/*
 * Copyright (c) 2013, 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.
 */

import com.sun.management.HotSpotDiagnosticMXBean;
import com.sun.management.VMOption;
import sun.hotspot.WhiteBox;
import sun.management.ManagementFactoryHelper;

import java.lang.reflect.Constructor;
import java.lang.reflect.Executable;
import java.lang.reflect.Method;
import java.util.Objects;
import java.util.concurrent.Callable;

/**
 * Abstract class for WhiteBox testing of JIT.
 *
 * @author igor.ignatyev@oracle.com
 */
public abstract class CompilerWhiteBoxTest {
    /** {@code CompLevel::CompLevel_none} -- Interpreter */
    protected static int COMP_LEVEL_NONE = 0;
    /** {@code CompLevel::CompLevel_any}, {@code CompLevel::CompLevel_all} */
    protected static int COMP_LEVEL_ANY = -1;
    /** {@code CompLevel::CompLevel_simple} -- C1 */
    protected static int COMP_LEVEL_SIMPLE = 1;
    /** {@code CompLevel::CompLevel_full_optimization} -- C2 or Shark */
    protected static int COMP_LEVEL_FULL_OPTIMIZATION = 4;

    /** Instance of WhiteBox */
    protected static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();
    /** Value of {@code -XX:CompileThreshold} */
    protected static final int COMPILE_THRESHOLD
            = Integer.parseInt(getVMOption("CompileThreshold", "10000"));
    /** Value of {@code -XX:BackgroundCompilation} */
    protected static final boolean BACKGROUND_COMPILATION
            = Boolean.valueOf(getVMOption("BackgroundCompilation", "true"));
    /** Value of {@code -XX:TieredCompilation} */
    protected static final boolean TIERED_COMPILATION
            = Boolean.valueOf(getVMOption("TieredCompilation", "false"));
    /** Value of {@code -XX:TieredStopAtLevel} */
    protected static final int TIERED_STOP_AT_LEVEL
            = Integer.parseInt(getVMOption("TieredStopAtLevel", "0"));

    /**
     * Returns value of VM option.
     *
     * @param name option's name
     * @return value of option or {@code null}, if option doesn't exist
     * @throws NullPointerException if name is null
     */
    protected static String getVMOption(String name) {
        Objects.requireNonNull(name);
        HotSpotDiagnosticMXBean diagnostic
                = ManagementFactoryHelper.getDiagnosticMXBean();
        VMOption tmp;
        try {
            tmp = diagnostic.getVMOption(name);
        } catch (IllegalArgumentException e) {
            tmp = null;
        }
        return (tmp == null ? null : tmp.getValue());
    }

    /**
     * Returns value of VM option or default value.
     *
     * @param name         option's name
     * @param defaultValue default value
     * @return value of option or {@code defaultValue}, if option doesn't exist
     * @throws NullPointerException if name is null
     * @see #getVMOption(String)
     */
    protected static String getVMOption(String name, String defaultValue) {
        String result = getVMOption(name);
        return result == null ? defaultValue : result;
    }

    /** copy of is_c1_compile(int) from utilities/globalDefinitions.hpp */
    protected static boolean isC1Compile(int compLevel) {
        return (compLevel > COMP_LEVEL_NONE)
                && (compLevel < COMP_LEVEL_FULL_OPTIMIZATION);
    }

    /** copy of is_c2_compile(int) from utilities/globalDefinitions.hpp */
    protected static boolean isC2Compile(int compLevel) {
        return compLevel == COMP_LEVEL_FULL_OPTIMIZATION;
    }

    /** tested method */
    protected final Executable method;
    private final Callable<Integer> callable;

    /**
     * Constructor.
     *
     * @param testCase object, that contains tested method and way to invoke it.
     */
    protected CompilerWhiteBoxTest(TestCase testCase) {
        Objects.requireNonNull(testCase);
        System.out.println("TEST CASE:" + testCase.name());
        method = testCase.executable;
        callable = testCase.callable;
    }

    /**
     * Template method for testing. Prints tested method's info before
     * {@linkplain #test()} and after {@linkplain #test()} or on thrown
     * exception.
     *
     * @throws RuntimeException if method {@linkplain #test()} throws any
     *                          exception
     * @see #test()
     */
    protected final void runTest() {
        if (ManagementFactoryHelper.getCompilationMXBean() == null) {
            System.err.println(
                    "Warning: test is not applicable in interpreted mode");
            return;
        }
        System.out.println("at test's start:");
        printInfo();
        try {
            test();
        } catch (Exception e) {
            System.out.printf("on exception '%s':", e.getMessage());
            printInfo();
            e.printStackTrace();
            if (e instanceof RuntimeException) {
                throw (RuntimeException) e;
            }
            throw new RuntimeException(e);
        }
        System.out.println("at test's end:");
        printInfo();
    }

    /**
     * Checks, that {@linkplain #method} is not compiled.
     *
     * @throws RuntimeException if {@linkplain #method} is in compiler queue or
     *                          is compiled, or if {@linkplain #method} has zero
     *                          compilation level.
     */
    protected final void checkNotCompiled() {
        if (WHITE_BOX.isMethodQueuedForCompilation(method)) {
            throw new RuntimeException(method + " must not be in queue");
        }
        if (WHITE_BOX.isMethodCompiled(method)) {
            throw new RuntimeException(method + " must be not compiled");
        }
        if (WHITE_BOX.getMethodCompilationLevel(method) != 0) {
            throw new RuntimeException(method + " comp_level must be == 0");
        }
    }

    /**
     * Checks, that {@linkplain #method} is compiled.
     *
     * @throws RuntimeException if {@linkplain #method} isn't in compiler queue
     *                          and isn't compiled, or if {@linkplain #method}
     *                          has nonzero compilation level
     */
    protected final void checkCompiled() {
        final long start = System.currentTimeMillis();
        waitBackgroundCompilation();
        if (WHITE_BOX.isMethodQueuedForCompilation(method)) {
            System.err.printf("Warning: %s is still in queue after %dms%n",
                    method, System.currentTimeMillis() - start);
            return;
        }
        if (!WHITE_BOX.isMethodCompiled(method)) {
            throw new RuntimeException(method + " must be compiled");
        }
        if (WHITE_BOX.getMethodCompilationLevel(method) == 0) {
            throw new RuntimeException(method + " comp_level must be != 0");
        }
    }

    /**
     * Waits for completion of background compilation of {@linkplain #method}.
     */
    protected final void waitBackgroundCompilation() {
        if (!BACKGROUND_COMPILATION) {
            return;
        }
        final Object obj = new Object();
        for (int i = 0; i < 10
                && WHITE_BOX.isMethodQueuedForCompilation(method); ++i) {
            synchronized (obj) {
                try {
                    obj.wait(1000);
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                }
            }
        }
    }

    /**
     * Prints information about {@linkplain #method}.
     */
    protected final void printInfo() {
        System.out.printf("%n%s:%n", method);
        System.out.printf("\tcompilable:\t%b%n",
                WHITE_BOX.isMethodCompilable(method));
        System.out.printf("\tcompiled:\t%b%n",
                WHITE_BOX.isMethodCompiled(method));
        System.out.printf("\tcomp_level:\t%d%n",
                WHITE_BOX.getMethodCompilationLevel(method));
        System.out.printf("\tin_queue:\t%b%n",
                WHITE_BOX.isMethodQueuedForCompilation(method));
        System.out.printf("compile_queues_size:\t%d%n%n",
                WHITE_BOX.getCompileQueuesSize());
    }

    /**
     * Executes testing.
     */
    protected abstract void test() throws Exception;

    /**
     * Tries to trigger compilation of {@linkplain #method} by call
     * {@linkplain #callable} enough times.
     *
     * @return accumulated result
     * @see #compile(int)
     */
    protected final int compile() {
        return compile(Math.max(COMPILE_THRESHOLD, 150000));
    }

    /**
     * Tries to trigger compilation of {@linkplain #method} by call
     * {@linkplain #callable} specified times.
     *
     * @param count invocation count
     * @return accumulated result
     */
    protected final int compile(int count) {
        int result = 0;
        Integer tmp;
        for (int i = 0; i < count; ++i) {
            try {
                tmp = callable.call();
            } catch (Exception e) {
                tmp = null;
            }
            result += tmp == null ? 0 : tmp;
        }
        System.out.println("method was invoked " + count + " times");
        return result;
    }
}

/**
 * Utility structure containing tested method and object to invoke it.
 */
enum TestCase {
    /** constructor test case */
    CONSTRUCTOR_TEST(Helper.CONSTRUCTOR, Helper.CONSTRUCTOR_CALLABLE),
    /** method test case */
    METOD_TEST(Helper.METHOD, Helper.METHOD_CALLABLE),
    /** static method test case */
    STATIC_TEST(Helper.STATIC, Helper.STATIC_CALLABLE);

    /** tested method */
    final Executable executable;
    /** object to invoke {@linkplain #executable} */
    final Callable<Integer> callable;

    private TestCase(Executable executable, Callable<Integer> callable) {
        this.executable = executable;
        this.callable = callable;
    }

    private static class Helper {
        private static final Callable<Integer> CONSTRUCTOR_CALLABLE
                = new Callable<Integer>() {
            @Override
            public Integer call() throws Exception {
                return new Helper(1337).hashCode();
            }
        };

        private static final Callable<Integer> METHOD_CALLABLE
                = new Callable<Integer>() {
            private final Helper helper = new Helper();

            @Override
            public Integer call() throws Exception {
                return helper.method();
            }
        };

        private static final Callable<Integer> STATIC_CALLABLE
                = new Callable<Integer>() {
            @Override
            public Integer call() throws Exception {
                return staticMethod();
            }
        };

        private static final Constructor CONSTRUCTOR;
        private static final Method METHOD;
        private static final Method STATIC;

        static {
            try {
                CONSTRUCTOR = Helper.class.getDeclaredConstructor(int.class);
            } catch (NoSuchMethodException | SecurityException e) {
                throw new RuntimeException(
                        "exception on getting method Helper.<init>(int)", e);
            }
            try {
                METHOD = Helper.class.getDeclaredMethod("method");
            } catch (NoSuchMethodException | SecurityException e) {
                throw new RuntimeException(
                        "exception on getting method Helper.method()", e);
            }
            try {
                STATIC = Helper.class.getDeclaredMethod("staticMethod");
            } catch (NoSuchMethodException | SecurityException e) {
                throw new RuntimeException(
                        "exception on getting method Helper.staticMethod()", e);
            }
        }

        private static int staticMethod() {
            return 1138;
        }

        private int method() {
            return 42;
        }

        private final int x;

        public Helper() {
            x = 0;
        }

        private Helper(int x) {
            this.x = x;
        }

        @Override
        public int hashCode() {
            return x;
        }
    }
}