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