001/*
002 *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003 *
004 *  This file is licensed to You under the Eclipse Public License (EPL);
005 *  You may not use this file except in compliance with the License. You
006 *  may obtain a copy of the License at
007 *
008 *      http://www.opensource.org/licenses/eclipse-1.0.php
009 *
010 *  See the COPYRIGHT.txt file distributed with this work for information
011 *  regarding copyright ownership.
012 */
013package org.mmtk.utility.options;
014
015import org.mmtk.vm.VM;
016
017/**
018 * Option to enable an optimization that only scans the part of the stack that has changed since the last GC.
019 */
020public final class UseShortStackScans extends org.vmutil.options.BooleanOption {
021  /**
022   * Create the option.
023   */
024  public UseShortStackScans() {
025    super(Options.set, "Use Short Stack Scans",
026          "Use optimization that only scans the part of the stack that has changed since last GC?",
027          false);
028  }
029
030  @Override
031  protected void validate() {
032    if (!VM.scanning.supportsReturnBarrier() && value) fail("Use of short stack scans only implemented on IA32 32-bit");
033  }
034}