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

[David Laight]

From: Nathan Chancellor [mailto:natechancellor at gmail.com]
> Sent: 04 September 2019 01:24
> On Tue, Sep 03, 2019 at 02:31:28PM -0500, Segher Boessenkool wrote:
> > On Mon, Sep 02, 2019 at 10:55:53PM -0700, Nathan Chancellor wrote:
> > > On Thu, Aug 29, 2019 at 09:59:48AM +0000, David Laight wrote:
> > > > From: Nathan Chancellor
> > > > > Sent: 28 August 2019 19:45
> > > > ...
> > > > > 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.
> > > >
> > > > Isn't implementing setjmp impossible unless you tell the compiler that
> > > > you function is 'setjmp-like' ?
> > >
> > > No idea, PowerPC is the only architecture that does such a thing.
> >
> > Since setjmp can return more than once, yes, exciting things can happen
> > if you do not tell the compiler about this.
> >
> >
> > Segher
> >
> 
> Fair enough so I guess we are back to just outright disabling the
> warning.

Just disabling the warning won't stop the compiler generating code
that breaks a 'user' implementation of setjmp().

	David

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