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
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
|
/*******************************************************************************
* Copyright (c) 2009, 2021 Mountainminds GmbH & Co. KG and Contributors
* This program and the accompanying materials are made available under
* the terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0
*
* SPDX-License-Identifier: EPL-2.0
*
* Contributors:
* Marc R. Hoffmann - initial API and implementation
*
*******************************************************************************/
package org.jacoco.core.internal.flow;
import org.jacoco.core.internal.instr.InstrSupport;
import org.objectweb.asm.Handle;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.tree.MethodNode;
/**
* Method visitor to collect flow related information about the {@link Label}s
* within a class. It calculates the properties "multitarget" and "successor"
* that can afterwards be obtained via {@link LabelInfo}.
*/
public final class LabelFlowAnalyzer extends MethodVisitor {
/**
* Marks all labels of the method with control flow information.
*
* @param method
* Method to mark labels
*/
public static void markLabels(final MethodNode method) {
// We do not use the accept() method as ASM resets labels after every
// call to accept()
final MethodVisitor lfa = new LabelFlowAnalyzer();
for (int i = method.tryCatchBlocks.size(); --i >= 0;) {
method.tryCatchBlocks.get(i).accept(lfa);
}
method.instructions.accept(lfa);
}
/**
* <code>true</code> if the current instruction is a potential successor of
* the previous instruction. Accessible for testing.
*/
boolean successor = false;
/**
* <code>true</code> for the very first instruction only. Accessible for
* testing.
*/
boolean first = true;
/**
* Label instance of the last line start.
*/
Label lineStart = null;
/**
* Create new instance.
*/
public LabelFlowAnalyzer() {
super(InstrSupport.ASM_API_VERSION);
}
@Override
public void visitTryCatchBlock(final Label start, final Label end,
final Label handler, final String type) {
// Enforce probe at the beginning of the block. Assuming the start of
// the block already is successor of some other code, adding a target
// makes the start a multitarget. However, if the start of the block
// also is the start of the method, no probe will be added.
LabelInfo.setTarget(start);
// Mark exception handler as possible target of the block
LabelInfo.setTarget(handler);
}
@Override
public void visitJumpInsn(final int opcode, final Label label) {
LabelInfo.setTarget(label);
if (opcode == Opcodes.JSR) {
throw new AssertionError("Subroutines not supported.");
}
successor = opcode != Opcodes.GOTO;
first = false;
}
@Override
public void visitLabel(final Label label) {
if (first) {
LabelInfo.setTarget(label);
}
if (successor) {
LabelInfo.setSuccessor(label);
}
}
@Override
public void visitLineNumber(final int line, final Label start) {
lineStart = start;
}
@Override
public void visitTableSwitchInsn(final int min, final int max,
final Label dflt, final Label... labels) {
visitSwitchInsn(dflt, labels);
}
@Override
public void visitLookupSwitchInsn(final Label dflt, final int[] keys,
final Label[] labels) {
visitSwitchInsn(dflt, labels);
}
private void visitSwitchInsn(final Label dflt, final Label[] labels) {
LabelInfo.resetDone(dflt);
LabelInfo.resetDone(labels);
setTargetIfNotDone(dflt);
for (final Label l : labels) {
setTargetIfNotDone(l);
}
successor = false;
first = false;
}
private static void setTargetIfNotDone(final Label label) {
if (!LabelInfo.isDone(label)) {
LabelInfo.setTarget(label);
LabelInfo.setDone(label);
}
}
@Override
public void visitInsn(final int opcode) {
switch (opcode) {
case Opcodes.RET:
throw new AssertionError("Subroutines not supported.");
case Opcodes.IRETURN:
case Opcodes.LRETURN:
case Opcodes.FRETURN:
case Opcodes.DRETURN:
case Opcodes.ARETURN:
case Opcodes.RETURN:
case Opcodes.ATHROW:
successor = false;
break;
default:
successor = true;
break;
}
first = false;
}
@Override
public void visitIntInsn(final int opcode, final int operand) {
successor = true;
first = false;
}
@Override
public void visitVarInsn(final int opcode, final int var) {
successor = true;
first = false;
}
@Override
public void visitTypeInsn(final int opcode, final String type) {
successor = true;
first = false;
}
@Override
public void visitFieldInsn(final int opcode, final String owner,
final String name, final String desc) {
successor = true;
first = false;
}
@Override
public void visitMethodInsn(final int opcode, final String owner,
final String name, final String desc, final boolean itf) {
successor = true;
first = false;
markMethodInvocationLine();
}
@Override
public void visitInvokeDynamicInsn(final String name, final String desc,
final Handle bsm, final Object... bsmArgs) {
successor = true;
first = false;
markMethodInvocationLine();
}
private void markMethodInvocationLine() {
if (lineStart != null) {
LabelInfo.setMethodInvocationLine(lineStart);
}
}
@Override
public void visitLdcInsn(final Object cst) {
successor = true;
first = false;
}
@Override
public void visitIincInsn(final int var, final int increment) {
successor = true;
first = false;
}
@Override
public void visitMultiANewArrayInsn(final String desc, final int dims) {
successor = true;
first = false;
}
}
|
