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
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
|
// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_OBJECTS_ALLOCATION_SITE_INL_H_
#define V8_OBJECTS_ALLOCATION_SITE_INL_H_
#include "src/objects/allocation-site.h"
#include "src/heap/heap-write-barrier-inl.h"
#include "src/objects/js-objects-inl.h"
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
namespace v8 {
namespace internal {
OBJECT_CONSTRUCTORS_IMPL(AllocationMemento, Struct)
OBJECT_CONSTRUCTORS_IMPL(AllocationSite, Struct)
NEVER_READ_ONLY_SPACE_IMPL(AllocationSite)
CAST_ACCESSOR(AllocationMemento)
CAST_ACCESSOR(AllocationSite)
ACCESSORS(AllocationSite, transition_info_or_boilerplate, Object,
kTransitionInfoOrBoilerplateOffset)
ACCESSORS(AllocationSite, nested_site, Object, kNestedSiteOffset)
INT32_ACCESSORS(AllocationSite, pretenure_data, kPretenureDataOffset)
INT32_ACCESSORS(AllocationSite, pretenure_create_count,
kPretenureCreateCountOffset)
ACCESSORS(AllocationSite, dependent_code, DependentCode, kDependentCodeOffset)
ACCESSORS_CHECKED(AllocationSite, weak_next, Object, kWeakNextOffset,
HasWeakNext())
ACCESSORS(AllocationMemento, allocation_site, Object, kAllocationSiteOffset)
JSObject AllocationSite::boilerplate() const {
DCHECK(PointsToLiteral());
return JSObject::cast(transition_info_or_boilerplate());
}
void AllocationSite::set_boilerplate(JSObject object, WriteBarrierMode mode) {
set_transition_info_or_boilerplate(object, mode);
}
int AllocationSite::transition_info() const {
DCHECK(!PointsToLiteral());
return Smi::cast(transition_info_or_boilerplate()).value();
}
void AllocationSite::set_transition_info(int value) {
DCHECK(!PointsToLiteral());
set_transition_info_or_boilerplate(Smi::FromInt(value), SKIP_WRITE_BARRIER);
}
bool AllocationSite::HasWeakNext() const {
return map() == GetReadOnlyRoots().allocation_site_map();
}
void AllocationSite::Initialize() {
set_transition_info_or_boilerplate(Smi::zero());
SetElementsKind(GetInitialFastElementsKind());
set_nested_site(Smi::zero());
set_pretenure_data(0);
set_pretenure_create_count(0);
set_dependent_code(
DependentCode::cast(GetReadOnlyRoots().empty_weak_fixed_array()),
SKIP_WRITE_BARRIER);
}
bool AllocationSite::IsZombie() const {
return pretenure_decision() == kZombie;
}
bool AllocationSite::IsMaybeTenure() const {
return pretenure_decision() == kMaybeTenure;
}
bool AllocationSite::PretenuringDecisionMade() const {
return pretenure_decision() != kUndecided;
}
void AllocationSite::MarkZombie() {
DCHECK(!IsZombie());
Initialize();
set_pretenure_decision(kZombie);
}
ElementsKind AllocationSite::GetElementsKind() const {
return ElementsKindBits::decode(transition_info());
}
void AllocationSite::SetElementsKind(ElementsKind kind) {
set_transition_info(ElementsKindBits::update(transition_info(), kind));
}
bool AllocationSite::CanInlineCall() const {
return DoNotInlineBit::decode(transition_info()) == 0;
}
void AllocationSite::SetDoNotInlineCall() {
set_transition_info(DoNotInlineBit::update(transition_info(), true));
}
bool AllocationSite::PointsToLiteral() const {
Object raw_value = transition_info_or_boilerplate();
DCHECK_EQ(!raw_value.IsSmi(),
raw_value.IsJSArray() || raw_value.IsJSObject());
return !raw_value.IsSmi();
}
// Heuristic: We only need to create allocation site info if the boilerplate
// elements kind is the initial elements kind.
bool AllocationSite::ShouldTrack(ElementsKind boilerplate_elements_kind) {
return IsSmiElementsKind(boilerplate_elements_kind);
}
inline bool AllocationSite::CanTrack(InstanceType type) {
if (FLAG_allocation_site_pretenuring) {
// TurboFan doesn't care at all about String pretenuring feedback,
// so don't bother even trying to track that.
return type == JS_ARRAY_TYPE || type == JS_OBJECT_TYPE;
}
return type == JS_ARRAY_TYPE;
}
AllocationSite::PretenureDecision AllocationSite::pretenure_decision() const {
return PretenureDecisionBits::decode(pretenure_data());
}
void AllocationSite::set_pretenure_decision(PretenureDecision decision) {
int32_t value = pretenure_data();
set_pretenure_data(PretenureDecisionBits::update(value, decision));
}
bool AllocationSite::deopt_dependent_code() const {
return DeoptDependentCodeBit::decode(pretenure_data());
}
void AllocationSite::set_deopt_dependent_code(bool deopt) {
int32_t value = pretenure_data();
set_pretenure_data(DeoptDependentCodeBit::update(value, deopt));
}
int AllocationSite::memento_found_count() const {
return MementoFoundCountBits::decode(pretenure_data());
}
inline void AllocationSite::set_memento_found_count(int count) {
int32_t value = pretenure_data();
// Verify that we can count more mementos than we can possibly find in one
// new space collection.
DCHECK((GetHeap()->MaxSemiSpaceSize() /
(Heap::kMinObjectSizeInTaggedWords * kTaggedSize +
AllocationMemento::kSize)) < MementoFoundCountBits::kMax);
DCHECK_LT(count, MementoFoundCountBits::kMax);
set_pretenure_data(MementoFoundCountBits::update(value, count));
}
int AllocationSite::memento_create_count() const {
return pretenure_create_count();
}
void AllocationSite::set_memento_create_count(int count) {
set_pretenure_create_count(count);
}
bool AllocationSite::IncrementMementoFoundCount(int increment) {
if (IsZombie()) return false;
int value = memento_found_count();
set_memento_found_count(value + increment);
return memento_found_count() >= kPretenureMinimumCreated;
}
inline void AllocationSite::IncrementMementoCreateCount() {
DCHECK(FLAG_allocation_site_pretenuring);
int value = memento_create_count();
set_memento_create_count(value + 1);
}
bool AllocationMemento::IsValid() const {
return allocation_site().IsAllocationSite() &&
!AllocationSite::cast(allocation_site()).IsZombie();
}
AllocationSite AllocationMemento::GetAllocationSite() const {
DCHECK(IsValid());
return AllocationSite::cast(allocation_site());
}
Address AllocationMemento::GetAllocationSiteUnchecked() const {
return allocation_site().ptr();
}
template <AllocationSiteUpdateMode update_or_check>
bool AllocationSite::DigestTransitionFeedback(Handle<AllocationSite> site,
ElementsKind to_kind) {
Isolate* isolate = site->GetIsolate();
bool result = false;
if (site->PointsToLiteral() && site->boilerplate().IsJSArray()) {
Handle<JSArray> boilerplate(JSArray::cast(site->boilerplate()), isolate);
ElementsKind kind = boilerplate->GetElementsKind();
// if kind is holey ensure that to_kind is as well.
if (IsHoleyElementsKind(kind)) {
to_kind = GetHoleyElementsKind(to_kind);
}
if (IsMoreGeneralElementsKindTransition(kind, to_kind)) {
// If the array is huge, it's not likely to be defined in a local
// function, so we shouldn't make new instances of it very often.
uint32_t length = 0;
CHECK(boilerplate->length().ToArrayLength(&length));
if (length <= kMaximumArrayBytesToPretransition) {
if (update_or_check == AllocationSiteUpdateMode::kCheckOnly) {
return true;
}
if (FLAG_trace_track_allocation_sites) {
bool is_nested = site->IsNested();
PrintF("AllocationSite: JSArray %p boilerplate %supdated %s->%s\n",
reinterpret_cast<void*>(site->ptr()),
is_nested ? "(nested)" : " ", ElementsKindToString(kind),
ElementsKindToString(to_kind));
}
JSObject::TransitionElementsKind(boilerplate, to_kind);
site->dependent_code().DeoptimizeDependentCodeGroup(
DependentCode::kAllocationSiteTransitionChangedGroup);
result = true;
}
}
} else {
// The AllocationSite is for a constructed Array.
ElementsKind kind = site->GetElementsKind();
// if kind is holey ensure that to_kind is as well.
if (IsHoleyElementsKind(kind)) {
to_kind = GetHoleyElementsKind(to_kind);
}
if (IsMoreGeneralElementsKindTransition(kind, to_kind)) {
if (update_or_check == AllocationSiteUpdateMode::kCheckOnly) return true;
if (FLAG_trace_track_allocation_sites) {
PrintF("AllocationSite: JSArray %p site updated %s->%s\n",
reinterpret_cast<void*>(site->ptr()), ElementsKindToString(kind),
ElementsKindToString(to_kind));
}
site->SetElementsKind(to_kind);
site->dependent_code().DeoptimizeDependentCodeGroup(
DependentCode::kAllocationSiteTransitionChangedGroup);
result = true;
}
}
return result;
}
} // namespace internal
} // namespace v8
#include "src/objects/object-macros-undef.h"
#endif // V8_OBJECTS_ALLOCATION_SITE_INL_H_
|