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
|
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* Copyright 2016 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "wasm/WasmCompartment.h"
#include "jscompartment.h"
#include "wasm/WasmInstance.h"
#include "vm/Debugger-inl.h"
using namespace js;
using namespace wasm;
Compartment::Compartment(Zone* zone)
: mutatingInstances_(false),
activationCount_(0),
profilingEnabled_(false)
{}
Compartment::~Compartment()
{
MOZ_ASSERT(activationCount_ == 0);
MOZ_ASSERT(instances_.empty());
MOZ_ASSERT(!mutatingInstances_);
}
struct InstanceComparator
{
const Instance& target;
explicit InstanceComparator(const Instance& target) : target(target) {}
int operator()(const Instance* instance) const {
if (instance == &target)
return 0;
MOZ_ASSERT(!target.codeSegment().containsCodePC(instance->codeBase()));
MOZ_ASSERT(!instance->codeSegment().containsCodePC(target.codeBase()));
return target.codeBase() < instance->codeBase() ? -1 : 1;
}
};
void
Compartment::trace(JSTracer* trc)
{
// A WasmInstanceObject that was initially reachable when called can become
// unreachable while executing on the stack. Since wasm does not otherwise
// scan the stack during GC to identify live instances, we mark all instance
// objects live if there is any running wasm in the compartment.
if (activationCount_) {
for (Instance* i : instances_)
i->trace(trc);
}
}
bool
Compartment::registerInstance(JSContext* cx, HandleWasmInstanceObject instanceObj)
{
Instance& instance = instanceObj->instance();
MOZ_ASSERT(this == &instance.compartment()->wasm);
if (!instance.ensureProfilingState(cx, profilingEnabled_))
return false;
size_t index;
if (BinarySearchIf(instances_, 0, instances_.length(), InstanceComparator(instance), &index))
MOZ_CRASH("duplicate registration");
{
AutoMutateInstances guard(*this);
if (!instances_.insert(instances_.begin() + index, &instance)) {
ReportOutOfMemory(cx);
return false;
}
}
Debugger::onNewWasmInstance(cx, instanceObj);
return true;
}
void
Compartment::unregisterInstance(Instance& instance)
{
size_t index;
if (!BinarySearchIf(instances_, 0, instances_.length(), InstanceComparator(instance), &index))
return;
AutoMutateInstances guard(*this);
instances_.erase(instances_.begin() + index);
}
struct PCComparator
{
const void* pc;
explicit PCComparator(const void* pc) : pc(pc) {}
int operator()(const Instance* instance) const {
if (instance->codeSegment().containsCodePC(pc))
return 0;
return pc < instance->codeBase() ? -1 : 1;
}
};
Code*
Compartment::lookupCode(const void* pc) const
{
Instance* instance = lookupInstanceDeprecated(pc);
return instance ? &instance->code() : nullptr;
}
Instance*
Compartment::lookupInstanceDeprecated(const void* pc) const
{
// lookupInstanceDeprecated can be called asynchronously from the interrupt
// signal handler. In that case, the signal handler is just asking whether
// the pc is in wasm code. If instances_ is being mutated then we can't be
// executing wasm code so returning nullptr is fine.
if (mutatingInstances_)
return nullptr;
size_t index;
if (!BinarySearchIf(instances_, 0, instances_.length(), PCComparator(pc), &index))
return nullptr;
return instances_[index];
}
bool
Compartment::ensureProfilingState(JSContext* cx)
{
bool newProfilingEnabled = cx->spsProfiler.enabled();
if (profilingEnabled_ == newProfilingEnabled)
return true;
// Since one Instance can call another Instance in the same compartment
// directly without calling through Instance::callExport(), when profiling
// is enabled, enable it for the entire compartment at once. It is only safe
// to enable profiling when the wasm is not on the stack, so delay enabling
// profiling until there are no live WasmActivations in this compartment.
if (activationCount_ > 0)
return true;
for (Instance* instance : instances_) {
if (!instance->ensureProfilingState(cx, newProfilingEnabled))
return false;
}
profilingEnabled_ = newProfilingEnabled;
return true;
}
bool
Compartment::profilingEnabled() const
{
// Profiling can asynchronously interrupt the mutation of the instances_
// vector which is used by lookupCode() during stack-walking. To handle
// this rare case, disable profiling during mutation.
return profilingEnabled_ && !mutatingInstances_;
}
void
Compartment::addSizeOfExcludingThis(MallocSizeOf mallocSizeOf, size_t* compartmentTables)
{
*compartmentTables += instances_.sizeOfExcludingThis(mallocSizeOf);
}
|
