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v8/src/contexts.h
Erik Arvidsson b67b3c5401 Accessor functions should have no prototype property 
This also removes some convenience functions that were not used.

BUG=v8:3700
LOG=N
R=adamk@chromium.org, adamk

Review URL: https://codereview.chromium.org/883073008

Cr-Commit-Position: refs/heads/master@{#26472}
2015-02-05 23:34:28 +00:00

616 lines
27 KiB
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// 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,
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(TO_LENGTH_FUN_INDEX, JSFunction, to_length_fun) \
V(GLOBAL_EVAL_FUN_INDEX, JSFunction, global_eval_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(BOUND_FUNCTION_MAP_INDEX, Map, bound_function_map) \
V(REGEXP_RESULT_MAP_INDEX, Map, regexp_result_map) \
V(SLOPPY_ARGUMENTS_MAP_INDEX, Map, sloppy_arguments_map) \
V(ALIASED_ARGUMENTS_MAP_INDEX, Map, aliased_arguments_map) \
V(STRICT_ARGUMENTS_MAP_INDEX, Map, strict_arguments_map) \
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, FixedArray, function_cache) \
V(JSFUNCTION_RESULT_CACHES_INDEX, FixedArray, jsfunction_result_caches) \
V(NORMALIZED_MAP_CACHE_INDEX, Object, 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) \
V(ARRAY_VALUES_ITERATOR_INDEX, JSFunction, array_values_iterator) \
V(SCRIPT_CONTEXT_TABLE_INDEX, ScriptContextTable, script_context_table)
// 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 ScriptContextTable* cast(Object* context) {
DCHECK(context->IsScriptContextTable());
return reinterpret_cast<ScriptContextTable*>(context);
}
struct LookupResult {
int context_index;
int slot_index;
VariableMode mode;
InitializationFlag init_flag;
MaybeAssignedFlag maybe_assigned_flag;
};
int used() const { return Smi::cast(get(kUsedSlot))->value(); }
void set_used(int used) { set(kUsedSlot, Smi::FromInt(used)); }
static Handle<Context> GetContext(Handle<ScriptContextTable> table, int i) {
DCHECK(i < table->used());
return Handle<Context>::cast(FixedArray::get(table, i + 1));
}
// 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 kFirstContextOffset =
FixedArray::kHeaderSize + (kUsedSlot + 1) * 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 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 ScriptContext rather than a FunctionContext.
// Script contexts from all top-level scripts are gathered in
// ScriptContextTable.
class Context: public FixedArray {
public:
// Conversions.
static Context* cast(Object* context) {
DCHECK(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,
SLOPPY_ARGUMENTS_MAP_INDEX,
ALIASED_ARGUMENTS_MAP_INDEX,
STRICT_ARGUMENTS_MAP_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,
BOUND_FUNCTION_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,
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,
ARRAY_VALUES_ITERATOR_INDEX,
SCRIPT_CONTEXT_TABLE_INDEX,
MAP_CACHE_INDEX,
TO_LENGTH_FUN_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.
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();
DCHECK(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);
DCHECK(IsBootstrappingOrGlobalObject(this->GetIsolate(), 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 script context by traversing the context chain.
Context* script_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 IsScriptContext() {
Map* map = this->map();
return map == map->GetHeap()->script_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<Object> ErrorMessageForCodeGenerationFromStrings();
#define NATIVE_CONTEXT_FIELD_ACCESSORS(index, type, name) \
void set_##name(type* value) { \
DCHECK(IsNativeContext()); \
set(index, value); \
} \
bool is_##name(type* value) { \
DCHECK(IsNativeContext()); \
return type::cast(get(index)) == value; \
} \
type* name() { \
DCHECK(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 int FunctionMapIndex(LanguageMode language_mode, FunctionKind kind) {
if (IsGeneratorFunction(kind)) {
return is_strict(language_mode) ? STRICT_GENERATOR_FUNCTION_MAP_INDEX
: SLOPPY_GENERATOR_FUNCTION_MAP_INDEX;
}
if (IsArrowFunction(kind) || IsConciseMethod(kind) ||
IsAccessorFunction(kind)) {
return is_strict(language_mode)
? STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX
: SLOPPY_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX;
}
return is_strict(language_mode) ? STRICT_FUNCTION_MAP_INDEX
: SLOPPY_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_
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