1 /*
   2  * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_GC_IMPLEMENTATION_SHARED_LIVERANGE_HPP
  26 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_LIVERANGE_HPP
  27 
  28 #include "memory/memRegion.hpp"
  29 #include "utilities/copy.hpp"
  30 
  31 // This is a shared helper class used during phase 3 and 4 to move all the objects
  32 // Dead regions in a Space are linked together to keep track of the live regions
  33 // so that the live data can be traversed quickly without having to look at each
  34 // object.
  35 
  36 class LiveRange: public MemRegion {
  37 public:
  38   LiveRange(HeapWord* bottom, HeapWord* top): MemRegion(bottom, top) {}
  39 
  40   void set_end(HeapWord* e) {
  41     assert(e >= start(), "should be a non-zero range");
  42     MemRegion::set_end(e);
  43   }
  44   void set_word_size(size_t ws) {
  45     MemRegion::set_word_size(ws);
  46   }
  47 
  48   LiveRange * next() { return (LiveRange *) end(); }
  49 
  50   void move_to(HeapWord* destination) {
  51     Copy::aligned_conjoint_words(start(), destination, word_size());
  52   }
  53 };
  54 
  55 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_LIVERANGE_HPP