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From: David Laight <David.Laight@ACULAB.COM>
To: 'Michael Ellerman' <patch-notifications@ellerman.id.au>,
	Joel Stanley <joel@jms.id.au>,
	"Naveen N . Rao" <naveen.n.rao@linux.vnet.ibm.com>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Subject: RE: powerpc/xmon: Relax frame size for clang
Date: Fri, 2 Nov 2018 10:26:57 +0000	[thread overview]
Message-ID: <1d9525b6fc9b48c0971201ddb5f5dc12@AcuMS.aculab.com> (raw)
In-Reply-To: <42m4hs6PHXzB4XV@ozlabs.org>

From: Linuxppc-dev [mailto:linuxppc-dev-bounces+david.laight=aculab.com@lists.ozlabs.org] On Behalf Of
> Michael Ellerman
> Subject: Re: powerpc/xmon: Relax frame size for clang
> 
> On Wed, 2018-10-31 at 01:09:34 UTC, Joel Stanley wrote:
> > When building with clang (8 trunk, 7.0 release) the frame size limit is
> > hit:
> >
> >  arch/powerpc/xmon/xmon.c:452:12: warning: stack frame size of 2576
> >  bytes in function 'xmon_core' [-Wframe-larger-than=]
> >
> > Some investigation by Naveen indicates this is due to clang saving the
> > addresses to printf format strings on the stack.
> >
> > While this issue is investigated, bump up the frame size limit for xmon
> > when building with clang.
> >
> > Link: https://github.com/ClangBuiltLinux/linux/issues/252
> > Signed-off-by: Joel Stanley <joel@jms.id.au>

Would it be better to stop some of the functions being inlined?

Clearly clang shouldn't be using separate on-stack temporaries
for every printf() call.
That is indicative of a bigger problem.

	David

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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)


      reply	other threads:[~2018-11-02 14:29 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-31  1:09 [PATCH] powerpc/xmon: Relax frame size for clang Joel Stanley
2018-11-01 12:46 ` Michael Ellerman
2018-11-02 10:26   ` David Laight [this message]

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