Re: PATCH: PR corefiles/11481: gcore doesn't work on i386 without SSE

[Mark Kettenis <mark.kettenis@xs4all.nl>]

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> Date: Sat, 10 Apr 2010 08:46:04 -0700
> From: "H.J. Lu" <hjl.tools@gmail.com>
> 
> On Sat, Apr 10, 2010 at 7:49 AM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> >> Date: Fri, 9 Apr 2010 13:43:06 -0700
> >> From: "H.J. Lu" <hjl.tools@gmail.com>
> >>
> >> On Fri, Apr 9, 2010 at 1:08 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> >> > On Fri, Apr 9, 2010 at 12:15 PM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> >> >>> Date: Fri, 9 Apr 2010 09:01:01 -0700
> >> >>> From: "H.J. Lu" <hjl.tools@gmail.com>
> >> >>>
> >> >>> On Fri, Apr 9, 2010 at 8:59 AM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> >> >>> >> Date: Fri, 9 Apr 2010 08:50:12 -0700
> >> >>> >> From: "H.J. Lu" <hongjiu.lu@intel.com>
> >> >>> >>
> >> >>> >> Hi,
> >> >>> >>
> >> >>> >> This patch fixes gcore by not generating core regset sections which
> >> >>> >> aren't supported by i386 without SSE.  OK to install?
> >> >>> >
> >> >>> > Sorry, I think this is the wrong way to fix this.
> >> >>> >
> >> >>>
> >> >>> Any suggestions?
> >> >>
> >> >> Yup.  This makes sure we always install a list of register notes that
> >> >> matches the target description.
> >> >>
> >> >> 2010-04-09  Mark Kettenis  <kettenis@gnu.org>
> >> >>
> >> >>        * i386-linux-tdep.c (i386_linux_regset_sections): Remove extended
> >> >>        register note sections.
> >> >>        (i386_linux_sse_regset_sections, i386_linux_avx_regset_sections):
> >> >>        New variables.
> >> >>        (i386_linux_init_abi): Install list of supported register note
> >> >>        sections that matches the target description.
> >> >>
> >> >
> >> > That is nice. We should do the same thing in amd64-linux-tdep.c.
> >> >
> >>
> >> My second thought. No need to change amd64-linux-tdep.c.
> >> We can just add i386_linux_mmx_regset_sections. OK to install?
> >
> > Why should we do it this way?
> >
> 
> It will be nice for "gcore" to generate all valid note sections
> so that the older gdb can still exam the core generated by
> the newer gdb even if the older gdb may not access the
> new registers it doesn't support. Otherwise, gdb 7.0
> can't see any XMM registers in coredump generated
> by gdb 7.2 on AVX machine even if the upper 128bits
> of YMM registers are never used.

Thought about this for a bit, but I think it is better not to include
those registers at all than to generate core dumps where half the
register appears to be "lost".

So I committed my origional diff, and I'll change amd64-linux-tdep.c
to match the i386 behaviour.