On Fri, Dec 15, 2017 at 03:02:50PM -0500, Jason Merrill wrote:
> On 12/07/2017 11:45 AM, Jakub Jelinek wrote:
> > save_template_attributes ignored flags, when ATTR_FLAG_TYPE_IN_PLACE
> > wasn't set on a type, it would happily attach the attributes to some
> > existing type (in this case to integer_type_node).
> >
> > My first approach was to just call build_type_attribute_variant, but
> > that ICEs on g++.dg/cpp0x/alias-decl-59.C, because there *decl_p is
> > UNDERLYING_TYPE, which the generic type_hash_canon
> > build_type_attribute_variant calls doesn't like.
>
> Ah, because it calls layout_type. What if we did this?
>
> Jason
> diff --git a/gcc/tree.c b/gcc/tree.c
> index ed1852b3e66..4883b711624 100644
> --- a/gcc/tree.c
> +++ b/gcc/tree.c
> @@ -6445,7 +6445,8 @@ type_hash_canon (unsigned int hashcode, tree type)
>
> /* The TYPE_ALIGN field of a type is set by layout_type(), so we
> must call that routine before comparing TYPE_ALIGNs. */
> - layout_type (type);
> + if (TREE_CODE (type) < NUM_TREE_CODES)
> + layout_type (type);
>
> in.hash = hashcode;
> in.type = type;
I think that can't be sufficient, because type_cache_hasher::equal
has:
switch (TREE_CODE (a->type))
{
...
default:
return 0;
}
if (lang_hooks.types.type_hash_eq != NULL)
return lang_hooks.types.type_hash_eq (a->type, b->type);
return 1;
}
so for types it doesn't know about it will just always return 0.
Or is that what we want for the FE specific types?
Another possibility would be to return 0; for default only if
lang_hooks.types.type_hash_eq is NULL, and otherwise defer to
the langhook, plus changing the C++ and Ada langhooks to do
something with them if needed.
Jakub
