> On Mar 26, 2024, at 13:20, Joseph Myers <josmy...@redhat.com> wrote:
>
> On Tue, 26 Mar 2024, Qing Zhao wrote:
>
>>> What happens when there are multiple counted_by attributes on the same
>>> field? As far as I can see, all but one end up being ignored (by the code
>>> that actually uses the attribute).
>>
>> In general, is there any rule for handling multiple same attributes in
>> GCC? i.e, from left to right, the last one wins? Or something else? I’d
>> like to following the consistent rule with other places in GCC.
>
> Sometimes, they are meaningful and all can be respected. (An example is
> the format_arg attribute, where ngettext legitimately has two such
> attributes.)
>
> When not meaningful, an error is appropriate. For example, with section
> attributes you can get
>
> error ("section of %q+D conflicts with previous declaration",
> *node);
>
> if different sections are named. I think that's a suitable model for the
> new attribute here: allow duplicates if they name the same field, but give
> errors if they name different fields, just as with the section attribute.
>
> Once you give an error for multiple attributes naming different fields,
> which one wins is just a question of error recovery; the specific choice
> doesn't matter much, as long as you don't get an ICE in later processing.
Agreed and fixed as suggested.
Thanks.
Qing
>
> --
> Joseph S. Myers
> josmy...@redhat.com
