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
|
/*
* Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package jdk.nashorn.internal.codegen;
import static jdk.nashorn.internal.codegen.Condition.EQ;
import static jdk.nashorn.internal.codegen.Condition.GE;
import static jdk.nashorn.internal.codegen.Condition.GT;
import static jdk.nashorn.internal.codegen.Condition.LE;
import static jdk.nashorn.internal.codegen.Condition.LT;
import static jdk.nashorn.internal.codegen.Condition.NE;
import jdk.nashorn.internal.codegen.types.Type;
import jdk.nashorn.internal.ir.BinaryNode;
import jdk.nashorn.internal.ir.Expression;
import jdk.nashorn.internal.ir.TernaryNode;
import jdk.nashorn.internal.ir.UnaryNode;
/**
* Branch optimizer for CodeGenerator. Given a jump condition this helper
* class attempts to simplify the control flow
*/
final class BranchOptimizer {
private final CodeGenerator codegen;
private final MethodEmitter method;
BranchOptimizer(final CodeGenerator codegen, final MethodEmitter method) {
this.codegen = codegen;
this.method = method;
}
void execute(final Expression node, final Label label, final boolean state) {
branchOptimizer(node, label, state);
}
private void branchOptimizer(final UnaryNode unaryNode, final Label label, final boolean state) {
final Expression rhs = unaryNode.rhs();
switch (unaryNode.tokenType()) {
case NOT:
branchOptimizer(rhs, label, !state);
return;
default:
if (unaryNode.getType().isBoolean()) {
branchOptimizer(rhs, label, state);
return;
}
break;
}
// convert to boolean
codegen.load(unaryNode, Type.BOOLEAN);
if (state) {
method.ifne(label);
} else {
method.ifeq(label);
}
}
private void branchOptimizer(final BinaryNode binaryNode, final Label label, final boolean state) {
final Expression lhs = binaryNode.lhs();
final Expression rhs = binaryNode.rhs();
switch (binaryNode.tokenType()) {
case AND:
if (state) {
final Label skip = new Label("skip");
branchOptimizer(lhs, skip, false);
branchOptimizer(rhs, label, true);
method.label(skip);
} else {
branchOptimizer(lhs, label, false);
branchOptimizer(rhs, label, false);
}
return;
case OR:
if (state) {
branchOptimizer(lhs, label, true);
branchOptimizer(rhs, label, true);
} else {
final Label skip = new Label("skip");
branchOptimizer(lhs, skip, true);
branchOptimizer(rhs, label, false);
method.label(skip);
}
return;
case EQ:
case EQ_STRICT:
codegen.loadBinaryOperands(lhs, rhs, Type.widest(lhs.getType(), rhs.getType()));
method.conditionalJump(state ? EQ : NE, true, label);
return;
case NE:
case NE_STRICT:
codegen.loadBinaryOperands(lhs, rhs, Type.widest(lhs.getType(), rhs.getType()));
method.conditionalJump(state ? NE : EQ, true, label);
return;
case GE:
codegen.loadBinaryOperands(lhs, rhs, Type.widest(lhs.getType(), rhs.getType()));
method.conditionalJump(state ? GE : LT, !state, label);
return;
case GT:
codegen.loadBinaryOperands(lhs, rhs, Type.widest(lhs.getType(), rhs.getType()));
method.conditionalJump(state ? GT : LE, !state, label);
return;
case LE:
codegen.loadBinaryOperands(lhs, rhs, Type.widest(lhs.getType(), rhs.getType()));
method.conditionalJump(state ? LE : GT, state, label);
return;
case LT:
codegen.loadBinaryOperands(lhs, rhs, Type.widest(lhs.getType(), rhs.getType()));
method.conditionalJump(state ? LT : GE, state, label);
return;
default:
break;
}
codegen.load(binaryNode, Type.BOOLEAN);
if (state) {
method.ifne(label);
} else {
method.ifeq(label);
}
}
private void branchOptimizer(final Expression node, final Label label, final boolean state) {
if (!(node instanceof TernaryNode)) {
if (node instanceof BinaryNode) {
branchOptimizer((BinaryNode)node, label, state);
return;
}
if (node instanceof UnaryNode) {
branchOptimizer((UnaryNode)node, label, state);
return;
}
}
codegen.load(node, Type.BOOLEAN);
if (state) {
method.ifne(label);
} else {
method.ifeq(label);
}
}
}
|
