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Re: [PATCH] x86-64: Implement strcspn/strpbrk/strspn IFUNC selectors in C
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Thu, 15 Jun 2017 12:35:28 -0300
- Subject: Re: [PATCH] x86-64: Implement strcspn/strpbrk/strspn IFUNC selectors in C
- Authentication-results: sourceware.org; auth=none
- References: <20170612161239.GF25262@gmail.com>
On 12/06/2017 13:12, H.J. Lu wrote:
> Implement strcspn/strpbrk/strspn 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 strcspn/strpbrk/strspn functions within libc.
> Any comments?
> * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
> strcspn-sse2, strpbrk-sse2 and strspn-sse2.
> * sysdeps/x86_64/strcspn.S (STRPBRK_P): Removed.
> Check USE_AS_STRPBRK instead of STRPBRK_P.
> * sysdeps/x86_64/strpbrk.S (USE_AS_STRPBRK): New.
> * sysdeps/x86_64/multiarch/ifunc-sse4_2.h: New file.
> * sysdeps/x86_64/multiarch/strcspn-sse2.S: Likewise.
> * sysdeps/x86_64/multiarch/strcspn.c: Likewise.
> * sysdeps/x86_64/multiarch/strpbrk-sse2.S: Likewise.
> * sysdeps/x86_64/multiarch/strpbrk.c: Likewise.
> * sysdeps/x86_64/multiarch/strspn-sse2.S: Likewise.
> * sysdeps/x86_64/multiarch/strspn.c: Likewise.
> * sysdeps/x86_64/multiarch/strcspn.S: Removed.
> * sysdeps/x86_64/multiarch/strpbrk.S: Likewise.
> * sysdeps/x86_64/multiarch/strspn.S: Likewise.
> * sysdeps/x86_64/multiarch/strpbrk-c.c: Remove "#ifdef SHARED"
> and "#endif".