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
|
/*
* 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 jdk.nashorn.internal.codegen.types.Type;
import jdk.nashorn.internal.runtime.Debug;
/**
* Abstraction for labels, separating a label from the underlying
* byte code emitter. Also augmenting label with e.g. a name
* for easier debugging and reading code
*
* see -Dnashorn.codegen.debug, --log=codegen
*/
public final class Label {
//byte code generation evaluation type stack for consistency check
//and correct opcode selection. one per label as a label may be a
//join point
static final class Stack {
Type[] data = new Type[8];
int sp = 0;
Stack() {
}
private Stack(final Type[] type, final int sp) {
this();
this.data = new Type[type.length];
this.sp = sp;
for (int i = 0; i < sp; i++) {
data[i] = type[i];
}
}
boolean isEmpty() {
return sp == 0;
}
int size() {
return sp;
}
boolean isEquivalentTo(final Stack other) {
if (sp != other.sp) {
return false;
}
for (int i = 0; i < sp; i++) {
if (!data[i].isEquivalentTo(other.data[i])) {
return false;
}
}
return true;
}
void clear() {
sp = 0;
}
void push(final Type type) {
if (data.length == sp) {
final Type[] newData = new Type[sp * 2];
for (int i = 0; i < sp; i++) {
newData[i] = data[i];
}
data = newData;
}
data[sp++] = type;
}
Type peek() {
return peek(0);
}
Type peek(final int n) {
int pos = sp - 1 - n;
return pos < 0 ? null : data[pos];
}
Type pop() {
return data[--sp];
}
Stack copy() {
return new Stack(data, sp);
}
}
/** Name of this label */
private final String name;
/** Type stack at this label */
private Label.Stack stack;
/** ASM representation of this label */
private jdk.internal.org.objectweb.asm.Label label;
/**
* Constructor
*
* @param name name of this label
*/
public Label(final String name) {
super();
this.name = name;
}
/**
* Copy constructor
*
* @param label a label to clone
*/
public Label(final Label label) {
super();
this.name = label.name;
}
jdk.internal.org.objectweb.asm.Label getLabel() {
if (this.label == null) {
this.label = new jdk.internal.org.objectweb.asm.Label();
}
return label;
}
Label.Stack getStack() {
return stack;
}
void setStack(final Label.Stack stack) {
this.stack = stack;
}
@Override
public String toString() {
return name + '_' + Debug.id(this);
}
}
|
