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 ch7.sec2;
30:
31: import org.objectweb.asm.MethodAdapter;
32: import org.objectweb.asm.MethodVisitor;
33: import org.objectweb.asm.tree.AbstractInsnNode;
34: import org.objectweb.asm.tree.LabelNode;
35: import org.objectweb.asm.tree.MethodNode;
36: import org.objectweb.asm.tree.analysis.Analyzer;
37: import org.objectweb.asm.tree.analysis.AnalyzerException;
38: import org.objectweb.asm.tree.analysis.BasicInterpreter;
39: import org.objectweb.asm.tree.analysis.Frame;
40:
41: /**
42: * ASM Guide example class.
43: *
44: * @author Eric Bruneton
45: */
46: public class RemoveDeadCodeAdapter extends MethodAdapter {
47:
48: String owner;
49:
50: MethodVisitor next;
51:
52: public RemoveDeadCodeAdapter(String owner, int access, String name,
53: String desc, MethodVisitor mv) {
54: super (new MethodNode(access, name, desc, null, null));
55: this .owner = owner;
56: next = mv;
57: }
58:
59: public void visitEnd() {
60: MethodNode mn = (MethodNode) mv;
61: Analyzer a = new Analyzer(new BasicInterpreter());
62: try {
63: a.analyze(owner, mn);
64: Frame[] frames = a.getFrames();
65: AbstractInsnNode[] insns = mn.instructions.toArray();
66: for (int i = 0; i < frames.length; ++i) {
67: if (frames[i] == null
68: && !(insns[i] instanceof LabelNode)) {
69: mn.instructions.remove(insns[i]);
70: }
71: }
72: } catch (AnalyzerException ignored) {
73: }
74: mn.accept(next);
75: }
76: }
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