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. 4 5 #ifndef V8_CONTEXTS_H_ 6 #define V8_CONTEXTS_H_ 7 8 #include "src/heap/heap.h" 9 #include "src/objects.h" 10 11 namespace v8 { 12 namespace internal { 13 14 15 enum ContextLookupFlags { 16 FOLLOW_CONTEXT_CHAIN = 1, 17 FOLLOW_PROTOTYPE_CHAIN = 2, 18 19 DONT_FOLLOW_CHAINS = 0, 20 FOLLOW_CHAINS = FOLLOW_CONTEXT_CHAIN | FOLLOW_PROTOTYPE_CHAIN 21 }; 22 23 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. 30 // 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. 39 // 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. 53 // 54 // In V8 uninitialized bindings are set to the hole value upon creation and set 55 // to a different value upon initialization. 56 enum BindingFlags { 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, 63 MISSING_BINDING 64 }; 65 66 67 // Heap-allocated activation contexts. 68 // 69 // Contexts are implemented as FixedArray objects; the Context 70 // class is a convenience interface casted on a FixedArray object. 71 // 72 // Note: Context must have no virtual functions and Context objects 73 // must always be allocated via Heap::AllocateContext() or 74 // Factory::NewContext. 75 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(GLOBAL_EVAL_FUN_INDEX, JSFunction, global_eval_fun) \ 102 V(INSTANTIATE_FUN_INDEX, JSFunction, instantiate_fun) \ 103 V(CONFIGURE_INSTANCE_FUN_INDEX, JSFunction, configure_instance_fun) \ 104 V(MATH_ABS_FUN_INDEX, JSFunction, math_abs_fun) \ 105 V(MATH_ACOS_FUN_INDEX, JSFunction, math_acos_fun) \ 106 V(MATH_ASIN_FUN_INDEX, JSFunction, math_asin_fun) \ 107 V(MATH_ATAN_FUN_INDEX, JSFunction, math_atan_fun) \ 108 V(MATH_ATAN2_FUN_INDEX, JSFunction, math_atan2_fun) \ 109 V(MATH_CEIL_FUN_INDEX, JSFunction, math_ceil_fun) \ 110 V(MATH_COS_FUN_INDEX, JSFunction, math_cos_fun) \ 111 V(MATH_EXP_FUN_INDEX, JSFunction, math_exp_fun) \ 112 V(MATH_FLOOR_FUN_INDEX, JSFunction, math_floor_fun) \ 113 V(MATH_IMUL_FUN_INDEX, JSFunction, math_imul_fun) \ 114 V(MATH_LOG_FUN_INDEX, JSFunction, math_log_fun) \ 115 V(MATH_MAX_FUN_INDEX, JSFunction, math_max_fun) \ 116 V(MATH_MIN_FUN_INDEX, JSFunction, math_min_fun) \ 117 V(MATH_POW_FUN_INDEX, JSFunction, math_pow_fun) \ 118 V(MATH_RANDOM_FUN_INDEX, JSFunction, math_random_fun) \ 119 V(MATH_ROUND_FUN_INDEX, JSFunction, math_round_fun) \ 120 V(MATH_SIN_FUN_INDEX, JSFunction, math_sin_fun) \ 121 V(MATH_SQRT_FUN_INDEX, JSFunction, math_sqrt_fun) \ 122 V(MATH_TAN_FUN_INDEX, JSFunction, math_tan_fun) \ 123 V(ARRAY_BUFFER_FUN_INDEX, JSFunction, array_buffer_fun) \ 124 V(UINT8_ARRAY_FUN_INDEX, JSFunction, uint8_array_fun) \ 125 V(INT8_ARRAY_FUN_INDEX, JSFunction, int8_array_fun) \ 126 V(UINT16_ARRAY_FUN_INDEX, JSFunction, uint16_array_fun) \ 127 V(INT16_ARRAY_FUN_INDEX, JSFunction, int16_array_fun) \ 128 V(UINT32_ARRAY_FUN_INDEX, JSFunction, uint32_array_fun) \ 129 V(INT32_ARRAY_FUN_INDEX, JSFunction, int32_array_fun) \ 130 V(FLOAT32_ARRAY_FUN_INDEX, JSFunction, float32_array_fun) \ 131 V(FLOAT64_ARRAY_FUN_INDEX, JSFunction, float64_array_fun) \ 132 V(UINT8_CLAMPED_ARRAY_FUN_INDEX, JSFunction, uint8_clamped_array_fun) \ 133 V(INT8_ARRAY_EXTERNAL_MAP_INDEX, Map, int8_array_external_map) \ 134 V(UINT8_ARRAY_EXTERNAL_MAP_INDEX, Map, uint8_array_external_map) \ 135 V(INT16_ARRAY_EXTERNAL_MAP_INDEX, Map, int16_array_external_map) \ 136 V(UINT16_ARRAY_EXTERNAL_MAP_INDEX, Map, uint16_array_external_map) \ 137 V(INT32_ARRAY_EXTERNAL_MAP_INDEX, Map, int32_array_external_map) \ 138 V(UINT32_ARRAY_EXTERNAL_MAP_INDEX, Map, uint32_array_external_map) \ 139 V(FLOAT32_ARRAY_EXTERNAL_MAP_INDEX, Map, float32_array_external_map) \ 140 V(FLOAT64_ARRAY_EXTERNAL_MAP_INDEX, Map, float64_array_external_map) \ 141 V(UINT8_CLAMPED_ARRAY_EXTERNAL_MAP_INDEX, Map, \ 142 uint8_clamped_array_external_map) \ 143 V(DATA_VIEW_FUN_INDEX, JSFunction, data_view_fun) \ 144 V(SLOPPY_FUNCTION_MAP_INDEX, Map, sloppy_function_map) \ 145 V(SLOPPY_FUNCTION_WITH_READONLY_PROTOTYPE_MAP_INDEX, Map, \ 146 sloppy_function_with_readonly_prototype_map) \ 147 V(STRICT_FUNCTION_MAP_INDEX, Map, strict_function_map) \ 148 V(SLOPPY_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, Map, \ 149 sloppy_function_without_prototype_map) \ 150 V(STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, Map, \ 151 strict_function_without_prototype_map) \ 152 V(BOUND_FUNCTION_MAP_INDEX, Map, bound_function_map) \ 153 V(REGEXP_RESULT_MAP_INDEX, Map, regexp_result_map) \ 154 V(SLOPPY_ARGUMENTS_MAP_INDEX, Map, sloppy_arguments_map) \ 155 V(ALIASED_ARGUMENTS_MAP_INDEX, Map, aliased_arguments_map) \ 156 V(STRICT_ARGUMENTS_MAP_INDEX, Map, strict_arguments_map) \ 157 V(MESSAGE_LISTENERS_INDEX, JSObject, message_listeners) \ 158 V(MAKE_MESSAGE_FUN_INDEX, JSFunction, make_message_fun) \ 159 V(GET_STACK_TRACE_LINE_INDEX, JSFunction, get_stack_trace_line_fun) \ 160 V(CONFIGURE_GLOBAL_INDEX, JSFunction, configure_global_fun) \ 161 V(FUNCTION_CACHE_INDEX, JSObject, function_cache) \ 162 V(JSFUNCTION_RESULT_CACHES_INDEX, FixedArray, jsfunction_result_caches) \ 163 V(NORMALIZED_MAP_CACHE_INDEX, Object, normalized_map_cache) \ 164 V(RUNTIME_CONTEXT_INDEX, Context, runtime_context) \ 165 V(CALL_AS_FUNCTION_DELEGATE_INDEX, JSFunction, call_as_function_delegate) \ 166 V(CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, JSFunction, \ 167 call_as_constructor_delegate) \ 168 V(SCRIPT_FUNCTION_INDEX, JSFunction, script_function) \ 169 V(OPAQUE_REFERENCE_FUNCTION_INDEX, JSFunction, opaque_reference_function) \ 170 V(CONTEXT_EXTENSION_FUNCTION_INDEX, JSFunction, context_extension_function) \ 171 V(MAP_CACHE_INDEX, Object, map_cache) \ 172 V(EMBEDDER_DATA_INDEX, FixedArray, embedder_data) \ 173 V(ALLOW_CODE_GEN_FROM_STRINGS_INDEX, Object, allow_code_gen_from_strings) \ 174 V(ERROR_MESSAGE_FOR_CODE_GEN_FROM_STRINGS_INDEX, Object, \ 175 error_message_for_code_gen_from_strings) \ 176 V(IS_PROMISE_INDEX, JSFunction, is_promise) \ 177 V(PROMISE_CREATE_INDEX, JSFunction, promise_create) \ 178 V(PROMISE_RESOLVE_INDEX, JSFunction, promise_resolve) \ 179 V(PROMISE_REJECT_INDEX, JSFunction, promise_reject) \ 180 V(PROMISE_CHAIN_INDEX, JSFunction, promise_chain) \ 181 V(PROMISE_CATCH_INDEX, JSFunction, promise_catch) \ 182 V(PROMISE_THEN_INDEX, JSFunction, promise_then) \ 183 V(TO_COMPLETE_PROPERTY_DESCRIPTOR_INDEX, JSFunction, \ 184 to_complete_property_descriptor) \ 185 V(DERIVED_HAS_TRAP_INDEX, JSFunction, derived_has_trap) \ 186 V(DERIVED_GET_TRAP_INDEX, JSFunction, derived_get_trap) \ 187 V(DERIVED_SET_TRAP_INDEX, JSFunction, derived_set_trap) \ 188 V(PROXY_ENUMERATE_INDEX, JSFunction, proxy_enumerate) \ 189 V(OBSERVERS_NOTIFY_CHANGE_INDEX, JSFunction, observers_notify_change) \ 190 V(OBSERVERS_ENQUEUE_SPLICE_INDEX, JSFunction, observers_enqueue_splice) \ 191 V(OBSERVERS_BEGIN_SPLICE_INDEX, JSFunction, observers_begin_perform_splice) \ 192 V(OBSERVERS_END_SPLICE_INDEX, JSFunction, observers_end_perform_splice) \ 193 V(NATIVE_OBJECT_OBSERVE_INDEX, JSFunction, native_object_observe) \ 194 V(NATIVE_OBJECT_GET_NOTIFIER_INDEX, JSFunction, native_object_get_notifier) \ 195 V(NATIVE_OBJECT_NOTIFIER_PERFORM_CHANGE, JSFunction, \ 196 native_object_notifier_perform_change) \ 197 V(SLOPPY_GENERATOR_FUNCTION_MAP_INDEX, Map, sloppy_generator_function_map) \ 198 V(STRICT_GENERATOR_FUNCTION_MAP_INDEX, Map, strict_generator_function_map) \ 199 V(GENERATOR_OBJECT_PROTOTYPE_MAP_INDEX, Map, generator_object_prototype_map) \ 200 V(ITERATOR_RESULT_MAP_INDEX, Map, iterator_result_map) \ 201 V(MAP_ITERATOR_MAP_INDEX, Map, map_iterator_map) \ 202 V(SET_ITERATOR_MAP_INDEX, Map, set_iterator_map) \ 203 V(ITERATOR_SYMBOL_INDEX, Symbol, iterator_symbol) \ 204 V(UNSCOPABLES_SYMBOL_INDEX, Symbol, unscopables_symbol) \ 205 V(ARRAY_VALUES_ITERATOR_INDEX, JSFunction, array_values_iterator) 206 207 // JSFunctions are pairs (context, function code), sometimes also called 208 // closures. A Context object is used to represent function contexts and 209 // dynamically pushed 'with' contexts (or 'scopes' in ECMA-262 speak). 210 // 211 // At runtime, the contexts build a stack in parallel to the execution 212 // stack, with the top-most context being the current context. All contexts 213 // have the following slots: 214 // 215 // [ closure ] This is the current function. It is the same for all 216 // contexts inside a function. It provides access to the 217 // incoming context (i.e., the outer context, which may 218 // or may not become the current function's context), and 219 // it provides access to the functions code and thus it's 220 // scope information, which in turn contains the names of 221 // statically allocated context slots. The names are needed 222 // for dynamic lookups in the presence of 'with' or 'eval'. 223 // 224 // [ previous ] A pointer to the previous context. It is NULL for 225 // function contexts, and non-NULL for 'with' contexts. 226 // Used to implement the 'with' statement. 227 // 228 // [ extension ] A pointer to an extension JSObject, or NULL. Used to 229 // implement 'with' statements and dynamic declarations 230 // (through 'eval'). The object in a 'with' statement is 231 // stored in the extension slot of a 'with' context. 232 // Dynamically declared variables/functions are also added 233 // to lazily allocated extension object. Context::Lookup 234 // searches the extension object for properties. 235 // For global and block contexts, contains the respective 236 // ScopeInfo. 237 // For module contexts, points back to the respective JSModule. 238 // 239 // [ global_object ] A pointer to the global object. Provided for quick 240 // access to the global object from inside the code (since 241 // we always have a context pointer). 242 // 243 // In addition, function contexts may have statically allocated context slots 244 // to store local variables/functions that are accessed from inner functions 245 // (via static context addresses) or through 'eval' (dynamic context lookups). 246 // The native context contains additional slots for fast access to native 247 // properties. 248 // 249 // Finally, with Harmony scoping, the JSFunction representing a top level 250 // script will have the GlobalContext rather than a FunctionContext. 251 252 class Context: public FixedArray { 253 public: 254 // Conversions. 255 static Context* cast(Object* context) { 256 DCHECK(context->IsContext()); 257 return reinterpret_cast<Context*>(context); 258 } 259 260 // The default context slot layout; indices are FixedArray slot indices. 261 enum { 262 // These slots are in all contexts. 263 CLOSURE_INDEX, 264 PREVIOUS_INDEX, 265 // The extension slot is used for either the global object (in global 266 // contexts), eval extension object (function contexts), subject of with 267 // (with contexts), or the variable name (catch contexts), the serialized 268 // scope info (block contexts), or the module instance (module contexts). 269 EXTENSION_INDEX, 270 GLOBAL_OBJECT_INDEX, 271 MIN_CONTEXT_SLOTS, 272 273 // This slot holds the thrown value in catch contexts. 274 THROWN_OBJECT_INDEX = MIN_CONTEXT_SLOTS, 275 276 // These slots are only in native contexts. 277 GLOBAL_PROXY_INDEX = MIN_CONTEXT_SLOTS, 278 SECURITY_TOKEN_INDEX, 279 SLOPPY_ARGUMENTS_MAP_INDEX, 280 ALIASED_ARGUMENTS_MAP_INDEX, 281 STRICT_ARGUMENTS_MAP_INDEX, 282 REGEXP_RESULT_MAP_INDEX, 283 SLOPPY_FUNCTION_MAP_INDEX, 284 SLOPPY_FUNCTION_WITH_READONLY_PROTOTYPE_MAP_INDEX, 285 STRICT_FUNCTION_MAP_INDEX, 286 SLOPPY_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, 287 STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, 288 BOUND_FUNCTION_MAP_INDEX, 289 INITIAL_OBJECT_PROTOTYPE_INDEX, 290 INITIAL_ARRAY_PROTOTYPE_INDEX, 291 BOOLEAN_FUNCTION_INDEX, 292 NUMBER_FUNCTION_INDEX, 293 STRING_FUNCTION_INDEX, 294 STRING_FUNCTION_PROTOTYPE_MAP_INDEX, 295 SYMBOL_FUNCTION_INDEX, 296 OBJECT_FUNCTION_INDEX, 297 INTERNAL_ARRAY_FUNCTION_INDEX, 298 ARRAY_FUNCTION_INDEX, 299 JS_ARRAY_MAPS_INDEX, 300 DATE_FUNCTION_INDEX, 301 JSON_OBJECT_INDEX, 302 REGEXP_FUNCTION_INDEX, 303 CREATE_DATE_FUN_INDEX, 304 TO_NUMBER_FUN_INDEX, 305 TO_STRING_FUN_INDEX, 306 TO_DETAIL_STRING_FUN_INDEX, 307 TO_OBJECT_FUN_INDEX, 308 TO_INTEGER_FUN_INDEX, 309 TO_UINT32_FUN_INDEX, 310 TO_INT32_FUN_INDEX, 311 TO_BOOLEAN_FUN_INDEX, 312 GLOBAL_EVAL_FUN_INDEX, 313 INSTANTIATE_FUN_INDEX, 314 CONFIGURE_INSTANCE_FUN_INDEX, 315 MATH_ABS_FUN_INDEX, 316 MATH_ACOS_FUN_INDEX, 317 MATH_ASIN_FUN_INDEX, 318 MATH_ATAN_FUN_INDEX, 319 MATH_ATAN2_FUN_INDEX, 320 MATH_CEIL_FUN_INDEX, 321 MATH_COS_FUN_INDEX, 322 MATH_EXP_FUN_INDEX, 323 MATH_FLOOR_FUN_INDEX, 324 MATH_IMUL_FUN_INDEX, 325 MATH_LOG_FUN_INDEX, 326 MATH_MAX_FUN_INDEX, 327 MATH_MIN_FUN_INDEX, 328 MATH_POW_FUN_INDEX, 329 MATH_RANDOM_FUN_INDEX, 330 MATH_ROUND_FUN_INDEX, 331 MATH_SIN_FUN_INDEX, 332 MATH_SQRT_FUN_INDEX, 333 MATH_TAN_FUN_INDEX, 334 ARRAY_BUFFER_FUN_INDEX, 335 UINT8_ARRAY_FUN_INDEX, 336 INT8_ARRAY_FUN_INDEX, 337 UINT16_ARRAY_FUN_INDEX, 338 INT16_ARRAY_FUN_INDEX, 339 UINT32_ARRAY_FUN_INDEX, 340 INT32_ARRAY_FUN_INDEX, 341 FLOAT32_ARRAY_FUN_INDEX, 342 FLOAT64_ARRAY_FUN_INDEX, 343 UINT8_CLAMPED_ARRAY_FUN_INDEX, 344 INT8_ARRAY_EXTERNAL_MAP_INDEX, 345 UINT8_ARRAY_EXTERNAL_MAP_INDEX, 346 INT16_ARRAY_EXTERNAL_MAP_INDEX, 347 UINT16_ARRAY_EXTERNAL_MAP_INDEX, 348 INT32_ARRAY_EXTERNAL_MAP_INDEX, 349 UINT32_ARRAY_EXTERNAL_MAP_INDEX, 350 FLOAT32_ARRAY_EXTERNAL_MAP_INDEX, 351 FLOAT64_ARRAY_EXTERNAL_MAP_INDEX, 352 UINT8_CLAMPED_ARRAY_EXTERNAL_MAP_INDEX, 353 DATA_VIEW_FUN_INDEX, 354 MESSAGE_LISTENERS_INDEX, 355 MAKE_MESSAGE_FUN_INDEX, 356 GET_STACK_TRACE_LINE_INDEX, 357 CONFIGURE_GLOBAL_INDEX, 358 FUNCTION_CACHE_INDEX, 359 JSFUNCTION_RESULT_CACHES_INDEX, 360 NORMALIZED_MAP_CACHE_INDEX, 361 RUNTIME_CONTEXT_INDEX, 362 CALL_AS_FUNCTION_DELEGATE_INDEX, 363 CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, 364 SCRIPT_FUNCTION_INDEX, 365 OPAQUE_REFERENCE_FUNCTION_INDEX, 366 CONTEXT_EXTENSION_FUNCTION_INDEX, 367 OUT_OF_MEMORY_INDEX, 368 EMBEDDER_DATA_INDEX, 369 ALLOW_CODE_GEN_FROM_STRINGS_INDEX, 370 ERROR_MESSAGE_FOR_CODE_GEN_FROM_STRINGS_INDEX, 371 RUN_MICROTASKS_INDEX, 372 ENQUEUE_MICROTASK_INDEX, 373 IS_PROMISE_INDEX, 374 PROMISE_CREATE_INDEX, 375 PROMISE_RESOLVE_INDEX, 376 PROMISE_REJECT_INDEX, 377 PROMISE_CHAIN_INDEX, 378 PROMISE_CATCH_INDEX, 379 PROMISE_THEN_INDEX, 380 TO_COMPLETE_PROPERTY_DESCRIPTOR_INDEX, 381 DERIVED_HAS_TRAP_INDEX, 382 DERIVED_GET_TRAP_INDEX, 383 DERIVED_SET_TRAP_INDEX, 384 PROXY_ENUMERATE_INDEX, 385 OBSERVERS_NOTIFY_CHANGE_INDEX, 386 OBSERVERS_ENQUEUE_SPLICE_INDEX, 387 OBSERVERS_BEGIN_SPLICE_INDEX, 388 OBSERVERS_END_SPLICE_INDEX, 389 NATIVE_OBJECT_OBSERVE_INDEX, 390 NATIVE_OBJECT_GET_NOTIFIER_INDEX, 391 NATIVE_OBJECT_NOTIFIER_PERFORM_CHANGE, 392 SLOPPY_GENERATOR_FUNCTION_MAP_INDEX, 393 STRICT_GENERATOR_FUNCTION_MAP_INDEX, 394 GENERATOR_OBJECT_PROTOTYPE_MAP_INDEX, 395 ITERATOR_RESULT_MAP_INDEX, 396 MAP_ITERATOR_MAP_INDEX, 397 SET_ITERATOR_MAP_INDEX, 398 ITERATOR_SYMBOL_INDEX, 399 UNSCOPABLES_SYMBOL_INDEX, 400 ARRAY_VALUES_ITERATOR_INDEX, 401 402 // Properties from here are treated as weak references by the full GC. 403 // Scavenge treats them as strong references. 404 OPTIMIZED_FUNCTIONS_LIST, // Weak. 405 OPTIMIZED_CODE_LIST, // Weak. 406 DEOPTIMIZED_CODE_LIST, // Weak. 407 MAP_CACHE_INDEX, // Weak. 408 NEXT_CONTEXT_LINK, // Weak. 409 410 // Total number of slots. 411 NATIVE_CONTEXT_SLOTS, 412 FIRST_WEAK_SLOT = OPTIMIZED_FUNCTIONS_LIST 413 }; 414 415 // Direct slot access. 416 JSFunction* closure() { return JSFunction::cast(get(CLOSURE_INDEX)); } 417 void set_closure(JSFunction* closure) { set(CLOSURE_INDEX, closure); } 418 419 Context* previous() { 420 Object* result = unchecked_previous(); 421 DCHECK(IsBootstrappingOrValidParentContext(result, this)); 422 return reinterpret_cast<Context*>(result); 423 } 424 void set_previous(Context* context) { set(PREVIOUS_INDEX, context); } 425 426 bool has_extension() { return extension() != NULL; } 427 Object* extension() { return get(EXTENSION_INDEX); } 428 void set_extension(Object* object) { set(EXTENSION_INDEX, object); } 429 430 JSModule* module() { return JSModule::cast(get(EXTENSION_INDEX)); } 431 void set_module(JSModule* module) { set(EXTENSION_INDEX, module); } 432 433 // Get the context where var declarations will be hoisted to, which 434 // may be the context itself. 435 Context* declaration_context(); 436 437 GlobalObject* global_object() { 438 Object* result = get(GLOBAL_OBJECT_INDEX); 439 DCHECK(IsBootstrappingOrGlobalObject(this->GetIsolate(), result)); 440 return reinterpret_cast<GlobalObject*>(result); 441 } 442 void set_global_object(GlobalObject* object) { 443 set(GLOBAL_OBJECT_INDEX, object); 444 } 445 446 // Returns a JSGlobalProxy object or null. 447 JSObject* global_proxy(); 448 void set_global_proxy(JSObject* global); 449 450 // The builtins object. 451 JSBuiltinsObject* builtins(); 452 453 // Get the innermost global context by traversing the context chain. 454 Context* global_context(); 455 456 // Compute the native context by traversing the context chain. 457 Context* native_context(); 458 459 // Predicates for context types. IsNativeContext is also defined on Object 460 // because we frequently have to know if arbitrary objects are natives 461 // contexts. 462 bool IsNativeContext() { 463 Map* map = this->map(); 464 return map == map->GetHeap()->native_context_map(); 465 } 466 bool IsFunctionContext() { 467 Map* map = this->map(); 468 return map == map->GetHeap()->function_context_map(); 469 } 470 bool IsCatchContext() { 471 Map* map = this->map(); 472 return map == map->GetHeap()->catch_context_map(); 473 } 474 bool IsWithContext() { 475 Map* map = this->map(); 476 return map == map->GetHeap()->with_context_map(); 477 } 478 bool IsBlockContext() { 479 Map* map = this->map(); 480 return map == map->GetHeap()->block_context_map(); 481 } 482 bool IsModuleContext() { 483 Map* map = this->map(); 484 return map == map->GetHeap()->module_context_map(); 485 } 486 bool IsGlobalContext() { 487 Map* map = this->map(); 488 return map == map->GetHeap()->global_context_map(); 489 } 490 491 bool HasSameSecurityTokenAs(Context* that) { 492 return this->global_object()->native_context()->security_token() == 493 that->global_object()->native_context()->security_token(); 494 } 495 496 // A native context holds a list of all functions with optimized code. 497 void AddOptimizedFunction(JSFunction* function); 498 void RemoveOptimizedFunction(JSFunction* function); 499 void SetOptimizedFunctionsListHead(Object* head); 500 Object* OptimizedFunctionsListHead(); 501 502 // The native context also stores a list of all optimized code and a 503 // list of all deoptimized code, which are needed by the deoptimizer. 504 void AddOptimizedCode(Code* code); 505 void SetOptimizedCodeListHead(Object* head); 506 Object* OptimizedCodeListHead(); 507 void SetDeoptimizedCodeListHead(Object* head); 508 Object* DeoptimizedCodeListHead(); 509 510 Handle<Object> ErrorMessageForCodeGenerationFromStrings(); 511 512 #define NATIVE_CONTEXT_FIELD_ACCESSORS(index, type, name) \ 513 void set_##name(type* value) { \ 514 DCHECK(IsNativeContext()); \ 515 set(index, value); \ 516 } \ 517 bool is_##name(type* value) { \ 518 DCHECK(IsNativeContext()); \ 519 return type::cast(get(index)) == value; \ 520 } \ 521 type* name() { \ 522 DCHECK(IsNativeContext()); \ 523 return type::cast(get(index)); \ 524 } 525 NATIVE_CONTEXT_FIELDS(NATIVE_CONTEXT_FIELD_ACCESSORS) 526 #undef NATIVE_CONTEXT_FIELD_ACCESSORS 527 528 // Lookup the slot called name, starting with the current context. 529 // There are three possibilities: 530 // 531 // 1) result->IsContext(): 532 // The binding was found in a context. *index is always the 533 // non-negative slot index. *attributes is NONE for var and let 534 // declarations, READ_ONLY for const declarations (never ABSENT). 535 // 536 // 2) result->IsJSObject(): 537 // The binding was found as a named property in a context extension 538 // object (i.e., was introduced via eval), as a property on the subject 539 // of with, or as a property of the global object. *index is -1 and 540 // *attributes is not ABSENT. 541 // 542 // 3) result.is_null(): 543 // There was no binding found, *index is always -1 and *attributes is 544 // always ABSENT. 545 Handle<Object> Lookup(Handle<String> name, 546 ContextLookupFlags flags, 547 int* index, 548 PropertyAttributes* attributes, 549 BindingFlags* binding_flags); 550 551 // Code generation support. 552 static int SlotOffset(int index) { 553 return kHeaderSize + index * kPointerSize - kHeapObjectTag; 554 } 555 556 static int FunctionMapIndex(StrictMode strict_mode, FunctionKind kind) { 557 if (IsGeneratorFunction(kind)) { 558 return strict_mode == SLOPPY ? SLOPPY_GENERATOR_FUNCTION_MAP_INDEX 559 : STRICT_GENERATOR_FUNCTION_MAP_INDEX; 560 } 561 562 if (IsArrowFunction(kind) || IsConciseMethod(kind)) { 563 return strict_mode == SLOPPY 564 ? SLOPPY_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX 565 : STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX; 566 } 567 568 return strict_mode == SLOPPY ? SLOPPY_FUNCTION_MAP_INDEX 569 : STRICT_FUNCTION_MAP_INDEX; 570 } 571 572 static const int kSize = kHeaderSize + NATIVE_CONTEXT_SLOTS * kPointerSize; 573 574 // GC support. 575 typedef FixedBodyDescriptor< 576 kHeaderSize, kSize, kSize> ScavengeBodyDescriptor; 577 578 typedef FixedBodyDescriptor< 579 kHeaderSize, 580 kHeaderSize + FIRST_WEAK_SLOT * kPointerSize, 581 kSize> MarkCompactBodyDescriptor; 582 583 private: 584 // Unchecked access to the slots. 585 Object* unchecked_previous() { return get(PREVIOUS_INDEX); } 586 587 #ifdef DEBUG 588 // Bootstrapping-aware type checks. 589 static bool IsBootstrappingOrValidParentContext(Object* object, Context* kid); 590 static bool IsBootstrappingOrGlobalObject(Isolate* isolate, Object* object); 591 #endif 592 593 STATIC_ASSERT(kHeaderSize == Internals::kContextHeaderSize); 594 STATIC_ASSERT(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex); 595 }; 596 597 } } // namespace v8::internal 598 599 #endif // V8_CONTEXTS_H_ 600
