KotlinDefaultArgumentsFilter.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.Set;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.tree.AbstractInsnNode;
import org.objectweb.asm.tree.JumpInsnNode;
import org.objectweb.asm.tree.LdcInsnNode;
import org.objectweb.asm.tree.MethodNode;
import org.objectweb.asm.tree.VarInsnNode;
/**
* Filters branches that Kotlin compiler generates for default arguments.
*
* For methods and constructors with default arguments Kotlin compiler generates
* synthetic method with suffix "$default" or a synthetic constructor with last
* argument "kotlin.jvm.internal.DefaultConstructorMarker" respectively. And in
* this synthetic method for each default argument Kotlin compiler generates
* following bytecode to determine if it should be used or not:
*
* <pre>
* ILOAD maskVar
* ICONST_x, BIPUSH, SIPUSH, LDC or LDC_W
* IAND
* IFEQ label
* default argument
* label:
* </pre>
*
* If original method has <code>X</code> arguments, then in synthetic method
* <code>maskVar</code> is one of arguments from <code>X+1</code> to
* <code>X+1+(X/32)</code>.
*
* At least one of such arguments is not zero - invocation without default
* arguments uses original non synthetic method.
*
* This filter marks <code>IFEQ</code> instructions as ignored.
*/
public final class KotlinDefaultArgumentsFilter implements IFilter {
static boolean isDefaultArgumentsMethod(final MethodNode methodNode) {
return methodNode.name.endsWith("$default");
}
static boolean isDefaultArgumentsConstructor(final MethodNode methodNode) {
if (!"<init>".equals(methodNode.name)) {
return false;
}
final Type[] argumentTypes = Type.getMethodType(methodNode.desc)
.getArgumentTypes();
if (argumentTypes.length < 2) {
return false;
}
return "kotlin.jvm.internal.DefaultConstructorMarker"
.equals(argumentTypes[argumentTypes.length - 1].getClassName());
}
public void filter(final MethodNode methodNode,
final IFilterContext context, final IFilterOutput output) {
if ((methodNode.access & Opcodes.ACC_SYNTHETIC) == 0) {
return;
}
if (!KotlinGeneratedFilter.isKotlinClass(context)) {
return;
}
if (isDefaultArgumentsMethod(methodNode)) {
new Matcher().match(methodNode, output, false);
} else if (isDefaultArgumentsConstructor(methodNode)) {
new Matcher().match(methodNode, output, true);
}
}
private static class Matcher extends AbstractMatcher {
public void match(final MethodNode methodNode,
final IFilterOutput output, final boolean constructor) {
cursor = skipNonOpcodes(methodNode.instructions.getFirst());
nextIs(Opcodes.IFNULL);
nextIsType(Opcodes.NEW, "java/lang/UnsupportedOperationException");
nextIs(Opcodes.DUP);
nextIs(Opcodes.LDC);
if (cursor == null
|| !(((LdcInsnNode) cursor).cst instanceof String)
|| !(((String) ((LdcInsnNode) cursor).cst).startsWith(
"Super calls with default arguments not supported in this target"))) {
cursor = null;
}
nextIsInvoke(Opcodes.INVOKESPECIAL,
"java/lang/UnsupportedOperationException", "<init>",
"(Ljava/lang/String;)V");
nextIs(Opcodes.ATHROW);
if (cursor != null) {
output.ignore(methodNode.instructions.getFirst(), cursor);
next();
} else {
cursor = skipNonOpcodes(methodNode.instructions.getFirst());
}
final Set<AbstractInsnNode> ignore = new HashSet<AbstractInsnNode>();
final int maskVar = maskVar(methodNode.desc, constructor);
while (true) {
if (cursor.getOpcode() != Opcodes.ILOAD) {
break;
}
if (((VarInsnNode) cursor).var != maskVar) {
break;
}
next();
nextIs(Opcodes.IAND);
nextIs(Opcodes.IFEQ);
if (cursor == null) {
return;
}
ignore.add(cursor);
cursor = ((JumpInsnNode) cursor).label;
skipNonOpcodes();
}
for (AbstractInsnNode i : ignore) {
output.ignore(i, i);
}
}
private static int maskVar(final String desc,
final boolean constructor) {
final Type[] argumentTypes = Type.getMethodType(desc)
.getArgumentTypes();
int slot = 0;
if (constructor) {
// one slot for reference to current object
slot++;
}
final int firstMaskArgument = argumentTypes.length - 1
- computeNumberOfMaskArguments(argumentTypes.length);
for (int i = 0; i < firstMaskArgument; i++) {
slot += argumentTypes[i].getSize();
}
return slot;
}
}
/**
* @param arguments
* number of arguments of synthetic method
* @return number of arguments holding mask
*/
static int computeNumberOfMaskArguments(final int arguments) {
return (arguments - 2) / 33 + 1;
}
}