1 /*
   2  * Copyright (c) 2020, 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
  26  * @bug 8237837 8244721
  27  * @summary  Shenandoah: assert(mem == __null) failed: only one safepoint
  28  * @key gc
  29  * @requires vm.flavor == "server"
  30  * @requires vm.gc.Shenandoah & !vm.graal.enabled
  31  *
  32  * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -Xcomp -XX:CompileOnly=BarrierInInfiniteLoop::test1
  33  *                   -XX:CompileOnly=BarrierInInfiniteLoop::test2 -XX:CompileOnly=BarrierInInfiniteLoop::test3 -XX:CompileCommand=quiet BarrierInInfiniteLoop
  34  *
  35  */
  36 
  37 public class BarrierInInfiniteLoop {
  38     private static Object field1 = new Object();
  39     private static Object field2 = new Object();
  40     private static int field3;
  41 
  42     public static void main(String[] args) {
  43         test1(false);
  44         test2(false, false);
  45         test3(false);
  46     }
  47 
  48     private static void test1(boolean flag) {
  49         if (flag) {
  50             for (;;) {
  51                 field1 = field2;
  52             }
  53         }
  54     }
  55 
  56     private static void test2(boolean flag1, boolean flag2) {
  57         if (flag1) {
  58             for (;;) {
  59                 for (;;) {
  60                     if (flag2) {
  61                         break;
  62                     }
  63                     field1 = field2;
  64                 }
  65             }
  66         }
  67     }
  68 
  69     private static void test3(boolean flag) {
  70         if (flag) {
  71             for (;;) {
  72                 for (;;) {
  73                     field3 = 42;
  74                     if (field1 == field2) {
  75                         break;
  76                     }
  77                 }
  78             }
  79         }
  80     }
  81 }