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Diffstat (limited to 'contrib/llvm/tools/clang/lib/CodeGen/CGDecl.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/CodeGen/CGDecl.cpp | 900 |
1 files changed, 900 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/CodeGen/CGDecl.cpp b/contrib/llvm/tools/clang/lib/CodeGen/CGDecl.cpp new file mode 100644 index 0000000..c027375 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/CGDecl.cpp @@ -0,0 +1,900 @@ +//===--- CGDecl.cpp - Emit LLVM Code for declarations ---------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This contains code to emit Decl nodes as LLVM code. +// +//===----------------------------------------------------------------------===// + +#include "CGDebugInfo.h" +#include "CodeGenFunction.h" +#include "CodeGenModule.h" +#include "clang/AST/ASTContext.h" +#include "clang/AST/CharUnits.h" +#include "clang/AST/Decl.h" +#include "clang/AST/DeclObjC.h" +#include "clang/Basic/SourceManager.h" +#include "clang/Basic/TargetInfo.h" +#include "clang/Frontend/CodeGenOptions.h" +#include "llvm/GlobalVariable.h" +#include "llvm/Intrinsics.h" +#include "llvm/Target/TargetData.h" +#include "llvm/Type.h" +using namespace clang; +using namespace CodeGen; + + +void CodeGenFunction::EmitDecl(const Decl &D) { + switch (D.getKind()) { + case Decl::TranslationUnit: + case Decl::Namespace: + case Decl::UnresolvedUsingTypename: + case Decl::ClassTemplateSpecialization: + case Decl::ClassTemplatePartialSpecialization: + case Decl::TemplateTypeParm: + case Decl::UnresolvedUsingValue: + case Decl::NonTypeTemplateParm: + case Decl::CXXMethod: + case Decl::CXXConstructor: + case Decl::CXXDestructor: + case Decl::CXXConversion: + case Decl::Field: + case Decl::IndirectField: + case Decl::ObjCIvar: + case Decl::ObjCAtDefsField: + case Decl::ParmVar: + case Decl::ImplicitParam: + case Decl::ClassTemplate: + case Decl::FunctionTemplate: + case Decl::TemplateTemplateParm: + case Decl::ObjCMethod: + case Decl::ObjCCategory: + case Decl::ObjCProtocol: + case Decl::ObjCInterface: + case Decl::ObjCCategoryImpl: + case Decl::ObjCImplementation: + case Decl::ObjCProperty: + case Decl::ObjCCompatibleAlias: + case Decl::AccessSpec: + case Decl::LinkageSpec: + case Decl::ObjCPropertyImpl: + case Decl::ObjCClass: + case Decl::ObjCForwardProtocol: + case Decl::FileScopeAsm: + case Decl::Friend: + case Decl::FriendTemplate: + case Decl::Block: + assert(0 && "Declaration should not be in declstmts!"); + case Decl::Function: // void X(); + case Decl::Record: // struct/union/class X; + case Decl::Enum: // enum X; + case Decl::EnumConstant: // enum ? { X = ? } + case Decl::CXXRecord: // struct/union/class X; [C++] + case Decl::Using: // using X; [C++] + case Decl::UsingShadow: + case Decl::UsingDirective: // using namespace X; [C++] + case Decl::NamespaceAlias: + case Decl::StaticAssert: // static_assert(X, ""); [C++0x] + case Decl::Label: // __label__ x; + // None of these decls require codegen support. + return; + + case Decl::Var: { + const VarDecl &VD = cast<VarDecl>(D); + assert(VD.isLocalVarDecl() && + "Should not see file-scope variables inside a function!"); + return EmitVarDecl(VD); + } + + case Decl::Typedef: // typedef int X; + case Decl::TypeAlias: { // using X = int; [C++0x] + const TypedefNameDecl &TD = cast<TypedefNameDecl>(D); + QualType Ty = TD.getUnderlyingType(); + + if (Ty->isVariablyModifiedType()) + EmitVLASize(Ty); + } + } +} + +/// EmitVarDecl - This method handles emission of any variable declaration +/// inside a function, including static vars etc. +void CodeGenFunction::EmitVarDecl(const VarDecl &D) { + switch (D.getStorageClass()) { + case SC_None: + case SC_Auto: + case SC_Register: + return EmitAutoVarDecl(D); + case SC_Static: { + llvm::GlobalValue::LinkageTypes Linkage = + llvm::GlobalValue::InternalLinkage; + + // If the function definition has some sort of weak linkage, its + // static variables should also be weak so that they get properly + // uniqued. We can't do this in C, though, because there's no + // standard way to agree on which variables are the same (i.e. + // there's no mangling). + if (getContext().getLangOptions().CPlusPlus) + if (llvm::GlobalValue::isWeakForLinker(CurFn->getLinkage())) + Linkage = CurFn->getLinkage(); + + return EmitStaticVarDecl(D, Linkage); + } + case SC_Extern: + case SC_PrivateExtern: + // Don't emit it now, allow it to be emitted lazily on its first use. + return; + } + + assert(0 && "Unknown storage class"); +} + +static std::string GetStaticDeclName(CodeGenFunction &CGF, const VarDecl &D, + const char *Separator) { + CodeGenModule &CGM = CGF.CGM; + if (CGF.getContext().getLangOptions().CPlusPlus) { + llvm::StringRef Name = CGM.getMangledName(&D); + return Name.str(); + } + + std::string ContextName; + if (!CGF.CurFuncDecl) { + // Better be in a block declared in global scope. + const NamedDecl *ND = cast<NamedDecl>(&D); + const DeclContext *DC = ND->getDeclContext(); + if (const BlockDecl *BD = dyn_cast<BlockDecl>(DC)) { + MangleBuffer Name; + CGM.getBlockMangledName(GlobalDecl(), Name, BD); + ContextName = Name.getString(); + } + else + assert(0 && "Unknown context for block static var decl"); + } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CGF.CurFuncDecl)) { + llvm::StringRef Name = CGM.getMangledName(FD); + ContextName = Name.str(); + } else if (isa<ObjCMethodDecl>(CGF.CurFuncDecl)) + ContextName = CGF.CurFn->getName(); + else + assert(0 && "Unknown context for static var decl"); + + return ContextName + Separator + D.getNameAsString(); +} + +llvm::GlobalVariable * +CodeGenFunction::CreateStaticVarDecl(const VarDecl &D, + const char *Separator, + llvm::GlobalValue::LinkageTypes Linkage) { + QualType Ty = D.getType(); + assert(Ty->isConstantSizeType() && "VLAs can't be static"); + + std::string Name = GetStaticDeclName(*this, D, Separator); + + const llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(Ty); + llvm::GlobalVariable *GV = + new llvm::GlobalVariable(CGM.getModule(), LTy, + Ty.isConstant(getContext()), Linkage, + CGM.EmitNullConstant(D.getType()), Name, 0, + D.isThreadSpecified(), + CGM.getContext().getTargetAddressSpace(Ty)); + GV->setAlignment(getContext().getDeclAlign(&D).getQuantity()); + if (Linkage != llvm::GlobalValue::InternalLinkage) + GV->setVisibility(CurFn->getVisibility()); + return GV; +} + +/// AddInitializerToStaticVarDecl - Add the initializer for 'D' to the +/// global variable that has already been created for it. If the initializer +/// has a different type than GV does, this may free GV and return a different +/// one. Otherwise it just returns GV. +llvm::GlobalVariable * +CodeGenFunction::AddInitializerToStaticVarDecl(const VarDecl &D, + llvm::GlobalVariable *GV) { + llvm::Constant *Init = CGM.EmitConstantExpr(D.getInit(), D.getType(), this); + + // If constant emission failed, then this should be a C++ static + // initializer. + if (!Init) { + if (!getContext().getLangOptions().CPlusPlus) + CGM.ErrorUnsupported(D.getInit(), "constant l-value expression"); + else if (Builder.GetInsertBlock()) { + // Since we have a static initializer, this global variable can't + // be constant. + GV->setConstant(false); + + EmitCXXGuardedInit(D, GV); + } + return GV; + } + + // The initializer may differ in type from the global. Rewrite + // the global to match the initializer. (We have to do this + // because some types, like unions, can't be completely represented + // in the LLVM type system.) + if (GV->getType()->getElementType() != Init->getType()) { + llvm::GlobalVariable *OldGV = GV; + + GV = new llvm::GlobalVariable(CGM.getModule(), Init->getType(), + OldGV->isConstant(), + OldGV->getLinkage(), Init, "", + /*InsertBefore*/ OldGV, + D.isThreadSpecified(), + CGM.getContext().getTargetAddressSpace(D.getType())); + GV->setVisibility(OldGV->getVisibility()); + + // Steal the name of the old global + GV->takeName(OldGV); + + // Replace all uses of the old global with the new global + llvm::Constant *NewPtrForOldDecl = + llvm::ConstantExpr::getBitCast(GV, OldGV->getType()); + OldGV->replaceAllUsesWith(NewPtrForOldDecl); + + // Erase the old global, since it is no longer used. + OldGV->eraseFromParent(); + } + + GV->setInitializer(Init); + return GV; +} + +void CodeGenFunction::EmitStaticVarDecl(const VarDecl &D, + llvm::GlobalValue::LinkageTypes Linkage) { + llvm::Value *&DMEntry = LocalDeclMap[&D]; + assert(DMEntry == 0 && "Decl already exists in localdeclmap!"); + + llvm::GlobalVariable *GV = CreateStaticVarDecl(D, ".", Linkage); + + // Store into LocalDeclMap before generating initializer to handle + // circular references. + DMEntry = GV; + + // We can't have a VLA here, but we can have a pointer to a VLA, + // even though that doesn't really make any sense. + // Make sure to evaluate VLA bounds now so that we have them for later. + if (D.getType()->isVariablyModifiedType()) + EmitVLASize(D.getType()); + + // Local static block variables must be treated as globals as they may be + // referenced in their RHS initializer block-literal expresion. + CGM.setStaticLocalDeclAddress(&D, GV); + + // If this value has an initializer, emit it. + if (D.getInit()) + GV = AddInitializerToStaticVarDecl(D, GV); + + GV->setAlignment(getContext().getDeclAlign(&D).getQuantity()); + + // FIXME: Merge attribute handling. + if (const AnnotateAttr *AA = D.getAttr<AnnotateAttr>()) { + SourceManager &SM = CGM.getContext().getSourceManager(); + llvm::Constant *Ann = + CGM.EmitAnnotateAttr(GV, AA, + SM.getInstantiationLineNumber(D.getLocation())); + CGM.AddAnnotation(Ann); + } + + if (const SectionAttr *SA = D.getAttr<SectionAttr>()) + GV->setSection(SA->getName()); + + if (D.hasAttr<UsedAttr>()) + CGM.AddUsedGlobal(GV); + + // We may have to cast the constant because of the initializer + // mismatch above. + // + // FIXME: It is really dangerous to store this in the map; if anyone + // RAUW's the GV uses of this constant will be invalid. + const llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(D.getType()); + const llvm::Type *LPtrTy = + LTy->getPointerTo(CGM.getContext().getTargetAddressSpace(D.getType())); + DMEntry = llvm::ConstantExpr::getBitCast(GV, LPtrTy); + + // Emit global variable debug descriptor for static vars. + CGDebugInfo *DI = getDebugInfo(); + if (DI) { + DI->setLocation(D.getLocation()); + DI->EmitGlobalVariable(static_cast<llvm::GlobalVariable *>(GV), &D); + } +} + +namespace { + struct CallArrayDtor : EHScopeStack::Cleanup { + CallArrayDtor(const CXXDestructorDecl *Dtor, + const ConstantArrayType *Type, + llvm::Value *Loc) + : Dtor(Dtor), Type(Type), Loc(Loc) {} + + const CXXDestructorDecl *Dtor; + const ConstantArrayType *Type; + llvm::Value *Loc; + + void Emit(CodeGenFunction &CGF, bool IsForEH) { + QualType BaseElementTy = CGF.getContext().getBaseElementType(Type); + const llvm::Type *BasePtr = CGF.ConvertType(BaseElementTy); + BasePtr = llvm::PointerType::getUnqual(BasePtr); + llvm::Value *BaseAddrPtr = CGF.Builder.CreateBitCast(Loc, BasePtr); + CGF.EmitCXXAggrDestructorCall(Dtor, Type, BaseAddrPtr); + } + }; + + struct CallVarDtor : EHScopeStack::Cleanup { + CallVarDtor(const CXXDestructorDecl *Dtor, + llvm::Value *NRVOFlag, + llvm::Value *Loc) + : Dtor(Dtor), NRVOFlag(NRVOFlag), Loc(Loc) {} + + const CXXDestructorDecl *Dtor; + llvm::Value *NRVOFlag; + llvm::Value *Loc; + + void Emit(CodeGenFunction &CGF, bool IsForEH) { + // Along the exceptions path we always execute the dtor. + bool NRVO = !IsForEH && NRVOFlag; + + llvm::BasicBlock *SkipDtorBB = 0; + if (NRVO) { + // If we exited via NRVO, we skip the destructor call. + llvm::BasicBlock *RunDtorBB = CGF.createBasicBlock("nrvo.unused"); + SkipDtorBB = CGF.createBasicBlock("nrvo.skipdtor"); + llvm::Value *DidNRVO = CGF.Builder.CreateLoad(NRVOFlag, "nrvo.val"); + CGF.Builder.CreateCondBr(DidNRVO, SkipDtorBB, RunDtorBB); + CGF.EmitBlock(RunDtorBB); + } + + CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, + /*ForVirtualBase=*/false, Loc); + + if (NRVO) CGF.EmitBlock(SkipDtorBB); + } + }; +} + +namespace { + struct CallStackRestore : EHScopeStack::Cleanup { + llvm::Value *Stack; + CallStackRestore(llvm::Value *Stack) : Stack(Stack) {} + void Emit(CodeGenFunction &CGF, bool IsForEH) { + llvm::Value *V = CGF.Builder.CreateLoad(Stack, "tmp"); + llvm::Value *F = CGF.CGM.getIntrinsic(llvm::Intrinsic::stackrestore); + CGF.Builder.CreateCall(F, V); + } + }; + + struct CallCleanupFunction : EHScopeStack::Cleanup { + llvm::Constant *CleanupFn; + const CGFunctionInfo &FnInfo; + const VarDecl &Var; + + CallCleanupFunction(llvm::Constant *CleanupFn, const CGFunctionInfo *Info, + const VarDecl *Var) + : CleanupFn(CleanupFn), FnInfo(*Info), Var(*Var) {} + + void Emit(CodeGenFunction &CGF, bool IsForEH) { + DeclRefExpr DRE(const_cast<VarDecl*>(&Var), Var.getType(), VK_LValue, + SourceLocation()); + // Compute the address of the local variable, in case it's a byref + // or something. + llvm::Value *Addr = CGF.EmitDeclRefLValue(&DRE).getAddress(); + + // In some cases, the type of the function argument will be different from + // the type of the pointer. An example of this is + // void f(void* arg); + // __attribute__((cleanup(f))) void *g; + // + // To fix this we insert a bitcast here. + QualType ArgTy = FnInfo.arg_begin()->type; + llvm::Value *Arg = + CGF.Builder.CreateBitCast(Addr, CGF.ConvertType(ArgTy)); + + CallArgList Args; + Args.add(RValue::get(Arg), + CGF.getContext().getPointerType(Var.getType())); + CGF.EmitCall(FnInfo, CleanupFn, ReturnValueSlot(), Args); + } + }; +} + + +/// canEmitInitWithFewStoresAfterMemset - Decide whether we can emit the +/// non-zero parts of the specified initializer with equal or fewer than +/// NumStores scalar stores. +static bool canEmitInitWithFewStoresAfterMemset(llvm::Constant *Init, + unsigned &NumStores) { + // Zero and Undef never requires any extra stores. + if (isa<llvm::ConstantAggregateZero>(Init) || + isa<llvm::ConstantPointerNull>(Init) || + isa<llvm::UndefValue>(Init)) + return true; + if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) || + isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) || + isa<llvm::ConstantExpr>(Init)) + return Init->isNullValue() || NumStores--; + + // See if we can emit each element. + if (isa<llvm::ConstantArray>(Init) || isa<llvm::ConstantStruct>(Init)) { + for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) { + llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i)); + if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores)) + return false; + } + return true; + } + + // Anything else is hard and scary. + return false; +} + +/// emitStoresForInitAfterMemset - For inits that +/// canEmitInitWithFewStoresAfterMemset returned true for, emit the scalar +/// stores that would be required. +static void emitStoresForInitAfterMemset(llvm::Constant *Init, llvm::Value *Loc, + bool isVolatile, CGBuilderTy &Builder) { + // Zero doesn't require any stores. + if (isa<llvm::ConstantAggregateZero>(Init) || + isa<llvm::ConstantPointerNull>(Init) || + isa<llvm::UndefValue>(Init)) + return; + + if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) || + isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) || + isa<llvm::ConstantExpr>(Init)) { + if (!Init->isNullValue()) + Builder.CreateStore(Init, Loc, isVolatile); + return; + } + + assert((isa<llvm::ConstantStruct>(Init) || isa<llvm::ConstantArray>(Init)) && + "Unknown value type!"); + + for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) { + llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i)); + if (Elt->isNullValue()) continue; + + // Otherwise, get a pointer to the element and emit it. + emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i), + isVolatile, Builder); + } +} + + +/// shouldUseMemSetPlusStoresToInitialize - Decide whether we should use memset +/// plus some stores to initialize a local variable instead of using a memcpy +/// from a constant global. It is beneficial to use memset if the global is all +/// zeros, or mostly zeros and large. +static bool shouldUseMemSetPlusStoresToInitialize(llvm::Constant *Init, + uint64_t GlobalSize) { + // If a global is all zeros, always use a memset. + if (isa<llvm::ConstantAggregateZero>(Init)) return true; + + + // If a non-zero global is <= 32 bytes, always use a memcpy. If it is large, + // do it if it will require 6 or fewer scalar stores. + // TODO: Should budget depends on the size? Avoiding a large global warrants + // plopping in more stores. + unsigned StoreBudget = 6; + uint64_t SizeLimit = 32; + + return GlobalSize > SizeLimit && + canEmitInitWithFewStoresAfterMemset(Init, StoreBudget); +} + + +/// EmitAutoVarDecl - Emit code and set up an entry in LocalDeclMap for a +/// variable declaration with auto, register, or no storage class specifier. +/// These turn into simple stack objects, or GlobalValues depending on target. +void CodeGenFunction::EmitAutoVarDecl(const VarDecl &D) { + AutoVarEmission emission = EmitAutoVarAlloca(D); + EmitAutoVarInit(emission); + EmitAutoVarCleanups(emission); +} + +/// EmitAutoVarAlloca - Emit the alloca and debug information for a +/// local variable. Does not emit initalization or destruction. +CodeGenFunction::AutoVarEmission +CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) { + QualType Ty = D.getType(); + + AutoVarEmission emission(D); + + bool isByRef = D.hasAttr<BlocksAttr>(); + emission.IsByRef = isByRef; + + CharUnits alignment = getContext().getDeclAlign(&D); + emission.Alignment = alignment; + + llvm::Value *DeclPtr; + if (Ty->isConstantSizeType()) { + if (!Target.useGlobalsForAutomaticVariables()) { + bool NRVO = getContext().getLangOptions().ElideConstructors && + D.isNRVOVariable(); + + // If this value is a POD array or struct with a statically + // determinable constant initializer, there are optimizations we + // can do. + // TODO: we can potentially constant-evaluate non-POD structs and + // arrays as long as the initialization is trivial (e.g. if they + // have a non-trivial destructor, but not a non-trivial constructor). + if (D.getInit() && + (Ty->isArrayType() || Ty->isRecordType()) && Ty->isPODType() && + D.getInit()->isConstantInitializer(getContext(), false)) { + + // If the variable's a const type, and it's neither an NRVO + // candidate nor a __block variable, emit it as a global instead. + if (CGM.getCodeGenOpts().MergeAllConstants && Ty.isConstQualified() && + !NRVO && !isByRef) { + EmitStaticVarDecl(D, llvm::GlobalValue::InternalLinkage); + + emission.Address = 0; // signal this condition to later callbacks + assert(emission.wasEmittedAsGlobal()); + return emission; + } + + // Otherwise, tell the initialization code that we're in this case. + emission.IsConstantAggregate = true; + } + + // A normal fixed sized variable becomes an alloca in the entry block, + // unless it's an NRVO variable. + const llvm::Type *LTy = ConvertTypeForMem(Ty); + + if (NRVO) { + // The named return value optimization: allocate this variable in the + // return slot, so that we can elide the copy when returning this + // variable (C++0x [class.copy]p34). + DeclPtr = ReturnValue; + + if (const RecordType *RecordTy = Ty->getAs<RecordType>()) { + if (!cast<CXXRecordDecl>(RecordTy->getDecl())->hasTrivialDestructor()) { + // Create a flag that is used to indicate when the NRVO was applied + // to this variable. Set it to zero to indicate that NRVO was not + // applied. + llvm::Value *Zero = Builder.getFalse(); + llvm::Value *NRVOFlag = CreateTempAlloca(Zero->getType(), "nrvo"); + EnsureInsertPoint(); + Builder.CreateStore(Zero, NRVOFlag); + + // Record the NRVO flag for this variable. + NRVOFlags[&D] = NRVOFlag; + emission.NRVOFlag = NRVOFlag; + } + } + } else { + if (isByRef) + LTy = BuildByRefType(&D); + + llvm::AllocaInst *Alloc = CreateTempAlloca(LTy); + Alloc->setName(D.getNameAsString()); + + CharUnits allocaAlignment = alignment; + if (isByRef) + allocaAlignment = std::max(allocaAlignment, + getContext().toCharUnitsFromBits(Target.getPointerAlign(0))); + Alloc->setAlignment(allocaAlignment.getQuantity()); + DeclPtr = Alloc; + } + } else { + // Targets that don't support recursion emit locals as globals. + const char *Class = + D.getStorageClass() == SC_Register ? ".reg." : ".auto."; + DeclPtr = CreateStaticVarDecl(D, Class, + llvm::GlobalValue::InternalLinkage); + } + + // FIXME: Can this happen? + if (Ty->isVariablyModifiedType()) + EmitVLASize(Ty); + } else { + EnsureInsertPoint(); + + if (!DidCallStackSave) { + // Save the stack. + llvm::Value *Stack = CreateTempAlloca(Int8PtrTy, "saved_stack"); + + llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stacksave); + llvm::Value *V = Builder.CreateCall(F); + + Builder.CreateStore(V, Stack); + + DidCallStackSave = true; + + // Push a cleanup block and restore the stack there. + // FIXME: in general circumstances, this should be an EH cleanup. + EHStack.pushCleanup<CallStackRestore>(NormalCleanup, Stack); + } + + // Get the element type. + const llvm::Type *LElemTy = ConvertTypeForMem(Ty); + const llvm::Type *LElemPtrTy = + LElemTy->getPointerTo(CGM.getContext().getTargetAddressSpace(Ty)); + + llvm::Value *VLASize = EmitVLASize(Ty); + + // Allocate memory for the array. + llvm::AllocaInst *VLA = + Builder.CreateAlloca(llvm::Type::getInt8Ty(getLLVMContext()), VLASize, "vla"); + VLA->setAlignment(alignment.getQuantity()); + + DeclPtr = Builder.CreateBitCast(VLA, LElemPtrTy, "tmp"); + } + + llvm::Value *&DMEntry = LocalDeclMap[&D]; + assert(DMEntry == 0 && "Decl already exists in localdeclmap!"); + DMEntry = DeclPtr; + emission.Address = DeclPtr; + + // Emit debug info for local var declaration. + if (CGDebugInfo *DI = getDebugInfo()) { + assert(HaveInsertPoint() && "Unexpected unreachable point!"); + + DI->setLocation(D.getLocation()); + if (Target.useGlobalsForAutomaticVariables()) { + DI->EmitGlobalVariable(static_cast<llvm::GlobalVariable *>(DeclPtr), &D); + } else + DI->EmitDeclareOfAutoVariable(&D, DeclPtr, Builder); + } + + return emission; +} + +/// Determines whether the given __block variable is potentially +/// captured by the given expression. +static bool isCapturedBy(const VarDecl &var, const Expr *e) { + // Skip the most common kinds of expressions that make + // hierarchy-walking expensive. + e = e->IgnoreParenCasts(); + + if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) { + const BlockDecl *block = be->getBlockDecl(); + for (BlockDecl::capture_const_iterator i = block->capture_begin(), + e = block->capture_end(); i != e; ++i) { + if (i->getVariable() == &var) + return true; + } + + // No need to walk into the subexpressions. + return false; + } + + for (Stmt::const_child_range children = e->children(); children; ++children) + if (isCapturedBy(var, cast<Expr>(*children))) + return true; + + return false; +} + +void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) { + assert(emission.Variable && "emission was not valid!"); + + // If this was emitted as a global constant, we're done. + if (emission.wasEmittedAsGlobal()) return; + + const VarDecl &D = *emission.Variable; + QualType type = D.getType(); + + // If this local has an initializer, emit it now. + const Expr *Init = D.getInit(); + + // If we are at an unreachable point, we don't need to emit the initializer + // unless it contains a label. + if (!HaveInsertPoint()) { + if (!Init || !ContainsLabel(Init)) return; + EnsureInsertPoint(); + } + + // Initialize the structure of a __block variable. + if (emission.IsByRef) + emitByrefStructureInit(emission); + + if (!Init) return; + + CharUnits alignment = emission.Alignment; + + // Check whether this is a byref variable that's potentially + // captured and moved by its own initializer. If so, we'll need to + // emit the initializer first, then copy into the variable. + bool capturedByInit = emission.IsByRef && isCapturedBy(D, Init); + + llvm::Value *Loc = + capturedByInit ? emission.Address : emission.getObjectAddress(*this); + + if (!emission.IsConstantAggregate) + return EmitExprAsInit(Init, &D, Loc, alignment, capturedByInit); + + // If this is a simple aggregate initialization, we can optimize it + // in various ways. + assert(!capturedByInit && "constant init contains a capturing block?"); + + bool isVolatile = type.isVolatileQualified(); + + llvm::Constant *constant = CGM.EmitConstantExpr(D.getInit(), type, this); + assert(constant != 0 && "Wasn't a simple constant init?"); + + llvm::Value *SizeVal = + llvm::ConstantInt::get(IntPtrTy, + getContext().getTypeSizeInChars(type).getQuantity()); + + const llvm::Type *BP = Int8PtrTy; + if (Loc->getType() != BP) + Loc = Builder.CreateBitCast(Loc, BP, "tmp"); + + // If the initializer is all or mostly zeros, codegen with memset then do + // a few stores afterward. + if (shouldUseMemSetPlusStoresToInitialize(constant, + CGM.getTargetData().getTypeAllocSize(constant->getType()))) { + Builder.CreateMemSet(Loc, llvm::ConstantInt::get(Int8Ty, 0), SizeVal, + alignment.getQuantity(), isVolatile); + if (!constant->isNullValue()) { + Loc = Builder.CreateBitCast(Loc, constant->getType()->getPointerTo()); + emitStoresForInitAfterMemset(constant, Loc, isVolatile, Builder); + } + } else { + // Otherwise, create a temporary global with the initializer then + // memcpy from the global to the alloca. + std::string Name = GetStaticDeclName(*this, D, "."); + llvm::GlobalVariable *GV = + new llvm::GlobalVariable(CGM.getModule(), constant->getType(), true, + llvm::GlobalValue::InternalLinkage, + constant, Name, 0, false, 0); + GV->setAlignment(alignment.getQuantity()); + + llvm::Value *SrcPtr = GV; + if (SrcPtr->getType() != BP) + SrcPtr = Builder.CreateBitCast(SrcPtr, BP, "tmp"); + + Builder.CreateMemCpy(Loc, SrcPtr, SizeVal, alignment.getQuantity(), + isVolatile); + } +} + +/// Emit an expression as an initializer for a variable at the given +/// location. The expression is not necessarily the normal +/// initializer for the variable, and the address is not necessarily +/// its normal location. +/// +/// \param init the initializing expression +/// \param var the variable to act as if we're initializing +/// \param loc the address to initialize; its type is a pointer +/// to the LLVM mapping of the variable's type +/// \param alignment the alignment of the address +/// \param capturedByInit true if the variable is a __block variable +/// whose address is potentially changed by the initializer +void CodeGenFunction::EmitExprAsInit(const Expr *init, + const VarDecl *var, + llvm::Value *loc, + CharUnits alignment, + bool capturedByInit) { + QualType type = var->getType(); + bool isVolatile = type.isVolatileQualified(); + + if (type->isReferenceType()) { + RValue RV = EmitReferenceBindingToExpr(init, var); + if (capturedByInit) loc = BuildBlockByrefAddress(loc, var); + EmitStoreOfScalar(RV.getScalarVal(), loc, false, + alignment.getQuantity(), type); + } else if (!hasAggregateLLVMType(type)) { + llvm::Value *V = EmitScalarExpr(init); + if (capturedByInit) loc = BuildBlockByrefAddress(loc, var); + EmitStoreOfScalar(V, loc, isVolatile, alignment.getQuantity(), type); + } else if (type->isAnyComplexType()) { + ComplexPairTy complex = EmitComplexExpr(init); + if (capturedByInit) loc = BuildBlockByrefAddress(loc, var); + StoreComplexToAddr(complex, loc, isVolatile); + } else { + // TODO: how can we delay here if D is captured by its initializer? + EmitAggExpr(init, AggValueSlot::forAddr(loc, isVolatile, true, false)); + } +} + +void CodeGenFunction::EmitAutoVarCleanups(const AutoVarEmission &emission) { + assert(emission.Variable && "emission was not valid!"); + + // If this was emitted as a global constant, we're done. + if (emission.wasEmittedAsGlobal()) return; + + const VarDecl &D = *emission.Variable; + + // Handle C++ destruction of variables. + if (getLangOptions().CPlusPlus) { + QualType type = D.getType(); + QualType baseType = getContext().getBaseElementType(type); + if (const RecordType *RT = baseType->getAs<RecordType>()) { + CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl()); + if (!ClassDecl->hasTrivialDestructor()) { + // Note: We suppress the destructor call when the corresponding NRVO + // flag has been set. + + // Note that for __block variables, we want to destroy the + // original stack object, not the possible forwarded object. + llvm::Value *Loc = emission.getObjectAddress(*this); + + const CXXDestructorDecl *D = ClassDecl->getDestructor(); + assert(D && "EmitLocalBlockVarDecl - destructor is nul"); + + if (type != baseType) { + const ConstantArrayType *Array = + getContext().getAsConstantArrayType(type); + assert(Array && "types changed without array?"); + EHStack.pushCleanup<CallArrayDtor>(NormalAndEHCleanup, + D, Array, Loc); + } else { + EHStack.pushCleanup<CallVarDtor>(NormalAndEHCleanup, + D, emission.NRVOFlag, Loc); + } + } + } + } + + // Handle the cleanup attribute. + if (const CleanupAttr *CA = D.getAttr<CleanupAttr>()) { + const FunctionDecl *FD = CA->getFunctionDecl(); + + llvm::Constant *F = CGM.GetAddrOfFunction(FD); + assert(F && "Could not find function!"); + + const CGFunctionInfo &Info = CGM.getTypes().getFunctionInfo(FD); + EHStack.pushCleanup<CallCleanupFunction>(NormalAndEHCleanup, F, &Info, &D); + } + + // If this is a block variable, call _Block_object_destroy + // (on the unforwarded address). + if (emission.IsByRef) + enterByrefCleanup(emission); +} + +/// Emit an alloca (or GlobalValue depending on target) +/// for the specified parameter and set up LocalDeclMap. +void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg, + unsigned ArgNo) { + // FIXME: Why isn't ImplicitParamDecl a ParmVarDecl? + assert((isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)) && + "Invalid argument to EmitParmDecl"); + + Arg->setName(D.getName()); + + // Use better IR generation for certain implicit parameters. + if (isa<ImplicitParamDecl>(D)) { + // The only implicit argument a block has is its literal. + if (BlockInfo) { + LocalDeclMap[&D] = Arg; + + if (CGDebugInfo *DI = getDebugInfo()) { + DI->setLocation(D.getLocation()); + DI->EmitDeclareOfBlockLiteralArgVariable(*BlockInfo, Arg, Builder); + } + + return; + } + } + + QualType Ty = D.getType(); + + llvm::Value *DeclPtr; + // If this is an aggregate or variable sized value, reuse the input pointer. + if (!Ty->isConstantSizeType() || + CodeGenFunction::hasAggregateLLVMType(Ty)) { + DeclPtr = Arg; + } else { + // Otherwise, create a temporary to hold the value. + DeclPtr = CreateMemTemp(Ty, D.getName() + ".addr"); + + // Store the initial value into the alloca. + EmitStoreOfScalar(Arg, DeclPtr, Ty.isVolatileQualified(), + getContext().getDeclAlign(&D).getQuantity(), Ty, + CGM.getTBAAInfo(Ty)); + } + + llvm::Value *&DMEntry = LocalDeclMap[&D]; + assert(DMEntry == 0 && "Decl already exists in localdeclmap!"); + DMEntry = DeclPtr; + + // Emit debug info for param declaration. + if (CGDebugInfo *DI = getDebugInfo()) { + DI->setLocation(D.getLocation()); + DI->EmitDeclareOfArgVariable(&D, DeclPtr, ArgNo, Builder); + } +} |
