xref: /llvm-project/clang/lib/Frontend/CompilerInstance.cpp (revision ae032b6cf553bc9a274bcc2f30a68323a3296b98)
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/Lex/PreprocessorOptions.h"
33 #include "clang/Sema/CodeCompleteConsumer.h"
34 #include "clang/Sema/Sema.h"
35 #include "clang/Serialization/ASTReader.h"
36 #include "clang/Serialization/GlobalModuleIndex.h"
37 #include "llvm/ADT/Statistic.h"
38 #include "llvm/Support/CrashRecoveryContext.h"
39 #include "llvm/Support/Errc.h"
40 #include "llvm/Support/FileSystem.h"
41 #include "llvm/Support/Host.h"
42 #include "llvm/Support/LockFileManager.h"
43 #include "llvm/Support/MemoryBuffer.h"
44 #include "llvm/Support/Path.h"
45 #include "llvm/Support/Program.h"
46 #include "llvm/Support/Signals.h"
47 #include "llvm/Support/Timer.h"
48 #include "llvm/Support/raw_ostream.h"
49 #include <sys/stat.h>
50 #include <system_error>
51 #include <time.h>
52 #include <utility>
53 
54 using namespace clang;
55 
56 CompilerInstance::CompilerInstance(
57     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
58     bool BuildingModule)
59     : ModuleLoader(BuildingModule), Invocation(new CompilerInvocation()),
60       ModuleManager(nullptr),
61       ThePCHContainerOperations(std::move(PCHContainerOps)),
62       BuildGlobalModuleIndex(false), HaveFullGlobalModuleIndex(false),
63       ModuleBuildFailed(false) {}
64 
65 CompilerInstance::~CompilerInstance() {
66   assert(OutputFiles.empty() && "Still output files in flight?");
67 }
68 
69 void CompilerInstance::setInvocation(CompilerInvocation *Value) {
70   Invocation = Value;
71 }
72 
73 bool CompilerInstance::shouldBuildGlobalModuleIndex() const {
74   return (BuildGlobalModuleIndex ||
75           (ModuleManager && ModuleManager->isGlobalIndexUnavailable() &&
76            getFrontendOpts().GenerateGlobalModuleIndex)) &&
77          !ModuleBuildFailed;
78 }
79 
80 void CompilerInstance::setDiagnostics(DiagnosticsEngine *Value) {
81   Diagnostics = Value;
82 }
83 
84 void CompilerInstance::setTarget(TargetInfo *Value) { Target = Value; }
85 void CompilerInstance::setAuxTarget(TargetInfo *Value) { AuxTarget = Value; }
86 
87 void CompilerInstance::setFileManager(FileManager *Value) {
88   FileMgr = Value;
89   if (Value)
90     VirtualFileSystem = Value->getVirtualFileSystem();
91   else
92     VirtualFileSystem.reset();
93 }
94 
95 void CompilerInstance::setSourceManager(SourceManager *Value) {
96   SourceMgr = Value;
97 }
98 
99 void CompilerInstance::setPreprocessor(Preprocessor *Value) { PP = Value; }
100 
101 void CompilerInstance::setASTContext(ASTContext *Value) {
102   Context = Value;
103 
104   if (Context && Consumer)
105     getASTConsumer().Initialize(getASTContext());
106 }
107 
108 void CompilerInstance::setSema(Sema *S) {
109   TheSema.reset(S);
110 }
111 
112 void CompilerInstance::setASTConsumer(std::unique_ptr<ASTConsumer> Value) {
113   Consumer = std::move(Value);
114 
115   if (Context && Consumer)
116     getASTConsumer().Initialize(getASTContext());
117 }
118 
119 void CompilerInstance::setCodeCompletionConsumer(CodeCompleteConsumer *Value) {
120   CompletionConsumer.reset(Value);
121 }
122 
123 std::unique_ptr<Sema> CompilerInstance::takeSema() {
124   return std::move(TheSema);
125 }
126 
127 IntrusiveRefCntPtr<ASTReader> CompilerInstance::getModuleManager() const {
128   return ModuleManager;
129 }
130 void CompilerInstance::setModuleManager(IntrusiveRefCntPtr<ASTReader> Reader) {
131   ModuleManager = std::move(Reader);
132 }
133 
134 std::shared_ptr<ModuleDependencyCollector>
135 CompilerInstance::getModuleDepCollector() const {
136   return ModuleDepCollector;
137 }
138 
139 void CompilerInstance::setModuleDepCollector(
140     std::shared_ptr<ModuleDependencyCollector> Collector) {
141   ModuleDepCollector = std::move(Collector);
142 }
143 
144 // Diagnostics
145 static void SetUpDiagnosticLog(DiagnosticOptions *DiagOpts,
146                                const CodeGenOptions *CodeGenOpts,
147                                DiagnosticsEngine &Diags) {
148   std::error_code EC;
149   std::unique_ptr<raw_ostream> StreamOwner;
150   raw_ostream *OS = &llvm::errs();
151   if (DiagOpts->DiagnosticLogFile != "-") {
152     // Create the output stream.
153     auto FileOS = llvm::make_unique<llvm::raw_fd_ostream>(
154         DiagOpts->DiagnosticLogFile, EC,
155         llvm::sys::fs::F_Append | llvm::sys::fs::F_Text);
156     if (EC) {
157       Diags.Report(diag::warn_fe_cc_log_diagnostics_failure)
158           << DiagOpts->DiagnosticLogFile << EC.message();
159     } else {
160       FileOS->SetUnbuffered();
161       OS = FileOS.get();
162       StreamOwner = std::move(FileOS);
163     }
164   }
165 
166   // Chain in the diagnostic client which will log the diagnostics.
167   auto Logger = llvm::make_unique<LogDiagnosticPrinter>(*OS, DiagOpts,
168                                                         std::move(StreamOwner));
169   if (CodeGenOpts)
170     Logger->setDwarfDebugFlags(CodeGenOpts->DwarfDebugFlags);
171   assert(Diags.ownsClient());
172   Diags.setClient(
173       new ChainedDiagnosticConsumer(Diags.takeClient(), std::move(Logger)));
174 }
175 
176 static void SetupSerializedDiagnostics(DiagnosticOptions *DiagOpts,
177                                        DiagnosticsEngine &Diags,
178                                        StringRef OutputFile) {
179   auto SerializedConsumer =
180       clang::serialized_diags::create(OutputFile, DiagOpts);
181 
182   if (Diags.ownsClient()) {
183     Diags.setClient(new ChainedDiagnosticConsumer(
184         Diags.takeClient(), std::move(SerializedConsumer)));
185   } else {
186     Diags.setClient(new ChainedDiagnosticConsumer(
187         Diags.getClient(), std::move(SerializedConsumer)));
188   }
189 }
190 
191 void CompilerInstance::createDiagnostics(DiagnosticConsumer *Client,
192                                          bool ShouldOwnClient) {
193   Diagnostics = createDiagnostics(&getDiagnosticOpts(), Client,
194                                   ShouldOwnClient, &getCodeGenOpts());
195 }
196 
197 IntrusiveRefCntPtr<DiagnosticsEngine>
198 CompilerInstance::createDiagnostics(DiagnosticOptions *Opts,
199                                     DiagnosticConsumer *Client,
200                                     bool ShouldOwnClient,
201                                     const CodeGenOptions *CodeGenOpts) {
202   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
203   IntrusiveRefCntPtr<DiagnosticsEngine>
204       Diags(new DiagnosticsEngine(DiagID, Opts));
205 
206   // Create the diagnostic client for reporting errors or for
207   // implementing -verify.
208   if (Client) {
209     Diags->setClient(Client, ShouldOwnClient);
210   } else
211     Diags->setClient(new TextDiagnosticPrinter(llvm::errs(), Opts));
212 
213   // Chain in -verify checker, if requested.
214   if (Opts->VerifyDiagnostics)
215     Diags->setClient(new VerifyDiagnosticConsumer(*Diags));
216 
217   // Chain in -diagnostic-log-file dumper, if requested.
218   if (!Opts->DiagnosticLogFile.empty())
219     SetUpDiagnosticLog(Opts, CodeGenOpts, *Diags);
220 
221   if (!Opts->DiagnosticSerializationFile.empty())
222     SetupSerializedDiagnostics(Opts, *Diags,
223                                Opts->DiagnosticSerializationFile);
224 
225   // Configure our handling of diagnostics.
226   ProcessWarningOptions(*Diags, *Opts);
227 
228   return Diags;
229 }
230 
231 // File Manager
232 
233 void CompilerInstance::createFileManager() {
234   if (!hasVirtualFileSystem()) {
235     // TODO: choose the virtual file system based on the CompilerInvocation.
236     setVirtualFileSystem(vfs::getRealFileSystem());
237   }
238   FileMgr = new FileManager(getFileSystemOpts(), VirtualFileSystem);
239 }
240 
241 // Source Manager
242 
243 void CompilerInstance::createSourceManager(FileManager &FileMgr) {
244   SourceMgr = new SourceManager(getDiagnostics(), FileMgr);
245 }
246 
247 // Initialize the remapping of files to alternative contents, e.g.,
248 // those specified through other files.
249 static void InitializeFileRemapping(DiagnosticsEngine &Diags,
250                                     SourceManager &SourceMgr,
251                                     FileManager &FileMgr,
252                                     const PreprocessorOptions &InitOpts) {
253   // Remap files in the source manager (with buffers).
254   for (const auto &RB : InitOpts.RemappedFileBuffers) {
255     // Create the file entry for the file that we're mapping from.
256     const FileEntry *FromFile =
257         FileMgr.getVirtualFile(RB.first, RB.second->getBufferSize(), 0);
258     if (!FromFile) {
259       Diags.Report(diag::err_fe_remap_missing_from_file) << RB.first;
260       if (!InitOpts.RetainRemappedFileBuffers)
261         delete RB.second;
262       continue;
263     }
264 
265     // Override the contents of the "from" file with the contents of
266     // the "to" file.
267     SourceMgr.overrideFileContents(FromFile, RB.second,
268                                    InitOpts.RetainRemappedFileBuffers);
269   }
270 
271   // Remap files in the source manager (with other files).
272   for (const auto &RF : InitOpts.RemappedFiles) {
273     // Find the file that we're mapping to.
274     const FileEntry *ToFile = FileMgr.getFile(RF.second);
275     if (!ToFile) {
276       Diags.Report(diag::err_fe_remap_missing_to_file) << RF.first << RF.second;
277       continue;
278     }
279 
280     // Create the file entry for the file that we're mapping from.
281     const FileEntry *FromFile =
282         FileMgr.getVirtualFile(RF.first, ToFile->getSize(), 0);
283     if (!FromFile) {
284       Diags.Report(diag::err_fe_remap_missing_from_file) << RF.first;
285       continue;
286     }
287 
288     // Override the contents of the "from" file with the contents of
289     // the "to" file.
290     SourceMgr.overrideFileContents(FromFile, ToFile);
291   }
292 
293   SourceMgr.setOverridenFilesKeepOriginalName(
294       InitOpts.RemappedFilesKeepOriginalName);
295 }
296 
297 // Preprocessor
298 
299 void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
300   const PreprocessorOptions &PPOpts = getPreprocessorOpts();
301 
302   // Create a PTH manager if we are using some form of a token cache.
303   PTHManager *PTHMgr = nullptr;
304   if (!PPOpts.TokenCache.empty())
305     PTHMgr = PTHManager::Create(PPOpts.TokenCache, getDiagnostics());
306 
307   // Create the Preprocessor.
308   HeaderSearch *HeaderInfo = new HeaderSearch(&getHeaderSearchOpts(),
309                                               getSourceManager(),
310                                               getDiagnostics(),
311                                               getLangOpts(),
312                                               &getTarget());
313   PP = new Preprocessor(&getPreprocessorOpts(), getDiagnostics(), getLangOpts(),
314                         getSourceManager(), *HeaderInfo, *this, PTHMgr,
315                         /*OwnsHeaderSearch=*/true, TUKind);
316   PP->Initialize(getTarget(), getAuxTarget());
317 
318   // Note that this is different then passing PTHMgr to Preprocessor's ctor.
319   // That argument is used as the IdentifierInfoLookup argument to
320   // IdentifierTable's ctor.
321   if (PTHMgr) {
322     PTHMgr->setPreprocessor(&*PP);
323     PP->setPTHManager(PTHMgr);
324   }
325 
326   if (PPOpts.DetailedRecord)
327     PP->createPreprocessingRecord();
328 
329   // Apply remappings to the source manager.
330   InitializeFileRemapping(PP->getDiagnostics(), PP->getSourceManager(),
331                           PP->getFileManager(), PPOpts);
332 
333   // Predefine macros and configure the preprocessor.
334   InitializePreprocessor(*PP, PPOpts, getPCHContainerReader(),
335                          getFrontendOpts());
336 
337   // Initialize the header search object.  In CUDA compilations, we use the aux
338   // triple (the host triple) to initialize our header search, since we need to
339   // find the host headers in order to compile the CUDA code.
340   const llvm::Triple *HeaderSearchTriple = &PP->getTargetInfo().getTriple();
341   if (PP->getTargetInfo().getTriple().getOS() == llvm::Triple::CUDA &&
342       PP->getAuxTargetInfo())
343     HeaderSearchTriple = &PP->getAuxTargetInfo()->getTriple();
344 
345   ApplyHeaderSearchOptions(PP->getHeaderSearchInfo(), getHeaderSearchOpts(),
346                            PP->getLangOpts(), *HeaderSearchTriple);
347 
348   PP->setPreprocessedOutput(getPreprocessorOutputOpts().ShowCPP);
349 
350   if (PP->getLangOpts().Modules && PP->getLangOpts().ImplicitModules)
351     PP->getHeaderSearchInfo().setModuleCachePath(getSpecificModuleCachePath());
352 
353   // Handle generating dependencies, if requested.
354   const DependencyOutputOptions &DepOpts = getDependencyOutputOpts();
355   if (!DepOpts.OutputFile.empty())
356     TheDependencyFileGenerator.reset(
357         DependencyFileGenerator::CreateAndAttachToPreprocessor(*PP, DepOpts));
358   if (!DepOpts.DOTOutputFile.empty())
359     AttachDependencyGraphGen(*PP, DepOpts.DOTOutputFile,
360                              getHeaderSearchOpts().Sysroot);
361 
362   // If we don't have a collector, but we are collecting module dependencies,
363   // then we're the top level compiler instance and need to create one.
364   if (!ModuleDepCollector && !DepOpts.ModuleDependencyOutputDir.empty()) {
365     ModuleDepCollector = std::make_shared<ModuleDependencyCollector>(
366         DepOpts.ModuleDependencyOutputDir);
367   }
368 
369   if (ModuleDepCollector)
370     addDependencyCollector(ModuleDepCollector);
371 
372   for (auto &Listener : DependencyCollectors)
373     Listener->attachToPreprocessor(*PP);
374 
375   // Handle generating header include information, if requested.
376   if (DepOpts.ShowHeaderIncludes)
377     AttachHeaderIncludeGen(*PP, DepOpts);
378   if (!DepOpts.HeaderIncludeOutputFile.empty()) {
379     StringRef OutputPath = DepOpts.HeaderIncludeOutputFile;
380     if (OutputPath == "-")
381       OutputPath = "";
382     AttachHeaderIncludeGen(*PP, DepOpts,
383                            /*ShowAllHeaders=*/true, OutputPath,
384                            /*ShowDepth=*/false);
385   }
386 
387   if (DepOpts.PrintShowIncludes) {
388     AttachHeaderIncludeGen(*PP, DepOpts,
389                            /*ShowAllHeaders=*/true, /*OutputPath=*/"",
390                            /*ShowDepth=*/true, /*MSStyle=*/true);
391   }
392 }
393 
394 std::string CompilerInstance::getSpecificModuleCachePath() {
395   // Set up the module path, including the hash for the
396   // module-creation options.
397   SmallString<256> SpecificModuleCache(getHeaderSearchOpts().ModuleCachePath);
398   if (!SpecificModuleCache.empty() && !getHeaderSearchOpts().DisableModuleHash)
399     llvm::sys::path::append(SpecificModuleCache,
400                             getInvocation().getModuleHash());
401   return SpecificModuleCache.str();
402 }
403 
404 // ASTContext
405 
406 void CompilerInstance::createASTContext() {
407   Preprocessor &PP = getPreprocessor();
408   auto *Context = new ASTContext(getLangOpts(), PP.getSourceManager(),
409                                  PP.getIdentifierTable(), PP.getSelectorTable(),
410                                  PP.getBuiltinInfo());
411   Context->InitBuiltinTypes(getTarget(), getAuxTarget());
412   setASTContext(Context);
413 }
414 
415 // ExternalASTSource
416 
417 void CompilerInstance::createPCHExternalASTSource(
418     StringRef Path, bool DisablePCHValidation, bool AllowPCHWithCompilerErrors,
419     void *DeserializationListener, bool OwnDeserializationListener) {
420   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
421   ModuleManager = createPCHExternalASTSource(
422       Path, getHeaderSearchOpts().Sysroot, DisablePCHValidation,
423       AllowPCHWithCompilerErrors, getPreprocessor(), getASTContext(),
424       getPCHContainerReader(),
425       getFrontendOpts().ModuleFileExtensions,
426       DeserializationListener,
427       OwnDeserializationListener, Preamble,
428       getFrontendOpts().UseGlobalModuleIndex);
429 }
430 
431 IntrusiveRefCntPtr<ASTReader> CompilerInstance::createPCHExternalASTSource(
432     StringRef Path, StringRef Sysroot, bool DisablePCHValidation,
433     bool AllowPCHWithCompilerErrors, Preprocessor &PP, ASTContext &Context,
434     const PCHContainerReader &PCHContainerRdr,
435     ArrayRef<IntrusiveRefCntPtr<ModuleFileExtension>> Extensions,
436     void *DeserializationListener, bool OwnDeserializationListener,
437     bool Preamble, bool UseGlobalModuleIndex) {
438   HeaderSearchOptions &HSOpts = PP.getHeaderSearchInfo().getHeaderSearchOpts();
439 
440   IntrusiveRefCntPtr<ASTReader> Reader(new ASTReader(
441       PP, Context, PCHContainerRdr, Extensions,
442       Sysroot.empty() ? "" : Sysroot.data(), DisablePCHValidation,
443       AllowPCHWithCompilerErrors, /*AllowConfigurationMismatch*/ false,
444       HSOpts.ModulesValidateSystemHeaders, UseGlobalModuleIndex));
445 
446   // We need the external source to be set up before we read the AST, because
447   // eagerly-deserialized declarations may use it.
448   Context.setExternalSource(Reader.get());
449 
450   Reader->setDeserializationListener(
451       static_cast<ASTDeserializationListener *>(DeserializationListener),
452       /*TakeOwnership=*/OwnDeserializationListener);
453   switch (Reader->ReadAST(Path,
454                           Preamble ? serialization::MK_Preamble
455                                    : serialization::MK_PCH,
456                           SourceLocation(),
457                           ASTReader::ARR_None)) {
458   case ASTReader::Success:
459     // Set the predefines buffer as suggested by the PCH reader. Typically, the
460     // predefines buffer will be empty.
461     PP.setPredefines(Reader->getSuggestedPredefines());
462     return Reader;
463 
464   case ASTReader::Failure:
465     // Unrecoverable failure: don't even try to process the input file.
466     break;
467 
468   case ASTReader::Missing:
469   case ASTReader::OutOfDate:
470   case ASTReader::VersionMismatch:
471   case ASTReader::ConfigurationMismatch:
472   case ASTReader::HadErrors:
473     // No suitable PCH file could be found. Return an error.
474     break;
475   }
476 
477   Context.setExternalSource(nullptr);
478   return nullptr;
479 }
480 
481 // Code Completion
482 
483 static bool EnableCodeCompletion(Preprocessor &PP,
484                                  StringRef Filename,
485                                  unsigned Line,
486                                  unsigned Column) {
487   // Tell the source manager to chop off the given file at a specific
488   // line and column.
489   const FileEntry *Entry = PP.getFileManager().getFile(Filename);
490   if (!Entry) {
491     PP.getDiagnostics().Report(diag::err_fe_invalid_code_complete_file)
492       << Filename;
493     return true;
494   }
495 
496   // Truncate the named file at the given line/column.
497   PP.SetCodeCompletionPoint(Entry, Line, Column);
498   return false;
499 }
500 
501 void CompilerInstance::createCodeCompletionConsumer() {
502   const ParsedSourceLocation &Loc = getFrontendOpts().CodeCompletionAt;
503   if (!CompletionConsumer) {
504     setCodeCompletionConsumer(
505       createCodeCompletionConsumer(getPreprocessor(),
506                                    Loc.FileName, Loc.Line, Loc.Column,
507                                    getFrontendOpts().CodeCompleteOpts,
508                                    llvm::outs()));
509     if (!CompletionConsumer)
510       return;
511   } else if (EnableCodeCompletion(getPreprocessor(), Loc.FileName,
512                                   Loc.Line, Loc.Column)) {
513     setCodeCompletionConsumer(nullptr);
514     return;
515   }
516 
517   if (CompletionConsumer->isOutputBinary() &&
518       llvm::sys::ChangeStdoutToBinary()) {
519     getPreprocessor().getDiagnostics().Report(diag::err_fe_stdout_binary);
520     setCodeCompletionConsumer(nullptr);
521   }
522 }
523 
524 void CompilerInstance::createFrontendTimer() {
525   FrontendTimerGroup.reset(
526       new llvm::TimerGroup("frontend", "Clang front-end time report"));
527   FrontendTimer.reset(
528       new llvm::Timer("frontend", "Clang front-end timer",
529                       *FrontendTimerGroup));
530 }
531 
532 CodeCompleteConsumer *
533 CompilerInstance::createCodeCompletionConsumer(Preprocessor &PP,
534                                                StringRef Filename,
535                                                unsigned Line,
536                                                unsigned Column,
537                                                const CodeCompleteOptions &Opts,
538                                                raw_ostream &OS) {
539   if (EnableCodeCompletion(PP, Filename, Line, Column))
540     return nullptr;
541 
542   // Set up the creation routine for code-completion.
543   return new PrintingCodeCompleteConsumer(Opts, OS);
544 }
545 
546 void CompilerInstance::createSema(TranslationUnitKind TUKind,
547                                   CodeCompleteConsumer *CompletionConsumer) {
548   TheSema.reset(new Sema(getPreprocessor(), getASTContext(), getASTConsumer(),
549                          TUKind, CompletionConsumer));
550   // Attach the external sema source if there is any.
551   if (ExternalSemaSrc) {
552     TheSema->addExternalSource(ExternalSemaSrc.get());
553     ExternalSemaSrc->InitializeSema(*TheSema);
554   }
555 }
556 
557 // Output Files
558 
559 void CompilerInstance::addOutputFile(OutputFile &&OutFile) {
560   OutputFiles.push_back(std::move(OutFile));
561 }
562 
563 void CompilerInstance::clearOutputFiles(bool EraseFiles) {
564   for (OutputFile &OF : OutputFiles) {
565     if (!OF.TempFilename.empty()) {
566       if (EraseFiles) {
567         llvm::sys::fs::remove(OF.TempFilename);
568       } else {
569         SmallString<128> NewOutFile(OF.Filename);
570 
571         // If '-working-directory' was passed, the output filename should be
572         // relative to that.
573         FileMgr->FixupRelativePath(NewOutFile);
574         if (std::error_code ec =
575                 llvm::sys::fs::rename(OF.TempFilename, NewOutFile)) {
576           getDiagnostics().Report(diag::err_unable_to_rename_temp)
577             << OF.TempFilename << OF.Filename << ec.message();
578 
579           llvm::sys::fs::remove(OF.TempFilename);
580         }
581       }
582     } else if (!OF.Filename.empty() && EraseFiles)
583       llvm::sys::fs::remove(OF.Filename);
584   }
585   OutputFiles.clear();
586   NonSeekStream.reset();
587 }
588 
589 std::unique_ptr<raw_pwrite_stream>
590 CompilerInstance::createDefaultOutputFile(bool Binary, StringRef InFile,
591                                           StringRef Extension) {
592   return createOutputFile(getFrontendOpts().OutputFile, Binary,
593                           /*RemoveFileOnSignal=*/true, InFile, Extension,
594                           /*UseTemporary=*/true);
595 }
596 
597 std::unique_ptr<raw_pwrite_stream> CompilerInstance::createNullOutputFile() {
598   return llvm::make_unique<llvm::raw_null_ostream>();
599 }
600 
601 std::unique_ptr<raw_pwrite_stream>
602 CompilerInstance::createOutputFile(StringRef OutputPath, bool Binary,
603                                    bool RemoveFileOnSignal, StringRef InFile,
604                                    StringRef Extension, bool UseTemporary,
605                                    bool CreateMissingDirectories) {
606   std::string OutputPathName, TempPathName;
607   std::error_code EC;
608   std::unique_ptr<raw_pwrite_stream> OS = createOutputFile(
609       OutputPath, EC, Binary, RemoveFileOnSignal, InFile, Extension,
610       UseTemporary, CreateMissingDirectories, &OutputPathName, &TempPathName);
611   if (!OS) {
612     getDiagnostics().Report(diag::err_fe_unable_to_open_output) << OutputPath
613                                                                 << EC.message();
614     return nullptr;
615   }
616 
617   // Add the output file -- but don't try to remove "-", since this means we are
618   // using stdin.
619   addOutputFile(
620       OutputFile((OutputPathName != "-") ? OutputPathName : "", TempPathName));
621 
622   return OS;
623 }
624 
625 std::unique_ptr<llvm::raw_pwrite_stream> CompilerInstance::createOutputFile(
626     StringRef OutputPath, std::error_code &Error, bool Binary,
627     bool RemoveFileOnSignal, StringRef InFile, StringRef Extension,
628     bool UseTemporary, bool CreateMissingDirectories,
629     std::string *ResultPathName, std::string *TempPathName) {
630   assert((!CreateMissingDirectories || UseTemporary) &&
631          "CreateMissingDirectories is only allowed when using temporary files");
632 
633   std::string OutFile, TempFile;
634   if (!OutputPath.empty()) {
635     OutFile = OutputPath;
636   } else if (InFile == "-") {
637     OutFile = "-";
638   } else if (!Extension.empty()) {
639     SmallString<128> Path(InFile);
640     llvm::sys::path::replace_extension(Path, Extension);
641     OutFile = Path.str();
642   } else {
643     OutFile = "-";
644   }
645 
646   std::unique_ptr<llvm::raw_fd_ostream> OS;
647   std::string OSFile;
648 
649   if (UseTemporary) {
650     if (OutFile == "-")
651       UseTemporary = false;
652     else {
653       llvm::sys::fs::file_status Status;
654       llvm::sys::fs::status(OutputPath, Status);
655       if (llvm::sys::fs::exists(Status)) {
656         // Fail early if we can't write to the final destination.
657         if (!llvm::sys::fs::can_write(OutputPath)) {
658           Error = make_error_code(llvm::errc::operation_not_permitted);
659           return nullptr;
660         }
661 
662         // Don't use a temporary if the output is a special file. This handles
663         // things like '-o /dev/null'
664         if (!llvm::sys::fs::is_regular_file(Status))
665           UseTemporary = false;
666       }
667     }
668   }
669 
670   if (UseTemporary) {
671     // Create a temporary file.
672     SmallString<128> TempPath;
673     TempPath = OutFile;
674     TempPath += "-%%%%%%%%";
675     int fd;
676     std::error_code EC =
677         llvm::sys::fs::createUniqueFile(TempPath, fd, TempPath);
678 
679     if (CreateMissingDirectories &&
680         EC == llvm::errc::no_such_file_or_directory) {
681       StringRef Parent = llvm::sys::path::parent_path(OutputPath);
682       EC = llvm::sys::fs::create_directories(Parent);
683       if (!EC) {
684         EC = llvm::sys::fs::createUniqueFile(TempPath, fd, TempPath);
685       }
686     }
687 
688     if (!EC) {
689       OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
690       OSFile = TempFile = TempPath.str();
691     }
692     // If we failed to create the temporary, fallback to writing to the file
693     // directly. This handles the corner case where we cannot write to the
694     // directory, but can write to the file.
695   }
696 
697   if (!OS) {
698     OSFile = OutFile;
699     OS.reset(new llvm::raw_fd_ostream(
700         OSFile, Error,
701         (Binary ? llvm::sys::fs::F_None : llvm::sys::fs::F_Text)));
702     if (Error)
703       return nullptr;
704   }
705 
706   // Make sure the out stream file gets removed if we crash.
707   if (RemoveFileOnSignal)
708     llvm::sys::RemoveFileOnSignal(OSFile);
709 
710   if (ResultPathName)
711     *ResultPathName = OutFile;
712   if (TempPathName)
713     *TempPathName = TempFile;
714 
715   if (!Binary || OS->supportsSeeking())
716     return std::move(OS);
717 
718   auto B = llvm::make_unique<llvm::buffer_ostream>(*OS);
719   assert(!NonSeekStream);
720   NonSeekStream = std::move(OS);
721   return std::move(B);
722 }
723 
724 // Initialization Utilities
725 
726 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input){
727   return InitializeSourceManager(
728       Input, getDiagnostics(), getFileManager(), getSourceManager(),
729       hasPreprocessor() ? &getPreprocessor().getHeaderSearchInfo() : nullptr,
730       getDependencyOutputOpts(), getFrontendOpts());
731 }
732 
733 // static
734 bool CompilerInstance::InitializeSourceManager(
735     const FrontendInputFile &Input, DiagnosticsEngine &Diags,
736     FileManager &FileMgr, SourceManager &SourceMgr, HeaderSearch *HS,
737     DependencyOutputOptions &DepOpts, const FrontendOptions &Opts) {
738   SrcMgr::CharacteristicKind
739     Kind = Input.isSystem() ? SrcMgr::C_System : SrcMgr::C_User;
740 
741   if (Input.isBuffer()) {
742     SourceMgr.setMainFileID(SourceMgr.createFileID(
743         std::unique_ptr<llvm::MemoryBuffer>(Input.getBuffer()), Kind));
744     assert(SourceMgr.getMainFileID().isValid() &&
745            "Couldn't establish MainFileID!");
746     return true;
747   }
748 
749   StringRef InputFile = Input.getFile();
750 
751   // Figure out where to get and map in the main file.
752   if (InputFile != "-") {
753     const FileEntry *File;
754     if (Opts.FindPchSource.empty()) {
755       File = FileMgr.getFile(InputFile, /*OpenFile=*/true);
756     } else {
757       // When building a pch file in clang-cl mode, the .h file is built as if
758       // it was included by a cc file.  Since the driver doesn't know about
759       // all include search directories, the frontend must search the input
760       // file through HeaderSearch here, as if it had been included by the
761       // cc file at Opts.FindPchSource.
762       const FileEntry *FindFile = FileMgr.getFile(Opts.FindPchSource);
763       if (!FindFile) {
764         Diags.Report(diag::err_fe_error_reading) << Opts.FindPchSource;
765         return false;
766       }
767       const DirectoryLookup *UnusedCurDir;
768       SmallVector<std::pair<const FileEntry *, const DirectoryEntry *>, 16>
769           Includers;
770       Includers.push_back(std::make_pair(FindFile, FindFile->getDir()));
771       File = HS->LookupFile(InputFile, SourceLocation(), /*isAngled=*/false,
772                             /*FromDir=*/nullptr,
773                             /*CurDir=*/UnusedCurDir, Includers,
774                             /*SearchPath=*/nullptr,
775                             /*RelativePath=*/nullptr,
776                             /*RequestingModule=*/nullptr,
777                             /*SuggestedModule=*/nullptr, /*SkipCache=*/true);
778       // Also add the header to /showIncludes output.
779       if (File)
780         DepOpts.ShowIncludesPretendHeader = File->getName();
781     }
782     if (!File) {
783       Diags.Report(diag::err_fe_error_reading) << InputFile;
784       return false;
785     }
786 
787     // The natural SourceManager infrastructure can't currently handle named
788     // pipes, but we would at least like to accept them for the main
789     // file. Detect them here, read them with the volatile flag so FileMgr will
790     // pick up the correct size, and simply override their contents as we do for
791     // STDIN.
792     if (File->isNamedPipe()) {
793       auto MB = FileMgr.getBufferForFile(File, /*isVolatile=*/true);
794       if (MB) {
795         // Create a new virtual file that will have the correct size.
796         File = FileMgr.getVirtualFile(InputFile, (*MB)->getBufferSize(), 0);
797         SourceMgr.overrideFileContents(File, std::move(*MB));
798       } else {
799         Diags.Report(diag::err_cannot_open_file) << InputFile
800                                                  << MB.getError().message();
801         return false;
802       }
803     }
804 
805     SourceMgr.setMainFileID(
806         SourceMgr.createFileID(File, SourceLocation(), Kind));
807   } else {
808     llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> SBOrErr =
809         llvm::MemoryBuffer::getSTDIN();
810     if (std::error_code EC = SBOrErr.getError()) {
811       Diags.Report(diag::err_fe_error_reading_stdin) << EC.message();
812       return false;
813     }
814     std::unique_ptr<llvm::MemoryBuffer> SB = std::move(SBOrErr.get());
815 
816     const FileEntry *File = FileMgr.getVirtualFile(SB->getBufferIdentifier(),
817                                                    SB->getBufferSize(), 0);
818     SourceMgr.setMainFileID(
819         SourceMgr.createFileID(File, SourceLocation(), Kind));
820     SourceMgr.overrideFileContents(File, std::move(SB));
821   }
822 
823   assert(SourceMgr.getMainFileID().isValid() &&
824          "Couldn't establish MainFileID!");
825   return true;
826 }
827 
828 // High-Level Operations
829 
830 bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
831   assert(hasDiagnostics() && "Diagnostics engine is not initialized!");
832   assert(!getFrontendOpts().ShowHelp && "Client must handle '-help'!");
833   assert(!getFrontendOpts().ShowVersion && "Client must handle '-version'!");
834 
835   // FIXME: Take this as an argument, once all the APIs we used have moved to
836   // taking it as an input instead of hard-coding llvm::errs.
837   raw_ostream &OS = llvm::errs();
838 
839   // Create the target instance.
840   setTarget(TargetInfo::CreateTargetInfo(getDiagnostics(),
841                                          getInvocation().TargetOpts));
842   if (!hasTarget())
843     return false;
844 
845   // Create TargetInfo for the other side of CUDA compilation.
846   if (getLangOpts().CUDA && !getFrontendOpts().AuxTriple.empty()) {
847     auto TO = std::make_shared<TargetOptions>();
848     TO->Triple = getFrontendOpts().AuxTriple;
849     TO->HostTriple = getTarget().getTriple().str();
850     setAuxTarget(TargetInfo::CreateTargetInfo(getDiagnostics(), TO));
851   }
852 
853   // Inform the target of the language options.
854   //
855   // FIXME: We shouldn't need to do this, the target should be immutable once
856   // created. This complexity should be lifted elsewhere.
857   getTarget().adjust(getLangOpts());
858 
859   // Adjust target options based on codegen options.
860   getTarget().adjustTargetOptions(getCodeGenOpts(), getTargetOpts());
861 
862   // rewriter project will change target built-in bool type from its default.
863   if (getFrontendOpts().ProgramAction == frontend::RewriteObjC)
864     getTarget().noSignedCharForObjCBool();
865 
866   // Validate/process some options.
867   if (getHeaderSearchOpts().Verbose)
868     OS << "clang -cc1 version " CLANG_VERSION_STRING
869        << " based upon " << BACKEND_PACKAGE_STRING
870        << " default target " << llvm::sys::getDefaultTargetTriple() << "\n";
871 
872   if (getFrontendOpts().ShowTimers)
873     createFrontendTimer();
874 
875   if (getFrontendOpts().ShowStats || !getFrontendOpts().StatsFile.empty())
876     llvm::EnableStatistics(false);
877 
878   for (const FrontendInputFile &FIF : getFrontendOpts().Inputs) {
879     // Reset the ID tables if we are reusing the SourceManager and parsing
880     // regular files.
881     if (hasSourceManager() && !Act.isModelParsingAction())
882       getSourceManager().clearIDTables();
883 
884     if (Act.BeginSourceFile(*this, FIF)) {
885       Act.Execute();
886       Act.EndSourceFile();
887     }
888   }
889 
890   // Notify the diagnostic client that all files were processed.
891   getDiagnostics().getClient()->finish();
892 
893   if (getDiagnosticOpts().ShowCarets) {
894     // We can have multiple diagnostics sharing one diagnostic client.
895     // Get the total number of warnings/errors from the client.
896     unsigned NumWarnings = getDiagnostics().getClient()->getNumWarnings();
897     unsigned NumErrors = getDiagnostics().getClient()->getNumErrors();
898 
899     if (NumWarnings)
900       OS << NumWarnings << " warning" << (NumWarnings == 1 ? "" : "s");
901     if (NumWarnings && NumErrors)
902       OS << " and ";
903     if (NumErrors)
904       OS << NumErrors << " error" << (NumErrors == 1 ? "" : "s");
905     if (NumWarnings || NumErrors)
906       OS << " generated.\n";
907   }
908 
909   if (getFrontendOpts().ShowStats) {
910     if (hasFileManager()) {
911       getFileManager().PrintStats();
912       OS << '\n';
913     }
914     llvm::PrintStatistics(OS);
915   }
916   StringRef StatsFile = getFrontendOpts().StatsFile;
917   if (!StatsFile.empty()) {
918     std::error_code EC;
919     auto StatS = llvm::make_unique<llvm::raw_fd_ostream>(StatsFile, EC,
920                                                          llvm::sys::fs::F_Text);
921     if (EC) {
922       getDiagnostics().Report(diag::warn_fe_unable_to_open_stats_file)
923           << StatsFile << EC.message();
924     } else {
925       llvm::PrintStatisticsJSON(*StatS);
926     }
927   }
928 
929   return !getDiagnostics().getClient()->getNumErrors();
930 }
931 
932 /// \brief Determine the appropriate source input kind based on language
933 /// options.
934 static InputKind getSourceInputKindFromOptions(const LangOptions &LangOpts) {
935   if (LangOpts.OpenCL)
936     return IK_OpenCL;
937   if (LangOpts.CUDA)
938     return IK_CUDA;
939   if (LangOpts.ObjC1)
940     return LangOpts.CPlusPlus? IK_ObjCXX : IK_ObjC;
941   return LangOpts.CPlusPlus? IK_CXX : IK_C;
942 }
943 
944 /// \brief Compile a module file for the given module, using the options
945 /// provided by the importing compiler instance. Returns true if the module
946 /// was built without errors.
947 static bool compileModuleImpl(CompilerInstance &ImportingInstance,
948                               SourceLocation ImportLoc,
949                               Module *Module,
950                               StringRef ModuleFileName) {
951   ModuleMap &ModMap
952     = ImportingInstance.getPreprocessor().getHeaderSearchInfo().getModuleMap();
953 
954   // Construct a compiler invocation for creating this module.
955   IntrusiveRefCntPtr<CompilerInvocation> Invocation
956     (new CompilerInvocation(ImportingInstance.getInvocation()));
957 
958   PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
959 
960   // For any options that aren't intended to affect how a module is built,
961   // reset them to their default values.
962   Invocation->getLangOpts()->resetNonModularOptions();
963   PPOpts.resetNonModularOptions();
964 
965   // Remove any macro definitions that are explicitly ignored by the module.
966   // They aren't supposed to affect how the module is built anyway.
967   const HeaderSearchOptions &HSOpts = Invocation->getHeaderSearchOpts();
968   PPOpts.Macros.erase(
969       std::remove_if(PPOpts.Macros.begin(), PPOpts.Macros.end(),
970                      [&HSOpts](const std::pair<std::string, bool> &def) {
971         StringRef MacroDef = def.first;
972         return HSOpts.ModulesIgnoreMacros.count(
973                    llvm::CachedHashString(MacroDef.split('=').first)) > 0;
974       }),
975       PPOpts.Macros.end());
976 
977   // Note the name of the module we're building.
978   Invocation->getLangOpts()->CurrentModule = Module->getTopLevelModuleName();
979 
980   // Make sure that the failed-module structure has been allocated in
981   // the importing instance, and propagate the pointer to the newly-created
982   // instance.
983   PreprocessorOptions &ImportingPPOpts
984     = ImportingInstance.getInvocation().getPreprocessorOpts();
985   if (!ImportingPPOpts.FailedModules)
986     ImportingPPOpts.FailedModules = new PreprocessorOptions::FailedModulesSet;
987   PPOpts.FailedModules = ImportingPPOpts.FailedModules;
988 
989   // If there is a module map file, build the module using the module map.
990   // Set up the inputs/outputs so that we build the module from its umbrella
991   // header.
992   FrontendOptions &FrontendOpts = Invocation->getFrontendOpts();
993   FrontendOpts.OutputFile = ModuleFileName.str();
994   FrontendOpts.DisableFree = false;
995   FrontendOpts.GenerateGlobalModuleIndex = false;
996   FrontendOpts.BuildingImplicitModule = true;
997   FrontendOpts.Inputs.clear();
998   InputKind IK = getSourceInputKindFromOptions(*Invocation->getLangOpts());
999 
1000   // Don't free the remapped file buffers; they are owned by our caller.
1001   PPOpts.RetainRemappedFileBuffers = true;
1002 
1003   Invocation->getDiagnosticOpts().VerifyDiagnostics = 0;
1004   assert(ImportingInstance.getInvocation().getModuleHash() ==
1005          Invocation->getModuleHash() && "Module hash mismatch!");
1006 
1007   // Construct a compiler instance that will be used to actually create the
1008   // module.
1009   CompilerInstance Instance(ImportingInstance.getPCHContainerOperations(),
1010                             /*BuildingModule=*/true);
1011   Instance.setInvocation(&*Invocation);
1012 
1013   Instance.createDiagnostics(new ForwardingDiagnosticConsumer(
1014                                    ImportingInstance.getDiagnosticClient()),
1015                              /*ShouldOwnClient=*/true);
1016 
1017   Instance.setVirtualFileSystem(&ImportingInstance.getVirtualFileSystem());
1018 
1019   // Note that this module is part of the module build stack, so that we
1020   // can detect cycles in the module graph.
1021   Instance.setFileManager(&ImportingInstance.getFileManager());
1022   Instance.createSourceManager(Instance.getFileManager());
1023   SourceManager &SourceMgr = Instance.getSourceManager();
1024   SourceMgr.setModuleBuildStack(
1025     ImportingInstance.getSourceManager().getModuleBuildStack());
1026   SourceMgr.pushModuleBuildStack(Module->getTopLevelModuleName(),
1027     FullSourceLoc(ImportLoc, ImportingInstance.getSourceManager()));
1028 
1029   // If we're collecting module dependencies, we need to share a collector
1030   // between all of the module CompilerInstances. Other than that, we don't
1031   // want to produce any dependency output from the module build.
1032   Instance.setModuleDepCollector(ImportingInstance.getModuleDepCollector());
1033   Invocation->getDependencyOutputOpts() = DependencyOutputOptions();
1034 
1035   // Get or create the module map that we'll use to build this module.
1036   std::string InferredModuleMapContent;
1037   if (const FileEntry *ModuleMapFile =
1038           ModMap.getContainingModuleMapFile(Module)) {
1039     // Use the module map where this module resides.
1040     FrontendOpts.Inputs.emplace_back(ModuleMapFile->getName(), IK);
1041   } else {
1042     SmallString<128> FakeModuleMapFile(Module->Directory->getName());
1043     llvm::sys::path::append(FakeModuleMapFile, "__inferred_module.map");
1044     FrontendOpts.Inputs.emplace_back(FakeModuleMapFile, IK);
1045 
1046     llvm::raw_string_ostream OS(InferredModuleMapContent);
1047     Module->print(OS);
1048     OS.flush();
1049 
1050     std::unique_ptr<llvm::MemoryBuffer> ModuleMapBuffer =
1051         llvm::MemoryBuffer::getMemBuffer(InferredModuleMapContent);
1052     ModuleMapFile = Instance.getFileManager().getVirtualFile(
1053         FakeModuleMapFile, InferredModuleMapContent.size(), 0);
1054     SourceMgr.overrideFileContents(ModuleMapFile, std::move(ModuleMapBuffer));
1055   }
1056 
1057   // Construct a module-generating action. Passing through the module map is
1058   // safe because the FileManager is shared between the compiler instances.
1059   GenerateModuleFromModuleMapAction CreateModuleAction(
1060       ModMap.getModuleMapFileForUniquing(Module), Module->IsSystem);
1061 
1062   ImportingInstance.getDiagnostics().Report(ImportLoc,
1063                                             diag::remark_module_build)
1064     << Module->Name << ModuleFileName;
1065 
1066   // Execute the action to actually build the module in-place. Use a separate
1067   // thread so that we get a stack large enough.
1068   const unsigned ThreadStackSize = 8 << 20;
1069   llvm::CrashRecoveryContext CRC;
1070   CRC.RunSafelyOnThread([&]() { Instance.ExecuteAction(CreateModuleAction); },
1071                         ThreadStackSize);
1072 
1073   ImportingInstance.getDiagnostics().Report(ImportLoc,
1074                                             diag::remark_module_build_done)
1075     << Module->Name;
1076 
1077   // Delete the temporary module map file.
1078   // FIXME: Even though we're executing under crash protection, it would still
1079   // be nice to do this with RemoveFileOnSignal when we can. However, that
1080   // doesn't make sense for all clients, so clean this up manually.
1081   Instance.clearOutputFiles(/*EraseFiles=*/true);
1082 
1083   // We've rebuilt a module. If we're allowed to generate or update the global
1084   // module index, record that fact in the importing compiler instance.
1085   if (ImportingInstance.getFrontendOpts().GenerateGlobalModuleIndex) {
1086     ImportingInstance.setBuildGlobalModuleIndex(true);
1087   }
1088 
1089   return !Instance.getDiagnostics().hasErrorOccurred();
1090 }
1091 
1092 static bool compileAndLoadModule(CompilerInstance &ImportingInstance,
1093                                  SourceLocation ImportLoc,
1094                                  SourceLocation ModuleNameLoc, Module *Module,
1095                                  StringRef ModuleFileName) {
1096   DiagnosticsEngine &Diags = ImportingInstance.getDiagnostics();
1097 
1098   auto diagnoseBuildFailure = [&] {
1099     Diags.Report(ModuleNameLoc, diag::err_module_not_built)
1100         << Module->Name << SourceRange(ImportLoc, ModuleNameLoc);
1101   };
1102 
1103   // FIXME: have LockFileManager return an error_code so that we can
1104   // avoid the mkdir when the directory already exists.
1105   StringRef Dir = llvm::sys::path::parent_path(ModuleFileName);
1106   llvm::sys::fs::create_directories(Dir);
1107 
1108   while (1) {
1109     unsigned ModuleLoadCapabilities = ASTReader::ARR_Missing;
1110     llvm::LockFileManager Locked(ModuleFileName);
1111     switch (Locked) {
1112     case llvm::LockFileManager::LFS_Error:
1113       Diags.Report(ModuleNameLoc, diag::err_module_lock_failure)
1114           << Module->Name << Locked.getErrorMessage();
1115       return false;
1116 
1117     case llvm::LockFileManager::LFS_Owned:
1118       // We're responsible for building the module ourselves.
1119       if (!compileModuleImpl(ImportingInstance, ModuleNameLoc, Module,
1120                              ModuleFileName)) {
1121         diagnoseBuildFailure();
1122         return false;
1123       }
1124       break;
1125 
1126     case llvm::LockFileManager::LFS_Shared:
1127       // Someone else is responsible for building the module. Wait for them to
1128       // finish.
1129       switch (Locked.waitForUnlock()) {
1130       case llvm::LockFileManager::Res_Success:
1131         ModuleLoadCapabilities |= ASTReader::ARR_OutOfDate;
1132         break;
1133       case llvm::LockFileManager::Res_OwnerDied:
1134         continue; // try again to get the lock.
1135       case llvm::LockFileManager::Res_Timeout:
1136         Diags.Report(ModuleNameLoc, diag::err_module_lock_timeout)
1137             << Module->Name;
1138         // Clear the lock file so that future invokations can make progress.
1139         Locked.unsafeRemoveLockFile();
1140         return false;
1141       }
1142       break;
1143     }
1144 
1145     // Try to read the module file, now that we've compiled it.
1146     ASTReader::ASTReadResult ReadResult =
1147         ImportingInstance.getModuleManager()->ReadAST(
1148             ModuleFileName, serialization::MK_ImplicitModule, ImportLoc,
1149             ModuleLoadCapabilities);
1150 
1151     if (ReadResult == ASTReader::OutOfDate &&
1152         Locked == llvm::LockFileManager::LFS_Shared) {
1153       // The module may be out of date in the presence of file system races,
1154       // or if one of its imports depends on header search paths that are not
1155       // consistent with this ImportingInstance.  Try again...
1156       continue;
1157     } else if (ReadResult == ASTReader::Missing) {
1158       diagnoseBuildFailure();
1159     } else if (ReadResult != ASTReader::Success &&
1160                !Diags.hasErrorOccurred()) {
1161       // The ASTReader didn't diagnose the error, so conservatively report it.
1162       diagnoseBuildFailure();
1163     }
1164     return ReadResult == ASTReader::Success;
1165   }
1166 }
1167 
1168 /// \brief Diagnose differences between the current definition of the given
1169 /// configuration macro and the definition provided on the command line.
1170 static void checkConfigMacro(Preprocessor &PP, StringRef ConfigMacro,
1171                              Module *Mod, SourceLocation ImportLoc) {
1172   IdentifierInfo *Id = PP.getIdentifierInfo(ConfigMacro);
1173   SourceManager &SourceMgr = PP.getSourceManager();
1174 
1175   // If this identifier has never had a macro definition, then it could
1176   // not have changed.
1177   if (!Id->hadMacroDefinition())
1178     return;
1179   auto *LatestLocalMD = PP.getLocalMacroDirectiveHistory(Id);
1180 
1181   // Find the macro definition from the command line.
1182   MacroInfo *CmdLineDefinition = nullptr;
1183   for (auto *MD = LatestLocalMD; MD; MD = MD->getPrevious()) {
1184     // We only care about the predefines buffer.
1185     FileID FID = SourceMgr.getFileID(MD->getLocation());
1186     if (FID.isInvalid() || FID != PP.getPredefinesFileID())
1187       continue;
1188     if (auto *DMD = dyn_cast<DefMacroDirective>(MD))
1189       CmdLineDefinition = DMD->getMacroInfo();
1190     break;
1191   }
1192 
1193   auto *CurrentDefinition = PP.getMacroInfo(Id);
1194   if (CurrentDefinition == CmdLineDefinition) {
1195     // Macro matches. Nothing to do.
1196   } else if (!CurrentDefinition) {
1197     // This macro was defined on the command line, then #undef'd later.
1198     // Complain.
1199     PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
1200       << true << ConfigMacro << Mod->getFullModuleName();
1201     auto LatestDef = LatestLocalMD->getDefinition();
1202     assert(LatestDef.isUndefined() &&
1203            "predefined macro went away with no #undef?");
1204     PP.Diag(LatestDef.getUndefLocation(), diag::note_module_def_undef_here)
1205       << true;
1206     return;
1207   } else if (!CmdLineDefinition) {
1208     // There was no definition for this macro in the predefines buffer,
1209     // but there was a local definition. Complain.
1210     PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
1211       << false << ConfigMacro << Mod->getFullModuleName();
1212     PP.Diag(CurrentDefinition->getDefinitionLoc(),
1213             diag::note_module_def_undef_here)
1214       << false;
1215   } else if (!CurrentDefinition->isIdenticalTo(*CmdLineDefinition, PP,
1216                                                /*Syntactically=*/true)) {
1217     // The macro definitions differ.
1218     PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
1219       << false << ConfigMacro << Mod->getFullModuleName();
1220     PP.Diag(CurrentDefinition->getDefinitionLoc(),
1221             diag::note_module_def_undef_here)
1222       << false;
1223   }
1224 }
1225 
1226 /// \brief Write a new timestamp file with the given path.
1227 static void writeTimestampFile(StringRef TimestampFile) {
1228   std::error_code EC;
1229   llvm::raw_fd_ostream Out(TimestampFile.str(), EC, llvm::sys::fs::F_None);
1230 }
1231 
1232 /// \brief Prune the module cache of modules that haven't been accessed in
1233 /// a long time.
1234 static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
1235   struct stat StatBuf;
1236   llvm::SmallString<128> TimestampFile;
1237   TimestampFile = HSOpts.ModuleCachePath;
1238   assert(!TimestampFile.empty());
1239   llvm::sys::path::append(TimestampFile, "modules.timestamp");
1240 
1241   // Try to stat() the timestamp file.
1242   if (::stat(TimestampFile.c_str(), &StatBuf)) {
1243     // If the timestamp file wasn't there, create one now.
1244     if (errno == ENOENT) {
1245       writeTimestampFile(TimestampFile);
1246     }
1247     return;
1248   }
1249 
1250   // Check whether the time stamp is older than our pruning interval.
1251   // If not, do nothing.
1252   time_t TimeStampModTime = StatBuf.st_mtime;
1253   time_t CurrentTime = time(nullptr);
1254   if (CurrentTime - TimeStampModTime <= time_t(HSOpts.ModuleCachePruneInterval))
1255     return;
1256 
1257   // Write a new timestamp file so that nobody else attempts to prune.
1258   // There is a benign race condition here, if two Clang instances happen to
1259   // notice at the same time that the timestamp is out-of-date.
1260   writeTimestampFile(TimestampFile);
1261 
1262   // Walk the entire module cache, looking for unused module files and module
1263   // indices.
1264   std::error_code EC;
1265   SmallString<128> ModuleCachePathNative;
1266   llvm::sys::path::native(HSOpts.ModuleCachePath, ModuleCachePathNative);
1267   for (llvm::sys::fs::directory_iterator Dir(ModuleCachePathNative, EC), DirEnd;
1268        Dir != DirEnd && !EC; Dir.increment(EC)) {
1269     // If we don't have a directory, there's nothing to look into.
1270     if (!llvm::sys::fs::is_directory(Dir->path()))
1271       continue;
1272 
1273     // Walk all of the files within this directory.
1274     for (llvm::sys::fs::directory_iterator File(Dir->path(), EC), FileEnd;
1275          File != FileEnd && !EC; File.increment(EC)) {
1276       // We only care about module and global module index files.
1277       StringRef Extension = llvm::sys::path::extension(File->path());
1278       if (Extension != ".pcm" && Extension != ".timestamp" &&
1279           llvm::sys::path::filename(File->path()) != "modules.idx")
1280         continue;
1281 
1282       // Look at this file. If we can't stat it, there's nothing interesting
1283       // there.
1284       if (::stat(File->path().c_str(), &StatBuf))
1285         continue;
1286 
1287       // If the file has been used recently enough, leave it there.
1288       time_t FileAccessTime = StatBuf.st_atime;
1289       if (CurrentTime - FileAccessTime <=
1290               time_t(HSOpts.ModuleCachePruneAfter)) {
1291         continue;
1292       }
1293 
1294       // Remove the file.
1295       llvm::sys::fs::remove(File->path());
1296 
1297       // Remove the timestamp file.
1298       std::string TimpestampFilename = File->path() + ".timestamp";
1299       llvm::sys::fs::remove(TimpestampFilename);
1300     }
1301 
1302     // If we removed all of the files in the directory, remove the directory
1303     // itself.
1304     if (llvm::sys::fs::directory_iterator(Dir->path(), EC) ==
1305             llvm::sys::fs::directory_iterator() && !EC)
1306       llvm::sys::fs::remove(Dir->path());
1307   }
1308 }
1309 
1310 void CompilerInstance::createModuleManager() {
1311   if (!ModuleManager) {
1312     if (!hasASTContext())
1313       createASTContext();
1314 
1315     // If we're implicitly building modules but not currently recursively
1316     // building a module, check whether we need to prune the module cache.
1317     if (getSourceManager().getModuleBuildStack().empty() &&
1318         !getPreprocessor().getHeaderSearchInfo().getModuleCachePath().empty() &&
1319         getHeaderSearchOpts().ModuleCachePruneInterval > 0 &&
1320         getHeaderSearchOpts().ModuleCachePruneAfter > 0) {
1321       pruneModuleCache(getHeaderSearchOpts());
1322     }
1323 
1324     HeaderSearchOptions &HSOpts = getHeaderSearchOpts();
1325     std::string Sysroot = HSOpts.Sysroot;
1326     const PreprocessorOptions &PPOpts = getPreprocessorOpts();
1327     std::unique_ptr<llvm::Timer> ReadTimer;
1328     if (FrontendTimerGroup)
1329       ReadTimer = llvm::make_unique<llvm::Timer>("reading_modules",
1330                                                  "Reading modules",
1331                                                  *FrontendTimerGroup);
1332     ModuleManager = new ASTReader(
1333         getPreprocessor(), getASTContext(), getPCHContainerReader(),
1334         getFrontendOpts().ModuleFileExtensions,
1335         Sysroot.empty() ? "" : Sysroot.c_str(), PPOpts.DisablePCHValidation,
1336         /*AllowASTWithCompilerErrors=*/false,
1337         /*AllowConfigurationMismatch=*/false,
1338         HSOpts.ModulesValidateSystemHeaders,
1339         getFrontendOpts().UseGlobalModuleIndex,
1340         std::move(ReadTimer));
1341     if (hasASTConsumer()) {
1342       ModuleManager->setDeserializationListener(
1343         getASTConsumer().GetASTDeserializationListener());
1344       getASTContext().setASTMutationListener(
1345         getASTConsumer().GetASTMutationListener());
1346     }
1347     getASTContext().setExternalSource(ModuleManager);
1348     if (hasSema())
1349       ModuleManager->InitializeSema(getSema());
1350     if (hasASTConsumer())
1351       ModuleManager->StartTranslationUnit(&getASTConsumer());
1352 
1353     if (TheDependencyFileGenerator)
1354       TheDependencyFileGenerator->AttachToASTReader(*ModuleManager);
1355     for (auto &Listener : DependencyCollectors)
1356       Listener->attachToASTReader(*ModuleManager);
1357   }
1358 }
1359 
1360 bool CompilerInstance::loadModuleFile(StringRef FileName) {
1361   llvm::Timer Timer;
1362   if (FrontendTimerGroup)
1363     Timer.init("preloading." + FileName.str(), "Preloading " + FileName.str(),
1364                *FrontendTimerGroup);
1365   llvm::TimeRegion TimeLoading(FrontendTimerGroup ? &Timer : nullptr);
1366 
1367   // Helper to recursively read the module names for all modules we're adding.
1368   // We mark these as known and redirect any attempt to load that module to
1369   // the files we were handed.
1370   struct ReadModuleNames : ASTReaderListener {
1371     CompilerInstance &CI;
1372     llvm::SmallVector<IdentifierInfo*, 8> LoadedModules;
1373 
1374     ReadModuleNames(CompilerInstance &CI) : CI(CI) {}
1375 
1376     void ReadModuleName(StringRef ModuleName) override {
1377       LoadedModules.push_back(
1378           CI.getPreprocessor().getIdentifierInfo(ModuleName));
1379     }
1380 
1381     void registerAll() {
1382       for (auto *II : LoadedModules) {
1383         CI.KnownModules[II] = CI.getPreprocessor()
1384                                   .getHeaderSearchInfo()
1385                                   .getModuleMap()
1386                                   .findModule(II->getName());
1387       }
1388       LoadedModules.clear();
1389     }
1390 
1391     void markAllUnavailable() {
1392       for (auto *II : LoadedModules) {
1393         if (Module *M = CI.getPreprocessor()
1394                             .getHeaderSearchInfo()
1395                             .getModuleMap()
1396                             .findModule(II->getName()))
1397           M->HasIncompatibleModuleFile = true;
1398       }
1399       LoadedModules.clear();
1400     }
1401   };
1402 
1403   // If we don't already have an ASTReader, create one now.
1404   if (!ModuleManager)
1405     createModuleManager();
1406 
1407   auto Listener = llvm::make_unique<ReadModuleNames>(*this);
1408   auto &ListenerRef = *Listener;
1409   ASTReader::ListenerScope ReadModuleNamesListener(*ModuleManager,
1410                                                    std::move(Listener));
1411 
1412   // Try to load the module file.
1413   switch (ModuleManager->ReadAST(FileName, serialization::MK_ExplicitModule,
1414                                  SourceLocation(),
1415                                  ASTReader::ARR_ConfigurationMismatch)) {
1416   case ASTReader::Success:
1417     // We successfully loaded the module file; remember the set of provided
1418     // modules so that we don't try to load implicit modules for them.
1419     ListenerRef.registerAll();
1420     return true;
1421 
1422   case ASTReader::ConfigurationMismatch:
1423     // Ignore unusable module files.
1424     getDiagnostics().Report(SourceLocation(), diag::warn_module_config_mismatch)
1425         << FileName;
1426     // All modules provided by any files we tried and failed to load are now
1427     // unavailable; includes of those modules should now be handled textually.
1428     ListenerRef.markAllUnavailable();
1429     return true;
1430 
1431   default:
1432     return false;
1433   }
1434 }
1435 
1436 ModuleLoadResult
1437 CompilerInstance::loadModule(SourceLocation ImportLoc,
1438                              ModuleIdPath Path,
1439                              Module::NameVisibilityKind Visibility,
1440                              bool IsInclusionDirective) {
1441   // Determine what file we're searching from.
1442   StringRef ModuleName = Path[0].first->getName();
1443   SourceLocation ModuleNameLoc = Path[0].second;
1444 
1445   // If we've already handled this import, just return the cached result.
1446   // This one-element cache is important to eliminate redundant diagnostics
1447   // when both the preprocessor and parser see the same import declaration.
1448   if (ImportLoc.isValid() && LastModuleImportLoc == ImportLoc) {
1449     // Make the named module visible.
1450     if (LastModuleImportResult && ModuleName != getLangOpts().CurrentModule)
1451       ModuleManager->makeModuleVisible(LastModuleImportResult, Visibility,
1452                                        ImportLoc);
1453     return LastModuleImportResult;
1454   }
1455 
1456   clang::Module *Module = nullptr;
1457 
1458   // If we don't already have information on this module, load the module now.
1459   llvm::DenseMap<const IdentifierInfo *, clang::Module *>::iterator Known
1460     = KnownModules.find(Path[0].first);
1461   if (Known != KnownModules.end()) {
1462     // Retrieve the cached top-level module.
1463     Module = Known->second;
1464   } else if (ModuleName == getLangOpts().CurrentModule) {
1465     // This is the module we're building.
1466     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
1467     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1468   } else {
1469     // Search for a module with the given name.
1470     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
1471     HeaderSearchOptions &HSOpts =
1472         PP->getHeaderSearchInfo().getHeaderSearchOpts();
1473 
1474     std::string ModuleFileName;
1475     bool LoadFromPrebuiltModulePath = false;
1476     // We try to load the module from the prebuilt module paths. If not
1477     // successful, we then try to find it in the module cache.
1478     if (!HSOpts.PrebuiltModulePaths.empty()) {
1479       // Load the module from the prebuilt module path.
1480       ModuleFileName = PP->getHeaderSearchInfo().getModuleFileName(
1481           ModuleName, "", /*UsePrebuiltPath*/ true);
1482       if (!ModuleFileName.empty())
1483         LoadFromPrebuiltModulePath = true;
1484     }
1485     if (!LoadFromPrebuiltModulePath && Module) {
1486       // Load the module from the module cache.
1487       ModuleFileName = PP->getHeaderSearchInfo().getModuleFileName(Module);
1488     } else if (!LoadFromPrebuiltModulePath) {
1489       // We can't find a module, error out here.
1490       getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_found)
1491       << ModuleName
1492       << SourceRange(ImportLoc, ModuleNameLoc);
1493       ModuleBuildFailed = true;
1494       return ModuleLoadResult();
1495     }
1496 
1497     if (ModuleFileName.empty()) {
1498       if (Module && Module->HasIncompatibleModuleFile) {
1499         // We tried and failed to load a module file for this module. Fall
1500         // back to textual inclusion for its headers.
1501         return ModuleLoadResult(nullptr, /*missingExpected*/true);
1502       }
1503 
1504       getDiagnostics().Report(ModuleNameLoc, diag::err_module_build_disabled)
1505           << ModuleName;
1506       ModuleBuildFailed = true;
1507       return ModuleLoadResult();
1508     }
1509 
1510     // If we don't already have an ASTReader, create one now.
1511     if (!ModuleManager)
1512       createModuleManager();
1513 
1514     llvm::Timer Timer;
1515     if (FrontendTimerGroup)
1516       Timer.init("loading." + ModuleFileName, "Loading " + ModuleFileName,
1517                  *FrontendTimerGroup);
1518     llvm::TimeRegion TimeLoading(FrontendTimerGroup ? &Timer : nullptr);
1519 
1520     // Try to load the module file. If we are trying to load from the prebuilt
1521     // module path, we don't have the module map files and don't know how to
1522     // rebuild modules.
1523     unsigned ARRFlags = LoadFromPrebuiltModulePath ?
1524                         ASTReader::ARR_ConfigurationMismatch :
1525                         ASTReader::ARR_OutOfDate | ASTReader::ARR_Missing;
1526     switch (ModuleManager->ReadAST(ModuleFileName,
1527                                    LoadFromPrebuiltModulePath ?
1528                                    serialization::MK_PrebuiltModule :
1529                                    serialization::MK_ImplicitModule,
1530                                    ImportLoc,
1531                                    ARRFlags)) {
1532     case ASTReader::Success: {
1533       if (LoadFromPrebuiltModulePath && !Module) {
1534         Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
1535         if (!Module || !Module->getASTFile() ||
1536             FileMgr->getFile(ModuleFileName) != Module->getASTFile()) {
1537           // Error out if Module does not refer to the file in the prebuilt
1538           // module path.
1539           getDiagnostics().Report(ModuleNameLoc, diag::err_module_prebuilt)
1540               << ModuleName;
1541           ModuleBuildFailed = true;
1542           KnownModules[Path[0].first] = nullptr;
1543           return ModuleLoadResult();
1544         }
1545       }
1546       break;
1547     }
1548 
1549     case ASTReader::OutOfDate:
1550     case ASTReader::Missing: {
1551       if (LoadFromPrebuiltModulePath) {
1552         // We can't rebuild the module without a module map. Since ReadAST
1553         // already produces diagnostics for these two cases, we simply
1554         // error out here.
1555         ModuleBuildFailed = true;
1556         KnownModules[Path[0].first] = nullptr;
1557         return ModuleLoadResult();
1558       }
1559 
1560       // The module file is missing or out-of-date. Build it.
1561       assert(Module && "missing module file");
1562       // Check whether there is a cycle in the module graph.
1563       ModuleBuildStack ModPath = getSourceManager().getModuleBuildStack();
1564       ModuleBuildStack::iterator Pos = ModPath.begin(), PosEnd = ModPath.end();
1565       for (; Pos != PosEnd; ++Pos) {
1566         if (Pos->first == ModuleName)
1567           break;
1568       }
1569 
1570       if (Pos != PosEnd) {
1571         SmallString<256> CyclePath;
1572         for (; Pos != PosEnd; ++Pos) {
1573           CyclePath += Pos->first;
1574           CyclePath += " -> ";
1575         }
1576         CyclePath += ModuleName;
1577 
1578         getDiagnostics().Report(ModuleNameLoc, diag::err_module_cycle)
1579           << ModuleName << CyclePath;
1580         return ModuleLoadResult();
1581       }
1582 
1583       // Check whether we have already attempted to build this module (but
1584       // failed).
1585       if (getPreprocessorOpts().FailedModules &&
1586           getPreprocessorOpts().FailedModules->hasAlreadyFailed(ModuleName)) {
1587         getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_built)
1588           << ModuleName
1589           << SourceRange(ImportLoc, ModuleNameLoc);
1590         ModuleBuildFailed = true;
1591         return ModuleLoadResult();
1592       }
1593 
1594       // Try to compile and then load the module.
1595       if (!compileAndLoadModule(*this, ImportLoc, ModuleNameLoc, Module,
1596                                 ModuleFileName)) {
1597         assert(getDiagnostics().hasErrorOccurred() &&
1598                "undiagnosed error in compileAndLoadModule");
1599         if (getPreprocessorOpts().FailedModules)
1600           getPreprocessorOpts().FailedModules->addFailed(ModuleName);
1601         KnownModules[Path[0].first] = nullptr;
1602         ModuleBuildFailed = true;
1603         return ModuleLoadResult();
1604       }
1605 
1606       // Okay, we've rebuilt and now loaded the module.
1607       break;
1608     }
1609 
1610     case ASTReader::ConfigurationMismatch:
1611       if (LoadFromPrebuiltModulePath)
1612         getDiagnostics().Report(SourceLocation(),
1613                                 diag::warn_module_config_mismatch)
1614             << ModuleFileName;
1615       // Fall through to error out.
1616     case ASTReader::VersionMismatch:
1617     case ASTReader::HadErrors:
1618       ModuleLoader::HadFatalFailure = true;
1619       // FIXME: The ASTReader will already have complained, but can we shoehorn
1620       // that diagnostic information into a more useful form?
1621       KnownModules[Path[0].first] = nullptr;
1622       return ModuleLoadResult();
1623 
1624     case ASTReader::Failure:
1625       ModuleLoader::HadFatalFailure = true;
1626       // Already complained, but note now that we failed.
1627       KnownModules[Path[0].first] = nullptr;
1628       ModuleBuildFailed = true;
1629       return ModuleLoadResult();
1630     }
1631 
1632     // Cache the result of this top-level module lookup for later.
1633     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1634   }
1635 
1636   // If we never found the module, fail.
1637   if (!Module)
1638     return ModuleLoadResult();
1639 
1640   // Verify that the rest of the module path actually corresponds to
1641   // a submodule.
1642   if (Path.size() > 1) {
1643     for (unsigned I = 1, N = Path.size(); I != N; ++I) {
1644       StringRef Name = Path[I].first->getName();
1645       clang::Module *Sub = Module->findSubmodule(Name);
1646 
1647       if (!Sub) {
1648         // Attempt to perform typo correction to find a module name that works.
1649         SmallVector<StringRef, 2> Best;
1650         unsigned BestEditDistance = (std::numeric_limits<unsigned>::max)();
1651 
1652         for (clang::Module::submodule_iterator J = Module->submodule_begin(),
1653                                             JEnd = Module->submodule_end();
1654              J != JEnd; ++J) {
1655           unsigned ED = Name.edit_distance((*J)->Name,
1656                                            /*AllowReplacements=*/true,
1657                                            BestEditDistance);
1658           if (ED <= BestEditDistance) {
1659             if (ED < BestEditDistance) {
1660               Best.clear();
1661               BestEditDistance = ED;
1662             }
1663 
1664             Best.push_back((*J)->Name);
1665           }
1666         }
1667 
1668         // If there was a clear winner, user it.
1669         if (Best.size() == 1) {
1670           getDiagnostics().Report(Path[I].second,
1671                                   diag::err_no_submodule_suggest)
1672             << Path[I].first << Module->getFullModuleName() << Best[0]
1673             << SourceRange(Path[0].second, Path[I-1].second)
1674             << FixItHint::CreateReplacement(SourceRange(Path[I].second),
1675                                             Best[0]);
1676 
1677           Sub = Module->findSubmodule(Best[0]);
1678         }
1679       }
1680 
1681       if (!Sub) {
1682         // No submodule by this name. Complain, and don't look for further
1683         // submodules.
1684         getDiagnostics().Report(Path[I].second, diag::err_no_submodule)
1685           << Path[I].first << Module->getFullModuleName()
1686           << SourceRange(Path[0].second, Path[I-1].second);
1687         break;
1688       }
1689 
1690       Module = Sub;
1691     }
1692   }
1693 
1694   // Make the named module visible, if it's not already part of the module
1695   // we are parsing.
1696   if (ModuleName != getLangOpts().CurrentModule) {
1697     if (!Module->IsFromModuleFile) {
1698       // We have an umbrella header or directory that doesn't actually include
1699       // all of the headers within the directory it covers. Complain about
1700       // this missing submodule and recover by forgetting that we ever saw
1701       // this submodule.
1702       // FIXME: Should we detect this at module load time? It seems fairly
1703       // expensive (and rare).
1704       getDiagnostics().Report(ImportLoc, diag::warn_missing_submodule)
1705         << Module->getFullModuleName()
1706         << SourceRange(Path.front().second, Path.back().second);
1707 
1708       return ModuleLoadResult(nullptr, true);
1709     }
1710 
1711     // Check whether this module is available.
1712     clang::Module::Requirement Requirement;
1713     clang::Module::UnresolvedHeaderDirective MissingHeader;
1714     if (!Module->isAvailable(getLangOpts(), getTarget(), Requirement,
1715                              MissingHeader)) {
1716       if (MissingHeader.FileNameLoc.isValid()) {
1717         getDiagnostics().Report(MissingHeader.FileNameLoc,
1718                                 diag::err_module_header_missing)
1719           << MissingHeader.IsUmbrella << MissingHeader.FileName;
1720       } else {
1721         getDiagnostics().Report(ImportLoc, diag::err_module_unavailable)
1722           << Module->getFullModuleName()
1723           << Requirement.second << Requirement.first
1724           << SourceRange(Path.front().second, Path.back().second);
1725       }
1726       LastModuleImportLoc = ImportLoc;
1727       LastModuleImportResult = ModuleLoadResult();
1728       return ModuleLoadResult();
1729     }
1730 
1731     ModuleManager->makeModuleVisible(Module, Visibility, ImportLoc);
1732   }
1733 
1734   // Check for any configuration macros that have changed.
1735   clang::Module *TopModule = Module->getTopLevelModule();
1736   for (unsigned I = 0, N = TopModule->ConfigMacros.size(); I != N; ++I) {
1737     checkConfigMacro(getPreprocessor(), TopModule->ConfigMacros[I],
1738                      Module, ImportLoc);
1739   }
1740 
1741   LastModuleImportLoc = ImportLoc;
1742   LastModuleImportResult = ModuleLoadResult(Module, false);
1743   return LastModuleImportResult;
1744 }
1745 
1746 void CompilerInstance::makeModuleVisible(Module *Mod,
1747                                          Module::NameVisibilityKind Visibility,
1748                                          SourceLocation ImportLoc) {
1749   if (!ModuleManager)
1750     createModuleManager();
1751   if (!ModuleManager)
1752     return;
1753 
1754   ModuleManager->makeModuleVisible(Mod, Visibility, ImportLoc);
1755 }
1756 
1757 GlobalModuleIndex *CompilerInstance::loadGlobalModuleIndex(
1758     SourceLocation TriggerLoc) {
1759   if (getPreprocessor().getHeaderSearchInfo().getModuleCachePath().empty())
1760     return nullptr;
1761   if (!ModuleManager)
1762     createModuleManager();
1763   // Can't do anything if we don't have the module manager.
1764   if (!ModuleManager)
1765     return nullptr;
1766   // Get an existing global index.  This loads it if not already
1767   // loaded.
1768   ModuleManager->loadGlobalIndex();
1769   GlobalModuleIndex *GlobalIndex = ModuleManager->getGlobalIndex();
1770   // If the global index doesn't exist, create it.
1771   if (!GlobalIndex && shouldBuildGlobalModuleIndex() && hasFileManager() &&
1772       hasPreprocessor()) {
1773     llvm::sys::fs::create_directories(
1774       getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
1775     GlobalModuleIndex::writeIndex(
1776         getFileManager(), getPCHContainerReader(),
1777         getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
1778     ModuleManager->resetForReload();
1779     ModuleManager->loadGlobalIndex();
1780     GlobalIndex = ModuleManager->getGlobalIndex();
1781   }
1782   // For finding modules needing to be imported for fixit messages,
1783   // we need to make the global index cover all modules, so we do that here.
1784   if (!HaveFullGlobalModuleIndex && GlobalIndex && !buildingModule()) {
1785     ModuleMap &MMap = getPreprocessor().getHeaderSearchInfo().getModuleMap();
1786     bool RecreateIndex = false;
1787     for (ModuleMap::module_iterator I = MMap.module_begin(),
1788         E = MMap.module_end(); I != E; ++I) {
1789       Module *TheModule = I->second;
1790       const FileEntry *Entry = TheModule->getASTFile();
1791       if (!Entry) {
1792         SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 2> Path;
1793         Path.push_back(std::make_pair(
1794             getPreprocessor().getIdentifierInfo(TheModule->Name), TriggerLoc));
1795         std::reverse(Path.begin(), Path.end());
1796         // Load a module as hidden.  This also adds it to the global index.
1797         loadModule(TheModule->DefinitionLoc, Path, Module::Hidden, false);
1798         RecreateIndex = true;
1799       }
1800     }
1801     if (RecreateIndex) {
1802       GlobalModuleIndex::writeIndex(
1803           getFileManager(), getPCHContainerReader(),
1804           getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
1805       ModuleManager->resetForReload();
1806       ModuleManager->loadGlobalIndex();
1807       GlobalIndex = ModuleManager->getGlobalIndex();
1808     }
1809     HaveFullGlobalModuleIndex = true;
1810   }
1811   return GlobalIndex;
1812 }
1813 
1814 // Check global module index for missing imports.
1815 bool
1816 CompilerInstance::lookupMissingImports(StringRef Name,
1817                                        SourceLocation TriggerLoc) {
1818   // Look for the symbol in non-imported modules, but only if an error
1819   // actually occurred.
1820   if (!buildingModule()) {
1821     // Load global module index, or retrieve a previously loaded one.
1822     GlobalModuleIndex *GlobalIndex = loadGlobalModuleIndex(
1823       TriggerLoc);
1824 
1825     // Only if we have a global index.
1826     if (GlobalIndex) {
1827       GlobalModuleIndex::HitSet FoundModules;
1828 
1829       // Find the modules that reference the identifier.
1830       // Note that this only finds top-level modules.
1831       // We'll let diagnoseTypo find the actual declaration module.
1832       if (GlobalIndex->lookupIdentifier(Name, FoundModules))
1833         return true;
1834     }
1835   }
1836 
1837   return false;
1838 }
1839 void CompilerInstance::resetAndLeakSema() { BuryPointer(takeSema()); }
1840 
1841 void CompilerInstance::setExternalSemaSource(
1842     IntrusiveRefCntPtr<ExternalSemaSource> ESS) {
1843   ExternalSemaSrc = std::move(ESS);
1844 }
1845