Report code coverage correctly for Kotlin methods with default arguments (#774)

5 files changed, 124 insertions, 7 deletions

diff --git a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/AbstractMatcher.java b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/AbstractMatcher.java
index 9b01e777..a4dd6208 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/AbstractMatcher.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/AbstractMatcher.java
@@ -154,7 +154,11 @@ abstract class AbstractMatcher {
 		skipNonOpcodes();
 	}
 
-	private void skipNonOpcodes() {
+	/**
+	 * Moves {@link #cursor} through {@link AbstractInsnNode#FRAME},
+	 * {@link AbstractInsnNode#LABEL}, {@link AbstractInsnNode#LINE}.
+	 */
+	final void skipNonOpcodes() {
 		while (cursor != null && (cursor.getType() == AbstractInsnNode.FRAME
 				|| cursor.getType() == AbstractInsnNode.LABEL
 				|| cursor.getType() == AbstractInsnNode.LINE)) {
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/Filters.java b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/Filters.java
index f6a7a1df..76b050f4 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/Filters.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/Filters.java
@@ -35,7 +35,8 @@ public final class Filters implements IFilter {
 			new EnumEmptyConstructorFilter(), new AnnotationGeneratedFilter(),
 			new KotlinGeneratedFilter(), new KotlinLateinitFilter(),
 			new KotlinWhenFilter(), new KotlinWhenStringFilter(),
-			new KotlinUnsafeCastOperatorFilter());
+			new KotlinUnsafeCastOperatorFilter(),
+			new KotlinDefaultArgumentsFilter());
 
 	private final IFilter[] filters;
 
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/KotlinDefaultArgumentsFilter.java b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/KotlinDefaultArgumentsFilter.java
new file mode 100644
index 00000000..8c2bdeba
--- /dev/null
+++ b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/KotlinDefaultArgumentsFilter.java
@@ -0,0 +1,97 @@
+/*******************************************************************************
+ * Copyright (c) 2009, 2018 Mountainminds GmbH & Co. KG and Contributors
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * 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.MethodNode;
+import org.objectweb.asm.tree.VarInsnNode;
+
+/**
+ * Filters branches that Kotlin compiler generates for default arguments.
+ * 
+ * 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>
+ * 
+ * Where <code>maskVar</code> is penultimate argument of synthetic method with
+ * suffix "$default". And its value can't be zero - invocation with all
+ * arguments uses original non synthetic method, thus <code>IFEQ</code>
+ * instructions should be ignored.
+ */
+public final class KotlinDefaultArgumentsFilter implements IFilter {
+
+	static boolean isDefaultArgumentsMethodName(final String methodName) {
+		return methodName.endsWith("$default");
+	}
+
+	public void filter(final MethodNode methodNode,
+			final IFilterContext context, final IFilterOutput output) {
+		if ((methodNode.access & Opcodes.ACC_SYNTHETIC) == 0) {
+			return;
+		}
+		if (!isDefaultArgumentsMethodName(methodNode.name)) {
+			return;
+		}
+		if (!KotlinGeneratedFilter.isKotlinClass(context)) {
+			return;
+		}
+
+		new Matcher().match(methodNode, output);
+	}
+
+	private static class Matcher extends AbstractMatcher {
+		public void match(final MethodNode methodNode,
+				final IFilterOutput output) {
+			cursor = methodNode.instructions.getFirst();
+
+			final Set<AbstractInsnNode> ignore = new HashSet<AbstractInsnNode>();
+			final int maskVar = Type.getMethodType(methodNode.desc)
+					.getArgumentTypes().length - 2;
+			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);
+			}
+		}
+	}
+
+}
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/KotlinGeneratedFilter.java b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/KotlinGeneratedFilter.java
index 68331492..722fd716 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/KotlinGeneratedFilter.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/KotlinGeneratedFilter.java
@@ -23,6 +23,10 @@ public class KotlinGeneratedFilter implements IFilter {
 
 	static final String KOTLIN_METADATA_DESC = "Lkotlin/Metadata;";
 
+	static boolean isKotlinClass(final IFilterContext context) {
+		return context.getClassAnnotations().contains(KOTLIN_METADATA_DESC);
+	}
+
 	public void filter(final MethodNode methodNode,
 			final IFilterContext context, final IFilterOutput output) {
 
@@ -32,7 +36,7 @@ public class KotlinGeneratedFilter implements IFilter {
 			return;
 		}
 
-		if (!context.getClassAnnotations().contains(KOTLIN_METADATA_DESC)) {
+		if (!isKotlinClass(context)) {
 			return;
 		}
 
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/SyntheticFilter.java b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/SyntheticFilter.java
index 52d38bd2..5dfeecf5 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/SyntheticFilter.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/SyntheticFilter.java
@@ -21,11 +21,22 @@ public final class SyntheticFilter implements IFilter {
 
 	public void filter(final MethodNode methodNode,
 			final IFilterContext context, final IFilterOutput output) {
-		if ((methodNode.access & Opcodes.ACC_SYNTHETIC) != 0
-				&& !methodNode.name.startsWith("lambda$")) {
-			output.ignore(methodNode.instructions.getFirst(),
-					methodNode.instructions.getLast());
+		if ((methodNode.access & Opcodes.ACC_SYNTHETIC) == 0) {
+			return;
 		}
+
+		if (methodNode.name.startsWith("lambda$")) {
+			return;
+		}
+
+		if (KotlinDefaultArgumentsFilter
+				.isDefaultArgumentsMethodName(methodNode.name)
+				&& KotlinGeneratedFilter.isKotlinClass(context)) {
+			return;
+		}
+
+		output.ignore(methodNode.instructions.getFirst(),
+				methodNode.instructions.getLast());
 	}
 
 }