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LibJS/Bytecode: Streamline return/yield flow a bit in the interpreter

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This commit is contained in:
Andreas Kling 2024-05-10 07:56:39 +02:00 • committed by Alexander Kalenik
commit a77c6e15f4
Notes: sideshowbarker 2024-07-18 08:59:31 +09:00
1 changed files with 26 additions and 39 deletions
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65
Userland/Libraries/LibJS/Bytecode/Interpreter.cpp
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@ -374,11 +374,10 @@ FLATTEN_ON_CLANG void Interpreter::run_bytecode(size_t entry_point)
goto* bytecode_dispatch_table[static_cast<size_t>(next_instruction.type())]; \
} while (0)
bool will_yield = false;
for (;;) {
start:
bool will_return = false;
bool will_yield = false;
for (;;) {
goto* bytecode_dispatch_table[static_cast<size_t>((*reinterpret_cast<Instruction const*>(&bytecode[program_counter])).type())];
@ -487,7 +486,7 @@ FLATTEN_ON_CLANG void Interpreter::run_bytecode(size_t entry_point)
}
if (!saved_return_value().is_empty()) {
do_return(saved_return_value());
goto may_return;
goto run_finalizer_and_return;
}
auto const old_scheduled_jump = running_execution_context.previously_scheduled_jumps.take_last();
if (m_scheduled_jump.has_value()) {
@ -631,56 +630,44 @@ FLATTEN_ON_CLANG void Interpreter::run_bytecode(size_t entry_point)
handle_Await: {
auto& instruction = *reinterpret_cast<Op::Await const*>(&bytecode[program_counter]);
(void)instruction.execute_impl(*this);
goto may_return;
will_yield = true;
goto run_finalizer_and_return;
}
handle_Return: {
auto& instruction = *reinterpret_cast<Op::Return const*>(&bytecode[program_counter]);
(void)instruction.execute_impl(*this);
goto may_return;
goto run_finalizer_and_return;
}
handle_Yield: {
auto& instruction = *reinterpret_cast<Op::Yield const*>(&bytecode[program_counter]);
(void)instruction.execute_impl(*this);
goto may_return;
}
may_return: {
auto& instruction = *reinterpret_cast<Instruction const*>(&bytecode[program_counter]);
if (!reg(Register::return_value()).is_empty()) {
will_return = true;
// Note: A `yield` statement will not go through a finally statement,
// hence we need to set a flag to not do so,
// but we generate a Yield Operation in the case of returns in
// generators as well, so we need to check if it will actually
// continue or is a `return` in disguise
will_yield = (instruction.type() == Instruction::Type::Yield && static_cast<Op::Yield const&>(instruction).continuation().has_value()) || instruction.type() == Instruction::Type::Await;
break;
}
program_counter += instruction.length();
goto start;
// Note: A `yield` statement will not go through a finally statement,
// hence we need to set a flag to not do so,
// but we generate a Yield Operation in the case of returns in
// generators as well, so we need to check if it will actually
// continue or is a `return` in disguise
will_yield = instruction.continuation().has_value();
goto run_finalizer_and_return;
}
}
}
if (!will_yield) {
if (auto handlers = executable.exception_handlers_for_offset(program_counter); handlers.has_value()) {
if (auto finalizer = handlers.value().finalizer_offset; finalizer.has_value()) {
VERIFY(!running_execution_context.unwind_contexts.is_empty());
auto& unwind_context = running_execution_context.unwind_contexts.last();
VERIFY(unwind_context.executable == m_current_executable);
reg(Register::saved_return_value()) = reg(Register::return_value());
reg(Register::return_value()) = {};
program_counter = finalizer.value();
// the unwind_context will be pop'ed when entering the finally block
continue;
}
run_finalizer_and_return:
if (!will_yield) {
if (auto handlers = executable.exception_handlers_for_offset(program_counter); handlers.has_value()) {
if (auto finalizer = handlers.value().finalizer_offset; finalizer.has_value()) {
VERIFY(!running_execution_context.unwind_contexts.is_empty());
auto& unwind_context = running_execution_context.unwind_contexts.last();
VERIFY(unwind_context.executable == m_current_executable);
reg(Register::saved_return_value()) = reg(Register::return_value());
reg(Register::return_value()) = {};
program_counter = finalizer.value();
// the unwind_context will be pop'ed when entering the finally block
goto start;
}
}
if (will_return)
break;
}
}