/*

 * Copyright (c) 2014, 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.

 */

/*

 * @test

 * @bug 8030976 8059226

 * @library /test/lib /

 * @modules java.base/jdk.internal.org.objectweb.asm

 *          java.base/jdk.internal.misc

 *          java.compiler

 *          java.management

 *          jdk.jvmstat/sun.jvmstat.monitor

 *

 * @build sun.hotspot.WhiteBox

 * @run driver ClassFileInstaller sun.hotspot.WhiteBox

 *                                sun.hotspot.WhiteBox$WhiteBoxPermission

 * @run main/othervm -Xbatch -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions

 *                   -XX:+WhiteBoxAPI -XX:+LogCompilation

 *                   -XX:CompileCommand=compileonly,UnstableIfExecutable.test

 *                   -XX:LogFile=always_taken_not_fired.xml

 *                   compiler.uncommontrap.TestUnstableIfTrap ALWAYS_TAKEN false

 * @run main/othervm -Xbatch -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions

 *                   -XX:+WhiteBoxAPI -XX:+LogCompilation

 *                   -XX:CompileCommand=compileonly,UnstableIfExecutable.test

 *                   -XX:LogFile=always_taken_fired.xml

 *                   compiler.uncommontrap.TestUnstableIfTrap ALWAYS_TAKEN true

 * @run main/othervm -Xbatch -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions

 *                   -XX:+WhiteBoxAPI -XX:+LogCompilation

 *                   -XX:CompileCommand=compileonly,UnstableIfExecutable.test

 *                   -XX:LogFile=never_taken_not_fired.xml

 *                   compiler.uncommontrap.TestUnstableIfTrap NEVER_TAKEN false

 * @run main/othervm -Xbatch -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions

 *                   -XX:+WhiteBoxAPI -XX:+LogCompilation

 *                   -XX:CompileCommand=compileonly,UnstableIfExecutable.test

 *                   -XX:LogFile=never_taken_fired.xml

 *                   compiler.uncommontrap.TestUnstableIfTrap NEVER_TAKEN true

 * @run driver compiler.testlibrary.uncommontrap.Verifier always_taken_not_fired.xml

 *                                                        always_taken_fired.xml

 *                                                        never_taken_not_fired.xml

 *                                                        never_taken_fired.xml

 */

package compiler.uncommontrap;

import compiler.testlibrary.uncommontrap.Verifier;

import jdk.internal.org.objectweb.asm.ClassVisitor;

import jdk.internal.org.objectweb.asm.ClassWriter;

import jdk.internal.org.objectweb.asm.Label;

import jdk.internal.org.objectweb.asm.MethodVisitor;

import jdk.test.lib.ByteCodeLoader;

import jdk.test.lib.Platform;

import sun.hotspot.WhiteBox;

import java.io.File;

import java.io.FileWriter;

import java.io.IOException;

import java.lang.reflect.Method;

import java.util.Properties;

import static jdk.internal.org.objectweb.asm.Opcodes.ACC_ABSTRACT;

import static jdk.internal.org.objectweb.asm.Opcodes.ACC_PUBLIC;

import static jdk.internal.org.objectweb.asm.Opcodes.ACC_STATIC;

import static jdk.internal.org.objectweb.asm.Opcodes.ACC_VOLATILE;

import static jdk.internal.org.objectweb.asm.Opcodes.GETSTATIC;

import static jdk.internal.org.objectweb.asm.Opcodes.GOTO;

import static jdk.internal.org.objectweb.asm.Opcodes.IADD;

import static jdk.internal.org.objectweb.asm.Opcodes.ICONST_1;

import static jdk.internal.org.objectweb.asm.Opcodes.IFEQ;

import static jdk.internal.org.objectweb.asm.Opcodes.ILOAD;

import static jdk.internal.org.objectweb.asm.Opcodes.ISUB;

import static jdk.internal.org.objectweb.asm.Opcodes.RETURN;

public class TestUnstableIfTrap {

    private static final WhiteBox WB = WhiteBox.getWhiteBox();

    private static final String CLASS_NAME = "UnstableIfExecutable";

    private static final String METHOD_NAME = "test";

    private static final String FIELD_NAME = "field";

    private static final int ITERATIONS = 1_000_000;

    // There is no dependency on particular class file version, so it could be

    // set to any version (if you're updating this test for Java 42).

    private static final int CLASS_FILE_VERSION = 49;

    private static final int MAX_TIER = 4;

    // This test aimed to verify that uncommon trap with reason "unstable_if"

    // is emitted when method that contain control-flow divergence such that

    // one of two branches is never taken (and other one is taken always).

    // C2 will made a decision whether or not the branch was ever taken

    // depending on method's profile.

    // If profile was collected for a few method's invocations, then C2 will not

    // trust in branches' probabilities and the tested trap won't be emitted.

    // In fact, a method has to be invoked at least 40 time at the day when this

    // comment was written (see Parse::dynamic_branch_prediction for an actual

    // value). It would be to implementation dependent to use "40" as

    // a threshold value in the test, so in order to improve test's robustness

    // the threshold value is 1000: if the tested method was compiled by C2

    // before it was invoked 1000 times, then we won't verify that trap was

    // emitted and fired.

    private static final int MIN_INVOCATIONS_BEFORE_C2_COMPILATION = 1000;

    /**

     * Description of test case parameters and uncommon trap that will

     * be emitted during tested method compilation.

     */

    private static enum TestCaseName {

        ALWAYS_TAKEN(false, "taken always"),

        NEVER_TAKEN(true, "taken never");

        TestCaseName(boolean predicate, String comment) {

            this.predicate = predicate;

            this.comment = comment;

        }

        public final boolean predicate;

        public final String name = "unstable_if";

        public final String comment;

    }

    public static void main(String args[]) {

        if (args.length != 2) {

            throw new Error("Expected two arguments: test case name and a "

                    + "boolean determining if uncommon trap should be fired.");

        }

        test(TestCaseName.valueOf(args[0]), Boolean.valueOf(args[1]));

    }

    private static void test(TestCaseName testCase, boolean shouldBeFired) {

        Method testMethod;

        Label unstableIfLocation = new Label();

        boolean shouldBeEmitted;

        boolean compiledToEarly = false;

        try {

            Class testClass = ByteCodeLoader.load(CLASS_NAME,

                    generateTest(unstableIfLocation));

            testMethod = testClass.getDeclaredMethod(METHOD_NAME,

                    boolean.class);

            for (int i = 0; i < ITERATIONS; i++) {

                testMethod.invoke(null, testCase.predicate);

                if (i < MIN_INVOCATIONS_BEFORE_C2_COMPILATION

                        && isMethodCompiledByC2(testMethod)) {

                    compiledToEarly = true;

                    // There is no sense in further invocations: we already

                    // decided to avoid verification.

                    break;

                }

            }

            // We're checking that trap should be emitted (i.e. it was compiled

            // by C2) before the trap is fired, because otherwise the nmethod

            // will be deoptimized and isMethodCompiledByC2 will return false.

            shouldBeEmitted = isMethodCompiledByC2(testMethod)

                    && !compiledToEarly;

            if (shouldBeFired) {

                testMethod.invoke(null, !testCase.predicate);

            }

        } catch (ReflectiveOperationException e) {

            throw new Error("Test case should be generated, loaded and executed"

                    + " without any issues.", e);

        }

        shouldBeFired &= shouldBeEmitted;

        Properties properties = new Properties();

        properties.setProperty(Verifier.VERIFICATION_SHOULD_BE_SKIPPED,

                Boolean.toString(compiledToEarly));

        properties.setProperty(Verifier.UNCOMMON_TRAP_SHOULD_EMITTED,

                Boolean.toString(shouldBeEmitted));

        properties.setProperty(Verifier.UNCOMMON_TRAP_SHOULD_FIRED,

                Boolean.toString(shouldBeFired));

        properties.setProperty(Verifier.UNCOMMON_TRAP_NAME, testCase.name);

        properties.setProperty(Verifier.UNCOMMON_TRAP_COMMENT,

                testCase.comment);

        properties.setProperty(Verifier.UNCOMMON_TRAP_BCI,

                Integer.toString(unstableIfLocation.getOffset()));

        properties.list(System.out);

        File f = new File(WB.getStringVMFlag("LogFile") +

                Verifier.PROPERTIES_FILE_SUFFIX);

        try (FileWriter wr = new FileWriter(f)) {

            properties.store(wr, "");

        } catch (IOException e) {

            throw new Error("Unable to store test properties.", e);

        }

    }

    private static boolean isMethodCompiledByC2(Method m) {

        boolean isTiered = WB.getBooleanVMFlag("TieredCompilation");

        boolean isMethodCompiled = WB.isMethodCompiled(m);

        boolean isMethodCompiledAtMaxTier

                = WB.getMethodCompilationLevel(m) == MAX_TIER;

        return Platform.isServer() && isMethodCompiled

                && (!isTiered || isMethodCompiledAtMaxTier);

    }

    /**

     * Generates class with name {@code CLASS_NAME}, which will contain a

     * static method {@code METHOD_NAME}:

     *

     * <pre>{@code

     * public abstract class UnstableIfExecutable {

     *   private static int field = 0;

     *

     *   public static void test(boolean alwaysTrue) {

     *     if (alwaysTrue) {

     *       field++;

     *     } else {

     *       field--;

     *     }

     *   }

     * }

     * }</pre>

     *

     * @return generated bytecode.

     */

    private static byte[] generateTest(Label unstableIfLocation) {

        ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES);

        cw.visit(CLASS_FILE_VERSION, ACC_PUBLIC | ACC_ABSTRACT, CLASS_NAME,

                null, "java/lang/Object", null);

        cw.visitField(ACC_PUBLIC | ACC_STATIC | ACC_VOLATILE, FIELD_NAME,

                "I", null, Integer.valueOf(0));

        generateTestMethod(cw, unstableIfLocation);

        return cw.toByteArray();

    }

    private static void generateTestMethod(ClassVisitor cv,

            Label unstableIfLocation) {

        MethodVisitor mv = cv.visitMethod(ACC_PUBLIC | ACC_STATIC, METHOD_NAME,

                "(Z)V", null, null);

        mv.visitCode();

        Label end = new Label();

        Label falseBranch = new Label();

        // push "field" field's value and 1 to stack

        mv.visitFieldInsn(GETSTATIC, CLASS_NAME, FIELD_NAME, "I");

        mv.visitInsn(ICONST_1);

        // load argument's value

        mv.visitVarInsn(ILOAD, 0); // alwaysTrue

        // here is our unstable if

        mv.visitLabel(unstableIfLocation);

        mv.visitJumpInsn(IFEQ, falseBranch);

        // increment on "true"

        mv.visitInsn(IADD);

        mv.visitJumpInsn(GOTO, end);

        // decrement on "false"

        mv.visitLabel(falseBranch);

        mv.visitInsn(ISUB);

        mv.visitLabel(end);

        // bye bye

        mv.visitInsn(RETURN);

        mv.visitMaxs(0, 0);

        mv.visitEnd();

    }

}