summaryrefslogtreecommitdiffstats
path: root/js/src/gc/Barrier.cpp
blob: 6dab8d25b45028d373c381044aab4b687672260e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "gc/Barrier.h"

#include "jscompartment.h"
#include "jsobj.h"

#include "builtin/TypedObject.h"
#include "gc/Policy.h"
#include "gc/Zone.h"
#include "js/HashTable.h"
#include "js/Value.h"
#include "vm/EnvironmentObject.h"
#include "vm/SharedArrayObject.h"
#include "vm/Symbol.h"
#include "wasm/WasmJS.h"

namespace js {

bool
RuntimeFromMainThreadIsHeapMajorCollecting(JS::shadow::Zone* shadowZone)
{
    return shadowZone->runtimeFromMainThread()->isHeapMajorCollecting();
}

#ifdef DEBUG

bool
IsMarkedBlack(NativeObject* obj)
{
    // Note: we assume conservatively that Nursery things will be live.
    if (!obj->isTenured())
        return true;

    gc::TenuredCell& tenured = obj->asTenured();
    return (tenured.isMarked(gc::BLACK) && !tenured.isMarked(gc::GRAY)) ||
           tenured.arena()->allocatedDuringIncremental;
}

bool
HeapSlot::preconditionForSet(NativeObject* owner, Kind kind, uint32_t slot) const
{
    return kind == Slot
         ? &owner->getSlotRef(slot) == this
         : &owner->getDenseElement(slot) == (const Value*)this;
}

bool
HeapSlot::preconditionForWriteBarrierPost(NativeObject* obj, Kind kind, uint32_t slot,
                                          const Value& target) const
{
    bool isCorrectSlot = kind == Slot
                         ? obj->getSlotAddressUnchecked(slot)->get() == target
                         : static_cast<HeapSlot*>(obj->getDenseElements() + slot)->get() == target;
    bool isBlackToGray = target.isGCThing() &&
                         IsMarkedBlack(obj) && JS::GCThingIsMarkedGray(JS::GCCellPtr(target));
    return isCorrectSlot && !isBlackToGray;
}

bool
CurrentThreadIsIonCompiling()
{
    return TlsPerThreadData.get()->ionCompiling;
}

bool
CurrentThreadIsIonCompilingSafeForMinorGC()
{
    return TlsPerThreadData.get()->ionCompilingSafeForMinorGC;
}

bool
CurrentThreadIsGCSweeping()
{
    return TlsPerThreadData.get()->gcSweeping;
}

#endif // DEBUG

template <typename S>
template <typename T>
void
ReadBarrierFunctor<S>::operator()(T* t)
{
    InternalBarrierMethods<T*>::readBarrier(t);
}

// All GC things may be held in a Value, either publicly or as a private GC
// thing.
#define JS_EXPAND_DEF(name, type, _) \
template void ReadBarrierFunctor<JS::Value>::operator()<type>(type*);
JS_FOR_EACH_TRACEKIND(JS_EXPAND_DEF);
#undef JS_EXPAND_DEF

template <typename S>
template <typename T>
void
PreBarrierFunctor<S>::operator()(T* t)
{
    InternalBarrierMethods<T*>::preBarrier(t);
}

// All GC things may be held in a Value, either publicly or as a private GC
// thing.
#define JS_EXPAND_DEF(name, type, _) \
template void PreBarrierFunctor<JS::Value>::operator()<type>(type*);
JS_FOR_EACH_TRACEKIND(JS_EXPAND_DEF);
#undef JS_EXPAND_DEF

template void PreBarrierFunctor<jsid>::operator()<JS::Symbol>(JS::Symbol*);
template void PreBarrierFunctor<jsid>::operator()<JSString>(JSString*);

template <typename T>
/* static */ bool
MovableCellHasher<T>::hasHash(const Lookup& l)
{
    if (!l)
        return true;

    return l->zoneFromAnyThread()->hasUniqueId(l);
}

template <typename T>
/* static */ bool
MovableCellHasher<T>::ensureHash(const Lookup& l)
{
    if (!l)
        return true;

    uint64_t unusedId;
    return l->zoneFromAnyThread()->getUniqueId(l, &unusedId);
}

template <typename T>
/* static */ HashNumber
MovableCellHasher<T>::hash(const Lookup& l)
{
    if (!l)
        return 0;

    // We have to access the zone from-any-thread here: a worker thread may be
    // cloning a self-hosted object from the main-thread-runtime-owned self-
    // hosting zone into the off-main-thread runtime. The zone's uid lock will
    // protect against multiple workers doing this simultaneously.
    MOZ_ASSERT(CurrentThreadCanAccessZone(l->zoneFromAnyThread()) ||
               l->zoneFromAnyThread()->isSelfHostingZone());

    return l->zoneFromAnyThread()->getHashCodeInfallible(l);
}

template <typename T>
/* static */ bool
MovableCellHasher<T>::match(const Key& k, const Lookup& l)
{
    // Return true if both are null or false if only one is null.
    if (!k)
        return !l;
    if (!l)
        return false;

    MOZ_ASSERT(k);
    MOZ_ASSERT(l);
    MOZ_ASSERT(CurrentThreadCanAccessZone(l->zoneFromAnyThread()) ||
               l->zoneFromAnyThread()->isSelfHostingZone());

    Zone* zone = k->zoneFromAnyThread();
    if (zone != l->zoneFromAnyThread())
        return false;
    MOZ_ASSERT(zone->hasUniqueId(k));
    MOZ_ASSERT(zone->hasUniqueId(l));

    // Since both already have a uid (from hash), the get is infallible.
    return zone->getUniqueIdInfallible(k) == zone->getUniqueIdInfallible(l);
}

#ifdef JS_BROKEN_GCC_ATTRIBUTE_WARNING
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wattributes"
#endif // JS_BROKEN_GCC_ATTRIBUTE_WARNING

template struct JS_PUBLIC_API(MovableCellHasher<JSObject*>);
template struct JS_PUBLIC_API(MovableCellHasher<GlobalObject*>);
template struct JS_PUBLIC_API(MovableCellHasher<SavedFrame*>);
template struct JS_PUBLIC_API(MovableCellHasher<EnvironmentObject*>);
template struct JS_PUBLIC_API(MovableCellHasher<WasmInstanceObject*>);
template struct JS_PUBLIC_API(MovableCellHasher<JSScript*>);

#ifdef JS_BROKEN_GCC_ATTRIBUTE_WARNING
#pragma GCC diagnostic pop
#endif // JS_BROKEN_GCC_ATTRIBUTE_WARNING

} // namespace js

JS_PUBLIC_API(void)
JS::HeapObjectPostBarrier(JSObject** objp, JSObject* prev, JSObject* next)
{
    MOZ_ASSERT(objp);
    js::InternalBarrierMethods<JSObject*>::postBarrier(objp, prev, next);
}

JS_PUBLIC_API(void)
JS::HeapValuePostBarrier(JS::Value* valuep, const Value& prev, const Value& next)
{
    MOZ_ASSERT(valuep);
    js::InternalBarrierMethods<JS::Value>::postBarrier(valuep, prev, next);
}