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