HashCodeSnippets.java revision 12651:6ef01bd40ce2 
1/*
2 * Copyright (c) 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.hotspot.replacements;
24
25import static org.graalvm.compiler.hotspot.GraalHotSpotVMConfig.INJECTED_VMCONFIG;
26import static org.graalvm.compiler.hotspot.meta.HotSpotForeignCallsProviderImpl.IDENTITY_HASHCODE;
27import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.biasedLockMaskInPlace;
28import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.identityHashCode;
29import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.identityHashCodeShift;
30import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.loadWordFromObject;
31import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.markOffset;
32import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.uninitializedIdentityHashCodeValue;
33import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.unlockedMask;
34import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.FAST_PATH_PROBABILITY;
35import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.NOT_FREQUENT_PROBABILITY;
36import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.probability;
37
38import org.graalvm.compiler.api.replacements.Snippet;
39import org.graalvm.compiler.hotspot.meta.HotSpotProviders;
40import org.graalvm.compiler.nodes.StructuredGraph;
41import org.graalvm.compiler.nodes.spi.LoweringTool;
42import org.graalvm.compiler.replacements.SnippetTemplate;
43import org.graalvm.compiler.replacements.SnippetTemplate.AbstractTemplates;
44import org.graalvm.compiler.replacements.SnippetTemplate.Arguments;
45import org.graalvm.compiler.replacements.SnippetTemplate.SnippetInfo;
46import org.graalvm.compiler.replacements.Snippets;
47import org.graalvm.compiler.word.Word;
48
49import jdk.vm.ci.code.TargetDescription;
50
51public class HashCodeSnippets implements Snippets {
52
53    @Snippet
54    public static int identityHashCodeSnippet(final Object thisObj) {
55        if (probability(NOT_FREQUENT_PROBABILITY, thisObj == null)) {
56            return 0;
57        }
58        return computeHashCode(thisObj);
59    }
60
61    static int computeHashCode(final Object x) {
62        Word mark = loadWordFromObject(x, markOffset(INJECTED_VMCONFIG));
63
64        // this code is independent from biased locking (although it does not look that way)
65        final Word biasedLock = mark.and(biasedLockMaskInPlace(INJECTED_VMCONFIG));
66        if (probability(FAST_PATH_PROBABILITY, biasedLock.equal(Word.unsigned(unlockedMask(INJECTED_VMCONFIG))))) {
67            int hash = (int) mark.unsignedShiftRight(identityHashCodeShift(INJECTED_VMCONFIG)).rawValue();
68            if (probability(FAST_PATH_PROBABILITY, hash != uninitializedIdentityHashCodeValue(INJECTED_VMCONFIG))) {
69                return hash;
70            }
71        }
72        return identityHashCode(IDENTITY_HASHCODE, x);
73    }
74
75    public static class Templates extends AbstractTemplates {
76
77        private final SnippetInfo identityHashCodeSnippet = snippet(HashCodeSnippets.class, "identityHashCodeSnippet", HotSpotReplacementsUtil.MARK_WORD_LOCATION);
78
79        public Templates(HotSpotProviders providers, TargetDescription target) {
80            super(providers, providers.getSnippetReflection(), target);
81        }
82
83        public void lower(IdentityHashCodeNode node, LoweringTool tool) {
84            StructuredGraph graph = node.graph();
85            Arguments args = new Arguments(identityHashCodeSnippet, graph.getGuardsStage(), tool.getLoweringStage());
86            args.add("thisObj", node.object);
87            SnippetTemplate template = template(args);
88            template.instantiate(providers.getMetaAccess(), node, SnippetTemplate.DEFAULT_REPLACER, args);
89        }
90
91    }
92
93}
94