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Optimize WrappedFailure userdata detection.

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This is done by comparing a metatable pointer to previously saved one (it never changes).
This commit is contained in:
Alex Orlenko 2022-07-17 10:57:36 +01:00
parent f7ee6dc635
commit 059e41bafb
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GPG key ID: 4C150C250863B96D
2 changed files with 40 additions and 13 deletions
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17
src/lua.rs
View file

@ -111,6 +111,9 @@ pub(crate) struct ExtraData {
#[cfg(feature = "async")]
recycled_thread_cache: Vec<c_int>,
// Address of `WrappedFailure` metatable
wrapped_failure_mt_ptr: *const c_void,
// Index of `Option<Waker>` userdata on the ref thread
#[cfg(feature = "async")]
ref_waker_idx: c_int,
@ -538,6 +541,13 @@ impl Lua {
"Error while creating ref thread",
);
let wrapped_failure_mt_ptr = {
get_gc_metatable::<WrappedFailure>(state);
let ptr = ffi::lua_topointer(state, -1);
ffi::lua_pop(state, 1);
ptr
};
// Create empty Waker slot on the ref thread
#[cfg(feature = "async")]
let ref_waker_idx = {
@ -568,6 +578,7 @@ impl Lua {
multivalue_cache: Vec::with_capacity(MULTIVALUE_CACHE_SIZE),
#[cfg(feature = "async")]
recycled_thread_cache: Vec::new(),
wrapped_failure_mt_ptr,
#[cfg(feature = "async")]
ref_waker_idx,
#[cfg(not(feature = "luau"))]
@ -2293,6 +2304,8 @@ impl Lua {
// Uses 2 stack spaces, does not call checkstack
pub(crate) unsafe fn pop_value(&self) -> Value {
let state = self.state;
let extra = &mut *self.extra.get();
match ffi::lua_type(state, -1) {
ffi::LUA_TNIL => {
ffi::lua_pop(state, 1);
@ -2353,9 +2366,11 @@ impl Lua {
ffi::LUA_TFUNCTION => Value::Function(Function(self.pop_ref())),
ffi::LUA_TUSERDATA => {
let wrapped_failure_mt_ptr = extra.wrapped_failure_mt_ptr;
// We must prevent interaction with userdata types other than UserData OR a WrappedError.
// WrappedPanics are automatically resumed.
match get_gc_userdata::<WrappedFailure>(state, -1).as_mut() {
match get_gc_userdata::<WrappedFailure>(state, -1, wrapped_failure_mt_ptr).as_mut()
{
Some(WrappedFailure::Error(err)) => {
let err = err.clone();
ffi::lua_pop(state, 1);

36
src/util.rs
View file

@ -203,7 +203,7 @@ pub unsafe fn pop_error(state: *mut ffi::lua_State, err_code: c_int) -> Error {
"pop_error called with non-error return code"
);
match get_gc_userdata::<WrappedFailure>(state, -1).as_mut() {
match get_gc_userdata::<WrappedFailure>(state, -1, ptr::null()).as_mut() {
Some(WrappedFailure::Error(err)) => {
ffi::lua_pop(state, 1);
err.clone()
@ -394,16 +394,28 @@ pub unsafe fn push_gc_userdata<T: Any>(
}
// Uses 2 stack spaces, does not call checkstack
pub unsafe fn get_gc_userdata<T: Any>(state: *mut ffi::lua_State, index: c_int) -> *mut T {
pub unsafe fn get_gc_userdata<T: Any>(
state: *mut ffi::lua_State,
index: c_int,
mt_ptr: *const c_void,
) -> *mut T {
let ud = ffi::lua_touserdata(state, index) as *mut T;
if ud.is_null() || ffi::lua_getmetatable(state, index) == 0 {
return ptr::null_mut();
}
get_gc_metatable::<T>(state);
let res = ffi::lua_rawequal(state, -1, -2);
ffi::lua_pop(state, 2);
if res == 0 {
return ptr::null_mut();
if !mt_ptr.is_null() {
let ud_mt_ptr = ffi::lua_topointer(state, -1);
ffi::lua_pop(state, 1);
if !ptr::eq(ud_mt_ptr, mt_ptr) {
return ptr::null_mut();
}
} else {
get_gc_metatable::<T>(state);
let res = ffi::lua_rawequal(state, -1, -2);
ffi::lua_pop(state, 2);
if res == 0 {
return ptr::null_mut();
}
}
ud
}
@ -679,7 +691,7 @@ pub unsafe extern "C" fn error_traceback(state: *mut ffi::lua_State) -> c_int {
return 1;
}
if get_gc_userdata::<WrappedFailure>(state, -1).is_null() {
if get_gc_userdata::<WrappedFailure>(state, -1, ptr::null()).is_null() {
let s = ffi::luaL_tolstring(state, -1, ptr::null_mut());
if ffi::lua_checkstack(state, ffi::LUA_TRACEBACK_STACK) != 0 {
ffi::luaL_traceback(state, state, s, 0);
@ -706,7 +718,7 @@ pub unsafe extern "C" fn safe_pcall(state: *mut ffi::lua_State) -> c_int {
ffi::lua_gettop(state)
} else {
if let Some(WrappedFailure::Panic(_)) =
get_gc_userdata::<WrappedFailure>(state, -1).as_ref()
get_gc_userdata::<WrappedFailure>(state, -1, ptr::null()).as_ref()
{
ffi::lua_error(state);
}
@ -722,7 +734,7 @@ pub unsafe extern "C" fn safe_xpcall(state: *mut ffi::lua_State) -> c_int {
ffi::luaL_checkstack(state, 2, ptr::null());
if let Some(WrappedFailure::Panic(_)) =
get_gc_userdata::<WrappedFailure>(state, -1).as_ref()
get_gc_userdata::<WrappedFailure>(state, -1, ptr::null()).as_ref()
{
1
} else {
@ -752,7 +764,7 @@ pub unsafe extern "C" fn safe_xpcall(state: *mut ffi::lua_State) -> c_int {
ffi::lua_gettop(state) - 1
} else {
if let Some(WrappedFailure::Panic(_)) =
get_gc_userdata::<WrappedFailure>(state, -1).as_ref()
get_gc_userdata::<WrappedFailure>(state, -1, ptr::null()).as_ref()
{
ffi::lua_error(state);
}
@ -836,7 +848,7 @@ pub unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<()> {
callback_error(state, |_| {
check_stack(state, 3)?;
let err_buf = match get_gc_userdata::<WrappedFailure>(state, -1).as_ref() {
let err_buf = match get_gc_userdata::<WrappedFailure>(state, -1, ptr::null()).as_ref() {
Some(WrappedFailure::Error(error)) => {
let err_buf_key = &ERROR_PRINT_BUFFER_KEY as *const u8 as *const c_void;
ffi::lua_rawgetp(state, ffi::LUA_REGISTRYINDEX, err_buf_key);