bool GetFields( RecordDecl * rd, Obj * entries) {
//check the fields of this struct, if any one of them is not understandable, then this struct becomes 'opaque'
//that is, we insert the type, and link it to its llvm type, so it can be used in terra code
//but none of its fields are exposed (since we don't understand the layout)
bool opaque = false;
for(RecordDecl::field_iterator it = rd->field_begin(), end = rd->field_end(); it != end; ++it) {
if(it->isBitField() || it->isAnonymousStructOrUnion() || !it->getDeclName()) {
opaque = true;
continue;
}
DeclarationName declname = it->getDeclName();
std::string declstr = declname.getAsString();
QualType FT = it->getType();
Obj fobj;
if(!GetType(FT,&fobj)) {
opaque = true;
continue;
}
lua_newtable(L);
fobj.push();
lua_setfield(L,-2,"type");
lua_pushstring(L,declstr.c_str());
lua_setfield(L,-2,"field");
entries->addentry();
}
return !opaque;
}
void CGRecordLayoutBuilder::LayoutUnion(const RecordDecl *D) {
assert(D->isUnion() && "Can't call LayoutUnion on a non-union record!");
const ASTRecordLayout &layout = Types.getContext().getASTRecordLayout(D);
llvm::Type *unionType = 0;
CharUnits unionSize = CharUnits::Zero();
CharUnits unionAlign = CharUnits::Zero();
bool hasOnlyZeroSizedBitFields = true;
bool checkedFirstFieldZeroInit = false;
unsigned fieldNo = 0;
for (RecordDecl::field_iterator field = D->field_begin(),
fieldEnd = D->field_end(); field != fieldEnd; ++field, ++fieldNo) {
assert(layout.getFieldOffset(fieldNo) == 0 &&
"Union field offset did not start at the beginning of record!");
llvm::Type *fieldType = LayoutUnionField(*field, layout);
if (!fieldType)
continue;
if (field->getDeclName() && !checkedFirstFieldZeroInit) {
CheckZeroInitializable(field->getType());
checkedFirstFieldZeroInit = true;
}
hasOnlyZeroSizedBitFields = false;
CharUnits fieldAlign = CharUnits::fromQuantity(
Types.getDataLayout().getABITypeAlignment(fieldType));
CharUnits fieldSize = CharUnits::fromQuantity(
Types.getDataLayout().getTypeAllocSize(fieldType));
if (fieldAlign < unionAlign)
continue;
if (fieldAlign > unionAlign || fieldSize > unionSize) {
unionType = fieldType;
unionAlign = fieldAlign;
unionSize = fieldSize;
}
}
// Now add our field.
if (unionType) {
AppendField(CharUnits::Zero(), unionType);
if (getTypeAlignment(unionType) > layout.getAlignment()) {
// We need a packed struct.
Packed = true;
unionAlign = CharUnits::One();
}
}
if (unionAlign.isZero()) {
(void)hasOnlyZeroSizedBitFields;
assert(hasOnlyZeroSizedBitFields &&
"0-align record did not have all zero-sized bit-fields!");
unionAlign = CharUnits::One();
}
// Append tail padding.
CharUnits recordSize = layout.getSize();
if (recordSize > unionSize)
AppendPadding(recordSize, unionAlign);
}