1use crate::cell::RefCell;
2use crate::sys::thread_local::guard;
3
4#[thread_local]
5static DTORS: RefCell<Vec<(*mut u8, unsafe extern "C" fn(*mut u8))>> = RefCell::new(Vec::new());
6
7pub unsafe fn register(t: *mut u8, dtor: unsafe extern "C" fn(*mut u8)) {
8 let Ok(mut dtors: RefMut<'_, Vec<(*mut u8, …)>>) = DTORS.try_borrow_mut() else {
9 // This point can only be reached if the global allocator calls this
10 // function again.
11 // FIXME: maybe use the system allocator instead?
12 rtabort!("the global allocator may not use TLS with destructors");
13 };
14
15 guard::enable();
16
17 dtors.push((t, dtor));
18}
19
20/// The [`guard`] module contains platform-specific functions which will run this
21/// function on thread exit if [`guard::enable`] has been called.
22///
23/// # Safety
24///
25/// May only be run on thread exit to guarantee that there are no live references
26/// to TLS variables while they are destroyed.
27pub unsafe fn run() {
28 loop {
29 let mut dtors: RefMut<'_, Vec<(*mut u8, …)>> = DTORS.borrow_mut();
30 match dtors.pop() {
31 Some((t: *mut u8, dtor: unsafe fn(*mut u8))) => {
32 drop(dtors);
33 unsafe {
34 dtor(t);
35 }
36 }
37 None => {
38 // Free the list memory.
39 *dtors = Vec::new();
40 break;
41 }
42 }
43 }
44}
45