glibc/sysdeps/x86_64/strcmp.S
Noah Goldstein ceabdcd130 x86: Add support to build strcmp/strlen/strchr with explicit ISA level
1. Add default ISA level selection in non-multiarch/rtld
   implementations.

2. Add ISA level build guards to different implementations.
    - I.e strcmp-avx2.S which is ISA level 3 will only build if
      compiled ISA level <= 3. Otherwise there is no reason to
      include it as we will always use one of the ISA level 4
      implementations (strcmp-evex.S).

3. Refactor the ifunc selector and ifunc implementation list to use
   the ISA level aware wrapper macros that allow functions below the
   compiled ISA level (with a guranteed replacement) to be skipped.

Tested with and without multiarch on x86_64 for ISA levels:
{generic, x86-64-v2, x86-64-v3, x86-64-v4}

And m32 with and without multiarch.
2022-07-16 03:07:59 -07:00

32 lines
1.3 KiB
ArmAsm

/* strcmp dispatch for RTLD and non-multiarch build
Copyright (C) 1999-2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* Symbol = strcmp. */
#define DEFAULT_IMPL_V1 "multiarch/strcmp-sse2.S"
/* strcmp-sse2-unaligned.S is often faster than strcmp-sse42.S and
doesn't have the drawback of using the `pcmpstri` instruction
which can be very slow on some CPUs. */
#define DEFAULT_IMPL_V2 "multiarch/strcmp-sse2-unaligned.S"
#define DEFAULT_IMPL_V3 "multiarch/strcmp-avx2.S"
#define DEFAULT_IMPL_V4 "multiarch/strcmp-evex.S"
#include "isa-default-impl.h"
libc_hidden_builtin_def (strcmp)