RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 03:57:43 +00:00
Code Issues Activity Actions

LibJS: More properly implement scoping rules in bytecode codegen

Browse source 
Now we emit CreateVariable and SetVariable with the appropriate
initialization/environment modes, much closer to the spec.
This makes a whole lot of things like let/const variables, function
and variable hoisting and some other things work :^)
This commit is contained in:
Ali Mohammad Pur 2022-02-12 19:48:45 +03:30 • committed by Linus Groh
parent c7e6b65fd2
commit 1bbfaf8627
12 changed files with 503 additions and 38 deletions
Download patch file Download diff file Expand all files Collapse all files

94
Userland/Libraries/LibJS/Bytecode/Op.cpp
View file

@ -260,12 +260,63 @@ ThrowCompletionOr<void> GetVariable::execute_impl(Bytecode::Interpreter& interpr
return {};
}
ThrowCompletionOr<void> CreateEnvironment::execute_impl(Bytecode::Interpreter& interpreter) const
{
auto make_and_swap_envs = [&](auto*& old_environment) {
Environment* environment = new_declarative_environment(*old_environment);
swap(old_environment, environment);
return environment;
};
if (m_mode == EnvironmentMode::Lexical)
interpreter.saved_lexical_environment_stack().append(make_and_swap_envs(interpreter.vm().running_execution_context().lexical_environment));
else if (m_mode == EnvironmentMode::Var)
interpreter.saved_variable_environment_stack().append(make_and_swap_envs(interpreter.vm().running_execution_context().variable_environment));
return {};
}
ThrowCompletionOr<void> CreateVariable::execute_impl(Bytecode::Interpreter& interpreter) const
{
auto& vm = interpreter.vm();
auto const& name = interpreter.current_executable().get_identifier(m_identifier);
if (m_mode == EnvironmentMode::Lexical) {
// Note: This is papering over an issue where "FunctionDeclarationInstantiation" creates these bindings for us.
// Instead of crashing in there, we'll just raise an exception here.
if (TRY(vm.lexical_environment()->has_binding(name)))
return vm.throw_completion<InternalError>(interpreter.global_object(), String::formatted("Lexical environment already has binding '{}'", name));
if (m_is_immutable)
vm.lexical_environment()->create_immutable_binding(interpreter.global_object(), name, vm.in_strict_mode());
else
vm.lexical_environment()->create_mutable_binding(interpreter.global_object(), name, vm.in_strict_mode());
} else {
if (m_is_immutable)
vm.variable_environment()->create_immutable_binding(interpreter.global_object(), name, vm.in_strict_mode());
else
vm.variable_environment()->create_mutable_binding(interpreter.global_object(), name, vm.in_strict_mode());
}
return {};
}
ThrowCompletionOr<void> SetVariable::execute_impl(Bytecode::Interpreter& interpreter) const
{
auto& vm = interpreter.vm();
auto reference = TRY(vm.resolve_binding(interpreter.current_executable().get_identifier(m_identifier)));
TRY(reference.put_value(interpreter.global_object(), interpreter.accumulator()));
auto const& name = interpreter.current_executable().get_identifier(m_identifier);
auto environment = m_mode == EnvironmentMode::Lexical ? vm.running_execution_context().lexical_environment : vm.running_execution_context().variable_environment;
auto reference = TRY(vm.resolve_binding(name, environment));
switch (m_initialization_mode) {
case InitializationMode::Initialize:
TRY(reference.initialize_referenced_binding(interpreter.global_object(), interpreter.accumulator()));
break;
case InitializationMode::Set:
TRY(reference.put_value(interpreter.global_object(), interpreter.accumulator()));
break;
case InitializationMode::InitializeOrSet:
VERIFY(reference.is_environment_reference());
VERIFY(reference.base_environment().is_declarative_environment());
TRY(static_cast<DeclarativeEnvironment&>(reference.base_environment()).initialize_or_set_mutable_binding(interpreter.global_object(), name, interpreter.accumulator()));
break;
}
return {};
}
@ -440,6 +491,15 @@ void FinishUnwind::replace_references_impl(BasicBlock const& from, BasicBlock co
m_next_target = Label { to };
}
ThrowCompletionOr<void> LeaveEnvironment::execute_impl(Bytecode::Interpreter& interpreter) const
{
if (m_mode == EnvironmentMode::Lexical)
interpreter.vm().running_execution_context().lexical_environment = interpreter.saved_lexical_environment_stack().take_last();
if (m_mode == EnvironmentMode::Var)
interpreter.vm().running_execution_context().variable_environment = interpreter.saved_variable_environment_stack().take_last();
return {};
}
ThrowCompletionOr<void> LeaveUnwindContext::execute_impl(Bytecode::Interpreter& interpreter) const
{
interpreter.leave_unwind_context();
@ -628,9 +688,27 @@ String GetVariable::to_string_impl(Bytecode::Executable const& executable) const
return String::formatted("GetVariable {} ({})", m_identifier, executable.identifier_table->get(m_identifier));
}
String CreateEnvironment::to_string_impl(Bytecode::Executable const&) const
{
auto mode_string = m_mode == EnvironmentMode::Lexical
? "Lexical"
: "Variable";
return String::formatted("CreateEnvironment mode:{}", mode_string);
}
String CreateVariable::to_string_impl(Bytecode::Executable const& executable) const
{
auto mode_string = m_mode == EnvironmentMode::Lexical ? "Lexical" : "Variable";
return String::formatted("CreateVariable env:{} immutable:{} {} ({})", mode_string, m_is_immutable, m_identifier, executable.identifier_table->get(m_identifier));
}
String SetVariable::to_string_impl(Bytecode::Executable const& executable) const
{
return String::formatted("SetVariable {} ({})", m_identifier, executable.identifier_table->get(m_identifier));
auto initialization_mode_name = m_initialization_mode == InitializationMode ::Initialize ? "Initialize"
: m_initialization_mode == InitializationMode::Set ? "Set"
: "InitializeOrSet";
auto mode_string = m_mode == EnvironmentMode::Lexical ? "Lexical" : "Variable";
return String::formatted("SetVariable env:{} init:{} {} ({})", mode_string, initialization_mode_name, m_identifier, executable.identifier_table->get(m_identifier));
}
String PutById::to_string_impl(Bytecode::Executable const& executable) const
@ -729,6 +807,14 @@ String FinishUnwind::to_string_impl(const Bytecode::Executable&) const
return String::formatted("FinishUnwind next:{}", m_next_target);
}
String LeaveEnvironment::to_string_impl(Bytecode::Executable const&) const
{
auto mode_string = m_mode == EnvironmentMode::Lexical
? "Lexical"
: "Variable";
return String::formatted("LeaveEnvironment env:{}", mode_string);
}
String LeaveUnwindContext::to_string_impl(Bytecode::Executable const&) const
{
return "LeaveUnwindContext";