1 cananian 1.1.2.1 // CONST.java, created Wed Jan 13 21:14:57 1999 by cananian
2 cananian 1.1.2.14 // Copyright (C) 1998 C. Scott Ananian <cananian@alumni.princeton.edu>
3 cananian 1.1.2.14 // Licensed under the terms of the GNU GPL; see COPYING for details.
4 cananian 1.1.2.1 package harpoon.IR.Tree;
5 cananian 1.1.2.1
6 cananian 1.1.2.5 import harpoon.ClassFile.HCodeElement;
7 cananian 1.1.2.19 import harpoon.ClassFile.HDataElement;
8 cananian 1.1.2.25 import harpoon.Temp.TempMap;
9 cananian 1.1.2.4 import harpoon.Util.Util;
10 cananian 1.1.2.4
11 cananian 1.1.2.1 /**
12 cananian 1.1.2.1 * <code>CONST</code> objects are expressions which stand for a constant
13 duncan 1.1.2.15 * value. <code>CONST</code>s should be used to represent numeric types
14 duncan 1.1.2.15 * only. The one notable exception is the constant <code>null</code>,
15 duncan 1.1.2.15 * which is represented by a <code>CONST</code> with <code>value == null</code>
16 duncan 1.1.2.15 * and <code>type == POINTER</code>.
17 cananian 1.1.2.1 *
18 cananian 1.1.2.1 * @author C. Scott Ananian <cananian@alumni.princeton.edu>, based on
19 cananian 1.1.2.1 * <i>Modern Compiler Implementation in Java</i> by Andrew Appel.
20 cananian 1.4 * @version $Id: CONST.java,v 1.4 2002/04/10 03:05:40 cananian Exp $
21 cananian 1.1.2.1 */
22 cananian 1.1.2.19 public class CONST extends Exp implements PreciselyTyped, HDataElement {
23 cananian 1.1.2.4 /** The constant value of this <code>CONST</code> expression. */
24 cananian 1.1.2.4 public final Number value;
25 cananian 1.1.2.4 /** The type of this <code>CONST</code> expression. */
26 cananian 1.1.2.4 public final int type;
27 cananian 1.1.2.4
28 cananian 1.1.2.20 // PreciselyTyped interface
29 cananian 1.1.2.20 public final boolean isSmall;
30 duncan 1.1.2.16 private int bitwidth = -1;
31 cananian 1.1.2.18 private boolean signed = true;
32 duncan 1.1.2.16
33 cananian 1.1.2.5 public CONST(TreeFactory tf, HCodeElement source, int ival) {
34 cananian 1.1.2.24 super(tf, source, 0);
35 cananian 1.1.2.20 this.type = INT; this.value = new Integer(ival); this.isSmall=false;
36 cananian 1.1.2.4 }
37 cananian 1.1.2.5 public CONST(TreeFactory tf, HCodeElement source, long lval) {
38 cananian 1.1.2.24 super(tf, source, 0);
39 cananian 1.1.2.20 this.type = LONG; this.value = new Long(lval); this.isSmall=false;
40 cananian 1.1.2.4 }
41 cananian 1.1.2.5 public CONST(TreeFactory tf, HCodeElement source, float fval) {
42 cananian 1.1.2.24 super(tf, source, 0);
43 cananian 1.1.2.20 this.type = FLOAT; this.value = new Float(fval); this.isSmall=false;
44 cananian 1.1.2.4 }
45 cananian 1.1.2.5 public CONST(TreeFactory tf, HCodeElement source, double dval) {
46 cananian 1.1.2.24 super(tf, source, 0);
47 cananian 1.1.2.20 this.type = DOUBLE; this.value = new Double(dval); this.isSmall=false;
48 cananian 1.1.2.4 }
49 duncan 1.1.2.15 /** Creates a <code>CONST</code> representing the constant
50 duncan 1.1.2.15 * <code>null</code>. */
51 duncan 1.1.2.15 public CONST(TreeFactory tf, HCodeElement source) {
52 cananian 1.1.2.24 super(tf, source, 0);
53 cananian 1.1.2.20 this.type = POINTER; this.value = null; this.isSmall=false;
54 duncan 1.1.2.12 }
55 duncan 1.1.2.15
56 duncan 1.1.2.16 /** Creates a CONST with a precisely defined type.
57 cananian 1.1.2.18 * For example, <code>CONST(tf, src, 8, true, 0xFF)</code> corresponds
58 cananian 1.1.2.18 * to the value <code>-1</code>, as a byte.
59 cananian 1.1.2.18 * <code>CONST(tf, src, 8, true, -1)</code> also corresponds
60 cananian 1.1.2.18 * to the value <code>-1</code> as a byte.
61 duncan 1.1.2.16 * @param bitwidth the width in bits of this <code>CONST</code>'s type.
62 duncan 1.1.2.16 * Fails unless <code>0 <= bitwidth < 32</code>.
63 duncan 1.1.2.16 * @param signed whether this <code>CONST</code> is signed
64 duncan 1.1.2.16 * @param val the value of this <code>CONST</code>.
65 duncan 1.1.2.16 * Note that only the lower <code>bitwidth</code> bits
66 duncan 1.1.2.16 * of this parameter will actually be used.
67 duncan 1.1.2.16 */
68 duncan 1.1.2.16 public CONST(TreeFactory tf, HCodeElement source,
69 duncan 1.1.2.16 int bitwidth, boolean signed, int val) {
70 cananian 1.1.2.24 super(tf, source, 0);
71 cananian 1.3.2.1 assert (0<=bitwidth)&&(bitwidth<32) : "Invalid bitwidth";
72 cananian 1.1.2.20 this.type = INT;
73 duncan 1.1.2.16 this.bitwidth = bitwidth;
74 duncan 1.1.2.16 this.signed = signed;
75 duncan 1.1.2.16 this.value = new Integer(val & ((~0) >> (32-bitwidth)));
76 cananian 1.1.2.20 this.isSmall = true;
77 duncan 1.1.2.16 }
78 duncan 1.1.2.16
79 duncan 1.1.2.8 private CONST(TreeFactory tf, HCodeElement source,
80 cananian 1.1.2.20 int type, Number value,
81 cananian 1.1.2.20 boolean isSmall, int bitwidth, boolean signed) {
82 cananian 1.1.2.24 super(tf, source, 0);
83 cananian 1.1.2.20 this.type = type; this.value = value; this.isSmall = isSmall;
84 duncan 1.1.2.17 this.bitwidth = bitwidth; this.signed = signed;
85 cananian 1.3.2.1 assert Type.isValid(type);
86 cananian 1.3.2.1 assert !isSmall || type==INT;
87 duncan 1.1.2.8 }
88 duncan 1.1.2.8
89 cananian 1.1.2.1 /** Return the constant value of this <code>CONST</code> expression. */
90 cananian 1.1.2.4 public Number value() { return value; }
91 duncan 1.1.2.10
92 duncan 1.1.2.10 public int kind() { return TreeKind.CONST; }
93 duncan 1.1.2.10
94 duncan 1.1.2.13 public Exp build(TreeFactory tf, ExpList kids) {
95 cananian 1.3.2.1 assert kids==null;
96 cananian 1.1.2.20 return new CONST(tf, this, type, value, isSmall, bitwidth, signed);
97 duncan 1.1.2.13 }
98 cananian 1.1.2.2
99 cananian 1.1.2.2 // Typed interface.
100 cananian 1.3.2.1 public int type() { assert Type.isValid(type); return type; }
101 cananian 1.1.2.4
102 duncan 1.1.2.16 // PreciselyTyped interface.
103 cananian 1.1.2.20 /** Returns true if this is a sub-integer expression. */
104 cananian 1.1.2.20 public boolean isSmall() { return isSmall; }
105 cananian 1.1.2.18 /** Returns the size of the expression, in bits.
106 cananian 1.1.2.20 * Only valid if the <code>isSmall()==true</code>. */
107 cananian 1.3.2.1 public int bitwidth() { assert type==INT&&isSmall; return bitwidth; }
108 cananian 1.1.2.18 /** Returns true if this is a signed expression, false otherwise.
109 cananian 1.1.2.20 * Only valid if the <code>isSmall()==true</code>. */
110 cananian 1.3.2.1 public boolean signed() { assert type==INT&&isSmall; return signed; }
111 duncan 1.1.2.16
112 duncan 1.1.2.3 /** Accept a visitor */
113 cananian 1.1.2.21 public void accept(TreeVisitor v) { v.visit(this); }
114 duncan 1.1.2.7
115 cananian 1.1.2.25 public Tree rename(TreeFactory tf, TempMap tm, CloneCallback cb) {
116 cananian 1.1.2.26 return cb.callback(this, new CONST(tf, this, type, value, isSmall, bitwidth, signed), tm);
117 duncan 1.1.2.7 }
118 andyb 1.1.2.9
119 andyb 1.1.2.9 public String toString() {
120 cananian 1.1.2.20 return "CONST<"+Type.toString(this)+">("+value+")";
121 andyb 1.1.2.9 }
122 cananian 1.2 }