xref: /llvm-project/clang/lib/Frontend/CompilerInstance.cpp (revision 1d0912a475059c08018f4b18c055dc974d07451d)
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 }
83 
84 void CompilerInstance::setSourceManager(SourceManager *Value) {
85   SourceMgr = Value;
86 }
87 
88 void CompilerInstance::setPreprocessor(Preprocessor *Value) { PP = Value; }
89 
90 void CompilerInstance::setASTContext(ASTContext *Value) { Context = Value; }
91 
92 void CompilerInstance::setSema(Sema *S) {
93   TheSema.reset(S);
94 }
95 
96 void CompilerInstance::setASTConsumer(ASTConsumer *Value) {
97   Consumer.reset(Value);
98 }
99 
100 void CompilerInstance::setCodeCompletionConsumer(CodeCompleteConsumer *Value) {
101   CompletionConsumer.reset(Value);
102 }
103 
104 // Diagnostics
105 static void SetUpDiagnosticLog(DiagnosticOptions *DiagOpts,
106                                const CodeGenOptions *CodeGenOpts,
107                                DiagnosticsEngine &Diags) {
108   std::string ErrorInfo;
109   bool OwnsStream = false;
110   raw_ostream *OS = &llvm::errs();
111   if (DiagOpts->DiagnosticLogFile != "-") {
112     // Create the output stream.
113     llvm::raw_fd_ostream *FileOS(
114       new llvm::raw_fd_ostream(DiagOpts->DiagnosticLogFile.c_str(),
115                                ErrorInfo, llvm::raw_fd_ostream::F_Append));
116     if (!ErrorInfo.empty()) {
117       Diags.Report(diag::warn_fe_cc_log_diagnostics_failure)
118         << DiagOpts->DiagnosticLogFile << ErrorInfo;
119     } else {
120       FileOS->SetUnbuffered();
121       FileOS->SetUseAtomicWrites(true);
122       OS = FileOS;
123       OwnsStream = true;
124     }
125   }
126 
127   // Chain in the diagnostic client which will log the diagnostics.
128   LogDiagnosticPrinter *Logger = new LogDiagnosticPrinter(*OS, DiagOpts,
129                                                           OwnsStream);
130   if (CodeGenOpts)
131     Logger->setDwarfDebugFlags(CodeGenOpts->DwarfDebugFlags);
132   Diags.setClient(new ChainedDiagnosticConsumer(Diags.takeClient(), Logger));
133 }
134 
135 static void SetupSerializedDiagnostics(DiagnosticOptions *DiagOpts,
136                                        DiagnosticsEngine &Diags,
137                                        StringRef OutputFile) {
138   std::string ErrorInfo;
139   OwningPtr<llvm::raw_fd_ostream> OS;
140   OS.reset(new llvm::raw_fd_ostream(OutputFile.str().c_str(), ErrorInfo,
141                                     llvm::raw_fd_ostream::F_Binary));
142 
143   if (!ErrorInfo.empty()) {
144     Diags.Report(diag::warn_fe_serialized_diag_failure)
145       << OutputFile << ErrorInfo;
146     return;
147   }
148 
149   DiagnosticConsumer *SerializedConsumer =
150     clang::serialized_diags::create(OS.take(), DiagOpts);
151 
152 
153   Diags.setClient(new ChainedDiagnosticConsumer(Diags.takeClient(),
154                                                 SerializedConsumer));
155 }
156 
157 void CompilerInstance::createDiagnostics(DiagnosticConsumer *Client,
158                                          bool ShouldOwnClient) {
159   Diagnostics = createDiagnostics(&getDiagnosticOpts(), Client,
160                                   ShouldOwnClient, &getCodeGenOpts());
161 }
162 
163 IntrusiveRefCntPtr<DiagnosticsEngine>
164 CompilerInstance::createDiagnostics(DiagnosticOptions *Opts,
165                                     DiagnosticConsumer *Client,
166                                     bool ShouldOwnClient,
167                                     const CodeGenOptions *CodeGenOpts) {
168   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
169   IntrusiveRefCntPtr<DiagnosticsEngine>
170       Diags(new DiagnosticsEngine(DiagID, Opts));
171 
172   // Create the diagnostic client for reporting errors or for
173   // implementing -verify.
174   if (Client) {
175     Diags->setClient(Client, ShouldOwnClient);
176   } else
177     Diags->setClient(new TextDiagnosticPrinter(llvm::errs(), Opts));
178 
179   // Chain in -verify checker, if requested.
180   if (Opts->VerifyDiagnostics)
181     Diags->setClient(new VerifyDiagnosticConsumer(*Diags));
182 
183   // Chain in -diagnostic-log-file dumper, if requested.
184   if (!Opts->DiagnosticLogFile.empty())
185     SetUpDiagnosticLog(Opts, CodeGenOpts, *Diags);
186 
187   if (!Opts->DiagnosticSerializationFile.empty())
188     SetupSerializedDiagnostics(Opts, *Diags,
189                                Opts->DiagnosticSerializationFile);
190 
191   // Configure our handling of diagnostics.
192   ProcessWarningOptions(*Diags, *Opts);
193 
194   return Diags;
195 }
196 
197 // File Manager
198 
199 void CompilerInstance::createFileManager() {
200   FileMgr = new FileManager(getFileSystemOpts());
201 }
202 
203 // Source Manager
204 
205 void CompilerInstance::createSourceManager(FileManager &FileMgr) {
206   SourceMgr = new SourceManager(getDiagnostics(), FileMgr);
207 }
208 
209 // Preprocessor
210 
211 void CompilerInstance::createPreprocessor() {
212   const PreprocessorOptions &PPOpts = getPreprocessorOpts();
213 
214   // Create a PTH manager if we are using some form of a token cache.
215   PTHManager *PTHMgr = 0;
216   if (!PPOpts.TokenCache.empty())
217     PTHMgr = PTHManager::Create(PPOpts.TokenCache, getDiagnostics());
218 
219   // Create the Preprocessor.
220   HeaderSearch *HeaderInfo = new HeaderSearch(&getHeaderSearchOpts(),
221                                               getFileManager(),
222                                               getDiagnostics(),
223                                               getLangOpts(),
224                                               &getTarget());
225   PP = new Preprocessor(&getPreprocessorOpts(),
226                         getDiagnostics(), getLangOpts(), &getTarget(),
227                         getSourceManager(), *HeaderInfo, *this, PTHMgr,
228                         /*OwnsHeaderSearch=*/true);
229 
230   // Note that this is different then passing PTHMgr to Preprocessor's ctor.
231   // That argument is used as the IdentifierInfoLookup argument to
232   // IdentifierTable's ctor.
233   if (PTHMgr) {
234     PTHMgr->setPreprocessor(&*PP);
235     PP->setPTHManager(PTHMgr);
236   }
237 
238   if (PPOpts.DetailedRecord)
239     PP->createPreprocessingRecord();
240 
241   InitializePreprocessor(*PP, PPOpts, getHeaderSearchOpts(), getFrontendOpts());
242 
243   PP->setPreprocessedOutput(getPreprocessorOutputOpts().ShowCPP);
244 
245   // Set up the module path, including the hash for the
246   // module-creation options.
247   SmallString<256> SpecificModuleCache(
248                            getHeaderSearchOpts().ModuleCachePath);
249   if (!getHeaderSearchOpts().DisableModuleHash)
250     llvm::sys::path::append(SpecificModuleCache,
251                             getInvocation().getModuleHash());
252   PP->getHeaderSearchInfo().setModuleCachePath(SpecificModuleCache);
253 
254   // Handle generating dependencies, if requested.
255   const DependencyOutputOptions &DepOpts = getDependencyOutputOpts();
256   if (!DepOpts.OutputFile.empty())
257     AttachDependencyFileGen(*PP, DepOpts);
258   if (!DepOpts.DOTOutputFile.empty())
259     AttachDependencyGraphGen(*PP, DepOpts.DOTOutputFile,
260                              getHeaderSearchOpts().Sysroot);
261 
262 
263   // Handle generating header include information, if requested.
264   if (DepOpts.ShowHeaderIncludes)
265     AttachHeaderIncludeGen(*PP);
266   if (!DepOpts.HeaderIncludeOutputFile.empty()) {
267     StringRef OutputPath = DepOpts.HeaderIncludeOutputFile;
268     if (OutputPath == "-")
269       OutputPath = "";
270     AttachHeaderIncludeGen(*PP, /*ShowAllHeaders=*/true, OutputPath,
271                            /*ShowDepth=*/false);
272   }
273 }
274 
275 // ASTContext
276 
277 void CompilerInstance::createASTContext() {
278   Preprocessor &PP = getPreprocessor();
279   Context = new ASTContext(getLangOpts(), PP.getSourceManager(),
280                            &getTarget(), PP.getIdentifierTable(),
281                            PP.getSelectorTable(), PP.getBuiltinInfo(),
282                            /*size_reserve=*/ 0);
283 }
284 
285 // ExternalASTSource
286 
287 void CompilerInstance::createPCHExternalASTSource(StringRef Path,
288                                                   bool DisablePCHValidation,
289                                                 bool AllowPCHWithCompilerErrors,
290                                                  void *DeserializationListener){
291   OwningPtr<ExternalASTSource> Source;
292   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
293   Source.reset(createPCHExternalASTSource(Path, getHeaderSearchOpts().Sysroot,
294                                           DisablePCHValidation,
295                                           AllowPCHWithCompilerErrors,
296                                           getPreprocessor(), getASTContext(),
297                                           DeserializationListener,
298                                           Preamble,
299                                        getFrontendOpts().UseGlobalModuleIndex));
300   ModuleManager = static_cast<ASTReader*>(Source.get());
301   getASTContext().setExternalSource(Source);
302 }
303 
304 ExternalASTSource *
305 CompilerInstance::createPCHExternalASTSource(StringRef Path,
306                                              const std::string &Sysroot,
307                                              bool DisablePCHValidation,
308                                              bool AllowPCHWithCompilerErrors,
309                                              Preprocessor &PP,
310                                              ASTContext &Context,
311                                              void *DeserializationListener,
312                                              bool Preamble,
313                                              bool UseGlobalModuleIndex) {
314   OwningPtr<ASTReader> Reader;
315   Reader.reset(new ASTReader(PP, Context,
316                              Sysroot.empty() ? "" : Sysroot.c_str(),
317                              DisablePCHValidation,
318                              AllowPCHWithCompilerErrors,
319                              UseGlobalModuleIndex));
320 
321   Reader->setDeserializationListener(
322             static_cast<ASTDeserializationListener *>(DeserializationListener));
323   switch (Reader->ReadAST(Path,
324                           Preamble ? serialization::MK_Preamble
325                                    : serialization::MK_PCH,
326                           SourceLocation(),
327                           ASTReader::ARR_None)) {
328   case ASTReader::Success:
329     // Set the predefines buffer as suggested by the PCH reader. Typically, the
330     // predefines buffer will be empty.
331     PP.setPredefines(Reader->getSuggestedPredefines());
332     return Reader.take();
333 
334   case ASTReader::Failure:
335     // Unrecoverable failure: don't even try to process the input file.
336     break;
337 
338   case ASTReader::Missing:
339   case ASTReader::OutOfDate:
340   case ASTReader::VersionMismatch:
341   case ASTReader::ConfigurationMismatch:
342   case ASTReader::HadErrors:
343     // No suitable PCH file could be found. Return an error.
344     break;
345   }
346 
347   return 0;
348 }
349 
350 // Code Completion
351 
352 static bool EnableCodeCompletion(Preprocessor &PP,
353                                  const std::string &Filename,
354                                  unsigned Line,
355                                  unsigned Column) {
356   // Tell the source manager to chop off the given file at a specific
357   // line and column.
358   const FileEntry *Entry = PP.getFileManager().getFile(Filename);
359   if (!Entry) {
360     PP.getDiagnostics().Report(diag::err_fe_invalid_code_complete_file)
361       << Filename;
362     return true;
363   }
364 
365   // Truncate the named file at the given line/column.
366   PP.SetCodeCompletionPoint(Entry, Line, Column);
367   return false;
368 }
369 
370 void CompilerInstance::createCodeCompletionConsumer() {
371   const ParsedSourceLocation &Loc = getFrontendOpts().CodeCompletionAt;
372   if (!CompletionConsumer) {
373     setCodeCompletionConsumer(
374       createCodeCompletionConsumer(getPreprocessor(),
375                                    Loc.FileName, Loc.Line, Loc.Column,
376                                    getFrontendOpts().CodeCompleteOpts,
377                                    llvm::outs()));
378     if (!CompletionConsumer)
379       return;
380   } else if (EnableCodeCompletion(getPreprocessor(), Loc.FileName,
381                                   Loc.Line, Loc.Column)) {
382     setCodeCompletionConsumer(0);
383     return;
384   }
385 
386   if (CompletionConsumer->isOutputBinary() &&
387       llvm::sys::ChangeStdoutToBinary()) {
388     getPreprocessor().getDiagnostics().Report(diag::err_fe_stdout_binary);
389     setCodeCompletionConsumer(0);
390   }
391 }
392 
393 void CompilerInstance::createFrontendTimer() {
394   FrontendTimer.reset(new llvm::Timer("Clang front-end timer"));
395 }
396 
397 CodeCompleteConsumer *
398 CompilerInstance::createCodeCompletionConsumer(Preprocessor &PP,
399                                                const std::string &Filename,
400                                                unsigned Line,
401                                                unsigned Column,
402                                                const CodeCompleteOptions &Opts,
403                                                raw_ostream &OS) {
404   if (EnableCodeCompletion(PP, Filename, Line, Column))
405     return 0;
406 
407   // Set up the creation routine for code-completion.
408   return new PrintingCodeCompleteConsumer(Opts, OS);
409 }
410 
411 void CompilerInstance::createSema(TranslationUnitKind TUKind,
412                                   CodeCompleteConsumer *CompletionConsumer) {
413   TheSema.reset(new Sema(getPreprocessor(), getASTContext(), getASTConsumer(),
414                          TUKind, CompletionConsumer));
415 }
416 
417 // Output Files
418 
419 void CompilerInstance::addOutputFile(const OutputFile &OutFile) {
420   assert(OutFile.OS && "Attempt to add empty stream to output list!");
421   OutputFiles.push_back(OutFile);
422 }
423 
424 void CompilerInstance::clearOutputFiles(bool EraseFiles) {
425   for (std::list<OutputFile>::iterator
426          it = OutputFiles.begin(), ie = OutputFiles.end(); it != ie; ++it) {
427     delete it->OS;
428     if (!it->TempFilename.empty()) {
429       if (EraseFiles) {
430         bool existed;
431         llvm::sys::fs::remove(it->TempFilename, existed);
432       } else {
433         SmallString<128> NewOutFile(it->Filename);
434 
435         // If '-working-directory' was passed, the output filename should be
436         // relative to that.
437         FileMgr->FixupRelativePath(NewOutFile);
438         if (llvm::error_code ec = llvm::sys::fs::rename(it->TempFilename,
439                                                         NewOutFile.str())) {
440           getDiagnostics().Report(diag::err_unable_to_rename_temp)
441             << it->TempFilename << it->Filename << ec.message();
442 
443           bool existed;
444           llvm::sys::fs::remove(it->TempFilename, existed);
445         }
446       }
447     } else if (!it->Filename.empty() && EraseFiles)
448       llvm::sys::fs::remove(it->Filename);
449 
450   }
451   OutputFiles.clear();
452 }
453 
454 llvm::raw_fd_ostream *
455 CompilerInstance::createDefaultOutputFile(bool Binary,
456                                           StringRef InFile,
457                                           StringRef Extension) {
458   return createOutputFile(getFrontendOpts().OutputFile, Binary,
459                           /*RemoveFileOnSignal=*/true, InFile, Extension,
460                           /*UseTemporary=*/true);
461 }
462 
463 llvm::raw_fd_ostream *
464 CompilerInstance::createOutputFile(StringRef OutputPath,
465                                    bool Binary, bool RemoveFileOnSignal,
466                                    StringRef InFile,
467                                    StringRef Extension,
468                                    bool UseTemporary,
469                                    bool CreateMissingDirectories) {
470   std::string Error, OutputPathName, TempPathName;
471   llvm::raw_fd_ostream *OS = createOutputFile(OutputPath, Error, Binary,
472                                               RemoveFileOnSignal,
473                                               InFile, Extension,
474                                               UseTemporary,
475                                               CreateMissingDirectories,
476                                               &OutputPathName,
477                                               &TempPathName);
478   if (!OS) {
479     getDiagnostics().Report(diag::err_fe_unable_to_open_output)
480       << OutputPath << Error;
481     return 0;
482   }
483 
484   // Add the output file -- but don't try to remove "-", since this means we are
485   // using stdin.
486   addOutputFile(OutputFile((OutputPathName != "-") ? OutputPathName : "",
487                 TempPathName, OS));
488 
489   return OS;
490 }
491 
492 llvm::raw_fd_ostream *
493 CompilerInstance::createOutputFile(StringRef OutputPath,
494                                    std::string &Error,
495                                    bool Binary,
496                                    bool RemoveFileOnSignal,
497                                    StringRef InFile,
498                                    StringRef Extension,
499                                    bool UseTemporary,
500                                    bool CreateMissingDirectories,
501                                    std::string *ResultPathName,
502                                    std::string *TempPathName) {
503   assert((!CreateMissingDirectories || UseTemporary) &&
504          "CreateMissingDirectories is only allowed when using temporary files");
505 
506   std::string OutFile, TempFile;
507   if (!OutputPath.empty()) {
508     OutFile = OutputPath;
509   } else if (InFile == "-") {
510     OutFile = "-";
511   } else if (!Extension.empty()) {
512     SmallString<128> Path(InFile);
513     llvm::sys::path::replace_extension(Path, Extension);
514     OutFile = Path.str();
515   } else {
516     OutFile = "-";
517   }
518 
519   OwningPtr<llvm::raw_fd_ostream> OS;
520   std::string OSFile;
521 
522   if (UseTemporary) {
523     if (OutFile == "-")
524       UseTemporary = false;
525     else {
526       llvm::sys::fs::file_status Status;
527       llvm::sys::fs::status(OutputPath, Status);
528       if (llvm::sys::fs::exists(Status)) {
529         // Fail early if we can't write to the final destination.
530         if (!llvm::sys::fs::can_write(OutputPath))
531           return 0;
532 
533         // Don't use a temporary if the output is a special file. This handles
534         // things like '-o /dev/null'
535         if (!llvm::sys::fs::is_regular_file(Status))
536           UseTemporary = false;
537       }
538     }
539   }
540 
541   if (UseTemporary) {
542     // Create a temporary file.
543     SmallString<128> TempPath;
544     TempPath = OutFile;
545     TempPath += "-%%%%%%%%";
546     int fd;
547     llvm::error_code EC = llvm::sys::fs::unique_file(
548         TempPath.str(), fd, TempPath, /*makeAbsolute=*/ false, 0664);
549 
550     if (CreateMissingDirectories &&
551         EC == llvm::errc::no_such_file_or_directory) {
552       StringRef Parent = llvm::sys::path::parent_path(OutputPath);
553       EC = llvm::sys::fs::create_directories(Parent);
554       if (!EC) {
555         EC = llvm::sys::fs::unique_file(TempPath.str(), fd, TempPath,
556                                         /*makeAbsolute=*/ false, 0664);
557       }
558     }
559 
560     if (!EC) {
561       OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
562       OSFile = TempFile = TempPath.str();
563     }
564     // If we failed to create the temporary, fallback to writing to the file
565     // directly. This handles the corner case where we cannot write to the
566     // directory, but can write to the file.
567   }
568 
569   if (!OS) {
570     OSFile = OutFile;
571     OS.reset(
572       new llvm::raw_fd_ostream(OSFile.c_str(), Error,
573                                (Binary ? llvm::raw_fd_ostream::F_Binary : 0)));
574     if (!Error.empty())
575       return 0;
576   }
577 
578   // Make sure the out stream file gets removed if we crash.
579   if (RemoveFileOnSignal)
580     llvm::sys::RemoveFileOnSignal(OSFile);
581 
582   if (ResultPathName)
583     *ResultPathName = OutFile;
584   if (TempPathName)
585     *TempPathName = TempFile;
586 
587   return OS.take();
588 }
589 
590 // Initialization Utilities
591 
592 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input){
593   return InitializeSourceManager(Input, getDiagnostics(),
594                                  getFileManager(), getSourceManager(),
595                                  getFrontendOpts());
596 }
597 
598 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input,
599                                                DiagnosticsEngine &Diags,
600                                                FileManager &FileMgr,
601                                                SourceManager &SourceMgr,
602                                                const FrontendOptions &Opts) {
603   SrcMgr::CharacteristicKind
604     Kind = Input.isSystem() ? SrcMgr::C_System : SrcMgr::C_User;
605 
606   if (Input.isBuffer()) {
607     SourceMgr.createMainFileIDForMemBuffer(Input.getBuffer(), Kind);
608     assert(!SourceMgr.getMainFileID().isInvalid() &&
609            "Couldn't establish MainFileID!");
610     return true;
611   }
612 
613   StringRef InputFile = Input.getFile();
614 
615   // Figure out where to get and map in the main file.
616   if (InputFile != "-") {
617     const FileEntry *File = FileMgr.getFile(InputFile);
618     if (!File) {
619       Diags.Report(diag::err_fe_error_reading) << InputFile;
620       return false;
621     }
622 
623     // The natural SourceManager infrastructure can't currently handle named
624     // pipes, but we would at least like to accept them for the main
625     // file. Detect them here, read them with the more generic MemoryBuffer
626     // function, and simply override their contents as we do for STDIN.
627     if (File->isNamedPipe()) {
628       OwningPtr<llvm::MemoryBuffer> MB;
629       if (llvm::error_code ec = llvm::MemoryBuffer::getFile(InputFile, MB)) {
630         Diags.Report(diag::err_cannot_open_file) << InputFile << ec.message();
631         return false;
632       }
633 
634       // Create a new virtual file that will have the correct size.
635       File = FileMgr.getVirtualFile(InputFile, MB->getBufferSize(), 0);
636       SourceMgr.overrideFileContents(File, MB.take());
637     }
638 
639     SourceMgr.createMainFileID(File, Kind);
640   } else {
641     OwningPtr<llvm::MemoryBuffer> SB;
642     if (llvm::MemoryBuffer::getSTDIN(SB)) {
643       // FIXME: Give ec.message() in this diag.
644       Diags.Report(diag::err_fe_error_reading_stdin);
645       return false;
646     }
647     const FileEntry *File = FileMgr.getVirtualFile(SB->getBufferIdentifier(),
648                                                    SB->getBufferSize(), 0);
649     SourceMgr.createMainFileID(File, Kind);
650     SourceMgr.overrideFileContents(File, SB.take());
651   }
652 
653   assert(!SourceMgr.getMainFileID().isInvalid() &&
654          "Couldn't establish MainFileID!");
655   return true;
656 }
657 
658 // High-Level Operations
659 
660 bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
661   assert(hasDiagnostics() && "Diagnostics engine is not initialized!");
662   assert(!getFrontendOpts().ShowHelp && "Client must handle '-help'!");
663   assert(!getFrontendOpts().ShowVersion && "Client must handle '-version'!");
664 
665   // FIXME: Take this as an argument, once all the APIs we used have moved to
666   // taking it as an input instead of hard-coding llvm::errs.
667   raw_ostream &OS = llvm::errs();
668 
669   // Create the target instance.
670   setTarget(TargetInfo::CreateTargetInfo(getDiagnostics(), &getTargetOpts()));
671   if (!hasTarget())
672     return false;
673 
674   // Inform the target of the language options.
675   //
676   // FIXME: We shouldn't need to do this, the target should be immutable once
677   // created. This complexity should be lifted elsewhere.
678   getTarget().setForcedLangOptions(getLangOpts());
679 
680   // rewriter project will change target built-in bool type from its default.
681   if (getFrontendOpts().ProgramAction == frontend::RewriteObjC)
682     getTarget().noSignedCharForObjCBool();
683 
684   // Validate/process some options.
685   if (getHeaderSearchOpts().Verbose)
686     OS << "clang -cc1 version " CLANG_VERSION_STRING
687        << " based upon " << PACKAGE_STRING
688        << " default target " << llvm::sys::getDefaultTargetTriple() << "\n";
689 
690   if (getFrontendOpts().ShowTimers)
691     createFrontendTimer();
692 
693   if (getFrontendOpts().ShowStats)
694     llvm::EnableStatistics();
695 
696   for (unsigned i = 0, e = getFrontendOpts().Inputs.size(); i != e; ++i) {
697     // Reset the ID tables if we are reusing the SourceManager.
698     if (hasSourceManager())
699       getSourceManager().clearIDTables();
700 
701     if (Act.BeginSourceFile(*this, getFrontendOpts().Inputs[i])) {
702       Act.Execute();
703       Act.EndSourceFile();
704     }
705   }
706 
707   // Notify the diagnostic client that all files were processed.
708   getDiagnostics().getClient()->finish();
709 
710   if (getDiagnosticOpts().ShowCarets) {
711     // We can have multiple diagnostics sharing one diagnostic client.
712     // Get the total number of warnings/errors from the client.
713     unsigned NumWarnings = getDiagnostics().getClient()->getNumWarnings();
714     unsigned NumErrors = getDiagnostics().getClient()->getNumErrors();
715 
716     if (NumWarnings)
717       OS << NumWarnings << " warning" << (NumWarnings == 1 ? "" : "s");
718     if (NumWarnings && NumErrors)
719       OS << " and ";
720     if (NumErrors)
721       OS << NumErrors << " error" << (NumErrors == 1 ? "" : "s");
722     if (NumWarnings || NumErrors)
723       OS << " generated.\n";
724   }
725 
726   if (getFrontendOpts().ShowStats && hasFileManager()) {
727     getFileManager().PrintStats();
728     OS << "\n";
729   }
730 
731   return !getDiagnostics().getClient()->getNumErrors();
732 }
733 
734 /// \brief Determine the appropriate source input kind based on language
735 /// options.
736 static InputKind getSourceInputKindFromOptions(const LangOptions &LangOpts) {
737   if (LangOpts.OpenCL)
738     return IK_OpenCL;
739   if (LangOpts.CUDA)
740     return IK_CUDA;
741   if (LangOpts.ObjC1)
742     return LangOpts.CPlusPlus? IK_ObjCXX : IK_ObjC;
743   return LangOpts.CPlusPlus? IK_CXX : IK_C;
744 }
745 
746 namespace {
747   struct CompileModuleMapData {
748     CompilerInstance &Instance;
749     GenerateModuleAction &CreateModuleAction;
750   };
751 }
752 
753 /// \brief Helper function that executes the module-generating action under
754 /// a crash recovery context.
755 static void doCompileMapModule(void *UserData) {
756   CompileModuleMapData &Data
757     = *reinterpret_cast<CompileModuleMapData *>(UserData);
758   Data.Instance.ExecuteAction(Data.CreateModuleAction);
759 }
760 
761 namespace {
762   /// \brief Function object that checks with the given macro definition should
763   /// be removed, because it is one of the ignored macros.
764   class RemoveIgnoredMacro {
765     const HeaderSearchOptions &HSOpts;
766 
767   public:
768     explicit RemoveIgnoredMacro(const HeaderSearchOptions &HSOpts)
769       : HSOpts(HSOpts) { }
770 
771     bool operator()(const std::pair<std::string, bool> &def) const {
772       StringRef MacroDef = def.first;
773       return HSOpts.ModulesIgnoreMacros.count(MacroDef.split('=').first) > 0;
774     }
775   };
776 }
777 
778 /// \brief Compile a module file for the given module, using the options
779 /// provided by the importing compiler instance.
780 static void compileModule(CompilerInstance &ImportingInstance,
781                           SourceLocation ImportLoc,
782                           Module *Module,
783                           StringRef ModuleFileName) {
784   // FIXME: have LockFileManager return an error_code so that we can
785   // avoid the mkdir when the directory already exists.
786   StringRef Dir = llvm::sys::path::parent_path(ModuleFileName);
787   llvm::sys::fs::create_directories(Dir);
788 
789   llvm::LockFileManager Locked(ModuleFileName);
790   switch (Locked) {
791   case llvm::LockFileManager::LFS_Error:
792     return;
793 
794   case llvm::LockFileManager::LFS_Owned:
795     // We're responsible for building the module ourselves. Do so below.
796     break;
797 
798   case llvm::LockFileManager::LFS_Shared:
799     // Someone else is responsible for building the module. Wait for them to
800     // finish.
801     Locked.waitForUnlock();
802     return;
803   }
804 
805   ModuleMap &ModMap
806     = ImportingInstance.getPreprocessor().getHeaderSearchInfo().getModuleMap();
807 
808   // Construct a compiler invocation for creating this module.
809   IntrusiveRefCntPtr<CompilerInvocation> Invocation
810     (new CompilerInvocation(ImportingInstance.getInvocation()));
811 
812   PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
813 
814   // For any options that aren't intended to affect how a module is built,
815   // reset them to their default values.
816   Invocation->getLangOpts()->resetNonModularOptions();
817   PPOpts.resetNonModularOptions();
818 
819   // Remove any macro definitions that are explicitly ignored by the module.
820   // They aren't supposed to affect how the module is built anyway.
821   const HeaderSearchOptions &HSOpts = Invocation->getHeaderSearchOpts();
822   PPOpts.Macros.erase(std::remove_if(PPOpts.Macros.begin(), PPOpts.Macros.end(),
823                                      RemoveIgnoredMacro(HSOpts)),
824                       PPOpts.Macros.end());
825 
826 
827   // Note the name of the module we're building.
828   Invocation->getLangOpts()->CurrentModule = Module->getTopLevelModuleName();
829 
830   // Make sure that the failed-module structure has been allocated in
831   // the importing instance, and propagate the pointer to the newly-created
832   // instance.
833   PreprocessorOptions &ImportingPPOpts
834     = ImportingInstance.getInvocation().getPreprocessorOpts();
835   if (!ImportingPPOpts.FailedModules)
836     ImportingPPOpts.FailedModules = new PreprocessorOptions::FailedModulesSet;
837   PPOpts.FailedModules = ImportingPPOpts.FailedModules;
838 
839   // If there is a module map file, build the module using the module map.
840   // Set up the inputs/outputs so that we build the module from its umbrella
841   // header.
842   FrontendOptions &FrontendOpts = Invocation->getFrontendOpts();
843   FrontendOpts.OutputFile = ModuleFileName.str();
844   FrontendOpts.DisableFree = false;
845   FrontendOpts.GenerateGlobalModuleIndex = false;
846   FrontendOpts.Inputs.clear();
847   InputKind IK = getSourceInputKindFromOptions(*Invocation->getLangOpts());
848 
849   // Get or create the module map that we'll use to build this module.
850   SmallString<128> TempModuleMapFileName;
851   if (const FileEntry *ModuleMapFile
852                                   = ModMap.getContainingModuleMapFile(Module)) {
853     // Use the module map where this module resides.
854     FrontendOpts.Inputs.push_back(FrontendInputFile(ModuleMapFile->getName(),
855                                                     IK));
856   } else {
857     // Create a temporary module map file.
858     TempModuleMapFileName = Module->Name;
859     TempModuleMapFileName += "-%%%%%%%%.map";
860     int FD;
861     if (llvm::sys::fs::unique_file(TempModuleMapFileName.str(), FD,
862                                    TempModuleMapFileName,
863                                    /*makeAbsolute=*/true)
864           != llvm::errc::success) {
865       ImportingInstance.getDiagnostics().Report(diag::err_module_map_temp_file)
866         << TempModuleMapFileName;
867       return;
868     }
869     // Print the module map to this file.
870     llvm::raw_fd_ostream OS(FD, /*shouldClose=*/true);
871     Module->print(OS);
872     FrontendOpts.Inputs.push_back(
873       FrontendInputFile(TempModuleMapFileName.str().str(), IK));
874   }
875 
876   // Don't free the remapped file buffers; they are owned by our caller.
877   PPOpts.RetainRemappedFileBuffers = true;
878 
879   Invocation->getDiagnosticOpts().VerifyDiagnostics = 0;
880   assert(ImportingInstance.getInvocation().getModuleHash() ==
881          Invocation->getModuleHash() && "Module hash mismatch!");
882 
883   // Construct a compiler instance that will be used to actually create the
884   // module.
885   CompilerInstance Instance;
886   Instance.setInvocation(&*Invocation);
887 
888   Instance.createDiagnostics(new ForwardingDiagnosticConsumer(
889                                    ImportingInstance.getDiagnosticClient()),
890                              /*ShouldOwnClient=*/true);
891 
892   // Note that this module is part of the module build stack, so that we
893   // can detect cycles in the module graph.
894   Instance.createFileManager(); // FIXME: Adopt file manager from importer?
895   Instance.createSourceManager(Instance.getFileManager());
896   SourceManager &SourceMgr = Instance.getSourceManager();
897   SourceMgr.setModuleBuildStack(
898     ImportingInstance.getSourceManager().getModuleBuildStack());
899   SourceMgr.pushModuleBuildStack(Module->getTopLevelModuleName(),
900     FullSourceLoc(ImportLoc, ImportingInstance.getSourceManager()));
901 
902 
903   // Construct a module-generating action.
904   GenerateModuleAction CreateModuleAction(Module->IsSystem);
905 
906   // Execute the action to actually build the module in-place. Use a separate
907   // thread so that we get a stack large enough.
908   const unsigned ThreadStackSize = 8 << 20;
909   llvm::CrashRecoveryContext CRC;
910   CompileModuleMapData Data = { Instance, CreateModuleAction };
911   CRC.RunSafelyOnThread(&doCompileMapModule, &Data, ThreadStackSize);
912 
913 
914   // Delete the temporary module map file.
915   // FIXME: Even though we're executing under crash protection, it would still
916   // be nice to do this with RemoveFileOnSignal when we can. However, that
917   // doesn't make sense for all clients, so clean this up manually.
918   Instance.clearOutputFiles(/*EraseFiles=*/true);
919   if (!TempModuleMapFileName.empty())
920     llvm::sys::fs::remove(TempModuleMapFileName.str());
921 
922   // We've rebuilt a module. If we're allowed to generate or update the global
923   // module index, record that fact in the importing compiler instance.
924   if (ImportingInstance.getFrontendOpts().GenerateGlobalModuleIndex) {
925     ImportingInstance.setBuildGlobalModuleIndex(true);
926   }
927 }
928 
929 /// \brief Diagnose differences between the current definition of the given
930 /// configuration macro and the definition provided on the command line.
931 static void checkConfigMacro(Preprocessor &PP, StringRef ConfigMacro,
932                              Module *Mod, SourceLocation ImportLoc) {
933   IdentifierInfo *Id = PP.getIdentifierInfo(ConfigMacro);
934   SourceManager &SourceMgr = PP.getSourceManager();
935 
936   // If this identifier has never had a macro definition, then it could
937   // not have changed.
938   if (!Id->hadMacroDefinition())
939     return;
940 
941   // If this identifier does not currently have a macro definition,
942   // check whether it had one on the command line.
943   if (!Id->hasMacroDefinition()) {
944     MacroDirective::DefInfo LatestDef =
945         PP.getMacroDirectiveHistory(Id)->getDefinition();
946     for (MacroDirective::DefInfo Def = LatestDef; Def;
947            Def = Def.getPreviousDefinition()) {
948       FileID FID = SourceMgr.getFileID(Def.getLocation());
949       if (FID.isInvalid())
950         continue;
951 
952       // We only care about the predefines buffer.
953       if (FID != PP.getPredefinesFileID())
954         continue;
955 
956       // This macro was defined on the command line, then #undef'd later.
957       // Complain.
958       PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
959         << true << ConfigMacro << Mod->getFullModuleName();
960       if (LatestDef.isUndefined())
961         PP.Diag(LatestDef.getUndefLocation(), diag::note_module_def_undef_here)
962           << true;
963       return;
964     }
965 
966     // Okay: no definition in the predefines buffer.
967     return;
968   }
969 
970   // This identifier has a macro definition. Check whether we had a definition
971   // on the command line.
972   MacroDirective::DefInfo LatestDef =
973       PP.getMacroDirectiveHistory(Id)->getDefinition();
974   MacroDirective::DefInfo PredefinedDef;
975   for (MacroDirective::DefInfo Def = LatestDef; Def;
976          Def = Def.getPreviousDefinition()) {
977     FileID FID = SourceMgr.getFileID(Def.getLocation());
978     if (FID.isInvalid())
979       continue;
980 
981     // We only care about the predefines buffer.
982     if (FID != PP.getPredefinesFileID())
983       continue;
984 
985     PredefinedDef = Def;
986     break;
987   }
988 
989   // If there was no definition for this macro in the predefines buffer,
990   // complain.
991   if (!PredefinedDef ||
992       (!PredefinedDef.getLocation().isValid() &&
993        PredefinedDef.getUndefLocation().isValid())) {
994     PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
995       << false << ConfigMacro << Mod->getFullModuleName();
996     PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
997       << false;
998     return;
999   }
1000 
1001   // If the current macro definition is the same as the predefined macro
1002   // definition, it's okay.
1003   if (LatestDef.getMacroInfo() == PredefinedDef.getMacroInfo() ||
1004       LatestDef.getMacroInfo()->isIdenticalTo(*PredefinedDef.getMacroInfo(),PP,
1005                                               /*Syntactically=*/true))
1006     return;
1007 
1008   // The macro definitions differ.
1009   PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
1010     << false << ConfigMacro << Mod->getFullModuleName();
1011   PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
1012     << false;
1013 }
1014 
1015 /// \brief Write a new timestamp file with the given path.
1016 static void writeTimestampFile(StringRef TimestampFile) {
1017   std::string ErrorInfo;
1018   llvm::raw_fd_ostream Out(TimestampFile.str().c_str(), ErrorInfo,
1019                            llvm::raw_fd_ostream::F_Binary);
1020 }
1021 
1022 /// \brief Prune the module cache of modules that haven't been accessed in
1023 /// a long time.
1024 static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
1025   struct stat StatBuf;
1026   llvm::SmallString<128> TimestampFile;
1027   TimestampFile = HSOpts.ModuleCachePath;
1028   llvm::sys::path::append(TimestampFile, "modules.timestamp");
1029 
1030   // Try to stat() the timestamp file.
1031   if (::stat(TimestampFile.c_str(), &StatBuf)) {
1032     // If the timestamp file wasn't there, create one now.
1033     if (errno == ENOENT) {
1034       writeTimestampFile(TimestampFile);
1035     }
1036     return;
1037   }
1038 
1039   // Check whether the time stamp is older than our pruning interval.
1040   // If not, do nothing.
1041   time_t TimeStampModTime = StatBuf.st_mtime;
1042   time_t CurrentTime = time(0);
1043   if (CurrentTime - TimeStampModTime <= time_t(HSOpts.ModuleCachePruneInterval))
1044     return;
1045 
1046   // Write a new timestamp file so that nobody else attempts to prune.
1047   // There is a benign race condition here, if two Clang instances happen to
1048   // notice at the same time that the timestamp is out-of-date.
1049   writeTimestampFile(TimestampFile);
1050 
1051   // Walk the entire module cache, looking for unused module files and module
1052   // indices.
1053   llvm::error_code EC;
1054   SmallString<128> ModuleCachePathNative;
1055   llvm::sys::path::native(HSOpts.ModuleCachePath, ModuleCachePathNative);
1056   for (llvm::sys::fs::directory_iterator
1057          Dir(ModuleCachePathNative.str(), EC), DirEnd;
1058        Dir != DirEnd && !EC; Dir.increment(EC)) {
1059     // If we don't have a directory, there's nothing to look into.
1060     bool IsDirectory;
1061     if (llvm::sys::fs::is_directory(Dir->path(), IsDirectory) || !IsDirectory)
1062       continue;
1063 
1064     // Walk all of the files within this directory.
1065     bool RemovedAllFiles = true;
1066     for (llvm::sys::fs::directory_iterator File(Dir->path(), EC), FileEnd;
1067          File != FileEnd && !EC; File.increment(EC)) {
1068       // We only care about module and global module index files.
1069       if (llvm::sys::path::extension(File->path()) != ".pcm" &&
1070           llvm::sys::path::filename(File->path()) != "modules.idx") {
1071         RemovedAllFiles = false;
1072         continue;
1073       }
1074 
1075       // Look at this file. If we can't stat it, there's nothing interesting
1076       // there.
1077       if (::stat(File->path().c_str(), &StatBuf)) {
1078         RemovedAllFiles = false;
1079         continue;
1080       }
1081 
1082       // If the file has been used recently enough, leave it there.
1083       time_t FileAccessTime = StatBuf.st_atime;
1084       if (CurrentTime - FileAccessTime <=
1085               time_t(HSOpts.ModuleCachePruneAfter)) {
1086         RemovedAllFiles = false;
1087         continue;
1088       }
1089 
1090       // Remove the file.
1091       bool Existed;
1092       if (llvm::sys::fs::remove(File->path(), Existed) || !Existed) {
1093         RemovedAllFiles = false;
1094       }
1095     }
1096 
1097     // If we removed all of the files in the directory, remove the directory
1098     // itself.
1099     if (RemovedAllFiles) {
1100       bool Existed;
1101       llvm::sys::fs::remove(Dir->path(), Existed);
1102     }
1103   }
1104 }
1105 
1106 ModuleLoadResult
1107 CompilerInstance::loadModule(SourceLocation ImportLoc,
1108                              ModuleIdPath Path,
1109                              Module::NameVisibilityKind Visibility,
1110                              bool IsInclusionDirective) {
1111   // If we've already handled this import, just return the cached result.
1112   // This one-element cache is important to eliminate redundant diagnostics
1113   // when both the preprocessor and parser see the same import declaration.
1114   if (!ImportLoc.isInvalid() && LastModuleImportLoc == ImportLoc) {
1115     // Make the named module visible.
1116     if (LastModuleImportResult)
1117       ModuleManager->makeModuleVisible(LastModuleImportResult, Visibility,
1118                                        ImportLoc, /*Complain=*/false);
1119     return LastModuleImportResult;
1120   }
1121 
1122   // Determine what file we're searching from.
1123   StringRef ModuleName = Path[0].first->getName();
1124   SourceLocation ModuleNameLoc = Path[0].second;
1125 
1126   clang::Module *Module = 0;
1127 
1128   // If we don't already have information on this module, load the module now.
1129   llvm::DenseMap<const IdentifierInfo *, clang::Module *>::iterator Known
1130     = KnownModules.find(Path[0].first);
1131   if (Known != KnownModules.end()) {
1132     // Retrieve the cached top-level module.
1133     Module = Known->second;
1134   } else if (ModuleName == getLangOpts().CurrentModule) {
1135     // This is the module we're building.
1136     Module = PP->getHeaderSearchInfo().getModuleMap().findModule(ModuleName);
1137     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1138   } else {
1139     // Search for a module with the given name.
1140     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
1141     std::string ModuleFileName;
1142     if (Module) {
1143       ModuleFileName = PP->getHeaderSearchInfo().getModuleFileName(Module);
1144     } else
1145       ModuleFileName = PP->getHeaderSearchInfo().getModuleFileName(ModuleName);
1146 
1147     // If we don't already have an ASTReader, create one now.
1148     if (!ModuleManager) {
1149       if (!hasASTContext())
1150         createASTContext();
1151 
1152       // If we're not recursively building a module, check whether we
1153       // need to prune the module cache.
1154       if (getSourceManager().getModuleBuildStack().empty() &&
1155           getHeaderSearchOpts().ModuleCachePruneInterval > 0 &&
1156           getHeaderSearchOpts().ModuleCachePruneAfter > 0) {
1157         pruneModuleCache(getHeaderSearchOpts());
1158       }
1159 
1160       std::string Sysroot = getHeaderSearchOpts().Sysroot;
1161       const PreprocessorOptions &PPOpts = getPreprocessorOpts();
1162       ModuleManager = new ASTReader(getPreprocessor(), *Context,
1163                                     Sysroot.empty() ? "" : Sysroot.c_str(),
1164                                     PPOpts.DisablePCHValidation,
1165                                     /*AllowASTWithCompilerErrors=*/false,
1166                                     getFrontendOpts().UseGlobalModuleIndex);
1167       if (hasASTConsumer()) {
1168         ModuleManager->setDeserializationListener(
1169           getASTConsumer().GetASTDeserializationListener());
1170         getASTContext().setASTMutationListener(
1171           getASTConsumer().GetASTMutationListener());
1172       }
1173       OwningPtr<ExternalASTSource> Source;
1174       Source.reset(ModuleManager);
1175       getASTContext().setExternalSource(Source);
1176       if (hasSema())
1177         ModuleManager->InitializeSema(getSema());
1178       if (hasASTConsumer())
1179         ModuleManager->StartTranslationUnit(&getASTConsumer());
1180     }
1181 
1182     // Try to load the module file.
1183     unsigned ARRFlags = ASTReader::ARR_OutOfDate | ASTReader::ARR_Missing;
1184     switch (ModuleManager->ReadAST(ModuleFileName, serialization::MK_Module,
1185                                    ImportLoc, ARRFlags)) {
1186     case ASTReader::Success:
1187       break;
1188 
1189     case ASTReader::OutOfDate: {
1190       // The module file is out-of-date. Remove it, then rebuild it.
1191       bool Existed;
1192       llvm::sys::fs::remove(ModuleFileName, Existed);
1193     }
1194     // Fall through to build the module again.
1195 
1196     case ASTReader::Missing: {
1197       // The module file is (now) missing. Build it.
1198 
1199       // If we don't have a module, we don't know how to build the module file.
1200       // Complain and return.
1201       if (!Module) {
1202         getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_found)
1203           << ModuleName
1204           << SourceRange(ImportLoc, ModuleNameLoc);
1205         ModuleBuildFailed = true;
1206         return ModuleLoadResult();
1207       }
1208 
1209       // Check whether there is a cycle in the module graph.
1210       ModuleBuildStack ModPath = getSourceManager().getModuleBuildStack();
1211       ModuleBuildStack::iterator Pos = ModPath.begin(), PosEnd = ModPath.end();
1212       for (; Pos != PosEnd; ++Pos) {
1213         if (Pos->first == ModuleName)
1214           break;
1215       }
1216 
1217       if (Pos != PosEnd) {
1218         SmallString<256> CyclePath;
1219         for (; Pos != PosEnd; ++Pos) {
1220           CyclePath += Pos->first;
1221           CyclePath += " -> ";
1222         }
1223         CyclePath += ModuleName;
1224 
1225         getDiagnostics().Report(ModuleNameLoc, diag::err_module_cycle)
1226           << ModuleName << CyclePath;
1227         return ModuleLoadResult();
1228       }
1229 
1230       // Check whether we have already attempted to build this module (but
1231       // failed).
1232       if (getPreprocessorOpts().FailedModules &&
1233           getPreprocessorOpts().FailedModules->hasAlreadyFailed(ModuleName)) {
1234         getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_built)
1235           << ModuleName
1236           << SourceRange(ImportLoc, ModuleNameLoc);
1237         ModuleBuildFailed = true;
1238         return ModuleLoadResult();
1239       }
1240 
1241       // Try to compile the module.
1242       compileModule(*this, ModuleNameLoc, Module, ModuleFileName);
1243 
1244       // Try to read the module file, now that we've compiled it.
1245       ASTReader::ASTReadResult ReadResult
1246         = ModuleManager->ReadAST(ModuleFileName,
1247                                  serialization::MK_Module, ImportLoc,
1248                                  ASTReader::ARR_Missing);
1249       if (ReadResult != ASTReader::Success) {
1250         if (ReadResult == ASTReader::Missing) {
1251           getDiagnostics().Report(ModuleNameLoc,
1252                                   Module? diag::err_module_not_built
1253                                         : diag::err_module_not_found)
1254             << ModuleName
1255             << SourceRange(ImportLoc, ModuleNameLoc);
1256         }
1257 
1258         if (getPreprocessorOpts().FailedModules)
1259           getPreprocessorOpts().FailedModules->addFailed(ModuleName);
1260         KnownModules[Path[0].first] = 0;
1261         ModuleBuildFailed = true;
1262         return ModuleLoadResult();
1263       }
1264 
1265       // Okay, we've rebuilt and now loaded the module.
1266       break;
1267     }
1268 
1269     case ASTReader::VersionMismatch:
1270     case ASTReader::ConfigurationMismatch:
1271     case ASTReader::HadErrors:
1272       ModuleLoader::HadFatalFailure = true;
1273       // FIXME: The ASTReader will already have complained, but can we showhorn
1274       // that diagnostic information into a more useful form?
1275       KnownModules[Path[0].first] = 0;
1276       return ModuleLoadResult();
1277 
1278     case ASTReader::Failure:
1279       ModuleLoader::HadFatalFailure = true;
1280       // Already complained, but note now that we failed.
1281       KnownModules[Path[0].first] = 0;
1282       ModuleBuildFailed = true;
1283       return ModuleLoadResult();
1284     }
1285 
1286     if (!Module) {
1287       // If we loaded the module directly, without finding a module map first,
1288       // we'll have loaded the module's information from the module itself.
1289       Module = PP->getHeaderSearchInfo().getModuleMap()
1290                  .findModule((Path[0].first->getName()));
1291     }
1292 
1293     // Cache the result of this top-level module lookup for later.
1294     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1295   }
1296 
1297   // If we never found the module, fail.
1298   if (!Module)
1299     return ModuleLoadResult();
1300 
1301   // Verify that the rest of the module path actually corresponds to
1302   // a submodule.
1303   if (Path.size() > 1) {
1304     for (unsigned I = 1, N = Path.size(); I != N; ++I) {
1305       StringRef Name = Path[I].first->getName();
1306       clang::Module *Sub = Module->findSubmodule(Name);
1307 
1308       if (!Sub) {
1309         // Attempt to perform typo correction to find a module name that works.
1310         SmallVector<StringRef, 2> Best;
1311         unsigned BestEditDistance = (std::numeric_limits<unsigned>::max)();
1312 
1313         for (clang::Module::submodule_iterator J = Module->submodule_begin(),
1314                                             JEnd = Module->submodule_end();
1315              J != JEnd; ++J) {
1316           unsigned ED = Name.edit_distance((*J)->Name,
1317                                            /*AllowReplacements=*/true,
1318                                            BestEditDistance);
1319           if (ED <= BestEditDistance) {
1320             if (ED < BestEditDistance) {
1321               Best.clear();
1322               BestEditDistance = ED;
1323             }
1324 
1325             Best.push_back((*J)->Name);
1326           }
1327         }
1328 
1329         // If there was a clear winner, user it.
1330         if (Best.size() == 1) {
1331           getDiagnostics().Report(Path[I].second,
1332                                   diag::err_no_submodule_suggest)
1333             << Path[I].first << Module->getFullModuleName() << Best[0]
1334             << SourceRange(Path[0].second, Path[I-1].second)
1335             << FixItHint::CreateReplacement(SourceRange(Path[I].second),
1336                                             Best[0]);
1337 
1338           Sub = Module->findSubmodule(Best[0]);
1339         }
1340       }
1341 
1342       if (!Sub) {
1343         // No submodule by this name. Complain, and don't look for further
1344         // submodules.
1345         getDiagnostics().Report(Path[I].second, diag::err_no_submodule)
1346           << Path[I].first << Module->getFullModuleName()
1347           << SourceRange(Path[0].second, Path[I-1].second);
1348         break;
1349       }
1350 
1351       Module = Sub;
1352     }
1353   }
1354 
1355   // Make the named module visible, if it's not already part of the module
1356   // we are parsing.
1357   if (ModuleName != getLangOpts().CurrentModule) {
1358     if (!Module->IsFromModuleFile) {
1359       // We have an umbrella header or directory that doesn't actually include
1360       // all of the headers within the directory it covers. Complain about
1361       // this missing submodule and recover by forgetting that we ever saw
1362       // this submodule.
1363       // FIXME: Should we detect this at module load time? It seems fairly
1364       // expensive (and rare).
1365       getDiagnostics().Report(ImportLoc, diag::warn_missing_submodule)
1366         << Module->getFullModuleName()
1367         << SourceRange(Path.front().second, Path.back().second);
1368 
1369       return ModuleLoadResult(0, true);
1370     }
1371 
1372     // Check whether this module is available.
1373     StringRef Feature;
1374     if (!Module->isAvailable(getLangOpts(), getTarget(), Feature)) {
1375       getDiagnostics().Report(ImportLoc, diag::err_module_unavailable)
1376         << Module->getFullModuleName()
1377         << Feature
1378         << SourceRange(Path.front().second, Path.back().second);
1379       LastModuleImportLoc = ImportLoc;
1380       LastModuleImportResult = ModuleLoadResult();
1381       return ModuleLoadResult();
1382     }
1383 
1384     ModuleManager->makeModuleVisible(Module, Visibility, ImportLoc,
1385                                      /*Complain=*/true);
1386   }
1387 
1388   // Check for any configuration macros that have changed.
1389   clang::Module *TopModule = Module->getTopLevelModule();
1390   for (unsigned I = 0, N = TopModule->ConfigMacros.size(); I != N; ++I) {
1391     checkConfigMacro(getPreprocessor(), TopModule->ConfigMacros[I],
1392                      Module, ImportLoc);
1393   }
1394 
1395   // If this module import was due to an inclusion directive, create an
1396   // implicit import declaration to capture it in the AST.
1397   if (IsInclusionDirective && hasASTContext()) {
1398     TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
1399     ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
1400                                                      ImportLoc, Module,
1401                                                      Path.back().second);
1402     TU->addDecl(ImportD);
1403     if (Consumer)
1404       Consumer->HandleImplicitImportDecl(ImportD);
1405   }
1406 
1407   LastModuleImportLoc = ImportLoc;
1408   LastModuleImportResult = ModuleLoadResult(Module, false);
1409   return LastModuleImportResult;
1410 }
1411 
1412 void CompilerInstance::makeModuleVisible(Module *Mod,
1413                                          Module::NameVisibilityKind Visibility,
1414                                          SourceLocation ImportLoc,
1415                                          bool Complain){
1416   ModuleManager->makeModuleVisible(Mod, Visibility, ImportLoc, Complain);
1417 }
1418 
1419