| /* |
| * Copyright (c) 2016, 2018, Red Hat, Inc. 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 TestExpandedWBLostNullCheckDep |
| * @summary Logic that moves a null check in the expanded barrier may cause a memory access that doesn't depend on the barrier to bypass the null check |
| * @key gc |
| * @requires vm.gc.Shenandoah & !vm.graal.enabled |
| * @requires vm.flavor == "server" |
| * @run main/othervm -XX:-BackgroundCompilation -XX:-UseOnStackReplacement -XX:-TieredCompilation |
| * -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC |
| * -XX:+StressGCM -XX:+StressLCM TestExpandedWBLostNullCheckDep |
| */ |
| |
| public class TestExpandedWBLostNullCheckDep { |
| |
| static void test(int i, int[] arr) { |
| // arr.length depends on a null check for arr |
| if (i < 0 || i >= arr.length) { |
| } |
| // The write barrier here also depends on the null check. The |
| // null check is moved in the barrier to enable implicit null |
| // checks. The null check must not be moved arr.length |
| arr[i] = 0x42; |
| } |
| |
| static public void main(String[] args) { |
| int[] int_arr = new int[10]; |
| for (int i = 0; i < 20000; i++) { |
| test(0, int_arr); |
| } |
| try { |
| test(0, null); |
| } catch (NullPointerException npe) {} |
| } |
| } |
