1 /* 2 * Copyright (c) 2014, 2015, 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 package org.graalvm.compiler.lir.dfa; 24 25 import java.util.ArrayDeque; 26 import java.util.BitSet; 27 import java.util.Collection; 28 29 import org.graalvm.compiler.core.common.cfg.AbstractBlockBase; 30 31 /** 32 * Ensures that an element is only in the worklist once. 33 * 34 */ 35 class UniqueWorkList extends ArrayDeque<AbstractBlockBase<?>> { 36 private static final long serialVersionUID = 8009554570990975712L; 37 BitSet valid; 38 39 UniqueWorkList(int size) { 40 this.valid = new BitSet(size); 41 } 42 43 @Override 44 public AbstractBlockBase<?> poll() { 45 AbstractBlockBase<?> result = super.poll(); 46 if (result != null) { 47 valid.set(result.getId(), false); 48 } 49 return result; 50 } 51 52 @Override 53 public boolean add(AbstractBlockBase<?> pred) { 54 if (!valid.get(pred.getId())) { 55 valid.set(pred.getId(), true); 56 return super.add(pred); 57 } 58 return false; 59 } 60 61 @Override 62 public boolean addAll(Collection<? extends AbstractBlockBase<?>> collection) { 63 boolean changed = false; 64 for (AbstractBlockBase<?> element : collection) { 65 if (!valid.get(element.getId())) { 66 valid.set(element.getId(), true); 67 super.add(element); 68 changed = true; 69 } 70 } 71 return changed; 72 } 73 }