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LibJS: Make return control flow more static

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With this only `ContinuePendingUnwind` needs to dynamically check if a
scheduled return needs to go through a `finally` block, making the
interpreter loop a bit nicer
This commit is contained in:
Hendiadyoin1 2024-05-12 11:03:26 +02:00 • committed by Andreas Kling
parent 73fdd31124
commit c8e4499b08
Notes: sideshowbarker 2024-07-17 03:30:41 +09:00
4 changed files with 54 additions and 38 deletions
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40
Userland/Libraries/LibJS/Bytecode/Interpreter.cpp
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@ -356,8 +356,6 @@ 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:
for (;;) {
@ -486,7 +484,19 @@ FLATTEN_ON_CLANG void Interpreter::run_bytecode(size_t entry_point)
}
if (!saved_return_value().is_empty()) {
do_return(saved_return_value());
goto run_finalizer_and_return;
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;
}
}
return;
}
auto const old_scheduled_jump = running_execution_context.previously_scheduled_jumps.take_last();
if (m_scheduled_jump.has_value()) {
@ -639,14 +649,13 @@ FLATTEN_ON_CLANG void Interpreter::run_bytecode(size_t entry_point)
handle_Await: {
auto& instruction = *reinterpret_cast<Op::Await const*>(&bytecode[program_counter]);
instruction.execute_impl(*this);
will_yield = true;
goto run_finalizer_and_return;
return;
}
handle_Return: {
auto& instruction = *reinterpret_cast<Op::Return const*>(&bytecode[program_counter]);
instruction.execute_impl(*this);
goto run_finalizer_and_return;
return;
}
handle_Yield: {
@ -657,27 +666,10 @@ FLATTEN_ON_CLANG void Interpreter::run_bytecode(size_t entry_point)
// 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;
return;
}
}
}
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;
}
}
}
}
Interpreter::ResultAndReturnRegister Interpreter::run_executable(Executable& executable, Optional<size_t> entry_point, Value initial_accumulator_value)