Followup to r5991: when leak checking, treat zero-sized blocks as if

they had size one.  Otherwise they appear to cover no address space,
so no pointers to them are ever found, and so they are always
incorrectly marked as leaked.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@5994

diff --git a/memcheck/mc_leakcheck.c b/memcheck/mc_leakcheck.c
index 921ee919debfcdd3c193b539d1618e12c0a9d53f..f194500720663f6ecae5be5bc8414e775460a83a 100644 (file)
--- a/memcheck/mc_leakcheck.c
+++ b/memcheck/mc_leakcheck.c
@@ -201,6 +201,14 @@ Int find_shadow_for ( Addr       ptr,
       mid      = (lo + hi) / 2;
       a_mid_lo = shadows[mid]->data;
       a_mid_hi = shadows[mid]->data + shadows[mid]->size;
+      /* Extent of block 'mid' is [a_mid_lo .. a_mid_hi).
+         Special-case zero-sized blocks - treat them as if they had
+         size 1.  Not doing so causes them to not cover any address
+         range at all and so will never be identified as the target of
+         any pointer, which causes them to be incorrectly reported as
+         definitely leaked. */
+      if (shadows[mid]->size == 0)
+         a_mid_hi++;
 
       if (ptr < a_mid_lo) {
          hi = mid-1;
@@ -346,7 +354,9 @@ static void lc_markstack_push_WRK(Addr ptr, Int clique)
 
    tl_assert(sh_no >= 0 && sh_no < lc_n_shadows);
    tl_assert(ptr >= lc_shadows[sh_no]->data);
-   tl_assert(ptr < lc_shadows[sh_no]->data + lc_shadows[sh_no]->size);
+   tl_assert(ptr < lc_shadows[sh_no]->data 
+                   + lc_shadows[sh_no]->size
+                   + (lc_shadows[sh_no]->size==0  ? 1  : 0));
 
    if (lc_markstack[sh_no].state == Unreached) {
       if (0)