xref: /llvm-project/clang/lib/Frontend/CompilerInstance.cpp (revision 3c1a41ad9969ae4e3353f5984d66af85ce56cf9a)
1 //===--- CompilerInstance.cpp ---------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "clang/Frontend/CompilerInstance.h"
11 #include "clang/AST/ASTConsumer.h"
12 #include "clang/AST/ASTContext.h"
13 #include "clang/AST/Decl.h"
14 #include "clang/Basic/Diagnostic.h"
15 #include "clang/Basic/FileManager.h"
16 #include "clang/Basic/SourceManager.h"
17 #include "clang/Basic/TargetInfo.h"
18 #include "clang/Basic/Version.h"
19 #include "clang/Config/config.h"
20 #include "clang/Frontend/ChainedDiagnosticConsumer.h"
21 #include "clang/Frontend/FrontendAction.h"
22 #include "clang/Frontend/FrontendActions.h"
23 #include "clang/Frontend/FrontendDiagnostic.h"
24 #include "clang/Frontend/LogDiagnosticPrinter.h"
25 #include "clang/Frontend/SerializedDiagnosticPrinter.h"
26 #include "clang/Frontend/TextDiagnosticPrinter.h"
27 #include "clang/Frontend/Utils.h"
28 #include "clang/Frontend/VerifyDiagnosticConsumer.h"
29 #include "clang/Lex/HeaderSearch.h"
30 #include "clang/Lex/PTHManager.h"
31 #include "clang/Lex/Preprocessor.h"
32 #include "clang/Sema/CodeCompleteConsumer.h"
33 #include "clang/Sema/Sema.h"
34 #include "clang/Serialization/ASTReader.h"
35 #include "clang/Serialization/GlobalModuleIndex.h"
36 #include "llvm/ADT/Statistic.h"
37 #include "llvm/Support/CrashRecoveryContext.h"
38 #include "llvm/Support/Errc.h"
39 #include "llvm/Support/FileSystem.h"
40 #include "llvm/Support/Host.h"
41 #include "llvm/Support/LockFileManager.h"
42 #include "llvm/Support/MemoryBuffer.h"
43 #include "llvm/Support/Path.h"
44 #include "llvm/Support/Program.h"
45 #include "llvm/Support/Signals.h"
46 #include "llvm/Support/Timer.h"
47 #include "llvm/Support/raw_ostream.h"
48 #include <sys/stat.h>
49 #include <system_error>
50 #include <time.h>
51 
52 using namespace clang;
53 
54 CompilerInstance::CompilerInstance(bool BuildingModule)
55   : ModuleLoader(BuildingModule),
56     Invocation(new CompilerInvocation()), ModuleManager(nullptr),
57     BuildGlobalModuleIndex(false), HaveFullGlobalModuleIndex(false),
58     ModuleBuildFailed(false) {
59 }
60 
61 CompilerInstance::~CompilerInstance() {
62   assert(OutputFiles.empty() && "Still output files in flight?");
63 }
64 
65 void CompilerInstance::setInvocation(CompilerInvocation *Value) {
66   Invocation = Value;
67 }
68 
69 bool CompilerInstance::shouldBuildGlobalModuleIndex() const {
70   return (BuildGlobalModuleIndex ||
71           (ModuleManager && ModuleManager->isGlobalIndexUnavailable() &&
72            getFrontendOpts().GenerateGlobalModuleIndex)) &&
73          !ModuleBuildFailed;
74 }
75 
76 void CompilerInstance::setDiagnostics(DiagnosticsEngine *Value) {
77   Diagnostics = Value;
78 }
79 
80 void CompilerInstance::setTarget(TargetInfo *Value) {
81   Target = Value;
82 }
83 
84 void CompilerInstance::setFileManager(FileManager *Value) {
85   FileMgr = Value;
86   if (Value)
87     VirtualFileSystem = Value->getVirtualFileSystem();
88   else
89     VirtualFileSystem.reset();
90 }
91 
92 void CompilerInstance::setSourceManager(SourceManager *Value) {
93   SourceMgr = Value;
94 }
95 
96 void CompilerInstance::setPreprocessor(Preprocessor *Value) { PP = Value; }
97 
98 void CompilerInstance::setASTContext(ASTContext *Value) { Context = Value; }
99 
100 void CompilerInstance::setSema(Sema *S) {
101   TheSema.reset(S);
102 }
103 
104 void CompilerInstance::setASTConsumer(std::unique_ptr<ASTConsumer> Value) {
105   Consumer = std::move(Value);
106 }
107 
108 void CompilerInstance::setCodeCompletionConsumer(CodeCompleteConsumer *Value) {
109   CompletionConsumer.reset(Value);
110 }
111 
112 std::unique_ptr<Sema> CompilerInstance::takeSema() {
113   return std::move(TheSema);
114 }
115 
116 IntrusiveRefCntPtr<ASTReader> CompilerInstance::getModuleManager() const {
117   return ModuleManager;
118 }
119 void CompilerInstance::setModuleManager(IntrusiveRefCntPtr<ASTReader> Reader) {
120   ModuleManager = Reader;
121 }
122 
123 std::shared_ptr<ModuleDependencyCollector>
124 CompilerInstance::getModuleDepCollector() const {
125   return ModuleDepCollector;
126 }
127 
128 void CompilerInstance::setModuleDepCollector(
129     std::shared_ptr<ModuleDependencyCollector> Collector) {
130   ModuleDepCollector = Collector;
131 }
132 
133 // Diagnostics
134 static void SetUpDiagnosticLog(DiagnosticOptions *DiagOpts,
135                                const CodeGenOptions *CodeGenOpts,
136                                DiagnosticsEngine &Diags) {
137   std::error_code EC;
138   std::unique_ptr<raw_ostream> StreamOwner;
139   raw_ostream *OS = &llvm::errs();
140   if (DiagOpts->DiagnosticLogFile != "-") {
141     // Create the output stream.
142     auto FileOS = llvm::make_unique<llvm::raw_fd_ostream>(
143         DiagOpts->DiagnosticLogFile, EC,
144         llvm::sys::fs::F_Append | llvm::sys::fs::F_Text);
145     if (EC) {
146       Diags.Report(diag::warn_fe_cc_log_diagnostics_failure)
147           << DiagOpts->DiagnosticLogFile << EC.message();
148     } else {
149       FileOS->SetUnbuffered();
150       FileOS->SetUseAtomicWrites(true);
151       OS = FileOS.get();
152       StreamOwner = std::move(FileOS);
153     }
154   }
155 
156   // Chain in the diagnostic client which will log the diagnostics.
157   auto Logger = llvm::make_unique<LogDiagnosticPrinter>(*OS, DiagOpts,
158                                                         std::move(StreamOwner));
159   if (CodeGenOpts)
160     Logger->setDwarfDebugFlags(CodeGenOpts->DwarfDebugFlags);
161   assert(Diags.ownsClient());
162   Diags.setClient(
163       new ChainedDiagnosticConsumer(Diags.takeClient(), std::move(Logger)));
164 }
165 
166 static void SetupSerializedDiagnostics(DiagnosticOptions *DiagOpts,
167                                        DiagnosticsEngine &Diags,
168                                        StringRef OutputFile) {
169   auto SerializedConsumer =
170       clang::serialized_diags::create(OutputFile, DiagOpts);
171 
172   if (Diags.ownsClient()) {
173     Diags.setClient(new ChainedDiagnosticConsumer(
174         Diags.takeClient(), std::move(SerializedConsumer)));
175   } else {
176     Diags.setClient(new ChainedDiagnosticConsumer(
177         Diags.getClient(), std::move(SerializedConsumer)));
178   }
179 }
180 
181 void CompilerInstance::createDiagnostics(DiagnosticConsumer *Client,
182                                          bool ShouldOwnClient) {
183   Diagnostics = createDiagnostics(&getDiagnosticOpts(), Client,
184                                   ShouldOwnClient, &getCodeGenOpts());
185 }
186 
187 IntrusiveRefCntPtr<DiagnosticsEngine>
188 CompilerInstance::createDiagnostics(DiagnosticOptions *Opts,
189                                     DiagnosticConsumer *Client,
190                                     bool ShouldOwnClient,
191                                     const CodeGenOptions *CodeGenOpts) {
192   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
193   IntrusiveRefCntPtr<DiagnosticsEngine>
194       Diags(new DiagnosticsEngine(DiagID, Opts));
195 
196   // Create the diagnostic client for reporting errors or for
197   // implementing -verify.
198   if (Client) {
199     Diags->setClient(Client, ShouldOwnClient);
200   } else
201     Diags->setClient(new TextDiagnosticPrinter(llvm::errs(), Opts));
202 
203   // Chain in -verify checker, if requested.
204   if (Opts->VerifyDiagnostics)
205     Diags->setClient(new VerifyDiagnosticConsumer(*Diags));
206 
207   // Chain in -diagnostic-log-file dumper, if requested.
208   if (!Opts->DiagnosticLogFile.empty())
209     SetUpDiagnosticLog(Opts, CodeGenOpts, *Diags);
210 
211   if (!Opts->DiagnosticSerializationFile.empty())
212     SetupSerializedDiagnostics(Opts, *Diags,
213                                Opts->DiagnosticSerializationFile);
214 
215   // Configure our handling of diagnostics.
216   ProcessWarningOptions(*Diags, *Opts);
217 
218   return Diags;
219 }
220 
221 // File Manager
222 
223 void CompilerInstance::createFileManager() {
224   if (!hasVirtualFileSystem()) {
225     // TODO: choose the virtual file system based on the CompilerInvocation.
226     setVirtualFileSystem(vfs::getRealFileSystem());
227   }
228   FileMgr = new FileManager(getFileSystemOpts(), VirtualFileSystem);
229 }
230 
231 // Source Manager
232 
233 void CompilerInstance::createSourceManager(FileManager &FileMgr) {
234   SourceMgr = new SourceManager(getDiagnostics(), FileMgr);
235 }
236 
237 // Initialize the remapping of files to alternative contents, e.g.,
238 // those specified through other files.
239 static void InitializeFileRemapping(DiagnosticsEngine &Diags,
240                                     SourceManager &SourceMgr,
241                                     FileManager &FileMgr,
242                                     const PreprocessorOptions &InitOpts) {
243   // Remap files in the source manager (with buffers).
244   for (const auto &RB : InitOpts.RemappedFileBuffers) {
245     // Create the file entry for the file that we're mapping from.
246     const FileEntry *FromFile =
247         FileMgr.getVirtualFile(RB.first, RB.second->getBufferSize(), 0);
248     if (!FromFile) {
249       Diags.Report(diag::err_fe_remap_missing_from_file) << RB.first;
250       if (!InitOpts.RetainRemappedFileBuffers)
251         delete RB.second;
252       continue;
253     }
254 
255     // Override the contents of the "from" file with the contents of
256     // the "to" file.
257     SourceMgr.overrideFileContents(FromFile, RB.second,
258                                    InitOpts.RetainRemappedFileBuffers);
259   }
260 
261   // Remap files in the source manager (with other files).
262   for (const auto &RF : InitOpts.RemappedFiles) {
263     // Find the file that we're mapping to.
264     const FileEntry *ToFile = FileMgr.getFile(RF.second);
265     if (!ToFile) {
266       Diags.Report(diag::err_fe_remap_missing_to_file) << RF.first << RF.second;
267       continue;
268     }
269 
270     // Create the file entry for the file that we're mapping from.
271     const FileEntry *FromFile =
272         FileMgr.getVirtualFile(RF.first, ToFile->getSize(), 0);
273     if (!FromFile) {
274       Diags.Report(diag::err_fe_remap_missing_from_file) << RF.first;
275       continue;
276     }
277 
278     // Override the contents of the "from" file with the contents of
279     // the "to" file.
280     SourceMgr.overrideFileContents(FromFile, ToFile);
281   }
282 
283   SourceMgr.setOverridenFilesKeepOriginalName(
284       InitOpts.RemappedFilesKeepOriginalName);
285 }
286 
287 // Preprocessor
288 
289 void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
290   const PreprocessorOptions &PPOpts = getPreprocessorOpts();
291 
292   // Create a PTH manager if we are using some form of a token cache.
293   PTHManager *PTHMgr = nullptr;
294   if (!PPOpts.TokenCache.empty())
295     PTHMgr = PTHManager::Create(PPOpts.TokenCache, getDiagnostics());
296 
297   // Create the Preprocessor.
298   HeaderSearch *HeaderInfo = new HeaderSearch(&getHeaderSearchOpts(),
299                                               getSourceManager(),
300                                               getDiagnostics(),
301                                               getLangOpts(),
302                                               &getTarget());
303   PP = new Preprocessor(&getPreprocessorOpts(), getDiagnostics(), getLangOpts(),
304                         getSourceManager(), *HeaderInfo, *this, PTHMgr,
305                         /*OwnsHeaderSearch=*/true, TUKind);
306   PP->Initialize(getTarget());
307 
308   // Note that this is different then passing PTHMgr to Preprocessor's ctor.
309   // That argument is used as the IdentifierInfoLookup argument to
310   // IdentifierTable's ctor.
311   if (PTHMgr) {
312     PTHMgr->setPreprocessor(&*PP);
313     PP->setPTHManager(PTHMgr);
314   }
315 
316   if (PPOpts.DetailedRecord)
317     PP->createPreprocessingRecord();
318 
319   // Apply remappings to the source manager.
320   InitializeFileRemapping(PP->getDiagnostics(), PP->getSourceManager(),
321                           PP->getFileManager(), PPOpts);
322 
323   // Predefine macros and configure the preprocessor.
324   InitializePreprocessor(*PP, PPOpts, getFrontendOpts());
325 
326   // Initialize the header search object.
327   ApplyHeaderSearchOptions(PP->getHeaderSearchInfo(), getHeaderSearchOpts(),
328                            PP->getLangOpts(), PP->getTargetInfo().getTriple());
329 
330   PP->setPreprocessedOutput(getPreprocessorOutputOpts().ShowCPP);
331 
332   // Set up the module path, including the hash for the
333   // module-creation options.
334   SmallString<256> SpecificModuleCache(
335                            getHeaderSearchOpts().ModuleCachePath);
336   if (!getHeaderSearchOpts().DisableModuleHash)
337     llvm::sys::path::append(SpecificModuleCache,
338                             getInvocation().getModuleHash());
339   PP->getHeaderSearchInfo().setModuleCachePath(SpecificModuleCache);
340 
341   // Handle generating dependencies, if requested.
342   const DependencyOutputOptions &DepOpts = getDependencyOutputOpts();
343   if (!DepOpts.OutputFile.empty())
344     TheDependencyFileGenerator.reset(
345         DependencyFileGenerator::CreateAndAttachToPreprocessor(*PP, DepOpts));
346   if (!DepOpts.DOTOutputFile.empty())
347     AttachDependencyGraphGen(*PP, DepOpts.DOTOutputFile,
348                              getHeaderSearchOpts().Sysroot);
349 
350   for (auto &Listener : DependencyCollectors)
351     Listener->attachToPreprocessor(*PP);
352 
353   // If we don't have a collector, but we are collecting module dependencies,
354   // then we're the top level compiler instance and need to create one.
355   if (!ModuleDepCollector && !DepOpts.ModuleDependencyOutputDir.empty())
356     ModuleDepCollector = std::make_shared<ModuleDependencyCollector>(
357         DepOpts.ModuleDependencyOutputDir);
358 
359   // Handle generating header include information, if requested.
360   if (DepOpts.ShowHeaderIncludes)
361     AttachHeaderIncludeGen(*PP);
362   if (!DepOpts.HeaderIncludeOutputFile.empty()) {
363     StringRef OutputPath = DepOpts.HeaderIncludeOutputFile;
364     if (OutputPath == "-")
365       OutputPath = "";
366     AttachHeaderIncludeGen(*PP, /*ShowAllHeaders=*/true, OutputPath,
367                            /*ShowDepth=*/false);
368   }
369 
370   if (DepOpts.PrintShowIncludes) {
371     AttachHeaderIncludeGen(*PP, /*ShowAllHeaders=*/false, /*OutputPath=*/"",
372                            /*ShowDepth=*/true, /*MSStyle=*/true);
373   }
374 }
375 
376 // ASTContext
377 
378 void CompilerInstance::createASTContext() {
379   Preprocessor &PP = getPreprocessor();
380   Context = new ASTContext(getLangOpts(), PP.getSourceManager(),
381                            PP.getIdentifierTable(), PP.getSelectorTable(),
382                            PP.getBuiltinInfo());
383   Context->InitBuiltinTypes(getTarget());
384 }
385 
386 // ExternalASTSource
387 
388 void CompilerInstance::createPCHExternalASTSource(
389     StringRef Path, bool DisablePCHValidation, bool AllowPCHWithCompilerErrors,
390     void *DeserializationListener, bool OwnDeserializationListener) {
391   IntrusiveRefCntPtr<ExternalASTSource> Source;
392   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
393   Source = createPCHExternalASTSource(
394       Path, getHeaderSearchOpts().Sysroot, DisablePCHValidation,
395       AllowPCHWithCompilerErrors, getPreprocessor(), getASTContext(),
396       DeserializationListener, OwnDeserializationListener, Preamble,
397       getFrontendOpts().UseGlobalModuleIndex);
398   ModuleManager = static_cast<ASTReader*>(Source.get());
399   getASTContext().setExternalSource(Source);
400 }
401 
402 ExternalASTSource *CompilerInstance::createPCHExternalASTSource(
403     StringRef Path, const std::string &Sysroot, bool DisablePCHValidation,
404     bool AllowPCHWithCompilerErrors, Preprocessor &PP, ASTContext &Context,
405     void *DeserializationListener, bool OwnDeserializationListener,
406     bool Preamble, bool UseGlobalModuleIndex) {
407   HeaderSearchOptions &HSOpts = PP.getHeaderSearchInfo().getHeaderSearchOpts();
408 
409   std::unique_ptr<ASTReader> Reader;
410   Reader.reset(new ASTReader(PP, Context,
411                              Sysroot.empty() ? "" : Sysroot.c_str(),
412                              DisablePCHValidation,
413                              AllowPCHWithCompilerErrors,
414                              /*AllowConfigurationMismatch*/false,
415                              HSOpts.ModulesValidateSystemHeaders,
416                              UseGlobalModuleIndex));
417 
418   Reader->setDeserializationListener(
419       static_cast<ASTDeserializationListener *>(DeserializationListener),
420       /*TakeOwnership=*/OwnDeserializationListener);
421   switch (Reader->ReadAST(Path,
422                           Preamble ? serialization::MK_Preamble
423                                    : serialization::MK_PCH,
424                           SourceLocation(),
425                           ASTReader::ARR_None)) {
426   case ASTReader::Success:
427     // Set the predefines buffer as suggested by the PCH reader. Typically, the
428     // predefines buffer will be empty.
429     PP.setPredefines(Reader->getSuggestedPredefines());
430     return Reader.release();
431 
432   case ASTReader::Failure:
433     // Unrecoverable failure: don't even try to process the input file.
434     break;
435 
436   case ASTReader::Missing:
437   case ASTReader::OutOfDate:
438   case ASTReader::VersionMismatch:
439   case ASTReader::ConfigurationMismatch:
440   case ASTReader::HadErrors:
441     // No suitable PCH file could be found. Return an error.
442     break;
443   }
444 
445   return nullptr;
446 }
447 
448 // Code Completion
449 
450 static bool EnableCodeCompletion(Preprocessor &PP,
451                                  const std::string &Filename,
452                                  unsigned Line,
453                                  unsigned Column) {
454   // Tell the source manager to chop off the given file at a specific
455   // line and column.
456   const FileEntry *Entry = PP.getFileManager().getFile(Filename);
457   if (!Entry) {
458     PP.getDiagnostics().Report(diag::err_fe_invalid_code_complete_file)
459       << Filename;
460     return true;
461   }
462 
463   // Truncate the named file at the given line/column.
464   PP.SetCodeCompletionPoint(Entry, Line, Column);
465   return false;
466 }
467 
468 void CompilerInstance::createCodeCompletionConsumer() {
469   const ParsedSourceLocation &Loc = getFrontendOpts().CodeCompletionAt;
470   if (!CompletionConsumer) {
471     setCodeCompletionConsumer(
472       createCodeCompletionConsumer(getPreprocessor(),
473                                    Loc.FileName, Loc.Line, Loc.Column,
474                                    getFrontendOpts().CodeCompleteOpts,
475                                    llvm::outs()));
476     if (!CompletionConsumer)
477       return;
478   } else if (EnableCodeCompletion(getPreprocessor(), Loc.FileName,
479                                   Loc.Line, Loc.Column)) {
480     setCodeCompletionConsumer(nullptr);
481     return;
482   }
483 
484   if (CompletionConsumer->isOutputBinary() &&
485       llvm::sys::ChangeStdoutToBinary()) {
486     getPreprocessor().getDiagnostics().Report(diag::err_fe_stdout_binary);
487     setCodeCompletionConsumer(nullptr);
488   }
489 }
490 
491 void CompilerInstance::createFrontendTimer() {
492   FrontendTimer.reset(new llvm::Timer("Clang front-end timer"));
493 }
494 
495 CodeCompleteConsumer *
496 CompilerInstance::createCodeCompletionConsumer(Preprocessor &PP,
497                                                const std::string &Filename,
498                                                unsigned Line,
499                                                unsigned Column,
500                                                const CodeCompleteOptions &Opts,
501                                                raw_ostream &OS) {
502   if (EnableCodeCompletion(PP, Filename, Line, Column))
503     return nullptr;
504 
505   // Set up the creation routine for code-completion.
506   return new PrintingCodeCompleteConsumer(Opts, OS);
507 }
508 
509 void CompilerInstance::createSema(TranslationUnitKind TUKind,
510                                   CodeCompleteConsumer *CompletionConsumer) {
511   TheSema.reset(new Sema(getPreprocessor(), getASTContext(), getASTConsumer(),
512                          TUKind, CompletionConsumer));
513 }
514 
515 // Output Files
516 
517 void CompilerInstance::addOutputFile(const OutputFile &OutFile) {
518   assert(OutFile.OS && "Attempt to add empty stream to output list!");
519   OutputFiles.push_back(OutFile);
520 }
521 
522 void CompilerInstance::clearOutputFiles(bool EraseFiles) {
523   for (std::list<OutputFile>::iterator
524          it = OutputFiles.begin(), ie = OutputFiles.end(); it != ie; ++it) {
525     delete it->OS;
526     if (!it->TempFilename.empty()) {
527       if (EraseFiles) {
528         llvm::sys::fs::remove(it->TempFilename);
529       } else {
530         SmallString<128> NewOutFile(it->Filename);
531 
532         // If '-working-directory' was passed, the output filename should be
533         // relative to that.
534         FileMgr->FixupRelativePath(NewOutFile);
535         if (std::error_code ec =
536                 llvm::sys::fs::rename(it->TempFilename, NewOutFile.str())) {
537           getDiagnostics().Report(diag::err_unable_to_rename_temp)
538             << it->TempFilename << it->Filename << ec.message();
539 
540           llvm::sys::fs::remove(it->TempFilename);
541         }
542       }
543     } else if (!it->Filename.empty() && EraseFiles)
544       llvm::sys::fs::remove(it->Filename);
545 
546   }
547   OutputFiles.clear();
548 }
549 
550 llvm::raw_fd_ostream *
551 CompilerInstance::createDefaultOutputFile(bool Binary,
552                                           StringRef InFile,
553                                           StringRef Extension) {
554   return createOutputFile(getFrontendOpts().OutputFile, Binary,
555                           /*RemoveFileOnSignal=*/true, InFile, Extension,
556                           /*UseTemporary=*/true);
557 }
558 
559 llvm::raw_null_ostream *CompilerInstance::createNullOutputFile() {
560   llvm::raw_null_ostream *OS = new llvm::raw_null_ostream();
561   addOutputFile(OutputFile("", "", OS));
562   return OS;
563 }
564 
565 llvm::raw_fd_ostream *
566 CompilerInstance::createOutputFile(StringRef OutputPath,
567                                    bool Binary, bool RemoveFileOnSignal,
568                                    StringRef InFile,
569                                    StringRef Extension,
570                                    bool UseTemporary,
571                                    bool CreateMissingDirectories) {
572   std::string OutputPathName, TempPathName;
573   std::error_code EC;
574   llvm::raw_fd_ostream *OS = createOutputFile(
575       OutputPath, EC, Binary, RemoveFileOnSignal, InFile, Extension,
576       UseTemporary, CreateMissingDirectories, &OutputPathName, &TempPathName);
577   if (!OS) {
578     getDiagnostics().Report(diag::err_fe_unable_to_open_output) << OutputPath
579                                                                 << EC.message();
580     return nullptr;
581   }
582 
583   // Add the output file -- but don't try to remove "-", since this means we are
584   // using stdin.
585   addOutputFile(OutputFile((OutputPathName != "-") ? OutputPathName : "",
586                 TempPathName, OS));
587 
588   return OS;
589 }
590 
591 llvm::raw_fd_ostream *CompilerInstance::createOutputFile(
592     StringRef OutputPath, std::error_code &Error, bool Binary,
593     bool RemoveFileOnSignal, StringRef InFile, StringRef Extension,
594     bool UseTemporary, bool CreateMissingDirectories,
595     std::string *ResultPathName, std::string *TempPathName) {
596   assert((!CreateMissingDirectories || UseTemporary) &&
597          "CreateMissingDirectories is only allowed when using temporary files");
598 
599   std::string OutFile, TempFile;
600   if (!OutputPath.empty()) {
601     OutFile = OutputPath;
602   } else if (InFile == "-") {
603     OutFile = "-";
604   } else if (!Extension.empty()) {
605     SmallString<128> Path(InFile);
606     llvm::sys::path::replace_extension(Path, Extension);
607     OutFile = Path.str();
608   } else {
609     OutFile = "-";
610   }
611 
612   std::unique_ptr<llvm::raw_fd_ostream> OS;
613   std::string OSFile;
614 
615   if (UseTemporary) {
616     if (OutFile == "-")
617       UseTemporary = false;
618     else {
619       llvm::sys::fs::file_status Status;
620       llvm::sys::fs::status(OutputPath, Status);
621       if (llvm::sys::fs::exists(Status)) {
622         // Fail early if we can't write to the final destination.
623         if (!llvm::sys::fs::can_write(OutputPath))
624           return nullptr;
625 
626         // Don't use a temporary if the output is a special file. This handles
627         // things like '-o /dev/null'
628         if (!llvm::sys::fs::is_regular_file(Status))
629           UseTemporary = false;
630       }
631     }
632   }
633 
634   if (UseTemporary) {
635     // Create a temporary file.
636     SmallString<128> TempPath;
637     TempPath = OutFile;
638     TempPath += "-%%%%%%%%";
639     int fd;
640     std::error_code EC =
641         llvm::sys::fs::createUniqueFile(TempPath.str(), fd, TempPath);
642 
643     if (CreateMissingDirectories &&
644         EC == llvm::errc::no_such_file_or_directory) {
645       StringRef Parent = llvm::sys::path::parent_path(OutputPath);
646       EC = llvm::sys::fs::create_directories(Parent);
647       if (!EC) {
648         EC = llvm::sys::fs::createUniqueFile(TempPath.str(), fd, TempPath);
649       }
650     }
651 
652     if (!EC) {
653       OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
654       OSFile = TempFile = TempPath.str();
655     }
656     // If we failed to create the temporary, fallback to writing to the file
657     // directly. This handles the corner case where we cannot write to the
658     // directory, but can write to the file.
659   }
660 
661   if (!OS) {
662     OSFile = OutFile;
663     OS.reset(new llvm::raw_fd_ostream(
664         OSFile, Error,
665         (Binary ? llvm::sys::fs::F_None : llvm::sys::fs::F_Text)));
666     if (Error)
667       return nullptr;
668   }
669 
670   // Make sure the out stream file gets removed if we crash.
671   if (RemoveFileOnSignal)
672     llvm::sys::RemoveFileOnSignal(OSFile);
673 
674   if (ResultPathName)
675     *ResultPathName = OutFile;
676   if (TempPathName)
677     *TempPathName = TempFile;
678 
679   return OS.release();
680 }
681 
682 // Initialization Utilities
683 
684 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input){
685   return InitializeSourceManager(Input, getDiagnostics(),
686                                  getFileManager(), getSourceManager(),
687                                  getFrontendOpts());
688 }
689 
690 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input,
691                                                DiagnosticsEngine &Diags,
692                                                FileManager &FileMgr,
693                                                SourceManager &SourceMgr,
694                                                const FrontendOptions &Opts) {
695   SrcMgr::CharacteristicKind
696     Kind = Input.isSystem() ? SrcMgr::C_System : SrcMgr::C_User;
697 
698   if (Input.isBuffer()) {
699     SourceMgr.setMainFileID(SourceMgr.createFileID(
700         std::unique_ptr<llvm::MemoryBuffer>(Input.getBuffer()), Kind));
701     assert(!SourceMgr.getMainFileID().isInvalid() &&
702            "Couldn't establish MainFileID!");
703     return true;
704   }
705 
706   StringRef InputFile = Input.getFile();
707 
708   // Figure out where to get and map in the main file.
709   if (InputFile != "-") {
710     const FileEntry *File = FileMgr.getFile(InputFile, /*OpenFile=*/true);
711     if (!File) {
712       Diags.Report(diag::err_fe_error_reading) << InputFile;
713       return false;
714     }
715 
716     // The natural SourceManager infrastructure can't currently handle named
717     // pipes, but we would at least like to accept them for the main
718     // file. Detect them here, read them with the volatile flag so FileMgr will
719     // pick up the correct size, and simply override their contents as we do for
720     // STDIN.
721     if (File->isNamedPipe()) {
722       auto MB = FileMgr.getBufferForFile(File, /*isVolatile=*/true);
723       if (MB) {
724         // Create a new virtual file that will have the correct size.
725         File = FileMgr.getVirtualFile(InputFile, (*MB)->getBufferSize(), 0);
726         SourceMgr.overrideFileContents(File, std::move(*MB));
727       } else {
728         Diags.Report(diag::err_cannot_open_file) << InputFile
729                                                  << MB.getError().message();
730         return false;
731       }
732     }
733 
734     SourceMgr.setMainFileID(
735         SourceMgr.createFileID(File, SourceLocation(), Kind));
736   } else {
737     llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> SBOrErr =
738         llvm::MemoryBuffer::getSTDIN();
739     if (std::error_code EC = SBOrErr.getError()) {
740       Diags.Report(diag::err_fe_error_reading_stdin) << EC.message();
741       return false;
742     }
743     std::unique_ptr<llvm::MemoryBuffer> SB = std::move(SBOrErr.get());
744 
745     const FileEntry *File = FileMgr.getVirtualFile(SB->getBufferIdentifier(),
746                                                    SB->getBufferSize(), 0);
747     SourceMgr.setMainFileID(
748         SourceMgr.createFileID(File, SourceLocation(), Kind));
749     SourceMgr.overrideFileContents(File, std::move(SB));
750   }
751 
752   assert(!SourceMgr.getMainFileID().isInvalid() &&
753          "Couldn't establish MainFileID!");
754   return true;
755 }
756 
757 // High-Level Operations
758 
759 bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
760   assert(hasDiagnostics() && "Diagnostics engine is not initialized!");
761   assert(!getFrontendOpts().ShowHelp && "Client must handle '-help'!");
762   assert(!getFrontendOpts().ShowVersion && "Client must handle '-version'!");
763 
764   // FIXME: Take this as an argument, once all the APIs we used have moved to
765   // taking it as an input instead of hard-coding llvm::errs.
766   raw_ostream &OS = llvm::errs();
767 
768   // Create the target instance.
769   setTarget(TargetInfo::CreateTargetInfo(getDiagnostics(),
770                                          getInvocation().TargetOpts));
771   if (!hasTarget())
772     return false;
773 
774   // Inform the target of the language options.
775   //
776   // FIXME: We shouldn't need to do this, the target should be immutable once
777   // created. This complexity should be lifted elsewhere.
778   getTarget().adjust(getLangOpts());
779 
780   // rewriter project will change target built-in bool type from its default.
781   if (getFrontendOpts().ProgramAction == frontend::RewriteObjC)
782     getTarget().noSignedCharForObjCBool();
783 
784   // Validate/process some options.
785   if (getHeaderSearchOpts().Verbose)
786     OS << "clang -cc1 version " CLANG_VERSION_STRING
787        << " based upon " << BACKEND_PACKAGE_STRING
788        << " default target " << llvm::sys::getDefaultTargetTriple() << "\n";
789 
790   if (getFrontendOpts().ShowTimers)
791     createFrontendTimer();
792 
793   if (getFrontendOpts().ShowStats)
794     llvm::EnableStatistics();
795 
796   for (unsigned i = 0, e = getFrontendOpts().Inputs.size(); i != e; ++i) {
797     // Reset the ID tables if we are reusing the SourceManager and parsing
798     // regular files.
799     if (hasSourceManager() && !Act.isModelParsingAction())
800       getSourceManager().clearIDTables();
801 
802     if (Act.BeginSourceFile(*this, getFrontendOpts().Inputs[i])) {
803       Act.Execute();
804       Act.EndSourceFile();
805     }
806   }
807 
808   // Notify the diagnostic client that all files were processed.
809   getDiagnostics().getClient()->finish();
810 
811   if (getDiagnosticOpts().ShowCarets) {
812     // We can have multiple diagnostics sharing one diagnostic client.
813     // Get the total number of warnings/errors from the client.
814     unsigned NumWarnings = getDiagnostics().getClient()->getNumWarnings();
815     unsigned NumErrors = getDiagnostics().getClient()->getNumErrors();
816 
817     if (NumWarnings)
818       OS << NumWarnings << " warning" << (NumWarnings == 1 ? "" : "s");
819     if (NumWarnings && NumErrors)
820       OS << " and ";
821     if (NumErrors)
822       OS << NumErrors << " error" << (NumErrors == 1 ? "" : "s");
823     if (NumWarnings || NumErrors)
824       OS << " generated.\n";
825   }
826 
827   if (getFrontendOpts().ShowStats && hasFileManager()) {
828     getFileManager().PrintStats();
829     OS << "\n";
830   }
831 
832   return !getDiagnostics().getClient()->getNumErrors();
833 }
834 
835 /// \brief Determine the appropriate source input kind based on language
836 /// options.
837 static InputKind getSourceInputKindFromOptions(const LangOptions &LangOpts) {
838   if (LangOpts.OpenCL)
839     return IK_OpenCL;
840   if (LangOpts.CUDA)
841     return IK_CUDA;
842   if (LangOpts.ObjC1)
843     return LangOpts.CPlusPlus? IK_ObjCXX : IK_ObjC;
844   return LangOpts.CPlusPlus? IK_CXX : IK_C;
845 }
846 
847 /// \brief Compile a module file for the given module, using the options
848 /// provided by the importing compiler instance. Returns true if the module
849 /// was built without errors.
850 static bool compileModuleImpl(CompilerInstance &ImportingInstance,
851                               SourceLocation ImportLoc,
852                               Module *Module,
853                               StringRef ModuleFileName) {
854   ModuleMap &ModMap
855     = ImportingInstance.getPreprocessor().getHeaderSearchInfo().getModuleMap();
856 
857   // Construct a compiler invocation for creating this module.
858   IntrusiveRefCntPtr<CompilerInvocation> Invocation
859     (new CompilerInvocation(ImportingInstance.getInvocation()));
860 
861   PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
862 
863   // For any options that aren't intended to affect how a module is built,
864   // reset them to their default values.
865   Invocation->getLangOpts()->resetNonModularOptions();
866   PPOpts.resetNonModularOptions();
867 
868   // Remove any macro definitions that are explicitly ignored by the module.
869   // They aren't supposed to affect how the module is built anyway.
870   const HeaderSearchOptions &HSOpts = Invocation->getHeaderSearchOpts();
871   PPOpts.Macros.erase(
872       std::remove_if(PPOpts.Macros.begin(), PPOpts.Macros.end(),
873                      [&HSOpts](const std::pair<std::string, bool> &def) {
874         StringRef MacroDef = def.first;
875         return HSOpts.ModulesIgnoreMacros.count(MacroDef.split('=').first) > 0;
876       }),
877       PPOpts.Macros.end());
878 
879   // Note the name of the module we're building.
880   Invocation->getLangOpts()->CurrentModule = Module->getTopLevelModuleName();
881 
882   // Make sure that the failed-module structure has been allocated in
883   // the importing instance, and propagate the pointer to the newly-created
884   // instance.
885   PreprocessorOptions &ImportingPPOpts
886     = ImportingInstance.getInvocation().getPreprocessorOpts();
887   if (!ImportingPPOpts.FailedModules)
888     ImportingPPOpts.FailedModules = new PreprocessorOptions::FailedModulesSet;
889   PPOpts.FailedModules = ImportingPPOpts.FailedModules;
890 
891   // If there is a module map file, build the module using the module map.
892   // Set up the inputs/outputs so that we build the module from its umbrella
893   // header.
894   FrontendOptions &FrontendOpts = Invocation->getFrontendOpts();
895   FrontendOpts.OutputFile = ModuleFileName.str();
896   FrontendOpts.DisableFree = false;
897   FrontendOpts.GenerateGlobalModuleIndex = false;
898   FrontendOpts.Inputs.clear();
899   InputKind IK = getSourceInputKindFromOptions(*Invocation->getLangOpts());
900 
901   // Don't free the remapped file buffers; they are owned by our caller.
902   PPOpts.RetainRemappedFileBuffers = true;
903 
904   Invocation->getDiagnosticOpts().VerifyDiagnostics = 0;
905   assert(ImportingInstance.getInvocation().getModuleHash() ==
906          Invocation->getModuleHash() && "Module hash mismatch!");
907 
908   // Construct a compiler instance that will be used to actually create the
909   // module.
910   CompilerInstance Instance(/*BuildingModule=*/true);
911   Instance.setInvocation(&*Invocation);
912 
913   Instance.createDiagnostics(new ForwardingDiagnosticConsumer(
914                                    ImportingInstance.getDiagnosticClient()),
915                              /*ShouldOwnClient=*/true);
916 
917   Instance.setVirtualFileSystem(&ImportingInstance.getVirtualFileSystem());
918 
919   // Note that this module is part of the module build stack, so that we
920   // can detect cycles in the module graph.
921   Instance.setFileManager(&ImportingInstance.getFileManager());
922   Instance.createSourceManager(Instance.getFileManager());
923   SourceManager &SourceMgr = Instance.getSourceManager();
924   SourceMgr.setModuleBuildStack(
925     ImportingInstance.getSourceManager().getModuleBuildStack());
926   SourceMgr.pushModuleBuildStack(Module->getTopLevelModuleName(),
927     FullSourceLoc(ImportLoc, ImportingInstance.getSourceManager()));
928 
929   // If we're collecting module dependencies, we need to share a collector
930   // between all of the module CompilerInstances.
931   Instance.setModuleDepCollector(ImportingInstance.getModuleDepCollector());
932 
933   // Get or create the module map that we'll use to build this module.
934   std::string InferredModuleMapContent;
935   if (const FileEntry *ModuleMapFile =
936           ModMap.getContainingModuleMapFile(Module)) {
937     // Use the module map where this module resides.
938     FrontendOpts.Inputs.push_back(
939         FrontendInputFile(ModuleMapFile->getName(), IK));
940   } else {
941     llvm::raw_string_ostream OS(InferredModuleMapContent);
942     Module->print(OS);
943     OS.flush();
944     FrontendOpts.Inputs.push_back(
945         FrontendInputFile("__inferred_module.map", IK));
946 
947     std::unique_ptr<llvm::MemoryBuffer> ModuleMapBuffer =
948         llvm::MemoryBuffer::getMemBuffer(InferredModuleMapContent);
949     ModuleMapFile = Instance.getFileManager().getVirtualFile(
950         "__inferred_module.map", InferredModuleMapContent.size(), 0);
951     SourceMgr.overrideFileContents(ModuleMapFile, std::move(ModuleMapBuffer));
952   }
953 
954   // Construct a module-generating action. Passing through the module map is
955   // safe because the FileManager is shared between the compiler instances.
956   GenerateModuleAction CreateModuleAction(
957       ModMap.getModuleMapFileForUniquing(Module), Module->IsSystem);
958 
959   ImportingInstance.getDiagnostics().Report(ImportLoc,
960                                             diag::remark_module_build)
961     << Module->Name << ModuleFileName;
962 
963   // Execute the action to actually build the module in-place. Use a separate
964   // thread so that we get a stack large enough.
965   const unsigned ThreadStackSize = 8 << 20;
966   llvm::CrashRecoveryContext CRC;
967   CRC.RunSafelyOnThread([&]() { Instance.ExecuteAction(CreateModuleAction); },
968                         ThreadStackSize);
969 
970   ImportingInstance.getDiagnostics().Report(ImportLoc,
971                                             diag::remark_module_build_done)
972     << Module->Name;
973 
974   // Delete the temporary module map file.
975   // FIXME: Even though we're executing under crash protection, it would still
976   // be nice to do this with RemoveFileOnSignal when we can. However, that
977   // doesn't make sense for all clients, so clean this up manually.
978   Instance.clearOutputFiles(/*EraseFiles=*/true);
979 
980   // We've rebuilt a module. If we're allowed to generate or update the global
981   // module index, record that fact in the importing compiler instance.
982   if (ImportingInstance.getFrontendOpts().GenerateGlobalModuleIndex) {
983     ImportingInstance.setBuildGlobalModuleIndex(true);
984   }
985 
986   return !Instance.getDiagnostics().hasErrorOccurred();
987 }
988 
989 static bool compileAndLoadModule(CompilerInstance &ImportingInstance,
990                                  SourceLocation ImportLoc,
991                                  SourceLocation ModuleNameLoc, Module *Module,
992                                  StringRef ModuleFileName) {
993   DiagnosticsEngine &Diags = ImportingInstance.getDiagnostics();
994 
995   auto diagnoseBuildFailure = [&] {
996     Diags.Report(ModuleNameLoc, diag::err_module_not_built)
997         << Module->Name << SourceRange(ImportLoc, ModuleNameLoc);
998   };
999 
1000   // FIXME: have LockFileManager return an error_code so that we can
1001   // avoid the mkdir when the directory already exists.
1002   StringRef Dir = llvm::sys::path::parent_path(ModuleFileName);
1003   llvm::sys::fs::create_directories(Dir);
1004 
1005   while (1) {
1006     unsigned ModuleLoadCapabilities = ASTReader::ARR_Missing;
1007     llvm::LockFileManager Locked(ModuleFileName);
1008     switch (Locked) {
1009     case llvm::LockFileManager::LFS_Error:
1010       Diags.Report(ModuleNameLoc, diag::err_module_lock_failure)
1011           << Module->Name;
1012       return false;
1013 
1014     case llvm::LockFileManager::LFS_Owned:
1015       // We're responsible for building the module ourselves.
1016       if (!compileModuleImpl(ImportingInstance, ModuleNameLoc, Module,
1017                              ModuleFileName)) {
1018         diagnoseBuildFailure();
1019         return false;
1020       }
1021       break;
1022 
1023     case llvm::LockFileManager::LFS_Shared:
1024       // Someone else is responsible for building the module. Wait for them to
1025       // finish.
1026       if (Locked.waitForUnlock() == llvm::LockFileManager::Res_OwnerDied)
1027         continue; // try again to get the lock.
1028       ModuleLoadCapabilities |= ASTReader::ARR_OutOfDate;
1029       break;
1030     }
1031 
1032     // Try to read the module file, now that we've compiled it.
1033     ASTReader::ASTReadResult ReadResult =
1034         ImportingInstance.getModuleManager()->ReadAST(
1035             ModuleFileName, serialization::MK_ImplicitModule, ImportLoc,
1036             ModuleLoadCapabilities);
1037 
1038     if (ReadResult == ASTReader::OutOfDate &&
1039         Locked == llvm::LockFileManager::LFS_Shared) {
1040       // The module may be out of date in the presence of file system races,
1041       // or if one of its imports depends on header search paths that are not
1042       // consistent with this ImportingInstance.  Try again...
1043       continue;
1044     } else if (ReadResult == ASTReader::Missing) {
1045       diagnoseBuildFailure();
1046     } else if (ReadResult != ASTReader::Success &&
1047                !Diags.hasErrorOccurred()) {
1048       // The ASTReader didn't diagnose the error, so conservatively report it.
1049       diagnoseBuildFailure();
1050     }
1051     return ReadResult == ASTReader::Success;
1052   }
1053 }
1054 
1055 /// \brief Diagnose differences between the current definition of the given
1056 /// configuration macro and the definition provided on the command line.
1057 static void checkConfigMacro(Preprocessor &PP, StringRef ConfigMacro,
1058                              Module *Mod, SourceLocation ImportLoc) {
1059   IdentifierInfo *Id = PP.getIdentifierInfo(ConfigMacro);
1060   SourceManager &SourceMgr = PP.getSourceManager();
1061 
1062   // If this identifier has never had a macro definition, then it could
1063   // not have changed.
1064   if (!Id->hadMacroDefinition())
1065     return;
1066 
1067   // If this identifier does not currently have a macro definition,
1068   // check whether it had one on the command line.
1069   if (!Id->hasMacroDefinition()) {
1070     MacroDirective::DefInfo LatestDef =
1071         PP.getMacroDirectiveHistory(Id)->getDefinition();
1072     for (MacroDirective::DefInfo Def = LatestDef; Def;
1073            Def = Def.getPreviousDefinition()) {
1074       FileID FID = SourceMgr.getFileID(Def.getLocation());
1075       if (FID.isInvalid())
1076         continue;
1077 
1078       // We only care about the predefines buffer.
1079       if (FID != PP.getPredefinesFileID())
1080         continue;
1081 
1082       // This macro was defined on the command line, then #undef'd later.
1083       // Complain.
1084       PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
1085         << true << ConfigMacro << Mod->getFullModuleName();
1086       if (LatestDef.isUndefined())
1087         PP.Diag(LatestDef.getUndefLocation(), diag::note_module_def_undef_here)
1088           << true;
1089       return;
1090     }
1091 
1092     // Okay: no definition in the predefines buffer.
1093     return;
1094   }
1095 
1096   // This identifier has a macro definition. Check whether we had a definition
1097   // on the command line.
1098   MacroDirective::DefInfo LatestDef =
1099       PP.getMacroDirectiveHistory(Id)->getDefinition();
1100   MacroDirective::DefInfo PredefinedDef;
1101   for (MacroDirective::DefInfo Def = LatestDef; Def;
1102          Def = Def.getPreviousDefinition()) {
1103     FileID FID = SourceMgr.getFileID(Def.getLocation());
1104     if (FID.isInvalid())
1105       continue;
1106 
1107     // We only care about the predefines buffer.
1108     if (FID != PP.getPredefinesFileID())
1109       continue;
1110 
1111     PredefinedDef = Def;
1112     break;
1113   }
1114 
1115   // If there was no definition for this macro in the predefines buffer,
1116   // complain.
1117   if (!PredefinedDef ||
1118       (!PredefinedDef.getLocation().isValid() &&
1119        PredefinedDef.getUndefLocation().isValid())) {
1120     PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
1121       << false << ConfigMacro << Mod->getFullModuleName();
1122     PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
1123       << false;
1124     return;
1125   }
1126 
1127   // If the current macro definition is the same as the predefined macro
1128   // definition, it's okay.
1129   if (LatestDef.getMacroInfo() == PredefinedDef.getMacroInfo() ||
1130       LatestDef.getMacroInfo()->isIdenticalTo(*PredefinedDef.getMacroInfo(),PP,
1131                                               /*Syntactically=*/true))
1132     return;
1133 
1134   // The macro definitions differ.
1135   PP.Diag(ImportLoc, diag::warn_module_config_macro_undef)
1136     << false << ConfigMacro << Mod->getFullModuleName();
1137   PP.Diag(LatestDef.getLocation(), diag::note_module_def_undef_here)
1138     << false;
1139 }
1140 
1141 /// \brief Write a new timestamp file with the given path.
1142 static void writeTimestampFile(StringRef TimestampFile) {
1143   std::error_code EC;
1144   llvm::raw_fd_ostream Out(TimestampFile.str(), EC, llvm::sys::fs::F_None);
1145 }
1146 
1147 /// \brief Prune the module cache of modules that haven't been accessed in
1148 /// a long time.
1149 static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
1150   struct stat StatBuf;
1151   llvm::SmallString<128> TimestampFile;
1152   TimestampFile = HSOpts.ModuleCachePath;
1153   llvm::sys::path::append(TimestampFile, "modules.timestamp");
1154 
1155   // Try to stat() the timestamp file.
1156   if (::stat(TimestampFile.c_str(), &StatBuf)) {
1157     // If the timestamp file wasn't there, create one now.
1158     if (errno == ENOENT) {
1159       writeTimestampFile(TimestampFile);
1160     }
1161     return;
1162   }
1163 
1164   // Check whether the time stamp is older than our pruning interval.
1165   // If not, do nothing.
1166   time_t TimeStampModTime = StatBuf.st_mtime;
1167   time_t CurrentTime = time(nullptr);
1168   if (CurrentTime - TimeStampModTime <= time_t(HSOpts.ModuleCachePruneInterval))
1169     return;
1170 
1171   // Write a new timestamp file so that nobody else attempts to prune.
1172   // There is a benign race condition here, if two Clang instances happen to
1173   // notice at the same time that the timestamp is out-of-date.
1174   writeTimestampFile(TimestampFile);
1175 
1176   // Walk the entire module cache, looking for unused module files and module
1177   // indices.
1178   std::error_code EC;
1179   SmallString<128> ModuleCachePathNative;
1180   llvm::sys::path::native(HSOpts.ModuleCachePath, ModuleCachePathNative);
1181   for (llvm::sys::fs::directory_iterator
1182          Dir(ModuleCachePathNative.str(), EC), DirEnd;
1183        Dir != DirEnd && !EC; Dir.increment(EC)) {
1184     // If we don't have a directory, there's nothing to look into.
1185     if (!llvm::sys::fs::is_directory(Dir->path()))
1186       continue;
1187 
1188     // Walk all of the files within this directory.
1189     for (llvm::sys::fs::directory_iterator File(Dir->path(), EC), FileEnd;
1190          File != FileEnd && !EC; File.increment(EC)) {
1191       // We only care about module and global module index files.
1192       StringRef Extension = llvm::sys::path::extension(File->path());
1193       if (Extension != ".pcm" && Extension != ".timestamp" &&
1194           llvm::sys::path::filename(File->path()) != "modules.idx")
1195         continue;
1196 
1197       // Look at this file. If we can't stat it, there's nothing interesting
1198       // there.
1199       if (::stat(File->path().c_str(), &StatBuf))
1200         continue;
1201 
1202       // If the file has been used recently enough, leave it there.
1203       time_t FileAccessTime = StatBuf.st_atime;
1204       if (CurrentTime - FileAccessTime <=
1205               time_t(HSOpts.ModuleCachePruneAfter)) {
1206         continue;
1207       }
1208 
1209       // Remove the file.
1210       llvm::sys::fs::remove(File->path());
1211 
1212       // Remove the timestamp file.
1213       std::string TimpestampFilename = File->path() + ".timestamp";
1214       llvm::sys::fs::remove(TimpestampFilename);
1215     }
1216 
1217     // If we removed all of the files in the directory, remove the directory
1218     // itself.
1219     if (llvm::sys::fs::directory_iterator(Dir->path(), EC) ==
1220             llvm::sys::fs::directory_iterator() && !EC)
1221       llvm::sys::fs::remove(Dir->path());
1222   }
1223 }
1224 
1225 void CompilerInstance::createModuleManager() {
1226   if (!ModuleManager) {
1227     if (!hasASTContext())
1228       createASTContext();
1229 
1230     // If we're not recursively building a module, check whether we
1231     // need to prune the module cache.
1232     if (getSourceManager().getModuleBuildStack().empty() &&
1233         getHeaderSearchOpts().ModuleCachePruneInterval > 0 &&
1234         getHeaderSearchOpts().ModuleCachePruneAfter > 0) {
1235       pruneModuleCache(getHeaderSearchOpts());
1236     }
1237 
1238     HeaderSearchOptions &HSOpts = getHeaderSearchOpts();
1239     std::string Sysroot = HSOpts.Sysroot;
1240     const PreprocessorOptions &PPOpts = getPreprocessorOpts();
1241     ModuleManager = new ASTReader(getPreprocessor(), *Context,
1242                                   Sysroot.empty() ? "" : Sysroot.c_str(),
1243                                   PPOpts.DisablePCHValidation,
1244                                   /*AllowASTWithCompilerErrors=*/false,
1245                                   /*AllowConfigurationMismatch=*/false,
1246                                   HSOpts.ModulesValidateSystemHeaders,
1247                                   getFrontendOpts().UseGlobalModuleIndex);
1248     if (hasASTConsumer()) {
1249       ModuleManager->setDeserializationListener(
1250         getASTConsumer().GetASTDeserializationListener());
1251       getASTContext().setASTMutationListener(
1252         getASTConsumer().GetASTMutationListener());
1253     }
1254     getASTContext().setExternalSource(ModuleManager);
1255     if (hasSema())
1256       ModuleManager->InitializeSema(getSema());
1257     if (hasASTConsumer())
1258       ModuleManager->StartTranslationUnit(&getASTConsumer());
1259   }
1260 }
1261 
1262 bool CompilerInstance::loadModuleFile(StringRef FileName) {
1263   // Helper to recursively read the module names for all modules we're adding.
1264   // We mark these as known and redirect any attempt to load that module to
1265   // the files we were handed.
1266   struct ReadModuleNames : ASTReaderListener {
1267     CompilerInstance &CI;
1268     std::vector<StringRef> ModuleFileStack;
1269     bool Failed;
1270     bool TopFileIsModule;
1271 
1272     ReadModuleNames(CompilerInstance &CI)
1273         : CI(CI), Failed(false), TopFileIsModule(false) {}
1274 
1275     bool needsImportVisitation() const override { return true; }
1276 
1277     void visitImport(StringRef FileName) override {
1278       ModuleFileStack.push_back(FileName);
1279       if (ASTReader::readASTFileControlBlock(FileName, CI.getFileManager(),
1280                                              *this)) {
1281         CI.getDiagnostics().Report(SourceLocation(),
1282                                    diag::err_module_file_not_found)
1283             << FileName;
1284         // FIXME: Produce a note stack explaining how we got here.
1285         Failed = true;
1286       }
1287       ModuleFileStack.pop_back();
1288     }
1289 
1290     void ReadModuleName(StringRef ModuleName) override {
1291       if (ModuleFileStack.size() == 1)
1292         TopFileIsModule = true;
1293 
1294       auto &ModuleFile = CI.ModuleFileOverrides[ModuleName];
1295       if (!ModuleFile.empty() && ModuleFile != ModuleFileStack.back())
1296         CI.getDiagnostics().Report(SourceLocation(),
1297                                    diag::err_conflicting_module_files)
1298             << ModuleName << ModuleFile << ModuleFileStack.back();
1299       ModuleFile = ModuleFileStack.back();
1300     }
1301   } RMN(*this);
1302 
1303   RMN.visitImport(FileName);
1304 
1305   if (RMN.Failed)
1306     return false;
1307 
1308   // If we never found a module name for the top file, then it's not a module,
1309   // it's a PCH or preamble or something.
1310   if (!RMN.TopFileIsModule) {
1311     getDiagnostics().Report(SourceLocation(), diag::err_module_file_not_module)
1312       << FileName;
1313     return false;
1314   }
1315 
1316   return true;
1317 }
1318 
1319 ModuleLoadResult
1320 CompilerInstance::loadModule(SourceLocation ImportLoc,
1321                              ModuleIdPath Path,
1322                              Module::NameVisibilityKind Visibility,
1323                              bool IsInclusionDirective) {
1324   // Determine what file we're searching from.
1325   StringRef ModuleName = Path[0].first->getName();
1326   SourceLocation ModuleNameLoc = Path[0].second;
1327 
1328   // If we've already handled this import, just return the cached result.
1329   // This one-element cache is important to eliminate redundant diagnostics
1330   // when both the preprocessor and parser see the same import declaration.
1331   if (!ImportLoc.isInvalid() && LastModuleImportLoc == ImportLoc) {
1332     // Make the named module visible.
1333     if (LastModuleImportResult && ModuleName != getLangOpts().CurrentModule &&
1334         ModuleName != getLangOpts().ImplementationOfModule)
1335       ModuleManager->makeModuleVisible(LastModuleImportResult, Visibility,
1336                                        ImportLoc, /*Complain=*/false);
1337     return LastModuleImportResult;
1338   }
1339 
1340   clang::Module *Module = nullptr;
1341 
1342   // If we don't already have information on this module, load the module now.
1343   llvm::DenseMap<const IdentifierInfo *, clang::Module *>::iterator Known
1344     = KnownModules.find(Path[0].first);
1345   if (Known != KnownModules.end()) {
1346     // Retrieve the cached top-level module.
1347     Module = Known->second;
1348   } else if (ModuleName == getLangOpts().CurrentModule ||
1349              ModuleName == getLangOpts().ImplementationOfModule) {
1350     // This is the module we're building.
1351     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
1352     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1353   } else {
1354     // Search for a module with the given name.
1355     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
1356     if (!Module) {
1357       getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_found)
1358       << ModuleName
1359       << SourceRange(ImportLoc, ModuleNameLoc);
1360       ModuleBuildFailed = true;
1361       return ModuleLoadResult();
1362     }
1363 
1364     auto Override = ModuleFileOverrides.find(ModuleName);
1365     bool Explicit = Override != ModuleFileOverrides.end();
1366 
1367     std::string ModuleFileName =
1368         Explicit ? Override->second
1369                  : PP->getHeaderSearchInfo().getModuleFileName(Module);
1370 
1371     // If we don't already have an ASTReader, create one now.
1372     if (!ModuleManager)
1373       createModuleManager();
1374 
1375     if (TheDependencyFileGenerator)
1376       TheDependencyFileGenerator->AttachToASTReader(*ModuleManager);
1377 
1378     if (ModuleDepCollector)
1379       ModuleDepCollector->attachToASTReader(*ModuleManager);
1380 
1381     for (auto &Listener : DependencyCollectors)
1382       Listener->attachToASTReader(*ModuleManager);
1383 
1384     // Try to load the module file.
1385     unsigned ARRFlags =
1386         Explicit ? 0 : ASTReader::ARR_OutOfDate | ASTReader::ARR_Missing;
1387     switch (ModuleManager->ReadAST(ModuleFileName,
1388                                    Explicit ? serialization::MK_ExplicitModule
1389                                             : serialization::MK_ImplicitModule,
1390                                    ImportLoc, ARRFlags)) {
1391     case ASTReader::Success:
1392       break;
1393 
1394     case ASTReader::OutOfDate:
1395     case ASTReader::Missing: {
1396       if (Explicit) {
1397         // ReadAST has already complained for us.
1398         ModuleLoader::HadFatalFailure = true;
1399         KnownModules[Path[0].first] = nullptr;
1400         return ModuleLoadResult();
1401       }
1402 
1403       // The module file is missing or out-of-date. Build it.
1404       assert(Module && "missing module file");
1405       // Check whether there is a cycle in the module graph.
1406       ModuleBuildStack ModPath = getSourceManager().getModuleBuildStack();
1407       ModuleBuildStack::iterator Pos = ModPath.begin(), PosEnd = ModPath.end();
1408       for (; Pos != PosEnd; ++Pos) {
1409         if (Pos->first == ModuleName)
1410           break;
1411       }
1412 
1413       if (Pos != PosEnd) {
1414         SmallString<256> CyclePath;
1415         for (; Pos != PosEnd; ++Pos) {
1416           CyclePath += Pos->first;
1417           CyclePath += " -> ";
1418         }
1419         CyclePath += ModuleName;
1420 
1421         getDiagnostics().Report(ModuleNameLoc, diag::err_module_cycle)
1422           << ModuleName << CyclePath;
1423         return ModuleLoadResult();
1424       }
1425 
1426       // Check whether we have already attempted to build this module (but
1427       // failed).
1428       if (getPreprocessorOpts().FailedModules &&
1429           getPreprocessorOpts().FailedModules->hasAlreadyFailed(ModuleName)) {
1430         getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_built)
1431           << ModuleName
1432           << SourceRange(ImportLoc, ModuleNameLoc);
1433         ModuleBuildFailed = true;
1434         return ModuleLoadResult();
1435       }
1436 
1437       // Try to compile and then load the module.
1438       if (!compileAndLoadModule(*this, ImportLoc, ModuleNameLoc, Module,
1439                                 ModuleFileName)) {
1440         assert(getDiagnostics().hasErrorOccurred() &&
1441                "undiagnosed error in compileAndLoadModule");
1442         if (getPreprocessorOpts().FailedModules)
1443           getPreprocessorOpts().FailedModules->addFailed(ModuleName);
1444         KnownModules[Path[0].first] = nullptr;
1445         ModuleBuildFailed = true;
1446         return ModuleLoadResult();
1447       }
1448 
1449       // Okay, we've rebuilt and now loaded the module.
1450       break;
1451     }
1452 
1453     case ASTReader::VersionMismatch:
1454     case ASTReader::ConfigurationMismatch:
1455     case ASTReader::HadErrors:
1456       ModuleLoader::HadFatalFailure = true;
1457       // FIXME: The ASTReader will already have complained, but can we showhorn
1458       // that diagnostic information into a more useful form?
1459       KnownModules[Path[0].first] = nullptr;
1460       return ModuleLoadResult();
1461 
1462     case ASTReader::Failure:
1463       ModuleLoader::HadFatalFailure = true;
1464       // Already complained, but note now that we failed.
1465       KnownModules[Path[0].first] = nullptr;
1466       ModuleBuildFailed = true;
1467       return ModuleLoadResult();
1468     }
1469 
1470     // Cache the result of this top-level module lookup for later.
1471     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1472   }
1473 
1474   // If we never found the module, fail.
1475   if (!Module)
1476     return ModuleLoadResult();
1477 
1478   // Verify that the rest of the module path actually corresponds to
1479   // a submodule.
1480   if (Path.size() > 1) {
1481     for (unsigned I = 1, N = Path.size(); I != N; ++I) {
1482       StringRef Name = Path[I].first->getName();
1483       clang::Module *Sub = Module->findSubmodule(Name);
1484 
1485       if (!Sub) {
1486         // Attempt to perform typo correction to find a module name that works.
1487         SmallVector<StringRef, 2> Best;
1488         unsigned BestEditDistance = (std::numeric_limits<unsigned>::max)();
1489 
1490         for (clang::Module::submodule_iterator J = Module->submodule_begin(),
1491                                             JEnd = Module->submodule_end();
1492              J != JEnd; ++J) {
1493           unsigned ED = Name.edit_distance((*J)->Name,
1494                                            /*AllowReplacements=*/true,
1495                                            BestEditDistance);
1496           if (ED <= BestEditDistance) {
1497             if (ED < BestEditDistance) {
1498               Best.clear();
1499               BestEditDistance = ED;
1500             }
1501 
1502             Best.push_back((*J)->Name);
1503           }
1504         }
1505 
1506         // If there was a clear winner, user it.
1507         if (Best.size() == 1) {
1508           getDiagnostics().Report(Path[I].second,
1509                                   diag::err_no_submodule_suggest)
1510             << Path[I].first << Module->getFullModuleName() << Best[0]
1511             << SourceRange(Path[0].second, Path[I-1].second)
1512             << FixItHint::CreateReplacement(SourceRange(Path[I].second),
1513                                             Best[0]);
1514 
1515           Sub = Module->findSubmodule(Best[0]);
1516         }
1517       }
1518 
1519       if (!Sub) {
1520         // No submodule by this name. Complain, and don't look for further
1521         // submodules.
1522         getDiagnostics().Report(Path[I].second, diag::err_no_submodule)
1523           << Path[I].first << Module->getFullModuleName()
1524           << SourceRange(Path[0].second, Path[I-1].second);
1525         break;
1526       }
1527 
1528       Module = Sub;
1529     }
1530   }
1531 
1532   // Don't make the module visible if we are in the implementation.
1533   if (ModuleName == getLangOpts().ImplementationOfModule)
1534     return ModuleLoadResult(Module, false);
1535 
1536   // Make the named module visible, if it's not already part of the module
1537   // we are parsing.
1538   if (ModuleName != getLangOpts().CurrentModule) {
1539     if (!Module->IsFromModuleFile) {
1540       // We have an umbrella header or directory that doesn't actually include
1541       // all of the headers within the directory it covers. Complain about
1542       // this missing submodule and recover by forgetting that we ever saw
1543       // this submodule.
1544       // FIXME: Should we detect this at module load time? It seems fairly
1545       // expensive (and rare).
1546       getDiagnostics().Report(ImportLoc, diag::warn_missing_submodule)
1547         << Module->getFullModuleName()
1548         << SourceRange(Path.front().second, Path.back().second);
1549 
1550       return ModuleLoadResult(nullptr, true);
1551     }
1552 
1553     // Check whether this module is available.
1554     clang::Module::Requirement Requirement;
1555     clang::Module::UnresolvedHeaderDirective MissingHeader;
1556     if (!Module->isAvailable(getLangOpts(), getTarget(), Requirement,
1557                              MissingHeader)) {
1558       if (MissingHeader.FileNameLoc.isValid()) {
1559         getDiagnostics().Report(MissingHeader.FileNameLoc,
1560                                 diag::err_module_header_missing)
1561           << MissingHeader.IsUmbrella << MissingHeader.FileName;
1562       } else {
1563         getDiagnostics().Report(ImportLoc, diag::err_module_unavailable)
1564           << Module->getFullModuleName()
1565           << Requirement.second << Requirement.first
1566           << SourceRange(Path.front().second, Path.back().second);
1567       }
1568       LastModuleImportLoc = ImportLoc;
1569       LastModuleImportResult = ModuleLoadResult();
1570       return ModuleLoadResult();
1571     }
1572 
1573     ModuleManager->makeModuleVisible(Module, Visibility, ImportLoc,
1574                                      /*Complain=*/true);
1575   }
1576 
1577   // Check for any configuration macros that have changed.
1578   clang::Module *TopModule = Module->getTopLevelModule();
1579   for (unsigned I = 0, N = TopModule->ConfigMacros.size(); I != N; ++I) {
1580     checkConfigMacro(getPreprocessor(), TopModule->ConfigMacros[I],
1581                      Module, ImportLoc);
1582   }
1583 
1584   // Determine whether we're in the #include buffer for a module. The #includes
1585   // in that buffer do not qualify as module imports; they're just an
1586   // implementation detail of us building the module.
1587   bool IsInModuleIncludes = !getLangOpts().CurrentModule.empty() &&
1588                             getSourceManager().getFileID(ImportLoc) ==
1589                                 getSourceManager().getMainFileID();
1590 
1591   // If this module import was due to an inclusion directive, create an
1592   // implicit import declaration to capture it in the AST.
1593   if (IsInclusionDirective && hasASTContext() && !IsInModuleIncludes) {
1594     TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
1595     ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
1596                                                      ImportLoc, Module,
1597                                                      Path.back().second);
1598     TU->addDecl(ImportD);
1599     if (Consumer)
1600       Consumer->HandleImplicitImportDecl(ImportD);
1601   }
1602 
1603   LastModuleImportLoc = ImportLoc;
1604   LastModuleImportResult = ModuleLoadResult(Module, false);
1605   return LastModuleImportResult;
1606 }
1607 
1608 void CompilerInstance::makeModuleVisible(Module *Mod,
1609                                          Module::NameVisibilityKind Visibility,
1610                                          SourceLocation ImportLoc,
1611                                          bool Complain){
1612   ModuleManager->makeModuleVisible(Mod, Visibility, ImportLoc, Complain);
1613 }
1614 
1615 GlobalModuleIndex *CompilerInstance::loadGlobalModuleIndex(
1616     SourceLocation TriggerLoc) {
1617   if (!ModuleManager)
1618     createModuleManager();
1619   // Can't do anything if we don't have the module manager.
1620   if (!ModuleManager)
1621     return nullptr;
1622   // Get an existing global index.  This loads it if not already
1623   // loaded.
1624   ModuleManager->loadGlobalIndex();
1625   GlobalModuleIndex *GlobalIndex = ModuleManager->getGlobalIndex();
1626   // If the global index doesn't exist, create it.
1627   if (!GlobalIndex && shouldBuildGlobalModuleIndex() && hasFileManager() &&
1628       hasPreprocessor()) {
1629     llvm::sys::fs::create_directories(
1630       getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
1631     GlobalModuleIndex::writeIndex(
1632       getFileManager(),
1633       getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
1634     ModuleManager->resetForReload();
1635     ModuleManager->loadGlobalIndex();
1636     GlobalIndex = ModuleManager->getGlobalIndex();
1637   }
1638   // For finding modules needing to be imported for fixit messages,
1639   // we need to make the global index cover all modules, so we do that here.
1640   if (!HaveFullGlobalModuleIndex && GlobalIndex && !buildingModule()) {
1641     ModuleMap &MMap = getPreprocessor().getHeaderSearchInfo().getModuleMap();
1642     bool RecreateIndex = false;
1643     for (ModuleMap::module_iterator I = MMap.module_begin(),
1644         E = MMap.module_end(); I != E; ++I) {
1645       Module *TheModule = I->second;
1646       const FileEntry *Entry = TheModule->getASTFile();
1647       if (!Entry) {
1648         SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 2> Path;
1649         Path.push_back(std::make_pair(
1650 				  getPreprocessor().getIdentifierInfo(TheModule->Name), TriggerLoc));
1651         std::reverse(Path.begin(), Path.end());
1652 		    // Load a module as hidden.  This also adds it to the global index.
1653         loadModule(TheModule->DefinitionLoc, Path,
1654                                              Module::Hidden, false);
1655         RecreateIndex = true;
1656       }
1657     }
1658     if (RecreateIndex) {
1659       GlobalModuleIndex::writeIndex(
1660         getFileManager(),
1661         getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
1662       ModuleManager->resetForReload();
1663       ModuleManager->loadGlobalIndex();
1664       GlobalIndex = ModuleManager->getGlobalIndex();
1665     }
1666     HaveFullGlobalModuleIndex = true;
1667   }
1668   return GlobalIndex;
1669 }
1670 
1671 // Check global module index for missing imports.
1672 bool
1673 CompilerInstance::lookupMissingImports(StringRef Name,
1674                                        SourceLocation TriggerLoc) {
1675   // Look for the symbol in non-imported modules, but only if an error
1676   // actually occurred.
1677   if (!buildingModule()) {
1678     // Load global module index, or retrieve a previously loaded one.
1679     GlobalModuleIndex *GlobalIndex = loadGlobalModuleIndex(
1680       TriggerLoc);
1681 
1682     // Only if we have a global index.
1683     if (GlobalIndex) {
1684       GlobalModuleIndex::HitSet FoundModules;
1685 
1686       // Find the modules that reference the identifier.
1687       // Note that this only finds top-level modules.
1688       // We'll let diagnoseTypo find the actual declaration module.
1689       if (GlobalIndex->lookupIdentifier(Name, FoundModules))
1690         return true;
1691     }
1692   }
1693 
1694   return false;
1695 }
1696 void CompilerInstance::resetAndLeakSema() { BuryPointer(takeSema()); }
1697