--- old/src/hotspot/share/gc/shared/collectedHeap.hpp	2018-10-11 11:58:42.415079312 +0200
+++ new/src/hotspot/share/gc/shared/collectedHeap.hpp	2018-10-11 11:58:42.264080662 +0200
@@ -309,7 +309,7 @@
   }
 
   virtual void fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap);
-  virtual size_t min_dummy_object_size() const;
+  size_t min_dummy_object_size() const;
   size_t tlab_alloc_reserve() const;
 
   // Return the address "addr" aligned by "alignment_in_bytes" if such
@@ -578,7 +578,7 @@
 
   virtual bool is_oop(oop object) const;
 
-  virtual size_t obj_size(oop obj) const;
+  virtual size_t cell_size(size_t obj_size) const { return obj_size; }
 
   // Non product verification and debugging.
 #ifndef PRODUCT