8016556: G1: Use ArrayAllocator for BitMaps

Reviewed-by: tschatzl, dholmes, coleenp, johnc

src/share/vm/memory/allocation.hpp

@@ -713,13 +713,21 @@ public:
 // is set so that we always use malloc except for Solaris where we set the
 // limit to get mapped memory.
 template <class E, MEMFLAGS F>
-class ArrayAllocator : StackObj {
+class ArrayAllocator VALUE_OBJ_CLASS_SPEC {
   char* _addr;
   bool _use_malloc;
   size_t _size;
+  bool _free_in_destructor;
  public:
-  ArrayAllocator() : _addr(NULL), _use_malloc(false), _size(0) { }
-  ~ArrayAllocator() { free(); }
+  ArrayAllocator(bool free_in_destructor = true) :
+    _addr(NULL), _use_malloc(false), _size(0), _free_in_destructor(free_in_destructor) { }
+
+  ~ArrayAllocator() {
+    if (_free_in_destructor) {
+      free();
+    }
+  }
+
   E* allocate(size_t length);
   void free();
 };

src/share/vm/utilities/bitMap.cpp

@@ -41,7 +41,7 @@
 
 
 BitMap::BitMap(bm_word_t* map, idx_t size_in_bits) :
-  _map(map), _size(size_in_bits)
+  _map(map), _size(size_in_bits), _map_allocator(false)
 {
   assert(sizeof(bm_word_t) == BytesPerWord, "Implementation assumption.");
   assert(size_in_bits >= 0, "just checking");
@@ -49,7 +49,7 @@ BitMap::BitMap(bm_word_t* map, idx_t size_in_bits) :
 
 
 BitMap::BitMap(idx_t size_in_bits, bool in_resource_area) :
-  _map(NULL), _size(0)
+  _map(NULL), _size(0), _map_allocator(false)
 {
   assert(sizeof(bm_word_t) == BytesPerWord, "Implementation assumption.");
   resize(size_in_bits, in_resource_area);
@@ -65,8 +65,10 @@ void BitMap::resize(idx_t size_in_bits, bool in_resource_area) {
   if (in_resource_area) {
     _map = NEW_RESOURCE_ARRAY(bm_word_t, new_size_in_words);
   } else {
-    if (old_map != NULL) FREE_C_HEAP_ARRAY(bm_word_t, _map, mtInternal);
-    _map = NEW_C_HEAP_ARRAY(bm_word_t, new_size_in_words, mtInternal);
+    if (old_map != NULL) {
+      _map_allocator.free();
+    }
+    _map = _map_allocator.allocate(new_size_in_words);
   }
   Copy::disjoint_words((HeapWord*)old_map, (HeapWord*) _map,
                        MIN2(old_size_in_words, new_size_in_words));

src/share/vm/utilities/bitMap.hpp

@@ -48,6 +48,7 @@ class BitMap VALUE_OBJ_CLASS_SPEC {
   } RangeSizeHint;
 
  private:
+  ArrayAllocator<bm_word_t, mtInternal> _map_allocator;
   bm_word_t* _map;     // First word in bitmap
   idx_t      _size;    // Size of bitmap (in bits)
 
@@ -113,7 +114,7 @@ class BitMap VALUE_OBJ_CLASS_SPEC {
  public:
 
   // Constructs a bitmap with no map, and size 0.
-  BitMap() : _map(NULL), _size(0) {}
+  BitMap() : _map(NULL), _size(0), _map_allocator(false) {}
 
   // Constructs a bitmap with the given map and size.
   BitMap(bm_word_t* map, idx_t size_in_bits);