xref: /llvm-project/clang/lib/Frontend/CompilerInstance.cpp (revision 6153581a40f672000399bff17aa70bfb727da04c)
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::string ErrorInfo;
138   bool OwnsStream = false;
139   raw_ostream *OS = &llvm::errs();
140   if (DiagOpts->DiagnosticLogFile != "-") {
141     // Create the output stream.
142     llvm::raw_fd_ostream *FileOS(new llvm::raw_fd_ostream(
143         DiagOpts->DiagnosticLogFile.c_str(), ErrorInfo,
144         llvm::sys::fs::F_Append | llvm::sys::fs::F_Text));
145     if (!ErrorInfo.empty()) {
146       Diags.Report(diag::warn_fe_cc_log_diagnostics_failure)
147         << DiagOpts->DiagnosticLogFile << ErrorInfo;
148     } else {
149       FileOS->SetUnbuffered();
150       FileOS->SetUseAtomicWrites(true);
151       OS = FileOS;
152       OwnsStream = true;
153     }
154   }
155 
156   // Chain in the diagnostic client which will log the diagnostics.
157   LogDiagnosticPrinter *Logger = new LogDiagnosticPrinter(*OS, DiagOpts,
158                                                           OwnsStream);
159   if (CodeGenOpts)
160     Logger->setDwarfDebugFlags(CodeGenOpts->DwarfDebugFlags);
161   Diags.setClient(new ChainedDiagnosticConsumer(Diags.takeClient(), Logger));
162 }
163 
164 static void SetupSerializedDiagnostics(DiagnosticOptions *DiagOpts,
165                                        DiagnosticsEngine &Diags,
166                                        StringRef OutputFile) {
167   std::string ErrorInfo;
168   std::unique_ptr<llvm::raw_fd_ostream> OS;
169   OS.reset(new llvm::raw_fd_ostream(OutputFile.str().c_str(), ErrorInfo,
170                                     llvm::sys::fs::F_None));
171 
172   if (!ErrorInfo.empty()) {
173     Diags.Report(diag::warn_fe_serialized_diag_failure)
174       << OutputFile << ErrorInfo;
175     return;
176   }
177 
178   DiagnosticConsumer *SerializedConsumer =
179       clang::serialized_diags::create(OS.release(), DiagOpts);
180 
181   Diags.setClient(new ChainedDiagnosticConsumer(Diags.takeClient(),
182                                                 SerializedConsumer));
183 }
184 
185 void CompilerInstance::createDiagnostics(DiagnosticConsumer *Client,
186                                          bool ShouldOwnClient) {
187   Diagnostics = createDiagnostics(&getDiagnosticOpts(), Client,
188                                   ShouldOwnClient, &getCodeGenOpts());
189 }
190 
191 IntrusiveRefCntPtr<DiagnosticsEngine>
192 CompilerInstance::createDiagnostics(DiagnosticOptions *Opts,
193                                     DiagnosticConsumer *Client,
194                                     bool ShouldOwnClient,
195                                     const CodeGenOptions *CodeGenOpts) {
196   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
197   IntrusiveRefCntPtr<DiagnosticsEngine>
198       Diags(new DiagnosticsEngine(DiagID, Opts));
199 
200   // Create the diagnostic client for reporting errors or for
201   // implementing -verify.
202   if (Client) {
203     Diags->setClient(Client, ShouldOwnClient);
204   } else
205     Diags->setClient(new TextDiagnosticPrinter(llvm::errs(), Opts));
206 
207   // Chain in -verify checker, if requested.
208   if (Opts->VerifyDiagnostics)
209     Diags->setClient(new VerifyDiagnosticConsumer(*Diags));
210 
211   // Chain in -diagnostic-log-file dumper, if requested.
212   if (!Opts->DiagnosticLogFile.empty())
213     SetUpDiagnosticLog(Opts, CodeGenOpts, *Diags);
214 
215   if (!Opts->DiagnosticSerializationFile.empty())
216     SetupSerializedDiagnostics(Opts, *Diags,
217                                Opts->DiagnosticSerializationFile);
218 
219   // Configure our handling of diagnostics.
220   ProcessWarningOptions(*Diags, *Opts);
221 
222   return Diags;
223 }
224 
225 // File Manager
226 
227 void CompilerInstance::createFileManager() {
228   if (!hasVirtualFileSystem()) {
229     // TODO: choose the virtual file system based on the CompilerInvocation.
230     setVirtualFileSystem(vfs::getRealFileSystem());
231   }
232   FileMgr = new FileManager(getFileSystemOpts(), VirtualFileSystem);
233 }
234 
235 // Source Manager
236 
237 void CompilerInstance::createSourceManager(FileManager &FileMgr) {
238   SourceMgr = new SourceManager(getDiagnostics(), FileMgr);
239 }
240 
241 // Initialize the remapping of files to alternative contents, e.g.,
242 // those specified through other files.
243 static void InitializeFileRemapping(DiagnosticsEngine &Diags,
244                                     SourceManager &SourceMgr,
245                                     FileManager &FileMgr,
246                                     const PreprocessorOptions &InitOpts) {
247   // Remap files in the source manager (with buffers).
248   for (const auto &RB : InitOpts.RemappedFileBuffers) {
249     // Create the file entry for the file that we're mapping from.
250     const FileEntry *FromFile =
251         FileMgr.getVirtualFile(RB.first, RB.second->getBufferSize(), 0);
252     if (!FromFile) {
253       Diags.Report(diag::err_fe_remap_missing_from_file) << RB.first;
254       if (!InitOpts.RetainRemappedFileBuffers)
255         delete RB.second;
256       continue;
257     }
258 
259     // Override the contents of the "from" file with the contents of
260     // the "to" file.
261     SourceMgr.overrideFileContents(FromFile, RB.second,
262                                    InitOpts.RetainRemappedFileBuffers);
263   }
264 
265   // Remap files in the source manager (with other files).
266   for (const auto &RF : InitOpts.RemappedFiles) {
267     // Find the file that we're mapping to.
268     const FileEntry *ToFile = FileMgr.getFile(RF.second);
269     if (!ToFile) {
270       Diags.Report(diag::err_fe_remap_missing_to_file) << RF.first << RF.second;
271       continue;
272     }
273 
274     // Create the file entry for the file that we're mapping from.
275     const FileEntry *FromFile =
276         FileMgr.getVirtualFile(RF.first, ToFile->getSize(), 0);
277     if (!FromFile) {
278       Diags.Report(diag::err_fe_remap_missing_from_file) << RF.first;
279       continue;
280     }
281 
282     // Override the contents of the "from" file with the contents of
283     // the "to" file.
284     SourceMgr.overrideFileContents(FromFile, ToFile);
285   }
286 
287   SourceMgr.setOverridenFilesKeepOriginalName(
288       InitOpts.RemappedFilesKeepOriginalName);
289 }
290 
291 // Preprocessor
292 
293 void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
294   const PreprocessorOptions &PPOpts = getPreprocessorOpts();
295 
296   // Create a PTH manager if we are using some form of a token cache.
297   PTHManager *PTHMgr = nullptr;
298   if (!PPOpts.TokenCache.empty())
299     PTHMgr = PTHManager::Create(PPOpts.TokenCache, getDiagnostics());
300 
301   // Create the Preprocessor.
302   HeaderSearch *HeaderInfo = new HeaderSearch(&getHeaderSearchOpts(),
303                                               getSourceManager(),
304                                               getDiagnostics(),
305                                               getLangOpts(),
306                                               &getTarget());
307   PP = new Preprocessor(&getPreprocessorOpts(), getDiagnostics(), getLangOpts(),
308                         getSourceManager(), *HeaderInfo, *this, PTHMgr,
309                         /*OwnsHeaderSearch=*/true, TUKind);
310   PP->Initialize(getTarget());
311 
312   // Note that this is different then passing PTHMgr to Preprocessor's ctor.
313   // That argument is used as the IdentifierInfoLookup argument to
314   // IdentifierTable's ctor.
315   if (PTHMgr) {
316     PTHMgr->setPreprocessor(&*PP);
317     PP->setPTHManager(PTHMgr);
318   }
319 
320   if (PPOpts.DetailedRecord)
321     PP->createPreprocessingRecord();
322 
323   // Apply remappings to the source manager.
324   InitializeFileRemapping(PP->getDiagnostics(), PP->getSourceManager(),
325                           PP->getFileManager(), PPOpts);
326 
327   // Predefine macros and configure the preprocessor.
328   InitializePreprocessor(*PP, PPOpts, getFrontendOpts());
329 
330   // Initialize the header search object.
331   ApplyHeaderSearchOptions(PP->getHeaderSearchInfo(), getHeaderSearchOpts(),
332                            PP->getLangOpts(), PP->getTargetInfo().getTriple());
333 
334   PP->setPreprocessedOutput(getPreprocessorOutputOpts().ShowCPP);
335 
336   // Set up the module path, including the hash for the
337   // module-creation options.
338   SmallString<256> SpecificModuleCache(
339                            getHeaderSearchOpts().ModuleCachePath);
340   if (!getHeaderSearchOpts().DisableModuleHash)
341     llvm::sys::path::append(SpecificModuleCache,
342                             getInvocation().getModuleHash());
343   PP->getHeaderSearchInfo().setModuleCachePath(SpecificModuleCache);
344 
345   // Handle generating dependencies, if requested.
346   const DependencyOutputOptions &DepOpts = getDependencyOutputOpts();
347   if (!DepOpts.OutputFile.empty())
348     TheDependencyFileGenerator.reset(
349         DependencyFileGenerator::CreateAndAttachToPreprocessor(*PP, DepOpts));
350   if (!DepOpts.DOTOutputFile.empty())
351     AttachDependencyGraphGen(*PP, DepOpts.DOTOutputFile,
352                              getHeaderSearchOpts().Sysroot);
353 
354   for (auto &Listener : DependencyCollectors)
355     Listener->attachToPreprocessor(*PP);
356 
357   // If we don't have a collector, but we are collecting module dependencies,
358   // then we're the top level compiler instance and need to create one.
359   if (!ModuleDepCollector && !DepOpts.ModuleDependencyOutputDir.empty())
360     ModuleDepCollector = std::make_shared<ModuleDependencyCollector>(
361         DepOpts.ModuleDependencyOutputDir);
362 
363   // Handle generating header include information, if requested.
364   if (DepOpts.ShowHeaderIncludes)
365     AttachHeaderIncludeGen(*PP);
366   if (!DepOpts.HeaderIncludeOutputFile.empty()) {
367     StringRef OutputPath = DepOpts.HeaderIncludeOutputFile;
368     if (OutputPath == "-")
369       OutputPath = "";
370     AttachHeaderIncludeGen(*PP, /*ShowAllHeaders=*/true, OutputPath,
371                            /*ShowDepth=*/false);
372   }
373 
374   if (DepOpts.PrintShowIncludes) {
375     AttachHeaderIncludeGen(*PP, /*ShowAllHeaders=*/false, /*OutputPath=*/"",
376                            /*ShowDepth=*/true, /*MSStyle=*/true);
377   }
378 }
379 
380 // ASTContext
381 
382 void CompilerInstance::createASTContext() {
383   Preprocessor &PP = getPreprocessor();
384   Context = new ASTContext(getLangOpts(), PP.getSourceManager(),
385                            PP.getIdentifierTable(), PP.getSelectorTable(),
386                            PP.getBuiltinInfo());
387   Context->InitBuiltinTypes(getTarget());
388 }
389 
390 // ExternalASTSource
391 
392 void CompilerInstance::createPCHExternalASTSource(
393     StringRef Path, bool DisablePCHValidation, bool AllowPCHWithCompilerErrors,
394     void *DeserializationListener, bool OwnDeserializationListener) {
395   IntrusiveRefCntPtr<ExternalASTSource> Source;
396   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
397   Source = createPCHExternalASTSource(
398       Path, getHeaderSearchOpts().Sysroot, DisablePCHValidation,
399       AllowPCHWithCompilerErrors, getPreprocessor(), getASTContext(),
400       DeserializationListener, OwnDeserializationListener, Preamble,
401       getFrontendOpts().UseGlobalModuleIndex);
402   ModuleManager = static_cast<ASTReader*>(Source.get());
403   getASTContext().setExternalSource(Source);
404 }
405 
406 ExternalASTSource *CompilerInstance::createPCHExternalASTSource(
407     StringRef Path, const std::string &Sysroot, bool DisablePCHValidation,
408     bool AllowPCHWithCompilerErrors, Preprocessor &PP, ASTContext &Context,
409     void *DeserializationListener, bool OwnDeserializationListener,
410     bool Preamble, bool UseGlobalModuleIndex) {
411   HeaderSearchOptions &HSOpts = PP.getHeaderSearchInfo().getHeaderSearchOpts();
412 
413   std::unique_ptr<ASTReader> Reader;
414   Reader.reset(new ASTReader(PP, Context,
415                              Sysroot.empty() ? "" : Sysroot.c_str(),
416                              DisablePCHValidation,
417                              AllowPCHWithCompilerErrors,
418                              /*AllowConfigurationMismatch*/false,
419                              HSOpts.ModulesValidateSystemHeaders,
420                              UseGlobalModuleIndex));
421 
422   Reader->setDeserializationListener(
423       static_cast<ASTDeserializationListener *>(DeserializationListener),
424       /*TakeOwnership=*/OwnDeserializationListener);
425   switch (Reader->ReadAST(Path,
426                           Preamble ? serialization::MK_Preamble
427                                    : serialization::MK_PCH,
428                           SourceLocation(),
429                           ASTReader::ARR_None)) {
430   case ASTReader::Success:
431     // Set the predefines buffer as suggested by the PCH reader. Typically, the
432     // predefines buffer will be empty.
433     PP.setPredefines(Reader->getSuggestedPredefines());
434     return Reader.release();
435 
436   case ASTReader::Failure:
437     // Unrecoverable failure: don't even try to process the input file.
438     break;
439 
440   case ASTReader::Missing:
441   case ASTReader::OutOfDate:
442   case ASTReader::VersionMismatch:
443   case ASTReader::ConfigurationMismatch:
444   case ASTReader::HadErrors:
445     // No suitable PCH file could be found. Return an error.
446     break;
447   }
448 
449   return nullptr;
450 }
451 
452 // Code Completion
453 
454 static bool EnableCodeCompletion(Preprocessor &PP,
455                                  const std::string &Filename,
456                                  unsigned Line,
457                                  unsigned Column) {
458   // Tell the source manager to chop off the given file at a specific
459   // line and column.
460   const FileEntry *Entry = PP.getFileManager().getFile(Filename);
461   if (!Entry) {
462     PP.getDiagnostics().Report(diag::err_fe_invalid_code_complete_file)
463       << Filename;
464     return true;
465   }
466 
467   // Truncate the named file at the given line/column.
468   PP.SetCodeCompletionPoint(Entry, Line, Column);
469   return false;
470 }
471 
472 void CompilerInstance::createCodeCompletionConsumer() {
473   const ParsedSourceLocation &Loc = getFrontendOpts().CodeCompletionAt;
474   if (!CompletionConsumer) {
475     setCodeCompletionConsumer(
476       createCodeCompletionConsumer(getPreprocessor(),
477                                    Loc.FileName, Loc.Line, Loc.Column,
478                                    getFrontendOpts().CodeCompleteOpts,
479                                    llvm::outs()));
480     if (!CompletionConsumer)
481       return;
482   } else if (EnableCodeCompletion(getPreprocessor(), Loc.FileName,
483                                   Loc.Line, Loc.Column)) {
484     setCodeCompletionConsumer(nullptr);
485     return;
486   }
487 
488   if (CompletionConsumer->isOutputBinary() &&
489       llvm::sys::ChangeStdoutToBinary()) {
490     getPreprocessor().getDiagnostics().Report(diag::err_fe_stdout_binary);
491     setCodeCompletionConsumer(nullptr);
492   }
493 }
494 
495 void CompilerInstance::createFrontendTimer() {
496   FrontendTimer.reset(new llvm::Timer("Clang front-end timer"));
497 }
498 
499 CodeCompleteConsumer *
500 CompilerInstance::createCodeCompletionConsumer(Preprocessor &PP,
501                                                const std::string &Filename,
502                                                unsigned Line,
503                                                unsigned Column,
504                                                const CodeCompleteOptions &Opts,
505                                                raw_ostream &OS) {
506   if (EnableCodeCompletion(PP, Filename, Line, Column))
507     return nullptr;
508 
509   // Set up the creation routine for code-completion.
510   return new PrintingCodeCompleteConsumer(Opts, OS);
511 }
512 
513 void CompilerInstance::createSema(TranslationUnitKind TUKind,
514                                   CodeCompleteConsumer *CompletionConsumer) {
515   TheSema.reset(new Sema(getPreprocessor(), getASTContext(), getASTConsumer(),
516                          TUKind, CompletionConsumer));
517 }
518 
519 // Output Files
520 
521 void CompilerInstance::addOutputFile(const OutputFile &OutFile) {
522   assert(OutFile.OS && "Attempt to add empty stream to output list!");
523   OutputFiles.push_back(OutFile);
524 }
525 
526 void CompilerInstance::clearOutputFiles(bool EraseFiles) {
527   for (std::list<OutputFile>::iterator
528          it = OutputFiles.begin(), ie = OutputFiles.end(); it != ie; ++it) {
529     delete it->OS;
530     if (!it->TempFilename.empty()) {
531       if (EraseFiles) {
532         llvm::sys::fs::remove(it->TempFilename);
533       } else {
534         SmallString<128> NewOutFile(it->Filename);
535 
536         // If '-working-directory' was passed, the output filename should be
537         // relative to that.
538         FileMgr->FixupRelativePath(NewOutFile);
539         if (std::error_code ec =
540                 llvm::sys::fs::rename(it->TempFilename, NewOutFile.str())) {
541           getDiagnostics().Report(diag::err_unable_to_rename_temp)
542             << it->TempFilename << it->Filename << ec.message();
543 
544           llvm::sys::fs::remove(it->TempFilename);
545         }
546       }
547     } else if (!it->Filename.empty() && EraseFiles)
548       llvm::sys::fs::remove(it->Filename);
549 
550   }
551   OutputFiles.clear();
552 }
553 
554 llvm::raw_fd_ostream *
555 CompilerInstance::createDefaultOutputFile(bool Binary,
556                                           StringRef InFile,
557                                           StringRef Extension) {
558   return createOutputFile(getFrontendOpts().OutputFile, Binary,
559                           /*RemoveFileOnSignal=*/true, InFile, Extension,
560                           /*UseTemporary=*/true);
561 }
562 
563 llvm::raw_null_ostream *CompilerInstance::createNullOutputFile() {
564   llvm::raw_null_ostream *OS = new llvm::raw_null_ostream();
565   addOutputFile(OutputFile("", "", OS));
566   return OS;
567 }
568 
569 llvm::raw_fd_ostream *
570 CompilerInstance::createOutputFile(StringRef OutputPath,
571                                    bool Binary, bool RemoveFileOnSignal,
572                                    StringRef InFile,
573                                    StringRef Extension,
574                                    bool UseTemporary,
575                                    bool CreateMissingDirectories) {
576   std::string Error, OutputPathName, TempPathName;
577   llvm::raw_fd_ostream *OS = createOutputFile(OutputPath, Error, Binary,
578                                               RemoveFileOnSignal,
579                                               InFile, Extension,
580                                               UseTemporary,
581                                               CreateMissingDirectories,
582                                               &OutputPathName,
583                                               &TempPathName);
584   if (!OS) {
585     getDiagnostics().Report(diag::err_fe_unable_to_open_output)
586       << OutputPath << Error;
587     return nullptr;
588   }
589 
590   // Add the output file -- but don't try to remove "-", since this means we are
591   // using stdin.
592   addOutputFile(OutputFile((OutputPathName != "-") ? OutputPathName : "",
593                 TempPathName, OS));
594 
595   return OS;
596 }
597 
598 llvm::raw_fd_ostream *
599 CompilerInstance::createOutputFile(StringRef OutputPath,
600                                    std::string &Error,
601                                    bool Binary,
602                                    bool RemoveFileOnSignal,
603                                    StringRef InFile,
604                                    StringRef Extension,
605                                    bool UseTemporary,
606                                    bool CreateMissingDirectories,
607                                    std::string *ResultPathName,
608                                    std::string *TempPathName) {
609   assert((!CreateMissingDirectories || UseTemporary) &&
610          "CreateMissingDirectories is only allowed when using temporary files");
611 
612   std::string OutFile, TempFile;
613   if (!OutputPath.empty()) {
614     OutFile = OutputPath;
615   } else if (InFile == "-") {
616     OutFile = "-";
617   } else if (!Extension.empty()) {
618     SmallString<128> Path(InFile);
619     llvm::sys::path::replace_extension(Path, Extension);
620     OutFile = Path.str();
621   } else {
622     OutFile = "-";
623   }
624 
625   std::unique_ptr<llvm::raw_fd_ostream> OS;
626   std::string OSFile;
627 
628   if (UseTemporary) {
629     if (OutFile == "-")
630       UseTemporary = false;
631     else {
632       llvm::sys::fs::file_status Status;
633       llvm::sys::fs::status(OutputPath, Status);
634       if (llvm::sys::fs::exists(Status)) {
635         // Fail early if we can't write to the final destination.
636         if (!llvm::sys::fs::can_write(OutputPath))
637           return nullptr;
638 
639         // Don't use a temporary if the output is a special file. This handles
640         // things like '-o /dev/null'
641         if (!llvm::sys::fs::is_regular_file(Status))
642           UseTemporary = false;
643       }
644     }
645   }
646 
647   if (UseTemporary) {
648     // Create a temporary file.
649     SmallString<128> TempPath;
650     TempPath = OutFile;
651     TempPath += "-%%%%%%%%";
652     int fd;
653     std::error_code EC =
654         llvm::sys::fs::createUniqueFile(TempPath.str(), fd, TempPath);
655 
656     if (CreateMissingDirectories &&
657         EC == llvm::errc::no_such_file_or_directory) {
658       StringRef Parent = llvm::sys::path::parent_path(OutputPath);
659       EC = llvm::sys::fs::create_directories(Parent);
660       if (!EC) {
661         EC = llvm::sys::fs::createUniqueFile(TempPath.str(), fd, TempPath);
662       }
663     }
664 
665     if (!EC) {
666       OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
667       OSFile = TempFile = TempPath.str();
668     }
669     // If we failed to create the temporary, fallback to writing to the file
670     // directly. This handles the corner case where we cannot write to the
671     // directory, but can write to the file.
672   }
673 
674   if (!OS) {
675     OSFile = OutFile;
676     OS.reset(new llvm::raw_fd_ostream(
677         OSFile.c_str(), Error,
678         (Binary ? llvm::sys::fs::F_None : llvm::sys::fs::F_Text)));
679     if (!Error.empty())
680       return nullptr;
681   }
682 
683   // Make sure the out stream file gets removed if we crash.
684   if (RemoveFileOnSignal)
685     llvm::sys::RemoveFileOnSignal(OSFile);
686 
687   if (ResultPathName)
688     *ResultPathName = OutFile;
689   if (TempPathName)
690     *TempPathName = TempFile;
691 
692   return OS.release();
693 }
694 
695 // Initialization Utilities
696 
697 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input){
698   return InitializeSourceManager(Input, getDiagnostics(),
699                                  getFileManager(), getSourceManager(),
700                                  getFrontendOpts());
701 }
702 
703 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input,
704                                                DiagnosticsEngine &Diags,
705                                                FileManager &FileMgr,
706                                                SourceManager &SourceMgr,
707                                                const FrontendOptions &Opts) {
708   SrcMgr::CharacteristicKind
709     Kind = Input.isSystem() ? SrcMgr::C_System : SrcMgr::C_User;
710 
711   if (Input.isBuffer()) {
712     SourceMgr.setMainFileID(SourceMgr.createFileID(Input.getBuffer(), Kind));
713     assert(!SourceMgr.getMainFileID().isInvalid() &&
714            "Couldn't establish MainFileID!");
715     return true;
716   }
717 
718   StringRef InputFile = Input.getFile();
719 
720   // Figure out where to get and map in the main file.
721   if (InputFile != "-") {
722     const FileEntry *File = FileMgr.getFile(InputFile, /*OpenFile=*/true);
723     if (!File) {
724       Diags.Report(diag::err_fe_error_reading) << InputFile;
725       return false;
726     }
727 
728     // The natural SourceManager infrastructure can't currently handle named
729     // pipes, but we would at least like to accept them for the main
730     // file. Detect them here, read them with the volatile flag so FileMgr will
731     // pick up the correct size, and simply override their contents as we do for
732     // STDIN.
733     if (File->isNamedPipe()) {
734       std::string ErrorStr;
735       if (llvm::MemoryBuffer *MB =
736               FileMgr.getBufferForFile(File, &ErrorStr, /*isVolatile=*/true)) {
737         // Create a new virtual file that will have the correct size.
738         File = FileMgr.getVirtualFile(InputFile, MB->getBufferSize(), 0);
739         SourceMgr.overrideFileContents(File, MB);
740       } else {
741         Diags.Report(diag::err_cannot_open_file) << InputFile << ErrorStr;
742         return false;
743       }
744     }
745 
746     SourceMgr.setMainFileID(
747         SourceMgr.createFileID(File, SourceLocation(), Kind));
748   } else {
749     llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> SBOrErr =
750         llvm::MemoryBuffer::getSTDIN();
751     if (std::error_code EC = SBOrErr.getError()) {
752       Diags.Report(diag::err_fe_error_reading_stdin) << EC.message();
753       return false;
754     }
755     std::unique_ptr<llvm::MemoryBuffer> SB = std::move(SBOrErr.get());
756 
757     const FileEntry *File = FileMgr.getVirtualFile(SB->getBufferIdentifier(),
758                                                    SB->getBufferSize(), 0);
759     SourceMgr.setMainFileID(
760         SourceMgr.createFileID(File, SourceLocation(), Kind));
761     SourceMgr.overrideFileContents(File, SB.release());
762   }
763 
764   assert(!SourceMgr.getMainFileID().isInvalid() &&
765          "Couldn't establish MainFileID!");
766   return true;
767 }
768 
769 // High-Level Operations
770 
771 bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
772   assert(hasDiagnostics() && "Diagnostics engine is not initialized!");
773   assert(!getFrontendOpts().ShowHelp && "Client must handle '-help'!");
774   assert(!getFrontendOpts().ShowVersion && "Client must handle '-version'!");
775 
776   // FIXME: Take this as an argument, once all the APIs we used have moved to
777   // taking it as an input instead of hard-coding llvm::errs.
778   raw_ostream &OS = llvm::errs();
779 
780   // Create the target instance.
781   setTarget(TargetInfo::CreateTargetInfo(getDiagnostics(),
782                                          getInvocation().TargetOpts));
783   if (!hasTarget())
784     return false;
785 
786   // Inform the target of the language options.
787   //
788   // FIXME: We shouldn't need to do this, the target should be immutable once
789   // created. This complexity should be lifted elsewhere.
790   getTarget().adjust(getLangOpts());
791 
792   // rewriter project will change target built-in bool type from its default.
793   if (getFrontendOpts().ProgramAction == frontend::RewriteObjC)
794     getTarget().noSignedCharForObjCBool();
795 
796   // Validate/process some options.
797   if (getHeaderSearchOpts().Verbose)
798     OS << "clang -cc1 version " CLANG_VERSION_STRING
799        << " based upon " << BACKEND_PACKAGE_STRING
800        << " default target " << llvm::sys::getDefaultTargetTriple() << "\n";
801 
802   if (getFrontendOpts().ShowTimers)
803     createFrontendTimer();
804 
805   if (getFrontendOpts().ShowStats)
806     llvm::EnableStatistics();
807 
808   for (unsigned i = 0, e = getFrontendOpts().Inputs.size(); i != e; ++i) {
809     // Reset the ID tables if we are reusing the SourceManager.
810     if (hasSourceManager())
811       getSourceManager().clearIDTables();
812 
813     if (Act.BeginSourceFile(*this, getFrontendOpts().Inputs[i])) {
814       Act.Execute();
815       Act.EndSourceFile();
816     }
817   }
818 
819   // Notify the diagnostic client that all files were processed.
820   getDiagnostics().getClient()->finish();
821 
822   if (getDiagnosticOpts().ShowCarets) {
823     // We can have multiple diagnostics sharing one diagnostic client.
824     // Get the total number of warnings/errors from the client.
825     unsigned NumWarnings = getDiagnostics().getClient()->getNumWarnings();
826     unsigned NumErrors = getDiagnostics().getClient()->getNumErrors();
827 
828     if (NumWarnings)
829       OS << NumWarnings << " warning" << (NumWarnings == 1 ? "" : "s");
830     if (NumWarnings && NumErrors)
831       OS << " and ";
832     if (NumErrors)
833       OS << NumErrors << " error" << (NumErrors == 1 ? "" : "s");
834     if (NumWarnings || NumErrors)
835       OS << " generated.\n";
836   }
837 
838   if (getFrontendOpts().ShowStats && hasFileManager()) {
839     getFileManager().PrintStats();
840     OS << "\n";
841   }
842 
843   return !getDiagnostics().getClient()->getNumErrors();
844 }
845 
846 /// \brief Determine the appropriate source input kind based on language
847 /// options.
848 static InputKind getSourceInputKindFromOptions(const LangOptions &LangOpts) {
849   if (LangOpts.OpenCL)
850     return IK_OpenCL;
851   if (LangOpts.CUDA)
852     return IK_CUDA;
853   if (LangOpts.ObjC1)
854     return LangOpts.CPlusPlus? IK_ObjCXX : IK_ObjC;
855   return LangOpts.CPlusPlus? IK_CXX : IK_C;
856 }
857 
858 /// \brief Compile a module file for the given module, using the options
859 /// provided by the importing compiler instance. Returns true if the module
860 /// was built without errors.
861 static bool compileModuleImpl(CompilerInstance &ImportingInstance,
862                               SourceLocation ImportLoc,
863                               Module *Module,
864                               StringRef ModuleFileName) {
865   ModuleMap &ModMap
866     = ImportingInstance.getPreprocessor().getHeaderSearchInfo().getModuleMap();
867 
868   // Construct a compiler invocation for creating this module.
869   IntrusiveRefCntPtr<CompilerInvocation> Invocation
870     (new CompilerInvocation(ImportingInstance.getInvocation()));
871 
872   PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
873 
874   // For any options that aren't intended to affect how a module is built,
875   // reset them to their default values.
876   Invocation->getLangOpts()->resetNonModularOptions();
877   PPOpts.resetNonModularOptions();
878 
879   // Remove any macro definitions that are explicitly ignored by the module.
880   // They aren't supposed to affect how the module is built anyway.
881   const HeaderSearchOptions &HSOpts = Invocation->getHeaderSearchOpts();
882   PPOpts.Macros.erase(
883       std::remove_if(PPOpts.Macros.begin(), PPOpts.Macros.end(),
884                      [&HSOpts](const std::pair<std::string, bool> &def) {
885         StringRef MacroDef = def.first;
886         return HSOpts.ModulesIgnoreMacros.count(MacroDef.split('=').first) > 0;
887       }),
888       PPOpts.Macros.end());
889 
890   // Note the name of the module we're building.
891   Invocation->getLangOpts()->CurrentModule = Module->getTopLevelModuleName();
892 
893   // Make sure that the failed-module structure has been allocated in
894   // the importing instance, and propagate the pointer to the newly-created
895   // instance.
896   PreprocessorOptions &ImportingPPOpts
897     = ImportingInstance.getInvocation().getPreprocessorOpts();
898   if (!ImportingPPOpts.FailedModules)
899     ImportingPPOpts.FailedModules = new PreprocessorOptions::FailedModulesSet;
900   PPOpts.FailedModules = ImportingPPOpts.FailedModules;
901 
902   // If there is a module map file, build the module using the module map.
903   // Set up the inputs/outputs so that we build the module from its umbrella
904   // header.
905   FrontendOptions &FrontendOpts = Invocation->getFrontendOpts();
906   FrontendOpts.OutputFile = ModuleFileName.str();
907   FrontendOpts.DisableFree = false;
908   FrontendOpts.GenerateGlobalModuleIndex = false;
909   FrontendOpts.Inputs.clear();
910   InputKind IK = getSourceInputKindFromOptions(*Invocation->getLangOpts());
911 
912   // Don't free the remapped file buffers; they are owned by our caller.
913   PPOpts.RetainRemappedFileBuffers = true;
914 
915   Invocation->getDiagnosticOpts().VerifyDiagnostics = 0;
916   assert(ImportingInstance.getInvocation().getModuleHash() ==
917          Invocation->getModuleHash() && "Module hash mismatch!");
918 
919   // Construct a compiler instance that will be used to actually create the
920   // module.
921   CompilerInstance Instance(/*BuildingModule=*/true);
922   Instance.setInvocation(&*Invocation);
923 
924   Instance.createDiagnostics(new ForwardingDiagnosticConsumer(
925                                    ImportingInstance.getDiagnosticClient()),
926                              /*ShouldOwnClient=*/true);
927 
928   Instance.setVirtualFileSystem(&ImportingInstance.getVirtualFileSystem());
929 
930   // Note that this module is part of the module build stack, so that we
931   // can detect cycles in the module graph.
932   Instance.setFileManager(&ImportingInstance.getFileManager());
933   Instance.createSourceManager(Instance.getFileManager());
934   SourceManager &SourceMgr = Instance.getSourceManager();
935   SourceMgr.setModuleBuildStack(
936     ImportingInstance.getSourceManager().getModuleBuildStack());
937   SourceMgr.pushModuleBuildStack(Module->getTopLevelModuleName(),
938     FullSourceLoc(ImportLoc, ImportingInstance.getSourceManager()));
939 
940   // If we're collecting module dependencies, we need to share a collector
941   // between all of the module CompilerInstances.
942   Instance.setModuleDepCollector(ImportingInstance.getModuleDepCollector());
943 
944   // Get or create the module map that we'll use to build this module.
945   std::string InferredModuleMapContent;
946   if (const FileEntry *ModuleMapFile =
947           ModMap.getContainingModuleMapFile(Module)) {
948     // Use the module map where this module resides.
949     FrontendOpts.Inputs.push_back(
950         FrontendInputFile(ModuleMapFile->getName(), IK));
951   } else {
952     llvm::raw_string_ostream OS(InferredModuleMapContent);
953     Module->print(OS);
954     OS.flush();
955     FrontendOpts.Inputs.push_back(
956         FrontendInputFile("__inferred_module.map", IK));
957 
958     llvm::MemoryBuffer *ModuleMapBuffer =
959         llvm::MemoryBuffer::getMemBuffer(InferredModuleMapContent);
960     ModuleMapFile = Instance.getFileManager().getVirtualFile(
961         "__inferred_module.map", InferredModuleMapContent.size(), 0);
962     SourceMgr.overrideFileContents(ModuleMapFile, ModuleMapBuffer);
963   }
964 
965   // Construct a module-generating action. Passing through the module map is
966   // safe because the FileManager is shared between the compiler instances.
967   GenerateModuleAction CreateModuleAction(
968       ModMap.getModuleMapFileForUniquing(Module), Module->IsSystem);
969 
970   // Execute the action to actually build the module in-place. Use a separate
971   // thread so that we get a stack large enough.
972   const unsigned ThreadStackSize = 8 << 20;
973   llvm::CrashRecoveryContext CRC;
974   CRC.RunSafelyOnThread([&]() { Instance.ExecuteAction(CreateModuleAction); },
975                         ThreadStackSize);
976 
977   // Delete the temporary module map file.
978   // FIXME: Even though we're executing under crash protection, it would still
979   // be nice to do this with RemoveFileOnSignal when we can. However, that
980   // doesn't make sense for all clients, so clean this up manually.
981   Instance.clearOutputFiles(/*EraseFiles=*/true);
982 
983   // We've rebuilt a module. If we're allowed to generate or update the global
984   // module index, record that fact in the importing compiler instance.
985   if (ImportingInstance.getFrontendOpts().GenerateGlobalModuleIndex) {
986     ImportingInstance.setBuildGlobalModuleIndex(true);
987   }
988 
989   return !Instance.getDiagnostics().hasErrorOccurred();
990 }
991 
992 static bool compileAndLoadModule(CompilerInstance &ImportingInstance,
993                                  SourceLocation ImportLoc,
994                                  SourceLocation ModuleNameLoc, Module *Module,
995                                  StringRef ModuleFileName) {
996   auto diagnoseBuildFailure = [&] {
997     ImportingInstance.getDiagnostics().Report(ModuleNameLoc,
998                                               diag::err_module_not_built)
999         << Module->Name << SourceRange(ImportLoc, ModuleNameLoc);
1000   };
1001 
1002   // FIXME: have LockFileManager return an error_code so that we can
1003   // avoid the mkdir when the directory already exists.
1004   StringRef Dir = llvm::sys::path::parent_path(ModuleFileName);
1005   llvm::sys::fs::create_directories(Dir);
1006 
1007   while (1) {
1008     unsigned ModuleLoadCapabilities = ASTReader::ARR_Missing;
1009     llvm::LockFileManager Locked(ModuleFileName);
1010     switch (Locked) {
1011     case llvm::LockFileManager::LFS_Error:
1012       return false;
1013 
1014     case llvm::LockFileManager::LFS_Owned:
1015       // We're responsible for building the module ourselves.
1016       if (!compileModuleImpl(ImportingInstance, ModuleNameLoc, Module,
1017                              ModuleFileName)) {
1018         diagnoseBuildFailure();
1019         return false;
1020       }
1021       break;
1022 
1023     case llvm::LockFileManager::LFS_Shared:
1024       // Someone else is responsible for building the module. Wait for them to
1025       // finish.
1026       if (Locked.waitForUnlock() == llvm::LockFileManager::Res_OwnerDied)
1027         continue; // try again to get the lock.
1028       ModuleLoadCapabilities |= ASTReader::ARR_OutOfDate;
1029       break;
1030     }
1031 
1032     // Try to read the module file, now that we've compiled it.
1033     ASTReader::ASTReadResult ReadResult =
1034         ImportingInstance.getModuleManager()->ReadAST(
1035             ModuleFileName, serialization::MK_Module, ImportLoc,
1036             ModuleLoadCapabilities);
1037 
1038     if (ReadResult == ASTReader::OutOfDate &&
1039         Locked == llvm::LockFileManager::LFS_Shared) {
1040       // The module may be out of date in the presence of file system races,
1041       // or if one of its imports depends on header search paths that are not
1042       // consistent with this ImportingInstance.  Try again...
1043       continue;
1044     } else if (ReadResult == ASTReader::Missing) {
1045       diagnoseBuildFailure();
1046     }
1047     return ReadResult == ASTReader::Success;
1048   }
1049 }
1050 
1051 /// \brief Diagnose differences between the current definition of the given
1052 /// configuration macro and the definition provided on the command line.
1053 static void checkConfigMacro(Preprocessor &PP, StringRef ConfigMacro,
1054                              Module *Mod, SourceLocation ImportLoc) {
1055   IdentifierInfo *Id = PP.getIdentifierInfo(ConfigMacro);
1056   SourceManager &SourceMgr = PP.getSourceManager();
1057 
1058   // If this identifier has never had a macro definition, then it could
1059   // not have changed.
1060   if (!Id->hadMacroDefinition())
1061     return;
1062 
1063   // If this identifier does not currently have a macro definition,
1064   // check whether it had one on the command line.
1065   if (!Id->hasMacroDefinition()) {
1066     MacroDirective::DefInfo LatestDef =
1067         PP.getMacroDirectiveHistory(Id)->getDefinition();
1068     for (MacroDirective::DefInfo Def = LatestDef; Def;
1069            Def = Def.getPreviousDefinition()) {
1070       FileID FID = SourceMgr.getFileID(Def.getLocation());
1071       if (FID.isInvalid())
1072         continue;
1073 
1074       // We only care about the predefines buffer.
1075       if (FID != PP.getPredefinesFileID())
1076         continue;
1077 
1078       // This macro was defined on the command line, then #undef'd later.
1079       // Complain.
1080       PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
1081         << true << ConfigMacro << Mod->getFullModuleName();
1082       if (LatestDef.isUndefined())
1083         PP.Diag(LatestDef.getUndefLocation(), diag::note_module_def_undef_here)
1084           << true;
1085       return;
1086     }
1087 
1088     // Okay: no definition in the predefines buffer.
1089     return;
1090   }
1091 
1092   // This identifier has a macro definition. Check whether we had a definition
1093   // on the command line.
1094   MacroDirective::DefInfo LatestDef =
1095       PP.getMacroDirectiveHistory(Id)->getDefinition();
1096   MacroDirective::DefInfo PredefinedDef;
1097   for (MacroDirective::DefInfo Def = LatestDef; Def;
1098          Def = Def.getPreviousDefinition()) {
1099     FileID FID = SourceMgr.getFileID(Def.getLocation());
1100     if (FID.isInvalid())
1101       continue;
1102 
1103     // We only care about the predefines buffer.
1104     if (FID != PP.getPredefinesFileID())
1105       continue;
1106 
1107     PredefinedDef = Def;
1108     break;
1109   }
1110 
1111   // If there was no definition for this macro in the predefines buffer,
1112   // complain.
1113   if (!PredefinedDef ||
1114       (!PredefinedDef.getLocation().isValid() &&
1115        PredefinedDef.getUndefLocation().isValid())) {
1116     PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
1117       << false << ConfigMacro << Mod->getFullModuleName();
1118     PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
1119       << false;
1120     return;
1121   }
1122 
1123   // If the current macro definition is the same as the predefined macro
1124   // definition, it's okay.
1125   if (LatestDef.getMacroInfo() == PredefinedDef.getMacroInfo() ||
1126       LatestDef.getMacroInfo()->isIdenticalTo(*PredefinedDef.getMacroInfo(),PP,
1127                                               /*Syntactically=*/true))
1128     return;
1129 
1130   // The macro definitions differ.
1131   PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
1132     << false << ConfigMacro << Mod->getFullModuleName();
1133   PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
1134     << false;
1135 }
1136 
1137 /// \brief Write a new timestamp file with the given path.
1138 static void writeTimestampFile(StringRef TimestampFile) {
1139   std::string ErrorInfo;
1140   llvm::raw_fd_ostream Out(TimestampFile.str().c_str(), ErrorInfo,
1141                            llvm::sys::fs::F_None);
1142 }
1143 
1144 /// \brief Prune the module cache of modules that haven't been accessed in
1145 /// a long time.
1146 static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
1147   struct stat StatBuf;
1148   llvm::SmallString<128> TimestampFile;
1149   TimestampFile = HSOpts.ModuleCachePath;
1150   llvm::sys::path::append(TimestampFile, "modules.timestamp");
1151 
1152   // Try to stat() the timestamp file.
1153   if (::stat(TimestampFile.c_str(), &StatBuf)) {
1154     // If the timestamp file wasn't there, create one now.
1155     if (errno == ENOENT) {
1156       writeTimestampFile(TimestampFile);
1157     }
1158     return;
1159   }
1160 
1161   // Check whether the time stamp is older than our pruning interval.
1162   // If not, do nothing.
1163   time_t TimeStampModTime = StatBuf.st_mtime;
1164   time_t CurrentTime = time(nullptr);
1165   if (CurrentTime - TimeStampModTime <= time_t(HSOpts.ModuleCachePruneInterval))
1166     return;
1167 
1168   // Write a new timestamp file so that nobody else attempts to prune.
1169   // There is a benign race condition here, if two Clang instances happen to
1170   // notice at the same time that the timestamp is out-of-date.
1171   writeTimestampFile(TimestampFile);
1172 
1173   // Walk the entire module cache, looking for unused module files and module
1174   // indices.
1175   std::error_code EC;
1176   SmallString<128> ModuleCachePathNative;
1177   llvm::sys::path::native(HSOpts.ModuleCachePath, ModuleCachePathNative);
1178   for (llvm::sys::fs::directory_iterator
1179          Dir(ModuleCachePathNative.str(), EC), DirEnd;
1180        Dir != DirEnd && !EC; Dir.increment(EC)) {
1181     // If we don't have a directory, there's nothing to look into.
1182     if (!llvm::sys::fs::is_directory(Dir->path()))
1183       continue;
1184 
1185     // Walk all of the files within this directory.
1186     for (llvm::sys::fs::directory_iterator File(Dir->path(), EC), FileEnd;
1187          File != FileEnd && !EC; File.increment(EC)) {
1188       // We only care about module and global module index files.
1189       StringRef Extension = llvm::sys::path::extension(File->path());
1190       if (Extension != ".pcm" && Extension != ".timestamp" &&
1191           llvm::sys::path::filename(File->path()) != "modules.idx")
1192         continue;
1193 
1194       // Look at this file. If we can't stat it, there's nothing interesting
1195       // there.
1196       if (::stat(File->path().c_str(), &StatBuf))
1197         continue;
1198 
1199       // If the file has been used recently enough, leave it there.
1200       time_t FileAccessTime = StatBuf.st_atime;
1201       if (CurrentTime - FileAccessTime <=
1202               time_t(HSOpts.ModuleCachePruneAfter)) {
1203         continue;
1204       }
1205 
1206       // Remove the file.
1207       llvm::sys::fs::remove(File->path());
1208 
1209       // Remove the timestamp file.
1210       std::string TimpestampFilename = File->path() + ".timestamp";
1211       llvm::sys::fs::remove(TimpestampFilename);
1212     }
1213 
1214     // If we removed all of the files in the directory, remove the directory
1215     // itself.
1216     if (llvm::sys::fs::directory_iterator(Dir->path(), EC) ==
1217             llvm::sys::fs::directory_iterator() && !EC)
1218       llvm::sys::fs::remove(Dir->path());
1219   }
1220 }
1221 
1222 void CompilerInstance::createModuleManager() {
1223   if (!ModuleManager) {
1224     if (!hasASTContext())
1225       createASTContext();
1226 
1227     // If we're not recursively building a module, check whether we
1228     // need to prune the module cache.
1229     if (getSourceManager().getModuleBuildStack().empty() &&
1230         getHeaderSearchOpts().ModuleCachePruneInterval > 0 &&
1231         getHeaderSearchOpts().ModuleCachePruneAfter > 0) {
1232       pruneModuleCache(getHeaderSearchOpts());
1233     }
1234 
1235     HeaderSearchOptions &HSOpts = getHeaderSearchOpts();
1236     std::string Sysroot = HSOpts.Sysroot;
1237     const PreprocessorOptions &PPOpts = getPreprocessorOpts();
1238     ModuleManager = new ASTReader(getPreprocessor(), *Context,
1239                                   Sysroot.empty() ? "" : Sysroot.c_str(),
1240                                   PPOpts.DisablePCHValidation,
1241                                   /*AllowASTWithCompilerErrors=*/false,
1242                                   /*AllowConfigurationMismatch=*/false,
1243                                   HSOpts.ModulesValidateSystemHeaders,
1244                                   getFrontendOpts().UseGlobalModuleIndex);
1245     if (hasASTConsumer()) {
1246       ModuleManager->setDeserializationListener(
1247         getASTConsumer().GetASTDeserializationListener());
1248       getASTContext().setASTMutationListener(
1249         getASTConsumer().GetASTMutationListener());
1250     }
1251     getASTContext().setExternalSource(ModuleManager);
1252     if (hasSema())
1253       ModuleManager->InitializeSema(getSema());
1254     if (hasASTConsumer())
1255       ModuleManager->StartTranslationUnit(&getASTConsumer());
1256   }
1257 }
1258 
1259 ModuleLoadResult
1260 CompilerInstance::loadModule(SourceLocation ImportLoc,
1261                              ModuleIdPath Path,
1262                              Module::NameVisibilityKind Visibility,
1263                              bool IsInclusionDirective) {
1264   // Determine what file we're searching from.
1265   StringRef ModuleName = Path[0].first->getName();
1266   SourceLocation ModuleNameLoc = Path[0].second;
1267 
1268   // If we've already handled this import, just return the cached result.
1269   // This one-element cache is important to eliminate redundant diagnostics
1270   // when both the preprocessor and parser see the same import declaration.
1271   if (!ImportLoc.isInvalid() && LastModuleImportLoc == ImportLoc) {
1272     // Make the named module visible.
1273     if (LastModuleImportResult && ModuleName != getLangOpts().CurrentModule &&
1274         ModuleName != getLangOpts().ImplementationOfModule)
1275       ModuleManager->makeModuleVisible(LastModuleImportResult, Visibility,
1276                                        ImportLoc, /*Complain=*/false);
1277     return LastModuleImportResult;
1278   }
1279 
1280   clang::Module *Module = nullptr;
1281 
1282   // If we don't already have information on this module, load the module now.
1283   llvm::DenseMap<const IdentifierInfo *, clang::Module *>::iterator Known
1284     = KnownModules.find(Path[0].first);
1285   if (Known != KnownModules.end()) {
1286     // Retrieve the cached top-level module.
1287     Module = Known->second;
1288   } else if (ModuleName == getLangOpts().CurrentModule ||
1289              ModuleName == getLangOpts().ImplementationOfModule) {
1290     // This is the module we're building.
1291     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
1292     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1293   } else {
1294     // Search for a module with the given name.
1295     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
1296     if (!Module) {
1297       getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_found)
1298       << ModuleName
1299       << SourceRange(ImportLoc, ModuleNameLoc);
1300       ModuleBuildFailed = true;
1301       return ModuleLoadResult();
1302     }
1303 
1304     std::string ModuleFileName =
1305         PP->getHeaderSearchInfo().getModuleFileName(Module);
1306 
1307     // If we don't already have an ASTReader, create one now.
1308     if (!ModuleManager)
1309       createModuleManager();
1310 
1311     if (TheDependencyFileGenerator)
1312       TheDependencyFileGenerator->AttachToASTReader(*ModuleManager);
1313 
1314     if (ModuleDepCollector)
1315       ModuleDepCollector->attachToASTReader(*ModuleManager);
1316 
1317     for (auto &Listener : DependencyCollectors)
1318       Listener->attachToASTReader(*ModuleManager);
1319 
1320     // Try to load the module file.
1321     unsigned ARRFlags = ASTReader::ARR_OutOfDate | ASTReader::ARR_Missing;
1322     switch (ModuleManager->ReadAST(ModuleFileName, serialization::MK_Module,
1323                                    ImportLoc, ARRFlags)) {
1324     case ASTReader::Success:
1325       break;
1326 
1327     case ASTReader::OutOfDate:
1328     case ASTReader::Missing: {
1329       // The module file is missing or out-of-date. Build it.
1330       assert(Module && "missing module file");
1331       // Check whether there is a cycle in the module graph.
1332       ModuleBuildStack ModPath = getSourceManager().getModuleBuildStack();
1333       ModuleBuildStack::iterator Pos = ModPath.begin(), PosEnd = ModPath.end();
1334       for (; Pos != PosEnd; ++Pos) {
1335         if (Pos->first == ModuleName)
1336           break;
1337       }
1338 
1339       if (Pos != PosEnd) {
1340         SmallString<256> CyclePath;
1341         for (; Pos != PosEnd; ++Pos) {
1342           CyclePath += Pos->first;
1343           CyclePath += " -> ";
1344         }
1345         CyclePath += ModuleName;
1346 
1347         getDiagnostics().Report(ModuleNameLoc, diag::err_module_cycle)
1348           << ModuleName << CyclePath;
1349         return ModuleLoadResult();
1350       }
1351 
1352       getDiagnostics().Report(ImportLoc, diag::remark_module_build)
1353           << ModuleName << ModuleFileName;
1354 
1355       // Check whether we have already attempted to build this module (but
1356       // failed).
1357       if (getPreprocessorOpts().FailedModules &&
1358           getPreprocessorOpts().FailedModules->hasAlreadyFailed(ModuleName)) {
1359         getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_built)
1360           << ModuleName
1361           << SourceRange(ImportLoc, ModuleNameLoc);
1362         ModuleBuildFailed = true;
1363         return ModuleLoadResult();
1364       }
1365 
1366       // Try to compile and then load the module.
1367       if (!compileAndLoadModule(*this, ImportLoc, ModuleNameLoc, Module,
1368                                 ModuleFileName)) {
1369         if (getPreprocessorOpts().FailedModules)
1370           getPreprocessorOpts().FailedModules->addFailed(ModuleName);
1371         KnownModules[Path[0].first] = nullptr;
1372         ModuleBuildFailed = true;
1373         return ModuleLoadResult();
1374       }
1375 
1376       // Okay, we've rebuilt and now loaded the module.
1377       break;
1378     }
1379 
1380     case ASTReader::VersionMismatch:
1381     case ASTReader::ConfigurationMismatch:
1382     case ASTReader::HadErrors:
1383       ModuleLoader::HadFatalFailure = true;
1384       // FIXME: The ASTReader will already have complained, but can we showhorn
1385       // that diagnostic information into a more useful form?
1386       KnownModules[Path[0].first] = nullptr;
1387       return ModuleLoadResult();
1388 
1389     case ASTReader::Failure:
1390       ModuleLoader::HadFatalFailure = true;
1391       // Already complained, but note now that we failed.
1392       KnownModules[Path[0].first] = nullptr;
1393       ModuleBuildFailed = true;
1394       return ModuleLoadResult();
1395     }
1396 
1397     // Cache the result of this top-level module lookup for later.
1398     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1399   }
1400 
1401   // If we never found the module, fail.
1402   if (!Module)
1403     return ModuleLoadResult();
1404 
1405   // Verify that the rest of the module path actually corresponds to
1406   // a submodule.
1407   if (Path.size() > 1) {
1408     for (unsigned I = 1, N = Path.size(); I != N; ++I) {
1409       StringRef Name = Path[I].first->getName();
1410       clang::Module *Sub = Module->findSubmodule(Name);
1411 
1412       if (!Sub) {
1413         // Attempt to perform typo correction to find a module name that works.
1414         SmallVector<StringRef, 2> Best;
1415         unsigned BestEditDistance = (std::numeric_limits<unsigned>::max)();
1416 
1417         for (clang::Module::submodule_iterator J = Module->submodule_begin(),
1418                                             JEnd = Module->submodule_end();
1419              J != JEnd; ++J) {
1420           unsigned ED = Name.edit_distance((*J)->Name,
1421                                            /*AllowReplacements=*/true,
1422                                            BestEditDistance);
1423           if (ED <= BestEditDistance) {
1424             if (ED < BestEditDistance) {
1425               Best.clear();
1426               BestEditDistance = ED;
1427             }
1428 
1429             Best.push_back((*J)->Name);
1430           }
1431         }
1432 
1433         // If there was a clear winner, user it.
1434         if (Best.size() == 1) {
1435           getDiagnostics().Report(Path[I].second,
1436                                   diag::err_no_submodule_suggest)
1437             << Path[I].first << Module->getFullModuleName() << Best[0]
1438             << SourceRange(Path[0].second, Path[I-1].second)
1439             << FixItHint::CreateReplacement(SourceRange(Path[I].second),
1440                                             Best[0]);
1441 
1442           Sub = Module->findSubmodule(Best[0]);
1443         }
1444       }
1445 
1446       if (!Sub) {
1447         // No submodule by this name. Complain, and don't look for further
1448         // submodules.
1449         getDiagnostics().Report(Path[I].second, diag::err_no_submodule)
1450           << Path[I].first << Module->getFullModuleName()
1451           << SourceRange(Path[0].second, Path[I-1].second);
1452         break;
1453       }
1454 
1455       Module = Sub;
1456     }
1457   }
1458 
1459   // Don't make the module visible if we are in the implementation.
1460   if (ModuleName == getLangOpts().ImplementationOfModule)
1461     return ModuleLoadResult(Module, false);
1462 
1463   // Make the named module visible, if it's not already part of the module
1464   // we are parsing.
1465   if (ModuleName != getLangOpts().CurrentModule) {
1466     if (!Module->IsFromModuleFile) {
1467       // We have an umbrella header or directory that doesn't actually include
1468       // all of the headers within the directory it covers. Complain about
1469       // this missing submodule and recover by forgetting that we ever saw
1470       // this submodule.
1471       // FIXME: Should we detect this at module load time? It seems fairly
1472       // expensive (and rare).
1473       getDiagnostics().Report(ImportLoc, diag::warn_missing_submodule)
1474         << Module->getFullModuleName()
1475         << SourceRange(Path.front().second, Path.back().second);
1476 
1477       return ModuleLoadResult(nullptr, true);
1478     }
1479 
1480     // Check whether this module is available.
1481     clang::Module::Requirement Requirement;
1482     clang::Module::HeaderDirective MissingHeader;
1483     if (!Module->isAvailable(getLangOpts(), getTarget(), Requirement,
1484                              MissingHeader)) {
1485       if (MissingHeader.FileNameLoc.isValid()) {
1486         getDiagnostics().Report(MissingHeader.FileNameLoc,
1487                                 diag::err_module_header_missing)
1488           << MissingHeader.IsUmbrella << MissingHeader.FileName;
1489       } else {
1490         getDiagnostics().Report(ImportLoc, diag::err_module_unavailable)
1491           << Module->getFullModuleName()
1492           << Requirement.second << Requirement.first
1493           << SourceRange(Path.front().second, Path.back().second);
1494       }
1495       LastModuleImportLoc = ImportLoc;
1496       LastModuleImportResult = ModuleLoadResult();
1497       return ModuleLoadResult();
1498     }
1499 
1500     ModuleManager->makeModuleVisible(Module, Visibility, ImportLoc,
1501                                      /*Complain=*/true);
1502   }
1503 
1504   // Check for any configuration macros that have changed.
1505   clang::Module *TopModule = Module->getTopLevelModule();
1506   for (unsigned I = 0, N = TopModule->ConfigMacros.size(); I != N; ++I) {
1507     checkConfigMacro(getPreprocessor(), TopModule->ConfigMacros[I],
1508                      Module, ImportLoc);
1509   }
1510 
1511   // If this module import was due to an inclusion directive, create an
1512   // implicit import declaration to capture it in the AST.
1513   if (IsInclusionDirective && hasASTContext()) {
1514     TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
1515     ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
1516                                                      ImportLoc, Module,
1517                                                      Path.back().second);
1518     TU->addDecl(ImportD);
1519     if (Consumer)
1520       Consumer->HandleImplicitImportDecl(ImportD);
1521   }
1522 
1523   LastModuleImportLoc = ImportLoc;
1524   LastModuleImportResult = ModuleLoadResult(Module, false);
1525   return LastModuleImportResult;
1526 }
1527 
1528 void CompilerInstance::makeModuleVisible(Module *Mod,
1529                                          Module::NameVisibilityKind Visibility,
1530                                          SourceLocation ImportLoc,
1531                                          bool Complain){
1532   ModuleManager->makeModuleVisible(Mod, Visibility, ImportLoc, Complain);
1533 }
1534 
1535 GlobalModuleIndex *CompilerInstance::loadGlobalModuleIndex(
1536     SourceLocation TriggerLoc) {
1537   if (!ModuleManager)
1538     createModuleManager();
1539   // Can't do anything if we don't have the module manager.
1540   if (!ModuleManager)
1541     return nullptr;
1542   // Get an existing global index.  This loads it if not already
1543   // loaded.
1544   ModuleManager->loadGlobalIndex();
1545   GlobalModuleIndex *GlobalIndex = ModuleManager->getGlobalIndex();
1546   // If the global index doesn't exist, create it.
1547   if (!GlobalIndex && shouldBuildGlobalModuleIndex() && hasFileManager() &&
1548       hasPreprocessor()) {
1549     llvm::sys::fs::create_directories(
1550       getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
1551     GlobalModuleIndex::writeIndex(
1552       getFileManager(),
1553       getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
1554     ModuleManager->resetForReload();
1555     ModuleManager->loadGlobalIndex();
1556     GlobalIndex = ModuleManager->getGlobalIndex();
1557   }
1558   // For finding modules needing to be imported for fixit messages,
1559   // we need to make the global index cover all modules, so we do that here.
1560   if (!HaveFullGlobalModuleIndex && GlobalIndex && !buildingModule()) {
1561     ModuleMap &MMap = getPreprocessor().getHeaderSearchInfo().getModuleMap();
1562     bool RecreateIndex = false;
1563     for (ModuleMap::module_iterator I = MMap.module_begin(),
1564         E = MMap.module_end(); I != E; ++I) {
1565       Module *TheModule = I->second;
1566       const FileEntry *Entry = TheModule->getASTFile();
1567       if (!Entry) {
1568         SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 2> Path;
1569         Path.push_back(std::make_pair(
1570 				  getPreprocessor().getIdentifierInfo(TheModule->Name), TriggerLoc));
1571         std::reverse(Path.begin(), Path.end());
1572 		    // Load a module as hidden.  This also adds it to the global index.
1573         loadModule(TheModule->DefinitionLoc, Path,
1574                                              Module::Hidden, false);
1575         RecreateIndex = true;
1576       }
1577     }
1578     if (RecreateIndex) {
1579       GlobalModuleIndex::writeIndex(
1580         getFileManager(),
1581         getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
1582       ModuleManager->resetForReload();
1583       ModuleManager->loadGlobalIndex();
1584       GlobalIndex = ModuleManager->getGlobalIndex();
1585     }
1586     HaveFullGlobalModuleIndex = true;
1587   }
1588   return GlobalIndex;
1589 }
1590 
1591 // Check global module index for missing imports.
1592 bool
1593 CompilerInstance::lookupMissingImports(StringRef Name,
1594                                        SourceLocation TriggerLoc) {
1595   // Look for the symbol in non-imported modules, but only if an error
1596   // actually occurred.
1597   if (!buildingModule()) {
1598     // Load global module index, or retrieve a previously loaded one.
1599     GlobalModuleIndex *GlobalIndex = loadGlobalModuleIndex(
1600       TriggerLoc);
1601 
1602     // Only if we have a global index.
1603     if (GlobalIndex) {
1604       GlobalModuleIndex::HitSet FoundModules;
1605 
1606       // Find the modules that reference the identifier.
1607       // Note that this only finds top-level modules.
1608       // We'll let diagnoseTypo find the actual declaration module.
1609       if (GlobalIndex->lookupIdentifier(Name, FoundModules))
1610         return true;
1611     }
1612   }
1613 
1614   return false;
1615 }
1616