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 "CGDebugInfo.h" 16 #include "CodeGenFunction.h" 17 #include "CodeGenTBAA.h" 18 #include "CGCall.h" 19 #include "CGCXXABI.h" 20 #include "CGObjCRuntime.h" 21 #include "TargetInfo.h" 22 #include "clang/Frontend/CodeGenOptions.h" 23 #include "clang/AST/ASTContext.h" 24 #include "clang/AST/CharUnits.h" 25 #include "clang/AST/DeclObjC.h" 26 #include "clang/AST/DeclCXX.h" 27 #include "clang/AST/DeclTemplate.h" 28 #include "clang/AST/Mangle.h" 29 #include "clang/AST/RecordLayout.h" 30 #include "clang/Basic/Builtins.h" 31 #include "clang/Basic/Diagnostic.h" 32 #include "clang/Basic/SourceManager.h" 33 #include "clang/Basic/TargetInfo.h" 34 #include "clang/Basic/ConvertUTF.h" 35 #include "llvm/CallingConv.h" 36 #include "llvm/Module.h" 37 #include "llvm/Intrinsics.h" 38 #include "llvm/LLVMContext.h" 39 #include "llvm/ADT/Triple.h" 40 #include "llvm/Target/TargetData.h" 41 #include "llvm/Support/CallSite.h" 42 #include "llvm/Support/ErrorHandling.h" 43 using namespace clang; 44 using namespace CodeGen; 45 46 static CGCXXABI &createCXXABI(CodeGenModule &CGM) { 47 switch (CGM.getContext().Target.getCXXABI()) { 48 case CXXABI_ARM: return *CreateARMCXXABI(CGM); 49 case CXXABI_Itanium: return *CreateItaniumCXXABI(CGM); 50 case CXXABI_Microsoft: return *CreateMicrosoftCXXABI(CGM); 51 } 52 53 llvm_unreachable("invalid C++ ABI kind"); 54 return *CreateItaniumCXXABI(CGM); 55 } 56 57 58 CodeGenModule::CodeGenModule(ASTContext &C, const CodeGenOptions &CGO, 59 llvm::Module &M, const llvm::TargetData &TD, 60 Diagnostic &diags) 61 : BlockModule(C, M, TD, Types, *this), Context(C), 62 Features(C.getLangOptions()), CodeGenOpts(CGO), TheModule(M), 63 TheTargetData(TD), TheTargetCodeGenInfo(0), Diags(diags), 64 ABI(createCXXABI(*this)), 65 Types(C, M, TD, getTargetCodeGenInfo().getABIInfo(), ABI), 66 TBAA(0), 67 VTables(*this), Runtime(0), 68 CFConstantStringClassRef(0), ConstantStringClassRef(0), 69 VMContext(M.getContext()), 70 NSConcreteGlobalBlockDecl(0), NSConcreteStackBlockDecl(0), 71 NSConcreteGlobalBlock(0), NSConcreteStackBlock(0), 72 BlockObjectAssignDecl(0), BlockObjectDisposeDecl(0), 73 BlockObjectAssign(0), BlockObjectDispose(0){ 74 75 if (!Features.ObjC1) 76 Runtime = 0; 77 else if (!Features.NeXTRuntime) 78 Runtime = CreateGNUObjCRuntime(*this); 79 else if (Features.ObjCNonFragileABI) 80 Runtime = CreateMacNonFragileABIObjCRuntime(*this); 81 else 82 Runtime = CreateMacObjCRuntime(*this); 83 84 // Enable TBAA unless it's suppressed. 85 if (!CodeGenOpts.RelaxedAliasing && CodeGenOpts.OptimizationLevel > 0) 86 TBAA = new CodeGenTBAA(Context, VMContext, getLangOptions(), 87 ABI.getMangleContext()); 88 89 // If debug info generation is enabled, create the CGDebugInfo object. 90 DebugInfo = CodeGenOpts.DebugInfo ? new CGDebugInfo(*this) : 0; 91 } 92 93 CodeGenModule::~CodeGenModule() { 94 delete Runtime; 95 delete &ABI; 96 delete TBAA; 97 delete DebugInfo; 98 } 99 100 void CodeGenModule::createObjCRuntime() { 101 if (!Features.NeXTRuntime) 102 Runtime = CreateGNUObjCRuntime(*this); 103 else if (Features.ObjCNonFragileABI) 104 Runtime = CreateMacNonFragileABIObjCRuntime(*this); 105 else 106 Runtime = CreateMacObjCRuntime(*this); 107 } 108 109 void CodeGenModule::Release() { 110 EmitDeferred(); 111 EmitCXXGlobalInitFunc(); 112 EmitCXXGlobalDtorFunc(); 113 if (Runtime) 114 if (llvm::Function *ObjCInitFunction = Runtime->ModuleInitFunction()) 115 AddGlobalCtor(ObjCInitFunction); 116 EmitCtorList(GlobalCtors, "llvm.global_ctors"); 117 EmitCtorList(GlobalDtors, "llvm.global_dtors"); 118 EmitAnnotations(); 119 EmitLLVMUsed(); 120 121 SimplifyPersonality(); 122 123 if (getCodeGenOpts().EmitDeclMetadata) 124 EmitDeclMetadata(); 125 } 126 127 llvm::MDNode *CodeGenModule::getTBAAInfo(QualType QTy) { 128 if (!TBAA) 129 return 0; 130 return TBAA->getTBAAInfo(QTy); 131 } 132 133 void CodeGenModule::DecorateInstruction(llvm::Instruction *Inst, 134 llvm::MDNode *TBAAInfo) { 135 Inst->setMetadata(llvm::LLVMContext::MD_tbaa, TBAAInfo); 136 } 137 138 bool CodeGenModule::isTargetDarwin() const { 139 return getContext().Target.getTriple().getOS() == llvm::Triple::Darwin; 140 } 141 142 /// ErrorUnsupported - Print out an error that codegen doesn't support the 143 /// specified stmt yet. 144 void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type, 145 bool OmitOnError) { 146 if (OmitOnError && getDiags().hasErrorOccurred()) 147 return; 148 unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error, 149 "cannot compile this %0 yet"); 150 std::string Msg = Type; 151 getDiags().Report(Context.getFullLoc(S->getLocStart()), DiagID) 152 << Msg << S->getSourceRange(); 153 } 154 155 /// ErrorUnsupported - Print out an error that codegen doesn't support the 156 /// specified decl yet. 157 void CodeGenModule::ErrorUnsupported(const Decl *D, const char *Type, 158 bool OmitOnError) { 159 if (OmitOnError && getDiags().hasErrorOccurred()) 160 return; 161 unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error, 162 "cannot compile this %0 yet"); 163 std::string Msg = Type; 164 getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID) << Msg; 165 } 166 167 static llvm::GlobalValue::VisibilityTypes GetLLVMVisibility(Visibility V) { 168 switch (V) { 169 case DefaultVisibility: return llvm::GlobalValue::DefaultVisibility; 170 case HiddenVisibility: return llvm::GlobalValue::HiddenVisibility; 171 case ProtectedVisibility: return llvm::GlobalValue::ProtectedVisibility; 172 } 173 llvm_unreachable("unknown visibility!"); 174 return llvm::GlobalValue::DefaultVisibility; 175 } 176 177 178 void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV, 179 const NamedDecl *D, 180 bool IsForDefinition) const { 181 // Internal definitions always have default visibility. 182 if (GV->hasLocalLinkage()) { 183 GV->setVisibility(llvm::GlobalValue::DefaultVisibility); 184 return; 185 } 186 187 // Set visibility for definitions. 188 NamedDecl::LinkageInfo LV = D->getLinkageAndVisibility(); 189 if (LV.visibilityExplicit() || 190 (IsForDefinition && !GV->hasAvailableExternallyLinkage())) 191 GV->setVisibility(GetLLVMVisibility(LV.visibility())); 192 } 193 194 /// Set the symbol visibility of type information (vtable and RTTI) 195 /// associated with the given type. 196 void CodeGenModule::setTypeVisibility(llvm::GlobalValue *GV, 197 const CXXRecordDecl *RD, 198 bool IsForRTTI) const { 199 setGlobalVisibility(GV, RD, /*IsForDefinition=*/true); 200 201 if (!CodeGenOpts.HiddenWeakVTables) 202 return; 203 204 // We want to drop the visibility to hidden for weak type symbols. 205 // This isn't possible if there might be unresolved references 206 // elsewhere that rely on this symbol being visible. 207 208 // This should be kept roughly in sync with setThunkVisibility 209 // in CGVTables.cpp. 210 211 // Preconditions. 212 if (GV->getLinkage() != llvm::GlobalVariable::LinkOnceODRLinkage || 213 GV->getVisibility() != llvm::GlobalVariable::DefaultVisibility) 214 return; 215 216 // Don't override an explicit visibility attribute. 217 if (RD->hasAttr<VisibilityAttr>()) 218 return; 219 220 switch (RD->getTemplateSpecializationKind()) { 221 // We have to disable the optimization if this is an EI definition 222 // because there might be EI declarations in other shared objects. 223 case TSK_ExplicitInstantiationDefinition: 224 case TSK_ExplicitInstantiationDeclaration: 225 return; 226 227 // Every use of a non-template class's type information has to emit it. 228 case TSK_Undeclared: 229 break; 230 231 // In theory, implicit instantiations can ignore the possibility of 232 // an explicit instantiation declaration because there necessarily 233 // must be an EI definition somewhere with default visibility. In 234 // practice, it's possible to have an explicit instantiation for 235 // an arbitrary template class, and linkers aren't necessarily able 236 // to deal with mixed-visibility symbols. 237 case TSK_ExplicitSpecialization: 238 case TSK_ImplicitInstantiation: 239 if (!CodeGenOpts.HiddenWeakTemplateVTables) 240 return; 241 break; 242 } 243 244 // If there's a key function, there may be translation units 245 // that don't have the key function's definition. But ignore 246 // this if we're emitting RTTI under -fno-rtti. 247 if (!IsForRTTI || Features.RTTI) 248 if (Context.getKeyFunction(RD)) 249 return; 250 251 // Otherwise, drop the visibility to hidden. 252 GV->setVisibility(llvm::GlobalValue::HiddenVisibility); 253 GV->setUnnamedAddr(true); 254 } 255 256 llvm::StringRef CodeGenModule::getMangledName(GlobalDecl GD) { 257 const NamedDecl *ND = cast<NamedDecl>(GD.getDecl()); 258 259 llvm::StringRef &Str = MangledDeclNames[GD.getCanonicalDecl()]; 260 if (!Str.empty()) 261 return Str; 262 263 if (!getCXXABI().getMangleContext().shouldMangleDeclName(ND)) { 264 IdentifierInfo *II = ND->getIdentifier(); 265 assert(II && "Attempt to mangle unnamed decl."); 266 267 Str = II->getName(); 268 return Str; 269 } 270 271 llvm::SmallString<256> Buffer; 272 if (const CXXConstructorDecl *D = dyn_cast<CXXConstructorDecl>(ND)) 273 getCXXABI().getMangleContext().mangleCXXCtor(D, GD.getCtorType(), Buffer); 274 else if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(ND)) 275 getCXXABI().getMangleContext().mangleCXXDtor(D, GD.getDtorType(), Buffer); 276 else if (const BlockDecl *BD = dyn_cast<BlockDecl>(ND)) 277 getCXXABI().getMangleContext().mangleBlock(BD, Buffer); 278 else 279 getCXXABI().getMangleContext().mangleName(ND, Buffer); 280 281 // Allocate space for the mangled name. 282 size_t Length = Buffer.size(); 283 char *Name = MangledNamesAllocator.Allocate<char>(Length); 284 std::copy(Buffer.begin(), Buffer.end(), Name); 285 286 Str = llvm::StringRef(Name, Length); 287 288 return Str; 289 } 290 291 void CodeGenModule::getBlockMangledName(GlobalDecl GD, MangleBuffer &Buffer, 292 const BlockDecl *BD) { 293 MangleContext &MangleCtx = getCXXABI().getMangleContext(); 294 const Decl *D = GD.getDecl(); 295 if (D == 0) 296 MangleCtx.mangleGlobalBlock(BD, Buffer.getBuffer()); 297 else if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(D)) 298 MangleCtx.mangleCtorBlock(CD, GD.getCtorType(), BD, Buffer.getBuffer()); 299 else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(D)) 300 MangleCtx.mangleDtorBlock(DD, GD.getDtorType(), BD, Buffer.getBuffer()); 301 else 302 MangleCtx.mangleBlock(cast<DeclContext>(D), BD, Buffer.getBuffer()); 303 } 304 305 llvm::GlobalValue *CodeGenModule::GetGlobalValue(llvm::StringRef Name) { 306 return getModule().getNamedValue(Name); 307 } 308 309 /// AddGlobalCtor - Add a function to the list that will be called before 310 /// main() runs. 311 void CodeGenModule::AddGlobalCtor(llvm::Function * Ctor, int Priority) { 312 // FIXME: Type coercion of void()* types. 313 GlobalCtors.push_back(std::make_pair(Ctor, Priority)); 314 } 315 316 /// AddGlobalDtor - Add a function to the list that will be called 317 /// when the module is unloaded. 318 void CodeGenModule::AddGlobalDtor(llvm::Function * Dtor, int Priority) { 319 // FIXME: Type coercion of void()* types. 320 GlobalDtors.push_back(std::make_pair(Dtor, Priority)); 321 } 322 323 void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) { 324 // Ctor function type is void()*. 325 llvm::FunctionType* CtorFTy = 326 llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), false); 327 llvm::Type *CtorPFTy = llvm::PointerType::getUnqual(CtorFTy); 328 329 // Get the type of a ctor entry, { i32, void ()* }. 330 llvm::StructType* CtorStructTy = 331 llvm::StructType::get(VMContext, llvm::Type::getInt32Ty(VMContext), 332 llvm::PointerType::getUnqual(CtorFTy), NULL); 333 334 // Construct the constructor and destructor arrays. 335 std::vector<llvm::Constant*> Ctors; 336 for (CtorList::const_iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { 337 std::vector<llvm::Constant*> S; 338 S.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), 339 I->second, false)); 340 S.push_back(llvm::ConstantExpr::getBitCast(I->first, CtorPFTy)); 341 Ctors.push_back(llvm::ConstantStruct::get(CtorStructTy, S)); 342 } 343 344 if (!Ctors.empty()) { 345 llvm::ArrayType *AT = llvm::ArrayType::get(CtorStructTy, Ctors.size()); 346 new llvm::GlobalVariable(TheModule, AT, false, 347 llvm::GlobalValue::AppendingLinkage, 348 llvm::ConstantArray::get(AT, Ctors), 349 GlobalName); 350 } 351 } 352 353 void CodeGenModule::EmitAnnotations() { 354 if (Annotations.empty()) 355 return; 356 357 // Create a new global variable for the ConstantStruct in the Module. 358 llvm::Constant *Array = 359 llvm::ConstantArray::get(llvm::ArrayType::get(Annotations[0]->getType(), 360 Annotations.size()), 361 Annotations); 362 llvm::GlobalValue *gv = 363 new llvm::GlobalVariable(TheModule, Array->getType(), false, 364 llvm::GlobalValue::AppendingLinkage, Array, 365 "llvm.global.annotations"); 366 gv->setSection("llvm.metadata"); 367 } 368 369 llvm::GlobalValue::LinkageTypes 370 CodeGenModule::getFunctionLinkage(const FunctionDecl *D) { 371 GVALinkage Linkage = getContext().GetGVALinkageForFunction(D); 372 373 if (Linkage == GVA_Internal) 374 return llvm::Function::InternalLinkage; 375 376 if (D->hasAttr<DLLExportAttr>()) 377 return llvm::Function::DLLExportLinkage; 378 379 if (D->hasAttr<WeakAttr>()) 380 return llvm::Function::WeakAnyLinkage; 381 382 // In C99 mode, 'inline' functions are guaranteed to have a strong 383 // definition somewhere else, so we can use available_externally linkage. 384 if (Linkage == GVA_C99Inline) 385 return llvm::Function::AvailableExternallyLinkage; 386 387 // In C++, the compiler has to emit a definition in every translation unit 388 // that references the function. We should use linkonce_odr because 389 // a) if all references in this translation unit are optimized away, we 390 // don't need to codegen it. b) if the function persists, it needs to be 391 // merged with other definitions. c) C++ has the ODR, so we know the 392 // definition is dependable. 393 if (Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation) 394 return llvm::Function::LinkOnceODRLinkage; 395 396 // An explicit instantiation of a template has weak linkage, since 397 // explicit instantiations can occur in multiple translation units 398 // and must all be equivalent. However, we are not allowed to 399 // throw away these explicit instantiations. 400 if (Linkage == GVA_ExplicitTemplateInstantiation) 401 return llvm::Function::WeakODRLinkage; 402 403 // Otherwise, we have strong external linkage. 404 assert(Linkage == GVA_StrongExternal); 405 return llvm::Function::ExternalLinkage; 406 } 407 408 409 /// SetFunctionDefinitionAttributes - Set attributes for a global. 410 /// 411 /// FIXME: This is currently only done for aliases and functions, but not for 412 /// variables (these details are set in EmitGlobalVarDefinition for variables). 413 void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D, 414 llvm::GlobalValue *GV) { 415 SetCommonAttributes(D, GV); 416 } 417 418 void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D, 419 const CGFunctionInfo &Info, 420 llvm::Function *F) { 421 unsigned CallingConv; 422 AttributeListType AttributeList; 423 ConstructAttributeList(Info, D, AttributeList, CallingConv); 424 F->setAttributes(llvm::AttrListPtr::get(AttributeList.begin(), 425 AttributeList.size())); 426 F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv)); 427 } 428 429 void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D, 430 llvm::Function *F) { 431 if (!Features.Exceptions && !Features.ObjCNonFragileABI) 432 F->addFnAttr(llvm::Attribute::NoUnwind); 433 434 if (D->hasAttr<AlwaysInlineAttr>()) 435 F->addFnAttr(llvm::Attribute::AlwaysInline); 436 437 if (D->hasAttr<NakedAttr>()) 438 F->addFnAttr(llvm::Attribute::Naked); 439 440 if (D->hasAttr<NoInlineAttr>()) 441 F->addFnAttr(llvm::Attribute::NoInline); 442 443 if (isa<CXXConstructorDecl>(D) || isa<CXXDestructorDecl>(D)) 444 F->setUnnamedAddr(true); 445 446 if (Features.getStackProtectorMode() == LangOptions::SSPOn) 447 F->addFnAttr(llvm::Attribute::StackProtect); 448 else if (Features.getStackProtectorMode() == LangOptions::SSPReq) 449 F->addFnAttr(llvm::Attribute::StackProtectReq); 450 451 unsigned alignment = D->getMaxAlignment() / Context.getCharWidth(); 452 if (alignment) 453 F->setAlignment(alignment); 454 455 // C++ ABI requires 2-byte alignment for member functions. 456 if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D)) 457 F->setAlignment(2); 458 } 459 460 void CodeGenModule::SetCommonAttributes(const Decl *D, 461 llvm::GlobalValue *GV) { 462 if (isa<NamedDecl>(D)) 463 setGlobalVisibility(GV, cast<NamedDecl>(D), /*ForDef*/ true); 464 else 465 GV->setVisibility(llvm::GlobalValue::DefaultVisibility); 466 467 if (D->hasAttr<UsedAttr>()) 468 AddUsedGlobal(GV); 469 470 if (const SectionAttr *SA = D->getAttr<SectionAttr>()) 471 GV->setSection(SA->getName()); 472 473 getTargetCodeGenInfo().SetTargetAttributes(D, GV, *this); 474 } 475 476 void CodeGenModule::SetInternalFunctionAttributes(const Decl *D, 477 llvm::Function *F, 478 const CGFunctionInfo &FI) { 479 SetLLVMFunctionAttributes(D, FI, F); 480 SetLLVMFunctionAttributesForDefinition(D, F); 481 482 F->setLinkage(llvm::Function::InternalLinkage); 483 484 SetCommonAttributes(D, F); 485 } 486 487 void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, 488 llvm::Function *F, 489 bool IsIncompleteFunction) { 490 const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); 491 492 if (!IsIncompleteFunction) 493 SetLLVMFunctionAttributes(FD, getTypes().getFunctionInfo(GD), F); 494 495 // Only a few attributes are set on declarations; these may later be 496 // overridden by a definition. 497 498 if (FD->hasAttr<DLLImportAttr>()) { 499 F->setLinkage(llvm::Function::DLLImportLinkage); 500 } else if (FD->hasAttr<WeakAttr>() || 501 FD->hasAttr<WeakImportAttr>()) { 502 // "extern_weak" is overloaded in LLVM; we probably should have 503 // separate linkage types for this. 504 F->setLinkage(llvm::Function::ExternalWeakLinkage); 505 } else { 506 F->setLinkage(llvm::Function::ExternalLinkage); 507 508 NamedDecl::LinkageInfo LV = FD->getLinkageAndVisibility(); 509 if (LV.linkage() == ExternalLinkage && LV.visibilityExplicit()) { 510 F->setVisibility(GetLLVMVisibility(LV.visibility())); 511 } 512 } 513 514 if (const SectionAttr *SA = FD->getAttr<SectionAttr>()) 515 F->setSection(SA->getName()); 516 } 517 518 void CodeGenModule::AddUsedGlobal(llvm::GlobalValue *GV) { 519 assert(!GV->isDeclaration() && 520 "Only globals with definition can force usage."); 521 LLVMUsed.push_back(GV); 522 } 523 524 void CodeGenModule::EmitLLVMUsed() { 525 // Don't create llvm.used if there is no need. 526 if (LLVMUsed.empty()) 527 return; 528 529 const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext); 530 531 // Convert LLVMUsed to what ConstantArray needs. 532 std::vector<llvm::Constant*> UsedArray; 533 UsedArray.resize(LLVMUsed.size()); 534 for (unsigned i = 0, e = LLVMUsed.size(); i != e; ++i) { 535 UsedArray[i] = 536 llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(&*LLVMUsed[i]), 537 i8PTy); 538 } 539 540 if (UsedArray.empty()) 541 return; 542 llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, UsedArray.size()); 543 544 llvm::GlobalVariable *GV = 545 new llvm::GlobalVariable(getModule(), ATy, false, 546 llvm::GlobalValue::AppendingLinkage, 547 llvm::ConstantArray::get(ATy, UsedArray), 548 "llvm.used"); 549 550 GV->setSection("llvm.metadata"); 551 } 552 553 void CodeGenModule::EmitDeferred() { 554 // Emit code for any potentially referenced deferred decls. Since a 555 // previously unused static decl may become used during the generation of code 556 // for a static function, iterate until no changes are made. 557 558 while (!DeferredDeclsToEmit.empty() || !DeferredVTables.empty()) { 559 if (!DeferredVTables.empty()) { 560 const CXXRecordDecl *RD = DeferredVTables.back(); 561 DeferredVTables.pop_back(); 562 getVTables().GenerateClassData(getVTableLinkage(RD), RD); 563 continue; 564 } 565 566 GlobalDecl D = DeferredDeclsToEmit.back(); 567 DeferredDeclsToEmit.pop_back(); 568 569 // Check to see if we've already emitted this. This is necessary 570 // for a couple of reasons: first, decls can end up in the 571 // deferred-decls queue multiple times, and second, decls can end 572 // up with definitions in unusual ways (e.g. by an extern inline 573 // function acquiring a strong function redefinition). Just 574 // ignore these cases. 575 // 576 // TODO: That said, looking this up multiple times is very wasteful. 577 llvm::StringRef Name = getMangledName(D); 578 llvm::GlobalValue *CGRef = GetGlobalValue(Name); 579 assert(CGRef && "Deferred decl wasn't referenced?"); 580 581 if (!CGRef->isDeclaration()) 582 continue; 583 584 // GlobalAlias::isDeclaration() defers to the aliasee, but for our 585 // purposes an alias counts as a definition. 586 if (isa<llvm::GlobalAlias>(CGRef)) 587 continue; 588 589 // Otherwise, emit the definition and move on to the next one. 590 EmitGlobalDefinition(D); 591 } 592 } 593 594 /// EmitAnnotateAttr - Generate the llvm::ConstantStruct which contains the 595 /// annotation information for a given GlobalValue. The annotation struct is 596 /// {i8 *, i8 *, i8 *, i32}. The first field is a constant expression, the 597 /// GlobalValue being annotated. The second field is the constant string 598 /// created from the AnnotateAttr's annotation. The third field is a constant 599 /// string containing the name of the translation unit. The fourth field is 600 /// the line number in the file of the annotated value declaration. 601 /// 602 /// FIXME: this does not unique the annotation string constants, as llvm-gcc 603 /// appears to. 604 /// 605 llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV, 606 const AnnotateAttr *AA, 607 unsigned LineNo) { 608 llvm::Module *M = &getModule(); 609 610 // get [N x i8] constants for the annotation string, and the filename string 611 // which are the 2nd and 3rd elements of the global annotation structure. 612 const llvm::Type *SBP = llvm::Type::getInt8PtrTy(VMContext); 613 llvm::Constant *anno = llvm::ConstantArray::get(VMContext, 614 AA->getAnnotation(), true); 615 llvm::Constant *unit = llvm::ConstantArray::get(VMContext, 616 M->getModuleIdentifier(), 617 true); 618 619 // Get the two global values corresponding to the ConstantArrays we just 620 // created to hold the bytes of the strings. 621 llvm::GlobalValue *annoGV = 622 new llvm::GlobalVariable(*M, anno->getType(), false, 623 llvm::GlobalValue::PrivateLinkage, anno, 624 GV->getName()); 625 // translation unit name string, emitted into the llvm.metadata section. 626 llvm::GlobalValue *unitGV = 627 new llvm::GlobalVariable(*M, unit->getType(), false, 628 llvm::GlobalValue::PrivateLinkage, unit, 629 ".str"); 630 unitGV->setUnnamedAddr(true); 631 632 // Create the ConstantStruct for the global annotation. 633 llvm::Constant *Fields[4] = { 634 llvm::ConstantExpr::getBitCast(GV, SBP), 635 llvm::ConstantExpr::getBitCast(annoGV, SBP), 636 llvm::ConstantExpr::getBitCast(unitGV, SBP), 637 llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), LineNo) 638 }; 639 return llvm::ConstantStruct::get(VMContext, Fields, 4, false); 640 } 641 642 bool CodeGenModule::MayDeferGeneration(const ValueDecl *Global) { 643 // Never defer when EmitAllDecls is specified. 644 if (Features.EmitAllDecls) 645 return false; 646 647 return !getContext().DeclMustBeEmitted(Global); 648 } 649 650 llvm::Constant *CodeGenModule::GetWeakRefReference(const ValueDecl *VD) { 651 const AliasAttr *AA = VD->getAttr<AliasAttr>(); 652 assert(AA && "No alias?"); 653 654 const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType()); 655 656 // See if there is already something with the target's name in the module. 657 llvm::GlobalValue *Entry = GetGlobalValue(AA->getAliasee()); 658 659 llvm::Constant *Aliasee; 660 if (isa<llvm::FunctionType>(DeclTy)) 661 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl()); 662 else 663 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 664 llvm::PointerType::getUnqual(DeclTy), 0); 665 if (!Entry) { 666 llvm::GlobalValue* F = cast<llvm::GlobalValue>(Aliasee); 667 F->setLinkage(llvm::Function::ExternalWeakLinkage); 668 WeakRefReferences.insert(F); 669 } 670 671 return Aliasee; 672 } 673 674 void CodeGenModule::EmitGlobal(GlobalDecl GD) { 675 const ValueDecl *Global = cast<ValueDecl>(GD.getDecl()); 676 677 // Weak references don't produce any output by themselves. 678 if (Global->hasAttr<WeakRefAttr>()) 679 return; 680 681 // If this is an alias definition (which otherwise looks like a declaration) 682 // emit it now. 683 if (Global->hasAttr<AliasAttr>()) 684 return EmitAliasDefinition(GD); 685 686 // Ignore declarations, they will be emitted on their first use. 687 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) { 688 if (FD->getIdentifier()) { 689 llvm::StringRef Name = FD->getName(); 690 if (Name == "_Block_object_assign") { 691 BlockObjectAssignDecl = FD; 692 } else if (Name == "_Block_object_dispose") { 693 BlockObjectDisposeDecl = FD; 694 } 695 } 696 697 // Forward declarations are emitted lazily on first use. 698 if (!FD->isThisDeclarationADefinition()) 699 return; 700 } else { 701 const VarDecl *VD = cast<VarDecl>(Global); 702 assert(VD->isFileVarDecl() && "Cannot emit local var decl as global."); 703 704 if (VD->getIdentifier()) { 705 llvm::StringRef Name = VD->getName(); 706 if (Name == "_NSConcreteGlobalBlock") { 707 NSConcreteGlobalBlockDecl = VD; 708 } else if (Name == "_NSConcreteStackBlock") { 709 NSConcreteStackBlockDecl = VD; 710 } 711 } 712 713 714 if (VD->isThisDeclarationADefinition() != VarDecl::Definition) 715 return; 716 } 717 718 // Defer code generation when possible if this is a static definition, inline 719 // function etc. These we only want to emit if they are used. 720 if (!MayDeferGeneration(Global)) { 721 // Emit the definition if it can't be deferred. 722 EmitGlobalDefinition(GD); 723 return; 724 } 725 726 // If we're deferring emission of a C++ variable with an 727 // initializer, remember the order in which it appeared in the file. 728 if (getLangOptions().CPlusPlus && isa<VarDecl>(Global) && 729 cast<VarDecl>(Global)->hasInit()) { 730 DelayedCXXInitPosition[Global] = CXXGlobalInits.size(); 731 CXXGlobalInits.push_back(0); 732 } 733 734 // If the value has already been used, add it directly to the 735 // DeferredDeclsToEmit list. 736 llvm::StringRef MangledName = getMangledName(GD); 737 if (GetGlobalValue(MangledName)) 738 DeferredDeclsToEmit.push_back(GD); 739 else { 740 // Otherwise, remember that we saw a deferred decl with this name. The 741 // first use of the mangled name will cause it to move into 742 // DeferredDeclsToEmit. 743 DeferredDecls[MangledName] = GD; 744 } 745 } 746 747 void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) { 748 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 749 750 PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(), 751 Context.getSourceManager(), 752 "Generating code for declaration"); 753 754 if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) { 755 // At -O0, don't generate IR for functions with available_externally 756 // linkage. 757 if (CodeGenOpts.OptimizationLevel == 0 && 758 !Function->hasAttr<AlwaysInlineAttr>() && 759 getFunctionLinkage(Function) 760 == llvm::Function::AvailableExternallyLinkage) 761 return; 762 763 if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) { 764 if (Method->isVirtual()) 765 getVTables().EmitThunks(GD); 766 767 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Method)) 768 return EmitCXXConstructor(CD, GD.getCtorType()); 769 770 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(Method)) 771 return EmitCXXDestructor(DD, GD.getDtorType()); 772 } 773 774 return EmitGlobalFunctionDefinition(GD); 775 } 776 777 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 778 return EmitGlobalVarDefinition(VD); 779 780 assert(0 && "Invalid argument to EmitGlobalDefinition()"); 781 } 782 783 /// GetOrCreateLLVMFunction - If the specified mangled name is not in the 784 /// module, create and return an llvm Function with the specified type. If there 785 /// is something in the module with the specified name, return it potentially 786 /// bitcasted to the right type. 787 /// 788 /// If D is non-null, it specifies a decl that correspond to this. This is used 789 /// to set the attributes on the function when it is first created. 790 llvm::Constant * 791 CodeGenModule::GetOrCreateLLVMFunction(llvm::StringRef MangledName, 792 const llvm::Type *Ty, 793 GlobalDecl D) { 794 // Lookup the entry, lazily creating it if necessary. 795 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 796 if (Entry) { 797 if (WeakRefReferences.count(Entry)) { 798 const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl()); 799 if (FD && !FD->hasAttr<WeakAttr>()) 800 Entry->setLinkage(llvm::Function::ExternalLinkage); 801 802 WeakRefReferences.erase(Entry); 803 } 804 805 if (Entry->getType()->getElementType() == Ty) 806 return Entry; 807 808 // Make sure the result is of the correct type. 809 const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 810 return llvm::ConstantExpr::getBitCast(Entry, PTy); 811 } 812 813 // This function doesn't have a complete type (for example, the return 814 // type is an incomplete struct). Use a fake type instead, and make 815 // sure not to try to set attributes. 816 bool IsIncompleteFunction = false; 817 818 const llvm::FunctionType *FTy; 819 if (isa<llvm::FunctionType>(Ty)) { 820 FTy = cast<llvm::FunctionType>(Ty); 821 } else { 822 FTy = llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), false); 823 IsIncompleteFunction = true; 824 } 825 826 llvm::Function *F = llvm::Function::Create(FTy, 827 llvm::Function::ExternalLinkage, 828 MangledName, &getModule()); 829 assert(F->getName() == MangledName && "name was uniqued!"); 830 if (D.getDecl()) 831 SetFunctionAttributes(D, F, IsIncompleteFunction); 832 833 // This is the first use or definition of a mangled name. If there is a 834 // deferred decl with this name, remember that we need to emit it at the end 835 // of the file. 836 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 837 if (DDI != DeferredDecls.end()) { 838 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 839 // list, and remove it from DeferredDecls (since we don't need it anymore). 840 DeferredDeclsToEmit.push_back(DDI->second); 841 DeferredDecls.erase(DDI); 842 843 // Otherwise, there are cases we have to worry about where we're 844 // using a declaration for which we must emit a definition but where 845 // we might not find a top-level definition: 846 // - member functions defined inline in their classes 847 // - friend functions defined inline in some class 848 // - special member functions with implicit definitions 849 // If we ever change our AST traversal to walk into class methods, 850 // this will be unnecessary. 851 } else if (getLangOptions().CPlusPlus && D.getDecl()) { 852 // Look for a declaration that's lexically in a record. 853 const FunctionDecl *FD = cast<FunctionDecl>(D.getDecl()); 854 do { 855 if (isa<CXXRecordDecl>(FD->getLexicalDeclContext())) { 856 if (FD->isImplicit()) { 857 assert(FD->isUsed() && "Sema didn't mark implicit function as used!"); 858 DeferredDeclsToEmit.push_back(D); 859 break; 860 } else if (FD->isThisDeclarationADefinition()) { 861 DeferredDeclsToEmit.push_back(D); 862 break; 863 } 864 } 865 FD = FD->getPreviousDeclaration(); 866 } while (FD); 867 } 868 869 // Make sure the result is of the requested type. 870 if (!IsIncompleteFunction) { 871 assert(F->getType()->getElementType() == Ty); 872 return F; 873 } 874 875 const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty); 876 return llvm::ConstantExpr::getBitCast(F, PTy); 877 } 878 879 /// GetAddrOfFunction - Return the address of the given function. If Ty is 880 /// non-null, then this function will use the specified type if it has to 881 /// create it (this occurs when we see a definition of the function). 882 llvm::Constant *CodeGenModule::GetAddrOfFunction(GlobalDecl GD, 883 const llvm::Type *Ty) { 884 // If there was no specific requested type, just convert it now. 885 if (!Ty) 886 Ty = getTypes().ConvertType(cast<ValueDecl>(GD.getDecl())->getType()); 887 888 llvm::StringRef MangledName = getMangledName(GD); 889 return GetOrCreateLLVMFunction(MangledName, Ty, GD); 890 } 891 892 /// CreateRuntimeFunction - Create a new runtime function with the specified 893 /// type and name. 894 llvm::Constant * 895 CodeGenModule::CreateRuntimeFunction(const llvm::FunctionType *FTy, 896 llvm::StringRef Name) { 897 return GetOrCreateLLVMFunction(Name, FTy, GlobalDecl()); 898 } 899 900 static bool DeclIsConstantGlobal(ASTContext &Context, const VarDecl *D) { 901 if (!D->getType().isConstant(Context) && !D->getType()->isReferenceType()) 902 return false; 903 if (Context.getLangOptions().CPlusPlus && 904 Context.getBaseElementType(D->getType())->getAs<RecordType>()) { 905 // FIXME: We should do something fancier here! 906 return false; 907 } 908 return true; 909 } 910 911 /// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module, 912 /// create and return an llvm GlobalVariable with the specified type. If there 913 /// is something in the module with the specified name, return it potentially 914 /// bitcasted to the right type. 915 /// 916 /// If D is non-null, it specifies a decl that correspond to this. This is used 917 /// to set the attributes on the global when it is first created. 918 llvm::Constant * 919 CodeGenModule::GetOrCreateLLVMGlobal(llvm::StringRef MangledName, 920 const llvm::PointerType *Ty, 921 const VarDecl *D, 922 bool UnnamedAddr) { 923 // Lookup the entry, lazily creating it if necessary. 924 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 925 if (Entry) { 926 if (WeakRefReferences.count(Entry)) { 927 if (D && !D->hasAttr<WeakAttr>()) 928 Entry->setLinkage(llvm::Function::ExternalLinkage); 929 930 WeakRefReferences.erase(Entry); 931 } 932 933 if (UnnamedAddr) 934 Entry->setUnnamedAddr(true); 935 936 if (Entry->getType() == Ty) 937 return Entry; 938 939 // Make sure the result is of the correct type. 940 return llvm::ConstantExpr::getBitCast(Entry, Ty); 941 } 942 943 // This is the first use or definition of a mangled name. If there is a 944 // deferred decl with this name, remember that we need to emit it at the end 945 // of the file. 946 llvm::StringMap<GlobalDecl>::iterator DDI = DeferredDecls.find(MangledName); 947 if (DDI != DeferredDecls.end()) { 948 // Move the potentially referenced deferred decl to the DeferredDeclsToEmit 949 // list, and remove it from DeferredDecls (since we don't need it anymore). 950 DeferredDeclsToEmit.push_back(DDI->second); 951 DeferredDecls.erase(DDI); 952 } 953 954 llvm::GlobalVariable *GV = 955 new llvm::GlobalVariable(getModule(), Ty->getElementType(), false, 956 llvm::GlobalValue::ExternalLinkage, 957 0, MangledName, 0, 958 false, Ty->getAddressSpace()); 959 960 // Handle things which are present even on external declarations. 961 if (D) { 962 // FIXME: This code is overly simple and should be merged with other global 963 // handling. 964 GV->setConstant(DeclIsConstantGlobal(Context, D)); 965 966 // Set linkage and visibility in case we never see a definition. 967 NamedDecl::LinkageInfo LV = D->getLinkageAndVisibility(); 968 if (LV.linkage() != ExternalLinkage) { 969 GV->setLinkage(llvm::GlobalValue::InternalLinkage); 970 } else { 971 if (D->hasAttr<DLLImportAttr>()) 972 GV->setLinkage(llvm::GlobalValue::DLLImportLinkage); 973 else if (D->hasAttr<WeakAttr>() || D->hasAttr<WeakImportAttr>()) 974 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage); 975 976 // Set visibility on a declaration only if it's explicit. 977 if (LV.visibilityExplicit()) 978 GV->setVisibility(GetLLVMVisibility(LV.visibility())); 979 } 980 981 GV->setThreadLocal(D->isThreadSpecified()); 982 } 983 984 return GV; 985 } 986 987 988 /// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the 989 /// given global variable. If Ty is non-null and if the global doesn't exist, 990 /// then it will be greated with the specified type instead of whatever the 991 /// normal requested type would be. 992 llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D, 993 const llvm::Type *Ty) { 994 assert(D->hasGlobalStorage() && "Not a global variable"); 995 QualType ASTTy = D->getType(); 996 if (Ty == 0) 997 Ty = getTypes().ConvertTypeForMem(ASTTy); 998 999 const llvm::PointerType *PTy = 1000 llvm::PointerType::get(Ty, ASTTy.getAddressSpace()); 1001 1002 llvm::StringRef MangledName = getMangledName(D); 1003 return GetOrCreateLLVMGlobal(MangledName, PTy, D); 1004 } 1005 1006 /// CreateRuntimeVariable - Create a new runtime global variable with the 1007 /// specified type and name. 1008 llvm::Constant * 1009 CodeGenModule::CreateRuntimeVariable(const llvm::Type *Ty, 1010 llvm::StringRef Name) { 1011 return GetOrCreateLLVMGlobal(Name, llvm::PointerType::getUnqual(Ty), 0, 1012 true); 1013 } 1014 1015 void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) { 1016 assert(!D->getInit() && "Cannot emit definite definitions here!"); 1017 1018 if (MayDeferGeneration(D)) { 1019 // If we have not seen a reference to this variable yet, place it 1020 // into the deferred declarations table to be emitted if needed 1021 // later. 1022 llvm::StringRef MangledName = getMangledName(D); 1023 if (!GetGlobalValue(MangledName)) { 1024 DeferredDecls[MangledName] = D; 1025 return; 1026 } 1027 } 1028 1029 // The tentative definition is the only definition. 1030 EmitGlobalVarDefinition(D); 1031 } 1032 1033 void CodeGenModule::EmitVTable(CXXRecordDecl *Class, bool DefinitionRequired) { 1034 if (DefinitionRequired) 1035 getVTables().GenerateClassData(getVTableLinkage(Class), Class); 1036 } 1037 1038 llvm::GlobalVariable::LinkageTypes 1039 CodeGenModule::getVTableLinkage(const CXXRecordDecl *RD) { 1040 if (RD->isInAnonymousNamespace() || !RD->hasLinkage()) 1041 return llvm::GlobalVariable::InternalLinkage; 1042 1043 if (const CXXMethodDecl *KeyFunction 1044 = RD->getASTContext().getKeyFunction(RD)) { 1045 // If this class has a key function, use that to determine the linkage of 1046 // the vtable. 1047 const FunctionDecl *Def = 0; 1048 if (KeyFunction->hasBody(Def)) 1049 KeyFunction = cast<CXXMethodDecl>(Def); 1050 1051 switch (KeyFunction->getTemplateSpecializationKind()) { 1052 case TSK_Undeclared: 1053 case TSK_ExplicitSpecialization: 1054 if (KeyFunction->isInlined()) 1055 return llvm::GlobalVariable::LinkOnceODRLinkage; 1056 1057 return llvm::GlobalVariable::ExternalLinkage; 1058 1059 case TSK_ImplicitInstantiation: 1060 return llvm::GlobalVariable::LinkOnceODRLinkage; 1061 1062 case TSK_ExplicitInstantiationDefinition: 1063 return llvm::GlobalVariable::WeakODRLinkage; 1064 1065 case TSK_ExplicitInstantiationDeclaration: 1066 // FIXME: Use available_externally linkage. However, this currently 1067 // breaks LLVM's build due to undefined symbols. 1068 // return llvm::GlobalVariable::AvailableExternallyLinkage; 1069 return llvm::GlobalVariable::LinkOnceODRLinkage; 1070 } 1071 } 1072 1073 switch (RD->getTemplateSpecializationKind()) { 1074 case TSK_Undeclared: 1075 case TSK_ExplicitSpecialization: 1076 case TSK_ImplicitInstantiation: 1077 return llvm::GlobalVariable::LinkOnceODRLinkage; 1078 1079 case TSK_ExplicitInstantiationDefinition: 1080 return llvm::GlobalVariable::WeakODRLinkage; 1081 1082 case TSK_ExplicitInstantiationDeclaration: 1083 // FIXME: Use available_externally linkage. However, this currently 1084 // breaks LLVM's build due to undefined symbols. 1085 // return llvm::GlobalVariable::AvailableExternallyLinkage; 1086 return llvm::GlobalVariable::LinkOnceODRLinkage; 1087 } 1088 1089 // Silence GCC warning. 1090 return llvm::GlobalVariable::LinkOnceODRLinkage; 1091 } 1092 1093 CharUnits CodeGenModule::GetTargetTypeStoreSize(const llvm::Type *Ty) const { 1094 return Context.toCharUnitsFromBits( 1095 TheTargetData.getTypeStoreSizeInBits(Ty)); 1096 } 1097 1098 void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) { 1099 llvm::Constant *Init = 0; 1100 QualType ASTTy = D->getType(); 1101 bool NonConstInit = false; 1102 1103 const Expr *InitExpr = D->getAnyInitializer(); 1104 1105 if (!InitExpr) { 1106 // This is a tentative definition; tentative definitions are 1107 // implicitly initialized with { 0 }. 1108 // 1109 // Note that tentative definitions are only emitted at the end of 1110 // a translation unit, so they should never have incomplete 1111 // type. In addition, EmitTentativeDefinition makes sure that we 1112 // never attempt to emit a tentative definition if a real one 1113 // exists. A use may still exists, however, so we still may need 1114 // to do a RAUW. 1115 assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type"); 1116 Init = EmitNullConstant(D->getType()); 1117 } else { 1118 Init = EmitConstantExpr(InitExpr, D->getType()); 1119 if (!Init) { 1120 QualType T = InitExpr->getType(); 1121 if (D->getType()->isReferenceType()) 1122 T = D->getType(); 1123 1124 if (getLangOptions().CPlusPlus) { 1125 Init = EmitNullConstant(T); 1126 NonConstInit = true; 1127 } else { 1128 ErrorUnsupported(D, "static initializer"); 1129 Init = llvm::UndefValue::get(getTypes().ConvertType(T)); 1130 } 1131 } else { 1132 // We don't need an initializer, so remove the entry for the delayed 1133 // initializer position (just in case this entry was delayed). 1134 if (getLangOptions().CPlusPlus) 1135 DelayedCXXInitPosition.erase(D); 1136 } 1137 } 1138 1139 const llvm::Type* InitType = Init->getType(); 1140 llvm::Constant *Entry = GetAddrOfGlobalVar(D, InitType); 1141 1142 // Strip off a bitcast if we got one back. 1143 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 1144 assert(CE->getOpcode() == llvm::Instruction::BitCast || 1145 // all zero index gep. 1146 CE->getOpcode() == llvm::Instruction::GetElementPtr); 1147 Entry = CE->getOperand(0); 1148 } 1149 1150 // Entry is now either a Function or GlobalVariable. 1151 llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Entry); 1152 1153 // We have a definition after a declaration with the wrong type. 1154 // We must make a new GlobalVariable* and update everything that used OldGV 1155 // (a declaration or tentative definition) with the new GlobalVariable* 1156 // (which will be a definition). 1157 // 1158 // This happens if there is a prototype for a global (e.g. 1159 // "extern int x[];") and then a definition of a different type (e.g. 1160 // "int x[10];"). This also happens when an initializer has a different type 1161 // from the type of the global (this happens with unions). 1162 if (GV == 0 || 1163 GV->getType()->getElementType() != InitType || 1164 GV->getType()->getAddressSpace() != ASTTy.getAddressSpace()) { 1165 1166 // Move the old entry aside so that we'll create a new one. 1167 Entry->setName(llvm::StringRef()); 1168 1169 // Make a new global with the correct type, this is now guaranteed to work. 1170 GV = cast<llvm::GlobalVariable>(GetAddrOfGlobalVar(D, InitType)); 1171 1172 // Replace all uses of the old global with the new global 1173 llvm::Constant *NewPtrForOldDecl = 1174 llvm::ConstantExpr::getBitCast(GV, Entry->getType()); 1175 Entry->replaceAllUsesWith(NewPtrForOldDecl); 1176 1177 // Erase the old global, since it is no longer used. 1178 cast<llvm::GlobalValue>(Entry)->eraseFromParent(); 1179 } 1180 1181 if (const AnnotateAttr *AA = D->getAttr<AnnotateAttr>()) { 1182 SourceManager &SM = Context.getSourceManager(); 1183 AddAnnotation(EmitAnnotateAttr(GV, AA, 1184 SM.getInstantiationLineNumber(D->getLocation()))); 1185 } 1186 1187 GV->setInitializer(Init); 1188 1189 // If it is safe to mark the global 'constant', do so now. 1190 GV->setConstant(false); 1191 if (!NonConstInit && DeclIsConstantGlobal(Context, D)) 1192 GV->setConstant(true); 1193 1194 GV->setAlignment(getContext().getDeclAlign(D).getQuantity()); 1195 1196 // Set the llvm linkage type as appropriate. 1197 llvm::GlobalValue::LinkageTypes Linkage = 1198 GetLLVMLinkageVarDefinition(D, GV); 1199 GV->setLinkage(Linkage); 1200 if (Linkage == llvm::GlobalVariable::CommonLinkage) 1201 // common vars aren't constant even if declared const. 1202 GV->setConstant(false); 1203 1204 SetCommonAttributes(D, GV); 1205 1206 // Emit the initializer function if necessary. 1207 if (NonConstInit) 1208 EmitCXXGlobalVarDeclInitFunc(D, GV); 1209 1210 // Emit global variable debug information. 1211 if (CGDebugInfo *DI = getDebugInfo()) { 1212 DI->setLocation(D->getLocation()); 1213 DI->EmitGlobalVariable(GV, D); 1214 } 1215 } 1216 1217 llvm::GlobalValue::LinkageTypes 1218 CodeGenModule::GetLLVMLinkageVarDefinition(const VarDecl *D, 1219 llvm::GlobalVariable *GV) { 1220 GVALinkage Linkage = getContext().GetGVALinkageForVariable(D); 1221 if (Linkage == GVA_Internal) 1222 return llvm::Function::InternalLinkage; 1223 else if (D->hasAttr<DLLImportAttr>()) 1224 return llvm::Function::DLLImportLinkage; 1225 else if (D->hasAttr<DLLExportAttr>()) 1226 return llvm::Function::DLLExportLinkage; 1227 else if (D->hasAttr<WeakAttr>()) { 1228 if (GV->isConstant()) 1229 return llvm::GlobalVariable::WeakODRLinkage; 1230 else 1231 return llvm::GlobalVariable::WeakAnyLinkage; 1232 } else if (Linkage == GVA_TemplateInstantiation || 1233 Linkage == GVA_ExplicitTemplateInstantiation) 1234 // FIXME: It seems like we can provide more specific linkage here 1235 // (LinkOnceODR, WeakODR). 1236 return llvm::GlobalVariable::WeakAnyLinkage; 1237 else if (!getLangOptions().CPlusPlus && 1238 ((!CodeGenOpts.NoCommon && !D->getAttr<NoCommonAttr>()) || 1239 D->getAttr<CommonAttr>()) && 1240 !D->hasExternalStorage() && !D->getInit() && 1241 !D->getAttr<SectionAttr>() && !D->isThreadSpecified()) { 1242 // Thread local vars aren't considered common linkage. 1243 return llvm::GlobalVariable::CommonLinkage; 1244 } 1245 return llvm::GlobalVariable::ExternalLinkage; 1246 } 1247 1248 /// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we 1249 /// implement a function with no prototype, e.g. "int foo() {}". If there are 1250 /// existing call uses of the old function in the module, this adjusts them to 1251 /// call the new function directly. 1252 /// 1253 /// This is not just a cleanup: the always_inline pass requires direct calls to 1254 /// functions to be able to inline them. If there is a bitcast in the way, it 1255 /// won't inline them. Instcombine normally deletes these calls, but it isn't 1256 /// run at -O0. 1257 static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old, 1258 llvm::Function *NewFn) { 1259 // If we're redefining a global as a function, don't transform it. 1260 llvm::Function *OldFn = dyn_cast<llvm::Function>(Old); 1261 if (OldFn == 0) return; 1262 1263 const llvm::Type *NewRetTy = NewFn->getReturnType(); 1264 llvm::SmallVector<llvm::Value*, 4> ArgList; 1265 1266 for (llvm::Value::use_iterator UI = OldFn->use_begin(), E = OldFn->use_end(); 1267 UI != E; ) { 1268 // TODO: Do invokes ever occur in C code? If so, we should handle them too. 1269 llvm::Value::use_iterator I = UI++; // Increment before the CI is erased. 1270 llvm::CallInst *CI = dyn_cast<llvm::CallInst>(*I); 1271 if (!CI) continue; // FIXME: when we allow Invoke, just do CallSite CS(*I) 1272 llvm::CallSite CS(CI); 1273 if (!CI || !CS.isCallee(I)) continue; 1274 1275 // If the return types don't match exactly, and if the call isn't dead, then 1276 // we can't transform this call. 1277 if (CI->getType() != NewRetTy && !CI->use_empty()) 1278 continue; 1279 1280 // If the function was passed too few arguments, don't transform. If extra 1281 // arguments were passed, we silently drop them. If any of the types 1282 // mismatch, we don't transform. 1283 unsigned ArgNo = 0; 1284 bool DontTransform = false; 1285 for (llvm::Function::arg_iterator AI = NewFn->arg_begin(), 1286 E = NewFn->arg_end(); AI != E; ++AI, ++ArgNo) { 1287 if (CS.arg_size() == ArgNo || 1288 CS.getArgument(ArgNo)->getType() != AI->getType()) { 1289 DontTransform = true; 1290 break; 1291 } 1292 } 1293 if (DontTransform) 1294 continue; 1295 1296 // Okay, we can transform this. Create the new call instruction and copy 1297 // over the required information. 1298 ArgList.append(CS.arg_begin(), CS.arg_begin() + ArgNo); 1299 llvm::CallInst *NewCall = llvm::CallInst::Create(NewFn, ArgList.begin(), 1300 ArgList.end(), "", CI); 1301 ArgList.clear(); 1302 if (!NewCall->getType()->isVoidTy()) 1303 NewCall->takeName(CI); 1304 NewCall->setAttributes(CI->getAttributes()); 1305 NewCall->setCallingConv(CI->getCallingConv()); 1306 1307 // Finally, remove the old call, replacing any uses with the new one. 1308 if (!CI->use_empty()) 1309 CI->replaceAllUsesWith(NewCall); 1310 1311 // Copy debug location attached to CI. 1312 if (!CI->getDebugLoc().isUnknown()) 1313 NewCall->setDebugLoc(CI->getDebugLoc()); 1314 CI->eraseFromParent(); 1315 } 1316 } 1317 1318 1319 void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD) { 1320 const FunctionDecl *D = cast<FunctionDecl>(GD.getDecl()); 1321 const llvm::FunctionType *Ty = getTypes().GetFunctionType(GD); 1322 // Get or create the prototype for the function. 1323 llvm::Constant *Entry = GetAddrOfFunction(GD, Ty); 1324 1325 // Strip off a bitcast if we got one back. 1326 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Entry)) { 1327 assert(CE->getOpcode() == llvm::Instruction::BitCast); 1328 Entry = CE->getOperand(0); 1329 } 1330 1331 1332 if (cast<llvm::GlobalValue>(Entry)->getType()->getElementType() != Ty) { 1333 llvm::GlobalValue *OldFn = cast<llvm::GlobalValue>(Entry); 1334 1335 // If the types mismatch then we have to rewrite the definition. 1336 assert(OldFn->isDeclaration() && 1337 "Shouldn't replace non-declaration"); 1338 1339 // F is the Function* for the one with the wrong type, we must make a new 1340 // Function* and update everything that used F (a declaration) with the new 1341 // Function* (which will be a definition). 1342 // 1343 // This happens if there is a prototype for a function 1344 // (e.g. "int f()") and then a definition of a different type 1345 // (e.g. "int f(int x)"). Move the old function aside so that it 1346 // doesn't interfere with GetAddrOfFunction. 1347 OldFn->setName(llvm::StringRef()); 1348 llvm::Function *NewFn = cast<llvm::Function>(GetAddrOfFunction(GD, Ty)); 1349 1350 // If this is an implementation of a function without a prototype, try to 1351 // replace any existing uses of the function (which may be calls) with uses 1352 // of the new function 1353 if (D->getType()->isFunctionNoProtoType()) { 1354 ReplaceUsesOfNonProtoTypeWithRealFunction(OldFn, NewFn); 1355 OldFn->removeDeadConstantUsers(); 1356 } 1357 1358 // Replace uses of F with the Function we will endow with a body. 1359 if (!Entry->use_empty()) { 1360 llvm::Constant *NewPtrForOldDecl = 1361 llvm::ConstantExpr::getBitCast(NewFn, Entry->getType()); 1362 Entry->replaceAllUsesWith(NewPtrForOldDecl); 1363 } 1364 1365 // Ok, delete the old function now, which is dead. 1366 OldFn->eraseFromParent(); 1367 1368 Entry = NewFn; 1369 } 1370 1371 // We need to set linkage and visibility on the function before 1372 // generating code for it because various parts of IR generation 1373 // want to propagate this information down (e.g. to local static 1374 // declarations). 1375 llvm::Function *Fn = cast<llvm::Function>(Entry); 1376 setFunctionLinkage(D, Fn); 1377 1378 // FIXME: this is redundant with part of SetFunctionDefinitionAttributes 1379 setGlobalVisibility(Fn, D, /*ForDef*/ true); 1380 1381 CodeGenFunction(*this).GenerateCode(D, Fn); 1382 1383 SetFunctionDefinitionAttributes(D, Fn); 1384 SetLLVMFunctionAttributesForDefinition(D, Fn); 1385 1386 if (const ConstructorAttr *CA = D->getAttr<ConstructorAttr>()) 1387 AddGlobalCtor(Fn, CA->getPriority()); 1388 if (const DestructorAttr *DA = D->getAttr<DestructorAttr>()) 1389 AddGlobalDtor(Fn, DA->getPriority()); 1390 } 1391 1392 void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) { 1393 const ValueDecl *D = cast<ValueDecl>(GD.getDecl()); 1394 const AliasAttr *AA = D->getAttr<AliasAttr>(); 1395 assert(AA && "Not an alias?"); 1396 1397 llvm::StringRef MangledName = getMangledName(GD); 1398 1399 // If there is a definition in the module, then it wins over the alias. 1400 // This is dubious, but allow it to be safe. Just ignore the alias. 1401 llvm::GlobalValue *Entry = GetGlobalValue(MangledName); 1402 if (Entry && !Entry->isDeclaration()) 1403 return; 1404 1405 const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType()); 1406 1407 // Create a reference to the named value. This ensures that it is emitted 1408 // if a deferred decl. 1409 llvm::Constant *Aliasee; 1410 if (isa<llvm::FunctionType>(DeclTy)) 1411 Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GlobalDecl()); 1412 else 1413 Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), 1414 llvm::PointerType::getUnqual(DeclTy), 0); 1415 1416 // Create the new alias itself, but don't set a name yet. 1417 llvm::GlobalValue *GA = 1418 new llvm::GlobalAlias(Aliasee->getType(), 1419 llvm::Function::ExternalLinkage, 1420 "", Aliasee, &getModule()); 1421 1422 if (Entry) { 1423 assert(Entry->isDeclaration()); 1424 1425 // If there is a declaration in the module, then we had an extern followed 1426 // by the alias, as in: 1427 // extern int test6(); 1428 // ... 1429 // int test6() __attribute__((alias("test7"))); 1430 // 1431 // Remove it and replace uses of it with the alias. 1432 GA->takeName(Entry); 1433 1434 Entry->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GA, 1435 Entry->getType())); 1436 Entry->eraseFromParent(); 1437 } else { 1438 GA->setName(MangledName); 1439 } 1440 1441 // Set attributes which are particular to an alias; this is a 1442 // specialization of the attributes which may be set on a global 1443 // variable/function. 1444 if (D->hasAttr<DLLExportAttr>()) { 1445 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 1446 // The dllexport attribute is ignored for undefined symbols. 1447 if (FD->hasBody()) 1448 GA->setLinkage(llvm::Function::DLLExportLinkage); 1449 } else { 1450 GA->setLinkage(llvm::Function::DLLExportLinkage); 1451 } 1452 } else if (D->hasAttr<WeakAttr>() || 1453 D->hasAttr<WeakRefAttr>() || 1454 D->hasAttr<WeakImportAttr>()) { 1455 GA->setLinkage(llvm::Function::WeakAnyLinkage); 1456 } 1457 1458 SetCommonAttributes(D, GA); 1459 } 1460 1461 /// getBuiltinLibFunction - Given a builtin id for a function like 1462 /// "__builtin_fabsf", return a Function* for "fabsf". 1463 llvm::Value *CodeGenModule::getBuiltinLibFunction(const FunctionDecl *FD, 1464 unsigned BuiltinID) { 1465 assert((Context.BuiltinInfo.isLibFunction(BuiltinID) || 1466 Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) && 1467 "isn't a lib fn"); 1468 1469 // Get the name, skip over the __builtin_ prefix (if necessary). 1470 const char *Name = Context.BuiltinInfo.GetName(BuiltinID); 1471 if (Context.BuiltinInfo.isLibFunction(BuiltinID)) 1472 Name += 10; 1473 1474 const llvm::FunctionType *Ty = 1475 cast<llvm::FunctionType>(getTypes().ConvertType(FD->getType())); 1476 1477 return GetOrCreateLLVMFunction(Name, Ty, GlobalDecl(FD)); 1478 } 1479 1480 llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,const llvm::Type **Tys, 1481 unsigned NumTys) { 1482 return llvm::Intrinsic::getDeclaration(&getModule(), 1483 (llvm::Intrinsic::ID)IID, Tys, NumTys); 1484 } 1485 1486 static llvm::StringMapEntry<llvm::Constant*> & 1487 GetConstantCFStringEntry(llvm::StringMap<llvm::Constant*> &Map, 1488 const StringLiteral *Literal, 1489 bool TargetIsLSB, 1490 bool &IsUTF16, 1491 unsigned &StringLength) { 1492 llvm::StringRef String = Literal->getString(); 1493 unsigned NumBytes = String.size(); 1494 1495 // Check for simple case. 1496 if (!Literal->containsNonAsciiOrNull()) { 1497 StringLength = NumBytes; 1498 return Map.GetOrCreateValue(String); 1499 } 1500 1501 // Otherwise, convert the UTF8 literals into a byte string. 1502 llvm::SmallVector<UTF16, 128> ToBuf(NumBytes); 1503 const UTF8 *FromPtr = (UTF8 *)String.data(); 1504 UTF16 *ToPtr = &ToBuf[0]; 1505 1506 (void)ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 1507 &ToPtr, ToPtr + NumBytes, 1508 strictConversion); 1509 1510 // ConvertUTF8toUTF16 returns the length in ToPtr. 1511 StringLength = ToPtr - &ToBuf[0]; 1512 1513 // Render the UTF-16 string into a byte array and convert to the target byte 1514 // order. 1515 // 1516 // FIXME: This isn't something we should need to do here. 1517 llvm::SmallString<128> AsBytes; 1518 AsBytes.reserve(StringLength * 2); 1519 for (unsigned i = 0; i != StringLength; ++i) { 1520 unsigned short Val = ToBuf[i]; 1521 if (TargetIsLSB) { 1522 AsBytes.push_back(Val & 0xFF); 1523 AsBytes.push_back(Val >> 8); 1524 } else { 1525 AsBytes.push_back(Val >> 8); 1526 AsBytes.push_back(Val & 0xFF); 1527 } 1528 } 1529 // Append one extra null character, the second is automatically added by our 1530 // caller. 1531 AsBytes.push_back(0); 1532 1533 IsUTF16 = true; 1534 return Map.GetOrCreateValue(llvm::StringRef(AsBytes.data(), AsBytes.size())); 1535 } 1536 1537 llvm::Constant * 1538 CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) { 1539 unsigned StringLength = 0; 1540 bool isUTF16 = false; 1541 llvm::StringMapEntry<llvm::Constant*> &Entry = 1542 GetConstantCFStringEntry(CFConstantStringMap, Literal, 1543 getTargetData().isLittleEndian(), 1544 isUTF16, StringLength); 1545 1546 if (llvm::Constant *C = Entry.getValue()) 1547 return C; 1548 1549 llvm::Constant *Zero = 1550 llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext)); 1551 llvm::Constant *Zeros[] = { Zero, Zero }; 1552 1553 // If we don't already have it, get __CFConstantStringClassReference. 1554 if (!CFConstantStringClassRef) { 1555 const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy); 1556 Ty = llvm::ArrayType::get(Ty, 0); 1557 llvm::Constant *GV = CreateRuntimeVariable(Ty, 1558 "__CFConstantStringClassReference"); 1559 // Decay array -> ptr 1560 CFConstantStringClassRef = 1561 llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1562 } 1563 1564 QualType CFTy = getContext().getCFConstantStringType(); 1565 1566 const llvm::StructType *STy = 1567 cast<llvm::StructType>(getTypes().ConvertType(CFTy)); 1568 1569 std::vector<llvm::Constant*> Fields(4); 1570 1571 // Class pointer. 1572 Fields[0] = CFConstantStringClassRef; 1573 1574 // Flags. 1575 const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy); 1576 Fields[1] = isUTF16 ? llvm::ConstantInt::get(Ty, 0x07d0) : 1577 llvm::ConstantInt::get(Ty, 0x07C8); 1578 1579 // String pointer. 1580 llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str()); 1581 1582 llvm::GlobalValue::LinkageTypes Linkage; 1583 bool isConstant; 1584 if (isUTF16) { 1585 // FIXME: why do utf strings get "_" labels instead of "L" labels? 1586 Linkage = llvm::GlobalValue::InternalLinkage; 1587 // Note: -fwritable-strings doesn't make unicode CFStrings writable, but 1588 // does make plain ascii ones writable. 1589 isConstant = true; 1590 } else { 1591 Linkage = llvm::GlobalValue::PrivateLinkage; 1592 isConstant = !Features.WritableStrings; 1593 } 1594 1595 llvm::GlobalVariable *GV = 1596 new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C, 1597 ".str"); 1598 GV->setUnnamedAddr(true); 1599 if (isUTF16) { 1600 CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy); 1601 GV->setAlignment(Align.getQuantity()); 1602 } 1603 Fields[2] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1604 1605 // String length. 1606 Ty = getTypes().ConvertType(getContext().LongTy); 1607 Fields[3] = llvm::ConstantInt::get(Ty, StringLength); 1608 1609 // The struct. 1610 C = llvm::ConstantStruct::get(STy, Fields); 1611 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 1612 llvm::GlobalVariable::PrivateLinkage, C, 1613 "_unnamed_cfstring_"); 1614 if (const char *Sect = getContext().Target.getCFStringSection()) 1615 GV->setSection(Sect); 1616 Entry.setValue(GV); 1617 1618 return GV; 1619 } 1620 1621 llvm::Constant * 1622 CodeGenModule::GetAddrOfConstantString(const StringLiteral *Literal) { 1623 unsigned StringLength = 0; 1624 bool isUTF16 = false; 1625 llvm::StringMapEntry<llvm::Constant*> &Entry = 1626 GetConstantCFStringEntry(CFConstantStringMap, Literal, 1627 getTargetData().isLittleEndian(), 1628 isUTF16, StringLength); 1629 1630 if (llvm::Constant *C = Entry.getValue()) 1631 return C; 1632 1633 llvm::Constant *Zero = 1634 llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext)); 1635 llvm::Constant *Zeros[] = { Zero, Zero }; 1636 1637 // If we don't already have it, get _NSConstantStringClassReference. 1638 if (!ConstantStringClassRef) { 1639 std::string StringClass(getLangOptions().ObjCConstantStringClass); 1640 const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy); 1641 Ty = llvm::ArrayType::get(Ty, 0); 1642 llvm::Constant *GV; 1643 if (StringClass.empty()) 1644 GV = CreateRuntimeVariable(Ty, 1645 Features.ObjCNonFragileABI ? 1646 "OBJC_CLASS_$_NSConstantString" : 1647 "_NSConstantStringClassReference"); 1648 else { 1649 std::string str; 1650 if (Features.ObjCNonFragileABI) 1651 str = "OBJC_CLASS_$_" + StringClass; 1652 else 1653 str = "_" + StringClass + "ClassReference"; 1654 GV = CreateRuntimeVariable(Ty, str); 1655 } 1656 // Decay array -> ptr 1657 ConstantStringClassRef = 1658 llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1659 } 1660 1661 QualType NSTy = getContext().getNSConstantStringType(); 1662 1663 const llvm::StructType *STy = 1664 cast<llvm::StructType>(getTypes().ConvertType(NSTy)); 1665 1666 std::vector<llvm::Constant*> Fields(3); 1667 1668 // Class pointer. 1669 Fields[0] = ConstantStringClassRef; 1670 1671 // String pointer. 1672 llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str()); 1673 1674 llvm::GlobalValue::LinkageTypes Linkage; 1675 bool isConstant; 1676 if (isUTF16) { 1677 // FIXME: why do utf strings get "_" labels instead of "L" labels? 1678 Linkage = llvm::GlobalValue::InternalLinkage; 1679 // Note: -fwritable-strings doesn't make unicode NSStrings writable, but 1680 // does make plain ascii ones writable. 1681 isConstant = true; 1682 } else { 1683 Linkage = llvm::GlobalValue::PrivateLinkage; 1684 isConstant = !Features.WritableStrings; 1685 } 1686 1687 llvm::GlobalVariable *GV = 1688 new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C, 1689 ".str"); 1690 GV->setUnnamedAddr(true); 1691 if (isUTF16) { 1692 CharUnits Align = getContext().getTypeAlignInChars(getContext().ShortTy); 1693 GV->setAlignment(Align.getQuantity()); 1694 } 1695 Fields[1] = llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2); 1696 1697 // String length. 1698 const llvm::Type *Ty = getTypes().ConvertType(getContext().UnsignedIntTy); 1699 Fields[2] = llvm::ConstantInt::get(Ty, StringLength); 1700 1701 // The struct. 1702 C = llvm::ConstantStruct::get(STy, Fields); 1703 GV = new llvm::GlobalVariable(getModule(), C->getType(), true, 1704 llvm::GlobalVariable::PrivateLinkage, C, 1705 "_unnamed_nsstring_"); 1706 // FIXME. Fix section. 1707 if (const char *Sect = 1708 Features.ObjCNonFragileABI 1709 ? getContext().Target.getNSStringNonFragileABISection() 1710 : getContext().Target.getNSStringSection()) 1711 GV->setSection(Sect); 1712 Entry.setValue(GV); 1713 1714 return GV; 1715 } 1716 1717 /// GetStringForStringLiteral - Return the appropriate bytes for a 1718 /// string literal, properly padded to match the literal type. 1719 std::string CodeGenModule::GetStringForStringLiteral(const StringLiteral *E) { 1720 const ASTContext &Context = getContext(); 1721 const ConstantArrayType *CAT = 1722 Context.getAsConstantArrayType(E->getType()); 1723 assert(CAT && "String isn't pointer or array!"); 1724 1725 // Resize the string to the right size. 1726 uint64_t RealLen = CAT->getSize().getZExtValue(); 1727 1728 if (E->isWide()) 1729 RealLen *= Context.Target.getWCharWidth() / Context.getCharWidth(); 1730 1731 std::string Str = E->getString().str(); 1732 Str.resize(RealLen, '\0'); 1733 1734 return Str; 1735 } 1736 1737 /// GetAddrOfConstantStringFromLiteral - Return a pointer to a 1738 /// constant array for the given string literal. 1739 llvm::Constant * 1740 CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) { 1741 // FIXME: This can be more efficient. 1742 // FIXME: We shouldn't need to bitcast the constant in the wide string case. 1743 llvm::Constant *C = GetAddrOfConstantString(GetStringForStringLiteral(S)); 1744 if (S->isWide()) { 1745 llvm::Type *DestTy = 1746 llvm::PointerType::getUnqual(getTypes().ConvertType(S->getType())); 1747 C = llvm::ConstantExpr::getBitCast(C, DestTy); 1748 } 1749 return C; 1750 } 1751 1752 /// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant 1753 /// array for the given ObjCEncodeExpr node. 1754 llvm::Constant * 1755 CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) { 1756 std::string Str; 1757 getContext().getObjCEncodingForType(E->getEncodedType(), Str); 1758 1759 return GetAddrOfConstantCString(Str); 1760 } 1761 1762 1763 /// GenerateWritableString -- Creates storage for a string literal. 1764 static llvm::Constant *GenerateStringLiteral(const std::string &str, 1765 bool constant, 1766 CodeGenModule &CGM, 1767 const char *GlobalName) { 1768 // Create Constant for this string literal. Don't add a '\0'. 1769 llvm::Constant *C = 1770 llvm::ConstantArray::get(CGM.getLLVMContext(), str, false); 1771 1772 // Create a global variable for this string 1773 llvm::GlobalVariable *GV = 1774 new llvm::GlobalVariable(CGM.getModule(), C->getType(), constant, 1775 llvm::GlobalValue::PrivateLinkage, 1776 C, GlobalName); 1777 GV->setUnnamedAddr(true); 1778 return GV; 1779 } 1780 1781 /// GetAddrOfConstantString - Returns a pointer to a character array 1782 /// containing the literal. This contents are exactly that of the 1783 /// given string, i.e. it will not be null terminated automatically; 1784 /// see GetAddrOfConstantCString. Note that whether the result is 1785 /// actually a pointer to an LLVM constant depends on 1786 /// Feature.WriteableStrings. 1787 /// 1788 /// The result has pointer to array type. 1789 llvm::Constant *CodeGenModule::GetAddrOfConstantString(const std::string &str, 1790 const char *GlobalName) { 1791 bool IsConstant = !Features.WritableStrings; 1792 1793 // Get the default prefix if a name wasn't specified. 1794 if (!GlobalName) 1795 GlobalName = ".str"; 1796 1797 // Don't share any string literals if strings aren't constant. 1798 if (!IsConstant) 1799 return GenerateStringLiteral(str, false, *this, GlobalName); 1800 1801 llvm::StringMapEntry<llvm::Constant *> &Entry = 1802 ConstantStringMap.GetOrCreateValue(&str[0], &str[str.length()]); 1803 1804 if (Entry.getValue()) 1805 return Entry.getValue(); 1806 1807 // Create a global variable for this. 1808 llvm::Constant *C = GenerateStringLiteral(str, true, *this, GlobalName); 1809 Entry.setValue(C); 1810 return C; 1811 } 1812 1813 /// GetAddrOfConstantCString - Returns a pointer to a character 1814 /// array containing the literal and a terminating '\-' 1815 /// character. The result has pointer to array type. 1816 llvm::Constant *CodeGenModule::GetAddrOfConstantCString(const std::string &str, 1817 const char *GlobalName){ 1818 return GetAddrOfConstantString(str + '\0', GlobalName); 1819 } 1820 1821 /// EmitObjCPropertyImplementations - Emit information for synthesized 1822 /// properties for an implementation. 1823 void CodeGenModule::EmitObjCPropertyImplementations(const 1824 ObjCImplementationDecl *D) { 1825 for (ObjCImplementationDecl::propimpl_iterator 1826 i = D->propimpl_begin(), e = D->propimpl_end(); i != e; ++i) { 1827 ObjCPropertyImplDecl *PID = *i; 1828 1829 // Dynamic is just for type-checking. 1830 if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize) { 1831 ObjCPropertyDecl *PD = PID->getPropertyDecl(); 1832 1833 // Determine which methods need to be implemented, some may have 1834 // been overridden. Note that ::isSynthesized is not the method 1835 // we want, that just indicates if the decl came from a 1836 // property. What we want to know is if the method is defined in 1837 // this implementation. 1838 if (!D->getInstanceMethod(PD->getGetterName())) 1839 CodeGenFunction(*this).GenerateObjCGetter( 1840 const_cast<ObjCImplementationDecl *>(D), PID); 1841 if (!PD->isReadOnly() && 1842 !D->getInstanceMethod(PD->getSetterName())) 1843 CodeGenFunction(*this).GenerateObjCSetter( 1844 const_cast<ObjCImplementationDecl *>(D), PID); 1845 } 1846 } 1847 } 1848 1849 /// EmitObjCIvarInitializations - Emit information for ivar initialization 1850 /// for an implementation. 1851 void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) { 1852 if (!Features.NeXTRuntime || D->getNumIvarInitializers() == 0) 1853 return; 1854 DeclContext* DC = const_cast<DeclContext*>(dyn_cast<DeclContext>(D)); 1855 assert(DC && "EmitObjCIvarInitializations - null DeclContext"); 1856 IdentifierInfo *II = &getContext().Idents.get(".cxx_destruct"); 1857 Selector cxxSelector = getContext().Selectors.getSelector(0, &II); 1858 ObjCMethodDecl *DTORMethod = ObjCMethodDecl::Create(getContext(), 1859 D->getLocation(), 1860 D->getLocation(), cxxSelector, 1861 getContext().VoidTy, 0, 1862 DC, true, false, true, false, 1863 ObjCMethodDecl::Required); 1864 D->addInstanceMethod(DTORMethod); 1865 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, DTORMethod, false); 1866 1867 II = &getContext().Idents.get(".cxx_construct"); 1868 cxxSelector = getContext().Selectors.getSelector(0, &II); 1869 // The constructor returns 'self'. 1870 ObjCMethodDecl *CTORMethod = ObjCMethodDecl::Create(getContext(), 1871 D->getLocation(), 1872 D->getLocation(), cxxSelector, 1873 getContext().getObjCIdType(), 0, 1874 DC, true, false, true, false, 1875 ObjCMethodDecl::Required); 1876 D->addInstanceMethod(CTORMethod); 1877 CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, CTORMethod, true); 1878 1879 1880 } 1881 1882 /// EmitNamespace - Emit all declarations in a namespace. 1883 void CodeGenModule::EmitNamespace(const NamespaceDecl *ND) { 1884 for (RecordDecl::decl_iterator I = ND->decls_begin(), E = ND->decls_end(); 1885 I != E; ++I) 1886 EmitTopLevelDecl(*I); 1887 } 1888 1889 // EmitLinkageSpec - Emit all declarations in a linkage spec. 1890 void CodeGenModule::EmitLinkageSpec(const LinkageSpecDecl *LSD) { 1891 if (LSD->getLanguage() != LinkageSpecDecl::lang_c && 1892 LSD->getLanguage() != LinkageSpecDecl::lang_cxx) { 1893 ErrorUnsupported(LSD, "linkage spec"); 1894 return; 1895 } 1896 1897 for (RecordDecl::decl_iterator I = LSD->decls_begin(), E = LSD->decls_end(); 1898 I != E; ++I) 1899 EmitTopLevelDecl(*I); 1900 } 1901 1902 /// EmitTopLevelDecl - Emit code for a single top level declaration. 1903 void CodeGenModule::EmitTopLevelDecl(Decl *D) { 1904 // If an error has occurred, stop code generation, but continue 1905 // parsing and semantic analysis (to ensure all warnings and errors 1906 // are emitted). 1907 if (Diags.hasErrorOccurred()) 1908 return; 1909 1910 // Ignore dependent declarations. 1911 if (D->getDeclContext() && D->getDeclContext()->isDependentContext()) 1912 return; 1913 1914 switch (D->getKind()) { 1915 case Decl::CXXConversion: 1916 case Decl::CXXMethod: 1917 case Decl::Function: 1918 // Skip function templates 1919 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate()) 1920 return; 1921 1922 EmitGlobal(cast<FunctionDecl>(D)); 1923 break; 1924 1925 case Decl::Var: 1926 EmitGlobal(cast<VarDecl>(D)); 1927 break; 1928 1929 // C++ Decls 1930 case Decl::Namespace: 1931 EmitNamespace(cast<NamespaceDecl>(D)); 1932 break; 1933 // No code generation needed. 1934 case Decl::UsingShadow: 1935 case Decl::Using: 1936 case Decl::UsingDirective: 1937 case Decl::ClassTemplate: 1938 case Decl::FunctionTemplate: 1939 case Decl::NamespaceAlias: 1940 break; 1941 case Decl::CXXConstructor: 1942 // Skip function templates 1943 if (cast<FunctionDecl>(D)->getDescribedFunctionTemplate()) 1944 return; 1945 1946 EmitCXXConstructors(cast<CXXConstructorDecl>(D)); 1947 break; 1948 case Decl::CXXDestructor: 1949 EmitCXXDestructors(cast<CXXDestructorDecl>(D)); 1950 break; 1951 1952 case Decl::StaticAssert: 1953 // Nothing to do. 1954 break; 1955 1956 // Objective-C Decls 1957 1958 // Forward declarations, no (immediate) code generation. 1959 case Decl::ObjCClass: 1960 case Decl::ObjCForwardProtocol: 1961 case Decl::ObjCInterface: 1962 break; 1963 1964 case Decl::ObjCCategory: { 1965 ObjCCategoryDecl *CD = cast<ObjCCategoryDecl>(D); 1966 if (CD->IsClassExtension() && CD->hasSynthBitfield()) 1967 Context.ResetObjCLayout(CD->getClassInterface()); 1968 break; 1969 } 1970 1971 1972 case Decl::ObjCProtocol: 1973 Runtime->GenerateProtocol(cast<ObjCProtocolDecl>(D)); 1974 break; 1975 1976 case Decl::ObjCCategoryImpl: 1977 // Categories have properties but don't support synthesize so we 1978 // can ignore them here. 1979 Runtime->GenerateCategory(cast<ObjCCategoryImplDecl>(D)); 1980 break; 1981 1982 case Decl::ObjCImplementation: { 1983 ObjCImplementationDecl *OMD = cast<ObjCImplementationDecl>(D); 1984 if (Features.ObjCNonFragileABI2 && OMD->hasSynthBitfield()) 1985 Context.ResetObjCLayout(OMD->getClassInterface()); 1986 EmitObjCPropertyImplementations(OMD); 1987 EmitObjCIvarInitializations(OMD); 1988 Runtime->GenerateClass(OMD); 1989 break; 1990 } 1991 case Decl::ObjCMethod: { 1992 ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(D); 1993 // If this is not a prototype, emit the body. 1994 if (OMD->getBody()) 1995 CodeGenFunction(*this).GenerateObjCMethod(OMD); 1996 break; 1997 } 1998 case Decl::ObjCCompatibleAlias: 1999 // compatibility-alias is a directive and has no code gen. 2000 break; 2001 2002 case Decl::LinkageSpec: 2003 EmitLinkageSpec(cast<LinkageSpecDecl>(D)); 2004 break; 2005 2006 case Decl::FileScopeAsm: { 2007 FileScopeAsmDecl *AD = cast<FileScopeAsmDecl>(D); 2008 llvm::StringRef AsmString = AD->getAsmString()->getString(); 2009 2010 const std::string &S = getModule().getModuleInlineAsm(); 2011 if (S.empty()) 2012 getModule().setModuleInlineAsm(AsmString); 2013 else 2014 getModule().setModuleInlineAsm(S + '\n' + AsmString.str()); 2015 break; 2016 } 2017 2018 default: 2019 // Make sure we handled everything we should, every other kind is a 2020 // non-top-level decl. FIXME: Would be nice to have an isTopLevelDeclKind 2021 // function. Need to recode Decl::Kind to do that easily. 2022 assert(isa<TypeDecl>(D) && "Unsupported decl kind"); 2023 } 2024 } 2025 2026 /// Turns the given pointer into a constant. 2027 static llvm::Constant *GetPointerConstant(llvm::LLVMContext &Context, 2028 const void *Ptr) { 2029 uintptr_t PtrInt = reinterpret_cast<uintptr_t>(Ptr); 2030 const llvm::Type *i64 = llvm::Type::getInt64Ty(Context); 2031 return llvm::ConstantInt::get(i64, PtrInt); 2032 } 2033 2034 static void EmitGlobalDeclMetadata(CodeGenModule &CGM, 2035 llvm::NamedMDNode *&GlobalMetadata, 2036 GlobalDecl D, 2037 llvm::GlobalValue *Addr) { 2038 if (!GlobalMetadata) 2039 GlobalMetadata = 2040 CGM.getModule().getOrInsertNamedMetadata("clang.global.decl.ptrs"); 2041 2042 // TODO: should we report variant information for ctors/dtors? 2043 llvm::Value *Ops[] = { 2044 Addr, 2045 GetPointerConstant(CGM.getLLVMContext(), D.getDecl()) 2046 }; 2047 GlobalMetadata->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops, 2)); 2048 } 2049 2050 /// Emits metadata nodes associating all the global values in the 2051 /// current module with the Decls they came from. This is useful for 2052 /// projects using IR gen as a subroutine. 2053 /// 2054 /// Since there's currently no way to associate an MDNode directly 2055 /// with an llvm::GlobalValue, we create a global named metadata 2056 /// with the name 'clang.global.decl.ptrs'. 2057 void CodeGenModule::EmitDeclMetadata() { 2058 llvm::NamedMDNode *GlobalMetadata = 0; 2059 2060 // StaticLocalDeclMap 2061 for (llvm::DenseMap<GlobalDecl,llvm::StringRef>::iterator 2062 I = MangledDeclNames.begin(), E = MangledDeclNames.end(); 2063 I != E; ++I) { 2064 llvm::GlobalValue *Addr = getModule().getNamedValue(I->second); 2065 EmitGlobalDeclMetadata(*this, GlobalMetadata, I->first, Addr); 2066 } 2067 } 2068 2069 /// Emits metadata nodes for all the local variables in the current 2070 /// function. 2071 void CodeGenFunction::EmitDeclMetadata() { 2072 if (LocalDeclMap.empty()) return; 2073 2074 llvm::LLVMContext &Context = getLLVMContext(); 2075 2076 // Find the unique metadata ID for this name. 2077 unsigned DeclPtrKind = Context.getMDKindID("clang.decl.ptr"); 2078 2079 llvm::NamedMDNode *GlobalMetadata = 0; 2080 2081 for (llvm::DenseMap<const Decl*, llvm::Value*>::iterator 2082 I = LocalDeclMap.begin(), E = LocalDeclMap.end(); I != E; ++I) { 2083 const Decl *D = I->first; 2084 llvm::Value *Addr = I->second; 2085 2086 if (llvm::AllocaInst *Alloca = dyn_cast<llvm::AllocaInst>(Addr)) { 2087 llvm::Value *DAddr = GetPointerConstant(getLLVMContext(), D); 2088 Alloca->setMetadata(DeclPtrKind, llvm::MDNode::get(Context, &DAddr, 1)); 2089 } else if (llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(Addr)) { 2090 GlobalDecl GD = GlobalDecl(cast<VarDecl>(D)); 2091 EmitGlobalDeclMetadata(CGM, GlobalMetadata, GD, GV); 2092 } 2093 } 2094 } 2095 2096 ///@name Custom Runtime Function Interfaces 2097 ///@{ 2098 // 2099 // FIXME: These can be eliminated once we can have clients just get the required 2100 // AST nodes from the builtin tables. 2101 2102 llvm::Constant *CodeGenModule::getBlockObjectDispose() { 2103 if (BlockObjectDispose) 2104 return BlockObjectDispose; 2105 2106 // If we saw an explicit decl, use that. 2107 if (BlockObjectDisposeDecl) { 2108 return BlockObjectDispose = GetAddrOfFunction( 2109 BlockObjectDisposeDecl, 2110 getTypes().GetFunctionType(BlockObjectDisposeDecl)); 2111 } 2112 2113 // Otherwise construct the function by hand. 2114 const llvm::FunctionType *FTy; 2115 std::vector<const llvm::Type*> ArgTys; 2116 const llvm::Type *ResultType = llvm::Type::getVoidTy(VMContext); 2117 ArgTys.push_back(PtrToInt8Ty); 2118 ArgTys.push_back(llvm::Type::getInt32Ty(VMContext)); 2119 FTy = llvm::FunctionType::get(ResultType, ArgTys, false); 2120 return BlockObjectDispose = 2121 CreateRuntimeFunction(FTy, "_Block_object_dispose"); 2122 } 2123 2124 llvm::Constant *CodeGenModule::getBlockObjectAssign() { 2125 if (BlockObjectAssign) 2126 return BlockObjectAssign; 2127 2128 // If we saw an explicit decl, use that. 2129 if (BlockObjectAssignDecl) { 2130 return BlockObjectAssign = GetAddrOfFunction( 2131 BlockObjectAssignDecl, 2132 getTypes().GetFunctionType(BlockObjectAssignDecl)); 2133 } 2134 2135 // Otherwise construct the function by hand. 2136 const llvm::FunctionType *FTy; 2137 std::vector<const llvm::Type*> ArgTys; 2138 const llvm::Type *ResultType = llvm::Type::getVoidTy(VMContext); 2139 ArgTys.push_back(PtrToInt8Ty); 2140 ArgTys.push_back(PtrToInt8Ty); 2141 ArgTys.push_back(llvm::Type::getInt32Ty(VMContext)); 2142 FTy = llvm::FunctionType::get(ResultType, ArgTys, false); 2143 return BlockObjectAssign = 2144 CreateRuntimeFunction(FTy, "_Block_object_assign"); 2145 } 2146 2147 llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() { 2148 if (NSConcreteGlobalBlock) 2149 return NSConcreteGlobalBlock; 2150 2151 // If we saw an explicit decl, use that. 2152 if (NSConcreteGlobalBlockDecl) { 2153 return NSConcreteGlobalBlock = GetAddrOfGlobalVar( 2154 NSConcreteGlobalBlockDecl, 2155 getTypes().ConvertType(NSConcreteGlobalBlockDecl->getType())); 2156 } 2157 2158 // Otherwise construct the variable by hand. 2159 return NSConcreteGlobalBlock = CreateRuntimeVariable( 2160 PtrToInt8Ty, "_NSConcreteGlobalBlock"); 2161 } 2162 2163 llvm::Constant *CodeGenModule::getNSConcreteStackBlock() { 2164 if (NSConcreteStackBlock) 2165 return NSConcreteStackBlock; 2166 2167 // If we saw an explicit decl, use that. 2168 if (NSConcreteStackBlockDecl) { 2169 return NSConcreteStackBlock = GetAddrOfGlobalVar( 2170 NSConcreteStackBlockDecl, 2171 getTypes().ConvertType(NSConcreteStackBlockDecl->getType())); 2172 } 2173 2174 // Otherwise construct the variable by hand. 2175 return NSConcreteStackBlock = CreateRuntimeVariable( 2176 PtrToInt8Ty, "_NSConcreteStackBlock"); 2177 } 2178 2179 ///@} 2180