1 //===--- ModuleBuilder.cpp - Emit LLVM Code from ASTs ---------------------===// 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 // This builds an AST and converts it to LLVM Code. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "clang/CodeGen/ModuleBuilder.h" 15 #include "CGDebugInfo.h" 16 #include "CodeGenModule.h" 17 #include "clang/AST/ASTContext.h" 18 #include "clang/AST/DeclObjC.h" 19 #include "clang/AST/Expr.h" 20 #include "clang/Basic/Diagnostic.h" 21 #include "clang/Basic/TargetInfo.h" 22 #include "clang/Frontend/CodeGenOptions.h" 23 #include "llvm/ADT/StringRef.h" 24 #include "llvm/IR/DataLayout.h" 25 #include "llvm/IR/LLVMContext.h" 26 #include "llvm/IR/Module.h" 27 #include <memory> 28 29 using namespace clang; 30 using namespace CodeGen; 31 32 namespace { 33 class CodeGeneratorImpl : public CodeGenerator { 34 DiagnosticsEngine &Diags; 35 ASTContext *Ctx; 36 const HeaderSearchOptions &HeaderSearchOpts; // Only used for debug info. 37 const PreprocessorOptions &PreprocessorOpts; // Only used for debug info. 38 const CodeGenOptions CodeGenOpts; // Intentionally copied in. 39 40 unsigned HandlingTopLevelDecls; 41 42 /// Use this when emitting decls to block re-entrant decl emission. It will 43 /// emit all deferred decls on scope exit. Set EmitDeferred to false if decl 44 /// emission must be deferred longer, like at the end of a tag definition. 45 struct HandlingTopLevelDeclRAII { 46 CodeGeneratorImpl &Self; 47 bool EmitDeferred; 48 HandlingTopLevelDeclRAII(CodeGeneratorImpl &Self, 49 bool EmitDeferred = true) 50 : Self(Self), EmitDeferred(EmitDeferred) { 51 ++Self.HandlingTopLevelDecls; 52 } 53 ~HandlingTopLevelDeclRAII() { 54 unsigned Level = --Self.HandlingTopLevelDecls; 55 if (Level == 0 && EmitDeferred) 56 Self.EmitDeferredDecls(); 57 } 58 }; 59 60 CoverageSourceInfo *CoverageInfo; 61 62 protected: 63 std::unique_ptr<llvm::Module> M; 64 std::unique_ptr<CodeGen::CodeGenModule> Builder; 65 66 private: 67 SmallVector<CXXMethodDecl *, 8> DeferredInlineMethodDefinitions; 68 69 public: 70 CodeGeneratorImpl(DiagnosticsEngine &diags, llvm::StringRef ModuleName, 71 const HeaderSearchOptions &HSO, 72 const PreprocessorOptions &PPO, const CodeGenOptions &CGO, 73 llvm::LLVMContext &C, 74 CoverageSourceInfo *CoverageInfo = nullptr) 75 : Diags(diags), Ctx(nullptr), HeaderSearchOpts(HSO), 76 PreprocessorOpts(PPO), CodeGenOpts(CGO), HandlingTopLevelDecls(0), 77 CoverageInfo(CoverageInfo), M(new llvm::Module(ModuleName, C)) { 78 C.setDiscardValueNames(CGO.DiscardValueNames); 79 } 80 81 ~CodeGeneratorImpl() override { 82 // There should normally not be any leftover inline method definitions. 83 assert(DeferredInlineMethodDefinitions.empty() || 84 Diags.hasErrorOccurred()); 85 } 86 87 CodeGenModule &CGM() { 88 return *Builder; 89 } 90 91 llvm::Module *GetModule() { 92 return M.get(); 93 } 94 95 CGDebugInfo *getCGDebugInfo() { 96 return Builder->getModuleDebugInfo(); 97 } 98 99 llvm::Module *ReleaseModule() { 100 return M.release(); 101 } 102 103 const Decl *GetDeclForMangledName(StringRef MangledName) { 104 GlobalDecl Result; 105 if (!Builder->lookupRepresentativeDecl(MangledName, Result)) 106 return nullptr; 107 const Decl *D = Result.getCanonicalDecl().getDecl(); 108 if (auto FD = dyn_cast<FunctionDecl>(D)) { 109 if (FD->hasBody(FD)) 110 return FD; 111 } else if (auto TD = dyn_cast<TagDecl>(D)) { 112 if (auto Def = TD->getDefinition()) 113 return Def; 114 } 115 return D; 116 } 117 118 llvm::Constant *GetAddrOfGlobal(GlobalDecl global, bool isForDefinition) { 119 return Builder->GetAddrOfGlobal(global, ForDefinition_t(isForDefinition)); 120 } 121 122 void Initialize(ASTContext &Context) override { 123 Ctx = &Context; 124 125 M->setTargetTriple(Ctx->getTargetInfo().getTriple().getTriple()); 126 M->setDataLayout(Ctx->getTargetInfo().getDataLayout()); 127 Builder.reset(new CodeGen::CodeGenModule(Context, HeaderSearchOpts, 128 PreprocessorOpts, CodeGenOpts, 129 *M, Diags, CoverageInfo)); 130 131 for (auto &&Lib : CodeGenOpts.DependentLibraries) 132 Builder->AddDependentLib(Lib); 133 for (auto &&Opt : CodeGenOpts.LinkerOptions) 134 Builder->AppendLinkerOptions(Opt); 135 } 136 137 void HandleCXXStaticMemberVarInstantiation(VarDecl *VD) override { 138 if (Diags.hasErrorOccurred()) 139 return; 140 141 Builder->HandleCXXStaticMemberVarInstantiation(VD); 142 } 143 144 bool HandleTopLevelDecl(DeclGroupRef DG) override { 145 if (Diags.hasErrorOccurred()) 146 return true; 147 148 HandlingTopLevelDeclRAII HandlingDecl(*this); 149 150 // Make sure to emit all elements of a Decl. 151 for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I) 152 Builder->EmitTopLevelDecl(*I); 153 154 return true; 155 } 156 157 void EmitDeferredDecls() { 158 if (DeferredInlineMethodDefinitions.empty()) 159 return; 160 161 // Emit any deferred inline method definitions. Note that more deferred 162 // methods may be added during this loop, since ASTConsumer callbacks 163 // can be invoked if AST inspection results in declarations being added. 164 HandlingTopLevelDeclRAII HandlingDecl(*this); 165 for (unsigned I = 0; I != DeferredInlineMethodDefinitions.size(); ++I) 166 Builder->EmitTopLevelDecl(DeferredInlineMethodDefinitions[I]); 167 DeferredInlineMethodDefinitions.clear(); 168 } 169 170 void HandleInlineFunctionDefinition(FunctionDecl *D) override { 171 if (Diags.hasErrorOccurred()) 172 return; 173 174 assert(D->doesThisDeclarationHaveABody()); 175 176 // Handle friend functions. 177 if (D->isInIdentifierNamespace(Decl::IDNS_OrdinaryFriend)) { 178 if (Ctx->getTargetInfo().getCXXABI().isMicrosoft() 179 && !D->getLexicalDeclContext()->isDependentContext()) 180 Builder->EmitTopLevelDecl(D); 181 return; 182 } 183 184 // Otherwise, must be a method. 185 auto MD = cast<CXXMethodDecl>(D); 186 187 // We may want to emit this definition. However, that decision might be 188 // based on computing the linkage, and we have to defer that in case we 189 // are inside of something that will change the method's final linkage, 190 // e.g. 191 // typedef struct { 192 // void bar(); 193 // void foo() { bar(); } 194 // } A; 195 DeferredInlineMethodDefinitions.push_back(MD); 196 197 // Provide some coverage mapping even for methods that aren't emitted. 198 // Don't do this for templated classes though, as they may not be 199 // instantiable. 200 if (!MD->getParent()->getDescribedClassTemplate()) 201 Builder->AddDeferredUnusedCoverageMapping(MD); 202 } 203 204 /// HandleTagDeclDefinition - This callback is invoked each time a TagDecl 205 /// to (e.g. struct, union, enum, class) is completed. This allows the 206 /// client hack on the type, which can occur at any point in the file 207 /// (because these can be defined in declspecs). 208 void HandleTagDeclDefinition(TagDecl *D) override { 209 if (Diags.hasErrorOccurred()) 210 return; 211 212 // Don't allow re-entrant calls to CodeGen triggered by PCH 213 // deserialization to emit deferred decls. 214 HandlingTopLevelDeclRAII HandlingDecl(*this, /*EmitDeferred=*/false); 215 216 Builder->UpdateCompletedType(D); 217 218 // For MSVC compatibility, treat declarations of static data members with 219 // inline initializers as definitions. 220 if (Ctx->getTargetInfo().getCXXABI().isMicrosoft()) { 221 for (Decl *Member : D->decls()) { 222 if (VarDecl *VD = dyn_cast<VarDecl>(Member)) { 223 if (Ctx->isMSStaticDataMemberInlineDefinition(VD) && 224 Ctx->DeclMustBeEmitted(VD)) { 225 Builder->EmitGlobal(VD); 226 } 227 } 228 } 229 } 230 // For OpenMP emit declare reduction functions, if required. 231 if (Ctx->getLangOpts().OpenMP) { 232 for (Decl *Member : D->decls()) { 233 if (auto *DRD = dyn_cast<OMPDeclareReductionDecl>(Member)) { 234 if (Ctx->DeclMustBeEmitted(DRD)) 235 Builder->EmitGlobal(DRD); 236 } 237 } 238 } 239 } 240 241 void HandleTagDeclRequiredDefinition(const TagDecl *D) override { 242 if (Diags.hasErrorOccurred()) 243 return; 244 245 // Don't allow re-entrant calls to CodeGen triggered by PCH 246 // deserialization to emit deferred decls. 247 HandlingTopLevelDeclRAII HandlingDecl(*this, /*EmitDeferred=*/false); 248 249 if (CodeGen::CGDebugInfo *DI = Builder->getModuleDebugInfo()) 250 if (const RecordDecl *RD = dyn_cast<RecordDecl>(D)) 251 DI->completeRequiredType(RD); 252 } 253 254 void HandleTranslationUnit(ASTContext &Ctx) override { 255 // Release the Builder when there is no error. 256 if (!Diags.hasErrorOccurred() && Builder) 257 Builder->Release(); 258 259 // If there are errors before or when releasing the Builder, reset 260 // the module to stop here before invoking the backend. 261 if (Diags.hasErrorOccurred()) { 262 if (Builder) 263 Builder->clear(); 264 M.reset(); 265 return; 266 } 267 } 268 269 void AssignInheritanceModel(CXXRecordDecl *RD) override { 270 if (Diags.hasErrorOccurred()) 271 return; 272 273 Builder->RefreshTypeCacheForClass(RD); 274 } 275 276 void CompleteTentativeDefinition(VarDecl *D) override { 277 if (Diags.hasErrorOccurred()) 278 return; 279 280 Builder->EmitTentativeDefinition(D); 281 } 282 283 void HandleVTable(CXXRecordDecl *RD) override { 284 if (Diags.hasErrorOccurred()) 285 return; 286 287 Builder->EmitVTable(RD); 288 } 289 }; 290 } 291 292 void CodeGenerator::anchor() { } 293 294 CodeGenModule &CodeGenerator::CGM() { 295 return static_cast<CodeGeneratorImpl*>(this)->CGM(); 296 } 297 298 llvm::Module *CodeGenerator::GetModule() { 299 return static_cast<CodeGeneratorImpl*>(this)->GetModule(); 300 } 301 302 llvm::Module *CodeGenerator::ReleaseModule() { 303 return static_cast<CodeGeneratorImpl*>(this)->ReleaseModule(); 304 } 305 306 CGDebugInfo *CodeGenerator::getCGDebugInfo() { 307 return static_cast<CodeGeneratorImpl*>(this)->getCGDebugInfo(); 308 } 309 310 const Decl *CodeGenerator::GetDeclForMangledName(llvm::StringRef name) { 311 return static_cast<CodeGeneratorImpl*>(this)->GetDeclForMangledName(name); 312 } 313 314 llvm::Constant *CodeGenerator::GetAddrOfGlobal(GlobalDecl global, 315 bool isForDefinition) { 316 return static_cast<CodeGeneratorImpl*>(this) 317 ->GetAddrOfGlobal(global, isForDefinition); 318 } 319 320 CodeGenerator *clang::CreateLLVMCodeGen( 321 DiagnosticsEngine &Diags, llvm::StringRef ModuleName, 322 const HeaderSearchOptions &HeaderSearchOpts, 323 const PreprocessorOptions &PreprocessorOpts, const CodeGenOptions &CGO, 324 llvm::LLVMContext &C, CoverageSourceInfo *CoverageInfo) { 325 return new CodeGeneratorImpl(Diags, ModuleName, HeaderSearchOpts, 326 PreprocessorOpts, CGO, C, CoverageInfo); 327 } 328