1 /*
   2  * Copyright (c) 2013, 2015, 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 package sun.jvm.hotspot.gc.g1;
  26 
  27 import java.util.Iterator;
  28 import java.util.Observable;
  29 import java.util.Observer;
  30 
  31 import sun.jvm.hotspot.debugger.Address;
  32 import sun.jvm.hotspot.runtime.VM;
  33 import sun.jvm.hotspot.runtime.VMObject;
  34 import sun.jvm.hotspot.runtime.VMObjectFactory;
  35 import sun.jvm.hotspot.types.AddressField;
  36 import sun.jvm.hotspot.types.CIntegerField;
  37 import sun.jvm.hotspot.types.Type;
  38 import sun.jvm.hotspot.types.TypeDataBase;
  39 
  40 // Mirror class for G1HeapRegionTable. It's essentially an index -> HeapRegion map.
  41 
  42 public class G1HeapRegionTable extends VMObject {
  43     // HeapRegion** _base;
  44     static private AddressField baseField;
  45     // uint _length;
  46     static private CIntegerField lengthField;
  47     // HeapRegion** _biased_base
  48     static private AddressField biasedBaseField;
  49     // size_t _bias
  50     static private CIntegerField biasField;
  51     // uint _shift_by
  52     static private CIntegerField shiftByField;
  53 
  54     static {
  55         VM.registerVMInitializedObserver(new Observer() {
  56                 public void update(Observable o, Object data) {
  57                     initialize(VM.getVM().getTypeDataBase());
  58                 }
  59             });
  60     }
  61 
  62     static private synchronized void initialize(TypeDataBase db) {
  63         Type type = db.lookupType("G1HeapRegionTable");
  64 
  65         baseField = type.getAddressField("_base");
  66         lengthField = type.getCIntegerField("_length");
  67         biasedBaseField = type.getAddressField("_biased_base");
  68         biasField = type.getCIntegerField("_bias");
  69         shiftByField = type.getCIntegerField("_shift_by");
  70     }
  71 
  72     private HeapRegion at(long index) {
  73         Address arrayAddr = baseField.getValue(addr);
  74         // Offset of &_base[index]
  75         long offset = index * VM.getVM().getAddressSize();
  76         Address regionAddr = arrayAddr.getAddressAt(offset);
  77         return (HeapRegion) VMObjectFactory.newObject(HeapRegion.class,
  78                                                       regionAddr);
  79     }
  80 
  81     public long length() {
  82         return lengthField.getValue(addr);
  83     }
  84 
  85     public long bias() {
  86         return biasField.getValue(addr);
  87     }
  88 
  89     public long shiftBy() {
  90         return shiftByField.getValue(addr);
  91     }
  92 
  93     private class HeapRegionIterator implements Iterator<HeapRegion> {
  94         private long index;
  95         private long length;
  96         private HeapRegion next;
  97 
  98         public HeapRegion positionToNext() {
  99           HeapRegion result = next;
 100           while (index < length && at(index) == null) {
 101             index++;
 102           }
 103           if (index < length) {
 104             next = at(index);
 105             index++; // restart search at next element
 106           } else {
 107             next = null;
 108           }
 109           return result;
 110         }
 111 
 112         @Override
 113         public boolean hasNext() { return next != null;     }
 114 
 115         @Override
 116         public HeapRegion next() { return positionToNext(); }
 117 
 118         @Override
 119         public void remove()     { /* not supported */      }
 120 
 121         HeapRegionIterator(long totalLength) {
 122             index = 0;
 123             length = totalLength;
 124             positionToNext();
 125         }
 126     }
 127 
 128     public Iterator<HeapRegion> heapRegionIterator(long committedLength) {
 129         return new HeapRegionIterator(committedLength);
 130     }
 131 
 132     public G1HeapRegionTable(Address addr) {
 133         super(addr);
 134     }
 135 }