1 // Copyright 2012 the V8 project authors. All rights reserved.
2 // Redistribution and use in source and binary forms, with or without
3 // modification, are permitted provided that the following conditions are
6 // * Redistributions of source code must retain the above copyright
7 // notice, this list of conditions and the following disclaimer.
8 // * Redistributions in binary form must reproduce the above
9 // copyright notice, this list of conditions and the following
10 // disclaimer in the documentation and/or other materials provided
11 // with the distribution.
12 // * Neither the name of Google Inc. nor the names of its
13 // contributors may be used to endorse or promote products derived
14 // from this software without specific prior written permission.
16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 #ifndef V8_CONTEXTS_H_
29 #define V8_CONTEXTS_H_
38 enum ContextLookupFlags {
39 FOLLOW_CONTEXT_CHAIN = 1,
40 FOLLOW_PROTOTYPE_CHAIN = 2,
42 DONT_FOLLOW_CHAINS = 0,
43 FOLLOW_CHAINS = FOLLOW_CONTEXT_CHAIN | FOLLOW_PROTOTYPE_CHAIN
47 // ES5 10.2 defines lexical environments with mutable and immutable bindings.
48 // Immutable bindings have two states, initialized and uninitialized, and
49 // their state is changed by the InitializeImmutableBinding method. The
50 // BindingFlags enum represents information if a binding has definitely been
51 // initialized. A mutable binding does not need to be checked and thus has
52 // the BindingFlag MUTABLE_IS_INITIALIZED.
54 // There are two possibilities for immutable bindings
55 // * 'const' declared variables. They are initialized when evaluating the
56 // corresponding declaration statement. They need to be checked for being
57 // initialized and thus get the flag IMMUTABLE_CHECK_INITIALIZED.
58 // * The function name of a named function literal. The binding is immediately
59 // initialized when entering the function and thus does not need to be
60 // checked. it gets the BindingFlag IMMUTABLE_IS_INITIALIZED.
61 // Accessing an uninitialized binding produces the undefined value.
63 // The harmony proposal for block scoped bindings also introduces the
64 // uninitialized state for mutable bindings.
65 // * A 'let' declared variable. They are initialized when evaluating the
66 // corresponding declaration statement. They need to be checked for being
67 // initialized and thus get the flag MUTABLE_CHECK_INITIALIZED.
68 // * A 'var' declared variable. It is initialized immediately upon creation
69 // and thus doesn't need to be checked. It gets the flag
70 // MUTABLE_IS_INITIALIZED.
71 // * Catch bound variables, function parameters and variables introduced by
72 // function declarations are initialized immediately and do not need to be
73 // checked. Thus they get the flag MUTABLE_IS_INITIALIZED.
74 // Immutable bindings in harmony mode get the _HARMONY flag variants. Accessing
75 // an uninitialized binding produces a reference error.
77 // In V8 uninitialized bindings are set to the hole value upon creation and set
78 // to a different value upon initialization.
80 MUTABLE_IS_INITIALIZED,
81 MUTABLE_CHECK_INITIALIZED,
82 IMMUTABLE_IS_INITIALIZED,
83 IMMUTABLE_CHECK_INITIALIZED,
84 IMMUTABLE_IS_INITIALIZED_HARMONY,
85 IMMUTABLE_CHECK_INITIALIZED_HARMONY,
90 // Heap-allocated activation contexts.
92 // Contexts are implemented as FixedArray objects; the Context
93 // class is a convenience interface casted on a FixedArray object.
95 // Note: Context must have no virtual functions and Context objects
96 // must always be allocated via Heap::AllocateContext() or
97 // Factory::NewContext.
99 #define NATIVE_CONTEXT_FIELDS(V) \
100 V(GLOBAL_PROXY_INDEX, JSObject, global_proxy_object) \
101 V(SECURITY_TOKEN_INDEX, Object, security_token) \
102 V(BOOLEAN_FUNCTION_INDEX, JSFunction, boolean_function) \
103 V(NUMBER_FUNCTION_INDEX, JSFunction, number_function) \
104 V(FLOAT32x4_FUNCTION_INDEX, JSFunction, float32x4_function) \
105 V(FLOAT32x4_FUNCTION_PROTOTYPE_MAP_INDEX, Map, \
106 float32x4_function_prototype_map) \
107 V(INT32x4_FUNCTION_INDEX, JSFunction, int32x4_function) \
108 V(INT32x4_FUNCTION_PROTOTYPE_MAP_INDEX, Map, \
109 int32x4_function_prototype_map) \
110 V(STRING_FUNCTION_INDEX, JSFunction, string_function) \
111 V(STRING_FUNCTION_PROTOTYPE_MAP_INDEX, Map, string_function_prototype_map) \
112 V(SYMBOL_FUNCTION_INDEX, JSFunction, symbol_function) \
113 V(OBJECT_FUNCTION_INDEX, JSFunction, object_function) \
114 V(INTERNAL_ARRAY_FUNCTION_INDEX, JSFunction, internal_array_function) \
115 V(ARRAY_FUNCTION_INDEX, JSFunction, array_function) \
116 V(JS_ARRAY_MAPS_INDEX, Object, js_array_maps) \
117 V(DATE_FUNCTION_INDEX, JSFunction, date_function) \
118 V(JSON_OBJECT_INDEX, JSObject, json_object) \
119 V(SIMD_OBJECT_INDEX, JSObject, simd_object) \
120 V(REGEXP_FUNCTION_INDEX, JSFunction, regexp_function) \
121 V(INITIAL_OBJECT_PROTOTYPE_INDEX, JSObject, initial_object_prototype) \
122 V(INITIAL_ARRAY_PROTOTYPE_INDEX, JSObject, initial_array_prototype) \
123 V(CREATE_DATE_FUN_INDEX, JSFunction, create_date_fun) \
124 V(TO_NUMBER_FUN_INDEX, JSFunction, to_number_fun) \
125 V(TO_STRING_FUN_INDEX, JSFunction, to_string_fun) \
126 V(TO_DETAIL_STRING_FUN_INDEX, JSFunction, to_detail_string_fun) \
127 V(TO_OBJECT_FUN_INDEX, JSFunction, to_object_fun) \
128 V(TO_INTEGER_FUN_INDEX, JSFunction, to_integer_fun) \
129 V(TO_UINT32_FUN_INDEX, JSFunction, to_uint32_fun) \
130 V(TO_INT32_FUN_INDEX, JSFunction, to_int32_fun) \
131 V(GLOBAL_EVAL_FUN_INDEX, JSFunction, global_eval_fun) \
132 V(INSTANTIATE_FUN_INDEX, JSFunction, instantiate_fun) \
133 V(CONFIGURE_INSTANCE_FUN_INDEX, JSFunction, configure_instance_fun) \
134 V(ARRAY_BUFFER_FUN_INDEX, JSFunction, array_buffer_fun) \
135 V(UINT8_ARRAY_FUN_INDEX, JSFunction, uint8_array_fun) \
136 V(INT8_ARRAY_FUN_INDEX, JSFunction, int8_array_fun) \
137 V(UINT16_ARRAY_FUN_INDEX, JSFunction, uint16_array_fun) \
138 V(INT16_ARRAY_FUN_INDEX, JSFunction, int16_array_fun) \
139 V(UINT32_ARRAY_FUN_INDEX, JSFunction, uint32_array_fun) \
140 V(INT32_ARRAY_FUN_INDEX, JSFunction, int32_array_fun) \
141 V(FLOAT32_ARRAY_FUN_INDEX, JSFunction, float32_array_fun) \
142 V(FLOAT64_ARRAY_FUN_INDEX, JSFunction, float64_array_fun) \
143 V(FLOAT32x4_ARRAY_FUN_INDEX, JSFunction, float32x4_array_fun) \
144 V(INT32x4_ARRAY_FUN_INDEX, JSFunction, int32x4_array_fun) \
145 V(UINT8_CLAMPED_ARRAY_FUN_INDEX, JSFunction, uint8_clamped_array_fun) \
146 V(DATA_VIEW_FUN_INDEX, JSFunction, data_view_fun) \
147 V(FUNCTION_MAP_INDEX, Map, function_map) \
148 V(STRICT_MODE_FUNCTION_MAP_INDEX, Map, strict_mode_function_map) \
149 V(FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, Map, function_without_prototype_map) \
150 V(STRICT_MODE_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, Map, \
151 strict_mode_function_without_prototype_map) \
152 V(REGEXP_RESULT_MAP_INDEX, Map, regexp_result_map)\
153 V(ARGUMENTS_BOILERPLATE_INDEX, JSObject, arguments_boilerplate) \
154 V(ALIASED_ARGUMENTS_BOILERPLATE_INDEX, JSObject, \
155 aliased_arguments_boilerplate) \
156 V(STRICT_MODE_ARGUMENTS_BOILERPLATE_INDEX, JSObject, \
157 strict_mode_arguments_boilerplate) \
158 V(MESSAGE_LISTENERS_INDEX, JSObject, message_listeners) \
159 V(MAKE_MESSAGE_FUN_INDEX, JSFunction, make_message_fun) \
160 V(GET_STACK_TRACE_LINE_INDEX, JSFunction, get_stack_trace_line_fun) \
161 V(CONFIGURE_GLOBAL_INDEX, JSFunction, configure_global_fun) \
162 V(FUNCTION_CACHE_INDEX, JSObject, function_cache) \
163 V(JSFUNCTION_RESULT_CACHES_INDEX, FixedArray, jsfunction_result_caches) \
164 V(NORMALIZED_MAP_CACHE_INDEX, NormalizedMapCache, normalized_map_cache) \
165 V(RUNTIME_CONTEXT_INDEX, Context, runtime_context) \
166 V(CALL_AS_FUNCTION_DELEGATE_INDEX, JSFunction, call_as_function_delegate) \
167 V(CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, JSFunction, \
168 call_as_constructor_delegate) \
169 V(SCRIPT_FUNCTION_INDEX, JSFunction, script_function) \
170 V(OPAQUE_REFERENCE_FUNCTION_INDEX, JSFunction, opaque_reference_function) \
171 V(CONTEXT_EXTENSION_FUNCTION_INDEX, JSFunction, context_extension_function) \
172 V(OUT_OF_MEMORY_INDEX, Object, out_of_memory) \
173 V(MAP_CACHE_INDEX, Object, map_cache) \
174 V(EMBEDDER_DATA_INDEX, FixedArray, embedder_data) \
175 V(ALLOW_CODE_GEN_FROM_STRINGS_INDEX, Object, allow_code_gen_from_strings) \
176 V(ERROR_MESSAGE_FOR_CODE_GEN_FROM_STRINGS_INDEX, Object, \
177 error_message_for_code_gen_from_strings) \
178 V(RUN_MICROTASKS_INDEX, JSFunction, run_microtasks) \
179 V(TO_COMPLETE_PROPERTY_DESCRIPTOR_INDEX, JSFunction, \
180 to_complete_property_descriptor) \
181 V(DERIVED_HAS_TRAP_INDEX, JSFunction, derived_has_trap) \
182 V(DERIVED_GET_TRAP_INDEX, JSFunction, derived_get_trap) \
183 V(DERIVED_SET_TRAP_INDEX, JSFunction, derived_set_trap) \
184 V(PROXY_ENUMERATE_INDEX, JSFunction, proxy_enumerate) \
185 V(OBSERVERS_NOTIFY_CHANGE_INDEX, JSFunction, observers_notify_change) \
186 V(OBSERVERS_ENQUEUE_SPLICE_INDEX, JSFunction, observers_enqueue_splice) \
187 V(OBSERVERS_BEGIN_SPLICE_INDEX, JSFunction, \
188 observers_begin_perform_splice) \
189 V(OBSERVERS_END_SPLICE_INDEX, JSFunction, \
190 observers_end_perform_splice) \
191 V(GENERATOR_FUNCTION_MAP_INDEX, Map, generator_function_map) \
192 V(STRICT_MODE_GENERATOR_FUNCTION_MAP_INDEX, Map, \
193 strict_mode_generator_function_map) \
194 V(GENERATOR_OBJECT_PROTOTYPE_MAP_INDEX, Map, \
195 generator_object_prototype_map) \
196 V(GENERATOR_RESULT_MAP_INDEX, Map, generator_result_map)
198 // JSFunctions are pairs (context, function code), sometimes also called
199 // closures. A Context object is used to represent function contexts and
200 // dynamically pushed 'with' contexts (or 'scopes' in ECMA-262 speak).
202 // At runtime, the contexts build a stack in parallel to the execution
203 // stack, with the top-most context being the current context. All contexts
204 // have the following slots:
206 // [ closure ] This is the current function. It is the same for all
207 // contexts inside a function. It provides access to the
208 // incoming context (i.e., the outer context, which may
209 // or may not become the current function's context), and
210 // it provides access to the functions code and thus it's
211 // scope information, which in turn contains the names of
212 // statically allocated context slots. The names are needed
213 // for dynamic lookups in the presence of 'with' or 'eval'.
215 // [ previous ] A pointer to the previous context. It is NULL for
216 // function contexts, and non-NULL for 'with' contexts.
217 // Used to implement the 'with' statement.
219 // [ extension ] A pointer to an extension JSObject, or NULL. Used to
220 // implement 'with' statements and dynamic declarations
221 // (through 'eval'). The object in a 'with' statement is
222 // stored in the extension slot of a 'with' context.
223 // Dynamically declared variables/functions are also added
224 // to lazily allocated extension object. Context::Lookup
225 // searches the extension object for properties.
226 // For global and block contexts, contains the respective
228 // For module contexts, points back to the respective JSModule.
230 // [ global_object ] A pointer to the global object. Provided for quick
231 // access to the global object from inside the code (since
232 // we always have a context pointer).
234 // In addition, function contexts may have statically allocated context slots
235 // to store local variables/functions that are accessed from inner functions
236 // (via static context addresses) or through 'eval' (dynamic context lookups).
237 // Finally, the native context contains additional slots for fast access to
238 // native properties.
240 class Context: public FixedArray {
243 static Context* cast(Object* context) {
244 ASSERT(context->IsContext());
245 return reinterpret_cast<Context*>(context);
248 // The default context slot layout; indices are FixedArray slot indices.
250 // These slots are in all contexts.
253 // The extension slot is used for either the global object (in global
254 // contexts), eval extension object (function contexts), subject of with
255 // (with contexts), or the variable name (catch contexts), the serialized
256 // scope info (block contexts), or the module instance (module contexts).
261 // This slot holds the thrown value in catch contexts.
262 THROWN_OBJECT_INDEX = MIN_CONTEXT_SLOTS,
264 // These slots are only in native contexts.
265 GLOBAL_PROXY_INDEX = MIN_CONTEXT_SLOTS,
266 SECURITY_TOKEN_INDEX,
267 ARGUMENTS_BOILERPLATE_INDEX,
268 ALIASED_ARGUMENTS_BOILERPLATE_INDEX,
269 STRICT_MODE_ARGUMENTS_BOILERPLATE_INDEX,
270 REGEXP_RESULT_MAP_INDEX,
272 STRICT_MODE_FUNCTION_MAP_INDEX,
273 FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX,
274 STRICT_MODE_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX,
275 INITIAL_OBJECT_PROTOTYPE_INDEX,
276 INITIAL_ARRAY_PROTOTYPE_INDEX,
277 BOOLEAN_FUNCTION_INDEX,
278 NUMBER_FUNCTION_INDEX,
279 FLOAT32x4_FUNCTION_INDEX,
280 FLOAT32x4_FUNCTION_PROTOTYPE_MAP_INDEX,
281 INT32x4_FUNCTION_INDEX,
282 INT32x4_FUNCTION_PROTOTYPE_MAP_INDEX,
283 STRING_FUNCTION_INDEX,
284 STRING_FUNCTION_PROTOTYPE_MAP_INDEX,
285 SYMBOL_FUNCTION_INDEX,
286 OBJECT_FUNCTION_INDEX,
287 INTERNAL_ARRAY_FUNCTION_INDEX,
288 ARRAY_FUNCTION_INDEX,
293 REGEXP_FUNCTION_INDEX,
294 CREATE_DATE_FUN_INDEX,
297 TO_DETAIL_STRING_FUN_INDEX,
299 TO_INTEGER_FUN_INDEX,
302 TO_BOOLEAN_FUN_INDEX,
303 GLOBAL_EVAL_FUN_INDEX,
304 INSTANTIATE_FUN_INDEX,
305 CONFIGURE_INSTANCE_FUN_INDEX,
306 ARRAY_BUFFER_FUN_INDEX,
307 UINT8_ARRAY_FUN_INDEX,
308 INT8_ARRAY_FUN_INDEX,
309 UINT16_ARRAY_FUN_INDEX,
310 INT16_ARRAY_FUN_INDEX,
311 UINT32_ARRAY_FUN_INDEX,
312 INT32_ARRAY_FUN_INDEX,
313 FLOAT32_ARRAY_FUN_INDEX,
314 FLOAT32x4_ARRAY_FUN_INDEX,
315 INT32x4_ARRAY_FUN_INDEX,
316 FLOAT64_ARRAY_FUN_INDEX,
317 UINT8_CLAMPED_ARRAY_FUN_INDEX,
319 MESSAGE_LISTENERS_INDEX,
320 MAKE_MESSAGE_FUN_INDEX,
321 GET_STACK_TRACE_LINE_INDEX,
322 CONFIGURE_GLOBAL_INDEX,
323 FUNCTION_CACHE_INDEX,
324 JSFUNCTION_RESULT_CACHES_INDEX,
325 NORMALIZED_MAP_CACHE_INDEX,
326 RUNTIME_CONTEXT_INDEX,
327 CALL_AS_FUNCTION_DELEGATE_INDEX,
328 CALL_AS_CONSTRUCTOR_DELEGATE_INDEX,
329 SCRIPT_FUNCTION_INDEX,
330 OPAQUE_REFERENCE_FUNCTION_INDEX,
331 CONTEXT_EXTENSION_FUNCTION_INDEX,
334 ALLOW_CODE_GEN_FROM_STRINGS_INDEX,
335 ERROR_MESSAGE_FOR_CODE_GEN_FROM_STRINGS_INDEX,
336 RUN_MICROTASKS_INDEX,
337 TO_COMPLETE_PROPERTY_DESCRIPTOR_INDEX,
338 DERIVED_HAS_TRAP_INDEX,
339 DERIVED_GET_TRAP_INDEX,
340 DERIVED_SET_TRAP_INDEX,
341 PROXY_ENUMERATE_INDEX,
342 OBSERVERS_NOTIFY_CHANGE_INDEX,
343 OBSERVERS_ENQUEUE_SPLICE_INDEX,
344 OBSERVERS_BEGIN_SPLICE_INDEX,
345 OBSERVERS_END_SPLICE_INDEX,
346 GENERATOR_FUNCTION_MAP_INDEX,
347 STRICT_MODE_GENERATOR_FUNCTION_MAP_INDEX,
348 GENERATOR_OBJECT_PROTOTYPE_MAP_INDEX,
349 GENERATOR_RESULT_MAP_INDEX,
351 // Properties from here are treated as weak references by the full GC.
352 // Scavenge treats them as strong references.
353 OPTIMIZED_FUNCTIONS_LIST, // Weak.
354 OPTIMIZED_CODE_LIST, // Weak.
355 DEOPTIMIZED_CODE_LIST, // Weak.
356 MAP_CACHE_INDEX, // Weak.
357 NEXT_CONTEXT_LINK, // Weak.
359 // Total number of slots.
360 NATIVE_CONTEXT_SLOTS,
362 FIRST_WEAK_SLOT = OPTIMIZED_FUNCTIONS_LIST
365 // Direct slot access.
366 JSFunction* closure() { return JSFunction::cast(get(CLOSURE_INDEX)); }
367 void set_closure(JSFunction* closure) { set(CLOSURE_INDEX, closure); }
369 Context* previous() {
370 Object* result = unchecked_previous();
371 ASSERT(IsBootstrappingOrValidParentContext(result, this));
372 return reinterpret_cast<Context*>(result);
374 void set_previous(Context* context) { set(PREVIOUS_INDEX, context); }
376 bool has_extension() { return extension() != NULL; }
377 Object* extension() { return get(EXTENSION_INDEX); }
378 void set_extension(Object* object) { set(EXTENSION_INDEX, object); }
380 JSModule* module() { return JSModule::cast(get(EXTENSION_INDEX)); }
381 void set_module(JSModule* module) { set(EXTENSION_INDEX, module); }
383 // Get the context where var declarations will be hoisted to, which
384 // may be the context itself.
385 Context* declaration_context();
387 GlobalObject* global_object() {
388 Object* result = get(GLOBAL_OBJECT_INDEX);
389 ASSERT(IsBootstrappingOrGlobalObject(this->GetIsolate(), result));
390 return reinterpret_cast<GlobalObject*>(result);
392 void set_global_object(GlobalObject* object) {
393 set(GLOBAL_OBJECT_INDEX, object);
396 // Returns a JSGlobalProxy object or null.
397 JSObject* global_proxy();
398 void set_global_proxy(JSObject* global);
400 // The builtins object.
401 JSBuiltinsObject* builtins();
403 // Get the innermost global context by traversing the context chain.
404 Context* global_context();
406 // Compute the native context by traversing the context chain.
407 Context* native_context();
409 // Predicates for context types. IsNativeContext is also defined on Object
410 // because we frequently have to know if arbitrary objects are natives
412 bool IsNativeContext() {
413 Map* map = this->map();
414 return map == map->GetHeap()->native_context_map();
416 bool IsFunctionContext() {
417 Map* map = this->map();
418 return map == map->GetHeap()->function_context_map();
420 bool IsCatchContext() {
421 Map* map = this->map();
422 return map == map->GetHeap()->catch_context_map();
424 bool IsWithContext() {
425 Map* map = this->map();
426 return map == map->GetHeap()->with_context_map();
428 bool IsBlockContext() {
429 Map* map = this->map();
430 return map == map->GetHeap()->block_context_map();
432 bool IsModuleContext() {
433 Map* map = this->map();
434 return map == map->GetHeap()->module_context_map();
436 bool IsGlobalContext() {
437 Map* map = this->map();
438 return map == map->GetHeap()->global_context_map();
441 // Tells whether the native context is marked with out of memory.
442 inline bool has_out_of_memory();
444 // Mark the native context with out of memory.
445 inline void mark_out_of_memory();
447 // A native context holds a list of all functions with optimized code.
448 void AddOptimizedFunction(JSFunction* function);
449 void RemoveOptimizedFunction(JSFunction* function);
450 void SetOptimizedFunctionsListHead(Object* head);
451 Object* OptimizedFunctionsListHead();
453 // The native context also stores a list of all optimized code and a
454 // list of all deoptimized code, which are needed by the deoptimizer.
455 void AddOptimizedCode(Code* code);
456 void SetOptimizedCodeListHead(Object* head);
457 Object* OptimizedCodeListHead();
458 void SetDeoptimizedCodeListHead(Object* head);
459 Object* DeoptimizedCodeListHead();
461 Handle<Object> ErrorMessageForCodeGenerationFromStrings();
463 #define NATIVE_CONTEXT_FIELD_ACCESSORS(index, type, name) \
464 void set_##name(type* value) { \
465 ASSERT(IsNativeContext()); \
468 bool is_##name(type* value) { \
469 ASSERT(IsNativeContext()); \
470 return type::cast(get(index)) == value; \
473 ASSERT(IsNativeContext()); \
474 return type::cast(get(index)); \
476 NATIVE_CONTEXT_FIELDS(NATIVE_CONTEXT_FIELD_ACCESSORS)
477 #undef NATIVE_CONTEXT_FIELD_ACCESSORS
479 // Lookup the slot called name, starting with the current context.
480 // There are three possibilities:
482 // 1) result->IsContext():
483 // The binding was found in a context. *index is always the
484 // non-negative slot index. *attributes is NONE for var and let
485 // declarations, READ_ONLY for const declarations (never ABSENT).
487 // 2) result->IsJSObject():
488 // The binding was found as a named property in a context extension
489 // object (i.e., was introduced via eval), as a property on the subject
490 // of with, or as a property of the global object. *index is -1 and
491 // *attributes is not ABSENT.
493 // 3) result.is_null():
494 // There was no binding found, *index is always -1 and *attributes is
496 Handle<Object> Lookup(Handle<String> name,
497 ContextLookupFlags flags,
499 PropertyAttributes* attributes,
500 BindingFlags* binding_flags);
502 // Code generation support.
503 static int SlotOffset(int index) {
504 return kHeaderSize + index * kPointerSize - kHeapObjectTag;
507 static int FunctionMapIndex(LanguageMode language_mode, bool is_generator) {
509 ? (language_mode == CLASSIC_MODE
510 ? GENERATOR_FUNCTION_MAP_INDEX
511 : STRICT_MODE_GENERATOR_FUNCTION_MAP_INDEX)
512 : (language_mode == CLASSIC_MODE
514 : STRICT_MODE_FUNCTION_MAP_INDEX);
517 static const int kSize = kHeaderSize + NATIVE_CONTEXT_SLOTS * kPointerSize;
520 typedef FixedBodyDescriptor<
521 kHeaderSize, kSize, kSize> ScavengeBodyDescriptor;
523 typedef FixedBodyDescriptor<
525 kHeaderSize + FIRST_WEAK_SLOT * kPointerSize,
526 kSize> MarkCompactBodyDescriptor;
529 // Unchecked access to the slots.
530 Object* unchecked_previous() { return get(PREVIOUS_INDEX); }
533 // Bootstrapping-aware type checks.
534 static bool IsBootstrappingOrValidParentContext(Object* object, Context* kid);
535 static bool IsBootstrappingOrGlobalObject(Isolate* isolate, Object* object);
538 STATIC_CHECK(kHeaderSize == Internals::kContextHeaderSize);
539 STATIC_CHECK(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex);
542 } } // namespace v8::internal
544 #endif // V8_CONTEXTS_H_