1 cananian 1.1.2.1 // SWITCH.java, created Wed Aug 26 20:45:24 1998 by cananian
2 cananian 1.1.2.1 // Copyright (C) 1998 C. Scott Ananian <cananian@alumni.princeton.edu>
3 cananian 1.1.2.1 // Licensed under the terms of the GNU GPL; see COPYING for details.
4 cananian 1.1.2.1 package harpoon.IR.Quads;
5 cananian 1.1.2.1
6 cananian 1.1.2.1 import harpoon.ClassFile.HClass;
7 cananian 1.1.2.1 import harpoon.ClassFile.HCodeElement;
8 cananian 1.1.2.1 import harpoon.Temp.Temp;
9 cananian 1.1.2.1 import harpoon.Temp.TempMap;
10 cananian 1.1.2.1 import harpoon.Util.Util;
11 cananian 1.1.2.1
12 cananian 1.1.2.1 /**
13 cananian 1.1.2.3 * <code>TYPESWITCH</code> represents a multiple-way branch dependent on
14 cananian 1.1.2.5 * the class type of the argument. It may optionally omit the default
15 cananian 1.1.2.5 * case, in which case it is read as an assertion on the type of the
16 cananian 1.1.2.5 * argument, in addition to its usual semantics.
17 cananian 1.1.2.1 *
18 cananian 1.1.2.1 * @author C. Scott Ananian <cananian@alumni.princeton.edu>
19 cananian 1.5 * @version $Id: TYPESWITCH.java,v 1.5 2002/04/11 04:00:35 cananian Exp $
20 cananian 1.1.2.1 */
21 cananian 1.1.2.1 public class TYPESWITCH extends SIGMA {
22 cananian 1.1.2.3 /** The discriminant, of <code>Object</code> type, whose class is
23 cananian 1.1.2.3 * compared against each class type in <code>keys[]</code>.*/
24 cananian 1.1.2.1 protected Temp index;
25 cananian 1.1.2.3 /** Class type keys for typeswitch cases. <p>
26 cananian 1.1.2.1 * <code>next(n)</code> is the jump target corresponding to
27 cananian 1.1.2.1 * <code>keys[n]</code> for <code>0 <= n < keys.length</code>. <p>
28 cananian 1.1.2.1 * <code>next(keys.length)</code> is the default target. */
29 cananian 1.1.2.1 protected HClass keys[];
30 cananian 1.1.2.5 /** True if this <code>TYPESWITCH</code> has a default case. */
31 cananian 1.1.2.5 protected boolean hasDefault;
32 cananian 1.1.2.1
33 cananian 1.1.2.1 /** Creates a <code>TYPESWITCH</code> operation. <p>
34 cananian 1.1.2.1 * <code>next[n]</code> is the jump target corresponding to
35 cananian 1.1.2.1 * <code>keys[n]</code> for <code>0 <= n < keys.length</code>. <p>
36 cananian 1.1.2.1 * <code>next[keys.length]</code> is the default target.<p>
37 cananian 1.1.2.1 * Order among the keys is important; the destination corresponds
38 cananian 1.1.2.1 * to the *first* class type matching the argument.
39 cananian 1.1.2.1 * We differ from the modula-3
40 cananian 1.1.2.1 * <a href="http://research.compaq.com/SRC/m3defn/html/typecase.html">
41 cananian 1.1.2.1 * TYPECASE</a> statement by disallowing <code>null</code> as a valid
42 cananian 1.1.2.2 * key value. The discriminant is also not permitted to be
43 cananian 1.1.2.2 * <code>null</code> (except in quad-with-try form, in which case
44 cananian 1.1.2.2 * a <code>null</code> discriminant causes the default branch to
45 cananian 1.1.2.5 * be taken). If <code>withDefault</code> is <code>true</code>,
46 cananian 1.1.2.5 * a default edge will be taken if none of the keys match the type
47 cananian 1.1.2.5 * of the argument; otherwise we assert that at least one key will
48 cananian 1.1.2.5 * always match the argument.
49 cananian 1.1.2.1 * @param index
50 cananian 1.1.2.1 * the discriminant.
51 cananian 1.1.2.1 * @param keys
52 cananian 1.1.2.1 * class type keys for switch cases.
53 cananian 1.1.2.1 * @param dst
54 cananian 1.1.2.1 * sigma function left-hand sides.
55 cananian 1.1.2.1 * @param src
56 cananian 1.1.2.1 * sigma function arguments.
57 cananian 1.1.2.5 * @param hasDefault
58 cananian 1.1.2.5 * <code>true</code> if this <code>TYPESWITCH</code> should
59 cananian 1.1.2.5 * have a default case.
60 cananian 1.1.2.1 */
61 cananian 1.1.2.1 public TYPESWITCH(QuadFactory qf, HCodeElement source,
62 cananian 1.1.2.1 Temp index, HClass keys[],
63 cananian 1.1.2.5 Temp dst[][], Temp src[], boolean hasDefault) {
64 cananian 1.1.2.5 super(qf, source, dst, src, keys.length+(hasDefault?1:0));
65 cananian 1.1.2.1 this.index = index;
66 cananian 1.1.2.1 this.keys = keys;
67 cananian 1.1.2.5 this.hasDefault = hasDefault;
68 cananian 1.1.2.4 // VERIFY legality of TYPESWITCH.
69 cananian 1.3.2.1 assert index!=null && keys!=null;
70 cananian 1.3.2.1 assert keys.length+(hasDefault?1:0)==arity();
71 cananian 1.1.2.1 for (int i=0; i<keys.length; i++)
72 cananian 1.3.2.1 assert keys[i]!=null;
73 cananian 1.1.2.5 // can't have no keys *and* no default.
74 cananian 1.3.2.1 assert arity()>0;
75 cananian 1.1.2.1 }
76 cananian 1.1.2.3 /** Creates a typeswitch with arity defined by the keys array. */
77 cananian 1.1.2.1 public TYPESWITCH(QuadFactory qf, HCodeElement source,
78 cananian 1.1.2.5 Temp index, HClass keys[], Temp src[],
79 cananian 1.1.2.5 boolean hasDefault) {
80 cananian 1.1.2.5 this(qf,source, index, keys,
81 cananian 1.1.2.5 new Temp[src.length][keys.length+1], src, hasDefault);
82 cananian 1.1.2.1 }
83 cananian 1.1.2.1 /** Returns the <code>Temp</code> holding the discriminant. */
84 cananian 1.1.2.1 public Temp index() { return index; }
85 cananian 1.1.2.1 /** Returns the array of class type keys for the typeswitch cases. */
86 cananian 1.1.2.1 public HClass[] keys() { return (HClass[]) keys.clone(); }
87 cananian 1.1.2.1 /** Returns a given element in the <code>keys</code> array. */
88 cananian 1.1.2.1 public HClass keys(int i) { return keys[i]; }
89 cananian 1.1.2.1 /** Returns the length of the <code>keys</code> array. */
90 cananian 1.1.2.1 public int keysLength() { return keys.length; }
91 cananian 1.1.2.5 /** Returns <code>true</code> if this <code>TYPESWITCH</code> has a
92 cananian 1.1.2.5 * default case. */
93 cananian 1.1.2.5 public boolean hasDefault() { return hasDefault; }
94 cananian 1.1.2.1
95 cananian 1.1.2.1 /** Returns the <code>Temp</code> used by this quad.
96 cananian 1.1.2.1 * @return the <code>index</code> field. */
97 cananian 1.1.2.1 public Temp[] use() {
98 cananian 1.1.2.1 Temp[] u = super.use();
99 cananian 1.1.2.1 Temp[] r = new Temp[u.length+1];
100 cananian 1.1.2.1 System.arraycopy(u, 0, r, 0, u.length);
101 cananian 1.1.2.1 // add 'index' to end of use array.
102 cananian 1.1.2.1 r[u.length] = index;
103 cananian 1.1.2.1 return r;
104 cananian 1.1.2.1 }
105 cananian 1.1.2.1
106 cananian 1.1.2.1 public int kind() { return QuadKind.TYPESWITCH; }
107 cananian 1.1.2.1
108 cananian 1.1.2.1 public Quad rename(QuadFactory qqf, TempMap defMap, TempMap useMap) {
109 cananian 1.1.2.1 return new TYPESWITCH(qqf, this, map(useMap,index),
110 cananian 1.1.2.1 (HClass[])keys.clone(),
111 cananian 1.1.2.5 map(defMap,dst), map(useMap,src), hasDefault);
112 cananian 1.1.2.1 }
113 cananian 1.1.2.1 /** Rename all used variables in this Quad according to a mapping.
114 cananian 1.1.2.1 * @deprecated does not preserve immutability. */
115 cananian 1.1.2.1 void renameUses(TempMap tm) {
116 cananian 1.1.2.1 super.renameUses(tm);
117 cananian 1.1.2.1 index = tm.tempMap(index);
118 cananian 1.1.2.1 }
119 cananian 1.1.2.1 /** Rename all defined variables in this Quad according to a mapping.
120 cananian 1.1.2.1 * @deprecated does not preserve immutability. */
121 cananian 1.1.2.1 void renameDefs(TempMap tm) {
122 cananian 1.1.2.1 super.renameDefs(tm);
123 cananian 1.1.2.1 }
124 cananian 1.1.2.1
125 cananian 1.1.2.1 public void accept(QuadVisitor v) { v.visit(this); }
126 cananian 1.5 public <T> T accept(QuadValueVisitor<T> v) { return v.visit(this); }
127 cananian 1.1.2.1
128 cananian 1.1.2.1 /** Returns human-readable representation of this quad. */
129 cananian 1.1.2.1 public String toString() {
130 cananian 1.1.2.1 StringBuffer sb = new StringBuffer("TYPESWITCH "+index+": ");
131 cananian 1.1.2.1 for (int i=0; i<keys.length; i++)
132 cananian 1.1.2.1 sb.append("case "+keys[i]+"; ");
133 cananian 1.1.2.5 if (!hasDefault) sb.append("no ");
134 cananian 1.1.2.1 sb.append("default");
135 cananian 1.1.2.1 sb.append(" / "); sb.append(super.toString());
136 cananian 1.1.2.1 return sb.toString();
137 cananian 1.1.2.1 }
138 cananian 1.2 }