--- old/src/hotspot/share/gc/shared/generation.hpp	2018-05-08 09:41:53.933846293 +0200
+++ new/src/hotspot/share/gc/shared/generation.hpp	2018-05-08 09:41:53.647837456 +0200
@@ -100,6 +100,7 @@
   VirtualSpace _virtual_space;
 
   // ("Weak") Reference processing support
+  SpanSubjectToDiscoveryClosure _span_discoverer;
   ReferenceProcessor* _ref_processor;
 
   // Performance Counters