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27
28 package soot.jimple.toolkits.scalar;
29
30 import soot.util.*;
31 import soot.*;
32 import soot.jimple.*;
33 import java.io.*;
34 import java.util.*;
35
36
37 public class Evaluator {
38
39 public static boolean isValueConstantValued(Value op) {
40
41 if (op instanceof Constant)
42 return true;
43 else if ((op instanceof UnopExpr)) {
44 if (isValueConstantValued(((UnopExpr)op).getOp()))
45 return true;
46 }
47 else if (op instanceof BinopExpr)
48 {
49
50 if (op instanceof DivExpr || op instanceof RemExpr)
51 {
52 if (!isValueConstantValued(((BinopExpr)op).getOp1()) ||
53 !isValueConstantValued(((BinopExpr)op).getOp2()))
54 return false;
55
56 Value c1 = getConstantValueOf(((BinopExpr)op).getOp1());
57 Value c2 = getConstantValueOf(((BinopExpr)op).getOp2());
58
59
60 if (c2 instanceof IntConstant && ((IntConstant)c2).value == 0)
61 return false;
62
63 if (c2 instanceof LongConstant &&
64 ((LongConstant)c2).value == 0)
65 return false;
66 }
67
68 if (isValueConstantValued(((BinopExpr)op).getOp1()) &&
69 isValueConstantValued(((BinopExpr)op).getOp2()))
70 return true;
71 }
72 return false;
73 }
75
77 public static Value getConstantValueOf(Value op) {
78
79 if (!isValueConstantValued(op))
80 return null;
81
82 if (op instanceof Constant)
83 return op;
84 else if (op instanceof UnopExpr) {
85 Value c = getConstantValueOf(((UnopExpr)op).getOp());
86 if (op instanceof NegExpr)
87 return ((NumericConstant)c).negate();
88 }
89 else if (op instanceof BinopExpr) {
90 Value c1 = getConstantValueOf(((BinopExpr)op).getOp1());
91 Value c2 = getConstantValueOf(((BinopExpr)op).getOp2());
92 if (op instanceof AddExpr)
93 return ((NumericConstant)c1).add((NumericConstant)c2);
94 else if (op instanceof SubExpr)
95 return ((NumericConstant)c1).subtract((NumericConstant)c2);
96 else if (op instanceof MulExpr)
97 return ((NumericConstant)c1).multiply((NumericConstant)c2);
98 else if (op instanceof DivExpr)
100 return ((NumericConstant)c1).divide((NumericConstant)c2);
101 else if (op instanceof RemExpr)
102 return ((NumericConstant)c1).remainder((NumericConstant)c2);
103 else if (op instanceof EqExpr || op instanceof NeExpr)
104 {
105 if (c1 instanceof NumericConstant)
106 {
107 if (op instanceof EqExpr)
108 return ((NumericConstant)c1).equalEqual
109 ((NumericConstant)c2);
110 else if (op instanceof NeExpr)
111 return ((NumericConstant)c1).notEqual
112 ((NumericConstant)c2);
113 }
114 else if (c1 instanceof StringConstant)
115 {
116 boolean equality = ((StringConstant)c1).equals
117 ((StringConstant)c2);
118
119 boolean truth = (op instanceof EqExpr) ? equality :
120 !equality;
121
122 IntConstant beauty = IntConstant.v(truth ? 1 : 0);
124 return beauty;
125 }
126 else if (c1 instanceof NullConstant)
127 return IntConstant.v
128 (((NullConstant)c1).equals(c2) ? 1 : 0);
129 throw new RuntimeException 
130 ("constant neither numeric nor string");
131 }
132 else if (op instanceof GtExpr)
133 return ((NumericConstant)c1).greaterThan((NumericConstant)c2);
134 else if (op instanceof GeExpr)
135 return ((NumericConstant)c1).greaterThanOrEqual((NumericConstant)c2);
136 else if (op instanceof LtExpr)
137 return ((NumericConstant)c1).lessThan((NumericConstant)c2);
138 else if (op instanceof LeExpr)
139 return ((NumericConstant)c1).lessThanOrEqual((NumericConstant)c2);
140 else if (op instanceof AndExpr)
141 return ((ArithmeticConstant)c1).and((ArithmeticConstant)c2);
142 else if (op instanceof OrExpr)
143 return ((ArithmeticConstant)c1).or((ArithmeticConstant)c2);
144 else if (op instanceof XorExpr)
145 return ((ArithmeticConstant)c1).xor((ArithmeticConstant)c2);
146 else if (op instanceof ShlExpr)
147 return ((ArithmeticConstant)c1).shiftLeft((ArithmeticConstant)c2);
148 else if (op instanceof ShrExpr)
149 return ((ArithmeticConstant)c1).shiftRight((ArithmeticConstant)c2);
150 else if (op instanceof UshrExpr)
151 return ((ArithmeticConstant)c1).unsignedShiftRight((ArithmeticConstant)c2);
152 else if (op instanceof CmpExpr) {
153 if ((c1 instanceof LongConstant) &&
154 (c2 instanceof LongConstant))
155 return ((LongConstant)c1).cmp((LongConstant)c2);
156 else throw new IllegalArgumentException (
157 "CmpExpr: LongConstant(s) expected");
158 }
159 else if ((op instanceof CmpgExpr) || (op instanceof CmplExpr)) {
160 if ((c1 instanceof RealConstant) &&
161 (c2 instanceof RealConstant)) {
162
163 if(op instanceof CmpgExpr)
164 return ((RealConstant) c1).cmpg((RealConstant) c2);
165 else if(op instanceof CmplExpr)
166 return ((RealConstant) c1).cmpl((RealConstant) c2);
167
168 }
169 else throw new IllegalArgumentException (
170 "CmpExpr: RealConstant(s) expected");
171 }
172 else
173 throw new RuntimeException ("unknown binop: " + op);
174 }
175
176 throw new RuntimeException ("couldn't getConstantValueOf of: " + op);
177 }
179 }
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