| /* |
| * Copyright (c) 2015, 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. |
| */ |
| |
| /* |
| * @test |
| * @bug 8077504 |
| * @summary Unsafe load can loose control dependency and cause crash |
| * @run main/othervm -XX:-BackgroundCompilation -XX:-UseOnStackReplacement TestUnsafeLoadControl |
| * |
| */ |
| |
| import java.lang.reflect.Field; |
| import sun.misc.Unsafe; |
| |
| public class TestUnsafeLoadControl { |
| |
| private static final Unsafe UNSAFE; |
| |
| static { |
| try { |
| Field unsafeField = Unsafe.class.getDeclaredField("theUnsafe"); |
| unsafeField.setAccessible(true); |
| UNSAFE = (Unsafe) unsafeField.get(null); |
| } catch(Exception e) { |
| throw new RuntimeException(e); |
| } |
| } |
| |
| static int val; |
| static void test1(int[] a, boolean[] flags, boolean flag, long j) { |
| for (int i = 0; i < 10; i++) { |
| if (flags[i]) { |
| if (flag) { |
| long address = (j << 2) + UNSAFE.ARRAY_INT_BASE_OFFSET; |
| int v = UNSAFE.getInt(a, address); |
| val = v; |
| } |
| } |
| } |
| } |
| |
| static int test2(int[] a, boolean[] flags, boolean flag, long j) { |
| int sum = 0; |
| for (int i = 0; i < 10; i++) { |
| if (flags[i]) { |
| if (flag) { |
| long address = (j << 2) + UNSAFE.ARRAY_INT_BASE_OFFSET; |
| int v = UNSAFE.getInt(a, address); |
| if (v == 0) { |
| sum++; |
| } |
| } |
| } |
| } |
| return sum; |
| } |
| |
| static public void main(String[] args) { |
| boolean[] flags = new boolean[10]; |
| for (int i = 0; i < flags.length; i++) { |
| flags[i] = true; |
| } |
| int[] array = new int[10]; |
| for (int i = 0; i < 20000; i++) { |
| test1(array, flags, true, 0); |
| } |
| for (int i = 0; i < flags.length; i++) { |
| flags[i] = false; |
| } |
| test1(array, flags, true, Long.MAX_VALUE/4); |
| |
| for (int i = 0; i < flags.length; i++) { |
| flags[i] = true; |
| } |
| for (int i = 0; i < 20000; i++) { |
| test2(array, flags, true, 0); |
| } |
| for (int i = 0; i < flags.length; i++) { |
| flags[i] = false; |
| } |
| test2(array, flags, true, Long.MAX_VALUE/4); |
| } |
| } |