Re: [PATCH] Use strlen when searching for a nul char

[Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>]

ping

________________________________________
From: Wilco Dijkstra
Sent: 20 April 2016 15:50
To: Mike Frysinger
Cc: 'GNU C Library'; nd
Subject: Re: [PATCH] Use strlen when searching for a nul char

Mike Frysinger wrote:
> the issue isn't what version of gcc is used to build glibc.  this is an
> installed header, and we made guarantees that the installed headers work
> with much older versions of gcc at runtime.  those guarantees don't hard
> extend to pure-optimizations, but typically we wait much longer for those
> versions to cycle out of common use.  dropping code that requires gcc7
> (which doesn't even exist yet) doesn't fall into that bucket.

OK, here is the patch with the old define left in:

diff --git a/string/bits/string2.h b/string/bits/string2.h
index 80987602f34ded483854bcea86dabd5b81e42a18..62edc93b0f04249a504078caeee8fca192e91df8 100644
--- a/string/bits/string2.h
+++ b/string/bits/string2.h
@@ -60,13 +60,25 @@

 #ifndef _HAVE_STRING_ARCH_strchr
 extern void *__rawmemchr (const void *__s, int __c);
-#  define strchr(s, c) \
+# define strchr(s, c) \
   (__extension__ (__builtin_constant_p (c) && !__builtin_constant_p (s)              \
                  && (c) == '\0'                                              \
                  ? (char *) __rawmemchr (s, c)                               \
                  : __builtin_strchr (s, c)))
 #endif

+#ifndef _HAVE_STRING_ARCH_rawmemchr
+extern void *__rawmemchr (const void *__s, int __c);
+# define __rawmemchr(s, c) \
+    (__extension__ ({ char *__s = (char *)(s);         \
+      __builtin_constant_p (c) && (c) == '\0'          \
+      ? (void *)(__s + strlen (__s))                   \
+      : __rawmemchr (__s, (c));}))
+# ifdef __USE_GNU
+#  define rawmemchr(s,c) __rawmemchr ((s), (c))
+# endif
+#endif
+

 /* Copy SRC to DEST, returning pointer to final NUL byte.  */
 #ifdef __USE_GNU