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Re: Fix tst-obprintf - and mcheck in general

On 04/26/2012 03:15 PM, Andreas Jaeger wrote:
On Thursday, April 26, 2012 15:01:16 Richard Guenther wrote:
On Thu, 26 Apr 2012, Andreas Schwab wrote:
Andreas Jaeger<> writes:
One option is to compile with -fno-builtin-malloc, the alternative
would be to use some otherways to initialize the malloc

Does it work to use the equivalent of math_opt_barrier from <math_private.h>?

Yes, that it should work, too.

Yes, the following works as well.

What's the best place to put this barrier in? Put it into include/malloc.h?

Which is the better way? A barrier like below or setting -fno-builtin-malloc?



diff --git a/malloc/mcheck.c b/malloc/mcheck.c
index 9213740..7491c49 100644
--- a/malloc/mcheck.c
+++ b/malloc/mcheck.c
@@ -370,6 +370,12 @@ mabort (enum mcheck_status status)

+#ifndef malloc_opt_barrier
+#define malloc_opt_barrier(x) \
+({ __typeof (x) __x = x; __asm ("" : "+m" (__x)); __x; })
  mcheck (func)
       void (*func) (enum mcheck_status);
@@ -381,6 +387,7 @@ mcheck (func)
        /* We call malloc() once here to ensure it is initialized.  */
        void *p = malloc (0);
+      p = malloc_opt_barrier (p);
        free (p);

old_free_hook = __free_hook;

 Andreas Jaeger aj@{,} Twitter/Identica: jaegerandi
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