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LibJS: Move scope stack from VM back to Interpreter

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Okay, my vision here is improving. Interpreter should be a thing that
executes an AST. The scope stack is irrelevant to the VM proper,
so we can move that to the Interpreter. Same with execute_statement().
This commit is contained in:
Andreas Kling 2020-09-27 16:56:58 +02:00
parent 6861c619c6
commit be31805e8b
6 changed files with 124 additions and 119 deletions
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87
Libraries/LibJS/Interpreter.cpp
View file

@ -106,4 +106,91 @@ Value Interpreter::call_internal(Function& function, Value this_value, Optional<
return result;
}
void Interpreter::enter_scope(const ScopeNode& scope_node, ArgumentVector arguments, ScopeType scope_type, GlobalObject& global_object)
{
for (auto& declaration : scope_node.functions()) {
auto* function = ScriptFunction::create(global_object, declaration.name(), declaration.body(), declaration.parameters(), declaration.function_length(), current_environment());
vm().set_variable(declaration.name(), function, global_object);
}
if (scope_type == ScopeType::Function) {
m_scope_stack.append({ scope_type, scope_node, false });
return;
}
HashMap<FlyString, Variable> scope_variables_with_declaration_kind;
scope_variables_with_declaration_kind.ensure_capacity(16);
for (auto& declaration : scope_node.variables()) {
for (auto& declarator : declaration.declarations()) {
if (scope_node.is_program()) {
global_object.put(declarator.id().string(), js_undefined());
if (exception())
return;
} else {
scope_variables_with_declaration_kind.set(declarator.id().string(), { js_undefined(), declaration.declaration_kind() });
}
}
}
for (auto& argument : arguments) {
scope_variables_with_declaration_kind.set(argument.name, { argument.value, DeclarationKind::Var });
}
bool pushed_lexical_environment = false;
if (!scope_variables_with_declaration_kind.is_empty()) {
auto* block_lexical_environment = heap().allocate<LexicalEnvironment>(global_object, move(scope_variables_with_declaration_kind), current_environment());
vm().call_stack().last().environment = block_lexical_environment;
pushed_lexical_environment = true;
}
m_scope_stack.append({ scope_type, scope_node, pushed_lexical_environment });
}
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 = vm().call_frame().environment->parent();
if (popped_scope.scope_node.ptr() == &scope_node)
break;
}
// If we unwind all the way, just reset m_unwind_until so that future "return" doesn't break.
if (m_scope_stack.is_empty())
vm().unwind(ScopeType::None);
}
Value Interpreter::execute_statement(GlobalObject& global_object, const Statement& statement, ArgumentVector arguments, ScopeType scope_type)
{
if (!statement.is_scope_node())
return statement.execute(*this, global_object);
auto& block = static_cast<const ScopeNode&>(statement);
enter_scope(block, move(arguments), scope_type, global_object);
if (block.children().is_empty())
vm().set_last_value({}, js_undefined());
for (auto& node : block.children()) {
vm().set_last_value({}, node.execute(*this, global_object));
if (vm().should_unwind()) {
if (!block.label().is_null() && vm().should_unwind_until(ScopeType::Breakable, block.label()))
vm().stop_unwind();
break;
}
}
bool did_return = vm().unwind_until() == ScopeType::Function;
if (vm().unwind_until() == scope_type)
vm().unwind(ScopeType::None);
exit_scope(block);
return did_return ? vm().last_value() : js_undefined();
}
}