Java example source code file (Test8010927.java)

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Java - Java tags/keywords

error, exception, field, long, object, reflection, test8010927, unsafe, whitebox

The Test8010927.java Java example source code

/*
 * Copyright (c) 2013, 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 8010927
 * @summary Kitchensink crashed with SIGSEGV, Problematic frame: v ~StubRoutines::checkcast_arraycopy
 * @library /testlibrary/whitebox /testlibrary
 * @build Test8010927
 * @run main ClassFileInstaller sun.hotspot.WhiteBox
 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+IgnoreUnrecognizedVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:. -Xmx64m -XX:NewSize=20971520 -XX:MaxNewSize=32m -XX:-UseTLAB -XX:-UseParNewGC -XX:-UseAdaptiveSizePolicy Test8010927
 */

import sun.hotspot.WhiteBox;
import java.lang.reflect.Field;
import sun.misc.Unsafe;

/**
 * The test creates uncommitted space between oldgen and young gen
 * by specifying MaxNewSize bigger than NewSize.
 * NewSize = 20971520 = (512*4K) * 10 for 4k pages
 * Then it tries to execute arraycopy() with elements type check
 * to the array at the end of survive space near unused space.
 */

public class Test8010927 {

  private static final Unsafe U;

  static {
    try {
      Field unsafe = Unsafe.class.getDeclaredField("theUnsafe");
      unsafe.setAccessible(true);
      U = (Unsafe) unsafe.get(null);
    } catch (Exception e) {
      throw new Error(e);
    }
  }

  public static Object[] o;

  public static final boolean debug = Boolean.getBoolean("debug");

  // 2 different obect arrays but same element types
  static Test8010927[] masterA;
  static Object[] masterB;
  static final Test8010927 elem = new Test8010927();
  static final WhiteBox wb = WhiteBox.getWhiteBox();

  static final int obj_header_size = U.ARRAY_OBJECT_BASE_OFFSET;
  static final int heap_oop_size = wb.getHeapOopSize();
  static final int card_size = 512;
  static final int one_card = (card_size - obj_header_size)/heap_oop_size;

  static final int surv_size = 2112 * 1024;

  // The size is big to not fit into survive space.
  static final Object[] cache = new Object[(surv_size / card_size)];

  public static void main(String[] args) {
    masterA = new Test8010927[one_card];
    masterB = new Object[one_card];
    for (int i = 0; i < one_card; ++i) {
      masterA[i] = elem;
      masterB[i] = elem;
    }

    // Move cache[] to the old gen.
    long low_limit = wb.getObjectAddress(cache);
    System.gc();
    // Move 'cache' to oldgen.
    long upper_limit = wb.getObjectAddress(cache);
    if ((low_limit - upper_limit) > 0) { // substaction works with unsigned values
      // OldGen is placed before youngger for ParallelOldGC.
      upper_limit = low_limit + 21000000l; // +20971520
    }
    // Each A[one_card] size is 512 bytes,
    // it will take about 40000 allocations to trigger GC.
    // cache[] has 8192 elements so GC should happen
    // each 5th iteration.
    for(long l = 0; l < 20; l++) {
      fill_heap();
      if (debug) {
        System.out.println("test oop_disjoint_arraycopy");
      }
      testA_arraycopy();
      if (debug) {
        System.out.println("test checkcast_arraycopy");
      }
      testB_arraycopy();
      // Execute arraycopy to the topmost array in young gen
      if (debug) {
        int top_index = get_top_address(low_limit, upper_limit);
        if (top_index >= 0) {
          long addr = wb.getObjectAddress(cache[top_index]);
          System.out.println("top_addr: 0x" + Long.toHexString(addr) + ", 0x" + Long.toHexString(addr + 512));
        }
      }
    }
  }
  static void fill_heap() {
    for (int i = 0; i < cache.length; ++i) {
      o = new Test8010927[one_card];
      System.arraycopy(masterA, 0, o, 0, masterA.length);
      cache[i] = o;
    }
    for (long j = 0; j < 256; ++j) {
      o = new Long[10000]; // to trigger GC
    }
  }
  static void testA_arraycopy() {
    for (int i = 0; i < cache.length; ++i) {
      System.arraycopy(masterA, 0, cache[i], 0, masterA.length);
    }
  }
  static void testB_arraycopy() {
    for (int i = 0; i < cache.length; ++i) {
      System.arraycopy(masterB, 0, cache[i], 0, masterB.length);
    }
  }
  static int get_top_address(long min, long max) {
    int index = -1;
    long addr = min;
    for (int i = 0; i < cache.length; ++i) {
      long test = wb.getObjectAddress(cache[i]);
      if (((test - addr) > 0) && ((max - test) > 0)) { // substaction works with unsigned values
        addr = test;
        index = i;
      }
    }
    return index;
  }
}