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LibJS: Inline flow control ops in the bytecode interpreter loop

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Instead of calling out to helper functions for flow control (and then
checking control flags on every iteration), we now simply inline those
ops in the interpreter loop directly.
This commit is contained in:
Andreas Kling 2023-09-26 19:43:44 +02:00
parent 39cfb64269
commit e5474c384d
3 changed files with 80 additions and 79 deletions
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87
Userland/Libraries/LibJS/Bytecode/Interpreter.cpp
View file

@ -171,12 +171,67 @@ void Interpreter::run_bytecode()
bool will_return = false;
bool will_yield = false;
ThrowCompletionOr<void> result;
while (!pc.at_end()) {
auto& instruction = *pc;
auto ran_or_error = instruction.execute(*this);
if (ran_or_error.is_error()) [[unlikely]] {
reg(Register::exception()) = *ran_or_error.throw_completion().value();
switch (instruction.type()) {
case Instruction::Type::Jump:
m_current_block = &static_cast<Op::Jump const&>(instruction).true_target()->block();
goto start;
case Instruction::Type::JumpConditional:
if (accumulator().to_boolean())
m_current_block = &static_cast<Op::Jump const&>(instruction).true_target()->block();
else
m_current_block = &static_cast<Op::Jump const&>(instruction).false_target()->block();
goto start;
case Instruction::Type::JumpNullish:
if (accumulator().is_nullish())
m_current_block = &static_cast<Op::Jump const&>(instruction).true_target()->block();
else
m_current_block = &static_cast<Op::Jump const&>(instruction).false_target()->block();
goto start;
case Instruction::Type::JumpUndefined:
if (accumulator().is_undefined())
m_current_block = &static_cast<Op::Jump const&>(instruction).true_target()->block();
else
m_current_block = &static_cast<Op::Jump const&>(instruction).false_target()->block();
goto start;
case Instruction::Type::EnterUnwindContext:
enter_unwind_context(
static_cast<Op::EnterUnwindContext const&>(instruction).handler_target(),
static_cast<Op::EnterUnwindContext const&>(instruction).finalizer_target());
m_current_block = &static_cast<Op::EnterUnwindContext const&>(instruction).entry_point().block();
goto start;
case Instruction::Type::ContinuePendingUnwind:
if (auto exception = reg(Register::exception()); !exception.is_empty()) {
result = throw_completion(exception);
break;
}
if (!saved_return_value().is_empty()) {
do_return(saved_return_value());
break;
}
if (m_scheduled_jump) {
// FIXME: If we `break` or `continue` in the finally, we need to clear
// this field
m_current_block = exchange(m_scheduled_jump, nullptr);
} else {
m_current_block = &static_cast<Op::ContinuePendingUnwind const&>(instruction).resume_target().block();
}
goto start;
case Instruction::Type::ScheduleJump:
m_scheduled_jump = &static_cast<Op::ScheduleJump const&>(instruction).target().block();
m_current_block = unwind_contexts().last().finalizer;
goto start;
default:
result = instruction.execute(*this);
break;
}
if (result.is_error()) [[unlikely]] {
reg(Register::exception()) = *result.throw_completion().value();
if (unwind_contexts().is_empty())
return;
auto& unwind_context = unwind_contexts().last();
@ -204,10 +259,7 @@ void Interpreter::run_bytecode()
// If you run into this, you probably forgot to remove the current unwind_context somewhere.
VERIFY_NOT_REACHED();
}
if (m_pending_jump.has_value()) {
m_current_block = m_pending_jump.release_value();
goto start;
}
if (!reg(Register::return_value()).is_empty()) {
will_return = true;
// Note: A `yield` statement will not go through a finally statement,
@ -315,27 +367,6 @@ void Interpreter::leave_unwind_context()
unwind_contexts().take_last();
}
ThrowCompletionOr<void> Interpreter::continue_pending_unwind(Label const& resume_label)
{
if (auto exception = reg(Register::exception()); !exception.is_empty())
return throw_completion(exception);
if (!saved_return_value().is_empty()) {
do_return(saved_return_value());
return {};
}
if (m_scheduled_jump) {
// FIXME: If we `break` or `continue` in the finally, we need to clear
// this field
jump(Label { *m_scheduled_jump });
m_scheduled_jump = nullptr;
} else {
jump(resume_label);
}
return {};
}
ThrowCompletionOr<NonnullOwnPtr<Bytecode::Executable>> compile(VM& vm, ASTNode const& node, FunctionKind kind, DeprecatedFlyString const& name)
{
auto executable_result = Bytecode::Generator::generate(node, kind);