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/*
* Copyright (c) 2020, Stephan Unverwerth <s.unverwerth@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Debug.h>
#include <AK/Function.h>
#include <LibJS/AST.h>
#include <LibJS/Bytecode/BasicBlock.h>
#include <LibJS/Bytecode/Generator.h>
#include <LibJS/Bytecode/Interpreter.h>
#include <LibJS/Bytecode/PassManager.h>
#include <LibJS/Interpreter.h>
#include <LibJS/Runtime/Array.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/FunctionEnvironmentRecord.h>
#include <LibJS/Runtime/GeneratorObject.h>
#include <LibJS/Runtime/GeneratorObjectPrototype.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/NativeFunction.h>
#include <LibJS/Runtime/ScriptFunction.h>
#include <LibJS/Runtime/Value.h>
namespace JS {
static ScriptFunction* typed_this(VM& vm, GlobalObject& global_object)
{
auto* this_object = vm.this_value(global_object).to_object(global_object);
if (!this_object)
return nullptr;
if (!this_object->is_function()) {
vm.throw_exception<TypeError>(global_object, ErrorType::NotAFunctionNoParam);
return nullptr;
}
return static_cast<ScriptFunction*>(this_object);
}
ScriptFunction* ScriptFunction::create(GlobalObject& global_object, const FlyString& name, const Statement& body, Vector<FunctionNode::Parameter> parameters, i32 m_function_length, EnvironmentRecord* parent_scope, FunctionKind kind, bool is_strict, bool is_arrow_function)
{
Object* prototype = nullptr;
switch (kind) {
case FunctionKind::Regular:
prototype = global_object.function_prototype();
break;
case FunctionKind::Generator:
prototype = global_object.generator_function_prototype();
break;
}
return global_object.heap().allocate<ScriptFunction>(global_object, global_object, name, body, move(parameters), m_function_length, parent_scope, *prototype, kind, is_strict, is_arrow_function);
}
ScriptFunction::ScriptFunction(GlobalObject& global_object, const FlyString& name, const Statement& body, Vector<FunctionNode::Parameter> parameters, i32 function_length, EnvironmentRecord* parent_scope, Object& prototype, FunctionKind kind, bool is_strict, bool is_arrow_function)
: Function(is_arrow_function ? vm().this_value(global_object) : Value(), {}, prototype)
, m_name(name)
, m_body(body)
, m_parameters(move(parameters))
, m_parent_scope(parent_scope)
, m_function_length(function_length)
, m_kind(kind)
, m_is_strict(is_strict)
, m_is_arrow_function(is_arrow_function)
{
}
void ScriptFunction::initialize(GlobalObject& global_object)
{
auto& vm = this->vm();
Function::initialize(global_object);
if (!m_is_arrow_function) {
auto* prototype = vm.heap().allocate<Object>(global_object, *global_object.new_script_function_prototype_object_shape());
switch (m_kind) {
case FunctionKind::Regular:
prototype->define_property(vm.names.constructor, this, Attribute::Writable | Attribute::Configurable);
break;
case FunctionKind::Generator:
// prototype is "g1.prototype" in figure-2 (https://tc39.es/ecma262/img/figure-2.png)
prototype->set_prototype(global_object.generator_object_prototype());
break;
}
define_property(vm.names.prototype, prototype, Attribute::Writable);
}
define_native_property(vm.names.length, length_getter, {}, Attribute::Configurable);
define_native_property(vm.names.name, name_getter, {}, Attribute::Configurable);
}
ScriptFunction::~ScriptFunction()
{
}
void ScriptFunction::visit_edges(Visitor& visitor)
{
Function::visit_edges(visitor);
visitor.visit(m_parent_scope);
}
FunctionEnvironmentRecord* ScriptFunction::create_environment_record()
{
HashMap<FlyString, Variable> variables;
for (auto& parameter : m_parameters) {
parameter.binding.visit(
[&](const FlyString& name) { variables.set(name, { js_undefined(), DeclarationKind::Var }); },
[&](const NonnullRefPtr<BindingPattern>& binding) {
binding->for_each_bound_name([&](const auto& name) {
variables.set(name, { js_undefined(), DeclarationKind::Var });
});
});
}
if (is<ScopeNode>(body())) {
for (auto& declaration : static_cast<const ScopeNode&>(body()).variables()) {
for (auto& declarator : declaration.declarations()) {
declarator.target().visit(
[&](const NonnullRefPtr<Identifier>& id) {
variables.set(id->string(), { js_undefined(), declaration.declaration_kind() });
},
[&](const NonnullRefPtr<BindingPattern>& binding) {
binding->for_each_bound_name([&](const auto& name) {
variables.set(name, { js_undefined(), declaration.declaration_kind() });
});
});
}
}
}
auto* environment = heap().allocate<FunctionEnvironmentRecord>(global_object(), m_parent_scope, variables);
environment->set_function_object(*this);
if (m_is_arrow_function) {
if (is<FunctionEnvironmentRecord>(m_parent_scope))
environment->set_new_target(static_cast<FunctionEnvironmentRecord*>(m_parent_scope)->new_target());
}
return environment;
}
Value ScriptFunction::execute_function_body()
{
auto& vm = this->vm();
Interpreter* ast_interpreter = nullptr;
auto* bytecode_interpreter = Bytecode::Interpreter::current();
auto prepare_arguments = [&] {
auto& call_frame_args = vm.call_frame().arguments;
for (size_t i = 0; i < m_parameters.size(); ++i) {
auto& parameter = m_parameters[i];
parameter.binding.visit(
[&](const auto& param) {
Value argument_value;
if (parameter.is_rest) {
auto* array = Array::create(global_object());
for (size_t rest_index = i; rest_index < call_frame_args.size(); ++rest_index)
array->indexed_properties().append(call_frame_args[rest_index]);
argument_value = move(array);
} else if (i < call_frame_args.size() && !call_frame_args[i].is_undefined()) {
argument_value = call_frame_args[i];
} else if (parameter.default_value) {
// FIXME: Support default arguments in the bytecode world!
if (!bytecode_interpreter)
argument_value = parameter.default_value->execute(*ast_interpreter, global_object());
if (vm.exception())
return;
} else {
argument_value = js_undefined();
}
if (i >= call_frame_args.size())
call_frame_args.resize(i + 1);
call_frame_args[i] = argument_value;
vm.assign(param, argument_value, global_object(), true, vm.lexical_environment());
});
if (vm.exception())
return;
}
};
if (bytecode_interpreter) {
prepare_arguments();
if (!m_bytecode_executable.has_value()) {
m_bytecode_executable = Bytecode::Generator::generate(m_body, m_kind == FunctionKind::Generator);
auto& passes = JS::Bytecode::Interpreter::optimization_pipeline();
passes.perform(*m_bytecode_executable);
if constexpr (JS_BYTECODE_DEBUG) {
dbgln("Optimisation passes took {}us", passes.elapsed());
dbgln("Compiled Bytecode::Block for function '{}':", m_name);
for (auto& block : m_bytecode_executable->basic_blocks)
block.dump(*m_bytecode_executable);
}
}
auto result = bytecode_interpreter->run(*m_bytecode_executable);
if (m_kind != FunctionKind::Generator)
return result;
return GeneratorObject::create(global_object(), result, this, vm.call_frame().lexical_environment, bytecode_interpreter->snapshot_frame());
} else {
VERIFY(m_kind != FunctionKind::Generator);
OwnPtr<Interpreter> local_interpreter;
ast_interpreter = vm.interpreter_if_exists();
if (!ast_interpreter) {
local_interpreter = Interpreter::create_with_existing_global_object(global_object());
ast_interpreter = local_interpreter.ptr();
}
VM::InterpreterExecutionScope scope(*ast_interpreter);
prepare_arguments();
if (vm.exception())
return {};
return ast_interpreter->execute_statement(global_object(), m_body, ScopeType::Function);
}
}
Value ScriptFunction::call()
{
if (m_is_class_constructor) {
vm().throw_exception<TypeError>(global_object(), ErrorType::ClassConstructorWithoutNew, m_name);
return {};
}
return execute_function_body();
}
Value ScriptFunction::construct(Function&)
{
if (m_is_arrow_function || m_kind == FunctionKind::Generator) {
vm().throw_exception<TypeError>(global_object(), ErrorType::NotAConstructor, m_name);
return {};
}
return execute_function_body();
}
JS_DEFINE_NATIVE_GETTER(ScriptFunction::length_getter)
{
auto* function = typed_this(vm, global_object);
if (!function)
return {};
return Value(static_cast<i32>(function->m_function_length));
}
JS_DEFINE_NATIVE_GETTER(ScriptFunction::name_getter)
{
auto* function = typed_this(vm, global_object);
if (!function)
return {};
return js_string(vm, function->name().is_null() ? "" : function->name());
}
}
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