ExhaustiveSwitchFilter.java
/*******************************************************************************
* Copyright (c) 2009, 2024 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:
* Evgeny Mandrikov - initial API and implementation
*
*******************************************************************************/
package org.jacoco.core.internal.analysis.filter;
import java.util.HashSet;
import java.util.List;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.tree.AbstractInsnNode;
import org.objectweb.asm.tree.LabelNode;
import org.objectweb.asm.tree.LineNumberNode;
import org.objectweb.asm.tree.LookupSwitchInsnNode;
import org.objectweb.asm.tree.MethodNode;
import org.objectweb.asm.tree.TableSwitchInsnNode;
import org.objectweb.asm.tree.TypeInsnNode;
/**
* Filters default branch generated by compilers for exhaustive switch
* expressions.
*/
final class ExhaustiveSwitchFilter implements IFilter {
public void filter(final MethodNode methodNode,
final IFilterContext context, final IFilterOutput output) {
final Matcher matcher = new Matcher();
int line = -1;
for (final AbstractInsnNode i : methodNode.instructions) {
if (i.getType() == AbstractInsnNode.LINE) {
line = ((LineNumberNode) i).line;
}
matcher.match(i, line, output);
}
}
private static class Matcher extends AbstractMatcher {
public void match(final AbstractInsnNode start, final int line,
final IFilterOutput output) {
final LabelNode dflt;
final List<LabelNode> labels;
if (start.getOpcode() == Opcodes.LOOKUPSWITCH) {
dflt = ((LookupSwitchInsnNode) start).dflt;
labels = ((LookupSwitchInsnNode) start).labels;
} else if (start.getOpcode() == Opcodes.TABLESWITCH) {
dflt = ((TableSwitchInsnNode) start).dflt;
labels = ((TableSwitchInsnNode) start).labels;
} else {
return;
}
cursor = skipToLineNumberOrInstruction(dflt);
if (cursor == null) {
return;
}
if (cursor.getType() == AbstractInsnNode.LINE) {
if (line != ((LineNumberNode) cursor).line) {
return;
}
cursor = skipNonOpcodes(cursor);
}
if (cursor == null || cursor.getOpcode() != Opcodes.NEW) {
return;
}
if ("java/lang/MatchException"
.equals(((TypeInsnNode) cursor).desc)) {
// since Java 21
nextIs(Opcodes.DUP);
nextIs(Opcodes.ACONST_NULL);
nextIs(Opcodes.ACONST_NULL);
nextIsInvoke(Opcodes.INVOKESPECIAL, "java/lang/MatchException",
"<init>", "(Ljava/lang/String;Ljava/lang/Throwable;)V");
} else if ("java/lang/IncompatibleClassChangeError"
.equals(((TypeInsnNode) cursor).desc)) {
// prior to Java 21
nextIs(Opcodes.DUP);
nextIsInvoke(Opcodes.INVOKESPECIAL,
"java/lang/IncompatibleClassChangeError", "<init>",
"()V");
} else {
return;
}
nextIs(Opcodes.ATHROW);
if (cursor == null) {
return;
}
output.ignore(dflt, cursor);
final HashSet<AbstractInsnNode> replacements = new HashSet<AbstractInsnNode>();
for (final AbstractInsnNode label : labels) {
replacements.add(skipNonOpcodes(label));
}
output.replaceBranches(start, replacements);
}
private static AbstractInsnNode skipToLineNumberOrInstruction(
AbstractInsnNode cursor) {
while (cursor != null && (cursor.getType() == AbstractInsnNode.FRAME
|| cursor.getType() == AbstractInsnNode.LABEL)) {
cursor = cursor.getNext();
}
return cursor;
}
}
}