// Copyright 2012 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef V8_CONTEXTS_H_ #define V8_CONTEXTS_H_ #include "src/heap.h" #include "src/objects.h" namespace v8 { namespace internal { enum ContextLookupFlags { FOLLOW_CONTEXT_CHAIN = 1, FOLLOW_PROTOTYPE_CHAIN = 2, DONT_FOLLOW_CHAINS = 0, FOLLOW_CHAINS = FOLLOW_CONTEXT_CHAIN | FOLLOW_PROTOTYPE_CHAIN }; // ES5 10.2 defines lexical environments with mutable and immutable bindings. // Immutable bindings have two states, initialized and uninitialized, and // their state is changed by the InitializeImmutableBinding method. The // BindingFlags enum represents information if a binding has definitely been // initialized. A mutable binding does not need to be checked and thus has // the BindingFlag MUTABLE_IS_INITIALIZED. // // There are two possibilities for immutable bindings // * 'const' declared variables. They are initialized when evaluating the // corresponding declaration statement. They need to be checked for being // initialized and thus get the flag IMMUTABLE_CHECK_INITIALIZED. // * The function name of a named function literal. The binding is immediately // initialized when entering the function and thus does not need to be // checked. it gets the BindingFlag IMMUTABLE_IS_INITIALIZED. // Accessing an uninitialized binding produces the undefined value. // // The harmony proposal for block scoped bindings also introduces the // uninitialized state for mutable bindings. // * A 'let' declared variable. They are initialized when evaluating the // corresponding declaration statement. They need to be checked for being // initialized and thus get the flag MUTABLE_CHECK_INITIALIZED. // * A 'var' declared variable. It is initialized immediately upon creation // and thus doesn't need to be checked. It gets the flag // MUTABLE_IS_INITIALIZED. // * Catch bound variables, function parameters and variables introduced by // function declarations are initialized immediately and do not need to be // checked. Thus they get the flag MUTABLE_IS_INITIALIZED. // Immutable bindings in harmony mode get the _HARMONY flag variants. Accessing // an uninitialized binding produces a reference error. // // In V8 uninitialized bindings are set to the hole value upon creation and set // to a different value upon initialization. enum BindingFlags { MUTABLE_IS_INITIALIZED, MUTABLE_CHECK_INITIALIZED, IMMUTABLE_IS_INITIALIZED, IMMUTABLE_CHECK_INITIALIZED, IMMUTABLE_IS_INITIALIZED_HARMONY, IMMUTABLE_CHECK_INITIALIZED_HARMONY, MISSING_BINDING }; // Heap-allocated activation contexts. // // Contexts are implemented as FixedArray objects; the Context // class is a convenience interface casted on a FixedArray object. // // Note: Context must have no virtual functions and Context objects // must always be allocated via Heap::AllocateContext() or // Factory::NewContext. #define NATIVE_CONTEXT_FIELDS(V) \ V(GLOBAL_PROXY_INDEX, JSObject, global_proxy_object) \ V(SECURITY_TOKEN_INDEX, Object, security_token) \ V(BOOLEAN_FUNCTION_INDEX, JSFunction, boolean_function) \ V(NUMBER_FUNCTION_INDEX, JSFunction, number_function) \ V(STRING_FUNCTION_INDEX, JSFunction, string_function) \ V(STRING_FUNCTION_PROTOTYPE_MAP_INDEX, Map, string_function_prototype_map) \ V(SYMBOL_FUNCTION_INDEX, JSFunction, symbol_function) \ V(OBJECT_FUNCTION_INDEX, JSFunction, object_function) \ V(INTERNAL_ARRAY_FUNCTION_INDEX, JSFunction, internal_array_function) \ V(ARRAY_FUNCTION_INDEX, JSFunction, array_function) \ V(JS_ARRAY_MAPS_INDEX, Object, js_array_maps) \ V(DATE_FUNCTION_INDEX, JSFunction, date_function) \ V(JSON_OBJECT_INDEX, JSObject, json_object) \ V(REGEXP_FUNCTION_INDEX, JSFunction, regexp_function) \ V(INITIAL_OBJECT_PROTOTYPE_INDEX, JSObject, initial_object_prototype) \ V(INITIAL_ARRAY_PROTOTYPE_INDEX, JSObject, initial_array_prototype) \ V(CREATE_DATE_FUN_INDEX, JSFunction, create_date_fun) \ V(TO_NUMBER_FUN_INDEX, JSFunction, to_number_fun) \ V(TO_STRING_FUN_INDEX, JSFunction, to_string_fun) \ V(TO_DETAIL_STRING_FUN_INDEX, JSFunction, to_detail_string_fun) \ V(TO_OBJECT_FUN_INDEX, JSFunction, to_object_fun) \ V(TO_INTEGER_FUN_INDEX, JSFunction, to_integer_fun) \ V(TO_UINT32_FUN_INDEX, JSFunction, to_uint32_fun) \ V(TO_INT32_FUN_INDEX, JSFunction, to_int32_fun) \ V(GLOBAL_EVAL_FUN_INDEX, JSFunction, global_eval_fun) \ V(INSTANTIATE_FUN_INDEX, JSFunction, instantiate_fun) \ V(CONFIGURE_INSTANCE_FUN_INDEX, JSFunction, configure_instance_fun) \ V(ARRAY_BUFFER_FUN_INDEX, JSFunction, array_buffer_fun) \ V(UINT8_ARRAY_FUN_INDEX, JSFunction, uint8_array_fun) \ V(INT8_ARRAY_FUN_INDEX, JSFunction, int8_array_fun) \ V(UINT16_ARRAY_FUN_INDEX, JSFunction, uint16_array_fun) \ V(INT16_ARRAY_FUN_INDEX, JSFunction, int16_array_fun) \ V(UINT32_ARRAY_FUN_INDEX, JSFunction, uint32_array_fun) \ V(INT32_ARRAY_FUN_INDEX, JSFunction, int32_array_fun) \ V(FLOAT32_ARRAY_FUN_INDEX, JSFunction, float32_array_fun) \ V(FLOAT64_ARRAY_FUN_INDEX, JSFunction, float64_array_fun) \ V(UINT8_CLAMPED_ARRAY_FUN_INDEX, JSFunction, uint8_clamped_array_fun) \ V(INT8_ARRAY_EXTERNAL_MAP_INDEX, Map, int8_array_external_map) \ V(UINT8_ARRAY_EXTERNAL_MAP_INDEX, Map, uint8_array_external_map) \ V(INT16_ARRAY_EXTERNAL_MAP_INDEX, Map, int16_array_external_map) \ V(UINT16_ARRAY_EXTERNAL_MAP_INDEX, Map, uint16_array_external_map) \ V(INT32_ARRAY_EXTERNAL_MAP_INDEX, Map, int32_array_external_map) \ V(UINT32_ARRAY_EXTERNAL_MAP_INDEX, Map, uint32_array_external_map) \ V(FLOAT32_ARRAY_EXTERNAL_MAP_INDEX, Map, float32_array_external_map) \ V(FLOAT64_ARRAY_EXTERNAL_MAP_INDEX, Map, float64_array_external_map) \ V(UINT8_CLAMPED_ARRAY_EXTERNAL_MAP_INDEX, Map, \ uint8_clamped_array_external_map) \ V(DATA_VIEW_FUN_INDEX, JSFunction, data_view_fun) \ V(SLOPPY_FUNCTION_MAP_INDEX, Map, sloppy_function_map) \ V(SLOPPY_FUNCTION_WITH_READONLY_PROTOTYPE_MAP_INDEX, Map, \ sloppy_function_with_readonly_prototype_map) \ V(STRICT_FUNCTION_MAP_INDEX, Map, strict_function_map) \ V(SLOPPY_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, Map, \ sloppy_function_without_prototype_map) \ V(STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, Map, \ strict_function_without_prototype_map) \ V(REGEXP_RESULT_MAP_INDEX, Map, regexp_result_map)\ V(SLOPPY_ARGUMENTS_BOILERPLATE_INDEX, JSObject, \ sloppy_arguments_boilerplate) \ V(ALIASED_ARGUMENTS_BOILERPLATE_INDEX, JSObject, \ aliased_arguments_boilerplate) \ V(STRICT_ARGUMENTS_BOILERPLATE_INDEX, JSObject, \ strict_arguments_boilerplate) \ V(MESSAGE_LISTENERS_INDEX, JSObject, message_listeners) \ V(MAKE_MESSAGE_FUN_INDEX, JSFunction, make_message_fun) \ V(GET_STACK_TRACE_LINE_INDEX, JSFunction, get_stack_trace_line_fun) \ V(CONFIGURE_GLOBAL_INDEX, JSFunction, configure_global_fun) \ V(FUNCTION_CACHE_INDEX, JSObject, function_cache) \ V(JSFUNCTION_RESULT_CACHES_INDEX, FixedArray, jsfunction_result_caches) \ V(NORMALIZED_MAP_CACHE_INDEX, NormalizedMapCache, normalized_map_cache) \ V(RUNTIME_CONTEXT_INDEX, Context, runtime_context) \ V(CALL_AS_FUNCTION_DELEGATE_INDEX, JSFunction, call_as_function_delegate) \ V(CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, JSFunction, \ call_as_constructor_delegate) \ V(SCRIPT_FUNCTION_INDEX, JSFunction, script_function) \ V(OPAQUE_REFERENCE_FUNCTION_INDEX, JSFunction, opaque_reference_function) \ V(CONTEXT_EXTENSION_FUNCTION_INDEX, JSFunction, context_extension_function) \ V(MAP_CACHE_INDEX, Object, map_cache) \ V(EMBEDDER_DATA_INDEX, FixedArray, embedder_data) \ V(ALLOW_CODE_GEN_FROM_STRINGS_INDEX, Object, allow_code_gen_from_strings) \ V(ERROR_MESSAGE_FOR_CODE_GEN_FROM_STRINGS_INDEX, Object, \ error_message_for_code_gen_from_strings) \ V(IS_PROMISE_INDEX, JSFunction, is_promise) \ V(PROMISE_CREATE_INDEX, JSFunction, promise_create) \ V(PROMISE_RESOLVE_INDEX, JSFunction, promise_resolve) \ V(PROMISE_REJECT_INDEX, JSFunction, promise_reject) \ V(PROMISE_CHAIN_INDEX, JSFunction, promise_chain) \ V(PROMISE_CATCH_INDEX, JSFunction, promise_catch) \ V(PROMISE_THEN_INDEX, JSFunction, promise_then) \ V(TO_COMPLETE_PROPERTY_DESCRIPTOR_INDEX, JSFunction, \ to_complete_property_descriptor) \ V(DERIVED_HAS_TRAP_INDEX, JSFunction, derived_has_trap) \ V(DERIVED_GET_TRAP_INDEX, JSFunction, derived_get_trap) \ V(DERIVED_SET_TRAP_INDEX, JSFunction, derived_set_trap) \ V(PROXY_ENUMERATE_INDEX, JSFunction, proxy_enumerate) \ V(OBSERVERS_NOTIFY_CHANGE_INDEX, JSFunction, observers_notify_change) \ V(OBSERVERS_ENQUEUE_SPLICE_INDEX, JSFunction, observers_enqueue_splice) \ V(OBSERVERS_BEGIN_SPLICE_INDEX, JSFunction, \ observers_begin_perform_splice) \ V(OBSERVERS_END_SPLICE_INDEX, JSFunction, \ observers_end_perform_splice) \ V(NATIVE_OBJECT_OBSERVE_INDEX, JSFunction, \ native_object_observe) \ V(NATIVE_OBJECT_GET_NOTIFIER_INDEX, JSFunction, \ native_object_get_notifier) \ V(NATIVE_OBJECT_NOTIFIER_PERFORM_CHANGE, JSFunction, \ native_object_notifier_perform_change) \ V(SLOPPY_GENERATOR_FUNCTION_MAP_INDEX, Map, sloppy_generator_function_map) \ V(STRICT_GENERATOR_FUNCTION_MAP_INDEX, Map, strict_generator_function_map) \ V(GENERATOR_OBJECT_PROTOTYPE_MAP_INDEX, Map, \ generator_object_prototype_map) \ V(ITERATOR_RESULT_MAP_INDEX, Map, iterator_result_map) \ V(MAP_ITERATOR_MAP_INDEX, Map, map_iterator_map) \ V(SET_ITERATOR_MAP_INDEX, Map, set_iterator_map) // JSFunctions are pairs (context, function code), sometimes also called // closures. A Context object is used to represent function contexts and // dynamically pushed 'with' contexts (or 'scopes' in ECMA-262 speak). // // At runtime, the contexts build a stack in parallel to the execution // stack, with the top-most context being the current context. All contexts // have the following slots: // // [ closure ] This is the current function. It is the same for all // contexts inside a function. It provides access to the // incoming context (i.e., the outer context, which may // or may not become the current function's context), and // it provides access to the functions code and thus it's // scope information, which in turn contains the names of // statically allocated context slots. The names are needed // for dynamic lookups in the presence of 'with' or 'eval'. // // [ previous ] A pointer to the previous context. It is NULL for // function contexts, and non-NULL for 'with' contexts. // Used to implement the 'with' statement. // // [ extension ] A pointer to an extension JSObject, or NULL. Used to // implement 'with' statements and dynamic declarations // (through 'eval'). The object in a 'with' statement is // stored in the extension slot of a 'with' context. // Dynamically declared variables/functions are also added // to lazily allocated extension object. Context::Lookup // searches the extension object for properties. // For global and block contexts, contains the respective // ScopeInfo. // For module contexts, points back to the respective JSModule. // // [ global_object ] A pointer to the global object. Provided for quick // access to the global object from inside the code (since // we always have a context pointer). // // In addition, function contexts may have statically allocated context slots // to store local variables/functions that are accessed from inner functions // (via static context addresses) or through 'eval' (dynamic context lookups). // The native context contains additional slots for fast access to native // properties. // // Finally, with Harmony scoping, the JSFunction representing a top level // script will have the GlobalContext rather than a FunctionContext. class Context: public FixedArray { public: // Conversions. static Context* cast(Object* context) { ASSERT(context->IsContext()); return reinterpret_cast(context); } // The default context slot layout; indices are FixedArray slot indices. enum { // These slots are in all contexts. CLOSURE_INDEX, PREVIOUS_INDEX, // The extension slot is used for either the global object (in global // contexts), eval extension object (function contexts), subject of with // (with contexts), or the variable name (catch contexts), the serialized // scope info (block contexts), or the module instance (module contexts). EXTENSION_INDEX, GLOBAL_OBJECT_INDEX, MIN_CONTEXT_SLOTS, // This slot holds the thrown value in catch contexts. THROWN_OBJECT_INDEX = MIN_CONTEXT_SLOTS, // These slots are only in native contexts. GLOBAL_PROXY_INDEX = MIN_CONTEXT_SLOTS, SECURITY_TOKEN_INDEX, SLOPPY_ARGUMENTS_BOILERPLATE_INDEX, ALIASED_ARGUMENTS_BOILERPLATE_INDEX, STRICT_ARGUMENTS_BOILERPLATE_INDEX, REGEXP_RESULT_MAP_INDEX, SLOPPY_FUNCTION_MAP_INDEX, SLOPPY_FUNCTION_WITH_READONLY_PROTOTYPE_MAP_INDEX, STRICT_FUNCTION_MAP_INDEX, SLOPPY_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, INITIAL_OBJECT_PROTOTYPE_INDEX, INITIAL_ARRAY_PROTOTYPE_INDEX, BOOLEAN_FUNCTION_INDEX, NUMBER_FUNCTION_INDEX, STRING_FUNCTION_INDEX, STRING_FUNCTION_PROTOTYPE_MAP_INDEX, SYMBOL_FUNCTION_INDEX, OBJECT_FUNCTION_INDEX, INTERNAL_ARRAY_FUNCTION_INDEX, ARRAY_FUNCTION_INDEX, JS_ARRAY_MAPS_INDEX, DATE_FUNCTION_INDEX, JSON_OBJECT_INDEX, REGEXP_FUNCTION_INDEX, CREATE_DATE_FUN_INDEX, TO_NUMBER_FUN_INDEX, TO_STRING_FUN_INDEX, TO_DETAIL_STRING_FUN_INDEX, TO_OBJECT_FUN_INDEX, TO_INTEGER_FUN_INDEX, TO_UINT32_FUN_INDEX, TO_INT32_FUN_INDEX, TO_BOOLEAN_FUN_INDEX, GLOBAL_EVAL_FUN_INDEX, INSTANTIATE_FUN_INDEX, CONFIGURE_INSTANCE_FUN_INDEX, ARRAY_BUFFER_FUN_INDEX, UINT8_ARRAY_FUN_INDEX, INT8_ARRAY_FUN_INDEX, UINT16_ARRAY_FUN_INDEX, INT16_ARRAY_FUN_INDEX, UINT32_ARRAY_FUN_INDEX, INT32_ARRAY_FUN_INDEX, FLOAT32_ARRAY_FUN_INDEX, FLOAT64_ARRAY_FUN_INDEX, UINT8_CLAMPED_ARRAY_FUN_INDEX, INT8_ARRAY_EXTERNAL_MAP_INDEX, UINT8_ARRAY_EXTERNAL_MAP_INDEX, INT16_ARRAY_EXTERNAL_MAP_INDEX, UINT16_ARRAY_EXTERNAL_MAP_INDEX, INT32_ARRAY_EXTERNAL_MAP_INDEX, UINT32_ARRAY_EXTERNAL_MAP_INDEX, FLOAT32_ARRAY_EXTERNAL_MAP_INDEX, FLOAT64_ARRAY_EXTERNAL_MAP_INDEX, UINT8_CLAMPED_ARRAY_EXTERNAL_MAP_INDEX, DATA_VIEW_FUN_INDEX, MESSAGE_LISTENERS_INDEX, MAKE_MESSAGE_FUN_INDEX, GET_STACK_TRACE_LINE_INDEX, CONFIGURE_GLOBAL_INDEX, FUNCTION_CACHE_INDEX, JSFUNCTION_RESULT_CACHES_INDEX, NORMALIZED_MAP_CACHE_INDEX, RUNTIME_CONTEXT_INDEX, CALL_AS_FUNCTION_DELEGATE_INDEX, CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, SCRIPT_FUNCTION_INDEX, OPAQUE_REFERENCE_FUNCTION_INDEX, CONTEXT_EXTENSION_FUNCTION_INDEX, OUT_OF_MEMORY_INDEX, EMBEDDER_DATA_INDEX, ALLOW_CODE_GEN_FROM_STRINGS_INDEX, ERROR_MESSAGE_FOR_CODE_GEN_FROM_STRINGS_INDEX, RUN_MICROTASKS_INDEX, ENQUEUE_MICROTASK_INDEX, IS_PROMISE_INDEX, PROMISE_CREATE_INDEX, PROMISE_RESOLVE_INDEX, PROMISE_REJECT_INDEX, PROMISE_CHAIN_INDEX, PROMISE_CATCH_INDEX, PROMISE_THEN_INDEX, TO_COMPLETE_PROPERTY_DESCRIPTOR_INDEX, DERIVED_HAS_TRAP_INDEX, DERIVED_GET_TRAP_INDEX, DERIVED_SET_TRAP_INDEX, PROXY_ENUMERATE_INDEX, OBSERVERS_NOTIFY_CHANGE_INDEX, OBSERVERS_ENQUEUE_SPLICE_INDEX, OBSERVERS_BEGIN_SPLICE_INDEX, OBSERVERS_END_SPLICE_INDEX, NATIVE_OBJECT_OBSERVE_INDEX, NATIVE_OBJECT_GET_NOTIFIER_INDEX, NATIVE_OBJECT_NOTIFIER_PERFORM_CHANGE, SLOPPY_GENERATOR_FUNCTION_MAP_INDEX, STRICT_GENERATOR_FUNCTION_MAP_INDEX, GENERATOR_OBJECT_PROTOTYPE_MAP_INDEX, ITERATOR_RESULT_MAP_INDEX, MAP_ITERATOR_MAP_INDEX, SET_ITERATOR_MAP_INDEX, // Properties from here are treated as weak references by the full GC. // Scavenge treats them as strong references. OPTIMIZED_FUNCTIONS_LIST, // Weak. OPTIMIZED_CODE_LIST, // Weak. DEOPTIMIZED_CODE_LIST, // Weak. MAP_CACHE_INDEX, // Weak. NEXT_CONTEXT_LINK, // Weak. // Total number of slots. NATIVE_CONTEXT_SLOTS, FIRST_WEAK_SLOT = OPTIMIZED_FUNCTIONS_LIST }; // Direct slot access. JSFunction* closure() { return JSFunction::cast(get(CLOSURE_INDEX)); } void set_closure(JSFunction* closure) { set(CLOSURE_INDEX, closure); } Context* previous() { Object* result = unchecked_previous(); ASSERT(IsBootstrappingOrValidParentContext(result, this)); return reinterpret_cast(result); } void set_previous(Context* context) { set(PREVIOUS_INDEX, context); } bool has_extension() { return extension() != NULL; } Object* extension() { return get(EXTENSION_INDEX); } void set_extension(Object* object) { set(EXTENSION_INDEX, object); } JSModule* module() { return JSModule::cast(get(EXTENSION_INDEX)); } void set_module(JSModule* module) { set(EXTENSION_INDEX, module); } // Get the context where var declarations will be hoisted to, which // may be the context itself. Context* declaration_context(); GlobalObject* global_object() { Object* result = get(GLOBAL_OBJECT_INDEX); ASSERT(IsBootstrappingOrGlobalObject(this->GetIsolate(), result)); return reinterpret_cast(result); } void set_global_object(GlobalObject* object) { set(GLOBAL_OBJECT_INDEX, object); } // Returns a JSGlobalProxy object or null. JSObject* global_proxy(); void set_global_proxy(JSObject* global); // The builtins object. JSBuiltinsObject* builtins(); // Get the innermost global context by traversing the context chain. Context* global_context(); // Compute the native context by traversing the context chain. Context* native_context(); // Predicates for context types. IsNativeContext is also defined on Object // because we frequently have to know if arbitrary objects are natives // contexts. bool IsNativeContext() { Map* map = this->map(); return map == map->GetHeap()->native_context_map(); } bool IsFunctionContext() { Map* map = this->map(); return map == map->GetHeap()->function_context_map(); } bool IsCatchContext() { Map* map = this->map(); return map == map->GetHeap()->catch_context_map(); } bool IsWithContext() { Map* map = this->map(); return map == map->GetHeap()->with_context_map(); } bool IsBlockContext() { Map* map = this->map(); return map == map->GetHeap()->block_context_map(); } bool IsModuleContext() { Map* map = this->map(); return map == map->GetHeap()->module_context_map(); } bool IsGlobalContext() { Map* map = this->map(); return map == map->GetHeap()->global_context_map(); } bool HasSameSecurityTokenAs(Context* that) { return this->global_object()->native_context()->security_token() == that->global_object()->native_context()->security_token(); } // A native context holds a list of all functions with optimized code. void AddOptimizedFunction(JSFunction* function); void RemoveOptimizedFunction(JSFunction* function); void SetOptimizedFunctionsListHead(Object* head); Object* OptimizedFunctionsListHead(); // The native context also stores a list of all optimized code and a // list of all deoptimized code, which are needed by the deoptimizer. void AddOptimizedCode(Code* code); void SetOptimizedCodeListHead(Object* head); Object* OptimizedCodeListHead(); void SetDeoptimizedCodeListHead(Object* head); Object* DeoptimizedCodeListHead(); Handle ErrorMessageForCodeGenerationFromStrings(); #define NATIVE_CONTEXT_FIELD_ACCESSORS(index, type, name) \ void set_##name(type* value) { \ ASSERT(IsNativeContext()); \ set(index, value); \ } \ bool is_##name(type* value) { \ ASSERT(IsNativeContext()); \ return type::cast(get(index)) == value; \ } \ type* name() { \ ASSERT(IsNativeContext()); \ return type::cast(get(index)); \ } NATIVE_CONTEXT_FIELDS(NATIVE_CONTEXT_FIELD_ACCESSORS) #undef NATIVE_CONTEXT_FIELD_ACCESSORS // Lookup the slot called name, starting with the current context. // There are three possibilities: // // 1) result->IsContext(): // The binding was found in a context. *index is always the // non-negative slot index. *attributes is NONE for var and let // declarations, READ_ONLY for const declarations (never ABSENT). // // 2) result->IsJSObject(): // The binding was found as a named property in a context extension // object (i.e., was introduced via eval), as a property on the subject // of with, or as a property of the global object. *index is -1 and // *attributes is not ABSENT. // // 3) result.is_null(): // There was no binding found, *index is always -1 and *attributes is // always ABSENT. Handle Lookup(Handle name, ContextLookupFlags flags, int* index, PropertyAttributes* attributes, BindingFlags* binding_flags); // Code generation support. static int SlotOffset(int index) { return kHeaderSize + index * kPointerSize - kHeapObjectTag; } static int FunctionMapIndex(StrictMode strict_mode, bool is_generator) { return is_generator ? (strict_mode == SLOPPY ? SLOPPY_GENERATOR_FUNCTION_MAP_INDEX : STRICT_GENERATOR_FUNCTION_MAP_INDEX) : (strict_mode == SLOPPY ? SLOPPY_FUNCTION_MAP_INDEX : STRICT_FUNCTION_MAP_INDEX); } static const int kSize = kHeaderSize + NATIVE_CONTEXT_SLOTS * kPointerSize; // GC support. typedef FixedBodyDescriptor< kHeaderSize, kSize, kSize> ScavengeBodyDescriptor; typedef FixedBodyDescriptor< kHeaderSize, kHeaderSize + FIRST_WEAK_SLOT * kPointerSize, kSize> MarkCompactBodyDescriptor; private: // Unchecked access to the slots. Object* unchecked_previous() { return get(PREVIOUS_INDEX); } #ifdef DEBUG // Bootstrapping-aware type checks. static bool IsBootstrappingOrValidParentContext(Object* object, Context* kid); static bool IsBootstrappingOrGlobalObject(Isolate* isolate, Object* object); #endif STATIC_ASSERT(kHeaderSize == Internals::kContextHeaderSize); STATIC_ASSERT(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex); }; } } // namespace v8::internal #endif // V8_CONTEXTS_H_