diff --git a/library/std/src/sys/windows/thread_local_dtor.rs b/library/std/src/sys/windows/thread_local_dtor.rs index 7be13bc4b2b..25d1c6e8e87 100644 --- a/library/std/src/sys/windows/thread_local_dtor.rs +++ b/library/std/src/sys/windows/thread_local_dtor.rs @@ -1,4 +1,28 @@ +//! Implements thread-local destructors that are not associated with any +//! particular data. + #![unstable(feature = "thread_local_internals", issue = "none")] #![cfg(target_thread_local)] -pub use crate::sys_common::thread_local_dtor::register_dtor_fallback as register_dtor; +// Using a per-thread list avoids the problems in synchronizing global state. +#[thread_local] +static mut DESTRUCTORS: Vec<(*mut u8, unsafe extern "C" fn(*mut u8))> = Vec::new(); + +pub unsafe fn register_dtor(t: *mut u8, dtor: unsafe extern "C" fn(*mut u8)) { + DESTRUCTORS.push((t, dtor)); +} + +/// Runs destructors. This should not be called until thread exit. +pub unsafe fn run_keyless_dtors() { + // Drop all the destructors. + // + // Note: While this is potentially an infinite loop, it *should* be + // the case that this loop always terminates because we provide the + // guarantee that a TLS key cannot be set after it is flagged for + // destruction. + while let Some((ptr, dtor)) = DESTRUCTORS.pop() { + (dtor)(ptr); + } + // We're done so free the memory. + DESTRUCTORS = Vec::new(); +} diff --git a/library/std/src/sys/windows/thread_local_key.rs b/library/std/src/sys/windows/thread_local_key.rs index 0bc51114665..ec670238e6f 100644 --- a/library/std/src/sys/windows/thread_local_key.rs +++ b/library/std/src/sys/windows/thread_local_key.rs @@ -196,6 +196,8 @@ unsafe fn register_dtor(key: Key, dtor: Dtor) { unsafe extern "system" fn on_tls_callback(h: c::LPVOID, dwReason: c::DWORD, pv: c::LPVOID) { if dwReason == c::DLL_THREAD_DETACH || dwReason == c::DLL_PROCESS_DETACH { run_dtors(); + #[cfg(target_thread_local)] + super::thread_local_dtor::run_keyless_dtors(); } // See comments above for what this is doing. Note that we don't need this