ladybird/Libraries/LibJS/Runtime/VM.cpp
Andreas Kling 7b863330dc LibJS: Cache commonly used FlyStrings in the VM
Roughly 7% of test-js runtime was spent creating FlyStrings from string
literals. This patch frontloads that work and caches all the commonly
used names in LibJS on a CommonPropertyNames struct that hangs off VM.
2020-10-13 23:57:45 +02:00

330 lines
11 KiB
C++

/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <AK/ScopeGuard.h>
#include <AK/StringBuilder.h>
#include <LibJS/Interpreter.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/Reference.h>
#include <LibJS/Runtime/ScriptFunction.h>
#include <LibJS/Runtime/Symbol.h>
#include <LibJS/Runtime/VM.h>
//#define VM_DEBUG
namespace JS {
NonnullRefPtr<VM> VM::create()
{
return adopt(*new VM);
}
VM::VM()
: m_heap(*this)
{
m_empty_string = m_heap.allocate_without_global_object<PrimitiveString>(String::empty());
#define __JS_ENUMERATE(SymbolName, snake_name) \
m_well_known_symbol_##snake_name = js_symbol(*this, "Symbol." #SymbolName, false);
JS_ENUMERATE_WELL_KNOWN_SYMBOLS
#undef __JS_ENUMERATE
}
VM::~VM()
{
}
Interpreter& VM::interpreter()
{
ASSERT(!m_interpreters.is_empty());
return *m_interpreters.last();
}
Interpreter* VM::interpreter_if_exists()
{
if (m_interpreters.is_empty())
return nullptr;
return m_interpreters.last();
}
void VM::push_interpreter(Interpreter& interpreter)
{
m_interpreters.append(&interpreter);
}
void VM::pop_interpreter(Interpreter& interpreter)
{
ASSERT(!m_interpreters.is_empty());
auto* popped_interpreter = m_interpreters.take_last();
ASSERT(popped_interpreter == &interpreter);
}
VM::InterpreterExecutionScope::InterpreterExecutionScope(Interpreter& interpreter)
: m_interpreter(interpreter)
{
m_interpreter.vm().push_interpreter(m_interpreter);
}
VM::InterpreterExecutionScope::~InterpreterExecutionScope()
{
m_interpreter.vm().pop_interpreter(m_interpreter);
}
void VM::gather_roots(HashTable<Cell*>& roots)
{
roots.set(m_empty_string);
if (m_exception)
roots.set(m_exception);
if (m_last_value.is_cell())
roots.set(m_last_value.as_cell());
for (auto& call_frame : m_call_stack) {
if (call_frame.this_value.is_cell())
roots.set(call_frame.this_value.as_cell());
for (auto& argument : call_frame.arguments) {
if (argument.is_cell())
roots.set(argument.as_cell());
}
roots.set(call_frame.environment);
}
#define __JS_ENUMERATE(SymbolName, snake_name) \
roots.set(well_known_symbol_##snake_name());
JS_ENUMERATE_WELL_KNOWN_SYMBOLS
#undef __JS_ENUMERATE
for (auto& symbol : m_global_symbol_map)
roots.set(symbol.value);
}
Symbol* VM::get_global_symbol(const String& description)
{
auto result = m_global_symbol_map.get(description);
if (result.has_value())
return result.value();
auto new_global_symbol = js_symbol(*this, description, true);
m_global_symbol_map.set(description, new_global_symbol);
return new_global_symbol;
}
void VM::set_variable(const FlyString& name, Value value, GlobalObject& global_object, bool first_assignment)
{
if (m_call_stack.size()) {
for (auto* environment = current_environment(); environment; environment = environment->parent()) {
if (environment->type() == LexicalEnvironment::EnvironmentRecordType::Global)
break;
auto possible_match = environment->get(name);
if (possible_match.has_value()) {
if (!first_assignment && possible_match.value().declaration_kind == DeclarationKind::Const) {
throw_exception<TypeError>(global_object, ErrorType::InvalidAssignToConst);
return;
}
environment->set(global_object, name, { value, possible_match.value().declaration_kind });
return;
}
}
}
global_object.put(move(name), move(value));
}
Value VM::get_variable(const FlyString& name, GlobalObject& global_object)
{
if (m_call_stack.size()) {
for (auto* environment = current_environment(); environment; environment = environment->parent()) {
if (environment->type() == LexicalEnvironment::EnvironmentRecordType::Global)
break;
auto possible_match = environment->get(name);
if (possible_match.has_value())
return possible_match.value().value;
}
}
auto value = global_object.get(name);
if (m_underscore_is_last_value && name == "_" && value.is_empty())
return m_last_value;
return value;
}
Reference VM::get_reference(const FlyString& name)
{
if (m_call_stack.size()) {
for (auto* environment = current_environment(); environment; environment = environment->parent()) {
if (environment->type() == LexicalEnvironment::EnvironmentRecordType::Global)
break;
auto possible_match = environment->get(name);
if (possible_match.has_value())
return { Reference::LocalVariable, name };
}
}
return { Reference::GlobalVariable, name };
}
Value VM::construct(Function& function, Function& new_target, Optional<MarkedValueList> arguments, GlobalObject& global_object)
{
auto& call_frame = push_call_frame(function.is_strict_mode());
ArmedScopeGuard call_frame_popper = [&] {
pop_call_frame();
};
call_frame.function_name = function.name();
call_frame.arguments = function.bound_arguments();
if (arguments.has_value())
call_frame.arguments.append(arguments.value().values());
call_frame.environment = function.create_environment();
current_environment()->set_new_target(&new_target);
Object* new_object = nullptr;
if (function.constructor_kind() == Function::ConstructorKind::Base) {
new_object = Object::create_empty(global_object);
current_environment()->bind_this_value(global_object, new_object);
if (exception())
return {};
auto prototype = new_target.get(names.prototype);
if (exception())
return {};
if (prototype.is_object()) {
new_object->set_prototype(&prototype.as_object());
if (exception())
return {};
}
}
// If we are a Derived constructor, |this| has not been constructed before super is called.
Value this_value = function.constructor_kind() == Function::ConstructorKind::Base ? new_object : Value {};
call_frame.this_value = this_value;
auto result = function.construct(new_target);
this_value = current_environment()->get_this_binding(global_object);
pop_call_frame();
call_frame_popper.disarm();
// If we are constructing an instance of a derived class,
// set the prototype on objects created by constructors that return an object (i.e. NativeFunction subclasses).
if (function.constructor_kind() == Function::ConstructorKind::Base && new_target.constructor_kind() == Function::ConstructorKind::Derived && result.is_object()) {
current_environment()->replace_this_binding(result);
auto prototype = new_target.get(names.prototype);
if (exception())
return {};
if (prototype.is_object()) {
result.as_object().set_prototype(&prototype.as_object());
if (exception())
return {};
}
return result;
}
if (exception())
return {};
if (result.is_object())
return result;
return this_value;
}
void VM::throw_exception(Exception* exception)
{
#ifdef VM_DEBUG
if (exception->value().is_object() && exception->value().as_object().is_error()) {
auto& error = static_cast<Error&>(exception->value().as_object());
dbgln("Throwing JavaScript Error: {}, {}", error.name(), error.message());
for (ssize_t i = m_call_stack.size() - 1; i >= 0; --i) {
auto function_name = m_call_stack[i].function_name;
if (function_name.is_empty())
function_name = "<anonymous>";
dbgln(" {}", function_name);
}
}
#endif
m_exception = exception;
unwind(ScopeType::Try);
}
String VM::join_arguments() const
{
StringBuilder joined_arguments;
for (size_t i = 0; i < argument_count(); ++i) {
joined_arguments.append(argument(i).to_string_without_side_effects().characters());
if (i != argument_count() - 1)
joined_arguments.append(' ');
}
return joined_arguments.build();
}
Value VM::resolve_this_binding(GlobalObject& global_object) const
{
return get_this_environment()->get_this_binding(global_object);
}
const LexicalEnvironment* VM::get_this_environment() const
{
// We will always return because the Global environment will always be reached, which has a |this| binding.
for (const LexicalEnvironment* environment = current_environment(); environment; environment = environment->parent()) {
if (environment->has_this_binding())
return environment;
}
ASSERT_NOT_REACHED();
}
Value VM::get_new_target() const
{
return get_this_environment()->new_target();
}
Value VM::call_internal(Function& function, Value this_value, Optional<MarkedValueList> arguments)
{
ASSERT(!exception());
auto& call_frame = push_call_frame(function.is_strict_mode());
call_frame.function_name = function.name();
call_frame.this_value = function.bound_this().value_or(this_value);
call_frame.arguments = function.bound_arguments();
if (arguments.has_value())
call_frame.arguments.append(move(arguments.release_value().values()));
call_frame.environment = function.create_environment();
ASSERT(call_frame.environment->this_binding_status() == LexicalEnvironment::ThisBindingStatus::Uninitialized);
call_frame.environment->bind_this_value(function.global_object(), call_frame.this_value);
auto result = function.call();
pop_call_frame();
return result;
}
bool VM::in_strict_mode() const
{
if (call_stack().is_empty())
return false;
return call_frame().is_strict_mode;
}
}