macro_rules! __thread_local_inner {
// used to generate the `LocalKey` value for const-initialized thread locals
(@key $t:ty, const $init:expr) => {{
- #[cfg_attr(not(all(windows, target_thread_local)), inline)] // see comments below
- #[cfg_attr(all(windows, target_thread_local), inline(never))]
+ #[cfg_attr(not(windows), inline)] // see comments below
#[deny(unsafe_op_in_unsafe_fn)]
unsafe fn __getit(
_init: $crate::option::Option<&mut $crate::option::Option<$t>>,
fn __init() -> $t { $init }
// When reading this function you might ask "why is this inlined
- // everywhere other than Windows?", and "why must it not be inlined
- // on Windows?" and these are very reasonable questions to ask.
- //
- // The short story is that Windows doesn't support referencing
- // `#[thread_local]` across DLL boundaries. The slightly longer
- // story is that each module (dll or exe) has its own separate set
- // of static thread locals, so if you try and reference a
- // `#[thread_local]` that comes from `crate1.dll` from within one of
- // `crate2.dll`'s functions, then it might give you a completely
- // different thread local than what you asked for (or it might just
- // crash).
+ // everywhere other than Windows?", and that's a very reasonable
+ // question to ask. The short story is that it segfaults rustc if
+ // this function is inlined. The longer story is that Windows looks
+ // to not support `extern` references to thread locals across DLL
+ // boundaries. This appears to at least not be supported in the ABI
+ // that LLVM implements.
//
// Because of this we never inline on Windows, but we do inline on
// other platforms (where external references to thread locals
// Cargo question kinda). This means that, unfortunately, Windows
// gets the pessimistic path for now where it's never inlined.
//
- // The issue of "should improve things on Windows" is #84933
- #[cfg_attr(not(all(windows, target_thread_local)), inline)]
- #[cfg_attr(all(windows, target_thread_local), inline(never))]
+ // The issue of "should enable on Windows sometimes" is #84933
+ #[cfg_attr(not(windows), inline)]
unsafe fn __getit(
init: $crate::option::Option<&mut $crate::option::Option<$t>>,
) -> $crate::option::Option<&'static $t> {