TypeCheckSnippetUtils.java revision 12651:6ef01bd40ce2 
1/*
2 * Copyright (c) 2013, 2014, 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.core.common.GraalOptions.SnippetCounters;
26import static org.graalvm.compiler.hotspot.GraalHotSpotVMConfig.INJECTED_VMCONFIG;
27import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.KLASS_SUPER_CHECK_OFFSET_LOCATION;
28import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.METASPACE_ARRAY_LENGTH_LOCATION;
29import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.PRIMARY_SUPERS_LOCATION;
30import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.SECONDARY_SUPERS_ELEMENT_LOCATION;
31import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.SECONDARY_SUPERS_LOCATION;
32import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.SECONDARY_SUPER_CACHE_LOCATION;
33import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.metaspaceArrayBaseOffset;
34import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.metaspaceArrayLengthOffset;
35import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.secondarySuperCacheOffset;
36import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.secondarySupersOffset;
37import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.superCheckOffsetOffset;
38import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.wordSize;
39import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.NOT_LIKELY_PROBABILITY;
40import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.probability;
41
42import java.util.Arrays;
43
44import org.graalvm.compiler.hotspot.nodes.type.KlassPointerStamp;
45import org.graalvm.compiler.hotspot.word.KlassPointer;
46import org.graalvm.compiler.nodes.ConstantNode;
47import org.graalvm.compiler.nodes.StructuredGraph;
48import org.graalvm.compiler.nodes.TypeCheckHints;
49import org.graalvm.compiler.replacements.SnippetCounter;
50import org.graalvm.compiler.word.Word;
51
52import jdk.vm.ci.hotspot.HotSpotResolvedObjectType;
53import jdk.vm.ci.meta.MetaAccessProvider;
54
55//JaCoCo Exclude
56
57/**
58 * Utilities and common code paths used by the type check snippets.
59 */
60public class TypeCheckSnippetUtils {
61
62    static boolean checkSecondarySubType(KlassPointer t, KlassPointer s) {
63        // if (S.cache == T) return true
64        if (s.readKlassPointer(secondarySuperCacheOffset(INJECTED_VMCONFIG), SECONDARY_SUPER_CACHE_LOCATION).equal(t)) {
65            cacheHit.inc();
66            return true;
67        }
68
69        return checkSelfAndSupers(t, s);
70    }
71
72    static boolean checkUnknownSubType(KlassPointer t, KlassPointer s) {
73        // int off = T.offset
74        int superCheckOffset = t.readInt(superCheckOffsetOffset(INJECTED_VMCONFIG), KLASS_SUPER_CHECK_OFFSET_LOCATION);
75        boolean primary = superCheckOffset != secondarySuperCacheOffset(INJECTED_VMCONFIG);
76
77        // if (T = S[off]) return true
78        if (s.readKlassPointer(superCheckOffset, PRIMARY_SUPERS_LOCATION).equal(t)) {
79            if (primary) {
80                cacheHit.inc();
81            } else {
82                displayHit.inc();
83            }
84            return true;
85        }
86
87        // if (off != &cache) return false
88        if (primary) {
89            displayMiss.inc();
90            return false;
91        }
92
93        return checkSelfAndSupers(t, s);
94    }
95
96    private static boolean checkSelfAndSupers(KlassPointer t, KlassPointer s) {
97        // if (T == S) return true
98        if (s.equal(t)) {
99            T_equals_S.inc();
100            return true;
101        }
102
103        // if (S.scan_s_s_array(T)) { S.cache = T; return true; }
104        Word secondarySupers = s.readWord(secondarySupersOffset(INJECTED_VMCONFIG), SECONDARY_SUPERS_LOCATION);
105        int length = secondarySupers.readInt(metaspaceArrayLengthOffset(INJECTED_VMCONFIG), METASPACE_ARRAY_LENGTH_LOCATION);
106        for (int i = 0; i < length; i++) {
107            if (probability(NOT_LIKELY_PROBABILITY, t.equal(loadSecondarySupersElement(secondarySupers, i)))) {
108                s.writeKlassPointer(secondarySuperCacheOffset(INJECTED_VMCONFIG), t, SECONDARY_SUPER_CACHE_LOCATION);
109                secondariesHit.inc();
110                return true;
111            }
112        }
113        secondariesMiss.inc();
114        return false;
115    }
116
117    /**
118     * A set of type check hints ordered by decreasing probabilities.
119     */
120    public static class Hints {
121
122        /**
123         * The hubs of the hint types.
124         */
125        public final ConstantNode[] hubs;
126
127        /**
128         * A predicate over {@link #hubs} specifying whether the corresponding hint type is a
129         * sub-type of the checked type.
130         */
131        public final boolean[] isPositive;
132
133        Hints(ConstantNode[] hints, boolean[] hintIsPositive) {
134            this.hubs = hints;
135            this.isPositive = hintIsPositive;
136        }
137    }
138
139    static Hints createHints(TypeCheckHints hints, MetaAccessProvider metaAccess, boolean positiveOnly, StructuredGraph graph) {
140        ConstantNode[] hubs = new ConstantNode[hints.hints.length];
141        boolean[] isPositive = new boolean[hints.hints.length];
142        int index = 0;
143        for (int i = 0; i < hubs.length; i++) {
144            if (!positiveOnly || hints.hints[i].positive) {
145                hubs[index] = ConstantNode.forConstant(KlassPointerStamp.klassNonNull(), ((HotSpotResolvedObjectType) hints.hints[i].type).klass(), metaAccess, graph);
146                isPositive[index] = hints.hints[i].positive;
147                index++;
148            }
149        }
150        if (positiveOnly && index != hubs.length) {
151            assert index < hubs.length;
152            hubs = Arrays.copyOf(hubs, index);
153            isPositive = Arrays.copyOf(isPositive, index);
154        }
155        return new Hints(hubs, isPositive);
156    }
157
158    static KlassPointer loadSecondarySupersElement(Word metaspaceArray, int index) {
159        return KlassPointer.fromWord(metaspaceArray.readWord(metaspaceArrayBaseOffset(INJECTED_VMCONFIG) + index * wordSize(), SECONDARY_SUPERS_ELEMENT_LOCATION));
160    }
161
162    private static final SnippetCounter.Group counters = SnippetCounters.getValue() ? new SnippetCounter.Group("TypeCheck") : null;
163    static final SnippetCounter hintsHit = new SnippetCounter(counters, "hintsHit", "hit a hint type");
164    static final SnippetCounter hintsMiss = new SnippetCounter(counters, "hintsMiss", "missed a hint type");
165    static final SnippetCounter exactHit = new SnippetCounter(counters, "exactHit", "exact type test succeeded");
166    static final SnippetCounter exactMiss = new SnippetCounter(counters, "exactMiss", "exact type test failed");
167    static final SnippetCounter isNull = new SnippetCounter(counters, "isNull", "object tested was null");
168    static final SnippetCounter cacheHit = new SnippetCounter(counters, "cacheHit", "secondary type cache hit");
169    static final SnippetCounter secondariesHit = new SnippetCounter(counters, "secondariesHit", "secondaries scan succeeded");
170    static final SnippetCounter secondariesMiss = new SnippetCounter(counters, "secondariesMiss", "secondaries scan failed");
171    static final SnippetCounter displayHit = new SnippetCounter(counters, "displayHit", "primary type test succeeded");
172    static final SnippetCounter displayMiss = new SnippetCounter(counters, "displayMiss", "primary type test failed");
173    static final SnippetCounter T_equals_S = new SnippetCounter(counters, "T_equals_S", "object type was equal to secondary type");
174
175}
176