1 /* 2 * Copyright (c) 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.Observable; 28 import java.util.Observer; 29 import sun.jvm.hotspot.debugger.Address; 30 import sun.jvm.hotspot.runtime.VM; 31 import sun.jvm.hotspot.runtime.VMObject; 32 import sun.jvm.hotspot.types.CIntegerField; 33 import sun.jvm.hotspot.types.Type; 34 import sun.jvm.hotspot.types.TypeDataBase; 35 36 // Mirror class for HeapRegionType. Currently we don't actually include 37 // any of its fields but only iterate over it. 38 39 public class HeapRegionType extends VMObject { 40 41 private static int freeTag; 42 43 private static int youngMask; 44 45 private static int humongousMask; 46 47 private static int pinnedMask; 48 49 private static int oldMask; 50 51 private static CIntegerField tagField; 52 53 private int tag; 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 private static synchronized void initialize(TypeDataBase db) { 64 Type type = db.lookupType("HeapRegionType"); 65 66 tagField = type.getCIntegerField("_tag"); 67 68 youngMask = db.lookupIntConstant("HeapRegionType::YoungMask"); 69 humongousMask = db.lookupIntConstant("HeapRegionType::HumongousMask"); 70 oldMask = db.lookupIntConstant("HeapRegionType::OldMask"); 71 } 72 73 public boolean isFree() { 74 return tagField.getValue(addr) == freeTag; 75 } 76 77 public boolean isYoung() { 78 return (tagField.getValue(addr) & youngMask) != 0; 79 } 80 81 public boolean isHumongous() { 82 return (tagField.getValue(addr) & humongousMask) != 0; 83 } 84 85 public boolean isPinned() { 86 return (tagField.getValue(addr) & pinnedMask) != 0; 87 } 88 89 public boolean isOld() { 90 return (tagField.getValue(addr) & oldMask) != 0; 91 } 92 93 public HeapRegionType(Address addr) { 94 super(addr); 95 } 96 }