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Implement SSE4.2 optimized strchr and strrchr.

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H.J. Lu 2009-10-22 22:47:12 -07:00 committed by Ulrich Drepper
parent 31ba3e7a7d
commit 001659f4d5
5 changed files with 514 additions and 1 deletions
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8
ChangeLog
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@ -1,3 +1,11 @@
2009-10-21 H.J. Lu <hongjiu.lu@intel.com>
* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
strend-sse4.
* sysdeps/x86_64/multiarch/strchr.S: New file.
* sysdeps/x86_64/multiarch/strend-sse4.S: New file.
* sysdeps/x86_64/multiarch/strrchr.S: New file.
2009-10-21 Andreas Schwab <schwab@redhat.com>
* elf/dl-sym.c (do_sym): Resolve STT_GNU_IFUNC symbols.

3
sysdeps/x86_64/multiarch/Makefile
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@ -4,7 +4,8 @@ gen-as-const-headers += ifunc-defines.sym
endif
ifeq ($(subdir),string)
sysdep_routines += stpncpy-c strncpy-c strcmp-ssse3 strncmp-ssse3
sysdep_routines += stpncpy-c strncpy-c strcmp-ssse3 strncmp-ssse3 \
strend-sse4
ifeq (yes,$(config-cflags-sse4))
sysdep_routines += strcspn-c strpbrk-c strspn-c strstr-c strcasestr-c
CFLAGS-strcspn-c.c += -msse4

177
sysdeps/x86_64/multiarch/strchr.S Normal file
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@ -0,0 +1,177 @@
/* strchr with SSE4.2
Copyright (C) 2009 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sysdep.h>
#include <ifunc-defines.h>
/* Define multiple versions only for the definition in libc. */
#ifndef NOT_IN_libc
.text
ENTRY(strchr)
.type strchr, @gnu_indirect_function
cmpl $0, __cpu_features+KIND_OFFSET(%rip)
jne 1f
call __init_cpu_features
1: leaq __strchr_sse2(%rip), %rax
testl $(1<<20), __cpu_features+CPUID_OFFSET+COMMON_CPUID_INDEX_1*CPUID_SIZE+CPUID_ECX_OFFSET(%rip)
jz 2f
leaq __strchr_sse42(%rip), %rax
2: ret
END(strchr)
/*
This implementation uses SSE4 instructions to compare up to 16 bytes
at a time looking for the first occurrence of the character c in the
string s:
char *strchr (const char *s, int c);
We use 0xa:
_SIDD_SBYTE_OPS
| _SIDD_CMP_EQUAL_EACH
| _SIDD_LEAST_SIGNIFICANT
on pcmpistri to compare xmm/mem128
0 1 2 3 4 5 6 7 8 9 A B C D E F
X X X X X X X X X X X X X X X X
against xmm
0 1 2 3 4 5 6 7 8 9 A B C D E F
C C C C C C C C C C C C C C C C
to find out if the first 16byte data element has a byte C and the
offset of the first byte. There are 3 cases:
1. The first 16byte data element has the byte C at the offset X.
2. The first 16byte data element has EOS and doesn't have the byte C.
3. The first 16byte data element is valid and doesn't have the byte C.
Here is the table of ECX, CFlag, ZFlag and SFlag for 3 cases:
case ECX CFlag ZFlag SFlag
1 X 1 0/1 0
2 16 0 1 0
3 16 0 0 0
We exit from the loop for cases 1 and 2 with jbe which branches
when either CFlag or ZFlag is 1. If CFlag == 1, ECX has the offset
X for case 1. */
.section .text.sse4.2,"ax",@progbits
.align 16
.type __strchr_sse42, @function
__strchr_sse42:
cfi_startproc
CALL_MCOUNT
testb %sil, %sil
je __strend_sse4
pxor %xmm2, %xmm2
movd %esi, %xmm1
movl %edi, %ecx
andl $15, %ecx
movq %rdi, %r8
je L(aligned_start)
/* Handle unaligned string. */
andq $-16, %r8
pshufb %xmm2, %xmm1
movdqa (%r8), %xmm0
pcmpeqb %xmm0, %xmm2
pcmpeqb %xmm1, %xmm0
/* Find where NULL is. */
pmovmskb %xmm2, %edx
/* Check if there is a match. */
pmovmskb %xmm0, %esi
/* Remove the leading bytes. */
sarl %cl, %edx
sarl %cl, %esi
testl %esi, %esi
je L(unaligned_no_match)
/* Check which byte is a match. */
bsfl %esi, %eax
/* Is there a NULL? */
testl %edx, %edx
je L(unaligned_match)
bsfl %edx, %esi
cmpl %esi, %eax
/* Return NULL if NULL comes first. */
ja L(return_null)
L(unaligned_match):
addq %rdi, %rax
ret
.p2align 4
L(unaligned_no_match):
testl %edx, %edx
jne L(return_null)
/* Loop start on aligned string. */
L(loop):
addq $16, %r8
L(aligned_start):
pcmpistri $0x2, (%r8), %xmm1
jbe L(wrap)
addq $16, %r8
pcmpistri $0x2, (%r8), %xmm1
jbe L(wrap)
addq $16, %r8
pcmpistri $0x2, (%r8), %xmm1
jbe L(wrap)
addq $16, %r8
pcmpistri $0x2, (%r8), %xmm1
jbe L(wrap)
jmp L(loop)
L(wrap):
jc L(loop_exit)
/* Return NULL. */
L(return_null):
xorl %eax, %eax
ret
/* Loop exit. */
.p2align 4
L(loop_exit):
leaq (%r8,%rcx), %rax
ret
cfi_endproc
.size __strchr_sse42, .-__strchr_sse42
# undef ENTRY
# define ENTRY(name) \
.type __strchr_sse2, @function; \
.align 16; \
__strchr_sse2: cfi_startproc; \
CALL_MCOUNT
# undef END
# define END(name) \
cfi_endproc; .size __strchr_sse2, .-__strchr_sse2
# undef libc_hidden_builtin_def
/* It doesn't make sense to send libc-internal strchr 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_strchr; __GI_strchr = __strchr_sse2
#endif
#include "../strchr.S"

49
sysdeps/x86_64/multiarch/strend-sse4.S Normal file
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@ -0,0 +1,49 @@
/* Return the pointer to the end of string, using SSE4.2
Copyright (C) 2009 Free Software Foundation, Inc.
Contributed by Intel Corporation.
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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sysdep.h>
#include "asm-syntax.h"
.section .text.sse4.2,"ax",@progbits
ENTRY (__strend_sse4)
pxor %xmm2, %xmm2
movq %rdi, %rcx
andq $~15, %rdi
movdqa %xmm2, %xmm1
pcmpeqb (%rdi), %xmm2
orl $0xffffffff, %esi
subq %rdi, %rcx
shll %cl, %esi
pmovmskb %xmm2, %edx
andl %esi, %edx
jnz 1f
2: pcmpistri $0x08, 16(%rdi), %xmm1
leaq 16(%rdi), %rdi
jnz 2b
leaq (%rdi,%rcx), %rax
ret
1: bsfl %edx, %eax
addq %rdi, %rax
ret
END (__strend_sse4)

278
sysdeps/x86_64/multiarch/strrchr.S Normal file
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@ -0,0 +1,278 @@
/* strrchr with SSE4.2
Copyright (C) 2009 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sysdep.h>
#include <ifunc-defines.h>
/* Define multiple versions only for the definition in libc and for
the DSO. In static binaries we need strrchr before the initialization
happened. */
#if defined SHARED && !defined NOT_IN_libc
.text
ENTRY(strrchr)
.type strrchr, @gnu_indirect_function
cmpl $0, __cpu_features+KIND_OFFSET(%rip)
jne 1f
call __init_cpu_features
1: leaq __strrchr_sse2(%rip), %rax
testl $(1<<20), __cpu_features+CPUID_OFFSET+COMMON_CPUID_INDEX_1*CPUID_SIZE+CPUID_ECX_OFFSET(%rip)
jz 2f
leaq __strrchr_sse42(%rip), %rax
2: ret
END(strrchr)
/*
This implementation uses SSE4 instructions to compare up to 16 bytes
at a time looking for the last occurrence of the character c in the
string s:
char *strrchr (const char *s, int c);
We use 0x4a:
_SIDD_SBYTE_OPS
| _SIDD_CMP_EQUAL_EACH
| _SIDD_MOST_SIGNIFICANT
on pcmpistri to compare xmm/mem128
0 1 2 3 4 5 6 7 8 9 A B C D E F
X X X X X X X X X X X X X X X X
against xmm
0 1 2 3 4 5 6 7 8 9 A B C D E F
C C C C C C C C C C C C C C C C
to find out if the first 16byte data element has a byte C and the
last offset. There are 4 cases:
1. The first 16byte data element has EOS and has the byte C at the
last offset X.
2. The first 16byte data element is valid and has the byte C at the
last offset X.
3. The first 16byte data element has EOS and doesn't have the byte C.
4. The first 16byte data element is valid and doesn't have the byte C.
Here is the table of ECX, CFlag, ZFlag and SFlag for 3 cases:
case ECX CFlag ZFlag SFlag
1 X 1 1 0
2 X 1 0 0
3 16 0 1 0
4 16 0 0 0
We exit from the loop for cases 1 and 3 with jz which branches
when ZFlag is 1. If CFlag == 1, ECX has the offset X for case 1. */
.section .text.sse4.2,"ax",@progbits
.align 16
.type __strrchr_sse42, @function
__strrchr_sse42:
cfi_startproc
CALL_MCOUNT
testb %sil, %sil
je __strend_sse4
xor %eax,%eax /* RAX has the last occurrence of s. */
movd %esi, %xmm1
punpcklbw %xmm1, %xmm1
movl %edi, %esi
punpcklbw %xmm1, %xmm1
andl $15, %esi
pshufd $0, %xmm1, %xmm1
movq %rdi, %r8
je L(loop)
/* Handle unaligned string using psrldq. */
leaq L(psrldq_table)(%rip), %rdx
andq $-16, %r8
movslq (%rdx,%rsi,4),%r9
movdqa (%r8), %xmm0
addq %rdx, %r9
jmp *%r9
/* Handle unaligned string with offset 1 using psrldq. */
.p2align 4
L(psrldq_1):
psrldq $1, %xmm0
.p2align 4
L(unaligned_pcmpistri):
pcmpistri $0x4a, %xmm1, %xmm0
jnc L(unaligned_no_byte)
leaq (%rdi,%rcx), %rax
L(unaligned_no_byte):
/* Find the length of the unaligned string. */
pcmpistri $0x3a, %xmm0, %xmm0
movl $16, %edx
subl %esi, %edx
cmpl %ecx, %edx
/* Return RAX if the unaligned fragment to next 16B already
contain the NULL terminator. */
jg L(exit)
addq $16, %r8
/* Loop start on aligned string. */
.p2align 4
L(loop):
pcmpistri $0x4a, (%r8), %xmm1
jbe L(match_or_eos)
addq $16, %r8
jmp L(loop)
.p2align 4
L(match_or_eos):
je L(had_eos)
L(match_no_eos):
leaq (%r8,%rcx), %rax
addq $16, %r8
jmp L(loop)
.p2align 4
L(had_eos):
jnc L(exit)
leaq (%r8,%rcx), %rax
.p2align 4
L(exit):
ret
/* Handle unaligned string with offset 15 using psrldq. */
.p2align 4
L(psrldq_15):
psrldq $15, %xmm0
jmp L(unaligned_pcmpistri)
/* Handle unaligned string with offset 14 using psrldq. */
.p2align 4
L(psrldq_14):
psrldq $14, %xmm0
jmp L(unaligned_pcmpistri)
/* Handle unaligned string with offset 13 using psrldq. */
.p2align 4
L(psrldq_13):
psrldq $13, %xmm0
jmp L(unaligned_pcmpistri)
/* Handle unaligned string with offset 12 using psrldq. */
.p2align 4
L(psrldq_12):
psrldq $12, %xmm0
jmp L(unaligned_pcmpistri)
/* Handle unaligned string with offset 11 using psrldq. */
.p2align 4
L(psrldq_11):
psrldq $11, %xmm0
jmp L(unaligned_pcmpistri)
/* Handle unaligned string with offset 10 using psrldq. */
.p2align 4
L(psrldq_10):
psrldq $10, %xmm0
jmp L(unaligned_pcmpistri)
/* Handle unaligned string with offset 9 using psrldq. */
.p2align 4
L(psrldq_9):
psrldq $9, %xmm0
jmp L(unaligned_pcmpistri)
/* Handle unaligned string with offset 8 using psrldq. */
.p2align 4
L(psrldq_8):
psrldq $8, %xmm0
jmp L(unaligned_pcmpistri)
/* Handle unaligned string with offset 7 using psrldq. */
.p2align 4
L(psrldq_7):
psrldq $7, %xmm0
jmp L(unaligned_pcmpistri)
/* Handle unaligned string with offset 6 using psrldq. */
.p2align 4
L(psrldq_6):
psrldq $6, %xmm0
jmp L(unaligned_pcmpistri)
/* Handle unaligned string with offset 5 using psrldq. */
.p2align 4
L(psrldq_5):
psrldq $5, %xmm0
jmp L(unaligned_pcmpistri)
/* Handle unaligned string with offset 4 using psrldq. */
.p2align 4
L(psrldq_4):
psrldq $4, %xmm0
jmp L(unaligned_pcmpistri)
/* Handle unaligned string with offset 3 using psrldq. */
.p2align 4
L(psrldq_3):
psrldq $3, %xmm0
jmp L(unaligned_pcmpistri)
/* Handle unaligned string with offset 2 using psrldq. */
.p2align 4
L(psrldq_2):
psrldq $2, %xmm0
jmp L(unaligned_pcmpistri)
cfi_endproc
.size __strrchr_sse42, .-__strrchr_sse42
.section .rodata.sse4.2,"a",@progbits
.p2align 4
L(psrldq_table):
.int L(loop) - L(psrldq_table)
.int L(psrldq_1) - L(psrldq_table)
.int L(psrldq_2) - L(psrldq_table)
.int L(psrldq_3) - L(psrldq_table)
.int L(psrldq_4) - L(psrldq_table)
.int L(psrldq_5) - L(psrldq_table)
.int L(psrldq_6) - L(psrldq_table)
.int L(psrldq_7) - L(psrldq_table)
.int L(psrldq_8) - L(psrldq_table)
.int L(psrldq_9) - L(psrldq_table)
.int L(psrldq_10) - L(psrldq_table)
.int L(psrldq_11) - L(psrldq_table)
.int L(psrldq_12) - L(psrldq_table)
.int L(psrldq_13) - L(psrldq_table)
.int L(psrldq_14) - L(psrldq_table)
.int L(psrldq_15) - L(psrldq_table)
# undef ENTRY
# define ENTRY(name) \
.type __strrchr_sse2, @function; \
.align 16; \
__strrchr_sse2: cfi_startproc; \
CALL_MCOUNT
# undef END
# define END(name) \
cfi_endproc; .size __strrchr_sse2, .-__strrchr_sse2
# undef libc_hidden_builtin_def
/* It doesn't make sense to send libc-internal strrchr 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_strrchr; __GI_strrchr = __strrchr_sse2
#endif
#include "../strrchr.S"