1 cananian 1.1.2.6 // TreeStackFrame.java, created Sat Mar 27 17:05:10 1999 by duncan
2 cananian 1.1.2.5 // Copyright (C) 1998 C. Scott Ananian <cananian@alumni.princeton.edu>
3 cananian 1.1.2.5 // Licensed under the terms of the GNU GPL; see COPYING for details.
4 duncan 1.1.2.1 package harpoon.Interpret.Tree;
5 duncan 1.1.2.1
6 duncan 1.1.2.1 import harpoon.ClassFile.HMethod;
7 duncan 1.1.2.1 import harpoon.IR.Tree.Exp;
8 duncan 1.1.2.1 import harpoon.IR.Tree.Stm;
9 duncan 1.1.2.2 import harpoon.IR.Tree.TEMP;
10 duncan 1.1.2.1 import harpoon.Temp.Temp;
11 duncan 1.1.2.1 import harpoon.Util.Util;
12 duncan 1.1.2.1
13 duncan 1.1.2.1 import java.util.Enumeration;
14 duncan 1.1.2.1 import java.util.Hashtable;
15 duncan 1.1.2.1
16 duncan 1.1.2.1 /**
17 duncan 1.1.2.1 * <code>TreeStackFrame</code> is a stack frame for an interpreted method.
18 duncan 1.1.2.1 *
19 duncan 1.1.2.1 * @author C. Scott Ananian <cananian@alumni.princeton.edu>
20 cananian 1.2 * @version $Id: TreeStackFrame.java,v 1.2 2002/02/25 21:06:01 cananian Exp $
21 duncan 1.1.2.1 */
22 duncan 1.1.2.1 final class TreeStackFrame extends StackFrame {
23 duncan 1.1.2.1 /** current location in the method */
24 duncan 1.1.2.1 Stm pc;
25 duncan 1.1.2.1 /** current mapping from <code>Temp</code>s to values. */
26 duncan 1.1.2.1 final Hashtable state = new Hashtable();
27 duncan 1.1.2.1 /** an object to stand for <code>null</code>. */
28 duncan 1.1.2.1 static final private Object Onull = new Object();
29 duncan 1.1.2.1
30 duncan 1.1.2.1 /** Class constructor. */
31 duncan 1.1.2.1 TreeStackFrame(Stm initial_pc) { this.pc = initial_pc; }
32 duncan 1.1.2.1
33 duncan 1.1.2.1 /** Replaces all instances of <code>obj1</code> in this stack frame
34 duncan 1.1.2.1 * with <code>obj2</code>. */
35 duncan 1.1.2.1 void replace(Object obj1, Object obj2) {
36 duncan 1.1.2.1 for (Enumeration e = state.keys(); e.hasMoreElements();) {
37 duncan 1.1.2.1 Object nextKey = e.nextElement();
38 duncan 1.1.2.1 if (state.get(nextKey).equals(obj1)) {
39 duncan 1.1.2.1 state.put(nextKey, obj2);
40 duncan 1.1.2.1 }
41 duncan 1.1.2.1 }
42 duncan 1.1.2.1 if (state.containsKey(obj1)) {
43 duncan 1.1.2.1 state.put(obj2, state.get(obj1));
44 duncan 1.1.2.1 state.remove(obj1);
45 duncan 1.1.2.1 }
46 duncan 1.1.2.1 }
47 duncan 1.1.2.1
48 duncan 1.1.2.1 void update(Temp t, Object value) {
49 duncan 1.1.2.4 if (DEBUG) db("Updating: " + t + " --> " + value);
50 duncan 1.1.2.1 state.put(t, (value==null)?Onull:value);
51 duncan 1.1.2.1 }
52 duncan 1.1.2.1
53 duncan 1.1.2.1 void update(Exp exp, Object value) {
54 duncan 1.1.2.4 if (DEBUG) db("Updating: " + exp + " --> " + value);
55 duncan 1.1.2.1 state.put(exp, (value==null)?Onull:value);
56 duncan 1.1.2.1 }
57 duncan 1.1.2.1
58 duncan 1.1.2.1 Object get(Temp t) {
59 duncan 1.1.2.1 Object o = state.get(t);
60 duncan 1.1.2.1 if (o==null) {
61 duncan 1.1.2.1 throw new Error("Use before def of "+t+" at " + getMethod() +
62 duncan 1.1.2.1 "("+ getSourceFile() +":"+ getLineNumber() +")"+
63 duncan 1.1.2.1 "::" + pc + "\n" + state.toString());
64 duncan 1.1.2.1 }
65 duncan 1.1.2.1 return (o==Onull)?Method.TREE_NULL:o;
66 duncan 1.1.2.1 }
67 duncan 1.1.2.1
68 duncan 1.1.2.1 Object get(Exp e) {
69 duncan 1.1.2.2 if (e instanceof TEMP) {
70 duncan 1.1.2.2 return get(((TEMP)e).temp);
71 duncan 1.1.2.2 }
72 duncan 1.1.2.2 else {
73 duncan 1.1.2.2 Object o = state.get(e);
74 duncan 1.1.2.2 if (o==null) {
75 duncan 1.1.2.2 throw new Error("Don't yet know the value of "+ e + " at "+
76 duncan 1.1.2.2 getMethod() + "("+getSourceFile() + ":"+
77 duncan 1.1.2.2 getLineNumber() + ")" + "::" + pc + "\n" +
78 duncan 1.1.2.2 state.toString());
79 duncan 1.1.2.2 }
80 duncan 1.1.2.2 return (o==Onull)?Method.TREE_NULL:o;
81 duncan 1.1.2.1 }
82 duncan 1.1.2.1 }
83 duncan 1.1.2.1
84 duncan 1.1.2.1 boolean isDefined(Exp e) {
85 duncan 1.1.2.1 return state.containsKey(e);
86 duncan 1.1.2.1 }
87 duncan 1.1.2.1
88 cananian 1.1.2.7 final HMethod getMethod() { return ((harpoon.IR.Tree.Code.TreeFactory)pc.getFactory()).getMethod(); }
89 duncan 1.1.2.1 final String getSourceFile() { return pc.getSourceFile(); }
90 duncan 1.1.2.1 final int getLineNumber() { return pc.getLineNumber(); }
91 duncan 1.1.2.1 }
92 duncan 1.1.2.1
93 duncan 1.1.2.1
94 duncan 1.1.2.1
95 duncan 1.1.2.1
96 duncan 1.1.2.1
97 duncan 1.1.2.1
98 duncan 1.1.2.1
99 duncan 1.1.2.1
100 cananian 1.2