/***
* ASM Guide
* Copyright (c) 2007 Eric Bruneton
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
package ch7.sec2;
import org.objectweb.asm.MethodAdapter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.tree.AbstractInsnNode;
import org.objectweb.asm.tree.LabelNode;
import org.objectweb.asm.tree.MethodNode;
import org.objectweb.asm.tree.analysis.Analyzer;
import org.objectweb.asm.tree.analysis.AnalyzerException;
import org.objectweb.asm.tree.analysis.BasicInterpreter;
import org.objectweb.asm.tree.analysis.Frame;
/**
* ASM Guide example class.
*
* @author Eric Bruneton
*/
public class RemoveDeadCodeAdapter extends MethodAdapter {
String owner;
MethodVisitor next;
public RemoveDeadCodeAdapter(String owner, int access, String name,
String desc, MethodVisitor mv) {
super(new MethodNode(access, name, desc, null, null));
this.owner = owner;
next = mv;
}
public void visitEnd() {
MethodNode mn = (MethodNode) mv;
Analyzer a = new Analyzer(new BasicInterpreter());
try {
a.analyze(owner, mn);
Frame[] frames = a.getFrames();
AbstractInsnNode[] insns = mn.instructions.toArray();
for (int i = 0; i < frames.length; ++i) {
if (frames[i] == null && !(insns[i] instanceof LabelNode)) {
mn.instructions.remove(insns[i]);
}
}
} catch (AnalyzerException ignored) {
}
mn.accept(next);
}
}