1/*
2 * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23package org.graalvm.compiler.phases.verify;
24
25import java.util.List;
26
27import org.graalvm.compiler.graph.Node;
28import org.graalvm.compiler.graph.Node.Input;
29import org.graalvm.compiler.graph.Node.OptionalInput;
30import org.graalvm.compiler.graph.NodeInputList;
31import org.graalvm.compiler.nodes.StructuredGraph;
32import org.graalvm.compiler.nodes.java.LoadFieldNode;
33import org.graalvm.compiler.nodes.java.MethodCallTargetNode;
34import org.graalvm.compiler.nodes.java.StoreFieldNode;
35import org.graalvm.compiler.phases.VerifyPhase;
36import org.graalvm.compiler.phases.tiers.PhaseContext;
37
38import jdk.vm.ci.meta.ResolvedJavaField;
39import jdk.vm.ci.meta.ResolvedJavaMethod;
40import jdk.vm.ci.meta.ResolvedJavaType;
41
42/**
43 * Try to ensure that methods which update {@link Input} or {@link OptionalInput} fields also
44 * include a call to {@link Node#updateUsages} or {@link Node#updateUsagesInterface}.
45 */
46public class VerifyUpdateUsages extends VerifyPhase<PhaseContext> {
47
48    @Override
49    public boolean checkContract() {
50        return false;
51    }
52
53    public VerifyUpdateUsages() {
54    }
55
56    @Override
57    protected boolean verify(StructuredGraph graph, PhaseContext context) {
58        if (graph.method().isConstructor()) {
59            return true;
60        }
61        /*
62         * There are only two acceptable patterns for methods which update Node inputs, either a
63         * single StoreField node and invoke of updateUsages or updateUsagesInterface, or 2
64         * StoreFields that come from LoadFields on the same object. Other patterns can be added as
65         * needed but it would be best to keep things simple so that verification can be simple.
66         */
67        List<StoreFieldNode> stores = graph.getNodes().filter(StoreFieldNode.class).snapshot();
68        ResolvedJavaType declaringClass = graph.method().getDeclaringClass();
69        ResolvedJavaType nodeInputList = context.getMetaAccess().lookupJavaType(NodeInputList.class);
70        StoreFieldNode storeField1 = null;
71        StoreFieldNode storeField2 = null;
72        for (StoreFieldNode store : stores) {
73            if (isNodeInput(store.field(), declaringClass, nodeInputList)) {
74                if (storeField1 == null) {
75                    storeField1 = store;
76                } else if (storeField2 == null) {
77                    storeField2 = store;
78                } else {
79                    return false;
80                }
81            }
82        }
83        if (storeField1 == null) {
84            return true;
85        }
86        if (storeField2 == null) {
87            // Single input field update so just check for updateUsages or updateUsagesInterface
88            // call
89            ResolvedJavaType node = context.getMetaAccess().lookupJavaType(Node.class);
90            for (MethodCallTargetNode call : graph.getNodes().filter(MethodCallTargetNode.class)) {
91                ResolvedJavaMethod callee = call.targetMethod();
92                if (callee.getDeclaringClass().equals(node) && (callee.getName().equals("updateUsages") || callee.getName().equals("updateUsagesInterface"))) {
93                    return true;
94                }
95            }
96        } else {
97            if (storeField1.value() instanceof LoadFieldNode && storeField2.value() instanceof LoadFieldNode) {
98                LoadFieldNode load1 = (LoadFieldNode) storeField1.value();
99                LoadFieldNode load2 = (LoadFieldNode) storeField2.value();
100                // Check for swapping values within the same object
101                if (load1.object() == storeField1.object() && load2.object() == storeField2.object() && storeField1.object() == storeField2.object() &&
102                                load1.field().equals(storeField2.field()) && load2.field().equals(storeField1.field())) {
103                    return true;
104                }
105            }
106        }
107        return false;
108    }
109
110    boolean isNodeInput(ResolvedJavaField field, ResolvedJavaType declaringClass, ResolvedJavaType nodeInputList) {
111        return declaringClass.isAssignableFrom(field.getDeclaringClass()) && (field.getAnnotation(Input.class) != null || field.getAnnotation(OptionalInput.class) != null) &&
112                        !field.getType().equals(nodeInputList);
113    }
114}
115