/*

 * Copyright (c) 2016, 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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,

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 *

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

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/*

 * @test

 * @bug 8155781

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

 *

 * @run main/bootclasspath/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UnlockDiagnosticVMOptions

 *                                 -XX:-TieredCompilation -Xbatch

 *                                 -XX:CompileCommand=dontinline,compiler.unsafe.OpaqueAccesses::test*

 *                                 compiler.unsafe.OpaqueAccesses

 */

package compiler.unsafe;

import jdk.internal.misc.Unsafe;

import java.lang.reflect.Field;

public class OpaqueAccesses {

    private static final Unsafe UNSAFE = Unsafe.getUnsafe();

    private static final Object INSTANCE = new OpaqueAccesses();

    private static final Object[] ARRAY = new Object[10];

    private static final long F_OFFSET;

    private static final long E_OFFSET;

    static {

        try {

            Field field = OpaqueAccesses.class.getDeclaredField("f");

            F_OFFSET = UNSAFE.objectFieldOffset(field);

            E_OFFSET = UNSAFE.arrayBaseOffset(ARRAY.getClass());

        } catch (NoSuchFieldException e) {

            throw new Error(e);

        }

    }

    private Object f = new Object();

    static Object testFixedOffsetField(Object o) {

        return UNSAFE.getObject(o, F_OFFSET);

    }

    static int testFixedOffsetHeader0(Object o) {

        return UNSAFE.getInt(o, 0);

    }

    static int testFixedOffsetHeader4(Object o) {

        return UNSAFE.getInt(o, 4);

    }

    static Object testFixedBase(long off) {

        return UNSAFE.getObject(INSTANCE, off);

    }

    static Object testOpaque(Object o, long off) {

        return UNSAFE.getObject(o, off);

    }

    static int testFixedOffsetHeaderArray0(Object[] arr) {

        return UNSAFE.getInt(arr, 0);

    }

    static int testFixedOffsetHeaderArray4(Object[] arr) {

        return UNSAFE.getInt(arr, 4);

    }

    static Object testFixedOffsetArray(Object[] arr) {

        return UNSAFE.getObject(arr, E_OFFSET);

    }

    static Object testFixedBaseArray(long off) {

        return UNSAFE.getObject(ARRAY, off);

    }

    static Object testOpaqueArray(Object[] o, long off) {

        return UNSAFE.getObject(o, off);

    }

    static final long ADDR = UNSAFE.allocateMemory(10);

    static boolean flag;

    static int testMixedAccess() {

        flag = !flag;

        Object o = (flag ? INSTANCE : null);

        long off = (flag ? F_OFFSET : ADDR);

        return UNSAFE.getInt(o, off);

    }

    public static void main(String[] args) {

        for (int i = 0; i < 20_000; i++) {

            // Instance

            testFixedOffsetField(INSTANCE);

            testFixedOffsetHeader0(INSTANCE);

            testFixedOffsetHeader4(INSTANCE);

            testFixedBase(F_OFFSET);

            testOpaque(INSTANCE, F_OFFSET);

            testMixedAccess();

            // Array

            testFixedOffsetHeaderArray0(ARRAY);

            testFixedOffsetHeaderArray4(ARRAY);

            testFixedOffsetArray(ARRAY);

            testFixedBaseArray(E_OFFSET);

            testOpaqueArray(ARRAY, E_OFFSET);

        }

        System.out.println("TEST PASSED");

    }

}