de.tuberlin.uebb.jbop.optimizer.loop.ForLoopBody.java Source code

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Here is the source code for de.tuberlin.uebb.jbop.optimizer.loop.ForLoopBody.java

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/*
 * Copyright (C) 2013 uebb.tu-berlin.de.
 * 
 * This file is part of JBOP (Java Bytecode OPtimizer).
 * 
 * JBOP is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * JBOP 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 Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with JBOP. If not, see <http://www.gnu.org/licenses/>.
 */
package de.tuberlin.uebb.jbop.optimizer.loop;

import java.util.List;

import org.objectweb.asm.Opcodes;
import org.objectweb.asm.tree.AbstractInsnNode;
import org.objectweb.asm.tree.InsnList;
import org.objectweb.asm.tree.MethodNode;
import org.objectweb.asm.tree.VarInsnNode;

import de.tuberlin.uebb.jbop.optimizer.LabelMap;
import de.tuberlin.uebb.jbop.optimizer.utils.NodeHelper;

/**
 * The Class ForLoopBody.
 * 
 * This DTO stores the body of the loop.
 * 
 * It provides the instructions of the body in
 * respect to the 'current' counter variable.
 * 
 * @author Christopher Ewest
 */
public class ForLoopBody {

    private final List<AbstractInsnNode> body;

    /**
     * Instantiates a new for loop body.
     * 
     * @param body
     *          the body
     */
    public ForLoopBody(final List<AbstractInsnNode> body) {
        super();
        this.body = body;
    }

    /**
     * Gets the body.
     * 
     * @return the body
     */
    public List<AbstractInsnNode> getBody() {
        return body;
    }

    /**
     * Gets the insn list.
     * 
     * @param i
     *          the curretn counter
     * @param footer
     *          the footer
     * @param method
     *          the method
     * @return the insn list of the body in respect to the current counter (<code>i</code>).
     */
    public InsnList getInsnList(final int i, final ForLoopFooter footer, final MethodNode method) {
        final InsnList list = new InsnList();
        if (body.isEmpty()) {
            return list;
        }
        final LabelMap labelMap = new LabelMap();
        final int newLocalVar = method.maxLocals + 1;
        final int oldLocalVar = footer.getVarIndex();
        list.add(NodeHelper.getInsnNodeFor(i));
        list.add(new VarInsnNode(Opcodes.ISTORE, newLocalVar));
        for (final AbstractInsnNode node : body) {
            final AbstractInsnNode copyNode = node.clone(labelMap);
            if (copyNode instanceof VarInsnNode) {
                if (((VarInsnNode) copyNode).var == oldLocalVar) {
                    ((VarInsnNode) copyNode).var = newLocalVar;
                }
            }
            list.add(copyNode);
        }
        list.add(new SplitMarkNode());
        method.maxLocals++;
        return list;
    }

}