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LibJS: Implement async functions as generator functions in BC mode

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This applies a simple transformation, and adds a simple wrapper that
translates the generator interface to the async function interface.
This commit is contained in:
Ali Mohammad Pur 2021-11-11 00:46:07 +03:30 • committed by Linus Groh
parent c604e95993
commit 3b0bf05fa5
14 changed files with 192 additions and 43 deletions
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19
Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp
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@ -13,6 +13,7 @@
#include <LibJS/Interpreter.h>
#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/Array.h>
#include <LibJS/Runtime/AsyncFunctionDriverWrapper.h>
#include <LibJS/Runtime/ECMAScriptFunctionObject.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/ExecutionContext.h>
@ -100,11 +101,10 @@ void ECMAScriptFunctionObject::initialize(GlobalObject& global_object)
MUST(prototype->define_property_or_throw(vm.names.constructor, { .value = this, .writable = true, .enumerable = false, .configurable = true }));
break;
case FunctionKind::Generator:
case FunctionKind::Async:
// prototype is "g1.prototype" in figure-2 (https://tc39.es/ecma262/img/figure-2.png)
prototype = global_object.generator_object_prototype();
break;
case FunctionKind::Async:
break;
}
define_direct_property(vm.names.prototype, prototype, Attribute::Writable);
}
@ -753,12 +753,10 @@ Completion ECMAScriptFunctionObject::ordinary_call_evaluate_body()
auto* bytecode_interpreter = Bytecode::Interpreter::current();
if (bytecode_interpreter) {
if (m_kind == FunctionKind::Async)
return vm.throw_completion<InternalError>(global_object(), ErrorType::NotImplemented, "Async function execution in Bytecode interpreter");
// FIXME: pass something to evaluate default arguments with
TRY(function_declaration_instantiation(nullptr));
if (!m_bytecode_executable.has_value()) {
m_bytecode_executable = Bytecode::Generator::generate(m_ecmascript_code, m_kind == FunctionKind::Generator);
m_bytecode_executable = Bytecode::Generator::generate(m_ecmascript_code, m_kind);
m_bytecode_executable->name = m_name;
auto& passes = JS::Bytecode::Interpreter::optimization_pipeline();
passes.perform(*m_bytecode_executable);
@ -778,10 +776,17 @@ Completion ECMAScriptFunctionObject::ordinary_call_evaluate_body()
// NOTE: Running the bytecode should eventually return a completion.
// Until it does, we assume "return" and include the undefined fallback from the call site.
if (m_kind != FunctionKind::Generator)
if (m_kind == FunctionKind::Regular)
return { Completion::Type::Return, result.value_or(js_undefined()), {} };
auto generator_object = TRY(GeneratorObject::create(global_object(), result, this, vm.running_execution_context().lexical_environment, move(*result_and_frame.frame)));
auto generator_object = TRY(GeneratorObject::create(global_object(), result, this, vm.running_execution_context().copy(), move(*result_and_frame.frame)));
// NOTE: Async functions are entirely transformed to generator functions, and wrapped in a custom driver that returns a promise
// See AwaitExpression::generate_bytecode() for the transformation.
if (m_kind == FunctionKind::Async)
return { Completion::Type::Return, TRY(AsyncFunctionDriverWrapper::create(global_object(), generator_object)), {} };
VERIFY(m_kind == FunctionKind::Generator);
return { Completion::Type::Return, generator_object, {} };
} else {
if (m_kind == FunctionKind::Generator)