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Java example source code file (Compiler.java)

This example Java source code file (Compiler.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

atomiclong, class_count, classes_limit_reached, compilemethodcommand, compiler, constantpool, executable, interruptedexception, object, override, reflection, string, stringbuilder, threading, threads, throwable, util, whitebox

The Compiler.java Java example source code

/*
 * 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.
 */

package sun.hotspot.tools.ctw;

import sun.hotspot.WhiteBox;
import sun.misc.SharedSecrets;
import sun.reflect.ConstantPool;

import java.lang.reflect.Executable;

import java.util.Objects;
import java.util.concurrent.Executor;
import java.util.concurrent.atomic.AtomicLong;

/**
 * Provide method to compile whole class.
 * Also contains compiled methods and classes counters.
 */
public class Compiler {
    private Compiler() { }
    private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();
    private static final AtomicLong CLASS_COUNT = new AtomicLong(0L);
    private static final AtomicLong METHOD_COUNT = new AtomicLong(0L);
    private static volatile boolean CLASSES_LIMIT_REACHED = false;

    /**
     * @return count of processed classes
     */
    public static long getClassCount() {
        return CLASS_COUNT.get();
    }

    /**
     * @return count of processed methods
     */
    public static long getMethodCount() {
        return METHOD_COUNT.get();
    }

    /**
     * @return {@code true} if classes limit is reached
     */
    public static boolean isLimitReached() {
        return CLASSES_LIMIT_REACHED;
    }

    /**
     * Compiles all methods and constructors.
     *
     * @param aClass class to compile
     * @param executor executor used for compile task invocation
     * @throws NullPointerException if {@code class} or {@code executor}
     *                              is {@code null}
     */
    public static void compileClass(Class aClass, Executor executor) {
        Objects.requireNonNull(aClass);
        Objects.requireNonNull(executor);
        long id = CLASS_COUNT.incrementAndGet();
        if (id > Utils.COMPILE_THE_WORLD_STOP_AT) {
            CLASS_COUNT.decrementAndGet();
            CLASSES_LIMIT_REACHED = true;
            return;
        }

        if (id >= Utils.COMPILE_THE_WORLD_START_AT) {
            String name = aClass.getName();
            try {
                System.out.printf("[%d]\t%s%n", id, name);
                ConstantPool constantPool = SharedSecrets.getJavaLangAccess().
                        getConstantPool(aClass);
                if (Utils.COMPILE_THE_WORLD_PRELOAD_CLASSES) {
                    preloadClasses(name, id, constantPool);
                }
                long methodCount = 0;
                for (Executable e : aClass.getDeclaredConstructors()) {
                    ++methodCount;
                    executor.execute(new CompileMethodCommand(id, name, e));
                }
                for (Executable e : aClass.getDeclaredMethods()) {
                    ++methodCount;
                    executor.execute(new CompileMethodCommand(id, name, e));
                }
                METHOD_COUNT.addAndGet(methodCount);

                if (Utils.DEOPTIMIZE_ALL_CLASSES_RATE > 0
                        && (id % Utils.DEOPTIMIZE_ALL_CLASSES_RATE == 0)) {
                    WHITE_BOX.deoptimizeAll();
                }
            } catch (Throwable t) {
                System.out.printf("[%d]\t%s\tskipping %s%n", id, name, t);
                t.printStackTrace();
            }
        }
    }

    private static void preloadClasses(String className, long id,
            ConstantPool constantPool) {
        try {
            for (int i = 0, n = constantPool.getSize(); i < n; ++i) {
                try {
                    constantPool.getClassAt(i);
                } catch (IllegalArgumentException ignore) {
                }
            }
        } catch (Throwable t) {
            System.out.printf("[%d]\t%s\tpreloading failed : %s%n", id,
                    className, t);
        }
    }



    /**
     * Compilation of method.
     * Will compile method on all available comp levels.
     */
    private static class CompileMethodCommand implements Runnable {
        private final long classId;
        private final String className;
        private final Executable method;

        /**
         * @param classId   id of class
         * @param className name of class
         * @param method    compiled for compilation
         */
        public CompileMethodCommand(long classId, String className,
                Executable method) {
            this.classId = classId;
            this.className = className;
            this.method = method;
        }

        @Override
        public final void run() {
            int compLevel = Utils.INITIAL_COMP_LEVEL;
            if (Utils.TIERED_COMPILATION) {
                for (int i = compLevel; i <= Utils.TIERED_STOP_AT_LEVEL; ++i) {
                    WHITE_BOX.deoptimizeMethod(method);
                    compileMethod(method, i);
                }
            } else {
                compileMethod(method, compLevel);
            }
        }

        private void waitCompilation() {
            if (!Utils.BACKGROUND_COMPILATION) {
                return;
            }
            final Object obj = new Object();
            synchronized (obj) {
                for (int i = 0;
                     i < 10 && WHITE_BOX.isMethodQueuedForCompilation(method);
                     ++i) {
                    try {
                        obj.wait(1000);
                    } catch (InterruptedException e) {
                        Thread.currentThread().interrupt();
                    }
                }
            }
        }

        private void compileMethod(Executable method, int compLevel) {
            if (WHITE_BOX.isMethodCompilable(method, compLevel)) {
                try {
                    WHITE_BOX.enqueueMethodForCompilation(method, compLevel);
                    waitCompilation();
                    int tmp = WHITE_BOX.getMethodCompilationLevel(method);
                    if (tmp != compLevel) {
                        logMethod(method, "compilation level = " + tmp
                                + ", but not " + compLevel);
                    } else if (Utils.IS_VERBOSE) {
                        logMethod(method, "compilation level = " + tmp + ". OK");
                    }
                } catch (Throwable t) {
                    logMethod(method, "error on compile at " + compLevel
                            + " level");
                    t.printStackTrace();
                }
            } else if (Utils.IS_VERBOSE) {
                logMethod(method, "not compilable at " + compLevel);
            }
        }

        private void logMethod(Executable method, String message) {
            StringBuilder builder = new StringBuilder("[");
            builder.append(classId);
            builder.append("]\t");
            builder.append(className);
            builder.append("::");
            builder.append(method.getName());
            builder.append('(');
            Class[] params = method.getParameterTypes();
            for (int i = 0, n = params.length - 1; i < n; ++i) {
                builder.append(params[i].getName());
                builder.append(", ");
            }
            if (params.length != 0) {
                builder.append(params[params.length - 1].getName());
            }
            builder.append(')');
            if (message != null) {
                builder.append('\t');
                builder.append(message);
            }
            System.err.println(builder);
        }
    }

}

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