1 /*

     2  * Copyright (c) 2012, 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 import jdk.internal.org.objectweb.asm.*;

    26 

    27 class Asmator {

    28     static byte[] fixup(byte[] buf) throws java.io.IOException {

    29         ClassReader cr = new ClassReader(buf);

    30         ClassWriter cw = new ClassWriter(0);

    31         ClassVisitor cv = new ClassVisitor(Opcodes.ASM4, cw) {

    32             public MethodVisitor visitMethod(

    33                 final int access,

    34                 final String name,

    35                 final String desc,

    36                 final String signature,

    37                 final String[] exceptions)

    38             {

    39                 MethodVisitor mv = super.visitMethod(access,

    40                         name,

    41                         desc,

    42                         signature,

    43                         exceptions);

    44                 if (mv == null)  return null;

    45                 if (name.equals("callme")) {

    46                     // make receiver go dead!

    47                     mv.visitInsn(Opcodes.ACONST_NULL);

    48                     mv.visitVarInsn(Opcodes.ASTORE, 0);

    49                 }

    50                 return mv;

    51             }

    52         };

    53         cr.accept(cv, 0);

    54         return cw.toByteArray();

    55     }

    56 }