--- old/src/hotspot/share/gc/shared/generation.hpp	2018-05-02 11:09:07.103282191 +0200
+++ new/src/hotspot/share/gc/shared/generation.hpp	2018-05-02 11:09:06.812273264 +0200
@@ -100,6 +100,7 @@
   VirtualSpace _virtual_space;
 
   // ("Weak") Reference processing support
+  SpanSubjectToDiscoveryClosure _span_based_discoverer;
   ReferenceProcessor* _ref_processor;
 
   // Performance Counters