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LibJS: Get this from execution context for non-arrow functions

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Allows to skip function environment allocation for non-arrow functions
if the only reason it is needed is to hold `this` binding.

The parser is changed to do following:
- If a function is an arrow function and uses `this` then all functions
  in a scope chain are marked to allocate function environment for
  `this` binding.
- If a function uses `new.target` then all functions in a scope chain
  are marked to allocate function environment.

`ordinary_call_bind_this()` is changed to put `this` value in execution
context when function environment allocation is skipped.

35% improvement in Octane/typescript.js
50% improvement in Octane/deltablue.js
19% improvement in Octane/raytrace.js
This commit is contained in:
Aliaksandr Kalenik
2024-05-21 16:51:21 +01:00
committed by Andreas Kling
parent 7ae990d2e5
commit ebb3d8025c
13 changed files with 95 additions and 59 deletions
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5
Userland/Libraries/LibJS/SourceTextModule.cpp
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@@ -498,7 +498,8 @@ ThrowCompletionOr<void> SourceTextModule::initialize_environment(VM& vm)
DeprecatedFlyString function_name = function_declaration.name();
if (function_name == ExportStatement::local_name_for_default)
function_name = "default"sv;
auto function = ECMAScriptFunctionObject::create(realm(), function_name, function_declaration.source_text(), function_declaration.body(), function_declaration.parameters(), function_declaration.function_length(), function_declaration.local_variables_names(), environment, private_environment, function_declaration.kind(), function_declaration.is_strict_mode(), function_declaration.uses_this(), function_declaration.might_need_arguments_object(), function_declaration.contains_direct_call_to_eval());
auto function = ECMAScriptFunctionObject::create(realm(), function_name, function_declaration.source_text(), function_declaration.body(), function_declaration.parameters(), function_declaration.function_length(), function_declaration.local_variables_names(), environment, private_environment, function_declaration.kind(), function_declaration.is_strict_mode(),
function_declaration.uses_this_from_environment(), function_declaration.might_need_arguments_object(), function_declaration.contains_direct_call_to_eval());
// 2. Perform ! env.InitializeBinding(dn, fo, normal).
MUST(environment->initialize_binding(vm, name, function, Environment::InitializeBindingHint::Normal));
@@ -759,7 +760,7 @@ ThrowCompletionOr<void> SourceTextModule::execute_module(VM& vm, GCPtr<PromiseCa
auto module_wrapper_function = ECMAScriptFunctionObject::create(
realm(), "module code with top-level await", StringView {}, this->m_ecmascript_code,
{}, 0, {}, environment(), nullptr, FunctionKind::Async, true, UsesThis::Yes, false, false);
{}, 0, {}, environment(), nullptr, FunctionKind::Async, true, UsesThisFromEnvironment::Yes, false, false);
module_wrapper_function->set_is_module_wrapper(true);
// AD-HOC: We push/pop the moduleContext around the call to ensure that the async execution context