1 /*
   2  * Copyright (c) 2014, Oracle and/or its affiliates. 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 TestDeferredRSUpdate
  26  * @bug 8040977 8052170
  27  * @summary Ensure that running with -XX:-G1DeferredRSUpdate does not crash the VM
  28  * @key gc
  29  * @library /testlibrary
  30  */
  31 
  32 import com.oracle.java.testlibrary.ProcessTools;
  33 import com.oracle.java.testlibrary.OutputAnalyzer;
  34 
  35 public class TestDeferredRSUpdate {
  36   public static void main(String[] args) throws Exception {
  37     GCTest.main(args);
  38 
  39     ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-XX:+UseG1GC",
  40                                                               "-Xmx10M",
  41                                                               "-XX:+PrintGCDetails",
  42                                                               // G1DeferredRSUpdate is a develop option, but we cannot limit execution of this test to only debug VMs.
  43                                                               "-XX:+IgnoreUnrecognizedVMOptions",
  44                                                               "-XX:-G1DeferredRSUpdate",
  45                                                               GCTest.class.getName());
  46 
  47     OutputAnalyzer output = new OutputAnalyzer(pb.start());
  48     output.shouldHaveExitValue(0);
  49   }
  50 
  51   static class GCTest {
  52     private static Object[] garbage = new Object[32];
  53 
  54     public static void main(String [] args) {
  55       System.out.println("Creating garbage");
  56       // Create 128MB of garbage. This should result in at least one minor GC, with
  57       // some objects copied to old gen. As references from old to young are installed,
  58       // the crash due to the use before initialize occurs.
  59       Object prev = null;
  60       Object prevPrev = null;
  61       for (int i = 0; i < 1024; i++) {
  62         Object[] next = new Object[32 * 1024];
  63         next[0] = prev;
  64         next[1] = prevPrev;
  65 
  66         Object[] cur = (Object[]) garbage[i % garbage.length];
  67         if (cur != null) {
  68           cur[0] = null;
  69           cur[1] = null;
  70         }
  71         garbage[i % garbage.length] = next;
  72 
  73         prevPrev = prev;
  74         prev = next;
  75       }
  76       System.out.println("Done");
  77     }
  78   }
  79 }