xref: /llvm-project/clang/lib/Frontend/CompilerInstance.cpp (revision cb69b57b2a8903fc9de4c33ec2988daa6d56ba40)
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/Program.h"
43 #include "llvm/Support/Signals.h"
44 #include "llvm/Support/Timer.h"
45 #include "llvm/Support/raw_ostream.h"
46 #include "llvm/Support/system_error.h"
47 #include <sys/stat.h>
48 #include <time.h>
49 
50 using namespace clang;
51 
52 CompilerInstance::CompilerInstance()
53   : Invocation(new CompilerInvocation()), ModuleManager(0),
54     BuildGlobalModuleIndex(false), ModuleBuildFailed(false) {
55 }
56 
57 CompilerInstance::~CompilerInstance() {
58   assert(OutputFiles.empty() && "Still output files in flight?");
59 }
60 
61 void CompilerInstance::setInvocation(CompilerInvocation *Value) {
62   Invocation = Value;
63 }
64 
65 bool CompilerInstance::shouldBuildGlobalModuleIndex() const {
66   return (BuildGlobalModuleIndex ||
67           (ModuleManager && ModuleManager->isGlobalIndexUnavailable() &&
68            getFrontendOpts().GenerateGlobalModuleIndex)) &&
69          !ModuleBuildFailed;
70 }
71 
72 void CompilerInstance::setDiagnostics(DiagnosticsEngine *Value) {
73   Diagnostics = Value;
74 }
75 
76 void CompilerInstance::setTarget(TargetInfo *Value) {
77   Target = Value;
78 }
79 
80 void CompilerInstance::setFileManager(FileManager *Value) {
81   FileMgr = Value;
82   if (Value)
83     VirtualFileSystem = Value->getVirtualFileSystem();
84   else
85     VirtualFileSystem.reset();
86 }
87 
88 void CompilerInstance::setSourceManager(SourceManager *Value) {
89   SourceMgr = Value;
90 }
91 
92 void CompilerInstance::setPreprocessor(Preprocessor *Value) { PP = Value; }
93 
94 void CompilerInstance::setASTContext(ASTContext *Value) { Context = Value; }
95 
96 void CompilerInstance::setSema(Sema *S) {
97   TheSema.reset(S);
98 }
99 
100 void CompilerInstance::setASTConsumer(ASTConsumer *Value) {
101   Consumer.reset(Value);
102 }
103 
104 void CompilerInstance::setCodeCompletionConsumer(CodeCompleteConsumer *Value) {
105   CompletionConsumer.reset(Value);
106 }
107 
108 IntrusiveRefCntPtr<ASTReader> CompilerInstance::getModuleManager() const {
109   return ModuleManager;
110 }
111 void CompilerInstance::setModuleManager(IntrusiveRefCntPtr<ASTReader> Reader) {
112   ModuleManager = Reader;
113 }
114 
115 // Diagnostics
116 static void SetUpDiagnosticLog(DiagnosticOptions *DiagOpts,
117                                const CodeGenOptions *CodeGenOpts,
118                                DiagnosticsEngine &Diags) {
119   std::string ErrorInfo;
120   bool OwnsStream = false;
121   raw_ostream *OS = &llvm::errs();
122   if (DiagOpts->DiagnosticLogFile != "-") {
123     // Create the output stream.
124     llvm::raw_fd_ostream *FileOS(new llvm::raw_fd_ostream(
125         DiagOpts->DiagnosticLogFile.c_str(), ErrorInfo,
126         llvm::sys::fs::F_Append | llvm::sys::fs::F_Text));
127     if (!ErrorInfo.empty()) {
128       Diags.Report(diag::warn_fe_cc_log_diagnostics_failure)
129         << DiagOpts->DiagnosticLogFile << ErrorInfo;
130     } else {
131       FileOS->SetUnbuffered();
132       FileOS->SetUseAtomicWrites(true);
133       OS = FileOS;
134       OwnsStream = true;
135     }
136   }
137 
138   // Chain in the diagnostic client which will log the diagnostics.
139   LogDiagnosticPrinter *Logger = new LogDiagnosticPrinter(*OS, DiagOpts,
140                                                           OwnsStream);
141   if (CodeGenOpts)
142     Logger->setDwarfDebugFlags(CodeGenOpts->DwarfDebugFlags);
143   Diags.setClient(new ChainedDiagnosticConsumer(Diags.takeClient(), Logger));
144 }
145 
146 static void SetupSerializedDiagnostics(DiagnosticOptions *DiagOpts,
147                                        DiagnosticsEngine &Diags,
148                                        StringRef OutputFile) {
149   std::string ErrorInfo;
150   OwningPtr<llvm::raw_fd_ostream> OS;
151   OS.reset(new llvm::raw_fd_ostream(OutputFile.str().c_str(), ErrorInfo,
152                                     llvm::sys::fs::F_None));
153 
154   if (!ErrorInfo.empty()) {
155     Diags.Report(diag::warn_fe_serialized_diag_failure)
156       << OutputFile << ErrorInfo;
157     return;
158   }
159 
160   DiagnosticConsumer *SerializedConsumer =
161     clang::serialized_diags::create(OS.take(), DiagOpts);
162 
163 
164   Diags.setClient(new ChainedDiagnosticConsumer(Diags.takeClient(),
165                                                 SerializedConsumer));
166 }
167 
168 void CompilerInstance::createDiagnostics(DiagnosticConsumer *Client,
169                                          bool ShouldOwnClient) {
170   Diagnostics = createDiagnostics(&getDiagnosticOpts(), Client,
171                                   ShouldOwnClient, &getCodeGenOpts());
172 }
173 
174 IntrusiveRefCntPtr<DiagnosticsEngine>
175 CompilerInstance::createDiagnostics(DiagnosticOptions *Opts,
176                                     DiagnosticConsumer *Client,
177                                     bool ShouldOwnClient,
178                                     const CodeGenOptions *CodeGenOpts) {
179   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
180   IntrusiveRefCntPtr<DiagnosticsEngine>
181       Diags(new DiagnosticsEngine(DiagID, Opts));
182 
183   // Create the diagnostic client for reporting errors or for
184   // implementing -verify.
185   if (Client) {
186     Diags->setClient(Client, ShouldOwnClient);
187   } else
188     Diags->setClient(new TextDiagnosticPrinter(llvm::errs(), Opts));
189 
190   // Chain in -verify checker, if requested.
191   if (Opts->VerifyDiagnostics)
192     Diags->setClient(new VerifyDiagnosticConsumer(*Diags));
193 
194   // Chain in -diagnostic-log-file dumper, if requested.
195   if (!Opts->DiagnosticLogFile.empty())
196     SetUpDiagnosticLog(Opts, CodeGenOpts, *Diags);
197 
198   if (!Opts->DiagnosticSerializationFile.empty())
199     SetupSerializedDiagnostics(Opts, *Diags,
200                                Opts->DiagnosticSerializationFile);
201 
202   // Configure our handling of diagnostics.
203   ProcessWarningOptions(*Diags, *Opts);
204 
205   return Diags;
206 }
207 
208 // File Manager
209 
210 void CompilerInstance::createFileManager() {
211   if (!hasVirtualFileSystem()) {
212     // TODO: choose the virtual file system based on the CompilerInvocation.
213     setVirtualFileSystem(vfs::getRealFileSystem());
214   }
215   FileMgr = new FileManager(getFileSystemOpts(), VirtualFileSystem);
216 }
217 
218 // Source Manager
219 
220 void CompilerInstance::createSourceManager(FileManager &FileMgr) {
221   SourceMgr = new SourceManager(getDiagnostics(), FileMgr);
222 }
223 
224 // Preprocessor
225 
226 void CompilerInstance::createPreprocessor() {
227   const PreprocessorOptions &PPOpts = getPreprocessorOpts();
228 
229   // Create a PTH manager if we are using some form of a token cache.
230   PTHManager *PTHMgr = 0;
231   if (!PPOpts.TokenCache.empty())
232     PTHMgr = PTHManager::Create(PPOpts.TokenCache, getDiagnostics());
233 
234   // Create the Preprocessor.
235   HeaderSearch *HeaderInfo = new HeaderSearch(&getHeaderSearchOpts(),
236                                               getSourceManager(),
237                                               getDiagnostics(),
238                                               getLangOpts(),
239                                               &getTarget());
240   PP = new Preprocessor(&getPreprocessorOpts(),
241                         getDiagnostics(), getLangOpts(), &getTarget(),
242                         getSourceManager(), *HeaderInfo, *this, PTHMgr,
243                         /*OwnsHeaderSearch=*/true);
244 
245   // Note that this is different then passing PTHMgr to Preprocessor's ctor.
246   // That argument is used as the IdentifierInfoLookup argument to
247   // IdentifierTable's ctor.
248   if (PTHMgr) {
249     PTHMgr->setPreprocessor(&*PP);
250     PP->setPTHManager(PTHMgr);
251   }
252 
253   if (PPOpts.DetailedRecord)
254     PP->createPreprocessingRecord();
255 
256   InitializePreprocessor(*PP, PPOpts, getHeaderSearchOpts(), getFrontendOpts());
257 
258   PP->setPreprocessedOutput(getPreprocessorOutputOpts().ShowCPP);
259 
260   // Set up the module path, including the hash for the
261   // module-creation options.
262   SmallString<256> SpecificModuleCache(
263                            getHeaderSearchOpts().ModuleCachePath);
264   if (!getHeaderSearchOpts().DisableModuleHash)
265     llvm::sys::path::append(SpecificModuleCache,
266                             getInvocation().getModuleHash());
267   PP->getHeaderSearchInfo().setModuleCachePath(SpecificModuleCache);
268 
269   // Handle generating dependencies, if requested.
270   const DependencyOutputOptions &DepOpts = getDependencyOutputOpts();
271   if (!DepOpts.OutputFile.empty())
272     TheDependencyFileGenerator.reset(
273         DependencyFileGenerator::CreateAndAttachToPreprocessor(*PP, DepOpts));
274   if (!DepOpts.DOTOutputFile.empty())
275     AttachDependencyGraphGen(*PP, DepOpts.DOTOutputFile,
276                              getHeaderSearchOpts().Sysroot);
277 
278 
279   // Handle generating header include information, if requested.
280   if (DepOpts.ShowHeaderIncludes)
281     AttachHeaderIncludeGen(*PP);
282   if (!DepOpts.HeaderIncludeOutputFile.empty()) {
283     StringRef OutputPath = DepOpts.HeaderIncludeOutputFile;
284     if (OutputPath == "-")
285       OutputPath = "";
286     AttachHeaderIncludeGen(*PP, /*ShowAllHeaders=*/true, OutputPath,
287                            /*ShowDepth=*/false);
288   }
289 
290   if (DepOpts.PrintShowIncludes) {
291     AttachHeaderIncludeGen(*PP, /*ShowAllHeaders=*/false, /*OutputPath=*/"",
292                            /*ShowDepth=*/true, /*MSStyle=*/true);
293   }
294 }
295 
296 // ASTContext
297 
298 void CompilerInstance::createASTContext() {
299   Preprocessor &PP = getPreprocessor();
300   Context = new ASTContext(getLangOpts(), PP.getSourceManager(),
301                            &getTarget(), PP.getIdentifierTable(),
302                            PP.getSelectorTable(), PP.getBuiltinInfo(),
303                            /*size_reserve=*/ 0);
304 }
305 
306 // ExternalASTSource
307 
308 void CompilerInstance::createPCHExternalASTSource(StringRef Path,
309                                                   bool DisablePCHValidation,
310                                                 bool AllowPCHWithCompilerErrors,
311                                                  void *DeserializationListener){
312   IntrusiveRefCntPtr<ExternalASTSource> Source;
313   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
314   Source = createPCHExternalASTSource(Path, getHeaderSearchOpts().Sysroot,
315                                           DisablePCHValidation,
316                                           AllowPCHWithCompilerErrors,
317                                           getPreprocessor(), getASTContext(),
318                                           DeserializationListener,
319                                           Preamble,
320                                        getFrontendOpts().UseGlobalModuleIndex);
321   ModuleManager = static_cast<ASTReader*>(Source.getPtr());
322   getASTContext().setExternalSource(Source);
323 }
324 
325 ExternalASTSource *
326 CompilerInstance::createPCHExternalASTSource(StringRef Path,
327                                              const std::string &Sysroot,
328                                              bool DisablePCHValidation,
329                                              bool AllowPCHWithCompilerErrors,
330                                              Preprocessor &PP,
331                                              ASTContext &Context,
332                                              void *DeserializationListener,
333                                              bool Preamble,
334                                              bool UseGlobalModuleIndex) {
335   OwningPtr<ASTReader> Reader;
336   Reader.reset(new ASTReader(PP, Context,
337                              Sysroot.empty() ? "" : Sysroot.c_str(),
338                              DisablePCHValidation,
339                              AllowPCHWithCompilerErrors,
340                              /*AllowConfigurationMismatch*/false,
341                              /*ValidateSystemInputs*/false,
342                              UseGlobalModuleIndex));
343 
344   Reader->setDeserializationListener(
345             static_cast<ASTDeserializationListener *>(DeserializationListener));
346   switch (Reader->ReadAST(Path,
347                           Preamble ? serialization::MK_Preamble
348                                    : serialization::MK_PCH,
349                           SourceLocation(),
350                           ASTReader::ARR_None)) {
351   case ASTReader::Success:
352     // Set the predefines buffer as suggested by the PCH reader. Typically, the
353     // predefines buffer will be empty.
354     PP.setPredefines(Reader->getSuggestedPredefines());
355     return Reader.take();
356 
357   case ASTReader::Failure:
358     // Unrecoverable failure: don't even try to process the input file.
359     break;
360 
361   case ASTReader::Missing:
362   case ASTReader::OutOfDate:
363   case ASTReader::VersionMismatch:
364   case ASTReader::ConfigurationMismatch:
365   case ASTReader::HadErrors:
366     // No suitable PCH file could be found. Return an error.
367     break;
368   }
369 
370   return 0;
371 }
372 
373 // Code Completion
374 
375 static bool EnableCodeCompletion(Preprocessor &PP,
376                                  const std::string &Filename,
377                                  unsigned Line,
378                                  unsigned Column) {
379   // Tell the source manager to chop off the given file at a specific
380   // line and column.
381   const FileEntry *Entry = PP.getFileManager().getFile(Filename);
382   if (!Entry) {
383     PP.getDiagnostics().Report(diag::err_fe_invalid_code_complete_file)
384       << Filename;
385     return true;
386   }
387 
388   // Truncate the named file at the given line/column.
389   PP.SetCodeCompletionPoint(Entry, Line, Column);
390   return false;
391 }
392 
393 void CompilerInstance::createCodeCompletionConsumer() {
394   const ParsedSourceLocation &Loc = getFrontendOpts().CodeCompletionAt;
395   if (!CompletionConsumer) {
396     setCodeCompletionConsumer(
397       createCodeCompletionConsumer(getPreprocessor(),
398                                    Loc.FileName, Loc.Line, Loc.Column,
399                                    getFrontendOpts().CodeCompleteOpts,
400                                    llvm::outs()));
401     if (!CompletionConsumer)
402       return;
403   } else if (EnableCodeCompletion(getPreprocessor(), Loc.FileName,
404                                   Loc.Line, Loc.Column)) {
405     setCodeCompletionConsumer(0);
406     return;
407   }
408 
409   if (CompletionConsumer->isOutputBinary() &&
410       llvm::sys::ChangeStdoutToBinary()) {
411     getPreprocessor().getDiagnostics().Report(diag::err_fe_stdout_binary);
412     setCodeCompletionConsumer(0);
413   }
414 }
415 
416 void CompilerInstance::createFrontendTimer() {
417   FrontendTimer.reset(new llvm::Timer("Clang front-end timer"));
418 }
419 
420 CodeCompleteConsumer *
421 CompilerInstance::createCodeCompletionConsumer(Preprocessor &PP,
422                                                const std::string &Filename,
423                                                unsigned Line,
424                                                unsigned Column,
425                                                const CodeCompleteOptions &Opts,
426                                                raw_ostream &OS) {
427   if (EnableCodeCompletion(PP, Filename, Line, Column))
428     return 0;
429 
430   // Set up the creation routine for code-completion.
431   return new PrintingCodeCompleteConsumer(Opts, OS);
432 }
433 
434 void CompilerInstance::createSema(TranslationUnitKind TUKind,
435                                   CodeCompleteConsumer *CompletionConsumer) {
436   TheSema.reset(new Sema(getPreprocessor(), getASTContext(), getASTConsumer(),
437                          TUKind, CompletionConsumer));
438 }
439 
440 // Output Files
441 
442 void CompilerInstance::addOutputFile(const OutputFile &OutFile) {
443   assert(OutFile.OS && "Attempt to add empty stream to output list!");
444   OutputFiles.push_back(OutFile);
445 }
446 
447 void CompilerInstance::clearOutputFiles(bool EraseFiles) {
448   for (std::list<OutputFile>::iterator
449          it = OutputFiles.begin(), ie = OutputFiles.end(); it != ie; ++it) {
450     delete it->OS;
451     if (!it->TempFilename.empty()) {
452       if (EraseFiles) {
453         llvm::sys::fs::remove(it->TempFilename);
454       } else {
455         SmallString<128> NewOutFile(it->Filename);
456 
457         // If '-working-directory' was passed, the output filename should be
458         // relative to that.
459         FileMgr->FixupRelativePath(NewOutFile);
460         if (llvm::error_code ec = llvm::sys::fs::rename(it->TempFilename,
461                                                         NewOutFile.str())) {
462           getDiagnostics().Report(diag::err_unable_to_rename_temp)
463             << it->TempFilename << it->Filename << ec.message();
464 
465           llvm::sys::fs::remove(it->TempFilename);
466         }
467       }
468     } else if (!it->Filename.empty() && EraseFiles)
469       llvm::sys::fs::remove(it->Filename);
470 
471   }
472   OutputFiles.clear();
473 }
474 
475 llvm::raw_fd_ostream *
476 CompilerInstance::createDefaultOutputFile(bool Binary,
477                                           StringRef InFile,
478                                           StringRef Extension) {
479   return createOutputFile(getFrontendOpts().OutputFile, Binary,
480                           /*RemoveFileOnSignal=*/true, InFile, Extension,
481                           /*UseTemporary=*/true);
482 }
483 
484 llvm::raw_fd_ostream *
485 CompilerInstance::createOutputFile(StringRef OutputPath,
486                                    bool Binary, bool RemoveFileOnSignal,
487                                    StringRef InFile,
488                                    StringRef Extension,
489                                    bool UseTemporary,
490                                    bool CreateMissingDirectories) {
491   std::string Error, OutputPathName, TempPathName;
492   llvm::raw_fd_ostream *OS = createOutputFile(OutputPath, Error, Binary,
493                                               RemoveFileOnSignal,
494                                               InFile, Extension,
495                                               UseTemporary,
496                                               CreateMissingDirectories,
497                                               &OutputPathName,
498                                               &TempPathName);
499   if (!OS) {
500     getDiagnostics().Report(diag::err_fe_unable_to_open_output)
501       << OutputPath << Error;
502     return 0;
503   }
504 
505   // Add the output file -- but don't try to remove "-", since this means we are
506   // using stdin.
507   addOutputFile(OutputFile((OutputPathName != "-") ? OutputPathName : "",
508                 TempPathName, OS));
509 
510   return OS;
511 }
512 
513 llvm::raw_fd_ostream *
514 CompilerInstance::createOutputFile(StringRef OutputPath,
515                                    std::string &Error,
516                                    bool Binary,
517                                    bool RemoveFileOnSignal,
518                                    StringRef InFile,
519                                    StringRef Extension,
520                                    bool UseTemporary,
521                                    bool CreateMissingDirectories,
522                                    std::string *ResultPathName,
523                                    std::string *TempPathName) {
524   assert((!CreateMissingDirectories || UseTemporary) &&
525          "CreateMissingDirectories is only allowed when using temporary files");
526 
527   std::string OutFile, TempFile;
528   if (!OutputPath.empty()) {
529     OutFile = OutputPath;
530   } else if (InFile == "-") {
531     OutFile = "-";
532   } else if (!Extension.empty()) {
533     SmallString<128> Path(InFile);
534     llvm::sys::path::replace_extension(Path, Extension);
535     OutFile = Path.str();
536   } else {
537     OutFile = "-";
538   }
539 
540   OwningPtr<llvm::raw_fd_ostream> OS;
541   std::string OSFile;
542 
543   if (UseTemporary) {
544     if (OutFile == "-")
545       UseTemporary = false;
546     else {
547       llvm::sys::fs::file_status Status;
548       llvm::sys::fs::status(OutputPath, Status);
549       if (llvm::sys::fs::exists(Status)) {
550         // Fail early if we can't write to the final destination.
551         if (!llvm::sys::fs::can_write(OutputPath))
552           return 0;
553 
554         // Don't use a temporary if the output is a special file. This handles
555         // things like '-o /dev/null'
556         if (!llvm::sys::fs::is_regular_file(Status))
557           UseTemporary = false;
558       }
559     }
560   }
561 
562   if (UseTemporary) {
563     // Create a temporary file.
564     SmallString<128> TempPath;
565     TempPath = OutFile;
566     TempPath += "-%%%%%%%%";
567     int fd;
568     llvm::error_code EC =
569         llvm::sys::fs::createUniqueFile(TempPath.str(), fd, TempPath);
570 
571     if (CreateMissingDirectories &&
572         EC == llvm::errc::no_such_file_or_directory) {
573       StringRef Parent = llvm::sys::path::parent_path(OutputPath);
574       EC = llvm::sys::fs::create_directories(Parent);
575       if (!EC) {
576         EC = llvm::sys::fs::createUniqueFile(TempPath.str(), fd, TempPath);
577       }
578     }
579 
580     if (!EC) {
581       OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
582       OSFile = TempFile = TempPath.str();
583     }
584     // If we failed to create the temporary, fallback to writing to the file
585     // directly. This handles the corner case where we cannot write to the
586     // directory, but can write to the file.
587   }
588 
589   if (!OS) {
590     OSFile = OutFile;
591     OS.reset(new llvm::raw_fd_ostream(
592         OSFile.c_str(), Error,
593         (Binary ? llvm::sys::fs::F_None : llvm::sys::fs::F_Text)));
594     if (!Error.empty())
595       return 0;
596   }
597 
598   // Make sure the out stream file gets removed if we crash.
599   if (RemoveFileOnSignal)
600     llvm::sys::RemoveFileOnSignal(OSFile);
601 
602   if (ResultPathName)
603     *ResultPathName = OutFile;
604   if (TempPathName)
605     *TempPathName = TempFile;
606 
607   return OS.take();
608 }
609 
610 // Initialization Utilities
611 
612 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input){
613   return InitializeSourceManager(Input, getDiagnostics(),
614                                  getFileManager(), getSourceManager(),
615                                  getFrontendOpts());
616 }
617 
618 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input,
619                                                DiagnosticsEngine &Diags,
620                                                FileManager &FileMgr,
621                                                SourceManager &SourceMgr,
622                                                const FrontendOptions &Opts) {
623   SrcMgr::CharacteristicKind
624     Kind = Input.isSystem() ? SrcMgr::C_System : SrcMgr::C_User;
625 
626   if (Input.isBuffer()) {
627     SourceMgr.createMainFileIDForMemBuffer(Input.getBuffer(), Kind);
628     assert(!SourceMgr.getMainFileID().isInvalid() &&
629            "Couldn't establish MainFileID!");
630     return true;
631   }
632 
633   StringRef InputFile = Input.getFile();
634 
635   // Figure out where to get and map in the main file.
636   if (InputFile != "-") {
637     const FileEntry *File = FileMgr.getFile(InputFile, /*OpenFile=*/true);
638     if (!File) {
639       Diags.Report(diag::err_fe_error_reading) << InputFile;
640       return false;
641     }
642 
643     // The natural SourceManager infrastructure can't currently handle named
644     // pipes, but we would at least like to accept them for the main
645     // file. Detect them here, read them with the volatile flag so FileMgr will
646     // pick up the correct size, and simply override their contents as we do for
647     // STDIN.
648     if (File->isNamedPipe()) {
649       std::string ErrorStr;
650       if (llvm::MemoryBuffer *MB =
651               FileMgr.getBufferForFile(File, &ErrorStr, /*isVolatile=*/true)) {
652         // Create a new virtual file that will have the correct size.
653         File = FileMgr.getVirtualFile(InputFile, MB->getBufferSize(), 0);
654         SourceMgr.overrideFileContents(File, MB);
655       } else {
656         Diags.Report(diag::err_cannot_open_file) << InputFile << ErrorStr;
657         return false;
658       }
659     }
660 
661     SourceMgr.createMainFileID(File, Kind);
662   } else {
663     OwningPtr<llvm::MemoryBuffer> SB;
664     if (llvm::error_code ec = llvm::MemoryBuffer::getSTDIN(SB)) {
665       Diags.Report(diag::err_fe_error_reading_stdin) << ec.message();
666       return false;
667     }
668     const FileEntry *File = FileMgr.getVirtualFile(SB->getBufferIdentifier(),
669                                                    SB->getBufferSize(), 0);
670     SourceMgr.createMainFileID(File, Kind);
671     SourceMgr.overrideFileContents(File, SB.take());
672   }
673 
674   assert(!SourceMgr.getMainFileID().isInvalid() &&
675          "Couldn't establish MainFileID!");
676   return true;
677 }
678 
679 // High-Level Operations
680 
681 bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
682   assert(hasDiagnostics() && "Diagnostics engine is not initialized!");
683   assert(!getFrontendOpts().ShowHelp && "Client must handle '-help'!");
684   assert(!getFrontendOpts().ShowVersion && "Client must handle '-version'!");
685 
686   // FIXME: Take this as an argument, once all the APIs we used have moved to
687   // taking it as an input instead of hard-coding llvm::errs.
688   raw_ostream &OS = llvm::errs();
689 
690   // Create the target instance.
691   setTarget(TargetInfo::CreateTargetInfo(getDiagnostics(), &getTargetOpts()));
692   if (!hasTarget())
693     return false;
694 
695   // Inform the target of the language options.
696   //
697   // FIXME: We shouldn't need to do this, the target should be immutable once
698   // created. This complexity should be lifted elsewhere.
699   getTarget().setForcedLangOptions(getLangOpts());
700 
701   // rewriter project will change target built-in bool type from its default.
702   if (getFrontendOpts().ProgramAction == frontend::RewriteObjC)
703     getTarget().noSignedCharForObjCBool();
704 
705   // Validate/process some options.
706   if (getHeaderSearchOpts().Verbose)
707     OS << "clang -cc1 version " CLANG_VERSION_STRING
708        << " based upon " << PACKAGE_STRING
709        << " default target " << llvm::sys::getDefaultTargetTriple() << "\n";
710 
711   if (getFrontendOpts().ShowTimers)
712     createFrontendTimer();
713 
714   if (getFrontendOpts().ShowStats)
715     llvm::EnableStatistics();
716 
717   for (unsigned i = 0, e = getFrontendOpts().Inputs.size(); i != e; ++i) {
718     // Reset the ID tables if we are reusing the SourceManager.
719     if (hasSourceManager())
720       getSourceManager().clearIDTables();
721 
722     if (Act.BeginSourceFile(*this, getFrontendOpts().Inputs[i])) {
723       Act.Execute();
724       Act.EndSourceFile();
725     }
726   }
727 
728   // Notify the diagnostic client that all files were processed.
729   getDiagnostics().getClient()->finish();
730 
731   if (getDiagnosticOpts().ShowCarets) {
732     // We can have multiple diagnostics sharing one diagnostic client.
733     // Get the total number of warnings/errors from the client.
734     unsigned NumWarnings = getDiagnostics().getClient()->getNumWarnings();
735     unsigned NumErrors = getDiagnostics().getClient()->getNumErrors();
736 
737     if (NumWarnings)
738       OS << NumWarnings << " warning" << (NumWarnings == 1 ? "" : "s");
739     if (NumWarnings && NumErrors)
740       OS << " and ";
741     if (NumErrors)
742       OS << NumErrors << " error" << (NumErrors == 1 ? "" : "s");
743     if (NumWarnings || NumErrors)
744       OS << " generated.\n";
745   }
746 
747   if (getFrontendOpts().ShowStats && hasFileManager()) {
748     getFileManager().PrintStats();
749     OS << "\n";
750   }
751 
752   return !getDiagnostics().getClient()->getNumErrors();
753 }
754 
755 /// \brief Determine the appropriate source input kind based on language
756 /// options.
757 static InputKind getSourceInputKindFromOptions(const LangOptions &LangOpts) {
758   if (LangOpts.OpenCL)
759     return IK_OpenCL;
760   if (LangOpts.CUDA)
761     return IK_CUDA;
762   if (LangOpts.ObjC1)
763     return LangOpts.CPlusPlus? IK_ObjCXX : IK_ObjC;
764   return LangOpts.CPlusPlus? IK_CXX : IK_C;
765 }
766 
767 /// \brief Compile a module file for the given module, using the options
768 /// provided by the importing compiler instance.
769 static void compileModule(CompilerInstance &ImportingInstance,
770                           SourceLocation ImportLoc,
771                           Module *Module,
772                           StringRef ModuleFileName) {
773   // FIXME: have LockFileManager return an error_code so that we can
774   // avoid the mkdir when the directory already exists.
775   StringRef Dir = llvm::sys::path::parent_path(ModuleFileName);
776   llvm::sys::fs::create_directories(Dir);
777 
778   llvm::LockFileManager Locked(ModuleFileName);
779   switch (Locked) {
780   case llvm::LockFileManager::LFS_Error:
781     return;
782 
783   case llvm::LockFileManager::LFS_Owned:
784     // We're responsible for building the module ourselves. Do so below.
785     break;
786 
787   case llvm::LockFileManager::LFS_Shared:
788     // Someone else is responsible for building the module. Wait for them to
789     // finish.
790     Locked.waitForUnlock();
791     return;
792   }
793 
794   ModuleMap &ModMap
795     = ImportingInstance.getPreprocessor().getHeaderSearchInfo().getModuleMap();
796 
797   // Construct a compiler invocation for creating this module.
798   IntrusiveRefCntPtr<CompilerInvocation> Invocation
799     (new CompilerInvocation(ImportingInstance.getInvocation()));
800 
801   PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
802 
803   // For any options that aren't intended to affect how a module is built,
804   // reset them to their default values.
805   Invocation->getLangOpts()->resetNonModularOptions();
806   PPOpts.resetNonModularOptions();
807 
808   // Remove any macro definitions that are explicitly ignored by the module.
809   // They aren't supposed to affect how the module is built anyway.
810   const HeaderSearchOptions &HSOpts = Invocation->getHeaderSearchOpts();
811   PPOpts.Macros.erase(
812       std::remove_if(PPOpts.Macros.begin(), PPOpts.Macros.end(),
813                      [&HSOpts](const std::pair<std::string, bool> &def) {
814         StringRef MacroDef = def.first;
815         return HSOpts.ModulesIgnoreMacros.count(MacroDef.split('=').first) > 0;
816       }),
817       PPOpts.Macros.end());
818 
819   // Note the name of the module we're building.
820   Invocation->getLangOpts()->CurrentModule = Module->getTopLevelModuleName();
821 
822   // Make sure that the failed-module structure has been allocated in
823   // the importing instance, and propagate the pointer to the newly-created
824   // instance.
825   PreprocessorOptions &ImportingPPOpts
826     = ImportingInstance.getInvocation().getPreprocessorOpts();
827   if (!ImportingPPOpts.FailedModules)
828     ImportingPPOpts.FailedModules = new PreprocessorOptions::FailedModulesSet;
829   PPOpts.FailedModules = ImportingPPOpts.FailedModules;
830 
831   // If there is a module map file, build the module using the module map.
832   // Set up the inputs/outputs so that we build the module from its umbrella
833   // header.
834   FrontendOptions &FrontendOpts = Invocation->getFrontendOpts();
835   FrontendOpts.OutputFile = ModuleFileName.str();
836   FrontendOpts.DisableFree = false;
837   FrontendOpts.GenerateGlobalModuleIndex = false;
838   FrontendOpts.Inputs.clear();
839   InputKind IK = getSourceInputKindFromOptions(*Invocation->getLangOpts());
840 
841   // Don't free the remapped file buffers; they are owned by our caller.
842   PPOpts.RetainRemappedFileBuffers = true;
843 
844   Invocation->getDiagnosticOpts().VerifyDiagnostics = 0;
845   assert(ImportingInstance.getInvocation().getModuleHash() ==
846          Invocation->getModuleHash() && "Module hash mismatch!");
847 
848   // Construct a compiler instance that will be used to actually create the
849   // module.
850   CompilerInstance Instance;
851   Instance.setInvocation(&*Invocation);
852 
853   Instance.createDiagnostics(new ForwardingDiagnosticConsumer(
854                                    ImportingInstance.getDiagnosticClient()),
855                              /*ShouldOwnClient=*/true);
856 
857   Instance.setVirtualFileSystem(&ImportingInstance.getVirtualFileSystem());
858 
859   // Note that this module is part of the module build stack, so that we
860   // can detect cycles in the module graph.
861   Instance.setFileManager(&ImportingInstance.getFileManager());
862   Instance.createSourceManager(Instance.getFileManager());
863   SourceManager &SourceMgr = Instance.getSourceManager();
864   SourceMgr.setModuleBuildStack(
865     ImportingInstance.getSourceManager().getModuleBuildStack());
866   SourceMgr.pushModuleBuildStack(Module->getTopLevelModuleName(),
867     FullSourceLoc(ImportLoc, ImportingInstance.getSourceManager()));
868 
869   // Get or create the module map that we'll use to build this module.
870   std::string InferredModuleMapContent;
871   if (const FileEntry *ModuleMapFile =
872           ModMap.getContainingModuleMapFile(Module)) {
873     // Use the module map where this module resides.
874     FrontendOpts.Inputs.push_back(
875         FrontendInputFile(ModuleMapFile->getName(), IK));
876   } else {
877     llvm::raw_string_ostream OS(InferredModuleMapContent);
878     Module->print(OS);
879     OS.flush();
880     FrontendOpts.Inputs.push_back(
881         FrontendInputFile("__inferred_module.map", IK));
882 
883     const llvm::MemoryBuffer *ModuleMapBuffer =
884         llvm::MemoryBuffer::getMemBuffer(InferredModuleMapContent);
885     ModuleMapFile = Instance.getFileManager().getVirtualFile(
886         "__inferred_module.map", InferredModuleMapContent.size(), 0);
887     SourceMgr.overrideFileContents(ModuleMapFile, ModuleMapBuffer);
888   }
889 
890   // Construct a module-generating action.
891   GenerateModuleAction CreateModuleAction(Module->IsSystem);
892 
893   // Execute the action to actually build the module in-place. Use a separate
894   // thread so that we get a stack large enough.
895   const unsigned ThreadStackSize = 8 << 20;
896   llvm::CrashRecoveryContext CRC;
897   CRC.RunSafelyOnThread([&]() { Instance.ExecuteAction(CreateModuleAction); },
898                         ThreadStackSize);
899 
900   // Delete the temporary module map file.
901   // FIXME: Even though we're executing under crash protection, it would still
902   // be nice to do this with RemoveFileOnSignal when we can. However, that
903   // doesn't make sense for all clients, so clean this up manually.
904   Instance.clearOutputFiles(/*EraseFiles=*/true);
905 
906   // We've rebuilt a module. If we're allowed to generate or update the global
907   // module index, record that fact in the importing compiler instance.
908   if (ImportingInstance.getFrontendOpts().GenerateGlobalModuleIndex) {
909     ImportingInstance.setBuildGlobalModuleIndex(true);
910   }
911 }
912 
913 /// \brief Diagnose differences between the current definition of the given
914 /// configuration macro and the definition provided on the command line.
915 static void checkConfigMacro(Preprocessor &PP, StringRef ConfigMacro,
916                              Module *Mod, SourceLocation ImportLoc) {
917   IdentifierInfo *Id = PP.getIdentifierInfo(ConfigMacro);
918   SourceManager &SourceMgr = PP.getSourceManager();
919 
920   // If this identifier has never had a macro definition, then it could
921   // not have changed.
922   if (!Id->hadMacroDefinition())
923     return;
924 
925   // If this identifier does not currently have a macro definition,
926   // check whether it had one on the command line.
927   if (!Id->hasMacroDefinition()) {
928     MacroDirective::DefInfo LatestDef =
929         PP.getMacroDirectiveHistory(Id)->getDefinition();
930     for (MacroDirective::DefInfo Def = LatestDef; Def;
931            Def = Def.getPreviousDefinition()) {
932       FileID FID = SourceMgr.getFileID(Def.getLocation());
933       if (FID.isInvalid())
934         continue;
935 
936       // We only care about the predefines buffer.
937       if (FID != PP.getPredefinesFileID())
938         continue;
939 
940       // This macro was defined on the command line, then #undef'd later.
941       // Complain.
942       PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
943         << true << ConfigMacro << Mod->getFullModuleName();
944       if (LatestDef.isUndefined())
945         PP.Diag(LatestDef.getUndefLocation(), diag::note_module_def_undef_here)
946           << true;
947       return;
948     }
949 
950     // Okay: no definition in the predefines buffer.
951     return;
952   }
953 
954   // This identifier has a macro definition. Check whether we had a definition
955   // on the command line.
956   MacroDirective::DefInfo LatestDef =
957       PP.getMacroDirectiveHistory(Id)->getDefinition();
958   MacroDirective::DefInfo PredefinedDef;
959   for (MacroDirective::DefInfo Def = LatestDef; Def;
960          Def = Def.getPreviousDefinition()) {
961     FileID FID = SourceMgr.getFileID(Def.getLocation());
962     if (FID.isInvalid())
963       continue;
964 
965     // We only care about the predefines buffer.
966     if (FID != PP.getPredefinesFileID())
967       continue;
968 
969     PredefinedDef = Def;
970     break;
971   }
972 
973   // If there was no definition for this macro in the predefines buffer,
974   // complain.
975   if (!PredefinedDef ||
976       (!PredefinedDef.getLocation().isValid() &&
977        PredefinedDef.getUndefLocation().isValid())) {
978     PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
979       << false << ConfigMacro << Mod->getFullModuleName();
980     PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
981       << false;
982     return;
983   }
984 
985   // If the current macro definition is the same as the predefined macro
986   // definition, it's okay.
987   if (LatestDef.getMacroInfo() == PredefinedDef.getMacroInfo() ||
988       LatestDef.getMacroInfo()->isIdenticalTo(*PredefinedDef.getMacroInfo(),PP,
989                                               /*Syntactically=*/true))
990     return;
991 
992   // The macro definitions differ.
993   PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
994     << false << ConfigMacro << Mod->getFullModuleName();
995   PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
996     << false;
997 }
998 
999 /// \brief Write a new timestamp file with the given path.
1000 static void writeTimestampFile(StringRef TimestampFile) {
1001   std::string ErrorInfo;
1002   llvm::raw_fd_ostream Out(TimestampFile.str().c_str(), ErrorInfo,
1003                            llvm::sys::fs::F_None);
1004 }
1005 
1006 /// \brief Prune the module cache of modules that haven't been accessed in
1007 /// a long time.
1008 static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
1009   struct stat StatBuf;
1010   llvm::SmallString<128> TimestampFile;
1011   TimestampFile = HSOpts.ModuleCachePath;
1012   llvm::sys::path::append(TimestampFile, "modules.timestamp");
1013 
1014   // Try to stat() the timestamp file.
1015   if (::stat(TimestampFile.c_str(), &StatBuf)) {
1016     // If the timestamp file wasn't there, create one now.
1017     if (errno == ENOENT) {
1018       writeTimestampFile(TimestampFile);
1019     }
1020     return;
1021   }
1022 
1023   // Check whether the time stamp is older than our pruning interval.
1024   // If not, do nothing.
1025   time_t TimeStampModTime = StatBuf.st_mtime;
1026   time_t CurrentTime = time(0);
1027   if (CurrentTime - TimeStampModTime <= time_t(HSOpts.ModuleCachePruneInterval))
1028     return;
1029 
1030   // Write a new timestamp file so that nobody else attempts to prune.
1031   // There is a benign race condition here, if two Clang instances happen to
1032   // notice at the same time that the timestamp is out-of-date.
1033   writeTimestampFile(TimestampFile);
1034 
1035   // Walk the entire module cache, looking for unused module files and module
1036   // indices.
1037   llvm::error_code EC;
1038   SmallString<128> ModuleCachePathNative;
1039   llvm::sys::path::native(HSOpts.ModuleCachePath, ModuleCachePathNative);
1040   for (llvm::sys::fs::directory_iterator
1041          Dir(ModuleCachePathNative.str(), EC), DirEnd;
1042        Dir != DirEnd && !EC; Dir.increment(EC)) {
1043     // If we don't have a directory, there's nothing to look into.
1044     if (!llvm::sys::fs::is_directory(Dir->path()))
1045       continue;
1046 
1047     // Walk all of the files within this directory.
1048     for (llvm::sys::fs::directory_iterator File(Dir->path(), EC), FileEnd;
1049          File != FileEnd && !EC; File.increment(EC)) {
1050       // We only care about module and global module index files.
1051       StringRef Extension = llvm::sys::path::extension(File->path());
1052       if (Extension != ".pcm" && Extension != ".timestamp" &&
1053           llvm::sys::path::filename(File->path()) != "modules.idx")
1054         continue;
1055 
1056       // Look at this file. If we can't stat it, there's nothing interesting
1057       // there.
1058       if (::stat(File->path().c_str(), &StatBuf))
1059         continue;
1060 
1061       // If the file has been used recently enough, leave it there.
1062       time_t FileAccessTime = StatBuf.st_atime;
1063       if (CurrentTime - FileAccessTime <=
1064               time_t(HSOpts.ModuleCachePruneAfter)) {
1065         continue;
1066       }
1067 
1068       // Remove the file.
1069       llvm::sys::fs::remove(File->path());
1070 
1071       // Remove the timestamp file.
1072       std::string TimpestampFilename = File->path() + ".timestamp";
1073       llvm::sys::fs::remove(TimpestampFilename);
1074     }
1075 
1076     // If we removed all of the files in the directory, remove the directory
1077     // itself.
1078     if (llvm::sys::fs::directory_iterator(Dir->path(), EC) ==
1079             llvm::sys::fs::directory_iterator() && !EC)
1080       llvm::sys::fs::remove(Dir->path());
1081   }
1082 }
1083 
1084 ModuleLoadResult
1085 CompilerInstance::loadModule(SourceLocation ImportLoc,
1086                              ModuleIdPath Path,
1087                              Module::NameVisibilityKind Visibility,
1088                              bool IsInclusionDirective) {
1089   // Determine what file we're searching from.
1090   StringRef ModuleName = Path[0].first->getName();
1091   SourceLocation ModuleNameLoc = Path[0].second;
1092 
1093   // If we've already handled this import, just return the cached result.
1094   // This one-element cache is important to eliminate redundant diagnostics
1095   // when both the preprocessor and parser see the same import declaration.
1096   if (!ImportLoc.isInvalid() && LastModuleImportLoc == ImportLoc) {
1097     // Make the named module visible.
1098     if (LastModuleImportResult && ModuleName != getLangOpts().CurrentModule)
1099       ModuleManager->makeModuleVisible(LastModuleImportResult, Visibility,
1100                                        ImportLoc, /*Complain=*/false);
1101     return LastModuleImportResult;
1102   }
1103 
1104   clang::Module *Module = 0;
1105 
1106   // If we don't already have information on this module, load the module now.
1107   llvm::DenseMap<const IdentifierInfo *, clang::Module *>::iterator Known
1108     = KnownModules.find(Path[0].first);
1109   if (Known != KnownModules.end()) {
1110     // Retrieve the cached top-level module.
1111     Module = Known->second;
1112   } else if (ModuleName == getLangOpts().CurrentModule) {
1113     // This is the module we're building.
1114     Module = PP->getHeaderSearchInfo().getModuleMap().findModule(ModuleName);
1115     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1116   } else {
1117     // Search for a module with the given name.
1118     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
1119     if (!Module) {
1120       getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_found)
1121       << ModuleName
1122       << SourceRange(ImportLoc, ModuleNameLoc);
1123       ModuleBuildFailed = true;
1124       return ModuleLoadResult();
1125     }
1126 
1127     std::string ModuleFileName = PP->getHeaderSearchInfo().getModuleFileName(Module);
1128 
1129     // If we don't already have an ASTReader, create one now.
1130     if (!ModuleManager) {
1131       if (!hasASTContext())
1132         createASTContext();
1133 
1134       // If we're not recursively building a module, check whether we
1135       // need to prune the module cache.
1136       if (getSourceManager().getModuleBuildStack().empty() &&
1137           getHeaderSearchOpts().ModuleCachePruneInterval > 0 &&
1138           getHeaderSearchOpts().ModuleCachePruneAfter > 0) {
1139         pruneModuleCache(getHeaderSearchOpts());
1140       }
1141 
1142       std::string Sysroot = getHeaderSearchOpts().Sysroot;
1143       const PreprocessorOptions &PPOpts = getPreprocessorOpts();
1144       ModuleManager = new ASTReader(getPreprocessor(), *Context,
1145                                     Sysroot.empty() ? "" : Sysroot.c_str(),
1146                                     PPOpts.DisablePCHValidation,
1147                                     /*AllowASTWithCompilerErrors=*/false,
1148                                     /*AllowConfigurationMismatch=*/false,
1149                                     /*ValidateSystemInputs=*/false,
1150                                     getFrontendOpts().UseGlobalModuleIndex);
1151       if (hasASTConsumer()) {
1152         ModuleManager->setDeserializationListener(
1153           getASTConsumer().GetASTDeserializationListener());
1154         getASTContext().setASTMutationListener(
1155           getASTConsumer().GetASTMutationListener());
1156       }
1157       getASTContext().setExternalSource(ModuleManager);
1158       if (hasSema())
1159         ModuleManager->InitializeSema(getSema());
1160       if (hasASTConsumer())
1161         ModuleManager->StartTranslationUnit(&getASTConsumer());
1162     }
1163 
1164     if (TheDependencyFileGenerator)
1165       TheDependencyFileGenerator->AttachToASTReader(*ModuleManager);
1166 
1167     // Try to load the module file.
1168     unsigned ARRFlags = ASTReader::ARR_OutOfDate | ASTReader::ARR_Missing;
1169     switch (ModuleManager->ReadAST(ModuleFileName, serialization::MK_Module,
1170                                    ImportLoc, ARRFlags)) {
1171     case ASTReader::Success:
1172       break;
1173 
1174     case ASTReader::OutOfDate:
1175     case ASTReader::Missing: {
1176       // The module file is missing or out-of-date. Build it.
1177       assert(Module && "missing module file");
1178       // Check whether there is a cycle in the module graph.
1179       ModuleBuildStack ModPath = getSourceManager().getModuleBuildStack();
1180       ModuleBuildStack::iterator Pos = ModPath.begin(), PosEnd = ModPath.end();
1181       for (; Pos != PosEnd; ++Pos) {
1182         if (Pos->first == ModuleName)
1183           break;
1184       }
1185 
1186       if (Pos != PosEnd) {
1187         SmallString<256> CyclePath;
1188         for (; Pos != PosEnd; ++Pos) {
1189           CyclePath += Pos->first;
1190           CyclePath += " -> ";
1191         }
1192         CyclePath += ModuleName;
1193 
1194         getDiagnostics().Report(ModuleNameLoc, diag::err_module_cycle)
1195           << ModuleName << CyclePath;
1196         return ModuleLoadResult();
1197       }
1198 
1199       // Check whether we have already attempted to build this module (but
1200       // failed).
1201       if (getPreprocessorOpts().FailedModules &&
1202           getPreprocessorOpts().FailedModules->hasAlreadyFailed(ModuleName)) {
1203         getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_built)
1204           << ModuleName
1205           << SourceRange(ImportLoc, ModuleNameLoc);
1206         ModuleBuildFailed = true;
1207         return ModuleLoadResult();
1208       }
1209 
1210       // Try to compile the module.
1211       compileModule(*this, ModuleNameLoc, Module, ModuleFileName);
1212 
1213       // Try to read the module file, now that we've compiled it.
1214       ASTReader::ASTReadResult ReadResult
1215         = ModuleManager->ReadAST(ModuleFileName,
1216                                  serialization::MK_Module, ImportLoc,
1217                                  ASTReader::ARR_Missing);
1218       if (ReadResult != ASTReader::Success) {
1219         if (ReadResult == ASTReader::Missing) {
1220           getDiagnostics().Report(ModuleNameLoc,
1221                                   Module? diag::err_module_not_built
1222                                         : diag::err_module_not_found)
1223             << ModuleName
1224             << SourceRange(ImportLoc, ModuleNameLoc);
1225         }
1226 
1227         if (getPreprocessorOpts().FailedModules)
1228           getPreprocessorOpts().FailedModules->addFailed(ModuleName);
1229         KnownModules[Path[0].first] = 0;
1230         ModuleBuildFailed = true;
1231         return ModuleLoadResult();
1232       }
1233 
1234       // Okay, we've rebuilt and now loaded the module.
1235       break;
1236     }
1237 
1238     case ASTReader::VersionMismatch:
1239     case ASTReader::ConfigurationMismatch:
1240     case ASTReader::HadErrors:
1241       ModuleLoader::HadFatalFailure = true;
1242       // FIXME: The ASTReader will already have complained, but can we showhorn
1243       // that diagnostic information into a more useful form?
1244       KnownModules[Path[0].first] = 0;
1245       return ModuleLoadResult();
1246 
1247     case ASTReader::Failure:
1248       ModuleLoader::HadFatalFailure = true;
1249       // Already complained, but note now that we failed.
1250       KnownModules[Path[0].first] = 0;
1251       ModuleBuildFailed = true;
1252       return ModuleLoadResult();
1253     }
1254 
1255     // Cache the result of this top-level module lookup for later.
1256     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1257   }
1258 
1259   // If we never found the module, fail.
1260   if (!Module)
1261     return ModuleLoadResult();
1262 
1263   // Verify that the rest of the module path actually corresponds to
1264   // a submodule.
1265   if (Path.size() > 1) {
1266     for (unsigned I = 1, N = Path.size(); I != N; ++I) {
1267       StringRef Name = Path[I].first->getName();
1268       clang::Module *Sub = Module->findSubmodule(Name);
1269 
1270       if (!Sub) {
1271         // Attempt to perform typo correction to find a module name that works.
1272         SmallVector<StringRef, 2> Best;
1273         unsigned BestEditDistance = (std::numeric_limits<unsigned>::max)();
1274 
1275         for (clang::Module::submodule_iterator J = Module->submodule_begin(),
1276                                             JEnd = Module->submodule_end();
1277              J != JEnd; ++J) {
1278           unsigned ED = Name.edit_distance((*J)->Name,
1279                                            /*AllowReplacements=*/true,
1280                                            BestEditDistance);
1281           if (ED <= BestEditDistance) {
1282             if (ED < BestEditDistance) {
1283               Best.clear();
1284               BestEditDistance = ED;
1285             }
1286 
1287             Best.push_back((*J)->Name);
1288           }
1289         }
1290 
1291         // If there was a clear winner, user it.
1292         if (Best.size() == 1) {
1293           getDiagnostics().Report(Path[I].second,
1294                                   diag::err_no_submodule_suggest)
1295             << Path[I].first << Module->getFullModuleName() << Best[0]
1296             << SourceRange(Path[0].second, Path[I-1].second)
1297             << FixItHint::CreateReplacement(SourceRange(Path[I].second),
1298                                             Best[0]);
1299 
1300           Sub = Module->findSubmodule(Best[0]);
1301         }
1302       }
1303 
1304       if (!Sub) {
1305         // No submodule by this name. Complain, and don't look for further
1306         // submodules.
1307         getDiagnostics().Report(Path[I].second, diag::err_no_submodule)
1308           << Path[I].first << Module->getFullModuleName()
1309           << SourceRange(Path[0].second, Path[I-1].second);
1310         break;
1311       }
1312 
1313       Module = Sub;
1314     }
1315   }
1316 
1317   // Make the named module visible, if it's not already part of the module
1318   // we are parsing.
1319   if (ModuleName != getLangOpts().CurrentModule) {
1320     if (!Module->IsFromModuleFile) {
1321       // We have an umbrella header or directory that doesn't actually include
1322       // all of the headers within the directory it covers. Complain about
1323       // this missing submodule and recover by forgetting that we ever saw
1324       // this submodule.
1325       // FIXME: Should we detect this at module load time? It seems fairly
1326       // expensive (and rare).
1327       getDiagnostics().Report(ImportLoc, diag::warn_missing_submodule)
1328         << Module->getFullModuleName()
1329         << SourceRange(Path.front().second, Path.back().second);
1330 
1331       return ModuleLoadResult(0, true);
1332     }
1333 
1334     // Check whether this module is available.
1335     clang::Module::Requirement Requirement;
1336     clang::Module::HeaderDirective MissingHeader;
1337     if (!Module->isAvailable(getLangOpts(), getTarget(), Requirement,
1338                              MissingHeader)) {
1339       if (MissingHeader.FileNameLoc.isValid()) {
1340         getDiagnostics().Report(MissingHeader.FileNameLoc,
1341                                 diag::err_module_header_missing)
1342           << MissingHeader.IsUmbrella << MissingHeader.FileName;
1343       } else {
1344         getDiagnostics().Report(ImportLoc, diag::err_module_unavailable)
1345           << Module->getFullModuleName()
1346           << Requirement.second << Requirement.first
1347           << SourceRange(Path.front().second, Path.back().second);
1348       }
1349       LastModuleImportLoc = ImportLoc;
1350       LastModuleImportResult = ModuleLoadResult();
1351       return ModuleLoadResult();
1352     }
1353 
1354     ModuleManager->makeModuleVisible(Module, Visibility, ImportLoc,
1355                                      /*Complain=*/true);
1356   }
1357 
1358   // Check for any configuration macros that have changed.
1359   clang::Module *TopModule = Module->getTopLevelModule();
1360   for (unsigned I = 0, N = TopModule->ConfigMacros.size(); I != N; ++I) {
1361     checkConfigMacro(getPreprocessor(), TopModule->ConfigMacros[I],
1362                      Module, ImportLoc);
1363   }
1364 
1365   // If this module import was due to an inclusion directive, create an
1366   // implicit import declaration to capture it in the AST.
1367   if (IsInclusionDirective && hasASTContext()) {
1368     TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
1369     ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
1370                                                      ImportLoc, Module,
1371                                                      Path.back().second);
1372     TU->addDecl(ImportD);
1373     if (Consumer)
1374       Consumer->HandleImplicitImportDecl(ImportD);
1375   }
1376 
1377   LastModuleImportLoc = ImportLoc;
1378   LastModuleImportResult = ModuleLoadResult(Module, false);
1379   return LastModuleImportResult;
1380 }
1381 
1382 void CompilerInstance::makeModuleVisible(Module *Mod,
1383                                          Module::NameVisibilityKind Visibility,
1384                                          SourceLocation ImportLoc,
1385                                          bool Complain){
1386   ModuleManager->makeModuleVisible(Mod, Visibility, ImportLoc, Complain);
1387 }
1388 
1389