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