src/hotspot/share/gc/parallel/psOldGen.cpp

@@ -393,11 +393,13 @@
   public:
    VerifyObjectStartArrayClosure(ObjectStartArray* start_array) :
      _start_array(start_array) { }
  
    virtual void do_object(oop obj) {
-     HeapWord* test_addr = cast_from_oop<HeapWord*>(obj) + 1;
+     // With compact headers, the objects can be one-word sized.
+     size_t int_off = UseCompactObjectHeaders ? MIN2((size_t)1, obj->size() - 1) : 1;
+     HeapWord* test_addr = cast_from_oop<HeapWord*>(obj) + int_off;
      guarantee(_start_array->object_start(test_addr) == cast_from_oop<HeapWord*>(obj), "ObjectStartArray cannot find start of object");
      guarantee(_start_array->is_block_allocated(cast_from_oop<HeapWord*>(obj)), "ObjectStartArray missing block allocation");
    }
  };