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-rw-r--r--sysdeps/x86_64/multiarch/strstr.c388
1 files changed, 25 insertions, 363 deletions
diff --git a/sysdeps/x86_64/multiarch/strstr.c b/sysdeps/x86_64/multiarch/strstr.c
index cd63b68c01..fbff3a8ec0 100644
--- a/sysdeps/x86_64/multiarch/strstr.c
+++ b/sysdeps/x86_64/multiarch/strstr.c
@@ -1,6 +1,6 @@
-/* strstr with SSE4.2 intrinsics
- Copyright (C) 2009-2013 Free Software Foundation, Inc.
- Contributed by Intel Corporation.
+/* Multiple versions of strstr.
+ All versions must be listed in ifunc-impl-list.c.
+ Copyright (C) 2012-2013 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
@@ -17,369 +17,31 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
-#include <nmmintrin.h>
-#include "varshift.h"
-
-#ifndef STRSTR_SSE42
-# define STRSTR_SSE42 __strstr_sse42
-#endif
-
-#ifdef USE_AS_STRCASESTR
-# include <ctype.h>
-# include <locale/localeinfo.h>
-
-# define LOADBYTE(C) tolower (C)
-# define CMPBYTE(C1, C2) (tolower (C1) == tolower (C2))
-#else
-# define LOADBYTE(C) (C)
-# define CMPBYTE(C1, C2) ((C1) == (C2))
-#endif
-
-/* We use 0xe ordered-compare:
- _SIDD_SBYTE_OPS
- | _SIDD_CMP_EQUAL_ORDER
- | _SIDD_LEAST_SIGNIFICANT
- on pcmpistri to do the scanning and string comparsion requirements of
- sub-string match. In the scanning phase, we process Cflag and ECX
- index to locate the first fragment match; once the first fragment
- match position has been identified, we do comparison of subsequent
- string fragments until we can conclude false or true match; whe
- n concluding a false match, we may need to repeat scanning process
- from next relevant offset in the target string.
-
- In the scanning phase we have 4 cases:
- case ECX CFlag ZFlag SFlag
- 1 16 0 0 0
- 2a 16 0 0 1
- 2b 16 0 1 0
- 2c 16 0 1 1
-
- 1. No ordered-comparison match, both 16B fragments are valid, so
- continue to next fragment.
- 2. No ordered-comparison match, there is EOS in either fragment,
- 2a. Zflg = 0, Sflg = 1, we continue
- 2b. Zflg = 1, Sflg = 0, we conclude no match and return.
- 2c. Zflg = 1, sflg = 1, lenth determine match or no match
-
- In the string comparison phase, the 1st fragment match is fixed up
- to produce ECX = 0. Subsequent fragment compare of nonzero index
- and no match conclude a false match.
-
- case ECX CFlag ZFlag SFlag
- 3 X 1 0 0/1
- 4a 0 1 0 0
- 4b 0 1 0 1
- 4c 0 < X 1 0 0/1
- 5 16 0 1 0
-
- 3. An initial ordered-comparison fragment match, we fix up to do
- subsequent string comparison
- 4a. Continuation of fragment comparison of a string compare.
- 4b. EOS reached in the reference string, we conclude true match and
- return
- 4c. String compare failed if index is nonzero, we need to go back to
- scanning
- 5. failed string compare, go back to scanning
- */
-
-#if !(defined USE_AS_STRCASESTR && defined STRCASESTR_NONASCII)
-/* Simple replacement of movdqu to address 4KB boundary cross issue.
- If EOS occurs within less than 16B before 4KB boundary, we don't
- cross to next page. */
-static __m128i
-__m128i_strloadu (const unsigned char * p, __m128i zero)
-{
- if (__builtin_expect ((int) ((size_t) p & 0xfff) > 0xff0, 0))
- {
- size_t offset = ((size_t) p & (16 - 1));
- __m128i a = _mm_load_si128 ((__m128i *) (p - offset));
- int bmsk = _mm_movemask_epi8 (_mm_cmpeq_epi8 (a, zero));
- if ((bmsk >> offset) != 0)
- return __m128i_shift_right (a, offset);
- }
- return _mm_loadu_si128 ((__m128i *) p);
-}
-#endif
-
-#if defined USE_AS_STRCASESTR && !defined STRCASESTR_NONASCII
-
-/* Similar to __m128i_strloadu. Convert to lower case for POSIX/C
- locale and other which have single-byte letters only in the ASCII
- range. */
-static __m128i
-__m128i_strloadu_tolower (const unsigned char *p, __m128i zero, __m128i uclow,
- __m128i uchigh, __m128i lcqword)
-{
- __m128i frag = __m128i_strloadu (p, zero);
-
- /* Compare if 'Z' > bytes. Inverted way to get a mask for byte <= 'Z'. */
- __m128i r2 = _mm_cmpgt_epi8 (uchigh, frag);
- /* Compare if bytes are > 'A' - 1. */
- __m128i r1 = _mm_cmpgt_epi8 (frag, uclow);
- /* Mask byte == ff if byte(r2) <= 'Z' and byte(r1) > 'A' - 1. */
- __m128i mask = _mm_and_si128 (r2, r1);
- /* Apply lowercase bit 6 mask for above mask bytes == ff. */
- return _mm_or_si128 (frag, _mm_and_si128 (mask, lcqword));
-}
-
-#endif
-
-/* Calculate Knuth-Morris-Pratt string searching algorithm (or KMP
- algorithm) overlap for a fully populated 16B vector.
- Input parameter: 1st 16Byte loaded from the reference string of a
- strstr function.
- We don't use KMP algorithm if reference string is less than 16B. */
-static int
-__inline__ __attribute__ ((__always_inline__,))
-KMP16Bovrlap (__m128i s2)
-{
- __m128i b = _mm_unpacklo_epi8 (s2, s2);
- __m128i a = _mm_unpacklo_epi8 (b, b);
- a = _mm_shuffle_epi32 (a, 0);
- b = _mm_srli_si128 (s2, sizeof (char));
- int bmsk = _mm_movemask_epi8 (_mm_cmpeq_epi8 (b, a));
-
- /* _BitScanForward(&k1, bmsk); */
- int k1;
- __asm ("bsfl %[bmsk], %[k1]" : [k1] "=r" (k1) : [bmsk] "r" (bmsk));
- if (!bmsk)
- return 16;
- else if (bmsk == 0x7fff)
- return 1;
- else if (!k1)
- {
- /* There are al least two distinct chars in s2. If byte 0 and 1 are
- idential and the distinct value lies farther down, we can deduce
- the next byte offset to restart full compare is least no earlier
- than byte 3. */
- return 3;
- }
- else
- {
- /* Byte 1 is not degenerated to byte 0. */
- return k1 + 1;
- }
-}
-
-char *
-__attribute__ ((section (".text.sse4.2")))
-STRSTR_SSE42 (const unsigned char *s1, const unsigned char *s2)
-{
-#define p1 s1
- const unsigned char *p2 = s2;
-
-#ifndef STRCASESTR_NONASCII
- if (__builtin_expect (p2[0] == '\0', 0))
- return (char *) p1;
-
- if (__builtin_expect (p1[0] == '\0', 0))
- return NULL;
-
- /* Check if p1 length is 1 byte long. */
- if (__builtin_expect (p1[1] == '\0', 0))
- return p2[1] == '\0' && CMPBYTE (p1[0], p2[0]) ? (char *) p1 : NULL;
-#endif
-
-#ifdef USE_AS_STRCASESTR
-# ifndef STRCASESTR_NONASCII
- if (__builtin_expect (_NL_CURRENT_WORD (LC_CTYPE, _NL_CTYPE_NONASCII_CASE)
- != 0, 0))
- return __strcasestr_sse42_nonascii (s1, s2);
-
- const __m128i uclow = _mm_set1_epi8 (0x40);
- const __m128i uchigh = _mm_set1_epi8 (0x5b);
- const __m128i lcqword = _mm_set1_epi8 (0x20);
- const __m128i zero = _mm_setzero_si128 ();
-# define strloadu(p) __m128i_strloadu_tolower (p, zero, uclow, uchigh, lcqword)
-# else
-# define strloadu __m128i_strloadu_tolower
-# define zero _mm_setzero_si128 ()
-# endif
-#else
-# define strloadu(p) __m128i_strloadu (p, zero)
- const __m128i zero = _mm_setzero_si128 ();
+/* Redefine strstr so that the compiler won't complain about the type
+ mismatch with the IFUNC selector in strong_alias, below. */
+#undef strstr
+#define strstr __redirect_strstr
+#include <string.h>
+#undef strstr
+
+#define STRSTR __strstr_sse2
+#ifdef SHARED
+# undef libc_hidden_builtin_def
+# define libc_hidden_builtin_def(name) \
+ __hidden_ver1 (__strstr_sse2, __GI_strstr, __strstr_sse2);
#endif
- /* p1 > 1 byte long. Load up to 16 bytes of fragment. */
- __m128i frag1 = strloadu (p1);
-
- __m128i frag2;
- if (p2[1] != '\0')
- /* p2 is > 1 byte long. */
- frag2 = strloadu (p2);
- else
- frag2 = _mm_insert_epi8 (zero, LOADBYTE (p2[0]), 0);
-
- /* Unsigned bytes, equal order, does frag2 has null? */
- int cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
- int cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
- int cmp = _mm_cmpistri (frag2, frag1, 0x0c);
- int cmp_s = _mm_cmpistrs (frag2, frag1, 0x0c);
- if (cmp_s & cmp_c)
- {
- int bmsk = _mm_movemask_epi8 (_mm_cmpeq_epi8 (frag2, zero));
- int len;
- __asm ("bsfl %[bmsk], %[len]"
- : [len] "=r" (len) : [bmsk] "r" (bmsk));
- p1 += cmp;
- if ((len + cmp) <= 16)
- return (char *) p1;
-
- /* Load up to 16 bytes of fragment. */
- frag1 = strloadu (p1);
- cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
- cmp_s = _mm_cmpistrs (frag2, frag1, 0x0c);
- cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
- cmp = _mm_cmpistri (frag2, frag1, 0x0c);
- if ((len + cmp) <= 16)
- return (char *) p1 + cmp;
- }
-
- if (cmp_s)
- {
- /* Adjust addr for 16B alginment in ensuing loop. */
- while (!cmp_z)
- {
- p1 += cmp;
- /* Load up to 16 bytes of fragment. */
- frag1 = strloadu (p1);
- cmp = _mm_cmpistri (frag2, frag1, 0x0c);
- cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
- cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
- /* Because s2 < 16 bytes and we adjusted p1 by non-zero cmp
- once already, this time cmp will be zero and we can exit. */
- if ((!cmp) & cmp_c)
- break;
- }
-
- if (!cmp_c)
- return NULL;
-
- /* Since s2 is less than 16 bytes, com_c is definitive
- determination of full match. */
- return (char *) p1 + cmp;
- }
-
- /* General case, s2 is at least 16 bytes or more.
- First, the common case of false-match at first byte of p2. */
- const unsigned char *pt = NULL;
- int kmp_fwd = 0;
-re_trace:
- while (!cmp_c)
- {
- /* frag1 has null. */
- if (cmp_z)
- return NULL;
-
- /* frag 1 has no null, advance 16 bytes. */
- p1 += 16;
- /* Load up to 16 bytes of fragment. */
- frag1 = strloadu (p1);
- /* Unsigned bytes, equal order, is there a partial match? */
- cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
- cmp = _mm_cmpistri (frag2, frag1, 0x0c);
- cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
- }
-
- /* Next, handle initial positive match as first byte of p2. We have
- a partial fragment match, make full determination until we reached
- end of s2. */
- if (!cmp)
- {
- if (cmp_z)
- return (char *) p1;
-
- pt = p1;
- p1 += 16;
- p2 += 16;
- /* Load up to 16 bytes of fragment. */
- frag2 = strloadu (p2);
- }
- else
- {
- /* Adjust 16B alignment. */
- p1 += cmp;
- pt = p1;
- }
-
- /* Load up to 16 bytes of fragment. */
- frag1 = strloadu (p1);
-
- /* Unsigned bytes, equal order, does frag2 has null? */
- cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
- cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
- cmp = _mm_cmpistri (frag2, frag1, 0x0c);
- cmp_s = _mm_cmpistrs (frag2, frag1, 0x0c);
- while (!(cmp | cmp_z | cmp_s))
- {
- p1 += 16;
- p2 += 16;
- /* Load up to 16 bytes of fragment. */
- frag2 = strloadu (p2);
- /* Load up to 16 bytes of fragment. */
- frag1 = strloadu (p1);
- /* Unsigned bytes, equal order, does frag2 has null? */
- cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
- cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
- cmp = _mm_cmpistri (frag2, frag1, 0x0c);
- cmp_s = _mm_cmpistrs (frag2, frag1, 0x0c);
- }
-
- /* Full determination yielded a false result, retrace s1 to next
- starting position.
- Zflg 1 0 1 0/1
- Sflg 0 1 1 0/1
- cmp na 0 0 >0
- action done done continue continue if s2 < s1
- false match retrace s1 else false
- */
-
- if (cmp_s & !cmp)
- return (char *) pt;
- if (cmp_z)
- {
- if (!cmp_s)
- return NULL;
-
- /* Handle both zero and sign flag set and s1 is shorter in
- length. */
- int bmsk = _mm_movemask_epi8 (_mm_cmpeq_epi8 (zero, frag2));
- int bmsk1 = _mm_movemask_epi8 (_mm_cmpeq_epi8 (zero, frag1));
- int len;
- int len1;
- __asm ("bsfl %[bmsk], %[len]"
- : [len] "=r" (len) : [bmsk] "r" (bmsk));
- __asm ("bsfl %[bmsk1], %[len1]"
- : [len1] "=r" (len1) : [bmsk1] "r" (bmsk1));
- if (len >= len1)
- return NULL;
- }
- else if (!cmp)
- return (char *) pt;
-
- /* Otherwise, we have to retrace and continue. Default of multiple
- paths that need to retrace from next byte in s1. */
- p2 = s2;
- frag2 = strloadu (p2);
-
- if (!kmp_fwd)
- kmp_fwd = KMP16Bovrlap (frag2);
+#include "string/strstr.c"
- /* KMP algorithm predicted overlap needs to be corrected for
- partial fragment compare. */
- p1 = pt + (kmp_fwd > cmp ? cmp : kmp_fwd);
+extern __typeof (__redirect_strstr) __strstr_sse2_unaligned attribute_hidden;
+extern __typeof (__redirect_strstr) __strstr_sse2 attribute_hidden;
- /* Since s2 is at least 16 bytes long, we're certain there is no
- match. */
- if (p1[0] == '\0')
- return NULL;
+#include "init-arch.h"
- /* Load up to 16 bytes of fragment. */
- frag1 = strloadu (p1);
+/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
+ ifunc symbol properly. */
+extern __typeof (__redirect_strstr) __libc_strstr;
+libc_ifunc (__libc_strstr, HAS_FAST_UNALIGNED_LOAD ? __strstr_sse2_unaligned : __strstr_sse2)
- /* Unsigned bytes, equal order, is there a partial match? */
- cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
- cmp = _mm_cmpistri (frag2, frag1, 0x0c);
- cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
- goto re_trace;
-}
+#undef strstr
+strong_alias (__libc_strstr, strstr)
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-25 16:45:29 +0000