/*
 * Copyright (c) 2012, 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.
 */
package com.oracle.graal.phases;

import java.util.*;

import com.oracle.graal.api.meta.*;
import com.oracle.graal.debug.*;

public final class OptimisticOptimizations {

    public static final OptimisticOptimizations ALL = new OptimisticOptimizations(EnumSet.allOf(Optimization.class));
    public static final OptimisticOptimizations NONE = new OptimisticOptimizations(EnumSet.noneOf(Optimization.class));
    private static final DebugMetric disabledOptimisticOptsMetric = Debug.metric("DisabledOptimisticOpts");

    private static enum Optimization {
        RemoveNeverExecutedCode, UseTypeCheckedInlining, UseTypeCheckHints, UseExceptionProbabilityForOperations, UseExceptionProbability
    }

    private final Set<Optimization> enabledOpts;

    public OptimisticOptimizations(ResolvedJavaMethod method) {
        this.enabledOpts = EnumSet.noneOf(Optimization.class);

        enabledOpts.add(Optimization.UseExceptionProbabilityForOperations);
        addOptimization(method, DeoptimizationReason.UnreachedCode, Optimization.RemoveNeverExecutedCode);
        addOptimization(method, DeoptimizationReason.TypeCheckedInliningViolated, Optimization.UseTypeCheckedInlining);
        addOptimization(method, DeoptimizationReason.OptimizedTypeCheckViolated, Optimization.UseTypeCheckHints);
        addOptimization(method, DeoptimizationReason.NotCompiledExceptionHandler, Optimization.UseExceptionProbability);
    }

    private void addOptimization(ResolvedJavaMethod method, DeoptimizationReason deoptReason, Optimization optimization) {
        if (checkDeoptimizations(method.getProfilingInfo(), deoptReason)) {
            enabledOpts.add(optimization);
        } else {
            /*
             * TODO (chaeubl): see GRAAL-75 (remove when we are sure that optimistic optimizations
             * are not disabled unnecessarily
             */
            disabledOptimisticOptsMetric.increment();
        }
    }

    public OptimisticOptimizations remove(Optimization... optimizations) {
        Set<Optimization> newOptimizations = EnumSet.copyOf(enabledOpts);
        for (Optimization o : optimizations) {
            newOptimizations.remove(o);
        }
        return new OptimisticOptimizations(newOptimizations);
    }

    public OptimisticOptimizations add(Optimization... optimizations) {
        Set<Optimization> newOptimizations = EnumSet.copyOf(enabledOpts);
        for (Optimization o : optimizations) {
            newOptimizations.add(o);
        }
        return new OptimisticOptimizations(newOptimizations);
    }

    private OptimisticOptimizations(Set<Optimization> enabledOpts) {
        this.enabledOpts = enabledOpts;
    }

    public boolean removeNeverExecutedCode() {
        return GraalOptions.RemoveNeverExecutedCode && enabledOpts.contains(Optimization.RemoveNeverExecutedCode);
    }

    public boolean useTypeCheckHints() {
        return GraalOptions.UseTypeCheckHints && enabledOpts.contains(Optimization.UseTypeCheckHints);
    }

    public boolean inlineMonomorphicCalls() {
        return GraalOptions.InlineMonomorphicCalls && enabledOpts.contains(Optimization.UseTypeCheckedInlining);
    }

    public boolean inlinePolymorphicCalls() {
        return GraalOptions.InlinePolymorphicCalls && enabledOpts.contains(Optimization.UseTypeCheckedInlining);
    }

    public boolean inlineMegamorphicCalls() {
        return GraalOptions.InlineMegamorphicCalls && enabledOpts.contains(Optimization.UseTypeCheckedInlining);
    }

    public boolean devirtualizeInvokes() {
        return GraalOptions.OptDevirtualizeInvokesOptimistically && enabledOpts.contains(Optimization.UseTypeCheckedInlining);
    }

    public boolean useExceptionProbability() {
        return GraalOptions.UseExceptionProbability && enabledOpts.contains(Optimization.UseExceptionProbability);
    }

    public boolean useExceptionProbabilityForOperations() {
        return GraalOptions.UseExceptionProbabilityForOperations && enabledOpts.contains(Optimization.UseExceptionProbabilityForOperations);
    }

    public boolean lessOptimisticThan(OptimisticOptimizations other) {
        for (Optimization opt : Optimization.values()) {
            if (!enabledOpts.contains(opt) && other.enabledOpts.contains(opt)) {
                return true;
            }
        }
        return false;
    }

    private static boolean checkDeoptimizations(ProfilingInfo profilingInfo, DeoptimizationReason reason) {
        return profilingInfo.getDeoptimizationCount(reason) < GraalOptions.DeoptsToDisableOptimisticOptimization;
    }
}