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Date: Wed, 14 Jul 2010 12:00:00 -0000
From: Dave Korn <dave.korn.cygwin@gmail.com>
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To: "H.J. Lu" <hjl.tools@gmail.com>
CC: Andrew Pinski <pinskia@gmail.com>,  Richard Guenther <richard.guenther@gmail.com>, GCC Patches <gcc-patches@gcc.gnu.org>, Uros Bizjak <ubizjak@gmail.com>
Subject: Re: Turn on -fomit-frame-pointer by default for 32bit x86?
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On 13/07/2010 22:44, H.J. Lu wrote:
> On Tue, Jul 13, 2010 at 2:02 PM, Andrew Pinski <pinskia@gmail.com> wrote:
>> On Tue, Jul 13, 2010 at 2:01 PM, Andrew Pinski <pinskia@gmail.com> wrote:
>>> On Tue, Jul 13, 2010 at 1:59 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>> What will stop working when -fomit-frame-pointer is on?
>>> backtraces when debugging information is not turned on.
>> See http://gcc.gnu.org/ml/gcc-patches/2004-08/msg01033.html and many
>> more.  This is not the first time this has been discussed.
> 
> Most of 32bit x86 assembly codes in glibc have .eh_frame section.
> If backtrace is absolutely needed, they can add -fasynchronous-unwind-tables
> or -fno-omit-frame-pointer.
> 

  Alas not all the x86 world is a glibc.  So if you want to do this it has to
be target-dependent I think.

    cheers,
      DaveK