--- old/src/hotspot/share/gc/parallel/psParallelCompact.hpp	2018-05-02 11:09:01.264103077 +0200
+++ new/src/hotspot/share/gc/parallel/psParallelCompact.hpp	2018-05-02 11:09:00.979094334 +0200
@@ -968,6 +968,7 @@
   static SpaceInfo            _space_info[last_space_id];
 
   // Reference processing (used in ...follow_contents)
+  static SpanSubjectToDiscoveryClosure  _span_based_discoverer;
   static ReferenceProcessor*  _ref_processor;
 
   // Values computed at initialization and used by dead_wood_limiter().