CompilerInstance.cpp revision 1f6b2b5c82b2d2d3935b0db76352a04e9877b73f 
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/Sema/Sema.h"
12#include "clang/AST/ASTConsumer.h"
13#include "clang/AST/ASTContext.h"
14#include "clang/AST/Decl.h"
15#include "clang/Basic/Diagnostic.h"
16#include "clang/Basic/FileManager.h"
17#include "clang/Basic/SourceManager.h"
18#include "clang/Basic/TargetInfo.h"
19#include "clang/Basic/Version.h"
20#include "clang/Lex/HeaderSearch.h"
21#include "clang/Lex/Preprocessor.h"
22#include "clang/Lex/PTHManager.h"
23#include "clang/Frontend/ChainedDiagnosticConsumer.h"
24#include "clang/Frontend/FrontendAction.h"
25#include "clang/Frontend/FrontendActions.h"
26#include "clang/Frontend/FrontendDiagnostic.h"
27#include "clang/Frontend/LogDiagnosticPrinter.h"
28#include "clang/Frontend/SerializedDiagnosticPrinter.h"
29#include "clang/Frontend/TextDiagnosticPrinter.h"
30#include "clang/Frontend/VerifyDiagnosticConsumer.h"
31#include "clang/Frontend/Utils.h"
32#include "clang/Serialization/ASTReader.h"
33#include "clang/Sema/CodeCompleteConsumer.h"
34#include "llvm/Support/FileSystem.h"
35#include "llvm/Support/MemoryBuffer.h"
36#include "llvm/Support/raw_ostream.h"
37#include "llvm/ADT/Statistic.h"
38#include "llvm/Support/Timer.h"
39#include "llvm/Support/Host.h"
40#include "llvm/Support/Path.h"
41#include "llvm/Support/Program.h"
42#include "llvm/Support/Signals.h"
43#include "llvm/Support/system_error.h"
44#include "llvm/Support/CrashRecoveryContext.h"
45#include "llvm/Config/config.h"
46
47// Support for FileLockManager
48#include <fstream>
49#include <sys/types.h>
50#include <sys/stat.h>
51
52#if LLVM_ON_WIN32
53#include <windows.h>
54#endif
55#if LLVM_ON_UNIX
56#include <unistd.h>
57#endif
58
59using namespace clang;
60
61CompilerInstance::CompilerInstance()
62  : Invocation(new CompilerInvocation()), ModuleManager(0) {
63}
64
65CompilerInstance::~CompilerInstance() {
66}
67
68void CompilerInstance::setInvocation(CompilerInvocation *Value) {
69  Invocation = Value;
70}
71
72void CompilerInstance::setDiagnostics(DiagnosticsEngine *Value) {
73  Diagnostics = Value;
74}
75
76void CompilerInstance::setTarget(TargetInfo *Value) {
77  Target = Value;
78}
79
80void CompilerInstance::setFileManager(FileManager *Value) {
81  FileMgr = Value;
82}
83
84void CompilerInstance::setSourceManager(SourceManager *Value) {
85  SourceMgr = Value;
86}
87
88void CompilerInstance::setPreprocessor(Preprocessor *Value) { PP = Value; }
89
90void CompilerInstance::setASTContext(ASTContext *Value) { Context = Value; }
91
92void CompilerInstance::setSema(Sema *S) {
93  TheSema.reset(S);
94}
95
96void CompilerInstance::setASTConsumer(ASTConsumer *Value) {
97  Consumer.reset(Value);
98}
99
100void CompilerInstance::setCodeCompletionConsumer(CodeCompleteConsumer *Value) {
101  CompletionConsumer.reset(Value);
102}
103
104// Diagnostics
105static void SetUpBuildDumpLog(const DiagnosticOptions &DiagOpts,
106                              unsigned argc, const char* const *argv,
107                              DiagnosticsEngine &Diags) {
108  std::string ErrorInfo;
109  llvm::OwningPtr<raw_ostream> OS(
110    new llvm::raw_fd_ostream(DiagOpts.DumpBuildInformation.c_str(), ErrorInfo));
111  if (!ErrorInfo.empty()) {
112    Diags.Report(diag::err_fe_unable_to_open_logfile)
113                 << DiagOpts.DumpBuildInformation << ErrorInfo;
114    return;
115  }
116
117  (*OS) << "clang -cc1 command line arguments: ";
118  for (unsigned i = 0; i != argc; ++i)
119    (*OS) << argv[i] << ' ';
120  (*OS) << '\n';
121
122  // Chain in a diagnostic client which will log the diagnostics.
123  DiagnosticConsumer *Logger =
124    new TextDiagnosticPrinter(*OS.take(), DiagOpts, /*OwnsOutputStream=*/true);
125  Diags.setClient(new ChainedDiagnosticConsumer(Diags.takeClient(), Logger));
126}
127
128static void SetUpDiagnosticLog(const DiagnosticOptions &DiagOpts,
129                               const CodeGenOptions *CodeGenOpts,
130                               DiagnosticsEngine &Diags) {
131  std::string ErrorInfo;
132  bool OwnsStream = false;
133  raw_ostream *OS = &llvm::errs();
134  if (DiagOpts.DiagnosticLogFile != "-") {
135    // Create the output stream.
136    llvm::raw_fd_ostream *FileOS(
137      new llvm::raw_fd_ostream(DiagOpts.DiagnosticLogFile.c_str(),
138                               ErrorInfo, llvm::raw_fd_ostream::F_Append));
139    if (!ErrorInfo.empty()) {
140      Diags.Report(diag::warn_fe_cc_log_diagnostics_failure)
141        << DiagOpts.DumpBuildInformation << ErrorInfo;
142    } else {
143      FileOS->SetUnbuffered();
144      FileOS->SetUseAtomicWrites(true);
145      OS = FileOS;
146      OwnsStream = true;
147    }
148  }
149
150  // Chain in the diagnostic client which will log the diagnostics.
151  LogDiagnosticPrinter *Logger = new LogDiagnosticPrinter(*OS, DiagOpts,
152                                                          OwnsStream);
153  if (CodeGenOpts)
154    Logger->setDwarfDebugFlags(CodeGenOpts->DwarfDebugFlags);
155  Diags.setClient(new ChainedDiagnosticConsumer(Diags.takeClient(), Logger));
156}
157
158static void SetupSerializedDiagnostics(const DiagnosticOptions &DiagOpts,
159                                       DiagnosticsEngine &Diags,
160                                       StringRef OutputFile) {
161  std::string ErrorInfo;
162  llvm::OwningPtr<llvm::raw_fd_ostream> OS;
163  OS.reset(new llvm::raw_fd_ostream(OutputFile.str().c_str(), ErrorInfo,
164                                    llvm::raw_fd_ostream::F_Binary));
165
166  if (!ErrorInfo.empty()) {
167    Diags.Report(diag::warn_fe_serialized_diag_failure)
168      << OutputFile << ErrorInfo;
169    return;
170  }
171
172  DiagnosticConsumer *SerializedConsumer =
173    clang::serialized_diags::create(OS.take(), DiagOpts);
174
175
176  Diags.setClient(new ChainedDiagnosticConsumer(Diags.takeClient(),
177                                                SerializedConsumer));
178}
179
180void CompilerInstance::createDiagnostics(int Argc, const char* const *Argv,
181                                         DiagnosticConsumer *Client,
182                                         bool ShouldOwnClient,
183                                         bool ShouldCloneClient) {
184  Diagnostics = createDiagnostics(getDiagnosticOpts(), Argc, Argv, Client,
185                                  ShouldOwnClient, ShouldCloneClient,
186                                  &getCodeGenOpts());
187}
188
189llvm::IntrusiveRefCntPtr<DiagnosticsEngine>
190CompilerInstance::createDiagnostics(const DiagnosticOptions &Opts,
191                                    int Argc, const char* const *Argv,
192                                    DiagnosticConsumer *Client,
193                                    bool ShouldOwnClient,
194                                    bool ShouldCloneClient,
195                                    const CodeGenOptions *CodeGenOpts) {
196  llvm::IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
197  llvm::IntrusiveRefCntPtr<DiagnosticsEngine>
198      Diags(new DiagnosticsEngine(DiagID));
199
200  // Create the diagnostic client for reporting errors or for
201  // implementing -verify.
202  if (Client) {
203    if (ShouldCloneClient)
204      Diags->setClient(Client->clone(*Diags), ShouldOwnClient);
205    else
206      Diags->setClient(Client, ShouldOwnClient);
207  } else
208    Diags->setClient(new TextDiagnosticPrinter(llvm::errs(), Opts));
209
210  // Chain in -verify checker, if requested.
211  if (Opts.VerifyDiagnostics)
212    Diags->setClient(new VerifyDiagnosticConsumer(*Diags));
213
214  // Chain in -diagnostic-log-file dumper, if requested.
215  if (!Opts.DiagnosticLogFile.empty())
216    SetUpDiagnosticLog(Opts, CodeGenOpts, *Diags);
217
218  if (!Opts.DumpBuildInformation.empty())
219    SetUpBuildDumpLog(Opts, Argc, Argv, *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
233void CompilerInstance::createFileManager() {
234  FileMgr = new FileManager(getFileSystemOpts());
235}
236
237// Source Manager
238
239void CompilerInstance::createSourceManager(FileManager &FileMgr) {
240  SourceMgr = new SourceManager(getDiagnostics(), FileMgr);
241}
242
243// Preprocessor
244
245void CompilerInstance::createPreprocessor() {
246  const PreprocessorOptions &PPOpts = getPreprocessorOpts();
247
248  // Create a PTH manager if we are using some form of a token cache.
249  PTHManager *PTHMgr = 0;
250  if (!PPOpts.TokenCache.empty())
251    PTHMgr = PTHManager::Create(PPOpts.TokenCache, getDiagnostics());
252
253  // Create the Preprocessor.
254  HeaderSearch *HeaderInfo = new HeaderSearch(getFileManager(),
255                                              getDiagnostics(),
256                                              getLangOpts());
257  PP = new Preprocessor(getDiagnostics(), getLangOpts(), &getTarget(),
258                        getSourceManager(), *HeaderInfo, *this, PTHMgr,
259                        /*OwnsHeaderSearch=*/true);
260
261  // Note that this is different then passing PTHMgr to Preprocessor's ctor.
262  // That argument is used as the IdentifierInfoLookup argument to
263  // IdentifierTable's ctor.
264  if (PTHMgr) {
265    PTHMgr->setPreprocessor(&*PP);
266    PP->setPTHManager(PTHMgr);
267  }
268
269  if (PPOpts.DetailedRecord)
270    PP->createPreprocessingRecord(
271                                  PPOpts.DetailedRecordIncludesNestedMacroExpansions);
272
273  InitializePreprocessor(*PP, PPOpts, getHeaderSearchOpts(), getFrontendOpts());
274
275  // Set up the module path, including the hash for the
276  // module-creation options.
277  llvm::SmallString<256> SpecificModuleCache(
278                           getHeaderSearchOpts().ModuleCachePath);
279  if (!getHeaderSearchOpts().DisableModuleHash)
280    llvm::sys::path::append(SpecificModuleCache,
281                            getInvocation().getModuleHash());
282  PP->getHeaderSearchInfo().setModuleCachePath(SpecificModuleCache);
283
284  // Handle generating dependencies, if requested.
285  const DependencyOutputOptions &DepOpts = getDependencyOutputOpts();
286  if (!DepOpts.OutputFile.empty())
287    AttachDependencyFileGen(*PP, DepOpts);
288
289  // Handle generating header include information, if requested.
290  if (DepOpts.ShowHeaderIncludes)
291    AttachHeaderIncludeGen(*PP);
292  if (!DepOpts.HeaderIncludeOutputFile.empty()) {
293    StringRef OutputPath = DepOpts.HeaderIncludeOutputFile;
294    if (OutputPath == "-")
295      OutputPath = "";
296    AttachHeaderIncludeGen(*PP, /*ShowAllHeaders=*/true, OutputPath,
297                           /*ShowDepth=*/false);
298  }
299}
300
301// ASTContext
302
303void CompilerInstance::createASTContext() {
304  Preprocessor &PP = getPreprocessor();
305  Context = new ASTContext(getLangOpts(), PP.getSourceManager(),
306                           &getTarget(), PP.getIdentifierTable(),
307                           PP.getSelectorTable(), PP.getBuiltinInfo(),
308                           /*size_reserve=*/ 0);
309}
310
311// ExternalASTSource
312
313void CompilerInstance::createPCHExternalASTSource(StringRef Path,
314                                                  bool DisablePCHValidation,
315                                                  bool DisableStatCache,
316                                                 void *DeserializationListener){
317  llvm::OwningPtr<ExternalASTSource> Source;
318  bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
319  Source.reset(createPCHExternalASTSource(Path, getHeaderSearchOpts().Sysroot,
320                                          DisablePCHValidation,
321                                          DisableStatCache,
322                                          getPreprocessor(), getASTContext(),
323                                          DeserializationListener,
324                                          Preamble));
325  ModuleManager = static_cast<ASTReader*>(Source.get());
326  getASTContext().setExternalSource(Source);
327}
328
329ExternalASTSource *
330CompilerInstance::createPCHExternalASTSource(StringRef Path,
331                                             const std::string &Sysroot,
332                                             bool DisablePCHValidation,
333                                             bool DisableStatCache,
334                                             Preprocessor &PP,
335                                             ASTContext &Context,
336                                             void *DeserializationListener,
337                                             bool Preamble) {
338  llvm::OwningPtr<ASTReader> Reader;
339  Reader.reset(new ASTReader(PP, Context,
340                             Sysroot.empty() ? "" : Sysroot.c_str(),
341                             DisablePCHValidation, DisableStatCache));
342
343  Reader->setDeserializationListener(
344            static_cast<ASTDeserializationListener *>(DeserializationListener));
345  switch (Reader->ReadAST(Path,
346                          Preamble ? serialization::MK_Preamble
347                                   : serialization::MK_PCH)) {
348  case ASTReader::Success:
349    // Set the predefines buffer as suggested by the PCH reader. Typically, the
350    // predefines buffer will be empty.
351    PP.setPredefines(Reader->getSuggestedPredefines());
352    return Reader.take();
353
354  case ASTReader::Failure:
355    // Unrecoverable failure: don't even try to process the input file.
356    break;
357
358  case ASTReader::IgnorePCH:
359    // No suitable PCH file could be found. Return an error.
360    break;
361  }
362
363  return 0;
364}
365
366// Code Completion
367
368static bool EnableCodeCompletion(Preprocessor &PP,
369                                 const std::string &Filename,
370                                 unsigned Line,
371                                 unsigned Column) {
372  // Tell the source manager to chop off the given file at a specific
373  // line and column.
374  const FileEntry *Entry = PP.getFileManager().getFile(Filename);
375  if (!Entry) {
376    PP.getDiagnostics().Report(diag::err_fe_invalid_code_complete_file)
377      << Filename;
378    return true;
379  }
380
381  // Truncate the named file at the given line/column.
382  PP.SetCodeCompletionPoint(Entry, Line, Column);
383  return false;
384}
385
386void CompilerInstance::createCodeCompletionConsumer() {
387  const ParsedSourceLocation &Loc = getFrontendOpts().CodeCompletionAt;
388  if (!CompletionConsumer) {
389    CompletionConsumer.reset(
390      createCodeCompletionConsumer(getPreprocessor(),
391                                   Loc.FileName, Loc.Line, Loc.Column,
392                                   getFrontendOpts().ShowMacrosInCodeCompletion,
393                             getFrontendOpts().ShowCodePatternsInCodeCompletion,
394                           getFrontendOpts().ShowGlobalSymbolsInCodeCompletion,
395                                   llvm::outs()));
396    if (!CompletionConsumer)
397      return;
398  } else if (EnableCodeCompletion(getPreprocessor(), Loc.FileName,
399                                  Loc.Line, Loc.Column)) {
400    CompletionConsumer.reset();
401    return;
402  }
403
404  if (CompletionConsumer->isOutputBinary() &&
405      llvm::sys::Program::ChangeStdoutToBinary()) {
406    getPreprocessor().getDiagnostics().Report(diag::err_fe_stdout_binary);
407    CompletionConsumer.reset();
408  }
409}
410
411void CompilerInstance::createFrontendTimer() {
412  FrontendTimer.reset(new llvm::Timer("Clang front-end timer"));
413}
414
415CodeCompleteConsumer *
416CompilerInstance::createCodeCompletionConsumer(Preprocessor &PP,
417                                               const std::string &Filename,
418                                               unsigned Line,
419                                               unsigned Column,
420                                               bool ShowMacros,
421                                               bool ShowCodePatterns,
422                                               bool ShowGlobals,
423                                               raw_ostream &OS) {
424  if (EnableCodeCompletion(PP, Filename, Line, Column))
425    return 0;
426
427  // Set up the creation routine for code-completion.
428  return new PrintingCodeCompleteConsumer(ShowMacros, ShowCodePatterns,
429                                          ShowGlobals, OS);
430}
431
432void CompilerInstance::createSema(TranslationUnitKind TUKind,
433                                  CodeCompleteConsumer *CompletionConsumer) {
434  TheSema.reset(new Sema(getPreprocessor(), getASTContext(), getASTConsumer(),
435                         TUKind, CompletionConsumer));
436}
437
438// Output Files
439
440void CompilerInstance::addOutputFile(const OutputFile &OutFile) {
441  assert(OutFile.OS && "Attempt to add empty stream to output list!");
442  OutputFiles.push_back(OutFile);
443}
444
445void CompilerInstance::clearOutputFiles(bool EraseFiles) {
446  for (std::list<OutputFile>::iterator
447         it = OutputFiles.begin(), ie = OutputFiles.end(); it != ie; ++it) {
448    delete it->OS;
449    if (!it->TempFilename.empty()) {
450      if (EraseFiles) {
451        bool existed;
452        llvm::sys::fs::remove(it->TempFilename, existed);
453      } else {
454        llvm::SmallString<128> NewOutFile(it->Filename);
455
456        // If '-working-directory' was passed, the output filename should be
457        // relative to that.
458        FileMgr->FixupRelativePath(NewOutFile);
459        if (llvm::error_code ec = llvm::sys::fs::rename(it->TempFilename,
460                                                        NewOutFile.str())) {
461          getDiagnostics().Report(diag::err_fe_unable_to_rename_temp)
462            << it->TempFilename << it->Filename << ec.message();
463
464          bool existed;
465          llvm::sys::fs::remove(it->TempFilename, existed);
466        }
467      }
468    } else if (!it->Filename.empty() && EraseFiles)
469      llvm::sys::Path(it->Filename).eraseFromDisk();
470
471  }
472  OutputFiles.clear();
473}
474
475llvm::raw_fd_ostream *
476CompilerInstance::createDefaultOutputFile(bool Binary,
477                                          StringRef InFile,
478                                          StringRef Extension) {
479  return createOutputFile(getFrontendOpts().OutputFile, Binary,
480                          /*RemoveFileOnSignal=*/true, InFile, Extension);
481}
482
483llvm::raw_fd_ostream *
484CompilerInstance::createOutputFile(StringRef OutputPath,
485                                   bool Binary, bool RemoveFileOnSignal,
486                                   StringRef InFile,
487                                   StringRef Extension,
488                                   bool UseTemporary) {
489  std::string Error, OutputPathName, TempPathName;
490  llvm::raw_fd_ostream *OS = createOutputFile(OutputPath, Error, Binary,
491                                              RemoveFileOnSignal,
492                                              InFile, Extension,
493                                              UseTemporary,
494                                              &OutputPathName,
495                                              &TempPathName);
496  if (!OS) {
497    getDiagnostics().Report(diag::err_fe_unable_to_open_output)
498      << OutputPath << Error;
499    return 0;
500  }
501
502  // Add the output file -- but don't try to remove "-", since this means we are
503  // using stdin.
504  addOutputFile(OutputFile((OutputPathName != "-") ? OutputPathName : "",
505                TempPathName, OS));
506
507  return OS;
508}
509
510llvm::raw_fd_ostream *
511CompilerInstance::createOutputFile(StringRef OutputPath,
512                                   std::string &Error,
513                                   bool Binary,
514                                   bool RemoveFileOnSignal,
515                                   StringRef InFile,
516                                   StringRef Extension,
517                                   bool UseTemporary,
518                                   std::string *ResultPathName,
519                                   std::string *TempPathName) {
520  std::string OutFile, TempFile;
521  if (!OutputPath.empty()) {
522    OutFile = OutputPath;
523  } else if (InFile == "-") {
524    OutFile = "-";
525  } else if (!Extension.empty()) {
526    llvm::sys::Path Path(InFile);
527    Path.eraseSuffix();
528    Path.appendSuffix(Extension);
529    OutFile = Path.str();
530  } else {
531    OutFile = "-";
532  }
533
534  llvm::OwningPtr<llvm::raw_fd_ostream> OS;
535  std::string OSFile;
536
537  if (UseTemporary && OutFile != "-") {
538    llvm::sys::Path OutPath(OutFile);
539    // Only create the temporary if we can actually write to OutPath, otherwise
540    // we want to fail early.
541    bool Exists;
542    if ((llvm::sys::fs::exists(OutPath.str(), Exists) || !Exists) ||
543        (OutPath.isRegularFile() && OutPath.canWrite())) {
544      // Create a temporary file.
545      llvm::SmallString<128> TempPath;
546      TempPath = OutFile;
547      TempPath += "-%%%%%%%%";
548      int fd;
549      if (llvm::sys::fs::unique_file(TempPath.str(), fd, TempPath,
550                               /*makeAbsolute=*/false) == llvm::errc::success) {
551        OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
552        OSFile = TempFile = TempPath.str();
553      }
554    }
555  }
556
557  if (!OS) {
558    OSFile = OutFile;
559    OS.reset(
560      new llvm::raw_fd_ostream(OSFile.c_str(), Error,
561                               (Binary ? llvm::raw_fd_ostream::F_Binary : 0)));
562    if (!Error.empty())
563      return 0;
564  }
565
566  // Make sure the out stream file gets removed if we crash.
567  if (RemoveFileOnSignal)
568    llvm::sys::RemoveFileOnSignal(llvm::sys::Path(OSFile));
569
570  if (ResultPathName)
571    *ResultPathName = OutFile;
572  if (TempPathName)
573    *TempPathName = TempFile;
574
575  return OS.take();
576}
577
578// Initialization Utilities
579
580bool CompilerInstance::InitializeSourceManager(StringRef InputFile) {
581  return InitializeSourceManager(InputFile, getDiagnostics(), getFileManager(),
582                                 getSourceManager(), getFrontendOpts());
583}
584
585bool CompilerInstance::InitializeSourceManager(StringRef InputFile,
586                                               DiagnosticsEngine &Diags,
587                                               FileManager &FileMgr,
588                                               SourceManager &SourceMgr,
589                                               const FrontendOptions &Opts) {
590  // Figure out where to get and map in the main file.
591  if (InputFile != "-") {
592    const FileEntry *File = FileMgr.getFile(InputFile);
593    if (!File) {
594      Diags.Report(diag::err_fe_error_reading) << InputFile;
595      return false;
596    }
597    SourceMgr.createMainFileID(File);
598  } else {
599    llvm::OwningPtr<llvm::MemoryBuffer> SB;
600    if (llvm::MemoryBuffer::getSTDIN(SB)) {
601      // FIXME: Give ec.message() in this diag.
602      Diags.Report(diag::err_fe_error_reading_stdin);
603      return false;
604    }
605    const FileEntry *File = FileMgr.getVirtualFile(SB->getBufferIdentifier(),
606                                                   SB->getBufferSize(), 0);
607    SourceMgr.createMainFileID(File);
608    SourceMgr.overrideFileContents(File, SB.take());
609  }
610
611  assert(!SourceMgr.getMainFileID().isInvalid() &&
612         "Couldn't establish MainFileID!");
613  return true;
614}
615
616// High-Level Operations
617
618bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
619  assert(hasDiagnostics() && "Diagnostics engine is not initialized!");
620  assert(!getFrontendOpts().ShowHelp && "Client must handle '-help'!");
621  assert(!getFrontendOpts().ShowVersion && "Client must handle '-version'!");
622
623  // FIXME: Take this as an argument, once all the APIs we used have moved to
624  // taking it as an input instead of hard-coding llvm::errs.
625  raw_ostream &OS = llvm::errs();
626
627  // Create the target instance.
628  setTarget(TargetInfo::CreateTargetInfo(getDiagnostics(), getTargetOpts()));
629  if (!hasTarget())
630    return false;
631
632  // Inform the target of the language options.
633  //
634  // FIXME: We shouldn't need to do this, the target should be immutable once
635  // created. This complexity should be lifted elsewhere.
636  getTarget().setForcedLangOptions(getLangOpts());
637
638  // Validate/process some options.
639  if (getHeaderSearchOpts().Verbose)
640    OS << "clang -cc1 version " CLANG_VERSION_STRING
641       << " based upon " << PACKAGE_STRING
642       << " default target " << llvm::sys::getDefaultTargetTriple() << "\n";
643
644  if (getFrontendOpts().ShowTimers)
645    createFrontendTimer();
646
647  if (getFrontendOpts().ShowStats)
648    llvm::EnableStatistics();
649
650  for (unsigned i = 0, e = getFrontendOpts().Inputs.size(); i != e; ++i) {
651    // Reset the ID tables if we are reusing the SourceManager.
652    if (hasSourceManager())
653      getSourceManager().clearIDTables();
654
655    if (Act.BeginSourceFile(*this, getFrontendOpts().Inputs[i])) {
656      Act.Execute();
657      Act.EndSourceFile();
658    }
659  }
660
661  // Notify the diagnostic client that all files were processed.
662  getDiagnostics().getClient()->finish();
663
664  if (getDiagnosticOpts().ShowCarets) {
665    // We can have multiple diagnostics sharing one diagnostic client.
666    // Get the total number of warnings/errors from the client.
667    unsigned NumWarnings = getDiagnostics().getClient()->getNumWarnings();
668    unsigned NumErrors = getDiagnostics().getClient()->getNumErrors();
669
670    if (NumWarnings)
671      OS << NumWarnings << " warning" << (NumWarnings == 1 ? "" : "s");
672    if (NumWarnings && NumErrors)
673      OS << " and ";
674    if (NumErrors)
675      OS << NumErrors << " error" << (NumErrors == 1 ? "" : "s");
676    if (NumWarnings || NumErrors)
677      OS << " generated.\n";
678  }
679
680  if (getFrontendOpts().ShowStats && hasFileManager()) {
681    getFileManager().PrintStats();
682    OS << "\n";
683  }
684
685  return !getDiagnostics().getClient()->getNumErrors();
686}
687
688/// \brief Determine the appropriate source input kind based on language
689/// options.
690static InputKind getSourceInputKindFromOptions(const LangOptions &LangOpts) {
691  if (LangOpts.OpenCL)
692    return IK_OpenCL;
693  if (LangOpts.CUDA)
694    return IK_CUDA;
695  if (LangOpts.ObjC1)
696    return LangOpts.CPlusPlus? IK_ObjCXX : IK_ObjC;
697  return LangOpts.CPlusPlus? IK_CXX : IK_C;
698}
699
700namespace {
701  struct CompileModuleMapData {
702    CompilerInstance &Instance;
703    GenerateModuleAction &CreateModuleAction;
704  };
705}
706
707/// \brief Helper function that executes the module-generating action under
708/// a crash recovery context.
709static void doCompileMapModule(void *UserData) {
710  CompileModuleMapData &Data
711    = *reinterpret_cast<CompileModuleMapData *>(UserData);
712  Data.Instance.ExecuteAction(Data.CreateModuleAction);
713}
714
715namespace {
716  /// \brief Class that manages the creation of a lock file to aid
717  /// implicit coordination between different processes.
718  ///
719  /// The implicit coordination works by creating a ".lock" file alongside
720  /// the file that we're coordinating for, using the atomicity of the file
721  /// system to ensure that only a single process can create that ".lock" file.
722  /// When the lock file is removed, the owning process has finished the
723  /// operation.
724  class LockFileManager {
725  public:
726    /// \brief Describes the state of a lock file.
727    enum LockFileState {
728      /// \brief The lock file has been created and is owned by this instance
729      /// of the object.
730      LFS_Owned,
731      /// \brief The lock file already exists and is owned by some other
732      /// instance.
733      LFS_Shared,
734      /// \brief An error occurred while trying to create or find the lock
735      /// file.
736      LFS_Error
737    };
738
739  private:
740    llvm::SmallString<128> LockFileName;
741    llvm::SmallString<128> UniqueLockFileName;
742
743    llvm::Optional<std::pair<std::string, int> > Owner;
744    llvm::Optional<llvm::error_code> Error;
745
746    LockFileManager(const LockFileManager &);
747    LockFileManager &operator=(const LockFileManager &);
748
749    static llvm::Optional<std::pair<std::string, int> >
750    readLockFile(StringRef LockFileName);
751
752    static bool processStillExecuting(StringRef Hostname, int PID);
753
754  public:
755
756    LockFileManager(StringRef FileName);
757    ~LockFileManager();
758
759    /// \brief Determine the state of the lock file.
760    LockFileState getState() const;
761
762    operator LockFileState() const { return getState(); }
763
764    /// \brief For a shared lock, wait until the owner releases the lock.
765    void waitForUnlock();
766  };
767}
768
769/// \brief Attempt to read the lock file with the given name, if it exists.
770///
771/// \param LockFileName The name of the lock file to read.
772///
773/// \returns The process ID of the process that owns this lock file
774llvm::Optional<std::pair<std::string, int> >
775LockFileManager::readLockFile(StringRef LockFileName) {
776  // Check whether the lock file exists. If not, clearly there's nothing
777  // to read, so we just return.
778  bool Exists = false;
779  if (llvm::sys::fs::exists(LockFileName, Exists) || !Exists)
780    return llvm::Optional<std::pair<std::string, int> >();
781
782  // Read the owning host and PID out of the lock file. If it appears that the
783  // owning process is dead, the lock file is invalid.
784  int PID = 0;
785  std::string Hostname;
786  std::ifstream Input(LockFileName.str().c_str());
787  if (Input >> Hostname >> PID && PID > 0 &&
788      processStillExecuting(Hostname, PID))
789    return std::make_pair(Hostname, PID);
790
791  // Delete the lock file. It's invalid anyway.
792  bool Existed;
793  llvm::sys::fs::remove(LockFileName, Existed);
794  return llvm::Optional<std::pair<std::string, int> >();
795}
796
797bool LockFileManager::processStillExecuting(StringRef Hostname, int PID) {
798#if LLVM_ON_UNIX
799  char MyHostname[256];
800  MyHostname[255] = 0;
801  MyHostname[0] = 0;
802  gethostname(MyHostname, 255);
803  // Check whether the process is dead. If so, we're done.
804  if (MyHostname == Hostname && getsid(PID) == -1 && errno == ESRCH)
805    return false;
806#endif
807
808  return true;
809}
810
811LockFileManager::LockFileManager(StringRef FileName)
812{
813  LockFileName = FileName;
814  LockFileName += ".lock";
815
816  // If the lock file already exists, don't bother to try to create our own
817  // lock file; it won't work anyway. Just figure out who owns this lock file.
818  if ((Owner = readLockFile(LockFileName)))
819    return;
820
821  // Create a lock file that is unique to this instance.
822  UniqueLockFileName = LockFileName;
823  UniqueLockFileName += "-%%%%%%%%";
824  int UniqueLockFileID;
825  if (llvm::error_code EC
826        = llvm::sys::fs::unique_file(UniqueLockFileName.str(),
827                                     UniqueLockFileID,
828                                     UniqueLockFileName,
829                                     /*makeAbsolute=*/false)) {
830    Error = EC;
831    return;
832  }
833
834  // Write our process ID to our unique lock file.
835  {
836    llvm::raw_fd_ostream Out(UniqueLockFileID, /*shouldClose=*/true);
837
838#if LLVM_ON_UNIX
839    // FIXME: move getpid() call into LLVM
840    char hostname[256];
841    hostname[255] = 0;
842    hostname[0] = 0;
843    gethostname(hostname, 255);
844    Out << hostname << ' ' << getpid();
845#else
846    Out << "localhost 1";
847#endif
848    Out.close();
849
850    if (Out.has_error()) {
851      // We failed to write out PID, so make up an excuse, remove the
852      // unique lock file, and fail.
853      Error = llvm::make_error_code(llvm::errc::no_space_on_device);
854      bool Existed;
855      llvm::sys::fs::remove(UniqueLockFileName.c_str(), Existed);
856      return;
857    }
858  }
859
860  // Create a hard link from the lock file name. If this succeeds, we're done.
861  llvm::error_code EC
862    = llvm::sys::fs::create_hard_link(UniqueLockFileName.str(),
863                                      LockFileName.str());
864  if (EC == llvm::errc::success)
865    return;
866
867  // Creating the hard link failed.
868
869#ifdef LLVM_ON_UNIX
870  // The creation of the hard link may appear to fail, but if stat'ing the
871  // unique file returns a link count of 2, then we can still declare success.
872  struct stat StatBuf;
873  if (stat(UniqueLockFileName.c_str(), &StatBuf) == 0 &&
874      StatBuf.st_nlink == 2)
875    return;
876#endif
877
878  // Someone else managed to create the lock file first. Wipe out our unique
879  // lock file (it's useless now) and read the process ID from the lock file.
880  bool Existed;
881  llvm::sys::fs::remove(UniqueLockFileName.str(), Existed);
882  if ((Owner = readLockFile(LockFileName)))
883    return;
884
885  // There is a lock file that nobody owns; try to clean it up and report
886  // an error.
887  llvm::sys::fs::remove(LockFileName.str(), Existed);
888  Error = EC;
889}
890
891LockFileManager::LockFileState LockFileManager::getState() const {
892  if (Owner)
893    return LFS_Shared;
894
895  if (Error)
896    return LFS_Error;
897
898  return LFS_Owned;
899}
900
901LockFileManager::~LockFileManager() {
902  if (getState() != LFS_Owned)
903    return;
904
905  // Since we own the lock, remove the lock file and our own unique lock file.
906  bool Existed;
907  llvm::sys::fs::remove(LockFileName.str(), Existed);
908  llvm::sys::fs::remove(UniqueLockFileName.str(), Existed);
909}
910
911void LockFileManager::waitForUnlock() {
912  if (getState() != LFS_Shared)
913    return;
914
915#if LLVM_ON_WIN32
916  unsigned long Interval = 1;
917#else
918  struct timespec Interval;
919  Interval.tv_sec = 0;
920  Interval.tv_nsec = 1000000;
921#endif
922  // Don't wait more than an hour for the file to appear.
923  const unsigned MaxSeconds = 3600;
924  do {
925    // Sleep for the designated interval, to allow the owning process time to
926    // finish up and
927    // FIXME: Should we hook in to system APIs to get a notification when the
928    // lock file is deleted?
929#if LLVM_ON_WIN32
930    Sleep(Interval);
931#else
932    nanosleep(&Interval, NULL);
933#endif
934    // If the file no longer exists, we're done.
935    bool Exists = false;
936    if (!llvm::sys::fs::exists(LockFileName.str(), Exists) && !Exists)
937      return;
938
939    if (!processStillExecuting((*Owner).first, (*Owner).second))
940      return;
941
942    // Exponentially increase the time we wait for the lock to be removed.
943#if LLVM_ON_WIN32
944    Interval *= 2;
945#else
946    Interval.tv_sec *= 2;
947    Interval.tv_nsec *= 2;
948    if (Interval.tv_nsec >= 1000000000) {
949      ++Interval.tv_sec;
950      Interval.tv_nsec -= 1000000000;
951    }
952#endif
953  } while (
954#if LLVM_ON_WIN32
955           Interval < MaxSeconds * 1000
956#else
957           Interval.tv_sec < (time_t)MaxSeconds
958#endif
959           );
960
961  // Give up.
962}
963
964/// \brief Compile a module file for the given module, using the options
965/// provided by the importing compiler instance.
966static void compileModule(CompilerInstance &ImportingInstance,
967                          Module *Module,
968                          StringRef ModuleFileName) {
969  LockFileManager Locked(ModuleFileName);
970  switch (Locked) {
971  case LockFileManager::LFS_Error:
972    return;
973
974  case LockFileManager::LFS_Owned:
975    // We're responsible for building the module ourselves. Do so below.
976    break;
977
978  case LockFileManager::LFS_Shared:
979    // Someone else is responsible for building the module. Wait for them to
980    // finish.
981    Locked.waitForUnlock();
982    break;
983  }
984
985  ModuleMap &ModMap
986    = ImportingInstance.getPreprocessor().getHeaderSearchInfo().getModuleMap();
987
988  // Construct a compiler invocation for creating this module.
989  llvm::IntrusiveRefCntPtr<CompilerInvocation> Invocation
990    (new CompilerInvocation(ImportingInstance.getInvocation()));
991
992  PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
993
994  // For any options that aren't intended to affect how a module is built,
995  // reset them to their default values.
996  Invocation->getLangOpts()->resetNonModularOptions();
997  PPOpts.resetNonModularOptions();
998
999  // Note the name of the module we're building.
1000  Invocation->getLangOpts()->CurrentModule = Module->getTopLevelModuleName();
1001
1002  // Note that this module is part of the module build path, so that we
1003  // can detect cycles in the module graph.
1004  PPOpts.ModuleBuildPath.push_back(Module->getTopLevelModuleName());
1005
1006  // If there is a module map file, build the module using the module map.
1007  // Set up the inputs/outputs so that we build the module from its umbrella
1008  // header.
1009  FrontendOptions &FrontendOpts = Invocation->getFrontendOpts();
1010  FrontendOpts.OutputFile = ModuleFileName.str();
1011  FrontendOpts.DisableFree = false;
1012  FrontendOpts.Inputs.clear();
1013  InputKind IK = getSourceInputKindFromOptions(*Invocation->getLangOpts());
1014
1015  // Get or create the module map that we'll use to build this module.
1016  llvm::SmallString<128> TempModuleMapFileName;
1017  if (const FileEntry *ModuleMapFile
1018                                  = ModMap.getContainingModuleMapFile(Module)) {
1019    // Use the module map where this module resides.
1020    FrontendOpts.Inputs.push_back(FrontendInputFile(ModuleMapFile->getName(),
1021                                                    IK));
1022  } else {
1023    // Create a temporary module map file.
1024    TempModuleMapFileName = Module->Name;
1025    TempModuleMapFileName += "-%%%%%%%%.map";
1026    int FD;
1027    if (llvm::sys::fs::unique_file(TempModuleMapFileName.str(), FD,
1028                                   TempModuleMapFileName,
1029                                   /*makeAbsolute=*/true)
1030          != llvm::errc::success) {
1031      ImportingInstance.getDiagnostics().Report(diag::err_module_map_temp_file)
1032        << TempModuleMapFileName;
1033      return;
1034    }
1035    // Print the module map to this file.
1036    llvm::raw_fd_ostream OS(FD, /*shouldClose=*/true);
1037    Module->print(OS);
1038    FrontendOpts.Inputs.push_back(
1039      FrontendInputFile(TempModuleMapFileName.str().str(), IK));
1040  }
1041
1042  // Don't free the remapped file buffers; they are owned by our caller.
1043  PPOpts.RetainRemappedFileBuffers = true;
1044
1045  Invocation->getDiagnosticOpts().VerifyDiagnostics = 0;
1046  assert(ImportingInstance.getInvocation().getModuleHash() ==
1047         Invocation->getModuleHash() && "Module hash mismatch!");
1048
1049  // Construct a compiler instance that will be used to actually create the
1050  // module.
1051  CompilerInstance Instance;
1052  Instance.setInvocation(&*Invocation);
1053  Instance.createDiagnostics(/*argc=*/0, /*argv=*/0,
1054                             &ImportingInstance.getDiagnosticClient(),
1055                             /*ShouldOwnClient=*/true,
1056                             /*ShouldCloneClient=*/true);
1057
1058  // Construct a module-generating action.
1059  GenerateModuleAction CreateModuleAction;
1060
1061  // Execute the action to actually build the module in-place. Use a separate
1062  // thread so that we get a stack large enough.
1063  const unsigned ThreadStackSize = 8 << 20;
1064  llvm::CrashRecoveryContext CRC;
1065  CompileModuleMapData Data = { Instance, CreateModuleAction };
1066  CRC.RunSafelyOnThread(&doCompileMapModule, &Data, ThreadStackSize);
1067
1068  // Delete the temporary module map file.
1069  // FIXME: Even though we're executing under crash protection, it would still
1070  // be nice to do this with RemoveFileOnSignal when we can. However, that
1071  // doesn't make sense for all clients, so clean this up manually.
1072  if (!TempModuleMapFileName.empty())
1073    llvm::sys::Path(TempModuleMapFileName).eraseFromDisk();
1074}
1075
1076Module *CompilerInstance::loadModule(SourceLocation ImportLoc,
1077                                     ModuleIdPath Path,
1078                                     Module::NameVisibilityKind Visibility,
1079                                     bool IsInclusionDirective) {
1080  // If we've already handled this import, just return the cached result.
1081  // This one-element cache is important to eliminate redundant diagnostics
1082  // when both the preprocessor and parser see the same import declaration.
1083  if (!ImportLoc.isInvalid() && LastModuleImportLoc == ImportLoc) {
1084    // Make the named module visible.
1085    if (LastModuleImportResult)
1086      ModuleManager->makeModuleVisible(LastModuleImportResult, Visibility);
1087    return LastModuleImportResult;
1088  }
1089
1090  // Determine what file we're searching from.
1091  SourceManager &SourceMgr = getSourceManager();
1092  SourceLocation ExpandedImportLoc = SourceMgr.getExpansionLoc(ImportLoc);
1093  const FileEntry *CurFile
1094    = SourceMgr.getFileEntryForID(SourceMgr.getFileID(ExpandedImportLoc));
1095  if (!CurFile)
1096    CurFile = SourceMgr.getFileEntryForID(SourceMgr.getMainFileID());
1097
1098  StringRef ModuleName = Path[0].first->getName();
1099  SourceLocation ModuleNameLoc = Path[0].second;
1100
1101  clang::Module *Module = 0;
1102  const FileEntry *ModuleFile = 0;
1103
1104  // If we don't already have information on this module, load the module now.
1105  llvm::DenseMap<const IdentifierInfo *, clang::Module *>::iterator Known
1106    = KnownModules.find(Path[0].first);
1107  if (Known != KnownModules.end()) {
1108    // Retrieve the cached top-level module.
1109    Module = Known->second;
1110  } else if (ModuleName == getLangOpts().CurrentModule) {
1111    // This is the module we're building.
1112    Module = PP->getHeaderSearchInfo().getModuleMap().findModule(ModuleName);
1113    Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1114  } else {
1115    // Search for a module with the given name.
1116    std::string ModuleFileName;
1117    ModuleFile
1118      = PP->getHeaderSearchInfo().lookupModule(ModuleName, Module,
1119                                               &ModuleFileName);
1120
1121    bool BuildingModule = false;
1122    if (!ModuleFile && Module) {
1123      // The module is not cached, but we have a module map from which we can
1124      // build the module.
1125
1126      // Check whether there is a cycle in the module graph.
1127      SmallVectorImpl<std::string> &ModuleBuildPath
1128        = getPreprocessorOpts().ModuleBuildPath;
1129      SmallVectorImpl<std::string>::iterator Pos
1130        = std::find(ModuleBuildPath.begin(), ModuleBuildPath.end(), ModuleName);
1131      if (Pos != ModuleBuildPath.end()) {
1132        llvm::SmallString<256> CyclePath;
1133        for (; Pos != ModuleBuildPath.end(); ++Pos) {
1134          CyclePath += *Pos;
1135          CyclePath += " -> ";
1136        }
1137        CyclePath += ModuleName;
1138
1139        getDiagnostics().Report(ModuleNameLoc, diag::err_module_cycle)
1140          << ModuleName << CyclePath;
1141        return 0;
1142      }
1143
1144      getDiagnostics().Report(ModuleNameLoc, diag::warn_module_build)
1145        << ModuleName;
1146      BuildingModule = true;
1147      compileModule(*this, Module, ModuleFileName);
1148      ModuleFile = FileMgr->getFile(ModuleFileName);
1149    }
1150
1151    if (!ModuleFile) {
1152      getDiagnostics().Report(ModuleNameLoc,
1153                              BuildingModule? diag::err_module_not_built
1154                                            : diag::err_module_not_found)
1155        << ModuleName
1156        << SourceRange(ImportLoc, ModuleNameLoc);
1157      return 0;
1158    }
1159
1160    // If we don't already have an ASTReader, create one now.
1161    if (!ModuleManager) {
1162      if (!hasASTContext())
1163        createASTContext();
1164
1165      std::string Sysroot = getHeaderSearchOpts().Sysroot;
1166      const PreprocessorOptions &PPOpts = getPreprocessorOpts();
1167      ModuleManager = new ASTReader(getPreprocessor(), *Context,
1168                                    Sysroot.empty() ? "" : Sysroot.c_str(),
1169                                    PPOpts.DisablePCHValidation,
1170                                    PPOpts.DisableStatCache);
1171      if (hasASTConsumer()) {
1172        ModuleManager->setDeserializationListener(
1173          getASTConsumer().GetASTDeserializationListener());
1174        getASTContext().setASTMutationListener(
1175          getASTConsumer().GetASTMutationListener());
1176      }
1177      llvm::OwningPtr<ExternalASTSource> Source;
1178      Source.reset(ModuleManager);
1179      getASTContext().setExternalSource(Source);
1180      if (hasSema())
1181        ModuleManager->InitializeSema(getSema());
1182      if (hasASTConsumer())
1183        ModuleManager->StartTranslationUnit(&getASTConsumer());
1184    }
1185
1186    // Try to load the module we found.
1187    switch (ModuleManager->ReadAST(ModuleFile->getName(),
1188                                   serialization::MK_Module)) {
1189    case ASTReader::Success:
1190      break;
1191
1192    case ASTReader::IgnorePCH:
1193      // FIXME: The ASTReader will already have complained, but can we showhorn
1194      // that diagnostic information into a more useful form?
1195      KnownModules[Path[0].first] = 0;
1196      return 0;
1197
1198    case ASTReader::Failure:
1199      // Already complained, but note now that we failed.
1200      KnownModules[Path[0].first] = 0;
1201      return 0;
1202    }
1203
1204    if (!Module) {
1205      // If we loaded the module directly, without finding a module map first,
1206      // we'll have loaded the module's information from the module itself.
1207      Module = PP->getHeaderSearchInfo().getModuleMap()
1208                 .findModule((Path[0].first->getName()));
1209    }
1210
1211    // Cache the result of this top-level module lookup for later.
1212    Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
1213  }
1214
1215  // If we never found the module, fail.
1216  if (!Module)
1217    return 0;
1218
1219  // Verify that the rest of the module path actually corresponds to
1220  // a submodule.
1221  if (Path.size() > 1) {
1222    for (unsigned I = 1, N = Path.size(); I != N; ++I) {
1223      StringRef Name = Path[I].first->getName();
1224      clang::Module *Sub = Module->findSubmodule(Name);
1225
1226      if (!Sub) {
1227        // Attempt to perform typo correction to find a module name that works.
1228        llvm::SmallVector<StringRef, 2> Best;
1229        unsigned BestEditDistance = (std::numeric_limits<unsigned>::max)();
1230
1231        for (clang::Module::submodule_iterator J = Module->submodule_begin(),
1232                                            JEnd = Module->submodule_end();
1233             J != JEnd; ++J) {
1234          unsigned ED = Name.edit_distance((*J)->Name,
1235                                           /*AllowReplacements=*/true,
1236                                           BestEditDistance);
1237          if (ED <= BestEditDistance) {
1238            if (ED < BestEditDistance) {
1239              Best.clear();
1240              BestEditDistance = ED;
1241            }
1242
1243            Best.push_back((*J)->Name);
1244          }
1245        }
1246
1247        // If there was a clear winner, user it.
1248        if (Best.size() == 1) {
1249          getDiagnostics().Report(Path[I].second,
1250                                  diag::err_no_submodule_suggest)
1251            << Path[I].first << Module->getFullModuleName() << Best[0]
1252            << SourceRange(Path[0].second, Path[I-1].second)
1253            << FixItHint::CreateReplacement(SourceRange(Path[I].second),
1254                                            Best[0]);
1255
1256          Sub = Module->findSubmodule(Best[0]);
1257        }
1258      }
1259
1260      if (!Sub) {
1261        // No submodule by this name. Complain, and don't look for further
1262        // submodules.
1263        getDiagnostics().Report(Path[I].second, diag::err_no_submodule)
1264          << Path[I].first << Module->getFullModuleName()
1265          << SourceRange(Path[0].second, Path[I-1].second);
1266        break;
1267      }
1268
1269      Module = Sub;
1270    }
1271  }
1272
1273  // Make the named module visible, if it's not already part of the module
1274  // we are parsing.
1275  if (ModuleName != getLangOpts().CurrentModule) {
1276    if (!Module->IsFromModuleFile) {
1277      // We have an umbrella header or directory that doesn't actually include
1278      // all of the headers within the directory it covers. Complain about
1279      // this missing submodule and recover by forgetting that we ever saw
1280      // this submodule.
1281      // FIXME: Should we detect this at module load time? It seems fairly
1282      // expensive (and rare).
1283      getDiagnostics().Report(ImportLoc, diag::warn_missing_submodule)
1284        << Module->getFullModuleName()
1285        << SourceRange(Path.front().second, Path.back().second);
1286
1287      return 0;
1288    }
1289
1290    // Check whether this module is available.
1291    StringRef Feature;
1292    if (!Module->isAvailable(getLangOpts(), Feature)) {
1293      getDiagnostics().Report(ImportLoc, diag::err_module_unavailable)
1294        << Module->getFullModuleName()
1295        << Feature
1296        << SourceRange(Path.front().second, Path.back().second);
1297      LastModuleImportLoc = ImportLoc;
1298      LastModuleImportResult = 0;
1299      return 0;
1300    }
1301
1302    ModuleManager->makeModuleVisible(Module, Visibility);
1303  }
1304
1305  // If this module import was due to an inclusion directive, create an
1306  // implicit import declaration to capture it in the AST.
1307  if (IsInclusionDirective && hasASTContext()) {
1308    TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
1309    TU->addDecl(ImportDecl::CreateImplicit(getASTContext(), TU,
1310                                           ImportLoc, Module,
1311                                           Path.back().second));
1312  }
1313
1314  LastModuleImportLoc = ImportLoc;
1315  LastModuleImportResult = Module;
1316  return Module;
1317}
1318