--- old/src/hotspot/share/gc/g1/heapRegionManager.hpp	2018-10-03 10:33:05.399870859 +0200
+++ new/src/hotspot/share/gc/g1/heapRegionManager.hpp	2018-10-03 10:33:04.986858332 +0200
@@ -123,10 +123,10 @@
 public:
   bool is_free(HeapRegion* hr) const;
 #endif
+public:
   // Returns whether the given region is available for allocation.
   bool is_available(uint region) const;
 
- public:
   // Empty constructor, we'll initialize it with the initialize() method.
   HeapRegionManager();
 
@@ -147,6 +147,10 @@
   // is valid.
   inline HeapRegion* at(uint index) const;
 
+  // Return the HeapRegion at the given index, NULL if the index
+  // is for an unavailable region.
+  inline HeapRegion* at_or_null(uint index) const;
+
   // Return the next region (by index) that is part of the same
   // humongous object that hr is part of.
   inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const;