1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
package dotty.tools.dotc
package typer
import java.lang.ArithmeticException
import ast._
import Trees._
import core._
import Types._
import Constants._
import Names._
import StdNames._
import Contexts._
object ConstFold {
import tpd._
/** If tree is a constant operation, replace with result. */
def apply(tree: Tree)(implicit ctx: Context): Tree = finish(tree) {
tree match {
case Apply(Select(xt, op), yt :: Nil) =>
xt.tpe.widenTermRefExpr match {
case ConstantType(x) =>
yt.tpe.widenTermRefExpr match {
case ConstantType(y) => foldBinop(op, x, y)
case _ => null
}
case _ => null
}
case Select(xt, op) =>
xt.tpe.widenTermRefExpr match {
case ConstantType(x) => foldUnop(op, x)
case _ => null
}
case _ => null
}
}
/** If tree is a constant value that can be converted to type `pt`, perform
* the conversion.
*/
def apply(tree: Tree, pt: Type)(implicit ctx: Context): Tree =
finish(apply(tree)) {
tree.tpe.widenTermRefExpr match {
case ConstantType(x) => x convertTo pt
case _ => null
}
}
private def finish(tree: Tree)(compX: => Constant)(implicit ctx: Context): Tree =
try {
val x = compX
if (x ne null) tree withType ConstantType(x)
else tree
} catch {
case _: ArithmeticException => tree // the code will crash at runtime,
// but that is better than the
// compiler itself crashing
}
private def foldUnop(op: Name, x: Constant): Constant = (op, x.tag) match {
case (nme.UNARY_!, BooleanTag) => Constant(!x.booleanValue)
case (nme.UNARY_~ , IntTag ) => Constant(~x.intValue)
case (nme.UNARY_~ , LongTag ) => Constant(~x.longValue)
case (nme.UNARY_+ , IntTag ) => Constant(x.intValue)
case (nme.UNARY_+ , LongTag ) => Constant(x.longValue)
case (nme.UNARY_+ , FloatTag ) => Constant(x.floatValue)
case (nme.UNARY_+ , DoubleTag ) => Constant(x.doubleValue)
case (nme.UNARY_- , IntTag ) => Constant(-x.intValue)
case (nme.UNARY_- , LongTag ) => Constant(-x.longValue)
case (nme.UNARY_- , FloatTag ) => Constant(-x.floatValue)
case (nme.UNARY_- , DoubleTag ) => Constant(-x.doubleValue)
case _ => null
}
/** These are local helpers to keep foldBinop from overly taxing the
* optimizer.
*/
private def foldBooleanOp(op: Name, x: Constant, y: Constant): Constant = op match {
case nme.ZOR => Constant(x.booleanValue | y.booleanValue)
case nme.OR => Constant(x.booleanValue | y.booleanValue)
case nme.XOR => Constant(x.booleanValue ^ y.booleanValue)
case nme.ZAND => Constant(x.booleanValue & y.booleanValue)
case nme.AND => Constant(x.booleanValue & y.booleanValue)
case nme.EQ => Constant(x.booleanValue == y.booleanValue)
case nme.NE => Constant(x.booleanValue != y.booleanValue)
case _ => null
}
private def foldSubrangeOp(op: Name, x: Constant, y: Constant): Constant = op match {
case nme.OR => Constant(x.intValue | y.intValue)
case nme.XOR => Constant(x.intValue ^ y.intValue)
case nme.AND => Constant(x.intValue & y.intValue)
case nme.LSL => Constant(x.intValue << y.intValue)
case nme.LSR => Constant(x.intValue >>> y.intValue)
case nme.ASR => Constant(x.intValue >> y.intValue)
case nme.EQ => Constant(x.intValue == y.intValue)
case nme.NE => Constant(x.intValue != y.intValue)
case nme.LT => Constant(x.intValue < y.intValue)
case nme.GT => Constant(x.intValue > y.intValue)
case nme.LE => Constant(x.intValue <= y.intValue)
case nme.GE => Constant(x.intValue >= y.intValue)
case nme.ADD => Constant(x.intValue + y.intValue)
case nme.SUB => Constant(x.intValue - y.intValue)
case nme.MUL => Constant(x.intValue * y.intValue)
case nme.DIV => Constant(x.intValue / y.intValue)
case nme.MOD => Constant(x.intValue % y.intValue)
case _ => null
}
private def foldLongOp(op: Name, x: Constant, y: Constant): Constant = op match {
case nme.OR => Constant(x.longValue | y.longValue)
case nme.XOR => Constant(x.longValue ^ y.longValue)
case nme.AND => Constant(x.longValue & y.longValue)
case nme.LSL => Constant(x.longValue << y.longValue)
case nme.LSR => Constant(x.longValue >>> y.longValue)
case nme.ASR => Constant(x.longValue >> y.longValue)
case nme.EQ => Constant(x.longValue == y.longValue)
case nme.NE => Constant(x.longValue != y.longValue)
case nme.LT => Constant(x.longValue < y.longValue)
case nme.GT => Constant(x.longValue > y.longValue)
case nme.LE => Constant(x.longValue <= y.longValue)
case nme.GE => Constant(x.longValue >= y.longValue)
case nme.ADD => Constant(x.longValue + y.longValue)
case nme.SUB => Constant(x.longValue - y.longValue)
case nme.MUL => Constant(x.longValue * y.longValue)
case nme.DIV => Constant(x.longValue / y.longValue)
case nme.MOD => Constant(x.longValue % y.longValue)
case _ => null
}
private def foldFloatOp(op: Name, x: Constant, y: Constant): Constant = op match {
case nme.EQ => Constant(x.floatValue == y.floatValue)
case nme.NE => Constant(x.floatValue != y.floatValue)
case nme.LT => Constant(x.floatValue < y.floatValue)
case nme.GT => Constant(x.floatValue > y.floatValue)
case nme.LE => Constant(x.floatValue <= y.floatValue)
case nme.GE => Constant(x.floatValue >= y.floatValue)
case nme.ADD => Constant(x.floatValue + y.floatValue)
case nme.SUB => Constant(x.floatValue - y.floatValue)
case nme.MUL => Constant(x.floatValue * y.floatValue)
case nme.DIV => Constant(x.floatValue / y.floatValue)
case nme.MOD => Constant(x.floatValue % y.floatValue)
case _ => null
}
private def foldDoubleOp(op: Name, x: Constant, y: Constant): Constant = op match {
case nme.EQ => Constant(x.doubleValue == y.doubleValue)
case nme.NE => Constant(x.doubleValue != y.doubleValue)
case nme.LT => Constant(x.doubleValue < y.doubleValue)
case nme.GT => Constant(x.doubleValue > y.doubleValue)
case nme.LE => Constant(x.doubleValue <= y.doubleValue)
case nme.GE => Constant(x.doubleValue >= y.doubleValue)
case nme.ADD => Constant(x.doubleValue + y.doubleValue)
case nme.SUB => Constant(x.doubleValue - y.doubleValue)
case nme.MUL => Constant(x.doubleValue * y.doubleValue)
case nme.DIV => Constant(x.doubleValue / y.doubleValue)
case nme.MOD => Constant(x.doubleValue % y.doubleValue)
case _ => null
}
private def foldBinop(op: Name, x: Constant, y: Constant): Constant = {
val optag =
if (x.tag == y.tag) x.tag
else if (x.isNumeric && y.isNumeric) math.max(x.tag, y.tag)
else NoTag
try optag match {
case BooleanTag => foldBooleanOp(op, x, y)
case ByteTag | ShortTag | CharTag | IntTag => foldSubrangeOp(op, x, y)
case LongTag => foldLongOp(op, x, y)
case FloatTag => foldFloatOp(op, x, y)
case DoubleTag => foldDoubleOp(op, x, y)
case StringTag if op == nme.ADD => Constant(x.stringValue + y.stringValue)
case _ => null
}
catch {
case ex: ArithmeticException => null
}
}
}
|
