/*

 * Copyright (c) 2013, 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 java.util.List;

import org.graalvm.compiler.graph.Node;

import org.graalvm.compiler.graph.Node.Input;

import org.graalvm.compiler.graph.Node.OptionalInput;

import org.graalvm.compiler.graph.NodeInputList;

import org.graalvm.compiler.nodes.StructuredGraph;

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

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

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

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

import org.graalvm.compiler.phases.VerifyPhase;

import jdk.vm.ci.meta.ResolvedJavaField;

import jdk.vm.ci.meta.ResolvedJavaMethod;

import jdk.vm.ci.meta.ResolvedJavaType;

/**

 * Try to ensure that methods which update {@link Input} or {@link OptionalInput} fields also

 * include a call to {@link Node#updateUsages} or {@link Node#updateUsagesInterface}.

 */

public class VerifyUpdateUsages extends VerifyPhase<CoreProviders> {

    @Override

    public boolean checkContract() {

        return false;

    }

    public VerifyUpdateUsages() {

    }

    @Override

    protected void verify(StructuredGraph graph, CoreProviders context) {

        if (graph.method().isConstructor()) {

            return;

        }

        /*

         * There are only two acceptable patterns for methods which update Node inputs, either a

         * single StoreField node and invoke of updateUsages or updateUsagesInterface, or 2

         * StoreFields that come from LoadFields on the same object. Other patterns can be added as

         * needed but it would be best to keep things simple so that verification can be simple.

         */

        List<StoreFieldNode> stores = graph.getNodes().filter(StoreFieldNode.class).snapshot();

        ResolvedJavaType declaringClass = graph.method().getDeclaringClass();

        ResolvedJavaType nodeInputList = context.getMetaAccess().lookupJavaType(NodeInputList.class);

        StoreFieldNode storeField1 = null;

        StoreFieldNode storeField2 = null;

        for (StoreFieldNode store : stores) {

            if (isNodeInput(store.field(), declaringClass, nodeInputList)) {

                if (storeField1 == null) {

                    storeField1 = store;

                } else if (storeField2 == null) {

                    storeField2 = store;

                } else {

                    throw new VerificationError("More than 2 stores to %s or %s fields found in %s",

                                    Input.class.getSimpleName(),

                                    OptionalInput.class.getSimpleName(),

                                    graph.method().format("%H.%n(%p)"));

                }

            }

        }

        if (storeField1 == null) {

            return;

        }

        if (storeField2 == null) {

            // Single input field update so just check for updateUsages

            // or updateUsagesInterface call

            ResolvedJavaType nodeType = context.getMetaAccess().lookupJavaType(Node.class);

            for (MethodCallTargetNode call : graph.getNodes().filter(MethodCallTargetNode.class)) {

                ResolvedJavaMethod callee = call.targetMethod();

                if (callee.getDeclaringClass().equals(nodeType) && (callee.getName().equals("updateUsages") || callee.getName().equals("updateUsagesInterface"))) {

                    return;

                }

            }

            throw new VerificationError("%s updates field '%s' without calling %s.updateUsages() or %s.updateUsagesInterface()",

                            graph.method().format("%H.%n(%p)"),

                            storeField1.field().getName(),

                            Node.class.getName(),

                            Node.class.getName());

        } else {

            if (storeField1.value() instanceof LoadFieldNode && storeField2.value() instanceof LoadFieldNode) {

                LoadFieldNode load1 = (LoadFieldNode) storeField1.value();

                LoadFieldNode load2 = (LoadFieldNode) storeField2.value();

                // Check for swapping values within the same object

                if (load1.object() == storeField1.object() &&

                                load2.object() == storeField2.object() &&

                                storeField1.object() == storeField2.object() &&

                                load1.field().equals(storeField2.field()) &&

                                load2.field().equals(storeField1.field())) {

                    return;

                }

            }

            throw new VerificationError("%s performs non-swap update to fields '%s' and '%s' without calling %s.updateUsages() or %s.updateUsagesInterface()",

                            graph.method().format("%H.%n(%p)"),

                            storeField1.field().getName(),

                            storeField2.field().getName(),

                            Node.class.getName(),

                            Node.class.getName());

        }

    }

    boolean isNodeInput(ResolvedJavaField field, ResolvedJavaType declaringClass, ResolvedJavaType nodeInputList) {

        return declaringClass.isAssignableFrom(field.getDeclaringClass()) && (field.getAnnotation(Input.class) != null || field.getAnnotation(OptionalInput.class) != null) &&

                        !field.getType().equals(nodeInputList);

    }

}