1 //===--- CodeGenModule.cpp - Emit LLVM Code from ASTs for a Module --------===// 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 coordinates the per-module state used while generating code. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "CodeGenModule.h" 15 #include "CGCUDARuntime.h" 16 #include "CGCXXABI.h" 17 #include "CGCall.h" 18 #include "CGDebugInfo.h" 19 #include "CGObjCRuntime.h" 20 #include "CGOpenCLRuntime.h" 21 #include "CodeGenFunction.h" 22 #include "CodeGenTBAA.h" 23 #include "TargetInfo.h" 24 #include "clang/AST/ASTContext.h" 25 #include "clang/AST/CharUnits.h" 26 #include "clang/AST/DeclCXX.h" 27 #include "clang/AST/DeclObjC.h" 28 #include "clang/AST/DeclTemplate.h" 29 #include "clang/AST/Mangle.h" 30 #include "clang/AST/RecordLayout.h" 31 #include "clang/AST/RecursiveASTVisitor.h" 32 #include "clang/Basic/Builtins.h" 33 #include "clang/Basic/CharInfo.h" 34 #include "clang/Basic/Diagnostic.h" 35 #include "clang/Basic/Module.h" 36 #include "clang/Basic/SourceManager.h" 37 #include "clang/Basic/TargetInfo.h" 38 #include "clang/Frontend/CodeGenOptions.h" 39 #include "llvm/ADT/APSInt.h" 40 #include "llvm/ADT/Triple.h" 41 #include "llvm/IR/CallingConv.h" 42 #include "llvm/IR/DataLayout.h" 43 #include "llvm/IR/Intrinsics.h" 44 #include "llvm/IR/LLVMContext.h" 45 #include "llvm/IR/Module.h" 46 #include "llvm/Support/CallSite.h" 47 #include "llvm/Support/ConvertUTF.h" 48 #include "llvm/Support/ErrorHandling.h" 49 #include "llvm/Target/Mangler.h" 50 51 using namespace clang; 52 using namespace CodeGen; 53 54 static const char AnnotationSection[] = "llvm.metadata"; 55 56 static CGCXXABI &createCXXABI(CodeGenModule &CGM) { 57 switch (CGM.getTarget().getCXXABI().getKind()) { 58 case TargetCXXABI::GenericAArch64: 59 case TargetCXXABI::GenericARM: 60 case TargetCXXABI::iOS: 61 case TargetCXXABI::GenericItanium: 62 return *CreateItaniumCXXABI(CGM); 63 case TargetCXXABI::Microsoft: 64 return *CreateMicrosoftCXXABI(CGM); 65 } 66 67 llvm_unreachable("invalid C++ ABI kind"); 68 } 69 70 71 CodeGenModule::CodeGenModule(ASTContext &C, const CodeGenOptions &CGO, 72 llvm::Module &M, const llvm::DataLayout &TD, 73 DiagnosticsEngine &diags) 74 : Context(C), LangOpts(C.getLangOpts()), CodeGenOpts(CGO), TheModule(M), 75 Diags(diags), TheDataLayout(TD), Target(C.getTargetInfo()), 76 ABI(createCXXABI(*this)), VMContext(M.getContext()), TBAA(0), 77 TheTargetCodeGenInfo(0), Types(*this), VTables(*this), 78 ObjCRuntime(0), OpenCLRuntime(0), CUDARuntime(0), 79 DebugInfo(0), ARCData(0), NoObjCARCExceptionsMetadata(0), 80 RRData(0), CFConstantStringClassRef(0), 81 ConstantStringClassRef(0), NSConstantStringType(0), 82 NSConcreteGlobalBlock(0), NSConcreteStackBlock(0), 83 BlockObjectAssign(0), BlockObjectDispose(0), 84 BlockDescriptorType(0), GenericBlockLiteralType(0), 85 LifetimeStartFn(0), LifetimeEndFn(0), 86 SanitizerBlacklist(CGO.SanitizerBlacklistFile), 87 SanOpts(SanitizerBlacklist.isIn(M) ? 88 SanitizerOptions::Disabled : LangOpts.Sanitize) { 89 90 // Initialize the type cache. 91 llvm::LLVMContext &LLVMContext = M.getContext(); 92 VoidTy = llvm::Type::getVoidTy(LLVMContext); 93 Int8Ty = llvm::Type::getInt8Ty(LLVMContext); 94 Int16Ty = llvm::Type::getInt16Ty(LLVMContext); 95 Int32Ty = llvm::Type::getInt32Ty(LLVMContext); 96 Int64Ty = llvm::Type::getInt64Ty(LLVMContext); 97 FloatTy = llvm::Type::getFloatTy(LLVMContext); 98 DoubleTy = llvm::Type::getDoubleTy(LLVMContext); 99 PointerWidthInBits = C.getTargetInfo().getPointerWidth(0); 100 PointerAlignInBytes = 101 C.toCharUnitsFromBits(C.getTargetInfo().getPointerAlign(0)).getQuantity(); 102 IntTy = llvm::IntegerType::get(LLVMContext, C.getTargetInfo().getIntWidth()); 103 IntPtrTy = llvm::IntegerType::get(LLVMContext, PointerWidthInBits); 104 Int8PtrTy = Int8Ty->getPointerTo(0); 105 Int8PtrPtrTy = Int8PtrTy->getPointerTo(0); 106 107 RuntimeCC = getTargetCodeGenInfo().getABIInfo().getRuntimeCC(); 108 109 if (LangOpts.ObjC1) 110 createObjCRuntime(); 111 if (LangOpts.OpenCL) 112 createOpenCLRuntime(); 113 if (LangOpts.CUDA) 114 createCUDARuntime(); 115 116 // Enable TBAA unless it's suppressed. ThreadSanitizer needs TBAA even at O0. 117 if (SanOpts.Thread || 118 (!CodeGenOpts.RelaxedAliasing && CodeGenOpts.OptimizationLevel > 0)) 119 TBAA = new CodeGenTBAA(Context, VMContext, CodeGenOpts, getLangOpts(), 120 ABI.getMangleContext()); 121 122 // If debug info or coverage generation is enabled, create the CGDebugInfo 123 // object. 124 if (CodeGenOpts.getDebugInfo() != CodeGenOptions::NoDebugInfo || 125 CodeGenOpts.EmitGcovArcs || 126 CodeGenOpts.EmitGcovNotes) 127 DebugInfo = new CGDebugInfo(*this); 128 129 Block.GlobalUniqueCount = 0; 130 131 if (C.getLangOpts().ObjCAutoRefCount) 132 ARCData = new ARCEntrypoints(); 133 RRData = new RREntrypoints(); 134 } 135 136 CodeGenModule::~CodeGenModule() { 137 delete ObjCRuntime; 138 delete OpenCLRuntime; 139 delete CUDARuntime; 140 delete TheTargetCodeGenInfo; 141 delete &ABI; 142 delete TBAA; 143 delete DebugInfo; 144 delete ARCData; 145 delete RRData; 146 } 147 148 void CodeGenModule::createObjCRuntime() { 149 // This is just isGNUFamily(), but we want to force implementors of 150 // new ABIs to decide how best to do this. 151 switch (LangOpts.ObjCRuntime.getKind()) { 152 case ObjCRuntime::GNUstep: 153 case ObjCRuntime::GCC: 154 case ObjCRuntime::ObjFW: 155 ObjCRuntime = CreateGNUObjCRuntime(*this); 156 return; 157 158 case ObjCRuntime::FragileMacOSX: 159 case ObjCRuntime::MacOSX: 160 case ObjCRuntime::iOS: 161 ObjCRuntime = CreateMacObjCRuntime(*this); 162 return; 163 } 164 llvm_unreachable("bad runtime kind"); 165 } 166 167 void CodeGenModule::createOpenCLRuntime() { 168 OpenCLRuntime = new CGOpenCLRuntime(*this); 169 } 170 171 void CodeGenModule::createCUDARuntime() { 172 CUDARuntime = CreateNVCUDARuntime(*this); 173 } 174 175 void CodeGenModule::Release() { 176 EmitDeferred(); 177 EmitCXXGlobalInitFunc(); 178 EmitCXXGlobalDtorFunc(); 179 EmitCXXThreadLocalInitFunc(); 180 if (ObjCRuntime) 181 if (llvm::Function *ObjCInitFunction = ObjCRuntime->ModuleInitFunction()) 182 AddGlobalCtor(ObjCInitFunction); 183 EmitCtorList(GlobalCtors, "llvm.global_ctors"); 184 EmitCtorList(GlobalDtors, "llvm.global_dtors"); 185 EmitGlobalAnnotations(); 186 EmitStaticExternCAliases(); 187 EmitLLVMUsed(); 188 189 if (CodeGenOpts.Autolink && Context.getLangOpts().Modules) { 190 EmitModuleLinkOptions(); 191 } 192 193 SimplifyPersonality(); 194 195 if (getCodeGenOpts().EmitDeclMetadata) 196 EmitDeclMetadata(); 197 198 if (getCodeGenOpts().EmitGcovArcs || getCodeGenOpts().EmitGcovNotes) 199 EmitCoverageFile(); 200 201 if (DebugInfo) 202 DebugInfo->finalize(); 203 } 204 205 void CodeGenModule::UpdateCompletedType(const TagDecl *TD) { 206 // Make sure that this type is translated. 207 Types.UpdateCompletedType(TD); 208 } 209 210 llvm::MDNode *CodeGenModule::getTBAAInfo(QualType QTy) { 211 if (!TBAA) 212 return 0; 213 return TBAA->getTBAAInfo(QTy); 214 } 215 216 llvm::MDNode *CodeGenModule::getTBAAInfoForVTablePtr() { 217 if (!TBAA) 218 return 0; 219 return TBAA->getTBAAInfoForVTablePtr(); 220 } 221 222 llvm::MDNode *CodeGenModule::getTBAAStructInfo(QualType QTy) { 223 if (!TBAA) 224 return 0; 225 return TBAA->getTBAAStructInfo(QTy); 226 } 227 228 llvm::MDNode *CodeGenModule::getTBAAStructTypeInfo(QualType QTy) { 229 if (!TBAA) 230 return 0; 231 return TBAA->getTBAAStructTypeInfo(QTy); 232 } 233 234 llvm::MDNode *CodeGenModule::getTBAAStructTagInfo(QualType BaseTy, 235 llvm::MDNode *AccessN, 236 uint64_t O) { 237 if (!TBAA) 238 return 0; 239 return TBAA->getTBAAStructTagInfo(BaseTy, AccessN, O); 240 } 241 242 /// Decorate the instruction with a TBAA tag. For scalar TBAA, the tag 243 /// is the same as the type. For struct-path aware TBAA, the tag 244 /// is different from the type: base type, access type and offset. 245 /// When ConvertTypeToTag is true, we create a tag based on the scalar type. 246 void CodeGenModule::DecorateInstruction(llvm::Instruction *Inst, 247 llvm::MDNode *TBAAInfo, 248 bool ConvertTypeToTag) { 249 if (ConvertTypeToTag && TBAA && CodeGenOpts.StructPathTBAA) 250 Inst->setMetadata(llvm::LLVMContext::MD_tbaa, 251 TBAA->getTBAAScalarTagInfo(TBAAInfo)); 252 else 253 Inst->setMetadata(llvm::LLVMContext::MD_tbaa, TBAAInfo); 254 } 255 256 void CodeGenModule::Error(SourceLocation loc, StringRef error) { 257 unsigned diagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error, error); 258 getDiags().Report(Context.getFullLoc(loc), diagID); 259 } 260 261 /// ErrorUnsupported - Print out an error that codegen doesn't support the 262 /// specified stmt yet. 263 void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type, 264 bool OmitOnError) { 265 if (OmitOnError && getDiags().hasErrorOccurred()) 266 return; 267 unsigned DiagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error, 268 "cannot compile this %0 yet"); 269 std::string Msg = Type; 270 getDiags().Report(Context.getFullLoc(S->getLocStart()), DiagID) 271 << Msg << S->getSourceRange(); 272 } 273 274 /// ErrorUnsupported - Print out an error that codegen doesn't support the 275 /// specified decl yet. 276 void CodeGenModule::ErrorUnsupported(const Decl *D, const char *Type, 277 bool OmitOnError) { 278 if (OmitOnError && getDiags().hasErrorOccurred()) 279 return; 280 unsigned DiagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error, 281 "cannot compile this %0 yet"); 282 std::string Msg = Type; 283 getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID) << Msg; 284 } 285 286 llvm::ConstantInt *CodeGenModule::getSize(CharUnits size) { 287 return llvm::ConstantInt::get(SizeTy, size.getQuantity()); 288 } 289 290 void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV, 291 const NamedDecl *D) const { 292 // Internal definitions always have default visibility. 293 if (GV->hasLocalLinkage()) { 294 GV->setVisibility(llvm::GlobalValue::DefaultVisibility); 295 return; 296 } 297 298 // Set visibility for definitions. 299 LinkageInfo LV = D->getLinkageAndVisibility(); 300 if (LV.isVisibilityExplicit() || !GV->hasAvailableExternallyLinkage()) 301 GV->setVisibility(GetLLVMVisibility(LV.getVisibility())); 302 } 303 304 static llvm::GlobalVariable::ThreadLocalMode GetLLVMTLSModel(StringRef S) { 305 return llvm::StringSwitch<llvm::GlobalVariable::ThreadLocalMode>(S) 306 .Case("global-dynamic", llvm::GlobalVariable::GeneralDynamicTLSModel) 307 .Case("local-dynamic", llvm::GlobalVariable::LocalDynamicTLSModel) 308 .Case("initial-exec", llvm::GlobalVariable::InitialExecTLSModel) 309 .Case("local-exec", llvm::GlobalVariable::LocalExecTLSModel); 310 } 311 312 static llvm::GlobalVariable::ThreadLocalMode GetLLVMTLSModel( 313 CodeGenOptions::TLSModel M) { 314 switch (M) { 315 case CodeGenOptions::GeneralDynamicTLSModel: 316 return llvm::GlobalVariable::GeneralDynamicTLSModel; 317 case CodeGenOptions::LocalDynamicTLSModel: 318 return llvm::GlobalVariable::LocalDynamicTLSModel; 319 case CodeGenOptions::InitialExecTLSModel: 320 return llvm::GlobalVariable::InitialExecTLSModel; 321 case CodeGenOptions::LocalExecTLSModel: 322 return llvm::GlobalVariable::LocalExecTLSModel; 323 } 324 llvm_unreachable("Invalid TLS model!"); 325 } 326 327 void CodeGenModule::setTLSMode(llvm::GlobalVariable *GV, 328 const VarDecl &D) const { 329 assert(D.getTLSKind() && "setting TLS mode on non-TLS var!"); 330 331 llvm::GlobalVariable::ThreadLocalMode TLM; 332 TLM = GetLLVMTLSModel(CodeGenOpts.getDefaultTLSModel()); 333 334 // Override the TLS model if it is explicitly specified. 335 if (D.hasAttr<TLSModelAttr>()) { 336 const TLSModelAttr *Attr = D.getAttr<TLSModelAttr>(); 337 TLM = GetLLVMTLSModel(Attr->getModel()); 338 } 339 340 GV->setThreadLocalMode(TLM); 341 } 342 343 /// Set the symbol visibility of type information (vtable and RTTI) 344 /// associated with the given type. 345 void CodeGenModule::setTypeVisibility(llvm::GlobalValue *GV, 346 const CXXRecordDecl *RD, 347 TypeVisibilityKind TVK) const { 348 setGlobalVisibility(GV, RD); 349 350 if (!CodeGenOpts.HiddenWeakVTables) 351 return; 352 353 // We never want to drop the visibility for RTTI names. 354 if (TVK == TVK_ForRTTIName) 355 return; 356 357 // We want to drop the visibility to hidden for weak type symbols. 358 // This isn't possible if there might be unresolved references 359 // elsewhere that rely on this symbol being visible. 360 361 // This should be kept roughly in sync with setThunkVisibility 362 // in CGVTables.cpp. 363 364 // Preconditions. 365 if (GV->getLinkage() != llvm::GlobalVariable::LinkOnceODRLinkage || 366 GV->getVisibility() != llvm::GlobalVariable::DefaultVisibility) 367 return; 368 369 // Don't override an explicit visibility attribute. 370 if (RD->getExplicitVisibility(NamedDecl::VisibilityForType)) 371 return; 372 373 switch (RD->getTemplateSpecializationKind()) { 374 // We have to disable the optimization if this is an EI definition 375 // because there might be EI declarations in other shared objects. 376 case TSK_ExplicitInstantiationDefinition: 377 case TSK_ExplicitInstantiationDeclaration: 378 return; 379 380 // Every use of a non-template class's type information has to emit it. 381 case TSK_Undeclared: 382 break; 383 384 // In theory, implicit instantiations can ignore the possibility of 385 // an explicit instantiation declaration because there necessarily 386 // must be an EI definition somewhere with default visibility. In 387 // practice, it's possible to have an explicit instantiation for 388 // an arbitrary template class, and linkers aren't necessarily able 389 // to deal with mixed-visibility symbols. 390 case TSK_ExplicitSpecialization: 391 case TSK_ImplicitInstantiation: 392 return; 393 } 394 395 // If there's a key function, there may be translation units 396 // that don't have the key function's definition. But ignore 397 // this if we're emitting RTTI under -fno-rtti. 398 if (!(TVK != TVK_ForRTTI) || LangOpts.RTTI) { 399 // FIXME: what should we do if we "lose" the key function during 400 // the emission of the file? 401 if (Context.getCurrentKeyFunction(RD)) 402 return; 403 } 404 405 // Otherwise, drop the visibility to hidden. 406 GV->setVisibility(llvm::GlobalValue::HiddenVisibility); 407 GV->setUnnamedAddr(true); 408 } 409 410 StringRef CodeGenModule::getMangledName(GlobalDecl GD) { 411 const NamedDecl *ND = cast<NamedDecl>(GD.getDecl()); 412 413 StringRef &Str = MangledDeclNames[GD.getCanonicalDecl()]; 414 if (!Str.empty()) 415 return Str; 416 417 if (!getCXXABI().getMangleContext().shouldMangleDeclName(ND)) { 418 IdentifierInfo *II = ND->getIdentifier(); 419 assert(II && "Attempt to mangle unnamed decl."); 420 421 Str = II->getName(); 422 return Str; 423 } 424 425 SmallString<256> Buffer; 426 llvm::raw_svector_ostream Out(Buffer); 427 if (const CXXConstructorDecl *D = dyn_cast<CXXConstructorDecl>(ND)) 428 getCXXABI().getMangleContext().mangleCXXCtor(D, GD.getCtorType(), Out); 429 else if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(ND)) 430 getCXXABI().getMangleContext().mangleCXXDtor(D, GD.getDtorType(), Out); 431 else if (const BlockDecl *BD = dyn_cast<BlockDecl>(ND)) 432 getCXXABI().getMangleContext().mangleBlock(BD, Out, 433 dyn_cast_or_null<VarDecl>(initializedGlobalDecl.getDecl())); 434 else 435 getCXXABI().getMangleContext().mangleName(ND, Out); 436 437 // Allocate space for the mangled name. 438 Out.flush(); 439 size_t Length = Buffer.size(); 440 char *Name = MangledNamesAllocator.Allocate<char>(Length); 441 std::copy(Buffer.begin(), Buffer.end(), Name); 442 443 Str = StringRef(Name, Length); 444 445 return Str; 446 } 447 448 void CodeGenModule::getBlockMangledName(GlobalDecl GD, MangleBuffer &Buffer, 449 const BlockDecl *BD) { 450 MangleContext &MangleCtx = getCXXABI().getMangleContext(); 451 const Decl *D = GD.getDecl(); 452 llvm::raw_svector_ostream Out(Buffer.getBuffer()); 453 if (D == 0) 454 MangleCtx.mangleGlobalBlock(BD, 455 dyn_cast_or_null<VarDecl>(initializedGlobalDecl.getDecl()), Out); 456 else if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(D)) 457 MangleCtx.mangleCtorBlock(CD, GD.getCtorType(), BD, Out); 458 else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(D)) 459 MangleCtx.mangleDtorBlock(DD, GD.getDtorType(), BD, Out); 460 else 461 MangleCtx.mangleBlock(cast<DeclContext>(D), BD, Out); 462 } 463 464 llvm::GlobalValue *CodeGenModule::GetGlobalValue(StringRef Name) { 465 return getModule().getNamedValue(Name); 466 } 467 468 /// AddGlobalCtor - Add a function to the list that will be called before 469 /// main() runs. 470 void CodeGenModule::AddGlobalCtor(llvm::Function * Ctor, int Priority) { 471 // FIXME: Type coercion of void()* types. 472 GlobalCtors.push_back(std::make_pair(Ctor, Priority)); 473 } 474 475 /// AddGlobalDtor - Add a function to the list that will be called 476 /// when the module is unloaded. 477 void CodeGenModule::AddGlobalDtor(llvm::Function * Dtor, int Priority) { 478 // FIXME: Type coercion of void()* types. 479 GlobalDtors.push_back(std::make_pair(Dtor, Priority)); 480 } 481 482 void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) { 483 // Ctor function type is void()*. 484 llvm::FunctionType* CtorFTy = llvm::FunctionType::get(VoidTy, false); 485 llvm::Type *CtorPFTy = llvm::PointerType::getUnqual(CtorFTy); 486 487 // Get the type of a ctor entry, { i32, void ()* }. 488 llvm::StructType *CtorStructTy = 489 llvm::StructType::get(Int32Ty, llvm::PointerType::getUnqual(CtorFTy), NULL); 490 491 // Construct the constructor and destructor arrays. 492 SmallVector<llvm::Constant*, 8> Ctors; 493 for (CtorList::const_iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { 494 llvm::Constant *S[] = { 495 llvm::ConstantInt::get(Int32Ty, I->second, false), 496 llvm::ConstantExpr::getBitCast(I->first, CtorPFTy) 497 }; 498 Ctors.push_back(llvm::ConstantStruct::get(CtorStructTy, S)); 499 } 500 501 if (!Ctors.empty()) { 502 llvm::ArrayType *AT = llvm::ArrayType::get(CtorStructTy, Ctors.size()); 503 new llvm::GlobalVariable(TheModule, AT, false, 504 llvm::GlobalValue::AppendingLinkage, 505 llvm::ConstantArray::get(AT, Ctors), 506 GlobalName); 507 } 508 } 509 510 llvm::GlobalValue::LinkageTypes 511 CodeGenModule::getFunctionLinkage(const FunctionDecl *D) { 512 GVALinkage Linkage = getContext().GetGVALinkageForFunction(D); 513 514 if (Linkage == GVA_Internal) 515 return llvm::Function::InternalLinkage; 516 517 if (D->hasAttr<DLLExportAttr>()) 518 return llvm::Function::DLLExportLinkage; 519 520 if (D->hasAttr<WeakAttr>()) 521 return llvm::Function::WeakAnyLinkage; 522 523 // In C99 mode, 'inline' functions are guaranteed to have a strong 524 // definition somewhere else, so we can use available_externally linkage. 525 if (Linkage == GVA_C99Inline) 526 return llvm::Function::AvailableExternallyLinkage; 527 528 // Note that Apple's kernel linker doesn't support symbol 529 // coalescing, so we need to avoid linkonce and weak linkages there. 530 // Normally, this means we just map to internal, but for explicit 531 // instantiations we'll map to external. 532 533 // In C++, the compiler has to emit a definition in every translation unit 534 // that references the function. We should use linkonce_odr because 535 // a) if all references in this translation unit are optimized away, we 536 // don't need to codegen it. b) if the function persists, it needs to be 537 // merged with other definitions. c) C++ has the ODR, so we know the 538 // definition is dependable. 539 if (Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation) 540 return !Context.getLangOpts().AppleKext 541 ? llvm::Function::LinkOnceODRLinkage 542 : llvm::Function::InternalLinkage; 543 544 // An explicit instantiation of a template has weak linkage, since 545 // explicit instantiations can occur in multiple translation units 546 // and must all be equivalent. However, we are not allowed to 547 // throw away these explicit instantiations. 548 if (Linkage == GVA_ExplicitTemplateInstantiation) 549 return !Context.getLangOpts().AppleKext 550 ? llvm::Function::WeakODRLinkage 551 : llvm::Function::ExternalLinkage; 552 553 // Otherwise, we have strong external linkage. 554 assert(Linkage == GVA_StrongExternal); 555 return llvm::Function::ExternalLinkage; 556 } 557 558 559 /// SetFunctionDefinitionAttributes - Set attributes for a global. 560 /// 561 /// FIXME: This is currently only done for aliases and functions, but not for 562 /// variables (these details are set in EmitGlobalVarDefinition for variables). 563 void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D, 564 llvm::GlobalValue *GV) { 565 SetCommonAttributes(D, GV); 566 } 567 568 void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D, 569 const CGFunctionInfo &Info, 570 llvm::Function *F) { 571 unsigned CallingConv; 572 AttributeListType AttributeList; 573 ConstructAttributeList(Info, D, AttributeList, CallingConv, false); 574 F->setAttributes(llvm::AttributeSet::get(getLLVMContext(), AttributeList)); 575 F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv)); 576 } 577 578 /// Determines whether the language options require us to model 579 /// unwind exceptions. We treat -fexceptions as mandating this 580 /// except under the fragile ObjC ABI with only ObjC exceptions 581 /// enabled. This means, for example, that C with -fexceptions 582 /// enables this. 583 static bool hasUnwindExceptions(const LangOptions &LangOpts) { 584 // If exceptions are completely disabled, obviously this is false. 585 if (!LangOpts.Exceptions) return false; 586 587 // If C++ exceptions are enabled, this is true. 588 if (LangOpts.CXXExceptions) return true; 589 590 // If ObjC exceptions are enabled, this depends on the ABI. 591 if (LangOpts.ObjCExceptions) { 592 return LangOpts.ObjCRuntime.hasUnwindExceptions(); 593 } 594 595 return true; 596 } 597 598 void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D, 599 llvm::Function *F) { 600 if (CodeGenOpts.UnwindTables) 601 F->setHasUWTable(); 602 603 if (!hasUnwindExceptions(LangOpts)) 604 F->addFnAttr(llvm::Attribute::NoUnwind); 605 606 if (D->hasAttr<NakedAttr>()) { 607 // Naked implies noinline: we should not be inlining such functions. 608 F->addFnAttr(llvm::Attribute::Naked); 609 F->addFnAttr(llvm::Attribute::NoInline); 610 } 611 612 if (D->hasAttr<NoInlineAttr>()) 613 F->addFnAttr(llvm::Attribute::NoInline); 614 615 // (noinline wins over always_inline, and we can't specify both in IR) 616 if ((D->hasAttr<AlwaysInlineAttr>() || D->hasAttr<ForceInlineAttr>()) && 617 !F->getAttributes().hasAttribute(llvm::AttributeSet::FunctionIndex, 618 llvm::Attribute::NoInline)) 619 F->addFnAttr(llvm::Attribute::AlwaysInline); 620 621 // FIXME: Communicate hot and cold attributes to LLVM more directly. 622 if (D->hasAttr<ColdAttr>()) 623 F->addFnAttr(llvm::Attribute::OptimizeForSize); 624 625 if (D->hasAttr<MinSizeAttr>()) 626 F->addFnAttr(llvm::Attribute::MinSize); 627 628 if (isa<CXXConstructorDecl>(D) || isa<CXXDestructorDecl>(D)) 629 F->setUnnamedAddr(true); 630 631 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) 632 if (MD->isVirtual()) 633 F->setUnnamedAddr(true); 634 635 if (LangOpts.getStackProtector() == LangOptions::SSPOn) 636 F->addFnAttr(llvm::Attribute::StackProtect); 637 else if (LangOpts.getStackProtector() == LangOptions::SSPReq) 638 F->addFnAttr(llvm::Attribute::StackProtectReq); 639 640 // Add sanitizer attributes if function is not blacklisted. 641 if (!SanitizerBlacklist.isIn(*F)) { 642 // When AddressSanitizer is enabled, set SanitizeAddress attribute 643 // unless __attribute__((no_sanitize_address)) is used. 644 if (SanOpts.Address && !D->hasAttr<NoSanitizeAddressAttr>()) 645 F->addFnAttr(llvm::Attribute::SanitizeAddress); 646 // Same for ThreadSanitizer and __attribute__((no_sanitize_thread)) 647 if (SanOpts.Thread && !D->hasAttr<NoSanitizeThreadAttr>()) { 648 F->addFnAttr(llvm::Attribute::SanitizeThread); 649 } 650 // Same for MemorySanitizer and __attribute__((no_sanitize_memory)) 651 if (SanOpts.Memory && !D->hasAttr<NoSanitizeMemoryAttr>()) 652 F->addFnAttr(llvm::Attribute::SanitizeMemory); 653 } 654 655 unsigned alignment = D->getMaxAlignment() / Context.getCharWidth(); 656 if (alignment) 657 F->setAlignment(alignment); 658 659 // C++ ABI requires 2-byte alignment for member functions. 660 if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D)) 661 F->setAlignment(2); 662 } 663 664 void CodeGenModule::SetCommonAttributes(const Decl *D, 665 llvm::GlobalValue *GV) { 666 if (const NamedDecl *ND = dyn_cast<NamedDecl>(D)) 667 setGlobalVisibility(GV, ND); 668 else 669 GV->setVisibility(llvm::GlobalValue::DefaultVisibility); 670 671 if (D->hasAttr<UsedAttr>()) 672 AddUsedGlobal(GV); 673 674 if (const SectionAttr *SA = D->getAttr<SectionAttr>()) 675 GV->setSection(SA->getName()); 676 677 // Alias cannot have attributes. Filter them here. 678 if (!isa<llvm::GlobalAlias>(GV)) 679 getTargetCodeGenInfo().SetTargetAttributes(D, GV, *this); 680 } 681 682 void CodeGenModule::SetInternalFunctionAttributes(const Decl *D, 683 llvm::Function *F, 684 const CGFunctionInfo &FI) { 685 SetLLVMFunctionAttributes(D, FI, F); 686 SetLLVMFunctionAttributesForDefinition(D, F); 687 688 F->setLinkage(llvm::Function::InternalLinkage); 689 690 SetCommonAttributes(D, F); 691 } 692 693 void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, 694 llvm::Function *F, 695 bool IsIncompleteFunction) { 696 if (unsigned IID = F->getIntrinsicID()) { 697 // If this is an intrinsic function, set the function's attributes 698 // to the intrinsic's attributes. 699 F->setAttributes(llvm::Intrinsic::getAttributes(getLLVMContext(), 700 (llvm::Intrinsic::ID)IID)); 701 return; 702 } 703 704 const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); 705 706 if (!IsIncompleteFunction) 707 SetLLVMFunctionAttributes(FD, getTypes().arrangeGlobalDeclaration(GD), F); 708 709 // Only a few attributes are set on declarations; these may later be 710 // overridden by a definition. 711 712 if (FD->hasAttr<DLLImportAttr>()) { 713 F->setLinkage(llvm::Function::DLLImportLinkage); 714 } else if (FD->hasAttr<WeakAttr>() || 715 FD->isWeakImported()) { 716 // "extern_weak" is overloaded in LLVM; we probably should have 717 // separate linkage types for this. 718 F->setLinkage(llvm::Function::ExternalWeakLinkage); 719 } else { 720 F->setLinkage(llvm::Function::ExternalLinkage); 721 722 LinkageInfo LV = FD->getLinkageAndVisibility(); 723 if (LV.getLinkage() == ExternalLinkage && LV.isVisibilityExplicit()) { 724 F->setVisibility(GetLLVMVisibility(LV.getVisibility())); 725 } 726 } 727 728 if (const SectionAttr *SA = FD->getAttr<SectionAttr>()) 729 F->setSection(SA->getName()); 730 } 731 732 void CodeGenModule::AddUsedGlobal(llvm::GlobalValue *GV) { 733 assert(!GV->isDeclaration() && 734 "Only globals with definition can force usage."); 735 LLVMUsed.push_back(GV); 736 } 737 738 void CodeGenModule::EmitLLVMUsed() { 739 // Don't create llvm.used if there is no need. 740 if (LLVMUsed.empty()) 741 return; 742 743 // Convert LLVMUsed to what ConstantArray needs. 744 SmallVector<llvm::Constant*, 8> UsedArray; 745 UsedArray.resize(LLVMUsed.size()); 746 for (unsigned i = 0, e = LLVMUsed.size(); i != e; ++i) { 747 UsedArray[i] = 748 llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(&*LLVMUsed[i]), 749 Int8PtrTy); 750 } 751 752 if (UsedArray.empty()) 753 return; 754 llvm::ArrayType *ATy = llvm::ArrayType::get(Int8PtrTy, UsedArray.size()); 755 756 llvm::GlobalVariable *GV = 757 new llvm::GlobalVariable(getModule(), ATy, false, 758 llvm::GlobalValue::AppendingLinkage, 759 llvm::ConstantArray::get(ATy, UsedArray), 760 "llvm.used"); 761 762 GV->setSection("llvm.metadata"); 763 } 764 765 /// \brief Add link options implied by the given module, including modules 766 /// it depends on, using a postorder walk. 767 static void addLinkOptionsPostorder(llvm::LLVMContext &Context, 768 Module *Mod, 769 SmallVectorImpl<llvm::Value *> &Metadata, 770 llvm::SmallPtrSet<Module *, 16> &Visited) { 771 // Import this module's parent. 772 if (Mod->Parent && Visited.insert(Mod->Parent)) { 773 addLinkOptionsPostorder(Context, Mod->Parent, Metadata, Visited); 774 } 775 776 // Import this module's dependencies. 777 for (unsigned I = Mod->Imports.size(); I > 0; --I) { 778 if (Visited.insert(Mod->Imports[I-1])) 779 addLinkOptionsPostorder(Context, Mod->Imports[I-1], Metadata, Visited); 780 } 781 782 // Add linker options to link against the libraries/frameworks 783 // described by this module. 784 for (unsigned I = Mod->LinkLibraries.size(); I > 0; --I) { 785 // FIXME: -lfoo is Unix-centric and -framework Foo is Darwin-centric. 786 // We need to know more about the linker to know how to encode these 787 // options propertly. 788 789 // Link against a framework. 790 if (Mod->LinkLibraries[I-1].IsFramework) { 791 llvm::Value *Args[2] = { 792 llvm::MDString::get(Context, "-framework"), 793 llvm::MDString::get(Context, Mod->LinkLibraries[I-1].Library) 794 }; 795 796 Metadata.push_back(llvm::MDNode::get(Context, Args)); 797 continue; 798 } 799 800 // Link against a library. 801 llvm::Value *OptString 802 = llvm::MDString::get(Context, 803 "-l" + Mod->LinkLibraries[I-1].Library); 804 Metadata.push_back(llvm::MDNode::get(Context, OptString)); 805 } 806 } 807 808 void CodeGenModule::EmitModuleLinkOptions() { 809 // Collect the set of all of the modules we want to visit to emit link 810 // options, which is essentially the imported modules and all of their 811 // non-explicit child modules. 812 llvm::SetVector<clang::Module *> LinkModules; 813 llvm::SmallPtrSet<clang::Module *, 16> Visited; 814 SmallVector<clang::Module *, 16> Stack; 815 816 // Seed the stack with imported modules. 817 for (llvm::SetVector<clang::Module *>::iterator M = ImportedModules.begin(), 818 MEnd = ImportedModules.end(); 819 M != MEnd; ++M) { 820 if (Visited.insert(*M)) 821 Stack.push_back(*M); 822 } 823 824 // Find all of the modules to import, making a little effort to prune 825 // non-leaf modules. 826 while (!Stack.empty()) { 827 clang::Module *Mod = Stack.back(); 828 Stack.pop_back(); 829 830 bool AnyChildren = false; 831 832 // Visit the submodules of this module. 833 for (clang::Module::submodule_iterator Sub = Mod->submodule_begin(), 834 SubEnd = Mod->submodule_end(); 835 Sub != SubEnd; ++Sub) { 836 // Skip explicit children; they need to be explicitly imported to be 837 // linked against. 838 if ((*Sub)->IsExplicit) 839 continue; 840 841 if (Visited.insert(*Sub)) { 842 Stack.push_back(*Sub); 843 AnyChildren = true; 844 } 845 } 846 847 // We didn't find any children, so add this module to the list of 848 // modules to link against. 849 if (!AnyChildren) { 850 LinkModules.insert(Mod); 851 } 852 } 853 854 // Add link options for all of the imported modules in reverse topological 855 // order. 856 SmallVector<llvm::Value *, 16> MetadataArgs; 857 Visited.clear(); 858 for (llvm::SetVector<clang::Module *>::iterator M = LinkModules.begin(), 859 MEnd = LinkModules.end(); 860 M != MEnd; ++M) { 861 if (Visited.insert(*M)) 862 addLinkOptionsPostorder(getLLVMContext(), *M, MetadataArgs, Visited); 863 } 864 std::reverse(MetadataArgs.begin(), MetadataArgs.end()); 865 866 // Add the linker options metadata flag. 867 getModule().addModuleFlag(llvm::Module::AppendUnique, "Linker Options", 868 llvm::MDNode::get(getLLVMContext(), MetadataArgs)); 869 } 870 871 void CodeGenModule::EmitDeferred() { 872 // Emit code for any potentially referenced deferred decls. Since a 873 // previously unused static decl may become used during the generation of code 874 // for a static function, iterate until no changes are made. 875 876 while (true) { 877 if (!DeferredVTables.empty()) { 878 EmitDeferredVTables(); 879 880 // Emitting a v-table doesn't directly cause more v-tables to 881 // become deferred, although it can cause functions to be 882 // emitted that then need those v-tables. 883 assert(DeferredVTables.empty()); 884 } 885 886 // Stop if we're out of both deferred v-tables and deferred declarations. 887 if (DeferredDeclsToEmit.empty()) break; 888 889 GlobalDecl D = DeferredDeclsToEmit.back(); 890 DeferredDeclsToEmit.pop_back(); 891 892 // Check to see if we've already emitted this. This is necessary 893 // for a couple of reasons: first, decls can end up in the 894 // deferred-decls queue multiple times, and second, decls can end 895 // up with definitions in unusual ways (e.g. by an extern inline 896 // function acquiring a strong function redefinition). Just 897 // ignore these cases. 898 // 899 // TODO: That said, looking this up multiple times is very wasteful. 900 StringRef Name = getMangledName(D); 901 llvm::GlobalValue *CGRef = GetGlobalValue(Name); 902 assert(CGRef && "Deferred decl wasn't referenced?"); 903 904 if (!CGRef->isDeclaration()) 905 continue; 906 907 // GlobalAlias::isDeclaration() defers to the aliasee, but for our 908 // purposes an alias counts as a definition. 909 if (isa<llvm::GlobalAlias>(CGRef)) 910 continue; 911 912 // Otherwise, emit the definition and move on to the next one. 913 EmitGlobalDefinition(D); 914 } 915 } 916 917 void CodeGenModule::EmitGlobalAnnotations() { 918 if (Annotations.empty()) 919 return; 920 921 // Create a new global variable for the ConstantStruct in the Module. 922 llvm::Constant *Array = llvm::ConstantArray::get(llvm::ArrayType::get( 923 Annotations[0]->getType(), Annotations.size()), Annotations); 924 llvm::GlobalValue *gv = new llvm::GlobalVariable(getModule(), 925 Array->getType(), false, llvm::GlobalValue::AppendingLinkage, Array, 926 "llvm.global.annotations"); 927 gv->setSection(AnnotationSection); 928 } 929 930 llvm::Constant *CodeGenModule::EmitAnnotationString(StringRef Str) { 931 llvm::StringMap<llvm::Constant*>::iterator i = AnnotationStrings.find(Str); 932 if (i != AnnotationStrings.end()) 933 return i->second; 934 935 // Not found yet, create a new global. 936 llvm::Constant *s = llvm::ConstantDataArray::getString(getLLVMContext(), Str); 937 llvm::GlobalValue *gv = new llvm::GlobalVariable(getModule(), s->getType(), 938 true, llvm::GlobalValue::PrivateLinkage, s, ".str"); 939 gv->setSection(AnnotationSection); 940 gv->setUnnamedAddr(true); 941 AnnotationStrings[Str] = gv; 942 return gv; 943 } 944 945 llvm::Constant *CodeGenModule::EmitAnnotationUnit(SourceLocation Loc) { 946 SourceManager &SM = getContext().getSourceManager(); 947 PresumedLoc PLoc = SM.getPresumedLoc(Loc); 948 if (PLoc.isValid()) 949 return EmitAnnotationString(PLoc.getFilename()); 950 return EmitAnnotationString(SM.getBufferName(Loc)); 951 } 952 953 llvm::Constant *CodeGenModule::EmitAnnotationLineNo(SourceLocation L) { 954 SourceManager &SM = getContext().getSourceManager(); 955 PresumedLoc PLoc = SM.getPresumedLoc(L); 956 unsigned LineNo = PLoc.isValid() ? PLoc.getLine() : 957 SM.getExpansionLineNumber(L); 958 return llvm::ConstantInt::get(Int32Ty, LineNo); 959 } 960 961 llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV, 962 const AnnotateAttr *AA, 963 SourceLocation L) { 964 // Get the globals for file name, annotation, and the line number. 965 llvm::Constant *AnnoGV = EmitAnnotationString(AA->getAnnotation()), 966 *UnitGV = EmitAnnotationUnit(L), 967 *LineNoCst = EmitAnnotationLineNo(L); 968 969 // Create the ConstantStruct for the global annotation. 970 llvm::Constant *Fields[4] = { 971 llvm::ConstantExpr::getBitCast(GV, Int8PtrTy), 972 llvm::ConstantExpr::getBitCast(AnnoGV, Int8PtrTy), 973 llvm::ConstantExpr::getBitCast(UnitGV, Int8PtrTy), 974 LineNoCst 975 }; 976 return llvm::ConstantStruct::getAnon(Fields); 977 } 978 979 void CodeGenModule::AddGlobalAnnotations(const ValueDecl *D, 980 llvm::GlobalValue *GV) { 981 assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute"); 982 // Get the struct elements for these annotations. 983 for (specific_attr_iterator<AnnotateAttr> 984 ai = D->specific_attr_begin<AnnotateAttr>(), 985 ae = D->specific_attr_end<AnnotateAttr>(); ai != ae; ++ai) 986 Annotations.push_back(EmitAnnotateAttr(GV, *ai, D->getLocation())); 987 } 988 989 bool CodeGenModule::MayDeferGeneration(const ValueDecl *Global) { 990 // Never defer when EmitAllDecls is specified. 991 if (LangOpts.EmitAllDecls) 992 return false; 993 994 return !getContext().DeclMustBeEmitted(Global); 995 } 996 997 llvm::Constant *CodeGenModule::GetAddrOfUuidDescriptor( 998 const CXXUuidofExpr* E) { 999 // Sema has verified that IIDSource has a __declspec(uuid()), and that its 1000 // well-formed. 1001 StringRef Uuid; 1002 if (E->isTypeOperand()) 1003 Uuid = CXXUuidofExpr::GetUuidAttrOfType(E->getTypeOperand())->getGuid(); 1004 else { 1005 // Special case: __uuidof(0) means an all-zero GUID. 1006 Expr *Op = E->getExprOperand(); 1007 if (!Op->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull)) 1008 Uuid = CXXUuidofExpr::GetUuidAttrOfType(Op->getType())->getGuid(); 1009 else 1010 Uuid = "00000000-0000-0000-0000-000000000000"; 1011 } 1012 std::string Name = "__uuid_" + Uuid.str(); 1013 1014 // Look for an existing global. 1015 if (llvm::GlobalVariable *GV = getModule().getNamedGlobal(Name)) 1016 return GV; 1017 1018 llvm::Constant *Init = EmitUuidofInitializer(Uuid, E->getType()); 1019 assert(Init && "failed to initialize as constant"); 1020 1021 // GUIDs are assumed to be 16 bytes, spread over 4-2-2-8 bytes. However, the 1022 // first field is declared as "long", which for many targets is 8 bytes. 1023 // Those architectures are not supported. (With the MS abi, long is always 4 1024 // bytes.) 1025 llvm::Type *GuidType = getTypes().ConvertType(E->getType()); 1026 if (Init->getType() != GuidType) { 1027 DiagnosticsEngine &Diags = getDiags(); 1028 unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error, 1029 "__uuidof codegen is not supported on this architecture"); 1030 Diags.Report(E->getExprLoc(), DiagID) << E->getSourceRange(); 1031 Init = llvm::UndefValue::get(GuidType); 1032 } 1033 1034 llvm::GlobalVariable *GV = new llvm::GlobalVariable(getModule(), GuidType, 1035 /*isConstant=*/true, llvm::GlobalValue::PrivateLinkage, Init, Name); 1036 GV->setUnnamedAddr(true); 1037 return GV; 1038 } 1039 1040 llvm::Constant *CodeGenModule::GetWeakRefReference(const ValueDecl *VD) { 1041 const AliasAttr *AA = VD->getAttr<AliasAttr>(); 1042 assert(AA && "No alias?"); 1043 1044 llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType()); 1045 1046 // See if there is already something with the target's name in the module. 1047 llvm::GlobalValue *Entry = GetGlobalValue(AA->getAliasee()); 1048 if (Entry) { 1049 unsigned AS = getContext().getTargetAddressSpace(VD->getType()); 1050 return llvm::ConstantExpr::getBitCast(Entry, DeclTy->getPointerTo(AS)); 1051 } 1052 1053 llvm::Constant *Aliasee; 1054 if (isa<llvm::FunctionType>(DeclTy)) 1055 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, 1056 GlobalDecl(cast<FunctionDecl>(VD)), 1057 /*ForVTable=*/false); 1058 else 1059 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 1060 llvm::PointerType::getUnqual(DeclTy), 0); 1061 1062 llvm::GlobalValue* F = cast<llvm::GlobalValue>(Aliasee); 1063 F->setLinkage(llvm::Function::ExternalWeakLinkage); 1064 WeakRefReferences.insert(F); 1065 1066 return Aliasee; 1067 } 1068 1069 void CodeGenModule::EmitGlobal(GlobalDecl GD) { 1070 const ValueDecl *Global = cast<ValueDecl>(GD.getDecl()); 1071 1072 // Weak references don't produce any output by themselves. 1073 if (Global->hasAttr<WeakRefAttr>()) 1074 return; 1075 1076 // If this is an alias definition (which otherwise looks like a declaration) 1077 // emit it now. 1078 if (Global->hasAttr<AliasAttr>()) 1079 return EmitAliasDefinition(GD); 1080 1081 // If this is CUDA, be selective about which declarations we emit. 1082 if (LangOpts.CUDA) { 1083 if (CodeGenOpts.CUDAIsDevice) { 1084 if (!Global->hasAttr<CUDADeviceAttr>() && 1085 !Global->hasAttr<CUDAGlobalAttr>() && 1086 !Global->hasAttr<CUDAConstantAttr>() && 1087 !Global->hasAttr<CUDASharedAttr>()) 1088 return; 1089 } else { 1090 if (!Global->hasAttr<CUDAHostAttr>() && ( 1091 Global->hasAttr<CUDADeviceAttr>() || 1092 Global->hasAttr<CUDAConstantAttr>() || 1093 Global->hasAttr<CUDASharedAttr>())) 1094 return; 1095 } 1096 } 1097 1098 // Ignore declarations, they will be emitted on their first use. 1099 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) { 1100 // Forward declarations are emitted lazily on first use. 1101 if (!FD->doesThisDeclarationHaveABody()) { 1102 if (!FD->doesDeclarationForceExternallyVisibleDefinition()) 1103 return; 1104 1105 const FunctionDecl *InlineDefinition = 0; 1106 FD->getBody(InlineDefinition); 1107 1108 StringRef MangledName = getMangledName(GD); 1109 DeferredDecls.erase(MangledName); 1110 EmitGlobalDefinition(InlineDefinition); 1111 return; 1112 } 1113 } else { 1114 const VarDecl *VD = cast<VarDecl>(Global); 1115 assert(VD->isFileVarDecl() && "Cannot emit local var decl as global."); 1116 1117 if (VD->isThisDeclarationADefinition() != VarDecl::Definition) 1118 return; 1119 } 1120 1121 // Defer code generation when possible if this is a static definition, inline 1122 // function etc. These we only want to emit if they are used. 1123 if (!MayDeferGeneration(Global)) { 1124 // Emit the definition if it can't be deferred. 1125 EmitGlobalDefinition(GD); 1126 return; 1127 } 1128 1129 // If we're deferring emission of a C++ variable with an 1130 // initializer, remember the order in which it appeared in the file. 1131 if (getLangOpts().CPlusPlus && isa<VarDecl>(Global) && 1132 cast<VarDecl>(Global)->hasInit()) { 1133 DelayedCXXInitPosition[Global] = CXXGlobalInits.size(); 1134 CXXGlobalInits.push_back(0); 1135 } 1136 1137 // If the value has already been used, add it directly to the 1138 // DeferredDeclsToEmit list. 1139 StringRef MangledName = getMangledName(GD); 1140 if (GetGlobalValue(MangledName)) 1141 DeferredDeclsToEmit.push_back(GD); 1142 else { 1143 // Otherwise, remember that we saw a deferred decl with this name. The 1144 // first use of the mangled name will cause it to move into 1145 // DeferredDeclsToEmit. 1146 DeferredDecls[MangledName] = GD; 1147 } 1148 } 1149 1150 namespace { 1151 struct FunctionIsDirectlyRecursive : 1152 public RecursiveASTVisitor<FunctionIsDirectlyRecursive> { 1153 const StringRef Name; 1154 const Builtin::Context &BI; 1155 bool Result; 1156 FunctionIsDirectlyRecursive(StringRef N, const Builtin::Context &C) : 1157 Name(N), BI(C), Result(false) { 1158 } 1159 typedef RecursiveASTVisitor<FunctionIsDirectlyRecursive> Base; 1160 1161 bool TraverseCallExpr(CallExpr *E) { 1162 const FunctionDecl *FD = E->getDirectCallee(); 1163 if (!FD) 1164 return true; 1165 AsmLabelAttr *Attr = FD->getAttr<AsmLabelAttr>(); 1166 if (Attr && Name == Attr->getLabel()) { 1167 Result = true; 1168 return false; 1169 } 1170 unsigned BuiltinID = FD->getBuiltinID(); 1171 if (!BuiltinID) 1172 return true; 1173 StringRef BuiltinName = BI.GetName(BuiltinID); 1174 if (BuiltinName.startswith("__builtin_") && 1175 Name == BuiltinName.slice(strlen("__builtin_"), StringRef::npos)) { 1176 Result = true; 1177 return false; 1178 } 1179 return true; 1180 } 1181 }; 1182 } 1183 1184 // isTriviallyRecursive - Check if this function calls another 1185 // decl that, because of the asm attribute or the other decl being a builtin, 1186 // ends up pointing to itself. 1187 bool 1188 CodeGenModule::isTriviallyRecursive(const FunctionDecl *FD) { 1189 StringRef Name; 1190 if (getCXXABI().getMangleContext().shouldMangleDeclName(FD)) { 1191 // asm labels are a special kind of mangling we have to support. 1192 AsmLabelAttr *Attr = FD->getAttr<AsmLabelAttr>(); 1193 if (!Attr) 1194 return false; 1195 Name = Attr->getLabel(); 1196 } else { 1197 Name = FD->getName(); 1198 } 1199 1200 FunctionIsDirectlyRecursive Walker(Name, Context.BuiltinInfo); 1201 Walker.TraverseFunctionDecl(const_cast<FunctionDecl*>(FD)); 1202 return Walker.Result; 1203 } 1204 1205 bool 1206 CodeGenModule::shouldEmitFunction(const FunctionDecl *F) { 1207 if (getFunctionLinkage(F) != llvm::Function::AvailableExternallyLinkage) 1208 return true; 1209 if (CodeGenOpts.OptimizationLevel == 0 && 1210 !F->hasAttr<AlwaysInlineAttr>() && !F->hasAttr<ForceInlineAttr>()) 1211 return false; 1212 // PR9614. Avoid cases where the source code is lying to us. An available 1213 // externally function should have an equivalent function somewhere else, 1214 // but a function that calls itself is clearly not equivalent to the real 1215 // implementation. 1216 // This happens in glibc's btowc and in some configure checks. 1217 return !isTriviallyRecursive(F); 1218 } 1219 1220 void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) { 1221 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 1222 1223 PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(), 1224 Context.getSourceManager(), 1225 "Generating code for declaration"); 1226 1227 if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) { 1228 // At -O0, don't generate IR for functions with available_externally 1229 // linkage. 1230 if (!shouldEmitFunction(Function)) 1231 return; 1232 1233 if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) { 1234 // Make sure to emit the definition(s) before we emit the thunks. 1235 // This is necessary for the generation of certain thunks. 1236 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Method)) 1237 EmitCXXConstructor(CD, GD.getCtorType()); 1238 else if (const CXXDestructorDecl *DD =dyn_cast<CXXDestructorDecl>(Method)) 1239 EmitCXXDestructor(DD, GD.getDtorType()); 1240 else 1241 EmitGlobalFunctionDefinition(GD); 1242 1243 if (Method->isVirtual()) 1244 getVTables().EmitThunks(GD); 1245 1246 return; 1247 } 1248 1249 return EmitGlobalFunctionDefinition(GD); 1250 } 1251 1252 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 1253 return EmitGlobalVarDefinition(VD); 1254 1255 llvm_unreachable("Invalid argument to EmitGlobalDefinition()"); 1256 } 1257 1258 /// GetOrCreateLLVMFunction - If the specified mangled name is not in the 1259 /// module, create and return an llvm Function with the specified type. If there 1260 /// is something in the module with the specified name, return it potentially 1261 /// bitcasted to the right type. 1262 /// 1263 /// If D is non-null, it specifies a decl that correspond to this. This is used 1264 /// to set the attributes on the function when it is first created. 1265 llvm::Constant * 1266 CodeGenModule::GetOrCreateLLVMFunction(StringRef MangledName, 1267 llvm::Type *Ty, 1268 GlobalDecl D, bool ForVTable, 1269 llvm::AttributeSet ExtraAttrs) { 1270 // Lookup the entry, lazily creating it if necessary. 1271 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 1272 if (Entry) { 1273 if (WeakRefReferences.erase(Entry)) { 1274 const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl()); 1275 if (FD && !FD->hasAttr<WeakAttr>()) 1276 Entry->setLinkage(llvm::Function::ExternalLinkage); 1277 } 1278 1279 if (Entry->getType()->getElementType() == Ty) 1280 return Entry; 1281 1282 // Make sure the result is of the correct type. 1283 return llvm::ConstantExpr::getBitCast(Entry, Ty->getPointerTo()); 1284 } 1285 1286 // This function doesn't have a complete type (for example, the return 1287 // type is an incomplete struct). Use a fake type instead, and make 1288 // sure not to try to set attributes. 1289 bool IsIncompleteFunction = false; 1290 1291 llvm::FunctionType *FTy; 1292 if (isa<llvm::FunctionType>(Ty)) { 1293 FTy = cast<llvm::FunctionType>(Ty); 1294 } else { 1295 FTy = llvm::FunctionType::get(VoidTy, false); 1296 IsIncompleteFunction = true; 1297 } 1298 1299 llvm::Function *F = llvm::Function::Create(FTy, 1300 llvm::Function::ExternalLinkage, 1301 MangledName, &getModule()); 1302 assert(F->getName() == MangledName && "name was uniqued!"); 1303 if (D.getDecl()) 1304 SetFunctionAttributes(D, F, IsIncompleteFunction); 1305 if (ExtraAttrs.hasAttributes(llvm::AttributeSet::FunctionIndex)) { 1306 llvm::AttrBuilder B(ExtraAttrs, llvm::AttributeSet::FunctionIndex); 1307 F->addAttributes(llvm::AttributeSet::FunctionIndex, 1308 llvm::AttributeSet::get(VMContext, 1309 llvm::AttributeSet::FunctionIndex, 1310 B)); 1311 } 1312 1313 // This is the first use or definition of a mangled name. If there is a 1314 // deferred decl with this name, remember that we need to emit it at the end 1315 // of the file. 1316 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 1317 if (DDI != DeferredDecls.end()) { 1318 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 1319 // list, and remove it from DeferredDecls (since we don't need it anymore). 1320 DeferredDeclsToEmit.push_back(DDI->second); 1321 DeferredDecls.erase(DDI); 1322 1323 // Otherwise, there are cases we have to worry about where we're 1324 // using a declaration for which we must emit a definition but where 1325 // we might not find a top-level definition: 1326 // - member functions defined inline in their classes 1327 // - friend functions defined inline in some class 1328 // - special member functions with implicit definitions 1329 // If we ever change our AST traversal to walk into class methods, 1330 // this will be unnecessary. 1331 // 1332 // We also don't emit a definition for a function if it's going to be an entry 1333 // in a vtable, unless it's already marked as used. 1334 } else if (getLangOpts().CPlusPlus && D.getDecl()) { 1335 // Look for a declaration that's lexically in a record. 1336 const FunctionDecl *FD = cast<FunctionDecl>(D.getDecl()); 1337 FD = FD->getMostRecentDecl(); 1338 do { 1339 if (isa<CXXRecordDecl>(FD->getLexicalDeclContext())) { 1340 if (FD->isImplicit() && !ForVTable) { 1341 assert(FD->isUsed() && "Sema didn't mark implicit function as used!"); 1342 DeferredDeclsToEmit.push_back(D.getWithDecl(FD)); 1343 break; 1344 } else if (FD->doesThisDeclarationHaveABody()) { 1345 DeferredDeclsToEmit.push_back(D.getWithDecl(FD)); 1346 break; 1347 } 1348 } 1349 FD = FD->getPreviousDecl(); 1350 } while (FD); 1351 } 1352 1353 // Make sure the result is of the requested type. 1354 if (!IsIncompleteFunction) { 1355 assert(F->getType()->getElementType() == Ty); 1356 return F; 1357 } 1358 1359 llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 1360 return llvm::ConstantExpr::getBitCast(F, PTy); 1361 } 1362 1363 /// GetAddrOfFunction - Return the address of the given function. If Ty is 1364 /// non-null, then this function will use the specified type if it has to 1365 /// create it (this occurs when we see a definition of the function). 1366 llvm::Constant *CodeGenModule::GetAddrOfFunction(GlobalDecl GD, 1367 llvm::Type *Ty, 1368 bool ForVTable) { 1369 // If there was no specific requested type, just convert it now. 1370 if (!Ty) 1371 Ty = getTypes().ConvertType(cast<ValueDecl>(GD.getDecl())->getType()); 1372 1373 StringRef MangledName = getMangledName(GD); 1374 return GetOrCreateLLVMFunction(MangledName, Ty, GD, ForVTable); 1375 } 1376 1377 /// CreateRuntimeFunction - Create a new runtime function with the specified 1378 /// type and name. 1379 llvm::Constant * 1380 CodeGenModule::CreateRuntimeFunction(llvm::FunctionType *FTy, 1381 StringRef Name, 1382 llvm::AttributeSet ExtraAttrs) { 1383 llvm::Constant *C 1384 = GetOrCreateLLVMFunction(Name, FTy, GlobalDecl(), /*ForVTable=*/false, 1385 ExtraAttrs); 1386 if (llvm::Function *F = dyn_cast<llvm::Function>(C)) 1387 if (F->empty()) 1388 F->setCallingConv(getRuntimeCC()); 1389 return C; 1390 } 1391 1392 /// isTypeConstant - Determine whether an object of this type can be emitted 1393 /// as a constant. 1394 /// 1395 /// If ExcludeCtor is true, the duration when the object's constructor runs 1396 /// will not be considered. The caller will need to verify that the object is 1397 /// not written to during its construction. 1398 bool CodeGenModule::isTypeConstant(QualType Ty, bool ExcludeCtor) { 1399 if (!Ty.isConstant(Context) && !Ty->isReferenceType()) 1400 return false; 1401 1402 if (Context.getLangOpts().CPlusPlus) { 1403 if (const CXXRecordDecl *Record 1404 = Context.getBaseElementType(Ty)->getAsCXXRecordDecl()) 1405 return ExcludeCtor && !Record->hasMutableFields() && 1406 Record->hasTrivialDestructor(); 1407 } 1408 1409 return true; 1410 } 1411 1412 /// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module, 1413 /// create and return an llvm GlobalVariable with the specified type. If there 1414 /// is something in the module with the specified name, return it potentially 1415 /// bitcasted to the right type. 1416 /// 1417 /// If D is non-null, it specifies a decl that correspond to this. This is used 1418 /// to set the attributes on the global when it is first created. 1419 llvm::Constant * 1420 CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName, 1421 llvm::PointerType *Ty, 1422 const VarDecl *D, 1423 bool UnnamedAddr) { 1424 // Lookup the entry, lazily creating it if necessary. 1425 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 1426 if (Entry) { 1427 if (WeakRefReferences.erase(Entry)) { 1428 if (D && !D->hasAttr<WeakAttr>()) 1429 Entry->setLinkage(llvm::Function::ExternalLinkage); 1430 } 1431 1432 if (UnnamedAddr) 1433 Entry->setUnnamedAddr(true); 1434 1435 if (Entry->getType() == Ty) 1436 return Entry; 1437 1438 // Make sure the result is of the correct type. 1439 return llvm::ConstantExpr::getBitCast(Entry, Ty); 1440 } 1441 1442 // This is the first use or definition of a mangled name. If there is a 1443 // deferred decl with this name, remember that we need to emit it at the end 1444 // of the file. 1445 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 1446 if (DDI != DeferredDecls.end()) { 1447 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 1448 // list, and remove it from DeferredDecls (since we don't need it anymore). 1449 DeferredDeclsToEmit.push_back(DDI->second); 1450 DeferredDecls.erase(DDI); 1451 } 1452 1453 unsigned AddrSpace = GetGlobalVarAddressSpace(D, Ty->getAddressSpace()); 1454 llvm::GlobalVariable *GV = 1455 new llvm::GlobalVariable(getModule(), Ty->getElementType(), false, 1456 llvm::GlobalValue::ExternalLinkage, 1457 0, MangledName, 0, 1458 llvm::GlobalVariable::NotThreadLocal, AddrSpace); 1459 1460 // Handle things which are present even on external declarations. 1461 if (D) { 1462 // FIXME: This code is overly simple and should be merged with other global 1463 // handling. 1464 GV->setConstant(isTypeConstant(D->getType(), false)); 1465 1466 // Set linkage and visibility in case we never see a definition. 1467 LinkageInfo LV = D->getLinkageAndVisibility(); 1468 if (LV.getLinkage() != ExternalLinkage) { 1469 // Don't set internal linkage on declarations. 1470 } else { 1471 if (D->hasAttr<DLLImportAttr>()) 1472 GV->setLinkage(llvm::GlobalValue::DLLImportLinkage); 1473 else if (D->hasAttr<WeakAttr>() || D->isWeakImported()) 1474 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage); 1475 1476 // Set visibility on a declaration only if it's explicit. 1477 if (LV.isVisibilityExplicit()) 1478 GV->setVisibility(GetLLVMVisibility(LV.getVisibility())); 1479 } 1480 1481 if (D->getTLSKind()) { 1482 if (D->getTLSKind() == VarDecl::TLS_Dynamic) 1483 CXXThreadLocals.push_back(std::make_pair(D, GV)); 1484 setTLSMode(GV, *D); 1485 } 1486 } 1487 1488 if (AddrSpace != Ty->getAddressSpace()) 1489 return llvm::ConstantExpr::getBitCast(GV, Ty); 1490 else 1491 return GV; 1492 } 1493 1494 1495 llvm::GlobalVariable * 1496 CodeGenModule::CreateOrReplaceCXXRuntimeVariable(StringRef Name, 1497 llvm::Type *Ty, 1498 llvm::GlobalValue::LinkageTypes Linkage) { 1499 llvm::GlobalVariable *GV = getModule().getNamedGlobal(Name); 1500 llvm::GlobalVariable *OldGV = 0; 1501 1502 1503 if (GV) { 1504 // Check if the variable has the right type. 1505 if (GV->getType()->getElementType() == Ty) 1506 return GV; 1507 1508 // Because C++ name mangling, the only way we can end up with an already 1509 // existing global with the same name is if it has been declared extern "C". 1510 assert(GV->isDeclaration() && "Declaration has wrong type!"); 1511 OldGV = GV; 1512 } 1513 1514 // Create a new variable. 1515 GV = new llvm::GlobalVariable(getModule(), Ty, /*isConstant=*/true, 1516 Linkage, 0, Name); 1517 1518 if (OldGV) { 1519 // Replace occurrences of the old variable if needed. 1520 GV->takeName(OldGV); 1521 1522 if (!OldGV->use_empty()) { 1523 llvm::Constant *NewPtrForOldDecl = 1524 llvm::ConstantExpr::getBitCast(GV, OldGV->getType()); 1525 OldGV->replaceAllUsesWith(NewPtrForOldDecl); 1526 } 1527 1528 OldGV->eraseFromParent(); 1529 } 1530 1531 return GV; 1532 } 1533 1534 /// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the 1535 /// given global variable. If Ty is non-null and if the global doesn't exist, 1536 /// then it will be created with the specified type instead of whatever the 1537 /// normal requested type would be. 1538 llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D, 1539 llvm::Type *Ty) { 1540 assert(D->hasGlobalStorage() && "Not a global variable"); 1541 QualType ASTTy = D->getType(); 1542 if (Ty == 0) 1543 Ty = getTypes().ConvertTypeForMem(ASTTy); 1544 1545 llvm::PointerType *PTy = 1546 llvm::PointerType::get(Ty, getContext().getTargetAddressSpace(ASTTy)); 1547 1548 StringRef MangledName = getMangledName(D); 1549 return GetOrCreateLLVMGlobal(MangledName, PTy, D); 1550 } 1551 1552 /// CreateRuntimeVariable - Create a new runtime global variable with the 1553 /// specified type and name. 1554 llvm::Constant * 1555 CodeGenModule::CreateRuntimeVariable(llvm::Type *Ty, 1556 StringRef Name) { 1557 return GetOrCreateLLVMGlobal(Name, llvm::PointerType::getUnqual(Ty), 0, 1558 true); 1559 } 1560 1561 void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) { 1562 assert(!D->getInit() && "Cannot emit definite definitions here!"); 1563 1564 if (MayDeferGeneration(D)) { 1565 // If we have not seen a reference to this variable yet, place it 1566 // into the deferred declarations table to be emitted if needed 1567 // later. 1568 StringRef MangledName = getMangledName(D); 1569 if (!GetGlobalValue(MangledName)) { 1570 DeferredDecls[MangledName] = D; 1571 return; 1572 } 1573 } 1574 1575 // The tentative definition is the only definition. 1576 EmitGlobalVarDefinition(D); 1577 } 1578 1579 CharUnits CodeGenModule::GetTargetTypeStoreSize(llvm::Type *Ty) const { 1580 return Context.toCharUnitsFromBits( 1581 TheDataLayout.getTypeStoreSizeInBits(Ty)); 1582 } 1583 1584 llvm::Constant * 1585 CodeGenModule::MaybeEmitGlobalStdInitializerListInitializer(const VarDecl *D, 1586 const Expr *rawInit) { 1587 ArrayRef<ExprWithCleanups::CleanupObject> cleanups; 1588 if (const ExprWithCleanups *withCleanups = 1589 dyn_cast<ExprWithCleanups>(rawInit)) { 1590 cleanups = withCleanups->getObjects(); 1591 rawInit = withCleanups->getSubExpr(); 1592 } 1593 1594 const InitListExpr *init = dyn_cast<InitListExpr>(rawInit); 1595 if (!init || !init->initializesStdInitializerList() || 1596 init->getNumInits() == 0) 1597 return 0; 1598 1599 ASTContext &ctx = getContext(); 1600 unsigned numInits = init->getNumInits(); 1601 // FIXME: This check is here because we would otherwise silently miscompile 1602 // nested global std::initializer_lists. Better would be to have a real 1603 // implementation. 1604 for (unsigned i = 0; i < numInits; ++i) { 1605 const InitListExpr *inner = dyn_cast<InitListExpr>(init->getInit(i)); 1606 if (inner && inner->initializesStdInitializerList()) { 1607 ErrorUnsupported(inner, "nested global std::initializer_list"); 1608 return 0; 1609 } 1610 } 1611 1612 // Synthesize a fake VarDecl for the array and initialize that. 1613 QualType elementType = init->getInit(0)->getType(); 1614 llvm::APInt numElements(ctx.getTypeSize(ctx.getSizeType()), numInits); 1615 QualType arrayType = ctx.getConstantArrayType(elementType, numElements, 1616 ArrayType::Normal, 0); 1617 1618 IdentifierInfo *name = &ctx.Idents.get(D->getNameAsString() + "__initlist"); 1619 TypeSourceInfo *sourceInfo = ctx.getTrivialTypeSourceInfo( 1620 arrayType, D->getLocation()); 1621 VarDecl *backingArray = VarDecl::Create(ctx, const_cast<DeclContext*>( 1622 D->getDeclContext()), 1623 D->getLocStart(), D->getLocation(), 1624 name, arrayType, sourceInfo, 1625 SC_Static); 1626 backingArray->setTSCSpec(D->getTSCSpec()); 1627 1628 // Now clone the InitListExpr to initialize the array instead. 1629 // Incredible hack: we want to use the existing InitListExpr here, so we need 1630 // to tell it that it no longer initializes a std::initializer_list. 1631 ArrayRef<Expr*> Inits(const_cast<InitListExpr*>(init)->getInits(), 1632 init->getNumInits()); 1633 Expr *arrayInit = new (ctx) InitListExpr(ctx, init->getLBraceLoc(), Inits, 1634 init->getRBraceLoc()); 1635 arrayInit->setType(arrayType); 1636 1637 if (!cleanups.empty()) 1638 arrayInit = ExprWithCleanups::Create(ctx, arrayInit, cleanups); 1639 1640 backingArray->setInit(arrayInit); 1641 1642 // Emit the definition of the array. 1643 EmitGlobalVarDefinition(backingArray); 1644 1645 // Inspect the initializer list to validate it and determine its type. 1646 // FIXME: doing this every time is probably inefficient; caching would be nice 1647 RecordDecl *record = init->getType()->castAs<RecordType>()->getDecl(); 1648 RecordDecl::field_iterator field = record->field_begin(); 1649 if (field == record->field_end()) { 1650 ErrorUnsupported(D, "weird std::initializer_list"); 1651 return 0; 1652 } 1653 QualType elementPtr = ctx.getPointerType(elementType.withConst()); 1654 // Start pointer. 1655 if (!ctx.hasSameType(field->getType(), elementPtr)) { 1656 ErrorUnsupported(D, "weird std::initializer_list"); 1657 return 0; 1658 } 1659 ++field; 1660 if (field == record->field_end()) { 1661 ErrorUnsupported(D, "weird std::initializer_list"); 1662 return 0; 1663 } 1664 bool isStartEnd = false; 1665 if (ctx.hasSameType(field->getType(), elementPtr)) { 1666 // End pointer. 1667 isStartEnd = true; 1668 } else if(!ctx.hasSameType(field->getType(), ctx.getSizeType())) { 1669 ErrorUnsupported(D, "weird std::initializer_list"); 1670 return 0; 1671 } 1672 1673 // Now build an APValue representing the std::initializer_list. 1674 APValue initListValue(APValue::UninitStruct(), 0, 2); 1675 APValue &startField = initListValue.getStructField(0); 1676 APValue::LValuePathEntry startOffsetPathEntry; 1677 startOffsetPathEntry.ArrayIndex = 0; 1678 startField = APValue(APValue::LValueBase(backingArray), 1679 CharUnits::fromQuantity(0), 1680 llvm::makeArrayRef(startOffsetPathEntry), 1681 /*IsOnePastTheEnd=*/false, 0); 1682 1683 if (isStartEnd) { 1684 APValue &endField = initListValue.getStructField(1); 1685 APValue::LValuePathEntry endOffsetPathEntry; 1686 endOffsetPathEntry.ArrayIndex = numInits; 1687 endField = APValue(APValue::LValueBase(backingArray), 1688 ctx.getTypeSizeInChars(elementType) * numInits, 1689 llvm::makeArrayRef(endOffsetPathEntry), 1690 /*IsOnePastTheEnd=*/true, 0); 1691 } else { 1692 APValue &sizeField = initListValue.getStructField(1); 1693 sizeField = APValue(llvm::APSInt(numElements)); 1694 } 1695 1696 // Emit the constant for the initializer_list. 1697 llvm::Constant *llvmInit = 1698 EmitConstantValueForMemory(initListValue, D->getType()); 1699 assert(llvmInit && "failed to initialize as constant"); 1700 return llvmInit; 1701 } 1702 1703 unsigned CodeGenModule::GetGlobalVarAddressSpace(const VarDecl *D, 1704 unsigned AddrSpace) { 1705 if (LangOpts.CUDA && CodeGenOpts.CUDAIsDevice) { 1706 if (D->hasAttr<CUDAConstantAttr>()) 1707 AddrSpace = getContext().getTargetAddressSpace(LangAS::cuda_constant); 1708 else if (D->hasAttr<CUDASharedAttr>()) 1709 AddrSpace = getContext().getTargetAddressSpace(LangAS::cuda_shared); 1710 else 1711 AddrSpace = getContext().getTargetAddressSpace(LangAS::cuda_device); 1712 } 1713 1714 return AddrSpace; 1715 } 1716 1717 template<typename SomeDecl> 1718 void CodeGenModule::MaybeHandleStaticInExternC(const SomeDecl *D, 1719 llvm::GlobalValue *GV) { 1720 if (!getLangOpts().CPlusPlus) 1721 return; 1722 1723 // Must have 'used' attribute, or else inline assembly can't rely on 1724 // the name existing. 1725 if (!D->template hasAttr<UsedAttr>()) 1726 return; 1727 1728 // Must have internal linkage and an ordinary name. 1729 if (!D->getIdentifier() || D->getLinkage() != InternalLinkage) 1730 return; 1731 1732 // Must be in an extern "C" context. Entities declared directly within 1733 // a record are not extern "C" even if the record is in such a context. 1734 const DeclContext *DC = D->getFirstDeclaration()->getDeclContext(); 1735 if (DC->isRecord() || !DC->isExternCContext()) 1736 return; 1737 1738 // OK, this is an internal linkage entity inside an extern "C" linkage 1739 // specification. Make a note of that so we can give it the "expected" 1740 // mangled name if nothing else is using that name. 1741 std::pair<StaticExternCMap::iterator, bool> R = 1742 StaticExternCValues.insert(std::make_pair(D->getIdentifier(), GV)); 1743 1744 // If we have multiple internal linkage entities with the same name 1745 // in extern "C" regions, none of them gets that name. 1746 if (!R.second) 1747 R.first->second = 0; 1748 } 1749 1750 void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) { 1751 llvm::Constant *Init = 0; 1752 QualType ASTTy = D->getType(); 1753 CXXRecordDecl *RD = ASTTy->getBaseElementTypeUnsafe()->getAsCXXRecordDecl(); 1754 bool NeedsGlobalCtor = false; 1755 bool NeedsGlobalDtor = RD && !RD->hasTrivialDestructor(); 1756 1757 const VarDecl *InitDecl; 1758 const Expr *InitExpr = D->getAnyInitializer(InitDecl); 1759 1760 if (!InitExpr) { 1761 // This is a tentative definition; tentative definitions are 1762 // implicitly initialized with { 0 }. 1763 // 1764 // Note that tentative definitions are only emitted at the end of 1765 // a translation unit, so they should never have incomplete 1766 // type. In addition, EmitTentativeDefinition makes sure that we 1767 // never attempt to emit a tentative definition if a real one 1768 // exists. A use may still exists, however, so we still may need 1769 // to do a RAUW. 1770 assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type"); 1771 Init = EmitNullConstant(D->getType()); 1772 } else { 1773 // If this is a std::initializer_list, emit the special initializer. 1774 Init = MaybeEmitGlobalStdInitializerListInitializer(D, InitExpr); 1775 // An empty init list will perform zero-initialization, which happens 1776 // to be exactly what we want. 1777 // FIXME: It does so in a global constructor, which is *not* what we 1778 // want. 1779 1780 if (!Init) { 1781 initializedGlobalDecl = GlobalDecl(D); 1782 Init = EmitConstantInit(*InitDecl); 1783 } 1784 if (!Init) { 1785 QualType T = InitExpr->getType(); 1786 if (D->getType()->isReferenceType()) 1787 T = D->getType(); 1788 1789 if (getLangOpts().CPlusPlus) { 1790 Init = EmitNullConstant(T); 1791 NeedsGlobalCtor = true; 1792 } else { 1793 ErrorUnsupported(D, "static initializer"); 1794 Init = llvm::UndefValue::get(getTypes().ConvertType(T)); 1795 } 1796 } else { 1797 // We don't need an initializer, so remove the entry for the delayed 1798 // initializer position (just in case this entry was delayed) if we 1799 // also don't need to register a destructor. 1800 if (getLangOpts().CPlusPlus && !NeedsGlobalDtor) 1801 DelayedCXXInitPosition.erase(D); 1802 } 1803 } 1804 1805 llvm::Type* InitType = Init->getType(); 1806 llvm::Constant *Entry = GetAddrOfGlobalVar(D, InitType); 1807 1808 // Strip off a bitcast if we got one back. 1809 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 1810 assert(CE->getOpcode() == llvm::Instruction::BitCast || 1811 // all zero index gep. 1812 CE->getOpcode() == llvm::Instruction::GetElementPtr); 1813 Entry = CE->getOperand(0); 1814 } 1815 1816 // Entry is now either a Function or GlobalVariable. 1817 llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Entry); 1818 1819 // We have a definition after a declaration with the wrong type. 1820 // We must make a new GlobalVariable* and update everything that used OldGV 1821 // (a declaration or tentative definition) with the new GlobalVariable* 1822 // (which will be a definition). 1823 // 1824 // This happens if there is a prototype for a global (e.g. 1825 // "extern int x[];") and then a definition of a different type (e.g. 1826 // "int x[10];"). This also happens when an initializer has a different type 1827 // from the type of the global (this happens with unions). 1828 if (GV == 0 || 1829 GV->getType()->getElementType() != InitType || 1830 GV->getType()->getAddressSpace() != 1831 GetGlobalVarAddressSpace(D, getContext().getTargetAddressSpace(ASTTy))) { 1832 1833 // Move the old entry aside so that we'll create a new one. 1834 Entry->setName(StringRef()); 1835 1836 // Make a new global with the correct type, this is now guaranteed to work. 1837 GV = cast<llvm::GlobalVariable>(GetAddrOfGlobalVar(D, InitType)); 1838 1839 // Replace all uses of the old global with the new global 1840 llvm::Constant *NewPtrForOldDecl = 1841 llvm::ConstantExpr::getBitCast(GV, Entry->getType()); 1842 Entry->replaceAllUsesWith(NewPtrForOldDecl); 1843 1844 // Erase the old global, since it is no longer used. 1845 cast<llvm::GlobalValue>(Entry)->eraseFromParent(); 1846 } 1847 1848 MaybeHandleStaticInExternC(D, GV); 1849 1850 if (D->hasAttr<AnnotateAttr>()) 1851 AddGlobalAnnotations(D, GV); 1852 1853 GV->setInitializer(Init); 1854 1855 // If it is safe to mark the global 'constant', do so now. 1856 GV->setConstant(!NeedsGlobalCtor && !NeedsGlobalDtor && 1857 isTypeConstant(D->getType(), true)); 1858 1859 GV->setAlignment(getContext().getDeclAlign(D).getQuantity()); 1860 1861 // Set the llvm linkage type as appropriate. 1862 llvm::GlobalValue::LinkageTypes Linkage = 1863 GetLLVMLinkageVarDefinition(D, GV); 1864 GV->setLinkage(Linkage); 1865 if (Linkage == llvm::GlobalVariable::CommonLinkage) 1866 // common vars aren't constant even if declared const. 1867 GV->setConstant(false); 1868 1869 SetCommonAttributes(D, GV); 1870 1871 // Emit the initializer function if necessary. 1872 if (NeedsGlobalCtor || NeedsGlobalDtor) 1873 EmitCXXGlobalVarDeclInitFunc(D, GV, NeedsGlobalCtor); 1874 1875 // If we are compiling with ASan, add metadata indicating dynamically 1876 // initialized globals. 1877 if (SanOpts.Address && NeedsGlobalCtor) { 1878 llvm::Module &M = getModule(); 1879 1880 llvm::NamedMDNode *DynamicInitializers = 1881 M.getOrInsertNamedMetadata("llvm.asan.dynamically_initialized_globals"); 1882 llvm::Value *GlobalToAdd[] = { GV }; 1883 llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalToAdd); 1884 DynamicInitializers->addOperand(ThisGlobal); 1885 } 1886 1887 // Emit global variable debug information. 1888 if (CGDebugInfo *DI = getModuleDebugInfo()) 1889 if (getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo) 1890 DI->EmitGlobalVariable(GV, D); 1891 } 1892 1893 llvm::GlobalValue::LinkageTypes 1894 CodeGenModule::GetLLVMLinkageVarDefinition(const VarDecl *D, 1895 llvm::GlobalVariable *GV) { 1896 GVALinkage Linkage = getContext().GetGVALinkageForVariable(D); 1897 if (Linkage == GVA_Internal) 1898 return llvm::Function::InternalLinkage; 1899 else if (D->hasAttr<DLLImportAttr>()) 1900 return llvm::Function::DLLImportLinkage; 1901 else if (D->hasAttr<DLLExportAttr>()) 1902 return llvm::Function::DLLExportLinkage; 1903 else if (D->hasAttr<WeakAttr>()) { 1904 if (GV->isConstant()) 1905 return llvm::GlobalVariable::WeakODRLinkage; 1906 else 1907 return llvm::GlobalVariable::WeakAnyLinkage; 1908 } else if (Linkage == GVA_TemplateInstantiation || 1909 Linkage == GVA_ExplicitTemplateInstantiation) 1910 return llvm::GlobalVariable::WeakODRLinkage; 1911 else if (!getLangOpts().CPlusPlus && 1912 ((!CodeGenOpts.NoCommon && !D->getAttr<NoCommonAttr>()) || 1913 D->getAttr<CommonAttr>()) && 1914 !D->hasExternalStorage() && !D->getInit() && 1915 !D->getAttr<SectionAttr>() && !D->getTLSKind() && 1916 !D->getAttr<WeakImportAttr>()) { 1917 // Thread local vars aren't considered common linkage. 1918 return llvm::GlobalVariable::CommonLinkage; 1919 } else if (D->getTLSKind() == VarDecl::TLS_Dynamic && 1920 getTarget().getTriple().isMacOSX()) 1921 // On Darwin, the backing variable for a C++11 thread_local variable always 1922 // has internal linkage; all accesses should just be calls to the 1923 // Itanium-specified entry point, which has the normal linkage of the 1924 // variable. 1925 return llvm::GlobalValue::InternalLinkage; 1926 return llvm::GlobalVariable::ExternalLinkage; 1927 } 1928 1929 /// Replace the uses of a function that was declared with a non-proto type. 1930 /// We want to silently drop extra arguments from call sites 1931 static void replaceUsesOfNonProtoConstant(llvm::Constant *old, 1932 llvm::Function *newFn) { 1933 // Fast path. 1934 if (old->use_empty()) return; 1935 1936 llvm::Type *newRetTy = newFn->getReturnType(); 1937 SmallVector<llvm::Value*, 4> newArgs; 1938 1939 for (llvm::Value::use_iterator ui = old->use_begin(), ue = old->use_end(); 1940 ui != ue; ) { 1941 llvm::Value::use_iterator use = ui++; // Increment before the use is erased. 1942 llvm::User *user = *use; 1943 1944 // Recognize and replace uses of bitcasts. Most calls to 1945 // unprototyped functions will use bitcasts. 1946 if (llvm::ConstantExpr *bitcast = dyn_cast<llvm::ConstantExpr>(user)) { 1947 if (bitcast->getOpcode() == llvm::Instruction::BitCast) 1948 replaceUsesOfNonProtoConstant(bitcast, newFn); 1949 continue; 1950 } 1951 1952 // Recognize calls to the function. 1953 llvm::CallSite callSite(user); 1954 if (!callSite) continue; 1955 if (!callSite.isCallee(use)) continue; 1956 1957 // If the return types don't match exactly, then we can't 1958 // transform this call unless it's dead. 1959 if (callSite->getType() != newRetTy && !callSite->use_empty()) 1960 continue; 1961 1962 // Get the call site's attribute list. 1963 SmallVector<llvm::AttributeSet, 8> newAttrs; 1964 llvm::AttributeSet oldAttrs = callSite.getAttributes(); 1965 1966 // Collect any return attributes from the call. 1967 if (oldAttrs.hasAttributes(llvm::AttributeSet::ReturnIndex)) 1968 newAttrs.push_back( 1969 llvm::AttributeSet::get(newFn->getContext(), 1970 oldAttrs.getRetAttributes())); 1971 1972 // If the function was passed too few arguments, don't transform. 1973 unsigned newNumArgs = newFn->arg_size(); 1974 if (callSite.arg_size() < newNumArgs) continue; 1975 1976 // If extra arguments were passed, we silently drop them. 1977 // If any of the types mismatch, we don't transform. 1978 unsigned argNo = 0; 1979 bool dontTransform = false; 1980 for (llvm::Function::arg_iterator ai = newFn->arg_begin(), 1981 ae = newFn->arg_end(); ai != ae; ++ai, ++argNo) { 1982 if (callSite.getArgument(argNo)->getType() != ai->getType()) { 1983 dontTransform = true; 1984 break; 1985 } 1986 1987 // Add any parameter attributes. 1988 if (oldAttrs.hasAttributes(argNo + 1)) 1989 newAttrs. 1990 push_back(llvm:: 1991 AttributeSet::get(newFn->getContext(), 1992 oldAttrs.getParamAttributes(argNo + 1))); 1993 } 1994 if (dontTransform) 1995 continue; 1996 1997 if (oldAttrs.hasAttributes(llvm::AttributeSet::FunctionIndex)) 1998 newAttrs.push_back(llvm::AttributeSet::get(newFn->getContext(), 1999 oldAttrs.getFnAttributes())); 2000 2001 // Okay, we can transform this. Create the new call instruction and copy 2002 // over the required information. 2003 newArgs.append(callSite.arg_begin(), callSite.arg_begin() + argNo); 2004 2005 llvm::CallSite newCall; 2006 if (callSite.isCall()) { 2007 newCall = llvm::CallInst::Create(newFn, newArgs, "", 2008 callSite.getInstruction()); 2009 } else { 2010 llvm::InvokeInst *oldInvoke = 2011 cast<llvm::InvokeInst>(callSite.getInstruction()); 2012 newCall = llvm::InvokeInst::Create(newFn, 2013 oldInvoke->getNormalDest(), 2014 oldInvoke->getUnwindDest(), 2015 newArgs, "", 2016 callSite.getInstruction()); 2017 } 2018 newArgs.clear(); // for the next iteration 2019 2020 if (!newCall->getType()->isVoidTy()) 2021 newCall->takeName(callSite.getInstruction()); 2022 newCall.setAttributes( 2023 llvm::AttributeSet::get(newFn->getContext(), newAttrs)); 2024 newCall.setCallingConv(callSite.getCallingConv()); 2025 2026 // Finally, remove the old call, replacing any uses with the new one. 2027 if (!callSite->use_empty()) 2028 callSite->replaceAllUsesWith(newCall.getInstruction()); 2029 2030 // Copy debug location attached to CI. 2031 if (!callSite->getDebugLoc().isUnknown()) 2032 newCall->setDebugLoc(callSite->getDebugLoc()); 2033 callSite->eraseFromParent(); 2034 } 2035 } 2036 2037 /// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we 2038 /// implement a function with no prototype, e.g. "int foo() {}". If there are 2039 /// existing call uses of the old function in the module, this adjusts them to 2040 /// call the new function directly. 2041 /// 2042 /// This is not just a cleanup: the always_inline pass requires direct calls to 2043 /// functions to be able to inline them. If there is a bitcast in the way, it 2044 /// won't inline them. Instcombine normally deletes these calls, but it isn't 2045 /// run at -O0. 2046 static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old, 2047 llvm::Function *NewFn) { 2048 // If we're redefining a global as a function, don't transform it. 2049 if (!isa<llvm::Function>(Old)) return; 2050 2051 replaceUsesOfNonProtoConstant(Old, NewFn); 2052 } 2053 2054 void CodeGenModule::HandleCXXStaticMemberVarInstantiation(VarDecl *VD) { 2055 TemplateSpecializationKind TSK = VD->getTemplateSpecializationKind(); 2056 // If we have a definition, this might be a deferred decl. If the 2057 // instantiation is explicit, make sure we emit it at the end. 2058 if (VD->getDefinition() && TSK == TSK_ExplicitInstantiationDefinition) 2059 GetAddrOfGlobalVar(VD); 2060 2061 EmitTopLevelDecl(VD); 2062 } 2063 2064 void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD) { 2065 const FunctionDecl *D = cast<FunctionDecl>(GD.getDecl()); 2066 2067 // Compute the function info and LLVM type. 2068 const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD); 2069 llvm::FunctionType *Ty = getTypes().GetFunctionType(FI); 2070 2071 // Get or create the prototype for the function. 2072 llvm::Constant *Entry = GetAddrOfFunction(GD, Ty); 2073 2074 // Strip off a bitcast if we got one back. 2075 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 2076 assert(CE->getOpcode() == llvm::Instruction::BitCast); 2077 Entry = CE->getOperand(0); 2078 } 2079 2080 2081 if (cast<llvm::GlobalValue>(Entry)->getType()->getElementType() != Ty) { 2082 llvm::GlobalValue *OldFn = cast<llvm::GlobalValue>(Entry); 2083 2084 // If the types mismatch then we have to rewrite the definition. 2085 assert(OldFn->isDeclaration() && 2086 "Shouldn't replace non-declaration"); 2087 2088 // F is the Function* for the one with the wrong type, we must make a new 2089 // Function* and update everything that used F (a declaration) with the new 2090 // Function* (which will be a definition). 2091 // 2092 // This happens if there is a prototype for a function 2093 // (e.g. "int f()") and then a definition of a different type 2094 // (e.g. "int f(int x)"). Move the old function aside so that it 2095 // doesn't interfere with GetAddrOfFunction. 2096 OldFn->setName(StringRef()); 2097 llvm::Function *NewFn = cast<llvm::Function>(GetAddrOfFunction(GD, Ty)); 2098 2099 // This might be an implementation of a function without a 2100 // prototype, in which case, try to do special replacement of 2101 // calls which match the new prototype. The really key thing here 2102 // is that we also potentially drop arguments from the call site 2103 // so as to make a direct call, which makes the inliner happier 2104 // and suppresses a number of optimizer warnings (!) about 2105 // dropping arguments. 2106 if (!OldFn->use_empty()) { 2107 ReplaceUsesOfNonProtoTypeWithRealFunction(OldFn, NewFn); 2108 OldFn->removeDeadConstantUsers(); 2109 } 2110 2111 // Replace uses of F with the Function we will endow with a body. 2112 if (!Entry->use_empty()) { 2113 llvm::Constant *NewPtrForOldDecl = 2114 llvm::ConstantExpr::getBitCast(NewFn, Entry->getType()); 2115 Entry->replaceAllUsesWith(NewPtrForOldDecl); 2116 } 2117 2118 // Ok, delete the old function now, which is dead. 2119 OldFn->eraseFromParent(); 2120 2121 Entry = NewFn; 2122 } 2123 2124 // We need to set linkage and visibility on the function before 2125 // generating code for it because various parts of IR generation 2126 // want to propagate this information down (e.g. to local static 2127 // declarations). 2128 llvm::Function *Fn = cast<llvm::Function>(Entry); 2129 setFunctionLinkage(D, Fn); 2130 2131 // FIXME: this is redundant with part of SetFunctionDefinitionAttributes 2132 setGlobalVisibility(Fn, D); 2133 2134 MaybeHandleStaticInExternC(D, Fn); 2135 2136 CodeGenFunction(*this).GenerateCode(D, Fn, FI); 2137 2138 SetFunctionDefinitionAttributes(D, Fn); 2139 SetLLVMFunctionAttributesForDefinition(D, Fn); 2140 2141 if (const ConstructorAttr *CA = D->getAttr<ConstructorAttr>()) 2142 AddGlobalCtor(Fn, CA->getPriority()); 2143 if (const DestructorAttr *DA = D->getAttr<DestructorAttr>()) 2144 AddGlobalDtor(Fn, DA->getPriority()); 2145 if (D->hasAttr<AnnotateAttr>()) 2146 AddGlobalAnnotations(D, Fn); 2147 } 2148 2149 void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) { 2150 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 2151 const AliasAttr *AA = D->getAttr<AliasAttr>(); 2152 assert(AA && "Not an alias?"); 2153 2154 StringRef MangledName = getMangledName(GD); 2155 2156 // If there is a definition in the module, then it wins over the alias. 2157 // This is dubious, but allow it to be safe. Just ignore the alias. 2158 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 2159 if (Entry && !Entry->isDeclaration()) 2160 return; 2161 2162 llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType()); 2163 2164 // Create a reference to the named value. This ensures that it is emitted 2165 // if a deferred decl. 2166 llvm::Constant *Aliasee; 2167 if (isa<llvm::FunctionType>(DeclTy)) 2168 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GD, 2169 /*ForVTable=*/false); 2170 else 2171 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 2172 llvm::PointerType::getUnqual(DeclTy), 0); 2173 2174 // Create the new alias itself, but don't set a name yet. 2175 llvm::GlobalValue *GA = 2176 new llvm::GlobalAlias(Aliasee->getType(), 2177 llvm::Function::ExternalLinkage, 2178 "", Aliasee, &getModule()); 2179 2180 if (Entry) { 2181 assert(Entry->isDeclaration()); 2182 2183 // If there is a declaration in the module, then we had an extern followed 2184 // by the alias, as in: 2185 // extern int test6(); 2186 // ... 2187 // int test6() __attribute__((alias("test7"))); 2188 // 2189 // Remove it and replace uses of it with the alias. 2190 GA->takeName(Entry); 2191 2192 Entry->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GA, 2193 Entry->getType())); 2194 Entry->eraseFromParent(); 2195 } else { 2196 GA->setName(MangledName); 2197 } 2198 2199 // Set attributes which are particular to an alias; this is a 2200 // specialization of the attributes which may be set on a global 2201 // variable/function. 2202 if (D->hasAttr<DLLExportAttr>()) { 2203 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 2204 // The dllexport attribute is ignored for undefined symbols. 2205 if (FD->hasBody()) 2206 GA->setLinkage(llvm::Function::DLLExportLinkage); 2207 } else { 2208 GA->setLinkage(llvm::Function::DLLExportLinkage); 2209 } 2210 } else if (D->hasAttr<WeakAttr>() || 2211 D->hasAttr<WeakRefAttr>() || 2212 D->isWeakImported()) { 2213 GA->setLinkage(llvm::Function::WeakAnyLinkage); 2214 } 2215 2216 SetCommonAttributes(D, GA); 2217 } 2218 2219 llvm::Function *CodeGenModule::getIntrinsic(unsigned IID, 2220 ArrayRef<llvm::Type*> Tys) { 2221 return llvm::Intrinsic::getDeclaration(&getModule(), (llvm::Intrinsic::ID)IID, 2222 Tys); 2223 } 2224 2225 static llvm::StringMapEntry<llvm::Constant*> & 2226 GetConstantCFStringEntry(llvm::StringMap<llvm::Constant*> &Map, 2227 const StringLiteral *Literal, 2228 bool TargetIsLSB, 2229 bool &IsUTF16, 2230 unsigned &StringLength) { 2231 StringRef String = Literal->getString(); 2232 unsigned NumBytes = String.size(); 2233 2234 // Check for simple case. 2235 if (!Literal->containsNonAsciiOrNull()) { 2236 StringLength = NumBytes; 2237 return Map.GetOrCreateValue(String); 2238 } 2239 2240 // Otherwise, convert the UTF8 literals into a string of shorts. 2241 IsUTF16 = true; 2242 2243 SmallVector<UTF16, 128> ToBuf(NumBytes + 1); // +1 for ending nulls. 2244 const UTF8 *FromPtr = (const UTF8 *)String.data(); 2245 UTF16 *ToPtr = &ToBuf[0]; 2246 2247 (void)ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 2248 &ToPtr, ToPtr + NumBytes, 2249 strictConversion); 2250 2251 // ConvertUTF8toUTF16 returns the length in ToPtr. 2252 StringLength = ToPtr - &ToBuf[0]; 2253 2254 // Add an explicit null. 2255 *ToPtr = 0; 2256 return Map. 2257 GetOrCreateValue(StringRef(reinterpret_cast<const char *>(ToBuf.data()), 2258 (StringLength + 1) * 2)); 2259 } 2260 2261 static llvm::StringMapEntry<llvm::Constant*> & 2262 GetConstantStringEntry(llvm::StringMap<llvm::Constant*> &Map, 2263 const StringLiteral *Literal, 2264 unsigned &StringLength) { 2265 StringRef String = Literal->getString(); 2266 StringLength = String.size(); 2267 return Map.GetOrCreateValue(String); 2268 } 2269 2270 llvm::Constant * 2271 CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) { 2272 unsigned StringLength = 0; 2273 bool isUTF16 = false; 2274 llvm::StringMapEntry<llvm::Constant*> &Entry = 2275 GetConstantCFStringEntry(CFConstantStringMap, Literal, 2276 getDataLayout().isLittleEndian(), 2277 isUTF16, StringLength); 2278 2279 if (llvm::Constant *C = Entry.getValue()) 2280 return C; 2281 2282 llvm::Constant *Zero = llvm::Constant::getNullValue(Int32Ty); 2283 llvm::Constant *Zeros[] = { Zero, Zero }; 2284 llvm::Value *V; 2285 2286 // If we don't already have it, get __CFConstantStringClassReference. 2287 if (!CFConstantStringClassRef) { 2288 llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy); 2289 Ty = llvm::ArrayType::get(Ty, 0); 2290 llvm::Constant *GV = CreateRuntimeVariable(Ty, 2291 "__CFConstantStringClassReference"); 2292 // Decay array -> ptr 2293 V = llvm::ConstantExpr::getGetElementPtr(GV, Zeros); 2294 CFConstantStringClassRef = V; 2295 } 2296 else 2297 V = CFConstantStringClassRef; 2298 2299 QualType CFTy = getContext().getCFConstantStringType(); 2300 2301 llvm::StructType *STy = 2302 cast<llvm::StructType>(getTypes().ConvertType(CFTy)); 2303 2304 llvm::Constant *Fields[4]; 2305 2306 // Class pointer. 2307 Fields[0] = cast<llvm::ConstantExpr>(V); 2308 2309 // Flags. 2310 llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy); 2311 Fields[1] = isUTF16 ? llvm::ConstantInt::get(Ty, 0x07d0) : 2312 llvm::ConstantInt::get(Ty, 0x07C8); 2313 2314 // String pointer. 2315 llvm::Constant *C = 0; 2316 if (isUTF16) { 2317 ArrayRef<uint16_t> Arr = 2318 llvm::makeArrayRef<uint16_t>(reinterpret_cast<uint16_t*>( 2319 const_cast<char *>(Entry.getKey().data())), 2320 Entry.getKey().size() / 2); 2321 C = llvm::ConstantDataArray::get(VMContext, Arr); 2322 } else { 2323 C = llvm::ConstantDataArray::getString(VMContext, Entry.getKey()); 2324 } 2325 2326 llvm::GlobalValue::LinkageTypes Linkage; 2327 if (isUTF16) 2328 // FIXME: why do utf strings get "_" labels instead of "L" labels? 2329 Linkage = llvm::GlobalValue::InternalLinkage; 2330 else 2331 // FIXME: With OS X ld 123.2 (xcode 4) and LTO we would get a linker error 2332 // when using private linkage. It is not clear if this is a bug in ld 2333 // or a reasonable new restriction. 2334 Linkage = llvm::GlobalValue::LinkerPrivateLinkage; 2335 2336 // Note: -fwritable-strings doesn't make the backing store strings of 2337 // CFStrings writable. (See <rdar://problem/10657500>) 2338 llvm::GlobalVariable *GV = 2339 new llvm::GlobalVariable(getModule(), C->getType(), /*isConstant=*/true, 2340 Linkage, C, ".str"); 2341 GV->setUnnamedAddr(true); 2342 if (isUTF16) { 2343 CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy); 2344 GV->setAlignment(Align.getQuantity()); 2345 } else { 2346 CharUnits Align = getContext().getTypeAlignInChars(getContext().CharTy); 2347 GV->setAlignment(Align.getQuantity()); 2348 } 2349 2350 // String. 2351 Fields[2] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros); 2352 2353 if (isUTF16) 2354 // Cast the UTF16 string to the correct type. 2355 Fields[2] = llvm::ConstantExpr::getBitCast(Fields[2], Int8PtrTy); 2356 2357 // String length. 2358 Ty = getTypes().ConvertType(getContext().LongTy); 2359 Fields[3] = llvm::ConstantInt::get(Ty, StringLength); 2360 2361 // The struct. 2362 C = llvm::ConstantStruct::get(STy, Fields); 2363 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 2364 llvm::GlobalVariable::PrivateLinkage, C, 2365 "_unnamed_cfstring_"); 2366 if (const char *Sect = getTarget().getCFStringSection()) 2367 GV->setSection(Sect); 2368 Entry.setValue(GV); 2369 2370 return GV; 2371 } 2372 2373 static RecordDecl * 2374 CreateRecordDecl(const ASTContext &Ctx, RecordDecl::TagKind TK, 2375 DeclContext *DC, IdentifierInfo *Id) { 2376 SourceLocation Loc; 2377 if (Ctx.getLangOpts().CPlusPlus) 2378 return CXXRecordDecl::Create(Ctx, TK, DC, Loc, Loc, Id); 2379 else 2380 return RecordDecl::Create(Ctx, TK, DC, Loc, Loc, Id); 2381 } 2382 2383 llvm::Constant * 2384 CodeGenModule::GetAddrOfConstantString(const StringLiteral *Literal) { 2385 unsigned StringLength = 0; 2386 llvm::StringMapEntry<llvm::Constant*> &Entry = 2387 GetConstantStringEntry(CFConstantStringMap, Literal, StringLength); 2388 2389 if (llvm::Constant *C = Entry.getValue()) 2390 return C; 2391 2392 llvm::Constant *Zero = llvm::Constant::getNullValue(Int32Ty); 2393 llvm::Constant *Zeros[] = { Zero, Zero }; 2394 llvm::Value *V; 2395 // If we don't already have it, get _NSConstantStringClassReference. 2396 if (!ConstantStringClassRef) { 2397 std::string StringClass(getLangOpts().ObjCConstantStringClass); 2398 llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy); 2399 llvm::Constant *GV; 2400 if (LangOpts.ObjCRuntime.isNonFragile()) { 2401 std::string str = 2402 StringClass.empty() ? "OBJC_CLASS_$_NSConstantString" 2403 : "OBJC_CLASS_$_" + StringClass; 2404 GV = getObjCRuntime().GetClassGlobal(str); 2405 // Make sure the result is of the correct type. 2406 llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 2407 V = llvm::ConstantExpr::getBitCast(GV, PTy); 2408 ConstantStringClassRef = V; 2409 } else { 2410 std::string str = 2411 StringClass.empty() ? "_NSConstantStringClassReference" 2412 : "_" + StringClass + "ClassReference"; 2413 llvm::Type *PTy = llvm::ArrayType::get(Ty, 0); 2414 GV = CreateRuntimeVariable(PTy, str); 2415 // Decay array -> ptr 2416 V = llvm::ConstantExpr::getGetElementPtr(GV, Zeros); 2417 ConstantStringClassRef = V; 2418 } 2419 } 2420 else 2421 V = ConstantStringClassRef; 2422 2423 if (!NSConstantStringType) { 2424 // Construct the type for a constant NSString. 2425 RecordDecl *D = CreateRecordDecl(Context, TTK_Struct, 2426 Context.getTranslationUnitDecl(), 2427 &Context.Idents.get("__builtin_NSString")); 2428 D->startDefinition(); 2429 2430 QualType FieldTypes[3]; 2431 2432 // const int *isa; 2433 FieldTypes[0] = Context.getPointerType(Context.IntTy.withConst()); 2434 // const char *str; 2435 FieldTypes[1] = Context.getPointerType(Context.CharTy.withConst()); 2436 // unsigned int length; 2437 FieldTypes[2] = Context.UnsignedIntTy; 2438 2439 // Create fields 2440 for (unsigned i = 0; i < 3; ++i) { 2441 FieldDecl *Field = FieldDecl::Create(Context, D, 2442 SourceLocation(), 2443 SourceLocation(), 0, 2444 FieldTypes[i], /*TInfo=*/0, 2445 /*BitWidth=*/0, 2446 /*Mutable=*/false, 2447 ICIS_NoInit); 2448 Field->setAccess(AS_public); 2449 D->addDecl(Field); 2450 } 2451 2452 D->completeDefinition(); 2453 QualType NSTy = Context.getTagDeclType(D); 2454 NSConstantStringType = cast<llvm::StructType>(getTypes().ConvertType(NSTy)); 2455 } 2456 2457 llvm::Constant *Fields[3]; 2458 2459 // Class pointer. 2460 Fields[0] = cast<llvm::ConstantExpr>(V); 2461 2462 // String pointer. 2463 llvm::Constant *C = 2464 llvm::ConstantDataArray::getString(VMContext, Entry.getKey()); 2465 2466 llvm::GlobalValue::LinkageTypes Linkage; 2467 bool isConstant; 2468 Linkage = llvm::GlobalValue::PrivateLinkage; 2469 isConstant = !LangOpts.WritableStrings; 2470 2471 llvm::GlobalVariable *GV = 2472 new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C, 2473 ".str"); 2474 GV->setUnnamedAddr(true); 2475 CharUnits Align = getContext().getTypeAlignInChars(getContext().CharTy); 2476 GV->setAlignment(Align.getQuantity()); 2477 Fields[1] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros); 2478 2479 // String length. 2480 llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy); 2481 Fields[2] = llvm::ConstantInt::get(Ty, StringLength); 2482 2483 // The struct. 2484 C = llvm::ConstantStruct::get(NSConstantStringType, Fields); 2485 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 2486 llvm::GlobalVariable::PrivateLinkage, C, 2487 "_unnamed_nsstring_"); 2488 // FIXME. Fix section. 2489 if (const char *Sect = 2490 LangOpts.ObjCRuntime.isNonFragile() 2491 ? getTarget().getNSStringNonFragileABISection() 2492 : getTarget().getNSStringSection()) 2493 GV->setSection(Sect); 2494 Entry.setValue(GV); 2495 2496 return GV; 2497 } 2498 2499 QualType CodeGenModule::getObjCFastEnumerationStateType() { 2500 if (ObjCFastEnumerationStateType.isNull()) { 2501 RecordDecl *D = CreateRecordDecl(Context, TTK_Struct, 2502 Context.getTranslationUnitDecl(), 2503 &Context.Idents.get("__objcFastEnumerationState")); 2504 D->startDefinition(); 2505 2506 QualType FieldTypes[] = { 2507 Context.UnsignedLongTy, 2508 Context.getPointerType(Context.getObjCIdType()), 2509 Context.getPointerType(Context.UnsignedLongTy), 2510 Context.getConstantArrayType(Context.UnsignedLongTy, 2511 llvm::APInt(32, 5), ArrayType::Normal, 0) 2512 }; 2513 2514 for (size_t i = 0; i < 4; ++i) { 2515 FieldDecl *Field = FieldDecl::Create(Context, 2516 D, 2517 SourceLocation(), 2518 SourceLocation(), 0, 2519 FieldTypes[i], /*TInfo=*/0, 2520 /*BitWidth=*/0, 2521 /*Mutable=*/false, 2522 ICIS_NoInit); 2523 Field->setAccess(AS_public); 2524 D->addDecl(Field); 2525 } 2526 2527 D->completeDefinition(); 2528 ObjCFastEnumerationStateType = Context.getTagDeclType(D); 2529 } 2530 2531 return ObjCFastEnumerationStateType; 2532 } 2533 2534 llvm::Constant * 2535 CodeGenModule::GetConstantArrayFromStringLiteral(const StringLiteral *E) { 2536 assert(!E->getType()->isPointerType() && "Strings are always arrays"); 2537 2538 // Don't emit it as the address of the string, emit the string data itself 2539 // as an inline array. 2540 if (E->getCharByteWidth() == 1) { 2541 SmallString<64> Str(E->getString()); 2542 2543 // Resize the string to the right size, which is indicated by its type. 2544 const ConstantArrayType *CAT = Context.getAsConstantArrayType(E->getType()); 2545 Str.resize(CAT->getSize().getZExtValue()); 2546 return llvm::ConstantDataArray::getString(VMContext, Str, false); 2547 } 2548 2549 llvm::ArrayType *AType = 2550 cast<llvm::ArrayType>(getTypes().ConvertType(E->getType())); 2551 llvm::Type *ElemTy = AType->getElementType(); 2552 unsigned NumElements = AType->getNumElements(); 2553 2554 // Wide strings have either 2-byte or 4-byte elements. 2555 if (ElemTy->getPrimitiveSizeInBits() == 16) { 2556 SmallVector<uint16_t, 32> Elements; 2557 Elements.reserve(NumElements); 2558 2559 for(unsigned i = 0, e = E->getLength(); i != e; ++i) 2560 Elements.push_back(E->getCodeUnit(i)); 2561 Elements.resize(NumElements); 2562 return llvm::ConstantDataArray::get(VMContext, Elements); 2563 } 2564 2565 assert(ElemTy->getPrimitiveSizeInBits() == 32); 2566 SmallVector<uint32_t, 32> Elements; 2567 Elements.reserve(NumElements); 2568 2569 for(unsigned i = 0, e = E->getLength(); i != e; ++i) 2570 Elements.push_back(E->getCodeUnit(i)); 2571 Elements.resize(NumElements); 2572 return llvm::ConstantDataArray::get(VMContext, Elements); 2573 } 2574 2575 /// GetAddrOfConstantStringFromLiteral - Return a pointer to a 2576 /// constant array for the given string literal. 2577 llvm::Constant * 2578 CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) { 2579 CharUnits Align = getContext().getTypeAlignInChars(S->getType()); 2580 if (S->isAscii() || S->isUTF8()) { 2581 SmallString<64> Str(S->getString()); 2582 2583 // Resize the string to the right size, which is indicated by its type. 2584 const ConstantArrayType *CAT = Context.getAsConstantArrayType(S->getType()); 2585 Str.resize(CAT->getSize().getZExtValue()); 2586 return GetAddrOfConstantString(Str, /*GlobalName*/ 0, Align.getQuantity()); 2587 } 2588 2589 // FIXME: the following does not memoize wide strings. 2590 llvm::Constant *C = GetConstantArrayFromStringLiteral(S); 2591 llvm::GlobalVariable *GV = 2592 new llvm::GlobalVariable(getModule(),C->getType(), 2593 !LangOpts.WritableStrings, 2594 llvm::GlobalValue::PrivateLinkage, 2595 C,".str"); 2596 2597 GV->setAlignment(Align.getQuantity()); 2598 GV->setUnnamedAddr(true); 2599 return GV; 2600 } 2601 2602 /// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant 2603 /// array for the given ObjCEncodeExpr node. 2604 llvm::Constant * 2605 CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) { 2606 std::string Str; 2607 getContext().getObjCEncodingForType(E->getEncodedType(), Str); 2608 2609 return GetAddrOfConstantCString(Str); 2610 } 2611 2612 2613 /// GenerateWritableString -- Creates storage for a string literal. 2614 static llvm::GlobalVariable *GenerateStringLiteral(StringRef str, 2615 bool constant, 2616 CodeGenModule &CGM, 2617 const char *GlobalName, 2618 unsigned Alignment) { 2619 // Create Constant for this string literal. Don't add a '\0'. 2620 llvm::Constant *C = 2621 llvm::ConstantDataArray::getString(CGM.getLLVMContext(), str, false); 2622 2623 // Create a global variable for this string 2624 llvm::GlobalVariable *GV = 2625 new llvm::GlobalVariable(CGM.getModule(), C->getType(), constant, 2626 llvm::GlobalValue::PrivateLinkage, 2627 C, GlobalName); 2628 GV->setAlignment(Alignment); 2629 GV->setUnnamedAddr(true); 2630 return GV; 2631 } 2632 2633 /// GetAddrOfConstantString - Returns a pointer to a character array 2634 /// containing the literal. This contents are exactly that of the 2635 /// given string, i.e. it will not be null terminated automatically; 2636 /// see GetAddrOfConstantCString. Note that whether the result is 2637 /// actually a pointer to an LLVM constant depends on 2638 /// Feature.WriteableStrings. 2639 /// 2640 /// The result has pointer to array type. 2641 llvm::Constant *CodeGenModule::GetAddrOfConstantString(StringRef Str, 2642 const char *GlobalName, 2643 unsigned Alignment) { 2644 // Get the default prefix if a name wasn't specified. 2645 if (!GlobalName) 2646 GlobalName = ".str"; 2647 2648 // Don't share any string literals if strings aren't constant. 2649 if (LangOpts.WritableStrings) 2650 return GenerateStringLiteral(Str, false, *this, GlobalName, Alignment); 2651 2652 llvm::StringMapEntry<llvm::GlobalVariable *> &Entry = 2653 ConstantStringMap.GetOrCreateValue(Str); 2654 2655 if (llvm::GlobalVariable *GV = Entry.getValue()) { 2656 if (Alignment > GV->getAlignment()) { 2657 GV->setAlignment(Alignment); 2658 } 2659 return GV; 2660 } 2661 2662 // Create a global variable for this. 2663 llvm::GlobalVariable *GV = GenerateStringLiteral(Str, true, *this, GlobalName, 2664 Alignment); 2665 Entry.setValue(GV); 2666 return GV; 2667 } 2668 2669 /// GetAddrOfConstantCString - Returns a pointer to a character 2670 /// array containing the literal and a terminating '\0' 2671 /// character. The result has pointer to array type. 2672 llvm::Constant *CodeGenModule::GetAddrOfConstantCString(const std::string &Str, 2673 const char *GlobalName, 2674 unsigned Alignment) { 2675 StringRef StrWithNull(Str.c_str(), Str.size() + 1); 2676 return GetAddrOfConstantString(StrWithNull, GlobalName, Alignment); 2677 } 2678 2679 /// EmitObjCPropertyImplementations - Emit information for synthesized 2680 /// properties for an implementation. 2681 void CodeGenModule::EmitObjCPropertyImplementations(const 2682 ObjCImplementationDecl *D) { 2683 for (ObjCImplementationDecl::propimpl_iterator 2684 i = D->propimpl_begin(), e = D->propimpl_end(); i != e; ++i) { 2685 ObjCPropertyImplDecl *PID = *i; 2686 2687 // Dynamic is just for type-checking. 2688 if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize) { 2689 ObjCPropertyDecl *PD = PID->getPropertyDecl(); 2690 2691 // Determine which methods need to be implemented, some may have 2692 // been overridden. Note that ::isPropertyAccessor is not the method 2693 // we want, that just indicates if the decl came from a 2694 // property. What we want to know is if the method is defined in 2695 // this implementation. 2696 if (!D->getInstanceMethod(PD->getGetterName())) 2697 CodeGenFunction(*this).GenerateObjCGetter( 2698 const_cast<ObjCImplementationDecl *>(D), PID); 2699 if (!PD->isReadOnly() && 2700 !D->getInstanceMethod(PD->getSetterName())) 2701 CodeGenFunction(*this).GenerateObjCSetter( 2702 const_cast<ObjCImplementationDecl *>(D), PID); 2703 } 2704 } 2705 } 2706 2707 static bool needsDestructMethod(ObjCImplementationDecl *impl) { 2708 const ObjCInterfaceDecl *iface = impl->getClassInterface(); 2709 for (const ObjCIvarDecl *ivar = iface->all_declared_ivar_begin(); 2710 ivar; ivar = ivar->getNextIvar()) 2711 if (ivar->getType().isDestructedType()) 2712 return true; 2713 2714 return false; 2715 } 2716 2717 /// EmitObjCIvarInitializations - Emit information for ivar initialization 2718 /// for an implementation. 2719 void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) { 2720 // We might need a .cxx_destruct even if we don't have any ivar initializers. 2721 if (needsDestructMethod(D)) { 2722 IdentifierInfo *II = &getContext().Idents.get(".cxx_destruct"); 2723 Selector cxxSelector = getContext().Selectors.getSelector(0, &II); 2724 ObjCMethodDecl *DTORMethod = 2725 ObjCMethodDecl::Create(getContext(), D->getLocation(), D->getLocation(), 2726 cxxSelector, getContext().VoidTy, 0, D, 2727 /*isInstance=*/true, /*isVariadic=*/false, 2728 /*isPropertyAccessor=*/true, /*isImplicitlyDeclared=*/true, 2729 /*isDefined=*/false, ObjCMethodDecl::Required); 2730 D->addInstanceMethod(DTORMethod); 2731 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, DTORMethod, false); 2732 D->setHasDestructors(true); 2733 } 2734 2735 // If the implementation doesn't have any ivar initializers, we don't need 2736 // a .cxx_construct. 2737 if (D->getNumIvarInitializers() == 0) 2738 return; 2739 2740 IdentifierInfo *II = &getContext().Idents.get(".cxx_construct"); 2741 Selector cxxSelector = getContext().Selectors.getSelector(0, &II); 2742 // The constructor returns 'self'. 2743 ObjCMethodDecl *CTORMethod = ObjCMethodDecl::Create(getContext(), 2744 D->getLocation(), 2745 D->getLocation(), 2746 cxxSelector, 2747 getContext().getObjCIdType(), 0, 2748 D, /*isInstance=*/true, 2749 /*isVariadic=*/false, 2750 /*isPropertyAccessor=*/true, 2751 /*isImplicitlyDeclared=*/true, 2752 /*isDefined=*/false, 2753 ObjCMethodDecl::Required); 2754 D->addInstanceMethod(CTORMethod); 2755 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, CTORMethod, true); 2756 D->setHasNonZeroConstructors(true); 2757 } 2758 2759 /// EmitNamespace - Emit all declarations in a namespace. 2760 void CodeGenModule::EmitNamespace(const NamespaceDecl *ND) { 2761 for (RecordDecl::decl_iterator I = ND->decls_begin(), E = ND->decls_end(); 2762 I != E; ++I) 2763 EmitTopLevelDecl(*I); 2764 } 2765 2766 // EmitLinkageSpec - Emit all declarations in a linkage spec. 2767 void CodeGenModule::EmitLinkageSpec(const LinkageSpecDecl *LSD) { 2768 if (LSD->getLanguage() != LinkageSpecDecl::lang_c && 2769 LSD->getLanguage() != LinkageSpecDecl::lang_cxx) { 2770 ErrorUnsupported(LSD, "linkage spec"); 2771 return; 2772 } 2773 2774 for (RecordDecl::decl_iterator I = LSD->decls_begin(), E = LSD->decls_end(); 2775 I != E; ++I) { 2776 // Meta-data for ObjC class includes references to implemented methods. 2777 // Generate class's method definitions first. 2778 if (ObjCImplDecl *OID = dyn_cast<ObjCImplDecl>(*I)) { 2779 for (ObjCContainerDecl::method_iterator M = OID->meth_begin(), 2780 MEnd = OID->meth_end(); 2781 M != MEnd; ++M) 2782 EmitTopLevelDecl(*M); 2783 } 2784 EmitTopLevelDecl(*I); 2785 } 2786 } 2787 2788 /// EmitTopLevelDecl - Emit code for a single top level declaration. 2789 void CodeGenModule::EmitTopLevelDecl(Decl *D) { 2790 // If an error has occurred, stop code generation, but continue 2791 // parsing and semantic analysis (to ensure all warnings and errors 2792 // are emitted). 2793 if (Diags.hasErrorOccurred()) 2794 return; 2795 2796 // Ignore dependent declarations. 2797 if (D->getDeclContext() && D->getDeclContext()->isDependentContext()) 2798 return; 2799 2800 switch (D->getKind()) { 2801 case Decl::CXXConversion: 2802 case Decl::CXXMethod: 2803 case Decl::Function: 2804 // Skip function templates 2805 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate() || 2806 cast<FunctionDecl>(D)->isLateTemplateParsed()) 2807 return; 2808 2809 EmitGlobal(cast<FunctionDecl>(D)); 2810 break; 2811 2812 case Decl::Var: 2813 EmitGlobal(cast<VarDecl>(D)); 2814 break; 2815 2816 // Indirect fields from global anonymous structs and unions can be 2817 // ignored; only the actual variable requires IR gen support. 2818 case Decl::IndirectField: 2819 break; 2820 2821 // C++ Decls 2822 case Decl::Namespace: 2823 EmitNamespace(cast<NamespaceDecl>(D)); 2824 break; 2825 // No code generation needed. 2826 case Decl::UsingShadow: 2827 case Decl::Using: 2828 case Decl::ClassTemplate: 2829 case Decl::FunctionTemplate: 2830 case Decl::TypeAliasTemplate: 2831 case Decl::NamespaceAlias: 2832 case Decl::Block: 2833 case Decl::Empty: 2834 break; 2835 case Decl::UsingDirective: // using namespace X; [C++] 2836 if (CGDebugInfo *DI = getModuleDebugInfo()) 2837 DI->EmitUsingDirective(cast<UsingDirectiveDecl>(*D)); 2838 return; 2839 case Decl::CXXConstructor: 2840 // Skip function templates 2841 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate() || 2842 cast<FunctionDecl>(D)->isLateTemplateParsed()) 2843 return; 2844 2845 EmitCXXConstructors(cast<CXXConstructorDecl>(D)); 2846 break; 2847 case Decl::CXXDestructor: 2848 if (cast<FunctionDecl>(D)->isLateTemplateParsed()) 2849 return; 2850 EmitCXXDestructors(cast<CXXDestructorDecl>(D)); 2851 break; 2852 2853 case Decl::StaticAssert: 2854 // Nothing to do. 2855 break; 2856 2857 // Objective-C Decls 2858 2859 // Forward declarations, no (immediate) code generation. 2860 case Decl::ObjCInterface: 2861 case Decl::ObjCCategory: 2862 break; 2863 2864 case Decl::ObjCProtocol: { 2865 ObjCProtocolDecl *Proto = cast<ObjCProtocolDecl>(D); 2866 if (Proto->isThisDeclarationADefinition()) 2867 ObjCRuntime->GenerateProtocol(Proto); 2868 break; 2869 } 2870 2871 case Decl::ObjCCategoryImpl: 2872 // Categories have properties but don't support synthesize so we 2873 // can ignore them here. 2874 ObjCRuntime->GenerateCategory(cast<ObjCCategoryImplDecl>(D)); 2875 break; 2876 2877 case Decl::ObjCImplementation: { 2878 ObjCImplementationDecl *OMD = cast<ObjCImplementationDecl>(D); 2879 EmitObjCPropertyImplementations(OMD); 2880 EmitObjCIvarInitializations(OMD); 2881 ObjCRuntime->GenerateClass(OMD); 2882 // Emit global variable debug information. 2883 if (CGDebugInfo *DI = getModuleDebugInfo()) 2884 if (getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo) 2885 DI->getOrCreateInterfaceType(getContext().getObjCInterfaceType( 2886 OMD->getClassInterface()), OMD->getLocation()); 2887 break; 2888 } 2889 case Decl::ObjCMethod: { 2890 ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(D); 2891 // If this is not a prototype, emit the body. 2892 if (OMD->getBody()) 2893 CodeGenFunction(*this).GenerateObjCMethod(OMD); 2894 break; 2895 } 2896 case Decl::ObjCCompatibleAlias: 2897 ObjCRuntime->RegisterAlias(cast<ObjCCompatibleAliasDecl>(D)); 2898 break; 2899 2900 case Decl::LinkageSpec: 2901 EmitLinkageSpec(cast<LinkageSpecDecl>(D)); 2902 break; 2903 2904 case Decl::FileScopeAsm: { 2905 FileScopeAsmDecl *AD = cast<FileScopeAsmDecl>(D); 2906 StringRef AsmString = AD->getAsmString()->getString(); 2907 2908 const std::string &S = getModule().getModuleInlineAsm(); 2909 if (S.empty()) 2910 getModule().setModuleInlineAsm(AsmString); 2911 else if (S.end()[-1] == '\n') 2912 getModule().setModuleInlineAsm(S + AsmString.str()); 2913 else 2914 getModule().setModuleInlineAsm(S + '\n' + AsmString.str()); 2915 break; 2916 } 2917 2918 case Decl::Import: { 2919 ImportDecl *Import = cast<ImportDecl>(D); 2920 2921 // Ignore import declarations that come from imported modules. 2922 if (clang::Module *Owner = Import->getOwningModule()) { 2923 if (getLangOpts().CurrentModule.empty() || 2924 Owner->getTopLevelModule()->Name == getLangOpts().CurrentModule) 2925 break; 2926 } 2927 2928 ImportedModules.insert(Import->getImportedModule()); 2929 break; 2930 } 2931 2932 default: 2933 // Make sure we handled everything we should, every other kind is a 2934 // non-top-level decl. FIXME: Would be nice to have an isTopLevelDeclKind 2935 // function. Need to recode Decl::Kind to do that easily. 2936 assert(isa<TypeDecl>(D) && "Unsupported decl kind"); 2937 } 2938 } 2939 2940 /// Turns the given pointer into a constant. 2941 static llvm::Constant *GetPointerConstant(llvm::LLVMContext &Context, 2942 const void *Ptr) { 2943 uintptr_t PtrInt = reinterpret_cast<uintptr_t>(Ptr); 2944 llvm::Type *i64 = llvm::Type::getInt64Ty(Context); 2945 return llvm::ConstantInt::get(i64, PtrInt); 2946 } 2947 2948 static void EmitGlobalDeclMetadata(CodeGenModule &CGM, 2949 llvm::NamedMDNode *&GlobalMetadata, 2950 GlobalDecl D, 2951 llvm::GlobalValue *Addr) { 2952 if (!GlobalMetadata) 2953 GlobalMetadata = 2954 CGM.getModule().getOrInsertNamedMetadata("clang.global.decl.ptrs"); 2955 2956 // TODO: should we report variant information for ctors/dtors? 2957 llvm::Value *Ops[] = { 2958 Addr, 2959 GetPointerConstant(CGM.getLLVMContext(), D.getDecl()) 2960 }; 2961 GlobalMetadata->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops)); 2962 } 2963 2964 /// For each function which is declared within an extern "C" region and marked 2965 /// as 'used', but has internal linkage, create an alias from the unmangled 2966 /// name to the mangled name if possible. People expect to be able to refer 2967 /// to such functions with an unmangled name from inline assembly within the 2968 /// same translation unit. 2969 void CodeGenModule::EmitStaticExternCAliases() { 2970 for (StaticExternCMap::iterator I = StaticExternCValues.begin(), 2971 E = StaticExternCValues.end(); 2972 I != E; ++I) { 2973 IdentifierInfo *Name = I->first; 2974 llvm::GlobalValue *Val = I->second; 2975 if (Val && !getModule().getNamedValue(Name->getName())) 2976 AddUsedGlobal(new llvm::GlobalAlias(Val->getType(), Val->getLinkage(), 2977 Name->getName(), Val, &getModule())); 2978 } 2979 } 2980 2981 /// Emits metadata nodes associating all the global values in the 2982 /// current module with the Decls they came from. This is useful for 2983 /// projects using IR gen as a subroutine. 2984 /// 2985 /// Since there's currently no way to associate an MDNode directly 2986 /// with an llvm::GlobalValue, we create a global named metadata 2987 /// with the name 'clang.global.decl.ptrs'. 2988 void CodeGenModule::EmitDeclMetadata() { 2989 llvm::NamedMDNode *GlobalMetadata = 0; 2990 2991 // StaticLocalDeclMap 2992 for (llvm::DenseMap<GlobalDecl,StringRef>::iterator 2993 I = MangledDeclNames.begin(), E = MangledDeclNames.end(); 2994 I != E; ++I) { 2995 llvm::GlobalValue *Addr = getModule().getNamedValue(I->second); 2996 EmitGlobalDeclMetadata(*this, GlobalMetadata, I->first, Addr); 2997 } 2998 } 2999 3000 /// Emits metadata nodes for all the local variables in the current 3001 /// function. 3002 void CodeGenFunction::EmitDeclMetadata() { 3003 if (LocalDeclMap.empty()) return; 3004 3005 llvm::LLVMContext &Context = getLLVMContext(); 3006 3007 // Find the unique metadata ID for this name. 3008 unsigned DeclPtrKind = Context.getMDKindID("clang.decl.ptr"); 3009 3010 llvm::NamedMDNode *GlobalMetadata = 0; 3011 3012 for (llvm::DenseMap<const Decl*, llvm::Value*>::iterator 3013 I = LocalDeclMap.begin(), E = LocalDeclMap.end(); I != E; ++I) { 3014 const Decl *D = I->first; 3015 llvm::Value *Addr = I->second; 3016 3017 if (llvm::AllocaInst *Alloca = dyn_cast<llvm::AllocaInst>(Addr)) { 3018 llvm::Value *DAddr = GetPointerConstant(getLLVMContext(), D); 3019 Alloca->setMetadata(DeclPtrKind, llvm::MDNode::get(Context, DAddr)); 3020 } else if (llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(Addr)) { 3021 GlobalDecl GD = GlobalDecl(cast<VarDecl>(D)); 3022 EmitGlobalDeclMetadata(CGM, GlobalMetadata, GD, GV); 3023 } 3024 } 3025 } 3026 3027 void CodeGenModule::EmitCoverageFile() { 3028 if (!getCodeGenOpts().CoverageFile.empty()) { 3029 if (llvm::NamedMDNode *CUNode = TheModule.getNamedMetadata("llvm.dbg.cu")) { 3030 llvm::NamedMDNode *GCov = TheModule.getOrInsertNamedMetadata("llvm.gcov"); 3031 llvm::LLVMContext &Ctx = TheModule.getContext(); 3032 llvm::MDString *CoverageFile = 3033 llvm::MDString::get(Ctx, getCodeGenOpts().CoverageFile); 3034 for (int i = 0, e = CUNode->getNumOperands(); i != e; ++i) { 3035 llvm::MDNode *CU = CUNode->getOperand(i); 3036 llvm::Value *node[] = { CoverageFile, CU }; 3037 llvm::MDNode *N = llvm::MDNode::get(Ctx, node); 3038 GCov->addOperand(N); 3039 } 3040 } 3041 } 3042 } 3043 3044 llvm::Constant *CodeGenModule::EmitUuidofInitializer(StringRef Uuid, 3045 QualType GuidType) { 3046 // Sema has checked that all uuid strings are of the form 3047 // "12345678-1234-1234-1234-1234567890ab". 3048 assert(Uuid.size() == 36); 3049 const char *Uuidstr = Uuid.data(); 3050 for (int i = 0; i < 36; ++i) { 3051 if (i == 8 || i == 13 || i == 18 || i == 23) assert(Uuidstr[i] == '-'); 3052 else assert(isHexDigit(Uuidstr[i])); 3053 } 3054 3055 llvm::APInt Field0(32, StringRef(Uuidstr , 8), 16); 3056 llvm::APInt Field1(16, StringRef(Uuidstr + 9, 4), 16); 3057 llvm::APInt Field2(16, StringRef(Uuidstr + 14, 4), 16); 3058 static const int Field3ValueOffsets[] = { 19, 21, 24, 26, 28, 30, 32, 34 }; 3059 3060 APValue InitStruct(APValue::UninitStruct(), /*NumBases=*/0, /*NumFields=*/4); 3061 InitStruct.getStructField(0) = APValue(llvm::APSInt(Field0)); 3062 InitStruct.getStructField(1) = APValue(llvm::APSInt(Field1)); 3063 InitStruct.getStructField(2) = APValue(llvm::APSInt(Field2)); 3064 APValue& Arr = InitStruct.getStructField(3); 3065 Arr = APValue(APValue::UninitArray(), 8, 8); 3066 for (int t = 0; t < 8; ++t) 3067 Arr.getArrayInitializedElt(t) = APValue(llvm::APSInt( 3068 llvm::APInt(8, StringRef(Uuidstr + Field3ValueOffsets[t], 2), 16))); 3069 3070 return EmitConstantValue(InitStruct, GuidType); 3071 } 3072