1 /*
   2  * Copyright (c) 2013, 2017, 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.debugger.OopHandle;
  33 import sun.jvm.hotspot.runtime.VM;
  34 import sun.jvm.hotspot.runtime.VMObject;
  35 import sun.jvm.hotspot.runtime.VMObjectFactory;
  36 import sun.jvm.hotspot.types.AddressField;
  37 import sun.jvm.hotspot.types.CIntegerField;
  38 import sun.jvm.hotspot.types.Type;
  39 import sun.jvm.hotspot.types.TypeDataBase;
  40 
  41 // Mirror class for G1HeapRegionTable. It's essentially an index -> HeapRegion map.
  42 
  43 public class G1HeapRegionTable extends VMObject {
  44     // HeapRegion** _base;
  45     static private AddressField baseField;
  46     // uint _length;
  47     static private CIntegerField lengthField;
  48     // HeapRegion** _biased_base
  49     static private AddressField biasedBaseField;
  50     // size_t _bias
  51     static private CIntegerField biasField;
  52     // uint _shift_by
  53     static private CIntegerField shiftByField;
  54 
  55     static {
  56         VM.registerVMInitializedObserver(new Observer() {
  57                 public void update(Observable o, Object data) {
  58                     initialize(VM.getVM().getTypeDataBase());
  59                 }
  60             });
  61     }
  62 
  63     static private synchronized void initialize(TypeDataBase db) {
  64         Type type = db.lookupType("G1HeapRegionTable");
  65 
  66         baseField = type.getAddressField("_base");
  67         lengthField = type.getCIntegerField("_length");
  68         biasedBaseField = type.getAddressField("_biased_base");
  69         biasField = type.getCIntegerField("_bias");
  70         shiftByField = type.getCIntegerField("_shift_by");
  71     }
  72 
  73     private HeapRegion at(long index) {
  74         Address arrayAddr = baseField.getValue(addr);
  75         // Offset of &_base[index]
  76         long offset = index * VM.getVM().getAddressSize();
  77         Address regionAddr = arrayAddr.getAddressAt(offset);
  78         return (HeapRegion) VMObjectFactory.newObject(HeapRegion.class,
  79                                                       regionAddr);
  80     }
  81 
  82     public long length() {
  83         return lengthField.getValue(addr);
  84     }
  85 
  86     public long bias() {
  87         return biasField.getValue(addr);
  88     }
  89 
  90     public long shiftBy() {
  91         return shiftByField.getValue(addr);
  92     }
  93 
  94     private class HeapRegionIterator implements Iterator<HeapRegion> {
  95         private long index;
  96         private long length;
  97         private HeapRegion next;
  98 
  99         public HeapRegion positionToNext() {
 100           HeapRegion result = next;
 101           while (index < length && at(index) == null) {
 102             index++;
 103           }
 104           if (index < length) {
 105             next = at(index);
 106             index++; // restart search at next element
 107           } else {
 108             next = null;
 109           }
 110           return result;
 111         }
 112 
 113         @Override
 114         public boolean hasNext() { return next != null;     }
 115 
 116         @Override
 117         public HeapRegion next() { return positionToNext(); }
 118 
 119         @Override
 120         public void remove()     { /* not supported */      }
 121 
 122         HeapRegionIterator(long totalLength) {
 123             index = 0;
 124             length = totalLength;
 125             positionToNext();
 126         }
 127     }
 128 
 129     public Iterator<HeapRegion> heapRegionIterator(long committedLength) {
 130         return new HeapRegionIterator(committedLength);
 131     }
 132 
 133     public G1HeapRegionTable(Address addr) {
 134         super(addr);
 135     }
 136 
 137     public HeapRegion getByAddress(Address target) {
 138         Address arrayAddr = biasedBaseField.getValue(addr);
 139         long biasedIndex = target.asLongValue() >>> shiftBy();
 140         long offset = biasedIndex * HeapRegion.getPointerSize();
 141         Address regionAddr = arrayAddr.getAddressAt(offset);
 142         return (HeapRegion)VMObjectFactory.newObject(HeapRegion.class, regionAddr);

 143     }
 144 }
--- EOF ---