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Move code from EmitUnion directly into the function that handles cast-to-union. 

llvm-svn: 77735
This commit is contained in:
Anders Carlsson 2009-07-31 21:38:39 +00:00
parent 2358732164
commit d65ab045e8
1 changed files with 28 additions and 2 deletions
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30
clang/lib/CodeGen/CGExprConstant.cpp
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@ -378,9 +378,35 @@ public:
if (E->getType()->isUnionType()) {
const llvm::Type *Ty = ConvertType(E->getType());
Expr *SubExpr = E->getSubExpr();
return EmitUnion(CGM.EmitConstantExpr(SubExpr, SubExpr->getType(), CGF),
Ty);
llvm::Constant *C =
CGM.EmitConstantExpr(SubExpr, SubExpr->getType(), CGF);
if (!C)
return 0;
// Build a struct with the union sub-element as the first member,
// and padded to the appropriate size
std::vector<llvm::Constant*> Elts;
std::vector<const llvm::Type*> Types;
Elts.push_back(C);
Types.push_back(C->getType());
unsigned CurSize = CGM.getTargetData().getTypeAllocSize(C->getType());
unsigned TotalSize = CGM.getTargetData().getTypeAllocSize(Ty);
assert(CurSize <= TotalSize && "Union size mismatch!");
if (unsigned NumPadBytes = TotalSize - CurSize) {
const llvm::Type *Ty = llvm::Type::Int8Ty;
if (NumPadBytes > 1)
Ty = llvm::ArrayType::get(Ty, NumPadBytes);
Elts.push_back(llvm::Constant::getNullValue(Ty));
Types.push_back(Ty);
}
llvm::StructType* STy = llvm::StructType::get(Types, false);
return llvm::ConstantStruct::get(STy, Elts);
}
// Explicit and implicit no-op casts
QualType Ty = E->getType(), SubTy = E->getSubExpr()->getType();
if (CGM.getContext().hasSameUnqualifiedType(Ty, SubTy)) {