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 import sun.jvm.hotspot.utilities.Assert; 41 42 // Mirror class for G1HeapRegionTable. It's essentially an index -> HeapRegion map. 43 44 public class G1HeapRegionTable extends VMObject { 45 // HeapRegion** _base; 46 static private AddressField baseField; 47 // uint _length; 48 static private CIntegerField lengthField; 49 // HeapRegion** _biased_base 50 static private AddressField biasedBaseField; 51 // size_t _bias 52 static private CIntegerField biasField; 53 // uint _shift_by 54 static private CIntegerField shiftByField; 55 56 static { 57 VM.registerVMInitializedObserver(new Observer() { 58 public void update(Observable o, Object data) { 59 initialize(VM.getVM().getTypeDataBase()); 60 } 61 }); 62 } 63 64 static private synchronized void initialize(TypeDataBase db) { 65 Type type = db.lookupType("G1HeapRegionTable"); 66 67 baseField = type.getAddressField("_base"); 68 lengthField = type.getCIntegerField("_length"); 69 biasedBaseField = type.getAddressField("_biased_base"); 70 biasField = type.getCIntegerField("_bias"); 71 shiftByField = type.getCIntegerField("_shift_by"); 72 } 73 74 private HeapRegion at(long index) { 75 Address arrayAddr = baseField.getValue(addr); 76 // Offset of &_base[index] 77 long offset = index * VM.getVM().getAddressSize(); 78 Address regionAddr = arrayAddr.getAddressAt(offset); 79 return (HeapRegion) VMObjectFactory.newObject(HeapRegion.class, 80 regionAddr); 81 } 82 83 public long length() { 84 return lengthField.getValue(addr); 85 } 86 87 public long bias() { 88 return biasField.getValue(addr); 89 } 90 91 public long shiftBy() { 92 return shiftByField.getValue(addr); 93 } 94 95 private class HeapRegionIterator implements Iterator<HeapRegion> { 96 private long index; 97 private long length; 98 private HeapRegion next; 99 100 public HeapRegion positionToNext() { 101 HeapRegion result = next; 102 while (index < length && at(index) == null) { 103 index++; 104 } 105 if (index < length) { 106 next = at(index); 107 index++; // restart search at next element 108 } else { 109 next = null; 110 } 111 return result; 112 } 113 114 @Override 115 public boolean hasNext() { return next != null; } 116 117 @Override 118 public HeapRegion next() { return positionToNext(); } 119 120 @Override 121 public void remove() { /* not supported */ } 122 123 HeapRegionIterator(long totalLength) { 124 index = 0; 125 length = totalLength; 126 positionToNext(); 127 } 128 } 129 130 public Iterator<HeapRegion> heapRegionIterator(long committedLength) { 131 return new HeapRegionIterator(committedLength); 132 } 133 134 public G1HeapRegionTable(Address addr) { 135 super(addr); 136 } 137 138 public HeapRegion getByAddress(Address addr) { 139 if (Assert.ASSERTS_ENABLED) { 140 Assert.that(addr instanceof OopHandle, "addr should be OopHandle"); 141 } 142 143 long biasedIndex = addr.asLongValue() >>> shiftBy(); 144 return new HeapRegion(addr.addOffsetToAsOopHandle( 145 biasedIndex * HeapRegion.getPointerSize())); 146 } 147 }