/// Return the type returned by DtoUnpaddedStruct called on a value of the
/// specified type.
/// Union types will get expanded into a struct, with a type for each member.
LLType* DtoUnpaddedStructType(Type* dty) {
assert(dty->ty == Tstruct);
typedef llvm::DenseMap<Type*, llvm::StructType*> CacheT;
static llvm::ManagedStatic<CacheT> cache;
CacheT::iterator it = cache->find(dty);
if (it != cache->end())
return it->second;
TypeStruct* sty = static_cast<TypeStruct*>(dty);
VarDeclarations& fields = sty->sym->fields;
std::vector<LLType*> types;
types.reserve(fields.dim);
for (unsigned i = 0; i < fields.dim; i++) {
LLType* fty;
if (fields[i]->type->ty == Tstruct) {
// Nested structs are the only members that can contain padding
fty = DtoUnpaddedStructType(fields[i]->type);
} else {
fty = DtoType(fields[i]->type);
}
types.push_back(fty);
}
LLStructType* Ty = LLStructType::get(gIR->context(), types);
cache->insert(std::make_pair(dty, Ty));
return Ty;
}
void fixup(IrFuncTyArg& arg) {
assert(arg.type->ty == Tstruct);
// TODO: Check that no unions are passed in or returned.
LLType* abiTy = DtoUnpaddedStructType(arg.type);
if (abiTy && abiTy != arg.ltype) {
arg.ltype = abiTy;
arg.rewrite = &remove_padding;
}
}
/// Return the struct value represented by v without the padding fields.
/// Unions will be expanded, with a value for each member.
/// Note: v must be a pointer to a struct, but the return value will be a
/// first-class struct value.
LLValue* DtoUnpaddedStruct(Type* dty, LLValue* v) {
assert(dty->ty == Tstruct);
TypeStruct* sty = static_cast<TypeStruct*>(dty);
VarDeclarations& fields = sty->sym->fields;
LLValue* newval = llvm::UndefValue::get(DtoUnpaddedStructType(dty));
for (unsigned i = 0; i < fields.dim; i++) {
LLValue* fieldptr = DtoIndexAggregate(v, sty->sym, fields[i]);
LLValue* fieldval;
if (fields[i]->type->ty == Tstruct) {
// Nested structs are the only members that can contain padding
fieldval = DtoUnpaddedStruct(fields[i]->type, fieldptr);
} else {
fieldval = DtoLoad(fieldptr);
}
newval = DtoInsertValue(newval, fieldval, i);
}
return newval;
}
/// Return the struct value represented by v without the padding fields.
/// Unions will be expanded, with a value for each member.
/// Note: v must be a pointer to a struct, but the return value will be a
/// first-class struct value.
LLValue* DtoUnpaddedStruct(Type* dty, LLValue* v) {
assert(dty->ty == Tstruct);
TypeStruct* sty = (TypeStruct*) dty;
Array& fields = sty->sym->fields;
LLValue* newval = llvm::UndefValue::get(DtoUnpaddedStructType(dty));
for (unsigned i = 0; i < fields.dim; i++) {
VarDeclaration* vd = (VarDeclaration*) fields.data[i];
LLValue* fieldptr = DtoIndexStruct(v, sty->sym, vd);
LLValue* fieldval;
if (vd->type->ty == Tstruct) {
// Nested structs are the only members that can contain padding
fieldval = DtoUnpaddedStruct(vd->type, fieldptr);
} else {
fieldval = DtoLoad(fieldptr);
}
newval = DtoInsertValue(newval, fieldval, i);
}
return newval;
}