/*

 * Copyright (c) 2016, 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.hotspot;

import static org.graalvm.compiler.hotspot.HotSpotGraalCompiler.fmt;

import static org.graalvm.compiler.hotspot.HotSpotGraalCompiler.str;

import java.util.Comparator;

import java.util.HashMap;

import java.util.Map;

import java.util.Map.Entry;

import java.util.SortedSet;

import java.util.TreeSet;

import org.graalvm.compiler.debug.TTY;

import org.graalvm.compiler.options.Option;

import org.graalvm.compiler.options.OptionType;

import org.graalvm.compiler.options.OptionValues;

import org.graalvm.compiler.options.OptionKey;

import jdk.vm.ci.code.CompilationRequest;

import jdk.vm.ci.meta.ResolvedJavaMethod;

class CompilationCounters {

    public static class Options {

        // @formatter:off

        @Option(help = "The number of compilations allowed for any method before " +

                       "the VM exits (a value of 0 means there is no limit).", type = OptionType.Debug)

        public static final OptionKey<Integer> CompilationCountLimit = new OptionKey<>(0);

        // @formatter:on

    }

    private final OptionValues options;

    CompilationCounters(OptionValues options) {

        TTY.println("Warning: Compilation counters enabled, excessive recompilation of a method will cause a failure!");

        this.options = options;

    }

    private final Map<ResolvedJavaMethod, Integer> counters = new HashMap<>();

    /**

     * Counts the number of compilations for the {@link ResolvedJavaMethod} of the

     * {@link CompilationRequest}. If the number of compilations exceeds

     * {@link Options#CompilationCountLimit} this method prints an error message and exits the VM.

     *

     * @param method the method about to be compiled

     */

    synchronized void countCompilation(ResolvedJavaMethod method) {

        Integer val = counters.get(method);

        val = val != null ? val + 1 : 1;

        counters.put(method, val);

        if (val > Options.CompilationCountLimit.getValue(options)) {

            TTY.printf("Error. Method %s was compiled too many times. Number of compilations: %d\n", fmt(method),

                            CompilationCounters.Options.CompilationCountLimit.getValue(options));

            TTY.println("==================================== High compilation counters ====================================");

            SortedSet<Map.Entry<ResolvedJavaMethod, Integer>> sortedCounters = new TreeSet<>(new CounterComparator());

            for (Map.Entry<ResolvedJavaMethod, Integer> e : counters.entrySet()) {

                sortedCounters.add(e);

            }

            for (Map.Entry<ResolvedJavaMethod, Integer> entry : sortedCounters) {

                if (entry.getValue() >= Options.CompilationCountLimit.getValue(options) / 2) {

                    TTY.out.printf("%d\t%s%n", entry.getValue(), str(entry.getKey()));

                }

            }

            TTY.flush();

            System.exit(-1);

        }

    }

    static final class CounterComparator implements Comparator<Map.Entry<ResolvedJavaMethod, Integer>> {

        @Override

        public int compare(Entry<ResolvedJavaMethod, Integer> o1, Entry<ResolvedJavaMethod, Integer> o2) {

            if (o1.getValue() < o2.getValue()) {

                return -1;

            }

            if (o1.getValue() > o2.getValue()) {

                return 1;

            }

            return str(o1.getKey()).compareTo(str(o2.getKey()));

        }

    }

}