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.algorithmic.forward.arithmetic; 018 019 import org.apache.commons.nabla.algorithmic.forward.analysis.InstructionsTransformer; 020 import org.apache.commons.nabla.algorithmic.forward.analysis.MethodDifferentiator; 021 import org.apache.commons.nabla.core.DifferentiationException; 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 import org.objectweb.asm.tree.VarInsnNode; 027 028 /** Differentiation transformer for DNEG instructions. 029 */ 030 public class DNegTransformer implements InstructionsTransformer { 031 032 // CHECKSTYLE: stop HideUtilityClassConstructor 033 /** Holder for the singleton instance.*/ 034 private static class LazyHolder { 035 /** The singleton instance. */ 036 private static final InstructionsTransformer INSTANCE = new DNegTransformer(); 037 } 038 // CHECKSTYLE: resume HideUtilityClassConstructor 039 040 /** Hidden constructor. 041 */ 042 private DNegTransformer() { 043 } 044 045 /** Get the singleton instance. 046 * <p>We use here the Initialization on Demand Holder idiom.</p> 047 * @return the singleton instance 048 */ 049 public static InstructionsTransformer getInstance() { 050 return LazyHolder.INSTANCE; 051 } 052 053 /** {@inheritDoc} */ 054 public InsnList getReplacement(final AbstractInsnNode insn, 055 final MethodDifferentiator methodDifferentiator) 056 throws DifferentiationException { 057 058 final int tmp = methodDifferentiator.getTmp(1); 059 final InsnList list = new InsnList(); 060 061 list.add(new VarInsnNode(Opcodes.DSTORE, tmp)); 062 list.add(new InsnNode(Opcodes.DNEG)); 063 list.add(new VarInsnNode(Opcodes.DLOAD, tmp)); 064 list.add(new InsnNode(Opcodes.DNEG)); 065 066 return list; 067 068 } 069 070 }