No need to modify class bytes for Java 10 support (#740)

7 files changed, 24 insertions, 105 deletions

diff --git a/org.jacoco.core/src/org/jacoco/core/analysis/Analyzer.java b/org.jacoco.core/src/org/jacoco/core/analysis/Analyzer.java
index 92d640d2..01ffd5d3 100644
--- a/org.jacoco.core/src/org/jacoco/core/analysis/Analyzer.java
+++ b/org.jacoco.core/src/org/jacoco/core/analysis/Analyzer.java
@@ -22,7 +22,6 @@ import java.util.zip.ZipInputStream;
 
 import org.jacoco.core.data.ExecutionData;
 import org.jacoco.core.data.ExecutionDataStore;
-import org.jacoco.core.internal.BytecodeVersion;
 import org.jacoco.core.internal.ContentTypeDetector;
 import org.jacoco.core.internal.InputStreams;
 import org.jacoco.core.internal.Pack200Streams;
@@ -113,9 +112,7 @@ public class Analyzer {
 
 	private void analyzeClass(final byte[] source) {
 		final long classId = CRC64.classId(source);
-		final int version = BytecodeVersion.get(source);
-		final byte[] b = BytecodeVersion.downgradeIfNeeded(version, source);
-		final ClassReader reader = new ClassReader(b);
+		final ClassReader reader = new ClassReader(source);
 		if ((reader.getAccess() & Opcodes.ACC_SYNTHETIC) != 0) {
 			return;
 		}
diff --git a/org.jacoco.core/src/org/jacoco/core/instr/Instrumenter.java b/org.jacoco.core/src/org/jacoco/core/instr/Instrumenter.java
index da956fd9..1b18f908 100644
--- a/org.jacoco.core/src/org/jacoco/core/instr/Instrumenter.java
+++ b/org.jacoco.core/src/org/jacoco/core/instr/Instrumenter.java
@@ -21,7 +21,6 @@ import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
 import java.util.zip.ZipOutputStream;
 
-import org.jacoco.core.internal.BytecodeVersion;
 import org.jacoco.core.internal.ContentTypeDetector;
 import org.jacoco.core.internal.InputStreams;
 import org.jacoco.core.internal.Pack200Streams;
@@ -84,10 +83,7 @@ public class Instrumenter {
 
 	private byte[] instrument(final byte[] source) {
 		final long classId = CRC64.classId(source);
-		final int originalVersion = BytecodeVersion.get(source);
-		final byte[] b = BytecodeVersion.downgradeIfNeeded(originalVersion,
-				source);
-		final ClassReader reader = new ClassReader(b);
+		final ClassReader reader = new ClassReader(source);
 		final ClassWriter writer = new ClassWriter(reader, 0) {
 			@Override
 			protected String getCommonSuperClass(final String type1,
@@ -97,13 +93,12 @@ public class Instrumenter {
 		};
 		final IProbeArrayStrategy strategy = ProbeArrayStrategyFactory
 				.createFor(classId, reader, accessorGenerator);
+		final int version = InstrSupport.getVersionMajor(source);
 		final ClassVisitor visitor = new ClassProbesAdapter(
 				new ClassInstrumenter(strategy, writer),
-				InstrSupport.needsFrames(originalVersion));
+				InstrSupport.needsFrames(version));
 		reader.accept(visitor, ClassReader.EXPAND_FRAMES);
-		final byte[] instrumented = writer.toByteArray();
-		BytecodeVersion.set(instrumented, originalVersion);
-		return instrumented;
+		return writer.toByteArray();
 	}
 
 	/**
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/BytecodeVersion.java b/org.jacoco.core/src/org/jacoco/core/internal/BytecodeVersion.java
deleted file mode 100644
index c24828b3..00000000
--- a/org.jacoco.core/src/org/jacoco/core/internal/BytecodeVersion.java
+++ /dev/null
@@ -1,81 +0,0 @@
-/*******************************************************************************
- * 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;
-
-import org.objectweb.asm.Opcodes;
-
-/**
- * Utilities to read and modify bytecode version in bytes of class. Main purpose
- * of this class is to deal with bytecode versions which are not yet supported
- * by ASM.
- */
-public final class BytecodeVersion {
-
-	private static final int VERSION_INDEX = 6;
-
-	/**
-	 * Version of the Java 10 class file format.
-	 */
-	public static final int V10 = Opcodes.V9 + 1;
-
-	private BytecodeVersion() {
-	}
-
-	/**
-	 * Gets major of bytecode version number from given bytes of class.
-	 * 
-	 * @param b
-	 *            bytes of class
-	 * @return version of bytecode
-	 */
-	public static int get(final byte[] b) {
-		return (short) (((b[VERSION_INDEX] & 0xFF) << 8)
-				| (b[VERSION_INDEX + 1] & 0xFF));
-	}
-
-	/**
-	 * Sets major of bytecode version in given bytes of class.
-	 *
-	 * @param b
-	 *            bytes of class
-	 * @param version
-	 *            version of bytecode to set
-	 */
-	public static void set(final byte[] b, final int version) {
-		b[VERSION_INDEX] = (byte) (version >>> 8);
-		b[VERSION_INDEX + 1] = (byte) version;
-	}
-
-	/**
-	 * Returns given bytes of class if its major bytecode version is less that
-	 * {@link #V10}, otherwise returns copy where major version set to
-	 * {@link Opcodes#V9}.
-	 * 
-	 * @param version
-	 *            version of bytecode
-	 * @param source
-	 *            bytes of class
-	 * @return given bytes of class if version is less than {@link #V10},
-	 *         otherwise copy where version set to {@link Opcodes#V9}
-	 */
-	public static byte[] downgradeIfNeeded(final int version,
-			final byte[] source) {
-		if (V10 != version) {
-			return source;
-		}
-		final byte[] b = new byte[source.length];
-		System.arraycopy(source, 0, b, 0, source.length);
-		set(b, Opcodes.V9);
-		return b;
-	}
-
-}
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/ContentTypeDetector.java b/org.jacoco.core/src/org/jacoco/core/internal/ContentTypeDetector.java
index c74d3374..5ef3a9a0 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/ContentTypeDetector.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/ContentTypeDetector.java
@@ -83,7 +83,7 @@ public class ContentTypeDetector {
 			case Opcodes.V1_7:
 			case Opcodes.V1_8:
 			case Opcodes.V9:
-			case BytecodeVersion.V10:
+			case Opcodes.V10:
 			case Opcodes.V11:
 			case Opcodes.V11 | Opcodes.V_PREVIEW_EXPERIMENTAL:
 			case Opcodes.V12:
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/instr/InstrSupport.java b/org.jacoco.core/src/org/jacoco/core/internal/instr/InstrSupport.java
index 1d4cf2a3..c4569c28 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/instr/InstrSupport.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/instr/InstrSupport.java
@@ -13,6 +13,7 @@ package org.jacoco.core.internal.instr;
 
 import static java.lang.String.format;
 
+import org.objectweb.asm.ClassReader;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Opcodes;
 
@@ -157,6 +158,20 @@ public final class InstrSupport {
 	 */
 	static final int CLINIT_ACC = Opcodes.ACC_SYNTHETIC | Opcodes.ACC_STATIC;
 
+	private static final int MAJOR_VERSION_INDEX = 6;
+
+	/**
+	 * Gets major of bytecode version number from given bytes of class.
+	 *
+	 * @param b
+	 *            bytes of class
+	 * @return version of bytecode
+	 */
+	public static int getVersionMajor(final byte[] b) {
+		return (short) (((b[MAJOR_VERSION_INDEX] & 0xFF) << 8)
+				| (b[MAJOR_VERSION_INDEX + 1] & 0xFF));
+	}
+
 	/**
 	 * Determines whether the given class file version requires stackmap frames.
 	 * 
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/instr/ProbeArrayStrategyFactory.java b/org.jacoco.core/src/org/jacoco/core/internal/instr/ProbeArrayStrategyFactory.java
index a4fb82b0..4e1938f2 100644
--- a/org.jacoco.core/src/org/jacoco/core/internal/instr/ProbeArrayStrategyFactory.java
+++ b/org.jacoco.core/src/org/jacoco/core/internal/instr/ProbeArrayStrategyFactory.java
@@ -11,7 +11,6 @@
  *******************************************************************************/
 package org.jacoco.core.internal.instr;
 
-import org.jacoco.core.internal.BytecodeVersion;
 import org.jacoco.core.internal.flow.ClassProbesAdapter;
 import org.jacoco.core.runtime.IExecutionDataAccessorGenerator;
 import org.objectweb.asm.ClassReader;
@@ -44,7 +43,7 @@ public final class ProbeArrayStrategyFactory {
 			final IExecutionDataAccessorGenerator accessorGenerator) {
 
 		final String className = reader.getClassName();
-		final int version = BytecodeVersion.get(reader.b);
+		final int version = InstrSupport.getVersionMajor(reader.b);
 
 		if (isInterfaceOrModule(reader)) {
 			final ProbeCounter counter = getProbeCounter(reader);
diff --git a/org.jacoco.core/src/org/jacoco/core/runtime/ModifiedSystemClassRuntime.java b/org.jacoco.core/src/org/jacoco/core/runtime/ModifiedSystemClassRuntime.java
index e51242d8..6d31358f 100644
--- a/org.jacoco.core/src/org/jacoco/core/runtime/ModifiedSystemClassRuntime.java
+++ b/org.jacoco.core/src/org/jacoco/core/runtime/ModifiedSystemClassRuntime.java
@@ -19,7 +19,6 @@ import java.lang.instrument.Instrumentation;
 import java.lang.reflect.Field;
 import java.security.ProtectionDomain;
 
-import org.jacoco.core.internal.BytecodeVersion;
 import org.jacoco.core.internal.instr.InstrSupport;
 import org.objectweb.asm.ClassReader;
 import org.objectweb.asm.ClassVisitor;
@@ -154,10 +153,7 @@ public class ModifiedSystemClassRuntime extends AbstractRuntime {
 	 */
 	public static byte[] instrument(final byte[] source,
 			final String accessFieldName) {
-		final int originalVersion = BytecodeVersion.get(source);
-		final byte[] b = BytecodeVersion.downgradeIfNeeded(originalVersion,
-				source);
-		final ClassReader reader = new ClassReader(b);
+		final ClassReader reader = new ClassReader(source);
 		final ClassWriter writer = new ClassWriter(reader, 0);
 		reader.accept(new ClassVisitor(InstrSupport.ASM_API_VERSION, writer) {
 
@@ -168,9 +164,7 @@ public class ModifiedSystemClassRuntime extends AbstractRuntime {
 			}
 
 		}, ClassReader.EXPAND_FRAMES);
-		final byte[] instrumented = writer.toByteArray();
-		BytecodeVersion.set(instrumented, originalVersion);
-		return instrumented;
+		return writer.toByteArray();
 	}
 
 	private static void createDataField(final ClassVisitor visitor,