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Re: [PATCH] Use strlen when searching for a nul char
- From: Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>
- To: Mike Frysinger <vapier at gentoo dot org>
- Cc: 'GNU C Library' <libc-alpha at sourceware dot org>, nd <nd at arm dot com>
- Date: Thu, 12 May 2016 14:05:10 +0000
- Subject: Re: [PATCH] Use strlen when searching for a nul char
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________________________________________
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