1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.nabla.forward.instructions;
18
19 import org.apache.commons.nabla.DifferentiationException;
20 import org.apache.commons.nabla.forward.analysis.InstructionsTransformer;
21 import org.apache.commons.nabla.forward.analysis.MethodDifferentiator;
22 import org.objectweb.asm.Opcodes;
23 import org.objectweb.asm.Type;
24 import org.objectweb.asm.tree.AbstractInsnNode;
25 import org.objectweb.asm.tree.InsnList;
26 import org.objectweb.asm.tree.InsnNode;
27 import org.objectweb.asm.tree.MethodInsnNode;
28
29 /** Differentiation transformer for narrowing a derivative structure on the stack
30 * to a double.
31 * @version $Id$
32 */
33 public class NarrowingTransformer implements InstructionsTransformer {
34
35 /** Simple constructor.
36 */
37 public NarrowingTransformer() {
38 }
39
40 /** {@inheritDoc} */
41 public InsnList getReplacement(final AbstractInsnNode insn,
42 final MethodDifferentiator methodDifferentiator)
43 throws DifferentiationException {
44
45 final InsnList list = new InsnList();
46
47 list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, DS_TYPE.getInternalName(),
48 "getValue",
49 Type.getMethodDescriptor(Type.DOUBLE_TYPE)));
50
51 // copy the instruction consuming the double (D2I, D2L or D2F)
52 list.add(new InsnNode(insn.getOpcode()));
53
54 return list;
55
56 }
57
58 }