diff -r d70ee55535f4 -r bd4290e6d0a5 hotspot/src/share/vm/gc_implementation/g1/g1BlockOffsetTable.inline.hpp
--- a/hotspot/src/share/vm/gc_implementation/g1/g1BlockOffsetTable.inline.hpp	Tue Nov 27 14:20:21 2012 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1BlockOffsetTable.inline.hpp	Tue Nov 27 14:11:37 2012 -0800
@@ -49,16 +49,17 @@
   char* pc = (char*)p;
   assert(pc >= (char*)_reserved.start() &&
          pc <  (char*)_reserved.end(),
-         "p not in range.");
+         err_msg("p (" PTR_FORMAT ") not in reserved [" PTR_FORMAT ", " PTR_FORMAT ")",
+                 p, (char*)_reserved.start(), (char*)_reserved.end()));
   size_t delta = pointer_delta(pc, _reserved.start(), sizeof(char));
   size_t result = delta >> LogN;
-  assert(result < _vs.committed_size(), "bad index from address");
+  check_index(result, "bad index from address");
   return result;
 }
 
 inline HeapWord*
 G1BlockOffsetSharedArray::address_for_index(size_t index) const {
-  assert(index < _vs.committed_size(), "bad index");
+  check_index(index, "index out of range");
   HeapWord* result = _reserved.start() + (index << LogN_words);
   assert(result >= _reserved.start() && result < _reserved.end(),
          err_msg("bad address from index result " PTR_FORMAT