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LibJS: More properly implement scoping rules in bytecode codegen

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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
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12
Userland/Libraries/LibJS/Runtime/DeclarativeEnvironment.cpp
View file

@ -196,15 +196,21 @@ ThrowCompletionOr<bool> DeclarativeEnvironment::delete_binding(GlobalObject&, Fl
return true;
}
void DeclarativeEnvironment::initialize_or_set_mutable_binding(Badge<ScopeNode>, GlobalObject& global_object, FlyString const& name, Value value)
ThrowCompletionOr<void> DeclarativeEnvironment::initialize_or_set_mutable_binding(GlobalObject& global_object, FlyString const& name, Value value)
{
auto it = m_names.find(name);
VERIFY(it != m_names.end());
auto& binding = m_bindings[it->value];
if (!binding.initialized)
MUST(initialize_binding(global_object, name, value));
TRY(initialize_binding(global_object, name, value));
else
MUST(set_mutable_binding(global_object, name, value, false));
TRY(set_mutable_binding(global_object, name, value, false));
return {};
}
void DeclarativeEnvironment::initialize_or_set_mutable_binding(Badge<ScopeNode>, GlobalObject& global_object, FlyString const& name, Value value)
{
MUST(initialize_or_set_mutable_binding(global_object, name, value));
}
Vector<String> DeclarativeEnvironment::bindings() const

1
Userland/Libraries/LibJS/Runtime/DeclarativeEnvironment.h
View file

@ -31,6 +31,7 @@ public:
virtual ThrowCompletionOr<bool> delete_binding(GlobalObject&, FlyString const& name) override;
void initialize_or_set_mutable_binding(Badge<ScopeNode>, GlobalObject& global_object, FlyString const& name, Value value);
ThrowCompletionOr<void> initialize_or_set_mutable_binding(GlobalObject& global_object, FlyString const& name, Value value);
// This is not a method defined in the spec! Do not use this in any LibJS (or other spec related) code.
[[nodiscard]] Vector<String> bindings() const;

16
Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp
View file

@ -542,14 +542,16 @@ ThrowCompletionOr<void> ECMAScriptFunctionObject::function_declaration_instantia
if (!scope_body)
return {};
scope_body->for_each_lexically_scoped_declaration([&](Declaration const& declaration) {
declaration.for_each_bound_name([&](auto const& name) {
if (declaration.is_constant_declaration())
MUST(lex_environment->create_immutable_binding(global_object(), name, true));
else
MUST(lex_environment->create_mutable_binding(global_object(), name, false));
if (!Bytecode::Interpreter::current()) {
scope_body->for_each_lexically_scoped_declaration([&](Declaration const& declaration) {
declaration.for_each_bound_name([&](auto const& name) {
if (declaration.is_constant_declaration())
MUST(lex_environment->create_immutable_binding(global_object(), name, true));
else
MUST(lex_environment->create_mutable_binding(global_object(), name, false));
});
});
});
}
auto* private_environment = callee_context.private_environment;
for (auto& declaration : functions_to_initialize) {

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

@ -97,7 +97,7 @@ ThrowCompletionOr<Value> GeneratorObject::next_impl(VM& vm, GlobalObject& global
VERIFY(!m_generating_function->bytecode_executable()->basic_blocks.find_if([next_block](auto& block) { return block == next_block; }).is_end());
// Restore the snapshot registers
bytecode_interpreter->enter_frame(m_frame);
bytecode_interpreter->enter_frame(*m_frame);
// Temporarily switch to the captured execution context
TRY(vm.push_execution_context(m_execution_context, global_object));

2
Userland/Libraries/LibJS/Runtime/GeneratorObject.h
View file

@ -29,7 +29,7 @@ private:
ExecutionContext m_execution_context;
ECMAScriptFunctionObject* m_generating_function { nullptr };
Value m_previous_value;
Bytecode::RegisterWindow m_frame;
Optional<Bytecode::RegisterWindow> m_frame;
bool m_done { false };
};