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 * 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 com.oracle.graal.virtual.phases.ea;

import static com.oracle.graal.debug.Debug.*;
import static com.oracle.graal.phases.common.DeadCodeEliminationPhase.Optionality.*;

import java.util.*;

import com.oracle.graal.debug.*;
import com.oracle.graal.debug.Debug.Scope;
import com.oracle.graal.graph.Graph.NodeEventScope;
import com.oracle.graal.graph.*;
import com.oracle.graal.graph.spi.*;
import com.oracle.graal.nodes.*;
import com.oracle.graal.nodes.cfg.*;
import com.oracle.graal.phases.*;
import com.oracle.graal.phases.common.*;
import com.oracle.graal.phases.common.util.*;
import com.oracle.graal.phases.graph.*;
import com.oracle.graal.phases.schedule.*;
import com.oracle.graal.phases.tiers.*;

public abstract class EffectsPhase<PhaseContextT extends PhaseContext> extends BasePhase<PhaseContextT> {

    public abstract static class Closure<T> extends ReentrantBlockIterator.BlockIteratorClosure<T> {

        public abstract boolean hasChanged();

        public abstract void applyEffects();
    }

    private final int maxIterations;
    protected final CanonicalizerPhase canonicalizer;
    private final boolean unscheduled;

    protected EffectsPhase(int maxIterations, CanonicalizerPhase canonicalizer) {
        this(maxIterations, canonicalizer, false);
    }

    protected EffectsPhase(int maxIterations, CanonicalizerPhase canonicalizer, boolean unscheduled) {
        this.maxIterations = maxIterations;
        this.canonicalizer = canonicalizer;
        this.unscheduled = unscheduled;
    }

    @Override
    protected void run(StructuredGraph graph, PhaseContextT context) {
        runAnalysis(graph, context);
    }

    public boolean runAnalysis(final StructuredGraph graph, final PhaseContextT context) {
        boolean changed = false;
        for (int iteration = 0; iteration < maxIterations; iteration++) {
            try (Scope s = Debug.scope(isEnabled() ? "iteration " + iteration : null)) {
                SchedulePhase schedule;
                ControlFlowGraph cfg;
                if (unscheduled) {
                    schedule = null;
                    cfg = ControlFlowGraph.compute(graph, true, true, false, false);
                } else {
                    schedule = new SchedulePhase(SchedulePhase.SchedulingStrategy.LATEST);
                    schedule.apply(graph, false);
                    cfg = schedule.getCFG();
                }

                Closure<?> closure = createEffectsClosure(context, schedule, cfg);
                ReentrantBlockIterator.apply(closure, cfg.getStartBlock());

                if (!closure.hasChanged()) {
                    break;
                }

                // apply the effects collected during this iteration
                HashSetNodeEventListener listener = new HashSetNodeEventListener();
                try (NodeEventScope nes = graph.trackNodeEvents(listener)) {
                    closure.applyEffects();
                }

                if (Debug.isDumpEnabled()) {
                    Debug.dump(graph, "after " + getName() + " iteration");
                }

                new DeadCodeEliminationPhase(Optional).apply(graph);

                Set<Node> changedNodes = listener.getNodes();
                for (Node node : graph.getNodes()) {
                    if (node instanceof Simplifiable) {
                        changedNodes.add(node);
                    }
                }
                postIteration(graph, context, changedNodes);
            }
            changed = true;
        }
        return changed;
    }

    protected void postIteration(final StructuredGraph graph, final PhaseContextT context, Set<Node> changedNodes) {
        if (canonicalizer != null) {
            canonicalizer.applyIncremental(graph, context, changedNodes);
        }
    }

    protected abstract Closure<?> createEffectsClosure(PhaseContextT context, SchedulePhase schedule, ControlFlowGraph cfg);
}