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LibJS: Split the per-call-frame environment into lexical and variable

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To better follow the spec, we need to distinguish between the current
execution context's lexical environment and variable environment.

This patch moves us to having two record pointers, although both of
them point at the same environment records for now.
This commit is contained in:
Andreas Kling 2021-06-22 15:42:44 +02:00
parent aabd82d508
commit 1d20380859
13 changed files with 52 additions and 41 deletions
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22
Userland/Libraries/LibJS/Interpreter.cpp
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@ -50,7 +50,8 @@ void Interpreter::run(GlobalObject& global_object, const Program& program)
global_call_frame.this_value = &global_object;
static FlyString global_execution_context_name = "(global execution context)";
global_call_frame.function_name = global_execution_context_name;
global_call_frame.environment_record = &global_object;
global_call_frame.lexical_environment = &global_object;
global_call_frame.variable_environment = &global_object;
VERIFY(!vm.exception());
global_call_frame.is_strict_mode = program.is_strict_mode();
vm.push_call_frame(global_call_frame, global_object);
@ -83,7 +84,7 @@ void Interpreter::enter_scope(const ScopeNode& scope_node, ScopeType scope_type,
{
ScopeGuard guard([&] {
for (auto& declaration : scope_node.functions()) {
auto* function = ScriptFunction::create(global_object, declaration.name(), declaration.body(), declaration.parameters(), declaration.function_length(), current_environment_record(), declaration.kind(), declaration.is_strict_mode());
auto* function = ScriptFunction::create(global_object, declaration.name(), declaration.body(), declaration.parameters(), declaration.function_length(), lexical_environment(), declaration.kind(), declaration.is_strict_mode());
vm().set_variable(declaration.name(), function, global_object);
}
});
@ -91,7 +92,7 @@ void Interpreter::enter_scope(const ScopeNode& scope_node, ScopeType scope_type,
if (scope_type == ScopeType::Function) {
push_scope({ scope_type, scope_node, false });
for (auto& declaration : scope_node.functions())
current_environment_record()->put_into_environment_record(declaration.name(), { js_undefined(), DeclarationKind::Var });
lexical_environment()->put_into_environment_record(declaration.name(), { js_undefined(), DeclarationKind::Var });
return;
}
@ -131,8 +132,9 @@ void Interpreter::enter_scope(const ScopeNode& scope_node, ScopeType scope_type,
bool pushed_environment_record = false;
if (!scope_variables_with_declaration_kind.is_empty()) {
auto* environment_record = heap().allocate<DeclarativeEnvironmentRecord>(global_object, move(scope_variables_with_declaration_kind), current_environment_record());
vm().call_frame().environment_record = environment_record;
auto* environment_record = heap().allocate<DeclarativeEnvironmentRecord>(global_object, move(scope_variables_with_declaration_kind), lexical_environment());
vm().call_frame().lexical_environment = environment_record;
vm().call_frame().variable_environment = environment_record;
pushed_environment_record = true;
}
@ -143,8 +145,10 @@ void Interpreter::exit_scope(const ScopeNode& scope_node)
{
while (!m_scope_stack.is_empty()) {
auto popped_scope = m_scope_stack.take_last();
if (popped_scope.pushed_environment)
vm().call_frame().environment_record = vm().call_frame().environment_record->outer_environment();
if (popped_scope.pushed_environment) {
vm().call_frame().lexical_environment = vm().call_frame().lexical_environment->outer_environment();
vm().call_frame().variable_environment = vm().call_frame().variable_environment->outer_environment();
}
if (popped_scope.scope_node.ptr() == &scope_node)
break;
}
@ -195,8 +199,8 @@ Value Interpreter::execute_statement(GlobalObject& global_object, const Statemen
FunctionEnvironmentRecord* Interpreter::current_function_environment_record()
{
VERIFY(is<FunctionEnvironmentRecord>(vm().call_frame().environment_record));
return static_cast<FunctionEnvironmentRecord*>(vm().call_frame().environment_record);
VERIFY(is<FunctionEnvironmentRecord>(vm().call_frame().lexical_environment));
return static_cast<FunctionEnvironmentRecord*>(vm().call_frame().lexical_environment);
}
}