DuplicateFrameEliminator.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:
 *    Marc R. Hoffmann - initial API and implementation
 *
 *******************************************************************************/
package org.jacoco.core.internal.instr;

import org.objectweb.asm.Handle;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;

/**
 * Eliminates consecutive stackmap frame definitions which causes ASM to create
 * invalid class files. This situation occurs when the original class files
 * contains additional stackmap frames at unexpected offsets, which is case for
 * some class files compiled with ECJ.
 */
class DuplicateFrameEliminator extends MethodVisitor {

	private boolean instruction;

	public DuplicateFrameEliminator(final MethodVisitor mv) {
		super(InstrSupport.ASM_API_VERSION, mv);
		instruction = true;
	}

	@Override
	public void visitFrame(final int type, final int nLocal,
			final Object[] local, final int nStack, final Object[] stack) {
		if (instruction) {
			instruction = false;
			mv.visitFrame(type, nLocal, local, nStack, stack);
		}
	}

	@Override
	public void visitInsn(final int opcode) {
		instruction = true;
		mv.visitInsn(opcode);
	}

	@Override
	public void visitIntInsn(final int opcode, final int operand) {
		instruction = true;
		mv.visitIntInsn(opcode, operand);
	}

	@Override
	public void visitVarInsn(final int opcode, final int var) {
		instruction = true;
		mv.visitVarInsn(opcode, var);
	}

	@Override
	public void visitTypeInsn(final int opcode, final String type) {
		instruction = true;
		mv.visitTypeInsn(opcode, type);
	}

	@Override
	public void visitFieldInsn(final int opcode, final String owner,
			final String name, final String desc) {
		instruction = true;
		mv.visitFieldInsn(opcode, owner, name, desc);
	}

	@Override
	public void visitMethodInsn(final int opcode, final String owner,
			final String name, final String desc, final boolean itf) {
		instruction = true;
		mv.visitMethodInsn(opcode, owner, name, desc, itf);
	}

	@Override
	public void visitInvokeDynamicInsn(final String name, final String desc,
			final Handle bsm, final Object... bsmArgs) {
		instruction = true;
		mv.visitInvokeDynamicInsn(name, desc, bsm, bsmArgs);
	}

	@Override
	public void visitJumpInsn(final int opcode, final Label label) {
		instruction = true;
		mv.visitJumpInsn(opcode, label);
	}

	@Override
	public void visitLdcInsn(final Object cst) {
		instruction = true;
		mv.visitLdcInsn(cst);
	}

	@Override
	public void visitIincInsn(final int var, final int increment) {
		instruction = true;
		mv.visitIincInsn(var, increment);
	}

	@Override
	public void visitTableSwitchInsn(final int min, final int max,
			final Label dflt, final Label... labels) {
		instruction = true;
		mv.visitTableSwitchInsn(min, max, dflt, labels);
	}

	@Override
	public void visitLookupSwitchInsn(final Label dflt, final int[] keys,
			final Label[] labels) {
		instruction = true;
		mv.visitLookupSwitchInsn(dflt, keys, labels);
	}

	@Override
	public void visitMultiANewArrayInsn(final String desc, final int dims) {
		instruction = true;
		mv.visitMultiANewArrayInsn(desc, dims);
	}

}