/*

 * Copyright 2013 SAP AG.  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

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

 * questions.

 */

/**

 * @test

 * @bug 8007898

 * @summary Incorrect optimization of Memory Barriers in Matcher::post_store_load_barrier().

 * @run main/othervm -Xbatch -XX:+IgnoreUnrecognizedVMOptions -XX:CICompilerCount=1 -XX:+StressGCM -XX:+StressLCM DekkerTest

 * @run main/othervm -Xbatch -XX:+IgnoreUnrecognizedVMOptions -XX:CICompilerCount=1 -XX:+StressGCM -XX:+StressLCM DekkerTest

 * @run main/othervm -Xbatch -XX:+IgnoreUnrecognizedVMOptions -XX:CICompilerCount=1 -XX:+StressGCM -XX:+StressLCM DekkerTest

 * @author Martin Doerr martin DOT doerr AT sap DOT com

 *

 * Run 3 times since the failure is intermittent.

 */

public class DekkerTest {

    /*

      Read After Write Test (basically a simple Dekker test with volatile variables)

      Derived from the original jcstress test, available at:

        http://hg.openjdk.java.net/code-tools/jcstress/file/6c339a5aa00d/

        tests-custom/src/main/java/org/openjdk/jcstress/tests/volatiles/DekkerTest.java

     */

    static final int ITERATIONS = 1000000;

    static class TestData {

        public volatile int a;

        public volatile int b;

    }

    static class ResultData {

        public int a;

        public int b;

    }

    TestData[]   testDataArray;

    ResultData[] results;

    volatile boolean start;

    public DekkerTest() {

        testDataArray = new TestData[ITERATIONS];

        results = new ResultData[ITERATIONS];

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

            testDataArray[i] = new TestData();

            results[i] = new ResultData();

        }

        start = false;

    }

    public void reset() {

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

            testDataArray[i].a = 0;

            testDataArray[i].b = 0;

            results[i].a = 0;

            results[i].b = 0;

        }

        start = false;

    }

    int actor1(TestData t) {

        t.a = 1;

        return t.b;

    }

    int actor2(TestData t) {

        t.b = 1;

        return t.a;

    }

    class Runner1 extends Thread {

        public void run() {

            do {} while (!start);

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

                results[i].a = actor1(testDataArray[i]);

            }

        }

    }

    class Runner2 extends Thread {

        public void run() {

            do {} while (!start);

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

                results[i].b = actor2(testDataArray[i]);

            }

        }

    }

    void testRunner() {

        Thread thread1 = new Runner1();

        Thread thread2 = new Runner2();

        thread1.start();

        thread2.start();

        do {} while (!thread1.isAlive());

        do {} while (!thread2.isAlive());

        start = true;

        Thread.yield();

        try {

            thread1.join();

            thread2.join();

        } catch (InterruptedException e) {

            System.out.println("interrupted!");

            System.exit(1);

        }

    }

    boolean printResult() {

        int[] count = new int[4];

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

            int event_kind = (results[i].a << 1) + results[i].b;

            ++count[event_kind];

        }

        if (count[0] == 0 && count[3] == 0) {

            System.out.println("[not interesting]");

            return false; // not interesting

        }

        String error = (count[0] == 0) ? " ok" : " disallowed!";

        System.out.println("[0,0] " + count[0] + error);

        System.out.println("[0,1] " + count[1]);

        System.out.println("[1,0] " + count[2]);

        System.out.println("[1,1] " + count[3]);

        return (count[0] != 0);

    }

    public static void main(String args[]) {

        DekkerTest test = new DekkerTest();

        final int runs = 30;

        int failed = 0;

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

            test.testRunner();

            if (test.printResult()) {

                failed++;

            }

            test.reset();

        }

        if (failed > 0) {

            throw new InternalError("FAILED. Got " + failed + " failed ITERATIONS");

        }

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

    }

}