1 /* 2 * Copyright (c) 2018, 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.z; 26 27 import sun.jvm.hotspot.debugger.Address; 28 import sun.jvm.hotspot.runtime.VM; 29 import sun.jvm.hotspot.runtime.VMObject; 30 import sun.jvm.hotspot.runtime.VMObjectFactory; 31 import sun.jvm.hotspot.types.CIntegerField; 32 import sun.jvm.hotspot.types.Type; 33 import sun.jvm.hotspot.types.TypeDataBase; 34 35 class ZPage extends VMObject { 36 private static CIntegerField typeField; 37 private static long virtualFieldOffset; 38 private static long forwardingFieldOffset; 39 private static byte ZPageTypeSmall; 40 private static byte ZPageTypeMedium; 41 private static byte ZPageTypeLarge; 42 private static int ZObjectAlignmentSmallShift; 43 private static int ZObjectAlignmentMediumShift; 44 private static int ZObjectAlignmentLargeShift; 45 46 static { 47 VM.registerVMInitializedObserver((o, d) -> initialize(VM.getVM().getTypeDataBase())); 48 } 49 50 static private synchronized void initialize(TypeDataBase db) { 51 Type type = db.lookupType("ZPage"); 52 53 typeField = type.getCIntegerField("_type"); 54 virtualFieldOffset = type.getField("_virtual").getOffset(); 55 forwardingFieldOffset = type.getField("_forwarding").getOffset(); 56 57 ZPageTypeSmall = db.lookupIntConstant("ZPageTypeSmall").byteValue(); 58 ZPageTypeMedium = db.lookupIntConstant("ZPageTypeMedium").byteValue(); 59 ZPageTypeLarge = db.lookupIntConstant("ZPageTypeLarge").byteValue(); 60 ZObjectAlignmentSmallShift = db.lookupIntConstant("ZObjectAlignmentSmallShift").intValue(); 61 ZObjectAlignmentMediumShift = db.lookupIntConstant("ZObjectAlignmentMediumShift").intValue(); 62 ZObjectAlignmentLargeShift = db.lookupIntConstant("ZObjectAlignmentLargeShift").intValue(); 63 } 64 65 ZPage(Address addr) { 66 super(addr); 67 } 68 69 private byte type() { 70 return typeField.getJByte(addr); 71 } 72 73 private ZVirtualMemory virtual() { 74 return (ZVirtualMemory)VMObjectFactory.newObject(ZVirtualMemory.class, addr.addOffsetTo(virtualFieldOffset)); 75 } 76 77 private ZForwardingTable forwarding() { 78 return (ZForwardingTable)VMObjectFactory.newObject(ZForwardingTable.class, addr.addOffsetTo(forwardingFieldOffset)); 79 } 80 81 private long start() { 82 return virtual().start(); 83 } 84 85 Address forward_object(Address from) { 86 // Lookup address in forwarding table 87 long from_offset = ZAddress.offset(from).asLongValue(); 88 long from_index = (from_offset - start()) >> object_alignment_shift(); 89 ZForwardingTableEntry entry = forwarding().find(from_index); 90 assert(!entry.is_empty()); 91 assert(entry.from_index() == from_index); 92 93 return ZAddress.good(entry.to_offset()); 94 } 95 96 Address relocate_object(Address from) { 97 // Lookup address in forwarding table 98 long from_offset = ZAddress.offset(from).asLongValue(); 99 long from_index = (from_offset - start()) >> object_alignment_shift(); 100 ZForwardingTableEntry entry = forwarding().find(from_index); 101 if (!entry.is_empty() && entry.from_index() == from_index) { 102 return ZAddress.good(entry.to_offset()); 103 } 104 105 // There's no relocate operation in the SA. 106 return ZAddress.good(from); 107 } 108 109 110 long object_alignment_shift() { 111 if (type() == ZPageTypeSmall) { 112 return ZObjectAlignmentSmallShift; 113 } else if (type() == ZPageTypeMedium) { 114 return ZObjectAlignmentMediumShift; 115 } else { 116 assert(type() == ZPageTypeLarge); 117 return ZObjectAlignmentLargeShift; 118 } 119 } 120 }