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Re: [PATCH 3/4] split-stack for powerpc64
- From: Alan Modra <amodra at gmail dot com>
- To: "Lynn A. Boger" <laboger at linux dot vnet dot ibm dot com>
- Cc: gcc-patches at gcc dot gnu dot org, David Edelsohn <dje dot gcc at gmail dot com>
- Date: Wed, 20 May 2015 10:22:20 +0930
- Subject: Re: [PATCH 3/4] split-stack for powerpc64
- Authentication-results: sourceware.org; auth=none
- References: <20150518025451 dot GW6140 at bubble dot grove dot modra dot org> <555B2F2F dot 8030909 at linux dot vnet dot ibm dot com>
On Tue, May 19, 2015 at 07:40:15AM -0500, Lynn A. Boger wrote:
> Questions on the use of the options for split stack:
>
> - The way this is implemented, split stack is generated if the
> target platform supports split stack, on ppc64/ppc64le as well
> as on x86, and the use of -fno-split-stack doesn't seem to affect it
> for any of these. Is that the way it should work? I would expect
> -fno-split-stack to disable it completely.
Can you give a testcase to show what you mean? Picking one of the go
testsuite programs at random, I see
$ gcc/xgcc -Bgcc/ -S -I powerpc64le-linux/libgo /src/gcc-virgin/gcc/testsuite/go.test/test/args.go
$ grep morestack args.s
bl __morestack
bl __morestack
$ gcc/xgcc -Bgcc/ -fno-split-stack -S -I powerpc64le-linux/libgo /src/gcc-virgin/gcc/testsuite/go.test/test/args.go
$ grep morestack args.s
$
That shows -fno-split-stack being honoured.
> - The comments say that the gold linker is used for some
> situations but I don't see any reference in the code to enabling
> the gold linker for ppc64le, ppc64, or x86. Is the user expected
> to add the option for the gold linker if needed?
At the moment I believe this is true.
--
Alan Modra
Australia Development Lab, IBM