Re: [PATCH v2] Compiler Attributes: Add __counted_by macro

[Fangrui Song]

On Fri, May 26, 2023 at 11:56 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>
> On Fri, May 26, 2023 at 07:47:03PM +0200, Miguel Ojeda wrote:
> > On Fri, May 26, 2023 at 7:16 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> > >
> > > FYI, applied to for-next/hardening:
> > >
> > > [1/1] Compiler Attributes: Add __counted_by macro
> > >       https://git.kernel.org/kees/c/86a76e91cbab
> >
> > Sorry, I was going to apply it soon -- in case you want it:
> >
> >     Acked-by: Miguel Ojeda <ojeda@xxxxxxxxxx>
>
> Thanks!
>
> > And thanks Nathan for resubmitting the `Reviewed-by` from v1!
>
> Yes, apologies for missing this in my v2 submission!
>
> --
> Kees Cook
>

https://discourse.llvm.org/t/rfc-enforcing-bounds-safety-in-c-fbounds-safety/70854
proposes a macro __counted_by as well.
This patch uses the same name:

> # define __counted_by(member)          __attribute__((__element_count__(member)))

I wonder whether the two use cases are compatible so that using the
same macro name will be fine.

#if defined(__has_feature) && __has_feature(bounds_safety)
#define __counted_by(T) __attribute__((__counted_by__(T)))
// ... other bounds annotations
#else
#define __counted_by(T) // defined as nothing // ... other bounds annotations
#endif


-- 
宋方睿