Add filter for private empty constructors that do not have arguments (#529)

3 files changed, 66 insertions, 5 deletions

diff --git a/org.jacoco.core/src/org/jacoco/core/internal/analysis/MethodAnalyzer.java b/org.jacoco.core/src/org/jacoco/core/internal/analysis/MethodAnalyzer.java
index ee051436..8e07e56f 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/analysis/MethodAnalyzer.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/analysis/MethodAnalyzer.java
@@ -23,6 +23,7 @@ import org.jacoco.core.internal.analysis.filter.EnumFilter;
 import org.jacoco.core.internal.analysis.filter.IFilter;
 import org.jacoco.core.internal.analysis.filter.IFilterOutput;
 import org.jacoco.core.internal.analysis.filter.LombokGeneratedFilter;
+import org.jacoco.core.internal.analysis.filter.PrivateEmptyNoArgConstructorFilter;
 import org.jacoco.core.internal.analysis.filter.SynchronizedFilter;
 import org.jacoco.core.internal.analysis.filter.SyntheticFilter;
 import org.jacoco.core.internal.analysis.filter.TryWithResourcesEcjFilter;
@@ -48,7 +49,7 @@ public class MethodAnalyzer extends MethodProbesVisitor
 	private static final IFilter[] FILTERS = new IFilter[] { new EnumFilter(),
 			new SyntheticFilter(), new SynchronizedFilter(),
 			new TryWithResourcesJavacFilter(), new TryWithResourcesEcjFilter(),
-			new LombokGeneratedFilter() };
+			new PrivateEmptyNoArgConstructorFilter(), new LombokGeneratedFilter() };
 
 	private final String className;
 
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 e4958bdb..50a295de 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
@@ -73,11 +73,16 @@ abstract class AbstractMatcher {
 		if (cursor == null) {
 			return;
 		}
-		do {
-			cursor = cursor.getNext();
-		} while (cursor != null && (cursor.getType() == AbstractInsnNode.FRAME
+		cursor = cursor.getNext();
+		skipNonOpcodes();
+	}
+
+	final void skipNonOpcodes() {
+		while (cursor != null && (cursor.getType() == AbstractInsnNode.FRAME
 				|| cursor.getType() == AbstractInsnNode.LABEL
-				|| cursor.getType() == AbstractInsnNode.LINE));
+				|| cursor.getType() == AbstractInsnNode.LINE)) {
+			cursor = cursor.getNext();
+		}
 	}
 
 }
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/PrivateEmptyNoArgConstructorFilter.java b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/PrivateEmptyNoArgConstructorFilter.java
new file mode 100644
index 00000000..9e1bd43c
--- /dev/null
+++ b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/PrivateEmptyNoArgConstructorFilter.java
@@ -0,0 +1,55 @@
+/*******************************************************************************
+ * Copyright (c) 2009, 2017 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 org.objectweb.asm.Opcodes;
+import org.objectweb.asm.tree.MethodInsnNode;
+import org.objectweb.asm.tree.MethodNode;
+import org.objectweb.asm.tree.VarInsnNode;
+
+/**
+ * Filters private empty constructors that do not have arguments.
+ */
+public final class PrivateEmptyNoArgConstructorFilter implements IFilter {
+
+	public void filter(final String className, final String superClassName,
+			final MethodNode methodNode, final IFilterOutput output) {
+		if ((methodNode.access & Opcodes.ACC_PRIVATE) != 0
+				&& "<init>".equals(methodNode.name)
+				&& "()V".equals(methodNode.desc)
+				&& new Matcher().match(methodNode, superClassName)) {
+			output.ignore(methodNode.instructions.getFirst(),
+					methodNode.instructions.getLast());
+		}
+	}
+
+	private static class Matcher extends AbstractMatcher {
+		private boolean match(final MethodNode methodNode,
+				final String superClassName) {
+			cursor = methodNode.instructions.getFirst();
+			skipNonOpcodes();
+			if (cursor.getOpcode() != Opcodes.ALOAD
+					|| ((VarInsnNode) cursor).var != 0) {
+				return false;
+			}
+			nextIs(Opcodes.INVOKESPECIAL);
+			MethodInsnNode m = (MethodInsnNode) cursor;
+			if (m != null && superClassName.equals(m.owner)
+					&& "<init>".equals(m.name) && ("()V").equals(m.desc)) {
+				nextIs(Opcodes.RETURN);
+				return cursor != null;
+			}
+			return false;
+		}
+	}
+
+}