--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/memory/memRegion.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_MEMORY_MEMREGION_HPP
+#define SHARE_VM_MEMORY_MEMREGION_HPP
+
+#include "memory/allocation.hpp"
+#include "utilities/debug.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+// A very simple data structure representing a contigous region
+// region of address space.
+
+// Note that MemRegions are passed by value, not by reference.
+// The intent is that they remain very small and contain no
+// objects. _ValueObj should never be allocated in heap but we do
+// create MemRegions (in CardTableModRefBS) in heap so operator
+// new and operator new [] added for this special case.
+
+class MetaWord;
+
+class MemRegion VALUE_OBJ_CLASS_SPEC {
+  friend class VMStructs;
+private:
+  HeapWord* _start;
+  size_t    _word_size;
+
+public:
+  MemRegion() : _start(NULL), _word_size(0) {};
+  MemRegion(HeapWord* start, size_t word_size) :
+    _start(start), _word_size(word_size) {};
+  MemRegion(HeapWord* start, HeapWord* end) :
+    _start(start), _word_size(pointer_delta(end, start)) {
+    assert(end >= start, "incorrect constructor arguments");
+  }
+  MemRegion(MetaWord* start, MetaWord* end) :
+    _start((HeapWord*)start), _word_size(pointer_delta(end, start)) {
+    assert(end >= start, "incorrect constructor arguments");
+  }
+
+  MemRegion(const MemRegion& mr): _start(mr._start), _word_size(mr._word_size) {}
+
+  MemRegion intersection(const MemRegion mr2) const;
+  // regions must overlap or be adjacent
+  MemRegion _union(const MemRegion mr2) const;
+  // minus will fail a guarantee if mr2 is interior to this,
+  // since there's no way to return 2 disjoint regions.
+  MemRegion minus(const MemRegion mr2) const;
+
+  HeapWord* start() const { return _start; }
+  HeapWord* end() const   { return _start + _word_size; }
+  HeapWord* last() const  { return _start + _word_size - 1; }
+
+  void set_start(HeapWord* start) { _start = start; }
+  void set_end(HeapWord* end)     { _word_size = pointer_delta(end, _start); }
+  void set_word_size(size_t word_size) {
+    _word_size = word_size;
+  }
+
+  bool contains(const MemRegion mr2) const {
+    return _start <= mr2._start && end() >= mr2.end();
+  }
+  bool contains(const void* addr) const {
+    return addr >= (void*)_start && addr < (void*)end();
+  }
+  bool equals(const MemRegion mr2) const {
+    // first disjunct since we do not have a canonical empty set
+    return ((is_empty() && mr2.is_empty()) ||
+            (start() == mr2.start() && end() == mr2.end()));
+  }
+
+  size_t byte_size() const { return _word_size * sizeof(HeapWord); }
+  size_t word_size() const { return _word_size; }
+
+  bool is_empty() const { return word_size() == 0; }
+  void* operator new(size_t size) throw();
+  void* operator new [](size_t size) throw();
+  void  operator delete(void* p);
+  void  operator delete [](void* p);
+};
+
+// For iteration over MemRegion's.
+
+class MemRegionClosure : public StackObj {
+public:
+  virtual void do_MemRegion(MemRegion mr) = 0;
+};
+
+// A ResourceObj version of MemRegionClosure
+
+class MemRegionClosureRO: public MemRegionClosure {
+public:
+  void* operator new(size_t size, ResourceObj::allocation_type type, MEMFLAGS flags) throw() {
+        return ResourceObj::operator new(size, type, flags);
+  }
+  void* operator new(size_t size, Arena *arena) throw() {
+        return ResourceObj::operator new(size, arena);
+  }
+  void* operator new(size_t size) throw() {
+        return ResourceObj::operator new(size);
+  }
+
+  void  operator delete(void* p) {} // nothing to do
+};
+
+#endif // SHARE_VM_MEMORY_MEMREGION_HPP