Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
SwappedDstoreTrimmer |
|
| 4.0;4 |
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.trimming; | |
18 | ||
19 | import org.objectweb.asm.Opcodes; | |
20 | import org.objectweb.asm.tree.AbstractInsnNode; | |
21 | import org.objectweb.asm.tree.InsnList; | |
22 | import org.objectweb.asm.tree.VarInsnNode; | |
23 | ||
24 | /** Trimmer replacing (DUP2_X2, POP2, DSTORE i, DSTORE j) with (DSTORE j, DSTORE i). | |
25 | * @version $Id$ | |
26 | */ | |
27 | public class SwappedDstoreTrimmer extends BytecodeTrimmer { | |
28 | ||
29 | /** Simple constructor. | |
30 | */ | |
31 | public SwappedDstoreTrimmer() { | |
32 | 66 | super(4); |
33 | 66 | } |
34 | ||
35 | /** {@inheritDoc} */ | |
36 | @Override | |
37 | protected boolean trimWindow(final InsnList instructions, | |
38 | final AbstractInsnNode[] window) { | |
39 | ||
40 | 217 | if ((window[0].getOpcode() == Opcodes.DUP2_X2) && |
41 | (window[1].getOpcode() == Opcodes.POP2) && | |
42 | (window[2].getOpcode() == Opcodes.DSTORE) && | |
43 | (window[3].getOpcode() == Opcodes.DSTORE)) { | |
44 | ||
45 | // reverse the DSTORE orders | |
46 | 0 | final int tmp = ((VarInsnNode) window[2]).var; |
47 | 0 | ((VarInsnNode) window[2]).var = ((VarInsnNode) window[3]).var; |
48 | 0 | ((VarInsnNode) window[3]).var = tmp; |
49 | ||
50 | // remove the operand stack swap instructions | |
51 | 0 | instructions.remove(window[0]); |
52 | 0 | instructions.remove(window[1]); |
53 | ||
54 | // update lookahead instructions | |
55 | 0 | window[0] = window[2]; |
56 | 0 | window[1] = window[3]; |
57 | 0 | window[2] = window[1].getNext(); |
58 | 0 | window[3] = (window[2] == null) ? null : window[2].getNext(); |
59 | 0 | return true; |
60 | ||
61 | } | |
62 | ||
63 | // nothing have been done | |
64 | 217 | return false; |
65 | ||
66 | } | |
67 | ||
68 | } |