// 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/heap.h"
#include "src/objects.h"
namespace v8 {
namespace internal {
enum ContextLookupFlags {
FOLLOW_CONTEXT_CHAIN = 1 << 0,
FOLLOW_PROTOTYPE_CHAIN = 1 << 1,
STOP_AT_DECLARATION_SCOPE = 1 << 2,
SKIP_WITH_CONTEXT = 1 << 3,
DONT_FOLLOW_CHAINS = 0,
FOLLOW_CHAINS = FOLLOW_CONTEXT_CHAIN | FOLLOW_PROTOTYPE_CHAIN,
LEXICAL_TEST =
FOLLOW_CONTEXT_CHAIN | STOP_AT_DECLARATION_SCOPE | SKIP_WITH_CONTEXT,
};
// 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_INTRINSIC_FUNCTIONS(V) \
V(IS_ARRAYLIKE, JSFunction, is_arraylike) \
V(CONCAT_ITERABLE_TO_ARRAY_INDEX, JSFunction, concat_iterable_to_array) \
V(GET_TEMPLATE_CALL_SITE_INDEX, JSFunction, get_template_call_site) \
V(MAKE_RANGE_ERROR_INDEX, JSFunction, make_range_error) \
V(MAKE_TYPE_ERROR_INDEX, JSFunction, make_type_error) \
V(OBJECT_FREEZE, JSFunction, object_freeze) \
V(OBJECT_IS_EXTENSIBLE, JSFunction, object_is_extensible) \
V(OBJECT_IS_FROZEN, JSFunction, object_is_frozen) \
V(OBJECT_IS_SEALED, JSFunction, object_is_sealed) \
V(OBJECT_KEYS, JSFunction, object_keys) \
V(REFLECT_APPLY_INDEX, JSFunction, reflect_apply) \
V(REFLECT_CONSTRUCT_INDEX, JSFunction, reflect_construct) \
V(REFLECT_DEFINE_PROPERTY_INDEX, JSFunction, reflect_define_property) \
V(REFLECT_DELETE_PROPERTY_INDEX, JSFunction, reflect_delete_property) \
V(SPREAD_ARGUMENTS_INDEX, JSFunction, spread_arguments) \
V(SPREAD_ITERABLE_INDEX, JSFunction, spread_iterable)
#define NATIVE_CONTEXT_JS_BUILTINS(V) \
V(CONCAT_ITERABLE_TO_ARRAY_BUILTIN_INDEX, JSFunction, \
concat_iterable_to_array_builtin)
#define NATIVE_CONTEXT_IMPORTED_FIELDS(V) \
V(ARRAY_CONCAT_INDEX, JSFunction, array_concat) \
V(ARRAY_POP_INDEX, JSFunction, array_pop) \
V(ARRAY_PUSH_INDEX, JSFunction, array_push) \
V(ARRAY_SHIFT_INDEX, JSFunction, array_shift) \
V(ARRAY_SPLICE_INDEX, JSFunction, array_splice) \
V(ARRAY_SLICE_INDEX, JSFunction, array_slice) \
V(ARRAY_UNSHIFT_INDEX, JSFunction, array_unshift) \
V(ARRAY_VALUES_ITERATOR_INDEX, JSFunction, array_values_iterator) \
V(DERIVED_GET_TRAP_INDEX, JSFunction, derived_get_trap) \
V(ERROR_FUNCTION_INDEX, JSFunction, error_function) \
V(EVAL_ERROR_FUNCTION_INDEX, JSFunction, eval_error_function) \
V(GET_STACK_TRACE_LINE_INDEX, JSFunction, get_stack_trace_line_fun) \
V(GLOBAL_EVAL_FUN_INDEX, JSFunction, global_eval_fun) \
V(JSON_SERIALIZE_ADAPTER_INDEX, JSFunction, json_serialize_adapter) \
V(MAKE_ERROR_FUNCTION_INDEX, JSFunction, make_error_function) \
V(MAP_DELETE_METHOD_INDEX, JSFunction, map_delete) \
V(MAP_GET_METHOD_INDEX, JSFunction, map_get) \
V(MAP_HAS_METHOD_INDEX, JSFunction, map_has) \
V(MAP_SET_METHOD_INDEX, JSFunction, map_set) \
V(MESSAGE_GET_COLUMN_NUMBER_INDEX, JSFunction, message_get_column_number) \
V(MESSAGE_GET_LINE_NUMBER_INDEX, JSFunction, message_get_line_number) \
V(MESSAGE_GET_SOURCE_LINE_INDEX, JSFunction, message_get_source_line) \
V(NATIVE_OBJECT_GET_NOTIFIER_INDEX, JSFunction, native_object_get_notifier) \
V(NATIVE_OBJECT_NOTIFIER_PERFORM_CHANGE, JSFunction, \
native_object_notifier_perform_change) \
V(NATIVE_OBJECT_OBSERVE_INDEX, JSFunction, native_object_observe) \
V(NO_SIDE_EFFECTS_TO_STRING_FUN_INDEX, JSFunction, \
no_side_effects_to_string_fun) \
V(OBJECT_VALUE_OF, JSFunction, object_value_of) \
V(OBJECT_TO_STRING, JSFunction, object_to_string) \
V(OBSERVERS_BEGIN_SPLICE_INDEX, JSFunction, observers_begin_perform_splice) \
V(OBSERVERS_END_SPLICE_INDEX, JSFunction, observers_end_perform_splice) \
V(OBSERVERS_ENQUEUE_SPLICE_INDEX, JSFunction, observers_enqueue_splice) \
V(OBSERVERS_NOTIFY_CHANGE_INDEX, JSFunction, observers_notify_change) \
V(PROMISE_CATCH_INDEX, JSFunction, promise_catch) \
V(PROMISE_CHAIN_INDEX, JSFunction, promise_chain) \
V(PROMISE_CREATE_INDEX, JSFunction, promise_create) \
V(PROMISE_FUNCTION_INDEX, JSFunction, promise_function) \
V(PROMISE_HAS_USER_DEFINED_REJECT_HANDLER_INDEX, JSFunction, \
promise_has_user_defined_reject_handler) \
V(PROMISE_REJECT_INDEX, JSFunction, promise_reject) \
V(PROMISE_RESOLVE_INDEX, JSFunction, promise_resolve) \
V(PROMISE_THEN_INDEX, JSFunction, promise_then) \
V(PROXY_ENUMERATE_INDEX, JSFunction, proxy_enumerate) \
V(RANGE_ERROR_FUNCTION_INDEX, JSFunction, range_error_function) \
V(REFERENCE_ERROR_FUNCTION_INDEX, JSFunction, reference_error_function) \
V(SET_ADD_METHOD_INDEX, JSFunction, set_add) \
V(SET_DELETE_METHOD_INDEX, JSFunction, set_delete) \
V(SET_HAS_METHOD_INDEX, JSFunction, set_has) \
V(STACK_OVERFLOW_BOILERPLATE_INDEX, JSObject, stack_overflow_boilerplate) \
V(SYNTAX_ERROR_FUNCTION_INDEX, JSFunction, syntax_error_function) \
V(TYPE_ERROR_FUNCTION_INDEX, JSFunction, type_error_function) \
V(URI_ERROR_FUNCTION_INDEX, JSFunction, uri_error_function) \
NATIVE_CONTEXT_JS_BUILTINS(V)
#define NATIVE_CONTEXT_FIELDS(V) \
V(GLOBAL_PROXY_INDEX, JSObject, global_proxy_object) \
V(EMBEDDER_DATA_INDEX, FixedArray, embedder_data) \
/* Below is alpha-sorted */ \
V(ALLOW_CODE_GEN_FROM_STRINGS_INDEX, Object, allow_code_gen_from_strings) \
V(ARRAY_BUFFER_FUN_INDEX, JSFunction, array_buffer_fun) \
V(ARRAY_BUFFER_MAP_INDEX, Map, array_buffer_map) \
V(ARRAY_FUNCTION_INDEX, JSFunction, array_function) \
V(BOOL16X8_FUNCTION_INDEX, JSFunction, bool16x8_function) \
V(BOOL32X4_FUNCTION_INDEX, JSFunction, bool32x4_function) \
V(BOOL8X16_FUNCTION_INDEX, JSFunction, bool8x16_function) \
V(BOOLEAN_FUNCTION_INDEX, JSFunction, boolean_function) \
V(BOUND_FUNCTION_WITH_CONSTRUCTOR_MAP_INDEX, Map, \
bound_function_with_constructor_map) \
V(BOUND_FUNCTION_WITHOUT_CONSTRUCTOR_MAP_INDEX, Map, \
bound_function_without_constructor_map) \
V(CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, JSFunction, \
call_as_constructor_delegate) \
V(CALL_AS_FUNCTION_DELEGATE_INDEX, JSFunction, call_as_function_delegate) \
V(CONTEXT_EXTENSION_FUNCTION_INDEX, JSFunction, context_extension_function) \
V(DATA_VIEW_FUN_INDEX, JSFunction, data_view_fun) \
V(DATE_FUNCTION_INDEX, JSFunction, date_function) \
V(ERROR_MESSAGE_FOR_CODE_GEN_FROM_STRINGS_INDEX, Object, \
error_message_for_code_gen_from_strings) \
V(ERRORS_THROWN_INDEX, Smi, errors_thrown) \
V(EXTRAS_EXPORTS_OBJECT_INDEX, JSObject, extras_binding_object) \
V(EXTRAS_UTILS_OBJECT_INDEX, JSObject, extras_utils_object) \
V(FAST_ALIASED_ARGUMENTS_MAP_INDEX, Map, fast_aliased_arguments_map) \
V(FLOAT32_ARRAY_FUN_INDEX, JSFunction, float32_array_fun) \
V(FLOAT32X4_FUNCTION_INDEX, JSFunction, float32x4_function) \
V(FLOAT64_ARRAY_FUN_INDEX, JSFunction, float64_array_fun) \
V(FUNCTION_CACHE_INDEX, ObjectHashTable, function_cache) \
V(FUNCTION_FUNCTION_INDEX, JSFunction, function_function) \
V(GENERATOR_FUNCTION_FUNCTION_INDEX, JSFunction, \
generator_function_function) \
V(GENERATOR_OBJECT_PROTOTYPE_MAP_INDEX, Map, generator_object_prototype_map) \
V(INITIAL_ARRAY_PROTOTYPE_INDEX, JSObject, initial_array_prototype) \
V(INITIAL_OBJECT_PROTOTYPE_INDEX, JSObject, initial_object_prototype) \
V(INT16_ARRAY_FUN_INDEX, JSFunction, int16_array_fun) \
V(INT16X8_FUNCTION_INDEX, JSFunction, int16x8_function) \
V(INT32_ARRAY_FUN_INDEX, JSFunction, int32_array_fun) \
V(INT32X4_FUNCTION_INDEX, JSFunction, int32x4_function) \
V(INT8_ARRAY_FUN_INDEX, JSFunction, int8_array_fun) \
V(INT8X16_FUNCTION_INDEX, JSFunction, int8x16_function) \
V(INTERNAL_ARRAY_FUNCTION_INDEX, JSFunction, internal_array_function) \
V(ITERATOR_RESULT_MAP_INDEX, Map, iterator_result_map) \
V(JS_ARRAY_FAST_SMI_ELEMENTS_MAP_INDEX, Map, \
js_array_fast_smi_elements_map_index) \
V(JS_ARRAY_FAST_HOLEY_SMI_ELEMENTS_MAP_INDEX, Map, \
js_array_fast_holey_smi_elements_map_index) \
V(JS_ARRAY_FAST_ELEMENTS_MAP_INDEX, Map, js_array_fast_elements_map_index) \
V(JS_ARRAY_FAST_HOLEY_ELEMENTS_MAP_INDEX, Map, \
js_array_fast_holey_elements_map_index) \
V(JS_ARRAY_FAST_DOUBLE_ELEMENTS_MAP_INDEX, Map, \
js_array_fast_double_elements_map_index) \
V(JS_ARRAY_FAST_HOLEY_DOUBLE_ELEMENTS_MAP_INDEX, Map, \
js_array_fast_holey_double_elements_map_index) \
V(JS_ARRAY_FAST_SMI_ELEMENTS_STRONG_MAP_INDEX, Map, \
js_array_fast_smi_elements_strong_map_index) \
V(JS_ARRAY_FAST_HOLEY_SMI_ELEMENTS_STRONG_MAP_INDEX, Map, \
js_array_fast_holey_smi_elements_strong_map_index) \
V(JS_ARRAY_FAST_ELEMENTS_STRONG_MAP_INDEX, Map, \
js_array_fast_elements_strong_map_index) \
V(JS_ARRAY_FAST_HOLEY_ELEMENTS_STRONG_MAP_INDEX, Map, \
js_array_fast_holey_elements_strong_map_index) \
V(JS_ARRAY_FAST_DOUBLE_ELEMENTS_STRONG_MAP_INDEX, Map, \
js_array_fast_double_elements_strong_map_index) \
V(JS_ARRAY_FAST_HOLEY_DOUBLE_ELEMENTS_STRONG_MAP_INDEX, Map, \
js_array_fast_holey_double_elements_strong_map_index) \
V(JS_MAP_FUN_INDEX, JSFunction, js_map_fun) \
V(JS_MAP_MAP_INDEX, Map, js_map_map) \
V(JS_OBJECT_STRONG_MAP_INDEX, Map, js_object_strong_map) \
V(JS_SET_FUN_INDEX, JSFunction, js_set_fun) \
V(JS_SET_MAP_INDEX, Map, js_set_map) \
V(JS_WEAK_MAP_FUN_INDEX, JSFunction, js_weak_map_fun) \
V(JS_WEAK_SET_FUN_INDEX, JSFunction, js_weak_set_fun) \
V(MAP_CACHE_INDEX, Object, map_cache) \
V(MAP_ITERATOR_MAP_INDEX, Map, map_iterator_map) \
V(STRING_ITERATOR_MAP_INDEX, Map, string_iterator_map) \
V(MESSAGE_LISTENERS_INDEX, JSObject, message_listeners) \
V(NATIVES_UTILS_OBJECT_INDEX, Object, natives_utils_object) \
V(NORMALIZED_MAP_CACHE_INDEX, Object, normalized_map_cache) \
V(NUMBER_FUNCTION_INDEX, JSFunction, number_function) \
V(OBJECT_FUNCTION_INDEX, JSFunction, object_function) \
V(OBJECT_FUNCTION_PROTOTYPE_MAP_INDEX, Map, object_function_prototype_map) \
V(OPAQUE_REFERENCE_FUNCTION_INDEX, JSFunction, opaque_reference_function) \
V(PROXY_CALLABLE_MAP_INDEX, Map, proxy_callable_map) \
V(PROXY_CONSTRUCTOR_MAP_INDEX, Map, proxy_constructor_map) \
V(PROXY_FUNCTION_INDEX, JSFunction, proxy_function) \
V(PROXY_FUNCTION_MAP_INDEX, Map, proxy_function_map) \
V(PROXY_MAP_INDEX, Map, proxy_map) \
V(REGEXP_FUNCTION_INDEX, JSFunction, regexp_function) \
V(REGEXP_RESULT_MAP_INDEX, Map, regexp_result_map) \
V(SCRIPT_CONTEXT_TABLE_INDEX, ScriptContextTable, script_context_table) \
V(SCRIPT_FUNCTION_INDEX, JSFunction, script_function) \
V(SECURITY_TOKEN_INDEX, Object, security_token) \
V(SELF_WEAK_CELL_INDEX, WeakCell, self_weak_cell) \
V(SET_ITERATOR_MAP_INDEX, Map, set_iterator_map) \
V(SHARED_ARRAY_BUFFER_FUN_INDEX, JSFunction, shared_array_buffer_fun) \
V(SLOPPY_ARGUMENTS_MAP_INDEX, Map, sloppy_arguments_map) \
V(SLOPPY_FUNCTION_MAP_INDEX, Map, sloppy_function_map) \
V(SLOPPY_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, Map, \
sloppy_function_without_prototype_map) \
V(SLOPPY_FUNCTION_WITH_READONLY_PROTOTYPE_MAP_INDEX, Map, \
sloppy_function_with_readonly_prototype_map) \
V(WASM_FUNCTION_MAP_INDEX, Map, wasm_function_map) \
V(SLOPPY_GENERATOR_FUNCTION_MAP_INDEX, Map, sloppy_generator_function_map) \
V(SLOW_ALIASED_ARGUMENTS_MAP_INDEX, Map, slow_aliased_arguments_map) \
V(STRICT_ARGUMENTS_MAP_INDEX, Map, strict_arguments_map) \
V(STRICT_FUNCTION_MAP_INDEX, Map, strict_function_map) \
V(STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX, Map, \
strict_function_without_prototype_map) \
V(STRICT_GENERATOR_FUNCTION_MAP_INDEX, Map, strict_generator_function_map) \
V(STRING_FUNCTION_INDEX, JSFunction, string_function) \
V(STRING_FUNCTION_PROTOTYPE_MAP_INDEX, Map, string_function_prototype_map) \
V(STRONG_CONSTRUCTOR_MAP_INDEX, Map, strong_constructor_map) \
V(STRONG_FUNCTION_MAP_INDEX, Map, strong_function_map) \
V(STRONG_GENERATOR_FUNCTION_MAP_INDEX, Map, strong_generator_function_map) \
V(STRONG_MAP_CACHE_INDEX, Object, strong_map_cache) \
V(SYMBOL_FUNCTION_INDEX, JSFunction, symbol_function) \
V(UINT16_ARRAY_FUN_INDEX, JSFunction, uint16_array_fun) \
V(UINT16X8_FUNCTION_INDEX, JSFunction, uint16x8_function) \
V(UINT32_ARRAY_FUN_INDEX, JSFunction, uint32_array_fun) \
V(UINT32X4_FUNCTION_INDEX, JSFunction, uint32x4_function) \
V(UINT8_ARRAY_FUN_INDEX, JSFunction, uint8_array_fun) \
V(UINT8_CLAMPED_ARRAY_FUN_INDEX, JSFunction, uint8_clamped_array_fun) \
V(UINT8X16_FUNCTION_INDEX, JSFunction, uint8x16_function) \
NATIVE_CONTEXT_INTRINSIC_FUNCTIONS(V) \
NATIVE_CONTEXT_IMPORTED_FIELDS(V)
// A table of all script contexts. Every loaded top-level script with top-level
// lexical declarations contributes its ScriptContext into this table.
//
// The table is a fixed array, its first slot is the current used count and
// the subsequent slots 1..used contain ScriptContexts.
class ScriptContextTable : public FixedArray {
public:
// Conversions.
static inline ScriptContextTable* cast(Object* context);
struct LookupResult {
int context_index;
int slot_index;
VariableMode mode;
InitializationFlag init_flag;
MaybeAssignedFlag maybe_assigned_flag;
};
inline int used() const;
inline void set_used(int used);
static inline Handle<Context> GetContext(Handle<ScriptContextTable> table,
int i);
// Lookup a variable `name` in a ScriptContextTable.
// If it returns true, the variable is found and `result` contains
// valid information about its location.
// If it returns false, `result` is untouched.
MUST_USE_RESULT
static bool Lookup(Handle<ScriptContextTable> table, Handle<String> name,
LookupResult* result);
MUST_USE_RESULT
static Handle<ScriptContextTable> Extend(Handle<ScriptContextTable> table,
Handle<Context> script_context);
static int GetContextOffset(int context_index) {
return kFirstContextOffset + context_index * kPointerSize;
}
private:
static const int kUsedSlot = 0;
static const int kFirstContextSlot = kUsedSlot + 1;
static const int kFirstContextOffset =
FixedArray::kHeaderSize + kFirstContextSlot * kPointerSize;
DISALLOW_IMPLICIT_CONSTRUCTORS(ScriptContextTable);
};
// 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 "the hole". 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 script and block contexts, contains the respective
// ScopeInfo. For block contexts representing sloppy declaration
// block scopes, it may also be a struct being a
// SloppyBlockWithEvalContextExtension, pairing the ScopeInfo
// with an extension object.
// 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 ScriptContext rather than a FunctionContext.
// Script contexts from all top-level scripts are gathered in
// ScriptContextTable.
class Context: public FixedArray {
public:
// Conversions.
static inline Context* cast(Object* 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 native
// 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,
NATIVE_CONTEXT_INDEX,
// These slots are only in native contexts.
#define NATIVE_CONTEXT_SLOT(index, type, name) index,
NATIVE_CONTEXT_FIELDS(NATIVE_CONTEXT_SLOT)
#undef NATIVE_CONTEXT_SLOT
// 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.
NEXT_CONTEXT_LINK, // Weak.
// Total number of slots.
NATIVE_CONTEXT_SLOTS,
FIRST_WEAK_SLOT = OPTIMIZED_FUNCTIONS_LIST,
FIRST_JS_ARRAY_MAP_SLOT = JS_ARRAY_FAST_SMI_ELEMENTS_MAP_INDEX,
FIRST_JS_ARRAY_STRONG_MAP_SLOT =
JS_ARRAY_FAST_SMI_ELEMENTS_STRONG_MAP_INDEX,
MIN_CONTEXT_SLOTS = GLOBAL_PROXY_INDEX,
// This slot holds the thrown value in catch contexts.
THROWN_OBJECT_INDEX = MIN_CONTEXT_SLOTS,
};
void IncrementErrorsThrown();
int GetErrorsThrown();
// Direct slot access.
inline JSFunction* closure();
inline void set_closure(JSFunction* closure);
inline Context* previous();
inline void set_previous(Context* context);
inline bool has_extension();
inline HeapObject* extension();
inline void set_extension(HeapObject* object);
JSObject* extension_object();
JSReceiver* extension_receiver();
ScopeInfo* scope_info();
String* catch_name();
inline JSModule* module();
inline void set_module(JSModule* module);
// Get the context where var declarations will be hoisted to, which
// may be the context itself.
Context* declaration_context();
bool is_declaration_context();
// Returns a JSGlobalProxy object or null.
JSObject* global_proxy();
void set_global_proxy(JSObject* global);
// Get the JSGlobalObject object.
JSGlobalObject* global_object();
// Get the script context by traversing the context chain.
Context* script_context();
// Compute the native context.
inline Context* native_context();
inline void set_native_context(Context* context);
// Predicates for context types. IsNativeContext is also defined on Object
// because we frequently have to know if arbitrary objects are natives
// contexts.
inline bool IsNativeContext();
inline bool IsFunctionContext();
inline bool IsCatchContext();
inline bool IsWithContext();
inline bool IsBlockContext();
inline bool IsModuleContext();
inline bool IsScriptContext();
inline bool HasSameSecurityTokenAs(Context* that);
// Initializes global variable bindings in given script context.
void InitializeGlobalSlots();
// 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<Object> ErrorMessageForCodeGenerationFromStrings();
static int ImportedFieldIndexForName(Handle<String> name);
static int IntrinsicIndexForName(Handle<String> name);
static bool IsJSBuiltin(Handle<Context> native_context,
Handle<JSFunction> function);
#define NATIVE_CONTEXT_FIELD_ACCESSORS(index, type, name) \
inline void set_##name(type* value); \
inline bool is_##name(type* value); \
inline type* name();
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 int FunctionMapIndex(LanguageMode language_mode, FunctionKind kind) {
if (IsGeneratorFunction(kind)) {
return is_strong(language_mode) ? STRONG_GENERATOR_FUNCTION_MAP_INDEX :
is_strict(language_mode) ? STRICT_GENERATOR_FUNCTION_MAP_INDEX
: SLOPPY_GENERATOR_FUNCTION_MAP_INDEX;
}
if (IsClassConstructor(kind)) {
// Use strict function map (no own "caller" / "arguments")
return is_strong(language_mode) ? STRONG_CONSTRUCTOR_MAP_INDEX
: STRICT_FUNCTION_MAP_INDEX;
}
if (IsArrowFunction(kind) || IsConciseMethod(kind) ||
IsAccessorFunction(kind)) {
return is_strong(language_mode)
? STRONG_FUNCTION_MAP_INDEX
: STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX;
}
return is_strong(language_mode) ? STRONG_FUNCTION_MAP_INDEX :
is_strict(language_mode) ? STRICT_FUNCTION_MAP_INDEX
: SLOPPY_FUNCTION_MAP_INDEX;
}
static int ArrayMapIndex(ElementsKind elements_kind,
Strength strength = Strength::WEAK) {
DCHECK(IsFastElementsKind(elements_kind));
return elements_kind + (is_strong(strength) ? FIRST_JS_ARRAY_STRONG_MAP_SLOT
: FIRST_JS_ARRAY_MAP_SLOT);
}
static const int kSize = kHeaderSize + NATIVE_CONTEXT_SLOTS * kPointerSize;
static const int kNotFound = -1;
// GC support.
typedef FixedBodyDescriptor<
kHeaderSize, kSize, kSize> ScavengeBodyDescriptor;
typedef FixedBodyDescriptor<
kHeaderSize,
kHeaderSize + FIRST_WEAK_SLOT * kPointerSize,
kSize> MarkCompactBodyDescriptor;
private:
#ifdef DEBUG
// Bootstrapping-aware type checks.
static bool IsBootstrappingOrNativeContext(Isolate* isolate, Object* object);
static bool IsBootstrappingOrValidParentContext(Object* object, Context* kid);
#endif
STATIC_ASSERT(kHeaderSize == Internals::kContextHeaderSize);
STATIC_ASSERT(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex);
};
} // namespace internal
} // namespace v8
#endif // V8_CONTEXTS_H_