Added support for OpenMP barriers -- if libgomp.so has been built with debug information. More in general, added support for nested synchronization constructs.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@7642 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/exp-drd/drd_error.c b/exp-drd/drd_error.c
index fdf9b0e..cc1923b 100644
--- a/exp-drd/drd_error.c
+++ b/exp-drd/drd_error.c
@@ -249,8 +249,9 @@
    else if (ai.akind == eMallocd && ai.lastchange)
    {
       VG_(message)(Vg_UserMsg,
-                   "Address 0x%08lx is at offset %ld. Allocation context:",
-                   dri->addr, ai.rwoffset);
+                   "Address 0x%lx is at offset %ld from 0x%lx."
+                   " Allocation context:",
+                   dri->addr, ai.rwoffset, dri->addr - ai.rwoffset);
       VG_(pp_ExeContext)(ai.lastchange);
    }
    else