| // Copyright 2012 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef V8_CONTEXTS_H_ |
| #define V8_CONTEXTS_H_ |
| |
| #include "heap.h" |
| #include "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(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(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(FUNCTION_MAP_INDEX, Map, function_map) \ |
| V(STRICT_MODE_FUNCTION_MAP_INDEX, Map, strict_mode_function_map) \ |
| V(FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, Map, function_without_prototype_map) \ |
| V(STRICT_MODE_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, Map, \ |
| strict_mode_function_without_prototype_map) \ |
| V(FUNCTION_INSTANCE_MAP_INDEX, Map, function_instance_map) \ |
| V(STRICT_MODE_FUNCTION_INSTANCE_MAP_INDEX, Map, \ |
| strict_mode_function_instance_map) \ |
| V(REGEXP_RESULT_MAP_INDEX, Map, regexp_result_map)\ |
| V(ARGUMENTS_BOILERPLATE_INDEX, JSObject, arguments_boilerplate) \ |
| V(ALIASED_ARGUMENTS_BOILERPLATE_INDEX, JSObject, \ |
| aliased_arguments_boilerplate) \ |
| V(STRICT_MODE_ARGUMENTS_BOILERPLATE_INDEX, JSObject, \ |
| strict_mode_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(OUT_OF_MEMORY_INDEX, Object, out_of_memory) \ |
| 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(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_DELIVER_CHANGES_INDEX, JSFunction, observers_deliver_changes) \ |
| V(RANDOM_SEED_INDEX, ByteArray, random_seed) |
| |
| // 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). |
| // Finally, the native context contains additional slots for fast access to |
| // native properties. |
| |
| class Context: public FixedArray { |
| public: |
| // Conversions. |
| static Context* cast(Object* context) { |
| ASSERT(context->IsContext()); |
| return reinterpret_cast<Context*>(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, |
| ARGUMENTS_BOILERPLATE_INDEX, |
| ALIASED_ARGUMENTS_BOILERPLATE_INDEX, |
| STRICT_MODE_ARGUMENTS_BOILERPLATE_INDEX, |
| REGEXP_RESULT_MAP_INDEX, |
| FUNCTION_MAP_INDEX, |
| STRICT_MODE_FUNCTION_MAP_INDEX, |
| FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, |
| STRICT_MODE_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, |
| FUNCTION_INSTANCE_MAP_INDEX, |
| STRICT_MODE_FUNCTION_INSTANCE_MAP_INDEX, |
| INITIAL_OBJECT_PROTOTYPE_INDEX, |
| BOOLEAN_FUNCTION_INDEX, |
| NUMBER_FUNCTION_INDEX, |
| STRING_FUNCTION_INDEX, |
| STRING_FUNCTION_PROTOTYPE_MAP_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, |
| 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, |
| 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_DELIVER_CHANGES_INDEX, |
| RANDOM_SEED_INDEX, |
| |
| // Properties from here are treated as weak references by the full GC. |
| // Scavenge treats them as strong references. |
| OPTIMIZED_FUNCTIONS_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<Context*>(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(result)); |
| return reinterpret_cast<GlobalObject*>(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 defined on Object |
| // because we frequently have to know if arbitrary objects are natives |
| // contexts. |
| 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(); |
| } |
| |
| // Tells whether the native context is marked with out of memory. |
| inline bool has_out_of_memory(); |
| |
| // Mark the native context with out of memory. |
| inline void mark_out_of_memory(); |
| |
| // A native context hold a list of all functions which have been optimized. |
| void AddOptimizedFunction(JSFunction* function); |
| void RemoveOptimizedFunction(JSFunction* function); |
| Object* OptimizedFunctionsListHead(); |
| void ClearOptimizedFunctions(); |
| |
| Handle<Object> ErrorMessageForCodeGenerationFromStrings(); |
| |
| #define NATIVE_CONTEXT_FIELD_ACCESSORS(index, type, name) \ |
| void set_##name(type* value) { \ |
| ASSERT(IsNativeContext()); \ |
| set(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<Object> Lookup(Handle<String> name, |
| ContextLookupFlags flags, |
| int* index, |
| PropertyAttributes* attributes, |
| BindingFlags* binding_flags); |
| |
| // Code generation support. |
| static int SlotOffset(int index) { |
| return kHeaderSize + index * kPointerSize - kHeapObjectTag; |
| } |
| |
| 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(Object* object); |
| #endif |
| |
| STATIC_CHECK(kHeaderSize == Internals::kContextHeaderSize); |
| STATIC_CHECK(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex); |
| }; |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_CONTEXTS_H_ |