Use memrchr() when available

On x86_64 glibc memrchr() uses SSE/AVX CPU extensions and works much
faster then naive loop. On x86 32-bit we still use inlined version.

memrchr() is a GNU extension. Its prototype  becomes available when
<string.h> is included with defined _GNU_SOURCE macro. Previously, we
defined it in "php_config.h", but some sources may include <string.h>
befire it. To avod mess we also pass -D_GNU_SOURCE to C compiler.

Zend/zend_operators.h

@@ -211,6 +211,10 @@ zend_memnstr(const char *haystack, const char *needle, size_t needle_len, const
 
 static zend_always_inline const void *zend_memrchr(const void *s, int c, size_t n)
 {
+#if defined(HAVE_MEMRCHR) && !defined(i386)
+	/* On x86 memrchr() doesn't use SSE/AVX, so inlined version is faster */
+	return (const void*)memrchr(s, c, n);
+#else
 	const unsigned char *e;
 	if (0 == n) {
 		return NULL;
@@ -222,6 +226,7 @@ static zend_always_inline const void *zend_memrchr(const void *s, int c, size_t
 		}
 	}
 	return NULL;
+#endif
 }
 
 

Zend/zend_signal.c

@@ -25,7 +25,9 @@
    All other licensing and usage conditions are those of the PHP Group.
 */
 
-#define _GNU_SOURCE
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
 #include <string.h>
 
 #include "zend.h"

configure.ac

@@ -265,6 +265,12 @@ else
   AC_MSG_RESULT(no)
 fi
 
+dnl The effect of _GNU_SOURCE defined in config.h depeds on includes order
+if test "$ac_cv_safe_to_define___extensions__" = yes ; then
+  AC_MSG_CHECKING(whether to use -D_GNU_SOURCE cflag)
+  CPPFLAGS="$CPPFLAGS -D_GNU_SOURCE"
+  AC_MSG_RESULT(yes)
+fi
 
 dnl Include Zend configurations.
 dnl ----------------------------------------------------------------------------
@@ -609,6 +615,7 @@ vasprintf \
 asprintf \
 nanosleep \
 memmem \
+memrchr \
 )
 
 AX_FUNC_WHICH_GETHOSTBYNAME_R

ext/pdo_firebird/firebird_driver.c

@@ -18,7 +18,9 @@
 #include "config.h"
 #endif
 
-#define _GNU_SOURCE
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
 
 #include "php.h"
 #include "zend_exceptions.h"

ext/zlib/zlib_fopen_wrapper.c

@@ -15,7 +15,9 @@
    +----------------------------------------------------------------------+
  */
 
-#define _GNU_SOURCE
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
 
 #include "php.h"
 #include "php_zlib.h"

main/snprintf.c

@@ -14,7 +14,9 @@
   +----------------------------------------------------------------------+
 */
 
-#define _GNU_SOURCE
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
 #include "php.h"
 
 #include <zend_strtod.h>

main/spprintf.c

@@ -72,7 +72,9 @@
  * SIO stdio-replacement strx_* functions by Panos Tsirigotis
  * <panos@alumni.cs.colorado.edu> for xinetd.
  */
-#define _GNU_SOURCE
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
 #include "php.h"
 
 #include <stddef.h>

main/streams/cast.c

@@ -14,7 +14,9 @@
    +----------------------------------------------------------------------+
  */
 
-#define _GNU_SOURCE
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
 #include "php.h"
 #include "php_globals.h"
 #include "php_network.h"

main/streams/memory.c

@@ -14,7 +14,9 @@
    +----------------------------------------------------------------------+
  */
 
-#define _GNU_SOURCE
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
 #include "php.h"
 #include "ext/standard/base64.h"
 

main/streams/streams.c

@@ -17,7 +17,9 @@
    +----------------------------------------------------------------------+
  */
 
-#define _GNU_SOURCE
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
 #include "php.h"
 #include "php_globals.h"
 #include "php_memory_streams.h"

sapi/fpm/fpm/fpm_trace_pread.c

@@ -1,6 +1,8 @@
 	/* (c) 2007,2008 Andrei Nigmatulin */
 
-#define _GNU_SOURCE
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
 #define _FILE_OFFSET_BITS 64
 
 #include "fpm_config.h"