Re: [PATCH][aarch64] Enable ifunc resolver attribute by default

[Szabolcs Nagy <szabolcs dot nagy at arm dot com>]

On 05/09/17 18:09, Steve Ellcey wrote:
> On Mon, 2017-09-04 at 15:40 +0100, Szabolcs Nagy wrote:
> 
>> this is not the right default for bionic, uclibc and musl
>>
>> (gcc does not distinguish between supporting ifunc in the
>> compiler vs runtime, so when ifunc is enabled it is assumed
>> the c runtime will have support too, hence libatomic and
>> libgcc starts using ifuncs which breaks at runtime)
>>
>> so don't change the default if target matches
>> *-*-*android*|*-*-*uclibc*|*-*-*musl*)
>>
>> (i think the default should be kept "no" for these targets
>> independently of cpu arch, so the current logic that is
>> repeated many places in config.gcc is suboptimal.
> 
> I cleaned up config.gcc so default_gnu_indirect_function is set in a
> single place now and has the right defaults for android/uclibc/musl.
> 

thanks, it looks ok to me (but i cannot approve the patch).

>> and i think the attribute syntax should be always supported
>> and this setting should only mean that ifunc use is allowed
>> in the runtime libraries.)
> 
> I think that might be a reasonable thing to do but should be a
> separate patch from this change, so I have not done anything
> with that.
> 
> I retested on aarch64 but I did not test any of the other platforms
> where I moved the setting of default_gnu_indirect_function, but I
> don't think I changed any defaults.
> 
> Steve Ellcey
> sellcey@cavium.com
> 
> 
> 2017-09-05  Steve Ellcey  <sellcey@cavium.com>
> 
>         * config.gcc: Add new case statement to set
>         default_gnu_indirect_function.  Remove it from x86_64-*-linux*,
>         i[34567]86-*, powerpc*-*-linux*spe*, powerpc*-*-linux*, s390-*-linux*,
>         s390x-*-linux* case statements.   Added aarch64 to the list of
>         supported architectures.
>