Yak shaving: add ability to merge coverage of several instructions (#601)

This is required for implementation of filter of duplicate blocks that
compilers generate for `finally`.

6 files changed, 127 insertions, 23 deletions

diff --git a/org.jacoco.core/src/org/jacoco/core/internal/analysis/ClassAnalyzer.java b/org.jacoco.core/src/org/jacoco/core/internal/analysis/ClassAnalyzer.java
index fa3517b6..69a10e7e 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/analysis/ClassAnalyzer.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/analysis/ClassAnalyzer.java
@@ -12,6 +12,7 @@
 package org.jacoco.core.internal.analysis;
 
 import org.jacoco.core.analysis.IMethodCoverage;
+import org.jacoco.core.internal.analysis.filter.Filters;
 import org.jacoco.core.internal.flow.ClassProbesVisitor;
 import org.jacoco.core.internal.flow.MethodProbesVisitor;
 import org.jacoco.core.internal.instr.InstrSupport;
@@ -65,7 +66,7 @@ public class ClassAnalyzer extends ClassProbesVisitor {
 
 		return new MethodAnalyzer(coverage.getName(), coverage.getSuperName(),
 				stringPool.get(name), stringPool.get(desc),
-				stringPool.get(signature), probes) {
+				stringPool.get(signature), probes, Filters.ALL) {
 			@Override
 			public void visitEnd() {
 				super.visitEnd();
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 e216bb77..0be47158 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
@@ -12,23 +12,17 @@
 package org.jacoco.core.internal.analysis;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 import org.jacoco.core.analysis.ICounter;
 import org.jacoco.core.analysis.IMethodCoverage;
 import org.jacoco.core.analysis.ISourceNode;
-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.StringSwitchJavacFilter;
-import org.jacoco.core.internal.analysis.filter.SynchronizedFilter;
-import org.jacoco.core.internal.analysis.filter.SyntheticFilter;
-import org.jacoco.core.internal.analysis.filter.TryWithResourcesEcjFilter;
-import org.jacoco.core.internal.analysis.filter.TryWithResourcesJavacFilter;
 import org.jacoco.core.internal.flow.IFrame;
 import org.jacoco.core.internal.flow.Instruction;
 import org.jacoco.core.internal.flow.LabelInfo;
@@ -47,18 +41,14 @@ import org.objectweb.asm.tree.TryCatchBlockNode;
 public class MethodAnalyzer extends MethodProbesVisitor
 		implements IFilterOutput {
 
-	private static final IFilter[] FILTERS = new IFilter[] { new EnumFilter(),
-			new SyntheticFilter(), new SynchronizedFilter(),
-			new TryWithResourcesJavacFilter(), new TryWithResourcesEcjFilter(),
-			new PrivateEmptyNoArgConstructorFilter(),
-			new StringSwitchJavacFilter(), new LombokGeneratedFilter() };
-
 	private final String className;
 
 	private final String superClassName;
 
 	private final boolean[] probes;
 
+	private final IFilter filter;
+
 	private final MethodCoverageImpl coverage;
 
 	private int currentLine = ISourceNode.UNKNOWN_LINE;
@@ -95,18 +85,20 @@ public class MethodAnalyzer extends MethodProbesVisitor
 	 *            method descriptor
 	 * @param signature
 	 *            optional parameterized signature
-	 * 
 	 * @param probes
 	 *            recorded probe date of the containing class or
 	 *            <code>null</code> if the class is not executed at all
+	 * @param filter
+	 *            filter
 	 */
-	public MethodAnalyzer(final String className, final String superClassName,
+	MethodAnalyzer(final String className, final String superClassName,
 			final String name, final String desc, final String signature,
-			final boolean[] probes) {
+			final boolean[] probes, final IFilter filter) {
 		super();
 		this.className = className;
 		this.superClassName = superClassName;
 		this.probes = probes;
+		this.filter = filter;
 		this.coverage = new MethodCoverageImpl(name, desc, signature);
 	}
 
@@ -126,11 +118,9 @@ public class MethodAnalyzer extends MethodProbesVisitor
 	@Override
 	public void accept(final MethodNode methodNode,
 			final MethodVisitor methodVisitor) {
-		this.ignored.clear();
-		for (final IFilter filter : FILTERS) {
-			filter.filter(className, superClassName, methodNode, this);
-		}
+		filter.filter(className, superClassName, methodNode, this);
 
+		methodVisitor.visitCode();
 		for (final TryCatchBlockNode n : methodNode.tryCatchBlocks) {
 			n.accept(methodVisitor);
 		}
@@ -143,6 +133,22 @@ public class MethodAnalyzer extends MethodProbesVisitor
 	}
 
 	private final Set<AbstractInsnNode> ignored = new HashSet<AbstractInsnNode>();
+
+	/**
+	 * Instructions that should be merged form disjoint sets. Coverage
+	 * information from instructions of one set will be merged into
+	 * representative instruction of set.
+	 * 
+	 * Each such set is represented as a singly linked list: each element except
+	 * one references another element from the same set, element without
+	 * reference - is a representative of this set.
+	 * 
+	 * This map stores reference (value) for elements of sets (key).
+	 */
+	private final Map<AbstractInsnNode, AbstractInsnNode> merged = new HashMap<AbstractInsnNode, AbstractInsnNode>();
+
+	private final Map<AbstractInsnNode, Instruction> nodeToInstruction = new HashMap<AbstractInsnNode, Instruction>();
+
 	private AbstractInsnNode currentNode;
 
 	public void ignore(final AbstractInsnNode fromInclusive,
@@ -154,6 +160,23 @@ public class MethodAnalyzer extends MethodProbesVisitor
 		ignored.add(toInclusive);
 	}
 
+	private AbstractInsnNode findRepresentative(AbstractInsnNode i) {
+		AbstractInsnNode r = merged.get(i);
+		while (r != null) {
+			i = r;
+			r = merged.get(i);
+		}
+		return i;
+	}
+
+	public void merge(AbstractInsnNode i1, AbstractInsnNode i2) {
+		i1 = findRepresentative(i1);
+		i2 = findRepresentative(i2);
+		if (i1 != i2) {
+			merged.put(i2, i1);
+		}
+	}
+
 	@Override
 	public void visitLabel(final Label label) {
 		currentLabel.add(label);
@@ -175,6 +198,7 @@ public class MethodAnalyzer extends MethodProbesVisitor
 
 	private void visitInsn() {
 		final Instruction insn = new Instruction(currentNode, currentLine);
+		nodeToInstruction.put(currentNode, insn);
 		instructions.add(insn);
 		if (lastInsn != null) {
 			insn.setPredecessor(lastInsn, 0);
@@ -342,6 +366,15 @@ public class MethodAnalyzer extends MethodProbesVisitor
 		for (final CoveredProbe p : coveredProbes) {
 			p.instruction.setCovered(p.branch);
 		}
+		// Merge:
+		for (final Instruction i : instructions) {
+			final AbstractInsnNode m = i.getNode();
+			final AbstractInsnNode r = findRepresentative(m);
+			if (r != m) {
+				ignored.add(m);
+				nodeToInstruction.get(r).merge(i);
+			}
+		}
 		// Report result:
 		coverage.ensureCapacity(firstLine, lastLine);
 		for (final Instruction i : instructions) {
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
new file mode 100644
index 00000000..e2c26d92
--- /dev/null
+++ b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/Filters.java
@@ -0,0 +1,48 @@
+/*******************************************************************************
+ * 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.tree.MethodNode;
+
+/**
+ * Filter that combines other filters.
+ */
+public final class Filters implements IFilter {
+
+	/**
+	 * Filter that does nothing.
+	 */
+	public static final IFilter NONE = new Filters();
+
+	/**
+	 * Filter that combines all other filters.
+	 */
+	public static final IFilter ALL = new Filters(new EnumFilter(),
+			new SyntheticFilter(), new SynchronizedFilter(),
+			new TryWithResourcesJavacFilter(), new TryWithResourcesEcjFilter(),
+			new PrivateEmptyNoArgConstructorFilter(),
+			new StringSwitchJavacFilter(), new LombokGeneratedFilter());
+
+	private final IFilter[] filters;
+
+	private Filters(IFilter... filters) {
+		this.filters = filters;
+	}
+
+	public void filter(final String className, final String superClassName,
+			final MethodNode methodNode, final IFilterOutput output) {
+		for (final IFilter filter : filters) {
+			filter.filter(className, superClassName, methodNode, output);
+		}
+	}
+
+}
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/IFilterOutput.java b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/IFilterOutput.java
index c24dc03d..cf25a0a2 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/IFilterOutput.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/IFilterOutput.java
@@ -30,4 +30,15 @@ public interface IFilterOutput {
 	 */
 	void ignore(AbstractInsnNode fromInclusive, AbstractInsnNode toInclusive);
 
+	/**
+	 * Marks two instructions that should be merged during computation of
+	 * coverage.
+	 * 
+	 * @param i1
+	 *            first instruction
+	 * @param i2
+	 *            second instruction
+	 */
+	void merge(AbstractInsnNode i1, AbstractInsnNode i2);
+
 }
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/LombokGeneratedFilter.java b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/LombokGeneratedFilter.java
index 571e4641..98575e80 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/LombokGeneratedFilter.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/LombokGeneratedFilter.java
@@ -19,7 +19,7 @@ import org.objectweb.asm.tree.MethodNode;
 /**
  * Filters methods annotated with <code>@lombok.Generated</code>.
  */
-public class LombokGeneratedFilter implements IFilter {
+public final class LombokGeneratedFilter implements IFilter {
 
 	public void filter(final String className, final String superClassName,
 			final MethodNode methodNode, final IFilterOutput output) {
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/flow/Instruction.java b/org.jacoco.core/src/org/jacoco/core/internal/flow/Instruction.java
index 4f550407..bee274db 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/flow/Instruction.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/flow/Instruction.java
@@ -130,6 +130,17 @@ public class Instruction {
 		return coveredBranches.cardinality();
 	}
 
+	/**
+	 * Merges information about covered branches of given instruction into this
+	 * instruction.
+	 * 
+	 * @param instruction
+	 *            instruction from which to merge
+	 */
+	public void merge(Instruction instruction) {
+		this.coveredBranches.or(instruction.coveredBranches);
+	}
+
 	@Override
 	public String toString() {
 		return coveredBranches.toString();