1 //===--- ObjectFilePCHContainerOperations.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/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/Diagnostic.h"
18 #include "clang/Basic/TargetInfo.h"
19 #include "clang/CodeGen/BackendUtil.h"
20 #include "clang/Frontend/CodeGenOptions.h"
21 #include "clang/Frontend/CompilerInstance.h"
22 #include "clang/Lex/HeaderSearch.h"
23 #include "clang/Lex/Preprocessor.h"
24 #include "clang/Serialization/ASTWriter.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/Bitcode/BitstreamReader.h"
27 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
28 #include "llvm/IR/Constants.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/IR/LLVMContext.h"
31 #include "llvm/IR/Module.h"
32 #include "llvm/Object/COFF.h"
33 #include "llvm/Object/ObjectFile.h"
34 #include "llvm/Support/Path.h"
35 #include "llvm/Support/TargetRegistry.h"
36 #include <memory>
37 #include <utility>
38
39 using namespace clang;
40
41 #define DEBUG_TYPE "pchcontainer"
42
43 namespace {
44 class PCHContainerGenerator : public ASTConsumer {
45 DiagnosticsEngine &Diags;
46 const std::string MainFileName;
47 const std::string OutputFileName;
48 ASTContext *Ctx;
49 ModuleMap &MMap;
50 const HeaderSearchOptions &HeaderSearchOpts;
51 const PreprocessorOptions &PreprocessorOpts;
52 CodeGenOptions CodeGenOpts;
53 const TargetOptions TargetOpts;
54 const LangOptions LangOpts;
55 std::unique_ptr<llvm::LLVMContext> VMContext;
56 std::unique_ptr<llvm::Module> M;
57 std::unique_ptr<CodeGen::CodeGenModule> Builder;
58 raw_pwrite_stream *OS;
59 std::shared_ptr<PCHBuffer> Buffer;
60
61 /// Visit every type and emit debug info for it.
62 struct DebugTypeVisitor : public RecursiveASTVisitor<DebugTypeVisitor> {
63 clang::CodeGen::CGDebugInfo &DI;
64 ASTContext &Ctx;
DebugTypeVisitor__anon42fdf0c40111::PCHContainerGenerator::DebugTypeVisitor65 DebugTypeVisitor(clang::CodeGen::CGDebugInfo &DI, ASTContext &Ctx)
66 : DI(DI), Ctx(Ctx) {}
67
68 /// Determine whether this type can be represented in DWARF.
CanRepresent__anon42fdf0c40111::PCHContainerGenerator::DebugTypeVisitor69 static bool CanRepresent(const Type *Ty) {
70 return !Ty->isDependentType() && !Ty->isUndeducedType();
71 }
72
VisitImportDecl__anon42fdf0c40111::PCHContainerGenerator::DebugTypeVisitor73 bool VisitImportDecl(ImportDecl *D) {
74 auto *Import = cast<ImportDecl>(D);
75 if (!Import->getImportedOwningModule())
76 DI.EmitImportDecl(*Import);
77 return true;
78 }
79
VisitTypeDecl__anon42fdf0c40111::PCHContainerGenerator::DebugTypeVisitor80 bool VisitTypeDecl(TypeDecl *D) {
81 // TagDecls may be deferred until after all decls have been merged and we
82 // know the complete type. Pure forward declarations will be skipped, but
83 // they don't need to be emitted into the module anyway.
84 if (auto *TD = dyn_cast<TagDecl>(D))
85 if (!TD->isCompleteDefinition())
86 return true;
87
88 QualType QualTy = Ctx.getTypeDeclType(D);
89 if (!QualTy.isNull() && CanRepresent(QualTy.getTypePtr()))
90 DI.getOrCreateStandaloneType(QualTy, D->getLocation());
91 return true;
92 }
93
VisitObjCInterfaceDecl__anon42fdf0c40111::PCHContainerGenerator::DebugTypeVisitor94 bool VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
95 QualType QualTy(D->getTypeForDecl(), 0);
96 if (!QualTy.isNull() && CanRepresent(QualTy.getTypePtr()))
97 DI.getOrCreateStandaloneType(QualTy, D->getLocation());
98 return true;
99 }
100
VisitFunctionDecl__anon42fdf0c40111::PCHContainerGenerator::DebugTypeVisitor101 bool VisitFunctionDecl(FunctionDecl *D) {
102 if (isa<CXXMethodDecl>(D))
103 // This is not yet supported. Constructing the `this' argument
104 // mandates a CodeGenFunction.
105 return true;
106
107 SmallVector<QualType, 16> ArgTypes;
108 for (auto i : D->parameters())
109 ArgTypes.push_back(i->getType());
110 QualType RetTy = D->getReturnType();
111 QualType FnTy = Ctx.getFunctionType(RetTy, ArgTypes,
112 FunctionProtoType::ExtProtoInfo());
113 if (CanRepresent(FnTy.getTypePtr()))
114 DI.EmitFunctionDecl(D, D->getLocation(), FnTy);
115 return true;
116 }
117
VisitObjCMethodDecl__anon42fdf0c40111::PCHContainerGenerator::DebugTypeVisitor118 bool VisitObjCMethodDecl(ObjCMethodDecl *D) {
119 if (!D->getClassInterface())
120 return true;
121
122 bool selfIsPseudoStrong, selfIsConsumed;
123 SmallVector<QualType, 16> ArgTypes;
124 ArgTypes.push_back(D->getSelfType(Ctx, D->getClassInterface(),
125 selfIsPseudoStrong, selfIsConsumed));
126 ArgTypes.push_back(Ctx.getObjCSelType());
127 for (auto i : D->parameters())
128 ArgTypes.push_back(i->getType());
129 QualType RetTy = D->getReturnType();
130 QualType FnTy = Ctx.getFunctionType(RetTy, ArgTypes,
131 FunctionProtoType::ExtProtoInfo());
132 if (CanRepresent(FnTy.getTypePtr()))
133 DI.EmitFunctionDecl(D, D->getLocation(), FnTy);
134 return true;
135 }
136 };
137
138 public:
PCHContainerGenerator(CompilerInstance & CI,const std::string & MainFileName,const std::string & OutputFileName,raw_pwrite_stream * OS,std::shared_ptr<PCHBuffer> Buffer)139 PCHContainerGenerator(CompilerInstance &CI, const std::string &MainFileName,
140 const std::string &OutputFileName,
141 raw_pwrite_stream *OS,
142 std::shared_ptr<PCHBuffer> Buffer)
143 : Diags(CI.getDiagnostics()), MainFileName(MainFileName),
144 OutputFileName(OutputFileName), Ctx(nullptr),
145 MMap(CI.getPreprocessor().getHeaderSearchInfo().getModuleMap()),
146 HeaderSearchOpts(CI.getHeaderSearchOpts()),
147 PreprocessorOpts(CI.getPreprocessorOpts()),
148 TargetOpts(CI.getTargetOpts()), LangOpts(CI.getLangOpts()), OS(OS),
149 Buffer(std::move(Buffer)) {
150 // The debug info output isn't affected by CodeModel and
151 // ThreadModel, but the backend expects them to be nonempty.
152 CodeGenOpts.CodeModel = "default";
153 CodeGenOpts.ThreadModel = "single";
154 CodeGenOpts.DebugTypeExtRefs = true;
155 CodeGenOpts.setDebugInfo(codegenoptions::FullDebugInfo);
156 CodeGenOpts.setDebuggerTuning(CI.getCodeGenOpts().getDebuggerTuning());
157 }
158
159 ~PCHContainerGenerator() override = default;
160
Initialize(ASTContext & Context)161 void Initialize(ASTContext &Context) override {
162 assert(!Ctx && "initialized multiple times");
163
164 Ctx = &Context;
165 VMContext.reset(new llvm::LLVMContext());
166 M.reset(new llvm::Module(MainFileName, *VMContext));
167 M->setDataLayout(Ctx->getTargetInfo().getDataLayout());
168 Builder.reset(new CodeGen::CodeGenModule(
169 *Ctx, HeaderSearchOpts, PreprocessorOpts, CodeGenOpts, *M, Diags));
170
171 // Prepare CGDebugInfo to emit debug info for a clang module.
172 auto *DI = Builder->getModuleDebugInfo();
173 StringRef ModuleName = llvm::sys::path::filename(MainFileName);
174 DI->setPCHDescriptor({ModuleName, "", OutputFileName, ~1ULL});
175 DI->setModuleMap(MMap);
176 }
177
HandleTopLevelDecl(DeclGroupRef D)178 bool HandleTopLevelDecl(DeclGroupRef D) override {
179 if (Diags.hasErrorOccurred())
180 return true;
181
182 // Collect debug info for all decls in this group.
183 for (auto *I : D)
184 if (!I->isFromASTFile()) {
185 DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx);
186 DTV.TraverseDecl(I);
187 }
188 return true;
189 }
190
HandleTopLevelDeclInObjCContainer(DeclGroupRef D)191 void HandleTopLevelDeclInObjCContainer(DeclGroupRef D) override {
192 HandleTopLevelDecl(D);
193 }
194
HandleTagDeclDefinition(TagDecl * D)195 void HandleTagDeclDefinition(TagDecl *D) override {
196 if (Diags.hasErrorOccurred())
197 return;
198
199 if (D->isFromASTFile())
200 return;
201
202 // Anonymous tag decls are deferred until we are building their declcontext.
203 if (D->getName().empty())
204 return;
205
206 // Defer tag decls until their declcontext is complete.
207 auto *DeclCtx = D->getDeclContext();
208 while (DeclCtx) {
209 if (auto *D = dyn_cast<TagDecl>(DeclCtx))
210 if (!D->isCompleteDefinition())
211 return;
212 DeclCtx = DeclCtx->getParent();
213 }
214
215 DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx);
216 DTV.TraverseDecl(D);
217 Builder->UpdateCompletedType(D);
218 }
219
HandleTagDeclRequiredDefinition(const TagDecl * D)220 void HandleTagDeclRequiredDefinition(const TagDecl *D) override {
221 if (Diags.hasErrorOccurred())
222 return;
223
224 if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
225 Builder->getModuleDebugInfo()->completeRequiredType(RD);
226 }
227
228 /// Emit a container holding the serialized AST.
HandleTranslationUnit(ASTContext & Ctx)229 void HandleTranslationUnit(ASTContext &Ctx) override {
230 assert(M && VMContext && Builder);
231 // Delete these on function exit.
232 std::unique_ptr<llvm::LLVMContext> VMContext = std::move(this->VMContext);
233 std::unique_ptr<llvm::Module> M = std::move(this->M);
234 std::unique_ptr<CodeGen::CodeGenModule> Builder = std::move(this->Builder);
235
236 if (Diags.hasErrorOccurred())
237 return;
238
239 M->setTargetTriple(Ctx.getTargetInfo().getTriple().getTriple());
240 M->setDataLayout(Ctx.getTargetInfo().getDataLayout());
241
242 // PCH files don't have a signature field in the control block,
243 // but LLVM detects DWO CUs by looking for a non-zero DWO id.
244 uint64_t Signature = Buffer->Signature ? Buffer->Signature : ~1ULL;
245 Builder->getModuleDebugInfo()->setDwoId(Signature);
246
247 // Finalize the Builder.
248 if (Builder)
249 Builder->Release();
250
251 // Ensure the target exists.
252 std::string Error;
253 auto Triple = Ctx.getTargetInfo().getTriple();
254 if (!llvm::TargetRegistry::lookupTarget(Triple.getTriple(), Error))
255 llvm::report_fatal_error(Error);
256
257 // Emit the serialized Clang AST into its own section.
258 assert(Buffer->IsComplete && "serialization did not complete");
259 auto &SerializedAST = Buffer->Data;
260 auto Size = SerializedAST.size();
261 auto Int8Ty = llvm::Type::getInt8Ty(*VMContext);
262 auto *Ty = llvm::ArrayType::get(Int8Ty, Size);
263 auto *Data = llvm::ConstantDataArray::getString(
264 *VMContext, StringRef(SerializedAST.data(), Size),
265 /*AddNull=*/false);
266 auto *ASTSym = new llvm::GlobalVariable(
267 *M, Ty, /*constant*/ true, llvm::GlobalVariable::InternalLinkage, Data,
268 "__clang_ast");
269 // The on-disk hashtable needs to be aligned.
270 ASTSym->setAlignment(8);
271
272 // Mach-O also needs a segment name.
273 if (Triple.isOSBinFormatMachO())
274 ASTSym->setSection("__CLANG,__clangast");
275 // COFF has an eight character length limit.
276 else if (Triple.isOSBinFormatCOFF())
277 ASTSym->setSection("clangast");
278 else
279 ASTSym->setSection("__clangast");
280
281 DEBUG({
282 // Print the IR for the PCH container to the debug output.
283 llvm::SmallString<0> Buffer;
284 llvm::raw_svector_ostream OS(Buffer);
285 clang::EmitBackendOutput(Diags, CodeGenOpts, TargetOpts, LangOpts,
286 Ctx.getTargetInfo().getDataLayout(), M.get(),
287 BackendAction::Backend_EmitLL, &OS);
288 llvm::dbgs() << Buffer;
289 });
290
291 // Use the LLVM backend to emit the pch container.
292 clang::EmitBackendOutput(Diags, CodeGenOpts, TargetOpts, LangOpts,
293 Ctx.getTargetInfo().getDataLayout(), M.get(),
294 BackendAction::Backend_EmitObj, OS);
295
296 // Make sure the pch container hits disk.
297 OS->flush();
298
299 // Free the memory for the temporary buffer.
300 llvm::SmallVector<char, 0> Empty;
301 SerializedAST = std::move(Empty);
302 }
303 };
304
305 } // anonymous namespace
306
307 std::unique_ptr<ASTConsumer>
CreatePCHContainerGenerator(CompilerInstance & CI,const std::string & MainFileName,const std::string & OutputFileName,llvm::raw_pwrite_stream * OS,std::shared_ptr<PCHBuffer> Buffer) const308 ObjectFilePCHContainerWriter::CreatePCHContainerGenerator(
309 CompilerInstance &CI, const std::string &MainFileName,
310 const std::string &OutputFileName, llvm::raw_pwrite_stream *OS,
311 std::shared_ptr<PCHBuffer> Buffer) const {
312 return llvm::make_unique<PCHContainerGenerator>(CI, MainFileName,
313 OutputFileName, OS, Buffer);
314 }
315
ExtractPCH(llvm::MemoryBufferRef Buffer,llvm::BitstreamReader & StreamFile) const316 void ObjectFilePCHContainerReader::ExtractPCH(
317 llvm::MemoryBufferRef Buffer, llvm::BitstreamReader &StreamFile) const {
318 if (auto OF = llvm::object::ObjectFile::createObjectFile(Buffer)) {
319 auto *Obj = OF.get().get();
320 bool IsCOFF = isa<llvm::object::COFFObjectFile>(Obj);
321 // Find the clang AST section in the container.
322 for (auto &Section : OF->get()->sections()) {
323 StringRef Name;
324 Section.getName(Name);
325 if ((!IsCOFF && Name == "__clangast") ||
326 ( IsCOFF && Name == "clangast")) {
327 StringRef Buf;
328 Section.getContents(Buf);
329 StreamFile.init((const unsigned char *)Buf.begin(),
330 (const unsigned char *)Buf.end());
331 return;
332 }
333 }
334 }
335
336 // As a fallback, treat the buffer as a raw AST.
337 StreamFile.init((const unsigned char *)Buffer.getBufferStart(),
338 (const unsigned char *)Buffer.getBufferEnd());
339 }
340