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clang-1/lib/CodeGen/CGDecl.cpp

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//===--- 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 "CGBlocks.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:
case Decl::Label:
assert(0 && "Declaration not 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]
// 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;
const TypedefDecl &TD = cast<TypedefDecl>(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(), Ty.getAddressSpace());
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(),
D.getType().getAddressSpace());
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(D.getType().getAddressSpace());
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);
}
}
unsigned CodeGenFunction::getByRefValueLLVMField(const ValueDecl *VD) const {
assert(ByRefValueInfo.count(VD) && "Did not find value!");
return ByRefValueInfo.find(VD)->second.second;
}
llvm::Value *CodeGenFunction::BuildBlockByrefAddress(llvm::Value *BaseAddr,
const VarDecl *V) {
llvm::Value *Loc = Builder.CreateStructGEP(BaseAddr, 1, "forwarding");
Loc = Builder.CreateLoad(Loc);
Loc = Builder.CreateStructGEP(Loc, getByRefValueLLVMField(V),
V->getNameAsString());
return Loc;
}
/// BuildByRefType - This routine changes a __block variable declared as T x
/// into:
///
/// struct {
/// void *__isa;
/// void *__forwarding;
/// int32_t __flags;
/// int32_t __size;
/// void *__copy_helper; // only if needed
/// void *__destroy_helper; // only if needed
/// char padding[X]; // only if needed
/// T x;
/// } x
///
const llvm::Type *CodeGenFunction::BuildByRefType(const VarDecl *D) {
std::pair<const llvm::Type *, unsigned> &Info = ByRefValueInfo[D];
if (Info.first)
return Info.first;
QualType Ty = D->getType();
std::vector<const llvm::Type *> Types;
llvm::PATypeHolder ByRefTypeHolder = llvm::OpaqueType::get(getLLVMContext());
// void *__isa;
Types.push_back(Int8PtrTy);
// void *__forwarding;
Types.push_back(llvm::PointerType::getUnqual(ByRefTypeHolder));
// int32_t __flags;
Types.push_back(Int32Ty);
// int32_t __size;
Types.push_back(Int32Ty);
bool HasCopyAndDispose = getContext().BlockRequiresCopying(Ty);
if (HasCopyAndDispose) {
/// void *__copy_helper;
Types.push_back(Int8PtrTy);
/// void *__destroy_helper;
Types.push_back(Int8PtrTy);
}
bool Packed = false;
CharUnits Align = getContext().getDeclAlign(D);
if (Align > getContext().toCharUnitsFromBits(Target.getPointerAlign(0))) {
// We have to insert padding.
// The struct above has 2 32-bit integers.
unsigned CurrentOffsetInBytes = 4 * 2;
// And either 2 or 4 pointers.
CurrentOffsetInBytes += (HasCopyAndDispose ? 4 : 2) *
CGM.getTargetData().getTypeAllocSize(Int8PtrTy);
// Align the offset.
unsigned AlignedOffsetInBytes =
llvm::RoundUpToAlignment(CurrentOffsetInBytes, Align.getQuantity());
unsigned NumPaddingBytes = AlignedOffsetInBytes - CurrentOffsetInBytes;
if (NumPaddingBytes > 0) {
const llvm::Type *Ty = llvm::Type::getInt8Ty(getLLVMContext());
// FIXME: We need a sema error for alignment larger than the minimum of
// the maximal stack alignmint and the alignment of malloc on the system.
if (NumPaddingBytes > 1)
Ty = llvm::ArrayType::get(Ty, NumPaddingBytes);
Types.push_back(Ty);
// We want a packed struct.
Packed = true;
}
}
// T x;
Types.push_back(ConvertTypeForMem(Ty));
const llvm::Type *T = llvm::StructType::get(getLLVMContext(), Types, Packed);
cast<llvm::OpaqueType>(ByRefTypeHolder.get())->refineAbstractTypeTo(T);
CGM.getModule().addTypeName("struct.__block_byref_" + D->getNameAsString(),
ByRefTypeHolder.get());
Info.first = ByRefTypeHolder.get();
Info.second = Types.size() - 1;
return Info.first;
}
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;
llvm::Value *Addr;
const VarDecl &Var;
CallCleanupFunction(llvm::Constant *CleanupFn, const CGFunctionInfo *Info,
llvm::Value *Addr, const VarDecl *Var)
: CleanupFn(CleanupFn), FnInfo(*Info), Addr(Addr), Var(*Var) {}
void Emit(CodeGenFunction &CGF, bool IsForEH) {
// 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.push_back(std::make_pair(RValue::get(Arg),
CGF.getContext().getPointerType(Var.getType())));
CGF.EmitCall(FnInfo, CleanupFn, ReturnValueSlot(), Args);
}
};
struct CallBlockRelease : EHScopeStack::Cleanup {
llvm::Value *Addr;
CallBlockRelease(llvm::Value *Addr) : Addr(Addr) {}
void Emit(CodeGenFunction &CGF, bool IsForEH) {
llvm::Value *V = CGF.Builder.CreateStructGEP(Addr, 1, "forwarding");
V = CGF.Builder.CreateLoad(V);
CGF.BuildBlockRelease(V, BLOCK_FIELD_IS_BYREF);
}
};
}
/// 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,
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);
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),
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,
SpecialInitFn *SpecialInit) {
QualType Ty = D.getType();
unsigned Alignment = getContext().getDeclAlign(&D).getQuantity();
bool isByRef = D.hasAttr<BlocksAttr>();
bool needsDispose = false;
CharUnits Align = CharUnits::Zero();
bool IsSimpleConstantInitializer = false;
bool NRVO = false;
llvm::Value *NRVOFlag = 0;
llvm::Value *DeclPtr;
if (Ty->isConstantSizeType()) {
if (!Target.useGlobalsForAutomaticVariables()) {
NRVO = getContext().getLangOptions().ElideConstructors &&
D.isNRVOVariable();
// If this value is an array or struct, is POD, and if the initializer is
// a staticly determinable constant, try to optimize it (unless the NRVO
// is already optimizing this).
if (!NRVO && D.getInit() && !isByRef &&
(Ty->isArrayType() || Ty->isRecordType()) &&
Ty->isPODType() &&
D.getInit()->isConstantInitializer(getContext(), false)) {
// If this variable is marked 'const', emit the value as a global.
if (CGM.getCodeGenOpts().MergeAllConstants &&
Ty.isConstant(getContext())) {
EmitStaticVarDecl(D, llvm::GlobalValue::InternalLinkage);
return;
}
IsSimpleConstantInitializer = 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();
NRVOFlag = CreateTempAlloca(Zero->getType(), "nrvo");
EnsureInsertPoint();
Builder.CreateStore(Zero, NRVOFlag);
// Record the NRVO flag for this variable.
NRVOFlags[&D] = NRVOFlag;
}
}
} else {
if (isByRef)
LTy = BuildByRefType(&D);
llvm::AllocaInst *Alloc = CreateTempAlloca(LTy);
Alloc->setName(D.getNameAsString());
Align = getContext().getDeclAlign(&D);
if (isByRef)
Align = std::max(Align,
getContext().toCharUnitsFromBits(Target.getPointerAlign(0)));
Alloc->setAlignment(Align.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(Ty.getAddressSpace());
llvm::Value *VLASize = EmitVLASize(Ty);
// Allocate memory for the array.
llvm::AllocaInst *VLA =
Builder.CreateAlloca(llvm::Type::getInt8Ty(getLLVMContext()), VLASize, "vla");
VLA->setAlignment(getContext().getDeclAlign(&D).getQuantity());
DeclPtr = Builder.CreateBitCast(VLA, LElemPtrTy, "tmp");
}
llvm::Value *&DMEntry = LocalDeclMap[&D];
assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
DMEntry = 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);
}
// 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 (!ContainsLabel(Init))
Init = 0;
else
EnsureInsertPoint();
}
if (isByRef) {
EnsureInsertPoint();
llvm::Value *isa_field = Builder.CreateStructGEP(DeclPtr, 0);
llvm::Value *forwarding_field = Builder.CreateStructGEP(DeclPtr, 1);
llvm::Value *flags_field = Builder.CreateStructGEP(DeclPtr, 2);
llvm::Value *size_field = Builder.CreateStructGEP(DeclPtr, 3);
llvm::Value *V;
BlockFieldFlags fieldFlags;
bool fieldNeedsCopyDispose = false;
needsDispose = true;
if (Ty->isBlockPointerType()) {
fieldFlags |= BLOCK_FIELD_IS_BLOCK;
fieldNeedsCopyDispose = true;
} else if (getContext().isObjCNSObjectType(Ty) ||
Ty->isObjCObjectPointerType()) {
fieldFlags |= BLOCK_FIELD_IS_OBJECT;
fieldNeedsCopyDispose = true;
} else if (getLangOptions().CPlusPlus) {
if (getContext().getBlockVarCopyInits(&D))
fieldNeedsCopyDispose = true;
else if (const CXXRecordDecl *record = D.getType()->getAsCXXRecordDecl())
fieldNeedsCopyDispose = !record->hasTrivialDestructor();
}
// FIXME: Someone double check this.
if (Ty.isObjCGCWeak())
fieldFlags |= BLOCK_FIELD_IS_WEAK;
int isa = 0;
if (fieldFlags & BLOCK_FIELD_IS_WEAK)
isa = 1;
V = Builder.CreateIntToPtr(Builder.getInt32(isa), Int8PtrTy, "isa");
Builder.CreateStore(V, isa_field);
Builder.CreateStore(DeclPtr, forwarding_field);
Builder.CreateStore(Builder.getInt32(fieldFlags.getBitMask()), flags_field);
const llvm::Type *V1;
V1 = cast<llvm::PointerType>(DeclPtr->getType())->getElementType();
V = Builder.getInt32(CGM.GetTargetTypeStoreSize(V1).getQuantity());
Builder.CreateStore(V, size_field);
if (fieldNeedsCopyDispose) {
llvm::Value *copy_helper = Builder.CreateStructGEP(DeclPtr, 4);
Builder.CreateStore(CGM.BuildbyrefCopyHelper(DeclPtr->getType(),
fieldFlags,
Align.getQuantity(), &D),
copy_helper);
llvm::Value *destroy_helper = Builder.CreateStructGEP(DeclPtr, 5);
Builder.CreateStore(CGM.BuildbyrefDestroyHelper(DeclPtr->getType(),
fieldFlags,
Align.getQuantity(), &D),
destroy_helper);
}
}
if (SpecialInit) {
SpecialInit(*this, D, DeclPtr);
} else if (Init) {
llvm::Value *Loc = DeclPtr;
bool isVolatile = getContext().getCanonicalType(Ty).isVolatileQualified();
// If the initializer was a simple constant initializer, we can optimize it
// in various ways.
if (IsSimpleConstantInitializer) {
llvm::Constant *Init = CGM.EmitConstantExpr(D.getInit(), Ty,this);
assert(Init != 0 && "Wasn't a simple constant init?");
llvm::Value *SizeVal =
llvm::ConstantInt::get(IntPtrTy,
getContext().getTypeSizeInChars(Ty).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(Init,
CGM.getTargetData().getTypeAllocSize(Init->getType()))) {
Builder.CreateMemSet(Loc, Builder.getInt8(0), SizeVal,
Align.getQuantity(), false);
if (!Init->isNullValue()) {
Loc = Builder.CreateBitCast(Loc, Init->getType()->getPointerTo());
emitStoresForInitAfterMemset(Init, Loc, 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(), Init->getType(), true,
llvm::GlobalValue::InternalLinkage,
Init, Name, 0, false, 0);
GV->setAlignment(Align.getQuantity());
llvm::Value *SrcPtr = GV;
if (SrcPtr->getType() != BP)
SrcPtr = Builder.CreateBitCast(SrcPtr, BP, "tmp");
Builder.CreateMemCpy(Loc, SrcPtr, SizeVal, Align.getQuantity(), false);
}
} else if (Ty->isReferenceType()) {
RValue RV = EmitReferenceBindingToExpr(Init, &D);
if (isByRef)
Loc = Builder.CreateStructGEP(DeclPtr, getByRefValueLLVMField(&D),
D.getNameAsString());
EmitStoreOfScalar(RV.getScalarVal(), Loc, false, Alignment, Ty);
} else if (!hasAggregateLLVMType(Init->getType())) {
llvm::Value *V = EmitScalarExpr(Init);
if (isByRef) {
// When RHS has side-effect, must go through "forwarding' field
// to get to the address of the __block variable descriptor.
if (Init->HasSideEffects(getContext()))
Loc = BuildBlockByrefAddress(DeclPtr, &D);
else
Loc = Builder.CreateStructGEP(DeclPtr, getByRefValueLLVMField(&D),
D.getNameAsString());
}
EmitStoreOfScalar(V, Loc, isVolatile, Alignment, Ty);
} else if (Init->getType()->isAnyComplexType()) {
if (isByRef)
Loc = Builder.CreateStructGEP(DeclPtr, getByRefValueLLVMField(&D),
D.getNameAsString());
EmitComplexExprIntoAddr(Init, Loc, isVolatile);
} else {
if (isByRef)
Loc = Builder.CreateStructGEP(DeclPtr, getByRefValueLLVMField(&D),
D.getNameAsString());
EmitAggExpr(Init, AggValueSlot::forAddr(Loc, isVolatile, true, false));
}
}
// Handle CXX destruction of variables.
QualType DtorTy(Ty);
while (const ArrayType *Array = getContext().getAsArrayType(DtorTy))
DtorTy = getContext().getBaseElementType(Array);
if (const RecordType *RT = DtorTy->getAs<RecordType>())
if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
if (!ClassDecl->hasTrivialDestructor()) {
// Note: We suppress the destructor call when the corresponding NRVO
// flag has been set.
llvm::Value *Loc = DeclPtr;
if (isByRef)
Loc = Builder.CreateStructGEP(DeclPtr, getByRefValueLLVMField(&D),
D.getNameAsString());
const CXXDestructorDecl *D = ClassDecl->getDestructor();
assert(D && "EmitLocalBlockVarDecl - destructor is nul");
if (const ConstantArrayType *Array =
getContext().getAsConstantArrayType(Ty)) {
EHStack.pushCleanup<CallArrayDtor>(NormalAndEHCleanup,
D, Array, Loc);
} else {
EHStack.pushCleanup<CallVarDtor>(NormalAndEHCleanup,
D, 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, DeclPtr, &D);
}
// If this is a block variable, clean it up.
if (needsDispose && CGM.getLangOptions().getGCMode() != LangOptions::GCOnly)
EHStack.pushCleanup<CallBlockRelease>(NormalAndEHCleanup, DeclPtr);
}
/// 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) {
// FIXME: Why isn't ImplicitParamDecl a ParmVarDecl?
assert((isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)) &&
"Invalid argument to EmitParmDecl");
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));
}
Arg->setName(D.getName());
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, Builder);
}
}
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