xref: /llvm-project/clang/lib/Frontend/CompilerInstance.cpp (revision d4b230b3780bf645991e99986a510124f64dabed)
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/Config/config.h"
20 #include "clang/Frontend/ChainedDiagnosticConsumer.h"
21 #include "clang/Frontend/FrontendAction.h"
22 #include "clang/Frontend/FrontendActions.h"
23 #include "clang/Frontend/FrontendDiagnostic.h"
24 #include "clang/Frontend/LogDiagnosticPrinter.h"
25 #include "clang/Frontend/SerializedDiagnosticPrinter.h"
26 #include "clang/Frontend/TextDiagnosticPrinter.h"
27 #include "clang/Frontend/Utils.h"
28 #include "clang/Frontend/VerifyDiagnosticConsumer.h"
29 #include "clang/Lex/HeaderSearch.h"
30 #include "clang/Lex/PTHManager.h"
31 #include "clang/Lex/Preprocessor.h"
32 #include "clang/Sema/CodeCompleteConsumer.h"
33 #include "clang/Sema/Sema.h"
34 #include "clang/Serialization/ASTReader.h"
35 #include "clang/Serialization/GlobalModuleIndex.h"
36 #include "llvm/ADT/Statistic.h"
37 #include "llvm/Support/CrashRecoveryContext.h"
38 #include "llvm/Support/Errc.h"
39 #include "llvm/Support/FileSystem.h"
40 #include "llvm/Support/Host.h"
41 #include "llvm/Support/LockFileManager.h"
42 #include "llvm/Support/MemoryBuffer.h"
43 #include "llvm/Support/Path.h"
44 #include "llvm/Support/Program.h"
45 #include "llvm/Support/Signals.h"
46 #include "llvm/Support/Timer.h"
47 #include "llvm/Support/raw_ostream.h"
48 #include <sys/stat.h>
49 #include <system_error>
50 #include <time.h>
51 
52 using namespace clang;
53 
54 CompilerInstance::CompilerInstance(bool BuildingModule)
55   : ModuleLoader(BuildingModule),
56     Invocation(new CompilerInvocation()), ModuleManager(nullptr),
57     BuildGlobalModuleIndex(false), HaveFullGlobalModuleIndex(false),
58     ModuleBuildFailed(false) {
59 }
60 
61 CompilerInstance::~CompilerInstance() {
62   assert(OutputFiles.empty() && "Still output files in flight?");
63 }
64 
65 void CompilerInstance::setInvocation(CompilerInvocation *Value) {
66   Invocation = Value;
67 }
68 
69 bool CompilerInstance::shouldBuildGlobalModuleIndex() const {
70   return (BuildGlobalModuleIndex ||
71           (ModuleManager && ModuleManager->isGlobalIndexUnavailable() &&
72            getFrontendOpts().GenerateGlobalModuleIndex)) &&
73          !ModuleBuildFailed;
74 }
75 
76 void CompilerInstance::setDiagnostics(DiagnosticsEngine *Value) {
77   Diagnostics = Value;
78 }
79 
80 void CompilerInstance::setTarget(TargetInfo *Value) {
81   Target = Value;
82 }
83 
84 void CompilerInstance::setFileManager(FileManager *Value) {
85   FileMgr = Value;
86   if (Value)
87     VirtualFileSystem = Value->getVirtualFileSystem();
88   else
89     VirtualFileSystem.reset();
90 }
91 
92 void CompilerInstance::setSourceManager(SourceManager *Value) {
93   SourceMgr = Value;
94 }
95 
96 void CompilerInstance::setPreprocessor(Preprocessor *Value) { PP = Value; }
97 
98 void CompilerInstance::setASTContext(ASTContext *Value) { Context = Value; }
99 
100 void CompilerInstance::setSema(Sema *S) {
101   TheSema.reset(S);
102 }
103 
104 void CompilerInstance::setASTConsumer(std::unique_ptr<ASTConsumer> Value) {
105   Consumer = std::move(Value);
106 }
107 
108 void CompilerInstance::setCodeCompletionConsumer(CodeCompleteConsumer *Value) {
109   CompletionConsumer.reset(Value);
110 }
111 
112 std::unique_ptr<Sema> CompilerInstance::takeSema() {
113   return std::move(TheSema);
114 }
115 
116 IntrusiveRefCntPtr<ASTReader> CompilerInstance::getModuleManager() const {
117   return ModuleManager;
118 }
119 void CompilerInstance::setModuleManager(IntrusiveRefCntPtr<ASTReader> Reader) {
120   ModuleManager = Reader;
121 }
122 
123 std::shared_ptr<ModuleDependencyCollector>
124 CompilerInstance::getModuleDepCollector() const {
125   return ModuleDepCollector;
126 }
127 
128 void CompilerInstance::setModuleDepCollector(
129     std::shared_ptr<ModuleDependencyCollector> Collector) {
130   ModuleDepCollector = Collector;
131 }
132 
133 // Diagnostics
134 static void SetUpDiagnosticLog(DiagnosticOptions *DiagOpts,
135                                const CodeGenOptions *CodeGenOpts,
136                                DiagnosticsEngine &Diags) {
137   std::error_code EC;
138   std::unique_ptr<raw_ostream> StreamOwner;
139   raw_ostream *OS = &llvm::errs();
140   if (DiagOpts->DiagnosticLogFile != "-") {
141     // Create the output stream.
142     auto FileOS = llvm::make_unique<llvm::raw_fd_ostream>(
143         DiagOpts->DiagnosticLogFile, EC,
144         llvm::sys::fs::F_Append | llvm::sys::fs::F_Text);
145     if (EC) {
146       Diags.Report(diag::warn_fe_cc_log_diagnostics_failure)
147           << DiagOpts->DiagnosticLogFile << EC.message();
148     } else {
149       FileOS->SetUnbuffered();
150       FileOS->SetUseAtomicWrites(true);
151       OS = FileOS.get();
152       StreamOwner = std::move(FileOS);
153     }
154   }
155 
156   // Chain in the diagnostic client which will log the diagnostics.
157   auto Logger = llvm::make_unique<LogDiagnosticPrinter>(*OS, DiagOpts,
158                                                         std::move(StreamOwner));
159   if (CodeGenOpts)
160     Logger->setDwarfDebugFlags(CodeGenOpts->DwarfDebugFlags);
161   assert(Diags.ownsClient());
162   Diags.setClient(new ChainedDiagnosticConsumer(
163       std::unique_ptr<DiagnosticConsumer>(Diags.takeClient()),
164       std::move(Logger)));
165 }
166 
167 static void SetupSerializedDiagnostics(DiagnosticOptions *DiagOpts,
168                                        DiagnosticsEngine &Diags,
169                                        StringRef OutputFile) {
170   auto SerializedConsumer =
171       clang::serialized_diags::create(OutputFile, DiagOpts);
172 
173   assert(Diags.ownsClient());
174   Diags.setClient(new ChainedDiagnosticConsumer(
175       std::unique_ptr<DiagnosticConsumer>(Diags.takeClient()),
176       std::move(SerializedConsumer)));
177 }
178 
179 void CompilerInstance::createDiagnostics(DiagnosticConsumer *Client,
180                                          bool ShouldOwnClient) {
181   Diagnostics = createDiagnostics(&getDiagnosticOpts(), Client,
182                                   ShouldOwnClient, &getCodeGenOpts());
183 }
184 
185 IntrusiveRefCntPtr<DiagnosticsEngine>
186 CompilerInstance::createDiagnostics(DiagnosticOptions *Opts,
187                                     DiagnosticConsumer *Client,
188                                     bool ShouldOwnClient,
189                                     const CodeGenOptions *CodeGenOpts) {
190   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
191   IntrusiveRefCntPtr<DiagnosticsEngine>
192       Diags(new DiagnosticsEngine(DiagID, Opts));
193 
194   // Create the diagnostic client for reporting errors or for
195   // implementing -verify.
196   if (Client) {
197     Diags->setClient(Client, ShouldOwnClient);
198   } else
199     Diags->setClient(new TextDiagnosticPrinter(llvm::errs(), Opts));
200 
201   // Chain in -verify checker, if requested.
202   if (Opts->VerifyDiagnostics)
203     Diags->setClient(new VerifyDiagnosticConsumer(*Diags));
204 
205   // Chain in -diagnostic-log-file dumper, if requested.
206   if (!Opts->DiagnosticLogFile.empty())
207     SetUpDiagnosticLog(Opts, CodeGenOpts, *Diags);
208 
209   if (!Opts->DiagnosticSerializationFile.empty())
210     SetupSerializedDiagnostics(Opts, *Diags,
211                                Opts->DiagnosticSerializationFile);
212 
213   // Configure our handling of diagnostics.
214   ProcessWarningOptions(*Diags, *Opts);
215 
216   return Diags;
217 }
218 
219 // File Manager
220 
221 void CompilerInstance::createFileManager() {
222   if (!hasVirtualFileSystem()) {
223     // TODO: choose the virtual file system based on the CompilerInvocation.
224     setVirtualFileSystem(vfs::getRealFileSystem());
225   }
226   FileMgr = new FileManager(getFileSystemOpts(), VirtualFileSystem);
227 }
228 
229 // Source Manager
230 
231 void CompilerInstance::createSourceManager(FileManager &FileMgr) {
232   SourceMgr = new SourceManager(getDiagnostics(), FileMgr);
233 }
234 
235 // Initialize the remapping of files to alternative contents, e.g.,
236 // those specified through other files.
237 static void InitializeFileRemapping(DiagnosticsEngine &Diags,
238                                     SourceManager &SourceMgr,
239                                     FileManager &FileMgr,
240                                     const PreprocessorOptions &InitOpts) {
241   // Remap files in the source manager (with buffers).
242   for (const auto &RB : InitOpts.RemappedFileBuffers) {
243     // Create the file entry for the file that we're mapping from.
244     const FileEntry *FromFile =
245         FileMgr.getVirtualFile(RB.first, RB.second->getBufferSize(), 0);
246     if (!FromFile) {
247       Diags.Report(diag::err_fe_remap_missing_from_file) << RB.first;
248       if (!InitOpts.RetainRemappedFileBuffers)
249         delete RB.second;
250       continue;
251     }
252 
253     // Override the contents of the "from" file with the contents of
254     // the "to" file.
255     SourceMgr.overrideFileContents(FromFile, RB.second,
256                                    InitOpts.RetainRemappedFileBuffers);
257   }
258 
259   // Remap files in the source manager (with other files).
260   for (const auto &RF : InitOpts.RemappedFiles) {
261     // Find the file that we're mapping to.
262     const FileEntry *ToFile = FileMgr.getFile(RF.second);
263     if (!ToFile) {
264       Diags.Report(diag::err_fe_remap_missing_to_file) << RF.first << RF.second;
265       continue;
266     }
267 
268     // Create the file entry for the file that we're mapping from.
269     const FileEntry *FromFile =
270         FileMgr.getVirtualFile(RF.first, ToFile->getSize(), 0);
271     if (!FromFile) {
272       Diags.Report(diag::err_fe_remap_missing_from_file) << RF.first;
273       continue;
274     }
275 
276     // Override the contents of the "from" file with the contents of
277     // the "to" file.
278     SourceMgr.overrideFileContents(FromFile, ToFile);
279   }
280 
281   SourceMgr.setOverridenFilesKeepOriginalName(
282       InitOpts.RemappedFilesKeepOriginalName);
283 }
284 
285 // Preprocessor
286 
287 void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
288   const PreprocessorOptions &PPOpts = getPreprocessorOpts();
289 
290   // Create a PTH manager if we are using some form of a token cache.
291   PTHManager *PTHMgr = nullptr;
292   if (!PPOpts.TokenCache.empty())
293     PTHMgr = PTHManager::Create(PPOpts.TokenCache, getDiagnostics());
294 
295   // Create the Preprocessor.
296   HeaderSearch *HeaderInfo = new HeaderSearch(&getHeaderSearchOpts(),
297                                               getSourceManager(),
298                                               getDiagnostics(),
299                                               getLangOpts(),
300                                               &getTarget());
301   PP = new Preprocessor(&getPreprocessorOpts(), getDiagnostics(), getLangOpts(),
302                         getSourceManager(), *HeaderInfo, *this, PTHMgr,
303                         /*OwnsHeaderSearch=*/true, TUKind);
304   PP->Initialize(getTarget());
305 
306   // Note that this is different then passing PTHMgr to Preprocessor's ctor.
307   // That argument is used as the IdentifierInfoLookup argument to
308   // IdentifierTable's ctor.
309   if (PTHMgr) {
310     PTHMgr->setPreprocessor(&*PP);
311     PP->setPTHManager(PTHMgr);
312   }
313 
314   if (PPOpts.DetailedRecord)
315     PP->createPreprocessingRecord();
316 
317   // Apply remappings to the source manager.
318   InitializeFileRemapping(PP->getDiagnostics(), PP->getSourceManager(),
319                           PP->getFileManager(), PPOpts);
320 
321   // Predefine macros and configure the preprocessor.
322   InitializePreprocessor(*PP, PPOpts, getFrontendOpts());
323 
324   // Initialize the header search object.
325   ApplyHeaderSearchOptions(PP->getHeaderSearchInfo(), getHeaderSearchOpts(),
326                            PP->getLangOpts(), PP->getTargetInfo().getTriple());
327 
328   PP->setPreprocessedOutput(getPreprocessorOutputOpts().ShowCPP);
329 
330   // Set up the module path, including the hash for the
331   // module-creation options.
332   SmallString<256> SpecificModuleCache(
333                            getHeaderSearchOpts().ModuleCachePath);
334   if (!getHeaderSearchOpts().DisableModuleHash)
335     llvm::sys::path::append(SpecificModuleCache,
336                             getInvocation().getModuleHash());
337   PP->getHeaderSearchInfo().setModuleCachePath(SpecificModuleCache);
338 
339   // Handle generating dependencies, if requested.
340   const DependencyOutputOptions &DepOpts = getDependencyOutputOpts();
341   if (!DepOpts.OutputFile.empty())
342     TheDependencyFileGenerator.reset(
343         DependencyFileGenerator::CreateAndAttachToPreprocessor(*PP, DepOpts));
344   if (!DepOpts.DOTOutputFile.empty())
345     AttachDependencyGraphGen(*PP, DepOpts.DOTOutputFile,
346                              getHeaderSearchOpts().Sysroot);
347 
348   for (auto &Listener : DependencyCollectors)
349     Listener->attachToPreprocessor(*PP);
350 
351   // If we don't have a collector, but we are collecting module dependencies,
352   // then we're the top level compiler instance and need to create one.
353   if (!ModuleDepCollector && !DepOpts.ModuleDependencyOutputDir.empty())
354     ModuleDepCollector = std::make_shared<ModuleDependencyCollector>(
355         DepOpts.ModuleDependencyOutputDir);
356 
357   // Handle generating header include information, if requested.
358   if (DepOpts.ShowHeaderIncludes)
359     AttachHeaderIncludeGen(*PP);
360   if (!DepOpts.HeaderIncludeOutputFile.empty()) {
361     StringRef OutputPath = DepOpts.HeaderIncludeOutputFile;
362     if (OutputPath == "-")
363       OutputPath = "";
364     AttachHeaderIncludeGen(*PP, /*ShowAllHeaders=*/true, OutputPath,
365                            /*ShowDepth=*/false);
366   }
367 
368   if (DepOpts.PrintShowIncludes) {
369     AttachHeaderIncludeGen(*PP, /*ShowAllHeaders=*/false, /*OutputPath=*/"",
370                            /*ShowDepth=*/true, /*MSStyle=*/true);
371   }
372 }
373 
374 // ASTContext
375 
376 void CompilerInstance::createASTContext() {
377   Preprocessor &PP = getPreprocessor();
378   Context = new ASTContext(getLangOpts(), PP.getSourceManager(),
379                            PP.getIdentifierTable(), PP.getSelectorTable(),
380                            PP.getBuiltinInfo());
381   Context->InitBuiltinTypes(getTarget());
382 }
383 
384 // ExternalASTSource
385 
386 void CompilerInstance::createPCHExternalASTSource(
387     StringRef Path, bool DisablePCHValidation, bool AllowPCHWithCompilerErrors,
388     void *DeserializationListener, bool OwnDeserializationListener) {
389   IntrusiveRefCntPtr<ExternalASTSource> Source;
390   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
391   Source = createPCHExternalASTSource(
392       Path, getHeaderSearchOpts().Sysroot, DisablePCHValidation,
393       AllowPCHWithCompilerErrors, getPreprocessor(), getASTContext(),
394       DeserializationListener, OwnDeserializationListener, Preamble,
395       getFrontendOpts().UseGlobalModuleIndex);
396   ModuleManager = static_cast<ASTReader*>(Source.get());
397   getASTContext().setExternalSource(Source);
398 }
399 
400 ExternalASTSource *CompilerInstance::createPCHExternalASTSource(
401     StringRef Path, const std::string &Sysroot, bool DisablePCHValidation,
402     bool AllowPCHWithCompilerErrors, Preprocessor &PP, ASTContext &Context,
403     void *DeserializationListener, bool OwnDeserializationListener,
404     bool Preamble, bool UseGlobalModuleIndex) {
405   HeaderSearchOptions &HSOpts = PP.getHeaderSearchInfo().getHeaderSearchOpts();
406 
407   std::unique_ptr<ASTReader> Reader;
408   Reader.reset(new ASTReader(PP, Context,
409                              Sysroot.empty() ? "" : Sysroot.c_str(),
410                              DisablePCHValidation,
411                              AllowPCHWithCompilerErrors,
412                              /*AllowConfigurationMismatch*/false,
413                              HSOpts.ModulesValidateSystemHeaders,
414                              UseGlobalModuleIndex));
415 
416   Reader->setDeserializationListener(
417       static_cast<ASTDeserializationListener *>(DeserializationListener),
418       /*TakeOwnership=*/OwnDeserializationListener);
419   switch (Reader->ReadAST(Path,
420                           Preamble ? serialization::MK_Preamble
421                                    : serialization::MK_PCH,
422                           SourceLocation(),
423                           ASTReader::ARR_None)) {
424   case ASTReader::Success:
425     // Set the predefines buffer as suggested by the PCH reader. Typically, the
426     // predefines buffer will be empty.
427     PP.setPredefines(Reader->getSuggestedPredefines());
428     return Reader.release();
429 
430   case ASTReader::Failure:
431     // Unrecoverable failure: don't even try to process the input file.
432     break;
433 
434   case ASTReader::Missing:
435   case ASTReader::OutOfDate:
436   case ASTReader::VersionMismatch:
437   case ASTReader::ConfigurationMismatch:
438   case ASTReader::HadErrors:
439     // No suitable PCH file could be found. Return an error.
440     break;
441   }
442 
443   return nullptr;
444 }
445 
446 // Code Completion
447 
448 static bool EnableCodeCompletion(Preprocessor &PP,
449                                  const std::string &Filename,
450                                  unsigned Line,
451                                  unsigned Column) {
452   // Tell the source manager to chop off the given file at a specific
453   // line and column.
454   const FileEntry *Entry = PP.getFileManager().getFile(Filename);
455   if (!Entry) {
456     PP.getDiagnostics().Report(diag::err_fe_invalid_code_complete_file)
457       << Filename;
458     return true;
459   }
460 
461   // Truncate the named file at the given line/column.
462   PP.SetCodeCompletionPoint(Entry, Line, Column);
463   return false;
464 }
465 
466 void CompilerInstance::createCodeCompletionConsumer() {
467   const ParsedSourceLocation &Loc = getFrontendOpts().CodeCompletionAt;
468   if (!CompletionConsumer) {
469     setCodeCompletionConsumer(
470       createCodeCompletionConsumer(getPreprocessor(),
471                                    Loc.FileName, Loc.Line, Loc.Column,
472                                    getFrontendOpts().CodeCompleteOpts,
473                                    llvm::outs()));
474     if (!CompletionConsumer)
475       return;
476   } else if (EnableCodeCompletion(getPreprocessor(), Loc.FileName,
477                                   Loc.Line, Loc.Column)) {
478     setCodeCompletionConsumer(nullptr);
479     return;
480   }
481 
482   if (CompletionConsumer->isOutputBinary() &&
483       llvm::sys::ChangeStdoutToBinary()) {
484     getPreprocessor().getDiagnostics().Report(diag::err_fe_stdout_binary);
485     setCodeCompletionConsumer(nullptr);
486   }
487 }
488 
489 void CompilerInstance::createFrontendTimer() {
490   FrontendTimer.reset(new llvm::Timer("Clang front-end timer"));
491 }
492 
493 CodeCompleteConsumer *
494 CompilerInstance::createCodeCompletionConsumer(Preprocessor &PP,
495                                                const std::string &Filename,
496                                                unsigned Line,
497                                                unsigned Column,
498                                                const CodeCompleteOptions &Opts,
499                                                raw_ostream &OS) {
500   if (EnableCodeCompletion(PP, Filename, Line, Column))
501     return nullptr;
502 
503   // Set up the creation routine for code-completion.
504   return new PrintingCodeCompleteConsumer(Opts, OS);
505 }
506 
507 void CompilerInstance::createSema(TranslationUnitKind TUKind,
508                                   CodeCompleteConsumer *CompletionConsumer) {
509   TheSema.reset(new Sema(getPreprocessor(), getASTContext(), getASTConsumer(),
510                          TUKind, CompletionConsumer));
511 }
512 
513 // Output Files
514 
515 void CompilerInstance::addOutputFile(const OutputFile &OutFile) {
516   assert(OutFile.OS && "Attempt to add empty stream to output list!");
517   OutputFiles.push_back(OutFile);
518 }
519 
520 void CompilerInstance::clearOutputFiles(bool EraseFiles) {
521   for (std::list<OutputFile>::iterator
522          it = OutputFiles.begin(), ie = OutputFiles.end(); it != ie; ++it) {
523     delete it->OS;
524     if (!it->TempFilename.empty()) {
525       if (EraseFiles) {
526         llvm::sys::fs::remove(it->TempFilename);
527       } else {
528         SmallString<128> NewOutFile(it->Filename);
529 
530         // If '-working-directory' was passed, the output filename should be
531         // relative to that.
532         FileMgr->FixupRelativePath(NewOutFile);
533         if (std::error_code ec =
534                 llvm::sys::fs::rename(it->TempFilename, NewOutFile.str())) {
535           getDiagnostics().Report(diag::err_unable_to_rename_temp)
536             << it->TempFilename << it->Filename << ec.message();
537 
538           llvm::sys::fs::remove(it->TempFilename);
539         }
540       }
541     } else if (!it->Filename.empty() && EraseFiles)
542       llvm::sys::fs::remove(it->Filename);
543 
544   }
545   OutputFiles.clear();
546 }
547 
548 llvm::raw_fd_ostream *
549 CompilerInstance::createDefaultOutputFile(bool Binary,
550                                           StringRef InFile,
551                                           StringRef Extension) {
552   return createOutputFile(getFrontendOpts().OutputFile, Binary,
553                           /*RemoveFileOnSignal=*/true, InFile, Extension,
554                           /*UseTemporary=*/true);
555 }
556 
557 llvm::raw_null_ostream *CompilerInstance::createNullOutputFile() {
558   llvm::raw_null_ostream *OS = new llvm::raw_null_ostream();
559   addOutputFile(OutputFile("", "", OS));
560   return OS;
561 }
562 
563 llvm::raw_fd_ostream *
564 CompilerInstance::createOutputFile(StringRef OutputPath,
565                                    bool Binary, bool RemoveFileOnSignal,
566                                    StringRef InFile,
567                                    StringRef Extension,
568                                    bool UseTemporary,
569                                    bool CreateMissingDirectories) {
570   std::string OutputPathName, TempPathName;
571   std::error_code EC;
572   llvm::raw_fd_ostream *OS = createOutputFile(
573       OutputPath, EC, Binary, RemoveFileOnSignal, InFile, Extension,
574       UseTemporary, CreateMissingDirectories, &OutputPathName, &TempPathName);
575   if (!OS) {
576     getDiagnostics().Report(diag::err_fe_unable_to_open_output) << OutputPath
577                                                                 << EC.message();
578     return nullptr;
579   }
580 
581   // Add the output file -- but don't try to remove "-", since this means we are
582   // using stdin.
583   addOutputFile(OutputFile((OutputPathName != "-") ? OutputPathName : "",
584                 TempPathName, OS));
585 
586   return OS;
587 }
588 
589 llvm::raw_fd_ostream *CompilerInstance::createOutputFile(
590     StringRef OutputPath, std::error_code &Error, bool Binary,
591     bool RemoveFileOnSignal, StringRef InFile, StringRef Extension,
592     bool UseTemporary, bool CreateMissingDirectories,
593     std::string *ResultPathName, std::string *TempPathName) {
594   assert((!CreateMissingDirectories || UseTemporary) &&
595          "CreateMissingDirectories is only allowed when using temporary files");
596 
597   std::string OutFile, TempFile;
598   if (!OutputPath.empty()) {
599     OutFile = OutputPath;
600   } else if (InFile == "-") {
601     OutFile = "-";
602   } else if (!Extension.empty()) {
603     SmallString<128> Path(InFile);
604     llvm::sys::path::replace_extension(Path, Extension);
605     OutFile = Path.str();
606   } else {
607     OutFile = "-";
608   }
609 
610   std::unique_ptr<llvm::raw_fd_ostream> OS;
611   std::string OSFile;
612 
613   if (UseTemporary) {
614     if (OutFile == "-")
615       UseTemporary = false;
616     else {
617       llvm::sys::fs::file_status Status;
618       llvm::sys::fs::status(OutputPath, Status);
619       if (llvm::sys::fs::exists(Status)) {
620         // Fail early if we can't write to the final destination.
621         if (!llvm::sys::fs::can_write(OutputPath))
622           return nullptr;
623 
624         // Don't use a temporary if the output is a special file. This handles
625         // things like '-o /dev/null'
626         if (!llvm::sys::fs::is_regular_file(Status))
627           UseTemporary = false;
628       }
629     }
630   }
631 
632   if (UseTemporary) {
633     // Create a temporary file.
634     SmallString<128> TempPath;
635     TempPath = OutFile;
636     TempPath += "-%%%%%%%%";
637     int fd;
638     std::error_code EC =
639         llvm::sys::fs::createUniqueFile(TempPath.str(), fd, TempPath);
640 
641     if (CreateMissingDirectories &&
642         EC == llvm::errc::no_such_file_or_directory) {
643       StringRef Parent = llvm::sys::path::parent_path(OutputPath);
644       EC = llvm::sys::fs::create_directories(Parent);
645       if (!EC) {
646         EC = llvm::sys::fs::createUniqueFile(TempPath.str(), fd, TempPath);
647       }
648     }
649 
650     if (!EC) {
651       OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
652       OSFile = TempFile = TempPath.str();
653     }
654     // If we failed to create the temporary, fallback to writing to the file
655     // directly. This handles the corner case where we cannot write to the
656     // directory, but can write to the file.
657   }
658 
659   if (!OS) {
660     OSFile = OutFile;
661     OS.reset(new llvm::raw_fd_ostream(
662         OSFile, Error,
663         (Binary ? llvm::sys::fs::F_None : llvm::sys::fs::F_Text)));
664     if (Error)
665       return nullptr;
666   }
667 
668   // Make sure the out stream file gets removed if we crash.
669   if (RemoveFileOnSignal)
670     llvm::sys::RemoveFileOnSignal(OSFile);
671 
672   if (ResultPathName)
673     *ResultPathName = OutFile;
674   if (TempPathName)
675     *TempPathName = TempFile;
676 
677   return OS.release();
678 }
679 
680 // Initialization Utilities
681 
682 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input){
683   return InitializeSourceManager(Input, getDiagnostics(),
684                                  getFileManager(), getSourceManager(),
685                                  getFrontendOpts());
686 }
687 
688 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input,
689                                                DiagnosticsEngine &Diags,
690                                                FileManager &FileMgr,
691                                                SourceManager &SourceMgr,
692                                                const FrontendOptions &Opts) {
693   SrcMgr::CharacteristicKind
694     Kind = Input.isSystem() ? SrcMgr::C_System : SrcMgr::C_User;
695 
696   if (Input.isBuffer()) {
697     SourceMgr.setMainFileID(SourceMgr.createFileID(
698         std::unique_ptr<llvm::MemoryBuffer>(Input.getBuffer()), Kind));
699     assert(!SourceMgr.getMainFileID().isInvalid() &&
700            "Couldn't establish MainFileID!");
701     return true;
702   }
703 
704   StringRef InputFile = Input.getFile();
705 
706   // Figure out where to get and map in the main file.
707   if (InputFile != "-") {
708     const FileEntry *File = FileMgr.getFile(InputFile, /*OpenFile=*/true);
709     if (!File) {
710       Diags.Report(diag::err_fe_error_reading) << InputFile;
711       return false;
712     }
713 
714     // The natural SourceManager infrastructure can't currently handle named
715     // pipes, but we would at least like to accept them for the main
716     // file. Detect them here, read them with the volatile flag so FileMgr will
717     // pick up the correct size, and simply override their contents as we do for
718     // STDIN.
719     if (File->isNamedPipe()) {
720       auto MB = FileMgr.getBufferForFile(File, /*isVolatile=*/true);
721       if (MB) {
722         // Create a new virtual file that will have the correct size.
723         File = FileMgr.getVirtualFile(InputFile, (*MB)->getBufferSize(), 0);
724         SourceMgr.overrideFileContents(File, std::move(*MB));
725       } else {
726         Diags.Report(diag::err_cannot_open_file) << InputFile
727                                                  << MB.getError().message();
728         return false;
729       }
730     }
731 
732     SourceMgr.setMainFileID(
733         SourceMgr.createFileID(File, SourceLocation(), Kind));
734   } else {
735     llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> SBOrErr =
736         llvm::MemoryBuffer::getSTDIN();
737     if (std::error_code EC = SBOrErr.getError()) {
738       Diags.Report(diag::err_fe_error_reading_stdin) << EC.message();
739       return false;
740     }
741     std::unique_ptr<llvm::MemoryBuffer> SB = std::move(SBOrErr.get());
742 
743     const FileEntry *File = FileMgr.getVirtualFile(SB->getBufferIdentifier(),
744                                                    SB->getBufferSize(), 0);
745     SourceMgr.setMainFileID(
746         SourceMgr.createFileID(File, SourceLocation(), Kind));
747     SourceMgr.overrideFileContents(File, std::move(SB));
748   }
749 
750   assert(!SourceMgr.getMainFileID().isInvalid() &&
751          "Couldn't establish MainFileID!");
752   return true;
753 }
754 
755 // High-Level Operations
756 
757 bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
758   assert(hasDiagnostics() && "Diagnostics engine is not initialized!");
759   assert(!getFrontendOpts().ShowHelp && "Client must handle '-help'!");
760   assert(!getFrontendOpts().ShowVersion && "Client must handle '-version'!");
761 
762   // FIXME: Take this as an argument, once all the APIs we used have moved to
763   // taking it as an input instead of hard-coding llvm::errs.
764   raw_ostream &OS = llvm::errs();
765 
766   // Create the target instance.
767   setTarget(TargetInfo::CreateTargetInfo(getDiagnostics(),
768                                          getInvocation().TargetOpts));
769   if (!hasTarget())
770     return false;
771 
772   // Inform the target of the language options.
773   //
774   // FIXME: We shouldn't need to do this, the target should be immutable once
775   // created. This complexity should be lifted elsewhere.
776   getTarget().adjust(getLangOpts());
777 
778   // rewriter project will change target built-in bool type from its default.
779   if (getFrontendOpts().ProgramAction == frontend::RewriteObjC)
780     getTarget().noSignedCharForObjCBool();
781 
782   // Validate/process some options.
783   if (getHeaderSearchOpts().Verbose)
784     OS << "clang -cc1 version " CLANG_VERSION_STRING
785        << " based upon " << BACKEND_PACKAGE_STRING
786        << " default target " << llvm::sys::getDefaultTargetTriple() << "\n";
787 
788   if (getFrontendOpts().ShowTimers)
789     createFrontendTimer();
790 
791   if (getFrontendOpts().ShowStats)
792     llvm::EnableStatistics();
793 
794   for (unsigned i = 0, e = getFrontendOpts().Inputs.size(); i != e; ++i) {
795     // Reset the ID tables if we are reusing the SourceManager and parsing
796     // regular files.
797     if (hasSourceManager() && !Act.isModelParsingAction())
798       getSourceManager().clearIDTables();
799 
800     if (Act.BeginSourceFile(*this, getFrontendOpts().Inputs[i])) {
801       Act.Execute();
802       Act.EndSourceFile();
803     }
804   }
805 
806   // Notify the diagnostic client that all files were processed.
807   getDiagnostics().getClient()->finish();
808 
809   if (getDiagnosticOpts().ShowCarets) {
810     // We can have multiple diagnostics sharing one diagnostic client.
811     // Get the total number of warnings/errors from the client.
812     unsigned NumWarnings = getDiagnostics().getClient()->getNumWarnings();
813     unsigned NumErrors = getDiagnostics().getClient()->getNumErrors();
814 
815     if (NumWarnings)
816       OS << NumWarnings << " warning" << (NumWarnings == 1 ? "" : "s");
817     if (NumWarnings && NumErrors)
818       OS << " and ";
819     if (NumErrors)
820       OS << NumErrors << " error" << (NumErrors == 1 ? "" : "s");
821     if (NumWarnings || NumErrors)
822       OS << " generated.\n";
823   }
824 
825   if (getFrontendOpts().ShowStats && hasFileManager()) {
826     getFileManager().PrintStats();
827     OS << "\n";
828   }
829 
830   return !getDiagnostics().getClient()->getNumErrors();
831 }
832 
833 /// \brief Determine the appropriate source input kind based on language
834 /// options.
835 static InputKind getSourceInputKindFromOptions(const LangOptions &LangOpts) {
836   if (LangOpts.OpenCL)
837     return IK_OpenCL;
838   if (LangOpts.CUDA)
839     return IK_CUDA;
840   if (LangOpts.ObjC1)
841     return LangOpts.CPlusPlus? IK_ObjCXX : IK_ObjC;
842   return LangOpts.CPlusPlus? IK_CXX : IK_C;
843 }
844 
845 /// \brief Compile a module file for the given module, using the options
846 /// provided by the importing compiler instance. Returns true if the module
847 /// was built without errors.
848 static bool compileModuleImpl(CompilerInstance &ImportingInstance,
849                               SourceLocation ImportLoc,
850                               Module *Module,
851                               StringRef ModuleFileName) {
852   ModuleMap &ModMap
853     = ImportingInstance.getPreprocessor().getHeaderSearchInfo().getModuleMap();
854 
855   // Construct a compiler invocation for creating this module.
856   IntrusiveRefCntPtr<CompilerInvocation> Invocation
857     (new CompilerInvocation(ImportingInstance.getInvocation()));
858 
859   PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
860 
861   // For any options that aren't intended to affect how a module is built,
862   // reset them to their default values.
863   Invocation->getLangOpts()->resetNonModularOptions();
864   PPOpts.resetNonModularOptions();
865 
866   // Remove any macro definitions that are explicitly ignored by the module.
867   // They aren't supposed to affect how the module is built anyway.
868   const HeaderSearchOptions &HSOpts = Invocation->getHeaderSearchOpts();
869   PPOpts.Macros.erase(
870       std::remove_if(PPOpts.Macros.begin(), PPOpts.Macros.end(),
871                      [&HSOpts](const std::pair<std::string, bool> &def) {
872         StringRef MacroDef = def.first;
873         return HSOpts.ModulesIgnoreMacros.count(MacroDef.split('=').first) > 0;
874       }),
875       PPOpts.Macros.end());
876 
877   // Note the name of the module we're building.
878   Invocation->getLangOpts()->CurrentModule = Module->getTopLevelModuleName();
879 
880   // Make sure that the failed-module structure has been allocated in
881   // the importing instance, and propagate the pointer to the newly-created
882   // instance.
883   PreprocessorOptions &ImportingPPOpts
884     = ImportingInstance.getInvocation().getPreprocessorOpts();
885   if (!ImportingPPOpts.FailedModules)
886     ImportingPPOpts.FailedModules = new PreprocessorOptions::FailedModulesSet;
887   PPOpts.FailedModules = ImportingPPOpts.FailedModules;
888 
889   // If there is a module map file, build the module using the module map.
890   // Set up the inputs/outputs so that we build the module from its umbrella
891   // header.
892   FrontendOptions &FrontendOpts = Invocation->getFrontendOpts();
893   FrontendOpts.OutputFile = ModuleFileName.str();
894   FrontendOpts.DisableFree = false;
895   FrontendOpts.GenerateGlobalModuleIndex = false;
896   FrontendOpts.Inputs.clear();
897   InputKind IK = getSourceInputKindFromOptions(*Invocation->getLangOpts());
898 
899   // Don't free the remapped file buffers; they are owned by our caller.
900   PPOpts.RetainRemappedFileBuffers = true;
901 
902   Invocation->getDiagnosticOpts().VerifyDiagnostics = 0;
903   assert(ImportingInstance.getInvocation().getModuleHash() ==
904          Invocation->getModuleHash() && "Module hash mismatch!");
905 
906   // Construct a compiler instance that will be used to actually create the
907   // module.
908   CompilerInstance Instance(/*BuildingModule=*/true);
909   Instance.setInvocation(&*Invocation);
910 
911   Instance.createDiagnostics(new ForwardingDiagnosticConsumer(
912                                    ImportingInstance.getDiagnosticClient()),
913                              /*ShouldOwnClient=*/true);
914 
915   Instance.setVirtualFileSystem(&ImportingInstance.getVirtualFileSystem());
916 
917   // Note that this module is part of the module build stack, so that we
918   // can detect cycles in the module graph.
919   Instance.setFileManager(&ImportingInstance.getFileManager());
920   Instance.createSourceManager(Instance.getFileManager());
921   SourceManager &SourceMgr = Instance.getSourceManager();
922   SourceMgr.setModuleBuildStack(
923     ImportingInstance.getSourceManager().getModuleBuildStack());
924   SourceMgr.pushModuleBuildStack(Module->getTopLevelModuleName(),
925     FullSourceLoc(ImportLoc, ImportingInstance.getSourceManager()));
926 
927   // If we're collecting module dependencies, we need to share a collector
928   // between all of the module CompilerInstances.
929   Instance.setModuleDepCollector(ImportingInstance.getModuleDepCollector());
930 
931   // Get or create the module map that we'll use to build this module.
932   std::string InferredModuleMapContent;
933   if (const FileEntry *ModuleMapFile =
934           ModMap.getContainingModuleMapFile(Module)) {
935     // Use the module map where this module resides.
936     FrontendOpts.Inputs.push_back(
937         FrontendInputFile(ModuleMapFile->getName(), IK));
938   } else {
939     llvm::raw_string_ostream OS(InferredModuleMapContent);
940     Module->print(OS);
941     OS.flush();
942     FrontendOpts.Inputs.push_back(
943         FrontendInputFile("__inferred_module.map", IK));
944 
945     std::unique_ptr<llvm::MemoryBuffer> ModuleMapBuffer =
946         llvm::MemoryBuffer::getMemBuffer(InferredModuleMapContent);
947     ModuleMapFile = Instance.getFileManager().getVirtualFile(
948         "__inferred_module.map", InferredModuleMapContent.size(), 0);
949     SourceMgr.overrideFileContents(ModuleMapFile, std::move(ModuleMapBuffer));
950   }
951 
952   // Construct a module-generating action. Passing through the module map is
953   // safe because the FileManager is shared between the compiler instances.
954   GenerateModuleAction CreateModuleAction(
955       ModMap.getModuleMapFileForUniquing(Module), Module->IsSystem);
956 
957   ImportingInstance.getDiagnostics().Report(ImportLoc,
958                                             diag::remark_module_build)
959     << Module->Name << ModuleFileName;
960 
961   // Execute the action to actually build the module in-place. Use a separate
962   // thread so that we get a stack large enough.
963   const unsigned ThreadStackSize = 8 << 20;
964   llvm::CrashRecoveryContext CRC;
965   CRC.RunSafelyOnThread([&]() { Instance.ExecuteAction(CreateModuleAction); },
966                         ThreadStackSize);
967 
968   ImportingInstance.getDiagnostics().Report(ImportLoc,
969                                             diag::remark_module_build_done)
970     << Module->Name;
971 
972   // Delete the temporary module map file.
973   // FIXME: Even though we're executing under crash protection, it would still
974   // be nice to do this with RemoveFileOnSignal when we can. However, that
975   // doesn't make sense for all clients, so clean this up manually.
976   Instance.clearOutputFiles(/*EraseFiles=*/true);
977 
978   // We've rebuilt a module. If we're allowed to generate or update the global
979   // module index, record that fact in the importing compiler instance.
980   if (ImportingInstance.getFrontendOpts().GenerateGlobalModuleIndex) {
981     ImportingInstance.setBuildGlobalModuleIndex(true);
982   }
983 
984   return !Instance.getDiagnostics().hasErrorOccurred();
985 }
986 
987 static bool compileAndLoadModule(CompilerInstance &ImportingInstance,
988                                  SourceLocation ImportLoc,
989                                  SourceLocation ModuleNameLoc, Module *Module,
990                                  StringRef ModuleFileName) {
991   DiagnosticsEngine &Diags = ImportingInstance.getDiagnostics();
992 
993   auto diagnoseBuildFailure = [&] {
994     Diags.Report(ModuleNameLoc, diag::err_module_not_built)
995         << Module->Name << SourceRange(ImportLoc, ModuleNameLoc);
996   };
997 
998   // FIXME: have LockFileManager return an error_code so that we can
999   // avoid the mkdir when the directory already exists.
1000   StringRef Dir = llvm::sys::path::parent_path(ModuleFileName);
1001   llvm::sys::fs::create_directories(Dir);
1002 
1003   while (1) {
1004     unsigned ModuleLoadCapabilities = ASTReader::ARR_Missing;
1005     llvm::LockFileManager Locked(ModuleFileName);
1006     switch (Locked) {
1007     case llvm::LockFileManager::LFS_Error:
1008       Diags.Report(ModuleNameLoc, diag::err_module_lock_failure)
1009           << Module->Name;
1010       return false;
1011 
1012     case llvm::LockFileManager::LFS_Owned:
1013       // We're responsible for building the module ourselves.
1014       if (!compileModuleImpl(ImportingInstance, ModuleNameLoc, Module,
1015                              ModuleFileName)) {
1016         diagnoseBuildFailure();
1017         return false;
1018       }
1019       break;
1020 
1021     case llvm::LockFileManager::LFS_Shared:
1022       // Someone else is responsible for building the module. Wait for them to
1023       // finish.
1024       if (Locked.waitForUnlock() == llvm::LockFileManager::Res_OwnerDied)
1025         continue; // try again to get the lock.
1026       ModuleLoadCapabilities |= ASTReader::ARR_OutOfDate;
1027       break;
1028     }
1029 
1030     // Try to read the module file, now that we've compiled it.
1031     ASTReader::ASTReadResult ReadResult =
1032         ImportingInstance.getModuleManager()->ReadAST(
1033             ModuleFileName, serialization::MK_ImplicitModule, ImportLoc,
1034             ModuleLoadCapabilities);
1035 
1036     if (ReadResult == ASTReader::OutOfDate &&
1037         Locked == llvm::LockFileManager::LFS_Shared) {
1038       // The module may be out of date in the presence of file system races,
1039       // or if one of its imports depends on header search paths that are not
1040       // consistent with this ImportingInstance.  Try again...
1041       continue;
1042     } else if (ReadResult == ASTReader::Missing) {
1043       diagnoseBuildFailure();
1044     } else if (ReadResult != ASTReader::Success &&
1045                !Diags.hasErrorOccurred()) {
1046       // The ASTReader didn't diagnose the error, so conservatively report it.
1047       diagnoseBuildFailure();
1048     }
1049     return ReadResult == ASTReader::Success;
1050   }
1051 }
1052 
1053 /// \brief Diagnose differences between the current definition of the given
1054 /// configuration macro and the definition provided on the command line.
1055 static void checkConfigMacro(Preprocessor &PP, StringRef ConfigMacro,
1056                              Module *Mod, SourceLocation ImportLoc) {
1057   IdentifierInfo *Id = PP.getIdentifierInfo(ConfigMacro);
1058   SourceManager &SourceMgr = PP.getSourceManager();
1059 
1060   // If this identifier has never had a macro definition, then it could
1061   // not have changed.
1062   if (!Id->hadMacroDefinition())
1063     return;
1064 
1065   // If this identifier does not currently have a macro definition,
1066   // check whether it had one on the command line.
1067   if (!Id->hasMacroDefinition()) {
1068     MacroDirective::DefInfo LatestDef =
1069         PP.getMacroDirectiveHistory(Id)->getDefinition();
1070     for (MacroDirective::DefInfo Def = LatestDef; Def;
1071            Def = Def.getPreviousDefinition()) {
1072       FileID FID = SourceMgr.getFileID(Def.getLocation());
1073       if (FID.isInvalid())
1074         continue;
1075 
1076       // We only care about the predefines buffer.
1077       if (FID != PP.getPredefinesFileID())
1078         continue;
1079 
1080       // This macro was defined on the command line, then #undef'd later.
1081       // Complain.
1082       PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
1083         << true << ConfigMacro << Mod->getFullModuleName();
1084       if (LatestDef.isUndefined())
1085         PP.Diag(LatestDef.getUndefLocation(), diag::note_module_def_undef_here)
1086           << true;
1087       return;
1088     }
1089 
1090     // Okay: no definition in the predefines buffer.
1091     return;
1092   }
1093 
1094   // This identifier has a macro definition. Check whether we had a definition
1095   // on the command line.
1096   MacroDirective::DefInfo LatestDef =
1097       PP.getMacroDirectiveHistory(Id)->getDefinition();
1098   MacroDirective::DefInfo PredefinedDef;
1099   for (MacroDirective::DefInfo Def = LatestDef; Def;
1100          Def = Def.getPreviousDefinition()) {
1101     FileID FID = SourceMgr.getFileID(Def.getLocation());
1102     if (FID.isInvalid())
1103       continue;
1104 
1105     // We only care about the predefines buffer.
1106     if (FID != PP.getPredefinesFileID())
1107       continue;
1108 
1109     PredefinedDef = Def;
1110     break;
1111   }
1112 
1113   // If there was no definition for this macro in the predefines buffer,
1114   // complain.
1115   if (!PredefinedDef ||
1116       (!PredefinedDef.getLocation().isValid() &&
1117        PredefinedDef.getUndefLocation().isValid())) {
1118     PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
1119       << false << ConfigMacro << Mod->getFullModuleName();
1120     PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
1121       << false;
1122     return;
1123   }
1124 
1125   // If the current macro definition is the same as the predefined macro
1126   // definition, it's okay.
1127   if (LatestDef.getMacroInfo() == PredefinedDef.getMacroInfo() ||
1128       LatestDef.getMacroInfo()->isIdenticalTo(*PredefinedDef.getMacroInfo(),PP,
1129                                               /*Syntactically=*/true))
1130     return;
1131 
1132   // The macro definitions differ.
1133   PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
1134     << false << ConfigMacro << Mod->getFullModuleName();
1135   PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
1136     << false;
1137 }
1138 
1139 /// \brief Write a new timestamp file with the given path.
1140 static void writeTimestampFile(StringRef TimestampFile) {
1141   std::error_code EC;
1142   llvm::raw_fd_ostream Out(TimestampFile.str(), EC, llvm::sys::fs::F_None);
1143 }
1144 
1145 /// \brief Prune the module cache of modules that haven't been accessed in
1146 /// a long time.
1147 static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
1148   struct stat StatBuf;
1149   llvm::SmallString<128> TimestampFile;
1150   TimestampFile = HSOpts.ModuleCachePath;
1151   llvm::sys::path::append(TimestampFile, "modules.timestamp");
1152 
1153   // Try to stat() the timestamp file.
1154   if (::stat(TimestampFile.c_str(), &StatBuf)) {
1155     // If the timestamp file wasn't there, create one now.
1156     if (errno == ENOENT) {
1157       writeTimestampFile(TimestampFile);
1158     }
1159     return;
1160   }
1161 
1162   // Check whether the time stamp is older than our pruning interval.
1163   // If not, do nothing.
1164   time_t TimeStampModTime = StatBuf.st_mtime;
1165   time_t CurrentTime = time(nullptr);
1166   if (CurrentTime - TimeStampModTime <= time_t(HSOpts.ModuleCachePruneInterval))
1167     return;
1168 
1169   // Write a new timestamp file so that nobody else attempts to prune.
1170   // There is a benign race condition here, if two Clang instances happen to
1171   // notice at the same time that the timestamp is out-of-date.
1172   writeTimestampFile(TimestampFile);
1173 
1174   // Walk the entire module cache, looking for unused module files and module
1175   // indices.
1176   std::error_code EC;
1177   SmallString<128> ModuleCachePathNative;
1178   llvm::sys::path::native(HSOpts.ModuleCachePath, ModuleCachePathNative);
1179   for (llvm::sys::fs::directory_iterator
1180          Dir(ModuleCachePathNative.str(), EC), DirEnd;
1181        Dir != DirEnd && !EC; Dir.increment(EC)) {
1182     // If we don't have a directory, there's nothing to look into.
1183     if (!llvm::sys::fs::is_directory(Dir->path()))
1184       continue;
1185 
1186     // Walk all of the files within this directory.
1187     for (llvm::sys::fs::directory_iterator File(Dir->path(), EC), FileEnd;
1188          File != FileEnd && !EC; File.increment(EC)) {
1189       // We only care about module and global module index files.
1190       StringRef Extension = llvm::sys::path::extension(File->path());
1191       if (Extension != ".pcm" && Extension != ".timestamp" &&
1192           llvm::sys::path::filename(File->path()) != "modules.idx")
1193         continue;
1194 
1195       // Look at this file. If we can't stat it, there's nothing interesting
1196       // there.
1197       if (::stat(File->path().c_str(), &StatBuf))
1198         continue;
1199 
1200       // If the file has been used recently enough, leave it there.
1201       time_t FileAccessTime = StatBuf.st_atime;
1202       if (CurrentTime - FileAccessTime <=
1203               time_t(HSOpts.ModuleCachePruneAfter)) {
1204         continue;
1205       }
1206 
1207       // Remove the file.
1208       llvm::sys::fs::remove(File->path());
1209 
1210       // Remove the timestamp file.
1211       std::string TimpestampFilename = File->path() + ".timestamp";
1212       llvm::sys::fs::remove(TimpestampFilename);
1213     }
1214 
1215     // If we removed all of the files in the directory, remove the directory
1216     // itself.
1217     if (llvm::sys::fs::directory_iterator(Dir->path(), EC) ==
1218             llvm::sys::fs::directory_iterator() && !EC)
1219       llvm::sys::fs::remove(Dir->path());
1220   }
1221 }
1222 
1223 void CompilerInstance::createModuleManager() {
1224   if (!ModuleManager) {
1225     if (!hasASTContext())
1226       createASTContext();
1227 
1228     // If we're not recursively building a module, check whether we
1229     // need to prune the module cache.
1230     if (getSourceManager().getModuleBuildStack().empty() &&
1231         getHeaderSearchOpts().ModuleCachePruneInterval > 0 &&
1232         getHeaderSearchOpts().ModuleCachePruneAfter > 0) {
1233       pruneModuleCache(getHeaderSearchOpts());
1234     }
1235 
1236     HeaderSearchOptions &HSOpts = getHeaderSearchOpts();
1237     std::string Sysroot = HSOpts.Sysroot;
1238     const PreprocessorOptions &PPOpts = getPreprocessorOpts();
1239     ModuleManager = new ASTReader(getPreprocessor(), *Context,
1240                                   Sysroot.empty() ? "" : Sysroot.c_str(),
1241                                   PPOpts.DisablePCHValidation,
1242                                   /*AllowASTWithCompilerErrors=*/false,
1243                                   /*AllowConfigurationMismatch=*/false,
1244                                   HSOpts.ModulesValidateSystemHeaders,
1245                                   getFrontendOpts().UseGlobalModuleIndex);
1246     if (hasASTConsumer()) {
1247       ModuleManager->setDeserializationListener(
1248         getASTConsumer().GetASTDeserializationListener());
1249       getASTContext().setASTMutationListener(
1250         getASTConsumer().GetASTMutationListener());
1251     }
1252     getASTContext().setExternalSource(ModuleManager);
1253     if (hasSema())
1254       ModuleManager->InitializeSema(getSema());
1255     if (hasASTConsumer())
1256       ModuleManager->StartTranslationUnit(&getASTConsumer());
1257   }
1258 }
1259 
1260 bool CompilerInstance::loadModuleFile(StringRef FileName) {
1261   // Helper to recursively read the module names for all modules we're adding.
1262   // We mark these as known and redirect any attempt to load that module to
1263   // the files we were handed.
1264   struct ReadModuleNames : ASTReaderListener {
1265     CompilerInstance &CI;
1266     std::vector<StringRef> ModuleFileStack;
1267     bool Failed;
1268     bool TopFileIsModule;
1269 
1270     ReadModuleNames(CompilerInstance &CI)
1271         : CI(CI), Failed(false), TopFileIsModule(false) {}
1272 
1273     bool needsImportVisitation() const override { return true; }
1274 
1275     void visitImport(StringRef FileName) override {
1276       ModuleFileStack.push_back(FileName);
1277       if (ASTReader::readASTFileControlBlock(FileName, CI.getFileManager(),
1278                                              *this)) {
1279         CI.getDiagnostics().Report(SourceLocation(),
1280                                    diag::err_module_file_not_found)
1281             << FileName;
1282         // FIXME: Produce a note stack explaining how we got here.
1283         Failed = true;
1284       }
1285       ModuleFileStack.pop_back();
1286     }
1287 
1288     void ReadModuleName(StringRef ModuleName) override {
1289       if (ModuleFileStack.size() == 1)
1290         TopFileIsModule = true;
1291 
1292       auto &ModuleFile = CI.ModuleFileOverrides[ModuleName];
1293       if (!ModuleFile.empty() && ModuleFile != ModuleFileStack.back())
1294         CI.getDiagnostics().Report(SourceLocation(),
1295                                    diag::err_conflicting_module_files)
1296             << ModuleName << ModuleFile << ModuleFileStack.back();
1297       ModuleFile = ModuleFileStack.back();
1298     }
1299   } RMN(*this);
1300 
1301   RMN.visitImport(FileName);
1302 
1303   if (RMN.Failed)
1304     return false;
1305 
1306   // If we never found a module name for the top file, then it's not a module,
1307   // it's a PCH or preamble or something.
1308   if (!RMN.TopFileIsModule) {
1309     getDiagnostics().Report(SourceLocation(), diag::err_module_file_not_module)
1310       << FileName;
1311     return false;
1312   }
1313 
1314   return true;
1315 }
1316 
1317 ModuleLoadResult
1318 CompilerInstance::loadModule(SourceLocation ImportLoc,
1319                              ModuleIdPath Path,
1320                              Module::NameVisibilityKind Visibility,
1321                              bool IsInclusionDirective) {
1322   // Determine what file we're searching from.
1323   StringRef ModuleName = Path[0].first->getName();
1324   SourceLocation ModuleNameLoc = Path[0].second;
1325 
1326   // If we've already handled this import, just return the cached result.
1327   // This one-element cache is important to eliminate redundant diagnostics
1328   // when both the preprocessor and parser see the same import declaration.
1329   if (!ImportLoc.isInvalid() && LastModuleImportLoc == ImportLoc) {
1330     // Make the named module visible.
1331     if (LastModuleImportResult && ModuleName != getLangOpts().CurrentModule &&
1332         ModuleName != getLangOpts().ImplementationOfModule)
1333       ModuleManager->makeModuleVisible(LastModuleImportResult, Visibility,
1334                                        ImportLoc, /*Complain=*/false);
1335     return LastModuleImportResult;
1336   }
1337 
1338   clang::Module *Module = nullptr;
1339 
1340   // If we don't already have information on this module, load the module now.
1341   llvm::DenseMap<const IdentifierInfo *, clang::Module *>::iterator Known
1342     = KnownModules.find(Path[0].first);
1343   if (Known != KnownModules.end()) {
1344     // Retrieve the cached top-level module.
1345     Module = Known->second;
1346   } else if (ModuleName == getLangOpts().CurrentModule ||
1347              ModuleName == getLangOpts().ImplementationOfModule) {
1348     // This is the module we're building.
1349     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
1350     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1351   } else {
1352     // Search for a module with the given name.
1353     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
1354     if (!Module) {
1355       getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_found)
1356       << ModuleName
1357       << SourceRange(ImportLoc, ModuleNameLoc);
1358       ModuleBuildFailed = true;
1359       return ModuleLoadResult();
1360     }
1361 
1362     auto Override = ModuleFileOverrides.find(ModuleName);
1363     bool Explicit = Override != ModuleFileOverrides.end();
1364 
1365     std::string ModuleFileName =
1366         Explicit ? Override->second
1367                  : PP->getHeaderSearchInfo().getModuleFileName(Module);
1368 
1369     // If we don't already have an ASTReader, create one now.
1370     if (!ModuleManager)
1371       createModuleManager();
1372 
1373     if (TheDependencyFileGenerator)
1374       TheDependencyFileGenerator->AttachToASTReader(*ModuleManager);
1375 
1376     if (ModuleDepCollector)
1377       ModuleDepCollector->attachToASTReader(*ModuleManager);
1378 
1379     for (auto &Listener : DependencyCollectors)
1380       Listener->attachToASTReader(*ModuleManager);
1381 
1382     // Try to load the module file.
1383     unsigned ARRFlags =
1384         Explicit ? 0 : ASTReader::ARR_OutOfDate | ASTReader::ARR_Missing;
1385     switch (ModuleManager->ReadAST(ModuleFileName,
1386                                    Explicit ? serialization::MK_ExplicitModule
1387                                             : serialization::MK_ImplicitModule,
1388                                    ImportLoc, ARRFlags)) {
1389     case ASTReader::Success:
1390       break;
1391 
1392     case ASTReader::OutOfDate:
1393     case ASTReader::Missing: {
1394       if (Explicit) {
1395         // ReadAST has already complained for us.
1396         ModuleLoader::HadFatalFailure = true;
1397         KnownModules[Path[0].first] = nullptr;
1398         return ModuleLoadResult();
1399       }
1400 
1401       // The module file is missing or out-of-date. Build it.
1402       assert(Module && "missing module file");
1403       // Check whether there is a cycle in the module graph.
1404       ModuleBuildStack ModPath = getSourceManager().getModuleBuildStack();
1405       ModuleBuildStack::iterator Pos = ModPath.begin(), PosEnd = ModPath.end();
1406       for (; Pos != PosEnd; ++Pos) {
1407         if (Pos->first == ModuleName)
1408           break;
1409       }
1410 
1411       if (Pos != PosEnd) {
1412         SmallString<256> CyclePath;
1413         for (; Pos != PosEnd; ++Pos) {
1414           CyclePath += Pos->first;
1415           CyclePath += " -> ";
1416         }
1417         CyclePath += ModuleName;
1418 
1419         getDiagnostics().Report(ModuleNameLoc, diag::err_module_cycle)
1420           << ModuleName << CyclePath;
1421         return ModuleLoadResult();
1422       }
1423 
1424       // Check whether we have already attempted to build this module (but
1425       // failed).
1426       if (getPreprocessorOpts().FailedModules &&
1427           getPreprocessorOpts().FailedModules->hasAlreadyFailed(ModuleName)) {
1428         getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_built)
1429           << ModuleName
1430           << SourceRange(ImportLoc, ModuleNameLoc);
1431         ModuleBuildFailed = true;
1432         return ModuleLoadResult();
1433       }
1434 
1435       // Try to compile and then load the module.
1436       if (!compileAndLoadModule(*this, ImportLoc, ModuleNameLoc, Module,
1437                                 ModuleFileName)) {
1438         assert(getDiagnostics().hasErrorOccurred() &&
1439                "undiagnosed error in compileAndLoadModule");
1440         if (getPreprocessorOpts().FailedModules)
1441           getPreprocessorOpts().FailedModules->addFailed(ModuleName);
1442         KnownModules[Path[0].first] = nullptr;
1443         ModuleBuildFailed = true;
1444         return ModuleLoadResult();
1445       }
1446 
1447       // Okay, we've rebuilt and now loaded the module.
1448       break;
1449     }
1450 
1451     case ASTReader::VersionMismatch:
1452     case ASTReader::ConfigurationMismatch:
1453     case ASTReader::HadErrors:
1454       ModuleLoader::HadFatalFailure = true;
1455       // FIXME: The ASTReader will already have complained, but can we showhorn
1456       // that diagnostic information into a more useful form?
1457       KnownModules[Path[0].first] = nullptr;
1458       return ModuleLoadResult();
1459 
1460     case ASTReader::Failure:
1461       ModuleLoader::HadFatalFailure = true;
1462       // Already complained, but note now that we failed.
1463       KnownModules[Path[0].first] = nullptr;
1464       ModuleBuildFailed = true;
1465       return ModuleLoadResult();
1466     }
1467 
1468     // Cache the result of this top-level module lookup for later.
1469     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1470   }
1471 
1472   // If we never found the module, fail.
1473   if (!Module)
1474     return ModuleLoadResult();
1475 
1476   // Verify that the rest of the module path actually corresponds to
1477   // a submodule.
1478   if (Path.size() > 1) {
1479     for (unsigned I = 1, N = Path.size(); I != N; ++I) {
1480       StringRef Name = Path[I].first->getName();
1481       clang::Module *Sub = Module->findSubmodule(Name);
1482 
1483       if (!Sub) {
1484         // Attempt to perform typo correction to find a module name that works.
1485         SmallVector<StringRef, 2> Best;
1486         unsigned BestEditDistance = (std::numeric_limits<unsigned>::max)();
1487 
1488         for (clang::Module::submodule_iterator J = Module->submodule_begin(),
1489                                             JEnd = Module->submodule_end();
1490              J != JEnd; ++J) {
1491           unsigned ED = Name.edit_distance((*J)->Name,
1492                                            /*AllowReplacements=*/true,
1493                                            BestEditDistance);
1494           if (ED <= BestEditDistance) {
1495             if (ED < BestEditDistance) {
1496               Best.clear();
1497               BestEditDistance = ED;
1498             }
1499 
1500             Best.push_back((*J)->Name);
1501           }
1502         }
1503 
1504         // If there was a clear winner, user it.
1505         if (Best.size() == 1) {
1506           getDiagnostics().Report(Path[I].second,
1507                                   diag::err_no_submodule_suggest)
1508             << Path[I].first << Module->getFullModuleName() << Best[0]
1509             << SourceRange(Path[0].second, Path[I-1].second)
1510             << FixItHint::CreateReplacement(SourceRange(Path[I].second),
1511                                             Best[0]);
1512 
1513           Sub = Module->findSubmodule(Best[0]);
1514         }
1515       }
1516 
1517       if (!Sub) {
1518         // No submodule by this name. Complain, and don't look for further
1519         // submodules.
1520         getDiagnostics().Report(Path[I].second, diag::err_no_submodule)
1521           << Path[I].first << Module->getFullModuleName()
1522           << SourceRange(Path[0].second, Path[I-1].second);
1523         break;
1524       }
1525 
1526       Module = Sub;
1527     }
1528   }
1529 
1530   // Don't make the module visible if we are in the implementation.
1531   if (ModuleName == getLangOpts().ImplementationOfModule)
1532     return ModuleLoadResult(Module, false);
1533 
1534   // Make the named module visible, if it's not already part of the module
1535   // we are parsing.
1536   if (ModuleName != getLangOpts().CurrentModule) {
1537     if (!Module->IsFromModuleFile) {
1538       // We have an umbrella header or directory that doesn't actually include
1539       // all of the headers within the directory it covers. Complain about
1540       // this missing submodule and recover by forgetting that we ever saw
1541       // this submodule.
1542       // FIXME: Should we detect this at module load time? It seems fairly
1543       // expensive (and rare).
1544       getDiagnostics().Report(ImportLoc, diag::warn_missing_submodule)
1545         << Module->getFullModuleName()
1546         << SourceRange(Path.front().second, Path.back().second);
1547 
1548       return ModuleLoadResult(nullptr, true);
1549     }
1550 
1551     // Check whether this module is available.
1552     clang::Module::Requirement Requirement;
1553     clang::Module::HeaderDirective MissingHeader;
1554     if (!Module->isAvailable(getLangOpts(), getTarget(), Requirement,
1555                              MissingHeader)) {
1556       if (MissingHeader.FileNameLoc.isValid()) {
1557         getDiagnostics().Report(MissingHeader.FileNameLoc,
1558                                 diag::err_module_header_missing)
1559           << MissingHeader.IsUmbrella << MissingHeader.FileName;
1560       } else {
1561         getDiagnostics().Report(ImportLoc, diag::err_module_unavailable)
1562           << Module->getFullModuleName()
1563           << Requirement.second << Requirement.first
1564           << SourceRange(Path.front().second, Path.back().second);
1565       }
1566       LastModuleImportLoc = ImportLoc;
1567       LastModuleImportResult = ModuleLoadResult();
1568       return ModuleLoadResult();
1569     }
1570 
1571     ModuleManager->makeModuleVisible(Module, Visibility, ImportLoc,
1572                                      /*Complain=*/true);
1573   }
1574 
1575   // Check for any configuration macros that have changed.
1576   clang::Module *TopModule = Module->getTopLevelModule();
1577   for (unsigned I = 0, N = TopModule->ConfigMacros.size(); I != N; ++I) {
1578     checkConfigMacro(getPreprocessor(), TopModule->ConfigMacros[I],
1579                      Module, ImportLoc);
1580   }
1581 
1582   // If this module import was due to an inclusion directive, create an
1583   // implicit import declaration to capture it in the AST.
1584   if (IsInclusionDirective && hasASTContext()) {
1585     TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
1586     ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
1587                                                      ImportLoc, Module,
1588                                                      Path.back().second);
1589     TU->addDecl(ImportD);
1590     if (Consumer)
1591       Consumer->HandleImplicitImportDecl(ImportD);
1592   }
1593 
1594   LastModuleImportLoc = ImportLoc;
1595   LastModuleImportResult = ModuleLoadResult(Module, false);
1596   return LastModuleImportResult;
1597 }
1598 
1599 void CompilerInstance::makeModuleVisible(Module *Mod,
1600                                          Module::NameVisibilityKind Visibility,
1601                                          SourceLocation ImportLoc,
1602                                          bool Complain){
1603   ModuleManager->makeModuleVisible(Mod, Visibility, ImportLoc, Complain);
1604 }
1605 
1606 GlobalModuleIndex *CompilerInstance::loadGlobalModuleIndex(
1607     SourceLocation TriggerLoc) {
1608   if (!ModuleManager)
1609     createModuleManager();
1610   // Can't do anything if we don't have the module manager.
1611   if (!ModuleManager)
1612     return nullptr;
1613   // Get an existing global index.  This loads it if not already
1614   // loaded.
1615   ModuleManager->loadGlobalIndex();
1616   GlobalModuleIndex *GlobalIndex = ModuleManager->getGlobalIndex();
1617   // If the global index doesn't exist, create it.
1618   if (!GlobalIndex && shouldBuildGlobalModuleIndex() && hasFileManager() &&
1619       hasPreprocessor()) {
1620     llvm::sys::fs::create_directories(
1621       getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
1622     GlobalModuleIndex::writeIndex(
1623       getFileManager(),
1624       getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
1625     ModuleManager->resetForReload();
1626     ModuleManager->loadGlobalIndex();
1627     GlobalIndex = ModuleManager->getGlobalIndex();
1628   }
1629   // For finding modules needing to be imported for fixit messages,
1630   // we need to make the global index cover all modules, so we do that here.
1631   if (!HaveFullGlobalModuleIndex && GlobalIndex && !buildingModule()) {
1632     ModuleMap &MMap = getPreprocessor().getHeaderSearchInfo().getModuleMap();
1633     bool RecreateIndex = false;
1634     for (ModuleMap::module_iterator I = MMap.module_begin(),
1635         E = MMap.module_end(); I != E; ++I) {
1636       Module *TheModule = I->second;
1637       const FileEntry *Entry = TheModule->getASTFile();
1638       if (!Entry) {
1639         SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 2> Path;
1640         Path.push_back(std::make_pair(
1641 				  getPreprocessor().getIdentifierInfo(TheModule->Name), TriggerLoc));
1642         std::reverse(Path.begin(), Path.end());
1643 		    // Load a module as hidden.  This also adds it to the global index.
1644         loadModule(TheModule->DefinitionLoc, Path,
1645                                              Module::Hidden, false);
1646         RecreateIndex = true;
1647       }
1648     }
1649     if (RecreateIndex) {
1650       GlobalModuleIndex::writeIndex(
1651         getFileManager(),
1652         getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
1653       ModuleManager->resetForReload();
1654       ModuleManager->loadGlobalIndex();
1655       GlobalIndex = ModuleManager->getGlobalIndex();
1656     }
1657     HaveFullGlobalModuleIndex = true;
1658   }
1659   return GlobalIndex;
1660 }
1661 
1662 // Check global module index for missing imports.
1663 bool
1664 CompilerInstance::lookupMissingImports(StringRef Name,
1665                                        SourceLocation TriggerLoc) {
1666   // Look for the symbol in non-imported modules, but only if an error
1667   // actually occurred.
1668   if (!buildingModule()) {
1669     // Load global module index, or retrieve a previously loaded one.
1670     GlobalModuleIndex *GlobalIndex = loadGlobalModuleIndex(
1671       TriggerLoc);
1672 
1673     // Only if we have a global index.
1674     if (GlobalIndex) {
1675       GlobalModuleIndex::HitSet FoundModules;
1676 
1677       // Find the modules that reference the identifier.
1678       // Note that this only finds top-level modules.
1679       // We'll let diagnoseTypo find the actual declaration module.
1680       if (GlobalIndex->lookupIdentifier(Name, FoundModules))
1681         return true;
1682     }
1683   }
1684 
1685   return false;
1686 }
1687 void CompilerInstance::resetAndLeakSema() { BuryPointer(takeSema()); }
1688