1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
|
/* 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 <drepper@redhat.com>.
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
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <init-arch.h>
/* 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"
|
