1 /*

     2  * Copyright (c) 2011, 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.code;

    26 

    27 import java.util.*;

    28 import sun.jvm.hotspot.debugger.*;

    29 import sun.jvm.hotspot.runtime.*;

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

    31 

    32 /** RicochetBlob (currently only used by Compiler 2) */

    33 

    34 public class RicochetBlob extends SingletonBlob {

    35   static {

    36     VM.registerVMInitializedObserver(new Observer() {

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

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

    39         }

    40       });

    41   }

    42 

    43   private static void initialize(TypeDataBase db) {

    44     Type type = db.lookupType("RicochetBlob");

    45 

    46     bounceOffsetField                = type.getCIntegerField("_bounce_offset");

    47     exceptionOffsetField             = type.getCIntegerField("_exception_offset");

    48   }

    49 

    50   private static CIntegerField bounceOffsetField;

    51   private static CIntegerField exceptionOffsetField;

    52 

    53   public RicochetBlob(Address addr) {

    54     super(addr);

    55   }

    56 

    57   public boolean isRicochetBlob() {

    58     return true;

    59   }

    60 

    61   public Address bounceAddr() {

    62     return codeBegin().addOffsetTo(bounceOffsetField.getValue(addr));

    63   }

    64 

    65   public boolean returnsToBounceAddr(Address pc) {

    66     Address bouncePc = bounceAddr();

    67     return (pc.equals(bouncePc) || pc.addOffsetTo(Frame.pcReturnOffset()).equals(bouncePc));

    68   }

    69 

    70 }