Hi Joseph,
On 8/20/25 15:49, Joseph Myers wrote:
> On Tue, 12 Aug 2025, David Faust wrote:
>
>> + if (TREE_CODE (*node) == FUNCTION_TYPE || TREE_CODE (*node) ==
>> METHOD_TYPE)
>> + {
>> + /* Treat btf_type_tag applied to a function type as applying to the
>> + return type instead. Otherwise with GNU syntax there is no way to
>> + apply type_tag to the return type; the parser always associates it
>> + to the function_type node. btf_decl_tag can (should) be used to
>> + annotate the function itself. */
>> + tree ret_type = TREE_TYPE (*node);
>> + tree new_attrs = tree_cons (name, args, TYPE_ATTRIBUTES (ret_type));
>> + tree new_type = build_type_attribute_qual_variant (ret_type,
>> + new_attrs,
>> + TYPE_QUALS (ret_type));
>> + TREE_TYPE (*node) = new_type;
>
> Is there some reason it's impossible for the function type here to be in
> use for any other declaration? If not, modifying the return type of the
> existing function type in-place like this seems unsafe.
>
No, I suppose there is no such reason. Do you mean that I need to use
reconstruct_complex_type langhook here similar to the vector_size attribute
handler? Or do you know some better/"more proper" way to solve this problem?
Alternatively, I suppose we could simply say, if you want to tag the return
type you must use c2x syntax to do so. And delete the whole if {..}.
Thanks
