1 // Copyright 2018 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #ifndef V8_OBJECTS_ALLOCATION_SITE_INL_H_
6 #define V8_OBJECTS_ALLOCATION_SITE_INL_H_
7
8 #include "src/objects/allocation-site.h"
9
10 #include "src/heap/heap-write-barrier-inl.h"
11 #include "src/objects/js-objects-inl.h"
12
13 // Has to be the last include (doesn't have include guards):
14 #include "src/objects/object-macros.h"
15
16 namespace v8 {
17 namespace internal {
18
19 #include "torque-generated/src/objects/allocation-site-tq-inl.inc"
20
21 TQ_OBJECT_CONSTRUCTORS_IMPL(AllocationMemento)
OBJECT_CONSTRUCTORS_IMPL(AllocationSite,Struct)22 OBJECT_CONSTRUCTORS_IMPL(AllocationSite, Struct)
23
24 NEVER_READ_ONLY_SPACE_IMPL(AllocationSite)
25
26 CAST_ACCESSOR(AllocationSite)
27
28 ACCESSORS(AllocationSite, transition_info_or_boilerplate, Object,
29 kTransitionInfoOrBoilerplateOffset)
30 ACCESSORS(AllocationSite, nested_site, Object, kNestedSiteOffset)
31 INT32_ACCESSORS(AllocationSite, pretenure_data, kPretenureDataOffset)
32 INT32_ACCESSORS(AllocationSite, pretenure_create_count,
33 kPretenureCreateCountOffset)
34 ACCESSORS(AllocationSite, dependent_code, DependentCode, kDependentCodeOffset)
35 ACCESSORS_CHECKED(AllocationSite, weak_next, Object, kWeakNextOffset,
36 HasWeakNext())
37 ACCESSORS(AllocationMemento, allocation_site, Object, kAllocationSiteOffset)
38
39 JSObject AllocationSite::boilerplate() const {
40 DCHECK(PointsToLiteral());
41 return JSObject::cast(transition_info_or_boilerplate());
42 }
43
set_boilerplate(JSObject object,WriteBarrierMode mode)44 void AllocationSite::set_boilerplate(JSObject object, WriteBarrierMode mode) {
45 set_transition_info_or_boilerplate(object, mode);
46 }
47
transition_info()48 int AllocationSite::transition_info() const {
49 DCHECK(!PointsToLiteral());
50 return Smi::cast(transition_info_or_boilerplate()).value();
51 }
52
set_transition_info(int value)53 void AllocationSite::set_transition_info(int value) {
54 DCHECK(!PointsToLiteral());
55 set_transition_info_or_boilerplate(Smi::FromInt(value), SKIP_WRITE_BARRIER);
56 }
57
HasWeakNext()58 bool AllocationSite::HasWeakNext() const {
59 return map() == GetReadOnlyRoots().allocation_site_map();
60 }
61
Initialize()62 void AllocationSite::Initialize() {
63 set_transition_info_or_boilerplate(Smi::zero());
64 SetElementsKind(GetInitialFastElementsKind());
65 set_nested_site(Smi::zero());
66 set_pretenure_data(0);
67 set_pretenure_create_count(0);
68 set_dependent_code(
69 DependentCode::cast(GetReadOnlyRoots().empty_weak_fixed_array()),
70 SKIP_WRITE_BARRIER);
71 }
72
IsZombie()73 bool AllocationSite::IsZombie() const {
74 return pretenure_decision() == kZombie;
75 }
76
IsMaybeTenure()77 bool AllocationSite::IsMaybeTenure() const {
78 return pretenure_decision() == kMaybeTenure;
79 }
80
PretenuringDecisionMade()81 bool AllocationSite::PretenuringDecisionMade() const {
82 return pretenure_decision() != kUndecided;
83 }
84
MarkZombie()85 void AllocationSite::MarkZombie() {
86 DCHECK(!IsZombie());
87 Initialize();
88 set_pretenure_decision(kZombie);
89 }
90
GetElementsKind()91 ElementsKind AllocationSite::GetElementsKind() const {
92 return ElementsKindBits::decode(transition_info());
93 }
94
SetElementsKind(ElementsKind kind)95 void AllocationSite::SetElementsKind(ElementsKind kind) {
96 set_transition_info(ElementsKindBits::update(transition_info(), kind));
97 }
98
CanInlineCall()99 bool AllocationSite::CanInlineCall() const {
100 return DoNotInlineBit::decode(transition_info()) == 0;
101 }
102
SetDoNotInlineCall()103 void AllocationSite::SetDoNotInlineCall() {
104 set_transition_info(DoNotInlineBit::update(transition_info(), true));
105 }
106
PointsToLiteral()107 bool AllocationSite::PointsToLiteral() const {
108 Object raw_value = transition_info_or_boilerplate();
109 DCHECK_EQ(!raw_value.IsSmi(),
110 raw_value.IsJSArray() || raw_value.IsJSObject());
111 return !raw_value.IsSmi();
112 }
113
114 // Heuristic: We only need to create allocation site info if the boilerplate
115 // elements kind is the initial elements kind.
ShouldTrack(ElementsKind boilerplate_elements_kind)116 bool AllocationSite::ShouldTrack(ElementsKind boilerplate_elements_kind) {
117 return IsSmiElementsKind(boilerplate_elements_kind);
118 }
119
CanTrack(InstanceType type)120 inline bool AllocationSite::CanTrack(InstanceType type) {
121 if (FLAG_allocation_site_pretenuring) {
122 // TurboFan doesn't care at all about String pretenuring feedback,
123 // so don't bother even trying to track that.
124 return type == JS_ARRAY_TYPE || type == JS_OBJECT_TYPE;
125 }
126 return type == JS_ARRAY_TYPE;
127 }
128
pretenure_decision()129 AllocationSite::PretenureDecision AllocationSite::pretenure_decision() const {
130 return PretenureDecisionBits::decode(pretenure_data());
131 }
132
set_pretenure_decision(PretenureDecision decision)133 void AllocationSite::set_pretenure_decision(PretenureDecision decision) {
134 int32_t value = pretenure_data();
135 set_pretenure_data(PretenureDecisionBits::update(value, decision));
136 }
137
deopt_dependent_code()138 bool AllocationSite::deopt_dependent_code() const {
139 return DeoptDependentCodeBit::decode(pretenure_data());
140 }
141
set_deopt_dependent_code(bool deopt)142 void AllocationSite::set_deopt_dependent_code(bool deopt) {
143 int32_t value = pretenure_data();
144 set_pretenure_data(DeoptDependentCodeBit::update(value, deopt));
145 }
146
memento_found_count()147 int AllocationSite::memento_found_count() const {
148 return MementoFoundCountBits::decode(pretenure_data());
149 }
150
set_memento_found_count(int count)151 inline void AllocationSite::set_memento_found_count(int count) {
152 int32_t value = pretenure_data();
153 // Verify that we can count more mementos than we can possibly find in one
154 // new space collection.
155 DCHECK((GetHeap()->MaxSemiSpaceSize() /
156 (Heap::kMinObjectSizeInTaggedWords * kTaggedSize +
157 AllocationMemento::kSize)) < MementoFoundCountBits::kMax);
158 DCHECK_LT(count, MementoFoundCountBits::kMax);
159 set_pretenure_data(MementoFoundCountBits::update(value, count));
160 }
161
memento_create_count()162 int AllocationSite::memento_create_count() const {
163 return pretenure_create_count();
164 }
165
set_memento_create_count(int count)166 void AllocationSite::set_memento_create_count(int count) {
167 set_pretenure_create_count(count);
168 }
169
IncrementMementoFoundCount(int increment)170 bool AllocationSite::IncrementMementoFoundCount(int increment) {
171 if (IsZombie()) return false;
172
173 int value = memento_found_count();
174 set_memento_found_count(value + increment);
175 return memento_found_count() >= kPretenureMinimumCreated;
176 }
177
IncrementMementoCreateCount()178 inline void AllocationSite::IncrementMementoCreateCount() {
179 DCHECK(FLAG_allocation_site_pretenuring);
180 int value = memento_create_count();
181 set_memento_create_count(value + 1);
182 }
183
IsValid()184 bool AllocationMemento::IsValid() const {
185 return allocation_site().IsAllocationSite() &&
186 !AllocationSite::cast(allocation_site()).IsZombie();
187 }
188
GetAllocationSite()189 AllocationSite AllocationMemento::GetAllocationSite() const {
190 DCHECK(IsValid());
191 return AllocationSite::cast(allocation_site());
192 }
193
GetAllocationSiteUnchecked()194 Address AllocationMemento::GetAllocationSiteUnchecked() const {
195 return allocation_site().ptr();
196 }
197
198 template <AllocationSiteUpdateMode update_or_check>
DigestTransitionFeedback(Handle<AllocationSite> site,ElementsKind to_kind)199 bool AllocationSite::DigestTransitionFeedback(Handle<AllocationSite> site,
200 ElementsKind to_kind) {
201 Isolate* isolate = site->GetIsolate();
202 bool result = false;
203
204 if (site->PointsToLiteral() && site->boilerplate().IsJSArray()) {
205 Handle<JSArray> boilerplate(JSArray::cast(site->boilerplate()), isolate);
206 ElementsKind kind = boilerplate->GetElementsKind();
207 // if kind is holey ensure that to_kind is as well.
208 if (IsHoleyElementsKind(kind)) {
209 to_kind = GetHoleyElementsKind(to_kind);
210 }
211 if (IsMoreGeneralElementsKindTransition(kind, to_kind)) {
212 // If the array is huge, it's not likely to be defined in a local
213 // function, so we shouldn't make new instances of it very often.
214 uint32_t length = 0;
215 CHECK(boilerplate->length().ToArrayLength(&length));
216 if (length <= kMaximumArrayBytesToPretransition) {
217 if (update_or_check == AllocationSiteUpdateMode::kCheckOnly) {
218 return true;
219 }
220 if (FLAG_trace_track_allocation_sites) {
221 bool is_nested = site->IsNested();
222 PrintF("AllocationSite: JSArray %p boilerplate %supdated %s->%s\n",
223 reinterpret_cast<void*>(site->ptr()),
224 is_nested ? "(nested)" : " ", ElementsKindToString(kind),
225 ElementsKindToString(to_kind));
226 }
227 JSObject::TransitionElementsKind(boilerplate, to_kind);
228 site->dependent_code().DeoptimizeDependentCodeGroup(
229 DependentCode::kAllocationSiteTransitionChangedGroup);
230 result = true;
231 }
232 }
233 } else {
234 // The AllocationSite is for a constructed Array.
235 ElementsKind kind = site->GetElementsKind();
236 // if kind is holey ensure that to_kind is as well.
237 if (IsHoleyElementsKind(kind)) {
238 to_kind = GetHoleyElementsKind(to_kind);
239 }
240 if (IsMoreGeneralElementsKindTransition(kind, to_kind)) {
241 if (update_or_check == AllocationSiteUpdateMode::kCheckOnly) return true;
242 if (FLAG_trace_track_allocation_sites) {
243 PrintF("AllocationSite: JSArray %p site updated %s->%s\n",
244 reinterpret_cast<void*>(site->ptr()), ElementsKindToString(kind),
245 ElementsKindToString(to_kind));
246 }
247 site->SetElementsKind(to_kind);
248 site->dependent_code().DeoptimizeDependentCodeGroup(
249 DependentCode::kAllocationSiteTransitionChangedGroup);
250 result = true;
251 }
252 }
253 return result;
254 }
255
256 } // namespace internal
257 } // namespace v8
258
259 #include "src/objects/object-macros-undef.h"
260
261 #endif // V8_OBJECTS_ALLOCATION_SITE_INL_H_
262