1 /*

     2  * Copyright (c) 2015, 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.compiler;

    26 

    27 import sun.jvm.hotspot.debugger.Address;

    28 import sun.jvm.hotspot.runtime.VM;

    29 import sun.jvm.hotspot.types.CIntegerField;

    30 import sun.jvm.hotspot.types.Type;

    31 import sun.jvm.hotspot.types.TypeDataBase;

    32 

    33 import java.util.Observable;

    34 import java.util.Observer;

    35 

    36 public class ImmutableOopMapPair {

    37   private static CIntegerField pcField;

    38   private static CIntegerField offsetField;

    39   private static long classSize;

    40 

    41   static {

    42     VM.registerVMInitializedObserver(new Observer() {

    43       public void update(Observable o, Object data) {

    44         initialize(VM.getVM().getTypeDataBase());

    45       }

    46     });

    47   }

    48 

    49   private final Address address;

    50 

    51   public ImmutableOopMapPair(Address address) {

    52     this.address = address;

    53   }

    54 

    55   public static long classSize() {

    56     return classSize;

    57   }

    58 

    59   public int getPC() {

    60     return (int) pcField.getValue(address);

    61   }

    62 

    63   public int getOffset() {

    64     return (int) offsetField.getValue(address);

    65   }

    66 

    67   private static void initialize(TypeDataBase db) {

    68     Type type = db.lookupType("ImmutableOopMapSet");

    69 

    70     pcField = type.getCIntegerField("_pc_offset");

    71     offsetField = type.getCIntegerField("_oopmap_offset");

    72     classSize = type.getSize();

    73   }

    74 }