--- old/src/hotspot/share/gc/g1/heapRegionSet.hpp	2019-11-26 16:18:16.598873827 +0100
+++ new/src/hotspot/share/gc/g1/heapRegionSet.hpp	2019-11-26 16:18:16.206871883 +0100
@@ -180,6 +180,10 @@
   inline void increase_length(uint node_index);
   inline void decrease_length(uint node_index);
 
+  // Common checks for adding a list.
+  void add_list_common_start(FreeRegionList* from_list);
+  void add_list_common_end(FreeRegionList* from_list);
+
 protected:
   // See the comment for HeapRegionSetBase::clear()
   virtual void clear();
@@ -202,6 +206,8 @@
   // Assumes that the list is ordered and will preserve that order. The order
   // is determined by hrm_index.
   inline void add_ordered(HeapRegion* hr);
+  // Same restrictions as above, but adds the region last in the list.
+  inline void add_to_tail(HeapRegion* region_to_add);
 
   // Removes from head or tail based on the given argument.
   HeapRegion* remove_region(bool from_head);
@@ -212,10 +218,15 @@
   // Merge two ordered lists. The result is also ordered. The order is
   // determined by hrm_index.
   void add_ordered(FreeRegionList* from_list);
+  void append_ordered(FreeRegionList* from_list);
 
   // It empties the list by removing all regions from it.
   void remove_all();
 
+  // Abandon current free list. Requires that all regions in the current list
+  // are taken care of separately, to allow a rebuild.
+  void abandon();
+
   // Remove all (contiguous) regions from first to first + num_regions -1 from
   // this list.
   // Num_regions must be > 1.