xref: /llvm-project/clang/lib/Frontend/FrontendAction.cpp (revision 5c0aa31c3cb448065f12ede53e4dd54a9a98f650)
1 //===--- FrontendAction.cpp -----------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "clang/Frontend/FrontendAction.h"
10 #include "clang/AST/ASTConsumer.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/AST/DeclGroup.h"
13 #include "clang/Basic/Builtins.h"
14 #include "clang/Basic/DiagnosticOptions.h"
15 #include "clang/Basic/FileEntry.h"
16 #include "clang/Basic/LangStandard.h"
17 #include "clang/Basic/Sarif.h"
18 #include "clang/Basic/Stack.h"
19 #include "clang/Frontend/ASTUnit.h"
20 #include "clang/Frontend/CompilerInstance.h"
21 #include "clang/Frontend/FrontendDiagnostic.h"
22 #include "clang/Frontend/FrontendPluginRegistry.h"
23 #include "clang/Frontend/LayoutOverrideSource.h"
24 #include "clang/Frontend/MultiplexConsumer.h"
25 #include "clang/Frontend/SARIFDiagnosticPrinter.h"
26 #include "clang/Frontend/Utils.h"
27 #include "clang/Lex/HeaderSearch.h"
28 #include "clang/Lex/LiteralSupport.h"
29 #include "clang/Lex/Preprocessor.h"
30 #include "clang/Lex/PreprocessorOptions.h"
31 #include "clang/Parse/ParseAST.h"
32 #include "clang/Sema/HLSLExternalSemaSource.h"
33 #include "clang/Sema/MultiplexExternalSemaSource.h"
34 #include "clang/Serialization/ASTDeserializationListener.h"
35 #include "clang/Serialization/ASTReader.h"
36 #include "clang/Serialization/GlobalModuleIndex.h"
37 #include "llvm/ADT/ScopeExit.h"
38 #include "llvm/Support/BuryPointer.h"
39 #include "llvm/Support/ErrorHandling.h"
40 #include "llvm/Support/FileSystem.h"
41 #include "llvm/Support/Path.h"
42 #include "llvm/Support/Timer.h"
43 #include "llvm/Support/raw_ostream.h"
44 #include <memory>
45 #include <system_error>
46 using namespace clang;
47 
48 LLVM_INSTANTIATE_REGISTRY(FrontendPluginRegistry)
49 
50 namespace {
51 
52 class DelegatingDeserializationListener : public ASTDeserializationListener {
53   ASTDeserializationListener *Previous;
54   bool DeletePrevious;
55 
56 public:
57   explicit DelegatingDeserializationListener(
58       ASTDeserializationListener *Previous, bool DeletePrevious)
59       : Previous(Previous), DeletePrevious(DeletePrevious) {}
60   ~DelegatingDeserializationListener() override {
61     if (DeletePrevious)
62       delete Previous;
63   }
64 
65   DelegatingDeserializationListener(const DelegatingDeserializationListener &) =
66       delete;
67   DelegatingDeserializationListener &
68   operator=(const DelegatingDeserializationListener &) = delete;
69 
70   void ReaderInitialized(ASTReader *Reader) override {
71     if (Previous)
72       Previous->ReaderInitialized(Reader);
73   }
74   void IdentifierRead(serialization::IdentifierID ID,
75                       IdentifierInfo *II) override {
76     if (Previous)
77       Previous->IdentifierRead(ID, II);
78   }
79   void TypeRead(serialization::TypeIdx Idx, QualType T) override {
80     if (Previous)
81       Previous->TypeRead(Idx, T);
82   }
83   void DeclRead(GlobalDeclID ID, const Decl *D) override {
84     if (Previous)
85       Previous->DeclRead(ID, D);
86   }
87   void SelectorRead(serialization::SelectorID ID, Selector Sel) override {
88     if (Previous)
89       Previous->SelectorRead(ID, Sel);
90   }
91   void MacroDefinitionRead(serialization::PreprocessedEntityID PPID,
92                            MacroDefinitionRecord *MD) override {
93     if (Previous)
94       Previous->MacroDefinitionRead(PPID, MD);
95   }
96 };
97 
98 /// Dumps deserialized declarations.
99 class DeserializedDeclsDumper : public DelegatingDeserializationListener {
100 public:
101   explicit DeserializedDeclsDumper(ASTDeserializationListener *Previous,
102                                    bool DeletePrevious)
103       : DelegatingDeserializationListener(Previous, DeletePrevious) {}
104 
105   void DeclRead(GlobalDeclID ID, const Decl *D) override {
106     llvm::outs() << "PCH DECL: " << D->getDeclKindName();
107     if (const NamedDecl *ND = dyn_cast<NamedDecl>(D)) {
108       llvm::outs() << " - ";
109       ND->printQualifiedName(llvm::outs());
110     }
111     llvm::outs() << "\n";
112 
113     DelegatingDeserializationListener::DeclRead(ID, D);
114   }
115 };
116 
117 /// Checks deserialized declarations and emits error if a name
118 /// matches one given in command-line using -error-on-deserialized-decl.
119 class DeserializedDeclsChecker : public DelegatingDeserializationListener {
120   ASTContext &Ctx;
121   std::set<std::string> NamesToCheck;
122 
123 public:
124   DeserializedDeclsChecker(ASTContext &Ctx,
125                            const std::set<std::string> &NamesToCheck,
126                            ASTDeserializationListener *Previous,
127                            bool DeletePrevious)
128       : DelegatingDeserializationListener(Previous, DeletePrevious), Ctx(Ctx),
129         NamesToCheck(NamesToCheck) {}
130 
131   void DeclRead(GlobalDeclID ID, const Decl *D) override {
132     if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
133       if (NamesToCheck.find(ND->getNameAsString()) != NamesToCheck.end()) {
134         unsigned DiagID
135           = Ctx.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error,
136                                                  "%0 was deserialized");
137         Ctx.getDiagnostics().Report(Ctx.getFullLoc(D->getLocation()), DiagID)
138             << ND;
139       }
140 
141     DelegatingDeserializationListener::DeclRead(ID, D);
142   }
143 };
144 
145 } // end anonymous namespace
146 
147 FrontendAction::FrontendAction() : Instance(nullptr) {}
148 
149 FrontendAction::~FrontendAction() {}
150 
151 void FrontendAction::setCurrentInput(const FrontendInputFile &CurrentInput,
152                                      std::unique_ptr<ASTUnit> AST) {
153   this->CurrentInput = CurrentInput;
154   CurrentASTUnit = std::move(AST);
155 }
156 
157 Module *FrontendAction::getCurrentModule() const {
158   CompilerInstance &CI = getCompilerInstance();
159   return CI.getPreprocessor().getHeaderSearchInfo().lookupModule(
160       CI.getLangOpts().CurrentModule, SourceLocation(), /*AllowSearch*/false);
161 }
162 
163 std::unique_ptr<ASTConsumer>
164 FrontendAction::CreateWrappedASTConsumer(CompilerInstance &CI,
165                                          StringRef InFile) {
166   std::unique_ptr<ASTConsumer> Consumer = CreateASTConsumer(CI, InFile);
167   if (!Consumer)
168     return nullptr;
169 
170   // Validate -add-plugin args.
171   bool FoundAllPlugins = true;
172   for (const std::string &Arg : CI.getFrontendOpts().AddPluginActions) {
173     bool Found = false;
174     for (const FrontendPluginRegistry::entry &Plugin :
175          FrontendPluginRegistry::entries()) {
176       if (Plugin.getName() == Arg)
177         Found = true;
178     }
179     if (!Found) {
180       CI.getDiagnostics().Report(diag::err_fe_invalid_plugin_name) << Arg;
181       FoundAllPlugins = false;
182     }
183   }
184   if (!FoundAllPlugins)
185     return nullptr;
186 
187   // If there are no registered plugins we don't need to wrap the consumer
188   if (FrontendPluginRegistry::begin() == FrontendPluginRegistry::end())
189     return Consumer;
190 
191   // If this is a code completion run, avoid invoking the plugin consumers
192   if (CI.hasCodeCompletionConsumer())
193     return Consumer;
194 
195   // Collect the list of plugins that go before the main action (in Consumers)
196   // or after it (in AfterConsumers)
197   std::vector<std::unique_ptr<ASTConsumer>> Consumers;
198   std::vector<std::unique_ptr<ASTConsumer>> AfterConsumers;
199   for (const FrontendPluginRegistry::entry &Plugin :
200        FrontendPluginRegistry::entries()) {
201     std::unique_ptr<PluginASTAction> P = Plugin.instantiate();
202     PluginASTAction::ActionType ActionType = P->getActionType();
203     if (ActionType == PluginASTAction::CmdlineAfterMainAction ||
204         ActionType == PluginASTAction::CmdlineBeforeMainAction) {
205       // This is O(|plugins| * |add_plugins|), but since both numbers are
206       // way below 50 in practice, that's ok.
207       if (llvm::is_contained(CI.getFrontendOpts().AddPluginActions,
208                              Plugin.getName())) {
209         if (ActionType == PluginASTAction::CmdlineBeforeMainAction)
210           ActionType = PluginASTAction::AddBeforeMainAction;
211         else
212           ActionType = PluginASTAction::AddAfterMainAction;
213       }
214     }
215     if ((ActionType == PluginASTAction::AddBeforeMainAction ||
216          ActionType == PluginASTAction::AddAfterMainAction) &&
217         P->ParseArgs(
218             CI,
219             CI.getFrontendOpts().PluginArgs[std::string(Plugin.getName())])) {
220       std::unique_ptr<ASTConsumer> PluginConsumer = P->CreateASTConsumer(CI, InFile);
221       if (ActionType == PluginASTAction::AddBeforeMainAction) {
222         Consumers.push_back(std::move(PluginConsumer));
223       } else {
224         AfterConsumers.push_back(std::move(PluginConsumer));
225       }
226     }
227   }
228 
229   // Add to Consumers the main consumer, then all the plugins that go after it
230   Consumers.push_back(std::move(Consumer));
231   if (!AfterConsumers.empty()) {
232     // If we have plugins after the main consumer, which may be the codegen
233     // action, they likely will need the ASTContext, so don't clear it in the
234     // codegen action.
235     CI.getCodeGenOpts().ClearASTBeforeBackend = false;
236     for (auto &C : AfterConsumers)
237       Consumers.push_back(std::move(C));
238   }
239 
240   return std::make_unique<MultiplexConsumer>(std::move(Consumers));
241 }
242 
243 /// For preprocessed files, if the first line is the linemarker and specifies
244 /// the original source file name, use that name as the input file name.
245 /// Returns the location of the first token after the line marker directive.
246 ///
247 /// \param CI The compiler instance.
248 /// \param InputFile Populated with the filename from the line marker.
249 /// \param IsModuleMap If \c true, add a line note corresponding to this line
250 ///        directive. (We need to do this because the directive will not be
251 ///        visited by the preprocessor.)
252 static SourceLocation ReadOriginalFileName(CompilerInstance &CI,
253                                            std::string &InputFile,
254                                            bool IsModuleMap = false) {
255   auto &SourceMgr = CI.getSourceManager();
256   auto MainFileID = SourceMgr.getMainFileID();
257 
258   auto MainFileBuf = SourceMgr.getBufferOrNone(MainFileID);
259   if (!MainFileBuf)
260     return SourceLocation();
261 
262   std::unique_ptr<Lexer> RawLexer(
263       new Lexer(MainFileID, *MainFileBuf, SourceMgr, CI.getLangOpts()));
264 
265   // If the first line has the syntax of
266   //
267   // # NUM "FILENAME"
268   //
269   // we use FILENAME as the input file name.
270   Token T;
271   if (RawLexer->LexFromRawLexer(T) || T.getKind() != tok::hash)
272     return SourceLocation();
273   if (RawLexer->LexFromRawLexer(T) || T.isAtStartOfLine() ||
274       T.getKind() != tok::numeric_constant)
275     return SourceLocation();
276 
277   unsigned LineNo;
278   SourceLocation LineNoLoc = T.getLocation();
279   if (IsModuleMap) {
280     llvm::SmallString<16> Buffer;
281     if (Lexer::getSpelling(LineNoLoc, Buffer, SourceMgr, CI.getLangOpts())
282             .getAsInteger(10, LineNo))
283       return SourceLocation();
284   }
285 
286   RawLexer->LexFromRawLexer(T);
287   if (T.isAtStartOfLine() || T.getKind() != tok::string_literal)
288     return SourceLocation();
289 
290   StringLiteralParser Literal(T, CI.getPreprocessor());
291   if (Literal.hadError)
292     return SourceLocation();
293   RawLexer->LexFromRawLexer(T);
294   if (T.isNot(tok::eof) && !T.isAtStartOfLine())
295     return SourceLocation();
296   InputFile = Literal.GetString().str();
297 
298   if (IsModuleMap)
299     CI.getSourceManager().AddLineNote(
300         LineNoLoc, LineNo, SourceMgr.getLineTableFilenameID(InputFile), false,
301         false, SrcMgr::C_User_ModuleMap);
302 
303   return T.getLocation();
304 }
305 
306 static SmallVectorImpl<char> &
307 operator+=(SmallVectorImpl<char> &Includes, StringRef RHS) {
308   Includes.append(RHS.begin(), RHS.end());
309   return Includes;
310 }
311 
312 static void addHeaderInclude(StringRef HeaderName,
313                              SmallVectorImpl<char> &Includes,
314                              const LangOptions &LangOpts,
315                              bool IsExternC) {
316   if (IsExternC && LangOpts.CPlusPlus)
317     Includes += "extern \"C\" {\n";
318   if (LangOpts.ObjC)
319     Includes += "#import \"";
320   else
321     Includes += "#include \"";
322 
323   Includes += HeaderName;
324 
325   Includes += "\"\n";
326   if (IsExternC && LangOpts.CPlusPlus)
327     Includes += "}\n";
328 }
329 
330 /// Collect the set of header includes needed to construct the given
331 /// module and update the TopHeaders file set of the module.
332 ///
333 /// \param Module The module we're collecting includes from.
334 ///
335 /// \param Includes Will be augmented with the set of \#includes or \#imports
336 /// needed to load all of the named headers.
337 static std::error_code collectModuleHeaderIncludes(
338     const LangOptions &LangOpts, FileManager &FileMgr, DiagnosticsEngine &Diag,
339     ModuleMap &ModMap, clang::Module *Module, SmallVectorImpl<char> &Includes) {
340   // Don't collect any headers for unavailable modules.
341   if (!Module->isAvailable())
342     return std::error_code();
343 
344   // Resolve all lazy header directives to header files.
345   ModMap.resolveHeaderDirectives(Module, /*File=*/std::nullopt);
346 
347   // If any headers are missing, we can't build this module. In most cases,
348   // diagnostics for this should have already been produced; we only get here
349   // if explicit stat information was provided.
350   // FIXME: If the name resolves to a file with different stat information,
351   // produce a better diagnostic.
352   if (!Module->MissingHeaders.empty()) {
353     auto &MissingHeader = Module->MissingHeaders.front();
354     Diag.Report(MissingHeader.FileNameLoc, diag::err_module_header_missing)
355       << MissingHeader.IsUmbrella << MissingHeader.FileName;
356     return std::error_code();
357   }
358 
359   // Add includes for each of these headers.
360   for (auto HK : {Module::HK_Normal, Module::HK_Private}) {
361     for (const Module::Header &H : Module->getHeaders(HK)) {
362       Module->addTopHeader(H.Entry);
363       // Use the path as specified in the module map file. We'll look for this
364       // file relative to the module build directory (the directory containing
365       // the module map file) so this will find the same file that we found
366       // while parsing the module map.
367       addHeaderInclude(H.PathRelativeToRootModuleDirectory, Includes, LangOpts,
368                        Module->IsExternC);
369     }
370   }
371   // Note that Module->PrivateHeaders will not be a TopHeader.
372 
373   if (std::optional<Module::Header> UmbrellaHeader =
374           Module->getUmbrellaHeaderAsWritten()) {
375     Module->addTopHeader(UmbrellaHeader->Entry);
376     if (Module->Parent)
377       // Include the umbrella header for submodules.
378       addHeaderInclude(UmbrellaHeader->PathRelativeToRootModuleDirectory,
379                        Includes, LangOpts, Module->IsExternC);
380   } else if (std::optional<Module::DirectoryName> UmbrellaDir =
381                  Module->getUmbrellaDirAsWritten()) {
382     // Add all of the headers we find in this subdirectory.
383     std::error_code EC;
384     SmallString<128> DirNative;
385     llvm::sys::path::native(UmbrellaDir->Entry.getName(), DirNative);
386 
387     llvm::vfs::FileSystem &FS = FileMgr.getVirtualFileSystem();
388     SmallVector<std::pair<std::string, FileEntryRef>, 8> Headers;
389     for (llvm::vfs::recursive_directory_iterator Dir(FS, DirNative, EC), End;
390          Dir != End && !EC; Dir.increment(EC)) {
391       // Check whether this entry has an extension typically associated with
392       // headers.
393       if (!llvm::StringSwitch<bool>(llvm::sys::path::extension(Dir->path()))
394                .Cases(".h", ".H", ".hh", ".hpp", true)
395                .Default(false))
396         continue;
397 
398       auto Header = FileMgr.getOptionalFileRef(Dir->path());
399       // FIXME: This shouldn't happen unless there is a file system race. Is
400       // that worth diagnosing?
401       if (!Header)
402         continue;
403 
404       // If this header is marked 'unavailable' in this module, don't include
405       // it.
406       if (ModMap.isHeaderUnavailableInModule(*Header, Module))
407         continue;
408 
409       // Compute the relative path from the directory to this file.
410       SmallVector<StringRef, 16> Components;
411       auto PathIt = llvm::sys::path::rbegin(Dir->path());
412       for (int I = 0; I != Dir.level() + 1; ++I, ++PathIt)
413         Components.push_back(*PathIt);
414       SmallString<128> RelativeHeader(
415           UmbrellaDir->PathRelativeToRootModuleDirectory);
416       for (auto It = Components.rbegin(), End = Components.rend(); It != End;
417            ++It)
418         llvm::sys::path::append(RelativeHeader, *It);
419 
420       std::string RelName = RelativeHeader.c_str();
421       Headers.push_back(std::make_pair(RelName, *Header));
422     }
423 
424     if (EC)
425       return EC;
426 
427     // Sort header paths and make the header inclusion order deterministic
428     // across different OSs and filesystems.
429     llvm::sort(Headers, llvm::less_first());
430     for (auto &H : Headers) {
431       // Include this header as part of the umbrella directory.
432       Module->addTopHeader(H.second);
433       addHeaderInclude(H.first, Includes, LangOpts, Module->IsExternC);
434     }
435   }
436 
437   // Recurse into submodules.
438   for (auto *Submodule : Module->submodules())
439     if (std::error_code Err = collectModuleHeaderIncludes(
440             LangOpts, FileMgr, Diag, ModMap, Submodule, Includes))
441       return Err;
442 
443   return std::error_code();
444 }
445 
446 static bool loadModuleMapForModuleBuild(CompilerInstance &CI, bool IsSystem,
447                                         bool IsPreprocessed,
448                                         std::string &PresumedModuleMapFile,
449                                         unsigned &Offset) {
450   auto &SrcMgr = CI.getSourceManager();
451   HeaderSearch &HS = CI.getPreprocessor().getHeaderSearchInfo();
452 
453   // Map the current input to a file.
454   FileID ModuleMapID = SrcMgr.getMainFileID();
455   OptionalFileEntryRef ModuleMap = SrcMgr.getFileEntryRefForID(ModuleMapID);
456   assert(ModuleMap && "MainFileID without FileEntry");
457 
458   // If the module map is preprocessed, handle the initial line marker;
459   // line directives are not part of the module map syntax in general.
460   Offset = 0;
461   if (IsPreprocessed) {
462     SourceLocation EndOfLineMarker =
463         ReadOriginalFileName(CI, PresumedModuleMapFile, /*IsModuleMap*/ true);
464     if (EndOfLineMarker.isValid())
465       Offset = CI.getSourceManager().getDecomposedLoc(EndOfLineMarker).second;
466   }
467 
468   // Load the module map file.
469   if (HS.loadModuleMapFile(*ModuleMap, IsSystem, ModuleMapID, &Offset,
470                            PresumedModuleMapFile))
471     return true;
472 
473   if (SrcMgr.getBufferOrFake(ModuleMapID).getBufferSize() == Offset)
474     Offset = 0;
475 
476   // Infer framework module if possible.
477   if (HS.getModuleMap().canInferFrameworkModule(ModuleMap->getDir())) {
478     SmallString<128> InferredFrameworkPath = ModuleMap->getDir().getName();
479     llvm::sys::path::append(InferredFrameworkPath,
480                             CI.getLangOpts().ModuleName + ".framework");
481     if (auto Dir =
482             CI.getFileManager().getOptionalDirectoryRef(InferredFrameworkPath))
483       (void)HS.getModuleMap().inferFrameworkModule(*Dir, IsSystem, nullptr);
484   }
485 
486   return false;
487 }
488 
489 static Module *prepareToBuildModule(CompilerInstance &CI,
490                                     StringRef ModuleMapFilename) {
491   if (CI.getLangOpts().CurrentModule.empty()) {
492     CI.getDiagnostics().Report(diag::err_missing_module_name);
493 
494     // FIXME: Eventually, we could consider asking whether there was just
495     // a single module described in the module map, and use that as a
496     // default. Then it would be fairly trivial to just "compile" a module
497     // map with a single module (the common case).
498     return nullptr;
499   }
500 
501   // Dig out the module definition.
502   HeaderSearch &HS = CI.getPreprocessor().getHeaderSearchInfo();
503   Module *M = HS.lookupModule(CI.getLangOpts().CurrentModule, SourceLocation(),
504                               /*AllowSearch=*/true);
505   if (!M) {
506     CI.getDiagnostics().Report(diag::err_missing_module)
507       << CI.getLangOpts().CurrentModule << ModuleMapFilename;
508 
509     return nullptr;
510   }
511 
512   // Check whether we can build this module at all.
513   if (Preprocessor::checkModuleIsAvailable(CI.getLangOpts(), CI.getTarget(), *M,
514                                            CI.getDiagnostics()))
515     return nullptr;
516 
517   // Inform the preprocessor that includes from within the input buffer should
518   // be resolved relative to the build directory of the module map file.
519   CI.getPreprocessor().setMainFileDir(*M->Directory);
520 
521   // If the module was inferred from a different module map (via an expanded
522   // umbrella module definition), track that fact.
523   // FIXME: It would be preferable to fill this in as part of processing
524   // the module map, rather than adding it after the fact.
525   StringRef OriginalModuleMapName = CI.getFrontendOpts().OriginalModuleMap;
526   if (!OriginalModuleMapName.empty()) {
527     auto OriginalModuleMap =
528         CI.getFileManager().getOptionalFileRef(OriginalModuleMapName,
529                                                /*openFile*/ true);
530     if (!OriginalModuleMap) {
531       CI.getDiagnostics().Report(diag::err_module_map_not_found)
532         << OriginalModuleMapName;
533       return nullptr;
534     }
535     if (*OriginalModuleMap != CI.getSourceManager().getFileEntryRefForID(
536                                   CI.getSourceManager().getMainFileID())) {
537       auto FileCharacter =
538           M->IsSystem ? SrcMgr::C_System_ModuleMap : SrcMgr::C_User_ModuleMap;
539       FileID OriginalModuleMapFID = CI.getSourceManager().getOrCreateFileID(
540           *OriginalModuleMap, FileCharacter);
541       CI.getPreprocessor()
542           .getHeaderSearchInfo()
543           .getModuleMap()
544           .setInferredModuleAllowedBy(M, OriginalModuleMapFID);
545     }
546   }
547 
548   // If we're being run from the command-line, the module build stack will not
549   // have been filled in yet, so complete it now in order to allow us to detect
550   // module cycles.
551   SourceManager &SourceMgr = CI.getSourceManager();
552   if (SourceMgr.getModuleBuildStack().empty())
553     SourceMgr.pushModuleBuildStack(CI.getLangOpts().CurrentModule,
554                                    FullSourceLoc(SourceLocation(), SourceMgr));
555   return M;
556 }
557 
558 /// Compute the input buffer that should be used to build the specified module.
559 static std::unique_ptr<llvm::MemoryBuffer>
560 getInputBufferForModule(CompilerInstance &CI, Module *M) {
561   FileManager &FileMgr = CI.getFileManager();
562 
563   // Collect the set of #includes we need to build the module.
564   SmallString<256> HeaderContents;
565   std::error_code Err = std::error_code();
566   if (std::optional<Module::Header> UmbrellaHeader =
567           M->getUmbrellaHeaderAsWritten())
568     addHeaderInclude(UmbrellaHeader->PathRelativeToRootModuleDirectory,
569                      HeaderContents, CI.getLangOpts(), M->IsExternC);
570   Err = collectModuleHeaderIncludes(
571       CI.getLangOpts(), FileMgr, CI.getDiagnostics(),
572       CI.getPreprocessor().getHeaderSearchInfo().getModuleMap(), M,
573       HeaderContents);
574 
575   if (Err) {
576     CI.getDiagnostics().Report(diag::err_module_cannot_create_includes)
577       << M->getFullModuleName() << Err.message();
578     return nullptr;
579   }
580 
581   return llvm::MemoryBuffer::getMemBufferCopy(
582       HeaderContents, Module::getModuleInputBufferName());
583 }
584 
585 bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
586                                      const FrontendInputFile &RealInput) {
587   FrontendInputFile Input(RealInput);
588   assert(!Instance && "Already processing a source file!");
589   assert(!Input.isEmpty() && "Unexpected empty filename!");
590   setCurrentInput(Input);
591   setCompilerInstance(&CI);
592 
593   bool HasBegunSourceFile = false;
594   bool ReplayASTFile = Input.getKind().getFormat() == InputKind::Precompiled &&
595                        usesPreprocessorOnly();
596 
597   // If we fail, reset state since the client will not end up calling the
598   // matching EndSourceFile(). All paths that return true should release this.
599   auto FailureCleanup = llvm::make_scope_exit([&]() {
600     if (HasBegunSourceFile)
601       CI.getDiagnosticClient().EndSourceFile();
602     CI.setASTConsumer(nullptr);
603     CI.clearOutputFiles(/*EraseFiles=*/true);
604     CI.getLangOpts().setCompilingModule(LangOptions::CMK_None);
605     setCurrentInput(FrontendInputFile());
606     setCompilerInstance(nullptr);
607   });
608 
609   if (!BeginInvocation(CI))
610     return false;
611 
612   // If we're replaying the build of an AST file, import it and set up
613   // the initial state from its build.
614   if (ReplayASTFile) {
615     IntrusiveRefCntPtr<DiagnosticsEngine> Diags(&CI.getDiagnostics());
616 
617     // The AST unit populates its own diagnostics engine rather than ours.
618     IntrusiveRefCntPtr<DiagnosticsEngine> ASTDiags(
619         new DiagnosticsEngine(Diags->getDiagnosticIDs(),
620                               &Diags->getDiagnosticOptions()));
621     ASTDiags->setClient(Diags->getClient(), /*OwnsClient*/false);
622 
623     // FIXME: What if the input is a memory buffer?
624     StringRef InputFile = Input.getFile();
625 
626     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromASTFile(
627         InputFile, CI.getPCHContainerReader(), ASTUnit::LoadPreprocessorOnly,
628         ASTDiags, CI.getFileSystemOpts(),
629         /*HeaderSearchOptions=*/nullptr);
630     if (!AST)
631       return false;
632 
633     // Options relating to how we treat the input (but not what we do with it)
634     // are inherited from the AST unit.
635     CI.getHeaderSearchOpts() = AST->getHeaderSearchOpts();
636     CI.getPreprocessorOpts() = AST->getPreprocessorOpts();
637     CI.getLangOpts() = AST->getLangOpts();
638 
639     // Set the shared objects, these are reset when we finish processing the
640     // file, otherwise the CompilerInstance will happily destroy them.
641     CI.setFileManager(&AST->getFileManager());
642     CI.createSourceManager(CI.getFileManager());
643     CI.getSourceManager().initializeForReplay(AST->getSourceManager());
644 
645     // Preload all the module files loaded transitively by the AST unit. Also
646     // load all module map files that were parsed as part of building the AST
647     // unit.
648     if (auto ASTReader = AST->getASTReader()) {
649       auto &MM = ASTReader->getModuleManager();
650       auto &PrimaryModule = MM.getPrimaryModule();
651 
652       for (serialization::ModuleFile &MF : MM)
653         if (&MF != &PrimaryModule)
654           CI.getFrontendOpts().ModuleFiles.push_back(MF.FileName);
655 
656       ASTReader->visitTopLevelModuleMaps(PrimaryModule, [&](FileEntryRef FE) {
657         CI.getFrontendOpts().ModuleMapFiles.push_back(
658             std::string(FE.getName()));
659       });
660     }
661 
662     // Set up the input file for replay purposes.
663     auto Kind = AST->getInputKind();
664     if (Kind.getFormat() == InputKind::ModuleMap) {
665       Module *ASTModule =
666           AST->getPreprocessor().getHeaderSearchInfo().lookupModule(
667               AST->getLangOpts().CurrentModule, SourceLocation(),
668               /*AllowSearch*/ false);
669       assert(ASTModule && "module file does not define its own module");
670       Input = FrontendInputFile(ASTModule->PresumedModuleMapFile, Kind);
671     } else {
672       auto &OldSM = AST->getSourceManager();
673       FileID ID = OldSM.getMainFileID();
674       if (auto File = OldSM.getFileEntryRefForID(ID))
675         Input = FrontendInputFile(File->getName(), Kind);
676       else
677         Input = FrontendInputFile(OldSM.getBufferOrFake(ID), Kind);
678     }
679     setCurrentInput(Input, std::move(AST));
680   }
681 
682   // AST files follow a very different path, since they share objects via the
683   // AST unit.
684   if (Input.getKind().getFormat() == InputKind::Precompiled) {
685     assert(!usesPreprocessorOnly() && "this case was handled above");
686     assert(hasASTFileSupport() &&
687            "This action does not have AST file support!");
688 
689     IntrusiveRefCntPtr<DiagnosticsEngine> Diags(&CI.getDiagnostics());
690 
691     // FIXME: What if the input is a memory buffer?
692     StringRef InputFile = Input.getFile();
693 
694     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromASTFile(
695         InputFile, CI.getPCHContainerReader(), ASTUnit::LoadEverything, Diags,
696         CI.getFileSystemOpts(), CI.getHeaderSearchOptsPtr(),
697         CI.getLangOptsPtr());
698 
699     if (!AST)
700       return false;
701 
702     // Inform the diagnostic client we are processing a source file.
703     CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(), nullptr);
704     HasBegunSourceFile = true;
705 
706     // Set the shared objects, these are reset when we finish processing the
707     // file, otherwise the CompilerInstance will happily destroy them.
708     CI.setFileManager(&AST->getFileManager());
709     CI.setSourceManager(&AST->getSourceManager());
710     CI.setPreprocessor(AST->getPreprocessorPtr());
711     Preprocessor &PP = CI.getPreprocessor();
712     PP.getBuiltinInfo().initializeBuiltins(PP.getIdentifierTable(),
713                                            PP.getLangOpts());
714     CI.setASTContext(&AST->getASTContext());
715 
716     setCurrentInput(Input, std::move(AST));
717 
718     // Initialize the action.
719     if (!BeginSourceFileAction(CI))
720       return false;
721 
722     // Create the AST consumer.
723     CI.setASTConsumer(CreateWrappedASTConsumer(CI, InputFile));
724     if (!CI.hasASTConsumer())
725       return false;
726 
727     FailureCleanup.release();
728     return true;
729   }
730 
731   // Set up the file and source managers, if needed.
732   if (!CI.hasFileManager()) {
733     if (!CI.createFileManager()) {
734       return false;
735     }
736   }
737   if (!CI.hasSourceManager()) {
738     CI.createSourceManager(CI.getFileManager());
739     if (CI.getDiagnosticOpts().getFormat() == DiagnosticOptions::SARIF) {
740       static_cast<SARIFDiagnosticPrinter *>(&CI.getDiagnosticClient())
741           ->setSarifWriter(
742               std::make_unique<SarifDocumentWriter>(CI.getSourceManager()));
743     }
744   }
745 
746   // Set up embedding for any specified files. Do this before we load any
747   // source files, including the primary module map for the compilation.
748   for (const auto &F : CI.getFrontendOpts().ModulesEmbedFiles) {
749     if (auto FE = CI.getFileManager().getOptionalFileRef(F, /*openFile*/true))
750       CI.getSourceManager().setFileIsTransient(*FE);
751     else
752       CI.getDiagnostics().Report(diag::err_modules_embed_file_not_found) << F;
753   }
754   if (CI.getFrontendOpts().ModulesEmbedAllFiles)
755     CI.getSourceManager().setAllFilesAreTransient(true);
756 
757   // IR files bypass the rest of initialization.
758   if (Input.getKind().getLanguage() == Language::LLVM_IR) {
759     if (!hasIRSupport()) {
760       CI.getDiagnostics().Report(diag::err_ast_action_on_llvm_ir)
761           << Input.getFile();
762       return false;
763     }
764 
765     // Inform the diagnostic client we are processing a source file.
766     CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(), nullptr);
767     HasBegunSourceFile = true;
768 
769     // Initialize the action.
770     if (!BeginSourceFileAction(CI))
771       return false;
772 
773     // Initialize the main file entry.
774     if (!CI.InitializeSourceManager(CurrentInput))
775       return false;
776 
777     FailureCleanup.release();
778     return true;
779   }
780 
781   // If the implicit PCH include is actually a directory, rather than
782   // a single file, search for a suitable PCH file in that directory.
783   if (!CI.getPreprocessorOpts().ImplicitPCHInclude.empty()) {
784     FileManager &FileMgr = CI.getFileManager();
785     PreprocessorOptions &PPOpts = CI.getPreprocessorOpts();
786     StringRef PCHInclude = PPOpts.ImplicitPCHInclude;
787     std::string SpecificModuleCachePath = CI.getSpecificModuleCachePath();
788     if (auto PCHDir = FileMgr.getOptionalDirectoryRef(PCHInclude)) {
789       std::error_code EC;
790       SmallString<128> DirNative;
791       llvm::sys::path::native(PCHDir->getName(), DirNative);
792       bool Found = false;
793       llvm::vfs::FileSystem &FS = FileMgr.getVirtualFileSystem();
794       for (llvm::vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC),
795                                          DirEnd;
796            Dir != DirEnd && !EC; Dir.increment(EC)) {
797         // Check whether this is an acceptable AST file.
798         if (ASTReader::isAcceptableASTFile(
799                 Dir->path(), FileMgr, CI.getModuleCache(),
800                 CI.getPCHContainerReader(), CI.getLangOpts(),
801                 CI.getTargetOpts(), CI.getPreprocessorOpts(),
802                 SpecificModuleCachePath, /*RequireStrictOptionMatches=*/true)) {
803           PPOpts.ImplicitPCHInclude = std::string(Dir->path());
804           Found = true;
805           break;
806         }
807       }
808 
809       if (!Found) {
810         CI.getDiagnostics().Report(diag::err_fe_no_pch_in_dir) << PCHInclude;
811         return false;
812       }
813     }
814   }
815 
816   // Set up the preprocessor if needed. When parsing model files the
817   // preprocessor of the original source is reused.
818   if (!isModelParsingAction())
819     CI.createPreprocessor(getTranslationUnitKind());
820 
821   // Inform the diagnostic client we are processing a source file.
822   CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(),
823                                            &CI.getPreprocessor());
824   HasBegunSourceFile = true;
825 
826   // Handle C++20 header units.
827   // Here, the user has the option to specify that the header name should be
828   // looked up in the pre-processor search paths (and the main filename as
829   // passed by the driver might therefore be incomplete until that look-up).
830   if (CI.getLangOpts().CPlusPlusModules && Input.getKind().isHeaderUnit() &&
831       !Input.getKind().isPreprocessed()) {
832     StringRef FileName = Input.getFile();
833     InputKind Kind = Input.getKind();
834     if (Kind.getHeaderUnitKind() != InputKind::HeaderUnit_Abs) {
835       assert(CI.hasPreprocessor() &&
836              "trying to build a header unit without a Pre-processor?");
837       HeaderSearch &HS = CI.getPreprocessor().getHeaderSearchInfo();
838       // Relative searches begin from CWD.
839       auto Dir = CI.getFileManager().getOptionalDirectoryRef(".");
840       SmallVector<std::pair<OptionalFileEntryRef, DirectoryEntryRef>, 1> CWD;
841       CWD.push_back({std::nullopt, *Dir});
842       OptionalFileEntryRef FE =
843           HS.LookupFile(FileName, SourceLocation(),
844                         /*Angled*/ Input.getKind().getHeaderUnitKind() ==
845                             InputKind::HeaderUnit_System,
846                         nullptr, nullptr, CWD, nullptr, nullptr, nullptr,
847                         nullptr, nullptr, nullptr);
848       if (!FE) {
849         CI.getDiagnostics().Report(diag::err_module_header_file_not_found)
850             << FileName;
851         return false;
852       }
853       // We now have the filename...
854       FileName = FE->getName();
855       // ... still a header unit, but now use the path as written.
856       Kind = Input.getKind().withHeaderUnit(InputKind::HeaderUnit_Abs);
857       Input = FrontendInputFile(FileName, Kind, Input.isSystem());
858     }
859     // Unless the user has overridden the name, the header unit module name is
860     // the pathname for the file.
861     if (CI.getLangOpts().ModuleName.empty())
862       CI.getLangOpts().ModuleName = std::string(FileName);
863     CI.getLangOpts().CurrentModule = CI.getLangOpts().ModuleName;
864   }
865 
866   if (!CI.InitializeSourceManager(Input))
867     return false;
868 
869   if (CI.getLangOpts().CPlusPlusModules && Input.getKind().isHeaderUnit() &&
870       Input.getKind().isPreprocessed() && !usesPreprocessorOnly()) {
871     // We have an input filename like foo.iih, but we want to find the right
872     // module name (and original file, to build the map entry).
873     // Check if the first line specifies the original source file name with a
874     // linemarker.
875     std::string PresumedInputFile = std::string(getCurrentFileOrBufferName());
876     ReadOriginalFileName(CI, PresumedInputFile);
877     // Unless the user overrides this, the module name is the name by which the
878     // original file was known.
879     if (CI.getLangOpts().ModuleName.empty())
880       CI.getLangOpts().ModuleName = std::string(PresumedInputFile);
881     CI.getLangOpts().CurrentModule = CI.getLangOpts().ModuleName;
882   }
883 
884   // For module map files, we first parse the module map and synthesize a
885   // "<module-includes>" buffer before more conventional processing.
886   if (Input.getKind().getFormat() == InputKind::ModuleMap) {
887     CI.getLangOpts().setCompilingModule(LangOptions::CMK_ModuleMap);
888 
889     std::string PresumedModuleMapFile;
890     unsigned OffsetToContents;
891     if (loadModuleMapForModuleBuild(CI, Input.isSystem(),
892                                     Input.isPreprocessed(),
893                                     PresumedModuleMapFile, OffsetToContents))
894       return false;
895 
896     auto *CurrentModule = prepareToBuildModule(CI, Input.getFile());
897     if (!CurrentModule)
898       return false;
899 
900     CurrentModule->PresumedModuleMapFile = PresumedModuleMapFile;
901 
902     if (OffsetToContents)
903       // If the module contents are in the same file, skip to them.
904       CI.getPreprocessor().setSkipMainFilePreamble(OffsetToContents, true);
905     else {
906       // Otherwise, convert the module description to a suitable input buffer.
907       auto Buffer = getInputBufferForModule(CI, CurrentModule);
908       if (!Buffer)
909         return false;
910 
911       // Reinitialize the main file entry to refer to the new input.
912       auto Kind = CurrentModule->IsSystem ? SrcMgr::C_System : SrcMgr::C_User;
913       auto &SourceMgr = CI.getSourceManager();
914       auto BufferID = SourceMgr.createFileID(std::move(Buffer), Kind);
915       assert(BufferID.isValid() && "couldn't create module buffer ID");
916       SourceMgr.setMainFileID(BufferID);
917     }
918   }
919 
920   // Initialize the action.
921   if (!BeginSourceFileAction(CI))
922     return false;
923 
924   // If we were asked to load any module map files, do so now.
925   for (const auto &Filename : CI.getFrontendOpts().ModuleMapFiles) {
926     if (auto File = CI.getFileManager().getOptionalFileRef(Filename))
927       CI.getPreprocessor().getHeaderSearchInfo().loadModuleMapFile(
928           *File, /*IsSystem*/false);
929     else
930       CI.getDiagnostics().Report(diag::err_module_map_not_found) << Filename;
931   }
932 
933   // If compiling implementation of a module, load its module map file now.
934   (void)CI.getPreprocessor().getCurrentModuleImplementation();
935 
936   // Add a module declaration scope so that modules from -fmodule-map-file
937   // arguments may shadow modules found implicitly in search paths.
938   CI.getPreprocessor()
939       .getHeaderSearchInfo()
940       .getModuleMap()
941       .finishModuleDeclarationScope();
942 
943   // Create the AST context and consumer unless this is a preprocessor only
944   // action.
945   if (!usesPreprocessorOnly()) {
946     // Parsing a model file should reuse the existing ASTContext.
947     if (!isModelParsingAction())
948       CI.createASTContext();
949 
950     // For preprocessed files, check if the first line specifies the original
951     // source file name with a linemarker.
952     std::string PresumedInputFile = std::string(getCurrentFileOrBufferName());
953     if (Input.isPreprocessed())
954       ReadOriginalFileName(CI, PresumedInputFile);
955 
956     std::unique_ptr<ASTConsumer> Consumer =
957         CreateWrappedASTConsumer(CI, PresumedInputFile);
958     if (!Consumer)
959       return false;
960 
961     // FIXME: should not overwrite ASTMutationListener when parsing model files?
962     if (!isModelParsingAction())
963       CI.getASTContext().setASTMutationListener(Consumer->GetASTMutationListener());
964 
965     if (!CI.getPreprocessorOpts().ChainedIncludes.empty()) {
966       // Convert headers to PCH and chain them.
967       IntrusiveRefCntPtr<ExternalSemaSource> source, FinalReader;
968       source = createChainedIncludesSource(CI, FinalReader);
969       if (!source)
970         return false;
971       CI.setASTReader(static_cast<ASTReader *>(FinalReader.get()));
972       CI.getASTContext().setExternalSource(source);
973     } else if (CI.getLangOpts().Modules ||
974                !CI.getPreprocessorOpts().ImplicitPCHInclude.empty()) {
975       // Use PCM or PCH.
976       assert(hasPCHSupport() && "This action does not have PCH support!");
977       ASTDeserializationListener *DeserialListener =
978           Consumer->GetASTDeserializationListener();
979       bool DeleteDeserialListener = false;
980       if (CI.getPreprocessorOpts().DumpDeserializedPCHDecls) {
981         DeserialListener = new DeserializedDeclsDumper(DeserialListener,
982                                                        DeleteDeserialListener);
983         DeleteDeserialListener = true;
984       }
985       if (!CI.getPreprocessorOpts().DeserializedPCHDeclsToErrorOn.empty()) {
986         DeserialListener = new DeserializedDeclsChecker(
987             CI.getASTContext(),
988             CI.getPreprocessorOpts().DeserializedPCHDeclsToErrorOn,
989             DeserialListener, DeleteDeserialListener);
990         DeleteDeserialListener = true;
991       }
992       if (!CI.getPreprocessorOpts().ImplicitPCHInclude.empty()) {
993         CI.createPCHExternalASTSource(
994             CI.getPreprocessorOpts().ImplicitPCHInclude,
995             CI.getPreprocessorOpts().DisablePCHOrModuleValidation,
996             CI.getPreprocessorOpts().AllowPCHWithCompilerErrors,
997             DeserialListener, DeleteDeserialListener);
998         if (!CI.getASTContext().getExternalSource())
999           return false;
1000       }
1001       // If modules are enabled, create the AST reader before creating
1002       // any builtins, so that all declarations know that they might be
1003       // extended by an external source.
1004       if (CI.getLangOpts().Modules || !CI.hasASTContext() ||
1005           !CI.getASTContext().getExternalSource()) {
1006         CI.createASTReader();
1007         CI.getASTReader()->setDeserializationListener(DeserialListener,
1008                                                       DeleteDeserialListener);
1009       }
1010     }
1011 
1012     CI.setASTConsumer(std::move(Consumer));
1013     if (!CI.hasASTConsumer())
1014       return false;
1015   }
1016 
1017   // Initialize built-in info as long as we aren't using an external AST
1018   // source.
1019   if (CI.getLangOpts().Modules || !CI.hasASTContext() ||
1020       !CI.getASTContext().getExternalSource()) {
1021     Preprocessor &PP = CI.getPreprocessor();
1022     PP.getBuiltinInfo().initializeBuiltins(PP.getIdentifierTable(),
1023                                            PP.getLangOpts());
1024   } else {
1025     // FIXME: If this is a problem, recover from it by creating a multiplex
1026     // source.
1027     assert((!CI.getLangOpts().Modules || CI.getASTReader()) &&
1028            "modules enabled but created an external source that "
1029            "doesn't support modules");
1030   }
1031 
1032   // If we were asked to load any module files, do so now.
1033   for (const auto &ModuleFile : CI.getFrontendOpts().ModuleFiles) {
1034     serialization::ModuleFile *Loaded = nullptr;
1035     if (!CI.loadModuleFile(ModuleFile, Loaded))
1036       return false;
1037 
1038     if (Loaded && Loaded->StandardCXXModule)
1039       CI.getDiagnostics().Report(
1040           diag::warn_eagerly_load_for_standard_cplusplus_modules);
1041   }
1042 
1043   // If there is a layout overrides file, attach an external AST source that
1044   // provides the layouts from that file.
1045   if (!CI.getFrontendOpts().OverrideRecordLayoutsFile.empty() &&
1046       CI.hasASTContext() && !CI.getASTContext().getExternalSource()) {
1047     IntrusiveRefCntPtr<ExternalASTSource>
1048       Override(new LayoutOverrideSource(
1049                      CI.getFrontendOpts().OverrideRecordLayoutsFile));
1050     CI.getASTContext().setExternalSource(Override);
1051   }
1052 
1053   // Setup HLSL External Sema Source
1054   if (CI.getLangOpts().HLSL && CI.hasASTContext()) {
1055     IntrusiveRefCntPtr<ExternalSemaSource> HLSLSema(
1056         new HLSLExternalSemaSource());
1057     if (auto *SemaSource = dyn_cast_if_present<ExternalSemaSource>(
1058             CI.getASTContext().getExternalSource())) {
1059       IntrusiveRefCntPtr<ExternalSemaSource> MultiSema(
1060           new MultiplexExternalSemaSource(SemaSource, HLSLSema.get()));
1061       CI.getASTContext().setExternalSource(MultiSema);
1062     } else
1063       CI.getASTContext().setExternalSource(HLSLSema);
1064   }
1065 
1066   FailureCleanup.release();
1067   return true;
1068 }
1069 
1070 llvm::Error FrontendAction::Execute() {
1071   CompilerInstance &CI = getCompilerInstance();
1072   ExecuteAction();
1073 
1074   // If we are supposed to rebuild the global module index, do so now unless
1075   // there were any module-build failures.
1076   if (CI.shouldBuildGlobalModuleIndex() && CI.hasFileManager() &&
1077       CI.hasPreprocessor()) {
1078     StringRef Cache =
1079         CI.getPreprocessor().getHeaderSearchInfo().getModuleCachePath();
1080     if (!Cache.empty()) {
1081       if (llvm::Error Err = GlobalModuleIndex::writeIndex(
1082               CI.getFileManager(), CI.getPCHContainerReader(), Cache)) {
1083         // FIXME this drops the error on the floor, but
1084         // Index/pch-from-libclang.c seems to rely on dropping at least some of
1085         // the error conditions!
1086         consumeError(std::move(Err));
1087       }
1088     }
1089   }
1090 
1091   return llvm::Error::success();
1092 }
1093 
1094 void FrontendAction::EndSourceFile() {
1095   CompilerInstance &CI = getCompilerInstance();
1096 
1097   // Inform the diagnostic client we are done with this source file.
1098   CI.getDiagnosticClient().EndSourceFile();
1099 
1100   // Inform the preprocessor we are done.
1101   if (CI.hasPreprocessor())
1102     CI.getPreprocessor().EndSourceFile();
1103 
1104   // Finalize the action.
1105   EndSourceFileAction();
1106 
1107   // Sema references the ast consumer, so reset sema first.
1108   //
1109   // FIXME: There is more per-file stuff we could just drop here?
1110   bool DisableFree = CI.getFrontendOpts().DisableFree;
1111   if (DisableFree) {
1112     CI.resetAndLeakSema();
1113     CI.resetAndLeakASTContext();
1114     llvm::BuryPointer(CI.takeASTConsumer().get());
1115   } else {
1116     CI.setSema(nullptr);
1117     CI.setASTContext(nullptr);
1118     CI.setASTConsumer(nullptr);
1119   }
1120 
1121   if (CI.getFrontendOpts().ShowStats) {
1122     llvm::errs() << "\nSTATISTICS FOR '" << getCurrentFileOrBufferName() << "':\n";
1123     CI.getPreprocessor().PrintStats();
1124     CI.getPreprocessor().getIdentifierTable().PrintStats();
1125     CI.getPreprocessor().getHeaderSearchInfo().PrintStats();
1126     CI.getSourceManager().PrintStats();
1127     llvm::errs() << "\n";
1128   }
1129 
1130   // Cleanup the output streams, and erase the output files if instructed by the
1131   // FrontendAction.
1132   CI.clearOutputFiles(/*EraseFiles=*/shouldEraseOutputFiles());
1133 
1134   // The resources are owned by AST when the current file is AST.
1135   // So we reset the resources here to avoid users accessing it
1136   // accidently.
1137   if (isCurrentFileAST()) {
1138     if (DisableFree) {
1139       CI.resetAndLeakPreprocessor();
1140       CI.resetAndLeakSourceManager();
1141       CI.resetAndLeakFileManager();
1142       llvm::BuryPointer(std::move(CurrentASTUnit));
1143     } else {
1144       CI.setPreprocessor(nullptr);
1145       CI.setSourceManager(nullptr);
1146       CI.setFileManager(nullptr);
1147     }
1148   }
1149 
1150   setCompilerInstance(nullptr);
1151   setCurrentInput(FrontendInputFile());
1152   CI.getLangOpts().setCompilingModule(LangOptions::CMK_None);
1153 }
1154 
1155 bool FrontendAction::shouldEraseOutputFiles() {
1156   return getCompilerInstance().getDiagnostics().hasErrorOccurred();
1157 }
1158 
1159 //===----------------------------------------------------------------------===//
1160 // Utility Actions
1161 //===----------------------------------------------------------------------===//
1162 
1163 void ASTFrontendAction::ExecuteAction() {
1164   CompilerInstance &CI = getCompilerInstance();
1165   if (!CI.hasPreprocessor())
1166     return;
1167   // This is a fallback: If the client forgets to invoke this, we mark the
1168   // current stack as the bottom. Though not optimal, this could help prevent
1169   // stack overflow during deep recursion.
1170   clang::noteBottomOfStack();
1171 
1172   // FIXME: Move the truncation aspect of this into Sema, we delayed this till
1173   // here so the source manager would be initialized.
1174   if (hasCodeCompletionSupport() &&
1175       !CI.getFrontendOpts().CodeCompletionAt.FileName.empty())
1176     CI.createCodeCompletionConsumer();
1177 
1178   // Use a code completion consumer?
1179   CodeCompleteConsumer *CompletionConsumer = nullptr;
1180   if (CI.hasCodeCompletionConsumer())
1181     CompletionConsumer = &CI.getCodeCompletionConsumer();
1182 
1183   if (!CI.hasSema())
1184     CI.createSema(getTranslationUnitKind(), CompletionConsumer);
1185 
1186   ParseAST(CI.getSema(), CI.getFrontendOpts().ShowStats,
1187            CI.getFrontendOpts().SkipFunctionBodies);
1188 }
1189 
1190 void PluginASTAction::anchor() { }
1191 
1192 std::unique_ptr<ASTConsumer>
1193 PreprocessorFrontendAction::CreateASTConsumer(CompilerInstance &CI,
1194                                               StringRef InFile) {
1195   llvm_unreachable("Invalid CreateASTConsumer on preprocessor action!");
1196 }
1197 
1198 bool WrapperFrontendAction::PrepareToExecuteAction(CompilerInstance &CI) {
1199   return WrappedAction->PrepareToExecuteAction(CI);
1200 }
1201 std::unique_ptr<ASTConsumer>
1202 WrapperFrontendAction::CreateASTConsumer(CompilerInstance &CI,
1203                                          StringRef InFile) {
1204   return WrappedAction->CreateASTConsumer(CI, InFile);
1205 }
1206 bool WrapperFrontendAction::BeginInvocation(CompilerInstance &CI) {
1207   return WrappedAction->BeginInvocation(CI);
1208 }
1209 bool WrapperFrontendAction::BeginSourceFileAction(CompilerInstance &CI) {
1210   WrappedAction->setCurrentInput(getCurrentInput());
1211   WrappedAction->setCompilerInstance(&CI);
1212   auto Ret = WrappedAction->BeginSourceFileAction(CI);
1213   // BeginSourceFileAction may change CurrentInput, e.g. during module builds.
1214   setCurrentInput(WrappedAction->getCurrentInput());
1215   return Ret;
1216 }
1217 void WrapperFrontendAction::ExecuteAction() {
1218   WrappedAction->ExecuteAction();
1219 }
1220 void WrapperFrontendAction::EndSourceFile() { WrappedAction->EndSourceFile(); }
1221 void WrapperFrontendAction::EndSourceFileAction() {
1222   WrappedAction->EndSourceFileAction();
1223 }
1224 bool WrapperFrontendAction::shouldEraseOutputFiles() {
1225   return WrappedAction->shouldEraseOutputFiles();
1226 }
1227 
1228 bool WrapperFrontendAction::usesPreprocessorOnly() const {
1229   return WrappedAction->usesPreprocessorOnly();
1230 }
1231 TranslationUnitKind WrapperFrontendAction::getTranslationUnitKind() {
1232   return WrappedAction->getTranslationUnitKind();
1233 }
1234 bool WrapperFrontendAction::hasPCHSupport() const {
1235   return WrappedAction->hasPCHSupport();
1236 }
1237 bool WrapperFrontendAction::hasASTFileSupport() const {
1238   return WrappedAction->hasASTFileSupport();
1239 }
1240 bool WrapperFrontendAction::hasIRSupport() const {
1241   return WrappedAction->hasIRSupport();
1242 }
1243 bool WrapperFrontendAction::hasCodeCompletionSupport() const {
1244   return WrappedAction->hasCodeCompletionSupport();
1245 }
1246 
1247 WrapperFrontendAction::WrapperFrontendAction(
1248     std::unique_ptr<FrontendAction> WrappedAction)
1249   : WrappedAction(std::move(WrappedAction)) {}
1250