RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 19:27:44 +00:00
Code Issues Activity Actions

LibJS: Cache access to bindings in the global environment

Browse source 
This patch adds a special EnvironmentCoordinate::global_marker value
that signifies that a binding lookup ended up searching the global
environment. It doesn't matter if we find it there or not, the global
marker is always returned. This allows us to bypass other environments
on subsequent access, going directly to the global environment.
This commit is contained in:
Andreas Kling 2022-11-10 20:55:03 +01:00 • committed by Linus Groh
parent 7b30df0840
commit d7e5a2058d
4 changed files with 18 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

15
Userland/Libraries/LibJS/AST.cpp
View file

@ -1376,11 +1376,16 @@ ThrowCompletionOr<Reference> Expression::to_reference(Interpreter&) const
ThrowCompletionOr<Reference> Identifier::to_reference(Interpreter& interpreter) const ThrowCompletionOr<Reference> Identifier::to_reference(Interpreter& interpreter) const
{ {
if (m_cached_environment_coordinate.has_value()) { if (m_cached_environment_coordinate.has_value()) {
auto* environment = interpreter.vm().running_execution_context().lexical_environment; Environment* environment = nullptr;
for (size_t i = 0; i < m_cached_environment_coordinate->hops; ++i) if (m_cached_environment_coordinate->index == EnvironmentCoordinate::global_marker) {
environment = environment->outer_environment(); environment = &interpreter.vm().current_realm()->global_environment();
VERIFY(environment); } else {
VERIFY(environment->is_declarative_environment()); environment = interpreter.vm().running_execution_context().lexical_environment;
for (size_t i = 0; i < m_cached_environment_coordinate->hops; ++i)
environment = environment->outer_environment();
VERIFY(environment);
VERIFY(environment->is_declarative_environment());
}
if (!environment->is_permanently_screwed_by_eval()) { if (!environment->is_permanently_screwed_by_eval()) {
return Reference { *environment, string(), interpreter.vm().in_strict_mode(), m_cached_environment_coordinate }; return Reference { *environment, string(), interpreter.vm().in_strict_mode(), m_cached_environment_coordinate };
} }

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

@ -14,6 +14,8 @@ namespace JS {
struct EnvironmentCoordinate { struct EnvironmentCoordinate {
size_t hops { 0 }; size_t hops { 0 };
size_t index { 0 }; size_t index { 0 };
static constexpr size_t global_marker = 0xffffffff;
}; };
} }

5
Userland/Libraries/LibJS/Runtime/GlobalEnvironment.cpp
View file

@ -39,8 +39,11 @@ ThrowCompletionOr<Value> GlobalEnvironment::get_this_binding(VM&) const
} }
// 9.1.1.4.1 HasBinding ( N ), https://tc39.es/ecma262/#sec-global-environment-records-hasbinding-n // 9.1.1.4.1 HasBinding ( N ), https://tc39.es/ecma262/#sec-global-environment-records-hasbinding-n
ThrowCompletionOr<bool> GlobalEnvironment::has_binding(FlyString const& name, Optional<size_t>*) const ThrowCompletionOr<bool> GlobalEnvironment::has_binding(FlyString const& name, Optional<size_t>* out_index) const
{ {
if (out_index)
*out_index = EnvironmentCoordinate::global_marker;
// 1. Let DclRec be envRec.[[DeclarativeRecord]]. // 1. Let DclRec be envRec.[[DeclarativeRecord]].
// 2. If ! DclRec.HasBinding(N) is true, return true. // 2. If ! DclRec.HasBinding(N) is true, return true.
if (MUST(m_declarative_record->has_binding(name))) if (MUST(m_declarative_record->has_binding(name)))

4
Userland/Libraries/LibJS/Runtime/Reference.cpp
View file

@ -68,7 +68,7 @@ ThrowCompletionOr<void> Reference::put_value(VM& vm, Value value)
VERIFY(m_base_environment); VERIFY(m_base_environment);
// c. Return ? base.SetMutableBinding(V.[[ReferencedName]], W, V.[[Strict]]) (see 9.1). // c. Return ? base.SetMutableBinding(V.[[ReferencedName]], W, V.[[Strict]]) (see 9.1).
if (m_environment_coordinate.has_value()) if (m_environment_coordinate.has_value() && m_environment_coordinate->index != EnvironmentCoordinate::global_marker)
return static_cast<DeclarativeEnvironment*>(m_base_environment)->set_mutable_binding_direct(vm, m_environment_coordinate->index, value, m_strict); return static_cast<DeclarativeEnvironment*>(m_base_environment)->set_mutable_binding_direct(vm, m_environment_coordinate->index, value, m_strict);
else else
return m_base_environment->set_mutable_binding(vm, m_name.as_string(), value, m_strict); return m_base_environment->set_mutable_binding(vm, m_name.as_string(), value, m_strict);
@ -138,7 +138,7 @@ ThrowCompletionOr<Value> Reference::get_value(VM& vm) const
VERIFY(m_base_environment); VERIFY(m_base_environment);
// c. Return ? base.GetBindingValue(V.[[ReferencedName]], V.[[Strict]]) (see 9.1). // c. Return ? base.GetBindingValue(V.[[ReferencedName]], V.[[Strict]]) (see 9.1).
if (m_environment_coordinate.has_value()) if (m_environment_coordinate.has_value() && m_environment_coordinate->index != EnvironmentCoordinate::global_marker)
return static_cast<DeclarativeEnvironment*>(m_base_environment)->get_binding_value_direct(vm, m_environment_coordinate->index, m_strict); return static_cast<DeclarativeEnvironment*>(m_base_environment)->get_binding_value_direct(vm, m_environment_coordinate->index, m_strict);
return m_base_environment->get_binding_value(vm, m_name.as_string(), m_strict); return m_base_environment->get_binding_value(vm, m_name.as_string(), m_strict);
} }