/*
 * 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 org.graalvm.compiler.lir.phases;

import java.util.regex.Pattern;

import org.graalvm.compiler.debug.Debug;
import org.graalvm.compiler.debug.Debug.Scope;
import org.graalvm.compiler.debug.DebugCloseable;
import org.graalvm.compiler.debug.DebugMemUseTracker;
import org.graalvm.compiler.debug.DebugTimer;
import org.graalvm.compiler.lir.LIR;
import org.graalvm.compiler.lir.gen.LIRGenerationResult;
import org.graalvm.compiler.options.Option;
import org.graalvm.compiler.options.OptionType;
import org.graalvm.compiler.options.OptionValue;

import jdk.vm.ci.code.TargetDescription;

/**
 * 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
    }

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

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

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

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

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

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

    /** Lazy initialization to create pattern only when assertions are enabled. */
    static class NamePatternHolder {
        static final Pattern NAME_PATTERN = Pattern.compile("[A-Z][A-Za-z0-9]+");
    }

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

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

    public final void apply(TargetDescription target, LIRGenerationResult lirGenRes, C context) {
        apply(target, lirGenRes, context, true);
    }

    @SuppressWarnings("try")
    public final void apply(TargetDescription target, LIRGenerationResult lirGenRes, C context, boolean dumpLIR) {
        try (Scope s = Debug.scope(getName(), this)) {
            try (DebugCloseable a = timer.start(); DebugCloseable c = memUseTracker.start()) {
                run(target, lirGenRes, context);
                if (dumpLIR && Debug.isDumpEnabled(Debug.BASIC_LOG_LEVEL)) {
                    Debug.dump(Debug.BASIC_LOG_LEVEL, lirGenRes.getLIR(), "%s", getName());
                }
            }
        } catch (Throwable e) {
            throw Debug.handle(e);
        }
    }

    protected abstract void run(TargetDescription target, LIRGenerationResult lirGenRes, C context);

    public static CharSequence createName(Class<?> clazz) {
        String className = clazz.getName();
        String s = className.substring(className.lastIndexOf(".") + 1); // strip the package name
        int innerClassPos = s.indexOf('$');
        if (innerClassPos > 0) {
            /* Remove inner class name. */
            s = s.substring(0, innerClassPos);
        }
        if (s.endsWith("Phase")) {
            s = s.substring(0, s.length() - "Phase".length());
        }
        return s;
    }

    protected CharSequence createName() {
        return createName(getClass());
    }

    public final CharSequence getName() {
        CharSequence name = createName();
        assert checkName(name);
        return name;
    }
}