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Restructure constant structure init codegen so that it's possible to 

implement bitfield codegen (although I don't envy the person who 
implements it).  This also prevents a crash on code like that from PR2309
(it's still broken, but it fails more gracefully).

llvm-svn: 51285
This commit is contained in:
Eli Friedman 2008-05-20 00:11:07 +00:00
parent 8d0b976e7c
commit 247ee87e26
1 changed files with 24 additions and 33 deletions
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57
clang/lib/CodeGen/CGExprConstant.cpp
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@ -91,7 +91,6 @@ public:
// Copy initializer elements. // Copy initializer elements.
unsigned i = 0; unsigned i = 0;
for (; i < NumInitableElts; ++i) { for (; i < NumInitableElts; ++i) {
llvm::Constant *C = Visit(ILE->getInit(i)); llvm::Constant *C = Visit(ILE->getInit(i));
assert (C && "Failed to create initializer expression"); assert (C && "Failed to create initializer expression");
Elts.push_back(C); Elts.push_back(C);
@ -107,42 +106,35 @@ public:
llvm::Constant *EmitStructInitialization(InitListExpr *ILE, llvm::Constant *EmitStructInitialization(InitListExpr *ILE,
const llvm::StructType *SType) { const llvm::StructType *SType) {
TagDecl *TD = ILE->getType()->getAsRecordType()->getDecl(); RecordDecl *RD = ILE->getType()->getAsRecordType()->getDecl();
std::vector<llvm::Constant*> Elts; std::vector<llvm::Constant*> Elts;
const CGRecordLayout *CGR = CGM.getTypes().getCGRecordLayout(TD);
unsigned NumInitElements = ILE->getNumInits();
unsigned NumElements = SType->getNumElements();
// Initialising an structure requires us to automatically
// initialise any elements that have not been initialised explicitly
unsigned NumInitableElts = std::min(NumInitElements, NumElements);
// Copy initializer elements. Skip padding fields. // Initialize the whole structure to zero.
unsigned EltNo = 0; // Element no in ILE for (unsigned i = 0; i < SType->getNumElements(); ++i) {
unsigned FieldNo = 0; // Field no in SType
while (EltNo < NumInitableElts) {
// Zero initialize padding field.
if (CGR->isPaddingField(FieldNo)) {
const llvm::Type *FieldTy = SType->getElementType(FieldNo);
Elts.push_back(llvm::Constant::getNullValue(FieldTy));
FieldNo++;
continue;
}
llvm::Constant *C = Visit(ILE->getInit(EltNo));
assert (C && "Failed to create initializer expression");
Elts.push_back(C);
EltNo++;
FieldNo++;
}
// Initialize remaining structure elements.
for (unsigned i = Elts.size(); i < NumElements; ++i) {
const llvm::Type *FieldTy = SType->getElementType(i); const llvm::Type *FieldTy = SType->getElementType(i);
Elts.push_back(llvm::Constant::getNullValue(FieldTy)); Elts.push_back(llvm::Constant::getNullValue(FieldTy));
} }
// Copy initializer elements. Skip padding fields.
unsigned EltNo = 0; // Element no in ILE
int FieldNo = 0; // Field no in RecordDecl
while (EltNo < ILE->getNumInits() && FieldNo < RD->getNumMembers()) {
FieldDecl* curField = RD->getMember(FieldNo);
FieldNo++;
if (!curField->getIdentifier())
continue;
llvm::Constant *C = Visit(ILE->getInit(EltNo));
assert (C && "Failed to create initializer expression");
if (curField->isBitField()) {
CGM.WarnUnsupported(ILE->getInit(EltNo), "bitfield initialization");
} else {
Elts[CGM.getTypes().getLLVMFieldNo(curField)] = C;
}
EltNo++;
}
return llvm::ConstantStruct::get(SType, Elts); return llvm::ConstantStruct::get(SType, Elts);
} }
@ -158,7 +150,6 @@ public:
// Copy initializer elements. // Copy initializer elements.
unsigned i = 0; unsigned i = 0;
for (; i < NumElements; ++i) { for (; i < NumElements; ++i) {
llvm::Constant *C = Visit(ILE->getInit(i)); llvm::Constant *C = Visit(ILE->getInit(i));
assert (C && "Failed to create initializer expression"); assert (C && "Failed to create initializer expression");
Elts.push_back(C); Elts.push_back(C);