001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.commons.nabla.forward.instructions; 018 019 import org.apache.commons.nabla.DifferentiationException; 020 import org.apache.commons.nabla.forward.analysis.InstructionsTransformer; 021 import org.apache.commons.nabla.forward.analysis.MethodDifferentiator; 022 import org.objectweb.asm.Opcodes; 023 import org.objectweb.asm.tree.AbstractInsnNode; 024 import org.objectweb.asm.tree.InsnList; 025 import org.objectweb.asm.tree.InsnNode; 026 027 /** Differentiation transformer for DUP2 instructions. 028 * <p>DUP2 instructions are replaced by DUP instructions 029 * as a reference to a {@link 030 * org.apache.commons.math3.analysis.differentiation.DerivativeStructure} 031 * instance uses only one stack slot instead of two.</p> 032 * @version $Id$ 033 */ 034 public class Dup2Transformer implements InstructionsTransformer { 035 036 /** Simple constructor. 037 */ 038 public Dup2Transformer() { 039 } 040 041 /** {@inheritDoc} */ 042 public InsnList getReplacement(final AbstractInsnNode insn, 043 final MethodDifferentiator methodDifferentiator) 044 throws DifferentiationException { 045 046 final InsnList list = new InsnList(); 047 list.add(new InsnNode(Opcodes.DUP)); 048 return list; 049 050 } 051 052 }