--- a/src/hotspot/share/oops/oop.inline.hpp	Sun May 20 20:25:51 2018 +0900
+++ b/src/hotspot/share/oops/oop.inline.hpp	Sun May 20 22:08:25 2018 +0200
@@ -266,6 +266,9 @@
 template <class T>
 T*       oopDesc::obj_field_addr_raw(int offset) const { return (T*) field_addr_raw(offset); }
 
+template <typename T>
+size_t   oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
+
 template <DecoratorSet decorators>
 inline oop  oopDesc::obj_field_access(int offset) const             { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
 inline oop  oopDesc::obj_field(int offset) const                    { return HeapAccess<>::oop_load_at(as_oop(), offset);  }