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/CompilerInstance.h"
15 #include "clang/Frontend/FrontendDiagnostic.h"
16 #include "clang/Frontend/MultiplexConsumer.h"
17 #include "clang/Frontend/Utils.h"
18 #include "clang/Lex/HeaderSearch.h"
19 #include "clang/Lex/Preprocessor.h"
20 #include "clang/Lex/PreprocessorOptions.h"
21 #include "clang/Serialization/ASTReader.h"
22 #include "clang/Serialization/ASTWriter.h"
23 #include "llvm/Support/FileSystem.h"
24 #include "llvm/Support/MemoryBuffer.h"
25 #include "llvm/Support/Path.h"
26 #include "llvm/Support/raw_ostream.h"
27 #include <memory>
28 #include <system_error>
29 
30 using namespace clang;
31 
32 //===----------------------------------------------------------------------===//
33 // Custom Actions
34 //===----------------------------------------------------------------------===//
35 
36 std::unique_ptr<ASTConsumer>
37 InitOnlyAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
38   return llvm::make_unique<ASTConsumer>();
39 }
40 
41 void InitOnlyAction::ExecuteAction() {
42 }
43 
44 //===----------------------------------------------------------------------===//
45 // AST Consumer Actions
46 //===----------------------------------------------------------------------===//
47 
48 std::unique_ptr<ASTConsumer>
49 ASTPrintAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
50   if (std::unique_ptr<raw_ostream> OS =
51           CI.createDefaultOutputFile(false, InFile))
52     return CreateASTPrinter(std::move(OS), CI.getFrontendOpts().ASTDumpFilter);
53   return nullptr;
54 }
55 
56 std::unique_ptr<ASTConsumer>
57 ASTDumpAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
58   return CreateASTDumper(CI.getFrontendOpts().ASTDumpFilter,
59                          CI.getFrontendOpts().ASTDumpDecls,
60                          CI.getFrontendOpts().ASTDumpAll,
61                          CI.getFrontendOpts().ASTDumpLookups);
62 }
63 
64 std::unique_ptr<ASTConsumer>
65 ASTDeclListAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
66   return CreateASTDeclNodeLister();
67 }
68 
69 std::unique_ptr<ASTConsumer>
70 ASTViewAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
71   return CreateASTViewer();
72 }
73 
74 std::unique_ptr<ASTConsumer>
75 DeclContextPrintAction::CreateASTConsumer(CompilerInstance &CI,
76                                           StringRef InFile) {
77   return CreateDeclContextPrinter();
78 }
79 
80 std::unique_ptr<ASTConsumer>
81 GeneratePCHAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
82   std::string Sysroot;
83   std::string OutputFile;
84   std::unique_ptr<raw_pwrite_stream> OS =
85       ComputeASTConsumerArguments(CI, InFile, Sysroot, OutputFile);
86   if (!OS)
87     return nullptr;
88 
89   if (!CI.getFrontendOpts().RelocatablePCH)
90     Sysroot.clear();
91 
92   auto Buffer = std::make_shared<PCHBuffer>();
93   std::vector<std::unique_ptr<ASTConsumer>> Consumers;
94   Consumers.push_back(llvm::make_unique<PCHGenerator>(
95                         CI.getPreprocessor(), OutputFile, Sysroot,
96                         Buffer, CI.getFrontendOpts().ModuleFileExtensions,
97       /*AllowASTWithErrors*/CI.getPreprocessorOpts().AllowPCHWithCompilerErrors,
98                         /*IncludeTimestamps*/
99                           +CI.getFrontendOpts().IncludeTimestamps));
100   Consumers.push_back(CI.getPCHContainerWriter().CreatePCHContainerGenerator(
101       CI, InFile, OutputFile, std::move(OS), Buffer));
102 
103   return llvm::make_unique<MultiplexConsumer>(std::move(Consumers));
104 }
105 
106 std::unique_ptr<raw_pwrite_stream>
107 GeneratePCHAction::ComputeASTConsumerArguments(CompilerInstance &CI,
108                                                StringRef InFile,
109                                                std::string &Sysroot,
110                                                std::string &OutputFile) {
111   Sysroot = CI.getHeaderSearchOpts().Sysroot;
112   if (CI.getFrontendOpts().RelocatablePCH && Sysroot.empty()) {
113     CI.getDiagnostics().Report(diag::err_relocatable_without_isysroot);
114     return nullptr;
115   }
116 
117   // We use createOutputFile here because this is exposed via libclang, and we
118   // must disable the RemoveFileOnSignal behavior.
119   // We use a temporary to avoid race conditions.
120   std::unique_ptr<raw_pwrite_stream> OS =
121       CI.createOutputFile(CI.getFrontendOpts().OutputFile, /*Binary=*/true,
122                           /*RemoveFileOnSignal=*/false, InFile,
123                           /*Extension=*/"", /*useTemporary=*/true);
124   if (!OS)
125     return nullptr;
126 
127   OutputFile = CI.getFrontendOpts().OutputFile;
128   return OS;
129 }
130 
131 bool GeneratePCHAction::shouldEraseOutputFiles() {
132   if (getCompilerInstance().getPreprocessorOpts().AllowPCHWithCompilerErrors)
133     return false;
134   return ASTFrontendAction::shouldEraseOutputFiles();
135 }
136 
137 bool GeneratePCHAction::BeginSourceFileAction(CompilerInstance &CI) {
138   CI.getLangOpts().CompilingPCH = true;
139   return true;
140 }
141 
142 std::unique_ptr<ASTConsumer>
143 GenerateModuleAction::CreateASTConsumer(CompilerInstance &CI,
144                                         StringRef InFile) {
145   std::unique_ptr<raw_pwrite_stream> OS = CreateOutputFile(CI, InFile);
146   if (!OS)
147     return nullptr;
148 
149   std::string OutputFile = CI.getFrontendOpts().OutputFile;
150   std::string Sysroot;
151 
152   auto Buffer = std::make_shared<PCHBuffer>();
153   std::vector<std::unique_ptr<ASTConsumer>> Consumers;
154 
155   Consumers.push_back(llvm::make_unique<PCHGenerator>(
156                         CI.getPreprocessor(), OutputFile, Sysroot,
157                         Buffer, CI.getFrontendOpts().ModuleFileExtensions,
158                         /*AllowASTWithErrors=*/false,
159                         /*IncludeTimestamps=*/
160                           +CI.getFrontendOpts().BuildingImplicitModule));
161   Consumers.push_back(CI.getPCHContainerWriter().CreatePCHContainerGenerator(
162       CI, InFile, OutputFile, std::move(OS), Buffer));
163   return llvm::make_unique<MultiplexConsumer>(std::move(Consumers));
164 }
165 
166 std::unique_ptr<raw_pwrite_stream>
167 GenerateModuleFromModuleMapAction::CreateOutputFile(CompilerInstance &CI,
168                                                     StringRef InFile) {
169   // If no output file was provided, figure out where this module would go
170   // in the module cache.
171   if (CI.getFrontendOpts().OutputFile.empty()) {
172     StringRef ModuleMapFile = CI.getFrontendOpts().OriginalModuleMap;
173     if (ModuleMapFile.empty())
174       ModuleMapFile = InFile;
175 
176     HeaderSearch &HS = CI.getPreprocessor().getHeaderSearchInfo();
177     CI.getFrontendOpts().OutputFile =
178         HS.getModuleFileName(CI.getLangOpts().CurrentModule, ModuleMapFile,
179                              /*UsePrebuiltPath=*/false);
180   }
181 
182   // We use createOutputFile here because this is exposed via libclang, and we
183   // must disable the RemoveFileOnSignal behavior.
184   // We use a temporary to avoid race conditions.
185   return CI.createOutputFile(CI.getFrontendOpts().OutputFile, /*Binary=*/true,
186                              /*RemoveFileOnSignal=*/false, InFile,
187                              /*Extension=*/"", /*useTemporary=*/true,
188                              /*CreateMissingDirectories=*/true);
189 }
190 
191 bool GenerateModuleInterfaceAction::BeginSourceFileAction(
192     CompilerInstance &CI) {
193   if (!CI.getLangOpts().ModulesTS) {
194     CI.getDiagnostics().Report(diag::err_module_interface_requires_modules_ts);
195     return false;
196   }
197 
198   CI.getLangOpts().setCompilingModule(LangOptions::CMK_ModuleInterface);
199 
200   return GenerateModuleAction::BeginSourceFileAction(CI);
201 }
202 
203 std::unique_ptr<raw_pwrite_stream>
204 GenerateModuleInterfaceAction::CreateOutputFile(CompilerInstance &CI,
205                                                 StringRef InFile) {
206   return CI.createDefaultOutputFile(/*Binary=*/true, InFile, "pcm");
207 }
208 
209 SyntaxOnlyAction::~SyntaxOnlyAction() {
210 }
211 
212 std::unique_ptr<ASTConsumer>
213 SyntaxOnlyAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
214   return llvm::make_unique<ASTConsumer>();
215 }
216 
217 std::unique_ptr<ASTConsumer>
218 DumpModuleInfoAction::CreateASTConsumer(CompilerInstance &CI,
219                                         StringRef InFile) {
220   return llvm::make_unique<ASTConsumer>();
221 }
222 
223 std::unique_ptr<ASTConsumer>
224 VerifyPCHAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
225   return llvm::make_unique<ASTConsumer>();
226 }
227 
228 void VerifyPCHAction::ExecuteAction() {
229   CompilerInstance &CI = getCompilerInstance();
230   bool Preamble = CI.getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
231   const std::string &Sysroot = CI.getHeaderSearchOpts().Sysroot;
232   std::unique_ptr<ASTReader> Reader(new ASTReader(
233       CI.getPreprocessor(), &CI.getASTContext(), CI.getPCHContainerReader(),
234       CI.getFrontendOpts().ModuleFileExtensions,
235       Sysroot.empty() ? "" : Sysroot.c_str(),
236       /*DisableValidation*/ false,
237       /*AllowPCHWithCompilerErrors*/ false,
238       /*AllowConfigurationMismatch*/ true,
239       /*ValidateSystemInputs*/ true));
240 
241   Reader->ReadAST(getCurrentFile(),
242                   Preamble ? serialization::MK_Preamble
243                            : serialization::MK_PCH,
244                   SourceLocation(),
245                   ASTReader::ARR_ConfigurationMismatch);
246 }
247 
248 namespace {
249   /// \brief AST reader listener that dumps module information for a module
250   /// file.
251   class DumpModuleInfoListener : public ASTReaderListener {
252     llvm::raw_ostream &Out;
253 
254   public:
255     DumpModuleInfoListener(llvm::raw_ostream &Out) : Out(Out) { }
256 
257 #define DUMP_BOOLEAN(Value, Text)                       \
258     Out.indent(4) << Text << ": " << (Value? "Yes" : "No") << "\n"
259 
260     bool ReadFullVersionInformation(StringRef FullVersion) override {
261       Out.indent(2)
262         << "Generated by "
263         << (FullVersion == getClangFullRepositoryVersion()? "this"
264                                                           : "a different")
265         << " Clang: " << FullVersion << "\n";
266       return ASTReaderListener::ReadFullVersionInformation(FullVersion);
267     }
268 
269     void ReadModuleName(StringRef ModuleName) override {
270       Out.indent(2) << "Module name: " << ModuleName << "\n";
271     }
272     void ReadModuleMapFile(StringRef ModuleMapPath) override {
273       Out.indent(2) << "Module map file: " << ModuleMapPath << "\n";
274     }
275 
276     bool ReadLanguageOptions(const LangOptions &LangOpts, bool Complain,
277                              bool AllowCompatibleDifferences) override {
278       Out.indent(2) << "Language options:\n";
279 #define LANGOPT(Name, Bits, Default, Description) \
280       DUMP_BOOLEAN(LangOpts.Name, Description);
281 #define ENUM_LANGOPT(Name, Type, Bits, Default, Description) \
282       Out.indent(4) << Description << ": "                   \
283                     << static_cast<unsigned>(LangOpts.get##Name()) << "\n";
284 #define VALUE_LANGOPT(Name, Bits, Default, Description) \
285       Out.indent(4) << Description << ": " << LangOpts.Name << "\n";
286 #define BENIGN_LANGOPT(Name, Bits, Default, Description)
287 #define BENIGN_ENUM_LANGOPT(Name, Type, Bits, Default, Description)
288 #include "clang/Basic/LangOptions.def"
289 
290       if (!LangOpts.ModuleFeatures.empty()) {
291         Out.indent(4) << "Module features:\n";
292         for (StringRef Feature : LangOpts.ModuleFeatures)
293           Out.indent(6) << Feature << "\n";
294       }
295 
296       return false;
297     }
298 
299     bool ReadTargetOptions(const TargetOptions &TargetOpts, bool Complain,
300                            bool AllowCompatibleDifferences) override {
301       Out.indent(2) << "Target options:\n";
302       Out.indent(4) << "  Triple: " << TargetOpts.Triple << "\n";
303       Out.indent(4) << "  CPU: " << TargetOpts.CPU << "\n";
304       Out.indent(4) << "  ABI: " << TargetOpts.ABI << "\n";
305 
306       if (!TargetOpts.FeaturesAsWritten.empty()) {
307         Out.indent(4) << "Target features:\n";
308         for (unsigned I = 0, N = TargetOpts.FeaturesAsWritten.size();
309              I != N; ++I) {
310           Out.indent(6) << TargetOpts.FeaturesAsWritten[I] << "\n";
311         }
312       }
313 
314       return false;
315     }
316 
317     bool ReadDiagnosticOptions(IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts,
318                                bool Complain) override {
319       Out.indent(2) << "Diagnostic options:\n";
320 #define DIAGOPT(Name, Bits, Default) DUMP_BOOLEAN(DiagOpts->Name, #Name);
321 #define ENUM_DIAGOPT(Name, Type, Bits, Default) \
322       Out.indent(4) << #Name << ": " << DiagOpts->get##Name() << "\n";
323 #define VALUE_DIAGOPT(Name, Bits, Default) \
324       Out.indent(4) << #Name << ": " << DiagOpts->Name << "\n";
325 #include "clang/Basic/DiagnosticOptions.def"
326 
327       Out.indent(4) << "Diagnostic flags:\n";
328       for (const std::string &Warning : DiagOpts->Warnings)
329         Out.indent(6) << "-W" << Warning << "\n";
330       for (const std::string &Remark : DiagOpts->Remarks)
331         Out.indent(6) << "-R" << Remark << "\n";
332 
333       return false;
334     }
335 
336     bool ReadHeaderSearchOptions(const HeaderSearchOptions &HSOpts,
337                                  StringRef SpecificModuleCachePath,
338                                  bool Complain) override {
339       Out.indent(2) << "Header search options:\n";
340       Out.indent(4) << "System root [-isysroot=]: '" << HSOpts.Sysroot << "'\n";
341       Out.indent(4) << "Resource dir [ -resource-dir=]: '" << HSOpts.ResourceDir << "'\n";
342       Out.indent(4) << "Module Cache: '" << SpecificModuleCachePath << "'\n";
343       DUMP_BOOLEAN(HSOpts.UseBuiltinIncludes,
344                    "Use builtin include directories [-nobuiltininc]");
345       DUMP_BOOLEAN(HSOpts.UseStandardSystemIncludes,
346                    "Use standard system include directories [-nostdinc]");
347       DUMP_BOOLEAN(HSOpts.UseStandardCXXIncludes,
348                    "Use standard C++ include directories [-nostdinc++]");
349       DUMP_BOOLEAN(HSOpts.UseLibcxx,
350                    "Use libc++ (rather than libstdc++) [-stdlib=]");
351       return false;
352     }
353 
354     bool ReadPreprocessorOptions(const PreprocessorOptions &PPOpts,
355                                  bool Complain,
356                                  std::string &SuggestedPredefines) override {
357       Out.indent(2) << "Preprocessor options:\n";
358       DUMP_BOOLEAN(PPOpts.UsePredefines,
359                    "Uses compiler/target-specific predefines [-undef]");
360       DUMP_BOOLEAN(PPOpts.DetailedRecord,
361                    "Uses detailed preprocessing record (for indexing)");
362 
363       if (!PPOpts.Macros.empty()) {
364         Out.indent(4) << "Predefined macros:\n";
365       }
366 
367       for (std::vector<std::pair<std::string, bool/*isUndef*/> >::const_iterator
368              I = PPOpts.Macros.begin(), IEnd = PPOpts.Macros.end();
369            I != IEnd; ++I) {
370         Out.indent(6);
371         if (I->second)
372           Out << "-U";
373         else
374           Out << "-D";
375         Out << I->first << "\n";
376       }
377       return false;
378     }
379 
380     /// Indicates that a particular module file extension has been read.
381     void readModuleFileExtension(
382            const ModuleFileExtensionMetadata &Metadata) override {
383       Out.indent(2) << "Module file extension '"
384                     << Metadata.BlockName << "' " << Metadata.MajorVersion
385                     << "." << Metadata.MinorVersion;
386       if (!Metadata.UserInfo.empty()) {
387         Out << ": ";
388         Out.write_escaped(Metadata.UserInfo);
389       }
390 
391       Out << "\n";
392     }
393 #undef DUMP_BOOLEAN
394   };
395 }
396 
397 bool DumpModuleInfoAction::BeginInvocation(CompilerInstance &CI) {
398   // The Object file reader also supports raw ast files and there is no point in
399   // being strict about the module file format in -module-file-info mode.
400   CI.getHeaderSearchOpts().ModuleFormat = "obj";
401   return true;
402 }
403 
404 void DumpModuleInfoAction::ExecuteAction() {
405   // Set up the output file.
406   std::unique_ptr<llvm::raw_fd_ostream> OutFile;
407   StringRef OutputFileName = getCompilerInstance().getFrontendOpts().OutputFile;
408   if (!OutputFileName.empty() && OutputFileName != "-") {
409     std::error_code EC;
410     OutFile.reset(new llvm::raw_fd_ostream(OutputFileName.str(), EC,
411                                            llvm::sys::fs::F_Text));
412   }
413   llvm::raw_ostream &Out = OutFile.get()? *OutFile.get() : llvm::outs();
414 
415   Out << "Information for module file '" << getCurrentFile() << "':\n";
416   auto &FileMgr = getCompilerInstance().getFileManager();
417   auto Buffer = FileMgr.getBufferForFile(getCurrentFile());
418   StringRef Magic = (*Buffer)->getMemBufferRef().getBuffer();
419   bool IsRaw = (Magic.size() >= 4 && Magic[0] == 'C' && Magic[1] == 'P' &&
420                 Magic[2] == 'C' && Magic[3] == 'H');
421   Out << "  Module format: " << (IsRaw ? "raw" : "obj") << "\n";
422 
423   Preprocessor &PP = getCompilerInstance().getPreprocessor();
424   DumpModuleInfoListener Listener(Out);
425   HeaderSearchOptions &HSOpts =
426       PP.getHeaderSearchInfo().getHeaderSearchOpts();
427   ASTReader::readASTFileControlBlock(
428       getCurrentFile(), FileMgr, getCompilerInstance().getPCHContainerReader(),
429       /*FindModuleFileExtensions=*/true, Listener,
430       HSOpts.ModulesValidateDiagnosticOptions);
431 }
432 
433 //===----------------------------------------------------------------------===//
434 // Preprocessor Actions
435 //===----------------------------------------------------------------------===//
436 
437 void DumpRawTokensAction::ExecuteAction() {
438   Preprocessor &PP = getCompilerInstance().getPreprocessor();
439   SourceManager &SM = PP.getSourceManager();
440 
441   // Start lexing the specified input file.
442   const llvm::MemoryBuffer *FromFile = SM.getBuffer(SM.getMainFileID());
443   Lexer RawLex(SM.getMainFileID(), FromFile, SM, PP.getLangOpts());
444   RawLex.SetKeepWhitespaceMode(true);
445 
446   Token RawTok;
447   RawLex.LexFromRawLexer(RawTok);
448   while (RawTok.isNot(tok::eof)) {
449     PP.DumpToken(RawTok, true);
450     llvm::errs() << "\n";
451     RawLex.LexFromRawLexer(RawTok);
452   }
453 }
454 
455 void DumpTokensAction::ExecuteAction() {
456   Preprocessor &PP = getCompilerInstance().getPreprocessor();
457   // Start preprocessing the specified input file.
458   Token Tok;
459   PP.EnterMainSourceFile();
460   do {
461     PP.Lex(Tok);
462     PP.DumpToken(Tok, true);
463     llvm::errs() << "\n";
464   } while (Tok.isNot(tok::eof));
465 }
466 
467 void GeneratePTHAction::ExecuteAction() {
468   CompilerInstance &CI = getCompilerInstance();
469   std::unique_ptr<raw_pwrite_stream> OS =
470       CI.createDefaultOutputFile(true, getCurrentFile());
471   if (!OS)
472     return;
473 
474   CacheTokens(CI.getPreprocessor(), OS.get());
475 }
476 
477 void PreprocessOnlyAction::ExecuteAction() {
478   Preprocessor &PP = getCompilerInstance().getPreprocessor();
479 
480   // Ignore unknown pragmas.
481   PP.IgnorePragmas();
482 
483   Token Tok;
484   // Start parsing the specified input file.
485   PP.EnterMainSourceFile();
486   do {
487     PP.Lex(Tok);
488   } while (Tok.isNot(tok::eof));
489 }
490 
491 void PrintPreprocessedAction::ExecuteAction() {
492   CompilerInstance &CI = getCompilerInstance();
493   // Output file may need to be set to 'Binary', to avoid converting Unix style
494   // line feeds (<LF>) to Microsoft style line feeds (<CR><LF>).
495   //
496   // Look to see what type of line endings the file uses. If there's a
497   // CRLF, then we won't open the file up in binary mode. If there is
498   // just an LF or CR, then we will open the file up in binary mode.
499   // In this fashion, the output format should match the input format, unless
500   // the input format has inconsistent line endings.
501   //
502   // This should be a relatively fast operation since most files won't have
503   // all of their source code on a single line. However, that is still a
504   // concern, so if we scan for too long, we'll just assume the file should
505   // be opened in binary mode.
506   bool BinaryMode = true;
507   bool InvalidFile = false;
508   const SourceManager& SM = CI.getSourceManager();
509   const llvm::MemoryBuffer *Buffer = SM.getBuffer(SM.getMainFileID(),
510                                                      &InvalidFile);
511   if (!InvalidFile) {
512     const char *cur = Buffer->getBufferStart();
513     const char *end = Buffer->getBufferEnd();
514     const char *next = (cur != end) ? cur + 1 : end;
515 
516     // Limit ourselves to only scanning 256 characters into the source
517     // file.  This is mostly a sanity check in case the file has no
518     // newlines whatsoever.
519     if (end - cur > 256) end = cur + 256;
520 
521     while (next < end) {
522       if (*cur == 0x0D) {  // CR
523         if (*next == 0x0A)  // CRLF
524           BinaryMode = false;
525 
526         break;
527       } else if (*cur == 0x0A)  // LF
528         break;
529 
530       ++cur;
531       ++next;
532     }
533   }
534 
535   std::unique_ptr<raw_ostream> OS =
536       CI.createDefaultOutputFile(BinaryMode, getCurrentFile());
537   if (!OS) return;
538 
539   // If we're preprocessing a module map, start by dumping the contents of the
540   // module itself before switching to the input buffer.
541   auto &Input = getCurrentInput();
542   if (Input.getKind().getFormat() == InputKind::ModuleMap) {
543     if (Input.isFile()) {
544       (*OS) << "# 1 \"";
545       OS->write_escaped(Input.getFile());
546       (*OS) << "\"\n";
547     }
548     // FIXME: Include additional information here so that we don't need the
549     // original source files to exist on disk.
550     getCurrentModule()->print(*OS);
551     (*OS) << "#pragma clang module contents\n";
552   }
553 
554   DoPrintPreprocessedInput(CI.getPreprocessor(), OS.get(),
555                            CI.getPreprocessorOutputOpts());
556 }
557 
558 void PrintPreambleAction::ExecuteAction() {
559   switch (getCurrentFileKind().getLanguage()) {
560   case InputKind::C:
561   case InputKind::CXX:
562   case InputKind::ObjC:
563   case InputKind::ObjCXX:
564   case InputKind::OpenCL:
565   case InputKind::CUDA:
566     break;
567 
568   case InputKind::Unknown:
569   case InputKind::Asm:
570   case InputKind::LLVM_IR:
571   case InputKind::RenderScript:
572     // We can't do anything with these.
573     return;
574   }
575 
576   // We don't expect to find any #include directives in a preprocessed input.
577   if (getCurrentFileKind().isPreprocessed())
578     return;
579 
580   CompilerInstance &CI = getCompilerInstance();
581   auto Buffer = CI.getFileManager().getBufferForFile(getCurrentFile());
582   if (Buffer) {
583     unsigned Preamble =
584         Lexer::ComputePreamble((*Buffer)->getBuffer(), CI.getLangOpts()).first;
585     llvm::outs().write((*Buffer)->getBufferStart(), Preamble);
586   }
587 }
588