com.sun.btrace.runtime.MethodEntryInstrumentor Maven / Gradle / Ivy

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/*
 * Copyright 2008-2010 Sun Microsystems, Inc.  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.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package com.sun.btrace.runtime;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import com.sun.btrace.org.objectweb.asm.ClassReader;
import com.sun.btrace.org.objectweb.asm.ClassVisitor;
import com.sun.btrace.org.objectweb.asm.ClassWriter;
import com.sun.btrace.org.objectweb.asm.MethodVisitor;
import com.sun.btrace.org.objectweb.asm.Opcodes;
import static com.sun.btrace.org.objectweb.asm.Opcodes.*;
import static com.sun.btrace.runtime.Constants.CONSTRUCTOR;

/**
 * This visitor helps in inserting code whenever a method 
 * is entered. The code to insert on method entry may be 
 * decided by derived class. By default, this class inserts 
 * code to print name and signature of the method entered.
 *
 * @author A. Sundararajan
 */
public class MethodEntryInstrumentor extends MethodInstrumentor {
    private boolean entryCalled = false;
    public MethodEntryInstrumentor(MethodVisitor mv, String parentClz, String superClz,
        int access, String name, String desc) {
        super(mv, parentClz, superClz, access, name, desc);
    }

    public void visitCode() {
        if (!isConstructor()) {
            entryCalled = true;
            onMethodEntry();
        }
        super.visitCode();
    }

    public void visitMethodInsn(int opcode,
                     String owner,
                     String name,
                     String desc) {        
        super.visitMethodInsn(opcode, owner, name, desc);
        if (isConstructor() && !entryCalled) {
            if (name.equals(CONSTRUCTOR) && (owner.equals(getParentClz()) || (getSuperClz() != null && owner.equals(getSuperClz())))) {
                // super or this class constructor call.
                // do method entry after that!
                entryCalled = true;
                onMethodEntry();
            }
        }
    }       

    public void visitInsn(int opcode) {
        switch (opcode) {
            case IRETURN:
            case ARETURN:
            case FRETURN:                           
            case LRETURN:
            case DRETURN:
            case RETURN:
                if (!entryCalled) {
                    entryCalled = true;
                    onMethodEntry();
                }
                break;
            default:                           
                break;
        }
        super.visitInsn(opcode);
    }

    protected void onMethodEntry() {
        println("entering " + getName() + getDescriptor());
    }

    public static void main(final String[] args) throws Exception {
        if (args.length != 1) {
            System.err.println("Usage: java com.sun.btrace.runtime.MethodEntryInstrumentor ");
            System.exit(1);
        }

        args[0] = args[0].replace('.', '/');
        FileInputStream fis = new FileInputStream(args[0] + ".class");
        ClassReader reader = new ClassReader(new BufferedInputStream(fis));
        FileOutputStream fos = new FileOutputStream(args[0] + ".class");
        ClassWriter writer = InstrumentUtils.newClassWriter();
        InstrumentUtils.accept(reader, 
            new ClassVisitor(Opcodes.ASM4, writer) {
                 public MethodVisitor visitMethod(int access, String name, String desc, 
                     String signature, String[] exceptions) {
                     MethodVisitor mv = super.visitMethod(access, name, desc, 
                             signature, exceptions);
                     return new MethodEntryInstrumentor(mv, args[0], args[0], access, name, desc);
                 }
            });
        fos.write(writer.toByteArray());
    }
}