--- old/src/hotspot/cpu/zero/gc/shared/barrierSetAssembler_zero.hpp	2018-10-31 23:12:45.059706642 +0100
+++ new/src/hotspot/cpu/zero/gc/shared/barrierSetAssembler_zero.hpp	2018-10-31 23:12:44.904708082 +0100
@@ -25,6 +25,11 @@
 #ifndef CPU_ZERO_GC_SHARED_BARRIERSETASSEMBLER_ZERO_HPP
 #define CPU_ZERO_GC_SHARED_BARRIERSETASSEMBLER_ZERO_HPP
 
-class BarrierSetAssembler;
+#include "memory/allocation.hpp"
+
+class BarrierSetAssembler : public CHeapObj<mtGC> {
+public:
+  virtual bool needs_explicit_null_check(intptr_t offset) const;
+};
 
 #endif // CPU_ZERO_GC_SHARED_BARRIERSETASSEMBLER_ZERO_HPP