xref: /llvm-project/clang/lib/Frontend/CompilerInstance.cpp (revision 841f1c782e2aba329e329ae6054266ce874ef49c)
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     AttachDependencyFileGen(*PP, DepOpts);
273   if (!DepOpts.DOTOutputFile.empty())
274     AttachDependencyGraphGen(*PP, DepOpts.DOTOutputFile,
275                              getHeaderSearchOpts().Sysroot);
276 
277 
278   // Handle generating header include information, if requested.
279   if (DepOpts.ShowHeaderIncludes)
280     AttachHeaderIncludeGen(*PP);
281   if (!DepOpts.HeaderIncludeOutputFile.empty()) {
282     StringRef OutputPath = DepOpts.HeaderIncludeOutputFile;
283     if (OutputPath == "-")
284       OutputPath = "";
285     AttachHeaderIncludeGen(*PP, /*ShowAllHeaders=*/true, OutputPath,
286                            /*ShowDepth=*/false);
287   }
288 
289   if (DepOpts.PrintShowIncludes) {
290     AttachHeaderIncludeGen(*PP, /*ShowAllHeaders=*/false, /*OutputPath=*/"",
291                            /*ShowDepth=*/true, /*MSStyle=*/true);
292   }
293 }
294 
295 // ASTContext
296 
297 void CompilerInstance::createASTContext() {
298   Preprocessor &PP = getPreprocessor();
299   Context = new ASTContext(getLangOpts(), PP.getSourceManager(),
300                            &getTarget(), PP.getIdentifierTable(),
301                            PP.getSelectorTable(), PP.getBuiltinInfo(),
302                            /*size_reserve=*/ 0);
303 }
304 
305 // ExternalASTSource
306 
307 void CompilerInstance::createPCHExternalASTSource(StringRef Path,
308                                                   bool DisablePCHValidation,
309                                                 bool AllowPCHWithCompilerErrors,
310                                                  void *DeserializationListener){
311   IntrusiveRefCntPtr<ExternalASTSource> Source;
312   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
313   Source = createPCHExternalASTSource(Path, getHeaderSearchOpts().Sysroot,
314                                           DisablePCHValidation,
315                                           AllowPCHWithCompilerErrors,
316                                           getPreprocessor(), getASTContext(),
317                                           DeserializationListener,
318                                           Preamble,
319                                        getFrontendOpts().UseGlobalModuleIndex);
320   ModuleManager = static_cast<ASTReader*>(Source.getPtr());
321   getASTContext().setExternalSource(Source);
322 }
323 
324 ExternalASTSource *
325 CompilerInstance::createPCHExternalASTSource(StringRef Path,
326                                              const std::string &Sysroot,
327                                              bool DisablePCHValidation,
328                                              bool AllowPCHWithCompilerErrors,
329                                              Preprocessor &PP,
330                                              ASTContext &Context,
331                                              void *DeserializationListener,
332                                              bool Preamble,
333                                              bool UseGlobalModuleIndex) {
334   OwningPtr<ASTReader> Reader;
335   Reader.reset(new ASTReader(PP, Context,
336                              Sysroot.empty() ? "" : Sysroot.c_str(),
337                              DisablePCHValidation,
338                              AllowPCHWithCompilerErrors,
339                              /*AllowConfigurationMismatch*/false,
340                              /*ValidateSystemInputs*/false,
341                              UseGlobalModuleIndex));
342 
343   Reader->setDeserializationListener(
344             static_cast<ASTDeserializationListener *>(DeserializationListener));
345   switch (Reader->ReadAST(Path,
346                           Preamble ? serialization::MK_Preamble
347                                    : serialization::MK_PCH,
348                           SourceLocation(),
349                           ASTReader::ARR_None)) {
350   case ASTReader::Success:
351     // Set the predefines buffer as suggested by the PCH reader. Typically, the
352     // predefines buffer will be empty.
353     PP.setPredefines(Reader->getSuggestedPredefines());
354     return Reader.take();
355 
356   case ASTReader::Failure:
357     // Unrecoverable failure: don't even try to process the input file.
358     break;
359 
360   case ASTReader::Missing:
361   case ASTReader::OutOfDate:
362   case ASTReader::VersionMismatch:
363   case ASTReader::ConfigurationMismatch:
364   case ASTReader::HadErrors:
365     // No suitable PCH file could be found. Return an error.
366     break;
367   }
368 
369   return 0;
370 }
371 
372 // Code Completion
373 
374 static bool EnableCodeCompletion(Preprocessor &PP,
375                                  const std::string &Filename,
376                                  unsigned Line,
377                                  unsigned Column) {
378   // Tell the source manager to chop off the given file at a specific
379   // line and column.
380   const FileEntry *Entry = PP.getFileManager().getFile(Filename);
381   if (!Entry) {
382     PP.getDiagnostics().Report(diag::err_fe_invalid_code_complete_file)
383       << Filename;
384     return true;
385   }
386 
387   // Truncate the named file at the given line/column.
388   PP.SetCodeCompletionPoint(Entry, Line, Column);
389   return false;
390 }
391 
392 void CompilerInstance::createCodeCompletionConsumer() {
393   const ParsedSourceLocation &Loc = getFrontendOpts().CodeCompletionAt;
394   if (!CompletionConsumer) {
395     setCodeCompletionConsumer(
396       createCodeCompletionConsumer(getPreprocessor(),
397                                    Loc.FileName, Loc.Line, Loc.Column,
398                                    getFrontendOpts().CodeCompleteOpts,
399                                    llvm::outs()));
400     if (!CompletionConsumer)
401       return;
402   } else if (EnableCodeCompletion(getPreprocessor(), Loc.FileName,
403                                   Loc.Line, Loc.Column)) {
404     setCodeCompletionConsumer(0);
405     return;
406   }
407 
408   if (CompletionConsumer->isOutputBinary() &&
409       llvm::sys::ChangeStdoutToBinary()) {
410     getPreprocessor().getDiagnostics().Report(diag::err_fe_stdout_binary);
411     setCodeCompletionConsumer(0);
412   }
413 }
414 
415 void CompilerInstance::createFrontendTimer() {
416   FrontendTimer.reset(new llvm::Timer("Clang front-end timer"));
417 }
418 
419 CodeCompleteConsumer *
420 CompilerInstance::createCodeCompletionConsumer(Preprocessor &PP,
421                                                const std::string &Filename,
422                                                unsigned Line,
423                                                unsigned Column,
424                                                const CodeCompleteOptions &Opts,
425                                                raw_ostream &OS) {
426   if (EnableCodeCompletion(PP, Filename, Line, Column))
427     return 0;
428 
429   // Set up the creation routine for code-completion.
430   return new PrintingCodeCompleteConsumer(Opts, OS);
431 }
432 
433 void CompilerInstance::createSema(TranslationUnitKind TUKind,
434                                   CodeCompleteConsumer *CompletionConsumer) {
435   TheSema.reset(new Sema(getPreprocessor(), getASTContext(), getASTConsumer(),
436                          TUKind, CompletionConsumer));
437 }
438 
439 // Output Files
440 
441 void CompilerInstance::addOutputFile(const OutputFile &OutFile) {
442   assert(OutFile.OS && "Attempt to add empty stream to output list!");
443   OutputFiles.push_back(OutFile);
444 }
445 
446 void CompilerInstance::clearOutputFiles(bool EraseFiles) {
447   for (std::list<OutputFile>::iterator
448          it = OutputFiles.begin(), ie = OutputFiles.end(); it != ie; ++it) {
449     delete it->OS;
450     if (!it->TempFilename.empty()) {
451       if (EraseFiles) {
452         llvm::sys::fs::remove(it->TempFilename);
453       } else {
454         SmallString<128> NewOutFile(it->Filename);
455 
456         // If '-working-directory' was passed, the output filename should be
457         // relative to that.
458         FileMgr->FixupRelativePath(NewOutFile);
459         if (llvm::error_code ec = llvm::sys::fs::rename(it->TempFilename,
460                                                         NewOutFile.str())) {
461           getDiagnostics().Report(diag::err_unable_to_rename_temp)
462             << it->TempFilename << it->Filename << ec.message();
463 
464           llvm::sys::fs::remove(it->TempFilename);
465         }
466       }
467     } else if (!it->Filename.empty() && EraseFiles)
468       llvm::sys::fs::remove(it->Filename);
469 
470   }
471   OutputFiles.clear();
472 }
473 
474 llvm::raw_fd_ostream *
475 CompilerInstance::createDefaultOutputFile(bool Binary,
476                                           StringRef InFile,
477                                           StringRef Extension) {
478   return createOutputFile(getFrontendOpts().OutputFile, Binary,
479                           /*RemoveFileOnSignal=*/true, InFile, Extension,
480                           /*UseTemporary=*/true);
481 }
482 
483 llvm::raw_fd_ostream *
484 CompilerInstance::createOutputFile(StringRef OutputPath,
485                                    bool Binary, bool RemoveFileOnSignal,
486                                    StringRef InFile,
487                                    StringRef Extension,
488                                    bool UseTemporary,
489                                    bool CreateMissingDirectories) {
490   std::string Error, OutputPathName, TempPathName;
491   llvm::raw_fd_ostream *OS = createOutputFile(OutputPath, Error, Binary,
492                                               RemoveFileOnSignal,
493                                               InFile, Extension,
494                                               UseTemporary,
495                                               CreateMissingDirectories,
496                                               &OutputPathName,
497                                               &TempPathName);
498   if (!OS) {
499     getDiagnostics().Report(diag::err_fe_unable_to_open_output)
500       << OutputPath << Error;
501     return 0;
502   }
503 
504   // Add the output file -- but don't try to remove "-", since this means we are
505   // using stdin.
506   addOutputFile(OutputFile((OutputPathName != "-") ? OutputPathName : "",
507                 TempPathName, OS));
508 
509   return OS;
510 }
511 
512 llvm::raw_fd_ostream *
513 CompilerInstance::createOutputFile(StringRef OutputPath,
514                                    std::string &Error,
515                                    bool Binary,
516                                    bool RemoveFileOnSignal,
517                                    StringRef InFile,
518                                    StringRef Extension,
519                                    bool UseTemporary,
520                                    bool CreateMissingDirectories,
521                                    std::string *ResultPathName,
522                                    std::string *TempPathName) {
523   assert((!CreateMissingDirectories || UseTemporary) &&
524          "CreateMissingDirectories is only allowed when using temporary files");
525 
526   std::string OutFile, TempFile;
527   if (!OutputPath.empty()) {
528     OutFile = OutputPath;
529   } else if (InFile == "-") {
530     OutFile = "-";
531   } else if (!Extension.empty()) {
532     SmallString<128> Path(InFile);
533     llvm::sys::path::replace_extension(Path, Extension);
534     OutFile = Path.str();
535   } else {
536     OutFile = "-";
537   }
538 
539   OwningPtr<llvm::raw_fd_ostream> OS;
540   std::string OSFile;
541 
542   if (UseTemporary) {
543     if (OutFile == "-")
544       UseTemporary = false;
545     else {
546       llvm::sys::fs::file_status Status;
547       llvm::sys::fs::status(OutputPath, Status);
548       if (llvm::sys::fs::exists(Status)) {
549         // Fail early if we can't write to the final destination.
550         if (!llvm::sys::fs::can_write(OutputPath))
551           return 0;
552 
553         // Don't use a temporary if the output is a special file. This handles
554         // things like '-o /dev/null'
555         if (!llvm::sys::fs::is_regular_file(Status))
556           UseTemporary = false;
557       }
558     }
559   }
560 
561   if (UseTemporary) {
562     // Create a temporary file.
563     SmallString<128> TempPath;
564     TempPath = OutFile;
565     TempPath += "-%%%%%%%%";
566     int fd;
567     llvm::error_code EC =
568         llvm::sys::fs::createUniqueFile(TempPath.str(), fd, TempPath);
569 
570     if (CreateMissingDirectories &&
571         EC == llvm::errc::no_such_file_or_directory) {
572       StringRef Parent = llvm::sys::path::parent_path(OutputPath);
573       EC = llvm::sys::fs::create_directories(Parent);
574       if (!EC) {
575         EC = llvm::sys::fs::createUniqueFile(TempPath.str(), fd, TempPath);
576       }
577     }
578 
579     if (!EC) {
580       OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
581       OSFile = TempFile = TempPath.str();
582     }
583     // If we failed to create the temporary, fallback to writing to the file
584     // directly. This handles the corner case where we cannot write to the
585     // directory, but can write to the file.
586   }
587 
588   if (!OS) {
589     OSFile = OutFile;
590     OS.reset(new llvm::raw_fd_ostream(
591         OSFile.c_str(), Error,
592         (Binary ? llvm::sys::fs::F_None : llvm::sys::fs::F_Text)));
593     if (!Error.empty())
594       return 0;
595   }
596 
597   // Make sure the out stream file gets removed if we crash.
598   if (RemoveFileOnSignal)
599     llvm::sys::RemoveFileOnSignal(OSFile);
600 
601   if (ResultPathName)
602     *ResultPathName = OutFile;
603   if (TempPathName)
604     *TempPathName = TempFile;
605 
606   return OS.take();
607 }
608 
609 // Initialization Utilities
610 
611 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input){
612   return InitializeSourceManager(Input, getDiagnostics(),
613                                  getFileManager(), getSourceManager(),
614                                  getFrontendOpts());
615 }
616 
617 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input,
618                                                DiagnosticsEngine &Diags,
619                                                FileManager &FileMgr,
620                                                SourceManager &SourceMgr,
621                                                const FrontendOptions &Opts) {
622   SrcMgr::CharacteristicKind
623     Kind = Input.isSystem() ? SrcMgr::C_System : SrcMgr::C_User;
624 
625   if (Input.isBuffer()) {
626     SourceMgr.createMainFileIDForMemBuffer(Input.getBuffer(), Kind);
627     assert(!SourceMgr.getMainFileID().isInvalid() &&
628            "Couldn't establish MainFileID!");
629     return true;
630   }
631 
632   StringRef InputFile = Input.getFile();
633 
634   // Figure out where to get and map in the main file.
635   if (InputFile != "-") {
636     const FileEntry *File = FileMgr.getFile(InputFile, /*OpenFile=*/true);
637     if (!File) {
638       Diags.Report(diag::err_fe_error_reading) << InputFile;
639       return false;
640     }
641 
642     // The natural SourceManager infrastructure can't currently handle named
643     // pipes, but we would at least like to accept them for the main
644     // file. Detect them here, read them with the volatile flag so FileMgr will
645     // pick up the correct size, and simply override their contents as we do for
646     // STDIN.
647     if (File->isNamedPipe()) {
648       std::string ErrorStr;
649       if (llvm::MemoryBuffer *MB =
650               FileMgr.getBufferForFile(File, &ErrorStr, /*isVolatile=*/true)) {
651         // Create a new virtual file that will have the correct size.
652         File = FileMgr.getVirtualFile(InputFile, MB->getBufferSize(), 0);
653         SourceMgr.overrideFileContents(File, MB);
654       } else {
655         Diags.Report(diag::err_cannot_open_file) << InputFile << ErrorStr;
656         return false;
657       }
658     }
659 
660     SourceMgr.createMainFileID(File, Kind);
661   } else {
662     OwningPtr<llvm::MemoryBuffer> SB;
663     if (llvm::error_code ec = llvm::MemoryBuffer::getSTDIN(SB)) {
664       Diags.Report(diag::err_fe_error_reading_stdin) << ec.message();
665       return false;
666     }
667     const FileEntry *File = FileMgr.getVirtualFile(SB->getBufferIdentifier(),
668                                                    SB->getBufferSize(), 0);
669     SourceMgr.createMainFileID(File, Kind);
670     SourceMgr.overrideFileContents(File, SB.take());
671   }
672 
673   assert(!SourceMgr.getMainFileID().isInvalid() &&
674          "Couldn't establish MainFileID!");
675   return true;
676 }
677 
678 // High-Level Operations
679 
680 bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
681   assert(hasDiagnostics() && "Diagnostics engine is not initialized!");
682   assert(!getFrontendOpts().ShowHelp && "Client must handle '-help'!");
683   assert(!getFrontendOpts().ShowVersion && "Client must handle '-version'!");
684 
685   // FIXME: Take this as an argument, once all the APIs we used have moved to
686   // taking it as an input instead of hard-coding llvm::errs.
687   raw_ostream &OS = llvm::errs();
688 
689   // Create the target instance.
690   setTarget(TargetInfo::CreateTargetInfo(getDiagnostics(), &getTargetOpts()));
691   if (!hasTarget())
692     return false;
693 
694   // Inform the target of the language options.
695   //
696   // FIXME: We shouldn't need to do this, the target should be immutable once
697   // created. This complexity should be lifted elsewhere.
698   getTarget().setForcedLangOptions(getLangOpts());
699 
700   // rewriter project will change target built-in bool type from its default.
701   if (getFrontendOpts().ProgramAction == frontend::RewriteObjC)
702     getTarget().noSignedCharForObjCBool();
703 
704   // Validate/process some options.
705   if (getHeaderSearchOpts().Verbose)
706     OS << "clang -cc1 version " CLANG_VERSION_STRING
707        << " based upon " << PACKAGE_STRING
708        << " default target " << llvm::sys::getDefaultTargetTriple() << "\n";
709 
710   if (getFrontendOpts().ShowTimers)
711     createFrontendTimer();
712 
713   if (getFrontendOpts().ShowStats)
714     llvm::EnableStatistics();
715 
716   for (unsigned i = 0, e = getFrontendOpts().Inputs.size(); i != e; ++i) {
717     // Reset the ID tables if we are reusing the SourceManager.
718     if (hasSourceManager())
719       getSourceManager().clearIDTables();
720 
721     if (Act.BeginSourceFile(*this, getFrontendOpts().Inputs[i])) {
722       Act.Execute();
723       Act.EndSourceFile();
724     }
725   }
726 
727   // Notify the diagnostic client that all files were processed.
728   getDiagnostics().getClient()->finish();
729 
730   if (getDiagnosticOpts().ShowCarets) {
731     // We can have multiple diagnostics sharing one diagnostic client.
732     // Get the total number of warnings/errors from the client.
733     unsigned NumWarnings = getDiagnostics().getClient()->getNumWarnings();
734     unsigned NumErrors = getDiagnostics().getClient()->getNumErrors();
735 
736     if (NumWarnings)
737       OS << NumWarnings << " warning" << (NumWarnings == 1 ? "" : "s");
738     if (NumWarnings && NumErrors)
739       OS << " and ";
740     if (NumErrors)
741       OS << NumErrors << " error" << (NumErrors == 1 ? "" : "s");
742     if (NumWarnings || NumErrors)
743       OS << " generated.\n";
744   }
745 
746   if (getFrontendOpts().ShowStats && hasFileManager()) {
747     getFileManager().PrintStats();
748     OS << "\n";
749   }
750 
751   return !getDiagnostics().getClient()->getNumErrors();
752 }
753 
754 /// \brief Determine the appropriate source input kind based on language
755 /// options.
756 static InputKind getSourceInputKindFromOptions(const LangOptions &LangOpts) {
757   if (LangOpts.OpenCL)
758     return IK_OpenCL;
759   if (LangOpts.CUDA)
760     return IK_CUDA;
761   if (LangOpts.ObjC1)
762     return LangOpts.CPlusPlus? IK_ObjCXX : IK_ObjC;
763   return LangOpts.CPlusPlus? IK_CXX : IK_C;
764 }
765 
766 /// \brief Compile a module file for the given module, using the options
767 /// provided by the importing compiler instance.
768 static void compileModule(CompilerInstance &ImportingInstance,
769                           SourceLocation ImportLoc,
770                           Module *Module,
771                           StringRef ModuleFileName) {
772   // FIXME: have LockFileManager return an error_code so that we can
773   // avoid the mkdir when the directory already exists.
774   StringRef Dir = llvm::sys::path::parent_path(ModuleFileName);
775   llvm::sys::fs::create_directories(Dir);
776 
777   llvm::LockFileManager Locked(ModuleFileName);
778   switch (Locked) {
779   case llvm::LockFileManager::LFS_Error:
780     return;
781 
782   case llvm::LockFileManager::LFS_Owned:
783     // We're responsible for building the module ourselves. Do so below.
784     break;
785 
786   case llvm::LockFileManager::LFS_Shared:
787     // Someone else is responsible for building the module. Wait for them to
788     // finish.
789     Locked.waitForUnlock();
790     return;
791   }
792 
793   ModuleMap &ModMap
794     = ImportingInstance.getPreprocessor().getHeaderSearchInfo().getModuleMap();
795 
796   // Construct a compiler invocation for creating this module.
797   IntrusiveRefCntPtr<CompilerInvocation> Invocation
798     (new CompilerInvocation(ImportingInstance.getInvocation()));
799 
800   PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
801 
802   // For any options that aren't intended to affect how a module is built,
803   // reset them to their default values.
804   Invocation->getLangOpts()->resetNonModularOptions();
805   PPOpts.resetNonModularOptions();
806 
807   // Remove any macro definitions that are explicitly ignored by the module.
808   // They aren't supposed to affect how the module is built anyway.
809   const HeaderSearchOptions &HSOpts = Invocation->getHeaderSearchOpts();
810   PPOpts.Macros.erase(
811       std::remove_if(PPOpts.Macros.begin(), PPOpts.Macros.end(),
812                      [&HSOpts](const std::pair<std::string, bool> &def) {
813         StringRef MacroDef = def.first;
814         return HSOpts.ModulesIgnoreMacros.count(MacroDef.split('=').first) > 0;
815       }),
816       PPOpts.Macros.end());
817 
818   // Note the name of the module we're building.
819   Invocation->getLangOpts()->CurrentModule = Module->getTopLevelModuleName();
820 
821   // Make sure that the failed-module structure has been allocated in
822   // the importing instance, and propagate the pointer to the newly-created
823   // instance.
824   PreprocessorOptions &ImportingPPOpts
825     = ImportingInstance.getInvocation().getPreprocessorOpts();
826   if (!ImportingPPOpts.FailedModules)
827     ImportingPPOpts.FailedModules = new PreprocessorOptions::FailedModulesSet;
828   PPOpts.FailedModules = ImportingPPOpts.FailedModules;
829 
830   // If there is a module map file, build the module using the module map.
831   // Set up the inputs/outputs so that we build the module from its umbrella
832   // header.
833   FrontendOptions &FrontendOpts = Invocation->getFrontendOpts();
834   FrontendOpts.OutputFile = ModuleFileName.str();
835   FrontendOpts.DisableFree = false;
836   FrontendOpts.GenerateGlobalModuleIndex = false;
837   FrontendOpts.Inputs.clear();
838   InputKind IK = getSourceInputKindFromOptions(*Invocation->getLangOpts());
839 
840   // Don't free the remapped file buffers; they are owned by our caller.
841   PPOpts.RetainRemappedFileBuffers = true;
842 
843   Invocation->getDiagnosticOpts().VerifyDiagnostics = 0;
844   assert(ImportingInstance.getInvocation().getModuleHash() ==
845          Invocation->getModuleHash() && "Module hash mismatch!");
846 
847   // Construct a compiler instance that will be used to actually create the
848   // module.
849   CompilerInstance Instance;
850   Instance.setInvocation(&*Invocation);
851 
852   Instance.createDiagnostics(new ForwardingDiagnosticConsumer(
853                                    ImportingInstance.getDiagnosticClient()),
854                              /*ShouldOwnClient=*/true);
855 
856   Instance.setVirtualFileSystem(&ImportingInstance.getVirtualFileSystem());
857 
858   // Note that this module is part of the module build stack, so that we
859   // can detect cycles in the module graph.
860   Instance.setFileManager(&ImportingInstance.getFileManager());
861   Instance.createSourceManager(Instance.getFileManager());
862   SourceManager &SourceMgr = Instance.getSourceManager();
863   SourceMgr.setModuleBuildStack(
864     ImportingInstance.getSourceManager().getModuleBuildStack());
865   SourceMgr.pushModuleBuildStack(Module->getTopLevelModuleName(),
866     FullSourceLoc(ImportLoc, ImportingInstance.getSourceManager()));
867 
868   // Get or create the module map that we'll use to build this module.
869   std::string InferredModuleMapContent;
870   if (const FileEntry *ModuleMapFile =
871           ModMap.getContainingModuleMapFile(Module)) {
872     // Use the module map where this module resides.
873     FrontendOpts.Inputs.push_back(
874         FrontendInputFile(ModuleMapFile->getName(), IK));
875   } else {
876     llvm::raw_string_ostream OS(InferredModuleMapContent);
877     Module->print(OS);
878     OS.flush();
879     FrontendOpts.Inputs.push_back(
880         FrontendInputFile("__inferred_module.map", IK));
881 
882     const llvm::MemoryBuffer *ModuleMapBuffer =
883         llvm::MemoryBuffer::getMemBuffer(InferredModuleMapContent);
884     ModuleMapFile = Instance.getFileManager().getVirtualFile(
885         "__inferred_module.map", InferredModuleMapContent.size(), 0);
886     SourceMgr.overrideFileContents(ModuleMapFile, ModuleMapBuffer);
887   }
888 
889   // Construct a module-generating action.
890   GenerateModuleAction CreateModuleAction(Module->IsSystem);
891 
892   // Execute the action to actually build the module in-place. Use a separate
893   // thread so that we get a stack large enough.
894   const unsigned ThreadStackSize = 8 << 20;
895   llvm::CrashRecoveryContext CRC;
896   CRC.RunSafelyOnThread([&]() { Instance.ExecuteAction(CreateModuleAction); },
897                         ThreadStackSize);
898 
899   // Delete the temporary module map file.
900   // FIXME: Even though we're executing under crash protection, it would still
901   // be nice to do this with RemoveFileOnSignal when we can. However, that
902   // doesn't make sense for all clients, so clean this up manually.
903   Instance.clearOutputFiles(/*EraseFiles=*/true);
904 
905   // We've rebuilt a module. If we're allowed to generate or update the global
906   // module index, record that fact in the importing compiler instance.
907   if (ImportingInstance.getFrontendOpts().GenerateGlobalModuleIndex) {
908     ImportingInstance.setBuildGlobalModuleIndex(true);
909   }
910 }
911 
912 /// \brief Diagnose differences between the current definition of the given
913 /// configuration macro and the definition provided on the command line.
914 static void checkConfigMacro(Preprocessor &PP, StringRef ConfigMacro,
915                              Module *Mod, SourceLocation ImportLoc) {
916   IdentifierInfo *Id = PP.getIdentifierInfo(ConfigMacro);
917   SourceManager &SourceMgr = PP.getSourceManager();
918 
919   // If this identifier has never had a macro definition, then it could
920   // not have changed.
921   if (!Id->hadMacroDefinition())
922     return;
923 
924   // If this identifier does not currently have a macro definition,
925   // check whether it had one on the command line.
926   if (!Id->hasMacroDefinition()) {
927     MacroDirective::DefInfo LatestDef =
928         PP.getMacroDirectiveHistory(Id)->getDefinition();
929     for (MacroDirective::DefInfo Def = LatestDef; Def;
930            Def = Def.getPreviousDefinition()) {
931       FileID FID = SourceMgr.getFileID(Def.getLocation());
932       if (FID.isInvalid())
933         continue;
934 
935       // We only care about the predefines buffer.
936       if (FID != PP.getPredefinesFileID())
937         continue;
938 
939       // This macro was defined on the command line, then #undef'd later.
940       // Complain.
941       PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
942         << true << ConfigMacro << Mod->getFullModuleName();
943       if (LatestDef.isUndefined())
944         PP.Diag(LatestDef.getUndefLocation(), diag::note_module_def_undef_here)
945           << true;
946       return;
947     }
948 
949     // Okay: no definition in the predefines buffer.
950     return;
951   }
952 
953   // This identifier has a macro definition. Check whether we had a definition
954   // on the command line.
955   MacroDirective::DefInfo LatestDef =
956       PP.getMacroDirectiveHistory(Id)->getDefinition();
957   MacroDirective::DefInfo PredefinedDef;
958   for (MacroDirective::DefInfo Def = LatestDef; Def;
959          Def = Def.getPreviousDefinition()) {
960     FileID FID = SourceMgr.getFileID(Def.getLocation());
961     if (FID.isInvalid())
962       continue;
963 
964     // We only care about the predefines buffer.
965     if (FID != PP.getPredefinesFileID())
966       continue;
967 
968     PredefinedDef = Def;
969     break;
970   }
971 
972   // If there was no definition for this macro in the predefines buffer,
973   // complain.
974   if (!PredefinedDef ||
975       (!PredefinedDef.getLocation().isValid() &&
976        PredefinedDef.getUndefLocation().isValid())) {
977     PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
978       << false << ConfigMacro << Mod->getFullModuleName();
979     PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
980       << false;
981     return;
982   }
983 
984   // If the current macro definition is the same as the predefined macro
985   // definition, it's okay.
986   if (LatestDef.getMacroInfo() == PredefinedDef.getMacroInfo() ||
987       LatestDef.getMacroInfo()->isIdenticalTo(*PredefinedDef.getMacroInfo(),PP,
988                                               /*Syntactically=*/true))
989     return;
990 
991   // The macro definitions differ.
992   PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
993     << false << ConfigMacro << Mod->getFullModuleName();
994   PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
995     << false;
996 }
997 
998 /// \brief Write a new timestamp file with the given path.
999 static void writeTimestampFile(StringRef TimestampFile) {
1000   std::string ErrorInfo;
1001   llvm::raw_fd_ostream Out(TimestampFile.str().c_str(), ErrorInfo,
1002                            llvm::sys::fs::F_None);
1003 }
1004 
1005 /// \brief Prune the module cache of modules that haven't been accessed in
1006 /// a long time.
1007 static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
1008   struct stat StatBuf;
1009   llvm::SmallString<128> TimestampFile;
1010   TimestampFile = HSOpts.ModuleCachePath;
1011   llvm::sys::path::append(TimestampFile, "modules.timestamp");
1012 
1013   // Try to stat() the timestamp file.
1014   if (::stat(TimestampFile.c_str(), &StatBuf)) {
1015     // If the timestamp file wasn't there, create one now.
1016     if (errno == ENOENT) {
1017       writeTimestampFile(TimestampFile);
1018     }
1019     return;
1020   }
1021 
1022   // Check whether the time stamp is older than our pruning interval.
1023   // If not, do nothing.
1024   time_t TimeStampModTime = StatBuf.st_mtime;
1025   time_t CurrentTime = time(0);
1026   if (CurrentTime - TimeStampModTime <= time_t(HSOpts.ModuleCachePruneInterval))
1027     return;
1028 
1029   // Write a new timestamp file so that nobody else attempts to prune.
1030   // There is a benign race condition here, if two Clang instances happen to
1031   // notice at the same time that the timestamp is out-of-date.
1032   writeTimestampFile(TimestampFile);
1033 
1034   // Walk the entire module cache, looking for unused module files and module
1035   // indices.
1036   llvm::error_code EC;
1037   SmallString<128> ModuleCachePathNative;
1038   llvm::sys::path::native(HSOpts.ModuleCachePath, ModuleCachePathNative);
1039   for (llvm::sys::fs::directory_iterator
1040          Dir(ModuleCachePathNative.str(), EC), DirEnd;
1041        Dir != DirEnd && !EC; Dir.increment(EC)) {
1042     // If we don't have a directory, there's nothing to look into.
1043     if (!llvm::sys::fs::is_directory(Dir->path()))
1044       continue;
1045 
1046     // Walk all of the files within this directory.
1047     for (llvm::sys::fs::directory_iterator File(Dir->path(), EC), FileEnd;
1048          File != FileEnd && !EC; File.increment(EC)) {
1049       // We only care about module and global module index files.
1050       StringRef Extension = llvm::sys::path::extension(File->path());
1051       if (Extension != ".pcm" && Extension != ".timestamp" &&
1052           llvm::sys::path::filename(File->path()) != "modules.idx")
1053         continue;
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         continue;
1059 
1060       // If the file has been used recently enough, leave it there.
1061       time_t FileAccessTime = StatBuf.st_atime;
1062       if (CurrentTime - FileAccessTime <=
1063               time_t(HSOpts.ModuleCachePruneAfter)) {
1064         continue;
1065       }
1066 
1067       // Remove the file.
1068       llvm::sys::fs::remove(File->path());
1069 
1070       // Remove the timestamp file.
1071       std::string TimpestampFilename = File->path() + ".timestamp";
1072       llvm::sys::fs::remove(TimpestampFilename);
1073     }
1074 
1075     // If we removed all of the files in the directory, remove the directory
1076     // itself.
1077     if (llvm::sys::fs::directory_iterator(Dir->path(), EC) ==
1078             llvm::sys::fs::directory_iterator() && !EC)
1079       llvm::sys::fs::remove(Dir->path());
1080   }
1081 }
1082 
1083 ModuleLoadResult
1084 CompilerInstance::loadModule(SourceLocation ImportLoc,
1085                              ModuleIdPath Path,
1086                              Module::NameVisibilityKind Visibility,
1087                              bool IsInclusionDirective) {
1088   // Determine what file we're searching from.
1089   StringRef ModuleName = Path[0].first->getName();
1090   SourceLocation ModuleNameLoc = Path[0].second;
1091 
1092   // If we've already handled this import, just return the cached result.
1093   // This one-element cache is important to eliminate redundant diagnostics
1094   // when both the preprocessor and parser see the same import declaration.
1095   if (!ImportLoc.isInvalid() && LastModuleImportLoc == ImportLoc) {
1096     // Make the named module visible.
1097     if (LastModuleImportResult && ModuleName != getLangOpts().CurrentModule)
1098       ModuleManager->makeModuleVisible(LastModuleImportResult, Visibility,
1099                                        ImportLoc, /*Complain=*/false);
1100     return LastModuleImportResult;
1101   }
1102 
1103   clang::Module *Module = 0;
1104 
1105   // If we don't already have information on this module, load the module now.
1106   llvm::DenseMap<const IdentifierInfo *, clang::Module *>::iterator Known
1107     = KnownModules.find(Path[0].first);
1108   if (Known != KnownModules.end()) {
1109     // Retrieve the cached top-level module.
1110     Module = Known->second;
1111   } else if (ModuleName == getLangOpts().CurrentModule) {
1112     // This is the module we're building.
1113     Module = PP->getHeaderSearchInfo().getModuleMap().findModule(ModuleName);
1114     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1115   } else {
1116     // Search for a module with the given name.
1117     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
1118     if (!Module) {
1119       getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_found)
1120       << ModuleName
1121       << SourceRange(ImportLoc, ModuleNameLoc);
1122       ModuleBuildFailed = true;
1123       return ModuleLoadResult();
1124     }
1125 
1126     std::string ModuleFileName = PP->getHeaderSearchInfo().getModuleFileName(Module);
1127 
1128     // If we don't already have an ASTReader, create one now.
1129     if (!ModuleManager) {
1130       if (!hasASTContext())
1131         createASTContext();
1132 
1133       // If we're not recursively building a module, check whether we
1134       // need to prune the module cache.
1135       if (getSourceManager().getModuleBuildStack().empty() &&
1136           getHeaderSearchOpts().ModuleCachePruneInterval > 0 &&
1137           getHeaderSearchOpts().ModuleCachePruneAfter > 0) {
1138         pruneModuleCache(getHeaderSearchOpts());
1139       }
1140 
1141       std::string Sysroot = getHeaderSearchOpts().Sysroot;
1142       const PreprocessorOptions &PPOpts = getPreprocessorOpts();
1143       ModuleManager = new ASTReader(getPreprocessor(), *Context,
1144                                     Sysroot.empty() ? "" : Sysroot.c_str(),
1145                                     PPOpts.DisablePCHValidation,
1146                                     /*AllowASTWithCompilerErrors=*/false,
1147                                     /*AllowConfigurationMismatch=*/false,
1148                                     /*ValidateSystemInputs=*/false,
1149                                     getFrontendOpts().UseGlobalModuleIndex);
1150       if (hasASTConsumer()) {
1151         ModuleManager->setDeserializationListener(
1152           getASTConsumer().GetASTDeserializationListener());
1153         getASTContext().setASTMutationListener(
1154           getASTConsumer().GetASTMutationListener());
1155       }
1156       getASTContext().setExternalSource(ModuleManager);
1157       if (hasSema())
1158         ModuleManager->InitializeSema(getSema());
1159       if (hasASTConsumer())
1160         ModuleManager->StartTranslationUnit(&getASTConsumer());
1161     }
1162 
1163     // Try to load the module file.
1164     unsigned ARRFlags = ASTReader::ARR_OutOfDate | ASTReader::ARR_Missing;
1165     switch (ModuleManager->ReadAST(ModuleFileName, serialization::MK_Module,
1166                                    ImportLoc, ARRFlags)) {
1167     case ASTReader::Success:
1168       break;
1169 
1170     case ASTReader::OutOfDate:
1171     case ASTReader::Missing: {
1172       // The module file is missing or out-of-date. Build it.
1173       assert(Module && "missing module file");
1174       // Check whether there is a cycle in the module graph.
1175       ModuleBuildStack ModPath = getSourceManager().getModuleBuildStack();
1176       ModuleBuildStack::iterator Pos = ModPath.begin(), PosEnd = ModPath.end();
1177       for (; Pos != PosEnd; ++Pos) {
1178         if (Pos->first == ModuleName)
1179           break;
1180       }
1181 
1182       if (Pos != PosEnd) {
1183         SmallString<256> CyclePath;
1184         for (; Pos != PosEnd; ++Pos) {
1185           CyclePath += Pos->first;
1186           CyclePath += " -> ";
1187         }
1188         CyclePath += ModuleName;
1189 
1190         getDiagnostics().Report(ModuleNameLoc, diag::err_module_cycle)
1191           << ModuleName << CyclePath;
1192         return ModuleLoadResult();
1193       }
1194 
1195       // Check whether we have already attempted to build this module (but
1196       // failed).
1197       if (getPreprocessorOpts().FailedModules &&
1198           getPreprocessorOpts().FailedModules->hasAlreadyFailed(ModuleName)) {
1199         getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_built)
1200           << ModuleName
1201           << SourceRange(ImportLoc, ModuleNameLoc);
1202         ModuleBuildFailed = true;
1203         return ModuleLoadResult();
1204       }
1205 
1206       // Try to compile the module.
1207       compileModule(*this, ModuleNameLoc, Module, ModuleFileName);
1208 
1209       // Try to read the module file, now that we've compiled it.
1210       ASTReader::ASTReadResult ReadResult
1211         = ModuleManager->ReadAST(ModuleFileName,
1212                                  serialization::MK_Module, ImportLoc,
1213                                  ASTReader::ARR_Missing);
1214       if (ReadResult != ASTReader::Success) {
1215         if (ReadResult == ASTReader::Missing) {
1216           getDiagnostics().Report(ModuleNameLoc,
1217                                   Module? diag::err_module_not_built
1218                                         : diag::err_module_not_found)
1219             << ModuleName
1220             << SourceRange(ImportLoc, ModuleNameLoc);
1221         }
1222 
1223         if (getPreprocessorOpts().FailedModules)
1224           getPreprocessorOpts().FailedModules->addFailed(ModuleName);
1225         KnownModules[Path[0].first] = 0;
1226         ModuleBuildFailed = true;
1227         return ModuleLoadResult();
1228       }
1229 
1230       // Okay, we've rebuilt and now loaded the module.
1231       break;
1232     }
1233 
1234     case ASTReader::VersionMismatch:
1235     case ASTReader::ConfigurationMismatch:
1236     case ASTReader::HadErrors:
1237       ModuleLoader::HadFatalFailure = true;
1238       // FIXME: The ASTReader will already have complained, but can we showhorn
1239       // that diagnostic information into a more useful form?
1240       KnownModules[Path[0].first] = 0;
1241       return ModuleLoadResult();
1242 
1243     case ASTReader::Failure:
1244       ModuleLoader::HadFatalFailure = true;
1245       // Already complained, but note now that we failed.
1246       KnownModules[Path[0].first] = 0;
1247       ModuleBuildFailed = true;
1248       return ModuleLoadResult();
1249     }
1250 
1251     // Cache the result of this top-level module lookup for later.
1252     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1253   }
1254 
1255   // If we never found the module, fail.
1256   if (!Module)
1257     return ModuleLoadResult();
1258 
1259   // Verify that the rest of the module path actually corresponds to
1260   // a submodule.
1261   if (Path.size() > 1) {
1262     for (unsigned I = 1, N = Path.size(); I != N; ++I) {
1263       StringRef Name = Path[I].first->getName();
1264       clang::Module *Sub = Module->findSubmodule(Name);
1265 
1266       if (!Sub) {
1267         // Attempt to perform typo correction to find a module name that works.
1268         SmallVector<StringRef, 2> Best;
1269         unsigned BestEditDistance = (std::numeric_limits<unsigned>::max)();
1270 
1271         for (clang::Module::submodule_iterator J = Module->submodule_begin(),
1272                                             JEnd = Module->submodule_end();
1273              J != JEnd; ++J) {
1274           unsigned ED = Name.edit_distance((*J)->Name,
1275                                            /*AllowReplacements=*/true,
1276                                            BestEditDistance);
1277           if (ED <= BestEditDistance) {
1278             if (ED < BestEditDistance) {
1279               Best.clear();
1280               BestEditDistance = ED;
1281             }
1282 
1283             Best.push_back((*J)->Name);
1284           }
1285         }
1286 
1287         // If there was a clear winner, user it.
1288         if (Best.size() == 1) {
1289           getDiagnostics().Report(Path[I].second,
1290                                   diag::err_no_submodule_suggest)
1291             << Path[I].first << Module->getFullModuleName() << Best[0]
1292             << SourceRange(Path[0].second, Path[I-1].second)
1293             << FixItHint::CreateReplacement(SourceRange(Path[I].second),
1294                                             Best[0]);
1295 
1296           Sub = Module->findSubmodule(Best[0]);
1297         }
1298       }
1299 
1300       if (!Sub) {
1301         // No submodule by this name. Complain, and don't look for further
1302         // submodules.
1303         getDiagnostics().Report(Path[I].second, diag::err_no_submodule)
1304           << Path[I].first << Module->getFullModuleName()
1305           << SourceRange(Path[0].second, Path[I-1].second);
1306         break;
1307       }
1308 
1309       Module = Sub;
1310     }
1311   }
1312 
1313   // Make the named module visible, if it's not already part of the module
1314   // we are parsing.
1315   if (ModuleName != getLangOpts().CurrentModule) {
1316     if (!Module->IsFromModuleFile) {
1317       // We have an umbrella header or directory that doesn't actually include
1318       // all of the headers within the directory it covers. Complain about
1319       // this missing submodule and recover by forgetting that we ever saw
1320       // this submodule.
1321       // FIXME: Should we detect this at module load time? It seems fairly
1322       // expensive (and rare).
1323       getDiagnostics().Report(ImportLoc, diag::warn_missing_submodule)
1324         << Module->getFullModuleName()
1325         << SourceRange(Path.front().second, Path.back().second);
1326 
1327       return ModuleLoadResult(0, true);
1328     }
1329 
1330     // Check whether this module is available.
1331     clang::Module::Requirement Requirement;
1332     clang::Module::HeaderDirective MissingHeader;
1333     if (!Module->isAvailable(getLangOpts(), getTarget(), Requirement,
1334                              MissingHeader)) {
1335       if (MissingHeader.FileNameLoc.isValid()) {
1336         getDiagnostics().Report(MissingHeader.FileNameLoc,
1337                                 diag::err_module_header_missing)
1338           << MissingHeader.IsUmbrella << MissingHeader.FileName;
1339       } else {
1340         getDiagnostics().Report(ImportLoc, diag::err_module_unavailable)
1341           << Module->getFullModuleName()
1342           << Requirement.second << Requirement.first
1343           << SourceRange(Path.front().second, Path.back().second);
1344       }
1345       LastModuleImportLoc = ImportLoc;
1346       LastModuleImportResult = ModuleLoadResult();
1347       return ModuleLoadResult();
1348     }
1349 
1350     ModuleManager->makeModuleVisible(Module, Visibility, ImportLoc,
1351                                      /*Complain=*/true);
1352   }
1353 
1354   // Check for any configuration macros that have changed.
1355   clang::Module *TopModule = Module->getTopLevelModule();
1356   for (unsigned I = 0, N = TopModule->ConfigMacros.size(); I != N; ++I) {
1357     checkConfigMacro(getPreprocessor(), TopModule->ConfigMacros[I],
1358                      Module, ImportLoc);
1359   }
1360 
1361   // If this module import was due to an inclusion directive, create an
1362   // implicit import declaration to capture it in the AST.
1363   if (IsInclusionDirective && hasASTContext()) {
1364     TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
1365     ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
1366                                                      ImportLoc, Module,
1367                                                      Path.back().second);
1368     TU->addDecl(ImportD);
1369     if (Consumer)
1370       Consumer->HandleImplicitImportDecl(ImportD);
1371   }
1372 
1373   LastModuleImportLoc = ImportLoc;
1374   LastModuleImportResult = ModuleLoadResult(Module, false);
1375   return LastModuleImportResult;
1376 }
1377 
1378 void CompilerInstance::makeModuleVisible(Module *Mod,
1379                                          Module::NameVisibilityKind Visibility,
1380                                          SourceLocation ImportLoc,
1381                                          bool Complain){
1382   ModuleManager->makeModuleVisible(Mod, Visibility, ImportLoc, Complain);
1383 }
1384 
1385