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  * @key gc
  28  * @requires vm.gc.Shenandoah
  29  * @modules java.base/jdk.internal.misc:+open
  30  *
  31  * @run main/othervm -XX:-UseOnStackReplacement -XX:-BackgroundCompilation -XX:-TieredCompilation
  32  *                   -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC
  33  *                   TestUnsafeOffheapSwap
  34  */
  35 
  36 import java.util.*;
  37 import jdk.internal.misc.Unsafe;
  38 
  39 public class TestUnsafeOffheapSwap {
  40 
  41     static final int SIZE = 10000;
  42     static final long SEED = 1;
  43 
  44     static final jdk.internal.misc.Unsafe UNSAFE = Unsafe.getUnsafe();
  45     static final int SCALE = UNSAFE.ARRAY_INT_INDEX_SCALE;
  46 
  47     static Memory mem;
  48     static int[] arr;
  49 
  50     public static void main(String[] args) throws Exception {
  51         // Bug is exposed when memory.addr is not known statically
  52         mem = new Memory(SIZE*SCALE);
  53         arr = new int[SIZE];
  54 
  55         for (int i = 0; i < 10; i++) {
  56             test();
  57         }
  58     }
  59 
  60     static void test() {
  61         Random rnd = new Random(SEED);
  62         for (int i = 0; i < SIZE; i++) {
  63             int value = rnd.nextInt();
  64             mem.setInt(i, value);
  65             arr[i] = value;
  66         }
  67 
  68         for (int i = 0; i < SIZE; i++) {
  69             if (arr[i] != mem.getInt(i)) {
  70                 throw new IllegalStateException("TESTBUG: Values mismatch before swaps");
  71             }
  72         }
  73 
  74         for (int i = 1; i < SIZE; i++) {
  75             mem.swap(i - 1, i);
  76             int tmp = arr[i - 1];
  77             arr[i - 1] = arr[i];
  78             arr[i] = tmp;
  79         }
  80 
  81         for (int i = 0; i < SIZE; i++) {
  82             if (arr[i] != mem.getInt(i)) {
  83                 throw new IllegalStateException("Values mismatch after swaps");
  84             }
  85         }
  86     }
  87 
  88     static class Memory {
  89         private final long addr;
  90 
  91         Memory(int size) {
  92             addr = UNSAFE.allocateMemory(size);
  93         }
  94 
  95         public int getInt(int idx) {
  96             return UNSAFE.getInt(addr + idx*SCALE);
  97         }
  98 
  99         public void setInt(int idx, int val) {
 100             UNSAFE.putInt(addr + idx*SCALE, val);
 101         }
 102 
 103         public void swap(int a, int b) {
 104             int tmp = getInt(a);
 105             setInt(a, getInt(b));
 106             setInt(b, tmp);
 107         }
 108     }
 109 }