/*

 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

package sun.jvm.hotspot.compiler;

import sun.jvm.hotspot.debugger.Address;

import sun.jvm.hotspot.runtime.VM;

import sun.jvm.hotspot.types.CIntegerField;

import sun.jvm.hotspot.types.Type;

import sun.jvm.hotspot.types.TypeDataBase;

import java.util.Observable;

import java.util.Observer;

public class ImmutableOopMapPair {

  private static CIntegerField pcField;

  private static CIntegerField offsetField;

  private static long classSize;

  static {

    VM.registerVMInitializedObserver(new Observer() {

      public void update(Observable o, Object data) {

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

      }

    });

  }

  private final Address address;

  public ImmutableOopMapPair(Address address) {

    this.address = address;

  }

  public static long classSize() {

    return classSize;

  }

  public int getPC() {

    return (int) pcField.getValue(address);

  }

  public int getOffset() {

    return (int) offsetField.getValue(address);

  }

  private static void initialize(TypeDataBase db) {

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

    pcField = type.getCIntegerField("_pc_offset");

    offsetField = type.getCIntegerField("_oopmap_offset");

    classSize = type.getSize();

  }

}