/*
 * Copyright (c) 2015, 2015, 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.lir.phases;

import java.util.*;
import java.util.regex.*;

import com.oracle.graal.api.code.*;
import com.oracle.graal.compiler.common.cfg.*;
import com.oracle.graal.debug.*;
import com.oracle.graal.debug.Debug.Scope;
import com.oracle.graal.lir.*;
import com.oracle.graal.lir.gen.*;
import com.oracle.graal.options.*;

/**
 * Base class for all {@link LIR low-level} phases. Subclasses should be stateless. There will be
 * one global instance for each phase that is shared for all compilations.
 */
public abstract class LIRPhase<C> {

    public static class Options {
        // @formatter:off
        @Option(help = "Enable LIR level optimiztations.", type = OptionType.Debug)
        public static final OptionValue<Boolean> LIROptimization = new OptionValue<>(true);
        // @formatter:on
    }

    private static final int PHASE_DUMP_LEVEL = 2;

    private CharSequence name;

    /**
     * Records time spent within {@link #apply}.
     */
    private final DebugTimer timer;

    /**
     * Records memory usage within {@link #apply}.
     */
    private final DebugMemUseTracker memUseTracker;

    private static class LIRPhaseStatistics {
        /**
         * Records time spent within {@link #apply}.
         */
        private final DebugTimer timer;

        /**
         * Records memory usage within {@link #apply}.
         */
        private final DebugMemUseTracker memUseTracker;

        LIRPhaseStatistics(Class<?> clazz) {
            timer = Debug.timer("LIRPhaseTime_%s", clazz);
            memUseTracker = Debug.memUseTracker("LIRPhaseMemUse_%s", clazz);
        }
    }

    private static final ClassValue<LIRPhaseStatistics> statisticsClassValue = new ClassValue<LIRPhaseStatistics>() {
        @Override
        protected LIRPhaseStatistics computeValue(Class<?> c) {
            return new LIRPhaseStatistics(c);
        }
    };

    @SuppressWarnings("all")
    private static boolean assertionsEnabled() {
        boolean enabled = false;
        assert enabled = true;
        return enabled;
    }

    private static final Pattern NAME_PATTERN = assertionsEnabled() ? Pattern.compile("[A-Z][A-Za-z0-9]+") : null;

    private static boolean checkName(String name) {
        assert name == null || NAME_PATTERN.matcher(name).matches() : "illegal phase name: " + name;
        return true;
    }

    public LIRPhase() {
        LIRPhaseStatistics statistics = statisticsClassValue.get(getClass());
        timer = statistics.timer;
        memUseTracker = statistics.memUseTracker;
    }

    protected LIRPhase(String name) {
        assert checkName(name);
        this.name = name;
        LIRPhaseStatistics statistics = statisticsClassValue.get(getClass());
        timer = statistics.timer;
        memUseTracker = statistics.memUseTracker;
    }

    public final <B extends AbstractBlockBase<B>> void apply(TargetDescription target, LIRGenerationResult lirGenRes, List<B> codeEmittingOrder, List<B> linearScanOrder, C context) {
        apply(target, lirGenRes, codeEmittingOrder, linearScanOrder, context, true);
    }

    public final <B extends AbstractBlockBase<B>> void apply(TargetDescription target, LIRGenerationResult lirGenRes, List<B> codeEmittingOrder, List<B> linearScanOrder, C context, boolean dumpLIR) {
        try (Scope s = Debug.scope(getName(), this)) {
            try (DebugCloseable a = timer.start(); DebugCloseable c = memUseTracker.start()) {
                run(target, lirGenRes, codeEmittingOrder, linearScanOrder, context);
                if (dumpLIR && Debug.isDumpEnabled(PHASE_DUMP_LEVEL)) {
                    Debug.dump(PHASE_DUMP_LEVEL, lirGenRes.getLIR(), "After phase %s", getName());
                }
            }
        } catch (Throwable e) {
            throw Debug.handle(e);
        }
    }

    protected abstract <B extends AbstractBlockBase<B>> void run(TargetDescription target, LIRGenerationResult lirGenRes, List<B> codeEmittingOrder, List<B> linearScanOrder, C context);

    protected CharSequence createName() {
        String className = LIRPhase.this.getClass().getName();
        String s = className.substring(className.lastIndexOf(".") + 1); // strip the package name
        if (s.endsWith("Phase")) {
            s = s.substring(0, s.length() - "Phase".length());
        }
        return s;
    }

    public final CharSequence getName() {
        if (name == null) {
            name = createName();
        }
        return name;
    }

}