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 addr) { 138 long biasedIndex = addr.asLongValue() >>> shiftBy(); 139 long offset = biasedIndex * HeapRegion.getPointerSize(); 140 Address result = (addr instanceof OopHandle) ? addr.addOffsetToAsOopHandle(offset) 141 : addr.addOffsetTo(offset); 142 return new HeapRegion(result); 143 } 144 }