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Java example source code file (TestHumongousCodeCacheRoots.java)

This example Java source code file (TestHumongousCodeCacheRoots.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

arraylist, exception, outputanalyzer, string, testhumongouscodecacherootshelper, util, xbootclasspath\/a, xmx100m, xx\:\+g1verifyheapregioncoderoots, xx\:\+unlockdiagnosticvmoptions, xx\:\+verifyaftergc, xx\:\+whiteboxapi

The TestHumongousCodeCacheRoots.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
 * @key regression
 * @key gc
 * @bug 8027756
 * @library /testlibrary /testlibrary/whitebox
 * @build TestHumongousCodeCacheRoots
 * @run main ClassFileInstaller sun.hotspot.WhiteBox
 * @summary Humongous objects may have references from the code cache
 * @run main TestHumongousCodeCacheRoots
*/

import com.oracle.java.testlibrary.*;
import sun.hotspot.WhiteBox;

import java.util.ArrayList;
import java.util.Arrays;

class TestHumongousCodeCacheRootsHelper {

    static final int n = 1000000;
    static final int[] AA = new int[n];
    static final int[] BB = new int[n];

    public static void main(String args[]) throws Exception {
        // do some work so that the compiler compiles this method, inlining the
        // reference to the integer array (which is a humonguous object) into
        // the code cache.
        for(int i = 0; i < n; i++) {
            AA[i] = 0;
            BB[i] = 0;
        }
        // trigger a GC that checks that the verification code allows humongous
        // objects with code cache roots; objects should be all live here.
        System.gc();

        // deoptimize everyhing: this should make all compiled code zombies.
        WhiteBox wb = WhiteBox.getWhiteBox();
        wb.deoptimizeAll();

        // trigger a GC that checks that the verification code allows humongous
        // objects with code cache roots; objects should be all live here.
        System.gc();

        // wait a little for the code cache sweeper to try to clean up zombie nmethods
        // and unregister the code roots.
        try { Thread.sleep(5000); } catch (InterruptedException ex) { }

        // do some work on the arrays to make sure that they need to be live after the GCs
        for(int i = 0; i < n; i++) {
            AA[i] = 1;
            BB[i] = 10;
        }

        System.out.println();
    }
}

public class TestHumongousCodeCacheRoots {

  /**
   * Executes a class in a new VM process with the given parameters.
   * @param vmargs Arguments to the VM to run
   * @param classname Name of the class to run
   * @param arguments Arguments to the class
   * @param useTestDotJavaDotOpts Use test.java.opts as part of the VM argument string
   * @return The OutputAnalyzer with the results for the invocation.
   */
  public static OutputAnalyzer runWhiteBoxTest(String[] vmargs, String classname, String[] arguments, boolean useTestDotJavaDotOpts) throws Exception {
    ArrayList<String> finalargs = new ArrayList();

    String[] whiteboxOpts = new String[] {
      "-Xbootclasspath/a:.",
      "-XX:+UnlockDiagnosticVMOptions", "-XX:+WhiteBoxAPI",
      "-cp", System.getProperty("java.class.path"),
    };

    if (useTestDotJavaDotOpts) {
      // System.getProperty("test.java.opts") is '' if no options is set,
      // we need to skip such a result
      String[] externalVMOpts = new String[0];
      if (System.getProperty("test.java.opts") != null && System.getProperty("test.java.opts").length() != 0) {
        externalVMOpts = System.getProperty("test.java.opts").split(" ");
      }
      finalargs.addAll(Arrays.asList(externalVMOpts));
    }

    finalargs.addAll(Arrays.asList(vmargs));
    finalargs.addAll(Arrays.asList(whiteboxOpts));
    finalargs.add(classname);
    finalargs.addAll(Arrays.asList(arguments));

    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(finalargs.toArray(new String[0]));
    OutputAnalyzer output = new OutputAnalyzer(pb.start());
    output.shouldHaveExitValue(0);

    return output;
  }

  public static void runTest(String compiler, String[] other) throws Exception {
    ArrayList<String> joined = new ArrayList();
    joined.add(compiler);
    joined.addAll(Arrays.asList(other));
    runWhiteBoxTest(joined.toArray(new String[0]), TestHumongousCodeCacheRootsHelper.class.getName(),
      new String[] {}, false);
  }

  public static void main(String[] args) throws Exception {
    final String[] baseArguments = new String[] {
      "-XX:+UseG1GC", "-XX:G1HeapRegionSize=1M", "-Xmx100M", // make sure we get a humongous region
      "-XX:+UnlockDiagnosticVMOptions",
      "-XX:InitiatingHeapOccupancyPercent=1", // strong code root marking
      "-XX:+G1VerifyHeapRegionCodeRoots", "-XX:+VerifyAfterGC", // make sure that verification is run
      "-XX:NmethodSweepFraction=1", "-XX:NmethodSweepCheckInterval=1",  // make the code cache sweep more predictable
    };
    runTest("-client", baseArguments);
    runTest("-server", baseArguments);
  }
}

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