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Handle base-to-derived casts. Will land test case shortly. 

llvm-svn: 89678
This commit is contained in:
Anders Carlsson 2009-11-23 17:57:54 +00:00
parent d976d3e552
commit 8c793172c2
5 changed files with 154 additions and 52 deletions
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28
clang/lib/CodeGen/CGCXX.cpp
View File

@ -1211,10 +1211,10 @@ void CodeGenFunction::EmitClassMemberwiseCopy(
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl, QualType Ty) {
if (ClassDecl) {
Dest = GetAddressCXXOfBaseClass(Dest, ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
Src = GetAddressCXXOfBaseClass(Src, ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
Dest = GetAddressOfBaseClass(Dest, ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
Src = GetAddressOfBaseClass(Src, ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
}
if (BaseClassDecl->hasTrivialCopyConstructor()) {
EmitAggregateCopy(Dest, Src, Ty);
@ -1250,10 +1250,10 @@ void CodeGenFunction::EmitClassCopyAssignment(
const CXXRecordDecl *BaseClassDecl,
QualType Ty) {
if (ClassDecl) {
Dest = GetAddressCXXOfBaseClass(Dest, ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
Src = GetAddressCXXOfBaseClass(Src, ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
Dest = GetAddressOfBaseClass(Dest, ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
Src = GetAddressOfBaseClass(Src, ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
}
if (BaseClassDecl->hasTrivialCopyAssignment()) {
EmitAggregateCopy(Dest, Src, Ty);
@ -1493,9 +1493,9 @@ static void EmitBaseInitializer(CodeGenFunction &CGF,
const Type *BaseType = BaseInit->getBaseClass();
CXXRecordDecl *BaseClassDecl =
cast<CXXRecordDecl>(BaseType->getAs<RecordType>()->getDecl());
llvm::Value *V = CGF.GetAddressCXXOfBaseClass(ThisPtr, ClassDecl,
BaseClassDecl,
/*NullCheckValue=*/false);
llvm::Value *V = CGF.GetAddressOfBaseClass(ThisPtr, ClassDecl,
BaseClassDecl,
/*NullCheckValue=*/false);
CGF.EmitCXXConstructorCall(BaseInit->getConstructor(),
CtorType, V,
BaseInit->const_arg_begin(),
@ -1710,9 +1710,9 @@ void CodeGenFunction::EmitDtorEpilogue(const CXXDestructorDecl *DD,
if (BaseClassDecl->hasTrivialDestructor())
continue;
llvm::Value *V = GetAddressCXXOfBaseClass(LoadCXXThis(),
ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
llvm::Value *V = GetAddressOfBaseClass(LoadCXXThis(),
ClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
EmitCXXDestructorCall(BaseClassDecl->getDestructor(getContext()),
Dtor_Base, V);
}

92
clang/lib/CodeGen/CGCXXClass.cpp
View File

@ -117,10 +117,10 @@ static llvm::Value *GetCXXBaseClassOffset(CodeGenFunction &CGF,
}
llvm::Value *
CodeGenFunction::GetAddressCXXOfBaseClass(llvm::Value *BaseValue,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl,
bool NullCheckValue) {
CodeGenFunction::GetAddressOfBaseClass(llvm::Value *Value,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl,
bool NullCheckValue) {
QualType BTy =
getContext().getCanonicalType(
getContext().getTypeDeclType(const_cast<CXXRecordDecl*>(BaseClassDecl)));
@ -128,7 +128,7 @@ CodeGenFunction::GetAddressCXXOfBaseClass(llvm::Value *BaseValue,
if (ClassDecl == BaseClassDecl) {
// Just cast back.
return Builder.CreateBitCast(BaseValue, BasePtrTy);
return Builder.CreateBitCast(Value, BasePtrTy);
}
llvm::BasicBlock *CastNull = 0;
@ -141,8 +141,8 @@ CodeGenFunction::GetAddressCXXOfBaseClass(llvm::Value *BaseValue,
CastEnd = createBasicBlock("cast.end");
llvm::Value *IsNull =
Builder.CreateICmpEQ(BaseValue,
llvm::Constant::getNullValue(BaseValue->getType()));
Builder.CreateICmpEQ(Value,
llvm::Constant::getNullValue(Value->getType()));
Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
EmitBlock(CastNotNull);
}
@ -150,16 +150,16 @@ CodeGenFunction::GetAddressCXXOfBaseClass(llvm::Value *BaseValue,
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
llvm::Value *Offset =
GetCXXBaseClassOffset(*this, BaseValue, ClassDecl, BaseClassDecl);
GetCXXBaseClassOffset(*this, Value, ClassDecl, BaseClassDecl);
if (Offset) {
// Apply the offset.
BaseValue = Builder.CreateBitCast(BaseValue, Int8PtrTy);
BaseValue = Builder.CreateGEP(BaseValue, Offset, "add.ptr");
Value = Builder.CreateBitCast(Value, Int8PtrTy);
Value = Builder.CreateGEP(Value, Offset, "add.ptr");
}
// Cast back.
BaseValue = Builder.CreateBitCast(BaseValue, BasePtrTy);
Value = Builder.CreateBitCast(Value, BasePtrTy);
if (NullCheckValue) {
Builder.CreateBr(CastEnd);
@ -167,13 +167,73 @@ CodeGenFunction::GetAddressCXXOfBaseClass(llvm::Value *BaseValue,
Builder.CreateBr(CastEnd);
EmitBlock(CastEnd);
llvm::PHINode *PHI = Builder.CreatePHI(BaseValue->getType());
llvm::PHINode *PHI = Builder.CreatePHI(Value->getType());
PHI->reserveOperandSpace(2);
PHI->addIncoming(BaseValue, CastNotNull);
PHI->addIncoming(llvm::Constant::getNullValue(BaseValue->getType()),
PHI->addIncoming(Value, CastNotNull);
PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()),
CastNull);
BaseValue = PHI;
Value = PHI;
}
return BaseValue;
return Value;
}
llvm::Value *
CodeGenFunction::GetAddressOfDerivedClass(llvm::Value *Value,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *DerivedClassDecl,
bool NullCheckValue) {
QualType DerivedTy =
getContext().getCanonicalType(
getContext().getTypeDeclType(const_cast<CXXRecordDecl*>(DerivedClassDecl)));
const llvm::Type *DerivedPtrTy = ConvertType(DerivedTy)->getPointerTo();
if (ClassDecl == DerivedClassDecl) {
// Just cast back.
return Builder.CreateBitCast(Value, DerivedPtrTy);
}
llvm::BasicBlock *CastNull = 0;
llvm::BasicBlock *CastNotNull = 0;
llvm::BasicBlock *CastEnd = 0;
if (NullCheckValue) {
CastNull = createBasicBlock("cast.null");
CastNotNull = createBasicBlock("cast.notnull");
CastEnd = createBasicBlock("cast.end");
llvm::Value *IsNull =
Builder.CreateICmpEQ(Value,
llvm::Constant::getNullValue(Value->getType()));
Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
EmitBlock(CastNotNull);
}
llvm::Value *Offset = GetCXXBaseClassOffset(*this, Value, DerivedClassDecl,
ClassDecl);
if (Offset) {
// Apply the offset.
Value = Builder.CreatePtrToInt(Value, Offset->getType());
Value = Builder.CreateSub(Value, Offset);
Value = Builder.CreateIntToPtr(Value, DerivedPtrTy);
} else {
// Just cast.
Value = Builder.CreateBitCast(Value, DerivedPtrTy);
}
if (NullCheckValue) {
Builder.CreateBr(CastEnd);
EmitBlock(CastNull);
Builder.CreateBr(CastEnd);
EmitBlock(CastEnd);
llvm::PHINode *PHI = Builder.CreatePHI(Value->getType());
PHI->reserveOperandSpace(2);
PHI->addIncoming(Value, CastNotNull);
PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()),
CastNull);
Value = PHI;
}
return Value;
}

26
clang/lib/CodeGen/CGExpr.cpp
View File

@ -148,8 +148,8 @@ RValue CodeGenFunction::EmitReferenceBindingToExpr(const Expr* E,
if (BaseClassDecl) {
llvm::Value *Derived = Val.getAggregateAddr();
llvm::Value *Base =
GetAddressCXXOfBaseClass(Derived, DerivedClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
GetAddressOfBaseClass(Derived, DerivedClassDecl, BaseClassDecl,
/*NullCheckValue=*/false);
return RValue::get(Base);
}
}
@ -1328,8 +1328,8 @@ LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
// Perform the derived-to-base conversion
llvm::Value *Base =
GetAddressCXXOfBaseClass(LV.getAddress(), DerivedClassDecl,
BaseClassDecl, /*NullCheckValue=*/false);
GetAddressOfBaseClass(LV.getAddress(), DerivedClassDecl,
BaseClassDecl, /*NullCheckValue=*/false);
return LValue::MakeAddr(Base, MakeQualifiers(E->getType()));
}
@ -1340,7 +1340,23 @@ LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
}
case CastExpr::CK_BaseToDerived: {
return EmitUnsupportedLValue(E, "base-to-derived cast lvalue");
const RecordType *BaseClassTy =
E->getSubExpr()->getType()->getAs<RecordType>();
CXXRecordDecl *BaseClassDecl =
cast<CXXRecordDecl>(BaseClassTy->getDecl());
const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
CXXRecordDecl *DerivedClassDecl =
cast<CXXRecordDecl>(DerivedClassTy->getDecl());
LValue LV = EmitLValue(E->getSubExpr());
// Perform the base-to-derived conversion
llvm::Value *Derived =
GetAddressOfDerivedClass(LV.getAddress(), BaseClassDecl,
DerivedClassDecl, /*NullCheckValue=*/false);
return LValue::MakeAddr(Derived, MakeQualifiers(E->getType()));
}
case CastExpr::CK_BitCast: {
// This must be a reinterpret_cast (or c-style equivalent).

45
clang/lib/CodeGen/CGExprScalar.cpp
View File

@ -748,6 +748,23 @@ Value *ScalarExprEmitter::VisitInitListExpr(InitListExpr *E) {
return V;
}
static bool ShouldNullCheckClassCastValue(const CastExpr *CE) {
const Expr *E = CE->getSubExpr();
if (isa<CXXThisExpr>(E)) {
// We always assume that 'this' is never null.
return false;
}
if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(CE)) {
// And that lvalue casts are never null.
if (ICE->isLvalueCast())
return false;
}
return true;
}
// VisitCastExpr - Emit code for an explicit or implicit cast. Implicit casts
// have to handle a more broad range of conversions than explicit casts, as they
// handle things like function to ptr-to-function decay etc.
@ -775,6 +792,19 @@ Value *ScalarExprEmitter::EmitCastExpr(const CastExpr *CE) {
case CastExpr::CK_NoOp:
return Visit(const_cast<Expr*>(E));
case CastExpr::CK_BaseToDerived: {
const CXXRecordDecl *BaseClassDecl =
E->getType()->getCXXRecordDeclForPointerType();
const CXXRecordDecl *DerivedClassDecl =
DestTy->getCXXRecordDeclForPointerType();
Value *Src = Visit(const_cast<Expr*>(E));
bool NullCheckValue = ShouldNullCheckClassCastValue(CE);
return CGF.GetAddressOfDerivedClass(Src, BaseClassDecl, DerivedClassDecl,
NullCheckValue);
}
case CastExpr::CK_DerivedToBase: {
const RecordType *DerivedClassTy =
E->getType()->getAs<PointerType>()->getPointeeType()->getAs<RecordType>();
@ -787,18 +817,9 @@ Value *ScalarExprEmitter::EmitCastExpr(const CastExpr *CE) {
Value *Src = Visit(const_cast<Expr*>(E));
bool NullCheckValue = true;
if (isa<CXXThisExpr>(E)) {
// We always assume that 'this' is never null.
NullCheckValue = false;
} else if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(CE)) {
// And that lvalue casts are never null.
if (ICE->isLvalueCast())
NullCheckValue = false;
}
return CGF.GetAddressCXXOfBaseClass(Src, DerivedClassDecl, BaseClassDecl,
NullCheckValue);
bool NullCheckValue = ShouldNullCheckClassCastValue(CE);
return CGF.GetAddressOfBaseClass(Src, DerivedClassDecl, BaseClassDecl,
NullCheckValue);
}
case CastExpr::CK_ToUnion: {
assert(0 && "Should be unreachable!");

15
clang/lib/CodeGen/CodeGenFunction.h
View File

@ -598,15 +598,20 @@ public:
/// generating code for an C++ member function.
llvm::Value *LoadCXXThis();
/// GetAddressCXXOfBaseClass - This function will add the necessary delta
/// GetAddressOfBaseClass - This function will add the necessary delta
/// to the load of 'this' and returns address of the base class.
// FIXME. This currently only does a derived to non-virtual base conversion.
// Other kinds of conversions will come later.
llvm::Value *GetAddressCXXOfBaseClass(llvm::Value *BaseValue,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl,
bool NullCheckValue);
llvm::Value *GetAddressOfBaseClass(llvm::Value *Value,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl,
bool NullCheckValue);
llvm::Value *GetAddressOfDerivedClass(llvm::Value *Value,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *DerivedClassDecl,
bool NullCheckValue);
llvm::Value *
GetVirtualCXXBaseClassOffset(llvm::Value *This,
const CXXRecordDecl *ClassDecl,