/*

 * Copyright (c) 2017, 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.core;

import static org.graalvm.compiler.core.CompilationWrapper.ExceptionAction.ExitVM;

import static org.graalvm.compiler.core.GraalCompilerOptions.CompilationBailoutAction;

import static org.graalvm.compiler.core.GraalCompilerOptions.CompilationFailureAction;

import static org.graalvm.compiler.core.GraalCompilerOptions.ExitVMOnException;

import static org.graalvm.compiler.core.GraalCompilerOptions.MaxCompilationProblemsPerAction;

import static org.graalvm.compiler.debug.DebugContext.VERBOSE_LEVEL;

import static org.graalvm.compiler.debug.DebugOptions.Dump;

import static org.graalvm.compiler.debug.DebugOptions.DumpPath;

import static org.graalvm.compiler.debug.DebugOptions.MethodFilter;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.PrintStream;

import java.util.Map;

import org.graalvm.compiler.debug.DebugContext;

import org.graalvm.compiler.debug.DiagnosticsOutputDirectory;

import org.graalvm.compiler.debug.PathUtilities;

import org.graalvm.compiler.debug.TTY;

import org.graalvm.compiler.options.EnumOptionKey;

import org.graalvm.compiler.options.OptionValues;

import jdk.vm.ci.code.BailoutException;

/**

 * Wrapper for a compilation that centralizes what action to take based on

 * {@link GraalCompilerOptions#CompilationBailoutAction} and

 * {@link GraalCompilerOptions#CompilationFailureAction} when an uncaught exception occurs during

 * compilation.

 */

public abstract class CompilationWrapper<T> {

    /**

     * Actions to take upon an exception being raised during compilation performed via

     * {@link CompilationWrapper}. The actions are with respect to what the user sees on the

     * console. The compilation requester determines what ultimate action is taken in

     * {@link CompilationWrapper#handleException(Throwable)}.

     *

     * The actions are in ascending order of verbosity.

     */

    public enum ExceptionAction {

        /**

         * Print nothing to the console.

         */

        Silent,

        /**

         * Print a stack trace to the console.

         */

        Print,

        /**

         * An exception causes the compilation to be retried with extra diagnostics enabled.

         */

        Diagnose,

        /**

         * Same as {@link #Diagnose} except that the VM process is exited after retrying.

         */

        ExitVM;

        /**

         * Gets the action that is one level less verbose than this action, bottoming out at the

         * least verbose action.

         */

        ExceptionAction quieter() {

            assert ExceptionAction.Silent.ordinal() == 0;

            int index = Math.max(ordinal() - 1, 0);

            return values()[index];

        }

    }

    private final DiagnosticsOutputDirectory outputDirectory;

    private final Map<ExceptionAction, Integer> problemsHandledPerAction;

    /**

     * @param outputDirectory object used to access a directory for dumping if the compilation is

     *            re-executed

     * @param problemsHandledPerAction map used to count the number of compilation failures or

     *            bailouts handled by each action. This is provided by the caller as it is expected

     *            to be shared between instances of {@link CompilationWrapper}.

     */

    public CompilationWrapper(DiagnosticsOutputDirectory outputDirectory, Map<ExceptionAction, Integer> problemsHandledPerAction) {

        this.outputDirectory = outputDirectory;

        this.problemsHandledPerAction = problemsHandledPerAction;

    }

    /**

     * Handles an uncaught exception.

     *

     * @param t an exception thrown during {@link #run(DebugContext)}

     * @return a value representing the result of a failed compilation (may be {@code null})

     */

    protected abstract T handleException(Throwable t);

    /**

     * Gets the action to take based on the value of {@code actionKey} in {@code options}.

     *

     * Subclasses can override this to choose a different action based on factors such as whether

     * {@code actionKey} has been explicitly set in {@code options} for example.

     *

     * @param cause the cause of the bailout or failure

     */

    protected ExceptionAction lookupAction(OptionValues options, EnumOptionKey<ExceptionAction> actionKey, Throwable cause) {

        if (actionKey == CompilationFailureAction) {

            if (ExitVMOnException.getValue(options)) {

                assert CompilationFailureAction.getDefaultValue() != ExceptionAction.ExitVM;

                assert ExitVMOnException.getDefaultValue() != true;

                if (CompilationFailureAction.hasBeenSet(options) && CompilationFailureAction.getValue(options) != ExceptionAction.ExitVM) {

                    TTY.printf("WARNING: Ignoring %s=%s since %s=true has been explicitly specified.%n",

                                    CompilationFailureAction.getName(), CompilationFailureAction.getValue(options),

                                    ExitVMOnException.getName());

                }

                return ExceptionAction.ExitVM;

            }

        }

        return actionKey.getValue(options);

    }

    /**

     * Perform the compilation wrapped by this object.

     *

     * @param debug the debug context to use for the compilation

     */

    protected abstract T performCompilation(DebugContext debug);

    /**

     * Gets a value that represents the input to the compilation.

     */

    @Override

    public abstract String toString();

    /**

     * Creates the {@link DebugContext} to use when retrying a compilation.

     *

     * @param options the options for configuring the debug context

     */

    protected abstract DebugContext createRetryDebugContext(OptionValues options);

    @SuppressWarnings("try")

    public final T run(DebugContext initialDebug) {

        try {

            return performCompilation(initialDebug);

        } catch (Throwable cause) {

            OptionValues initialOptions = initialDebug.getOptions();

            String causeType = "failure";

            EnumOptionKey<ExceptionAction> actionKey;

            if (cause instanceof BailoutException) {

                actionKey = CompilationBailoutAction;

                causeType = "bailout";

            } else {

                actionKey = CompilationFailureAction;

                causeType = "failure";

            }

            ExceptionAction action = lookupAction(initialOptions, actionKey, cause);

            action = adjustAction(initialOptions, actionKey, action);

            if (action == ExceptionAction.Silent) {

                return handleException(cause);

            }

            if (action == ExceptionAction.Print) {

                ByteArrayOutputStream baos = new ByteArrayOutputStream();

                try (PrintStream ps = new PrintStream(baos)) {

                    ps.printf("%s: Compilation of %s failed: ", Thread.currentThread(), this);

                    cause.printStackTrace(ps);

                    ps.printf("To disable compilation %s notifications, set %s to %s (e.g., -Dgraal.%s=%s).%n",

                                    causeType,

                                    actionKey.getName(), ExceptionAction.Silent,

                                    actionKey.getName(), ExceptionAction.Silent);

                    ps.printf("To capture more information for diagnosing or reporting a compilation %s, " +

                                    "set %s to %s or %s (e.g., -Dgraal.%s=%s).%n",

                                    causeType,

                                    actionKey.getName(), ExceptionAction.Diagnose,

                                    ExceptionAction.ExitVM,

                                    actionKey.getName(), ExceptionAction.Diagnose);

                }

                synchronized (CompilationFailureAction) {

                    // Synchronize to prevent compilation exception

                    // messages from interleaving.

                    TTY.println(baos.toString());

                }

                return handleException(cause);

            }

            // action is Diagnose or ExitVM

            if (Dump.hasBeenSet(initialOptions)) {

                // If dumping is explicitly enabled, Graal is being debugged

                // so don't interfere with what the user is expecting to see.

                return handleException(cause);

            }

            String dir = this.outputDirectory.getPath();

            if (dir == null) {

                return handleException(cause);

            }

            String dumpName = PathUtilities.sanitizeFileName(toString());

            File dumpPath = new File(dir, dumpName);

            dumpPath.mkdirs();

            if (!dumpPath.exists()) {

                TTY.println("Warning: could not create diagnostics directory " + dumpPath);

                return handleException(cause);

            }

            String message;

            ByteArrayOutputStream baos = new ByteArrayOutputStream();

            try (PrintStream ps = new PrintStream(baos)) {

                ps.printf("%s: Compilation of %s failed: ", Thread.currentThread(), this);

                cause.printStackTrace(ps);

                ps.printf("To disable compilation %s notifications, set %s to %s (e.g., -Dgraal.%s=%s).%n",

                                causeType,

                                actionKey.getName(), ExceptionAction.Silent,

                                actionKey.getName(), ExceptionAction.Silent);

                ps.printf("To print a message for a compilation %s without retrying the compilation, " +

                                "set %s to %s (e.g., -Dgraal.%s=%s).%n",

                                causeType,

                                actionKey.getName(), ExceptionAction.Print,

                                actionKey.getName(), ExceptionAction.Print);

                ps.println("Retrying compilation of " + this);

                message = baos.toString();

            }

            synchronized (CompilationFailureAction) {

                // Synchronize here to serialize retry compilations. This

                // mitigates retry compilation storms.

                TTY.println(message);

                File retryLogFile = new File(dumpPath, "retry.log");

                try (PrintStream ps = new PrintStream(new FileOutputStream(retryLogFile))) {

                    ps.print(message);

                } catch (IOException ioe) {

                    TTY.printf("Error writing to %s: %s%n", retryLogFile, ioe);

                }

                OptionValues retryOptions = new OptionValues(initialOptions,

                                Dump, ":" + VERBOSE_LEVEL,

                                MethodFilter, null,

                                DumpPath, dumpPath.getPath());

                try (DebugContext retryDebug = createRetryDebugContext(retryOptions)) {

                    T res = performCompilation(retryDebug);

                    maybeExitVM(action);

                    return res;

                } catch (Throwable ignore) {

                    // Failures during retry are silent

                    T res = handleException(cause);

                    maybeExitVM(action);

                    return res;

                }

            }

        }

    }

    private void maybeExitVM(ExceptionAction action) {

        if (action == ExitVM) {

            synchronized (ExceptionAction.class) {

                try {

                    // Give other compiler threads a chance to flush

                    // error handling output.

                    ExceptionAction.class.wait(2000);

                } catch (InterruptedException e) {

                }

                TTY.println("Exiting VM after retry compilation of " + this);

                System.exit(-1);

            }

        }

    }

    /**

     * Adjusts {@code initialAction} if necessary based on

     * {@link GraalCompilerOptions#MaxCompilationProblemsPerAction}.

     */

    private ExceptionAction adjustAction(OptionValues initialOptions, EnumOptionKey<ExceptionAction> actionKey, ExceptionAction initialAction) {

        ExceptionAction action = initialAction;

        int maxProblems = MaxCompilationProblemsPerAction.getValue(initialOptions);

        synchronized (problemsHandledPerAction) {

            while (action != ExceptionAction.Silent) {

                int problems = problemsHandledPerAction.getOrDefault(action, 0);

                if (problems >= maxProblems) {

                    if (problems == maxProblems) {

                        TTY.printf("Warning: adjusting %s from %s to %s after %s (%d) failed compilations%n", actionKey, action, action.quieter(),

                                        MaxCompilationProblemsPerAction, maxProblems);

                        // Ensure that the message above is only printed once

                        problemsHandledPerAction.put(action, problems + 1);

                    }

                    action = action.quieter();

                } else {

                    break;

                }

            }

            problemsHandledPerAction.put(action, problemsHandledPerAction.getOrDefault(action, 0) + 1);

        }

        return action;

    }

}