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Fix signedness in wcscmp comparison

This commit is contained in:
Liubov Dmitrieva 2011-10-23 13:34:15 -04:00 committed by Ulrich Drepper
parent 774a2669af
commit 95584d3b33
5 changed files with 239 additions and 132 deletions
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11
ChangeLog
View File

@ -1,3 +1,14 @@
2011-09-22 Liubov Dmitrieva <liubov.dmitrieva@gmail.com>
* sysdeps/x86_64/wcscmp.S: Update.
Fix wrong comparison semantics.
wcscmp shall use signed comparison not unsigned.
Don't use substraction to avoid overflow bug.
* sysdeps/i386/i686/multiarch/wcscmp-sse2.S: Likewise.
* wcsmbc/wcscmp.c: Likewise.
* string/test-strcmp.c: Likewise.
Add new tests to check cases with negative values.
2011-10-23 Ulrich Drepper <drepper@gmail.com>
* sysdeps/ieee754/dbl-64/dla.h: Move DLA_FMA definition to...

89
string/test-strcmp.c
View File

@ -1,4 +1,4 @@
/* Test and measure STRCMP functions.
/* Test and measure strcmp and wcscmp functions.
Copyright (C) 1999, 2002, 2003, 2005, 2011 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Written by Jakub Jelinek <jakub@redhat.com>, 1999.
@ -23,7 +23,6 @@
#include "test-string.h"
#ifdef WIDE
# include <inttypes.h>
# include <wchar.h>
# define L(str) L##str
@ -34,12 +33,53 @@
# define SIMPLE_STRCMP simple_wcscmp
# define STUPID_STRCMP stupid_wcscmp
# define CHAR wchar_t
# define UCHAR uint32_t
# define UCHAR wchar_t
# define CHARBYTES 4
# define CHARBYTESLOG 2
# define CHARALIGN __alignof__ (CHAR)
# define MIDCHAR 0x7fffffff
# define LARGECHAR 0xfffffffe
# define CHAR__MAX WCHAR_MAX
# define CHAR__MIN WCHAR_MIN
/* Wcscmp uses signed semantics for comparison, not unsigned */
/* Avoid using substraction since possible overflow */
int
simple_wcscmp (const wchar_t *s1, const wchar_t *s2)
{
wchar_t c1, c2;
do
{
c1 = *s1++;
c2 = *s2++;
if (c2 == L'\0')
return c1 - c2;
}
while (c1 == c2);
return c1 < c2 ? -1 : 1;
}
int
stupid_wcscmp (const wchar_t *s1, const wchar_t *s2)
{
size_t ns1 = wcslen (s1) + 1;
size_t ns2 = wcslen (s2) + 1;
size_t n = ns1 < ns2 ? ns1 : ns2;
int ret = 0;
wchar_t c1, c2;
while (n--) {
c1 = *s1++;
c2 = *s2++;
if ((ret = c1 < c2 ? -1 : c1 == c2 ? 0 : 1) != 0)
break;
}
return ret;
}
#else
# define L(str) str
# define STRCMP strcmp
@ -55,31 +95,35 @@
# define CHARALIGN 1
# define MIDCHAR 0x7f
# define LARGECHAR 0xfe
#endif
typedef int (*proto_t) (const CHAR *, const CHAR *);
# define CHAR__MAX CHAR_MAX
# define CHAR__MIN CHAR_MIN
/* Strcmp uses unsigned semantics for comparison. */
int
SIMPLE_STRCMP (const CHAR *s1, const CHAR *s2)
simple_strcmp (const char *s1, const char *s2)
{
int ret;
while ((ret = *(UCHAR *) s1 - *(UCHAR *) s2++) == 0 && *s1++);
while ((ret = *(unsigned char *) s1 - *(unsigned char*) s2++) == 0 && *s1++);
return ret;
}
int
STUPID_STRCMP (const CHAR *s1, const CHAR *s2)
stupid_strcmp (const char *s1, const char *s2)
{
size_t ns1 = STRLEN (s1) + 1;
size_t ns2 = STRLEN (s2) + 1;
size_t ns1 = strlen (s1) + 1;
size_t ns2 = strlen (s2) + 1;
size_t n = ns1 < ns2 ? ns1 : ns2;
int ret = 0;
while (n--)
if ((ret = *(UCHAR *) s1++ - *(UCHAR *) s2++) != 0)
if ((ret = *(unsigned char *) s1++ - *(unsigned char *) s2++) != 0)
break;
return ret;
}
#endif
typedef int (*proto_t) (const CHAR *, const CHAR *);
IMPL (STUPID_STRCMP, 1)
IMPL (SIMPLE_STRCMP, 1)
@ -276,14 +320,31 @@ check (void)
STRCPY(s1, L("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrs"));
STRCPY(s2, L("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijkLMNOPQRSTUV"));
/* Check correct working for negatives values */
s1[0] = 1;
s2[0] = 1;
s1[1] = 1;
s2[1] = 1;
s1[2] = -1;
s2[2] = 3;
s1[3] = 0;
s2[3] = -1;
/* Check possible overflow bug, actual more for wcscmp */
s1[7] = CHAR__MIN;
s2[7] = CHAR__MAX;
size_t l1 = STRLEN (s1);
size_t l2 = STRLEN (s2);
for (size_t i1 = 0; i1 < l1; i1++)
for (size_t i2 = 0; i2 < l2; i2++)
{
int exp_result = SIMPLE_STRCMP (s1 + i1, s2 + i2);
FOR_EACH_IMPL (impl, 0)
check_result (impl, s1 + i1, s2 + i2, exp_result);
int exp_result = SIMPLE_STRCMP (s1 + i1, s2 + i2);
FOR_EACH_IMPL (impl, 0)
check_result (impl, s1 + i1, s2 + i2, exp_result);
}
}

158
sysdeps/i386/i686/multiarch/wcscmp-sse2.S
View File

@ -21,7 +21,6 @@
#ifndef NOT_IN_libc
# include <sysdep.h>
# include "asm-syntax.h"
# define CFI_PUSH(REG) \
cfi_adjust_cfa_offset (4); \
@ -34,18 +33,16 @@
# define PUSH(REG) pushl REG; CFI_PUSH (REG)
# define POP(REG) popl REG; CFI_POP (REG)
# ifndef STRCMP
# define STRCMP __wcscmp_sse2
# endif
# define ENTRANCE PUSH(%esi); PUSH(%edi)
# define RETURN POP(%edi); POP(%esi); ret; CFI_PUSH(%esi); CFI_PUSH(%edi);
# define PARMS 4
# define STR1 PARMS
# define STR2 STR1+4
/* Note: wcscmp uses signed comparison, not unsugned as in strcmp function. */
.text
ENTRY (STRCMP)
ENTRY (__wcscmp_sse2)
/*
* This implementation uses SSE to compare up to 16 bytes at a time.
*/
@ -131,7 +128,7 @@ L(continue_48_48):
jne L(nequal)
test %ecx, %ecx
jz L(equal)
movdqu 16(%edi), %xmm1
movdqu 16(%esi), %xmm2
pcmpeqd %xmm1, %xmm0 /* Any null double_word? */
@ -264,21 +261,21 @@ L(continue_00_48):
test %ecx, %ecx
jnz L(less4_double_words1)
sub (%esi), %eax
jnz L(return)
cmp (%esi), %eax
jne L(nequal)
mov 4(%edi), %eax
sub 4(%esi), %eax
jnz L(return)
cmp 4(%esi), %eax
jne L(nequal)
mov 8(%edi), %eax
sub 8(%esi), %eax
jnz L(return)
cmp 8(%esi), %eax
jne L(nequal)
mov 12(%edi), %eax
sub 12(%esi), %eax
jnz L(return)
cmp 12(%esi), %eax
jne L(nequal)
movdqu 16(%esi), %xmm2
pcmpeqd %xmm2, %xmm0 /* Any null double_word? */
pcmpeqd 16(%edi), %xmm2 /* compare first 4 double_words for equality */
@ -381,7 +378,7 @@ L(continue_32_48):
movdqu 48(%esi), %xmm2
pcmpeqd %xmm1, %xmm0 /* Any null double_word? */
pcmpeqd %xmm2, %xmm1 /* compare first 4 double_words for equality */
psubb %xmm0, %xmm1 /* packed sub of comparison results*/
psubb %xmm0, %xmm1 /* packed sub of comparison results */
pmovmskb %xmm1, %edx
sub $0xffff, %edx /* if first 4 double_words are same, edx == 0xffff */
jnz L(less4_double_words_48)
@ -585,21 +582,21 @@ L(continue_48_00):
test %ecx, %ecx
jnz L(less4_double_words1)
sub (%esi), %eax
jnz L(return)
cmp (%esi), %eax
jne L(nequal)
mov 4(%edi), %eax
sub 4(%esi), %eax
jnz L(return)
cmp 4(%esi), %eax
jne L(nequal)
mov 8(%edi), %eax
sub 8(%esi), %eax
jnz L(return)
cmp 8(%esi), %eax
jne L(nequal)
mov 12(%edi), %eax
sub 12(%esi), %eax
jnz L(return)
cmp 12(%esi), %eax
jne L(nequal)
movdqu 16(%edi), %xmm1
pcmpeqd %xmm1, %xmm0 /* Any null double_word? */
pcmpeqd 16(%esi), %xmm1 /* compare first 4 double_words for equality */
@ -839,142 +836,161 @@ L(less4_double_words1):
test %ecx, %ecx
jz L(equal)
mov 12(%esi), %edx
mov 12(%edi), %eax
sub %edx, %eax
mov 12(%esi), %ecx
cmp %ecx, 12(%edi)
jne L(nequal)
xor %eax, %eax
RETURN
.p2align 4
L(less4_double_words):
xor %eax, %eax
test %dl, %dl
jz L(next_two_double_words)
and $15, %dl
jz L(second_double_word)
mov (%edi), %eax
sub (%esi), %eax
mov (%esi), %ecx
cmp %ecx, (%edi)
jne L(nequal)
RETURN
.p2align 4
L(second_double_word):
mov 4(%edi), %eax
sub 4(%esi), %eax
mov 4(%esi), %ecx
cmp %ecx, 4(%edi)
jne L(nequal)
RETURN
.p2align 4
L(next_two_double_words):
and $15, %dh
jz L(fourth_double_word)
mov 8(%edi), %eax
sub 8(%esi), %eax
mov 8(%esi), %ecx
cmp %ecx, 8(%edi)
jne L(nequal)
RETURN
.p2align 4
L(fourth_double_word):
mov 12(%edi), %eax
sub 12(%esi), %eax
mov 12(%esi), %ecx
cmp %ecx, 12(%edi)
jne L(nequal)
RETURN
.p2align 4
L(less4_double_words_16):
xor %eax, %eax
test %dl, %dl
jz L(next_two_double_words_16)
and $15, %dl
jz L(second_double_word_16)
mov 16(%edi), %eax
sub 16(%esi), %eax
mov 16(%esi), %ecx
cmp %ecx, 16(%edi)
jne L(nequal)
RETURN
.p2align 4
L(second_double_word_16):
mov 20(%edi), %eax
sub 20(%esi), %eax
mov 20(%esi), %ecx
cmp %ecx, 20(%edi)
jne L(nequal)
RETURN
.p2align 4
L(next_two_double_words_16):
and $15, %dh
jz L(fourth_double_word_16)
mov 24(%edi), %eax
sub 24(%esi), %eax
mov 24(%esi), %ecx
cmp %ecx, 24(%edi)
jne L(nequal)
RETURN
.p2align 4
L(fourth_double_word_16):
mov 28(%edi), %eax
sub 28(%esi), %eax
mov 28(%esi), %ecx
cmp %ecx, 28(%edi)
jne L(nequal)
RETURN
.p2align 4
L(less4_double_words_32):
xor %eax, %eax
test %dl, %dl
jz L(next_two_double_words_32)
and $15, %dl
jz L(second_double_word_32)
mov 32(%edi), %eax
sub 32(%esi), %eax
mov 32(%esi), %ecx
cmp %ecx, 32(%edi)
jne L(nequal)
RETURN
.p2align 4
L(second_double_word_32):
mov 36(%edi), %eax
sub 36(%esi), %eax
mov 36(%esi), %ecx
cmp %ecx, 36(%edi)
jne L(nequal)
RETURN
.p2align 4
L(next_two_double_words_32):
and $15, %dh
jz L(fourth_double_word_32)
mov 40(%edi), %eax
sub 40(%esi), %eax
mov 40(%esi), %ecx
cmp %ecx, 40(%edi)
jne L(nequal)
RETURN
.p2align 4
L(fourth_double_word_32):
mov 44(%edi), %eax
sub 44(%esi), %eax
mov 44(%esi), %ecx
cmp %ecx, 44(%edi)
jne L(nequal)
RETURN
.p2align 4
L(less4_double_words_48):
xor %eax, %eax
test %dl, %dl
jz L(next_two_double_words_48)
and $15, %dl
jz L(second_double_word_48)
mov 48(%edi), %eax
sub 48(%esi), %eax
mov 48(%esi), %ecx
cmp %ecx, 48(%edi)
jne L(nequal)
RETURN
.p2align 4
L(second_double_word_48):
mov 52(%edi), %eax
sub 52(%esi), %eax
mov 52(%esi), %ecx
cmp %ecx, 52(%edi)
jne L(nequal)
RETURN
.p2align 4
L(next_two_double_words_48):
and $15, %dh
jz L(fourth_double_word_48)
mov 56(%edi), %eax
sub 56(%esi), %eax
mov 56(%esi), %ecx
cmp %ecx, 56(%edi)
jne L(nequal)
RETURN
.p2align 4
L(fourth_double_word_48):
mov 60(%edi), %eax
sub 60(%esi), %eax
RETURN
.p2align 4
L(return):
mov 60(%esi), %ecx
cmp %ecx, 60(%edi)
jne L(nequal)
RETURN
.p2align 4
L(nequal):
mov $1, %eax
ja L(nequal_bigger)
jg L(return)
neg %eax
RETURN
L(nequal_bigger):
.p2align 4
L(return):
RETURN
.p2align 4
@ -988,7 +1004,7 @@ L(equal):
.p2align 4
L(neq):
mov $1, %eax
ja L(neq_bigger)
jg L(neq_bigger)
neg %eax
L(neq_bigger):
@ -999,5 +1015,5 @@ L(eq):
xorl %eax, %eax
ret
END (STRCMP)
END (__wcscmp_sse2)
#endif

109
sysdeps/x86_64/wcscmp.S
View File

@ -20,6 +20,8 @@
#include <sysdep.h>
/* Note: wcscmp uses signed comparison, not unsighed as in strcmp function. */
.text
ENTRY (wcscmp)
/*
@ -76,7 +78,7 @@ L(continue_48_48):
jne L(nequal)
test %ecx, %ecx
jz L(equal)
movdqu 16(%rdi), %xmm1
movdqu 16(%rsi), %xmm2
pcmpeqd %xmm1, %xmm0 /* Any null double_word? */
@ -209,21 +211,21 @@ L(continue_00_48):
test %ecx, %ecx
jnz L(less4_double_words1)
sub (%rsi), %eax
jnz L(return)
cmp (%rsi), %eax
jne L(nequal)
mov 4(%rdi), %eax
sub 4(%rsi), %eax
jnz L(return)
cmp 4(%rsi), %eax
jne L(nequal)
mov 8(%rdi), %eax
sub 8(%rsi), %eax
jnz L(return)
cmp 8(%rsi), %eax
jne L(nequal)
mov 12(%rdi), %eax
sub 12(%rsi), %eax
jnz L(return)
cmp 12(%rsi), %eax
jne L(nequal)
movdqu 16(%rsi), %xmm2
pcmpeqd %xmm2, %xmm0 /* Any null double_word? */
pcmpeqd 16(%rdi), %xmm2 /* compare first 4 double_words for equality */
@ -530,21 +532,21 @@ L(continue_48_00):
test %ecx, %ecx
jnz L(less4_double_words1)
sub (%rsi), %eax
jnz L(return)
cmp (%rsi), %eax
jne L(nequal)
mov 4(%rdi), %eax
sub 4(%rsi), %eax
jnz L(return)
cmp 4(%rsi), %eax
jne L(nequal)
mov 8(%rdi), %eax
sub 8(%rsi), %eax
jnz L(return)
cmp 8(%rsi), %eax
jne L(nequal)
mov 12(%rdi), %eax
sub 12(%rsi), %eax
jnz L(return)
cmp 12(%rsi), %eax
jne L(nequal)
movdqu 16(%rdi), %xmm1
pcmpeqd %xmm1, %xmm0 /* Any null double_word? */
pcmpeqd 16(%rsi), %xmm1 /* compare first 4 double_words for equality */
@ -784,25 +786,29 @@ L(less4_double_words1):
test %ecx, %ecx
jz L(equal)
mov 12(%rsi), %edx
mov 12(%rdi), %eax
sub %edx, %eax
mov 12(%rsi), %ecx
cmp %ecx, 12(%rdi)
jne L(nequal)
xor %eax, %eax
ret
.p2align 4
L(less4_double_words):
xor %eax, %eax
test %dl, %dl
jz L(next_two_double_words)
and $15, %dl
jz L(second_double_word)
mov (%rdi), %eax
sub (%rsi), %eax
cmp (%rsi), %eax
jne L(nequal)
ret
.p2align 4
L(second_double_word):
mov 4(%rdi), %eax
sub 4(%rsi), %eax
cmp 4(%rsi), %eax
jne L(nequal)
ret
.p2align 4
@ -810,29 +816,34 @@ L(next_two_double_words):
and $15, %dh
jz L(fourth_double_word)
mov 8(%rdi), %eax
sub 8(%rsi), %eax
cmp 8(%rsi), %eax
jne L(nequal)
ret
.p2align 4
L(fourth_double_word):
mov 12(%rdi), %eax
sub 12(%rsi), %eax
cmp 12(%rsi), %eax
jne L(nequal)
ret
.p2align 4
L(less4_double_words_16):
xor %eax, %eax
test %dl, %dl
jz L(next_two_double_words_16)
and $15, %dl
jz L(second_double_word_16)
mov 16(%rdi), %eax
sub 16(%rsi), %eax
cmp 16(%rsi), %eax
jne L(nequal)
ret
.p2align 4
L(second_double_word_16):
mov 20(%rdi), %eax
sub 20(%rsi), %eax
cmp 20(%rsi), %eax
jne L(nequal)
ret
.p2align 4
@ -840,29 +851,34 @@ L(next_two_double_words_16):
and $15, %dh
jz L(fourth_double_word_16)
mov 24(%rdi), %eax
sub 24(%rsi), %eax
cmp 24(%rsi), %eax
jne L(nequal)
ret
.p2align 4
L(fourth_double_word_16):
mov 28(%rdi), %eax
sub 28(%rsi), %eax
cmp 28(%rsi), %eax
jne L(nequal)
ret
.p2align 4
L(less4_double_words_32):
xor %eax, %eax
test %dl, %dl
jz L(next_two_double_words_32)
and $15, %dl
jz L(second_double_word_32)
mov 32(%rdi), %eax
sub 32(%rsi), %eax
cmp 32(%rsi), %eax
jne L(nequal)
ret
.p2align 4
L(second_double_word_32):
mov 36(%rdi), %eax
sub 36(%rsi), %eax
cmp 36(%rsi), %eax
jne L(nequal)
ret
.p2align 4
@ -870,29 +886,34 @@ L(next_two_double_words_32):
and $15, %dh
jz L(fourth_double_word_32)
mov 40(%rdi), %eax
sub 40(%rsi), %eax
cmp 40(%rsi), %eax
jne L(nequal)
ret
.p2align 4
L(fourth_double_word_32):
mov 44(%rdi), %eax
sub 44(%rsi), %eax
cmp 44(%rsi), %eax
jne L(nequal)
ret
.p2align 4
L(less4_double_words_48):
xor %eax, %eax
test %dl, %dl
jz L(next_two_double_words_48)
and $15, %dl
jz L(second_double_word_48)
mov 48(%rdi), %eax
sub 48(%rsi), %eax
cmp 48(%rsi), %eax
jne L(nequal)
ret
.p2align 4
L(second_double_word_48):
mov 52(%rdi), %eax
sub 52(%rsi), %eax
cmp 52(%rsi), %eax
jne L(nequal)
ret
.p2align 4
@ -900,23 +921,21 @@ L(next_two_double_words_48):
and $15, %dh
jz L(fourth_double_word_48)
mov 56(%rdi), %eax
sub 56(%rsi), %eax
cmp 56(%rsi), %eax
jne L(nequal)
ret
.p2align 4
L(fourth_double_word_48):
mov 60(%rdi), %eax
sub 60(%rsi), %eax
ret
.p2align 4
L(return):
cmp 60(%rsi), %eax
jne L(nequal)
ret
.p2align 4
L(nequal):
mov $1, %eax
ja L(nequal_bigger)
jg L(nequal_bigger)
neg %eax
L(nequal_bigger):

4
wcsmbs/wcscmp.c
View File

@ -37,11 +37,11 @@ WCSCMP (s1, s2)
{
c1 = (wint_t) *s1++;
c2 = (wint_t) *s2++;
if (c1 == L'\0')
if (c2 == L'\0')
return c1 - c2;
}
while (c1 == c2);
return c1 - c2;
return c1 < c2 ? -1 : 1;
}
libc_hidden_def (WCSCMP)