sysdeps/x86_64/multiarch/strchr.c

   1 /* Multiple versions of strchr.
   2    All versions must be listed in ifunc-impl-list.c.
   3    Copyright (C) 2009-2024 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 /* Define multiple versions only for the definition in libc.  */
  21 #if IS_IN (libc)
  22 # define strchr __redirect_strchr
  23 # include <string.h>
  24 # undef strchr
  25
  26 # define SYMBOL_NAME strchr
  27 # include <init-arch.h>
  28
  29 extern __typeof (REDIRECT_NAME) OPTIMIZE (evex) attribute_hidden;
  30
  31 extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
  32 extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_rtm) attribute_hidden;
  33
  34 extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
  35 extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2_no_bsf) attribute_hidden;
  36
  37 static inline void *
  38 IFUNC_SELECTOR (void)
  39 {
  40   const struct cpu_features *cpu_features = __get_cpu_features ();
  41
  42   if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX2)
  43       && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, BMI2)
  44       && X86_ISA_CPU_FEATURES_ARCH_P (cpu_features,
  45                                       AVX_Fast_Unaligned_Load, ))
  46     {
  47       if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
  48           && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512BW))
  49         return OPTIMIZE (evex);
  50
  51       if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
  52         return OPTIMIZE (avx2_rtm);
  53
  54       if (X86_ISA_CPU_FEATURES_ARCH_P (cpu_features,
  55                                        Prefer_No_VZEROUPPER, !))
  56         return OPTIMIZE (avx2);
  57     }
  58
  59   if (X86_ISA_CPU_FEATURES_ARCH_P (cpu_features, Slow_BSF, !))
  60     return OPTIMIZE (sse2);
  61
  62   return OPTIMIZE (sse2_no_bsf);
  63 }
  64
  65 libc_ifunc_redirected (__redirect_strchr, strchr, IFUNC_SELECTOR ());
  66 weak_alias (strchr, index)
  67 # ifdef SHARED
  68 __hidden_ver1 (strchr, __GI_strchr, __redirect_strchr)
  69   __attribute__((visibility ("hidden"))) __attribute_copy__ (strchr);
  70 # endif
  71 #endif