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Issue 1769043003: Revert of [key-accumulator] Starting to reimplement the key-accumulator (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@master
Patch Set: Created 4 years, 9 months ago
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1 // Copyright 2013 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 #include "src/keys.h"
6
7 #include "src/elements.h"
8 #include "src/factory.h"
9 #include "src/isolate-inl.h"
10 #include "src/objects-inl.h"
11 #include "src/property-descriptor.h"
12 #include "src/prototype.h"
13
14 namespace v8 {
15 namespace internal {
16
17 KeyAccumulator::~KeyAccumulator() {
18 for (size_t i = 0; i < elements_.size(); i++) {
19 delete elements_[i];
20 }
21 }
22
23 Handle<FixedArray> KeyAccumulator::GetKeys(GetKeysConversion convert) {
24 if (length_ == 0) {
25 return isolate_->factory()->empty_fixed_array();
26 }
27 // Make sure we have all the lengths collected.
28 NextPrototype();
29
30 if (type_ == OWN_ONLY && !ownProxyKeys_.is_null()) {
31 return ownProxyKeys_;
32 }
33 // Assemble the result array by first adding the element keys and then the
34 // property keys. We use the total number of String + Symbol keys per level in
35 // |level_lengths_| and the available element keys in the corresponding bucket
36 // in |elements_| to deduce the number of keys to take from the
37 // |string_properties_| and |symbol_properties_| set.
38 Handle<FixedArray> result = isolate_->factory()->NewFixedArray(length_);
39 int insertion_index = 0;
40 int string_properties_index = 0;
41 int symbol_properties_index = 0;
42 // String and Symbol lengths always come in pairs:
43 size_t max_level = level_lengths_.size() / 2;
44 for (size_t level = 0; level < max_level; level++) {
45 int num_string_properties = level_lengths_[level * 2];
46 int num_symbol_properties = level_lengths_[level * 2 + 1];
47 if (num_string_properties < 0) {
48 // If the |num_string_properties| is negative, the current level contains
49 // properties from a proxy, hence we skip the integer keys in |elements_|
50 // since proxies define the complete ordering.
51 num_string_properties = -num_string_properties;
52 } else if (level < elements_.size()) {
53 // Add the element indices for this prototype level.
54 std::vector<uint32_t>* elements = elements_[level];
55 int num_elements = static_cast<int>(elements->size());
56 for (int i = 0; i < num_elements; i++) {
57 Handle<Object> key;
58 if (convert == KEEP_NUMBERS) {
59 key = isolate_->factory()->NewNumberFromUint(elements->at(i));
60 } else {
61 key = isolate_->factory()->Uint32ToString(elements->at(i));
62 }
63 result->set(insertion_index, *key);
64 insertion_index++;
65 }
66 }
67 // Add the string property keys for this prototype level.
68 for (int i = 0; i < num_string_properties; i++) {
69 Object* key = string_properties_->KeyAt(string_properties_index);
70 result->set(insertion_index, key);
71 insertion_index++;
72 string_properties_index++;
73 }
74 // Add the symbol property keys for this prototype level.
75 for (int i = 0; i < num_symbol_properties; i++) {
76 Object* key = symbol_properties_->KeyAt(symbol_properties_index);
77 result->set(insertion_index, key);
78 insertion_index++;
79 symbol_properties_index++;
80 }
81 }
82
83 DCHECK_EQ(insertion_index, length_);
84 return result;
85 }
86
87 namespace {
88
89 bool AccumulatorHasKey(std::vector<uint32_t>* sub_elements, uint32_t key) {
90 return std::binary_search(sub_elements->begin(), sub_elements->end(), key);
91 }
92
93 } // namespace
94
95 bool KeyAccumulator::AddKey(Object* key, AddKeyConversion convert) {
96 return AddKey(handle(key, isolate_), convert);
97 }
98
99 bool KeyAccumulator::AddKey(Handle<Object> key, AddKeyConversion convert) {
100 if (key->IsSymbol()) {
101 if (filter_ & SKIP_SYMBOLS) return false;
102 if (Handle<Symbol>::cast(key)->is_private()) return false;
103 return AddSymbolKey(key);
104 }
105 if (filter_ & SKIP_STRINGS) return false;
106 // Make sure we do not add keys to a proxy-level (see AddKeysFromProxy).
107 DCHECK_LE(0, level_string_length_);
108 // In some cases (e.g. proxies) we might get in String-converted ints which
109 // should be added to the elements list instead of the properties. For
110 // proxies we have to convert as well but also respect the original order.
111 // Therefore we add a converted key to both sides
112 if (convert == CONVERT_TO_ARRAY_INDEX || convert == PROXY_MAGIC) {
113 uint32_t index = 0;
114 int prev_length = length_;
115 int prev_proto = level_string_length_;
116 if ((key->IsString() && Handle<String>::cast(key)->AsArrayIndex(&index)) ||
117 key->ToArrayIndex(&index)) {
118 bool key_was_added = AddIntegerKey(index);
119 if (convert == CONVERT_TO_ARRAY_INDEX) return key_was_added;
120 if (convert == PROXY_MAGIC) {
121 // If we had an array index (number) and it wasn't added, the key
122 // already existed before, hence we cannot add it to the properties
123 // keys as it would lead to duplicate entries.
124 if (!key_was_added) {
125 return false;
126 }
127 length_ = prev_length;
128 level_string_length_ = prev_proto;
129 }
130 }
131 }
132 return AddStringKey(key, convert);
133 }
134
135 bool KeyAccumulator::AddKey(uint32_t key) { return AddIntegerKey(key); }
136
137 bool KeyAccumulator::AddIntegerKey(uint32_t key) {
138 // Make sure we do not add keys to a proxy-level (see AddKeysFromProxy).
139 // We mark proxy-levels with a negative length
140 DCHECK_LE(0, level_string_length_);
141 // Binary search over all but the last level. The last one might not be
142 // sorted yet.
143 for (size_t i = 1; i < elements_.size(); i++) {
144 if (AccumulatorHasKey(elements_[i - 1], key)) return false;
145 }
146 elements_.back()->push_back(key);
147 length_++;
148 return true;
149 }
150
151 bool KeyAccumulator::AddStringKey(Handle<Object> key,
152 AddKeyConversion convert) {
153 if (string_properties_.is_null()) {
154 string_properties_ = OrderedHashSet::Allocate(isolate_, 16);
155 }
156 // TODO(cbruni): remove this conversion once we throw the correct TypeError
157 // for non-string/symbol elements returned by proxies
158 if (convert == PROXY_MAGIC && key->IsNumber()) {
159 key = isolate_->factory()->NumberToString(key);
160 }
161 int prev_size = string_properties_->NumberOfElements();
162 string_properties_ = OrderedHashSet::Add(string_properties_, key);
163 if (prev_size < string_properties_->NumberOfElements()) {
164 length_++;
165 level_string_length_++;
166 return true;
167 } else {
168 return false;
169 }
170 }
171
172 bool KeyAccumulator::AddSymbolKey(Handle<Object> key) {
173 if (symbol_properties_.is_null()) {
174 symbol_properties_ = OrderedHashSet::Allocate(isolate_, 16);
175 }
176 int prev_size = symbol_properties_->NumberOfElements();
177 symbol_properties_ = OrderedHashSet::Add(symbol_properties_, key);
178 if (prev_size < symbol_properties_->NumberOfElements()) {
179 length_++;
180 level_symbol_length_++;
181 return true;
182 } else {
183 return false;
184 }
185 }
186
187 void KeyAccumulator::AddKeys(Handle<FixedArray> array,
188 AddKeyConversion convert) {
189 int add_length = array->length();
190 if (add_length == 0) return;
191 for (int i = 0; i < add_length; i++) {
192 Handle<Object> current(array->get(i), isolate_);
193 AddKey(current, convert);
194 }
195 }
196
197 void KeyAccumulator::AddKeys(Handle<JSObject> array_like,
198 AddKeyConversion convert) {
199 DCHECK(array_like->IsJSArray() || array_like->HasSloppyArgumentsElements());
200 ElementsAccessor* accessor = array_like->GetElementsAccessor();
201 accessor->AddElementsToKeyAccumulator(array_like, this, convert);
202 }
203
204 void KeyAccumulator::AddKeysFromProxy(Handle<JSObject> array_like) {
205 // Proxies define a complete list of keys with no distinction of
206 // elements and properties, which breaks the normal assumption for the
207 // KeyAccumulator.
208 AddKeys(array_like, PROXY_MAGIC);
209 // Invert the current length to indicate a present proxy, so we can ignore
210 // element keys for this level. Otherwise we would not fully respect the order
211 // given by the proxy.
212 level_string_length_ = -level_string_length_;
213 }
214
215 MaybeHandle<FixedArray> FilterProxyKeys(Isolate* isolate, Handle<JSProxy> owner,
216 Handle<FixedArray> keys,
217 PropertyFilter filter) {
218 if (filter == ALL_PROPERTIES) {
219 // Nothing to do.
220 return keys;
221 }
222 int store_position = 0;
223 for (int i = 0; i < keys->length(); ++i) {
224 Handle<Name> key(Name::cast(keys->get(i)), isolate);
225 if (key->FilterKey(filter)) continue; // Skip this key.
226 if (filter & ONLY_ENUMERABLE) {
227 PropertyDescriptor desc;
228 Maybe<bool> found =
229 JSProxy::GetOwnPropertyDescriptor(isolate, owner, key, &desc);
230 MAYBE_RETURN(found, MaybeHandle<FixedArray>());
231 if (!found.FromJust() || !desc.enumerable()) continue; // Skip this key.
232 }
233 // Keep this key.
234 if (store_position != i) {
235 keys->set(store_position, *key);
236 }
237 store_position++;
238 }
239 if (store_position == 0) return isolate->factory()->empty_fixed_array();
240 keys->Shrink(store_position);
241 return keys;
242 }
243
244 // Returns "nothing" in case of exception, "true" on success.
245 Maybe<bool> KeyAccumulator::AddKeysFromProxy(Handle<JSProxy> proxy,
246 Handle<FixedArray> keys) {
247 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
248 isolate_, keys, FilterProxyKeys(isolate_, proxy, keys, filter_),
249 Nothing<bool>());
250 // Proxies define a complete list of keys with no distinction of
251 // elements and properties, which breaks the normal assumption for the
252 // KeyAccumulator.
253 if (type_ == OWN_ONLY) {
254 ownProxyKeys_ = keys;
255 level_string_length_ = keys->length();
256 length_ = level_string_length_;
257 } else {
258 AddKeys(keys, PROXY_MAGIC);
259 }
260 // Invert the current length to indicate a present proxy, so we can ignore
261 // element keys for this level. Otherwise we would not fully respect the order
262 // given by the proxy.
263 level_string_length_ = -level_string_length_;
264 return Just(true);
265 }
266
267 void KeyAccumulator::AddElementKeysFromInterceptor(
268 Handle<JSObject> array_like) {
269 AddKeys(array_like, CONVERT_TO_ARRAY_INDEX);
270 // The interceptor might introduce duplicates for the current level, since
271 // these keys get added after the objects's normal element keys.
272 SortCurrentElementsListRemoveDuplicates();
273 }
274
275 void KeyAccumulator::SortCurrentElementsListRemoveDuplicates() {
276 // Sort and remove duplicates from the current elements level and adjust.
277 // the lengths accordingly.
278 auto last_level = elements_.back();
279 size_t nof_removed_keys = last_level->size();
280 std::sort(last_level->begin(), last_level->end());
281 last_level->erase(std::unique(last_level->begin(), last_level->end()),
282 last_level->end());
283 // Adjust total length by the number of removed duplicates.
284 nof_removed_keys -= last_level->size();
285 length_ -= static_cast<int>(nof_removed_keys);
286 }
287
288 void KeyAccumulator::SortCurrentElementsList() {
289 if (elements_.empty()) return;
290 auto element_keys = elements_.back();
291 std::sort(element_keys->begin(), element_keys->end());
292 }
293
294 void KeyAccumulator::NextPrototype() {
295 // Store the protoLength on the first call of this method.
296 if (!elements_.empty()) {
297 level_lengths_.push_back(level_string_length_);
298 level_lengths_.push_back(level_symbol_length_);
299 }
300 elements_.push_back(new std::vector<uint32_t>());
301 level_string_length_ = 0;
302 level_symbol_length_ = 0;
303 }
304
305 namespace {
306
307 void TrySettingEmptyEnumCache(JSReceiver* object) {
308 Map* map = object->map();
309 DCHECK_EQ(kInvalidEnumCacheSentinel, map->EnumLength());
310 if (!map->OnlyHasSimpleProperties()) return;
311 if (map->IsJSProxyMap()) return;
312 if (map->NumberOfOwnDescriptors() > 0) {
313 int number_of_enumerable_own_properties =
314 map->NumberOfDescribedProperties(OWN_DESCRIPTORS, ENUMERABLE_STRINGS);
315 if (number_of_enumerable_own_properties > 0) return;
316 }
317 DCHECK(object->IsJSObject());
318 map->SetEnumLength(0);
319 }
320
321 bool CheckAndInitalizeSimpleEnumCache(JSReceiver* object) {
322 if (object->map()->EnumLength() == kInvalidEnumCacheSentinel) {
323 TrySettingEmptyEnumCache(object);
324 }
325 if (object->map()->EnumLength() != 0) return false;
326 DCHECK(object->IsJSObject());
327 return !JSObject::cast(object)->HasEnumerableElements();
328 }
329 } // namespace
330
331 void FastKeyAccumulator::Prepare() {
332 DisallowHeapAllocation no_gc;
333 // Directly go for the fast path for OWN_ONLY keys.
334 if (type_ == OWN_ONLY) return;
335 // Fully walk the prototype chain and find the last prototype with keys.
336 is_receiver_simple_enum_ = false;
337 has_empty_prototype_ = true;
338 JSReceiver* first_non_empty_prototype;
339 for (PrototypeIterator iter(isolate_, *receiver_); !iter.IsAtEnd();
340 iter.Advance()) {
341 JSReceiver* current = iter.GetCurrent<JSReceiver>();
342 if (CheckAndInitalizeSimpleEnumCache(current)) continue;
343 has_empty_prototype_ = false;
344 first_non_empty_prototype = current;
345 // TODO(cbruni): use the first non-empty prototype.
346 USE(first_non_empty_prototype);
347 return;
348 }
349 DCHECK(has_empty_prototype_);
350 is_receiver_simple_enum_ =
351 receiver_->map()->EnumLength() != kInvalidEnumCacheSentinel &&
352 !JSObject::cast(*receiver_)->HasEnumerableElements();
353 }
354
355 namespace {
356 Handle<FixedArray> GetOwnKeysWithElements(Isolate* isolate,
357 Handle<JSObject> object,
358 GetKeysConversion convert) {
359 Handle<FixedArray> keys = JSObject::GetFastEnumPropertyKeys(isolate, object);
360 ElementsAccessor* accessor = object->GetElementsAccessor();
361 return accessor->PrependElementIndices(object, keys, convert,
362 ONLY_ENUMERABLE);
363 }
364
365 MaybeHandle<FixedArray> GetOwnKeysWithUninitializedEnumCache(
366 Isolate* isolate, Handle<JSObject> object) {
367 // Uninitalized enum cache
368 Map* map = object->map();
369 if (object->elements() != isolate->heap()->empty_fixed_array() ||
370 object->elements() != isolate->heap()->empty_slow_element_dictionary()) {
371 // Assume that there are elements.
372 return MaybeHandle<FixedArray>();
373 }
374 int number_of_own_descriptors = map->NumberOfOwnDescriptors();
375 if (number_of_own_descriptors == 0) {
376 map->SetEnumLength(0);
377 return isolate->factory()->empty_fixed_array();
378 }
379 // We have no elements but possibly enumerable property keys, hence we can
380 // directly initialize the enum cache.
381 return JSObject::GetFastEnumPropertyKeys(isolate, object);
382 }
383
384 } // namespace
385
386 MaybeHandle<FixedArray> FastKeyAccumulator::GetKeys(GetKeysConversion convert) {
387 Handle<FixedArray> keys;
388 if (GetKeysFast(convert).ToHandle(&keys)) {
389 return keys;
390 }
391 return GetKeysSlow(convert);
392 }
393
394 MaybeHandle<FixedArray> FastKeyAccumulator::GetKeysFast(
395 GetKeysConversion convert) {
396 bool own_only = has_empty_prototype_ || type_ == OWN_ONLY;
397 if (!own_only || !receiver_->map()->OnlyHasSimpleProperties()) {
398 return MaybeHandle<FixedArray>();
399 }
400
401 Handle<FixedArray> keys;
402 DCHECK(receiver_->IsJSObject());
403 Handle<JSObject> object = Handle<JSObject>::cast(receiver_);
404
405 int enum_length = receiver_->map()->EnumLength();
406 if (enum_length == kInvalidEnumCacheSentinel) {
407 // Try initializing the enum cache and return own properties.
408 if (GetOwnKeysWithUninitializedEnumCache(isolate_, object)
409 .ToHandle(&keys)) {
410 is_receiver_simple_enum_ =
411 object->map()->EnumLength() != kInvalidEnumCacheSentinel;
412 return keys;
413 }
414 }
415 // The properties-only case failed because there were probably elements on the
416 // receiver.
417 return GetOwnKeysWithElements(isolate_, object, convert);
418 }
419
420 MaybeHandle<FixedArray> FastKeyAccumulator::GetKeysSlow(
421 GetKeysConversion convert) {
422 return JSReceiver::GetKeys(receiver_, type_, ENUMERABLE_STRINGS);
423 }
424
425 } // namespace internal
426 } // namespace v8
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