/*

 * Copyright (c) 2015, 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.core.common.type.ObjectStamp;

import org.graalvm.compiler.core.common.type.Stamp;

import org.graalvm.compiler.graph.Graph;

import org.graalvm.compiler.graph.Node;

import org.graalvm.compiler.graph.NodeInputList;

import org.graalvm.compiler.nodes.ConstantNode;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.ValueNode;

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

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

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

import org.graalvm.compiler.phases.VerifyPhase;

import jdk.vm.ci.meta.ResolvedJavaMethod;

import jdk.vm.ci.meta.ResolvedJavaType;

/**

 * Verifies that node types implementing the {@link Virtualizable} interface use it correctly.

 * Implementors of {@link Virtualizable#virtualize(org.graalvm.compiler.nodes.spi.VirtualizerTool)}

 * must not apply effects on their {@link Graph graph} that cannot be easily undone.

 */

public class VerifyVirtualizableUsage extends VerifyPhase<CoreProviders> {

    @Override

    public boolean checkContract() {

        return false;

    }

    @Override

    protected void verify(StructuredGraph graph, CoreProviders context) {

        final ResolvedJavaType graphType = context.getMetaAccess().lookupJavaType(Graph.class);

        final ResolvedJavaType virtualizableType = context.getMetaAccess().lookupJavaType(Virtualizable.class);

        final ResolvedJavaType constantNodeType = context.getMetaAccess().lookupJavaType(ConstantNode.class);

        if (virtualizableType.isAssignableFrom(graph.method().getDeclaringClass()) && graph.method().getName().equals("virtualize")) {

            for (MethodCallTargetNode t : graph.getNodes(MethodCallTargetNode.TYPE)) {

                int bci = t.invoke().bci();

                ResolvedJavaMethod callee = t.targetMethod();

                String calleeName = callee.getName();

                if (callee.getDeclaringClass().equals(graphType)) {

                    if (calleeName.equals("add") || calleeName.equals("addWithoutUnique") || calleeName.equals("addOrUnique") || calleeName.equals("addWithoutUniqueWithInputs") ||

                                    calleeName.equals("addOrUniqueWithInputs")) {

                        verifyVirtualizableEffectArguments(constantNodeType, graph.method(), callee, bci, t.arguments(), 1);

                    }

                }

            }

        }

    }

    private static void verifyVirtualizableEffectArguments(ResolvedJavaType constantNodeType, ResolvedJavaMethod caller, ResolvedJavaMethod callee, int bciCaller,

                    NodeInputList<? extends Node> arguments, int startIdx) {

        /*

         * Virtualizable.virtualize should never apply effects on the graph during the execution of

         * the call as the handling of loops during pea might be speculative and does not hold. We

         * should only allow nodes changing the graph that do no harm like constants.

         */

        int i = 0;

        for (Node arg : arguments) {

            if (i >= startIdx) {

                Stamp argStamp = ((ValueNode) arg).stamp(NodeView.DEFAULT);

                if (argStamp instanceof ObjectStamp) {

                    ObjectStamp objectStamp = (ObjectStamp) argStamp;

                    ResolvedJavaType argStampType = objectStamp.type();

                    if (!(argStampType.equals(constantNodeType))) {

                        StackTraceElement e = caller.asStackTraceElement(bciCaller);

                        throw new VerificationError("%s:Parameter %d in call to %s (which has effects on the graph) is not a " +

                                        "constant and thus not safe to apply during speculative virtualization.", e, i, callee.format("%H.%n(%p)"));

                    }

                }

            }

            i++;

        }

    }

}