--- a/hotspot/src/share/vm/ci/ciInstanceKlass.cpp	Fri Oct 08 02:42:17 2010 -0700
+++ b/hotspot/src/share/vm/ci/ciInstanceKlass.cpp	Mon Oct 11 04:18:58 2010 -0700
@@ -471,7 +471,7 @@
     ciField* field = fields->at(i);
     int offset = field->offset_in_bytes();
     int size   = (field->_type == NULL) ? heapOopSize : field->size_in_bytes();
-    assert(last_offset <= offset, "no field overlap");
+    assert(last_offset <= offset, err_msg("no field overlap: %d <= %d", last_offset, offset));
     if (last_offset > (int)sizeof(oopDesc))
       assert((offset - last_offset) < BytesPerLong, "no big holes");
     // Note:  Two consecutive T_BYTE fields will be separated by wordSize-1