/*
 * Copyright (c) 2014, 2014, 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.
 *
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package jdk.vm.ci.hotspot;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import jdk.vm.ci.meta.JavaConstant;
import jdk.vm.ci.meta.SpeculationLog;

public class HotSpotSpeculationLog implements SpeculationLog {
    public static final class HotSpotSpeculation extends Speculation {
        private JavaConstant encoding;

        HotSpotSpeculation(SpeculationReason reason, JavaConstant encoding) {
            super(reason);
            this.encoding = encoding;
        }

        public JavaConstant getEncoding() {
            return encoding;
        }
    }

    
Written by the C++ code that performs deoptimization.
/** Written by the C++ code that performs deoptimization. */
private volatile long lastFailed;
All speculations that have caused a deoptimization.
/** All speculations that have caused a deoptimization. */
private Set<SpeculationReason> failedSpeculations;
Strong references to all reasons embedded in the current nmethod.
/** Strong references to all reasons embedded in the current nmethod. */
private HashMap<SpeculationReason, JavaConstant> speculations; private long currentSpeculationID; @Override public synchronized void collectFailedSpeculations() { if (lastFailed != 0) { if (failedSpeculations == null) { failedSpeculations = new HashSet<>(2); } if (speculations != null) { SpeculationReason lastFailedSpeculation = lookupSpeculation(this.lastFailed); if (lastFailedSpeculation != null) { failedSpeculations.add(lastFailedSpeculation); } lastFailed = 0; speculations = null; } } } private SpeculationReason lookupSpeculation(long value) { for (Map.Entry<SpeculationReason, JavaConstant> entry : speculations.entrySet()) { if (value == entry.getValue().asLong()) { return entry.getKey(); } } return null; } @Override public synchronized boolean maySpeculate(SpeculationReason reason) { if (failedSpeculations != null && failedSpeculations.contains(reason)) { return false; } return true; } @Override public synchronized Speculation speculate(SpeculationReason reason) { if (speculations == null) { speculations = new HashMap<>(); } JavaConstant id = speculations.get(reason); if (id == null) { id = JavaConstant.forLong(++currentSpeculationID); speculations.put(reason, id); } return new HotSpotSpeculation(reason, id); } @Override public synchronized boolean hasSpeculations() { return speculations != null && !speculations.isEmpty(); } @Override public synchronized Speculation lookupSpeculation(JavaConstant constant) { if (constant.isDefaultForKind()) { return NO_SPECULATION; } SpeculationReason reason = lookupSpeculation(constant.asLong()); assert reason != null : "Speculation should have been registered"; return new HotSpotSpeculation(reason, constant); } }