src/libstd/sys/hermit/fast_thread_local.rs

   1 #![cfg(target_thread_local)]
   2 #![unstable(feature = "thread_local_internals", issue = "none")]
   3
   4 // Simplify dtor registration by using a list of destructors.
   5 // The this solution works like the implementation of macOS and
   6 // doesn't additional OS support
   7
   8 use crate::cell::Cell;
   9 use crate::ptr;
  10
  11 #[thread_local]
  12 static DTORS: Cell<*mut List> = Cell::new(ptr::null_mut());
  13
  14 type List = Vec<(*mut u8, unsafe extern "C" fn(*mut u8))>;
  15
  16 pub unsafe fn register_dtor(t: *mut u8, dtor: unsafe extern "C" fn(*mut u8)) {
  17     if DTORS.get().is_null() {
  18         let v: Box<List> = box Vec::new();
  19         DTORS.set(Box::into_raw(v));
  20     }
  21
  22     let list: &mut List = &mut *DTORS.get();
  23     list.push((t, dtor));
  24 }
  25
  26 // every thread call this function to run through all possible destructors
  27 pub unsafe fn run_dtors() {
  28     let mut ptr = DTORS.replace(ptr::null_mut());
  29     while !ptr.is_null() {
  30         let list = Box::from_raw(ptr);
  31         for (ptr, dtor) in list.into_iter() {
  32             dtor(ptr);
  33         }
  34         ptr = DTORS.replace(ptr::null_mut());
  35     }
  36 }