llvm-project/clang/lib/CodeGen/CGExprAgg.cpp
John McCall cf14216509 Store inheritance paths after CastExprs instead of inside them.
This takes some trickery since CastExpr has subclasses (and indeed,
is abstract).

Also, smoosh the CastKind into the bitfield from Expr.

Drops two words of storage from Expr in the common case of expressions
which don't need inheritance paths.  Avoids a separate allocation and
another word of overhead in cases needing inheritance paths.  Also has
the advantage of not leaking memory, since destructors for AST nodes are
never run.

llvm-svn: 110507
2010-08-07 06:22:56 +00:00

876 lines
33 KiB
C++

//===--- CGExprAgg.cpp - Emit LLVM Code from Aggregate Expressions --------===//
//
// 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 Aggregate Expr nodes as LLVM code.
//
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "CGObjCRuntime.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/StmtVisitor.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Intrinsics.h"
using namespace clang;
using namespace CodeGen;
//===----------------------------------------------------------------------===//
// Aggregate Expression Emitter
//===----------------------------------------------------------------------===//
namespace {
class AggExprEmitter : public StmtVisitor<AggExprEmitter> {
CodeGenFunction &CGF;
CGBuilderTy &Builder;
llvm::Value *DestPtr;
bool VolatileDest;
bool IgnoreResult;
bool IsInitializer;
bool RequiresGCollection;
ReturnValueSlot getReturnValueSlot() const {
// If the destination slot requires garbage collection, we can't
// use the real return value slot, because we have to use the GC
// API.
if (RequiresGCollection) return ReturnValueSlot();
return ReturnValueSlot(DestPtr, VolatileDest);
}
public:
AggExprEmitter(CodeGenFunction &cgf, llvm::Value *destPtr, bool v,
bool ignore, bool isinit, bool requiresGCollection)
: CGF(cgf), Builder(CGF.Builder),
DestPtr(destPtr), VolatileDest(v), IgnoreResult(ignore),
IsInitializer(isinit), RequiresGCollection(requiresGCollection) {
}
//===--------------------------------------------------------------------===//
// Utilities
//===--------------------------------------------------------------------===//
/// EmitAggLoadOfLValue - Given an expression with aggregate type that
/// represents a value lvalue, this method emits the address of the lvalue,
/// then loads the result into DestPtr.
void EmitAggLoadOfLValue(const Expr *E);
/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
void EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore = false);
void EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore = false);
void EmitGCMove(const Expr *E, RValue Src);
bool TypeRequiresGCollection(QualType T);
//===--------------------------------------------------------------------===//
// Visitor Methods
//===--------------------------------------------------------------------===//
void VisitStmt(Stmt *S) {
CGF.ErrorUnsupported(S, "aggregate expression");
}
void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); }
void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); }
// l-values.
void VisitDeclRefExpr(DeclRefExpr *DRE) { EmitAggLoadOfLValue(DRE); }
void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); }
void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); }
void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); }
void VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
EmitAggLoadOfLValue(E);
}
void VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
EmitAggLoadOfLValue(E);
}
void VisitBlockDeclRefExpr(const BlockDeclRefExpr *E) {
EmitAggLoadOfLValue(E);
}
void VisitPredefinedExpr(const PredefinedExpr *E) {
EmitAggLoadOfLValue(E);
}
// Operators.
void VisitCastExpr(CastExpr *E);
void VisitCallExpr(const CallExpr *E);
void VisitStmtExpr(const StmtExpr *E);
void VisitBinaryOperator(const BinaryOperator *BO);
void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO);
void VisitBinAssign(const BinaryOperator *E);
void VisitBinComma(const BinaryOperator *E);
void VisitUnaryAddrOf(const UnaryOperator *E);
void VisitObjCMessageExpr(ObjCMessageExpr *E);
void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
EmitAggLoadOfLValue(E);
}
void VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E);
void VisitObjCImplicitSetterGetterRefExpr(ObjCImplicitSetterGetterRefExpr *E);
void VisitConditionalOperator(const ConditionalOperator *CO);
void VisitChooseExpr(const ChooseExpr *CE);
void VisitInitListExpr(InitListExpr *E);
void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
Visit(DAE->getExpr());
}
void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E);
void VisitCXXConstructExpr(const CXXConstructExpr *E);
void VisitCXXExprWithTemporaries(CXXExprWithTemporaries *E);
void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E);
void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); }
void VisitVAArgExpr(VAArgExpr *E);
void EmitInitializationToLValue(Expr *E, LValue Address, QualType T);
void EmitNullInitializationToLValue(LValue Address, QualType T);
// case Expr::ChooseExprClass:
void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); }
};
} // end anonymous namespace.
//===----------------------------------------------------------------------===//
// Utilities
//===----------------------------------------------------------------------===//
/// EmitAggLoadOfLValue - Given an expression with aggregate type that
/// represents a value lvalue, this method emits the address of the lvalue,
/// then loads the result into DestPtr.
void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
LValue LV = CGF.EmitLValue(E);
EmitFinalDestCopy(E, LV);
}
/// \brief True if the given aggregate type requires special GC API calls.
bool AggExprEmitter::TypeRequiresGCollection(QualType T) {
// Only record types have members that might require garbage collection.
const RecordType *RecordTy = T->getAs<RecordType>();
if (!RecordTy) return false;
// Don't mess with non-trivial C++ types.
RecordDecl *Record = RecordTy->getDecl();
if (isa<CXXRecordDecl>(Record) &&
(!cast<CXXRecordDecl>(Record)->hasTrivialCopyConstructor() ||
!cast<CXXRecordDecl>(Record)->hasTrivialDestructor()))
return false;
// Check whether the type has an object member.
return Record->hasObjectMember();
}
/// \brief Perform the final move to DestPtr if RequiresGCollection is set.
///
/// The idea is that you do something like this:
/// RValue Result = EmitSomething(..., getReturnValueSlot());
/// EmitGCMove(E, Result);
/// If GC doesn't interfere, this will cause the result to be emitted
/// directly into the return value slot. If GC does interfere, a final
/// move will be performed.
void AggExprEmitter::EmitGCMove(const Expr *E, RValue Src) {
if (RequiresGCollection) {
std::pair<uint64_t, unsigned> TypeInfo =
CGF.getContext().getTypeInfo(E->getType());
unsigned long size = TypeInfo.first/8;
const llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType());
llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size);
CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF, DestPtr,
Src.getAggregateAddr(),
SizeVal);
}
}
/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
void AggExprEmitter::EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore) {
assert(Src.isAggregate() && "value must be aggregate value!");
// If the result is ignored, don't copy from the value.
if (DestPtr == 0) {
if (!Src.isVolatileQualified() || (IgnoreResult && Ignore))
return;
// If the source is volatile, we must read from it; to do that, we need
// some place to put it.
DestPtr = CGF.CreateMemTemp(E->getType(), "agg.tmp");
}
if (RequiresGCollection) {
std::pair<uint64_t, unsigned> TypeInfo =
CGF.getContext().getTypeInfo(E->getType());
unsigned long size = TypeInfo.first/8;
const llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType());
llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size);
CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF,
DestPtr, Src.getAggregateAddr(),
SizeVal);
return;
}
// If the result of the assignment is used, copy the LHS there also.
// FIXME: Pass VolatileDest as well. I think we also need to merge volatile
// from the source as well, as we can't eliminate it if either operand
// is volatile, unless copy has volatile for both source and destination..
CGF.EmitAggregateCopy(DestPtr, Src.getAggregateAddr(), E->getType(),
VolatileDest|Src.isVolatileQualified());
}
/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired.
void AggExprEmitter::EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore) {
assert(Src.isSimple() && "Can't have aggregate bitfield, vector, etc");
EmitFinalDestCopy(E, RValue::getAggregate(Src.getAddress(),
Src.isVolatileQualified()),
Ignore);
}
//===----------------------------------------------------------------------===//
// Visitor Methods
//===----------------------------------------------------------------------===//
void AggExprEmitter::VisitCastExpr(CastExpr *E) {
if (!DestPtr && E->getCastKind() != CastExpr::CK_Dynamic) {
Visit(E->getSubExpr());
return;
}
switch (E->getCastKind()) {
default: assert(0 && "Unhandled cast kind!");
case CastExpr::CK_Dynamic: {
assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?");
LValue LV = CGF.EmitCheckedLValue(E->getSubExpr());
// FIXME: Do we also need to handle property references here?
if (LV.isSimple())
CGF.EmitDynamicCast(LV.getAddress(), cast<CXXDynamicCastExpr>(E));
else
CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast");
if (DestPtr)
CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination");
break;
}
case CastExpr::CK_ToUnion: {
// GCC union extension
QualType PtrTy =
CGF.getContext().getPointerType(E->getSubExpr()->getType());
llvm::Value *CastPtr = Builder.CreateBitCast(DestPtr,
CGF.ConvertType(PtrTy));
EmitInitializationToLValue(E->getSubExpr(),
LValue::MakeAddr(CastPtr, Qualifiers()),
E->getSubExpr()->getType());
break;
}
case CastExpr::CK_DerivedToBase:
case CastExpr::CK_BaseToDerived:
case CastExpr::CK_UncheckedDerivedToBase: {
assert(0 && "cannot perform hierarchy conversion in EmitAggExpr: "
"should have been unpacked before we got here");
break;
}
// FIXME: Remove the CK_Unknown check here.
case CastExpr::CK_Unknown:
case CastExpr::CK_NoOp:
case CastExpr::CK_UserDefinedConversion:
case CastExpr::CK_ConstructorConversion:
assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(),
E->getType()) &&
"Implicit cast types must be compatible");
Visit(E->getSubExpr());
break;
case CastExpr::CK_NullToMemberPointer: {
// If the subexpression's type is the C++0x nullptr_t, emit the
// subexpression, which may have side effects.
if (E->getSubExpr()->getType()->isNullPtrType())
Visit(E->getSubExpr());
const llvm::Type *PtrDiffTy =
CGF.ConvertType(CGF.getContext().getPointerDiffType());
llvm::Value *NullValue = llvm::Constant::getNullValue(PtrDiffTy);
llvm::Value *Ptr = Builder.CreateStructGEP(DestPtr, 0, "ptr");
Builder.CreateStore(NullValue, Ptr, VolatileDest);
llvm::Value *Adj = Builder.CreateStructGEP(DestPtr, 1, "adj");
Builder.CreateStore(NullValue, Adj, VolatileDest);
break;
}
case CastExpr::CK_LValueBitCast:
llvm_unreachable("there are no lvalue bit-casts on aggregates");
break;
case CastExpr::CK_BitCast: {
// This must be a member function pointer cast.
Visit(E->getSubExpr());
break;
}
case CastExpr::CK_DerivedToBaseMemberPointer:
case CastExpr::CK_BaseToDerivedMemberPointer: {
QualType SrcType = E->getSubExpr()->getType();
llvm::Value *Src = CGF.CreateMemTemp(SrcType, "tmp");
CGF.EmitAggExpr(E->getSubExpr(), Src, SrcType.isVolatileQualified());
llvm::Value *SrcPtr = Builder.CreateStructGEP(Src, 0, "src.ptr");
SrcPtr = Builder.CreateLoad(SrcPtr);
llvm::Value *SrcAdj = Builder.CreateStructGEP(Src, 1, "src.adj");
SrcAdj = Builder.CreateLoad(SrcAdj);
llvm::Value *DstPtr = Builder.CreateStructGEP(DestPtr, 0, "dst.ptr");
Builder.CreateStore(SrcPtr, DstPtr, VolatileDest);
llvm::Value *DstAdj = Builder.CreateStructGEP(DestPtr, 1, "dst.adj");
// Now See if we need to update the adjustment.
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(SrcType->getAs<MemberPointerType>()->
getClass()->getAs<RecordType>()->getDecl());
const CXXRecordDecl *DerivedDecl =
cast<CXXRecordDecl>(E->getType()->getAs<MemberPointerType>()->
getClass()->getAs<RecordType>()->getDecl());
if (E->getCastKind() == CastExpr::CK_DerivedToBaseMemberPointer)
std::swap(DerivedDecl, BaseDecl);
if (llvm::Constant *Adj =
CGF.CGM.GetNonVirtualBaseClassOffset(DerivedDecl,
E->path_begin(),
E->path_end())) {
if (E->getCastKind() == CastExpr::CK_DerivedToBaseMemberPointer)
SrcAdj = Builder.CreateSub(SrcAdj, Adj, "adj");
else
SrcAdj = Builder.CreateAdd(SrcAdj, Adj, "adj");
}
Builder.CreateStore(SrcAdj, DstAdj, VolatileDest);
break;
}
}
}
void AggExprEmitter::VisitCallExpr(const CallExpr *E) {
if (E->getCallReturnType()->isReferenceType()) {
EmitAggLoadOfLValue(E);
return;
}
RValue RV = CGF.EmitCallExpr(E, getReturnValueSlot());
EmitGCMove(E, RV);
}
void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) {
RValue RV = CGF.EmitObjCMessageExpr(E, getReturnValueSlot());
EmitGCMove(E, RV);
}
void AggExprEmitter::VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E) {
RValue RV = CGF.EmitObjCPropertyGet(E, getReturnValueSlot());
EmitGCMove(E, RV);
}
void AggExprEmitter::VisitObjCImplicitSetterGetterRefExpr(
ObjCImplicitSetterGetterRefExpr *E) {
RValue RV = CGF.EmitObjCPropertyGet(E, getReturnValueSlot());
EmitGCMove(E, RV);
}
void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
CGF.EmitAnyExpr(E->getLHS(), 0, false, true);
CGF.EmitAggExpr(E->getRHS(), DestPtr, VolatileDest,
/*IgnoreResult=*/false, IsInitializer);
}
void AggExprEmitter::VisitUnaryAddrOf(const UnaryOperator *E) {
// We have a member function pointer.
const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>();
(void) MPT;
assert(MPT->getPointeeType()->isFunctionProtoType() &&
"Unexpected member pointer type!");
// The creation of member function pointers has no side effects; if
// there is no destination pointer, we have nothing to do.
if (!DestPtr)
return;
const DeclRefExpr *DRE = cast<DeclRefExpr>(E->getSubExpr());
const CXXMethodDecl *MD =
cast<CXXMethodDecl>(DRE->getDecl())->getCanonicalDecl();
const llvm::Type *PtrDiffTy =
CGF.ConvertType(CGF.getContext().getPointerDiffType());
llvm::Value *DstPtr = Builder.CreateStructGEP(DestPtr, 0, "dst.ptr");
llvm::Value *FuncPtr = CGF.CGM.GetCXXMemberFunctionPointerValue(MD);
Builder.CreateStore(FuncPtr, DstPtr, VolatileDest);
llvm::Value *AdjPtr = Builder.CreateStructGEP(DestPtr, 1, "dst.adj");
// The adjustment will always be 0.
Builder.CreateStore(llvm::ConstantInt::get(PtrDiffTy, 0), AdjPtr,
VolatileDest);
}
void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
CGF.EmitCompoundStmt(*E->getSubStmt(), true, DestPtr, VolatileDest);
}
void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
if (E->getOpcode() == BinaryOperator::PtrMemD ||
E->getOpcode() == BinaryOperator::PtrMemI)
VisitPointerToDataMemberBinaryOperator(E);
else
CGF.ErrorUnsupported(E, "aggregate binary expression");
}
void AggExprEmitter::VisitPointerToDataMemberBinaryOperator(
const BinaryOperator *E) {
LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E);
EmitFinalDestCopy(E, LV);
}
void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
// For an assignment to work, the value on the right has
// to be compatible with the value on the left.
assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(),
E->getRHS()->getType())
&& "Invalid assignment");
LValue LHS = CGF.EmitLValue(E->getLHS());
// We have to special case property setters, otherwise we must have
// a simple lvalue (no aggregates inside vectors, bitfields).
if (LHS.isPropertyRef()) {
llvm::Value *AggLoc = DestPtr;
if (!AggLoc)
AggLoc = CGF.CreateMemTemp(E->getRHS()->getType());
CGF.EmitAggExpr(E->getRHS(), AggLoc, VolatileDest);
CGF.EmitObjCPropertySet(LHS.getPropertyRefExpr(),
RValue::getAggregate(AggLoc, VolatileDest));
} else if (LHS.isKVCRef()) {
llvm::Value *AggLoc = DestPtr;
if (!AggLoc)
AggLoc = CGF.CreateMemTemp(E->getRHS()->getType());
CGF.EmitAggExpr(E->getRHS(), AggLoc, VolatileDest);
CGF.EmitObjCPropertySet(LHS.getKVCRefExpr(),
RValue::getAggregate(AggLoc, VolatileDest));
} else {
bool RequiresGCollection = false;
if (CGF.getContext().getLangOptions().getGCMode())
RequiresGCollection = TypeRequiresGCollection(E->getLHS()->getType());
// Codegen the RHS so that it stores directly into the LHS.
CGF.EmitAggExpr(E->getRHS(), LHS.getAddress(), LHS.isVolatileQualified(),
false, false, RequiresGCollection);
EmitFinalDestCopy(E, LHS, true);
}
}
void AggExprEmitter::VisitConditionalOperator(const ConditionalOperator *E) {
if (!E->getLHS()) {
CGF.ErrorUnsupported(E, "conditional operator with missing LHS");
return;
}
llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
CGF.BeginConditionalBranch();
CGF.EmitBlock(LHSBlock);
// Handle the GNU extension for missing LHS.
assert(E->getLHS() && "Must have LHS for aggregate value");
Visit(E->getLHS());
CGF.EndConditionalBranch();
CGF.EmitBranch(ContBlock);
CGF.BeginConditionalBranch();
CGF.EmitBlock(RHSBlock);
Visit(E->getRHS());
CGF.EndConditionalBranch();
CGF.EmitBranch(ContBlock);
CGF.EmitBlock(ContBlock);
}
void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) {
Visit(CE->getChosenSubExpr(CGF.getContext()));
}
void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr());
llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType());
if (!ArgPtr) {
CGF.ErrorUnsupported(VE, "aggregate va_arg expression");
return;
}
EmitFinalDestCopy(VE, LValue::MakeAddr(ArgPtr, Qualifiers()));
}
void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
llvm::Value *Val = DestPtr;
if (!Val) {
// Create a temporary variable.
Val = CGF.CreateMemTemp(E->getType(), "tmp");
// FIXME: volatile
CGF.EmitAggExpr(E->getSubExpr(), Val, false);
} else
Visit(E->getSubExpr());
// Don't make this a live temporary if we're emitting an initializer expr.
if (!IsInitializer)
CGF.EmitCXXTemporary(E->getTemporary(), Val);
}
void
AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) {
llvm::Value *Val = DestPtr;
if (!Val) // Create a temporary variable.
Val = CGF.CreateMemTemp(E->getType(), "tmp");
if (E->requiresZeroInitialization())
EmitNullInitializationToLValue(LValue::MakeAddr(Val,
// FIXME: Qualifiers()?
E->getType().getQualifiers()),
E->getType());
CGF.EmitCXXConstructExpr(Val, E);
}
void AggExprEmitter::VisitCXXExprWithTemporaries(CXXExprWithTemporaries *E) {
llvm::Value *Val = DestPtr;
CGF.EmitCXXExprWithTemporaries(E, Val, VolatileDest, IsInitializer);
}
void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) {
llvm::Value *Val = DestPtr;
if (!Val) {
// Create a temporary variable.
Val = CGF.CreateMemTemp(E->getType(), "tmp");
}
LValue LV = LValue::MakeAddr(Val, Qualifiers());
EmitNullInitializationToLValue(LV, E->getType());
}
void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
llvm::Value *Val = DestPtr;
if (!Val) {
// Create a temporary variable.
Val = CGF.CreateMemTemp(E->getType(), "tmp");
}
LValue LV = LValue::MakeAddr(Val, Qualifiers());
EmitNullInitializationToLValue(LV, E->getType());
}
void
AggExprEmitter::EmitInitializationToLValue(Expr* E, LValue LV, QualType T) {
// FIXME: Ignore result?
// FIXME: Are initializers affected by volatile?
if (isa<ImplicitValueInitExpr>(E)) {
EmitNullInitializationToLValue(LV, T);
} else if (T->isReferenceType()) {
RValue RV = CGF.EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0);
CGF.EmitStoreThroughLValue(RV, LV, T);
} else if (T->isAnyComplexType()) {
CGF.EmitComplexExprIntoAddr(E, LV.getAddress(), false);
} else if (CGF.hasAggregateLLVMType(T)) {
CGF.EmitAnyExpr(E, LV.getAddress(), false);
} else {
CGF.EmitStoreThroughLValue(CGF.EmitAnyExpr(E), LV, T);
}
}
void AggExprEmitter::EmitNullInitializationToLValue(LValue LV, QualType T) {
if (!CGF.hasAggregateLLVMType(T)) {
// For non-aggregates, we can store zero
llvm::Value *Null = llvm::Constant::getNullValue(CGF.ConvertType(T));
CGF.EmitStoreThroughLValue(RValue::get(Null), LV, T);
} else {
// There's a potential optimization opportunity in combining
// memsets; that would be easy for arrays, but relatively
// difficult for structures with the current code.
CGF.EmitNullInitialization(LV.getAddress(), T);
}
}
void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
#if 0
// FIXME: Assess perf here? Figure out what cases are worth optimizing here
// (Length of globals? Chunks of zeroed-out space?).
//
// If we can, prefer a copy from a global; this is a lot less code for long
// globals, and it's easier for the current optimizers to analyze.
if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) {
llvm::GlobalVariable* GV =
new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true,
llvm::GlobalValue::InternalLinkage, C, "");
EmitFinalDestCopy(E, LValue::MakeAddr(GV, Qualifiers()));
return;
}
#endif
if (E->hadArrayRangeDesignator()) {
CGF.ErrorUnsupported(E, "GNU array range designator extension");
}
// Handle initialization of an array.
if (E->getType()->isArrayType()) {
const llvm::PointerType *APType =
cast<llvm::PointerType>(DestPtr->getType());
const llvm::ArrayType *AType =
cast<llvm::ArrayType>(APType->getElementType());
uint64_t NumInitElements = E->getNumInits();
if (E->getNumInits() > 0) {
QualType T1 = E->getType();
QualType T2 = E->getInit(0)->getType();
if (CGF.getContext().hasSameUnqualifiedType(T1, T2)) {
EmitAggLoadOfLValue(E->getInit(0));
return;
}
}
uint64_t NumArrayElements = AType->getNumElements();
QualType ElementType = CGF.getContext().getCanonicalType(E->getType());
ElementType = CGF.getContext().getAsArrayType(ElementType)->getElementType();
// FIXME: were we intentionally ignoring address spaces and GC attributes?
Qualifiers Quals = CGF.MakeQualifiers(ElementType);
for (uint64_t i = 0; i != NumArrayElements; ++i) {
llvm::Value *NextVal = Builder.CreateStructGEP(DestPtr, i, ".array");
if (i < NumInitElements)
EmitInitializationToLValue(E->getInit(i),
LValue::MakeAddr(NextVal, Quals),
ElementType);
else
EmitNullInitializationToLValue(LValue::MakeAddr(NextVal, Quals),
ElementType);
}
return;
}
assert(E->getType()->isRecordType() && "Only support structs/unions here!");
// Do struct initialization; this code just sets each individual member
// to the approprate value. This makes bitfield support automatic;
// the disadvantage is that the generated code is more difficult for
// the optimizer, especially with bitfields.
unsigned NumInitElements = E->getNumInits();
RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl();
unsigned CurInitVal = 0;
if (E->getType()->isUnionType()) {
// Only initialize one field of a union. The field itself is
// specified by the initializer list.
if (!E->getInitializedFieldInUnion()) {
// Empty union; we have nothing to do.
#ifndef NDEBUG
// Make sure that it's really an empty and not a failure of
// semantic analysis.
for (RecordDecl::field_iterator Field = SD->field_begin(),
FieldEnd = SD->field_end();
Field != FieldEnd; ++Field)
assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed");
#endif
return;
}
// FIXME: volatility
FieldDecl *Field = E->getInitializedFieldInUnion();
LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestPtr, Field, 0);
if (NumInitElements) {
// Store the initializer into the field
EmitInitializationToLValue(E->getInit(0), FieldLoc, Field->getType());
} else {
// Default-initialize to null
EmitNullInitializationToLValue(FieldLoc, Field->getType());
}
return;
}
// If we're initializing the whole aggregate, just do it in place.
// FIXME: This is a hack around an AST bug (PR6537).
if (NumInitElements == 1 && E->getType() == E->getInit(0)->getType()) {
EmitInitializationToLValue(E->getInit(0),
LValue::MakeAddr(DestPtr, Qualifiers()),
E->getType());
return;
}
// Here we iterate over the fields; this makes it simpler to both
// default-initialize fields and skip over unnamed fields.
for (RecordDecl::field_iterator Field = SD->field_begin(),
FieldEnd = SD->field_end();
Field != FieldEnd; ++Field) {
// We're done once we hit the flexible array member
if (Field->getType()->isIncompleteArrayType())
break;
if (Field->isUnnamedBitfield())
continue;
// FIXME: volatility
LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestPtr, *Field, 0);
// We never generate write-barries for initialized fields.
LValue::SetObjCNonGC(FieldLoc, true);
if (CurInitVal < NumInitElements) {
// Store the initializer into the field.
EmitInitializationToLValue(E->getInit(CurInitVal++), FieldLoc,
Field->getType());
} else {
// We're out of initalizers; default-initialize to null
EmitNullInitializationToLValue(FieldLoc, Field->getType());
}
}
}
//===----------------------------------------------------------------------===//
// Entry Points into this File
//===----------------------------------------------------------------------===//
/// EmitAggExpr - Emit the computation of the specified expression of aggregate
/// type. The result is computed into DestPtr. Note that if DestPtr is null,
/// the value of the aggregate expression is not needed. If VolatileDest is
/// true, DestPtr cannot be 0.
//
// FIXME: Take Qualifiers object.
void CodeGenFunction::EmitAggExpr(const Expr *E, llvm::Value *DestPtr,
bool VolatileDest, bool IgnoreResult,
bool IsInitializer,
bool RequiresGCollection) {
assert(E && hasAggregateLLVMType(E->getType()) &&
"Invalid aggregate expression to emit");
assert ((DestPtr != 0 || VolatileDest == false)
&& "volatile aggregate can't be 0");
AggExprEmitter(*this, DestPtr, VolatileDest, IgnoreResult, IsInitializer,
RequiresGCollection)
.Visit(const_cast<Expr*>(E));
}
LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {
assert(hasAggregateLLVMType(E->getType()) && "Invalid argument!");
Qualifiers Q = MakeQualifiers(E->getType());
llvm::Value *Temp = CreateMemTemp(E->getType());
EmitAggExpr(E, Temp, Q.hasVolatile());
return LValue::MakeAddr(Temp, Q);
}
void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr,
llvm::Value *SrcPtr, QualType Ty,
bool isVolatile) {
assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
if (getContext().getLangOptions().CPlusPlus) {
if (const RecordType *RT = Ty->getAs<RecordType>()) {
CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
assert((Record->hasTrivialCopyConstructor() ||
Record->hasTrivialCopyAssignment()) &&
"Trying to aggregate-copy a type without a trivial copy "
"constructor or assignment operator");
// Ignore empty classes in C++.
if (Record->isEmpty())
return;
}
}
// Aggregate assignment turns into llvm.memcpy. This is almost valid per
// C99 6.5.16.1p3, which states "If the value being stored in an object is
// read from another object that overlaps in anyway the storage of the first
// object, then the overlap shall be exact and the two objects shall have
// qualified or unqualified versions of a compatible type."
//
// memcpy is not defined if the source and destination pointers are exactly
// equal, but other compilers do this optimization, and almost every memcpy
// implementation handles this case safely. If there is a libc that does not
// safely handle this, we can add a target hook.
// Get size and alignment info for this aggregate.
std::pair<uint64_t, unsigned> TypeInfo = getContext().getTypeInfo(Ty);
// FIXME: Handle variable sized types.
// FIXME: If we have a volatile struct, the optimizer can remove what might
// appear to be `extra' memory ops:
//
// volatile struct { int i; } a, b;
//
// int main() {
// a = b;
// a = b;
// }
//
// we need to use a different call here. We use isVolatile to indicate when
// either the source or the destination is volatile.
const llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType());
const llvm::Type *DBP =
llvm::Type::getInt8PtrTy(VMContext, DPT->getAddressSpace());
DestPtr = Builder.CreateBitCast(DestPtr, DBP, "tmp");
const llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType());
const llvm::Type *SBP =
llvm::Type::getInt8PtrTy(VMContext, SPT->getAddressSpace());
SrcPtr = Builder.CreateBitCast(SrcPtr, SBP, "tmp");
if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
RecordDecl *Record = RecordTy->getDecl();
if (Record->hasObjectMember()) {
unsigned long size = TypeInfo.first/8;
const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size);
CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
SizeVal);
return;
}
} else if (getContext().getAsArrayType(Ty)) {
QualType BaseType = getContext().getBaseElementType(Ty);
if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) {
if (RecordTy->getDecl()->hasObjectMember()) {
unsigned long size = TypeInfo.first/8;
const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size);
CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr,
SizeVal);
return;
}
}
}
Builder.CreateCall5(CGM.getMemCpyFn(DestPtr->getType(), SrcPtr->getType(),
IntPtrTy),
DestPtr, SrcPtr,
// TypeInfo.first describes size in bits.
llvm::ConstantInt::get(IntPtrTy, TypeInfo.first/8),
Builder.getInt32(TypeInfo.second/8),
Builder.getInt1(isVolatile));
}