1 //===--- ObjectFilePCHContainerOperations.cpp -----------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "clang/CodeGen/ObjectFilePCHContainerOperations.h"
11 #include "CGDebugInfo.h"
12 #include "CodeGenModule.h"
13 #include "clang/AST/ASTContext.h"
14 #include "clang/AST/DeclObjC.h"
15 #include "clang/AST/Expr.h"
16 #include "clang/AST/RecursiveASTVisitor.h"
17 #include "clang/Basic/CodeGenOptions.h"
18 #include "clang/Basic/Diagnostic.h"
19 #include "clang/Basic/TargetInfo.h"
20 #include "clang/CodeGen/BackendUtil.h"
21 #include "clang/Frontend/CompilerInstance.h"
22 #include "clang/Lex/HeaderSearch.h"
23 #include "clang/Lex/Preprocessor.h"
24 #include "llvm/ADT/StringRef.h"
25 #include "llvm/Bitcode/BitstreamReader.h"
26 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
27 #include "llvm/IR/Constants.h"
28 #include "llvm/IR/DataLayout.h"
29 #include "llvm/IR/LLVMContext.h"
30 #include "llvm/IR/Module.h"
31 #include "llvm/Object/COFF.h"
32 #include "llvm/Object/ObjectFile.h"
33 #include "llvm/Support/Path.h"
34 #include "llvm/Support/TargetRegistry.h"
38 using namespace clang;
40 #define DEBUG_TYPE "pchcontainer"
43 class PCHContainerGenerator : public ASTConsumer {
44 DiagnosticsEngine &Diags;
45 const std::string MainFileName;
46 const std::string OutputFileName;
49 const HeaderSearchOptions &HeaderSearchOpts;
50 const PreprocessorOptions &PreprocessorOpts;
51 CodeGenOptions CodeGenOpts;
52 const TargetOptions TargetOpts;
53 const LangOptions LangOpts;
54 std::unique_ptr<llvm::LLVMContext> VMContext;
55 std::unique_ptr<llvm::Module> M;
56 std::unique_ptr<CodeGen::CodeGenModule> Builder;
57 std::unique_ptr<raw_pwrite_stream> OS;
58 std::shared_ptr<PCHBuffer> Buffer;
60 /// Visit every type and emit debug info for it.
61 struct DebugTypeVisitor : public RecursiveASTVisitor<DebugTypeVisitor> {
62 clang::CodeGen::CGDebugInfo &DI;
64 DebugTypeVisitor(clang::CodeGen::CGDebugInfo &DI, ASTContext &Ctx)
67 /// Determine whether this type can be represented in DWARF.
68 static bool CanRepresent(const Type *Ty) {
69 return !Ty->isDependentType() && !Ty->isUndeducedType();
72 bool VisitImportDecl(ImportDecl *D) {
73 if (!D->getImportedOwningModule())
74 DI.EmitImportDecl(*D);
78 bool VisitTypeDecl(TypeDecl *D) {
79 // TagDecls may be deferred until after all decls have been merged and we
80 // know the complete type. Pure forward declarations will be skipped, but
81 // they don't need to be emitted into the module anyway.
82 if (auto *TD = dyn_cast<TagDecl>(D))
83 if (!TD->isCompleteDefinition())
86 QualType QualTy = Ctx.getTypeDeclType(D);
87 if (!QualTy.isNull() && CanRepresent(QualTy.getTypePtr()))
88 DI.getOrCreateStandaloneType(QualTy, D->getLocation());
92 bool VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
93 QualType QualTy(D->getTypeForDecl(), 0);
94 if (!QualTy.isNull() && CanRepresent(QualTy.getTypePtr()))
95 DI.getOrCreateStandaloneType(QualTy, D->getLocation());
99 bool VisitFunctionDecl(FunctionDecl *D) {
100 if (isa<CXXMethodDecl>(D))
101 // This is not yet supported. Constructing the `this' argument
102 // mandates a CodeGenFunction.
105 SmallVector<QualType, 16> ArgTypes;
106 for (auto i : D->parameters())
107 ArgTypes.push_back(i->getType());
108 QualType RetTy = D->getReturnType();
109 QualType FnTy = Ctx.getFunctionType(RetTy, ArgTypes,
110 FunctionProtoType::ExtProtoInfo());
111 if (CanRepresent(FnTy.getTypePtr()))
112 DI.EmitFunctionDecl(D, D->getLocation(), FnTy);
116 bool VisitObjCMethodDecl(ObjCMethodDecl *D) {
117 if (!D->getClassInterface())
120 bool selfIsPseudoStrong, selfIsConsumed;
121 SmallVector<QualType, 16> ArgTypes;
122 ArgTypes.push_back(D->getSelfType(Ctx, D->getClassInterface(),
123 selfIsPseudoStrong, selfIsConsumed));
124 ArgTypes.push_back(Ctx.getObjCSelType());
125 for (auto i : D->parameters())
126 ArgTypes.push_back(i->getType());
127 QualType RetTy = D->getReturnType();
128 QualType FnTy = Ctx.getFunctionType(RetTy, ArgTypes,
129 FunctionProtoType::ExtProtoInfo());
130 if (CanRepresent(FnTy.getTypePtr()))
131 DI.EmitFunctionDecl(D, D->getLocation(), FnTy);
137 PCHContainerGenerator(CompilerInstance &CI, const std::string &MainFileName,
138 const std::string &OutputFileName,
139 std::unique_ptr<raw_pwrite_stream> OS,
140 std::shared_ptr<PCHBuffer> Buffer)
141 : Diags(CI.getDiagnostics()), MainFileName(MainFileName),
142 OutputFileName(OutputFileName), Ctx(nullptr),
143 MMap(CI.getPreprocessor().getHeaderSearchInfo().getModuleMap()),
144 HeaderSearchOpts(CI.getHeaderSearchOpts()),
145 PreprocessorOpts(CI.getPreprocessorOpts()),
146 TargetOpts(CI.getTargetOpts()), LangOpts(CI.getLangOpts()),
147 OS(std::move(OS)), Buffer(std::move(Buffer)) {
148 // The debug info output isn't affected by CodeModel and
149 // ThreadModel, but the backend expects them to be nonempty.
150 CodeGenOpts.CodeModel = "default";
151 CodeGenOpts.ThreadModel = "single";
152 CodeGenOpts.DebugTypeExtRefs = true;
153 // When building a module MainFileName is the name of the modulemap file.
154 CodeGenOpts.MainFileName =
155 LangOpts.CurrentModule.empty() ? MainFileName : LangOpts.CurrentModule;
156 CodeGenOpts.setDebugInfo(codegenoptions::FullDebugInfo);
157 CodeGenOpts.setDebuggerTuning(CI.getCodeGenOpts().getDebuggerTuning());
158 CodeGenOpts.DebugPrefixMap =
159 CI.getInvocation().getCodeGenOpts().DebugPrefixMap;
162 ~PCHContainerGenerator() override = default;
164 void Initialize(ASTContext &Context) override {
165 assert(!Ctx && "initialized multiple times");
168 VMContext.reset(new llvm::LLVMContext());
169 M.reset(new llvm::Module(MainFileName, *VMContext));
170 M->setDataLayout(Ctx->getTargetInfo().getDataLayout());
171 Builder.reset(new CodeGen::CodeGenModule(
172 *Ctx, HeaderSearchOpts, PreprocessorOpts, CodeGenOpts, *M, Diags));
174 // Prepare CGDebugInfo to emit debug info for a clang module.
175 auto *DI = Builder->getModuleDebugInfo();
176 StringRef ModuleName = llvm::sys::path::filename(MainFileName);
177 DI->setPCHDescriptor({ModuleName, "", OutputFileName,
178 ASTFileSignature{{{~0U, ~0U, ~0U, ~0U, ~1U}}}});
179 DI->setModuleMap(MMap);
182 bool HandleTopLevelDecl(DeclGroupRef D) override {
183 if (Diags.hasErrorOccurred())
186 // Collect debug info for all decls in this group.
188 if (!I->isFromASTFile()) {
189 DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx);
195 void HandleTopLevelDeclInObjCContainer(DeclGroupRef D) override {
196 HandleTopLevelDecl(D);
199 void HandleTagDeclDefinition(TagDecl *D) override {
200 if (Diags.hasErrorOccurred())
203 if (D->isFromASTFile())
206 // Anonymous tag decls are deferred until we are building their declcontext.
207 if (D->getName().empty())
210 // Defer tag decls until their declcontext is complete.
211 auto *DeclCtx = D->getDeclContext();
213 if (auto *D = dyn_cast<TagDecl>(DeclCtx))
214 if (!D->isCompleteDefinition())
216 DeclCtx = DeclCtx->getParent();
219 DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx);
221 Builder->UpdateCompletedType(D);
224 void HandleTagDeclRequiredDefinition(const TagDecl *D) override {
225 if (Diags.hasErrorOccurred())
228 if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
229 Builder->getModuleDebugInfo()->completeRequiredType(RD);
232 void HandleImplicitImportDecl(ImportDecl *D) override {
233 if (!D->getImportedOwningModule())
234 Builder->getModuleDebugInfo()->EmitImportDecl(*D);
237 /// Emit a container holding the serialized AST.
238 void HandleTranslationUnit(ASTContext &Ctx) override {
239 assert(M && VMContext && Builder);
240 // Delete these on function exit.
241 std::unique_ptr<llvm::LLVMContext> VMContext = std::move(this->VMContext);
242 std::unique_ptr<llvm::Module> M = std::move(this->M);
243 std::unique_ptr<CodeGen::CodeGenModule> Builder = std::move(this->Builder);
245 if (Diags.hasErrorOccurred())
248 M->setTargetTriple(Ctx.getTargetInfo().getTriple().getTriple());
249 M->setDataLayout(Ctx.getTargetInfo().getDataLayout());
251 // PCH files don't have a signature field in the control block,
252 // but LLVM detects DWO CUs by looking for a non-zero DWO id.
253 // We use the lower 64 bits for debug info.
256 ? (uint64_t)Buffer->Signature[1] << 32 | Buffer->Signature[0]
258 Builder->getModuleDebugInfo()->setDwoId(Signature);
260 // Finalize the Builder.
264 // Ensure the target exists.
266 auto Triple = Ctx.getTargetInfo().getTriple();
267 if (!llvm::TargetRegistry::lookupTarget(Triple.getTriple(), Error))
268 llvm::report_fatal_error(Error);
270 // Emit the serialized Clang AST into its own section.
271 assert(Buffer->IsComplete && "serialization did not complete");
272 auto &SerializedAST = Buffer->Data;
273 auto Size = SerializedAST.size();
274 auto Int8Ty = llvm::Type::getInt8Ty(*VMContext);
275 auto *Ty = llvm::ArrayType::get(Int8Ty, Size);
276 auto *Data = llvm::ConstantDataArray::getString(
277 *VMContext, StringRef(SerializedAST.data(), Size),
279 auto *ASTSym = new llvm::GlobalVariable(
280 *M, Ty, /*constant*/ true, llvm::GlobalVariable::InternalLinkage, Data,
282 // The on-disk hashtable needs to be aligned.
283 ASTSym->setAlignment(8);
285 // Mach-O also needs a segment name.
286 if (Triple.isOSBinFormatMachO())
287 ASTSym->setSection("__CLANG,__clangast");
288 // COFF has an eight character length limit.
289 else if (Triple.isOSBinFormatCOFF())
290 ASTSym->setSection("clangast");
292 ASTSym->setSection("__clangast");
295 // Print the IR for the PCH container to the debug output.
296 llvm::SmallString<0> Buffer;
297 clang::EmitBackendOutput(
298 Diags, HeaderSearchOpts, CodeGenOpts, TargetOpts, LangOpts,
299 Ctx.getTargetInfo().getDataLayout(), M.get(),
300 BackendAction::Backend_EmitLL,
301 llvm::make_unique<llvm::raw_svector_ostream>(Buffer));
302 llvm::dbgs() << Buffer;
305 // Use the LLVM backend to emit the pch container.
306 clang::EmitBackendOutput(Diags, HeaderSearchOpts, CodeGenOpts, TargetOpts,
307 LangOpts, Ctx.getTargetInfo().getDataLayout(),
308 M.get(), BackendAction::Backend_EmitObj,
311 // Free the memory for the temporary buffer.
312 llvm::SmallVector<char, 0> Empty;
313 SerializedAST = std::move(Empty);
317 } // anonymous namespace
319 std::unique_ptr<ASTConsumer>
320 ObjectFilePCHContainerWriter::CreatePCHContainerGenerator(
321 CompilerInstance &CI, const std::string &MainFileName,
322 const std::string &OutputFileName,
323 std::unique_ptr<llvm::raw_pwrite_stream> OS,
324 std::shared_ptr<PCHBuffer> Buffer) const {
325 return llvm::make_unique<PCHContainerGenerator>(
326 CI, MainFileName, OutputFileName, std::move(OS), Buffer);
330 ObjectFilePCHContainerReader::ExtractPCH(llvm::MemoryBufferRef Buffer) const {
332 auto OFOrErr = llvm::object::ObjectFile::createObjectFile(Buffer);
334 auto &OF = OFOrErr.get();
335 bool IsCOFF = isa<llvm::object::COFFObjectFile>(*OF);
336 // Find the clang AST section in the container.
337 for (auto &Section : OF->sections()) {
339 Section.getName(Name);
340 if ((!IsCOFF && Name == "__clangast") || (IsCOFF && Name == "clangast")) {
341 Section.getContents(PCH);
346 handleAllErrors(OFOrErr.takeError(), [&](const llvm::ErrorInfoBase &EIB) {
347 if (EIB.convertToErrorCode() ==
348 llvm::object::object_error::invalid_file_type)
349 // As a fallback, treat the buffer as a raw AST.
350 PCH = Buffer.getBuffer();
352 EIB.log(llvm::errs());