/* Multiple versions of strlen(str) -- determine the length of the string STR. All versions must be listed in ifunc-impl-list.c. Copyright (C) 2009-2013 Free Software Foundation, Inc. Contributed by Ulrich Drepper . 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 . */ #include #include /* Define multiple versions only for the definition in libc and for the DSO. In static binaries we need strlen before the initialization happened. */ #if defined SHARED && !defined NOT_IN_libc .text ENTRY(strlen) .type strlen, @gnu_indirect_function cmpl $0, __cpu_features+KIND_OFFSET(%rip) jne 1f call __init_cpu_features 1: leaq __strlen_sse2_pminub(%rip), %rax testl $bit_Prefer_PMINUB_for_stringop, __cpu_features+FEATURE_OFFSET+index_Prefer_PMINUB_for_stringop(%rip) jnz 2f leaq __strlen_sse2(%rip), %rax testl $bit_SSE4_2, __cpu_features+CPUID_OFFSET+index_SSE4_2(%rip) jz 2f leaq __strlen_sse42(%rip), %rax ret 2: testl $bit_Slow_BSF, __cpu_features+FEATURE_OFFSET+index_Slow_BSF(%rip) jz 3f leaq __strlen_sse2_no_bsf(%rip), %rax 3: ret END(strlen) # undef ENTRY # define ENTRY(name) \ .type __strlen_sse2, @function; \ .align 16; \ .globl __strlen_sse2; \ .hidden __strlen_sse2; \ __strlen_sse2: cfi_startproc; \ CALL_MCOUNT # undef END # define END(name) \ cfi_endproc; .size __strlen_sse2, .-__strlen_sse2 # undef libc_hidden_builtin_def /* It doesn't make sense to send libc-internal strlen calls through a PLT. The speedup we get from using SSE4.2 instruction is likely eaten away by the indirect call in the PLT. */ # define libc_hidden_builtin_def(name) \ .globl __GI_strlen; __GI_strlen = __strlen_sse2 #endif #include "../strlen.S"