0ct0pu5/ladybird
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions 2
ladybird/Userland/Libraries/LibJS/Runtime/VM.cpp
Andreas Kling 41a072bded LibJS: Fast non-local variable access :^) 
This patch introduces the "environment coordinate" concept, which
encodes the distance from a variable access to the binding it ends up
resolving to.

EnvironmentCoordinate has two fields:

    - hops:  The number of hops up the lexical environment chain we have
             to make before getting to the resolved binding.

    - index: The index of the resolved binding within its declarative
             environment record.

Whenever a variable lookup resolves somewhere inside a declarative
environment, we now cache the coordinates and reuse them in subsequent
lookups. This is achieved via a coordinate cache in JS::Identifier.

Note that non-strict direct eval() breaks this optimization and so it
will not be performed if the resolved environment has been permanently
screwed by eval().

This makes variable access *significantly* faster. :^)
2021-10-07 11:53:18 +02:00

836 lines
34 KiB
C++
Raw Blame History

/*
* Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2020-2021, Linus Groh <linusg@serenityos.org>
* Copyright (c) 2021, David Tuin <davidot@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Debug.h>
#include <AK/ScopeGuard.h>
#include <AK/StringBuilder.h>
#include <LibJS/Interpreter.h>
#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/Array.h>
#include <LibJS/Runtime/BoundFunction.h>
#include <LibJS/Runtime/ECMAScriptFunctionObject.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/FinalizationRegistry.h>
#include <LibJS/Runtime/FunctionEnvironment.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/IteratorOperations.h>
#include <LibJS/Runtime/NativeFunction.h>
#include <LibJS/Runtime/PromiseReaction.h>
#include <LibJS/Runtime/Reference.h>
#include <LibJS/Runtime/Symbol.h>
#include <LibJS/Runtime/TemporaryClearException.h>
#include <LibJS/Runtime/VM.h>
namespace JS {
NonnullRefPtr<VM> VM::create(OwnPtr<CustomData> custom_data)
{
return adopt_ref(*new VM(move(custom_data)));
}
VM::VM(OwnPtr<CustomData> custom_data)
: m_heap(*this)
, m_custom_data(move(custom_data))
{
m_empty_string = m_heap.allocate_without_global_object<PrimitiveString>(String::empty());
for (size_t i = 0; i < 128; ++i) {
m_single_ascii_character_strings[i] = m_heap.allocate_without_global_object<PrimitiveString>(String::formatted("{:c}", i));
}
#define __JS_ENUMERATE(SymbolName, snake_name) \
m_well_known_symbol_##snake_name = js_symbol(*this, "Symbol." #SymbolName, false);
JS_ENUMERATE_WELL_KNOWN_SYMBOLS
#undef __JS_ENUMERATE
}
VM::~VM()
{
}
Interpreter& VM::interpreter()
{
VERIFY(!m_interpreters.is_empty());
return *m_interpreters.last();
}
Interpreter* VM::interpreter_if_exists()
{
if (m_interpreters.is_empty())
return nullptr;
return m_interpreters.last();
}
void VM::push_interpreter(Interpreter& interpreter)
{
m_interpreters.append(&interpreter);
}
void VM::pop_interpreter(Interpreter& interpreter)
{
VERIFY(!m_interpreters.is_empty());
auto* popped_interpreter = m_interpreters.take_last();
VERIFY(popped_interpreter == &interpreter);
}
VM::InterpreterExecutionScope::InterpreterExecutionScope(Interpreter& interpreter)
: m_interpreter(interpreter)
{
m_interpreter.vm().push_interpreter(m_interpreter);
}
VM::InterpreterExecutionScope::~InterpreterExecutionScope()
{
m_interpreter.vm().pop_interpreter(m_interpreter);
}
void VM::gather_roots(HashTable<Cell*>& roots)
{
roots.set(m_empty_string);
for (auto* string : m_single_ascii_character_strings)
roots.set(string);
roots.set(m_exception);
if (m_last_value.is_cell())
roots.set(&m_last_value.as_cell());
auto gather_roots_from_execution_context_stack = [&roots](Vector<ExecutionContext*> const& stack) {
for (auto& execution_context : stack) {
if (execution_context->this_value.is_cell())
roots.set(&execution_context->this_value.as_cell());
for (auto& argument : execution_context->arguments) {
if (argument.is_cell())
roots.set(&argument.as_cell());
}
roots.set(execution_context->lexical_environment);
roots.set(execution_context->variable_environment);
}
};
gather_roots_from_execution_context_stack(m_execution_context_stack);
for (auto& saved_stack : m_saved_execution_context_stacks)
gather_roots_from_execution_context_stack(saved_stack);
#define __JS_ENUMERATE(SymbolName, snake_name) \
roots.set(well_known_symbol_##snake_name());
JS_ENUMERATE_WELL_KNOWN_SYMBOLS
#undef __JS_ENUMERATE
for (auto& symbol : m_global_symbol_map)
roots.set(symbol.value);
for (auto* job : m_promise_jobs)
roots.set(job);
for (auto* finalization_registry : m_finalization_registry_cleanup_jobs)
roots.set(finalization_registry);
}
Symbol* VM::get_global_symbol(const String& description)
{
auto result = m_global_symbol_map.get(description);
if (result.has_value())
return result.value();
auto new_global_symbol = js_symbol(*this, description, true);
m_global_symbol_map.set(description, new_global_symbol);
return new_global_symbol;
}
ThrowCompletionOr<Value> VM::named_evaluation_if_anonymous_function(GlobalObject& global_object, ASTNode const& expression, FlyString const& name)
{
// 8.3.3 Static Semantics: IsAnonymousFunctionDefinition ( expr ), https://tc39.es/ecma262/#sec-isanonymousfunctiondefinition
// And 8.3.5 Runtime Semantics: NamedEvaluation, https://tc39.es/ecma262/#sec-runtime-semantics-namedevaluation
if (is<FunctionExpression>(expression)) {
auto& function = static_cast<FunctionExpression const&>(expression);
if (!function.has_name()) {
return function.instantiate_ordinary_function_expression(interpreter(), global_object, name);
}
} else if (is<ClassExpression>(expression)) {
auto& class_expression = static_cast<ClassExpression const&>(expression);
if (!class_expression.has_name()) {
return TRY(class_expression.class_definition_evaluation(interpreter(), global_object, {}, name));
}
}
auto value = expression.execute(interpreter(), global_object);
if (auto* thrown_exception = exception())
return JS::throw_completion(thrown_exception->value());
return value;
}
// 13.15.5.2 Runtime Semantics: DestructuringAssignmentEvaluation, https://tc39.es/ecma262/#sec-runtime-semantics-destructuringassignmentevaluation
ThrowCompletionOr<void> VM::destructuring_assignment_evaluation(NonnullRefPtr<BindingPattern> const& target, Value value, GlobalObject& global_object)
{
// Note: DestructuringAssignmentEvaluation is just like BindingInitialization without an environment
// And it allows member expressions. We thus trust the parser to disallow member expressions
// in any non assignment binding and just call BindingInitialization with a nullptr environment
return binding_initialization(target, value, nullptr, global_object);
}
// 8.5.2 Runtime Semantics: BindingInitialization, https://tc39.es/ecma262/#sec-runtime-semantics-bindinginitialization
ThrowCompletionOr<void> VM::binding_initialization(FlyString const& target, Value value, Environment* environment, GlobalObject& global_object)
{
if (environment) {
environment->initialize_binding(global_object, target, value);
return {};
}
auto reference = resolve_binding(target);
reference.put_value(global_object, value);
if (auto* thrown_exception = exception())
return JS::throw_completion(thrown_exception->value());
return {};
}
// 8.5.2 Runtime Semantics: BindingInitialization, https://tc39.es/ecma262/#sec-runtime-semantics-bindinginitialization
ThrowCompletionOr<void> VM::binding_initialization(NonnullRefPtr<BindingPattern> const& target, Value value, Environment* environment, GlobalObject& global_object)
{
if (target->kind == BindingPattern::Kind::Object) {
TRY(require_object_coercible(global_object, value));
TRY(property_binding_initialization(*target, value, environment, global_object));
return {};
} else {
auto* iterator = get_iterator(global_object, value);
if (!iterator) {
VERIFY(exception());
return JS::throw_completion(exception()->value());
}
auto iterator_done = false;
auto result = iterator_binding_initialization(*target, iterator, iterator_done, environment, global_object);
if (!iterator_done) {
// FIXME: Iterator close should take result and potentially return that. This logic should achieve the same until that is possible.
iterator_close(*iterator);
if (auto* thrown_exception = exception())
return JS::throw_completion(thrown_exception->value());
}
return result;
}
}
// 13.15.5.3 Runtime Semantics: PropertyDestructuringAssignmentEvaluation, https://tc39.es/ecma262/#sec-runtime-semantics-propertydestructuringassignmentevaluation
// 14.3.3.1 Runtime Semantics: PropertyBindingInitialization, https://tc39.es/ecma262/#sec-destructuring-binding-patterns-runtime-semantics-propertybindinginitialization
ThrowCompletionOr<void> VM::property_binding_initialization(BindingPattern const& binding, Value value, Environment* environment, GlobalObject& global_object)
{
auto* object = value.to_object(global_object);
if (!object) {
VERIFY(exception());
return JS::throw_completion(exception()->value());
}
HashTable<PropertyName, PropertyNameTraits> seen_names;
for (auto& property : binding.entries) {
VERIFY(!property.is_elision());
if (property.is_rest) {
Reference assignment_target;
if (auto identifier_ptr = property.name.get_pointer<NonnullRefPtr<Identifier>>()) {
assignment_target = resolve_binding((*identifier_ptr)->string(), environment);
} else if (auto member_ptr = property.alias.get_pointer<NonnullRefPtr<MemberExpression>>()) {
assignment_target = (*member_ptr)->to_reference(interpreter(), global_object);
} else {
VERIFY_NOT_REACHED();
}
if (auto* thrown_exception = exception())
return JS::throw_completion(thrown_exception->value());
auto* rest_object = Object::create(global_object, global_object.object_prototype());
VERIFY(rest_object);
TRY(rest_object->copy_data_properties(object, seen_names, global_object));
if (!environment)
assignment_target.put_value(global_object, rest_object);
else
assignment_target.initialize_referenced_binding(global_object, rest_object);
break;
}
PropertyName name;
property.name.visit(
[&](Empty) { VERIFY_NOT_REACHED(); },
[&](NonnullRefPtr<Identifier> const& identifier) {
name = identifier->string();
},
[&](NonnullRefPtr<Expression> const& expression) {
auto result = expression->execute(interpreter(), global_object);
if (exception())
return;
name = result.to_property_key(global_object);
});
if (auto* thrown_exception = exception())
return JS::throw_completion(thrown_exception->value());
seen_names.set(name);
if (property.name.has<NonnullRefPtr<Identifier>>() && property.alias.has<Empty>()) {
// FIXME: this branch and not taking this have a lot in common we might want to unify it more (like it was before).
auto& identifier = *property.name.get<NonnullRefPtr<Identifier>>();
auto reference = resolve_binding(identifier.string(), environment);
if (auto* thrown_exception = exception())
return JS::throw_completion(thrown_exception->value());
auto value_to_assign = TRY(object->get(name));
if (property.initializer && value_to_assign.is_undefined()) {
value_to_assign = TRY(named_evaluation_if_anonymous_function(global_object, *property.initializer, identifier.string()));
}
if (!environment)
reference.put_value(global_object, value_to_assign);
else
reference.initialize_referenced_binding(global_object, value_to_assign);
continue;
}
Optional<Reference> reference_to_assign_to;
property.alias.visit(
[&](Empty) {},
[&](NonnullRefPtr<Identifier> const& identifier) {
reference_to_assign_to = resolve_binding(identifier->string(), environment);
},
[&](NonnullRefPtr<BindingPattern> const&) {},
[&](NonnullRefPtr<MemberExpression> const& member_expression) {
reference_to_assign_to = member_expression->to_reference(interpreter(), global_object);
});
if (auto* thrown_exception = exception())
return JS::throw_completion(thrown_exception->value());
auto value_to_assign = TRY(object->get(name));
if (property.initializer && value_to_assign.is_undefined()) {
if (auto* identifier_ptr = property.alias.get_pointer<NonnullRefPtr<Identifier>>())
value_to_assign = TRY(named_evaluation_if_anonymous_function(global_object, *property.initializer, (*identifier_ptr)->string()));
else
value_to_assign = property.initializer->execute(interpreter(), global_object);
if (auto* thrown_exception = exception())
return JS::throw_completion(thrown_exception->value());
}
if (auto* binding_ptr = property.alias.get_pointer<NonnullRefPtr<BindingPattern>>()) {
TRY(binding_initialization(*binding_ptr, value_to_assign, environment, global_object));
} else {
VERIFY(reference_to_assign_to.has_value());
if (!environment)
reference_to_assign_to->put_value(global_object, value_to_assign);
else
reference_to_assign_to->initialize_referenced_binding(global_object, value_to_assign);
if (auto* thrown_exception = exception())
return JS::throw_completion(thrown_exception->value());
}
}
return {};
}
// 13.15.5.5 Runtime Semantics: IteratorDestructuringAssignmentEvaluation, https://tc39.es/ecma262/#sec-runtime-semantics-iteratordestructuringassignmentevaluation
// 8.5.3 Runtime Semantics: IteratorBindingInitialization, https://tc39.es/ecma262/#sec-runtime-semantics-iteratorbindinginitialization
ThrowCompletionOr<void> VM::iterator_binding_initialization(BindingPattern const& binding, Object* iterator, bool& iterator_done, Environment* environment, GlobalObject& global_object)
{
// FIXME: this method is nearly identical to destructuring assignment!
for (size_t i = 0; i < binding.entries.size(); i++) {
auto& entry = binding.entries[i];
Value value;
Optional<Reference> assignment_target;
entry.alias.visit(
[&](Empty) {},
[&](NonnullRefPtr<Identifier> const& identifier) {
assignment_target = resolve_binding(identifier->string(), environment);
},
[&](NonnullRefPtr<BindingPattern> const&) {},
[&](NonnullRefPtr<MemberExpression> const& member_expression) {
assignment_target = member_expression->to_reference(interpreter(), global_object);
});
if (auto* thrown_exception = exception())
return JS::throw_completion(thrown_exception->value());
if (entry.is_rest) {
VERIFY(i == binding.entries.size() - 1);
auto* array = Array::create(global_object, 0);
while (!iterator_done) {
auto next_object = iterator_next(*iterator);
if (!next_object) {
iterator_done = true;
VERIFY(exception());
return JS::throw_completion(exception()->value());
}
auto done_property = TRY(next_object->get(names.done));
if (done_property.to_boolean()) {
iterator_done = true;
break;
}
auto next_value = TRY(next_object->get(names.value));
array->indexed_properties().append(next_value);
}
value = array;
} else if (!iterator_done) {
auto next_object = iterator_next(*iterator);
if (!next_object) {
iterator_done = true;
VERIFY(exception());
return JS::throw_completion(exception()->value());
}
auto done_property = TRY(next_object->get(names.done));
if (done_property.to_boolean()) {
iterator_done = true;
value = js_undefined();
} else {
auto value_or_error = next_object->get(names.value);
if (value_or_error.is_throw_completion()) {
iterator_done = true;
return JS::throw_completion(value_or_error.release_error().value());
}
value = value_or_error.release_value();
}
} else {
value = js_undefined();
}
if (value.is_undefined() && entry.initializer) {
VERIFY(!entry.is_rest);
if (auto* identifier_ptr = entry.alias.get_pointer<NonnullRefPtr<Identifier>>())
value = TRY(named_evaluation_if_anonymous_function(global_object, *entry.initializer, (*identifier_ptr)->string()));
else
value = entry.initializer->execute(interpreter(), global_object);
if (auto* thrown_exception = exception())
return JS::throw_completion(thrown_exception->value());
}
if (auto* binding_ptr = entry.alias.get_pointer<NonnullRefPtr<BindingPattern>>()) {
TRY(binding_initialization(*binding_ptr, value, environment, global_object));
} else if (!entry.alias.has<Empty>()) {
VERIFY(assignment_target.has_value());
if (!environment)
assignment_target->put_value(global_object, value);
else
assignment_target->initialize_referenced_binding(global_object, value);
if (auto* thrown_exception = exception())
return JS::throw_completion(thrown_exception->value());
}
}
return {};
}
// 9.1.2.1 GetIdentifierReference ( env, name, strict ), https://tc39.es/ecma262/#sec-getidentifierreference
Reference VM::get_identifier_reference(Environment* environment, FlyString name, bool strict, size_t hops)
{
// 1. If env is the value null, then
if (!environment) {
// a. Return the Reference Record { [[Base]]: unresolvable, [[ReferencedName]]: name, [[Strict]]: strict, [[ThisValue]]: empty }.
return Reference { Reference::BaseType::Unresolvable, move(name), strict };
}
Optional<size_t> index;
auto exists = environment->has_binding(name, &index);
if (exception())
return {};
Optional<EnvironmentCoordinate> environment_coordinate;
if (index.has_value())
environment_coordinate = EnvironmentCoordinate { .hops = hops, .index = index.value() };
if (exists)
return Reference { *environment, move(name), strict, environment_coordinate };
else
return get_identifier_reference(environment->outer_environment(), move(name), strict, hops + 1);
}
// 9.4.2 ResolveBinding ( name [ , env ] ), https://tc39.es/ecma262/#sec-resolvebinding
Reference VM::resolve_binding(FlyString const& name, Environment* environment)
{
// 1. If env is not present or if env is undefined, then
if (!environment) {
// a. Set env to the running execution context's LexicalEnvironment.
environment = running_execution_context().lexical_environment;
}
// 2. Assert: env is an Environment Record.
VERIFY(environment);
// 3. If the code matching the syntactic production that is being evaluated is contained in strict mode code, let strict be true; else let strict be false.
bool strict = in_strict_mode();
// 4. Return ? GetIdentifierReference(env, name, strict).
return get_identifier_reference(environment, name, strict);
}
static void append_bound_and_passed_arguments(MarkedValueList& arguments, Vector<Value> bound_arguments, Optional<MarkedValueList> passed_arguments)
{
arguments.ensure_capacity(bound_arguments.size());
arguments.extend(move(bound_arguments));
if (passed_arguments.has_value()) {
auto arguments_list = move(passed_arguments.release_value().values());
arguments.grow_capacity(arguments_list.size());
arguments.extend(move(arguments_list));
}
}
// 7.3.32 InitializeInstanceElements ( O, constructor ), https://tc39.es/ecma262/#sec-initializeinstanceelements
void VM::initialize_instance_elements(Object& object, ECMAScriptFunctionObject& constructor)
{
for (auto& field : constructor.fields()) {
field.define_field(*this, object);
if (exception())
return;
}
}
// FIXME: This function should not exist as-is, most of it should be moved to the individual
// [[Construct]] implementations so that this becomes the Construct() AO (3 steps).
Value VM::construct(FunctionObject& function, FunctionObject& new_target, Optional<MarkedValueList> arguments)
{
auto& global_object = function.global_object();
Value this_argument;
if (!is<ECMAScriptFunctionObject>(function) || static_cast<ECMAScriptFunctionObject&>(function).constructor_kind() == ECMAScriptFunctionObject::ConstructorKind::Base)
this_argument = TRY_OR_DISCARD(ordinary_create_from_constructor<Object>(global_object, new_target, &GlobalObject::object_prototype));
// FIXME: prepare_for_ordinary_call() is not supposed to receive a BoundFunction, ProxyObject, etc. - ever.
// This needs to be moved to NativeFunction/ECMAScriptFunctionObject's construct() (10.2.2 [[Construct]])
ExecutionContext callee_context(heap());
prepare_for_ordinary_call(function, callee_context, &new_target);
if (exception())
return {};
ArmedScopeGuard pop_guard = [&] {
pop_execution_context();
};
if (auto* interpreter = interpreter_if_exists())
callee_context.current_node = interpreter->current_node();
if (is<BoundFunction>(function)) {
auto& bound_function = static_cast<BoundFunction&>(function);
append_bound_and_passed_arguments(callee_context.arguments, bound_function.bound_arguments(), move(arguments));
} else {
append_bound_and_passed_arguments(callee_context.arguments, {}, move(arguments));
}
if (auto* environment = callee_context.lexical_environment) {
auto& function_environment = verify_cast<FunctionEnvironment>(*environment);
function_environment.set_new_target(&new_target);
if (!this_argument.is_empty() && function_environment.this_binding_status() != FunctionEnvironment::ThisBindingStatus::Lexical) {
function_environment.bind_this_value(global_object, this_argument);
if (exception())
return {};
}
}
// If we are a Derived constructor, |this| has not been constructed before super is called.
callee_context.this_value = this_argument;
if (is<ECMAScriptFunctionObject>(function) && static_cast<ECMAScriptFunctionObject&>(function).constructor_kind() == ECMAScriptFunctionObject::ConstructorKind::Base) {
VERIFY(this_argument.is_object());
initialize_instance_elements(this_argument.as_object(), static_cast<ECMAScriptFunctionObject&>(function));
if (exception())
return {};
}
auto* constructor_environment = callee_context.lexical_environment;
auto result = function.construct(new_target);
VERIFY(constructor_environment);
pop_execution_context();
pop_guard.disarm();
// If we are constructing an instance of a derived class,
// set the prototype on objects created by constructors that return an object (i.e. NativeFunction subclasses).
if ((!is<ECMAScriptFunctionObject>(function) || static_cast<ECMAScriptFunctionObject&>(function).constructor_kind() == ECMAScriptFunctionObject::ConstructorKind::Base)
&& is<ECMAScriptFunctionObject>(new_target) && static_cast<ECMAScriptFunctionObject&>(new_target).constructor_kind() == ECMAScriptFunctionObject::ConstructorKind::Derived
&& result.is_object()) {
verify_cast<FunctionEnvironment>(constructor_environment)->replace_this_binding(result);
auto prototype = TRY_OR_DISCARD(new_target.get(names.prototype));
if (prototype.is_object())
TRY_OR_DISCARD(result.as_object().internal_set_prototype_of(&prototype.as_object()));
return result;
}
if (exception())
return {};
if (result.is_object())
return result;
if (is<ECMAScriptFunctionObject>(function) && static_cast<ECMAScriptFunctionObject&>(function).constructor_kind() == ECMAScriptFunctionObject::ConstructorKind::Base)
return this_argument;
if (!result.is_empty() && !result.is_undefined()) {
throw_exception<TypeError>(global_object, ErrorType::DerivedConstructorReturningInvalidValue);
return {};
}
VERIFY(constructor_environment);
return constructor_environment->get_this_binding(global_object);
}
void VM::throw_exception(Exception& exception)
{
set_exception(exception);
unwind(ScopeType::Try);
}
// 9.4.4 ResolveThisBinding ( ), https://tc39.es/ecma262/#sec-resolvethisbinding
Value VM::resolve_this_binding(GlobalObject& global_object)
{
auto& environment = get_this_environment(*this);
return environment.get_this_binding(global_object);
}
String VM::join_arguments(size_t start_index) const
{
StringBuilder joined_arguments;
for (size_t i = start_index; i < argument_count(); ++i) {
joined_arguments.append(argument(i).to_string_without_side_effects().characters());
if (i != argument_count() - 1)
joined_arguments.append(' ');
}
return joined_arguments.build();
}
Value VM::get_new_target()
{
auto& env = get_this_environment(*this);
return verify_cast<FunctionEnvironment>(env).new_target();
}
// 10.2.1.1 PrepareForOrdinaryCall ( F, newTarget ), https://tc39.es/ecma262/#sec-prepareforordinarycall
void VM::prepare_for_ordinary_call(FunctionObject& function, ExecutionContext& callee_context, Object* new_target)
{
// NOTE: This is a LibJS specific hack for NativeFunction to inherit the strictness of its caller.
// FIXME: I feel like we should be able to get rid of this.
if (is<NativeFunction>(function))
callee_context.is_strict_mode = in_strict_mode();
else
callee_context.is_strict_mode = function.is_strict_mode();
// 1. Let callerContext be the running execution context.
// 2. Let calleeContext be a new ECMAScript code execution context.
// NOTE: In the specification, PrepareForOrdinaryCall "returns" a new callee execution context.
// To avoid heap allocations, we put our ExecutionContext objects on the C++ stack instead.
// Whoever calls us should put an ExecutionContext on their stack and pass that as the `callee_context`.
// 3. Set the Function of calleeContext to F.
callee_context.function = &function;
callee_context.function_name = function.name();
// 4. Let calleeRealm be F.[[Realm]].
auto* callee_realm = function.realm();
// FIXME: See FIXME in VM::call_internal() / VM::construct().
if (!callee_realm)
callee_realm = current_realm();
VERIFY(callee_realm);
// 5. Set the Realm of calleeContext to calleeRealm.
callee_context.realm = callee_realm;
// 6. Set the ScriptOrModule of calleeContext to F.[[ScriptOrModule]].
// FIXME: Our execution context struct currently does not track this item.
// 7. Let localEnv be NewFunctionEnvironment(F, newTarget).
auto* local_environment = function.new_function_environment(new_target);
// 8. Set the LexicalEnvironment of calleeContext to localEnv.
callee_context.lexical_environment = local_environment;
// 9. Set the VariableEnvironment of calleeContext to localEnv.
callee_context.variable_environment = local_environment;
// 10. Set the PrivateEnvironment of calleeContext to F.[[PrivateEnvironment]].
// FIXME: We currently don't support private environments.
// 11. If callerContext is not already suspended, suspend callerContext.
// FIXME: We don't have this concept yet.
// 12. Push calleeContext onto the execution context stack; calleeContext is now the running execution context.
push_execution_context(callee_context, function.global_object());
// 13. NOTE: Any exception objects produced after this point are associated with calleeRealm.
// 14. Return calleeContext. (See NOTE above about how contexts are allocated on the C++ stack.)
}
// 10.2.1.2 OrdinaryCallBindThis ( F, calleeContext, thisArgument ), https://tc39.es/ecma262/#sec-ordinarycallbindthis
void VM::ordinary_call_bind_this(FunctionObject& function, ExecutionContext& callee_context, Value this_argument)
{
auto* callee_realm = function.realm();
auto* local_environment = callee_context.lexical_environment;
auto& function_environment = verify_cast<FunctionEnvironment>(*local_environment);
// This almost as the spec describes it however we sometimes don't have callee_realm when dealing
// with proxies and arrow functions however this does seemingly achieve spec like behavior.
if (!callee_realm || (is<ECMAScriptFunctionObject>(function) && static_cast<ECMAScriptFunctionObject&>(function).this_mode() == ECMAScriptFunctionObject::ThisMode::Lexical)) {
return;
}
Value this_value;
if (function.is_strict_mode()) {
this_value = this_argument;
} else if (this_argument.is_nullish()) {
auto& global_environment = callee_realm->global_environment();
this_value = &global_environment.global_this_value();
} else {
this_value = this_argument.to_object(function.global_object());
}
function_environment.bind_this_value(function.global_object(), this_value);
callee_context.this_value = this_value;
}
ThrowCompletionOr<Value> VM::call_internal(FunctionObject& function, Value this_value, Optional<MarkedValueList> arguments)
{
VERIFY(!exception());
VERIFY(!this_value.is_empty());
if (is<BoundFunction>(function)) {
auto& bound_function = static_cast<BoundFunction&>(function);
MarkedValueList with_bound_arguments { heap() };
append_bound_and_passed_arguments(with_bound_arguments, bound_function.bound_arguments(), move(arguments));
return call_internal(bound_function.bound_target_function(), bound_function.bound_this(), move(with_bound_arguments));
}
// FIXME: prepare_for_ordinary_call() is not supposed to receive a BoundFunction, ProxyObject, etc. - ever.
// This needs to be moved to NativeFunction/ECMAScriptFunctionObject's construct() (10.2.2 [[Construct]])
ExecutionContext callee_context(heap());
prepare_for_ordinary_call(function, callee_context, nullptr);
if (auto* exception = this->exception())
return JS::throw_completion(exception->value());
ScopeGuard pop_guard = [&] {
pop_execution_context();
};
if (auto* interpreter = interpreter_if_exists())
callee_context.current_node = interpreter->current_node();
callee_context.this_value = this_value;
append_bound_and_passed_arguments(callee_context.arguments, {}, move(arguments));
ordinary_call_bind_this(function, callee_context, this_value);
if (auto* exception = this->exception())
return JS::throw_completion(exception->value());
auto result = function.call();
if (auto* exception = this->exception())
return JS::throw_completion(exception->value());
return result;
}
bool VM::in_strict_mode() const
{
if (execution_context_stack().is_empty())
return false;
return running_execution_context().is_strict_mode;
}
void VM::run_queued_promise_jobs()
{
dbgln_if(PROMISE_DEBUG, "Running queued promise jobs");
// Temporarily get rid of the exception, if any - job functions must be called
// either way, and that can't happen if we already have an exception stored.
TemporaryClearException clear_exception(*this);
while (!m_promise_jobs.is_empty()) {
auto* job = m_promise_jobs.take_first();
dbgln_if(PROMISE_DEBUG, "Calling promise job function @ {}", job);
[[maybe_unused]] auto result = call(*job, js_undefined());
}
// Ensure no job has created a new exception, they must clean up after themselves.
VERIFY(!m_exception);
}
// 9.5.4 HostEnqueuePromiseJob ( job, realm ), https://tc39.es/ecma262/#sec-hostenqueuepromisejob
void VM::enqueue_promise_job(NativeFunction& job)
{
m_promise_jobs.append(&job);
}
void VM::run_queued_finalization_registry_cleanup_jobs()
{
while (!m_finalization_registry_cleanup_jobs.is_empty()) {
auto* registry = m_finalization_registry_cleanup_jobs.take_first();
registry->cleanup();
}
}
// 9.10.4.1 HostEnqueueFinalizationRegistryCleanupJob ( finalizationRegistry ), https://tc39.es/ecma262/#sec-host-cleanup-finalization-registry
void VM::enqueue_finalization_registry_cleanup_job(FinalizationRegistry& registry)
{
m_finalization_registry_cleanup_jobs.append(&registry);
}
// 27.2.1.9 HostPromiseRejectionTracker ( promise, operation ), https://tc39.es/ecma262/#sec-host-promise-rejection-tracker
void VM::promise_rejection_tracker(const Promise& promise, Promise::RejectionOperation operation) const
{
switch (operation) {
case Promise::RejectionOperation::Reject:
// A promise was rejected without any handlers
if (on_promise_unhandled_rejection)
on_promise_unhandled_rejection(promise);
break;
case Promise::RejectionOperation::Handle:
// A handler was added to an already rejected promise
if (on_promise_rejection_handled)
on_promise_rejection_handled(promise);
break;
default:
VERIFY_NOT_REACHED();
}
}
void VM::dump_backtrace() const
{
for (ssize_t i = m_execution_context_stack.size() - 1; i >= 0; --i) {
auto& frame = m_execution_context_stack[i];
if (frame->current_node) {
auto& source_range = frame->current_node->source_range();
dbgln("-> {} @ {}:{},{}", frame->function_name, source_range.filename, source_range.start.line, source_range.start.column);
} else {
dbgln("-> {}", frame->function_name);
}
}
}
VM::CustomData::~CustomData()
{
}
void VM::save_execution_context_stack()
{
m_saved_execution_context_stacks.append(move(m_execution_context_stack));
}
void VM::restore_execution_context_stack()
{
m_execution_context_stack = m_saved_execution_context_stacks.take_last();
}
}
Reference in a new issue View git blame Copy permalink