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Fix rawmemchr build with GCC 8
- From: Joseph Myers <joseph at codesourcery dot com>
- To: <libc-alpha at sourceware dot org>
- Date: Mon, 8 May 2017 14:34:25 +0000
- Subject: Fix rawmemchr build with GCC 8
- Authentication-results: sourceware.org; auth=none
The default rawmemchr implementation uses memchr with size (size_t)-1,
which produces a warning with current GCC mainline. The warning seems
reasonable for normal code, so this patch uses the DIAG_* macros to
disable it.
Tested (compilation of glibc only) with build-many-glibcs.py for
arm-linux-gnueabi and powerpc64le-linux-gnu, two architectures for
which the build was previously failing. Note that the glibc testsuite
will still fail to build with GCC mainline because of
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80669>.
2017-05-08 Joseph Myers <joseph@codesourcery.com>
* string/rawmemchr.c: Include <libc-diag.h>.
(RAWMEMCHR): Disable -Wstringop-overflow around call to memchr
with size (size_t)-1.
diff --git a/string/rawmemchr.c b/string/rawmemchr.c
index 54e8dcd..42a3f8a 100644
--- a/string/rawmemchr.c
+++ b/string/rawmemchr.c
@@ -16,6 +16,7 @@
<http://www.gnu.org/licenses/>. */
#include <string.h>
+#include <libc-diag.h>
#ifndef RAWMEMCHR
# define RAWMEMCHR __rawmemchr
@@ -25,8 +26,15 @@
void *
RAWMEMCHR (const void *s, int c)
{
+ DIAG_PUSH_NEEDS_COMMENT;
+#if __GNUC_PREREQ (7, 0)
+ /* GCC 8 warns about the size passed to memchr being larger than
+ PTRDIFF_MAX; the use of SIZE_MAX is deliberate here. */
+ DIAG_IGNORE_NEEDS_COMMENT (8, "-Wstringop-overflow=");
+#endif
if (c != '\0')
return memchr (s, c, (size_t)-1);
+ DIAG_POP_NEEDS_COMMENT;
return (char *)s + strlen (s);
}
libc_hidden_def (__rawmemchr)
--
Joseph S. Myers
joseph@codesourcery.com