01: /***
02: * ASM Guide
03: * Copyright (c) 2007 Eric Bruneton
04: * All rights reserved.
05: *
06: * Redistribution and use in source and binary forms, with or without
07: * modification, are permitted provided that the following conditions
08: * are met:
09: * 1. Redistributions of source code must retain the above copyright
10: * notice, this list of conditions and the following disclaimer.
11: * 2. Redistributions in binary form must reproduce the above copyright
12: * notice, this list of conditions and the following disclaimer in the
13: * documentation and/or other materials provided with the distribution.
14: * 3. Neither the name of the copyright holders nor the names of its
15: * contributors may be used to endorse or promote products derived from
16: * this software without specific prior written permission.
17: *
18: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19: * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21: * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
22: * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
28: * THE POSSIBILITY OF SUCH DAMAGE.
29: */package ch3.sec2;
30:
31: import static org.objectweb.asm.Opcodes.ALOAD;
32: import static org.objectweb.asm.Opcodes.ASTORE;
33: import static org.objectweb.asm.Opcodes.ILOAD;
34: import static org.objectweb.asm.Opcodes.ISTORE;
35:
36: import org.objectweb.asm.MethodVisitor;
37:
38: /**
39: * ASM Guide example class.
40: *
41: * @author Eric Bruneton
42: */
43: public class RemoveLoadStoreAdapter extends PatternMethodAdapter {
44:
45: private static int SEEN_LOAD = 1;
46:
47: private int varType;
48:
49: private int varIndex;
50:
51: public RemoveLoadStoreAdapter(MethodVisitor mv) {
52: super (mv);
53: }
54:
55: public void visitVarInsn(int opcode, int var) {
56: if (state == SEEN_LOAD) {
57: if (opcode >= ISTORE && opcode <= ASTORE) {
58: if (opcode - ISTORE == varType && var == varIndex) {
59: state = SEEN_NOTHING;
60: return;
61: }
62: }
63: }
64: visitInsn();
65: if (opcode >= ILOAD && opcode <= ALOAD) {
66: state = SEEN_LOAD;
67: varType = opcode - ILOAD;
68: varIndex = var;
69: return;
70: }
71: mv.visitVarInsn(opcode, var);
72: }
73:
74: protected void visitInsn() {
75: if (state == SEEN_LOAD) {
76: mv.visitVarInsn(varType + ILOAD, varIndex);
77: }
78: state = SEEN_NOTHING;
79: }
80: }
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