diff options
| -rw-r--r-- | library/std/src/sys/windows/thread_local_dtor.rs | 37 |
1 files changed, 36 insertions, 1 deletions
diff --git a/library/std/src/sys/windows/thread_local_dtor.rs b/library/std/src/sys/windows/thread_local_dtor.rs index 7be13bc4b2b..bf865e0fd72 100644 --- a/library/std/src/sys/windows/thread_local_dtor.rs +++ b/library/std/src/sys/windows/thread_local_dtor.rs @@ -1,4 +1,39 @@ +//! Implements thread-local destructors that are not associated with any +//! particular data. + #![unstable(feature = "thread_local_internals", issue = "none")] #![cfg(target_thread_local)] +use super::c; + +// 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)); +} + +// See windows/thread_local_keys.rs for an explanation of this callback function. +// The short version is that all the function pointers in the `.CRT$XL*` array +// will be called whenever a thread or process starts or ends. + +#[link_section = ".CRT$XLD"] +#[doc(hidden)] +#[used] +pub static TLS_CALLBACK: unsafe extern "system" fn(c::LPVOID, c::DWORD, c::LPVOID) = tls_callback; -pub use crate::sys_common::thread_local_dtor::register_dtor_fallback as register_dtor; +unsafe extern "system" fn tls_callback(_: c::LPVOID, reason: c::DWORD, _: c::LPVOID) { + if reason == c::DLL_THREAD_DETACH || reason == c::DLL_PROCESS_DETACH { + // 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.shrink_to_fit(); + } +} |