1 // Copyright 2012 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.
8 #include "src/heap/heap.h"
9 #include "src/objects.h"
15 enum ContextLookupFlags {
16 FOLLOW_CONTEXT_CHAIN = 1,
17 FOLLOW_PROTOTYPE_CHAIN = 2,
19 DONT_FOLLOW_CHAINS = 0,
20 FOLLOW_CHAINS = FOLLOW_CONTEXT_CHAIN | FOLLOW_PROTOTYPE_CHAIN
24 // ES5 10.2 defines lexical environments with mutable and immutable bindings.
25 // Immutable bindings have two states, initialized and uninitialized, and
26 // their state is changed by the InitializeImmutableBinding method. The
27 // BindingFlags enum represents information if a binding has definitely been
28 // initialized. A mutable binding does not need to be checked and thus has
29 // the BindingFlag MUTABLE_IS_INITIALIZED.
31 // There are two possibilities for immutable bindings
32 // * 'const' declared variables. They are initialized when evaluating the
33 // corresponding declaration statement. They need to be checked for being
34 // initialized and thus get the flag IMMUTABLE_CHECK_INITIALIZED.
35 // * The function name of a named function literal. The binding is immediately
36 // initialized when entering the function and thus does not need to be
37 // checked. it gets the BindingFlag IMMUTABLE_IS_INITIALIZED.
38 // Accessing an uninitialized binding produces the undefined value.
40 // The harmony proposal for block scoped bindings also introduces the
41 // uninitialized state for mutable bindings.
42 // * A 'let' declared variable. They are initialized when evaluating the
43 // corresponding declaration statement. They need to be checked for being
44 // initialized and thus get the flag MUTABLE_CHECK_INITIALIZED.
45 // * A 'var' declared variable. It is initialized immediately upon creation
46 // and thus doesn't need to be checked. It gets the flag
47 // MUTABLE_IS_INITIALIZED.
48 // * Catch bound variables, function parameters and variables introduced by
49 // function declarations are initialized immediately and do not need to be
50 // checked. Thus they get the flag MUTABLE_IS_INITIALIZED.
51 // Immutable bindings in harmony mode get the _HARMONY flag variants. Accessing
52 // an uninitialized binding produces a reference error.
54 // In V8 uninitialized bindings are set to the hole value upon creation and set
55 // to a different value upon initialization.
57 MUTABLE_IS_INITIALIZED,
58 MUTABLE_CHECK_INITIALIZED,
59 IMMUTABLE_IS_INITIALIZED,
60 IMMUTABLE_CHECK_INITIALIZED,
61 IMMUTABLE_IS_INITIALIZED_HARMONY,
62 IMMUTABLE_CHECK_INITIALIZED_HARMONY,
67 // Heap-allocated activation contexts.
69 // Contexts are implemented as FixedArray objects; the Context
70 // class is a convenience interface casted on a FixedArray object.
72 // Note: Context must have no virtual functions and Context objects
73 // must always be allocated via Heap::AllocateContext() or
74 // Factory::NewContext.
76 #define NATIVE_CONTEXT_FIELDS(V) \
77 V(GLOBAL_PROXY_INDEX, JSObject, global_proxy_object) \
78 V(SECURITY_TOKEN_INDEX, Object, security_token) \
79 V(BOOLEAN_FUNCTION_INDEX, JSFunction, boolean_function) \
80 V(NUMBER_FUNCTION_INDEX, JSFunction, number_function) \
81 V(STRING_FUNCTION_INDEX, JSFunction, string_function) \
82 V(STRING_FUNCTION_PROTOTYPE_MAP_INDEX, Map, string_function_prototype_map) \
83 V(SYMBOL_FUNCTION_INDEX, JSFunction, symbol_function) \
84 V(OBJECT_FUNCTION_INDEX, JSFunction, object_function) \
85 V(INTERNAL_ARRAY_FUNCTION_INDEX, JSFunction, internal_array_function) \
86 V(ARRAY_FUNCTION_INDEX, JSFunction, array_function) \
87 V(JS_ARRAY_MAPS_INDEX, Object, js_array_maps) \
88 V(DATE_FUNCTION_INDEX, JSFunction, date_function) \
89 V(JSON_OBJECT_INDEX, JSObject, json_object) \
90 V(REGEXP_FUNCTION_INDEX, JSFunction, regexp_function) \
91 V(INITIAL_OBJECT_PROTOTYPE_INDEX, JSObject, initial_object_prototype) \
92 V(INITIAL_ARRAY_PROTOTYPE_INDEX, JSObject, initial_array_prototype) \
93 V(CREATE_DATE_FUN_INDEX, JSFunction, create_date_fun) \
94 V(TO_NUMBER_FUN_INDEX, JSFunction, to_number_fun) \
95 V(TO_STRING_FUN_INDEX, JSFunction, to_string_fun) \
96 V(TO_DETAIL_STRING_FUN_INDEX, JSFunction, to_detail_string_fun) \
97 V(TO_OBJECT_FUN_INDEX, JSFunction, to_object_fun) \
98 V(TO_INTEGER_FUN_INDEX, JSFunction, to_integer_fun) \
99 V(TO_UINT32_FUN_INDEX, JSFunction, to_uint32_fun) \
100 V(TO_INT32_FUN_INDEX, JSFunction, to_int32_fun) \
101 V(TO_LENGTH_FUN_INDEX, JSFunction, to_length_fun) \
102 V(GLOBAL_EVAL_FUN_INDEX, JSFunction, global_eval_fun) \
103 V(ARRAY_BUFFER_FUN_INDEX, JSFunction, array_buffer_fun) \
104 V(UINT8_ARRAY_FUN_INDEX, JSFunction, uint8_array_fun) \
105 V(INT8_ARRAY_FUN_INDEX, JSFunction, int8_array_fun) \
106 V(UINT16_ARRAY_FUN_INDEX, JSFunction, uint16_array_fun) \
107 V(INT16_ARRAY_FUN_INDEX, JSFunction, int16_array_fun) \
108 V(UINT32_ARRAY_FUN_INDEX, JSFunction, uint32_array_fun) \
109 V(INT32_ARRAY_FUN_INDEX, JSFunction, int32_array_fun) \
110 V(FLOAT32_ARRAY_FUN_INDEX, JSFunction, float32_array_fun) \
111 V(FLOAT64_ARRAY_FUN_INDEX, JSFunction, float64_array_fun) \
112 V(UINT8_CLAMPED_ARRAY_FUN_INDEX, JSFunction, uint8_clamped_array_fun) \
113 V(INT8_ARRAY_EXTERNAL_MAP_INDEX, Map, int8_array_external_map) \
114 V(UINT8_ARRAY_EXTERNAL_MAP_INDEX, Map, uint8_array_external_map) \
115 V(INT16_ARRAY_EXTERNAL_MAP_INDEX, Map, int16_array_external_map) \
116 V(UINT16_ARRAY_EXTERNAL_MAP_INDEX, Map, uint16_array_external_map) \
117 V(INT32_ARRAY_EXTERNAL_MAP_INDEX, Map, int32_array_external_map) \
118 V(UINT32_ARRAY_EXTERNAL_MAP_INDEX, Map, uint32_array_external_map) \
119 V(FLOAT32_ARRAY_EXTERNAL_MAP_INDEX, Map, float32_array_external_map) \
120 V(FLOAT64_ARRAY_EXTERNAL_MAP_INDEX, Map, float64_array_external_map) \
121 V(UINT8_CLAMPED_ARRAY_EXTERNAL_MAP_INDEX, Map, \
122 uint8_clamped_array_external_map) \
123 V(DATA_VIEW_FUN_INDEX, JSFunction, data_view_fun) \
124 V(SLOPPY_FUNCTION_MAP_INDEX, Map, sloppy_function_map) \
125 V(SLOPPY_FUNCTION_WITH_READONLY_PROTOTYPE_MAP_INDEX, Map, \
126 sloppy_function_with_readonly_prototype_map) \
127 V(STRICT_FUNCTION_MAP_INDEX, Map, strict_function_map) \
128 V(STRONG_FUNCTION_MAP_INDEX, Map, strong_function_map) \
129 V(SLOPPY_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, Map, \
130 sloppy_function_without_prototype_map) \
131 V(STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, Map, \
132 strict_function_without_prototype_map) \
133 V(STRONG_CONSTRUCTOR_MAP_INDEX, Map, strong_constructor_map) \
134 V(BOUND_FUNCTION_MAP_INDEX, Map, bound_function_map) \
135 V(REGEXP_RESULT_MAP_INDEX, Map, regexp_result_map) \
136 V(SLOPPY_ARGUMENTS_MAP_INDEX, Map, sloppy_arguments_map) \
137 V(ALIASED_ARGUMENTS_MAP_INDEX, Map, aliased_arguments_map) \
138 V(STRICT_ARGUMENTS_MAP_INDEX, Map, strict_arguments_map) \
139 V(MESSAGE_LISTENERS_INDEX, JSObject, message_listeners) \
140 V(MAKE_MESSAGE_FUN_INDEX, JSFunction, make_message_fun) \
141 V(GET_STACK_TRACE_LINE_INDEX, JSFunction, get_stack_trace_line_fun) \
142 V(CONFIGURE_GLOBAL_INDEX, JSFunction, configure_global_fun) \
143 V(FUNCTION_CACHE_INDEX, ObjectHashTable, function_cache) \
144 V(JSFUNCTION_RESULT_CACHES_INDEX, FixedArray, jsfunction_result_caches) \
145 V(NORMALIZED_MAP_CACHE_INDEX, Object, normalized_map_cache) \
146 V(RUNTIME_CONTEXT_INDEX, Context, runtime_context) \
147 V(CALL_AS_FUNCTION_DELEGATE_INDEX, JSFunction, call_as_function_delegate) \
148 V(CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, JSFunction, \
149 call_as_constructor_delegate) \
150 V(SCRIPT_FUNCTION_INDEX, JSFunction, script_function) \
151 V(OPAQUE_REFERENCE_FUNCTION_INDEX, JSFunction, opaque_reference_function) \
152 V(CONTEXT_EXTENSION_FUNCTION_INDEX, JSFunction, context_extension_function) \
153 V(MAP_CACHE_INDEX, Object, map_cache) \
154 V(EMBEDDER_DATA_INDEX, FixedArray, embedder_data) \
155 V(ALLOW_CODE_GEN_FROM_STRINGS_INDEX, Object, allow_code_gen_from_strings) \
156 V(ERROR_MESSAGE_FOR_CODE_GEN_FROM_STRINGS_INDEX, Object, \
157 error_message_for_code_gen_from_strings) \
158 V(PROMISE_STATUS_INDEX, Symbol, promise_status) \
159 V(PROMISE_CREATE_INDEX, JSFunction, promise_create) \
160 V(PROMISE_RESOLVE_INDEX, JSFunction, promise_resolve) \
161 V(PROMISE_REJECT_INDEX, JSFunction, promise_reject) \
162 V(PROMISE_CHAIN_INDEX, JSFunction, promise_chain) \
163 V(PROMISE_CATCH_INDEX, JSFunction, promise_catch) \
164 V(PROMISE_THEN_INDEX, JSFunction, promise_then) \
165 V(TO_COMPLETE_PROPERTY_DESCRIPTOR_INDEX, JSFunction, \
166 to_complete_property_descriptor) \
167 V(DERIVED_HAS_TRAP_INDEX, JSFunction, derived_has_trap) \
168 V(DERIVED_GET_TRAP_INDEX, JSFunction, derived_get_trap) \
169 V(DERIVED_SET_TRAP_INDEX, JSFunction, derived_set_trap) \
170 V(PROXY_ENUMERATE_INDEX, JSFunction, proxy_enumerate) \
171 V(OBSERVERS_NOTIFY_CHANGE_INDEX, JSFunction, observers_notify_change) \
172 V(OBSERVERS_ENQUEUE_SPLICE_INDEX, JSFunction, observers_enqueue_splice) \
173 V(OBSERVERS_BEGIN_SPLICE_INDEX, JSFunction, observers_begin_perform_splice) \
174 V(OBSERVERS_END_SPLICE_INDEX, JSFunction, observers_end_perform_splice) \
175 V(NATIVE_OBJECT_OBSERVE_INDEX, JSFunction, native_object_observe) \
176 V(NATIVE_OBJECT_GET_NOTIFIER_INDEX, JSFunction, native_object_get_notifier) \
177 V(NATIVE_OBJECT_NOTIFIER_PERFORM_CHANGE, JSFunction, \
178 native_object_notifier_perform_change) \
179 V(SLOPPY_GENERATOR_FUNCTION_MAP_INDEX, Map, sloppy_generator_function_map) \
180 V(STRICT_GENERATOR_FUNCTION_MAP_INDEX, Map, strict_generator_function_map) \
181 V(STRONG_GENERATOR_FUNCTION_MAP_INDEX, Map, strong_generator_function_map) \
182 V(GENERATOR_OBJECT_PROTOTYPE_MAP_INDEX, Map, generator_object_prototype_map) \
183 V(ITERATOR_RESULT_MAP_INDEX, Map, iterator_result_map) \
184 V(MAP_ITERATOR_MAP_INDEX, Map, map_iterator_map) \
185 V(SET_ITERATOR_MAP_INDEX, Map, set_iterator_map) \
186 V(ARRAY_VALUES_ITERATOR_INDEX, JSFunction, array_values_iterator) \
187 V(SCRIPT_CONTEXT_TABLE_INDEX, ScriptContextTable, script_context_table)
190 // A table of all script contexts. Every loaded top-level script with top-level
191 // lexical declarations contributes its ScriptContext into this table.
193 // The table is a fixed array, its first slot is the current used count and
194 // the subsequent slots 1..used contain ScriptContexts.
195 class ScriptContextTable : public FixedArray {
198 static ScriptContextTable* cast(Object* context) {
199 DCHECK(context->IsScriptContextTable());
200 return reinterpret_cast<ScriptContextTable*>(context);
203 struct LookupResult {
207 InitializationFlag init_flag;
208 MaybeAssignedFlag maybe_assigned_flag;
211 int used() const { return Smi::cast(get(kUsedSlot))->value(); }
213 void set_used(int used) { set(kUsedSlot, Smi::FromInt(used)); }
215 static Handle<Context> GetContext(Handle<ScriptContextTable> table, int i) {
216 DCHECK(i < table->used());
217 return Handle<Context>::cast(FixedArray::get(table, i + 1));
220 // Lookup a variable `name` in a ScriptContextTable.
221 // If it returns true, the variable is found and `result` contains
222 // valid information about its location.
223 // If it returns false, `result` is untouched.
225 static bool Lookup(Handle<ScriptContextTable> table, Handle<String> name,
226 LookupResult* result);
229 static Handle<ScriptContextTable> Extend(Handle<ScriptContextTable> table,
230 Handle<Context> script_context);
232 static int GetContextOffset(int context_index) {
233 return kFirstContextOffset + context_index * kPointerSize;
237 static const int kUsedSlot = 0;
238 static const int kFirstContextOffset =
239 FixedArray::kHeaderSize + (kUsedSlot + 1) * kPointerSize;
241 DISALLOW_IMPLICIT_CONSTRUCTORS(ScriptContextTable);
244 // JSFunctions are pairs (context, function code), sometimes also called
245 // closures. A Context object is used to represent function contexts and
246 // dynamically pushed 'with' contexts (or 'scopes' in ECMA-262 speak).
248 // At runtime, the contexts build a stack in parallel to the execution
249 // stack, with the top-most context being the current context. All contexts
250 // have the following slots:
252 // [ closure ] This is the current function. It is the same for all
253 // contexts inside a function. It provides access to the
254 // incoming context (i.e., the outer context, which may
255 // or may not become the current function's context), and
256 // it provides access to the functions code and thus it's
257 // scope information, which in turn contains the names of
258 // statically allocated context slots. The names are needed
259 // for dynamic lookups in the presence of 'with' or 'eval'.
261 // [ previous ] A pointer to the previous context. It is NULL for
262 // function contexts, and non-NULL for 'with' contexts.
263 // Used to implement the 'with' statement.
265 // [ extension ] A pointer to an extension JSObject, or NULL. Used to
266 // implement 'with' statements and dynamic declarations
267 // (through 'eval'). The object in a 'with' statement is
268 // stored in the extension slot of a 'with' context.
269 // Dynamically declared variables/functions are also added
270 // to lazily allocated extension object. Context::Lookup
271 // searches the extension object for properties.
272 // For global and block contexts, contains the respective
274 // For module contexts, points back to the respective JSModule.
276 // [ global_object ] A pointer to the global object. Provided for quick
277 // access to the global object from inside the code (since
278 // we always have a context pointer).
280 // In addition, function contexts may have statically allocated context slots
281 // to store local variables/functions that are accessed from inner functions
282 // (via static context addresses) or through 'eval' (dynamic context lookups).
283 // The native context contains additional slots for fast access to native
286 // Finally, with Harmony scoping, the JSFunction representing a top level
287 // script will have the ScriptContext rather than a FunctionContext.
288 // Script contexts from all top-level scripts are gathered in
289 // ScriptContextTable.
291 class Context: public FixedArray {
294 static Context* cast(Object* context) {
295 DCHECK(context->IsContext());
296 return reinterpret_cast<Context*>(context);
299 // The default context slot layout; indices are FixedArray slot indices.
301 // These slots are in all contexts.
304 // The extension slot is used for either the global object (in global
305 // contexts), eval extension object (function contexts), subject of with
306 // (with contexts), or the variable name (catch contexts), the serialized
307 // scope info (block contexts), or the module instance (module contexts).
312 // This slot holds the thrown value in catch contexts.
313 THROWN_OBJECT_INDEX = MIN_CONTEXT_SLOTS,
315 // These slots are only in native contexts.
316 GLOBAL_PROXY_INDEX = MIN_CONTEXT_SLOTS,
317 SECURITY_TOKEN_INDEX,
318 SLOPPY_ARGUMENTS_MAP_INDEX,
319 ALIASED_ARGUMENTS_MAP_INDEX,
320 STRICT_ARGUMENTS_MAP_INDEX,
321 REGEXP_RESULT_MAP_INDEX,
322 SLOPPY_FUNCTION_MAP_INDEX,
323 SLOPPY_FUNCTION_WITH_READONLY_PROTOTYPE_MAP_INDEX,
324 STRICT_FUNCTION_MAP_INDEX,
325 STRONG_FUNCTION_MAP_INDEX,
326 SLOPPY_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX,
327 STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX,
328 STRONG_CONSTRUCTOR_MAP_INDEX,
329 BOUND_FUNCTION_MAP_INDEX,
330 INITIAL_OBJECT_PROTOTYPE_INDEX,
331 INITIAL_ARRAY_PROTOTYPE_INDEX,
332 BOOLEAN_FUNCTION_INDEX,
333 NUMBER_FUNCTION_INDEX,
334 STRING_FUNCTION_INDEX,
335 STRING_FUNCTION_PROTOTYPE_MAP_INDEX,
336 SYMBOL_FUNCTION_INDEX,
337 OBJECT_FUNCTION_INDEX,
338 INTERNAL_ARRAY_FUNCTION_INDEX,
339 ARRAY_FUNCTION_INDEX,
343 REGEXP_FUNCTION_INDEX,
344 CREATE_DATE_FUN_INDEX,
347 TO_DETAIL_STRING_FUN_INDEX,
349 TO_INTEGER_FUN_INDEX,
352 TO_BOOLEAN_FUN_INDEX,
353 GLOBAL_EVAL_FUN_INDEX,
354 ARRAY_BUFFER_FUN_INDEX,
355 UINT8_ARRAY_FUN_INDEX,
356 INT8_ARRAY_FUN_INDEX,
357 UINT16_ARRAY_FUN_INDEX,
358 INT16_ARRAY_FUN_INDEX,
359 UINT32_ARRAY_FUN_INDEX,
360 INT32_ARRAY_FUN_INDEX,
361 FLOAT32_ARRAY_FUN_INDEX,
362 FLOAT64_ARRAY_FUN_INDEX,
363 UINT8_CLAMPED_ARRAY_FUN_INDEX,
364 INT8_ARRAY_EXTERNAL_MAP_INDEX,
365 UINT8_ARRAY_EXTERNAL_MAP_INDEX,
366 INT16_ARRAY_EXTERNAL_MAP_INDEX,
367 UINT16_ARRAY_EXTERNAL_MAP_INDEX,
368 INT32_ARRAY_EXTERNAL_MAP_INDEX,
369 UINT32_ARRAY_EXTERNAL_MAP_INDEX,
370 FLOAT32_ARRAY_EXTERNAL_MAP_INDEX,
371 FLOAT64_ARRAY_EXTERNAL_MAP_INDEX,
372 UINT8_CLAMPED_ARRAY_EXTERNAL_MAP_INDEX,
374 MESSAGE_LISTENERS_INDEX,
375 MAKE_MESSAGE_FUN_INDEX,
376 GET_STACK_TRACE_LINE_INDEX,
377 CONFIGURE_GLOBAL_INDEX,
378 FUNCTION_CACHE_INDEX,
379 JSFUNCTION_RESULT_CACHES_INDEX,
380 NORMALIZED_MAP_CACHE_INDEX,
381 RUNTIME_CONTEXT_INDEX,
382 CALL_AS_FUNCTION_DELEGATE_INDEX,
383 CALL_AS_CONSTRUCTOR_DELEGATE_INDEX,
384 SCRIPT_FUNCTION_INDEX,
385 OPAQUE_REFERENCE_FUNCTION_INDEX,
386 CONTEXT_EXTENSION_FUNCTION_INDEX,
389 ALLOW_CODE_GEN_FROM_STRINGS_INDEX,
390 ERROR_MESSAGE_FOR_CODE_GEN_FROM_STRINGS_INDEX,
391 RUN_MICROTASKS_INDEX,
392 ENQUEUE_MICROTASK_INDEX,
393 PROMISE_STATUS_INDEX,
394 PROMISE_CREATE_INDEX,
395 PROMISE_RESOLVE_INDEX,
396 PROMISE_REJECT_INDEX,
400 TO_COMPLETE_PROPERTY_DESCRIPTOR_INDEX,
401 DERIVED_HAS_TRAP_INDEX,
402 DERIVED_GET_TRAP_INDEX,
403 DERIVED_SET_TRAP_INDEX,
404 PROXY_ENUMERATE_INDEX,
405 OBSERVERS_NOTIFY_CHANGE_INDEX,
406 OBSERVERS_ENQUEUE_SPLICE_INDEX,
407 OBSERVERS_BEGIN_SPLICE_INDEX,
408 OBSERVERS_END_SPLICE_INDEX,
409 NATIVE_OBJECT_OBSERVE_INDEX,
410 NATIVE_OBJECT_GET_NOTIFIER_INDEX,
411 NATIVE_OBJECT_NOTIFIER_PERFORM_CHANGE,
412 SLOPPY_GENERATOR_FUNCTION_MAP_INDEX,
413 STRICT_GENERATOR_FUNCTION_MAP_INDEX,
414 STRONG_GENERATOR_FUNCTION_MAP_INDEX,
415 GENERATOR_OBJECT_PROTOTYPE_MAP_INDEX,
416 ITERATOR_RESULT_MAP_INDEX,
417 MAP_ITERATOR_MAP_INDEX,
418 SET_ITERATOR_MAP_INDEX,
419 ARRAY_VALUES_ITERATOR_INDEX,
420 SCRIPT_CONTEXT_TABLE_INDEX,
424 // Properties from here are treated as weak references by the full GC.
425 // Scavenge treats them as strong references.
426 OPTIMIZED_FUNCTIONS_LIST, // Weak.
427 OPTIMIZED_CODE_LIST, // Weak.
428 DEOPTIMIZED_CODE_LIST, // Weak.
429 NEXT_CONTEXT_LINK, // Weak.
431 // Total number of slots.
432 NATIVE_CONTEXT_SLOTS,
433 FIRST_WEAK_SLOT = OPTIMIZED_FUNCTIONS_LIST
436 // Direct slot access.
437 JSFunction* closure() { return JSFunction::cast(get(CLOSURE_INDEX)); }
438 void set_closure(JSFunction* closure) { set(CLOSURE_INDEX, closure); }
440 Context* previous() {
441 Object* result = unchecked_previous();
442 DCHECK(IsBootstrappingOrValidParentContext(result, this));
443 return reinterpret_cast<Context*>(result);
445 void set_previous(Context* context) { set(PREVIOUS_INDEX, context); }
447 bool has_extension() { return extension() != NULL; }
448 Object* extension() { return get(EXTENSION_INDEX); }
449 void set_extension(Object* object) { set(EXTENSION_INDEX, object); }
451 JSModule* module() { return JSModule::cast(get(EXTENSION_INDEX)); }
452 void set_module(JSModule* module) { set(EXTENSION_INDEX, module); }
454 // Get the context where var declarations will be hoisted to, which
455 // may be the context itself.
456 Context* declaration_context();
458 GlobalObject* global_object() {
459 Object* result = get(GLOBAL_OBJECT_INDEX);
460 DCHECK(IsBootstrappingOrGlobalObject(this->GetIsolate(), result));
461 return reinterpret_cast<GlobalObject*>(result);
463 void set_global_object(GlobalObject* object) {
464 set(GLOBAL_OBJECT_INDEX, object);
467 // Returns a JSGlobalProxy object or null.
468 JSObject* global_proxy();
469 void set_global_proxy(JSObject* global);
471 // The builtins object.
472 JSBuiltinsObject* builtins();
474 // Get the script context by traversing the context chain.
475 Context* script_context();
477 // Compute the native context by traversing the context chain.
478 Context* native_context();
480 // Predicates for context types. IsNativeContext is also defined on Object
481 // because we frequently have to know if arbitrary objects are natives
483 bool IsNativeContext() {
484 Map* map = this->map();
485 return map == map->GetHeap()->native_context_map();
487 bool IsFunctionContext() {
488 Map* map = this->map();
489 return map == map->GetHeap()->function_context_map();
491 bool IsCatchContext() {
492 Map* map = this->map();
493 return map == map->GetHeap()->catch_context_map();
495 bool IsWithContext() {
496 Map* map = this->map();
497 return map == map->GetHeap()->with_context_map();
499 bool IsBlockContext() {
500 Map* map = this->map();
501 return map == map->GetHeap()->block_context_map();
503 bool IsModuleContext() {
504 Map* map = this->map();
505 return map == map->GetHeap()->module_context_map();
507 bool IsScriptContext() {
508 Map* map = this->map();
509 return map == map->GetHeap()->script_context_map();
512 bool HasSameSecurityTokenAs(Context* that) {
513 return this->global_object()->native_context()->security_token() ==
514 that->global_object()->native_context()->security_token();
517 // A native context holds a list of all functions with optimized code.
518 void AddOptimizedFunction(JSFunction* function);
519 void RemoveOptimizedFunction(JSFunction* function);
520 void SetOptimizedFunctionsListHead(Object* head);
521 Object* OptimizedFunctionsListHead();
523 // The native context also stores a list of all optimized code and a
524 // list of all deoptimized code, which are needed by the deoptimizer.
525 void AddOptimizedCode(Code* code);
526 void SetOptimizedCodeListHead(Object* head);
527 Object* OptimizedCodeListHead();
528 void SetDeoptimizedCodeListHead(Object* head);
529 Object* DeoptimizedCodeListHead();
531 Handle<Object> ErrorMessageForCodeGenerationFromStrings();
533 #define NATIVE_CONTEXT_FIELD_ACCESSORS(index, type, name) \
534 void set_##name(type* value) { \
535 DCHECK(IsNativeContext()); \
538 bool is_##name(type* value) { \
539 DCHECK(IsNativeContext()); \
540 return type::cast(get(index)) == value; \
543 DCHECK(IsNativeContext()); \
544 return type::cast(get(index)); \
546 NATIVE_CONTEXT_FIELDS(NATIVE_CONTEXT_FIELD_ACCESSORS)
547 #undef NATIVE_CONTEXT_FIELD_ACCESSORS
549 // Lookup the slot called name, starting with the current context.
550 // There are three possibilities:
552 // 1) result->IsContext():
553 // The binding was found in a context. *index is always the
554 // non-negative slot index. *attributes is NONE for var and let
555 // declarations, READ_ONLY for const declarations (never ABSENT).
557 // 2) result->IsJSObject():
558 // The binding was found as a named property in a context extension
559 // object (i.e., was introduced via eval), as a property on the subject
560 // of with, or as a property of the global object. *index is -1 and
561 // *attributes is not ABSENT.
563 // 3) result.is_null():
564 // There was no binding found, *index is always -1 and *attributes is
566 Handle<Object> Lookup(Handle<String> name,
567 ContextLookupFlags flags,
569 PropertyAttributes* attributes,
570 BindingFlags* binding_flags);
572 // Code generation support.
573 static int SlotOffset(int index) {
574 return kHeaderSize + index * kPointerSize - kHeapObjectTag;
577 static int FunctionMapIndex(LanguageMode language_mode, FunctionKind kind) {
578 if (IsGeneratorFunction(kind)) {
579 return is_strong(language_mode) ? STRONG_GENERATOR_FUNCTION_MAP_INDEX :
580 is_strict(language_mode) ? STRICT_GENERATOR_FUNCTION_MAP_INDEX
581 : SLOPPY_GENERATOR_FUNCTION_MAP_INDEX;
584 if (IsConstructor(kind)) {
585 return is_strong(language_mode) ? STRONG_CONSTRUCTOR_MAP_INDEX :
586 is_strict(language_mode) ? STRICT_FUNCTION_MAP_INDEX
587 : SLOPPY_FUNCTION_MAP_INDEX;
590 if (IsArrowFunction(kind) || IsConciseMethod(kind) ||
591 IsAccessorFunction(kind)) {
592 return is_strong(language_mode) ? STRONG_FUNCTION_MAP_INDEX :
593 is_strict(language_mode) ?
594 STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX :
595 SLOPPY_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX;
598 return is_strong(language_mode) ? STRONG_FUNCTION_MAP_INDEX :
599 is_strict(language_mode) ? STRICT_FUNCTION_MAP_INDEX
600 : SLOPPY_FUNCTION_MAP_INDEX;
603 static const int kSize = kHeaderSize + NATIVE_CONTEXT_SLOTS * kPointerSize;
606 typedef FixedBodyDescriptor<
607 kHeaderSize, kSize, kSize> ScavengeBodyDescriptor;
609 typedef FixedBodyDescriptor<
611 kHeaderSize + FIRST_WEAK_SLOT * kPointerSize,
612 kSize> MarkCompactBodyDescriptor;
615 // Unchecked access to the slots.
616 Object* unchecked_previous() { return get(PREVIOUS_INDEX); }
619 // Bootstrapping-aware type checks.
620 static bool IsBootstrappingOrValidParentContext(Object* object, Context* kid);
621 static bool IsBootstrappingOrGlobalObject(Isolate* isolate, Object* object);
624 STATIC_ASSERT(kHeaderSize == Internals::kContextHeaderSize);
625 STATIC_ASSERT(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex);
628 } } // namespace v8::internal
630 #endif // V8_CONTEXTS_H_