1 /* 2 * Copyright (c) 2012, 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 package jdk.vm.ci.meta; 24 25 import java.util.*; 26 import java.util.concurrent.*; 27 28 /** 29 * Manages a list of unique deoptimization reasons. 30 * 31 */ 32 public abstract class SpeculationLog { 33 private volatile Object lastFailed; 34 private volatile Collection<Object> speculations; 35 private Set<Object> failedSpeculations; 36 37 public synchronized void collectFailedSpeculations() { 38 if (lastFailed != null) { 39 if (failedSpeculations == null) { 40 failedSpeculations = new HashSet<>(2); 41 } 42 failedSpeculations.add(lastFailed); 43 lastFailed = null; 44 speculations = null; 45 } 46 } 47 48 public boolean maySpeculate(Object reason) { 49 if (failedSpeculations != null && failedSpeculations.contains(reason)) { 50 return false; 51 } 52 return true; 53 } 54 55 protected void addSpeculation(Object reason) { 56 assert maySpeculate(reason); 57 if (speculations == null) { 58 synchronized (this) { 59 if (speculations == null) { 60 speculations = new ConcurrentLinkedQueue<>(); 61 } 62 } 63 } 64 speculations.add(reason); 65 } 66 67 public abstract JavaConstant speculate(Object reason); 68 }