Add optimized x86-64 implementation of strnlen.

While at it, beef up the test suite for strnlen and add performance
tests for it, too.

6 files changed, 302 insertions, 21 deletions

diff --git a/ChangeLog b/ChangeLog
index 4a22a07..36b36fc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2010-07-26  Ulrich Drepper  <drepper@redhat.com>
+
+	* string/test-strnlen.c: New file.
+	* string/Makefile (strop-tests): Add strnlen.
+	* string/tester.c (test_strnlen): Add a few more test cases.
+	* string/tst-strlen.c: Better error reporting.
+
+	* sysdeps/x86_64/strnlen.S: New file.
+
 2010-07-24  Ulrich Drepper  <drepper@redhat.com>
 
 	* sysdeps/x86_64/multiarch/strstr.c (__m128i_strloadu_tolower): Use
diff --git a/string/Makefile b/string/Makefile
index 0267ea1..e8eb514 100644
--- a/string/Makefile
+++ b/string/Makefile
@@ -49,7 +49,7 @@ o-objects.ob	:= memcpy.o memset.o memchr.o
 strop-tests	:= memchr memcmp memcpy memmove mempcpy memset memccpy	\
 		   stpcpy stpncpy strcat strchr strcmp strcpy strcspn	\
 		   strlen strncmp strncpy strpbrk strrchr strspn memmem	\
-		   strstr strcasestr
+		   strstr strcasestr strnlen
 tests		:= tester inl-tester noinl-tester testcopy test-ffs	\
 		   tst-strlen stratcliff tst-svc tst-inlcall		\
 		   bug-strncat1 bug-strspn1 bug-strpbrk1 tst-bswap	\
diff --git a/string/test-strnlen.c b/string/test-strnlen.c
new file mode 100644
index 0000000..cb8c80f
--- /dev/null
+++ b/string/test-strnlen.c
@@ -0,0 +1,197 @@
+/* Test and measure strlen functions.
+   Copyright (C) 1999, 2002, 2003, 2005, 2010 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Written by Jakub Jelinek <jakub@redhat.com>, 1999.
+
+   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.  */
+
+#define TEST_MAIN
+#include "test-string.h"
+
+typedef size_t (*proto_t) (const char *, size_t);
+size_t simple_strnlen (const char *, size_t);
+
+IMPL (simple_strnlen, 0)
+IMPL (strnlen, 1)
+
+size_t
+simple_strnlen (const char *s, size_t maxlen)
+{
+  size_t i;
+
+  for (i = 0; i < maxlen && s[i]; ++i);
+  return i;
+}
+
+static void
+do_one_test (impl_t *impl, const char *s, size_t maxlen, size_t exp_len)
+{
+  size_t len = CALL (impl, s, maxlen);
+  if (len != exp_len)
+    {
+      error (0, 0, "Wrong result in function %s %zd %zd", impl->name,
+	     len, exp_len);
+      ret = 1;
+      return;
+    }
+
+  if (HP_TIMING_AVAIL)
+    {
+      hp_timing_t start __attribute ((unused));
+      hp_timing_t stop __attribute ((unused));
+      hp_timing_t best_time = ~ (hp_timing_t) 0;
+      size_t i;
+
+      for (i = 0; i < 32; ++i)
+	{
+	  HP_TIMING_NOW (start);
+	  CALL (impl, s, maxlen);
+	  HP_TIMING_NOW (stop);
+	  HP_TIMING_BEST (best_time, start, stop);
+	}
+
+      printf ("\t%zd", (size_t) best_time);
+    }
+}
+
+static void
+do_test (size_t align, size_t len, size_t maxlen, int max_char)
+{
+  size_t i;
+
+  align &= 7;
+  if (align + len >= page_size)
+    return;
+
+  for (i = 0; i < len; ++i)
+    buf1[align + i] = 1 + 7 * i % max_char;
+  buf1[align + len] = 0;
+
+  if (HP_TIMING_AVAIL)
+    printf ("Length %4zd, alignment %2zd:", len, align);
+
+  FOR_EACH_IMPL (impl, 0)
+    do_one_test (impl, (char *) (buf1 + align), maxlen, MIN (len, maxlen));
+
+  if (HP_TIMING_AVAIL)
+    putchar ('\n');
+}
+
+static void
+do_random_tests (void)
+{
+  size_t i, j, n, align, len;
+  unsigned char *p = buf1 + page_size - 512;
+
+  for (n = 0; n < ITERATIONS; n++)
+    {
+      align = random () & 15;
+      len = random () & 511;
+      if (len + align > 510)
+	len = 511 - align - (random () & 7);
+      j = len + align + 64;
+      if (j > 512)
+	j = 512;
+
+      for (i = 0; i < j; i++)
+	{
+	  if (i == len + align)
+	    p[i] = 0;
+	  else
+	    {
+	      p[i] = random () & 255;
+	      if (i >= align && i < len + align && !p[i])
+		p[i] = (random () & 127) + 1;
+	    }
+	}
+
+      FOR_EACH_IMPL (impl, 1)
+	{
+	  if (len > 0
+	      && CALL (impl, (char *) (p + align), len - 1) != len - 1)
+	    {
+	      error (0, 0, "Iteration %zd (limited) - wrong result in function %s (%zd) %zd != %zd, p %p",
+		     n, impl->name, align,
+		     CALL (impl, (char *) (p + align), len - 1), len - 1, p);
+	      ret = 1;
+	    }
+	  if (CALL (impl, (char *) (p + align), len) != len)
+	    {
+	      error (0, 0, "Iteration %zd (exact) - wrong result in function %s (%zd) %zd != %zd, p %p",
+		     n, impl->name, align,
+		     CALL (impl, (char *) (p + align), len), len, p);
+	      ret = 1;
+	    }
+	  if (CALL (impl, (char *) (p + align), len + 1) != len)
+	    {
+	      error (0, 0, "Iteration %zd (long) - wrong result in function %s (%zd) %zd != %zd, p %p",
+		     n, impl->name, align,
+		     CALL (impl, (char *) (p + align), len + 1), len, p);
+	      ret = 1;
+	    }
+	}
+    }
+}
+
+int
+test_main (void)
+{
+  size_t i;
+
+  test_init ();
+
+  printf ("%20s", "");
+  FOR_EACH_IMPL (impl, 0)
+    printf ("\t%s", impl->name);
+  putchar ('\n');
+
+  for (i = 1; i < 8; ++i)
+    {
+      do_test (0, i, i - 1, 127);
+      do_test (0, i, i, 127);
+      do_test (0, i, i + 1, 127);
+    }
+
+  for (i = 1; i < 8; ++i)
+    {
+      do_test (i, i, i - 1, 127);
+      do_test (i, i, i, 127);
+      do_test (i, i, i + 1, 127);
+    }
+
+  for (i = 2; i <= 10; ++i)
+    {
+      do_test (0, 1 << i, 5000, 127);
+      do_test (1, 1 << i, 5000, 127);
+    }
+
+  for (i = 1; i < 8; ++i)
+    do_test (0, i, 5000, 255);
+
+  for (i = 1; i < 8; ++i)
+    do_test (i, i, 5000, 255);
+
+  for (i = 2; i <= 10; ++i)
+    {
+      do_test (0, 1 << i, 5000, 255);
+      do_test (1, 1 << i, 5000, 255);
+    }
+
+  do_random_tests ();
+  return ret;
+}
+
+#include "../test-skeleton.c"
diff --git a/string/tester.c b/string/tester.c
index 773e969..01da046 100644
--- a/string/tester.c
+++ b/string/tester.c
@@ -1,5 +1,5 @@
 /* Tester for string functions.
-   Copyright (C) 1995-2001, 2003, 2005, 2008 Free Software Foundation, Inc.
+   Copyright (C) 1995-2001, 2003, 2005, 2008, 2010 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
@@ -441,20 +441,21 @@ test_strnlen (void)
   check (strnlen ("", 10) == 0, 1);		/* Empty. */
   check (strnlen ("a", 10) == 1, 2);		/* Single char. */
   check (strnlen ("abcd", 10) == 4, 3);		/* Multiple chars. */
-  check (strnlen ("foo", (size_t)-1) == 3, 4);	/* limits of n. */
-
-  {
-    char buf[4096];
-    int i;
-    char *p;
-    for (i=0; i < 0x100; i++)
-      {
-	p = (char *) ((unsigned long int)(buf + 0xff) & ~0xff) + i;
-	strcpy (p, "OK");
-	strcpy (p+3, "BAD/WRONG");
-	check (strnlen (p, 100) == 2, 5+i);
-      }
-   }
+  check (strnlen ("foo", (size_t) -1) == 3, 4);	/* limits of n. */
+  check (strnlen ("abcd", 0) == 0, 5);		/* Restricted. */
+  check (strnlen ("abcd", 1) == 1, 6);		/* Restricted. */
+  check (strnlen ("abcd", 2) == 2, 7);		/* Restricted. */
+  check (strnlen ("abcd", 3) == 3, 8);		/* Restricted. */
+  check (strnlen ("abcd", 4) == 4, 9);		/* Restricted. */
+
+  char buf[4096];
+  for (int i = 0; i < 0x100; ++i)
+    {
+      char *p = (char *) ((unsigned long int)(buf + 0xff) & ~0xff) + i;
+      strcpy (p, "OK");
+      strcpy (p + 3, "BAD/WRONG");
+      check (strnlen (p, 100) == 2, 10 + i);
+    }
 }
 
 static void
@@ -988,7 +989,7 @@ test_memcmp (void)
   int cnt = 1;
   char one[21];
   char two[21];
-  
+
   it = "memcmp";
   check(memcmp("a", "a", 1) == 0, cnt++);	/* Identity. */
   check(memcmp("abc", "abc", 3) == 0, cnt++);	/* Multicharacter. */
diff --git a/string/tst-strlen.c b/string/tst-strlen.c
index a1e1159..8cbe441 100644
--- a/string/tst-strlen.c
+++ b/string/tst-strlen.c
@@ -31,11 +31,21 @@ main(int argc, char *argv[])
 	      buf[words * 4 + 3] = (last & 8) != 0 ? 'e' : '\0';
 	      buf[words * 4 + 4] = '\0';
 
-	      if (strlen (buf) != words * 4 + lens[last]
-		  || strnlen (buf, -1) != words * 4 + lens[last])
+	      if (strlen (buf) != words * 4 + lens[last])
 		{
-		  printf ("failed for base=%Zu, words=%Zu, and last=%Zu\n",
-			  base, words, last);
+		  printf ("\
+strlen failed for base=%Zu, words=%Zu, and last=%Zu (is %zd, expected %zd)\n",
+			  base, words, last,
+			  strlen (buf), words * 4 + lens[last]);
+		  return 1;
+		}
+
+	      if (strnlen (buf, -1) != words * 4 + lens[last])
+		{
+		  printf ("\
+strnlen failed for base=%Zu, words=%Zu, and last=%Zu (is %zd, expected %zd)\n",
+			  base, words, last,
+			  strnlen (buf, -1), words * 4 + lens[last]);
 		  return 1;
 		}
 	    }
diff --git a/sysdeps/x86_64/strnlen.S b/sysdeps/x86_64/strnlen.S
new file mode 100644
index 0000000..939782d
--- /dev/null
+++ b/sysdeps/x86_64/strnlen.S
@@ -0,0 +1,64 @@
+/* strnlen(str,maxlen) -- determine the length of the string STR up to MAXLEN.
+   Copyright (C) 2010 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <sysdep.h>
+
+
+	.text
+ENTRY(__strnlen)
+	movq	%rsi, %rax
+	testq	%rsi, %rsi
+	jz	3f
+	pxor	%xmm2, %xmm2
+	movq	%rdi, %rcx
+	movq	%rdi, %r8
+	movq	$16, %r9
+	andq	$~15, %rdi
+	movdqa	%xmm2, %xmm1
+	pcmpeqb	(%rdi), %xmm2
+	orl	$0xffffffff, %r10d
+	subq	%rdi, %rcx
+	shll	%cl, %r10d
+	subq	%rcx, %r9
+	pmovmskb %xmm2, %edx
+	andl	%r10d, %edx
+	jnz	1f
+	subq	%r9, %rsi
+	jbe	3f
+
+2:	movdqa	16(%rdi), %xmm0
+	leaq	16(%rdi), %rdi
+	pcmpeqb	%xmm1, %xmm0
+	pmovmskb %xmm0, %edx
+	testl	%edx, %edx
+	jnz	1f
+	subq	$16, %rsi
+	jnbe	2b
+3:	ret
+
+1:	subq	%r8, %rdi
+	bsfl	%edx, %edx
+	addq	%rdi, %rdx
+	cmpq	%rdx, %rax
+	cmovnbq	%rdx, %rax
+	ret
+END(__strnlen)
+weak_alias (__strnlen, strnlen)
+libc_hidden_def (strnlen)