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authorSiddhesh Poyarekar <siddhesh@redhat.com>2014-11-27 11:15:45 +0530
committerSiddhesh Poyarekar <siddhesh@redhat.com>2014-11-27 11:15:45 +0530
commit1721f0a406e52f976f9daf6f59acf42c1dbd33ff (patch)
treeb298f4a2a303309f541b5a369f74b823708be8a3
parentd88548f497e52ad7633db1f3243daef0ba9fe54b (diff)
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Don't use __warn_memset_zero_len for gcc-5.0 or newer
gcc now warns when the arguments to memset may have been accidentally transposed (i.e. length set to zero instead of the byte), so we don't need that bit of the code in glibc headers anymore. Tested on x86_64. Coe generated by gcc 4.8 is identical with or without the patch. I also tested gcc master, which does not result in any new failures. It does fail quite a few FORTIFY_SOURCE tests, but those failures are not due to this patch.
-rw-r--r--ChangeLog7
-rw-r--r--string/bits/string3.h6
2 files changed, 13 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog
index ab2220d..4acdcc3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2014-11-27 Siddhesh Poyarekar <siddhesh@redhat.com>
+
+ * string/bits/string3.h (__warn_memset_zero_len): Don't
+ declare for gcc newer than 5.0.
+ (memset): Don't test for zero-length __LEN for gcc newer than
+ 5.0.
+
2014-11-27 Joseph Myers <joseph@codesourcery.com>
* stdio-common/tst-fmemopen.c (do_test): Cast st_size values to
diff --git a/string/bits/string3.h b/string/bits/string3.h
index 7606090..801e7ac 100644
--- a/string/bits/string3.h
+++ b/string/bits/string3.h
@@ -19,8 +19,10 @@
# error "Never use <bits/string3.h> directly; include <string.h> instead."
#endif
+#if !__GNUC_PREREQ (5,0)
__warndecl (__warn_memset_zero_len,
"memset used with constant zero length parameter; this could be due to transposed parameters");
+#endif
#ifndef __cplusplus
/* XXX This is temporarily. We should not redefine any of the symbols
@@ -75,12 +77,16 @@ __NTH (mempcpy (void *__restrict __dest, const void *__restrict __src,
__fortify_function void *
__NTH (memset (void *__dest, int __ch, size_t __len))
{
+ /* GCC-5.0 and newer implements these checks in the compiler, so we don't
+ need them here. */
+#if !__GNUC_PREREQ (5,0)
if (__builtin_constant_p (__len) && __len == 0
&& (!__builtin_constant_p (__ch) || __ch != 0))
{
__warn_memset_zero_len ();
return __dest;
}
+#endif
return __builtin___memset_chk (__dest, __ch, __len, __bos0 (__dest));
}