Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
DcmpTransformer12 |
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| 1.0;1 | ||||
DcmpTransformer12$1 |
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| 1.0;1 | ||||
DcmpTransformer12$LazyHolder |
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| 1.0;1 |
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.automatic.instructions; | |
18 | ||
19 | import org.apache.commons.nabla.automatic.analysis.InstructionsTransformer; | |
20 | import org.apache.commons.nabla.automatic.analysis.MethodDifferentiator; | |
21 | import org.apache.commons.nabla.core.DifferentiationException; | |
22 | import org.objectweb.asm.Opcodes; | |
23 | import org.objectweb.asm.tree.AbstractInsnNode; | |
24 | import org.objectweb.asm.tree.InsnList; | |
25 | import org.objectweb.asm.tree.InsnNode; | |
26 | ||
27 | /** Differentiation transformer for DCMPx instructions. | |
28 | * <p>Each DCMPx instruction is replaced by a sequence that | |
29 | * first remove the differential parts from the top stack cells | |
30 | * followed by the comparison instruction. | |
31 | */ | |
32 | 0 | public class DcmpTransformer12 implements InstructionsTransformer { |
33 | ||
34 | /** Holder for the singleton instance.*/ | |
35 | 0 | private static class LazyHolder { |
36 | /** The singleton instance. */ | |
37 | 0 | private static final InstructionsTransformer INSTANCE = new DcmpTransformer12(); |
38 | } | |
39 | ||
40 | /** Hidden constructor. | |
41 | */ | |
42 | 0 | private DcmpTransformer12() { |
43 | 0 | } |
44 | ||
45 | /** Get the singleton instance. | |
46 | * <p>We use here the Initialization on Demand Holder idiom.</p> | |
47 | * @return the singleton instance | |
48 | */ | |
49 | public static InstructionsTransformer getInstance() { | |
50 | 0 | return LazyHolder.INSTANCE; |
51 | } | |
52 | ||
53 | /** {@inheritDoc} */ | |
54 | public InsnList getReplacement(final AbstractInsnNode insn, | |
55 | final MethodDifferentiator methodDifferentiator) | |
56 | throws DifferentiationException { | |
57 | 0 | final InsnList list = new InsnList(); |
58 | // operand stack initial state: a0, a1, b0, b1 | |
59 | 0 | list.add(new InsnNode(Opcodes.POP2)); // => a0, a1, b0 |
60 | 0 | list.add(new InsnNode(Opcodes.DUP2_X2)); // => a0, b0, a1, b0 |
61 | 0 | list.add(new InsnNode(Opcodes.POP2)); // => a0, b0, a1 |
62 | 0 | list.add(new InsnNode(Opcodes.POP2)); // => a0, b0 |
63 | 0 | list.add(methodDifferentiator.clone(insn)); |
64 | 0 | return list; |
65 | } | |
66 | ||
67 | } |