/*

 * Copyright (c) 2016, 2018, Red Hat, Inc. All rights reserved.

 *

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

/*

 * Run standalone with: --add-exports java.base/jdk.internal.misc=ALL-UNNAMED --add-opens java.base/jdk.internal.misc=ALL-UNNAMED

 */

/*

 * @test TestReferenceCAS

 * @summary Shenandoah reference CAS test

 * @key gc

 * @requires vm.gc.Shenandoah

 * @modules java.base/jdk.internal.misc:+open

 *

 * @run main/othervm -Diters=20000 -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:ShenandoahGCHeuristics=aggressive -XX:+UseShenandoahGC                                                 TestReferenceCAS

 * @run main/othervm -Diters=100   -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:ShenandoahGCHeuristics=aggressive -XX:+UseShenandoahGC -Xint                                           TestReferenceCAS

 * @run main/othervm -Diters=20000 -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:ShenandoahGCHeuristics=aggressive -XX:+UseShenandoahGC -XX:-TieredCompilation                          TestReferenceCAS

 * @run main/othervm -Diters=20000 -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:ShenandoahGCHeuristics=aggressive -XX:+UseShenandoahGC -XX:TieredStopAtLevel=1                         TestReferenceCAS

 * @run main/othervm -Diters=20000 -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:ShenandoahGCHeuristics=aggressive -XX:+UseShenandoahGC -XX:TieredStopAtLevel=4                         TestReferenceCAS

 *

 * @run main/othervm -Diters=20000 -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:ShenandoahGCHeuristics=aggressive -XX:+UseShenandoahGC -XX:-UseCompressedOops                          TestReferenceCAS

 * @run main/othervm -Diters=100   -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:ShenandoahGCHeuristics=aggressive -XX:+UseShenandoahGC -XX:-UseCompressedOops -Xint                    TestReferenceCAS

 * @run main/othervm -Diters=20000 -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:ShenandoahGCHeuristics=aggressive -XX:+UseShenandoahGC -XX:-UseCompressedOops -XX:-TieredCompilation   TestReferenceCAS

 * @run main/othervm -Diters=20000 -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:ShenandoahGCHeuristics=aggressive -XX:+UseShenandoahGC -XX:-UseCompressedOops -XX:TieredStopAtLevel=1  TestReferenceCAS

 * @run main/othervm -Diters=20000 -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:ShenandoahGCHeuristics=aggressive -XX:+UseShenandoahGC -XX:-UseCompressedOops -XX:TieredStopAtLevel=4  TestReferenceCAS

 */

import java.lang.reflect.Field;

public class TestReferenceCAS {

    static final int ITERS = Integer.getInteger("iters", 1);

    static final int WEAK_ATTEMPTS = Integer.getInteger("weakAttempts", 10);

    static final jdk.internal.misc.Unsafe UNSAFE;

    static final long V_OFFSET;

    static {

        try {

            Field f = jdk.internal.misc.Unsafe.class.getDeclaredField("theUnsafe");

            f.setAccessible(true);

            UNSAFE = (jdk.internal.misc.Unsafe) f.get(null);

        } catch (Exception e) {

            throw new RuntimeException("Unable to get Unsafe instance.", e);

        }

        try {

            Field vField = TestReferenceCAS.class.getDeclaredField("v");

            V_OFFSET = UNSAFE.objectFieldOffset(vField);

        } catch (Exception e) {

            throw new RuntimeException(e);

        }

    }

    Object v;

    private static void assertEquals(boolean a, boolean b, String msg) {

        if (a != b) {

            throw new RuntimeException("a (" + a + ") != b (" + b + "): " + msg);

        }

    }

    private static void assertEquals(Object a, Object b, String msg) {

        if (!a.equals(b)) {

            throw new RuntimeException("a (" + a.toString() + ") != b (" + b.toString() + "): " + msg);

        }

    }

    public static void main(String[] args) {

        TestReferenceCAS t = new TestReferenceCAS();

        for (int c = 0; c < ITERS; c++) {

            testAccess(t, V_OFFSET);

        }

    }

    static void testAccess(Object base, long offset) {

        String foo = new String("foo");

        String bar = new String("bar");

        String baz = new String("baz");

        UNSAFE.putReference(base, offset, "foo");

        {

            String newval = bar;

            boolean r = UNSAFE.compareAndSetReference(base, offset, "foo", newval);

            assertEquals(r, true, "success compareAndSet Object");

            assertEquals(newval, "bar", "must not destroy newval");

            Object x = UNSAFE.getReference(base, offset);

            assertEquals(x, "bar", "success compareAndSet Object value");

        }

        {

            String newval = baz;

            boolean r = UNSAFE.compareAndSetReference(base, offset, "foo", newval);

            assertEquals(r, false, "failing compareAndSet Object");

            assertEquals(newval, "baz", "must not destroy newval");

            Object x = UNSAFE.getReference(base, offset);

            assertEquals(x, "bar", "failing compareAndSet Object value");

        }

        UNSAFE.putReference(base, offset, "bar");

        {

            String newval = foo;

            Object r = UNSAFE.compareAndExchangeReference(base, offset, "bar", newval);

            assertEquals(r, "bar", "success compareAndExchange Object");

            assertEquals(newval, "foo", "must not destroy newval");

            Object x = UNSAFE.getReference(base, offset);

            assertEquals(x, "foo", "success compareAndExchange Object value");

        }

        {

            String newval = baz;

            Object r = UNSAFE.compareAndExchangeReference(base, offset, "bar", newval);

            assertEquals(r, "foo", "failing compareAndExchange Object");

            assertEquals(newval, "baz", "must not destroy newval");

            Object x = UNSAFE.getReference(base, offset);

            assertEquals(x, "foo", "failing compareAndExchange Object value");

        }

        UNSAFE.putReference(base, offset, "bar");

        {

            String newval = foo;

            boolean success = false;

            for (int c = 0; c < WEAK_ATTEMPTS && !success; c++) {

                success = UNSAFE.weakCompareAndSetReference(base, offset, "bar", newval);

                assertEquals(newval, "foo", "must not destroy newval");

            }

            assertEquals(success, true, "weakCompareAndSet Object");

            Object x = UNSAFE.getReference(base, offset);

            assertEquals(x, "foo", "weakCompareAndSet Object");

        }

    }

}