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      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(
     55     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
     56     bool BuildingModule)
     57     : ModuleLoader(BuildingModule), Invocation(new CompilerInvocation()),
     58       ModuleManager(nullptr), ThePCHContainerOperations(PCHContainerOps),
     59       BuildGlobalModuleIndex(false), HaveFullGlobalModuleIndex(false),
     60       ModuleBuildFailed(false) {}
     61 
     62 CompilerInstance::~CompilerInstance() {
     63   assert(OutputFiles.empty() && "Still output files in flight?");
     64 }
     65 
     66 void CompilerInstance::setInvocation(CompilerInvocation *Value) {
     67   Invocation = Value;
     68 }
     69 
     70 bool CompilerInstance::shouldBuildGlobalModuleIndex() const {
     71   return (BuildGlobalModuleIndex ||
     72           (ModuleManager && ModuleManager->isGlobalIndexUnavailable() &&
     73            getFrontendOpts().GenerateGlobalModuleIndex)) &&
     74          !ModuleBuildFailed;
     75 }
     76 
     77 void CompilerInstance::setDiagnostics(DiagnosticsEngine *Value) {
     78   Diagnostics = Value;
     79 }
     80 
     81 void CompilerInstance::setTarget(TargetInfo *Value) { Target = Value; }
     82 void CompilerInstance::setAuxTarget(TargetInfo *Value) { AuxTarget = Value; }
     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) {
     99   Context = Value;
    100 
    101   if (Context && Consumer)
    102     getASTConsumer().Initialize(getASTContext());
    103 }
    104 
    105 void CompilerInstance::setSema(Sema *S) {
    106   TheSema.reset(S);
    107 }
    108 
    109 void CompilerInstance::setASTConsumer(std::unique_ptr<ASTConsumer> Value) {
    110   Consumer = std::move(Value);
    111 
    112   if (Context && Consumer)
    113     getASTConsumer().Initialize(getASTContext());
    114 }
    115 
    116 void CompilerInstance::setCodeCompletionConsumer(CodeCompleteConsumer *Value) {
    117   CompletionConsumer.reset(Value);
    118 }
    119 
    120 std::unique_ptr<Sema> CompilerInstance::takeSema() {
    121   return std::move(TheSema);
    122 }
    123 
    124 IntrusiveRefCntPtr<ASTReader> CompilerInstance::getModuleManager() const {
    125   return ModuleManager;
    126 }
    127 void CompilerInstance::setModuleManager(IntrusiveRefCntPtr<ASTReader> Reader) {
    128   ModuleManager = Reader;
    129 }
    130 
    131 std::shared_ptr<ModuleDependencyCollector>
    132 CompilerInstance::getModuleDepCollector() const {
    133   return ModuleDepCollector;
    134 }
    135 
    136 void CompilerInstance::setModuleDepCollector(
    137     std::shared_ptr<ModuleDependencyCollector> Collector) {
    138   ModuleDepCollector = Collector;
    139 }
    140 
    141 // Diagnostics
    142 static void SetUpDiagnosticLog(DiagnosticOptions *DiagOpts,
    143                                const CodeGenOptions *CodeGenOpts,
    144                                DiagnosticsEngine &Diags) {
    145   std::error_code EC;
    146   std::unique_ptr<raw_ostream> StreamOwner;
    147   raw_ostream *OS = &llvm::errs();
    148   if (DiagOpts->DiagnosticLogFile != "-") {
    149     // Create the output stream.
    150     auto FileOS = llvm::make_unique<llvm::raw_fd_ostream>(
    151         DiagOpts->DiagnosticLogFile, EC,
    152         llvm::sys::fs::F_Append | llvm::sys::fs::F_Text);
    153     if (EC) {
    154       Diags.Report(diag::warn_fe_cc_log_diagnostics_failure)
    155           << DiagOpts->DiagnosticLogFile << EC.message();
    156     } else {
    157       FileOS->SetUnbuffered();
    158       OS = FileOS.get();
    159       StreamOwner = std::move(FileOS);
    160     }
    161   }
    162 
    163   // Chain in the diagnostic client which will log the diagnostics.
    164   auto Logger = llvm::make_unique<LogDiagnosticPrinter>(*OS, DiagOpts,
    165                                                         std::move(StreamOwner));
    166   if (CodeGenOpts)
    167     Logger->setDwarfDebugFlags(CodeGenOpts->DwarfDebugFlags);
    168   assert(Diags.ownsClient());
    169   Diags.setClient(
    170       new ChainedDiagnosticConsumer(Diags.takeClient(), std::move(Logger)));
    171 }
    172 
    173 static void SetupSerializedDiagnostics(DiagnosticOptions *DiagOpts,
    174                                        DiagnosticsEngine &Diags,
    175                                        StringRef OutputFile) {
    176   auto SerializedConsumer =
    177       clang::serialized_diags::create(OutputFile, DiagOpts);
    178 
    179   if (Diags.ownsClient()) {
    180     Diags.setClient(new ChainedDiagnosticConsumer(
    181         Diags.takeClient(), std::move(SerializedConsumer)));
    182   } else {
    183     Diags.setClient(new ChainedDiagnosticConsumer(
    184         Diags.getClient(), std::move(SerializedConsumer)));
    185   }
    186 }
    187 
    188 void CompilerInstance::createDiagnostics(DiagnosticConsumer *Client,
    189                                          bool ShouldOwnClient) {
    190   Diagnostics = createDiagnostics(&getDiagnosticOpts(), Client,
    191                                   ShouldOwnClient, &getCodeGenOpts());
    192 }
    193 
    194 IntrusiveRefCntPtr<DiagnosticsEngine>
    195 CompilerInstance::createDiagnostics(DiagnosticOptions *Opts,
    196                                     DiagnosticConsumer *Client,
    197                                     bool ShouldOwnClient,
    198                                     const CodeGenOptions *CodeGenOpts) {
    199   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
    200   IntrusiveRefCntPtr<DiagnosticsEngine>
    201       Diags(new DiagnosticsEngine(DiagID, Opts));
    202 
    203   // Create the diagnostic client for reporting errors or for
    204   // implementing -verify.
    205   if (Client) {
    206     Diags->setClient(Client, ShouldOwnClient);
    207   } else
    208     Diags->setClient(new TextDiagnosticPrinter(llvm::errs(), Opts));
    209 
    210   // Chain in -verify checker, if requested.
    211   if (Opts->VerifyDiagnostics)
    212     Diags->setClient(new VerifyDiagnosticConsumer(*Diags));
    213 
    214   // Chain in -diagnostic-log-file dumper, if requested.
    215   if (!Opts->DiagnosticLogFile.empty())
    216     SetUpDiagnosticLog(Opts, CodeGenOpts, *Diags);
    217 
    218   if (!Opts->DiagnosticSerializationFile.empty())
    219     SetupSerializedDiagnostics(Opts, *Diags,
    220                                Opts->DiagnosticSerializationFile);
    221 
    222   // Configure our handling of diagnostics.
    223   ProcessWarningOptions(*Diags, *Opts);
    224 
    225   return Diags;
    226 }
    227 
    228 // File Manager
    229 
    230 void CompilerInstance::createFileManager() {
    231   if (!hasVirtualFileSystem()) {
    232     // TODO: choose the virtual file system based on the CompilerInvocation.
    233     setVirtualFileSystem(vfs::getRealFileSystem());
    234   }
    235   FileMgr = new FileManager(getFileSystemOpts(), VirtualFileSystem);
    236 }
    237 
    238 // Source Manager
    239 
    240 void CompilerInstance::createSourceManager(FileManager &FileMgr) {
    241   SourceMgr = new SourceManager(getDiagnostics(), FileMgr);
    242 }
    243 
    244 // Initialize the remapping of files to alternative contents, e.g.,
    245 // those specified through other files.
    246 static void InitializeFileRemapping(DiagnosticsEngine &Diags,
    247                                     SourceManager &SourceMgr,
    248                                     FileManager &FileMgr,
    249                                     const PreprocessorOptions &InitOpts) {
    250   // Remap files in the source manager (with buffers).
    251   for (const auto &RB : InitOpts.RemappedFileBuffers) {
    252     // Create the file entry for the file that we're mapping from.
    253     const FileEntry *FromFile =
    254         FileMgr.getVirtualFile(RB.first, RB.second->getBufferSize(), 0);
    255     if (!FromFile) {
    256       Diags.Report(diag::err_fe_remap_missing_from_file) << RB.first;
    257       if (!InitOpts.RetainRemappedFileBuffers)
    258         delete RB.second;
    259       continue;
    260     }
    261 
    262     // Override the contents of the "from" file with the contents of
    263     // the "to" file.
    264     SourceMgr.overrideFileContents(FromFile, RB.second,
    265                                    InitOpts.RetainRemappedFileBuffers);
    266   }
    267 
    268   // Remap files in the source manager (with other files).
    269   for (const auto &RF : InitOpts.RemappedFiles) {
    270     // Find the file that we're mapping to.
    271     const FileEntry *ToFile = FileMgr.getFile(RF.second);
    272     if (!ToFile) {
    273       Diags.Report(diag::err_fe_remap_missing_to_file) << RF.first << RF.second;
    274       continue;
    275     }
    276 
    277     // Create the file entry for the file that we're mapping from.
    278     const FileEntry *FromFile =
    279         FileMgr.getVirtualFile(RF.first, ToFile->getSize(), 0);
    280     if (!FromFile) {
    281       Diags.Report(diag::err_fe_remap_missing_from_file) << RF.first;
    282       continue;
    283     }
    284 
    285     // Override the contents of the "from" file with the contents of
    286     // the "to" file.
    287     SourceMgr.overrideFileContents(FromFile, ToFile);
    288   }
    289 
    290   SourceMgr.setOverridenFilesKeepOriginalName(
    291       InitOpts.RemappedFilesKeepOriginalName);
    292 }
    293 
    294 // Preprocessor
    295 
    296 void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
    297   const PreprocessorOptions &PPOpts = getPreprocessorOpts();
    298 
    299   // Create a PTH manager if we are using some form of a token cache.
    300   PTHManager *PTHMgr = nullptr;
    301   if (!PPOpts.TokenCache.empty())
    302     PTHMgr = PTHManager::Create(PPOpts.TokenCache, getDiagnostics());
    303 
    304   // Create the Preprocessor.
    305   HeaderSearch *HeaderInfo = new HeaderSearch(&getHeaderSearchOpts(),
    306                                               getSourceManager(),
    307                                               getDiagnostics(),
    308                                               getLangOpts(),
    309                                               &getTarget());
    310   PP = new Preprocessor(&getPreprocessorOpts(), getDiagnostics(), getLangOpts(),
    311                         getSourceManager(), *HeaderInfo, *this, PTHMgr,
    312                         /*OwnsHeaderSearch=*/true, TUKind);
    313   PP->Initialize(getTarget(), getAuxTarget());
    314 
    315   // Note that this is different then passing PTHMgr to Preprocessor's ctor.
    316   // That argument is used as the IdentifierInfoLookup argument to
    317   // IdentifierTable's ctor.
    318   if (PTHMgr) {
    319     PTHMgr->setPreprocessor(&*PP);
    320     PP->setPTHManager(PTHMgr);
    321   }
    322 
    323   if (PPOpts.DetailedRecord)
    324     PP->createPreprocessingRecord();
    325 
    326   // Apply remappings to the source manager.
    327   InitializeFileRemapping(PP->getDiagnostics(), PP->getSourceManager(),
    328                           PP->getFileManager(), PPOpts);
    329 
    330   // Predefine macros and configure the preprocessor.
    331   InitializePreprocessor(*PP, PPOpts, getPCHContainerReader(),
    332                          getFrontendOpts());
    333 
    334   // Initialize the header search object.
    335   ApplyHeaderSearchOptions(PP->getHeaderSearchInfo(), getHeaderSearchOpts(),
    336                            PP->getLangOpts(), PP->getTargetInfo().getTriple());
    337 
    338   PP->setPreprocessedOutput(getPreprocessorOutputOpts().ShowCPP);
    339 
    340   if (PP->getLangOpts().Modules && PP->getLangOpts().ImplicitModules)
    341     PP->getHeaderSearchInfo().setModuleCachePath(getSpecificModuleCachePath());
    342 
    343   // Handle generating dependencies, if requested.
    344   const DependencyOutputOptions &DepOpts = getDependencyOutputOpts();
    345   if (!DepOpts.OutputFile.empty())
    346     TheDependencyFileGenerator.reset(
    347         DependencyFileGenerator::CreateAndAttachToPreprocessor(*PP, DepOpts));
    348   if (!DepOpts.DOTOutputFile.empty())
    349     AttachDependencyGraphGen(*PP, DepOpts.DOTOutputFile,
    350                              getHeaderSearchOpts().Sysroot);
    351 
    352   for (auto &Listener : DependencyCollectors)
    353     Listener->attachToPreprocessor(*PP);
    354 
    355   // If we don't have a collector, but we are collecting module dependencies,
    356   // then we're the top level compiler instance and need to create one.
    357   if (!ModuleDepCollector && !DepOpts.ModuleDependencyOutputDir.empty())
    358     ModuleDepCollector = std::make_shared<ModuleDependencyCollector>(
    359         DepOpts.ModuleDependencyOutputDir);
    360 
    361   // Handle generating header include information, if requested.
    362   if (DepOpts.ShowHeaderIncludes)
    363     AttachHeaderIncludeGen(*PP, DepOpts.ExtraDeps);
    364   if (!DepOpts.HeaderIncludeOutputFile.empty()) {
    365     StringRef OutputPath = DepOpts.HeaderIncludeOutputFile;
    366     if (OutputPath == "-")
    367       OutputPath = "";
    368     AttachHeaderIncludeGen(*PP, DepOpts.ExtraDeps,
    369                            /*ShowAllHeaders=*/true, OutputPath,
    370                            /*ShowDepth=*/false);
    371   }
    372 
    373   if (DepOpts.PrintShowIncludes) {
    374     AttachHeaderIncludeGen(*PP, DepOpts.ExtraDeps,
    375                            /*ShowAllHeaders=*/false, /*OutputPath=*/"",
    376                            /*ShowDepth=*/true, /*MSStyle=*/true);
    377   }
    378 }
    379 
    380 std::string CompilerInstance::getSpecificModuleCachePath() {
    381   // Set up the module path, including the hash for the
    382   // module-creation options.
    383   SmallString<256> SpecificModuleCache(getHeaderSearchOpts().ModuleCachePath);
    384   if (!SpecificModuleCache.empty() && !getHeaderSearchOpts().DisableModuleHash)
    385     llvm::sys::path::append(SpecificModuleCache,
    386                             getInvocation().getModuleHash());
    387   return SpecificModuleCache.str();
    388 }
    389 
    390 // ASTContext
    391 
    392 void CompilerInstance::createASTContext() {
    393   Preprocessor &PP = getPreprocessor();
    394   auto *Context = new ASTContext(getLangOpts(), PP.getSourceManager(),
    395                                  PP.getIdentifierTable(), PP.getSelectorTable(),
    396                                  PP.getBuiltinInfo());
    397   Context->InitBuiltinTypes(getTarget(), getAuxTarget());
    398   setASTContext(Context);
    399 }
    400 
    401 // ExternalASTSource
    402 
    403 void CompilerInstance::createPCHExternalASTSource(
    404     StringRef Path, bool DisablePCHValidation, bool AllowPCHWithCompilerErrors,
    405     void *DeserializationListener, bool OwnDeserializationListener) {
    406   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
    407   ModuleManager = createPCHExternalASTSource(
    408       Path, getHeaderSearchOpts().Sysroot, DisablePCHValidation,
    409       AllowPCHWithCompilerErrors, getPreprocessor(), getASTContext(),
    410       getPCHContainerReader(),
    411       getFrontendOpts().ModuleFileExtensions,
    412       DeserializationListener,
    413       OwnDeserializationListener, Preamble,
    414       getFrontendOpts().UseGlobalModuleIndex);
    415 }
    416 
    417 IntrusiveRefCntPtr<ASTReader> CompilerInstance::createPCHExternalASTSource(
    418     StringRef Path, StringRef Sysroot, bool DisablePCHValidation,
    419     bool AllowPCHWithCompilerErrors, Preprocessor &PP, ASTContext &Context,
    420     const PCHContainerReader &PCHContainerRdr,
    421     ArrayRef<IntrusiveRefCntPtr<ModuleFileExtension>> Extensions,
    422     void *DeserializationListener, bool OwnDeserializationListener,
    423     bool Preamble, bool UseGlobalModuleIndex) {
    424   HeaderSearchOptions &HSOpts = PP.getHeaderSearchInfo().getHeaderSearchOpts();
    425 
    426   IntrusiveRefCntPtr<ASTReader> Reader(new ASTReader(
    427       PP, Context, PCHContainerRdr, Extensions,
    428       Sysroot.empty() ? "" : Sysroot.data(), DisablePCHValidation,
    429       AllowPCHWithCompilerErrors, /*AllowConfigurationMismatch*/ false,
    430       HSOpts.ModulesValidateSystemHeaders, UseGlobalModuleIndex));
    431 
    432   // We need the external source to be set up before we read the AST, because
    433   // eagerly-deserialized declarations may use it.
    434   Context.setExternalSource(Reader.get());
    435 
    436   Reader->setDeserializationListener(
    437       static_cast<ASTDeserializationListener *>(DeserializationListener),
    438       /*TakeOwnership=*/OwnDeserializationListener);
    439   switch (Reader->ReadAST(Path,
    440                           Preamble ? serialization::MK_Preamble
    441                                    : serialization::MK_PCH,
    442                           SourceLocation(),
    443                           ASTReader::ARR_None)) {
    444   case ASTReader::Success:
    445     // Set the predefines buffer as suggested by the PCH reader. Typically, the
    446     // predefines buffer will be empty.
    447     PP.setPredefines(Reader->getSuggestedPredefines());
    448     return Reader;
    449 
    450   case ASTReader::Failure:
    451     // Unrecoverable failure: don't even try to process the input file.
    452     break;
    453 
    454   case ASTReader::Missing:
    455   case ASTReader::OutOfDate:
    456   case ASTReader::VersionMismatch:
    457   case ASTReader::ConfigurationMismatch:
    458   case ASTReader::HadErrors:
    459     // No suitable PCH file could be found. Return an error.
    460     break;
    461   }
    462 
    463   Context.setExternalSource(nullptr);
    464   return nullptr;
    465 }
    466 
    467 // Code Completion
    468 
    469 static bool EnableCodeCompletion(Preprocessor &PP,
    470                                  const std::string &Filename,
    471                                  unsigned Line,
    472                                  unsigned Column) {
    473   // Tell the source manager to chop off the given file at a specific
    474   // line and column.
    475   const FileEntry *Entry = PP.getFileManager().getFile(Filename);
    476   if (!Entry) {
    477     PP.getDiagnostics().Report(diag::err_fe_invalid_code_complete_file)
    478       << Filename;
    479     return true;
    480   }
    481 
    482   // Truncate the named file at the given line/column.
    483   PP.SetCodeCompletionPoint(Entry, Line, Column);
    484   return false;
    485 }
    486 
    487 void CompilerInstance::createCodeCompletionConsumer() {
    488   const ParsedSourceLocation &Loc = getFrontendOpts().CodeCompletionAt;
    489   if (!CompletionConsumer) {
    490     setCodeCompletionConsumer(
    491       createCodeCompletionConsumer(getPreprocessor(),
    492                                    Loc.FileName, Loc.Line, Loc.Column,
    493                                    getFrontendOpts().CodeCompleteOpts,
    494                                    llvm::outs()));
    495     if (!CompletionConsumer)
    496       return;
    497   } else if (EnableCodeCompletion(getPreprocessor(), Loc.FileName,
    498                                   Loc.Line, Loc.Column)) {
    499     setCodeCompletionConsumer(nullptr);
    500     return;
    501   }
    502 
    503   if (CompletionConsumer->isOutputBinary() &&
    504       llvm::sys::ChangeStdoutToBinary()) {
    505     getPreprocessor().getDiagnostics().Report(diag::err_fe_stdout_binary);
    506     setCodeCompletionConsumer(nullptr);
    507   }
    508 }
    509 
    510 void CompilerInstance::createFrontendTimer() {
    511   FrontendTimerGroup.reset(new llvm::TimerGroup("Clang front-end time report"));
    512   FrontendTimer.reset(
    513       new llvm::Timer("Clang front-end timer", *FrontendTimerGroup));
    514 }
    515 
    516 CodeCompleteConsumer *
    517 CompilerInstance::createCodeCompletionConsumer(Preprocessor &PP,
    518                                                StringRef Filename,
    519                                                unsigned Line,
    520                                                unsigned Column,
    521                                                const CodeCompleteOptions &Opts,
    522                                                raw_ostream &OS) {
    523   if (EnableCodeCompletion(PP, Filename, Line, Column))
    524     return nullptr;
    525 
    526   // Set up the creation routine for code-completion.
    527   return new PrintingCodeCompleteConsumer(Opts, OS);
    528 }
    529 
    530 void CompilerInstance::createSema(TranslationUnitKind TUKind,
    531                                   CodeCompleteConsumer *CompletionConsumer) {
    532   TheSema.reset(new Sema(getPreprocessor(), getASTContext(), getASTConsumer(),
    533                          TUKind, CompletionConsumer));
    534 }
    535 
    536 // Output Files
    537 
    538 void CompilerInstance::addOutputFile(OutputFile &&OutFile) {
    539   assert(OutFile.OS && "Attempt to add empty stream to output list!");
    540   OutputFiles.push_back(std::move(OutFile));
    541 }
    542 
    543 void CompilerInstance::clearOutputFiles(bool EraseFiles) {
    544   for (OutputFile &OF : OutputFiles) {
    545     // Manually close the stream before we rename it.
    546     OF.OS.reset();
    547 
    548     if (!OF.TempFilename.empty()) {
    549       if (EraseFiles) {
    550         llvm::sys::fs::remove(OF.TempFilename);
    551       } else {
    552         SmallString<128> NewOutFile(OF.Filename);
    553 
    554         // If '-working-directory' was passed, the output filename should be
    555         // relative to that.
    556         FileMgr->FixupRelativePath(NewOutFile);
    557         if (std::error_code ec =
    558                 llvm::sys::fs::rename(OF.TempFilename, NewOutFile)) {
    559           getDiagnostics().Report(diag::err_unable_to_rename_temp)
    560             << OF.TempFilename << OF.Filename << ec.message();
    561 
    562           llvm::sys::fs::remove(OF.TempFilename);
    563         }
    564       }
    565     } else if (!OF.Filename.empty() && EraseFiles)
    566       llvm::sys::fs::remove(OF.Filename);
    567 
    568   }
    569   OutputFiles.clear();
    570   NonSeekStream.reset();
    571 }
    572 
    573 raw_pwrite_stream *
    574 CompilerInstance::createDefaultOutputFile(bool Binary, StringRef InFile,
    575                                           StringRef Extension) {
    576   return createOutputFile(getFrontendOpts().OutputFile, Binary,
    577                           /*RemoveFileOnSignal=*/true, InFile, Extension,
    578                           /*UseTemporary=*/true);
    579 }
    580 
    581 llvm::raw_null_ostream *CompilerInstance::createNullOutputFile() {
    582   auto OS = llvm::make_unique<llvm::raw_null_ostream>();
    583   llvm::raw_null_ostream *Ret = OS.get();
    584   addOutputFile(OutputFile("", "", std::move(OS)));
    585   return Ret;
    586 }
    587 
    588 raw_pwrite_stream *
    589 CompilerInstance::createOutputFile(StringRef OutputPath, bool Binary,
    590                                    bool RemoveFileOnSignal, StringRef InFile,
    591                                    StringRef Extension, bool UseTemporary,
    592                                    bool CreateMissingDirectories) {
    593   std::string OutputPathName, TempPathName;
    594   std::error_code EC;
    595   std::unique_ptr<raw_pwrite_stream> OS = createOutputFile(
    596       OutputPath, EC, Binary, RemoveFileOnSignal, InFile, Extension,
    597       UseTemporary, CreateMissingDirectories, &OutputPathName, &TempPathName);
    598   if (!OS) {
    599     getDiagnostics().Report(diag::err_fe_unable_to_open_output) << OutputPath
    600                                                                 << EC.message();
    601     return nullptr;
    602   }
    603 
    604   raw_pwrite_stream *Ret = OS.get();
    605   // Add the output file -- but don't try to remove "-", since this means we are
    606   // using stdin.
    607   addOutputFile(OutputFile((OutputPathName != "-") ? OutputPathName : "",
    608                            TempPathName, std::move(OS)));
    609 
    610   return Ret;
    611 }
    612 
    613 std::unique_ptr<llvm::raw_pwrite_stream> CompilerInstance::createOutputFile(
    614     StringRef OutputPath, std::error_code &Error, bool Binary,
    615     bool RemoveFileOnSignal, StringRef InFile, StringRef Extension,
    616     bool UseTemporary, bool CreateMissingDirectories,
    617     std::string *ResultPathName, std::string *TempPathName) {
    618   assert((!CreateMissingDirectories || UseTemporary) &&
    619          "CreateMissingDirectories is only allowed when using temporary files");
    620 
    621   std::string OutFile, TempFile;
    622   if (!OutputPath.empty()) {
    623     OutFile = OutputPath;
    624   } else if (InFile == "-") {
    625     OutFile = "-";
    626   } else if (!Extension.empty()) {
    627     SmallString<128> Path(InFile);
    628     llvm::sys::path::replace_extension(Path, Extension);
    629     OutFile = Path.str();
    630   } else {
    631     OutFile = "-";
    632   }
    633 
    634   std::unique_ptr<llvm::raw_fd_ostream> OS;
    635   std::string OSFile;
    636 
    637   if (UseTemporary) {
    638     if (OutFile == "-")
    639       UseTemporary = false;
    640     else {
    641       llvm::sys::fs::file_status Status;
    642       llvm::sys::fs::status(OutputPath, Status);
    643       if (llvm::sys::fs::exists(Status)) {
    644         // Fail early if we can't write to the final destination.
    645         if (!llvm::sys::fs::can_write(OutputPath)) {
    646           Error = make_error_code(llvm::errc::operation_not_permitted);
    647           return nullptr;
    648         }
    649 
    650         // Don't use a temporary if the output is a special file. This handles
    651         // things like '-o /dev/null'
    652         if (!llvm::sys::fs::is_regular_file(Status))
    653           UseTemporary = false;
    654       }
    655     }
    656   }
    657 
    658   if (UseTemporary) {
    659     // Create a temporary file.
    660     SmallString<128> TempPath;
    661     TempPath = OutFile;
    662     TempPath += "-%%%%%%%%";
    663     int fd;
    664     std::error_code EC =
    665         llvm::sys::fs::createUniqueFile(TempPath, fd, TempPath);
    666 
    667     if (CreateMissingDirectories &&
    668         EC == llvm::errc::no_such_file_or_directory) {
    669       StringRef Parent = llvm::sys::path::parent_path(OutputPath);
    670       EC = llvm::sys::fs::create_directories(Parent);
    671       if (!EC) {
    672         EC = llvm::sys::fs::createUniqueFile(TempPath, fd, TempPath);
    673       }
    674     }
    675 
    676     if (!EC) {
    677       OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
    678       OSFile = TempFile = TempPath.str();
    679     }
    680     // If we failed to create the temporary, fallback to writing to the file
    681     // directly. This handles the corner case where we cannot write to the
    682     // directory, but can write to the file.
    683   }
    684 
    685   if (!OS) {
    686     OSFile = OutFile;
    687     OS.reset(new llvm::raw_fd_ostream(
    688         OSFile, Error,
    689         (Binary ? llvm::sys::fs::F_None : llvm::sys::fs::F_Text)));
    690     if (Error)
    691       return nullptr;
    692   }
    693 
    694   // Make sure the out stream file gets removed if we crash.
    695   if (RemoveFileOnSignal)
    696     llvm::sys::RemoveFileOnSignal(OSFile);
    697 
    698   if (ResultPathName)
    699     *ResultPathName = OutFile;
    700   if (TempPathName)
    701     *TempPathName = TempFile;
    702 
    703   if (!Binary || OS->supportsSeeking())
    704     return std::move(OS);
    705 
    706   auto B = llvm::make_unique<llvm::buffer_ostream>(*OS);
    707   assert(!NonSeekStream);
    708   NonSeekStream = std::move(OS);
    709   return std::move(B);
    710 }
    711 
    712 // Initialization Utilities
    713 
    714 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input){
    715   return InitializeSourceManager(Input, getDiagnostics(),
    716                                  getFileManager(), getSourceManager(),
    717                                  getFrontendOpts());
    718 }
    719 
    720 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input,
    721                                                DiagnosticsEngine &Diags,
    722                                                FileManager &FileMgr,
    723                                                SourceManager &SourceMgr,
    724                                                const FrontendOptions &Opts) {
    725   SrcMgr::CharacteristicKind
    726     Kind = Input.isSystem() ? SrcMgr::C_System : SrcMgr::C_User;
    727 
    728   if (Input.isBuffer()) {
    729     SourceMgr.setMainFileID(SourceMgr.createFileID(
    730         std::unique_ptr<llvm::MemoryBuffer>(Input.getBuffer()), Kind));
    731     assert(SourceMgr.getMainFileID().isValid() &&
    732            "Couldn't establish MainFileID!");
    733     return true;
    734   }
    735 
    736   StringRef InputFile = Input.getFile();
    737 
    738   // Figure out where to get and map in the main file.
    739   if (InputFile != "-") {
    740     const FileEntry *File = FileMgr.getFile(InputFile, /*OpenFile=*/true);
    741     if (!File) {
    742       Diags.Report(diag::err_fe_error_reading) << InputFile;
    743       return false;
    744     }
    745 
    746     // The natural SourceManager infrastructure can't currently handle named
    747     // pipes, but we would at least like to accept them for the main
    748     // file. Detect them here, read them with the volatile flag so FileMgr will
    749     // pick up the correct size, and simply override their contents as we do for
    750     // STDIN.
    751     if (File->isNamedPipe()) {
    752       auto MB = FileMgr.getBufferForFile(File, /*isVolatile=*/true);
    753       if (MB) {
    754         // Create a new virtual file that will have the correct size.
    755         File = FileMgr.getVirtualFile(InputFile, (*MB)->getBufferSize(), 0);
    756         SourceMgr.overrideFileContents(File, std::move(*MB));
    757       } else {
    758         Diags.Report(diag::err_cannot_open_file) << InputFile
    759                                                  << MB.getError().message();
    760         return false;
    761       }
    762     }
    763 
    764     SourceMgr.setMainFileID(
    765         SourceMgr.createFileID(File, SourceLocation(), Kind));
    766   } else {
    767     llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> SBOrErr =
    768         llvm::MemoryBuffer::getSTDIN();
    769     if (std::error_code EC = SBOrErr.getError()) {
    770       Diags.Report(diag::err_fe_error_reading_stdin) << EC.message();
    771       return false;
    772     }
    773     std::unique_ptr<llvm::MemoryBuffer> SB = std::move(SBOrErr.get());
    774 
    775     const FileEntry *File = FileMgr.getVirtualFile(SB->getBufferIdentifier(),
    776                                                    SB->getBufferSize(), 0);
    777     SourceMgr.setMainFileID(
    778         SourceMgr.createFileID(File, SourceLocation(), Kind));
    779     SourceMgr.overrideFileContents(File, std::move(SB));
    780   }
    781 
    782   assert(SourceMgr.getMainFileID().isValid() &&
    783          "Couldn't establish MainFileID!");
    784   return true;
    785 }
    786 
    787 // High-Level Operations
    788 
    789 bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
    790   assert(hasDiagnostics() && "Diagnostics engine is not initialized!");
    791   assert(!getFrontendOpts().ShowHelp && "Client must handle '-help'!");
    792   assert(!getFrontendOpts().ShowVersion && "Client must handle '-version'!");
    793 
    794   // FIXME: Take this as an argument, once all the APIs we used have moved to
    795   // taking it as an input instead of hard-coding llvm::errs.
    796   raw_ostream &OS = llvm::errs();
    797 
    798   // Create the target instance.
    799   setTarget(TargetInfo::CreateTargetInfo(getDiagnostics(),
    800                                          getInvocation().TargetOpts));
    801   if (!hasTarget())
    802     return false;
    803 
    804   // Create TargetInfo for the other side of CUDA compilation.
    805   if (getLangOpts().CUDA && !getFrontendOpts().AuxTriple.empty()) {
    806     std::shared_ptr<TargetOptions> TO(new TargetOptions);
    807     TO->Triple = getFrontendOpts().AuxTriple;
    808     setAuxTarget(TargetInfo::CreateTargetInfo(getDiagnostics(), TO));
    809   }
    810 
    811   // Inform the target of the language options.
    812   //
    813   // FIXME: We shouldn't need to do this, the target should be immutable once
    814   // created. This complexity should be lifted elsewhere.
    815   getTarget().adjust(getLangOpts());
    816 
    817   // rewriter project will change target built-in bool type from its default.
    818   if (getFrontendOpts().ProgramAction == frontend::RewriteObjC)
    819     getTarget().noSignedCharForObjCBool();
    820 
    821   // Validate/process some options.
    822   if (getHeaderSearchOpts().Verbose)
    823     OS << "clang -cc1 version " CLANG_VERSION_STRING
    824        << " based upon " << BACKEND_PACKAGE_STRING
    825        << " default target " << llvm::sys::getDefaultTargetTriple() << "\n";
    826 
    827   if (getFrontendOpts().ShowTimers)
    828     createFrontendTimer();
    829 
    830   if (getFrontendOpts().ShowStats)
    831     llvm::EnableStatistics();
    832 
    833   for (const FrontendInputFile &FIF : getFrontendOpts().Inputs) {
    834     // Reset the ID tables if we are reusing the SourceManager and parsing
    835     // regular files.
    836     if (hasSourceManager() && !Act.isModelParsingAction())
    837       getSourceManager().clearIDTables();
    838 
    839     if (Act.BeginSourceFile(*this, FIF)) {
    840       Act.Execute();
    841       Act.EndSourceFile();
    842     }
    843   }
    844 
    845   // Notify the diagnostic client that all files were processed.
    846   getDiagnostics().getClient()->finish();
    847 
    848   if (getDiagnosticOpts().ShowCarets) {
    849     // We can have multiple diagnostics sharing one diagnostic client.
    850     // Get the total number of warnings/errors from the client.
    851     unsigned NumWarnings = getDiagnostics().getClient()->getNumWarnings();
    852     unsigned NumErrors = getDiagnostics().getClient()->getNumErrors();
    853 
    854     if (NumWarnings)
    855       OS << NumWarnings << " warning" << (NumWarnings == 1 ? "" : "s");
    856     if (NumWarnings && NumErrors)
    857       OS << " and ";
    858     if (NumErrors)
    859       OS << NumErrors << " error" << (NumErrors == 1 ? "" : "s");
    860     if (NumWarnings || NumErrors)
    861       OS << " generated.\n";
    862   }
    863 
    864   if (getFrontendOpts().ShowStats && hasFileManager()) {
    865     getFileManager().PrintStats();
    866     OS << "\n";
    867   }
    868 
    869   return !getDiagnostics().getClient()->getNumErrors();
    870 }
    871 
    872 /// \brief Determine the appropriate source input kind based on language
    873 /// options.
    874 static InputKind getSourceInputKindFromOptions(const LangOptions &LangOpts) {
    875   if (LangOpts.OpenCL)
    876     return IK_OpenCL;
    877   if (LangOpts.CUDA)
    878     return IK_CUDA;
    879   if (LangOpts.ObjC1)
    880     return LangOpts.CPlusPlus? IK_ObjCXX : IK_ObjC;
    881   return LangOpts.CPlusPlus? IK_CXX : IK_C;
    882 }
    883 
    884 /// \brief Compile a module file for the given module, using the options
    885 /// provided by the importing compiler instance. Returns true if the module
    886 /// was built without errors.
    887 static bool compileModuleImpl(CompilerInstance &ImportingInstance,
    888                               SourceLocation ImportLoc,
    889                               Module *Module,
    890                               StringRef ModuleFileName) {
    891   ModuleMap &ModMap
    892     = ImportingInstance.getPreprocessor().getHeaderSearchInfo().getModuleMap();
    893 
    894   // Construct a compiler invocation for creating this module.
    895   IntrusiveRefCntPtr<CompilerInvocation> Invocation
    896     (new CompilerInvocation(ImportingInstance.getInvocation()));
    897 
    898   PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
    899 
    900   // For any options that aren't intended to affect how a module is built,
    901   // reset them to their default values.
    902   Invocation->getLangOpts()->resetNonModularOptions();
    903   PPOpts.resetNonModularOptions();
    904 
    905   // Remove any macro definitions that are explicitly ignored by the module.
    906   // They aren't supposed to affect how the module is built anyway.
    907   const HeaderSearchOptions &HSOpts = Invocation->getHeaderSearchOpts();
    908   PPOpts.Macros.erase(
    909       std::remove_if(PPOpts.Macros.begin(), PPOpts.Macros.end(),
    910                      [&HSOpts](const std::pair<std::string, bool> &def) {
    911         StringRef MacroDef = def.first;
    912         return HSOpts.ModulesIgnoreMacros.count(MacroDef.split('=').first) > 0;
    913       }),
    914       PPOpts.Macros.end());
    915 
    916   // Note the name of the module we're building.
    917   Invocation->getLangOpts()->CurrentModule = Module->getTopLevelModuleName();
    918 
    919   // Make sure that the failed-module structure has been allocated in
    920   // the importing instance, and propagate the pointer to the newly-created
    921   // instance.
    922   PreprocessorOptions &ImportingPPOpts
    923     = ImportingInstance.getInvocation().getPreprocessorOpts();
    924   if (!ImportingPPOpts.FailedModules)
    925     ImportingPPOpts.FailedModules = new PreprocessorOptions::FailedModulesSet;
    926   PPOpts.FailedModules = ImportingPPOpts.FailedModules;
    927 
    928   // If there is a module map file, build the module using the module map.
    929   // Set up the inputs/outputs so that we build the module from its umbrella
    930   // header.
    931   FrontendOptions &FrontendOpts = Invocation->getFrontendOpts();
    932   FrontendOpts.OutputFile = ModuleFileName.str();
    933   FrontendOpts.DisableFree = false;
    934   FrontendOpts.GenerateGlobalModuleIndex = false;
    935   FrontendOpts.BuildingImplicitModule = true;
    936   FrontendOpts.Inputs.clear();
    937   InputKind IK = getSourceInputKindFromOptions(*Invocation->getLangOpts());
    938 
    939   // Don't free the remapped file buffers; they are owned by our caller.
    940   PPOpts.RetainRemappedFileBuffers = true;
    941 
    942   Invocation->getDiagnosticOpts().VerifyDiagnostics = 0;
    943   assert(ImportingInstance.getInvocation().getModuleHash() ==
    944          Invocation->getModuleHash() && "Module hash mismatch!");
    945 
    946   // Construct a compiler instance that will be used to actually create the
    947   // module.
    948   CompilerInstance Instance(ImportingInstance.getPCHContainerOperations(),
    949                             /*BuildingModule=*/true);
    950   Instance.setInvocation(&*Invocation);
    951 
    952   Instance.createDiagnostics(new ForwardingDiagnosticConsumer(
    953                                    ImportingInstance.getDiagnosticClient()),
    954                              /*ShouldOwnClient=*/true);
    955 
    956   Instance.setVirtualFileSystem(&ImportingInstance.getVirtualFileSystem());
    957 
    958   // Note that this module is part of the module build stack, so that we
    959   // can detect cycles in the module graph.
    960   Instance.setFileManager(&ImportingInstance.getFileManager());
    961   Instance.createSourceManager(Instance.getFileManager());
    962   SourceManager &SourceMgr = Instance.getSourceManager();
    963   SourceMgr.setModuleBuildStack(
    964     ImportingInstance.getSourceManager().getModuleBuildStack());
    965   SourceMgr.pushModuleBuildStack(Module->getTopLevelModuleName(),
    966     FullSourceLoc(ImportLoc, ImportingInstance.getSourceManager()));
    967 
    968   // If we're collecting module dependencies, we need to share a collector
    969   // between all of the module CompilerInstances. Other than that, we don't
    970   // want to produce any dependency output from the module build.
    971   Instance.setModuleDepCollector(ImportingInstance.getModuleDepCollector());
    972   Invocation->getDependencyOutputOpts() = DependencyOutputOptions();
    973 
    974   // Get or create the module map that we'll use to build this module.
    975   std::string InferredModuleMapContent;
    976   if (const FileEntry *ModuleMapFile =
    977           ModMap.getContainingModuleMapFile(Module)) {
    978     // Use the module map where this module resides.
    979     FrontendOpts.Inputs.emplace_back(ModuleMapFile->getName(), IK);
    980   } else {
    981     SmallString<128> FakeModuleMapFile(Module->Directory->getName());
    982     llvm::sys::path::append(FakeModuleMapFile, "__inferred_module.map");
    983     FrontendOpts.Inputs.emplace_back(FakeModuleMapFile, IK);
    984 
    985     llvm::raw_string_ostream OS(InferredModuleMapContent);
    986     Module->print(OS);
    987     OS.flush();
    988 
    989     std::unique_ptr<llvm::MemoryBuffer> ModuleMapBuffer =
    990         llvm::MemoryBuffer::getMemBuffer(InferredModuleMapContent);
    991     ModuleMapFile = Instance.getFileManager().getVirtualFile(
    992         FakeModuleMapFile, InferredModuleMapContent.size(), 0);
    993     SourceMgr.overrideFileContents(ModuleMapFile, std::move(ModuleMapBuffer));
    994   }
    995 
    996   // Construct a module-generating action. Passing through the module map is
    997   // safe because the FileManager is shared between the compiler instances.
    998   GenerateModuleAction CreateModuleAction(
    999       ModMap.getModuleMapFileForUniquing(Module), Module->IsSystem);
   1000 
   1001   ImportingInstance.getDiagnostics().Report(ImportLoc,
   1002                                             diag::remark_module_build)
   1003     << Module->Name << ModuleFileName;
   1004 
   1005   // Execute the action to actually build the module in-place. Use a separate
   1006   // thread so that we get a stack large enough.
   1007   const unsigned ThreadStackSize = 8 << 20;
   1008   llvm::CrashRecoveryContext CRC;
   1009   CRC.RunSafelyOnThread([&]() { Instance.ExecuteAction(CreateModuleAction); },
   1010                         ThreadStackSize);
   1011 
   1012   ImportingInstance.getDiagnostics().Report(ImportLoc,
   1013                                             diag::remark_module_build_done)
   1014     << Module->Name;
   1015 
   1016   // Delete the temporary module map file.
   1017   // FIXME: Even though we're executing under crash protection, it would still
   1018   // be nice to do this with RemoveFileOnSignal when we can. However, that
   1019   // doesn't make sense for all clients, so clean this up manually.
   1020   Instance.clearOutputFiles(/*EraseFiles=*/true);
   1021 
   1022   // We've rebuilt a module. If we're allowed to generate or update the global
   1023   // module index, record that fact in the importing compiler instance.
   1024   if (ImportingInstance.getFrontendOpts().GenerateGlobalModuleIndex) {
   1025     ImportingInstance.setBuildGlobalModuleIndex(true);
   1026   }
   1027 
   1028   return !Instance.getDiagnostics().hasErrorOccurred();
   1029 }
   1030 
   1031 static bool compileAndLoadModule(CompilerInstance &ImportingInstance,
   1032                                  SourceLocation ImportLoc,
   1033                                  SourceLocation ModuleNameLoc, Module *Module,
   1034                                  StringRef ModuleFileName) {
   1035   DiagnosticsEngine &Diags = ImportingInstance.getDiagnostics();
   1036 
   1037   auto diagnoseBuildFailure = [&] {
   1038     Diags.Report(ModuleNameLoc, diag::err_module_not_built)
   1039         << Module->Name << SourceRange(ImportLoc, ModuleNameLoc);
   1040   };
   1041 
   1042   // FIXME: have LockFileManager return an error_code so that we can
   1043   // avoid the mkdir when the directory already exists.
   1044   StringRef Dir = llvm::sys::path::parent_path(ModuleFileName);
   1045   llvm::sys::fs::create_directories(Dir);
   1046 
   1047   while (1) {
   1048     unsigned ModuleLoadCapabilities = ASTReader::ARR_Missing;
   1049     llvm::LockFileManager Locked(ModuleFileName);
   1050     switch (Locked) {
   1051     case llvm::LockFileManager::LFS_Error:
   1052       Diags.Report(ModuleNameLoc, diag::err_module_lock_failure)
   1053           << Module->Name;
   1054       return false;
   1055 
   1056     case llvm::LockFileManager::LFS_Owned:
   1057       // We're responsible for building the module ourselves.
   1058       if (!compileModuleImpl(ImportingInstance, ModuleNameLoc, Module,
   1059                              ModuleFileName)) {
   1060         diagnoseBuildFailure();
   1061         return false;
   1062       }
   1063       break;
   1064 
   1065     case llvm::LockFileManager::LFS_Shared:
   1066       // Someone else is responsible for building the module. Wait for them to
   1067       // finish.
   1068       switch (Locked.waitForUnlock()) {
   1069       case llvm::LockFileManager::Res_Success:
   1070         ModuleLoadCapabilities |= ASTReader::ARR_OutOfDate;
   1071         break;
   1072       case llvm::LockFileManager::Res_OwnerDied:
   1073         continue; // try again to get the lock.
   1074       case llvm::LockFileManager::Res_Timeout:
   1075         Diags.Report(ModuleNameLoc, diag::err_module_lock_timeout)
   1076             << Module->Name;
   1077         // Clear the lock file so that future invokations can make progress.
   1078         Locked.unsafeRemoveLockFile();
   1079         return false;
   1080       }
   1081       break;
   1082     }
   1083 
   1084     // Try to read the module file, now that we've compiled it.
   1085     ASTReader::ASTReadResult ReadResult =
   1086         ImportingInstance.getModuleManager()->ReadAST(
   1087             ModuleFileName, serialization::MK_ImplicitModule, ImportLoc,
   1088             ModuleLoadCapabilities);
   1089 
   1090     if (ReadResult == ASTReader::OutOfDate &&
   1091         Locked == llvm::LockFileManager::LFS_Shared) {
   1092       // The module may be out of date in the presence of file system races,
   1093       // or if one of its imports depends on header search paths that are not
   1094       // consistent with this ImportingInstance.  Try again...
   1095       continue;
   1096     } else if (ReadResult == ASTReader::Missing) {
   1097       diagnoseBuildFailure();
   1098     } else if (ReadResult != ASTReader::Success &&
   1099                !Diags.hasErrorOccurred()) {
   1100       // The ASTReader didn't diagnose the error, so conservatively report it.
   1101       diagnoseBuildFailure();
   1102     }
   1103     return ReadResult == ASTReader::Success;
   1104   }
   1105 }
   1106 
   1107 /// \brief Diagnose differences between the current definition of the given
   1108 /// configuration macro and the definition provided on the command line.
   1109 static void checkConfigMacro(Preprocessor &PP, StringRef ConfigMacro,
   1110                              Module *Mod, SourceLocation ImportLoc) {
   1111   IdentifierInfo *Id = PP.getIdentifierInfo(ConfigMacro);
   1112   SourceManager &SourceMgr = PP.getSourceManager();
   1113 
   1114   // If this identifier has never had a macro definition, then it could
   1115   // not have changed.
   1116   if (!Id->hadMacroDefinition())
   1117     return;
   1118   auto *LatestLocalMD = PP.getLocalMacroDirectiveHistory(Id);
   1119 
   1120   // Find the macro definition from the command line.
   1121   MacroInfo *CmdLineDefinition = nullptr;
   1122   for (auto *MD = LatestLocalMD; MD; MD = MD->getPrevious()) {
   1123     // We only care about the predefines buffer.
   1124     FileID FID = SourceMgr.getFileID(MD->getLocation());
   1125     if (FID.isInvalid() || FID != PP.getPredefinesFileID())
   1126       continue;
   1127     if (auto *DMD = dyn_cast<DefMacroDirective>(MD))
   1128       CmdLineDefinition = DMD->getMacroInfo();
   1129     break;
   1130   }
   1131 
   1132   auto *CurrentDefinition = PP.getMacroInfo(Id);
   1133   if (CurrentDefinition == CmdLineDefinition) {
   1134     // Macro matches. Nothing to do.
   1135   } else if (!CurrentDefinition) {
   1136     // This macro was defined on the command line, then #undef'd later.
   1137     // Complain.
   1138     PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
   1139       << true << ConfigMacro << Mod->getFullModuleName();
   1140     auto LatestDef = LatestLocalMD->getDefinition();
   1141     assert(LatestDef.isUndefined() &&
   1142            "predefined macro went away with no #undef?");
   1143     PP.Diag(LatestDef.getUndefLocation(), diag::note_module_def_undef_here)
   1144       << true;
   1145     return;
   1146   } else if (!CmdLineDefinition) {
   1147     // There was no definition for this macro in the predefines buffer,
   1148     // but there was a local definition. Complain.
   1149     PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
   1150       << false << ConfigMacro << Mod->getFullModuleName();
   1151     PP.Diag(CurrentDefinition->getDefinitionLoc(),
   1152             diag::note_module_def_undef_here)
   1153       << false;
   1154   } else if (!CurrentDefinition->isIdenticalTo(*CmdLineDefinition, PP,
   1155                                                /*Syntactically=*/true)) {
   1156     // The macro definitions differ.
   1157     PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
   1158       << false << ConfigMacro << Mod->getFullModuleName();
   1159     PP.Diag(CurrentDefinition->getDefinitionLoc(),
   1160             diag::note_module_def_undef_here)
   1161       << false;
   1162   }
   1163 }
   1164 
   1165 /// \brief Write a new timestamp file with the given path.
   1166 static void writeTimestampFile(StringRef TimestampFile) {
   1167   std::error_code EC;
   1168   llvm::raw_fd_ostream Out(TimestampFile.str(), EC, llvm::sys::fs::F_None);
   1169 }
   1170 
   1171 /// \brief Prune the module cache of modules that haven't been accessed in
   1172 /// a long time.
   1173 static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
   1174   struct stat StatBuf;
   1175   llvm::SmallString<128> TimestampFile;
   1176   TimestampFile = HSOpts.ModuleCachePath;
   1177   assert(!TimestampFile.empty());
   1178   llvm::sys::path::append(TimestampFile, "modules.timestamp");
   1179 
   1180   // Try to stat() the timestamp file.
   1181   if (::stat(TimestampFile.c_str(), &StatBuf)) {
   1182     // If the timestamp file wasn't there, create one now.
   1183     if (errno == ENOENT) {
   1184       writeTimestampFile(TimestampFile);
   1185     }
   1186     return;
   1187   }
   1188 
   1189   // Check whether the time stamp is older than our pruning interval.
   1190   // If not, do nothing.
   1191   time_t TimeStampModTime = StatBuf.st_mtime;
   1192   time_t CurrentTime = time(nullptr);
   1193   if (CurrentTime - TimeStampModTime <= time_t(HSOpts.ModuleCachePruneInterval))
   1194     return;
   1195 
   1196   // Write a new timestamp file so that nobody else attempts to prune.
   1197   // There is a benign race condition here, if two Clang instances happen to
   1198   // notice at the same time that the timestamp is out-of-date.
   1199   writeTimestampFile(TimestampFile);
   1200 
   1201   // Walk the entire module cache, looking for unused module files and module
   1202   // indices.
   1203   std::error_code EC;
   1204   SmallString<128> ModuleCachePathNative;
   1205   llvm::sys::path::native(HSOpts.ModuleCachePath, ModuleCachePathNative);
   1206   for (llvm::sys::fs::directory_iterator Dir(ModuleCachePathNative, EC), DirEnd;
   1207        Dir != DirEnd && !EC; Dir.increment(EC)) {
   1208     // If we don't have a directory, there's nothing to look into.
   1209     if (!llvm::sys::fs::is_directory(Dir->path()))
   1210       continue;
   1211 
   1212     // Walk all of the files within this directory.
   1213     for (llvm::sys::fs::directory_iterator File(Dir->path(), EC), FileEnd;
   1214          File != FileEnd && !EC; File.increment(EC)) {
   1215       // We only care about module and global module index files.
   1216       StringRef Extension = llvm::sys::path::extension(File->path());
   1217       if (Extension != ".pcm" && Extension != ".timestamp" &&
   1218           llvm::sys::path::filename(File->path()) != "modules.idx")
   1219         continue;
   1220 
   1221       // Look at this file. If we can't stat it, there's nothing interesting
   1222       // there.
   1223       if (::stat(File->path().c_str(), &StatBuf))
   1224         continue;
   1225 
   1226       // If the file has been used recently enough, leave it there.
   1227       time_t FileAccessTime = StatBuf.st_atime;
   1228       if (CurrentTime - FileAccessTime <=
   1229               time_t(HSOpts.ModuleCachePruneAfter)) {
   1230         continue;
   1231       }
   1232 
   1233       // Remove the file.
   1234       llvm::sys::fs::remove(File->path());
   1235 
   1236       // Remove the timestamp file.
   1237       std::string TimpestampFilename = File->path() + ".timestamp";
   1238       llvm::sys::fs::remove(TimpestampFilename);
   1239     }
   1240 
   1241     // If we removed all of the files in the directory, remove the directory
   1242     // itself.
   1243     if (llvm::sys::fs::directory_iterator(Dir->path(), EC) ==
   1244             llvm::sys::fs::directory_iterator() && !EC)
   1245       llvm::sys::fs::remove(Dir->path());
   1246   }
   1247 }
   1248 
   1249 void CompilerInstance::createModuleManager() {
   1250   if (!ModuleManager) {
   1251     if (!hasASTContext())
   1252       createASTContext();
   1253 
   1254     // If we're implicitly building modules but not currently recursively
   1255     // building a module, check whether we need to prune the module cache.
   1256     if (getSourceManager().getModuleBuildStack().empty() &&
   1257         !getPreprocessor().getHeaderSearchInfo().getModuleCachePath().empty() &&
   1258         getHeaderSearchOpts().ModuleCachePruneInterval > 0 &&
   1259         getHeaderSearchOpts().ModuleCachePruneAfter > 0) {
   1260       pruneModuleCache(getHeaderSearchOpts());
   1261     }
   1262 
   1263     HeaderSearchOptions &HSOpts = getHeaderSearchOpts();
   1264     std::string Sysroot = HSOpts.Sysroot;
   1265     const PreprocessorOptions &PPOpts = getPreprocessorOpts();
   1266     std::unique_ptr<llvm::Timer> ReadTimer;
   1267     if (FrontendTimerGroup)
   1268       ReadTimer = llvm::make_unique<llvm::Timer>("Reading modules",
   1269                                                  *FrontendTimerGroup);
   1270     ModuleManager = new ASTReader(
   1271         getPreprocessor(), getASTContext(), getPCHContainerReader(),
   1272         getFrontendOpts().ModuleFileExtensions,
   1273         Sysroot.empty() ? "" : Sysroot.c_str(), PPOpts.DisablePCHValidation,
   1274         /*AllowASTWithCompilerErrors=*/false,
   1275         /*AllowConfigurationMismatch=*/false,
   1276         HSOpts.ModulesValidateSystemHeaders,
   1277         getFrontendOpts().UseGlobalModuleIndex,
   1278         std::move(ReadTimer));
   1279     if (hasASTConsumer()) {
   1280       ModuleManager->setDeserializationListener(
   1281         getASTConsumer().GetASTDeserializationListener());
   1282       getASTContext().setASTMutationListener(
   1283         getASTConsumer().GetASTMutationListener());
   1284     }
   1285     getASTContext().setExternalSource(ModuleManager);
   1286     if (hasSema())
   1287       ModuleManager->InitializeSema(getSema());
   1288     if (hasASTConsumer())
   1289       ModuleManager->StartTranslationUnit(&getASTConsumer());
   1290 
   1291     if (TheDependencyFileGenerator)
   1292       TheDependencyFileGenerator->AttachToASTReader(*ModuleManager);
   1293     if (ModuleDepCollector)
   1294       ModuleDepCollector->attachToASTReader(*ModuleManager);
   1295     for (auto &Listener : DependencyCollectors)
   1296       Listener->attachToASTReader(*ModuleManager);
   1297   }
   1298 }
   1299 
   1300 bool CompilerInstance::loadModuleFile(StringRef FileName) {
   1301   llvm::Timer Timer;
   1302   if (FrontendTimerGroup)
   1303     Timer.init("Preloading " + FileName.str(), *FrontendTimerGroup);
   1304   llvm::TimeRegion TimeLoading(FrontendTimerGroup ? &Timer : nullptr);
   1305 
   1306   // Helper to recursively read the module names for all modules we're adding.
   1307   // We mark these as known and redirect any attempt to load that module to
   1308   // the files we were handed.
   1309   struct ReadModuleNames : ASTReaderListener {
   1310     CompilerInstance &CI;
   1311     llvm::SmallVector<IdentifierInfo*, 8> LoadedModules;
   1312 
   1313     ReadModuleNames(CompilerInstance &CI) : CI(CI) {}
   1314 
   1315     void ReadModuleName(StringRef ModuleName) override {
   1316       LoadedModules.push_back(
   1317           CI.getPreprocessor().getIdentifierInfo(ModuleName));
   1318     }
   1319 
   1320     void registerAll() {
   1321       for (auto *II : LoadedModules) {
   1322         CI.KnownModules[II] = CI.getPreprocessor()
   1323                                   .getHeaderSearchInfo()
   1324                                   .getModuleMap()
   1325                                   .findModule(II->getName());
   1326       }
   1327       LoadedModules.clear();
   1328     }
   1329 
   1330     void markAllUnavailable() {
   1331       for (auto *II : LoadedModules) {
   1332         if (Module *M = CI.getPreprocessor()
   1333                             .getHeaderSearchInfo()
   1334                             .getModuleMap()
   1335                             .findModule(II->getName()))
   1336           M->HasIncompatibleModuleFile = true;
   1337       }
   1338       LoadedModules.clear();
   1339     }
   1340   };
   1341 
   1342   // If we don't already have an ASTReader, create one now.
   1343   if (!ModuleManager)
   1344     createModuleManager();
   1345 
   1346   auto Listener = llvm::make_unique<ReadModuleNames>(*this);
   1347   auto &ListenerRef = *Listener;
   1348   ASTReader::ListenerScope ReadModuleNamesListener(*ModuleManager,
   1349                                                    std::move(Listener));
   1350 
   1351   // Try to load the module file.
   1352   switch (ModuleManager->ReadAST(FileName, serialization::MK_ExplicitModule,
   1353                                  SourceLocation(),
   1354                                  ASTReader::ARR_ConfigurationMismatch)) {
   1355   case ASTReader::Success:
   1356     // We successfully loaded the module file; remember the set of provided
   1357     // modules so that we don't try to load implicit modules for them.
   1358     ListenerRef.registerAll();
   1359     return true;
   1360 
   1361   case ASTReader::ConfigurationMismatch:
   1362     // Ignore unusable module files.
   1363     getDiagnostics().Report(SourceLocation(), diag::warn_module_config_mismatch)
   1364         << FileName;
   1365     // All modules provided by any files we tried and failed to load are now
   1366     // unavailable; includes of those modules should now be handled textually.
   1367     ListenerRef.markAllUnavailable();
   1368     return true;
   1369 
   1370   default:
   1371     return false;
   1372   }
   1373 }
   1374 
   1375 ModuleLoadResult
   1376 CompilerInstance::loadModule(SourceLocation ImportLoc,
   1377                              ModuleIdPath Path,
   1378                              Module::NameVisibilityKind Visibility,
   1379                              bool IsInclusionDirective) {
   1380   // Determine what file we're searching from.
   1381   StringRef ModuleName = Path[0].first->getName();
   1382   SourceLocation ModuleNameLoc = Path[0].second;
   1383 
   1384   // If we've already handled this import, just return the cached result.
   1385   // This one-element cache is important to eliminate redundant diagnostics
   1386   // when both the preprocessor and parser see the same import declaration.
   1387   if (ImportLoc.isValid() && LastModuleImportLoc == ImportLoc) {
   1388     // Make the named module visible.
   1389     if (LastModuleImportResult && ModuleName != getLangOpts().CurrentModule &&
   1390         ModuleName != getLangOpts().ImplementationOfModule)
   1391       ModuleManager->makeModuleVisible(LastModuleImportResult, Visibility,
   1392                                        ImportLoc);
   1393     return LastModuleImportResult;
   1394   }
   1395 
   1396   clang::Module *Module = nullptr;
   1397 
   1398   // If we don't already have information on this module, load the module now.
   1399   llvm::DenseMap<const IdentifierInfo *, clang::Module *>::iterator Known
   1400     = KnownModules.find(Path[0].first);
   1401   if (Known != KnownModules.end()) {
   1402     // Retrieve the cached top-level module.
   1403     Module = Known->second;
   1404   } else if (ModuleName == getLangOpts().CurrentModule ||
   1405              ModuleName == getLangOpts().ImplementationOfModule) {
   1406     // This is the module we're building.
   1407     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
   1408     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
   1409   } else {
   1410     // Search for a module with the given name.
   1411     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
   1412     if (!Module) {
   1413       getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_found)
   1414       << ModuleName
   1415       << SourceRange(ImportLoc, ModuleNameLoc);
   1416       ModuleBuildFailed = true;
   1417       return ModuleLoadResult();
   1418     }
   1419 
   1420     std::string ModuleFileName =
   1421         PP->getHeaderSearchInfo().getModuleFileName(Module);
   1422     if (ModuleFileName.empty()) {
   1423       if (Module->HasIncompatibleModuleFile) {
   1424         // We tried and failed to load a module file for this module. Fall
   1425         // back to textual inclusion for its headers.
   1426         return ModuleLoadResult(nullptr, /*missingExpected*/true);
   1427       }
   1428 
   1429       getDiagnostics().Report(ModuleNameLoc, diag::err_module_build_disabled)
   1430           << ModuleName;
   1431       ModuleBuildFailed = true;
   1432       return ModuleLoadResult();
   1433     }
   1434 
   1435     // If we don't already have an ASTReader, create one now.
   1436     if (!ModuleManager)
   1437       createModuleManager();
   1438 
   1439     llvm::Timer Timer;
   1440     if (FrontendTimerGroup)
   1441       Timer.init("Loading " + ModuleFileName, *FrontendTimerGroup);
   1442     llvm::TimeRegion TimeLoading(FrontendTimerGroup ? &Timer : nullptr);
   1443 
   1444     // Try to load the module file.
   1445     unsigned ARRFlags = ASTReader::ARR_OutOfDate | ASTReader::ARR_Missing;
   1446     switch (ModuleManager->ReadAST(ModuleFileName,
   1447                                    serialization::MK_ImplicitModule,
   1448                                    ImportLoc, ARRFlags)) {
   1449     case ASTReader::Success:
   1450       break;
   1451 
   1452     case ASTReader::OutOfDate:
   1453     case ASTReader::Missing: {
   1454       // The module file is missing or out-of-date. Build it.
   1455       assert(Module && "missing module file");
   1456       // Check whether there is a cycle in the module graph.
   1457       ModuleBuildStack ModPath = getSourceManager().getModuleBuildStack();
   1458       ModuleBuildStack::iterator Pos = ModPath.begin(), PosEnd = ModPath.end();
   1459       for (; Pos != PosEnd; ++Pos) {
   1460         if (Pos->first == ModuleName)
   1461           break;
   1462       }
   1463 
   1464       if (Pos != PosEnd) {
   1465         SmallString<256> CyclePath;
   1466         for (; Pos != PosEnd; ++Pos) {
   1467           CyclePath += Pos->first;
   1468           CyclePath += " -> ";
   1469         }
   1470         CyclePath += ModuleName;
   1471 
   1472         getDiagnostics().Report(ModuleNameLoc, diag::err_module_cycle)
   1473           << ModuleName << CyclePath;
   1474         return ModuleLoadResult();
   1475       }
   1476 
   1477       // Check whether we have already attempted to build this module (but
   1478       // failed).
   1479       if (getPreprocessorOpts().FailedModules &&
   1480           getPreprocessorOpts().FailedModules->hasAlreadyFailed(ModuleName)) {
   1481         getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_built)
   1482           << ModuleName
   1483           << SourceRange(ImportLoc, ModuleNameLoc);
   1484         ModuleBuildFailed = true;
   1485         return ModuleLoadResult();
   1486       }
   1487 
   1488       // Try to compile and then load the module.
   1489       if (!compileAndLoadModule(*this, ImportLoc, ModuleNameLoc, Module,
   1490                                 ModuleFileName)) {
   1491         assert(getDiagnostics().hasErrorOccurred() &&
   1492                "undiagnosed error in compileAndLoadModule");
   1493         if (getPreprocessorOpts().FailedModules)
   1494           getPreprocessorOpts().FailedModules->addFailed(ModuleName);
   1495         KnownModules[Path[0].first] = nullptr;
   1496         ModuleBuildFailed = true;
   1497         return ModuleLoadResult();
   1498       }
   1499 
   1500       // Okay, we've rebuilt and now loaded the module.
   1501       break;
   1502     }
   1503 
   1504     case ASTReader::VersionMismatch:
   1505     case ASTReader::ConfigurationMismatch:
   1506     case ASTReader::HadErrors:
   1507       ModuleLoader::HadFatalFailure = true;
   1508       // FIXME: The ASTReader will already have complained, but can we shoehorn
   1509       // that diagnostic information into a more useful form?
   1510       KnownModules[Path[0].first] = nullptr;
   1511       return ModuleLoadResult();
   1512 
   1513     case ASTReader::Failure:
   1514       ModuleLoader::HadFatalFailure = true;
   1515       // Already complained, but note now that we failed.
   1516       KnownModules[Path[0].first] = nullptr;
   1517       ModuleBuildFailed = true;
   1518       return ModuleLoadResult();
   1519     }
   1520 
   1521     // Cache the result of this top-level module lookup for later.
   1522     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
   1523   }
   1524 
   1525   // If we never found the module, fail.
   1526   if (!Module)
   1527     return ModuleLoadResult();
   1528 
   1529   // Verify that the rest of the module path actually corresponds to
   1530   // a submodule.
   1531   if (Path.size() > 1) {
   1532     for (unsigned I = 1, N = Path.size(); I != N; ++I) {
   1533       StringRef Name = Path[I].first->getName();
   1534       clang::Module *Sub = Module->findSubmodule(Name);
   1535 
   1536       if (!Sub) {
   1537         // Attempt to perform typo correction to find a module name that works.
   1538         SmallVector<StringRef, 2> Best;
   1539         unsigned BestEditDistance = (std::numeric_limits<unsigned>::max)();
   1540 
   1541         for (clang::Module::submodule_iterator J = Module->submodule_begin(),
   1542                                             JEnd = Module->submodule_end();
   1543              J != JEnd; ++J) {
   1544           unsigned ED = Name.edit_distance((*J)->Name,
   1545                                            /*AllowReplacements=*/true,
   1546                                            BestEditDistance);
   1547           if (ED <= BestEditDistance) {
   1548             if (ED < BestEditDistance) {
   1549               Best.clear();
   1550               BestEditDistance = ED;
   1551             }
   1552 
   1553             Best.push_back((*J)->Name);
   1554           }
   1555         }
   1556 
   1557         // If there was a clear winner, user it.
   1558         if (Best.size() == 1) {
   1559           getDiagnostics().Report(Path[I].second,
   1560                                   diag::err_no_submodule_suggest)
   1561             << Path[I].first << Module->getFullModuleName() << Best[0]
   1562             << SourceRange(Path[0].second, Path[I-1].second)
   1563             << FixItHint::CreateReplacement(SourceRange(Path[I].second),
   1564                                             Best[0]);
   1565 
   1566           Sub = Module->findSubmodule(Best[0]);
   1567         }
   1568       }
   1569 
   1570       if (!Sub) {
   1571         // No submodule by this name. Complain, and don't look for further
   1572         // submodules.
   1573         getDiagnostics().Report(Path[I].second, diag::err_no_submodule)
   1574           << Path[I].first << Module->getFullModuleName()
   1575           << SourceRange(Path[0].second, Path[I-1].second);
   1576         break;
   1577       }
   1578 
   1579       Module = Sub;
   1580     }
   1581   }
   1582 
   1583   // Don't make the module visible if we are in the implementation.
   1584   if (ModuleName == getLangOpts().ImplementationOfModule)
   1585     return ModuleLoadResult(Module, false);
   1586 
   1587   // Make the named module visible, if it's not already part of the module
   1588   // we are parsing.
   1589   if (ModuleName != getLangOpts().CurrentModule) {
   1590     if (!Module->IsFromModuleFile) {
   1591       // We have an umbrella header or directory that doesn't actually include
   1592       // all of the headers within the directory it covers. Complain about
   1593       // this missing submodule and recover by forgetting that we ever saw
   1594       // this submodule.
   1595       // FIXME: Should we detect this at module load time? It seems fairly
   1596       // expensive (and rare).
   1597       getDiagnostics().Report(ImportLoc, diag::warn_missing_submodule)
   1598         << Module->getFullModuleName()
   1599         << SourceRange(Path.front().second, Path.back().second);
   1600 
   1601       return ModuleLoadResult(nullptr, true);
   1602     }
   1603 
   1604     // Check whether this module is available.
   1605     clang::Module::Requirement Requirement;
   1606     clang::Module::UnresolvedHeaderDirective MissingHeader;
   1607     if (!Module->isAvailable(getLangOpts(), getTarget(), Requirement,
   1608                              MissingHeader)) {
   1609       if (MissingHeader.FileNameLoc.isValid()) {
   1610         getDiagnostics().Report(MissingHeader.FileNameLoc,
   1611                                 diag::err_module_header_missing)
   1612           << MissingHeader.IsUmbrella << MissingHeader.FileName;
   1613       } else {
   1614         getDiagnostics().Report(ImportLoc, diag::err_module_unavailable)
   1615           << Module->getFullModuleName()
   1616           << Requirement.second << Requirement.first
   1617           << SourceRange(Path.front().second, Path.back().second);
   1618       }
   1619       LastModuleImportLoc = ImportLoc;
   1620       LastModuleImportResult = ModuleLoadResult();
   1621       return ModuleLoadResult();
   1622     }
   1623 
   1624     ModuleManager->makeModuleVisible(Module, Visibility, ImportLoc);
   1625   }
   1626 
   1627   // Check for any configuration macros that have changed.
   1628   clang::Module *TopModule = Module->getTopLevelModule();
   1629   for (unsigned I = 0, N = TopModule->ConfigMacros.size(); I != N; ++I) {
   1630     checkConfigMacro(getPreprocessor(), TopModule->ConfigMacros[I],
   1631                      Module, ImportLoc);
   1632   }
   1633 
   1634   LastModuleImportLoc = ImportLoc;
   1635   LastModuleImportResult = ModuleLoadResult(Module, false);
   1636   return LastModuleImportResult;
   1637 }
   1638 
   1639 void CompilerInstance::makeModuleVisible(Module *Mod,
   1640                                          Module::NameVisibilityKind Visibility,
   1641                                          SourceLocation ImportLoc) {
   1642   if (!ModuleManager)
   1643     createModuleManager();
   1644   if (!ModuleManager)
   1645     return;
   1646 
   1647   ModuleManager->makeModuleVisible(Mod, Visibility, ImportLoc);
   1648 }
   1649 
   1650 GlobalModuleIndex *CompilerInstance::loadGlobalModuleIndex(
   1651     SourceLocation TriggerLoc) {
   1652   if (getPreprocessor().getHeaderSearchInfo().getModuleCachePath().empty())
   1653     return nullptr;
   1654   if (!ModuleManager)
   1655     createModuleManager();
   1656   // Can't do anything if we don't have the module manager.
   1657   if (!ModuleManager)
   1658     return nullptr;
   1659   // Get an existing global index.  This loads it if not already
   1660   // loaded.
   1661   ModuleManager->loadGlobalIndex();
   1662   GlobalModuleIndex *GlobalIndex = ModuleManager->getGlobalIndex();
   1663   // If the global index doesn't exist, create it.
   1664   if (!GlobalIndex && shouldBuildGlobalModuleIndex() && hasFileManager() &&
   1665       hasPreprocessor()) {
   1666     llvm::sys::fs::create_directories(
   1667       getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
   1668     GlobalModuleIndex::writeIndex(
   1669         getFileManager(), getPCHContainerReader(),
   1670         getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
   1671     ModuleManager->resetForReload();
   1672     ModuleManager->loadGlobalIndex();
   1673     GlobalIndex = ModuleManager->getGlobalIndex();
   1674   }
   1675   // For finding modules needing to be imported for fixit messages,
   1676   // we need to make the global index cover all modules, so we do that here.
   1677   if (!HaveFullGlobalModuleIndex && GlobalIndex && !buildingModule()) {
   1678     ModuleMap &MMap = getPreprocessor().getHeaderSearchInfo().getModuleMap();
   1679     bool RecreateIndex = false;
   1680     for (ModuleMap::module_iterator I = MMap.module_begin(),
   1681         E = MMap.module_end(); I != E; ++I) {
   1682       Module *TheModule = I->second;
   1683       const FileEntry *Entry = TheModule->getASTFile();
   1684       if (!Entry) {
   1685         SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 2> Path;
   1686         Path.push_back(std::make_pair(
   1687             getPreprocessor().getIdentifierInfo(TheModule->Name), TriggerLoc));
   1688         std::reverse(Path.begin(), Path.end());
   1689         // Load a module as hidden.  This also adds it to the global index.
   1690         loadModule(TheModule->DefinitionLoc, Path, Module::Hidden, false);
   1691         RecreateIndex = true;
   1692       }
   1693     }
   1694     if (RecreateIndex) {
   1695       GlobalModuleIndex::writeIndex(
   1696           getFileManager(), getPCHContainerReader(),
   1697           getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
   1698       ModuleManager->resetForReload();
   1699       ModuleManager->loadGlobalIndex();
   1700       GlobalIndex = ModuleManager->getGlobalIndex();
   1701     }
   1702     HaveFullGlobalModuleIndex = true;
   1703   }
   1704   return GlobalIndex;
   1705 }
   1706 
   1707 // Check global module index for missing imports.
   1708 bool
   1709 CompilerInstance::lookupMissingImports(StringRef Name,
   1710                                        SourceLocation TriggerLoc) {
   1711   // Look for the symbol in non-imported modules, but only if an error
   1712   // actually occurred.
   1713   if (!buildingModule()) {
   1714     // Load global module index, or retrieve a previously loaded one.
   1715     GlobalModuleIndex *GlobalIndex = loadGlobalModuleIndex(
   1716       TriggerLoc);
   1717 
   1718     // Only if we have a global index.
   1719     if (GlobalIndex) {
   1720       GlobalModuleIndex::HitSet FoundModules;
   1721 
   1722       // Find the modules that reference the identifier.
   1723       // Note that this only finds top-level modules.
   1724       // We'll let diagnoseTypo find the actual declaration module.
   1725       if (GlobalIndex->lookupIdentifier(Name, FoundModules))
   1726         return true;
   1727     }
   1728   }
   1729 
   1730   return false;
   1731 }
   1732 void CompilerInstance::resetAndLeakSema() { BuryPointer(takeSema()); }
   1733