1/*
2 * Copyright (c) 2013, 2016, 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.replacements;
24
25import static org.graalvm.compiler.core.common.GraalOptions.SnippetCounters;
26import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_IGNORED;
27import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_IGNORED;
28import static org.graalvm.compiler.replacements.SnippetTemplate.DEFAULT_REPLACER;
29
30import java.lang.reflect.Field;
31import java.util.Arrays;
32
33import org.graalvm.compiler.api.replacements.Fold;
34import org.graalvm.compiler.api.replacements.Snippet;
35import org.graalvm.compiler.api.replacements.Snippet.ConstantParameter;
36import org.graalvm.compiler.api.replacements.SnippetReflectionProvider;
37import org.graalvm.compiler.core.common.LocationIdentity;
38import org.graalvm.compiler.core.common.type.StampFactory;
39import org.graalvm.compiler.debug.GraalError;
40import org.graalvm.compiler.graph.NodeClass;
41import org.graalvm.compiler.nodeinfo.NodeInfo;
42import org.graalvm.compiler.nodes.FixedWithNextNode;
43import org.graalvm.compiler.nodes.NamedLocationIdentity;
44import org.graalvm.compiler.nodes.StructuredGraph;
45import org.graalvm.compiler.nodes.ValueNode;
46import org.graalvm.compiler.nodes.spi.Lowerable;
47import org.graalvm.compiler.nodes.spi.LoweringTool;
48import org.graalvm.compiler.phases.util.Providers;
49import org.graalvm.compiler.replacements.SnippetTemplate.AbstractTemplates;
50import org.graalvm.compiler.replacements.SnippetTemplate.Arguments;
51import org.graalvm.compiler.replacements.SnippetTemplate.SnippetInfo;
52import org.graalvm.compiler.word.ObjectAccess;
53
54import jdk.vm.ci.code.TargetDescription;
55import sun.misc.Unsafe;
56
57/**
58 * This node can be used to add a counter to the code that will estimate the dynamic number of calls
59 * by adding an increment to the compiled code. This should of course only be used for
60 * debugging/testing purposes.
61 *
62 * A unique counter will be created for each unique name passed to the constructor. Depending on the
63 * value of withContext, the name of the root method is added to the counter's name.
64 */
65@NodeInfo(cycles = CYCLES_IGNORED, size = SIZE_IGNORED)
66public class SnippetCounterNode extends FixedWithNextNode implements Lowerable {
67
68    public static final NodeClass<SnippetCounterNode> TYPE = NodeClass.create(SnippetCounterNode.class);
69
70    @Input protected ValueNode increment;
71
72    protected final SnippetCounter counter;
73
74    public SnippetCounterNode(SnippetCounter counter, ValueNode increment) {
75        super(TYPE, StampFactory.forVoid());
76        this.counter = counter;
77        this.increment = increment;
78    }
79
80    public SnippetCounter getCounter() {
81        return counter;
82    }
83
84    public ValueNode getIncrement() {
85        return increment;
86    }
87
88    @NodeIntrinsic
89    public static native void add(@ConstantNodeParameter SnippetCounter counter, int increment);
90
91    public static void increment(@ConstantNodeParameter SnippetCounter counter) {
92        add(counter, 1);
93    }
94
95    @Override
96    public void lower(LoweringTool tool) {
97        if (graph().getGuardsStage().areFrameStatesAtDeopts()) {
98            SnippetCounterSnippets.Templates templates = tool.getReplacements().getSnippetTemplateCache(SnippetCounterSnippets.Templates.class);
99            templates.lower(this, tool);
100        }
101    }
102
103    /**
104     * When {@link #SnippetCounters} are enabled make sure {@link #SNIPPET_COUNTER_LOCATION} is part
105     * of the private locations.
106     *
107     * @param privateLocations
108     * @return a copy of privateLocations with any needed locations added
109     */
110    public static LocationIdentity[] addSnippetCounters(LocationIdentity[] privateLocations) {
111        if (SnippetCounters.getValue()) {
112            for (LocationIdentity location : privateLocations) {
113                if (location.equals(SNIPPET_COUNTER_LOCATION)) {
114                    return privateLocations;
115                }
116            }
117            LocationIdentity[] result = Arrays.copyOf(privateLocations, privateLocations.length + 1);
118            result[result.length - 1] = SnippetCounterNode.SNIPPET_COUNTER_LOCATION;
119            return result;
120        }
121        return privateLocations;
122    }
123
124    /**
125     * We do not want to use the {@link LocationIdentity} of the {@link SnippetCounter#value} field,
126     * so that the usage in snippets is always possible. If a method accesses the counter via the
127     * field and the snippet, the result might not be correct though.
128     */
129    public static final LocationIdentity SNIPPET_COUNTER_LOCATION = NamedLocationIdentity.mutable("SnippetCounter");
130
131    static class SnippetCounterSnippets implements Snippets {
132
133        @Fold
134        static int countOffset() {
135            try {
136                return (int) UNSAFE.objectFieldOffset(SnippetCounter.class.getDeclaredField("value"));
137            } catch (Exception e) {
138                throw new GraalError(e);
139            }
140        }
141
142        @Snippet
143        public static void add(@ConstantParameter SnippetCounter counter, int increment) {
144            long loadedValue = ObjectAccess.readLong(counter, countOffset(), SNIPPET_COUNTER_LOCATION);
145            ObjectAccess.writeLong(counter, countOffset(), loadedValue + increment, SNIPPET_COUNTER_LOCATION);
146        }
147
148        public static class Templates extends AbstractTemplates {
149
150            private final SnippetInfo add = snippet(SnippetCounterSnippets.class, "add", SNIPPET_COUNTER_LOCATION);
151
152            Templates(Providers providers, SnippetReflectionProvider snippetReflection, TargetDescription target) {
153                super(providers, snippetReflection, target);
154            }
155
156            public void lower(SnippetCounterNode counter, LoweringTool tool) {
157                StructuredGraph graph = counter.graph();
158                Arguments args = new Arguments(add, graph.getGuardsStage(), tool.getLoweringStage());
159                args.addConst("counter", counter.getCounter());
160                args.add("increment", counter.getIncrement());
161
162                template(args).instantiate(providers.getMetaAccess(), counter, DEFAULT_REPLACER, args);
163            }
164        }
165    }
166
167    private static final Unsafe UNSAFE = initUnsafe();
168
169    private static Unsafe initUnsafe() {
170        try {
171            return Unsafe.getUnsafe();
172        } catch (SecurityException se) {
173            try {
174                Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");
175                theUnsafe.setAccessible(true);
176                return (Unsafe) theUnsafe.get(Unsafe.class);
177            } catch (Exception e) {
178                throw new RuntimeException("exception while trying to get Unsafe", e);
179            }
180        }
181    }
182}
183