From: David Laight <David.Laight@ACULAB.COM>
To: 'Nathan Chancellor' <natechancellor@gmail.com>,
Nick Desaulniers <ndesaulniers@google.com>
Cc: 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: Thu, 29 Aug 2019 09:59:48 +0000 [thread overview]
Message-ID: <6801a83ed6d54d95b87a41c57ef6e6b0@AcuMS.aculab.com> (raw)
In-Reply-To: <20190828184529.GC127646@archlinux-threadripper>
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' ?
For instance I think it all goes horribly wrong if the generated code
looks like:
push local_variable
// setup arguments to setjmp
call setjmp
pop local_variable
// check return value of setjmp
With a naive compiler and simple ABI setjmp just has to save the
return address, stack pointer and caller saved registers.
With modern compilers and ABI I doubt you can implement setjmp
without some help from the compiler.
It is probably best to avoid setjmp/longjmp completely.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2019-08-29 14:08 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 [this message]
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
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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