/*

 * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

/*

 * @test

 * @bug 8016474

 * @summary The bug only happens with C1 and G1 using a different ObjectAlignmentInBytes than KlassAlignmentInBytes (which is 8)

 * @modules java.base/jdk.internal.misc

 * @run main/othervm -Xbatch -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=32 GetUnsafeObjectG1PreBarrier

 */

import java.lang.reflect.Field;

public class GetUnsafeObjectG1PreBarrier {

    private static final Unsafe unsafe;

    private static final int N = 100_000;

    static {

        try {

            Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");

            theUnsafe.setAccessible(true);

            unsafe = (Unsafe) theUnsafe.get(null);

        } catch (NoSuchFieldException | IllegalAccessException e) {

            throw new IllegalStateException(e);

        }

    }

    public Object a;

    public static void main(String[] args) throws Throwable {

        new GetUnsafeObjectG1PreBarrier();

    }

    public GetUnsafeObjectG1PreBarrier() throws Throwable {

        doit();

    }

    private void doit() throws Throwable {

        Field field = GetUnsafeObjectG1PreBarrier.class.getField("a");

        long fieldOffset = unsafe.objectFieldOffset(field);

        for (int i = 0; i < N; i++) {

            readField(this, fieldOffset);

        }

    }

    private void readField(Object o, long fieldOffset) {

        unsafe.getObject(o, fieldOffset);

    }

}