/*

 * Copyright (c) 2017, 2019, 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.lir.StandardOp.LoadConstantOp;

import org.graalvm.compiler.lir.StandardOp.MoveOp;

import org.graalvm.compiler.lir.StandardOp.ValueMoveOp;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.java.InstanceOfNode;

import org.graalvm.compiler.nodes.spi.CoreProviders;

import org.graalvm.compiler.phases.VerifyPhase;

import jdk.vm.ci.meta.MetaAccessProvider;

import jdk.vm.ci.meta.ResolvedJavaMethod;

import jdk.vm.ci.meta.ResolvedJavaType;

/**

 * Checks that we do not use {@code instanceof} for types where faster alternatives are available.

 */

public class VerifyInstanceOfUsage extends VerifyPhase<CoreProviders> {

    private static final Class<?>[] FORBIDDEN_INSTANCE_OF_CHECKS = {

                    MoveOp.class,

                    ValueMoveOp.class,

                    LoadConstantOp.class

    };

    @Override

    public boolean checkContract() {

        return false;

    }

    @Override

    protected void verify(StructuredGraph graph, CoreProviders context) {

        final ResolvedJavaType[] bailoutType = new ResolvedJavaType[FORBIDDEN_INSTANCE_OF_CHECKS.length];

        for (int i = 0; i < FORBIDDEN_INSTANCE_OF_CHECKS.length; i++) {

            bailoutType[i] = context.getMetaAccess().lookupJavaType(FORBIDDEN_INSTANCE_OF_CHECKS[i]);

        }

        ResolvedJavaMethod method = graph.method();

        ResolvedJavaType declaringClass = method.getDeclaringClass();

        if (!isTrustedInterface(declaringClass, context.getMetaAccess())) {

            for (InstanceOfNode io : graph.getNodes().filter(InstanceOfNode.class)) {

                ResolvedJavaType type = io.type().getType();

                for (ResolvedJavaType forbiddenType : bailoutType) {

                    if (forbiddenType.equals(type)) {

                        String name = forbiddenType.getUnqualifiedName();

                        // strip outer class

                        ResolvedJavaType enclosingType = forbiddenType.getEnclosingType();

                        if (enclosingType != null) {

                            name = name.substring(enclosingType.getUnqualifiedName().length() + "$".length());

                        }

                        throw new VerificationError("Using `op instanceof %s` is not allowed. Use `%s.is%s(op)` instead. (in %s)", name, name, name, method.format("%H.%n(%p)"));

                    }

                }

            }

        }

    }

    private static boolean isTrustedInterface(ResolvedJavaType declaringClass, MetaAccessProvider metaAccess) {

        for (Class<?> trustedCls : FORBIDDEN_INSTANCE_OF_CHECKS) {

            ResolvedJavaType trusted = metaAccess.lookupJavaType(trustedCls);

            if (trusted.equals(declaringClass)) {

                return true;

            }

        }

        return false;

    }

}