[PATCH] Don't use PLT nor GOT in libc.a [BZ #20750]

[Florian Weimer]

On 11/04/2016 08:25 PM, H.J. Lu wrote:
> On Fri, Nov 4, 2016 at 12:03 PM, Florian Weimer <fweimer@redhat.com> wrote:
>> On 11/04/2016 06:47 PM, H.J. Lu wrote:
>>>
>>> There is no need to use PLT nor GOT in libc.a to branch to a function,
>>> regardless whether libc.a is compiled with PIC or not.
>>>
>>> Tested on x86-64.  OK for master?
>>
>>
>> Isn't this header file used outside of libc as well?
>
> It is used for other .a files.  If they aren't used to create static binaries,
> PLT/GOT may be used.  The resulting executable will work correctly.

You mean because “name” is automatically mapped to “name@plt”?

I find this comment not very illuminating:

+/* For libc.a, we want to branch to target directly.  */
  # define JUMPTARGET(name)	name

And cheating the static linker in this way seems like a future 
maintenance hazard.

Thanks,
Florian