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