/*

 * Copyright (c) 2013, 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.

 *

 * 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.

 */

import java.io.BufferedReader;

import java.io.InputStreamReader;

import java.lang.Class;

import java.lang.String;

import java.lang.System;

import java.lang.management.ManagementFactory;

import java.lang.management.RuntimeMXBean;

import java.util.ArrayList;

import java.util.List;

import java.util.concurrent.CyclicBarrier;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import java.lang.reflect.Field;

import java.lang.reflect.Modifier;

import sun.misc.Unsafe;

import jdk.internal.vm.annotation.Contended;

/*

 * @test

 * @bug     8003985

 * @summary Support Contended Annotation - JEP 142

 * @modules java.base/jdk.internal.vm.annotation

 * @run main/othervm -XX:-RestrictContended Basic

 */

public class Basic {

    private static final Unsafe U;

    private static int ADDRESS_SIZE;

    private static int HEADER_SIZE;

    static {

        // steal Unsafe

        try {

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

            unsafe.setAccessible(true);

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

        } catch (NoSuchFieldException | IllegalAccessException e) {

            throw new IllegalStateException(e);

        }

        // When running with CompressedOops on 64-bit platform, the address size

        // reported by Unsafe is still 8, while the real reference fields are 4 bytes long.

        // Try to guess the reference field size with this naive trick.

        try {

            long off1 = U.objectFieldOffset(CompressedOopsClass.class.getField("obj1"));

            long off2 = U.objectFieldOffset(CompressedOopsClass.class.getField("obj2"));

            ADDRESS_SIZE = (int) Math.abs(off2 - off1);

            HEADER_SIZE = (int) Math.min(off1, off2);

        } catch (NoSuchFieldException e) {

            ADDRESS_SIZE = -1;

        }

    }

    static class CompressedOopsClass {

        public Object obj1;

        public Object obj2;

    }

    public static boolean arePaddedPairwise(Class klass, String field1, String field2) throws Exception {

        Field f1 = klass.getDeclaredField(field1);

        Field f2 = klass.getDeclaredField(field2);

        if (isStatic(f1) != isStatic(f2)) {

            return true; // these guys are in naturally disjoint locations

        }

        int diff = offset(f1) - offset(f2);

        if (diff < 0) {

            // f1 is first

            return (offset(f2) - (offset(f1) + getSize(f1))) > 64;

        } else {

            // f2 is first

            return (offset(f1) - (offset(f2) + getSize(f2))) > 64;

        }

    }

    public static boolean isPadded(Class klass, String field1) throws Exception {

        Field f1 = klass.getDeclaredField(field1);

        if (isStatic(f1)) {

            return offset(f1) > 128 + 64;

        }

        return offset(f1) > 64;

    }

    public static boolean sameLayout(Class klass1, Class klass2) throws Exception {

        for (Field f1 : klass1.getDeclaredFields()) {

            Field f2 = klass2.getDeclaredField(f1.getName());

            if (offset(f1) != offset(f2)) {

                return false;

            }

        }

        for (Field f2 : klass1.getDeclaredFields()) {

            Field f1 = klass2.getDeclaredField(f2.getName());

            if (offset(f1) != offset(f2)) {

                return false;

            }

        }

        return true;

    }

    public static boolean isStatic(Field field) {

        return Modifier.isStatic(field.getModifiers());

    }

    public static int offset(Field field) {

        if (isStatic(field)) {

            return (int) U.staticFieldOffset(field);

        } else {

            return (int) U.objectFieldOffset(field);

        }

    }

    public static int getSize(Field field) {

        Class type = field.getType();

        if (type == byte.class)    { return 1; }

        if (type == boolean.class) { return 1; }

        if (type == short.class)   { return 2; }

        if (type == char.class)    { return 2; }

        if (type == int.class)     { return 4; }

        if (type == float.class)   { return 4; }

        if (type == long.class)    { return 8; }

        if (type == double.class)  { return 8; }

        return ADDRESS_SIZE;

    }

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

        boolean endResult = true;

        // --------------- INSTANCE FIELDS ---------------------

        if (arePaddedPairwise(Test1.class, "int1", "int2") ||

                isPadded(Test1.class, "int1") ||

                isPadded(Test1.class, "int2")) {

            System.err.println("Test1 failed");

            endResult &= false;

        }

        if (!arePaddedPairwise(Test2.class, "int1", "int2") ||

                !isPadded(Test2.class, "int1") ||

                isPadded(Test2.class, "int2")) {

            System.err.println("Test2 failed");

            endResult &= false;

        }

        if (!arePaddedPairwise(Test3.class, "int1", "int2") ||

                !isPadded(Test3.class, "int1") ||

                !isPadded(Test3.class, "int2")) {

            System.err.println("Test3 failed");

            endResult &= false;

        }

        if (arePaddedPairwise(Test4.class, "int1", "int2") ||

                !isPadded(Test4.class, "int1") ||

                !isPadded(Test4.class, "int2")) {

            System.err.println("Test4 failed");

            endResult &= false;

        }

        if (!arePaddedPairwise(Test5.class, "int1", "int2") ||

                !isPadded(Test5.class, "int1") ||

                !isPadded(Test5.class, "int2")) {

            System.err.println("Test5 failed");

            endResult &= false;

        }

        if (!arePaddedPairwise(Test6.class, "int1", "int2") ||

                !isPadded(Test6.class, "int1") ||

                !isPadded(Test6.class, "int2")) {

            System.err.println("Test6 failed");

            endResult &= false;

        }

        if (arePaddedPairwise(Test7.class, "int1", "int2") ||

                !isPadded(Test7.class, "int1") ||

                !isPadded(Test7.class, "int2")) {

            System.err.println("Test7 failed");

            endResult &= false;

        }

        if (!arePaddedPairwise(Test8.class, "int1", "int2") ||

                !isPadded(Test8.class, "int1") ||

                !isPadded(Test8.class, "int2")) {

            System.err.println("Test8 failed");

            endResult &= false;

        }

        if (!arePaddedPairwise(Test9.class, "int1", "int2") ||

                !isPadded(Test9.class, "int1") ||

                !isPadded(Test9.class, "int2")) {

            System.err.println("Test9 failed");

            endResult &= false;

        }

        if (!sameLayout(Test4.class, Test7.class)) {

            System.err.println("Test4 and Test7 have different layouts");

            endResult &= false;

        }

        if (!sameLayout(Test5.class, Test6.class)) {

            System.err.println("Test5 and Test6 have different layouts");

            endResult &= false;

        }

        if (!sameLayout(Test8.class, Test9.class)) {

            System.err.println("Test8 and Test9 have different layouts");

            endResult &= false;

        }

        System.out.println(endResult ? "Test PASSES" : "Test FAILS");

        if (!endResult) {

           throw new Error("Test failed");

        }

    }

    // ----------------------------------- INSTANCE FIELDS -----------------------------------------

    // naturally packed

    public static class Test1 {

                                 private int int1;

                                 private int int2;

    }

    // int1 is padded

    public static class Test2 {

        @Contended               private int int1;

                                 private int int2;

    }

    // both fields are padded

    public static class Test3 {

        @Contended               private int int1;

        @Contended               private int int2;

    }

    // fields are padded in the singular group

    public static class Test4 {

        @Contended("sameGroup")  private int int1;

        @Contended("sameGroup")  private int int2;

    }

    // fields are padded in disjoint groups

    public static class Test5 {

        @Contended("diffGroup1") private int int1;

        @Contended("diffGroup2") private int int2;

    }

    // fields are padded in disjoint groups

    public static class Test6 {

        @Contended               private int int1;

        @Contended("diffGroup2") private int int2;

    }

    // fields are padded in the singular group

    @Contended

    public static class Test7 {

                                 private int int1;

                                 private int int2;

    }

    // all fields are padded as the group, and one field is padded specifically

    @Contended

    public static class Test8 {

        @Contended               private int int1;

                                 private int int2;

    }

    // all fields are padded as the group, and one field is padded specifically

    @Contended

    public static class Test9 {

        @Contended("group")      private int int1;

                                 private int int2;

    }

}