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Re: Turn on -fomit-frame-pointer by default for 32bit x86?
On Tue, Jul 13, 2010 at 11:44 PM, H.J. Lu <hjl.tools@gmail.com> 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.
We build opensuse with -fomit-frame-pointer -fasynchronous-unwind-tables.
If you want to make -fomit-frame-pointer the default then you should enable
unwind tables by default.
Richard.
>
> --
> H.J.
>