CGDecl.cpp revision 272461
175115Sfenner//===--- CGDecl.cpp - Emit LLVM Code for declarations ---------------------===// 298524Sfenner// 3127668Sbms// The LLVM Compiler Infrastructure 498524Sfenner// 598524Sfenner// This file is distributed under the University of Illinois Open Source 698524Sfenner// License. See LICENSE.TXT for details. 7127668Sbms// 898524Sfenner//===----------------------------------------------------------------------===// 998524Sfenner// 1098524Sfenner// This contains code to emit Decl nodes as LLVM code. 1198524Sfenner// 1298524Sfenner//===----------------------------------------------------------------------===// 1398524Sfenner 1498524Sfenner#include "CodeGenFunction.h" 1598524Sfenner#include "CGDebugInfo.h" 1698524Sfenner#include "CGOpenCLRuntime.h" 17127668Sbms#include "CodeGenModule.h" 1898524Sfenner#include "clang/AST/ASTContext.h" 1998524Sfenner#include "clang/AST/CharUnits.h" 2098524Sfenner#include "clang/AST/Decl.h" 2198524Sfenner#include "clang/AST/DeclObjC.h" 2298524Sfenner#include "clang/Basic/SourceManager.h" 2375115Sfenner#include "clang/Basic/TargetInfo.h" 2475115Sfenner#include "clang/CodeGen/CGFunctionInfo.h" 2575115Sfenner#include "clang/Frontend/CodeGenOptions.h" 2675115Sfenner#include "llvm/IR/DataLayout.h" 2775115Sfenner#include "llvm/IR/GlobalVariable.h" 2875115Sfenner#include "llvm/IR/Intrinsics.h" 2975115Sfenner#include "llvm/IR/Type.h" 3075115Sfennerusing namespace clang; 3175115Sfennerusing namespace CodeGen; 3275115Sfenner 3375115Sfenner 3475115Sfennervoid CodeGenFunction::EmitDecl(const Decl &D) { 3575115Sfenner switch (D.getKind()) { 3675115Sfenner case Decl::TranslationUnit: 3775115Sfenner case Decl::Namespace: 3875115Sfenner case Decl::UnresolvedUsingTypename: 3975115Sfenner case Decl::ClassTemplateSpecialization: 4075115Sfenner case Decl::ClassTemplatePartialSpecialization: 4175115Sfenner case Decl::VarTemplateSpecialization: 42127668Sbms case Decl::VarTemplatePartialSpecialization: 4375115Sfenner case Decl::TemplateTypeParm: 4475115Sfenner case Decl::UnresolvedUsingValue: 4575115Sfenner case Decl::NonTypeTemplateParm: 46127668Sbms case Decl::CXXMethod: 47190207Srpaulo case Decl::CXXConstructor: 4875115Sfenner case Decl::CXXDestructor: 4975115Sfenner case Decl::CXXConversion: 5075115Sfenner case Decl::Field: 5175115Sfenner case Decl::MSProperty: 5275115Sfenner case Decl::IndirectField: 5375115Sfenner case Decl::ObjCIvar: 54127668Sbms case Decl::ObjCAtDefsField: 55127668Sbms case Decl::ParmVar: 5698524Sfenner case Decl::ImplicitParam: 5798524Sfenner case Decl::ClassTemplate: 5875115Sfenner case Decl::VarTemplate: 5975115Sfenner case Decl::FunctionTemplate: 6075115Sfenner case Decl::TypeAliasTemplate: 6175115Sfenner case Decl::TemplateTemplateParm: 6275115Sfenner case Decl::ObjCMethod: 63127668Sbms case Decl::ObjCCategory: 6475115Sfenner case Decl::ObjCProtocol: 6575115Sfenner case Decl::ObjCInterface: 6675115Sfenner case Decl::ObjCCategoryImpl: 6775115Sfenner case Decl::ObjCImplementation: 6875115Sfenner case Decl::ObjCProperty: 6975115Sfenner case Decl::ObjCCompatibleAlias: 7075115Sfenner case Decl::AccessSpec: 7175115Sfenner case Decl::LinkageSpec: 7275115Sfenner case Decl::ObjCPropertyImpl: 7375115Sfenner case Decl::FileScopeAsm: 7475115Sfenner case Decl::Friend: 7575115Sfenner case Decl::FriendTemplate: 7675115Sfenner case Decl::Block: 7775115Sfenner case Decl::Captured: 7875115Sfenner case Decl::ClassScopeFunctionSpecialization: 7975115Sfenner case Decl::UsingShadow: 8075115Sfenner llvm_unreachable("Declaration should not be in declstmts!"); 8175115Sfenner case Decl::Function: // void X(); 8275115Sfenner case Decl::Record: // struct/union/class X; 8375115Sfenner case Decl::Enum: // enum X; 8475115Sfenner case Decl::EnumConstant: // enum ? { X = ? } 8575115Sfenner case Decl::CXXRecord: // struct/union/class X; [C++] 8675115Sfenner case Decl::StaticAssert: // static_assert(X, ""); [C++0x] 87127668Sbms case Decl::Label: // __label__ x; 88127668Sbms case Decl::Import: 89127668Sbms case Decl::OMPThreadPrivate: 90127668Sbms case Decl::Empty: 91127668Sbms // None of these decls require codegen support. 92127668Sbms return; 93127668Sbms 94127668Sbms case Decl::NamespaceAlias: 95127668Sbms if (CGDebugInfo *DI = getDebugInfo()) 96127668Sbms DI->EmitNamespaceAlias(cast<NamespaceAliasDecl>(D)); 97127668Sbms return; 98127668Sbms case Decl::Using: // using X; [C++] 9975115Sfenner if (CGDebugInfo *DI = getDebugInfo()) 10075115Sfenner DI->EmitUsingDecl(cast<UsingDecl>(D)); 10175115Sfenner return; 10275115Sfenner case Decl::UsingDirective: // using namespace X; [C++] 10375115Sfenner if (CGDebugInfo *DI = getDebugInfo()) 10475115Sfenner DI->EmitUsingDirective(cast<UsingDirectiveDecl>(D)); 10575115Sfenner return; 10675115Sfenner case Decl::Var: { 10775115Sfenner const VarDecl &VD = cast<VarDecl>(D); 10875115Sfenner assert(VD.isLocalVarDecl() && 10975115Sfenner "Should not see file-scope variables inside a function!"); 11075115Sfenner return EmitVarDecl(VD); 11175115Sfenner } 11275115Sfenner 11375115Sfenner case Decl::Typedef: // typedef int X; 11475115Sfenner case Decl::TypeAlias: { // using X = int; [C++0x] 11575115Sfenner const TypedefNameDecl &TD = cast<TypedefNameDecl>(D); 11675115Sfenner QualType Ty = TD.getUnderlyingType(); 11775115Sfenner 11875115Sfenner if (Ty->isVariablyModifiedType()) 11975115Sfenner EmitVariablyModifiedType(Ty); 12075115Sfenner } 12175115Sfenner } 12275115Sfenner} 12375115Sfenner 12475115Sfenner/// EmitVarDecl - This method handles emission of any variable declaration 12575115Sfenner/// inside a function, including static vars etc. 12675115Sfennervoid CodeGenFunction::EmitVarDecl(const VarDecl &D) { 12775115Sfenner if (D.isStaticLocal()) { 12875115Sfenner llvm::GlobalValue::LinkageTypes Linkage = 12975115Sfenner llvm::GlobalValue::InternalLinkage; 13075115Sfenner 13175115Sfenner // If the variable is externally visible, it must have weak linkage so it 13275115Sfenner // can be uniqued. 13375115Sfenner if (D.isExternallyVisible()) { 13475115Sfenner Linkage = llvm::GlobalValue::LinkOnceODRLinkage; 13575115Sfenner 13675115Sfenner // FIXME: We need to force the emission/use of a guard variable for 13775115Sfenner // some variables even if we can constant-evaluate them because 13875115Sfenner // we can't guarantee every translation unit will constant-evaluate them. 13975115Sfenner } 14075115Sfenner 141127668Sbms return EmitStaticVarDecl(D, Linkage); 14275115Sfenner } 14375115Sfenner 14475115Sfenner if (D.hasExternalStorage()) 14575115Sfenner // Don't emit it now, allow it to be emitted lazily on its first use. 14675115Sfenner return; 14775115Sfenner 14875115Sfenner if (D.getStorageClass() == SC_OpenCLWorkGroupLocal) 14975115Sfenner return CGM.getOpenCLRuntime().EmitWorkGroupLocalVarDecl(*this, D); 15075115Sfenner 15175115Sfenner assert(D.hasLocalStorage()); 15275115Sfenner return EmitAutoVarDecl(D); 15398524Sfenner} 15475115Sfenner 15575115Sfennerstatic std::string GetStaticDeclName(CodeGenFunction &CGF, const VarDecl &D, 15675115Sfenner const char *Separator) { 15775115Sfenner CodeGenModule &CGM = CGF.CGM; 15875115Sfenner if (CGF.getLangOpts().CPlusPlus) { 15975115Sfenner StringRef Name = CGM.getMangledName(&D); 160127668Sbms return Name.str(); 16175115Sfenner } 16275115Sfenner 163127668Sbms std::string ContextName; 16475115Sfenner if (!CGF.CurFuncDecl) { 16575115Sfenner // Better be in a block declared in global scope. 16675115Sfenner const NamedDecl *ND = cast<NamedDecl>(&D); 16775115Sfenner const DeclContext *DC = ND->getDeclContext(); 168127668Sbms if (const BlockDecl *BD = dyn_cast<BlockDecl>(DC)) { 16975115Sfenner MangleBuffer Name; 17075115Sfenner CGM.getBlockMangledName(GlobalDecl(), Name, BD); 17175115Sfenner ContextName = Name.getString(); 17275115Sfenner } 173127668Sbms else 17475115Sfenner llvm_unreachable("Unknown context for block static var decl"); 17575115Sfenner } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CGF.CurFuncDecl)) { 17675115Sfenner StringRef Name = CGM.getMangledName(FD); 17775115Sfenner ContextName = Name.str(); 17875115Sfenner } else if (isa<ObjCMethodDecl>(CGF.CurFuncDecl)) 17975115Sfenner ContextName = CGF.CurFn->getName(); 18075115Sfenner else 18175115Sfenner llvm_unreachable("Unknown context for static var decl"); 18275115Sfenner 183127668Sbms return ContextName + Separator + D.getNameAsString(); 18475115Sfenner} 18575115Sfenner 18675115Sfennerllvm::GlobalVariable * 18775115SfennerCodeGenFunction::CreateStaticVarDecl(const VarDecl &D, 18875115Sfenner const char *Separator, 18975115Sfenner llvm::GlobalValue::LinkageTypes Linkage) { 190127668Sbms QualType Ty = D.getType(); 19175115Sfenner assert(Ty->isConstantSizeType() && "VLAs can't be static"); 19275115Sfenner 19375115Sfenner // Use the label if the variable is renamed with the asm-label extension. 19475115Sfenner std::string Name; 19575115Sfenner if (D.hasAttr<AsmLabelAttr>()) 19675115Sfenner Name = CGM.getMangledName(&D); 19775115Sfenner else 19875115Sfenner Name = GetStaticDeclName(*this, D, Separator); 19975115Sfenner 20075115Sfenner llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(Ty); 20175115Sfenner unsigned AddrSpace = 20275115Sfenner CGM.GetGlobalVarAddressSpace(&D, CGM.getContext().getTargetAddressSpace(Ty)); 20375115Sfenner llvm::GlobalVariable *GV = 20475115Sfenner new llvm::GlobalVariable(CGM.getModule(), LTy, 20575115Sfenner Ty.isConstant(getContext()), Linkage, 20675115Sfenner CGM.EmitNullConstant(D.getType()), Name, 0, 20775115Sfenner llvm::GlobalVariable::NotThreadLocal, 20875115Sfenner AddrSpace); 20975115Sfenner GV->setAlignment(getContext().getDeclAlign(&D).getQuantity()); 21075115Sfenner CGM.setGlobalVisibility(GV, &D); 21175115Sfenner 21275115Sfenner if (D.getTLSKind()) 21375115Sfenner CGM.setTLSMode(GV, D); 21475115Sfenner 21575115Sfenner return GV; 21675115Sfenner} 21775115Sfenner 21875115Sfenner/// hasNontrivialDestruction - Determine whether a type's destruction is 21975115Sfenner/// non-trivial. If so, and the variable uses static initialization, we must 22075115Sfenner/// register its destructor to run on exit. 22175115Sfennerstatic bool hasNontrivialDestruction(QualType T) { 22275115Sfenner CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl(); 22375115Sfenner return RD && !RD->hasTrivialDestructor(); 22475115Sfenner} 22575115Sfenner 22675115Sfenner/// AddInitializerToStaticVarDecl - Add the initializer for 'D' to the 22775115Sfenner/// global variable that has already been created for it. If the initializer 22875115Sfenner/// has a different type than GV does, this may free GV and return a different 22975115Sfenner/// one. Otherwise it just returns GV. 23075115Sfennerllvm::GlobalVariable * 23175115SfennerCodeGenFunction::AddInitializerToStaticVarDecl(const VarDecl &D, 23275115Sfenner llvm::GlobalVariable *GV) { 23375115Sfenner llvm::Constant *Init = CGM.EmitConstantInit(D, this); 23475115Sfenner 23575115Sfenner // If constant emission failed, then this should be a C++ static 23675115Sfenner // initializer. 23775115Sfenner if (!Init) { 238127668Sbms if (!getLangOpts().CPlusPlus) 23975115Sfenner CGM.ErrorUnsupported(D.getInit(), "constant l-value expression"); 24075115Sfenner else if (Builder.GetInsertBlock()) { 24175115Sfenner // Since we have a static initializer, this global variable can't 24275115Sfenner // be constant. 24375115Sfenner GV->setConstant(false); 24475115Sfenner 24575115Sfenner EmitCXXGuardedInit(D, GV, /*PerformInit*/true); 24675115Sfenner } 24775115Sfenner return GV; 24875115Sfenner } 24975115Sfenner 25075115Sfenner // The initializer may differ in type from the global. Rewrite 25175115Sfenner // the global to match the initializer. (We have to do this 25275115Sfenner // because some types, like unions, can't be completely represented 25375115Sfenner // in the LLVM type system.) 25475115Sfenner if (GV->getType()->getElementType() != Init->getType()) { 25575115Sfenner llvm::GlobalVariable *OldGV = GV; 25675115Sfenner 25775115Sfenner GV = new llvm::GlobalVariable(CGM.getModule(), Init->getType(), 25875115Sfenner OldGV->isConstant(), 25975115Sfenner OldGV->getLinkage(), Init, "", 26075115Sfenner /*InsertBefore*/ OldGV, 26175115Sfenner OldGV->getThreadLocalMode(), 26275115Sfenner CGM.getContext().getTargetAddressSpace(D.getType())); 26375115Sfenner GV->setVisibility(OldGV->getVisibility()); 26475115Sfenner 26575115Sfenner // Steal the name of the old global 26675115Sfenner GV->takeName(OldGV); 26775115Sfenner 26875115Sfenner // Replace all uses of the old global with the new global 26975115Sfenner llvm::Constant *NewPtrForOldDecl = 27075115Sfenner llvm::ConstantExpr::getBitCast(GV, OldGV->getType()); 27175115Sfenner OldGV->replaceAllUsesWith(NewPtrForOldDecl); 27275115Sfenner 27375115Sfenner // Erase the old global, since it is no longer used. 27475115Sfenner OldGV->eraseFromParent(); 27575115Sfenner } 27675115Sfenner 27775115Sfenner GV->setConstant(CGM.isTypeConstant(D.getType(), true)); 27875115Sfenner GV->setInitializer(Init); 27975115Sfenner 28075115Sfenner if (hasNontrivialDestruction(D.getType())) { 28175115Sfenner // We have a constant initializer, but a nontrivial destructor. We still 28275115Sfenner // need to perform a guarded "initialization" in order to register the 28375115Sfenner // destructor. 28475115Sfenner EmitCXXGuardedInit(D, GV, /*PerformInit*/false); 28575115Sfenner } 28675115Sfenner 28775115Sfenner return GV; 28875115Sfenner} 28975115Sfenner 29075115Sfennervoid CodeGenFunction::EmitStaticVarDecl(const VarDecl &D, 29175115Sfenner llvm::GlobalValue::LinkageTypes Linkage) { 29275115Sfenner llvm::Value *&DMEntry = LocalDeclMap[&D]; 29375115Sfenner assert(DMEntry == 0 && "Decl already exists in localdeclmap!"); 29475115Sfenner 29575115Sfenner // Check to see if we already have a global variable for this 29675115Sfenner // declaration. This can happen when double-emitting function 29775115Sfenner // bodies, e.g. with complete and base constructors. 29875115Sfenner llvm::Constant *addr = 29975115Sfenner CGM.getStaticLocalDeclAddress(&D); 30075115Sfenner 30175115Sfenner llvm::GlobalVariable *var; 30275115Sfenner if (addr) { 303127668Sbms var = cast<llvm::GlobalVariable>(addr->stripPointerCasts()); 30475115Sfenner } else { 30575115Sfenner addr = var = CreateStaticVarDecl(D, ".", Linkage); 30675115Sfenner } 30775115Sfenner 30875115Sfenner // Store into LocalDeclMap before generating initializer to handle 30975115Sfenner // circular references. 31075115Sfenner DMEntry = addr; 31175115Sfenner CGM.setStaticLocalDeclAddress(&D, addr); 31275115Sfenner 31375115Sfenner // We can't have a VLA here, but we can have a pointer to a VLA, 31475115Sfenner // even though that doesn't really make any sense. 31575115Sfenner // Make sure to evaluate VLA bounds now so that we have them for later. 31675115Sfenner if (D.getType()->isVariablyModifiedType()) 31775115Sfenner EmitVariablyModifiedType(D.getType()); 31875115Sfenner 31975115Sfenner // Save the type in case adding the initializer forces a type change. 32075115Sfenner llvm::Type *expectedType = addr->getType(); 32175115Sfenner 32275115Sfenner // If this value has an initializer, emit it. 32375115Sfenner if (D.getInit()) 32475115Sfenner var = AddInitializerToStaticVarDecl(D, var); 32575115Sfenner 32675115Sfenner var->setAlignment(getContext().getDeclAlign(&D).getQuantity()); 32775115Sfenner 32875115Sfenner if (D.hasAttr<AnnotateAttr>()) 32975115Sfenner CGM.AddGlobalAnnotations(&D, var); 33075115Sfenner 33175115Sfenner if (const SectionAttr *SA = D.getAttr<SectionAttr>()) 33275115Sfenner var->setSection(SA->getName()); 33375115Sfenner 334127668Sbms if (D.hasAttr<UsedAttr>()) 335127668Sbms CGM.AddUsedGlobal(var); 336127668Sbms 33775115Sfenner // We may have to cast the constant because of the initializer 33875115Sfenner // mismatch above. 33975115Sfenner // 34075115Sfenner // FIXME: It is really dangerous to store this in the map; if anyone 34175115Sfenner // RAUW's the GV uses of this constant will be invalid. 34275115Sfenner llvm::Constant *castedAddr = llvm::ConstantExpr::getBitCast(var, expectedType); 343127668Sbms DMEntry = castedAddr; 344127668Sbms CGM.setStaticLocalDeclAddress(&D, castedAddr); 345127668Sbms 346127668Sbms // Emit global variable debug descriptor for static vars. 347127668Sbms CGDebugInfo *DI = getDebugInfo(); 348127668Sbms if (DI && 349127668Sbms CGM.getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo) { 350127668Sbms DI->setLocation(D.getLocation()); 351127668Sbms DI->EmitGlobalVariable(var, &D); 352127668Sbms } 353127668Sbms} 354127668Sbms 355127668Sbmsnamespace { 356127668Sbms struct DestroyObject : EHScopeStack::Cleanup { 357127668Sbms DestroyObject(llvm::Value *addr, QualType type, 358127668Sbms CodeGenFunction::Destroyer *destroyer, 359127668Sbms bool useEHCleanupForArray) 360127668Sbms : addr(addr), type(type), destroyer(destroyer), 361127668Sbms useEHCleanupForArray(useEHCleanupForArray) {} 362127668Sbms 363127668Sbms llvm::Value *addr; 364127668Sbms QualType type; 365127668Sbms CodeGenFunction::Destroyer *destroyer; 366127668Sbms bool useEHCleanupForArray; 367127668Sbms 368127668Sbms void Emit(CodeGenFunction &CGF, Flags flags) { 369127668Sbms // Don't use an EH cleanup recursively from an EH cleanup. 370127668Sbms bool useEHCleanupForArray = 371127668Sbms flags.isForNormalCleanup() && this->useEHCleanupForArray; 372127668Sbms 373127668Sbms CGF.emitDestroy(addr, type, destroyer, useEHCleanupForArray); 374127668Sbms } 375127668Sbms }; 376127668Sbms 377127668Sbms struct DestroyNRVOVariable : EHScopeStack::Cleanup { 378127668Sbms DestroyNRVOVariable(llvm::Value *addr, 379127668Sbms const CXXDestructorDecl *Dtor, 380127668Sbms llvm::Value *NRVOFlag) 381127668Sbms : Dtor(Dtor), NRVOFlag(NRVOFlag), Loc(addr) {} 382127668Sbms 383127668Sbms const CXXDestructorDecl *Dtor; 384127668Sbms llvm::Value *NRVOFlag; 385127668Sbms llvm::Value *Loc; 386127668Sbms 387127668Sbms void Emit(CodeGenFunction &CGF, Flags flags) { 388127668Sbms // Along the exceptions path we always execute the dtor. 389127668Sbms bool NRVO = flags.isForNormalCleanup() && NRVOFlag; 390127668Sbms 391127668Sbms llvm::BasicBlock *SkipDtorBB = 0; 392127668Sbms if (NRVO) { 393127668Sbms // If we exited via NRVO, we skip the destructor call. 394127668Sbms llvm::BasicBlock *RunDtorBB = CGF.createBasicBlock("nrvo.unused"); 395127668Sbms SkipDtorBB = CGF.createBasicBlock("nrvo.skipdtor"); 396127668Sbms llvm::Value *DidNRVO = CGF.Builder.CreateLoad(NRVOFlag, "nrvo.val"); 397127668Sbms CGF.Builder.CreateCondBr(DidNRVO, SkipDtorBB, RunDtorBB); 398127668Sbms CGF.EmitBlock(RunDtorBB); 399127668Sbms } 400127668Sbms 401127668Sbms CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, 402127668Sbms /*ForVirtualBase=*/false, 403127668Sbms /*Delegating=*/false, 404127668Sbms Loc); 405127668Sbms 406127668Sbms if (NRVO) CGF.EmitBlock(SkipDtorBB); 407127668Sbms } 408127668Sbms }; 409127668Sbms 410127668Sbms struct CallStackRestore : EHScopeStack::Cleanup { 411127668Sbms llvm::Value *Stack; 412127668Sbms CallStackRestore(llvm::Value *Stack) : Stack(Stack) {} 413127668Sbms void Emit(CodeGenFunction &CGF, Flags flags) { 414127668Sbms llvm::Value *V = CGF.Builder.CreateLoad(Stack); 415127668Sbms llvm::Value *F = CGF.CGM.getIntrinsic(llvm::Intrinsic::stackrestore); 416127668Sbms CGF.Builder.CreateCall(F, V); 417127668Sbms } 418127668Sbms }; 419127668Sbms 420127668Sbms struct ExtendGCLifetime : EHScopeStack::Cleanup { 421127668Sbms const VarDecl &Var; 422127668Sbms ExtendGCLifetime(const VarDecl *var) : Var(*var) {} 423127668Sbms 424127668Sbms void Emit(CodeGenFunction &CGF, Flags flags) { 425127668Sbms // Compute the address of the local variable, in case it's a 426127668Sbms // byref or something. 427127668Sbms DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false, 428127668Sbms Var.getType(), VK_LValue, SourceLocation()); 429127668Sbms llvm::Value *value = CGF.EmitLoadOfScalar(CGF.EmitDeclRefLValue(&DRE), 430127668Sbms SourceLocation()); 431127668Sbms CGF.EmitExtendGCLifetime(value); 432127668Sbms } 433127668Sbms }; 434127668Sbms 435127668Sbms struct CallCleanupFunction : EHScopeStack::Cleanup { 436127668Sbms llvm::Constant *CleanupFn; 437127668Sbms const CGFunctionInfo &FnInfo; 43875115Sfenner const VarDecl &Var; 43975115Sfenner 44075115Sfenner CallCleanupFunction(llvm::Constant *CleanupFn, const CGFunctionInfo *Info, 44175115Sfenner const VarDecl *Var) 44275115Sfenner : CleanupFn(CleanupFn), FnInfo(*Info), Var(*Var) {} 44375115Sfenner 44475115Sfenner void Emit(CodeGenFunction &CGF, Flags flags) { 44575115Sfenner DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false, 44675115Sfenner Var.getType(), VK_LValue, SourceLocation()); 44775115Sfenner // Compute the address of the local variable, in case it's a byref 44875115Sfenner // or something. 44975115Sfenner llvm::Value *Addr = CGF.EmitDeclRefLValue(&DRE).getAddress(); 45075115Sfenner 451127668Sbms // In some cases, the type of the function argument will be different from 45275115Sfenner // the type of the pointer. An example of this is 453127668Sbms // void f(void* arg); 45475115Sfenner // __attribute__((cleanup(f))) void *g; 45575115Sfenner // 45675115Sfenner // To fix this we insert a bitcast here. 457162017Ssam QualType ArgTy = FnInfo.arg_begin()->type; 458162017Ssam llvm::Value *Arg = 459162017Ssam CGF.Builder.CreateBitCast(Addr, CGF.ConvertType(ArgTy)); 460162017Ssam 461162017Ssam CallArgList Args; 46275115Sfenner Args.add(RValue::get(Arg), 463127668Sbms CGF.getContext().getPointerType(Var.getType())); 46475115Sfenner CGF.EmitCall(FnInfo, CleanupFn, ReturnValueSlot(), Args); 465162017Ssam } 466127668Sbms }; 46775115Sfenner 46875115Sfenner /// A cleanup to call @llvm.lifetime.end. 46975115Sfenner class CallLifetimeEnd : public EHScopeStack::Cleanup { 47075115Sfenner llvm::Value *Addr; 47175115Sfenner llvm::Value *Size; 47275115Sfenner public: 47375115Sfenner CallLifetimeEnd(llvm::Value *addr, llvm::Value *size) 47475115Sfenner : Addr(addr), Size(size) {} 47575115Sfenner 47675115Sfenner void Emit(CodeGenFunction &CGF, Flags flags) { 47775115Sfenner llvm::Value *castAddr = CGF.Builder.CreateBitCast(Addr, CGF.Int8PtrTy); 478162017Ssam CGF.Builder.CreateCall2(CGF.CGM.getLLVMLifetimeEndFn(), 479162017Ssam Size, castAddr) 480162017Ssam ->setDoesNotThrow(); 481162017Ssam } 482162017Ssam }; 483127668Sbms} 48475115Sfenner 48575115Sfenner/// EmitAutoVarWithLifetime - Does the setup required for an automatic 48675115Sfenner/// variable with lifetime. 48775115Sfennerstatic void EmitAutoVarWithLifetime(CodeGenFunction &CGF, const VarDecl &var, 48875115Sfenner llvm::Value *addr, 48975115Sfenner Qualifiers::ObjCLifetime lifetime) { 490124488Sfenner switch (lifetime) { 49175115Sfenner case Qualifiers::OCL_None: 49275115Sfenner llvm_unreachable("present but none"); 49375115Sfenner 494127668Sbms case Qualifiers::OCL_ExplicitNone: 49575115Sfenner // nothing to do 496162017Ssam break; 497127668Sbms 49875115Sfenner case Qualifiers::OCL_Strong: { 499127668Sbms CodeGenFunction::Destroyer *destroyer = 500127668Sbms (var.hasAttr<ObjCPreciseLifetimeAttr>() 501127668Sbms ? CodeGenFunction::destroyARCStrongPrecise 50275115Sfenner : CodeGenFunction::destroyARCStrongImprecise); 503127668Sbms 504127668Sbms CleanupKind cleanupKind = CGF.getARCCleanupKind(); 505127668Sbms CGF.pushDestroy(cleanupKind, addr, var.getType(), destroyer, 506127668Sbms cleanupKind & EHCleanup); 507127668Sbms break; 508127668Sbms } 509127668Sbms case Qualifiers::OCL_Autoreleasing: 510127668Sbms // nothing to do 511162017Ssam break; 512162017Ssam 513162017Ssam case Qualifiers::OCL_Weak: 514127668Sbms // __weak objects always get EH cleanups; otherwise, exceptions 515127668Sbms // could cause really nasty crashes instead of mere leaks. 516127668Sbms CGF.pushDestroy(NormalAndEHCleanup, addr, var.getType(), 517127668Sbms CodeGenFunction::destroyARCWeak, 518127668Sbms /*useEHCleanup*/ true); 519127668Sbms break; 520127668Sbms } 521127668Sbms} 522127668Sbms 523162017Ssamstatic bool isAccessedBy(const VarDecl &var, const Stmt *s) { 524127668Sbms if (const Expr *e = dyn_cast<Expr>(s)) { 525127668Sbms // Skip the most common kinds of expressions that make 526127668Sbms // hierarchy-walking expensive. 527127668Sbms s = e = e->IgnoreParenCasts(); 528162017Ssam 529162017Ssam if (const DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) 530162017Ssam return (ref->getDecl() == &var); 531162017Ssam if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) { 532162017Ssam const BlockDecl *block = be->getBlockDecl(); 533162017Ssam for (BlockDecl::capture_const_iterator i = block->capture_begin(), 534162017Ssam e = block->capture_end(); i != e; ++i) { 535162017Ssam if (i->getVariable() == &var) 536162017Ssam return true; 537162017Ssam } 538162017Ssam } 539162017Ssam } 540162017Ssam 541162017Ssam for (Stmt::const_child_range children = s->children(); children; ++children) 542127668Sbms // children might be null; as in missing decl or conditional of an if-stmt. 543162017Ssam if ((*children) && isAccessedBy(var, *children)) 544162017Ssam return true; 545162017Ssam 546127668Sbms return false; 547127668Sbms} 548127668Sbms 549127668Sbmsstatic bool isAccessedBy(const ValueDecl *decl, const Expr *e) { 550127668Sbms if (!decl) return false; 551127668Sbms if (!isa<VarDecl>(decl)) return false; 552127668Sbms const VarDecl *var = cast<VarDecl>(decl); 553127668Sbms return isAccessedBy(*var, e); 554162017Ssam} 555162017Ssam 556162017Ssamstatic void drillIntoBlockVariable(CodeGenFunction &CGF, 557162017Ssam LValue &lvalue, 558127668Sbms const VarDecl *var) { 559127668Sbms lvalue.setAddress(CGF.BuildBlockByrefAddress(lvalue.getAddress(), var)); 560127668Sbms} 561127668Sbms 56275115Sfennervoid CodeGenFunction::EmitScalarInit(const Expr *init, 56375115Sfenner const ValueDecl *D, 56475115Sfenner LValue lvalue, 56575115Sfenner bool capturedByInit) { 56675115Sfenner Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime(); 56775115Sfenner if (!lifetime) { 56875115Sfenner llvm::Value *value = EmitScalarExpr(init); 56975115Sfenner if (capturedByInit) 57075115Sfenner drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D)); 57175115Sfenner EmitStoreThroughLValue(RValue::get(value), lvalue, true); 57275115Sfenner return; 57375115Sfenner } 574127668Sbms 57575115Sfenner // If we're emitting a value with lifetime, we have to do the 57675115Sfenner // initialization *before* we leave the cleanup scopes. 577127668Sbms if (const ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(init)) { 57875115Sfenner enterFullExpression(ewc); 57975115Sfenner init = ewc->getSubExpr(); 58075115Sfenner } 58175115Sfenner CodeGenFunction::RunCleanupsScope Scope(*this); 58275115Sfenner 583127668Sbms // We have to maintain the illusion that the variable is 58475115Sfenner // zero-initialized. If the variable might be accessed in its 58575115Sfenner // initializer, zero-initialize before running the initializer, then 58675115Sfenner // actually perform the initialization with an assign. 58775115Sfenner bool accessedByInit = false; 588127668Sbms if (lifetime != Qualifiers::OCL_ExplicitNone) 58975115Sfenner accessedByInit = (capturedByInit || isAccessedBy(D, init)); 59075115Sfenner if (accessedByInit) { 59175115Sfenner LValue tempLV = lvalue; 592127668Sbms // Drill down to the __block object if necessary. 59375115Sfenner if (capturedByInit) { 594127668Sbms // We can use a simple GEP for this because it can't have been 59575115Sfenner // moved yet. 59675115Sfenner tempLV.setAddress(Builder.CreateStructGEP(tempLV.getAddress(), 59775115Sfenner getByRefValueLLVMField(cast<VarDecl>(D)))); 59875115Sfenner } 59975115Sfenner 60075115Sfenner llvm::PointerType *ty 60175115Sfenner = cast<llvm::PointerType>(tempLV.getAddress()->getType()); 602127668Sbms ty = cast<llvm::PointerType>(ty->getElementType()); 603111726Sfenner 604111726Sfenner llvm::Value *zero = llvm::ConstantPointerNull::get(ty); 605127668Sbms 60675115Sfenner // If __weak, we want to use a barrier under certain conditions. 607127668Sbms if (lifetime == Qualifiers::OCL_Weak) 60875115Sfenner EmitARCInitWeak(tempLV.getAddress(), zero); 60975115Sfenner 61075115Sfenner // Otherwise just do a simple store. 61175115Sfenner else 61275115Sfenner EmitStoreOfScalar(zero, tempLV, /* isInitialization */ true); 61375115Sfenner } 61475115Sfenner 615127668Sbms // Emit the initializer. 61675115Sfenner llvm::Value *value = 0; 617127668Sbms 61875115Sfenner switch (lifetime) { 61975115Sfenner case Qualifiers::OCL_None: 62075115Sfenner llvm_unreachable("present but none"); 62175115Sfenner 62275115Sfenner case Qualifiers::OCL_ExplicitNone: 62375115Sfenner // nothing to do 62475115Sfenner value = EmitScalarExpr(init); 62575115Sfenner break; 62675115Sfenner 627127668Sbms case Qualifiers::OCL_Strong: { 62875115Sfenner value = EmitARCRetainScalarExpr(init); 62975115Sfenner break; 63075115Sfenner } 631127668Sbms 63275115Sfenner case Qualifiers::OCL_Weak: { 63375115Sfenner // No way to optimize a producing initializer into this. It's not 634127668Sbms // worth optimizing for, because the value will immediately 635127668Sbms // disappear in the common case. 63675115Sfenner value = EmitScalarExpr(init); 63775115Sfenner 63875115Sfenner if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D)); 63975115Sfenner if (accessedByInit) 64075115Sfenner EmitARCStoreWeak(lvalue.getAddress(), value, /*ignored*/ true); 641127668Sbms else 642127668Sbms EmitARCInitWeak(lvalue.getAddress(), value); 64375115Sfenner return; 644127668Sbms } 64575115Sfenner 646127668Sbms case Qualifiers::OCL_Autoreleasing: 64775115Sfenner value = EmitARCRetainAutoreleaseScalarExpr(init); 648127668Sbms break; 649127668Sbms } 65075115Sfenner 651127668Sbms if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D)); 65275115Sfenner 65375115Sfenner // If the variable might have been accessed by its initializer, we 65475115Sfenner // might have to initialize with a barrier. We have to do this for 65575115Sfenner // both __weak and __strong, but __weak got filtered out above. 65675115Sfenner if (accessedByInit && lifetime == Qualifiers::OCL_Strong) { 65775115Sfenner llvm::Value *oldValue = EmitLoadOfScalar(lvalue, init->getExprLoc()); 658127668Sbms EmitStoreOfScalar(value, lvalue, /* isInitialization */ true); 65975115Sfenner EmitARCRelease(oldValue, ARCImpreciseLifetime); 660127668Sbms return; 66175115Sfenner } 66275115Sfenner 66375115Sfenner EmitStoreOfScalar(value, lvalue, /* isInitialization */ true); 664127668Sbms} 66575115Sfenner 666127668Sbms/// EmitScalarInit - Initialize the given lvalue with the given object. 66775115Sfennervoid CodeGenFunction::EmitScalarInit(llvm::Value *init, LValue lvalue) { 668127668Sbms Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime(); 66975115Sfenner if (!lifetime) 67075115Sfenner return EmitStoreThroughLValue(RValue::get(init), lvalue, true); 67175115Sfenner 672127668Sbms switch (lifetime) { 67375115Sfenner case Qualifiers::OCL_None: 674162017Ssam llvm_unreachable("present but none"); 67575115Sfenner 67675115Sfenner case Qualifiers::OCL_ExplicitNone: 67775115Sfenner // nothing to do 67875115Sfenner break; 67975115Sfenner 68075115Sfenner case Qualifiers::OCL_Strong: 68175115Sfenner init = EmitARCRetain(lvalue.getType(), init); 68275115Sfenner break; 68375115Sfenner 68475115Sfenner case Qualifiers::OCL_Weak: 68575115Sfenner // Initialize and then skip the primitive store. 68675115Sfenner EmitARCInitWeak(lvalue.getAddress(), init); 68775115Sfenner return; 68875115Sfenner 68975115Sfenner case Qualifiers::OCL_Autoreleasing: 690127668Sbms init = EmitARCRetainAutorelease(lvalue.getType(), init); 69175115Sfenner break; 69275115Sfenner } 69375115Sfenner 69475115Sfenner EmitStoreOfScalar(init, lvalue, /* isInitialization */ true); 695127668Sbms} 69675115Sfenner 69775115Sfenner/// canEmitInitWithFewStoresAfterMemset - Decide whether we can emit the 69875115Sfenner/// non-zero parts of the specified initializer with equal or fewer than 69975115Sfenner/// NumStores scalar stores. 70075115Sfennerstatic bool canEmitInitWithFewStoresAfterMemset(llvm::Constant *Init, 701127668Sbms unsigned &NumStores) { 70275115Sfenner // Zero and Undef never requires any extra stores. 70375115Sfenner if (isa<llvm::ConstantAggregateZero>(Init) || 704127668Sbms isa<llvm::ConstantPointerNull>(Init) || 70575115Sfenner isa<llvm::UndefValue>(Init)) 706127668Sbms return true; 70775115Sfenner if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) || 708127668Sbms isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) || 70975115Sfenner isa<llvm::ConstantExpr>(Init)) 710127668Sbms return Init->isNullValue() || NumStores--; 71175115Sfenner 71275115Sfenner // See if we can emit each element. 713127668Sbms if (isa<llvm::ConstantArray>(Init) || isa<llvm::ConstantStruct>(Init)) { 71475115Sfenner for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) { 715127668Sbms llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i)); 71675115Sfenner if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores)) 717162017Ssam return false; 71875115Sfenner } 71975115Sfenner return true; 72075115Sfenner } 72175115Sfenner 72275115Sfenner if (llvm::ConstantDataSequential *CDS = 72375115Sfenner dyn_cast<llvm::ConstantDataSequential>(Init)) { 72475115Sfenner for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) { 72575115Sfenner llvm::Constant *Elt = CDS->getElementAsConstant(i); 72675115Sfenner if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores)) 72775115Sfenner return false; 72875115Sfenner } 729127668Sbms return true; 73075115Sfenner } 73175115Sfenner 73275115Sfenner // Anything else is hard and scary. 73375115Sfenner return false; 73475115Sfenner} 73575115Sfenner 736127668Sbms/// emitStoresForInitAfterMemset - For inits that 73775115Sfenner/// canEmitInitWithFewStoresAfterMemset returned true for, emit the scalar 73875115Sfenner/// stores that would be required. 73975115Sfennerstatic void emitStoresForInitAfterMemset(llvm::Constant *Init, llvm::Value *Loc, 74075115Sfenner bool isVolatile, CGBuilderTy &Builder) { 741127668Sbms assert(!Init->isNullValue() && !isa<llvm::UndefValue>(Init) && 74275115Sfenner "called emitStoresForInitAfterMemset for zero or undef value."); 74398524Sfenner 74475115Sfenner if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) || 74575115Sfenner isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) || 746127668Sbms isa<llvm::ConstantExpr>(Init)) { 74775115Sfenner Builder.CreateStore(Init, Loc, isVolatile); 748127668Sbms return; 74975115Sfenner } 750162017Ssam 75175115Sfenner if (llvm::ConstantDataSequential *CDS = 75275115Sfenner dyn_cast<llvm::ConstantDataSequential>(Init)) { 753127668Sbms for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) { 75475115Sfenner llvm::Constant *Elt = CDS->getElementAsConstant(i); 75575115Sfenner 75675115Sfenner // If necessary, get a pointer to the element and emit it. 75775115Sfenner if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt)) 75875115Sfenner emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i), 75975115Sfenner isVolatile, Builder); 76075115Sfenner } 76175115Sfenner return; 76275115Sfenner } 76375115Sfenner 764127668Sbms assert((isa<llvm::ConstantStruct>(Init) || isa<llvm::ConstantArray>(Init)) && 76575115Sfenner "Unknown value type!"); 76675115Sfenner 76775115Sfenner for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) { 76875115Sfenner llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i)); 76975115Sfenner 770127668Sbms // If necessary, get a pointer to the element and emit it. 77175115Sfenner if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt)) 77275115Sfenner emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i), 773127668Sbms isVolatile, Builder); 77475115Sfenner } 77575115Sfenner} 77675115Sfenner 777127668Sbms 77875115Sfenner/// shouldUseMemSetPlusStoresToInitialize - Decide whether we should use memset 77975115Sfenner/// plus some stores to initialize a local variable instead of using a memcpy 78075115Sfenner/// from a constant global. It is beneficial to use memset if the global is all 781127668Sbms/// zeros, or mostly zeros and large. 78275115Sfennerstatic bool shouldUseMemSetPlusStoresToInitialize(llvm::Constant *Init, 783127668Sbms uint64_t GlobalSize) { 78475115Sfenner // If a global is all zeros, always use a memset. 78575115Sfenner if (isa<llvm::ConstantAggregateZero>(Init)) return true; 78675115Sfenner 787127668Sbms // If a non-zero global is <= 32 bytes, always use a memcpy. If it is large, 78875115Sfenner // do it if it will require 6 or fewer scalar stores. 78975115Sfenner // TODO: Should budget depends on the size? Avoiding a large global warrants 79075115Sfenner // plopping in more stores. 79175115Sfenner unsigned StoreBudget = 6; 792127668Sbms uint64_t SizeLimit = 32; 79375115Sfenner 794127668Sbms return GlobalSize > SizeLimit && 79575115Sfenner canEmitInitWithFewStoresAfterMemset(Init, StoreBudget); 79675115Sfenner} 797127668Sbms 79875115Sfenner/// Should we use the LLVM lifetime intrinsics for the given local variable? 799127668Sbmsstatic bool shouldUseLifetimeMarkers(CodeGenFunction &CGF, const VarDecl &D, 80075115Sfenner unsigned Size) { 80175115Sfenner // Always emit lifetime markers in -fsanitize=use-after-scope mode. 80275115Sfenner if (CGF.getLangOpts().Sanitize.UseAfterScope) 803127668Sbms return true; 80475115Sfenner // For now, only in optimized builds. 80575115Sfenner if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0) 80675115Sfenner return false; 807127668Sbms 808162017Ssam // Limit the size of marked objects to 32 bytes. We don't want to increase 80975115Sfenner // compile time by marking tiny objects. 81075115Sfenner unsigned SizeThreshold = 32; 81175115Sfenner 81275115Sfenner return Size > SizeThreshold; 81375115Sfenner} 81475115Sfenner 81575115Sfenner 816127668Sbms/// EmitAutoVarDecl - Emit code and set up an entry in LocalDeclMap for a 81775115Sfenner/// variable declaration with auto, register, or no storage class specifier. 81875115Sfenner/// These turn into simple stack objects, or GlobalValues depending on target. 81975115Sfennervoid CodeGenFunction::EmitAutoVarDecl(const VarDecl &D) { 82075115Sfenner AutoVarEmission emission = EmitAutoVarAlloca(D); 82175115Sfenner EmitAutoVarInit(emission); 82275115Sfenner EmitAutoVarCleanups(emission); 82375115Sfenner} 824162017Ssam 825127668Sbms/// EmitAutoVarAlloca - Emit the alloca and debug information for a 82675115Sfenner/// local variable. Does not emit initalization or destruction. 827162017SsamCodeGenFunction::AutoVarEmission 82875115SfennerCodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) { 82975115Sfenner QualType Ty = D.getType(); 83075115Sfenner 83175115Sfenner AutoVarEmission emission(D); 83275115Sfenner 833162017Ssam bool isByRef = D.hasAttr<BlocksAttr>(); 83475115Sfenner emission.IsByRef = isByRef; 83575115Sfenner 836162017Ssam CharUnits alignment = getContext().getDeclAlign(&D); 837127668Sbms emission.Alignment = alignment; 83875115Sfenner 83975115Sfenner // If the type is variably-modified, emit all the VLA sizes for it. 840162017Ssam if (Ty->isVariablyModifiedType()) 841162017Ssam EmitVariablyModifiedType(Ty); 842162017Ssam 843162017Ssam llvm::Value *DeclPtr; 844162017Ssam if (Ty->isConstantSizeType()) { 845162017Ssam bool NRVO = getLangOpts().ElideConstructors && 846162017Ssam D.isNRVOVariable(); 847162017Ssam 848162017Ssam // If this value is an array or struct with a statically determinable 84998524Sfenner // constant initializer, there are optimizations we can do. 850162017Ssam // 851162017Ssam // TODO: We should constant-evaluate the initializer of any variable, 852162017Ssam // as long as it is initialized by a constant expression. Currently, 853162017Ssam // isConstantInitializer produces wrong answers for structs with 854127668Sbms // reference or bitfield members, and a few other cases, and checking 85598524Sfenner // for POD-ness protects us from some of these. 856162017Ssam if (D.getInit() && (Ty->isArrayType() || Ty->isRecordType()) && 85775115Sfenner (D.isConstexpr() || 858162017Ssam ((Ty.isPODType(getContext()) || 859162017Ssam getContext().getBaseElementType(Ty)->isObjCObjectPointerType()) && 860162017Ssam D.getInit()->isConstantInitializer(getContext(), false)))) { 861162017Ssam 862162017Ssam // If the variable's a const type, and it's neither an NRVO 863162017Ssam // candidate nor a __block variable and has no mutable members, 864162017Ssam // emit it as a global instead. 865162017Ssam if (CGM.getCodeGenOpts().MergeAllConstants && !NRVO && !isByRef && 866162017Ssam CGM.isTypeConstant(Ty, true)) { 867162017Ssam EmitStaticVarDecl(D, llvm::GlobalValue::InternalLinkage); 86875115Sfenner 869162017Ssam emission.Address = 0; // signal this condition to later callbacks 870162017Ssam assert(emission.wasEmittedAsGlobal()); 871162017Ssam return emission; 872162017Ssam } 873162017Ssam 874162017Ssam // Otherwise, tell the initialization code that we're in this case. 875162017Ssam emission.IsConstantAggregate = true; 876162017Ssam } 877127668Sbms 87875115Sfenner // A normal fixed sized variable becomes an alloca in the entry block, 879146773Ssam // unless it's an NRVO variable. 880162017Ssam llvm::Type *LTy = ConvertTypeForMem(Ty); 881146773Ssam 882127668Sbms if (NRVO) { 88375115Sfenner // The named return value optimization: allocate this variable in the 88475115Sfenner // return slot, so that we can elide the copy when returning this 88575115Sfenner // variable (C++0x [class.copy]p34). 886162017Ssam DeclPtr = ReturnValue; 887162017Ssam 888162017Ssam if (const RecordType *RecordTy = Ty->getAs<RecordType>()) { 889162017Ssam if (!cast<CXXRecordDecl>(RecordTy->getDecl())->hasTrivialDestructor()) { 89075115Sfenner // Create a flag that is used to indicate when the NRVO was applied 89175115Sfenner // to this variable. Set it to zero to indicate that NRVO was not 89275115Sfenner // applied. 89375115Sfenner llvm::Value *Zero = Builder.getFalse(); 89475115Sfenner llvm::Value *NRVOFlag = CreateTempAlloca(Zero->getType(), "nrvo"); 89575115Sfenner EnsureInsertPoint(); 89675115Sfenner Builder.CreateStore(Zero, NRVOFlag); 897127668Sbms 89875115Sfenner // Record the NRVO flag for this variable. 899162017Ssam NRVOFlags[&D] = NRVOFlag; 90075115Sfenner emission.NRVOFlag = NRVOFlag; 901127668Sbms } 90298524Sfenner } 90398524Sfenner } else { 90498524Sfenner if (isByRef) 90598524Sfenner LTy = BuildByRefType(&D); 90698524Sfenner 90798524Sfenner llvm::AllocaInst *Alloc = CreateTempAlloca(LTy); 90898524Sfenner Alloc->setName(D.getName()); 909162017Ssam 910162017Ssam CharUnits allocaAlignment = alignment; 911127668Sbms if (isByRef) 912127668Sbms allocaAlignment = std::max(allocaAlignment, 913127668Sbms getContext().toCharUnitsFromBits(getTarget().getPointerAlign(0))); 914127668Sbms Alloc->setAlignment(allocaAlignment.getQuantity()); 915127668Sbms DeclPtr = Alloc; 916127668Sbms 917162017Ssam // Emit a lifetime intrinsic if meaningful. There's no point 918127668Sbms // in doing this if we don't have a valid insertion point (?). 919127668Sbms uint64_t size = CGM.getDataLayout().getTypeAllocSize(LTy); 920127668Sbms if (HaveInsertPoint() && shouldUseLifetimeMarkers(*this, D, size)) { 921127668Sbms llvm::Value *sizeV = llvm::ConstantInt::get(Int64Ty, size); 922162017Ssam 923127668Sbms emission.SizeForLifetimeMarkers = sizeV; 924127668Sbms llvm::Value *castAddr = Builder.CreateBitCast(Alloc, Int8PtrTy); 925127668Sbms Builder.CreateCall2(CGM.getLLVMLifetimeStartFn(), sizeV, castAddr) 92675115Sfenner ->setDoesNotThrow(); 927127668Sbms } else { 928127668Sbms assert(!emission.useLifetimeMarkers()); 929127668Sbms } 93075115Sfenner } 931162017Ssam } else { 932162017Ssam EnsureInsertPoint(); 933162017Ssam 934162017Ssam if (!DidCallStackSave) { 935162017Ssam // Save the stack. 936162017Ssam llvm::Value *Stack = CreateTempAlloca(Int8PtrTy, "saved_stack"); 93775115Sfenner 938 llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stacksave); 939 llvm::Value *V = Builder.CreateCall(F); 940 941 Builder.CreateStore(V, Stack); 942 943 DidCallStackSave = true; 944 945 // Push a cleanup block and restore the stack there. 946 // FIXME: in general circumstances, this should be an EH cleanup. 947 EHStack.pushCleanup<CallStackRestore>(NormalCleanup, Stack); 948 } 949 950 llvm::Value *elementCount; 951 QualType elementType; 952 llvm::tie(elementCount, elementType) = getVLASize(Ty); 953 954 llvm::Type *llvmTy = ConvertTypeForMem(elementType); 955 956 // Allocate memory for the array. 957 llvm::AllocaInst *vla = Builder.CreateAlloca(llvmTy, elementCount, "vla"); 958 vla->setAlignment(alignment.getQuantity()); 959 960 DeclPtr = vla; 961 } 962 963 llvm::Value *&DMEntry = LocalDeclMap[&D]; 964 assert(DMEntry == 0 && "Decl already exists in localdeclmap!"); 965 DMEntry = DeclPtr; 966 emission.Address = DeclPtr; 967 968 // Emit debug info for local var declaration. 969 if (HaveInsertPoint()) 970 if (CGDebugInfo *DI = getDebugInfo()) { 971 if (CGM.getCodeGenOpts().getDebugInfo() 972 >= CodeGenOptions::LimitedDebugInfo) { 973 DI->setLocation(D.getLocation()); 974 DI->EmitDeclareOfAutoVariable(&D, DeclPtr, Builder); 975 } 976 } 977 978 if (D.hasAttr<AnnotateAttr>()) 979 EmitVarAnnotations(&D, emission.Address); 980 981 return emission; 982} 983 984/// Determines whether the given __block variable is potentially 985/// captured by the given expression. 986static bool isCapturedBy(const VarDecl &var, const Expr *e) { 987 // Skip the most common kinds of expressions that make 988 // hierarchy-walking expensive. 989 e = e->IgnoreParenCasts(); 990 991 if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) { 992 const BlockDecl *block = be->getBlockDecl(); 993 for (BlockDecl::capture_const_iterator i = block->capture_begin(), 994 e = block->capture_end(); i != e; ++i) { 995 if (i->getVariable() == &var) 996 return true; 997 } 998 999 // No need to walk into the subexpressions. 1000 return false; 1001 } 1002 1003 if (const StmtExpr *SE = dyn_cast<StmtExpr>(e)) { 1004 const CompoundStmt *CS = SE->getSubStmt(); 1005 for (CompoundStmt::const_body_iterator BI = CS->body_begin(), 1006 BE = CS->body_end(); BI != BE; ++BI) 1007 if (Expr *E = dyn_cast<Expr>((*BI))) { 1008 if (isCapturedBy(var, E)) 1009 return true; 1010 } 1011 else if (DeclStmt *DS = dyn_cast<DeclStmt>((*BI))) { 1012 // special case declarations 1013 for (DeclStmt::decl_iterator I = DS->decl_begin(), E = DS->decl_end(); 1014 I != E; ++I) { 1015 if (VarDecl *VD = dyn_cast<VarDecl>((*I))) { 1016 Expr *Init = VD->getInit(); 1017 if (Init && isCapturedBy(var, Init)) 1018 return true; 1019 } 1020 } 1021 } 1022 else 1023 // FIXME. Make safe assumption assuming arbitrary statements cause capturing. 1024 // Later, provide code to poke into statements for capture analysis. 1025 return true; 1026 return false; 1027 } 1028 1029 for (Stmt::const_child_range children = e->children(); children; ++children) 1030 if (isCapturedBy(var, cast<Expr>(*children))) 1031 return true; 1032 1033 return false; 1034} 1035 1036/// \brief Determine whether the given initializer is trivial in the sense 1037/// that it requires no code to be generated. 1038static bool isTrivialInitializer(const Expr *Init) { 1039 if (!Init) 1040 return true; 1041 1042 if (const CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init)) 1043 if (CXXConstructorDecl *Constructor = Construct->getConstructor()) 1044 if (Constructor->isTrivial() && 1045 Constructor->isDefaultConstructor() && 1046 !Construct->requiresZeroInitialization()) 1047 return true; 1048 1049 return false; 1050} 1051void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) { 1052 assert(emission.Variable && "emission was not valid!"); 1053 1054 // If this was emitted as a global constant, we're done. 1055 if (emission.wasEmittedAsGlobal()) return; 1056 1057 const VarDecl &D = *emission.Variable; 1058 QualType type = D.getType(); 1059 1060 // If this local has an initializer, emit it now. 1061 const Expr *Init = D.getInit(); 1062 1063 // If we are at an unreachable point, we don't need to emit the initializer 1064 // unless it contains a label. 1065 if (!HaveInsertPoint()) { 1066 if (!Init || !ContainsLabel(Init)) return; 1067 EnsureInsertPoint(); 1068 } 1069 1070 // Initialize the structure of a __block variable. 1071 if (emission.IsByRef) 1072 emitByrefStructureInit(emission); 1073 1074 if (isTrivialInitializer(Init)) 1075 return; 1076 1077 CharUnits alignment = emission.Alignment; 1078 1079 // Check whether this is a byref variable that's potentially 1080 // captured and moved by its own initializer. If so, we'll need to 1081 // emit the initializer first, then copy into the variable. 1082 bool capturedByInit = emission.IsByRef && isCapturedBy(D, Init); 1083 1084 llvm::Value *Loc = 1085 capturedByInit ? emission.Address : emission.getObjectAddress(*this); 1086 1087 llvm::Constant *constant = 0; 1088 if (emission.IsConstantAggregate || D.isConstexpr()) { 1089 assert(!capturedByInit && "constant init contains a capturing block?"); 1090 constant = CGM.EmitConstantInit(D, this); 1091 } 1092 1093 if (!constant) { 1094 LValue lv = MakeAddrLValue(Loc, type, alignment); 1095 lv.setNonGC(true); 1096 return EmitExprAsInit(Init, &D, lv, capturedByInit); 1097 } 1098 1099 if (!emission.IsConstantAggregate) { 1100 // For simple scalar/complex initialization, store the value directly. 1101 LValue lv = MakeAddrLValue(Loc, type, alignment); 1102 lv.setNonGC(true); 1103 return EmitStoreThroughLValue(RValue::get(constant), lv, true); 1104 } 1105 1106 // If this is a simple aggregate initialization, we can optimize it 1107 // in various ways. 1108 bool isVolatile = type.isVolatileQualified(); 1109 1110 llvm::Value *SizeVal = 1111 llvm::ConstantInt::get(IntPtrTy, 1112 getContext().getTypeSizeInChars(type).getQuantity()); 1113 1114 llvm::Type *BP = Int8PtrTy; 1115 if (Loc->getType() != BP) 1116 Loc = Builder.CreateBitCast(Loc, BP); 1117 1118 // If the initializer is all or mostly zeros, codegen with memset then do 1119 // a few stores afterward. 1120 if (shouldUseMemSetPlusStoresToInitialize(constant, 1121 CGM.getDataLayout().getTypeAllocSize(constant->getType()))) { 1122 Builder.CreateMemSet(Loc, llvm::ConstantInt::get(Int8Ty, 0), SizeVal, 1123 alignment.getQuantity(), isVolatile); 1124 // Zero and undef don't require a stores. 1125 if (!constant->isNullValue() && !isa<llvm::UndefValue>(constant)) { 1126 Loc = Builder.CreateBitCast(Loc, constant->getType()->getPointerTo()); 1127 emitStoresForInitAfterMemset(constant, Loc, isVolatile, Builder); 1128 } 1129 } else { 1130 // Otherwise, create a temporary global with the initializer then 1131 // memcpy from the global to the alloca. 1132 std::string Name = GetStaticDeclName(*this, D, "."); 1133 llvm::GlobalVariable *GV = 1134 new llvm::GlobalVariable(CGM.getModule(), constant->getType(), true, 1135 llvm::GlobalValue::PrivateLinkage, 1136 constant, Name); 1137 GV->setAlignment(alignment.getQuantity()); 1138 GV->setUnnamedAddr(true); 1139 1140 llvm::Value *SrcPtr = GV; 1141 if (SrcPtr->getType() != BP) 1142 SrcPtr = Builder.CreateBitCast(SrcPtr, BP); 1143 1144 Builder.CreateMemCpy(Loc, SrcPtr, SizeVal, alignment.getQuantity(), 1145 isVolatile); 1146 } 1147} 1148 1149/// Emit an expression as an initializer for a variable at the given 1150/// location. The expression is not necessarily the normal 1151/// initializer for the variable, and the address is not necessarily 1152/// its normal location. 1153/// 1154/// \param init the initializing expression 1155/// \param var the variable to act as if we're initializing 1156/// \param loc the address to initialize; its type is a pointer 1157/// to the LLVM mapping of the variable's type 1158/// \param alignment the alignment of the address 1159/// \param capturedByInit true if the variable is a __block variable 1160/// whose address is potentially changed by the initializer 1161void CodeGenFunction::EmitExprAsInit(const Expr *init, 1162 const ValueDecl *D, 1163 LValue lvalue, 1164 bool capturedByInit) { 1165 QualType type = D->getType(); 1166 1167 if (type->isReferenceType()) { 1168 RValue rvalue = EmitReferenceBindingToExpr(init); 1169 if (capturedByInit) 1170 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D)); 1171 EmitStoreThroughLValue(rvalue, lvalue, true); 1172 return; 1173 } 1174 switch (getEvaluationKind(type)) { 1175 case TEK_Scalar: 1176 EmitScalarInit(init, D, lvalue, capturedByInit); 1177 return; 1178 case TEK_Complex: { 1179 ComplexPairTy complex = EmitComplexExpr(init); 1180 if (capturedByInit) 1181 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D)); 1182 EmitStoreOfComplex(complex, lvalue, /*init*/ true); 1183 return; 1184 } 1185 case TEK_Aggregate: 1186 if (type->isAtomicType()) { 1187 EmitAtomicInit(const_cast<Expr*>(init), lvalue); 1188 } else { 1189 // TODO: how can we delay here if D is captured by its initializer? 1190 EmitAggExpr(init, AggValueSlot::forLValue(lvalue, 1191 AggValueSlot::IsDestructed, 1192 AggValueSlot::DoesNotNeedGCBarriers, 1193 AggValueSlot::IsNotAliased)); 1194 } 1195 return; 1196 } 1197 llvm_unreachable("bad evaluation kind"); 1198} 1199 1200/// Enter a destroy cleanup for the given local variable. 1201void CodeGenFunction::emitAutoVarTypeCleanup( 1202 const CodeGenFunction::AutoVarEmission &emission, 1203 QualType::DestructionKind dtorKind) { 1204 assert(dtorKind != QualType::DK_none); 1205 1206 // Note that for __block variables, we want to destroy the 1207 // original stack object, not the possibly forwarded object. 1208 llvm::Value *addr = emission.getObjectAddress(*this); 1209 1210 const VarDecl *var = emission.Variable; 1211 QualType type = var->getType(); 1212 1213 CleanupKind cleanupKind = NormalAndEHCleanup; 1214 CodeGenFunction::Destroyer *destroyer = 0; 1215 1216 switch (dtorKind) { 1217 case QualType::DK_none: 1218 llvm_unreachable("no cleanup for trivially-destructible variable"); 1219 1220 case QualType::DK_cxx_destructor: 1221 // If there's an NRVO flag on the emission, we need a different 1222 // cleanup. 1223 if (emission.NRVOFlag) { 1224 assert(!type->isArrayType()); 1225 CXXDestructorDecl *dtor = type->getAsCXXRecordDecl()->getDestructor(); 1226 EHStack.pushCleanup<DestroyNRVOVariable>(cleanupKind, addr, dtor, 1227 emission.NRVOFlag); 1228 return; 1229 } 1230 break; 1231 1232 case QualType::DK_objc_strong_lifetime: 1233 // Suppress cleanups for pseudo-strong variables. 1234 if (var->isARCPseudoStrong()) return; 1235 1236 // Otherwise, consider whether to use an EH cleanup or not. 1237 cleanupKind = getARCCleanupKind(); 1238 1239 // Use the imprecise destroyer by default. 1240 if (!var->hasAttr<ObjCPreciseLifetimeAttr>()) 1241 destroyer = CodeGenFunction::destroyARCStrongImprecise; 1242 break; 1243 1244 case QualType::DK_objc_weak_lifetime: 1245 break; 1246 } 1247 1248 // If we haven't chosen a more specific destroyer, use the default. 1249 if (!destroyer) destroyer = getDestroyer(dtorKind); 1250 1251 // Use an EH cleanup in array destructors iff the destructor itself 1252 // is being pushed as an EH cleanup. 1253 bool useEHCleanup = (cleanupKind & EHCleanup); 1254 EHStack.pushCleanup<DestroyObject>(cleanupKind, addr, type, destroyer, 1255 useEHCleanup); 1256} 1257 1258void CodeGenFunction::EmitAutoVarCleanups(const AutoVarEmission &emission) { 1259 assert(emission.Variable && "emission was not valid!"); 1260 1261 // If this was emitted as a global constant, we're done. 1262 if (emission.wasEmittedAsGlobal()) return; 1263 1264 // If we don't have an insertion point, we're done. Sema prevents 1265 // us from jumping into any of these scopes anyway. 1266 if (!HaveInsertPoint()) return; 1267 1268 const VarDecl &D = *emission.Variable; 1269 1270 // Make sure we call @llvm.lifetime.end. This needs to happen 1271 // *last*, so the cleanup needs to be pushed *first*. 1272 if (emission.useLifetimeMarkers()) { 1273 EHStack.pushCleanup<CallLifetimeEnd>(NormalCleanup, 1274 emission.getAllocatedAddress(), 1275 emission.getSizeForLifetimeMarkers()); 1276 } 1277 1278 // Check the type for a cleanup. 1279 if (QualType::DestructionKind dtorKind = D.getType().isDestructedType()) 1280 emitAutoVarTypeCleanup(emission, dtorKind); 1281 1282 // In GC mode, honor objc_precise_lifetime. 1283 if (getLangOpts().getGC() != LangOptions::NonGC && 1284 D.hasAttr<ObjCPreciseLifetimeAttr>()) { 1285 EHStack.pushCleanup<ExtendGCLifetime>(NormalCleanup, &D); 1286 } 1287 1288 // Handle the cleanup attribute. 1289 if (const CleanupAttr *CA = D.getAttr<CleanupAttr>()) { 1290 const FunctionDecl *FD = CA->getFunctionDecl(); 1291 1292 llvm::Constant *F = CGM.GetAddrOfFunction(FD); 1293 assert(F && "Could not find function!"); 1294 1295 const CGFunctionInfo &Info = CGM.getTypes().arrangeFunctionDeclaration(FD); 1296 EHStack.pushCleanup<CallCleanupFunction>(NormalAndEHCleanup, F, &Info, &D); 1297 } 1298 1299 // If this is a block variable, call _Block_object_destroy 1300 // (on the unforwarded address). 1301 if (emission.IsByRef) 1302 enterByrefCleanup(emission); 1303} 1304 1305CodeGenFunction::Destroyer * 1306CodeGenFunction::getDestroyer(QualType::DestructionKind kind) { 1307 switch (kind) { 1308 case QualType::DK_none: llvm_unreachable("no destroyer for trivial dtor"); 1309 case QualType::DK_cxx_destructor: 1310 return destroyCXXObject; 1311 case QualType::DK_objc_strong_lifetime: 1312 return destroyARCStrongPrecise; 1313 case QualType::DK_objc_weak_lifetime: 1314 return destroyARCWeak; 1315 } 1316 llvm_unreachable("Unknown DestructionKind"); 1317} 1318 1319/// pushEHDestroy - Push the standard destructor for the given type as 1320/// an EH-only cleanup. 1321void CodeGenFunction::pushEHDestroy(QualType::DestructionKind dtorKind, 1322 llvm::Value *addr, QualType type) { 1323 assert(dtorKind && "cannot push destructor for trivial type"); 1324 assert(needsEHCleanup(dtorKind)); 1325 1326 pushDestroy(EHCleanup, addr, type, getDestroyer(dtorKind), true); 1327} 1328 1329/// pushDestroy - Push the standard destructor for the given type as 1330/// at least a normal cleanup. 1331void CodeGenFunction::pushDestroy(QualType::DestructionKind dtorKind, 1332 llvm::Value *addr, QualType type) { 1333 assert(dtorKind && "cannot push destructor for trivial type"); 1334 1335 CleanupKind cleanupKind = getCleanupKind(dtorKind); 1336 pushDestroy(cleanupKind, addr, type, getDestroyer(dtorKind), 1337 cleanupKind & EHCleanup); 1338} 1339 1340void CodeGenFunction::pushDestroy(CleanupKind cleanupKind, llvm::Value *addr, 1341 QualType type, Destroyer *destroyer, 1342 bool useEHCleanupForArray) { 1343 pushFullExprCleanup<DestroyObject>(cleanupKind, addr, type, 1344 destroyer, useEHCleanupForArray); 1345} 1346 1347void CodeGenFunction::pushLifetimeExtendedDestroy( 1348 CleanupKind cleanupKind, llvm::Value *addr, QualType type, 1349 Destroyer *destroyer, bool useEHCleanupForArray) { 1350 assert(!isInConditionalBranch() && 1351 "performing lifetime extension from within conditional"); 1352 1353 // Push an EH-only cleanup for the object now. 1354 // FIXME: When popping normal cleanups, we need to keep this EH cleanup 1355 // around in case a temporary's destructor throws an exception. 1356 if (cleanupKind & EHCleanup) 1357 EHStack.pushCleanup<DestroyObject>( 1358 static_cast<CleanupKind>(cleanupKind & ~NormalCleanup), addr, type, 1359 destroyer, useEHCleanupForArray); 1360 1361 // Remember that we need to push a full cleanup for the object at the 1362 // end of the full-expression. 1363 pushCleanupAfterFullExpr<DestroyObject>( 1364 cleanupKind, addr, type, destroyer, useEHCleanupForArray); 1365} 1366 1367/// emitDestroy - Immediately perform the destruction of the given 1368/// object. 1369/// 1370/// \param addr - the address of the object; a type* 1371/// \param type - the type of the object; if an array type, all 1372/// objects are destroyed in reverse order 1373/// \param destroyer - the function to call to destroy individual 1374/// elements 1375/// \param useEHCleanupForArray - whether an EH cleanup should be 1376/// used when destroying array elements, in case one of the 1377/// destructions throws an exception 1378void CodeGenFunction::emitDestroy(llvm::Value *addr, QualType type, 1379 Destroyer *destroyer, 1380 bool useEHCleanupForArray) { 1381 const ArrayType *arrayType = getContext().getAsArrayType(type); 1382 if (!arrayType) 1383 return destroyer(*this, addr, type); 1384 1385 llvm::Value *begin = addr; 1386 llvm::Value *length = emitArrayLength(arrayType, type, begin); 1387 1388 // Normally we have to check whether the array is zero-length. 1389 bool checkZeroLength = true; 1390 1391 // But if the array length is constant, we can suppress that. 1392 if (llvm::ConstantInt *constLength = dyn_cast<llvm::ConstantInt>(length)) { 1393 // ...and if it's constant zero, we can just skip the entire thing. 1394 if (constLength->isZero()) return; 1395 checkZeroLength = false; 1396 } 1397 1398 llvm::Value *end = Builder.CreateInBoundsGEP(begin, length); 1399 emitArrayDestroy(begin, end, type, destroyer, 1400 checkZeroLength, useEHCleanupForArray); 1401} 1402 1403/// emitArrayDestroy - Destroys all the elements of the given array, 1404/// beginning from last to first. The array cannot be zero-length. 1405/// 1406/// \param begin - a type* denoting the first element of the array 1407/// \param end - a type* denoting one past the end of the array 1408/// \param type - the element type of the array 1409/// \param destroyer - the function to call to destroy elements 1410/// \param useEHCleanup - whether to push an EH cleanup to destroy 1411/// the remaining elements in case the destruction of a single 1412/// element throws 1413void CodeGenFunction::emitArrayDestroy(llvm::Value *begin, 1414 llvm::Value *end, 1415 QualType type, 1416 Destroyer *destroyer, 1417 bool checkZeroLength, 1418 bool useEHCleanup) { 1419 assert(!type->isArrayType()); 1420 1421 // The basic structure here is a do-while loop, because we don't 1422 // need to check for the zero-element case. 1423 llvm::BasicBlock *bodyBB = createBasicBlock("arraydestroy.body"); 1424 llvm::BasicBlock *doneBB = createBasicBlock("arraydestroy.done"); 1425 1426 if (checkZeroLength) { 1427 llvm::Value *isEmpty = Builder.CreateICmpEQ(begin, end, 1428 "arraydestroy.isempty"); 1429 Builder.CreateCondBr(isEmpty, doneBB, bodyBB); 1430 } 1431 1432 // Enter the loop body, making that address the current address. 1433 llvm::BasicBlock *entryBB = Builder.GetInsertBlock(); 1434 EmitBlock(bodyBB); 1435 llvm::PHINode *elementPast = 1436 Builder.CreatePHI(begin->getType(), 2, "arraydestroy.elementPast"); 1437 elementPast->addIncoming(end, entryBB); 1438 1439 // Shift the address back by one element. 1440 llvm::Value *negativeOne = llvm::ConstantInt::get(SizeTy, -1, true); 1441 llvm::Value *element = Builder.CreateInBoundsGEP(elementPast, negativeOne, 1442 "arraydestroy.element"); 1443 1444 if (useEHCleanup) 1445 pushRegularPartialArrayCleanup(begin, element, type, destroyer); 1446 1447 // Perform the actual destruction there. 1448 destroyer(*this, element, type); 1449 1450 if (useEHCleanup) 1451 PopCleanupBlock(); 1452 1453 // Check whether we've reached the end. 1454 llvm::Value *done = Builder.CreateICmpEQ(element, begin, "arraydestroy.done"); 1455 Builder.CreateCondBr(done, doneBB, bodyBB); 1456 elementPast->addIncoming(element, Builder.GetInsertBlock()); 1457 1458 // Done. 1459 EmitBlock(doneBB); 1460} 1461 1462/// Perform partial array destruction as if in an EH cleanup. Unlike 1463/// emitArrayDestroy, the element type here may still be an array type. 1464static void emitPartialArrayDestroy(CodeGenFunction &CGF, 1465 llvm::Value *begin, llvm::Value *end, 1466 QualType type, 1467 CodeGenFunction::Destroyer *destroyer) { 1468 // If the element type is itself an array, drill down. 1469 unsigned arrayDepth = 0; 1470 while (const ArrayType *arrayType = CGF.getContext().getAsArrayType(type)) { 1471 // VLAs don't require a GEP index to walk into. 1472 if (!isa<VariableArrayType>(arrayType)) 1473 arrayDepth++; 1474 type = arrayType->getElementType(); 1475 } 1476 1477 if (arrayDepth) { 1478 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, arrayDepth+1); 1479 1480 SmallVector<llvm::Value*,4> gepIndices(arrayDepth, zero); 1481 begin = CGF.Builder.CreateInBoundsGEP(begin, gepIndices, "pad.arraybegin"); 1482 end = CGF.Builder.CreateInBoundsGEP(end, gepIndices, "pad.arrayend"); 1483 } 1484 1485 // Destroy the array. We don't ever need an EH cleanup because we 1486 // assume that we're in an EH cleanup ourselves, so a throwing 1487 // destructor causes an immediate terminate. 1488 CGF.emitArrayDestroy(begin, end, type, destroyer, 1489 /*checkZeroLength*/ true, /*useEHCleanup*/ false); 1490} 1491 1492namespace { 1493 /// RegularPartialArrayDestroy - a cleanup which performs a partial 1494 /// array destroy where the end pointer is regularly determined and 1495 /// does not need to be loaded from a local. 1496 class RegularPartialArrayDestroy : public EHScopeStack::Cleanup { 1497 llvm::Value *ArrayBegin; 1498 llvm::Value *ArrayEnd; 1499 QualType ElementType; 1500 CodeGenFunction::Destroyer *Destroyer; 1501 public: 1502 RegularPartialArrayDestroy(llvm::Value *arrayBegin, llvm::Value *arrayEnd, 1503 QualType elementType, 1504 CodeGenFunction::Destroyer *destroyer) 1505 : ArrayBegin(arrayBegin), ArrayEnd(arrayEnd), 1506 ElementType(elementType), Destroyer(destroyer) {} 1507 1508 void Emit(CodeGenFunction &CGF, Flags flags) { 1509 emitPartialArrayDestroy(CGF, ArrayBegin, ArrayEnd, 1510 ElementType, Destroyer); 1511 } 1512 }; 1513 1514 /// IrregularPartialArrayDestroy - a cleanup which performs a 1515 /// partial array destroy where the end pointer is irregularly 1516 /// determined and must be loaded from a local. 1517 class IrregularPartialArrayDestroy : public EHScopeStack::Cleanup { 1518 llvm::Value *ArrayBegin; 1519 llvm::Value *ArrayEndPointer; 1520 QualType ElementType; 1521 CodeGenFunction::Destroyer *Destroyer; 1522 public: 1523 IrregularPartialArrayDestroy(llvm::Value *arrayBegin, 1524 llvm::Value *arrayEndPointer, 1525 QualType elementType, 1526 CodeGenFunction::Destroyer *destroyer) 1527 : ArrayBegin(arrayBegin), ArrayEndPointer(arrayEndPointer), 1528 ElementType(elementType), Destroyer(destroyer) {} 1529 1530 void Emit(CodeGenFunction &CGF, Flags flags) { 1531 llvm::Value *arrayEnd = CGF.Builder.CreateLoad(ArrayEndPointer); 1532 emitPartialArrayDestroy(CGF, ArrayBegin, arrayEnd, 1533 ElementType, Destroyer); 1534 } 1535 }; 1536} 1537 1538/// pushIrregularPartialArrayCleanup - Push an EH cleanup to destroy 1539/// already-constructed elements of the given array. The cleanup 1540/// may be popped with DeactivateCleanupBlock or PopCleanupBlock. 1541/// 1542/// \param elementType - the immediate element type of the array; 1543/// possibly still an array type 1544void CodeGenFunction::pushIrregularPartialArrayCleanup(llvm::Value *arrayBegin, 1545 llvm::Value *arrayEndPointer, 1546 QualType elementType, 1547 Destroyer *destroyer) { 1548 pushFullExprCleanup<IrregularPartialArrayDestroy>(EHCleanup, 1549 arrayBegin, arrayEndPointer, 1550 elementType, destroyer); 1551} 1552 1553/// pushRegularPartialArrayCleanup - Push an EH cleanup to destroy 1554/// already-constructed elements of the given array. The cleanup 1555/// may be popped with DeactivateCleanupBlock or PopCleanupBlock. 1556/// 1557/// \param elementType - the immediate element type of the array; 1558/// possibly still an array type 1559void CodeGenFunction::pushRegularPartialArrayCleanup(llvm::Value *arrayBegin, 1560 llvm::Value *arrayEnd, 1561 QualType elementType, 1562 Destroyer *destroyer) { 1563 pushFullExprCleanup<RegularPartialArrayDestroy>(EHCleanup, 1564 arrayBegin, arrayEnd, 1565 elementType, destroyer); 1566} 1567 1568/// Lazily declare the @llvm.lifetime.start intrinsic. 1569llvm::Constant *CodeGenModule::getLLVMLifetimeStartFn() { 1570 if (LifetimeStartFn) return LifetimeStartFn; 1571 LifetimeStartFn = llvm::Intrinsic::getDeclaration(&getModule(), 1572 llvm::Intrinsic::lifetime_start); 1573 return LifetimeStartFn; 1574} 1575 1576/// Lazily declare the @llvm.lifetime.end intrinsic. 1577llvm::Constant *CodeGenModule::getLLVMLifetimeEndFn() { 1578 if (LifetimeEndFn) return LifetimeEndFn; 1579 LifetimeEndFn = llvm::Intrinsic::getDeclaration(&getModule(), 1580 llvm::Intrinsic::lifetime_end); 1581 return LifetimeEndFn; 1582} 1583 1584namespace { 1585 /// A cleanup to perform a release of an object at the end of a 1586 /// function. This is used to balance out the incoming +1 of a 1587 /// ns_consumed argument when we can't reasonably do that just by 1588 /// not doing the initial retain for a __block argument. 1589 struct ConsumeARCParameter : EHScopeStack::Cleanup { 1590 ConsumeARCParameter(llvm::Value *param, 1591 ARCPreciseLifetime_t precise) 1592 : Param(param), Precise(precise) {} 1593 1594 llvm::Value *Param; 1595 ARCPreciseLifetime_t Precise; 1596 1597 void Emit(CodeGenFunction &CGF, Flags flags) { 1598 CGF.EmitARCRelease(Param, Precise); 1599 } 1600 }; 1601} 1602 1603/// Emit an alloca (or GlobalValue depending on target) 1604/// for the specified parameter and set up LocalDeclMap. 1605void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg, 1606 unsigned ArgNo) { 1607 // FIXME: Why isn't ImplicitParamDecl a ParmVarDecl? 1608 assert((isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)) && 1609 "Invalid argument to EmitParmDecl"); 1610 1611 Arg->setName(D.getName()); 1612 1613 QualType Ty = D.getType(); 1614 1615 // Use better IR generation for certain implicit parameters. 1616 if (isa<ImplicitParamDecl>(D)) { 1617 // The only implicit argument a block has is its literal. 1618 if (BlockInfo) { 1619 LocalDeclMap[&D] = Arg; 1620 llvm::Value *LocalAddr = 0; 1621 if (CGM.getCodeGenOpts().OptimizationLevel == 0) { 1622 // Allocate a stack slot to let the debug info survive the RA. 1623 llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty), 1624 D.getName() + ".addr"); 1625 Alloc->setAlignment(getContext().getDeclAlign(&D).getQuantity()); 1626 LValue lv = MakeAddrLValue(Alloc, Ty, getContext().getDeclAlign(&D)); 1627 EmitStoreOfScalar(Arg, lv, /* isInitialization */ true); 1628 LocalAddr = Builder.CreateLoad(Alloc); 1629 } 1630 1631 if (CGDebugInfo *DI = getDebugInfo()) { 1632 if (CGM.getCodeGenOpts().getDebugInfo() 1633 >= CodeGenOptions::LimitedDebugInfo) { 1634 DI->setLocation(D.getLocation()); 1635 DI->EmitDeclareOfBlockLiteralArgVariable(*BlockInfo, Arg, LocalAddr, Builder); 1636 } 1637 } 1638 1639 return; 1640 } 1641 } 1642 1643 llvm::Value *DeclPtr; 1644 bool HasNonScalarEvalKind = !CodeGenFunction::hasScalarEvaluationKind(Ty); 1645 // If this is an aggregate or variable sized value, reuse the input pointer. 1646 if (HasNonScalarEvalKind || !Ty->isConstantSizeType()) { 1647 DeclPtr = Arg; 1648 // Push a destructor cleanup for this parameter if the ABI requires it. 1649 if (HasNonScalarEvalKind && 1650 getTarget().getCXXABI().isArgumentDestroyedByCallee()) { 1651 if (const CXXRecordDecl *RD = Ty->getAsCXXRecordDecl()) { 1652 if (RD->hasNonTrivialDestructor()) 1653 pushDestroy(QualType::DK_cxx_destructor, DeclPtr, Ty); 1654 } 1655 } 1656 } else { 1657 // Otherwise, create a temporary to hold the value. 1658 llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty), 1659 D.getName() + ".addr"); 1660 CharUnits Align = getContext().getDeclAlign(&D); 1661 Alloc->setAlignment(Align.getQuantity()); 1662 DeclPtr = Alloc; 1663 1664 bool doStore = true; 1665 1666 Qualifiers qs = Ty.getQualifiers(); 1667 LValue lv = MakeAddrLValue(DeclPtr, Ty, Align); 1668 if (Qualifiers::ObjCLifetime lt = qs.getObjCLifetime()) { 1669 // We honor __attribute__((ns_consumed)) for types with lifetime. 1670 // For __strong, it's handled by just skipping the initial retain; 1671 // otherwise we have to balance out the initial +1 with an extra 1672 // cleanup to do the release at the end of the function. 1673 bool isConsumed = D.hasAttr<NSConsumedAttr>(); 1674 1675 // 'self' is always formally __strong, but if this is not an 1676 // init method then we don't want to retain it. 1677 if (D.isARCPseudoStrong()) { 1678 const ObjCMethodDecl *method = cast<ObjCMethodDecl>(CurCodeDecl); 1679 assert(&D == method->getSelfDecl()); 1680 assert(lt == Qualifiers::OCL_Strong); 1681 assert(qs.hasConst()); 1682 assert(method->getMethodFamily() != OMF_init); 1683 (void) method; 1684 lt = Qualifiers::OCL_ExplicitNone; 1685 } 1686 1687 if (lt == Qualifiers::OCL_Strong) { 1688 if (!isConsumed) { 1689 if (CGM.getCodeGenOpts().OptimizationLevel == 0) { 1690 // use objc_storeStrong(&dest, value) for retaining the 1691 // object. But first, store a null into 'dest' because 1692 // objc_storeStrong attempts to release its old value. 1693 llvm::Value *Null = CGM.EmitNullConstant(D.getType()); 1694 EmitStoreOfScalar(Null, lv, /* isInitialization */ true); 1695 EmitARCStoreStrongCall(lv.getAddress(), Arg, true); 1696 doStore = false; 1697 } 1698 else 1699 // Don't use objc_retainBlock for block pointers, because we 1700 // don't want to Block_copy something just because we got it 1701 // as a parameter. 1702 Arg = EmitARCRetainNonBlock(Arg); 1703 } 1704 } else { 1705 // Push the cleanup for a consumed parameter. 1706 if (isConsumed) { 1707 ARCPreciseLifetime_t precise = (D.hasAttr<ObjCPreciseLifetimeAttr>() 1708 ? ARCPreciseLifetime : ARCImpreciseLifetime); 1709 EHStack.pushCleanup<ConsumeARCParameter>(getARCCleanupKind(), Arg, 1710 precise); 1711 } 1712 1713 if (lt == Qualifiers::OCL_Weak) { 1714 EmitARCInitWeak(DeclPtr, Arg); 1715 doStore = false; // The weak init is a store, no need to do two. 1716 } 1717 } 1718 1719 // Enter the cleanup scope. 1720 EmitAutoVarWithLifetime(*this, D, DeclPtr, lt); 1721 } 1722 1723 // Store the initial value into the alloca. 1724 if (doStore) 1725 EmitStoreOfScalar(Arg, lv, /* isInitialization */ true); 1726 } 1727 1728 llvm::Value *&DMEntry = LocalDeclMap[&D]; 1729 assert(DMEntry == 0 && "Decl already exists in localdeclmap!"); 1730 DMEntry = DeclPtr; 1731 1732 // Emit debug info for param declaration. 1733 if (CGDebugInfo *DI = getDebugInfo()) { 1734 if (CGM.getCodeGenOpts().getDebugInfo() 1735 >= CodeGenOptions::LimitedDebugInfo) { 1736 DI->EmitDeclareOfArgVariable(&D, DeclPtr, ArgNo, Builder); 1737 } 1738 } 1739 1740 if (D.hasAttr<AnnotateAttr>()) 1741 EmitVarAnnotations(&D, DeclPtr); 1742} 1743