/*

 * Copyright (c) 2015, 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.core.test;

import org.graalvm.compiler.java.GraphBuilderPhase;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderConfiguration;

import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderConfiguration.Plugins;

import org.graalvm.compiler.nodes.graphbuilderconf.InvocationPlugins;

import org.graalvm.compiler.options.OptionValues;

import org.graalvm.compiler.phases.OptimisticOptimizations;

import org.junit.Test;

import org.objectweb.asm.ClassWriter;

import org.objectweb.asm.Label;

import org.objectweb.asm.MethodVisitor;

import org.objectweb.asm.Opcodes;

import jdk.vm.ci.code.BailoutException;

import jdk.vm.ci.meta.ResolvedJavaMethod;

/**

 * Exercise handling of unbalanced monitor operations by the parser. Algorithmically Graal assumes

 * that locks are statically block structured but that isn't something enforced by the bytecodes. In

 * HotSpot a dataflow is performed to ensure they are properly structured and methods with

 * unstructured locking aren't compiled and fall back to the interpreter. Having the Graal parser

 * handle this directly is simplifying for targets of Graal since they don't have to provide a data

 * flow that checks this property.

 */

public class UnbalancedMonitorsTest extends GraalCompilerTest {

    private static final String CLASS_NAME = UnbalancedMonitorsTest.class.getName();

    private static final String INNER_CLASS_NAME = CLASS_NAME + "$UnbalancedMonitors";

    private static final String CLASS_NAME_INTERNAL = CLASS_NAME.replace('.', '/');

    private static final String INNER_CLASS_NAME_INTERNAL = INNER_CLASS_NAME.replace('.', '/');

    public UnbalancedMonitorsTest() {

        exportPackage(JAVA_BASE, "jdk.internal.org.objectweb.asm");

    }

    private static AsmLoader LOADER = new AsmLoader(UnbalancedMonitorsTest.class.getClassLoader());

    @Test

    public void runWrongOrder() throws Exception {

        checkForBailout("wrongOrder");

    }

    @Test

    public void runTooFewExits() throws Exception {

        checkForBailout("tooFewExits");

    }

    @Test

    public void runTooManyExits() throws Exception {

        checkForBailout("tooManyExits");

    }

    @Test

    public void runTooFewExitsExceptional() throws Exception {

        checkForBailout("tooFewExitsExceptional");

    }

    @Test

    public void runTooManyExitsExceptional() throws Exception {

        checkForBailout("tooManyExitsExceptional");

    }

    private void checkForBailout(String name) throws ClassNotFoundException {

        ResolvedJavaMethod method = getResolvedJavaMethod(LOADER.findClass(INNER_CLASS_NAME), name);

        try {

            OptionValues options = getInitialOptions();

            StructuredGraph graph = new StructuredGraph.Builder(options, getDebugContext(options)).method(method).build();

            Plugins plugins = new Plugins(new InvocationPlugins());

            GraphBuilderConfiguration graphBuilderConfig = GraphBuilderConfiguration.getDefault(plugins).withEagerResolving(true);

            OptimisticOptimizations optimisticOpts = OptimisticOptimizations.NONE;

            GraphBuilderPhase.Instance graphBuilder = new GraphBuilderPhase.Instance(getMetaAccess(), getProviders().getStampProvider(), null, null, graphBuilderConfig, optimisticOpts, null);

            graphBuilder.apply(graph);

        } catch (BailoutException e) {

            if (e.getMessage().contains("unbalanced monitors")) {

                return;

            }

            throw e;

        }

        assertTrue("should have bailed out", false);

    }

    static class Gen implements Opcodes {

    // @formatter:off

    // Template class used with Bytecode Outline to generate ASM code

    //    public static class UnbalancedMonitors {

    //

    //        public UnbalancedMonitors() {

    //        }

    //

    //        public Object wrongOrder(Object a, Object b) {

    //            synchronized (a) {

    //                synchronized (b) {

    //                    return b;

    //                }

    //            }

    //        }

    //

    //        public Object tooFewExits(Object a, Object b) {

    //            synchronized (a) {

    //                synchronized (b) {

    //                    return b;

    //                }

    //            }

    //        }

    //

    //        public boolean tooFewExitsExceptional(Object a, Object b) {

    //            synchronized (a) {

    //                synchronized (b) {

    //                    return b.equals(a);

    //                }

    //            }

    //        }

    //    }

    // @formatter:on

        public static byte[] generateClass() {

            ClassWriter cw = new ClassWriter(0);

            cw.visit(52, ACC_SUPER | ACC_PUBLIC, INNER_CLASS_NAME_INTERNAL, null, "java/lang/Object", null);

            cw.visitSource("UnbalancedMonitorsTest.java", null);

            cw.visitInnerClass(INNER_CLASS_NAME_INTERNAL, CLASS_NAME_INTERNAL, "UnbalancedMonitors", ACC_STATIC);

            visitConstructor(cw);

            visitWrongOrder(cw);

            visitBlockStructured(cw, true, false);

            visitBlockStructured(cw, true, true);

            visitBlockStructured(cw, false, false);

            visitBlockStructured(cw, false, true);

            cw.visitEnd();

            return cw.toByteArray();

        }

        private static void visitBlockStructured(ClassWriter cw, boolean normalReturnError, boolean tooMany) {

            String name = (tooMany ? "tooMany" : "tooFew") + "Exits" + (normalReturnError ? "" : "Exceptional");

            // Generate too many or too few exits down the either the normal or exceptional return

            // paths

            int exceptionalExitCount = normalReturnError ? 1 : (tooMany ? 2 : 0);

            int normalExitCount = normalReturnError ? (tooMany ? 2 : 0) : 1;

            MethodVisitor mv;

            mv = cw.visitMethod(ACC_PUBLIC, name, "(Ljava/lang/Object;Ljava/lang/Object;)Z", null, null);

            mv.visitCode();

            Label l0 = new Label();

            Label l1 = new Label();

            Label l2 = new Label();

            mv.visitTryCatchBlock(l0, l1, l2, null);

            Label l3 = new Label();

            mv.visitTryCatchBlock(l2, l3, l2, null);

            Label l4 = new Label();

            Label l5 = new Label();

            Label l6 = new Label();

            mv.visitTryCatchBlock(l4, l5, l6, null);

            Label l7 = new Label();

            mv.visitTryCatchBlock(l2, l7, l6, null);

            Label l8 = new Label();

            mv.visitLabel(l8);

            mv.visitVarInsn(ALOAD, 1);

            mv.visitInsn(DUP);

            mv.visitVarInsn(ASTORE, 3);

            mv.visitInsn(MONITORENTER);

            mv.visitLabel(l4);

            mv.visitVarInsn(ALOAD, 2);

            mv.visitInsn(DUP);

            mv.visitVarInsn(ASTORE, 4);

            mv.visitInsn(MONITORENTER);

            mv.visitLabel(l0);

            mv.visitVarInsn(ALOAD, 2);

            mv.visitVarInsn(ALOAD, 1);

            mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "equals", "(Ljava/lang/Object;)Z", false);

            mv.visitVarInsn(ALOAD, 4);

            mv.visitInsn(MONITOREXIT);

            mv.visitLabel(l1);

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

                mv.visitVarInsn(ALOAD, 3);

                mv.visitInsn(MONITOREXIT);

            }

            mv.visitLabel(l5);

            mv.visitInsn(IRETURN);

            mv.visitLabel(l2);

            mv.visitFrame(Opcodes.F_FULL, 5, new Object[]{INNER_CLASS_NAME_INTERNAL, "java/lang/Object", "java/lang/Object", "java/lang/Object",

                            "java/lang/Object"}, 1, new Object[]{"java/lang/Throwable"});

            mv.visitVarInsn(ALOAD, 4);

            mv.visitInsn(MONITOREXIT);

            mv.visitLabel(l3);

            mv.visitInsn(ATHROW);

            mv.visitLabel(l6);

            mv.visitFrame(Opcodes.F_FULL, 4, new Object[]{INNER_CLASS_NAME_INTERNAL, "java/lang/Object", "java/lang/Object", "java/lang/Object"}, 1,

                            new Object[]{"java/lang/Throwable"});

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

                mv.visitVarInsn(ALOAD, 3);

                mv.visitInsn(MONITOREXIT);

            }

            mv.visitLabel(l7);

            mv.visitInsn(ATHROW);

            Label l9 = new Label();

            mv.visitLabel(l9);

            mv.visitMaxs(2, 5);

            mv.visitEnd();

        }

        private static void visitWrongOrder(ClassWriter cw) {

            MethodVisitor mv;

            mv = cw.visitMethod(ACC_PUBLIC, "wrongOrder", "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;", null, null);

            mv.visitCode();

            Label l0 = new Label();

            Label l1 = new Label();

            Label l2 = new Label();

            mv.visitTryCatchBlock(l0, l1, l2, null);

            Label l3 = new Label();

            mv.visitTryCatchBlock(l2, l3, l2, null);

            Label l4 = new Label();

            Label l5 = new Label();

            Label l6 = new Label();

            mv.visitTryCatchBlock(l4, l5, l6, null);

            Label l7 = new Label();

            mv.visitTryCatchBlock(l2, l7, l6, null);

            Label l8 = new Label();

            mv.visitLabel(l8);

            mv.visitVarInsn(ALOAD, 1);

            mv.visitInsn(DUP);

            mv.visitVarInsn(ASTORE, 3);

            mv.visitInsn(MONITORENTER);

            mv.visitLabel(l4);

            mv.visitVarInsn(ALOAD, 2);

            mv.visitInsn(DUP);

            mv.visitVarInsn(ASTORE, 4);

            mv.visitInsn(MONITORENTER);

            mv.visitLabel(l0);

            mv.visitVarInsn(ALOAD, 2);

            mv.visitVarInsn(ALOAD, 3);

            mv.visitInsn(MONITOREXIT);

            mv.visitLabel(l1);

            // Swapped exit order with exit above

            mv.visitVarInsn(ALOAD, 4);

            mv.visitInsn(MONITOREXIT);

            mv.visitLabel(l5);

            mv.visitInsn(ARETURN);

            mv.visitLabel(l2);

            mv.visitFrame(Opcodes.F_FULL, 5, new Object[]{INNER_CLASS_NAME_INTERNAL, "java/lang/Object", "java/lang/Object", "java/lang/Object",

                            "java/lang/Object"}, 1, new Object[]{"java/lang/Throwable"});

            mv.visitVarInsn(ALOAD, 4);

            mv.visitInsn(MONITOREXIT);

            mv.visitLabel(l3);

            mv.visitInsn(ATHROW);

            mv.visitLabel(l6);

            mv.visitFrame(Opcodes.F_FULL, 4, new Object[]{INNER_CLASS_NAME_INTERNAL, "java/lang/Object", "java/lang/Object", "java/lang/Object"}, 1,

                            new Object[]{"java/lang/Throwable"});

            mv.visitVarInsn(ALOAD, 3);

            mv.visitInsn(MONITOREXIT);

            mv.visitLabel(l7);

            mv.visitInsn(ATHROW);

            Label l9 = new Label();

            mv.visitLabel(l9);

            mv.visitMaxs(2, 5);

            mv.visitEnd();

        }

        private static void visitConstructor(ClassWriter cw) {

            MethodVisitor mv;

            mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);

            mv.visitCode();

            Label l0 = new Label();

            mv.visitLabel(l0);

            mv.visitVarInsn(ALOAD, 0);

            mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);

            Label l1 = new Label();

            mv.visitLabel(l1);

            mv.visitInsn(RETURN);

            Label l2 = new Label();

            mv.visitLabel(l2);

            mv.visitMaxs(1, 1);

            mv.visitEnd();

        }

    }

    public static class AsmLoader extends ClassLoader {

        Class<?> loaded;

        public AsmLoader(ClassLoader parent) {

            super(parent);

        }

        @Override

        protected Class<?> findClass(String name) throws ClassNotFoundException {

            if (name.equals(INNER_CLASS_NAME)) {

                if (loaded != null) {

                    return loaded;

                }

                byte[] bytes = Gen.generateClass();

                return (loaded = defineClass(name, bytes, 0, bytes.length));

            } else {

                return super.findClass(name);

            }

        }

    }

}