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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_JS_OBJECTS_H_
6 #define V8_OBJECTS_JS_OBJECTS_H_
7 
8 #include "src/objects/embedder-data-slot.h"
9 // TODO(jkummerow): Consider forward-declaring instead.
10 #include "src/objects/internal-index.h"
11 #include "src/objects/objects.h"
12 #include "src/objects/property-array.h"
13 
14 // Has to be the last include (doesn't have include guards):
15 #include "src/objects/object-macros.h"
16 
17 namespace v8 {
18 namespace internal {
19 
20 // Enum for functions that offer a second mode that does not cause allocations.
21 // Used in conjunction with LookupIterator and unboxed double fields.
22 enum class AllocationPolicy { kAllocationAllowed, kAllocationDisallowed };
23 
24 enum InstanceType : uint16_t;
25 class JSGlobalObject;
26 class JSGlobalProxy;
27 class LookupIterator;
28 class PropertyKey;
29 class NativeContext;
30 class IsCompiledScope;
31 
32 #include "torque-generated/src/objects/js-objects-tq.inc"
33 
34 // JSReceiver includes types on which properties can be defined, i.e.,
35 // JSObject and JSProxy.
36 class JSReceiver : public TorqueGeneratedJSReceiver<JSReceiver, HeapObject> {
37  public:
38   NEVER_READ_ONLY_SPACE
39   // Returns true if there is no slow (ie, dictionary) backing store.
40   DECL_GETTER(HasFastProperties, bool)
41 
42   // Returns the properties array backing store if it
43   // exists. Otherwise, returns an empty_property_array when there's a
44   // Smi (hash code) or an empty_fixed_array for a fast properties
45   // map.
46   DECL_GETTER(property_array, PropertyArray)
47 
48   // Gets slow properties for non-global objects (if
49   // v8_enable_swiss_name_dictionary is not set).
50   DECL_GETTER(property_dictionary, NameDictionary)
51 
52   // Gets slow properties for non-global objects (if
53   // v8_enable_swiss_name_dictionary is set).
54   DECL_GETTER(property_dictionary_swiss, SwissNameDictionary)
55 
56   // Sets the properties backing store and makes sure any existing hash is moved
57   // to the new properties store. To clear out the properties store, pass in the
58   // empty_fixed_array(), the hash will be maintained in this case as well.
59   void SetProperties(HeapObject properties);
60 
61   // There are five possible values for the properties offset.
62   // 1) EmptyFixedArray/EmptyPropertyDictionary - This is the standard
63   // placeholder.
64   //
65   // 2) Smi - This is the hash code of the object.
66   //
67   // 3) PropertyArray - This is similar to a FixedArray but stores
68   // the hash code of the object in its length field. This is a fast
69   // backing store.
70   //
71   // 4) NameDictionary - This is the dictionary-mode backing store.
72   //
73   // 4) GlobalDictionary - This is the backing store for the
74   // GlobalObject.
75   //
76   // This is used only in the deoptimizer and heap. Please use the
77   // above typed getters and setters to access the properties.
78   DECL_ACCESSORS(raw_properties_or_hash, Object)
79   DECL_RELAXED_ACCESSORS(raw_properties_or_hash, Object)
80 
81   inline void initialize_properties(Isolate* isolate);
82 
83   // Deletes an existing named property in a normalized object.
84   static void DeleteNormalizedProperty(Handle<JSReceiver> object,
85                                        InternalIndex entry);
86 
87   // ES6 section 7.1.1 ToPrimitive
88   V8_WARN_UNUSED_RESULT static MaybeHandle<Object> ToPrimitive(
89       Isolate* isolate, Handle<JSReceiver> receiver,
90       ToPrimitiveHint hint = ToPrimitiveHint::kDefault);
91 
92   // ES6 section 7.1.1.1 OrdinaryToPrimitive
93   V8_WARN_UNUSED_RESULT static MaybeHandle<Object> OrdinaryToPrimitive(
94       Isolate* isolate, Handle<JSReceiver> receiver,
95       OrdinaryToPrimitiveHint hint);
96 
97   static MaybeHandle<NativeContext> GetFunctionRealm(
98       Handle<JSReceiver> receiver);
99   V8_EXPORT_PRIVATE static MaybeHandle<NativeContext> GetContextForMicrotask(
100       Handle<JSReceiver> receiver);
101 
102   // Get the first non-hidden prototype.
103   static inline MaybeHandle<HeapObject> GetPrototype(
104       Isolate* isolate, Handle<JSReceiver> receiver);
105 
106   V8_WARN_UNUSED_RESULT static Maybe<bool> HasInPrototypeChain(
107       Isolate* isolate, Handle<JSReceiver> object, Handle<Object> proto);
108 
109   // Reads all enumerable own properties of source and adds them to
110   // target, using either Set or CreateDataProperty depending on the
111   // use_set argument. This only copies values not present in the
112   // maybe_excluded_properties list.
113   V8_WARN_UNUSED_RESULT static Maybe<bool> SetOrCopyDataProperties(
114       Isolate* isolate, Handle<JSReceiver> target, Handle<Object> source,
115       PropertiesEnumerationMode mode,
116       const base::ScopedVector<Handle<Object>>* excluded_properties = nullptr,
117       bool use_set = true);
118 
119   // Implementation of [[HasProperty]], ECMA-262 5th edition, section 8.12.6.
120   V8_EXPORT_PRIVATE V8_WARN_UNUSED_RESULT static Maybe<bool> HasProperty(
121       LookupIterator* it);
122   V8_WARN_UNUSED_RESULT static inline Maybe<bool> HasProperty(
123       Isolate* isolate, Handle<JSReceiver> object, Handle<Name> name);
124   V8_WARN_UNUSED_RESULT static inline Maybe<bool> HasElement(
125       Isolate* isolate, Handle<JSReceiver> object, uint32_t index);
126 
127   V8_EXPORT_PRIVATE V8_WARN_UNUSED_RESULT static Maybe<bool> HasOwnProperty(
128       Isolate* isolate, Handle<JSReceiver> object, Handle<Name> name);
129   V8_WARN_UNUSED_RESULT static inline Maybe<bool> HasOwnProperty(
130       Isolate* isolate, Handle<JSReceiver> object, uint32_t index);
131 
132   V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> GetProperty(
133       Isolate* isolate, Handle<JSReceiver> receiver, const char* key);
134   V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> GetProperty(
135       Isolate* isolate, Handle<JSReceiver> receiver, Handle<Name> name);
136   V8_WARN_UNUSED_RESULT static inline MaybeHandle<Object> GetElement(
137       Isolate* isolate, Handle<JSReceiver> receiver, uint32_t index);
138 
139   // Implementation of ES6 [[Delete]]
140   V8_EXPORT_PRIVATE V8_WARN_UNUSED_RESULT static Maybe<bool>
141   DeletePropertyOrElement(Handle<JSReceiver> object, Handle<Name> name,
142                           LanguageMode language_mode = LanguageMode::kSloppy);
143   V8_EXPORT_PRIVATE V8_WARN_UNUSED_RESULT static Maybe<bool> DeleteProperty(
144       Handle<JSReceiver> object, Handle<Name> name,
145       LanguageMode language_mode = LanguageMode::kSloppy);
146   V8_WARN_UNUSED_RESULT static Maybe<bool> DeleteProperty(
147       LookupIterator* it, LanguageMode language_mode);
148   V8_WARN_UNUSED_RESULT static Maybe<bool> DeleteElement(
149       Handle<JSReceiver> object, uint32_t index,
150       LanguageMode language_mode = LanguageMode::kSloppy);
151 
152   V8_WARN_UNUSED_RESULT static Object DefineProperty(Isolate* isolate,
153                                                      Handle<Object> object,
154                                                      Handle<Object> name,
155                                                      Handle<Object> attributes);
156   V8_WARN_UNUSED_RESULT static MaybeHandle<Object> DefineProperties(
157       Isolate* isolate, Handle<Object> object, Handle<Object> properties);
158 
159   // "virtual" dispatcher to the correct [[DefineOwnProperty]] implementation.
160   V8_WARN_UNUSED_RESULT static Maybe<bool> DefineOwnProperty(
161       Isolate* isolate, Handle<JSReceiver> object, Handle<Object> key,
162       PropertyDescriptor* desc, Maybe<ShouldThrow> should_throw);
163 
164   // Check if private name property can be store on the object. It will return
165   // false with an error when it cannot.
166   V8_WARN_UNUSED_RESULT static bool CheckPrivateNameStore(LookupIterator* it,
167                                                           bool is_define);
168 
169   // Check if a data property can be created on the object. It will fail with
170   // an error when it cannot.
171   V8_WARN_UNUSED_RESULT static Maybe<bool> CheckIfCanDefine(
172       Isolate* isolate, LookupIterator* it, Handle<Object> value,
173       Maybe<ShouldThrow> should_throw);
174 
175   // ES6 7.3.4 (when passed kDontThrow)
176   V8_WARN_UNUSED_RESULT static Maybe<bool> CreateDataProperty(
177       Isolate* isolate, Handle<JSReceiver> object, Handle<Name> key,
178       Handle<Object> value, Maybe<ShouldThrow> should_throw);
179   V8_WARN_UNUSED_RESULT static Maybe<bool> CreateDataProperty(
180       LookupIterator* it, Handle<Object> value,
181       Maybe<ShouldThrow> should_throw);
182 
183   // Add private fields to the receiver, ignoring extensibility and the
184   // traps. The caller should check that the private field does not already
185   // exist on the receiver before calling this method.
186   V8_WARN_UNUSED_RESULT static Maybe<bool> AddPrivateField(
187       LookupIterator* it, Handle<Object> value,
188       Maybe<ShouldThrow> should_throw);
189 
190   // ES6 9.1.6.1
191   V8_WARN_UNUSED_RESULT static Maybe<bool> OrdinaryDefineOwnProperty(
192       Isolate* isolate, Handle<JSObject> object, Handle<Object> key,
193       PropertyDescriptor* desc, Maybe<ShouldThrow> should_throw);
194   V8_WARN_UNUSED_RESULT static Maybe<bool> OrdinaryDefineOwnProperty(
195       Isolate* isolate, Handle<JSObject> object, const PropertyKey& key,
196       PropertyDescriptor* desc, Maybe<ShouldThrow> should_throw);
197   V8_WARN_UNUSED_RESULT static Maybe<bool> OrdinaryDefineOwnProperty(
198       LookupIterator* it, PropertyDescriptor* desc,
199       Maybe<ShouldThrow> should_throw);
200   // ES6 9.1.6.2
201   V8_WARN_UNUSED_RESULT static Maybe<bool> IsCompatiblePropertyDescriptor(
202       Isolate* isolate, bool extensible, PropertyDescriptor* desc,
203       PropertyDescriptor* current, Handle<Name> property_name,
204       Maybe<ShouldThrow> should_throw);
205   // ES6 9.1.6.3
206   // |it| can be NULL in cases where the ES spec passes |undefined| as the
207   // receiver. Exactly one of |it| and |property_name| must be provided.
208   V8_WARN_UNUSED_RESULT static Maybe<bool> ValidateAndApplyPropertyDescriptor(
209       Isolate* isolate, LookupIterator* it, bool extensible,
210       PropertyDescriptor* desc, PropertyDescriptor* current,
211       Maybe<ShouldThrow> should_throw, Handle<Name> property_name);
212 
213   V8_EXPORT_PRIVATE V8_WARN_UNUSED_RESULT static Maybe<bool>
214   GetOwnPropertyDescriptor(Isolate* isolate, Handle<JSReceiver> object,
215                            Handle<Object> key, PropertyDescriptor* desc);
216   V8_WARN_UNUSED_RESULT static Maybe<bool> GetOwnPropertyDescriptor(
217       LookupIterator* it, PropertyDescriptor* desc);
218 
219   using IntegrityLevel = PropertyAttributes;
220 
221   // ES6 7.3.14 (when passed kDontThrow)
222   // 'level' must be SEALED or FROZEN.
223   V8_WARN_UNUSED_RESULT static Maybe<bool> SetIntegrityLevel(
224       Handle<JSReceiver> object, IntegrityLevel lvl, ShouldThrow should_throw);
225 
226   // ES6 7.3.15
227   // 'level' must be SEALED or FROZEN.
228   V8_WARN_UNUSED_RESULT static Maybe<bool> TestIntegrityLevel(
229       Handle<JSReceiver> object, IntegrityLevel lvl);
230 
231   // ES6 [[PreventExtensions]] (when passed kDontThrow)
232   V8_WARN_UNUSED_RESULT static Maybe<bool> PreventExtensions(
233       Handle<JSReceiver> object, ShouldThrow should_throw);
234 
235   V8_WARN_UNUSED_RESULT static Maybe<bool> IsExtensible(
236       Handle<JSReceiver> object);
237 
238   // Returns the class name.
239   V8_EXPORT_PRIVATE String class_name();
240 
241   // Returns the constructor (the function that was used to instantiate the
242   // object).
243   static MaybeHandle<JSFunction> GetConstructor(Isolate* isolate,
244                                                 Handle<JSReceiver> receiver);
245 
246   // Returns the constructor name (the (possibly inferred) name of the function
247   // that was used to instantiate the object), if any. If a FunctionTemplate is
248   // used to instantiate the object, the class_name of the FunctionTemplate is
249   // returned instead.
250   static Handle<String> GetConstructorName(Isolate* isolate,
251                                            Handle<JSReceiver> receiver);
252 
253   V8_EXPORT_PRIVATE MaybeHandle<NativeContext> GetCreationContext();
254 
255   V8_WARN_UNUSED_RESULT static inline Maybe<PropertyAttributes>
256   GetPropertyAttributes(Handle<JSReceiver> object, Handle<Name> name);
257   V8_WARN_UNUSED_RESULT static inline Maybe<PropertyAttributes>
258   GetOwnPropertyAttributes(Handle<JSReceiver> object, Handle<Name> name);
259   V8_WARN_UNUSED_RESULT static inline Maybe<PropertyAttributes>
260   GetOwnPropertyAttributes(Handle<JSReceiver> object, uint32_t index);
261 
262   V8_WARN_UNUSED_RESULT static inline Maybe<PropertyAttributes>
263   GetElementAttributes(Handle<JSReceiver> object, uint32_t index);
264   V8_WARN_UNUSED_RESULT static inline Maybe<PropertyAttributes>
265   GetOwnElementAttributes(Handle<JSReceiver> object, uint32_t index);
266 
267   V8_WARN_UNUSED_RESULT static Maybe<PropertyAttributes> GetPropertyAttributes(
268       LookupIterator* it);
269 
270   // Set the object's prototype (only JSReceiver and null are allowed values).
271   V8_EXPORT_PRIVATE V8_WARN_UNUSED_RESULT static Maybe<bool> SetPrototype(
272       Isolate* isolate, Handle<JSReceiver> object, Handle<Object> value,
273       bool from_javascript, ShouldThrow should_throw);
274 
275   inline static Handle<Object> GetDataProperty(Isolate* isolate,
276                                                Handle<JSReceiver> object,
277                                                Handle<Name> name);
278   V8_EXPORT_PRIVATE static Handle<Object> GetDataProperty(
279       LookupIterator* it, AllocationPolicy allocation_policy =
280                               AllocationPolicy::kAllocationAllowed);
281 
282   // Retrieves a permanent object identity hash code. The undefined value might
283   // be returned in case no hash was created yet.
284   V8_EXPORT_PRIVATE Object GetIdentityHash();
285 
286   // Retrieves a permanent object identity hash code. May create and store a
287   // hash code if needed and none exists.
288   static Smi CreateIdentityHash(Isolate* isolate, JSReceiver key);
289   V8_EXPORT_PRIVATE Smi GetOrCreateIdentityHash(Isolate* isolate);
290 
291   // Stores the hash code. The hash passed in must be masked with
292   // JSReceiver::kHashMask.
293   V8_EXPORT_PRIVATE void SetIdentityHash(int masked_hash);
294 
295   // ES6 [[OwnPropertyKeys]] (modulo return type)
296   V8_WARN_UNUSED_RESULT static inline MaybeHandle<FixedArray> OwnPropertyKeys(
297       Handle<JSReceiver> object);
298 
299   V8_WARN_UNUSED_RESULT static MaybeHandle<FixedArray> GetOwnValues(
300       Handle<JSReceiver> object, PropertyFilter filter,
301       bool try_fast_path = true);
302 
303   V8_WARN_UNUSED_RESULT static MaybeHandle<FixedArray> GetOwnEntries(
304       Handle<JSReceiver> object, PropertyFilter filter,
305       bool try_fast_path = true);
306 
307   static const int kHashMask = PropertyArray::HashField::kMask;
308 
309   bool HasProxyInPrototype(Isolate* isolate);
310 
311   // TC39 "Dynamic Code Brand Checks"
312   bool IsCodeLike(Isolate* isolate) const;
313 
314  private:
315   // Hide generated accessors; custom accessors are called
316   // "raw_properties_or_hash".
317   DECL_ACCESSORS(properties_or_hash, Object)
318 
319   TQ_OBJECT_CONSTRUCTORS(JSReceiver)
320 };
321 
322 // The JSObject describes real heap allocated JavaScript objects with
323 // properties.
324 // Note that the map of JSObject changes during execution to enable inline
325 // caching.
326 class JSObject : public TorqueGeneratedJSObject<JSObject, JSReceiver> {
327  public:
328   static bool IsUnmodifiedApiObject(FullObjectSlot o);
329 
330   V8_EXPORT_PRIVATE static V8_WARN_UNUSED_RESULT MaybeHandle<JSObject> New(
331       Handle<JSFunction> constructor, Handle<JSReceiver> new_target,
332       Handle<AllocationSite> site);
333 
334   // 9.1.12 ObjectCreate ( proto [ , internalSlotsList ] )
335   // Notice: This is NOT 19.1.2.2 Object.create ( O, Properties )
336   static V8_WARN_UNUSED_RESULT MaybeHandle<JSObject> ObjectCreate(
337       Isolate* isolate, Handle<Object> prototype);
338 
339   DECL_ACCESSORS(elements, FixedArrayBase)
340   DECL_RELAXED_GETTER(elements, FixedArrayBase)
341 
342   // Acquire/release semantics on this field are explicitly forbidden to avoid
343   // confusion, since the default setter uses relaxed semantics. If
344   // acquire/release semantics ever become necessary, the default setter should
345   // be reverted to non-atomic behavior, and setters with explicit tags
346   // introduced and used when required.
347   FixedArrayBase elements(PtrComprCageBase cage_base,
348                           AcquireLoadTag tag) const = delete;
349   void set_elements(FixedArrayBase value, ReleaseStoreTag tag,
350                     WriteBarrierMode mode = UPDATE_WRITE_BARRIER) = delete;
351 
352   inline void initialize_elements();
353   static inline void SetMapAndElements(Handle<JSObject> object, Handle<Map> map,
354                                        Handle<FixedArrayBase> elements);
355   DECL_GETTER(GetElementsKind, ElementsKind)
356   DECL_GETTER(GetElementsAccessor, ElementsAccessor*)
357 
358   // Returns true if an object has elements of PACKED_SMI_ELEMENTS or
359   // HOLEY_SMI_ELEMENTS ElementsKind.
360   DECL_GETTER(HasSmiElements, bool)
361   // Returns true if an object has elements of PACKED_ELEMENTS or
362   // HOLEY_ELEMENTS ElementsKind.
363   DECL_GETTER(HasObjectElements, bool)
364   // Returns true if an object has elements of PACKED_SMI_ELEMENTS,
365   // HOLEY_SMI_ELEMENTS, PACKED_ELEMENTS, or HOLEY_ELEMENTS.
366   DECL_GETTER(HasSmiOrObjectElements, bool)
367   // Returns true if an object has any of the "fast" elements kinds.
368   DECL_GETTER(HasFastElements, bool)
369   // Returns true if an object has any of the PACKED elements kinds.
370   DECL_GETTER(HasFastPackedElements, bool)
371   // Returns true if an object has elements of PACKED_DOUBLE_ELEMENTS or
372   // HOLEY_DOUBLE_ELEMENTS ElementsKind.
373   DECL_GETTER(HasDoubleElements, bool)
374   // Returns true if an object has elements of HOLEY_SMI_ELEMENTS,
375   // HOLEY_DOUBLE_ELEMENTS, or HOLEY_ELEMENTS ElementsKind.
376   DECL_GETTER(HasHoleyElements, bool)
377   DECL_GETTER(HasSloppyArgumentsElements, bool)
378   DECL_GETTER(HasStringWrapperElements, bool)
379   DECL_GETTER(HasDictionaryElements, bool)
380 
381   // Returns true if an object has elements of PACKED_ELEMENTS
382   DECL_GETTER(HasPackedElements, bool)
383   DECL_GETTER(HasAnyNonextensibleElements, bool)
384   DECL_GETTER(HasSealedElements, bool)
385   DECL_GETTER(HasNonextensibleElements, bool)
386 
387   DECL_GETTER(HasTypedArrayOrRabGsabTypedArrayElements, bool)
388 
389   DECL_GETTER(HasFixedUint8ClampedElements, bool)
390   DECL_GETTER(HasFixedArrayElements, bool)
391   DECL_GETTER(HasFixedInt8Elements, bool)
392   DECL_GETTER(HasFixedUint8Elements, bool)
393   DECL_GETTER(HasFixedInt16Elements, bool)
394   DECL_GETTER(HasFixedUint16Elements, bool)
395   DECL_GETTER(HasFixedInt32Elements, bool)
396   DECL_GETTER(HasFixedUint32Elements, bool)
397   DECL_GETTER(HasFixedFloat32Elements, bool)
398   DECL_GETTER(HasFixedFloat64Elements, bool)
399   DECL_GETTER(HasFixedBigInt64Elements, bool)
400   DECL_GETTER(HasFixedBigUint64Elements, bool)
401 
402   DECL_GETTER(HasFastArgumentsElements, bool)
403   DECL_GETTER(HasSlowArgumentsElements, bool)
404   DECL_GETTER(HasFastStringWrapperElements, bool)
405   DECL_GETTER(HasSlowStringWrapperElements, bool)
406   bool HasEnumerableElements();
407 
408   // Gets slow elements.
409   DECL_GETTER(element_dictionary, NumberDictionary)
410 
411   // Requires: HasFastElements().
412   static void EnsureWritableFastElements(Handle<JSObject> object);
413 
414   V8_WARN_UNUSED_RESULT static Maybe<bool> SetPropertyWithInterceptor(
415       LookupIterator* it, Maybe<ShouldThrow> should_throw,
416       Handle<Object> value);
417 
418   // The API currently still wants DefineOwnPropertyIgnoreAttributes to convert
419   // AccessorInfo objects to data fields. We allow FORCE_FIELD as an exception
420   // to the default behavior that calls the setter.
421   enum AccessorInfoHandling { FORCE_FIELD, DONT_FORCE_FIELD };
422 
423   V8_WARN_UNUSED_RESULT static MaybeHandle<Object>
424   DefineOwnPropertyIgnoreAttributes(
425       LookupIterator* it, Handle<Object> value, PropertyAttributes attributes,
426       AccessorInfoHandling handling = DONT_FORCE_FIELD,
427       EnforceDefineSemantics semantics = EnforceDefineSemantics::kSet);
428 
429   V8_WARN_UNUSED_RESULT static Maybe<bool> DefineOwnPropertyIgnoreAttributes(
430       LookupIterator* it, Handle<Object> value, PropertyAttributes attributes,
431       Maybe<ShouldThrow> should_throw,
432       AccessorInfoHandling handling = DONT_FORCE_FIELD,
433       EnforceDefineSemantics semantics = EnforceDefineSemantics::kSet,
434       StoreOrigin store_origin = StoreOrigin::kNamed);
435 
436   V8_WARN_UNUSED_RESULT static MaybeHandle<Object> V8_EXPORT_PRIVATE
437   SetOwnPropertyIgnoreAttributes(Handle<JSObject> object, Handle<Name> name,
438                                  Handle<Object> value,
439                                  PropertyAttributes attributes);
440 
441   V8_WARN_UNUSED_RESULT static MaybeHandle<Object>
442   SetOwnElementIgnoreAttributes(Handle<JSObject> object, size_t index,
443                                 Handle<Object> value,
444                                 PropertyAttributes attributes);
445 
446   // Equivalent to one of the above depending on whether |name| can be converted
447   // to an array index.
448   V8_EXPORT_PRIVATE V8_WARN_UNUSED_RESULT static MaybeHandle<Object>
449   DefinePropertyOrElementIgnoreAttributes(Handle<JSObject> object,
450                                           Handle<Name> name,
451                                           Handle<Object> value,
452                                           PropertyAttributes attributes = NONE);
453 
454   // Adds or reconfigures a property to attributes NONE. It will fail when it
455   // cannot.
456   V8_WARN_UNUSED_RESULT static Maybe<bool> CreateDataProperty(
457       LookupIterator* it, Handle<Object> value,
458       Maybe<ShouldThrow> should_throw = Just(kDontThrow));
459 
460   V8_EXPORT_PRIVATE static void AddProperty(Isolate* isolate,
461                                             Handle<JSObject> object,
462                                             Handle<Name> name,
463                                             Handle<Object> value,
464                                             PropertyAttributes attributes);
465 
466   // {name} must be a UTF-8 encoded, null-terminated string.
467   static void AddProperty(Isolate* isolate, Handle<JSObject> object,
468                           const char* name, Handle<Object> value,
469                           PropertyAttributes attributes);
470 
471   V8_EXPORT_PRIVATE static Maybe<bool> AddDataElement(
472       Handle<JSObject> receiver, uint32_t index, Handle<Object> value,
473       PropertyAttributes attributes);
474 
475   // Extend the receiver with a single fast property appeared first in the
476   // passed map. This also extends the property backing store if necessary.
477   static void AllocateStorageForMap(Handle<JSObject> object, Handle<Map> map);
478 
479   // Migrates the given object to a map whose field representations are the
480   // lowest upper bound of all known representations for that field.
481   static void MigrateInstance(Isolate* isolate, Handle<JSObject> instance);
482 
483   // Migrates the given object only if the target map is already available,
484   // or returns false if such a map is not yet available.
485   static bool TryMigrateInstance(Isolate* isolate, Handle<JSObject> instance);
486 
487   // Sets the property value in a normalized object given (key, value, details).
488   // Handles the special representation of JS global objects.
489   static void SetNormalizedProperty(Handle<JSObject> object, Handle<Name> name,
490                                     Handle<Object> value,
491                                     PropertyDetails details);
492   static void SetNormalizedElement(Handle<JSObject> object, uint32_t index,
493                                    Handle<Object> value,
494                                    PropertyDetails details);
495 
496   static void OptimizeAsPrototype(Handle<JSObject> object,
497                                   bool enable_setup_mode = true);
498   static void ReoptimizeIfPrototype(Handle<JSObject> object);
499   static void MakePrototypesFast(Handle<Object> receiver,
500                                  WhereToStart where_to_start, Isolate* isolate);
501   static void LazyRegisterPrototypeUser(Handle<Map> user, Isolate* isolate);
502   static void UpdatePrototypeUserRegistration(Handle<Map> old_map,
503                                               Handle<Map> new_map,
504                                               Isolate* isolate);
505   static bool UnregisterPrototypeUser(Handle<Map> user, Isolate* isolate);
506   static Map InvalidatePrototypeChains(Map map);
507   static void InvalidatePrototypeValidityCell(JSGlobalObject global);
508 
509   // Updates prototype chain tracking information when an object changes its
510   // map from |old_map| to |new_map|.
511   static void NotifyMapChange(Handle<Map> old_map, Handle<Map> new_map,
512                               Isolate* isolate);
513 
514   // Utility used by many Array builtins and runtime functions
515   static inline bool PrototypeHasNoElements(Isolate* isolate, JSObject object);
516 
517   // To be passed to PrototypeUsers::Compact.
518   static void PrototypeRegistryCompactionCallback(HeapObject value,
519                                                   int old_index, int new_index);
520 
521   // Retrieve interceptors.
522   DECL_GETTER(GetNamedInterceptor, InterceptorInfo)
523   DECL_GETTER(GetIndexedInterceptor, InterceptorInfo)
524 
525   // Used from JSReceiver.
526   V8_WARN_UNUSED_RESULT static Maybe<PropertyAttributes>
527   GetPropertyAttributesWithInterceptor(LookupIterator* it);
528   V8_WARN_UNUSED_RESULT static Maybe<PropertyAttributes>
529   GetPropertyAttributesWithFailedAccessCheck(LookupIterator* it);
530 
531   // Defines an AccessorPair property on the given object.
532   V8_EXPORT_PRIVATE static MaybeHandle<Object> DefineAccessor(
533       Handle<JSObject> object, Handle<Name> name, Handle<Object> getter,
534       Handle<Object> setter, PropertyAttributes attributes);
535   static MaybeHandle<Object> DefineAccessor(LookupIterator* it,
536                                             Handle<Object> getter,
537                                             Handle<Object> setter,
538                                             PropertyAttributes attributes);
539 
540   // Defines an AccessorInfo property on the given object.
541   V8_WARN_UNUSED_RESULT static MaybeHandle<Object> SetAccessor(
542       Handle<JSObject> object, Handle<Name> name, Handle<AccessorInfo> info,
543       PropertyAttributes attributes);
544 
545   // The result must be checked first for exceptions. If there's no exception,
546   // the output parameter |done| indicates whether the interceptor has a result
547   // or not.
548   V8_WARN_UNUSED_RESULT static MaybeHandle<Object> GetPropertyWithInterceptor(
549       LookupIterator* it, bool* done);
550 
551   static void ValidateElements(JSObject object);
552 
553   // Makes sure that this object can contain HeapObject as elements.
554   static inline void EnsureCanContainHeapObjectElements(Handle<JSObject> obj);
555 
556   // Makes sure that this object can contain the specified elements.
557   // TSlot here is either ObjectSlot or FullObjectSlot.
558   template <typename TSlot>
559   static inline void EnsureCanContainElements(Handle<JSObject> object,
560                                               TSlot elements, uint32_t count,
561                                               EnsureElementsMode mode);
562   static inline void EnsureCanContainElements(Handle<JSObject> object,
563                                               Handle<FixedArrayBase> elements,
564                                               uint32_t length,
565                                               EnsureElementsMode mode);
566   static void EnsureCanContainElements(Handle<JSObject> object,
567                                        JavaScriptArguments* arguments,
568                                        uint32_t arg_count,
569                                        EnsureElementsMode mode);
570 
571   // Would we convert a fast elements array to dictionary mode given
572   // an access at key?
573   bool WouldConvertToSlowElements(uint32_t index);
574 
575   static const uint32_t kMinAddedElementsCapacity = 16;
576 
577   // Computes the new capacity when expanding the elements of a JSObject.
NewElementsCapacity(uint32_t old_capacity)578   static uint32_t NewElementsCapacity(uint32_t old_capacity) {
579     // (old_capacity + 50%) + kMinAddedElementsCapacity
580     return old_capacity + (old_capacity >> 1) + kMinAddedElementsCapacity;
581   }
582 
583   // These methods do not perform access checks!
584   template <AllocationSiteUpdateMode update_or_check =
585                 AllocationSiteUpdateMode::kUpdate>
586   static bool UpdateAllocationSite(Handle<JSObject> object,
587                                    ElementsKind to_kind);
588 
589   // Lookup interceptors are used for handling properties controlled by host
590   // objects.
591   DECL_GETTER(HasNamedInterceptor, bool)
592   DECL_GETTER(HasIndexedInterceptor, bool)
593 
594   // Support functions for v8 api (needed for correct interceptor behavior).
595   V8_WARN_UNUSED_RESULT static Maybe<bool> HasRealNamedProperty(
596       Isolate* isolate, Handle<JSObject> object, Handle<Name> name);
597   V8_WARN_UNUSED_RESULT static Maybe<bool> HasRealElementProperty(
598       Isolate* isolate, Handle<JSObject> object, uint32_t index);
599   V8_WARN_UNUSED_RESULT static Maybe<bool> HasRealNamedCallbackProperty(
600       Isolate* isolate, Handle<JSObject> object, Handle<Name> name);
601 
602   // Get the header size for a JSObject.  Used to compute the index of
603   // embedder fields as well as the number of embedder fields.
604   // The |function_has_prototype_slot| parameter is needed only for
605   // JSFunction objects.
606   static V8_EXPORT_PRIVATE int GetHeaderSize(
607       InstanceType instance_type, bool function_has_prototype_slot = false);
608   static inline int GetHeaderSize(Map map);
609 
610   static inline bool MayHaveEmbedderFields(Map map);
611   inline bool MayHaveEmbedderFields() const;
612 
613   static inline int GetEmbedderFieldsStartOffset(Map map);
614   inline int GetEmbedderFieldsStartOffset();
615 
616   static inline int GetEmbedderFieldCount(Map map);
617   inline int GetEmbedderFieldCount() const;
618   inline int GetEmbedderFieldOffset(int index);
619   inline Object GetEmbedderField(int index);
620   inline void SetEmbedderField(int index, Object value);
621   inline void SetEmbedderField(int index, Smi value);
622 
623   // Returns true if this object is an Api object which can, if unmodified, be
624   // dropped during minor GC because the embedder can recreate it again later.
625   inline bool IsDroppableApiObject() const;
626 
627   // Returns a new map with all transitions dropped from the object's current
628   // map and the ElementsKind set.
629   static Handle<Map> GetElementsTransitionMap(Handle<JSObject> object,
630                                               ElementsKind to_kind);
631   V8_EXPORT_PRIVATE static void TransitionElementsKind(Handle<JSObject> object,
632                                                        ElementsKind to_kind);
633 
634   // Always use this to migrate an object to a new map.
635   // |expected_additional_properties| is only used for fast-to-slow transitions
636   // and ignored otherwise.
637   V8_EXPORT_PRIVATE static void MigrateToMap(
638       Isolate* isolate, Handle<JSObject> object, Handle<Map> new_map,
639       int expected_additional_properties = 0);
640 
641   // Forces a prototype without any of the checks that the regular SetPrototype
642   // would do.
643   static void ForceSetPrototype(Isolate* isolate, Handle<JSObject> object,
644                                 Handle<HeapObject> proto);
645 
646   // Convert the object to use the canonical dictionary
647   // representation. If the object is expected to have additional properties
648   // added this number can be indicated to have the backing store allocated to
649   // an initial capacity for holding these properties.
650   V8_EXPORT_PRIVATE static void NormalizeProperties(
651       Isolate* isolate, Handle<JSObject> object, PropertyNormalizationMode mode,
652       int expected_additional_properties, const char* reason);
653 
654   // Convert and update the elements backing store to be a
655   // NumberDictionary dictionary.  Returns the backing after conversion.
656   V8_EXPORT_PRIVATE static Handle<NumberDictionary> NormalizeElements(
657       Handle<JSObject> object);
658 
659   void RequireSlowElements(NumberDictionary dictionary);
660 
661   // Transform slow named properties to fast variants.
662   V8_EXPORT_PRIVATE static void MigrateSlowToFast(Handle<JSObject> object,
663                                                   int unused_property_fields,
664                                                   const char* reason);
665 
666   // Access property in dictionary mode object at the given dictionary index.
667   static Handle<Object> DictionaryPropertyAt(Isolate* isolate,
668                                              Handle<JSObject> object,
669                                              InternalIndex dict_index);
670   // Same as above, but it will return {} if we would be reading out of the
671   // bounds of the object or if the dictionary is pending allocation. Use this
672   // version for concurrent access.
673   static base::Optional<Object> DictionaryPropertyAt(Handle<JSObject> object,
674                                                      InternalIndex dict_index,
675                                                      Heap* heap);
676 
677   // Access fast-case object properties at index.
678   static Handle<Object> FastPropertyAt(Isolate* isolate,
679                                        Handle<JSObject> object,
680                                        Representation representation,
681                                        FieldIndex index);
682   static Handle<Object> FastPropertyAt(Isolate* isolate,
683                                        Handle<JSObject> object,
684                                        Representation representation,
685                                        FieldIndex index, SeqCstAccessTag tag);
686   inline Object RawFastPropertyAt(FieldIndex index) const;
687   inline Object RawFastPropertyAt(PtrComprCageBase cage_base,
688                                   FieldIndex index) const;
689   inline Object RawFastPropertyAt(FieldIndex index, SeqCstAccessTag tag) const;
690   inline Object RawFastPropertyAt(PtrComprCageBase cage_base, FieldIndex index,
691                                   SeqCstAccessTag tag) const;
692 
693   // See comment in the body of the method to understand the conditions
694   // in which this method is meant to be used, and what guarantees it
695   // provides against invalid reads from another thread during object
696   // mutation.
697   inline base::Optional<Object> RawInobjectPropertyAt(
698       PtrComprCageBase cage_base, Map original_map, FieldIndex index) const;
699 
700   inline void FastPropertyAtPut(FieldIndex index, Object value,
701                                 WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
702   inline void FastPropertyAtPut(FieldIndex index, Object value,
703                                 SeqCstAccessTag tag);
704   inline void RawFastInobjectPropertyAtPut(
705       FieldIndex index, Object value,
706       WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
707   inline void RawFastInobjectPropertyAtPut(FieldIndex index, Object value,
708                                            SeqCstAccessTag tag);
709   inline void WriteToField(InternalIndex descriptor, PropertyDetails details,
710                            Object value);
711 
712   inline Object RawFastPropertyAtSwap(FieldIndex index, Object value,
713                                       SeqCstAccessTag tag);
714   inline Object RawFastPropertyAtSwap(PtrComprCageBase cage_base,
715                                       FieldIndex index, Object value,
716                                       SeqCstAccessTag tag);
717 
718   // Access to in object properties.
719   inline int GetInObjectPropertyOffset(int index);
720   inline Object InObjectPropertyAt(int index);
721   inline Object InObjectPropertyAtPut(
722       int index, Object value, WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
723 
724   // Set the object's prototype (only JSReceiver and null are allowed values).
725   V8_WARN_UNUSED_RESULT static Maybe<bool> SetPrototype(
726       Isolate* isolate, Handle<JSObject> object, Handle<Object> value,
727       bool from_javascript, ShouldThrow should_throw);
728 
729   // Makes the object prototype immutable
730   // Never called from JavaScript
731   static void SetImmutableProto(Handle<JSObject> object);
732 
733   // Initializes the body starting at |start_offset|. It is responsibility of
734   // the caller to initialize object header. Fill the pre-allocated fields with
735   // undefined_value and the rest with filler_map.
736   // Note: this call does not update write barrier, the caller is responsible
737   // to ensure that |filler_map| can be collected without WB here.
738   inline void InitializeBody(Map map, int start_offset,
739                              bool is_slack_tracking_in_progress,
740                              MapWord filler_map, Object undefined_value);
741 
742   // Check whether this object references another object
743   bool ReferencesObject(Object obj);
744 
745   V8_WARN_UNUSED_RESULT static Maybe<bool> TestIntegrityLevel(
746       Handle<JSObject> object, IntegrityLevel lvl);
747 
748   V8_WARN_UNUSED_RESULT static Maybe<bool> PreventExtensions(
749       Handle<JSObject> object, ShouldThrow should_throw);
750 
751   static bool IsExtensible(Handle<JSObject> object);
752 
753   static MaybeHandle<Object> ReadFromOptionsBag(Handle<Object> options,
754                                                 Handle<String> option_name,
755                                                 Isolate* isolate);
756 
757   // Dispatched behavior.
758   void JSObjectShortPrint(StringStream* accumulator);
759   DECL_PRINTER(JSObject)
760   DECL_VERIFIER(JSObject)
761 #ifdef OBJECT_PRINT
762   bool PrintProperties(std::ostream& os);
763   void PrintElements(std::ostream& os);
764 #endif
765 #if defined(DEBUG) || defined(OBJECT_PRINT)
766   void PrintTransitions(std::ostream& os);
767 #endif
768 
769   static void PrintElementsTransition(FILE* file, Handle<JSObject> object,
770                                       ElementsKind from_kind,
771                                       Handle<FixedArrayBase> from_elements,
772                                       ElementsKind to_kind,
773                                       Handle<FixedArrayBase> to_elements);
774 
775   void PrintInstanceMigration(FILE* file, Map original_map, Map new_map);
776 
777 #ifdef DEBUG
778   // Structure for collecting spill information about JSObjects.
779   class SpillInformation {
780    public:
781     void Clear();
782     void Print();
783     int number_of_objects_;
784     int number_of_objects_with_fast_properties_;
785     int number_of_objects_with_fast_elements_;
786     int number_of_fast_used_fields_;
787     int number_of_fast_unused_fields_;
788     int number_of_slow_used_properties_;
789     int number_of_slow_unused_properties_;
790     int number_of_fast_used_elements_;
791     int number_of_fast_unused_elements_;
792     int number_of_slow_used_elements_;
793     int number_of_slow_unused_elements_;
794   };
795 
796   void IncrementSpillStatistics(Isolate* isolate, SpillInformation* info);
797 #endif
798 
799 #ifdef VERIFY_HEAP
800   // If a GC was caused while constructing this object, the elements pointer
801   // may point to a one pointer filler map. The object won't be rooted, but
802   // our heap verification code could stumble across it.
803   V8_EXPORT_PRIVATE bool ElementsAreSafeToExamine(
804       PtrComprCageBase cage_base) const;
805 #endif
806 
807   Object SlowReverseLookup(Object value);
808 
809   // Maximal number of elements (numbered 0 .. kMaxElementCount - 1).
810   // Also maximal value of JSArray's length property.
811   static constexpr uint32_t kMaxElementCount = kMaxUInt32;
812   static constexpr uint32_t kMaxElementIndex = kMaxElementCount - 1;
813 
814   // Constants for heuristics controlling conversion of fast elements
815   // to slow elements.
816 
817   // Maximal gap that can be introduced by adding an element beyond
818   // the current elements length.
819   static const uint32_t kMaxGap = 1024;
820 
821   // Maximal length of fast elements array that won't be checked for
822   // being dense enough on expansion.
823   static const int kMaxUncheckedFastElementsLength = 5000;
824 
825   // Same as above but for old arrays. This limit is more strict. We
826   // don't want to be wasteful with long lived objects.
827   static const int kMaxUncheckedOldFastElementsLength = 500;
828 
829   // This constant applies only to the initial map of "global.Object" and
830   // not to arbitrary other JSObject maps.
831   static const int kInitialGlobalObjectUnusedPropertiesCount = 4;
832 
833   static const int kMaxInstanceSize = 255 * kTaggedSize;
834 
835   static const int kMapCacheSize = 128;
836 
837   // When extending the backing storage for property values, we increase
838   // its size by more than the 1 entry necessary, so sequentially adding fields
839   // to the same object requires fewer allocations and copies.
840   static const int kFieldsAdded = 3;
841   STATIC_ASSERT(kMaxNumberOfDescriptors + kFieldsAdded <=
842                 PropertyArray::kMaxLength);
843 
844   STATIC_ASSERT(kHeaderSize == Internals::kJSObjectHeaderSize);
845   static const int kMaxInObjectProperties =
846       (kMaxInstanceSize - kHeaderSize) >> kTaggedSizeLog2;
847   STATIC_ASSERT(kMaxInObjectProperties <= kMaxNumberOfDescriptors);
848 
849   static const int kMaxFirstInobjectPropertyOffset =
850       (1 << kFirstInobjectPropertyOffsetBitCount) - 1;
851   static const int kMaxEmbedderFields =
852       (kMaxFirstInobjectPropertyOffset - kHeaderSize) / kEmbedderDataSlotSize;
853   STATIC_ASSERT(kHeaderSize +
854                     kMaxEmbedderFields * kEmbedderDataSlotSizeInTaggedSlots <=
855                 kMaxInstanceSize);
856 
857   class BodyDescriptor;
858 
859   class FastBodyDescriptor;
860 
861   // Gets the number of currently used elements.
862   int GetFastElementsUsage();
863 
864   static bool AllCanRead(LookupIterator* it);
865   static bool AllCanWrite(LookupIterator* it);
866 
867   template <typename Dictionary>
868   static void ApplyAttributesToDictionary(Isolate* isolate, ReadOnlyRoots roots,
869                                           Handle<Dictionary> dictionary,
870                                           const PropertyAttributes attributes);
871 
872  private:
873   friend class JSReceiver;
874   friend class Object;
875 
876   // Used from Object::GetProperty().
877   V8_WARN_UNUSED_RESULT static MaybeHandle<Object>
878   GetPropertyWithFailedAccessCheck(LookupIterator* it);
879 
880   V8_WARN_UNUSED_RESULT static Maybe<bool> SetPropertyWithFailedAccessCheck(
881       LookupIterator* it, Handle<Object> value,
882       Maybe<ShouldThrow> should_throw);
883 
884   V8_WARN_UNUSED_RESULT static Maybe<bool> DeletePropertyWithInterceptor(
885       LookupIterator* it, ShouldThrow should_throw);
886 
887   bool ReferencesObjectFromElements(FixedArray elements, ElementsKind kind,
888                                     Object object);
889 
890   // Helper for fast versions of preventExtensions, seal, and freeze.
891   // attrs is one of NONE, SEALED, or FROZEN (depending on the operation).
892   template <PropertyAttributes attrs>
893   V8_WARN_UNUSED_RESULT static Maybe<bool> PreventExtensionsWithTransition(
894       Handle<JSObject> object, ShouldThrow should_throw);
895 
896   TQ_OBJECT_CONSTRUCTORS(JSObject)
897 };
898 
899 // A JSObject created through the public api which wraps an external pointer.
900 // See v8::External.
901 class JSExternalObject
902     : public TorqueGeneratedJSExternalObject<JSExternalObject, JSObject> {
903  public:
904   inline void AllocateExternalPointerEntries(Isolate* isolate);
905 
906   // [value]: field containing the pointer value.
907   DECL_GETTER(value, void*)
908 
909   inline void set_value(Isolate* isolate, void* value);
910 
911   static constexpr int kEndOfTaggedFieldsOffset = JSObject::kHeaderSize;
912 
913   class BodyDescriptor;
914 
915  private:
916   TQ_OBJECT_CONSTRUCTORS(JSExternalObject)
917 };
918 
919 // An abstract superclass for JSObjects that may contain EmbedderDataSlots.
920 class JSObjectWithEmbedderSlots
921     : public TorqueGeneratedJSObjectWithEmbedderSlots<JSObjectWithEmbedderSlots,
922                                                       JSObject> {
923  public:
924   STATIC_ASSERT(kHeaderSize == JSObject::kHeaderSize);
925   TQ_OBJECT_CONSTRUCTORS(JSObjectWithEmbedderSlots)
926 };
927 
928 // An abstract superclass for JSObjects that may have elements while having an
929 // empty fixed array as elements backing store. It doesn't carry any
930 // functionality but allows function classes to be identified in the type
931 // system.
932 class JSCustomElementsObject
933     : public TorqueGeneratedJSCustomElementsObject<JSCustomElementsObject,
934                                                    JSObject> {
935  public:
936   STATIC_ASSERT(kHeaderSize == JSObject::kHeaderSize);
937   TQ_OBJECT_CONSTRUCTORS(JSCustomElementsObject)
938 };
939 
940 // An abstract superclass for JSObjects that require non-standard element
941 // access. It doesn't carry any functionality but allows function classes to be
942 // identified in the type system.
943 // These may also contain EmbedderDataSlots, but can't currently inherit from
944 // JSObjectWithEmbedderSlots due to instance_type constraints.
945 class JSSpecialObject
946     : public TorqueGeneratedJSSpecialObject<JSSpecialObject,
947                                             JSCustomElementsObject> {
948  public:
949   STATIC_ASSERT(kHeaderSize == JSObject::kHeaderSize);
950   TQ_OBJECT_CONSTRUCTORS(JSSpecialObject)
951 };
952 
953 // JSAccessorPropertyDescriptor is just a JSObject with a specific initial
954 // map. This initial map adds in-object properties for "get", "set",
955 // "enumerable" and "configurable" properties, as assigned by the
956 // FromPropertyDescriptor function for regular accessor properties.
957 class JSAccessorPropertyDescriptor : public JSObject {
958  public:
959   // Layout description.
960 #define JS_ACCESSOR_PROPERTY_DESCRIPTOR_FIELDS(V) \
961   V(kGetOffset, kTaggedSize)                      \
962   V(kSetOffset, kTaggedSize)                      \
963   V(kEnumerableOffset, kTaggedSize)               \
964   V(kConfigurableOffset, kTaggedSize)             \
965   /* Total size. */                               \
966   V(kSize, 0)
967 
968   DEFINE_FIELD_OFFSET_CONSTANTS(JSObject::kHeaderSize,
969                                 JS_ACCESSOR_PROPERTY_DESCRIPTOR_FIELDS)
970 #undef JS_ACCESSOR_PROPERTY_DESCRIPTOR_FIELDS
971 
972   // Indices of in-object properties.
973   static const int kGetIndex = 0;
974   static const int kSetIndex = 1;
975   static const int kEnumerableIndex = 2;
976   static const int kConfigurableIndex = 3;
977 
978  private:
979   DISALLOW_IMPLICIT_CONSTRUCTORS(JSAccessorPropertyDescriptor);
980 };
981 
982 // JSDataPropertyDescriptor is just a JSObject with a specific initial map.
983 // This initial map adds in-object properties for "value", "writable",
984 // "enumerable" and "configurable" properties, as assigned by the
985 // FromPropertyDescriptor function for regular data properties.
986 class JSDataPropertyDescriptor : public JSObject {
987  public:
988   // Layout description.
989 #define JS_DATA_PROPERTY_DESCRIPTOR_FIELDS(V) \
990   V(kValueOffset, kTaggedSize)                \
991   V(kWritableOffset, kTaggedSize)             \
992   V(kEnumerableOffset, kTaggedSize)           \
993   V(kConfigurableOffset, kTaggedSize)         \
994   /* Total size. */                           \
995   V(kSize, 0)
996 
997   DEFINE_FIELD_OFFSET_CONSTANTS(JSObject::kHeaderSize,
998                                 JS_DATA_PROPERTY_DESCRIPTOR_FIELDS)
999 #undef JS_DATA_PROPERTY_DESCRIPTOR_FIELDS
1000 
1001   // Indices of in-object properties.
1002   static const int kValueIndex = 0;
1003   static const int kWritableIndex = 1;
1004   static const int kEnumerableIndex = 2;
1005   static const int kConfigurableIndex = 3;
1006 
1007  private:
1008   DISALLOW_IMPLICIT_CONSTRUCTORS(JSDataPropertyDescriptor);
1009 };
1010 
1011 // JSIteratorResult is just a JSObject with a specific initial map.
1012 // This initial map adds in-object properties for "done" and "value",
1013 // as specified by ES6 section 25.1.1.3 The IteratorResult Interface.
1014 class JSIteratorResult : public JSObject {
1015  public:
1016   DECL_ACCESSORS(value, Object)
1017 
1018   DECL_ACCESSORS(done, Object)
1019 
1020   // Layout description.
1021 #define JS_ITERATOR_RESULT_FIELDS(V) \
1022   V(kValueOffset, kTaggedSize)       \
1023   V(kDoneOffset, kTaggedSize)        \
1024   /* Total size. */                  \
1025   V(kSize, 0)
1026 
1027   DEFINE_FIELD_OFFSET_CONSTANTS(JSObject::kHeaderSize,
1028                                 JS_ITERATOR_RESULT_FIELDS)
1029 #undef JS_ITERATOR_RESULT_FIELDS
1030 
1031   // Indices of in-object properties.
1032   static const int kValueIndex = 0;
1033   static const int kDoneIndex = 1;
1034 
1035   DECL_CAST(JSIteratorResult)
1036 
1037   OBJECT_CONSTRUCTORS(JSIteratorResult, JSObject);
1038 };
1039 
1040 // JSGlobalProxy's prototype must be a JSGlobalObject or null,
1041 // and the prototype is hidden. JSGlobalProxy always delegates
1042 // property accesses to its prototype if the prototype is not null.
1043 //
1044 // A JSGlobalProxy can be reinitialized which will preserve its identity.
1045 //
1046 // Accessing a JSGlobalProxy requires security check.
1047 
1048 class JSGlobalProxy
1049     : public TorqueGeneratedJSGlobalProxy<JSGlobalProxy, JSSpecialObject> {
1050  public:
1051   inline bool IsDetachedFrom(JSGlobalObject global) const;
1052   V8_EXPORT_PRIVATE bool IsDetached() const;
1053 
1054   static int SizeWithEmbedderFields(int embedder_field_count);
1055 
1056   // Dispatched behavior.
1057   DECL_PRINTER(JSGlobalProxy)
1058   DECL_VERIFIER(JSGlobalProxy)
1059 
1060   TQ_OBJECT_CONSTRUCTORS(JSGlobalProxy)
1061 };
1062 
1063 // JavaScript global object.
1064 class JSGlobalObject
1065     : public TorqueGeneratedJSGlobalObject<JSGlobalObject, JSSpecialObject> {
1066  public:
1067   DECL_RELEASE_ACQUIRE_ACCESSORS(global_dictionary, GlobalDictionary)
1068 
1069   static void InvalidatePropertyCell(Handle<JSGlobalObject> object,
1070                                      Handle<Name> name);
1071 
1072   inline bool IsDetached();
1073 
1074   // May be called by the concurrent GC when the global object is not
1075   // fully initialized.
1076   DECL_GETTER(native_context_unchecked, Object)
1077 
1078   // Dispatched behavior.
1079   DECL_PRINTER(JSGlobalObject)
1080   DECL_VERIFIER(JSGlobalObject)
1081 
1082   TQ_OBJECT_CONSTRUCTORS(JSGlobalObject)
1083 };
1084 
1085 // Representation for JS Wrapper objects, String, Number, Boolean, etc.
1086 class JSPrimitiveWrapper
1087     : public TorqueGeneratedJSPrimitiveWrapper<JSPrimitiveWrapper,
1088                                                JSCustomElementsObject> {
1089  public:
1090   // Dispatched behavior.
1091   DECL_PRINTER(JSPrimitiveWrapper)
1092 
1093   TQ_OBJECT_CONSTRUCTORS(JSPrimitiveWrapper)
1094 };
1095 
1096 class DateCache;
1097 
1098 // Representation for JS date objects.
1099 class JSDate : public TorqueGeneratedJSDate<JSDate, JSObject> {
1100  public:
1101   static V8_WARN_UNUSED_RESULT MaybeHandle<JSDate> New(
1102       Handle<JSFunction> constructor, Handle<JSReceiver> new_target, double tv);
1103 
1104   // Returns the time value (UTC) identifying the current time.
1105   static double CurrentTimeValue(Isolate* isolate);
1106 
1107   // Returns the date field with the specified index.
1108   // See FieldIndex for the list of date fields.
1109   // Arguments and result are raw Address values because this is called
1110   // via ExternalReference.
1111   // {raw_date} is a tagged Object pointer.
1112   // {smi_index} is a tagged Smi.
1113   // The return value is a tagged Object pointer.
1114   static Address GetField(Isolate* isolate, Address raw_date,
1115                           Address smi_index);
1116 
1117   static Handle<Object> SetValue(Handle<JSDate> date, double v);
1118 
1119   void SetValue(Object value, bool is_value_nan);
1120 
1121   // Dispatched behavior.
1122   DECL_PRINTER(JSDate)
1123   DECL_VERIFIER(JSDate)
1124 
1125   // The order is important. It must be kept in sync with date macros
1126   // in macros.py.
1127   enum FieldIndex {
1128     kDateValue,
1129     kYear,
1130     kMonth,
1131     kDay,
1132     kWeekday,
1133     kHour,
1134     kMinute,
1135     kSecond,
1136     kFirstUncachedField,
1137     kMillisecond = kFirstUncachedField,
1138     kDays,
1139     kTimeInDay,
1140     kFirstUTCField,
1141     kYearUTC = kFirstUTCField,
1142     kMonthUTC,
1143     kDayUTC,
1144     kWeekdayUTC,
1145     kHourUTC,
1146     kMinuteUTC,
1147     kSecondUTC,
1148     kMillisecondUTC,
1149     kDaysUTC,
1150     kTimeInDayUTC,
1151     kTimezoneOffset
1152   };
1153 
1154  private:
1155   Object DoGetField(Isolate* isolate, FieldIndex index);
1156   Object GetUTCField(FieldIndex index, double value, DateCache* date_cache);
1157 
1158   // Computes and caches the cacheable fields of the date.
1159   inline void SetCachedFields(int64_t local_time_ms, DateCache* date_cache);
1160 
1161   TQ_OBJECT_CONSTRUCTORS(JSDate)
1162 };
1163 
1164 // Representation of message objects used for error reporting through
1165 // the API. The messages are formatted in JavaScript so this object is
1166 // a real JavaScript object. The information used for formatting the
1167 // error messages are not directly accessible from JavaScript to
1168 // prevent leaking information to user code called during error
1169 // formatting.
1170 class JSMessageObject
1171     : public TorqueGeneratedJSMessageObject<JSMessageObject, JSObject> {
1172  public:
1173   // [type]: the type of error message.
1174   inline MessageTemplate type() const;
1175   inline void set_type(MessageTemplate value);
1176 
1177   // Initializes the source positions in the object if possible. Does nothing if
1178   // called more than once. If called when stack space is exhausted, then the
1179   // source positions will be not be set and calling it again when there is more
1180   // stack space will not have any effect.
1181   static void EnsureSourcePositionsAvailable(Isolate* isolate,
1182                                              Handle<JSMessageObject> message);
1183 
1184   // Gets the start and end positions for the message.
1185   // EnsureSourcePositionsAvailable must have been called before calling these.
1186   inline int GetStartPosition() const;
1187   inline int GetEndPosition() const;
1188 
1189   // Returns the line number for the error message (1-based), or
1190   // Message::kNoLineNumberInfo if the line cannot be determined.
1191   // EnsureSourcePositionsAvailable must have been called before calling this.
1192   V8_EXPORT_PRIVATE int GetLineNumber() const;
1193 
1194   // Returns the offset of the given position within the containing line.
1195   // EnsureSourcePositionsAvailable must have been called before calling this.
1196   V8_EXPORT_PRIVATE int GetColumnNumber() const;
1197 
1198   // Returns the source code
1199   V8_EXPORT_PRIVATE String GetSource() const;
1200 
1201   // Returns the source code line containing the given source
1202   // position, or the empty string if the position is invalid.
1203   // EnsureSourcePositionsAvailable must have been called before calling this.
1204   Handle<String> GetSourceLine() const;
1205 
1206   DECL_INT_ACCESSORS(error_level)
1207 
1208   // Dispatched behavior.
1209   DECL_PRINTER(JSMessageObject)
1210 
1211   // TODO(v8:8989): [torque] Support marker constants.
1212   static const int kPointerFieldsEndOffset = kStartPositionOffset;
1213 
1214   using BodyDescriptor =
1215       FixedBodyDescriptor<HeapObject::kMapOffset, kPointerFieldsEndOffset,
1216                           kHeaderSize>;
1217 
1218  private:
1219   friend class Factory;
1220 
1221   inline bool DidEnsureSourcePositionsAvailable() const;
1222 
1223   // [shared]: optional SharedFunctionInfo that can be used to reconstruct the
1224   // source position if not available when the message was generated.
1225   DECL_ACCESSORS(shared_info, HeapObject)
1226 
1227   // [bytecode_offset]: optional offset using along with |shared| to generation
1228   // source positions.
1229   DECL_ACCESSORS(bytecode_offset, Smi)
1230 
1231   // [start_position]: the start position in the script for the error message.
1232   DECL_INT_ACCESSORS(start_position)
1233 
1234   // [end_position]: the end position in the script for the error message.
1235   DECL_INT_ACCESSORS(end_position)
1236 
1237   DECL_INT_ACCESSORS(raw_type)
1238 
1239   // Hide generated accessors; custom accessors are named "raw_type".
1240   DECL_INT_ACCESSORS(message_type)
1241 
1242   TQ_OBJECT_CONSTRUCTORS(JSMessageObject)
1243 };
1244 
1245 // The [Async-from-Sync Iterator] object
1246 // (proposal-async-iteration/#sec-async-from-sync-iterator-objects)
1247 // An object which wraps an ordinary Iterator and converts it to behave
1248 // according to the Async Iterator protocol.
1249 // (See https://tc39.github.io/proposal-async-iteration/#sec-iteration)
1250 class JSAsyncFromSyncIterator
1251     : public TorqueGeneratedJSAsyncFromSyncIterator<JSAsyncFromSyncIterator,
1252                                                     JSObject> {
1253  public:
1254   DECL_PRINTER(JSAsyncFromSyncIterator)
1255 
1256   // Async-from-Sync Iterator instances are ordinary objects that inherit
1257   // properties from the %AsyncFromSyncIteratorPrototype% intrinsic object.
1258   // Async-from-Sync Iterator instances are initially created with the internal
1259   // slots listed in Table 4.
1260   // (proposal-async-iteration/#table-async-from-sync-iterator-internal-slots)
1261 
1262   TQ_OBJECT_CONSTRUCTORS(JSAsyncFromSyncIterator)
1263 };
1264 
1265 class JSStringIterator
1266     : public TorqueGeneratedJSStringIterator<JSStringIterator, JSObject> {
1267  public:
1268   // Dispatched behavior.
1269   DECL_PRINTER(JSStringIterator)
1270   DECL_VERIFIER(JSStringIterator)
1271 
1272   TQ_OBJECT_CONSTRUCTORS(JSStringIterator)
1273 };
1274 
1275 }  // namespace internal
1276 }  // namespace v8
1277 
1278 #include "src/objects/object-macros-undef.h"
1279 
1280 #endif  // V8_OBJECTS_JS_OBJECTS_H_
1281