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From: David Laight <David.Laight@ACULAB.COM>
To: 'Nathan Chancellor' <natechancellor@gmail.com>,
	Segher Boessenkool <segher@kernel.crashing.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"# 3.4.x" <stable@vger.kernel.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>,
	Paul Mackerras <paulus@samba.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: RE: [PATCH] powerpc: Avoid clang warnings around setjmp and longjmp
Date: Wed, 4 Sep 2019 08:16:45 +0000	[thread overview]
Message-ID: <1bcd7086f3d24dfa82eec03980f30fbc@AcuMS.aculab.com> (raw)
In-Reply-To: <20190904002401.GA70635@archlinux-threadripper>

From: Nathan Chancellor [mailto:natechancellor@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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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)


  reply	other threads:[~2019-09-04  8:18 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-12  2:32 [PATCH] powerpc: Avoid clang warnings around setjmp and longjmp Nathan Chancellor
2019-08-12  5:37 ` Christophe Leroy
2019-08-12 16:55   ` Nathan Chancellor
2019-08-12 17:35 ` Nick Desaulniers
2019-08-27  0:12 ` Nathan Chancellor
2019-08-28 13:43 ` Michael Ellerman
2019-08-28 17:53   ` Nathan Chancellor
2019-08-28 18:01     ` Nick Desaulniers
2019-08-28 18:45       ` Nathan Chancellor
2019-08-28 22:16         ` Nick Desaulniers
2019-08-29  8:32           ` Segher Boessenkool
2019-08-29  9:59         ` David Laight
2019-09-03  5:55           ` Nathan Chancellor
2019-09-03 19:31             ` Segher Boessenkool
2019-09-04  0:24               ` Nathan Chancellor
2019-09-04  8:16                 ` David Laight [this message]
2019-09-04 13:01                   ` Segher Boessenkool
2019-09-04 23:15                     ` Nathan Chancellor
2019-09-10 18:30                       ` Michael Ellerman
2019-09-10 18:37                         ` Nathan Chancellor

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