[U-Boot] [RFC] x86: Do no use reparm as it break libgcc linkage

Graeme Russ graeme.russ at gmail.com
Thu Nov 10 06:10:41 CET 2011


Hi Mike,

On Thu, Nov 10, 2011 at 3:22 PM, Graeme Russ <graeme.russ at gmail.com> wrote:
> Hi Mike,
>
> On Thu, Nov 10, 2011 at 3:13 PM, Mike Frysinger <vapier at gentoo.org> wrote:
>> On Wednesday 09 November 2011 16:42:51 Graeme Russ wrote:
>>> On Thu, Nov 10, 2011 at 4:12 AM, Mike Frysinger wrote:
>>> > On Wednesday 09 November 2011 05:32:59 Graeme Russ wrote:
>>> >> --- a/arch/x86/config.mk
>>> >> +++ b/arch/x86/config.mk
>>> >>
>>> >> -PLATFORM_CPPFLAGS += -mregparm=3
>>> >> -PLATFORM_CPPFLAGS += -fomit-frame-pointer
>>> >
>>> > this sounds like you're throwing the baby out with the bath water.
>>> >  doesn't this severely affect the generated code ?
>>>
>>> No - omit-frame-pointer is enabled by -O2 and also:
>>>
>>> http://gcc.gnu.org/gcc-4.6/changes.html
>>>
>>> "The default setting (when not optimizing for size) for 32-bit
>>> GNU/Linux and Darwin x86 targets has been changed to
>>> -fomit-frame-pointer. The default can be reverted to
>>> -fno-omit-frame-pointer by configuring GCC with the
>>> --enable-frame-pointer configure option."
>>>
>>> So the flag is a do-nothing
>>
>> ok, except:
>>  - we build u-boot with -Os and not -O2
>>  - i'd say most people aren't using gcc-4.6

http://gcc.gnu.org/onlinedocs/gcc-4.6.2/gcc/Optimize-Options.html#Optimize-Options

-fomit-frame-pointer
...
Enabled at levels -O, -O2, -O3, -Os

Thats goes back to at least gcc 4.3.x

But I'll keep it in anyway, just in case someone wants to remove -Os
(for testing/debugging etc)

Regards,

Graeme


More information about the U-Boot mailing list