Re: [PATCH] powerpc: Avoid clang warnings around setjmp and longjmp

[Nick Desaulniers <ndesaulniers@google.com>]

On Wed, Aug 28, 2019 at 11:45 AM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> On Wed, Aug 28, 2019 at 11:01:14AM -0700, Nick Desaulniers wrote:
> > On Wed, Aug 28, 2019 at 10:53 AM Nathan Chancellor
> > <natechancellor@gmail.com> wrote:
> > >
> > > Yes, I don't think this would be unreasonable. Are you referring to the
> > > cc-disable-warning flags or the -fno-builtin flags? I personally think
> > > the -fno-builtin flags convey to clang what the kernel is intending to
> > > do better than disabling the warnings outright.
> >
> > The `-f` family of flags have dire implications for codegen, I'd
> > really prefer we think long and hard before adding/removing them to
> > suppress warnings.  I don't think it's a solution for this particular
> > problem.
>
> I am fine with whatever approach gets this warning fixed to the
> maintainer's satisfaction...
>
> However, I think that -fno-builtin-* would be appropriate here because
> we are providing our own setjmp implementation, meaning clang should not
> be trying to do anything with the builtin implementation like building a
> declaration for it.

That's a good reason IMO.  IIRC, the -fno-builtin-* flags don't warn
if * is some unrecognized value, so -fno-builtin-setjmp may not
actually do anything, and you may need to scan the source (of clang or
llvm).

-- 
Thanks,
~Nick Desaulniers