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      1 //===--- FrontendActions.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/FrontendActions.h"
     11 #include "clang/AST/ASTConsumer.h"
     12 #include "clang/Basic/FileManager.h"
     13 #include "clang/Frontend/ASTConsumers.h"
     14 #include "clang/Frontend/ASTUnit.h"
     15 #include "clang/Frontend/CompilerInstance.h"
     16 #include "clang/Frontend/FrontendDiagnostic.h"
     17 #include "clang/Frontend/Utils.h"
     18 #include "clang/Lex/HeaderSearch.h"
     19 #include "clang/Lex/Pragma.h"
     20 #include "clang/Lex/Preprocessor.h"
     21 #include "clang/Parse/Parser.h"
     22 #include "clang/Serialization/ASTReader.h"
     23 #include "clang/Serialization/ASTWriter.h"
     24 #include "llvm/ADT/OwningPtr.h"
     25 #include "llvm/Support/FileSystem.h"
     26 #include "llvm/Support/MemoryBuffer.h"
     27 #include "llvm/Support/raw_ostream.h"
     28 #include "llvm/Support/system_error.h"
     29 
     30 using namespace clang;
     31 
     32 //===----------------------------------------------------------------------===//
     33 // Custom Actions
     34 //===----------------------------------------------------------------------===//
     35 
     36 ASTConsumer *InitOnlyAction::CreateASTConsumer(CompilerInstance &CI,
     37                                                StringRef InFile) {
     38   return new ASTConsumer();
     39 }
     40 
     41 void InitOnlyAction::ExecuteAction() {
     42 }
     43 
     44 //===----------------------------------------------------------------------===//
     45 // AST Consumer Actions
     46 //===----------------------------------------------------------------------===//
     47 
     48 ASTConsumer *ASTPrintAction::CreateASTConsumer(CompilerInstance &CI,
     49                                                StringRef InFile) {
     50   if (raw_ostream *OS = CI.createDefaultOutputFile(false, InFile))
     51     return CreateASTPrinter(OS, CI.getFrontendOpts().ASTDumpFilter);
     52   return 0;
     53 }
     54 
     55 ASTConsumer *ASTDumpAction::CreateASTConsumer(CompilerInstance &CI,
     56                                               StringRef InFile) {
     57   return CreateASTDumper(CI.getFrontendOpts().ASTDumpFilter,
     58                          CI.getFrontendOpts().ASTDumpLookups);
     59 }
     60 
     61 ASTConsumer *ASTDeclListAction::CreateASTConsumer(CompilerInstance &CI,
     62                                                   StringRef InFile) {
     63   return CreateASTDeclNodeLister();
     64 }
     65 
     66 ASTConsumer *ASTDumpXMLAction::CreateASTConsumer(CompilerInstance &CI,
     67                                                  StringRef InFile) {
     68   raw_ostream *OS;
     69   if (CI.getFrontendOpts().OutputFile.empty())
     70     OS = &llvm::outs();
     71   else
     72     OS = CI.createDefaultOutputFile(false, InFile);
     73   if (!OS) return 0;
     74   return CreateASTDumperXML(*OS);
     75 }
     76 
     77 ASTConsumer *ASTViewAction::CreateASTConsumer(CompilerInstance &CI,
     78                                               StringRef InFile) {
     79   return CreateASTViewer();
     80 }
     81 
     82 ASTConsumer *DeclContextPrintAction::CreateASTConsumer(CompilerInstance &CI,
     83                                                        StringRef InFile) {
     84   return CreateDeclContextPrinter();
     85 }
     86 
     87 ASTConsumer *GeneratePCHAction::CreateASTConsumer(CompilerInstance &CI,
     88                                                   StringRef InFile) {
     89   std::string Sysroot;
     90   std::string OutputFile;
     91   raw_ostream *OS = 0;
     92   if (ComputeASTConsumerArguments(CI, InFile, Sysroot, OutputFile, OS))
     93     return 0;
     94 
     95   if (!CI.getFrontendOpts().RelocatablePCH)
     96     Sysroot.clear();
     97   return new PCHGenerator(CI.getPreprocessor(), OutputFile, 0, Sysroot, OS);
     98 }
     99 
    100 bool GeneratePCHAction::ComputeASTConsumerArguments(CompilerInstance &CI,
    101                                                     StringRef InFile,
    102                                                     std::string &Sysroot,
    103                                                     std::string &OutputFile,
    104                                                     raw_ostream *&OS) {
    105   Sysroot = CI.getHeaderSearchOpts().Sysroot;
    106   if (CI.getFrontendOpts().RelocatablePCH && Sysroot.empty()) {
    107     CI.getDiagnostics().Report(diag::err_relocatable_without_isysroot);
    108     return true;
    109   }
    110 
    111   // We use createOutputFile here because this is exposed via libclang, and we
    112   // must disable the RemoveFileOnSignal behavior.
    113   // We use a temporary to avoid race conditions.
    114   OS = CI.createOutputFile(CI.getFrontendOpts().OutputFile, /*Binary=*/true,
    115                            /*RemoveFileOnSignal=*/false, InFile,
    116                            /*Extension=*/"", /*useTemporary=*/true);
    117   if (!OS)
    118     return true;
    119 
    120   OutputFile = CI.getFrontendOpts().OutputFile;
    121   return false;
    122 }
    123 
    124 ASTConsumer *GenerateModuleAction::CreateASTConsumer(CompilerInstance &CI,
    125                                                      StringRef InFile) {
    126   std::string Sysroot;
    127   std::string OutputFile;
    128   raw_ostream *OS = 0;
    129   if (ComputeASTConsumerArguments(CI, InFile, Sysroot, OutputFile, OS))
    130     return 0;
    131 
    132   return new PCHGenerator(CI.getPreprocessor(), OutputFile, Module,
    133                           Sysroot, OS);
    134 }
    135 
    136 static SmallVectorImpl<char> &
    137 operator+=(SmallVectorImpl<char> &Includes, StringRef RHS) {
    138   Includes.append(RHS.begin(), RHS.end());
    139   return Includes;
    140 }
    141 
    142 static void addHeaderInclude(StringRef HeaderName,
    143                              SmallVectorImpl<char> &Includes,
    144                              const LangOptions &LangOpts) {
    145   if (LangOpts.ObjC1)
    146     Includes += "#import \"";
    147   else
    148     Includes += "#include \"";
    149   Includes += HeaderName;
    150   Includes += "\"\n";
    151 }
    152 
    153 static void addHeaderInclude(const FileEntry *Header,
    154                              SmallVectorImpl<char> &Includes,
    155                              const LangOptions &LangOpts) {
    156   addHeaderInclude(Header->getName(), Includes, LangOpts);
    157 }
    158 
    159 /// \brief Collect the set of header includes needed to construct the given
    160 /// module and update the TopHeaders file set of the module.
    161 ///
    162 /// \param Module The module we're collecting includes from.
    163 ///
    164 /// \param Includes Will be augmented with the set of \#includes or \#imports
    165 /// needed to load all of the named headers.
    166 static void collectModuleHeaderIncludes(const LangOptions &LangOpts,
    167                                         FileManager &FileMgr,
    168                                         ModuleMap &ModMap,
    169                                         clang::Module *Module,
    170                                         SmallVectorImpl<char> &Includes) {
    171   // Don't collect any headers for unavailable modules.
    172   if (!Module->isAvailable())
    173     return;
    174 
    175   // Add includes for each of these headers.
    176   for (unsigned I = 0, N = Module->NormalHeaders.size(); I != N; ++I) {
    177     const FileEntry *Header = Module->NormalHeaders[I];
    178     Module->addTopHeader(Header);
    179     addHeaderInclude(Header, Includes, LangOpts);
    180   }
    181   // Note that Module->PrivateHeaders will not be a TopHeader.
    182 
    183   if (const FileEntry *UmbrellaHeader = Module->getUmbrellaHeader()) {
    184     Module->addTopHeader(UmbrellaHeader);
    185     if (Module->Parent) {
    186       // Include the umbrella header for submodules.
    187       addHeaderInclude(UmbrellaHeader, Includes, LangOpts);
    188     }
    189   } else if (const DirectoryEntry *UmbrellaDir = Module->getUmbrellaDir()) {
    190     // Add all of the headers we find in this subdirectory.
    191     llvm::error_code EC;
    192     SmallString<128> DirNative;
    193     llvm::sys::path::native(UmbrellaDir->getName(), DirNative);
    194     for (llvm::sys::fs::recursive_directory_iterator Dir(DirNative.str(), EC),
    195                                                      DirEnd;
    196          Dir != DirEnd && !EC; Dir.increment(EC)) {
    197       // Check whether this entry has an extension typically associated with
    198       // headers.
    199       if (!llvm::StringSwitch<bool>(llvm::sys::path::extension(Dir->path()))
    200           .Cases(".h", ".H", ".hh", ".hpp", true)
    201           .Default(false))
    202         continue;
    203 
    204       // If this header is marked 'unavailable' in this module, don't include
    205       // it.
    206       if (const FileEntry *Header = FileMgr.getFile(Dir->path())) {
    207         if (ModMap.isHeaderInUnavailableModule(Header))
    208           continue;
    209         Module->addTopHeader(Header);
    210       }
    211 
    212       // Include this header umbrella header for submodules.
    213       addHeaderInclude(Dir->path(), Includes, LangOpts);
    214     }
    215   }
    216 
    217   // Recurse into submodules.
    218   for (clang::Module::submodule_iterator Sub = Module->submodule_begin(),
    219                                       SubEnd = Module->submodule_end();
    220        Sub != SubEnd; ++Sub)
    221     collectModuleHeaderIncludes(LangOpts, FileMgr, ModMap, *Sub, Includes);
    222 }
    223 
    224 bool GenerateModuleAction::BeginSourceFileAction(CompilerInstance &CI,
    225                                                  StringRef Filename) {
    226   // Find the module map file.
    227   const FileEntry *ModuleMap = CI.getFileManager().getFile(Filename);
    228   if (!ModuleMap)  {
    229     CI.getDiagnostics().Report(diag::err_module_map_not_found)
    230       << Filename;
    231     return false;
    232   }
    233 
    234   // Parse the module map file.
    235   HeaderSearch &HS = CI.getPreprocessor().getHeaderSearchInfo();
    236   if (HS.loadModuleMapFile(ModuleMap, IsSystem))
    237     return false;
    238 
    239   if (CI.getLangOpts().CurrentModule.empty()) {
    240     CI.getDiagnostics().Report(diag::err_missing_module_name);
    241 
    242     // FIXME: Eventually, we could consider asking whether there was just
    243     // a single module described in the module map, and use that as a
    244     // default. Then it would be fairly trivial to just "compile" a module
    245     // map with a single module (the common case).
    246     return false;
    247   }
    248 
    249   // Dig out the module definition.
    250   Module = HS.lookupModule(CI.getLangOpts().CurrentModule,
    251                            /*AllowSearch=*/false);
    252   if (!Module) {
    253     CI.getDiagnostics().Report(diag::err_missing_module)
    254       << CI.getLangOpts().CurrentModule << Filename;
    255 
    256     return false;
    257   }
    258 
    259   // Check whether we can build this module at all.
    260   StringRef Feature;
    261   if (!Module->isAvailable(CI.getLangOpts(), CI.getTarget(), Feature)) {
    262     CI.getDiagnostics().Report(diag::err_module_unavailable)
    263       << Module->getFullModuleName()
    264       << Feature;
    265 
    266     return false;
    267   }
    268 
    269   FileManager &FileMgr = CI.getFileManager();
    270 
    271   // Collect the set of #includes we need to build the module.
    272   SmallString<256> HeaderContents;
    273   if (const FileEntry *UmbrellaHeader = Module->getUmbrellaHeader())
    274     addHeaderInclude(UmbrellaHeader, HeaderContents, CI.getLangOpts());
    275   collectModuleHeaderIncludes(CI.getLangOpts(), FileMgr,
    276     CI.getPreprocessor().getHeaderSearchInfo().getModuleMap(),
    277     Module, HeaderContents);
    278 
    279   llvm::MemoryBuffer *InputBuffer =
    280       llvm::MemoryBuffer::getMemBufferCopy(HeaderContents,
    281                                            Module::getModuleInputBufferName());
    282   // Ownership of InputBuffer will be transfered to the SourceManager.
    283   setCurrentInput(FrontendInputFile(InputBuffer, getCurrentFileKind(),
    284                                     Module->IsSystem));
    285   return true;
    286 }
    287 
    288 bool GenerateModuleAction::ComputeASTConsumerArguments(CompilerInstance &CI,
    289                                                        StringRef InFile,
    290                                                        std::string &Sysroot,
    291                                                        std::string &OutputFile,
    292                                                        raw_ostream *&OS) {
    293   // If no output file was provided, figure out where this module would go
    294   // in the module cache.
    295   if (CI.getFrontendOpts().OutputFile.empty()) {
    296     HeaderSearch &HS = CI.getPreprocessor().getHeaderSearchInfo();
    297     SmallString<256> ModuleFileName(HS.getModuleCachePath());
    298     llvm::sys::path::append(ModuleFileName,
    299                             CI.getLangOpts().CurrentModule + ".pcm");
    300     CI.getFrontendOpts().OutputFile = ModuleFileName.str();
    301   }
    302 
    303   // We use createOutputFile here because this is exposed via libclang, and we
    304   // must disable the RemoveFileOnSignal behavior.
    305   // We use a temporary to avoid race conditions.
    306   OS = CI.createOutputFile(CI.getFrontendOpts().OutputFile, /*Binary=*/true,
    307                            /*RemoveFileOnSignal=*/false, InFile,
    308                            /*Extension=*/"", /*useTemporary=*/true,
    309                            /*CreateMissingDirectories=*/true);
    310   if (!OS)
    311     return true;
    312 
    313   OutputFile = CI.getFrontendOpts().OutputFile;
    314   return false;
    315 }
    316 
    317 ASTConsumer *SyntaxOnlyAction::CreateASTConsumer(CompilerInstance &CI,
    318                                                  StringRef InFile) {
    319   return new ASTConsumer();
    320 }
    321 
    322 ASTConsumer *DumpModuleInfoAction::CreateASTConsumer(CompilerInstance &CI,
    323                                                      StringRef InFile) {
    324   return new ASTConsumer();
    325 }
    326 
    327 namespace {
    328   /// \brief AST reader listener that dumps module information for a module
    329   /// file.
    330   class DumpModuleInfoListener : public ASTReaderListener {
    331     llvm::raw_ostream &Out;
    332 
    333   public:
    334     DumpModuleInfoListener(llvm::raw_ostream &Out) : Out(Out) { }
    335 
    336 #define DUMP_BOOLEAN(Value, Text)                       \
    337     Out.indent(4) << Text << ": " << (Value? "Yes" : "No") << "\n"
    338 
    339     virtual bool ReadFullVersionInformation(StringRef FullVersion) {
    340       Out.indent(2)
    341         << "Generated by "
    342         << (FullVersion == getClangFullRepositoryVersion()? "this"
    343                                                           : "a different")
    344         << " Clang: " << FullVersion << "\n";
    345       return ASTReaderListener::ReadFullVersionInformation(FullVersion);
    346     }
    347 
    348     virtual bool ReadLanguageOptions(const LangOptions &LangOpts,
    349                                      bool Complain) {
    350       Out.indent(2) << "Language options:\n";
    351 #define LANGOPT(Name, Bits, Default, Description) \
    352       DUMP_BOOLEAN(LangOpts.Name, Description);
    353 #define ENUM_LANGOPT(Name, Type, Bits, Default, Description) \
    354       Out.indent(4) << Description << ": "                   \
    355                     << static_cast<unsigned>(LangOpts.get##Name()) << "\n";
    356 #define VALUE_LANGOPT(Name, Bits, Default, Description) \
    357       Out.indent(4) << Description << ": " << LangOpts.Name << "\n";
    358 #define BENIGN_LANGOPT(Name, Bits, Default, Description)
    359 #define BENIGN_ENUM_LANGOPT(Name, Type, Bits, Default, Description)
    360 #include "clang/Basic/LangOptions.def"
    361       return false;
    362     }
    363 
    364     virtual bool ReadTargetOptions(const TargetOptions &TargetOpts,
    365                                    bool Complain) {
    366       Out.indent(2) << "Target options:\n";
    367       Out.indent(4) << "  Triple: " << TargetOpts.Triple << "\n";
    368       Out.indent(4) << "  CPU: " << TargetOpts.CPU << "\n";
    369       Out.indent(4) << "  ABI: " << TargetOpts.ABI << "\n";
    370       Out.indent(4) << "  C++ ABI: " << TargetOpts.CXXABI << "\n";
    371       Out.indent(4) << "  Linker version: " << TargetOpts.LinkerVersion << "\n";
    372 
    373       if (!TargetOpts.FeaturesAsWritten.empty()) {
    374         Out.indent(4) << "Target features:\n";
    375         for (unsigned I = 0, N = TargetOpts.FeaturesAsWritten.size();
    376              I != N; ++I) {
    377           Out.indent(6) << TargetOpts.FeaturesAsWritten[I] << "\n";
    378         }
    379       }
    380 
    381       return false;
    382     }
    383 
    384     virtual bool ReadHeaderSearchOptions(const HeaderSearchOptions &HSOpts,
    385                                          bool Complain) {
    386       Out.indent(2) << "Header search options:\n";
    387       Out.indent(4) << "System root [-isysroot=]: '" << HSOpts.Sysroot << "'\n";
    388       DUMP_BOOLEAN(HSOpts.UseBuiltinIncludes,
    389                    "Use builtin include directories [-nobuiltininc]");
    390       DUMP_BOOLEAN(HSOpts.UseStandardSystemIncludes,
    391                    "Use standard system include directories [-nostdinc]");
    392       DUMP_BOOLEAN(HSOpts.UseStandardCXXIncludes,
    393                    "Use standard C++ include directories [-nostdinc++]");
    394       DUMP_BOOLEAN(HSOpts.UseLibcxx,
    395                    "Use libc++ (rather than libstdc++) [-stdlib=]");
    396       return false;
    397     }
    398 
    399     virtual bool ReadPreprocessorOptions(const PreprocessorOptions &PPOpts,
    400                                          bool Complain,
    401                                          std::string &SuggestedPredefines) {
    402       Out.indent(2) << "Preprocessor options:\n";
    403       DUMP_BOOLEAN(PPOpts.UsePredefines,
    404                    "Uses compiler/target-specific predefines [-undef]");
    405       DUMP_BOOLEAN(PPOpts.DetailedRecord,
    406                    "Uses detailed preprocessing record (for indexing)");
    407 
    408       if (!PPOpts.Macros.empty()) {
    409         Out.indent(4) << "Predefined macros:\n";
    410       }
    411 
    412       for (std::vector<std::pair<std::string, bool/*isUndef*/> >::const_iterator
    413              I = PPOpts.Macros.begin(), IEnd = PPOpts.Macros.end();
    414            I != IEnd; ++I) {
    415         Out.indent(6);
    416         if (I->second)
    417           Out << "-U";
    418         else
    419           Out << "-D";
    420         Out << I->first << "\n";
    421       }
    422       return false;
    423     }
    424 #undef DUMP_BOOLEAN
    425   };
    426 }
    427 
    428 void DumpModuleInfoAction::ExecuteAction() {
    429   // Set up the output file.
    430   llvm::OwningPtr<llvm::raw_fd_ostream> OutFile;
    431   StringRef OutputFileName = getCompilerInstance().getFrontendOpts().OutputFile;
    432   if (!OutputFileName.empty() && OutputFileName != "-") {
    433     std::string ErrorInfo;
    434     OutFile.reset(new llvm::raw_fd_ostream(OutputFileName.str().c_str(),
    435                                            ErrorInfo));
    436   }
    437   llvm::raw_ostream &Out = OutFile.get()? *OutFile.get() : llvm::outs();
    438 
    439   Out << "Information for module file '" << getCurrentFile() << "':\n";
    440   DumpModuleInfoListener Listener(Out);
    441   ASTReader::readASTFileControlBlock(getCurrentFile(),
    442                                      getCompilerInstance().getFileManager(),
    443                                      Listener);
    444 }
    445 
    446 //===----------------------------------------------------------------------===//
    447 // Preprocessor Actions
    448 //===----------------------------------------------------------------------===//
    449 
    450 void DumpRawTokensAction::ExecuteAction() {
    451   Preprocessor &PP = getCompilerInstance().getPreprocessor();
    452   SourceManager &SM = PP.getSourceManager();
    453 
    454   // Start lexing the specified input file.
    455   const llvm::MemoryBuffer *FromFile = SM.getBuffer(SM.getMainFileID());
    456   Lexer RawLex(SM.getMainFileID(), FromFile, SM, PP.getLangOpts());
    457   RawLex.SetKeepWhitespaceMode(true);
    458 
    459   Token RawTok;
    460   RawLex.LexFromRawLexer(RawTok);
    461   while (RawTok.isNot(tok::eof)) {
    462     PP.DumpToken(RawTok, true);
    463     llvm::errs() << "\n";
    464     RawLex.LexFromRawLexer(RawTok);
    465   }
    466 }
    467 
    468 void DumpTokensAction::ExecuteAction() {
    469   Preprocessor &PP = getCompilerInstance().getPreprocessor();
    470   // Start preprocessing the specified input file.
    471   Token Tok;
    472   PP.EnterMainSourceFile();
    473   do {
    474     PP.Lex(Tok);
    475     PP.DumpToken(Tok, true);
    476     llvm::errs() << "\n";
    477   } while (Tok.isNot(tok::eof));
    478 }
    479 
    480 void GeneratePTHAction::ExecuteAction() {
    481   CompilerInstance &CI = getCompilerInstance();
    482   if (CI.getFrontendOpts().OutputFile.empty() ||
    483       CI.getFrontendOpts().OutputFile == "-") {
    484     // FIXME: Don't fail this way.
    485     // FIXME: Verify that we can actually seek in the given file.
    486     llvm::report_fatal_error("PTH requires a seekable file for output!");
    487   }
    488   llvm::raw_fd_ostream *OS =
    489     CI.createDefaultOutputFile(true, getCurrentFile());
    490   if (!OS) return;
    491 
    492   CacheTokens(CI.getPreprocessor(), OS);
    493 }
    494 
    495 void PreprocessOnlyAction::ExecuteAction() {
    496   Preprocessor &PP = getCompilerInstance().getPreprocessor();
    497 
    498   // Ignore unknown pragmas.
    499   PP.AddPragmaHandler(new EmptyPragmaHandler());
    500 
    501   Token Tok;
    502   // Start parsing the specified input file.
    503   PP.EnterMainSourceFile();
    504   do {
    505     PP.Lex(Tok);
    506   } while (Tok.isNot(tok::eof));
    507 }
    508 
    509 void PrintPreprocessedAction::ExecuteAction() {
    510   CompilerInstance &CI = getCompilerInstance();
    511   // Output file may need to be set to 'Binary', to avoid converting Unix style
    512   // line feeds (<LF>) to Microsoft style line feeds (<CR><LF>).
    513   //
    514   // Look to see what type of line endings the file uses. If there's a
    515   // CRLF, then we won't open the file up in binary mode. If there is
    516   // just an LF or CR, then we will open the file up in binary mode.
    517   // In this fashion, the output format should match the input format, unless
    518   // the input format has inconsistent line endings.
    519   //
    520   // This should be a relatively fast operation since most files won't have
    521   // all of their source code on a single line. However, that is still a
    522   // concern, so if we scan for too long, we'll just assume the file should
    523   // be opened in binary mode.
    524   bool BinaryMode = true;
    525   bool InvalidFile = false;
    526   const SourceManager& SM = CI.getSourceManager();
    527   const llvm::MemoryBuffer *Buffer = SM.getBuffer(SM.getMainFileID(),
    528                                                      &InvalidFile);
    529   if (!InvalidFile) {
    530     const char *cur = Buffer->getBufferStart();
    531     const char *end = Buffer->getBufferEnd();
    532     const char *next = (cur != end) ? cur + 1 : end;
    533 
    534     // Limit ourselves to only scanning 256 characters into the source
    535     // file.  This is mostly a sanity check in case the file has no
    536     // newlines whatsoever.
    537     if (end - cur > 256) end = cur + 256;
    538 
    539     while (next < end) {
    540       if (*cur == 0x0D) {  // CR
    541         if (*next == 0x0A)  // CRLF
    542           BinaryMode = false;
    543 
    544         break;
    545       } else if (*cur == 0x0A)  // LF
    546         break;
    547 
    548       ++cur, ++next;
    549     }
    550   }
    551 
    552   raw_ostream *OS = CI.createDefaultOutputFile(BinaryMode, getCurrentFile());
    553   if (!OS) return;
    554 
    555   DoPrintPreprocessedInput(CI.getPreprocessor(), OS,
    556                            CI.getPreprocessorOutputOpts());
    557 }
    558 
    559 void PrintPreambleAction::ExecuteAction() {
    560   switch (getCurrentFileKind()) {
    561   case IK_C:
    562   case IK_CXX:
    563   case IK_ObjC:
    564   case IK_ObjCXX:
    565   case IK_OpenCL:
    566   case IK_CUDA:
    567     break;
    568 
    569   case IK_None:
    570   case IK_Asm:
    571   case IK_PreprocessedC:
    572   case IK_PreprocessedCXX:
    573   case IK_PreprocessedObjC:
    574   case IK_PreprocessedObjCXX:
    575   case IK_AST:
    576   case IK_LLVM_IR:
    577     // We can't do anything with these.
    578     return;
    579   }
    580 
    581   CompilerInstance &CI = getCompilerInstance();
    582   llvm::MemoryBuffer *Buffer
    583       = CI.getFileManager().getBufferForFile(getCurrentFile());
    584   if (Buffer) {
    585     unsigned Preamble = Lexer::ComputePreamble(Buffer, CI.getLangOpts()).first;
    586     llvm::outs().write(Buffer->getBufferStart(), Preamble);
    587     delete Buffer;
    588   }
    589 }
    590