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Java > Open Source Codes > org > aspectj > compiler > base > FrameLocPass


1 /* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
2  *
3  * This file is part of the compiler and core tools for the AspectJ(tm)
4  * programming language; see http://aspectj.org
5  *
6  * The contents of this file are subject to the Mozilla Public License
7  * Version 1.1 (the "License"); you may not use this file except in
8  * compliance with the License. You may obtain a copy of the License at
9  * either http://www.mozilla.org/MPL/ or http://aspectj.org/MPL/.
10  *
11  * Software distributed under the License is distributed on an "AS IS" basis,
12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13  * for the specific language governing rights and limitations under the
14  * License.
15  *
16  * The Original Code is AspectJ.
17  *
18  * The Initial Developer of the Original Code is Xerox Corporation. Portions
19  * created by Xerox Corporation are Copyright (C) 1999-2002 Xerox Corporation.
20  * All Rights Reserved.
21  *
22  * Contributor(s):
23  */
24
25 package org.aspectj.compiler.base;
26
27 import org.aspectj.compiler.base.ast.*;
28 import org.aspectj.compiler.base.*;
29
30 import java.util.*;
31
32 // This pass assigns frame locations to VarDecs, finally parts of
33 // TryStmts, and synchronizeBlocks. The finally parts of TryStmts and
34 // synchronize blocks need two frame locations: one for the (possible)
35 // exception thrown, and one for the return pc for the JSR part.
36 // It also sets the max frame size for MethodDecs.
37
38 // This must be run after all local classes are lifted.
39
40 // This is _totally_ a non-structure-effecting visitor pass.
41
42 public final class FrameLocPass extends WalkerPass {
43     public FrameLocPass(JavaCompiler jc) { super(jc); }
44     
45     public String JavaDoc getDisplayName() { return "assigning frame locs"; }
46
47     public boolean inTryFinally = false;
48     private int maxfs = 0;
49     private int fs = 0;
50
51     // ------------------------------
52 // stack and frame
53
54     public int getmaxfs() {
55         return maxfs;
56     }
57     public int getfs() {
58         return fs;
59     }
60     public void setfs(int fs) {
61         if (! inTryFinally)
62             this.fs = fs;
63         frameInvariant();
64     }
65     public void incfs(int delta) {
66         this.fs += delta;
67         frameInvariant();
68     }
69     public int allocate(int size) {
70         int ret = this.fs;
71         incfs(size);
72         return ret;
73     }
74     private void frameInvariant() {
75         if (fs > maxfs) maxfs = fs;
76     }
77
78     public ASTObject process(ASTObject object) {
79         object.walkFrameLoc(this);
80         return object;
81     }
82 }
83
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