139   std::string ErrorInfo;
140   OwningPtr<llvm::raw_fd_ostream> OS;
141   OS.reset(new llvm::raw_fd_ostream(OutputFile.str().c_str(), ErrorInfo,
142                                     llvm::raw_fd_ostream::F_Binary));
143 
144   if (!ErrorInfo.empty()) {
145     Diags.Report(diag::warn_fe_serialized_diag_failure)
146       << OutputFile << ErrorInfo;
147     return;
148   }
149 
150   DiagnosticConsumer *SerializedConsumer =
151     clang::serialized_diags::create(OS.take(), DiagOpts);
152 
153 
154   Diags.setClient(new ChainedDiagnosticConsumer(Diags.takeClient(),
155                                                 SerializedConsumer));
156 }
157 
158 void CompilerInstance::createDiagnostics(DiagnosticConsumer *Client,
159                                          bool ShouldOwnClient) {
160   Diagnostics = createDiagnostics(&getDiagnosticOpts(), Client,
161                                   ShouldOwnClient, &getCodeGenOpts());
162 }
163 
164 IntrusiveRefCntPtr<DiagnosticsEngine>
165 CompilerInstance::createDiagnostics(DiagnosticOptions *Opts,
166                                     DiagnosticConsumer *Client,
167                                     bool ShouldOwnClient,
168                                     const CodeGenOptions *CodeGenOpts) {
169   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
170   IntrusiveRefCntPtr<DiagnosticsEngine>
171       Diags(new DiagnosticsEngine(DiagID, Opts));
172 
173   // Create the diagnostic client for reporting errors or for
174   // implementing -verify.
175   if (Client) {
176     Diags->setClient(Client, ShouldOwnClient);
177   } else
178     Diags->setClient(new TextDiagnosticPrinter(llvm::errs(), Opts));
179 
180   // Chain in -verify checker, if requested.
181   if (Opts->VerifyDiagnostics)
182     Diags->setClient(new VerifyDiagnosticConsumer(*Diags));
183 
184   // Chain in -diagnostic-log-file dumper, if requested.
185   if (!Opts->DiagnosticLogFile.empty())
186     SetUpDiagnosticLog(Opts, CodeGenOpts, *Diags);
187 
188   if (!Opts->DiagnosticSerializationFile.empty())
189     SetupSerializedDiagnostics(Opts, *Diags,
190                                Opts->DiagnosticSerializationFile);
191 
192   // Configure our handling of diagnostics.
193   ProcessWarningOptions(*Diags, *Opts);
194 
195   return Diags;
196 }
197 
198 // File Manager
199 
200 void CompilerInstance::createFileManager() {
201   FileMgr = new FileManager(getFileSystemOpts());
202 }
203 
204 // Source Manager
205 
206 void CompilerInstance::createSourceManager(FileManager &FileMgr) {
207   SourceMgr = new SourceManager(getDiagnostics(), FileMgr);
208 }
209 
210 // Preprocessor
211 
212 void CompilerInstance::createPreprocessor() {
213   const PreprocessorOptions &PPOpts = getPreprocessorOpts();
214 
215   // Create a PTH manager if we are using some form of a token cache.
216   PTHManager *PTHMgr = 0;
217   if (!PPOpts.TokenCache.empty())
218     PTHMgr = PTHManager::Create(PPOpts.TokenCache, getDiagnostics());
219 
220   // Create the Preprocessor.
221   HeaderSearch *HeaderInfo = new HeaderSearch(&getHeaderSearchOpts(),
222                                               getFileManager(),
223                                               getDiagnostics(),
224                                               getLangOpts(),
225                                               &getTarget());
226   PP = new Preprocessor(&getPreprocessorOpts(),
227                         getDiagnostics(), getLangOpts(), &getTarget(),
228                         getSourceManager(), *HeaderInfo, *this, PTHMgr,
229                         /*OwnsHeaderSearch=*/true);
230 
231   // Note that this is different then passing PTHMgr to Preprocessor's ctor.
232   // That argument is used as the IdentifierInfoLookup argument to
233   // IdentifierTable's ctor.
234   if (PTHMgr) {
235     PTHMgr->setPreprocessor(&*PP);
236     PP->setPTHManager(PTHMgr);
237   }
238 
239   if (PPOpts.DetailedRecord)
240     PP->createPreprocessingRecord();
241 
242   InitializePreprocessor(*PP, PPOpts, getHeaderSearchOpts(), getFrontendOpts());
243 
244   PP->setPreprocessedOutput(getPreprocessorOutputOpts().ShowCPP);
245 
246   // Set up the module path, including the hash for the
247   // module-creation options.
248   SmallString<256> SpecificModuleCache(
249                            getHeaderSearchOpts().ModuleCachePath);
250   if (!getHeaderSearchOpts().DisableModuleHash)
251     llvm::sys::path::append(SpecificModuleCache,
252                             getInvocation().getModuleHash());
253   PP->getHeaderSearchInfo().setModuleCachePath(SpecificModuleCache);
254 
255   // Handle generating dependencies, if requested.
256   const DependencyOutputOptions &DepOpts = getDependencyOutputOpts();
257   if (!DepOpts.OutputFile.empty())
258     AttachDependencyFileGen(*PP, DepOpts);
259   if (!DepOpts.DOTOutputFile.empty())
260     AttachDependencyGraphGen(*PP, DepOpts.DOTOutputFile,
261                              getHeaderSearchOpts().Sysroot);
262 
263 
264   // Handle generating header include information, if requested.
265   if (DepOpts.ShowHeaderIncludes)
266     AttachHeaderIncludeGen(*PP);
267   if (!DepOpts.HeaderIncludeOutputFile.empty()) {
268     StringRef OutputPath = DepOpts.HeaderIncludeOutputFile;
269     if (OutputPath == "-")
270       OutputPath = "";
271     AttachHeaderIncludeGen(*PP, /*ShowAllHeaders=*/true, OutputPath,
272                            /*ShowDepth=*/false);
273   }
274 }
275 
276 // ASTContext
277 
278 void CompilerInstance::createASTContext() {
279   Preprocessor &PP = getPreprocessor();
280   Context = new ASTContext(getLangOpts(), PP.getSourceManager(),
281                            &getTarget(), PP.getIdentifierTable(),
282                            PP.getSelectorTable(), PP.getBuiltinInfo(),
283                            /*size_reserve=*/ 0);
284 }
285 
286 // ExternalASTSource
287 
288 void CompilerInstance::createPCHExternalASTSource(StringRef Path,
289                                                   bool DisablePCHValidation,
290                                                 bool AllowPCHWithCompilerErrors,
291                                                  void *DeserializationListener){
292   OwningPtr<ExternalASTSource> Source;
293   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
294   Source.reset(createPCHExternalASTSource(Path, getHeaderSearchOpts().Sysroot,
295                                           DisablePCHValidation,
296                                           AllowPCHWithCompilerErrors,
297                                           getPreprocessor(), getASTContext(),
298                                           DeserializationListener,
299                                           Preamble,
300                                        getFrontendOpts().UseGlobalModuleIndex));
301   ModuleManager = static_cast<ASTReader*>(Source.get());
302   getASTContext().setExternalSource(Source);
303 }
304 
305 ExternalASTSource *
306 CompilerInstance::createPCHExternalASTSource(StringRef Path,
307                                              const std::string &Sysroot,
308                                              bool DisablePCHValidation,
309                                              bool AllowPCHWithCompilerErrors,
310                                              Preprocessor &PP,
311                                              ASTContext &Context,
312                                              void *DeserializationListener,
313                                              bool Preamble,
314                                              bool UseGlobalModuleIndex) {
315   OwningPtr<ASTReader> Reader;
316   Reader.reset(new ASTReader(PP, Context,
317                              Sysroot.empty() ? "" : Sysroot.c_str(),
318                              DisablePCHValidation,
319                              AllowPCHWithCompilerErrors,
320                              UseGlobalModuleIndex));
321 
322   Reader->setDeserializationListener(
323             static_cast<ASTDeserializationListener *>(DeserializationListener));
324   switch (Reader->ReadAST(Path,
325                           Preamble ? serialization::MK_Preamble
326                                    : serialization::MK_PCH,
327                           SourceLocation(),
328                           ASTReader::ARR_None)) {
329   case ASTReader::Success:
330     // Set the predefines buffer as suggested by the PCH reader. Typically, the
331     // predefines buffer will be empty.
332     PP.setPredefines(Reader->getSuggestedPredefines());
333     return Reader.take();
334 
335   case ASTReader::Failure:
336     // Unrecoverable failure: don't even try to process the input file.
337     break;
338 
339   case ASTReader::Missing:
340   case ASTReader::OutOfDate:
341   case ASTReader::VersionMismatch:
342   case ASTReader::ConfigurationMismatch:
343   case ASTReader::HadErrors:
344     // No suitable PCH file could be found. Return an error.
345     break;
346   }
347 
348   return 0;
349 }
350 
351 // Code Completion
352 
353 static bool EnableCodeCompletion(Preprocessor &PP,
354                                  const std::string &Filename,
355                                  unsigned Line,
356                                  unsigned Column) {
357   // Tell the source manager to chop off the given file at a specific
358   // line and column.
359   const FileEntry *Entry = PP.getFileManager().getFile(Filename);
360   if (!Entry) {
361     PP.getDiagnostics().Report(diag::err_fe_invalid_code_complete_file)
362       << Filename;
363     return true;
364   }
365 
366   // Truncate the named file at the given line/column.
367   PP.SetCodeCompletionPoint(Entry, Line, Column);
368   return false;
369 }
370 
371 void CompilerInstance::createCodeCompletionConsumer() {
372   const ParsedSourceLocation &Loc = getFrontendOpts().CodeCompletionAt;
373   if (!CompletionConsumer) {
374     setCodeCompletionConsumer(
375       createCodeCompletionConsumer(getPreprocessor(),
376                                    Loc.FileName, Loc.Line, Loc.Column,
377                                    getFrontendOpts().CodeCompleteOpts,
378                                    llvm::outs()));
379     if (!CompletionConsumer)
380       return;
381   } else if (EnableCodeCompletion(getPreprocessor(), Loc.FileName,
382                                   Loc.Line, Loc.Column)) {
383     setCodeCompletionConsumer(0);
384     return;
385   }
386 
387   if (CompletionConsumer->isOutputBinary() &&
388       llvm::sys::ChangeStdoutToBinary()) {
389     getPreprocessor().getDiagnostics().Report(diag::err_fe_stdout_binary);
390     setCodeCompletionConsumer(0);
391   }
392 }
393 
394 void CompilerInstance::createFrontendTimer() {
395   FrontendTimer.reset(new llvm::Timer("Clang front-end timer"));
396 }
397 
398 CodeCompleteConsumer *
399 CompilerInstance::createCodeCompletionConsumer(Preprocessor &PP,
400                                                const std::string &Filename,
401                                                unsigned Line,
402                                                unsigned Column,
403                                                const CodeCompleteOptions &Opts,
404                                                raw_ostream &OS) {
405   if (EnableCodeCompletion(PP, Filename, Line, Column))
406     return 0;
407 
408   // Set up the creation routine for code-completion.
409   return new PrintingCodeCompleteConsumer(Opts, OS);
410 }
411 
412 void CompilerInstance::createSema(TranslationUnitKind TUKind,
413                                   CodeCompleteConsumer *CompletionConsumer) {
414   TheSema.reset(new Sema(getPreprocessor(), getASTContext(), getASTConsumer(),
415                          TUKind, CompletionConsumer));
416 }
417 
418 // Output Files
419 
420 void CompilerInstance::addOutputFile(const OutputFile &OutFile) {
421   assert(OutFile.OS && "Attempt to add empty stream to output list!");
422   OutputFiles.push_back(OutFile);
423 }
424 
425 void CompilerInstance::clearOutputFiles(bool EraseFiles) {
426   for (std::list<OutputFile>::iterator
427          it = OutputFiles.begin(), ie = OutputFiles.end(); it != ie; ++it) {
428     delete it->OS;
429     if (!it->TempFilename.empty()) {
430       if (EraseFiles) {
431         bool existed;
432         llvm::sys::fs::remove(it->TempFilename, existed);
433       } else {
434         SmallString<128> NewOutFile(it->Filename);
435 
436         // If '-working-directory' was passed, the output filename should be
437         // relative to that.
438         FileMgr->FixupRelativePath(NewOutFile);
439         if (llvm::error_code ec = llvm::sys::fs::rename(it->TempFilename,
440                                                         NewOutFile.str())) {
441           getDiagnostics().Report(diag::err_unable_to_rename_temp)
442             << it->TempFilename << it->Filename << ec.message();
443 
444           bool existed;
445           llvm::sys::fs::remove(it->TempFilename, existed);
446         }
447       }
448     } else if (!it->Filename.empty() && EraseFiles)
449       llvm::sys::Path(it->Filename).eraseFromDisk();
450 
451   }
452   OutputFiles.clear();
453 }
454 
455 llvm::raw_fd_ostream *
456 CompilerInstance::createDefaultOutputFile(bool Binary,
457                                           StringRef InFile,
458                                           StringRef Extension) {
459   return createOutputFile(getFrontendOpts().OutputFile, Binary,
460                           /*RemoveFileOnSignal=*/true, InFile, Extension,
461                           /*UseTemporary=*/true);
462 }
463 
464 llvm::raw_fd_ostream *
465 CompilerInstance::createOutputFile(StringRef OutputPath,
466                                    bool Binary, bool RemoveFileOnSignal,
467                                    StringRef InFile,
468                                    StringRef Extension,
469                                    bool UseTemporary,
470                                    bool CreateMissingDirectories) {
471   std::string Error, OutputPathName, TempPathName;
472   llvm::raw_fd_ostream *OS = createOutputFile(OutputPath, Error, Binary,
473                                               RemoveFileOnSignal,
474                                               InFile, Extension,
475                                               UseTemporary,
476                                               CreateMissingDirectories,
477                                               &OutputPathName,
478                                               &TempPathName);
479   if (!OS) {
480     getDiagnostics().Report(diag::err_fe_unable_to_open_output)
481       << OutputPath << Error;
482     return 0;
483   }
484 
485   // Add the output file -- but don't try to remove "-", since this means we are
486   // using stdin.
487   addOutputFile(OutputFile((OutputPathName != "-") ? OutputPathName : "",
488                 TempPathName, OS));
489 
490   return OS;
491 }
492 
493 llvm::raw_fd_ostream *
494 CompilerInstance::createOutputFile(StringRef OutputPath,
495                                    std::string &Error,
496                                    bool Binary,
497                                    bool RemoveFileOnSignal,
498                                    StringRef InFile,
499                                    StringRef Extension,
500                                    bool UseTemporary,
501                                    bool CreateMissingDirectories,
502                                    std::string *ResultPathName,
503                                    std::string *TempPathName) {
504   assert((!CreateMissingDirectories || UseTemporary) &&
505          "CreateMissingDirectories is only allowed when using temporary files");
506 
507   std::string OutFile, TempFile;
508   if (!OutputPath.empty()) {
509     OutFile = OutputPath;
510   } else if (InFile == "-") {
511     OutFile = "-";
512   } else if (!Extension.empty()) {
513     llvm::sys::Path Path(InFile);
514     Path.eraseSuffix();
515     Path.appendSuffix(Extension);
516     OutFile = Path.str();
517   } else {
518     OutFile = "-";
519   }
520 
521   OwningPtr<llvm::raw_fd_ostream> OS;
522   std::string OSFile;
523 
524   if (UseTemporary && OutFile != "-") {
525     // Only create the temporary if the parent directory exists (or create
526     // missing directories is true) and we can actually write to OutPath,
527     // otherwise we want to fail early.
528     SmallString<256> AbsPath(OutputPath);
529     llvm::sys::fs::make_absolute(AbsPath);
530     llvm::sys::Path OutPath(AbsPath);
531     bool ParentExists = false;
532     if (llvm::sys::fs::exists(llvm::sys::path::parent_path(AbsPath.str()),
533                               ParentExists))
534       ParentExists = false;
535     bool Exists;
536     if ((CreateMissingDirectories || ParentExists) &&
537         ((llvm::sys::fs::exists(AbsPath.str(), Exists) || !Exists) ||
538          (OutPath.isRegularFile() &&
539           llvm::sys::fs::can_write(AbsPath.c_str())))) {
540       // Create a temporary file.
541       SmallString<128> TempPath;
542       TempPath = OutFile;
543       TempPath += "-%%%%%%%%";
544       int fd;
545       if (llvm::sys::fs::unique_file(TempPath.str(), fd, TempPath,
546                                      /*makeAbsolute=*/false, 0664)
547           == llvm::errc::success) {
548         OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
549         OSFile = TempFile = TempPath.str();
550       }
551     }
552   }
553 
554   if (!OS) {
555     OSFile = OutFile;
556     OS.reset(
557       new llvm::raw_fd_ostream(OSFile.c_str(), Error,
558                                (Binary ? llvm::raw_fd_ostream::F_Binary : 0)));
559     if (!Error.empty())
560       return 0;
561   }
562 
563   // Make sure the out stream file gets removed if we crash.
564   if (RemoveFileOnSignal)
565     llvm::sys::RemoveFileOnSignal(OSFile);
566 
567   if (ResultPathName)
568     *ResultPathName = OutFile;
569   if (TempPathName)
570     *TempPathName = TempFile;
571 
572   return OS.take();
573 }
574 
575 // Initialization Utilities
576 
577 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input){
578   return InitializeSourceManager(Input, getDiagnostics(),
579                                  getFileManager(), getSourceManager(),
580                                  getFrontendOpts());
581 }
582 
583 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input,
584                                                DiagnosticsEngine &Diags,
585                                                FileManager &FileMgr,
586                                                SourceManager &SourceMgr,
587                                                const FrontendOptions &Opts) {
588   SrcMgr::CharacteristicKind
589     Kind = Input.isSystem() ? SrcMgr::C_System : SrcMgr::C_User;
590 
591   if (Input.isBuffer()) {
592     SourceMgr.createMainFileIDForMemBuffer(Input.getBuffer(), Kind);
593     assert(!SourceMgr.getMainFileID().isInvalid() &&
594            "Couldn't establish MainFileID!");
595     return true;
596   }
597 
598   StringRef InputFile = Input.getFile();
599 
600   // Figure out where to get and map in the main file.
601   if (InputFile != "-") {
602     const FileEntry *File = FileMgr.getFile(InputFile);
603     if (!File) {
604       Diags.Report(diag::err_fe_error_reading) << InputFile;
605       return false;
606     }
607 
608     // The natural SourceManager infrastructure can't currently handle named
609     // pipes, but we would at least like to accept them for the main
610     // file. Detect them here, read them with the more generic MemoryBuffer
611     // function, and simply override their contents as we do for STDIN.
612     if (File->isNamedPipe()) {
613       OwningPtr<llvm::MemoryBuffer> MB;
614       if (llvm::error_code ec = llvm::MemoryBuffer::getFile(InputFile, MB)) {
615         Diags.Report(diag::err_cannot_open_file) << InputFile << ec.message();
616         return false;
617       }
618 
619       // Create a new virtual file that will have the correct size.
620       File = FileMgr.getVirtualFile(InputFile, MB->getBufferSize(), 0);
621       SourceMgr.overrideFileContents(File, MB.take());
622     }
623 
624     SourceMgr.createMainFileID(File, Kind);
625   } else {
626     OwningPtr<llvm::MemoryBuffer> SB;
627     if (llvm::MemoryBuffer::getSTDIN(SB)) {
628       // FIXME: Give ec.message() in this diag.
629       Diags.Report(diag::err_fe_error_reading_stdin);
630       return false;
631     }
632     const FileEntry *File = FileMgr.getVirtualFile(SB->getBufferIdentifier(),
633                                                    SB->getBufferSize(), 0);
634     SourceMgr.createMainFileID(File, Kind);
635     SourceMgr.overrideFileContents(File, SB.take());
636   }
637 
638   assert(!SourceMgr.getMainFileID().isInvalid() &&
639          "Couldn't establish MainFileID!");
640   return true;
641 }
642 
643 // High-Level Operations
644 
645 bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
646   assert(hasDiagnostics() && "Diagnostics engine is not initialized!");
647   assert(!getFrontendOpts().ShowHelp && "Client must handle '-help'!");
648   assert(!getFrontendOpts().ShowVersion && "Client must handle '-version'!");
649 
650   // FIXME: Take this as an argument, once all the APIs we used have moved to
651   // taking it as an input instead of hard-coding llvm::errs.
652   raw_ostream &OS = llvm::errs();
653 
654   // Create the target instance.
655   setTarget(TargetInfo::CreateTargetInfo(getDiagnostics(), &getTargetOpts()));
656   if (!hasTarget())
657     return false;
658 
659   // Inform the target of the language options.
660   //
661   // FIXME: We shouldn't need to do this, the target should be immutable once
662   // created. This complexity should be lifted elsewhere.
663   getTarget().setForcedLangOptions(getLangOpts());
664 
665   // rewriter project will change target built-in bool type from its default.
666   if (getFrontendOpts().ProgramAction == frontend::RewriteObjC)
667     getTarget().noSignedCharForObjCBool();
668 
669   // Validate/process some options.
670   if (getHeaderSearchOpts().Verbose)
671     OS << "clang -cc1 version " CLANG_VERSION_STRING
672        << " based upon " << PACKAGE_STRING
673        << " default target " << llvm::sys::getDefaultTargetTriple() << "\n";
674 
675   if (getFrontendOpts().ShowTimers)
676     createFrontendTimer();
677 
678   if (getFrontendOpts().ShowStats)
679     llvm::EnableStatistics();
680 
681   for (unsigned i = 0, e = getFrontendOpts().Inputs.size(); i != e; ++i) {
682     // Reset the ID tables if we are reusing the SourceManager.
683     if (hasSourceManager())
684       getSourceManager().clearIDTables();
685 
686     if (Act.BeginSourceFile(*this, getFrontendOpts().Inputs[i])) {
687       Act.Execute();
688       Act.EndSourceFile();
689     }
690   }
691 
692   // Notify the diagnostic client that all files were processed.
693   getDiagnostics().getClient()->finish();
694 
695   if (getDiagnosticOpts().ShowCarets) {
696     // We can have multiple diagnostics sharing one diagnostic client.
697     // Get the total number of warnings/errors from the client.
698     unsigned NumWarnings = getDiagnostics().getClient()->getNumWarnings();
699     unsigned NumErrors = getDiagnostics().getClient()->getNumErrors();
700 
701     if (NumWarnings)
702       OS << NumWarnings << " warning" << (NumWarnings == 1 ? "" : "s");
703     if (NumWarnings && NumErrors)
704       OS << " and ";
705     if (NumErrors)
706       OS << NumErrors << " error" << (NumErrors == 1 ? "" : "s");
707     if (NumWarnings || NumErrors)
708       OS << " generated.\n";
709   }
710 
711   if (getFrontendOpts().ShowStats && hasFileManager()) {
712     getFileManager().PrintStats();
713     OS << "\n";
714   }
715 
716   return !getDiagnostics().getClient()->getNumErrors();
717 }
718 
719 /// \brief Determine the appropriate source input kind based on language
720 /// options.
721 static InputKind getSourceInputKindFromOptions(const LangOptions &LangOpts) {
722   if (LangOpts.OpenCL)
723     return IK_OpenCL;
724   if (LangOpts.CUDA)
725     return IK_CUDA;
726   if (LangOpts.ObjC1)
727     return LangOpts.CPlusPlus? IK_ObjCXX : IK_ObjC;
728   return LangOpts.CPlusPlus? IK_CXX : IK_C;
729 }
730 
731 namespace {
732   struct CompileModuleMapData {
733     CompilerInstance &Instance;
734     GenerateModuleAction &CreateModuleAction;
735   };
736 }
737 
738 /// \brief Helper function that executes the module-generating action under
739 /// a crash recovery context.
740 static void doCompileMapModule(void *UserData) {
741   CompileModuleMapData &Data
742     = *reinterpret_cast<CompileModuleMapData *>(UserData);
743   Data.Instance.ExecuteAction(Data.CreateModuleAction);
744 }
745 
746 namespace {
747   /// \brief Function object that checks with the given macro definition should
748   /// be removed, because it is one of the ignored macros.
749   class RemoveIgnoredMacro {
750     const HeaderSearchOptions &HSOpts;
751 
752   public:
753     explicit RemoveIgnoredMacro(const HeaderSearchOptions &HSOpts)
754       : HSOpts(HSOpts) { }
755 
756     bool operator()(const std::pair<std::string, bool> &def) const {
757       StringRef MacroDef = def.first;
758       return HSOpts.ModulesIgnoreMacros.count(MacroDef.split('=').first) > 0;
759     }
760   };
761 }
762 
763 /// \brief Compile a module file for the given module, using the options
764 /// provided by the importing compiler instance.
765 static void compileModule(CompilerInstance &ImportingInstance,
766                           SourceLocation ImportLoc,
767                           Module *Module,
768                           StringRef ModuleFileName) {
769   llvm::LockFileManager Locked(ModuleFileName);
770   switch (Locked) {
771   case llvm::LockFileManager::LFS_Error:
772     return;
773 
774   case llvm::LockFileManager::LFS_Owned:
775     // We're responsible for building the module ourselves. Do so below.
776     break;
777 
778   case llvm::LockFileManager::LFS_Shared:
779     // Someone else is responsible for building the module. Wait for them to
780     // finish.
781     Locked.waitForUnlock();
782     return;
783   }
784 
785   ModuleMap &ModMap
786     = ImportingInstance.getPreprocessor().getHeaderSearchInfo().getModuleMap();
787 
788   // Construct a compiler invocation for creating this module.
789   IntrusiveRefCntPtr<CompilerInvocation> Invocation
790     (new CompilerInvocation(ImportingInstance.getInvocation()));
791 
792   PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
793 
794   // For any options that aren't intended to affect how a module is built,
795   // reset them to their default values.
796   Invocation->getLangOpts()->resetNonModularOptions();
797   PPOpts.resetNonModularOptions();
798 
799   // Remove any macro definitions that are explicitly ignored by the module.
800   // They aren't supposed to affect how the module is built anyway.
801   const HeaderSearchOptions &HSOpts = Invocation->getHeaderSearchOpts();
802   PPOpts.Macros.erase(std::remove_if(PPOpts.Macros.begin(), PPOpts.Macros.end(),
803                                      RemoveIgnoredMacro(HSOpts)),
804                       PPOpts.Macros.end());
805 
806 
807   // Note the name of the module we're building.
808   Invocation->getLangOpts()->CurrentModule = Module->getTopLevelModuleName();
809 
810   // Make sure that the failed-module structure has been allocated in
811   // the importing instance, and propagate the pointer to the newly-created
812   // instance.
813   PreprocessorOptions &ImportingPPOpts
814     = ImportingInstance.getInvocation().getPreprocessorOpts();
815   if (!ImportingPPOpts.FailedModules)
816     ImportingPPOpts.FailedModules = new PreprocessorOptions::FailedModulesSet;
817   PPOpts.FailedModules = ImportingPPOpts.FailedModules;
818 
819   // If there is a module map file, build the module using the module map.
820   // Set up the inputs/outputs so that we build the module from its umbrella
821   // header.
822   FrontendOptions &FrontendOpts = Invocation->getFrontendOpts();
823   FrontendOpts.OutputFile = ModuleFileName.str();
824   FrontendOpts.DisableFree = false;
825   FrontendOpts.GenerateGlobalModuleIndex = false;
826   FrontendOpts.Inputs.clear();
827   InputKind IK = getSourceInputKindFromOptions(*Invocation->getLangOpts());
828 
829   // Get or create the module map that we'll use to build this module.
830   SmallString<128> TempModuleMapFileName;
831   if (const FileEntry *ModuleMapFile
832                                   = ModMap.getContainingModuleMapFile(Module)) {
833     // Use the module map where this module resides.
834     FrontendOpts.Inputs.push_back(FrontendInputFile(ModuleMapFile->getName(),
835                                                     IK));
836   } else {
837     // Create a temporary module map file.
838     TempModuleMapFileName = Module->Name;
839     TempModuleMapFileName += "-%%%%%%%%.map";
840     int FD;
841     if (llvm::sys::fs::unique_file(TempModuleMapFileName.str(), FD,
842                                    TempModuleMapFileName,
843                                    /*makeAbsolute=*/true)
844           != llvm::errc::success) {
845       ImportingInstance.getDiagnostics().Report(diag::err_module_map_temp_file)
846         << TempModuleMapFileName;
847       return;
848     }
849     // Print the module map to this file.
850     llvm::raw_fd_ostream OS(FD, /*shouldClose=*/true);
851     Module->print(OS);
852     FrontendOpts.Inputs.push_back(
853       FrontendInputFile(TempModuleMapFileName.str().str(), IK));
854   }
855 
856   // Don't free the remapped file buffers; they are owned by our caller.
857   PPOpts.RetainRemappedFileBuffers = true;
858 
859   Invocation->getDiagnosticOpts().VerifyDiagnostics = 0;
860   assert(ImportingInstance.getInvocation().getModuleHash() ==
861          Invocation->getModuleHash() && "Module hash mismatch!");
862 
863   // Construct a compiler instance that will be used to actually create the
864   // module.
865   CompilerInstance Instance;
866   Instance.setInvocation(&*Invocation);
867 
868   Instance.createDiagnostics(new ForwardingDiagnosticConsumer(
869                                    ImportingInstance.getDiagnosticClient()),
870                              /*ShouldOwnClient=*/true);
871 
872   // Note that this module is part of the module build stack, so that we
873   // can detect cycles in the module graph.
874   Instance.createFileManager(); // FIXME: Adopt file manager from importer?
875   Instance.createSourceManager(Instance.getFileManager());
876   SourceManager &SourceMgr = Instance.getSourceManager();
877   SourceMgr.setModuleBuildStack(
878     ImportingInstance.getSourceManager().getModuleBuildStack());
879   SourceMgr.pushModuleBuildStack(Module->getTopLevelModuleName(),
880     FullSourceLoc(ImportLoc, ImportingInstance.getSourceManager()));
881 
882 
883   // Construct a module-generating action.
884   GenerateModuleAction CreateModuleAction(Module->IsSystem);
885 
886   // Execute the action to actually build the module in-place. Use a separate
887   // thread so that we get a stack large enough.
888   const unsigned ThreadStackSize = 8 << 20;
889   llvm::CrashRecoveryContext CRC;
890   CompileModuleMapData Data = { Instance, CreateModuleAction };
891   CRC.RunSafelyOnThread(&doCompileMapModule, &Data, ThreadStackSize);
892 
893 
894   // Delete the temporary module map file.
895   // FIXME: Even though we're executing under crash protection, it would still
896   // be nice to do this with RemoveFileOnSignal when we can. However, that
897   // doesn't make sense for all clients, so clean this up manually.
898   Instance.clearOutputFiles(/*EraseFiles=*/true);
899   if (!TempModuleMapFileName.empty())
900     llvm::sys::Path(TempModuleMapFileName).eraseFromDisk();
901 
902   // We've rebuilt a module. If we're allowed to generate or update the global
903   // module index, record that fact in the importing compiler instance.
904   if (ImportingInstance.getFrontendOpts().GenerateGlobalModuleIndex) {
905     ImportingInstance.setBuildGlobalModuleIndex(true);
906   }
907 }
908 
909 /// \brief Diagnose differences between the current definition of the given
910 /// configuration macro and the definition provided on the command line.
911 static void checkConfigMacro(Preprocessor &PP, StringRef ConfigMacro,
912                              Module *Mod, SourceLocation ImportLoc) {
913   IdentifierInfo *Id = PP.getIdentifierInfo(ConfigMacro);
914   SourceManager &SourceMgr = PP.getSourceManager();
915 
916   // If this identifier has never had a macro definition, then it could
917   // not have changed.
918   if (!Id->hadMacroDefinition())
919     return;
920 
921   // If this identifier does not currently have a macro definition,
922   // check whether it had one on the command line.
923   if (!Id->hasMacroDefinition()) {
924     MacroDirective::DefInfo LatestDef =
925         PP.getMacroDirectiveHistory(Id)->getDefinition();
926     for (MacroDirective::DefInfo Def = LatestDef; Def;
927            Def = Def.getPreviousDefinition()) {
928       FileID FID = SourceMgr.getFileID(Def.getLocation());
929       if (FID.isInvalid())
930         continue;
931 
932       // We only care about the predefines buffer.
933       if (FID != PP.getPredefinesFileID())
934         continue;
935 
936       // This macro was defined on the command line, then #undef'd later.
937       // Complain.
938       PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
939         << true << ConfigMacro << Mod->getFullModuleName();
940       if (LatestDef.isUndefined())
941         PP.Diag(LatestDef.getUndefLocation(), diag::note_module_def_undef_here)
942           << true;
943       return;
944     }
945 
946     // Okay: no definition in the predefines buffer.
947     return;
948   }
949 
950   // This identifier has a macro definition. Check whether we had a definition
951   // on the command line.
952   MacroDirective::DefInfo LatestDef =
953       PP.getMacroDirectiveHistory(Id)->getDefinition();
954   MacroDirective::DefInfo PredefinedDef;
955   for (MacroDirective::DefInfo Def = LatestDef; Def;
956          Def = Def.getPreviousDefinition()) {
957     FileID FID = SourceMgr.getFileID(Def.getLocation());
958     if (FID.isInvalid())
959       continue;
960 
961     // We only care about the predefines buffer.
962     if (FID != PP.getPredefinesFileID())
963       continue;
964 
965     PredefinedDef = Def;
966     break;
967   }
968 
969   // If there was no definition for this macro in the predefines buffer,
970   // complain.
971   if (!PredefinedDef ||
972       (!PredefinedDef.getLocation().isValid() &&
973        PredefinedDef.getUndefLocation().isValid())) {
974     PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
975       << false << ConfigMacro << Mod->getFullModuleName();
976     PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
977       << false;
978     return;
979   }
980 
981   // If the current macro definition is the same as the predefined macro
982   // definition, it's okay.
983   if (LatestDef.getMacroInfo() == PredefinedDef.getMacroInfo() ||
984       LatestDef.getMacroInfo()->isIdenticalTo(*PredefinedDef.getMacroInfo(),PP,
985                                               /*Syntactically=*/true))
986     return;
987 
988   // The macro definitions differ.
989   PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
990     << false << ConfigMacro << Mod->getFullModuleName();
991   PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
992     << false;
993 }
994 
995 /// \brief Write a new timestamp file with the given path.
996 static void writeTimestampFile(StringRef TimestampFile) {
997   std::string ErrorInfo;
998   llvm::raw_fd_ostream Out(TimestampFile.str().c_str(), ErrorInfo,
999                            llvm::raw_fd_ostream::F_Binary);
1000 }
1001 
1002 /// \brief Prune the module cache of modules that haven't been accessed in
1003 /// a long time.
1004 static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
1005   struct stat StatBuf;
1006   llvm::SmallString<128> TimestampFile;
1007   TimestampFile = HSOpts.ModuleCachePath;
1008   llvm::sys::path::append(TimestampFile, "modules.timestamp");
1009 
1010   // Try to stat() the timestamp file.
1011   if (::stat(TimestampFile.c_str(), &StatBuf)) {
1012     // If the timestamp file wasn't there, create one now.
1013     if (errno == ENOENT) {
1014       writeTimestampFile(TimestampFile);
1015     }
1016     return;
1017   }
1018 
1019   // Check whether the time stamp is older than our pruning interval.
1020   // If not, do nothing.
1021   time_t TimeStampModTime = StatBuf.st_mtime;
1022   time_t CurrentTime = time(0);
1023   if (CurrentTime - TimeStampModTime <= time_t(HSOpts.ModuleCachePruneInterval))
1024     return;
1025 
1026   // Write a new timestamp file so that nobody else attempts to prune.
1027   // There is a benign race condition here, if two Clang instances happen to
1028   // notice at the same time that the timestamp is out-of-date.
1029   writeTimestampFile(TimestampFile);
1030 
1031   // Walk the entire module cache, looking for unused module files and module
1032   // indices.
1033   llvm::error_code EC;
1034   SmallString<128> ModuleCachePathNative;
1035   llvm::sys::path::native(HSOpts.ModuleCachePath, ModuleCachePathNative);
1036   for (llvm::sys::fs::directory_iterator
1037          Dir(ModuleCachePathNative.str(), EC), DirEnd;
1038        Dir != DirEnd && !EC; Dir.increment(EC)) {
1039     // If we don't have a directory, there's nothing to look into.
1040     bool IsDirectory;
1041     if (llvm::sys::fs::is_directory(Dir->path(), IsDirectory) || !IsDirectory)
1042       continue;
1043 
1044     // Walk all of the files within this directory.
1045     bool RemovedAllFiles = true;
1046     for (llvm::sys::fs::directory_iterator File(Dir->path(), EC), FileEnd;
1047          File != FileEnd && !EC; File.increment(EC)) {
1048       // We only care about module and global module index files.
1049       if (llvm::sys::path::extension(File->path()) != ".pcm" &&
1050           llvm::sys::path::filename(File->path()) != "modules.idx") {
1051         RemovedAllFiles = false;
1052         continue;
1053       }
1054 
1055       // Look at this file. If we can't stat it, there's nothing interesting
1056       // there.
1057       if (::stat(File->path().c_str(), &StatBuf)) {
1058         RemovedAllFiles = false;
1059         continue;
1060       }
1061 
1062       // If the file has been used recently enough, leave it there.
1063       time_t FileAccessTime = StatBuf.st_atime;
1064       if (CurrentTime - FileAccessTime <=
1065               time_t(HSOpts.ModuleCachePruneAfter)) {
1066         RemovedAllFiles = false;
1067         continue;
1068       }
1069 
1070       // Remove the file.
1071       bool Existed;
1072       if (llvm::sys::fs::remove(File->path(), Existed) || !Existed) {
1073         RemovedAllFiles = false;
1074       }
1075     }
1076 
1077     // If we removed all of the files in the directory, remove the directory
1078     // itself.
1079     if (RemovedAllFiles) {
1080       bool Existed;
1081       llvm::sys::fs::remove(Dir->path(), Existed);
1082     }
1083   }
1084 }
1085 
1086 ModuleLoadResult
1087 CompilerInstance::loadModule(SourceLocation ImportLoc,
1088                              ModuleIdPath Path,
1089                              Module::NameVisibilityKind Visibility,
1090                              bool IsInclusionDirective) {
1091   // If we've already handled this import, just return the cached result.
1092   // This one-element cache is important to eliminate redundant diagnostics
1093   // when both the preprocessor and parser see the same import declaration.
1094   if (!ImportLoc.isInvalid() && LastModuleImportLoc == ImportLoc) {
1095     // Make the named module visible.
1096     if (LastModuleImportResult)
1097       ModuleManager->makeModuleVisible(LastModuleImportResult, Visibility,
1098                                        ImportLoc, /*Complain=*/false);
1099     return LastModuleImportResult;
1100   }
1101 
1102   // Determine what file we're searching from.
1103   StringRef ModuleName = Path[0].first->getName();
1104   SourceLocation ModuleNameLoc = Path[0].second;
1105 
1106   clang::Module *Module = 0;
1107 
1108   // If we don't already have information on this module, load the module now.
1109   llvm::DenseMap<const IdentifierInfo *, clang::Module *>::iterator Known
1110     = KnownModules.find(Path[0].first);
1111   if (Known != KnownModules.end()) {
1112     // Retrieve the cached top-level module.
1113     Module = Known->second;
1114   } else if (ModuleName == getLangOpts().CurrentModule) {
1115     // This is the module we're building.
1116     Module = PP->getHeaderSearchInfo().getModuleMap().findModule(ModuleName);
1117     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1118   } else {
1119     // Search for a module with the given name.
1120     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
1121     std::string ModuleFileName;
1122     if (Module) {
1123       ModuleFileName = PP->getHeaderSearchInfo().getModuleFileName(Module);
1124     } else
1125       ModuleFileName = PP->getHeaderSearchInfo().getModuleFileName(ModuleName);
1126 
1127     // If we don't already have an ASTReader, create one now.
1128     if (!ModuleManager) {
1129       if (!hasASTContext())
1130         createASTContext();
1131 
1132       // If we're not recursively building a module, check whether we
1133       // need to prune the module cache.
1134       if (getSourceManager().getModuleBuildStack().empty() &&
1135           getHeaderSearchOpts().ModuleCachePruneInterval > 0 &&
1136           getHeaderSearchOpts().ModuleCachePruneAfter > 0) {
1137         pruneModuleCache(getHeaderSearchOpts());
1138       }
1139 
1140       std::string Sysroot = getHeaderSearchOpts().Sysroot;
1141       const PreprocessorOptions &PPOpts = getPreprocessorOpts();
1142       ModuleManager = new ASTReader(getPreprocessor(), *Context,
1143                                     Sysroot.empty() ? "" : Sysroot.c_str(),
1144                                     PPOpts.DisablePCHValidation,
1145                                     /*AllowASTWithCompilerErrors=*/false,
1146                                     getFrontendOpts().UseGlobalModuleIndex);
1147       if (hasASTConsumer()) {
1148         ModuleManager->setDeserializationListener(
1149           getASTConsumer().GetASTDeserializationListener());
1150         getASTContext().setASTMutationListener(
1151           getASTConsumer().GetASTMutationListener());
1152       }
1153       OwningPtr<ExternalASTSource> Source;
1154       Source.reset(ModuleManager);
1155       getASTContext().setExternalSource(Source);
1156       if (hasSema())
1157         ModuleManager->InitializeSema(getSema());
1158       if (hasASTConsumer())
1159         ModuleManager->StartTranslationUnit(&getASTConsumer());
1160     }
1161 
1162     // Try to load the module file.
1163     unsigned ARRFlags = ASTReader::ARR_OutOfDate | ASTReader::ARR_Missing;
1164     switch (ModuleManager->ReadAST(ModuleFileName, serialization::MK_Module,
1165                                    ImportLoc, ARRFlags)) {
1166     case ASTReader::Success:
1167       break;
1168 
1169     case ASTReader::OutOfDate: {
1170       // The module file is out-of-date. Remove it, then rebuild it.
1171       bool Existed;
1172       llvm::sys::fs::remove(ModuleFileName, Existed);
1173     }
1174     // Fall through to build the module again.
1175 
1176     case ASTReader::Missing: {
1177       // The module file is (now) missing. Build it.
1178 
1179       // If we don't have a module, we don't know how to build the module file.
1180       // Complain and return.
1181       if (!Module) {
1182         getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_found)
1183           << ModuleName
1184           << SourceRange(ImportLoc, ModuleNameLoc);
1185         ModuleBuildFailed = true;
1186         return ModuleLoadResult();
1187       }
1188 
1189       // Check whether there is a cycle in the module graph.
1190       ModuleBuildStack ModPath = getSourceManager().getModuleBuildStack();
1191       ModuleBuildStack::iterator Pos = ModPath.begin(), PosEnd = ModPath.end();
1192       for (; Pos != PosEnd; ++Pos) {
1193         if (Pos->first == ModuleName)
1194           break;
1195       }
1196 
1197       if (Pos != PosEnd) {
1198         SmallString<256> CyclePath;
1199         for (; Pos != PosEnd; ++Pos) {
1200           CyclePath += Pos->first;
1201           CyclePath += " -> ";
1202         }
1203         CyclePath += ModuleName;
1204 
1205         getDiagnostics().Report(ModuleNameLoc, diag::err_module_cycle)
1206           << ModuleName << CyclePath;
1207         return ModuleLoadResult();
1208       }
1209 
1210       // Check whether we have already attempted to build this module (but
1211       // failed).
1212       if (getPreprocessorOpts().FailedModules &&
1213           getPreprocessorOpts().FailedModules->hasAlreadyFailed(ModuleName)) {
1214         getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_built)
1215           << ModuleName
1216           << SourceRange(ImportLoc, ModuleNameLoc);
1217         ModuleBuildFailed = true;
1218         return ModuleLoadResult();
1219       }
1220 
1221       // Try to compile the module.
1222       compileModule(*this, ModuleNameLoc, Module, ModuleFileName);
1223 
1224       // Try to read the module file, now that we've compiled it.
1225       ASTReader::ASTReadResult ReadResult
1226         = ModuleManager->ReadAST(ModuleFileName,
1227                                  serialization::MK_Module, ImportLoc,
1228                                  ASTReader::ARR_Missing);
1229       if (ReadResult != ASTReader::Success) {
1230         if (ReadResult == ASTReader::Missing) {
1231           getDiagnostics().Report(ModuleNameLoc,
1232                                   Module? diag::err_module_not_built
1233                                         : diag::err_module_not_found)
1234             << ModuleName
1235             << SourceRange(ImportLoc, ModuleNameLoc);
1236         }
1237 
1238         if (getPreprocessorOpts().FailedModules)
1239           getPreprocessorOpts().FailedModules->addFailed(ModuleName);
1240         KnownModules[Path[0].first] = 0;
1241         ModuleBuildFailed = true;
1242         return ModuleLoadResult();
1243       }
1244 
1245       // Okay, we've rebuilt and now loaded the module.
1246       break;
1247     }
1248 
1249     case ASTReader::VersionMismatch:
1250     case ASTReader::ConfigurationMismatch:
1251     case ASTReader::HadErrors:
1252       ModuleLoader::HadFatalFailure = true;
1253       // FIXME: The ASTReader will already have complained, but can we showhorn
1254       // that diagnostic information into a more useful form?
1255       KnownModules[Path[0].first] = 0;
1256       return ModuleLoadResult();
1257 
1258     case ASTReader::Failure:
1259       ModuleLoader::HadFatalFailure = true;
1260       // Already complained, but note now that we failed.
1261       KnownModules[Path[0].first] = 0;
1262       ModuleBuildFailed = true;
1263       return ModuleLoadResult();
1264     }
1265 
1266     if (!Module) {
1267       // If we loaded the module directly, without finding a module map first,
1268       // we'll have loaded the module's information from the module itself.
1269       Module = PP->getHeaderSearchInfo().getModuleMap()
1270                  .findModule((Path[0].first->getName()));
1271     }
1272 
1273     // Cache the result of this top-level module lookup for later.
1274     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1275   }
1276 
1277   // If we never found the module, fail.
1278   if (!Module)
1279     return ModuleLoadResult();
1280 
1281   // Verify that the rest of the module path actually corresponds to
1282   // a submodule.
1283   if (Path.size() > 1) {
1284     for (unsigned I = 1, N = Path.size(); I != N; ++I) {
1285       StringRef Name = Path[I].first->getName();
1286       clang::Module *Sub = Module->findSubmodule(Name);
1287 
1288       if (!Sub) {
1289         // Attempt to perform typo correction to find a module name that works.
1290         SmallVector<StringRef, 2> Best;
1291         unsigned BestEditDistance = (std::numeric_limits<unsigned>::max)();
1292 
1293         for (clang::Module::submodule_iterator J = Module->submodule_begin(),
1294                                             JEnd = Module->submodule_end();
1295              J != JEnd; ++J) {
1296           unsigned ED = Name.edit_distance((*J)->Name,
1297                                            /*AllowReplacements=*/true,
1298                                            BestEditDistance);
1299           if (ED <= BestEditDistance) {
1300             if (ED < BestEditDistance) {
1301               Best.clear();
1302               BestEditDistance = ED;
1303             }
1304 
1305             Best.push_back((*J)->Name);
1306           }
1307         }
1308 
1309         // If there was a clear winner, user it.
1310         if (Best.size() == 1) {
1311           getDiagnostics().Report(Path[I].second,
1312                                   diag::err_no_submodule_suggest)
1313             << Path[I].first << Module->getFullModuleName() << Best[0]
1314             << SourceRange(Path[0].second, Path[I-1].second)
1315             << FixItHint::CreateReplacement(SourceRange(Path[I].second),
1316                                             Best[0]);
1317 
1318           Sub = Module->findSubmodule(Best[0]);
1319         }
1320       }
1321 
1322       if (!Sub) {
1323         // No submodule by this name. Complain, and don't look for further
1324         // submodules.
1325         getDiagnostics().Report(Path[I].second, diag::err_no_submodule)
1326           << Path[I].first << Module->getFullModuleName()
1327           << SourceRange(Path[0].second, Path[I-1].second);
1328         break;
1329       }
1330 
1331       Module = Sub;
1332     }
1333   }
1334 
1335   // Make the named module visible, if it's not already part of the module
1336   // we are parsing.
1337   if (ModuleName != getLangOpts().CurrentModule) {
1338     if (!Module->IsFromModuleFile) {
1339       // We have an umbrella header or directory that doesn't actually include
1340       // all of the headers within the directory it covers. Complain about
1341       // this missing submodule and recover by forgetting that we ever saw
1342       // this submodule.
1343       // FIXME: Should we detect this at module load time? It seems fairly
1344       // expensive (and rare).
1345       getDiagnostics().Report(ImportLoc, diag::warn_missing_submodule)
1346         << Module->getFullModuleName()
1347         << SourceRange(Path.front().second, Path.back().second);
1348 
1349       return ModuleLoadResult(0, true);
1350     }
1351 
1352     // Check whether this module is available.
1353     StringRef Feature;
1354     if (!Module->isAvailable(getLangOpts(), getTarget(), Feature)) {
1355       getDiagnostics().Report(ImportLoc, diag::err_module_unavailable)
1356         << Module->getFullModuleName()
1357         << Feature
1358         << SourceRange(Path.front().second, Path.back().second);
1359       LastModuleImportLoc = ImportLoc;
1360       LastModuleImportResult = ModuleLoadResult();
1361       return ModuleLoadResult();
1362     }
1363 
1364     ModuleManager->makeModuleVisible(Module, Visibility, ImportLoc,
1365                                      /*Complain=*/true);
1366   }
1367 
1368   // Check for any configuration macros that have changed.
1369   clang::Module *TopModule = Module->getTopLevelModule();
1370   for (unsigned I = 0, N = TopModule->ConfigMacros.size(); I != N; ++I) {
1371     checkConfigMacro(getPreprocessor(), TopModule->ConfigMacros[I],
1372                      Module, ImportLoc);
1373   }
1374 
1375   // If this module import was due to an inclusion directive, create an
1376   // implicit import declaration to capture it in the AST.
1377   if (IsInclusionDirective && hasASTContext()) {
1378     TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
1379     ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
1380                                                      ImportLoc, Module,
1381                                                      Path.back().second);
1382     TU->addDecl(ImportD);
1383     if (Consumer)
1384       Consumer->HandleImplicitImportDecl(ImportD);
1385   }
1386 
1387   LastModuleImportLoc = ImportLoc;
1388   LastModuleImportResult = ModuleLoadResult(Module, false);
1389   return LastModuleImportResult;
1390 }
1391 
1392 void CompilerInstance::makeModuleVisible(Module *Mod,
1393                                          Module::NameVisibilityKind Visibility,
1394                                          SourceLocation ImportLoc,
1395                                          bool Complain){
1396   ModuleManager->makeModuleVisible(Mod, Visibility, ImportLoc, Complain);
1397 }
1398 
1399