1 /*
   2  * Copyright (c) 2019, Red Hat, Inc. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 /**
  25  * @test TestUnsafeOffheapSwap
  26  * @summary Miscompilation in Unsafe off-heap swap routines
  27  * @requires vm.gc.Shenandoah
  28  * @modules java.base/jdk.internal.misc:+open
  29  *
  30  * @run main/othervm -XX:-UseOnStackReplacement -XX:-BackgroundCompilation -XX:-TieredCompilation
  31  *                   -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC
  32  *                   TestUnsafeOffheapSwap
  33  */
  34 
  35 import java.util.*;
  36 import jdk.internal.misc.Unsafe;
  37 
  38 public class TestUnsafeOffheapSwap {
  39 
  40     static final int SIZE = 10000;
  41     static final long SEED = 1;
  42 
  43     static final jdk.internal.misc.Unsafe UNSAFE = Unsafe.getUnsafe();
  44     static final int SCALE = UNSAFE.ARRAY_INT_INDEX_SCALE;
  45 
  46     static Memory mem;
  47     static int[] arr;
  48 
  49     public static void main(String[] args) throws Exception {
  50         // Bug is exposed when memory.addr is not known statically
  51         mem = new Memory(SIZE*SCALE);
  52         arr = new int[SIZE];
  53 
  54         for (int i = 0; i < 10; i++) {
  55             test();
  56         }
  57     }
  58 
  59     static void test() {
  60         Random rnd = new Random(SEED);
  61         for (int i = 0; i < SIZE; i++) {
  62             int value = rnd.nextInt();
  63             mem.setInt(i, value);
  64             arr[i] = value;
  65         }
  66 
  67         for (int i = 0; i < SIZE; i++) {
  68             if (arr[i] != mem.getInt(i)) {
  69                 throw new IllegalStateException("TESTBUG: Values mismatch before swaps");
  70             }
  71         }
  72 
  73         for (int i = 1; i < SIZE; i++) {
  74             mem.swap(i - 1, i);
  75             int tmp = arr[i - 1];
  76             arr[i - 1] = arr[i];
  77             arr[i] = tmp;
  78         }
  79 
  80         for (int i = 0; i < SIZE; i++) {
  81             if (arr[i] != mem.getInt(i)) {
  82                 throw new IllegalStateException("Values mismatch after swaps");
  83             }
  84         }
  85     }
  86 
  87     static class Memory {
  88         private final long addr;
  89 
  90         Memory(int size) {
  91             addr = UNSAFE.allocateMemory(size);
  92         }
  93 
  94         public int getInt(int idx) {
  95             return UNSAFE.getInt(addr + idx*SCALE);
  96         }
  97 
  98         public void setInt(int idx, int val) {
  99             UNSAFE.putInt(addr + idx*SCALE, val);
 100         }
 101 
 102         public void swap(int a, int b) {
 103             int tmp = getInt(a);
 104             setInt(a, getInt(b));
 105             setInt(b, tmp);
 106         }
 107     }
 108 }