Mailing List Archive

* common/mischelp.h (wipememory2): Replace macro with function
prototype.
* common/mischelp.c (wipememory2): New.
--

In new wipememory2 function, memset is called through volatile
function pointer to so that compiler won't optimize away the call.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
---
common/mischelp.c | 10 ++++++++++
common/mischelp.h | 12 ++++--------
2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/common/mischelp.c b/common/mischelp.c
index 75ba60714..008aaab55 100644
--- a/common/mischelp.c
+++ b/common/mischelp.c
@@ -49,6 +49,16 @@
#include "mischelp.h"


+void
+wipememory2 (void *ptr, int set, size_t len)
+{
+ /* Prevent compiler from optimizing away the call to memset by accessing
+ memset through volatile pointer. */
+ static void *(*volatile memset_ptr)(void *, int, size_t) = (void *)memset;
+ memset_ptr (ptr, set, len);
+}
+
+
/* Check whether the files NAME1 and NAME2 are identical. This is for
example achieved by comparing the inode numbers of the files. */
int
diff --git a/common/mischelp.h b/common/mischelp.h
index 18ec96edf..2554c2160 100644
--- a/common/mischelp.h
+++ b/common/mischelp.h
@@ -47,14 +47,10 @@ time_t timegm (struct tm *tm);
#define DIM(v) (sizeof(v)/sizeof((v)[0]))
#define DIMof(type,member) DIM(((type *)0)->member)

-/* To avoid that a compiler optimizes certain memset calls away, these
- macros may be used instead. */
-#define wipememory2(_ptr,_set,_len) do { \
- volatile char *_vptr=(volatile char *)(_ptr); \
- size_t _vlen=(_len); \
- while(_vlen) { *_vptr=(_set); _vptr++; _vlen--; } \
- } while(0)
-#define wipememory(_ptr,_len) wipememory2(_ptr,0,_len)
+/* To avoid that a compiler optimizes certain memset calls away,
+ wipememory function and macro may be used instead. */
+void wipememory2(void *ptr, int set, size_t len);
+#define wipememory(_ptr,_len) wipememory2((_ptr),0,(_len))


/* Include hacks which are mainly required for Slowaris. */


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