1 kkz 1.1.2.1 // MRA.java, created Mon Oct 1 16:42:17 2001 by kkz
2 kkz 1.1.2.1 // Copyright (C) 2000 Karen Zee <kkz@tmi.lcs.mit.edu>
3 kkz 1.1.2.1 // Licensed under the terms of the GNU GPL; see COPYING for details.
4 kkz 1.1.2.1 package harpoon.Analysis.PreciseGC;
5 kkz 1.1.2.1
6 kkz 1.1.2.1 import harpoon.IR.Quads.Quad;
7 kkz 1.1.2.5 import harpoon.Util.Tuple;
8 kkz 1.1.2.1
9 kkz 1.1.2.1 /**
10 kkz 1.1.2.3 * <code>MRA</code> is answers the question "which
11 kkz 1.1.2.1 * <code>Temp<code>s contain the address of the most
12 kkz 1.1.2.1 * recently allocated object at this program point?"
13 kkz 1.1.2.1 *
14 kkz 1.1.2.1 * @author Karen Zee <kkz@tmi.lcs.mit.edu>
15 cananian 1.2 * @version $Id: MRA.java,v 1.2 2002/02/25 20:58:53 cananian Exp $
16 kkz 1.1.2.1 */
17 kkz 1.1.2.4 public abstract class MRA {
18 kkz 1.1.2.1
19 kkz 1.1.2.5 /** Returns a <code>Tuple</code>. The first element of the
20 kkz 1.1.2.5 * <code>Tuple</code> contains a <code>Map</code> of
21 kkz 1.1.2.5 * <code>Temp</code>s that point to the most recently
22 kkz 1.1.2.5 * allocated object at that program point, to a
23 kkz 1.1.2.5 * <code>MRAToken</code> that indicates whether the
24 kkz 1.1.2.5 * <code>Temp</code> points to the receiver object and
25 kkz 1.1.2.5 * whether the <code>Temp</code> succeeded the receiver
26 kkz 1.1.2.5 * object as the most-recently allocated. The second
27 kkz 1.1.2.5 * element of the <code>Tuple</code> is a <code>Set</code>
28 kkz 1.1.2.5 * of <code>HClass</code>es of which objects may have been
29 kkz 1.1.2.5 * allocated that are more recent.
30 kkz 1.1.2.1 */
31 kkz 1.1.2.5 public abstract Tuple mra_before(Quad q);
32 kkz 1.1.2.1
33 kkz 1.1.2.5 /** The <code>MRAToken</code> class represents the nodes
34 kkz 1.1.2.5 * on the lattice for the <code>MRA</code> analysis.
35 kkz 1.1.2.5 */
36 kkz 1.1.2.5 public static class MRAToken {
37 kkz 1.1.2.5 public static MRAToken BOTTOM = new MRAToken("Bottom");
38 kkz 1.1.2.5 public static MRAToken RCVR = new MRAToken("Receiver");
39 kkz 1.1.2.5 public static MRAToken SUCC = new MRAToken("Successor");
40 kkz 1.1.2.5 public static MRAToken TOP = new MRAToken("Top");
41 kkz 1.1.2.5
42 kkz 1.1.2.5 private final String name;
43 kkz 1.1.2.5
44 kkz 1.1.2.5 /** Creates an <code>MRAToken</code>. Modifier
45 kkz 1.1.2.5 * private since all instances should be declared
46 kkz 1.1.2.5 * and allocated here.
47 kkz 1.1.2.5 */
48 kkz 1.1.2.5 private MRAToken(String name) {
49 kkz 1.1.2.5 this.name = name;
50 kkz 1.1.2.5 }
51 kkz 1.1.2.5
52 kkz 1.1.2.5 /** Returns an <code>MRAToken</code> representing
53 kkz 1.1.2.5 * the join of <code>this</code> with the
54 kkz 1.1.2.5 * argument. This operation is symmetric, so
55 kkz 1.1.2.5 * a.join(b) == b.join(a)
56 kkz 1.1.2.5 */
57 kkz 1.1.2.5 public MRAToken join(MRAToken t) {
58 kkz 1.1.2.5 if (this == t) return this;
59 kkz 1.1.2.5 if (this == TOP) return t;
60 kkz 1.1.2.5 return BOTTOM;
61 kkz 1.1.2.5 }
62 kkz 1.1.2.5
63 kkz 1.1.2.5 /** Returns a <code>String</code> representation
64 kkz 1.1.2.5 * of the <code>Token</code>.
65 kkz 1.1.2.5 */
66 kkz 1.1.2.5 public String toString() {
67 kkz 1.1.2.5 return "TOKEN<"+name+">";
68 kkz 1.1.2.5 }
69 kkz 1.1.2.5 }
70 kkz 1.1.2.1 }
71 cananian 1.2