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LibJS: Ensure get_new_target() never returns an empty value

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Also add spec comments and remove a redundant exception check while
we're here :^)
This commit is contained in:
Linus Groh 2021-12-28 23:50:23 +01:00
parent 8d70a50aed
commit 451149df0b
4 changed files with 17 additions and 12 deletions
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4
Userland/Libraries/LibJS/AST.cpp
View file

@ -347,8 +347,6 @@ Value SuperCall::execute(Interpreter& interpreter, GlobalObject& global_object)
// 1. Let newTarget be GetNewTarget().
auto new_target = vm.get_new_target();
if (vm.exception())
return {};
// 2. Assert: Type(newTarget) is Object.
VERIFY(new_target.is_function());
@ -2873,7 +2871,7 @@ Value MetaProperty::execute(Interpreter& interpreter, GlobalObject& global_objec
InterpreterNodeScope node_scope { interpreter, *this };
if (m_type == MetaProperty::Type::NewTarget)
return interpreter.vm().get_new_target().value_or(js_undefined());
return interpreter.vm().get_new_target();
if (m_type == MetaProperty::Type::ImportMeta) {
interpreter.vm().throw_exception<InternalError>(global_object, ErrorType::NotImplemented, "'import.meta' in modules");
return {};

2
Userland/Libraries/LibJS/Runtime/FunctionEnvironment.cpp
View file

@ -81,6 +81,8 @@ ThrowCompletionOr<Value> FunctionEnvironment::get_this_binding(GlobalObject& glo
// 9.1.1.3.1 BindThisValue ( V ), https://tc39.es/ecma262/#sec-bindthisvalue
ThrowCompletionOr<Value> FunctionEnvironment::bind_this_value(GlobalObject& global_object, Value this_value)
{
VERIFY(!this_value.is_empty());
// 1. Assert: envRec.[[ThisBindingStatus]] is not lexical.
VERIFY(m_this_binding_status != ThisBindingStatus::Lexical);

18
Userland/Libraries/LibJS/Runtime/FunctionEnvironment.h
View file

@ -25,22 +25,22 @@ public:
explicit FunctionEnvironment(Environment* parent_scope);
virtual ~FunctionEnvironment() override;
// [[ThisValue]]
Value this_value() const { return m_this_value; }
void set_this_value(Value value) { m_this_value = value; }
// [[ThisBindingStatus]]
ThisBindingStatus this_binding_status() const { return m_this_binding_status; }
void set_this_binding_status(ThisBindingStatus status) { m_this_binding_status = status; }
// [[FunctionObject]]
ECMAScriptFunctionObject& function_object() { return *m_function_object; }
ECMAScriptFunctionObject const& function_object() const { return *m_function_object; }
void set_function_object(ECMAScriptFunctionObject& function) { m_function_object = &function; }
// [[NewTarget]]
Value new_target() const { return m_new_target; }
void set_new_target(Value new_target) { m_new_target = new_target; }
void set_new_target(Value new_target)
{
VERIFY(!new_target.is_empty());
m_new_target = new_target;
}
// Abstract operations
ThrowCompletionOr<Value> get_super_base() const;
@ -53,10 +53,10 @@ private:
virtual bool is_function_environment() const override { return true; }
virtual void visit_edges(Visitor&) override;
Value m_this_value;
ThisBindingStatus m_this_binding_status { ThisBindingStatus::Uninitialized };
ECMAScriptFunctionObject* m_function_object { nullptr };
Value m_new_target;
Value m_this_value; // [[ThisValue]]
ThisBindingStatus m_this_binding_status { ThisBindingStatus::Uninitialized }; // [[ThisBindingStatus]]
ECMAScriptFunctionObject* m_function_object { nullptr }; // [[FunctionObject]]
Value m_new_target { js_undefined() }; // [[NewTarget]]
};
template<>

5
Userland/Libraries/LibJS/Runtime/VM.cpp
View file

@ -497,9 +497,14 @@ String VM::join_arguments(size_t start_index) const
return joined_arguments.build();
}
// 9.4.5 GetNewTarget ( ), https://tc39.es/ecma262/#sec-getnewtarget
Value VM::get_new_target()
{
// 1. Let envRec be GetThisEnvironment().
auto& env = get_this_environment(*this);
// 2. Assert: envRec has a [[NewTarget]] field.
// 3. Return envRec.[[NewTarget]].
return verify_cast<FunctionEnvironment>(env).new_target();
}