/*

 * Copyright (c) 2014 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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 */

package org.openjdk.bench.vm.compiler;

import org.openjdk.jmh.annotations.Benchmark;

import org.openjdk.jmh.annotations.BenchmarkMode;

import org.openjdk.jmh.annotations.Mode;

import org.openjdk.jmh.annotations.OutputTimeUnit;

import org.openjdk.jmh.annotations.Scope;

import org.openjdk.jmh.annotations.State;

import java.util.concurrent.TimeUnit;

/**

 * Tests for removal of redundant stores. It's crucial for the tests to be valid that inlining and allocation is

 * performed as described in this file.

 */

@BenchmarkMode(Mode.AverageTime)

@OutputTimeUnit(TimeUnit.NANOSECONDS)

@State(Scope.Thread)

public class StoreAfterStore {

    public int s1 = 1, s2 = 2, s3 = 3, s4 = 4, s5 = 5, s6 = 6, s7 = 7, s8 = 8;

    /**

     * Test removal of redundant zero stores following an object allocation.

     */

    @Benchmark

    public AllocAndZeroStoreHelper testAllocAndZeroStore() throws Exception {

        return new AllocAndZeroStoreHelper(s1, s2, s3, s4, s5, s6, s7, s8);

    }

    /**

     * Test removal of stores followed by stores to the same memory location.

     */

    @Benchmark

    public StoreAndStoreHelper testStoreAndStore() throws Exception {

        return new StoreAndStoreHelper(s1, s2, s3, s4, s5, s6, s7, s8);

    }

    /**

     * Helper for alloc followed by zero store testing.

     */

    static class AllocAndZeroStoreHelper {

        public volatile int vf1, vf2, vf3, vf4, vf5, vf6, vf7, vf8;

        public static int s1, s2, s3, s4, s5, s6, s7, s8;

        private AllocAndZeroStoreHelper() {

            this.vf1 = 0;

            this.vf2 = 0;

            this.vf3 = 0;

            this.vf4 = 0;

            this.vf5 = 0;

            this.vf6 = 0;

            this.vf7 = 0;

            this.vf8 = 0;

        }

        private AllocAndZeroStoreHelper(int l1, int l2, int l3, int l4, int l5, int l6, int l7, int l8) {

            this(); // Redundant initialization to zero here

            // dummy stores

            s1 = l1;

            s2 = l2;

            s3 = l3;

            s4 = l4;

            s5 = l5;

            s6 = l6;

            s7 = l7;

            s8 = l8;

        }

    }

    /**

     * Helper for store made redundant by subsequent store testing.

     */

    static class StoreAndStoreHelper {

        public volatile int vf1, vf2, vf3, vf4, vf5, vf6, vf7, vf8;

        private StoreAndStoreHelper() {

            this.vf1 = -1;

            this.vf2 = -1;

            this.vf3 = -1;

            this.vf4 = -1;

            this.vf5 = -1;

            this.vf6 = -1;

            this.vf7 = -1;

            this.vf8 = -1;

        }

        private StoreAndStoreHelper(int l1, int l2, int l3, int l4, int l5, int l6, int l7, int l8) {

            this(); // Initialize all to -1 here, redundant wrt to the below stores

            this.vf1 = l1;

            this.vf2 = l2;

            this.vf3 = l3;

            this.vf4 = l4;

            this.vf5 = l5;

            this.vf6 = l6;

            this.vf7 = l7;

            this.vf8 = l8;

        }

    }

}