[PATCH] x86-64: Implement memcmp family IFUNC selectors in C

[Adhemerval Zanella]

On 12/06/2017 13:10, H.J. Lu wrote:
> Implement memcmp family IFUNC selectors in C.
> 
> All internal calls within libc.so can use IFUNC on x86-64 since unlike
> x86, x86-64 supports PC-relative addressing to access the GOT entry so
> that it can call via PLT without using an extra register.  For libc.a,
> we can't use IFUNC for functions which are called before IFUNC has been
> initialized.  Use IFUNC internally reduces the icache footprint since
> libc.so and other codes in the process use the same implementations.
> This patch uses IFUNC for memcmp family functions within libc.
> 
> Any comments?
> 
> H.J.
> ---
> 2017-06-07  H.J. Lu  <hongjiu.lu@intel.com>
> 	    Erich Elsen  <eriche@google.com>
> 
> 	* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
> 	memcmp-sse2.
> 	* sysdeps/x86_64/multiarch/ifunc-memcmp.h: New file.
> 	* sysdeps/x86_64/multiarch/memcmp-sse2.S: Likewise.
> 	* sysdeps/x86_64/multiarch/memcmp.c: Likewise.
> 	* sysdeps/x86_64/multiarch/wmemcmp.c: Likewise.
> 	* sysdeps/x86_64/multiarch/memcmp.S: Removed.
> 	* sysdeps/x86_64/multiarch/wmemcmp.S: Likewise.

LGTM.