diff --git a/library/std/src/sys/thread_local/fast_local.rs b/library/std/src/sys/thread_local/fast_local.rs deleted file mode 100644 index 49b51a729e4..00000000000 --- a/library/std/src/sys/thread_local/fast_local.rs +++ /dev/null @@ -1,247 +0,0 @@ -use super::lazy::LazyKeyInner; -use crate::cell::Cell; -use crate::sys::thread_local_dtor::register_dtor; -use crate::{fmt, mem, panic, ptr}; - -#[doc(hidden)] -#[allow_internal_unstable(thread_local_internals, cfg_target_thread_local, thread_local)] -#[allow_internal_unsafe] -#[unstable(feature = "thread_local_internals", issue = "none")] -#[rustc_macro_transparency = "semitransparent"] -pub macro thread_local_inner { - // used to generate the `LocalKey` value for const-initialized thread locals - (@key $t:ty, const $init:expr) => {{ - #[inline] - #[deny(unsafe_op_in_unsafe_fn)] - unsafe fn __getit( - _init: $crate::option::Option<&mut $crate::option::Option<$t>>, - ) -> $crate::option::Option<&'static $t> { - const INIT_EXPR: $t = $init; - // If the platform has support for `#[thread_local]`, use it. - #[thread_local] - // We use `UnsafeCell` here instead of `static mut` to ensure any generated TLS shims - // have a nonnull attribute on their return value. - static VAL: $crate::cell::UnsafeCell<$t> = $crate::cell::UnsafeCell::new(INIT_EXPR); - - // If a dtor isn't needed we can do something "very raw" and - // just get going. - if !$crate::mem::needs_drop::<$t>() { - unsafe { - return $crate::option::Option::Some(&*VAL.get()) - } - } - - // 0 == dtor not registered - // 1 == dtor registered, dtor not run - // 2 == dtor registered and is running or has run - #[thread_local] - static STATE: $crate::cell::Cell<$crate::primitive::u8> = $crate::cell::Cell::new(0); - - // Safety: Performs `drop_in_place(ptr as *mut $t)`, and requires - // all that comes with it. - unsafe extern "C" fn destroy(ptr: *mut $crate::primitive::u8) { - $crate::thread::local_impl::abort_on_dtor_unwind(|| { - let old_state = STATE.replace(2); - $crate::debug_assert_eq!(old_state, 1); - // Safety: safety requirement is passed on to caller. - unsafe { $crate::ptr::drop_in_place(ptr.cast::<$t>()); } - }); - } - - unsafe { - match STATE.get() { - // 0 == we haven't registered a destructor, so do - // so now. - 0 => { - $crate::thread::local_impl::Key::<$t>::register_dtor( - VAL.get() as *mut $crate::primitive::u8, - destroy, - ); - STATE.set(1); - $crate::option::Option::Some(&*VAL.get()) - } - // 1 == the destructor is registered and the value - // is valid, so return the pointer. - 1 => $crate::option::Option::Some(&*VAL.get()), - // otherwise the destructor has already run, so we - // can't give access. - _ => $crate::option::Option::None, - } - } - } - - unsafe { - $crate::thread::LocalKey::new(__getit) - } - }}, - - // used to generate the `LocalKey` value for `thread_local!` - (@key $t:ty, $init:expr) => { - { - #[inline] - fn __init() -> $t { $init } - - #[inline] - unsafe fn __getit( - init: $crate::option::Option<&mut $crate::option::Option<$t>>, - ) -> $crate::option::Option<&'static $t> { - #[thread_local] - static __KEY: $crate::thread::local_impl::Key<$t> = - $crate::thread::local_impl::Key::<$t>::new(); - - unsafe { - __KEY.get(move || { - if let $crate::option::Option::Some(init) = init { - if let $crate::option::Option::Some(value) = init.take() { - return value; - } - if $crate::cfg!(debug_assertions) { - $crate::unreachable!("missing default value"); - } - } - __init() - }) - } - } - - unsafe { - $crate::thread::LocalKey::new(__getit) - } - } - }, - ($(#[$attr:meta])* $vis:vis $name:ident, $t:ty, $($init:tt)*) => { - $(#[$attr])* $vis const $name: $crate::thread::LocalKey<$t> = - $crate::thread::local_impl::thread_local_inner!(@key $t, $($init)*); - }, -} - -#[derive(Copy, Clone)] -enum DtorState { - Unregistered, - Registered, - RunningOrHasRun, -} - -// This data structure has been carefully constructed so that the fast path -// only contains one branch on x86. That optimization is necessary to avoid -// duplicated tls lookups on OSX. -// -// LLVM issue: https://bugs.llvm.org/show_bug.cgi?id=41722 -pub struct Key { - // If `LazyKeyInner::get` returns `None`, that indicates either: - // * The value has never been initialized - // * The value is being recursively initialized - // * The value has already been destroyed or is being destroyed - // To determine which kind of `None`, check `dtor_state`. - // - // This is very optimizer friendly for the fast path - initialized but - // not yet dropped. - inner: LazyKeyInner, - - // Metadata to keep track of the state of the destructor. Remember that - // this variable is thread-local, not global. - dtor_state: Cell, -} - -impl fmt::Debug for Key { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_struct("Key").finish_non_exhaustive() - } -} -impl Key { - pub const fn new() -> Key { - Key { inner: LazyKeyInner::new(), dtor_state: Cell::new(DtorState::Unregistered) } - } - - // note that this is just a publicly-callable function only for the - // const-initialized form of thread locals, basically a way to call the - // free `register_dtor` function defined elsewhere in std. - pub unsafe fn register_dtor(a: *mut u8, dtor: unsafe extern "C" fn(*mut u8)) { - unsafe { - register_dtor(a, dtor); - } - } - - pub unsafe fn get T>(&self, init: F) -> Option<&'static T> { - // SAFETY: See the definitions of `LazyKeyInner::get` and - // `try_initialize` for more information. - // - // The caller must ensure no mutable references are ever active to - // the inner cell or the inner T when this is called. - // The `try_initialize` is dependant on the passed `init` function - // for this. - unsafe { - match self.inner.get() { - Some(val) => Some(val), - None => self.try_initialize(init), - } - } - } - - // `try_initialize` is only called once per fast thread local variable, - // except in corner cases where thread_local dtors reference other - // thread_local's, or it is being recursively initialized. - // - // Macos: Inlining this function can cause two `tlv_get_addr` calls to - // be performed for every call to `Key::get`. - // LLVM issue: https://bugs.llvm.org/show_bug.cgi?id=41722 - #[inline(never)] - unsafe fn try_initialize T>(&self, init: F) -> Option<&'static T> { - // SAFETY: See comment above (this function doc). - if !mem::needs_drop::() || unsafe { self.try_register_dtor() } { - // SAFETY: See comment above (this function doc). - Some(unsafe { self.inner.initialize(init) }) - } else { - None - } - } - - // `try_register_dtor` is only called once per fast thread local - // variable, except in corner cases where thread_local dtors reference - // other thread_local's, or it is being recursively initialized. - unsafe fn try_register_dtor(&self) -> bool { - match self.dtor_state.get() { - DtorState::Unregistered => { - // SAFETY: dtor registration happens before initialization. - // Passing `self` as a pointer while using `destroy_value` - // is safe because the function will build a pointer to a - // Key, which is the type of self and so find the correct - // size. - unsafe { register_dtor(self as *const _ as *mut u8, destroy_value::) }; - self.dtor_state.set(DtorState::Registered); - true - } - DtorState::Registered => { - // recursively initialized - true - } - DtorState::RunningOrHasRun => false, - } - } -} - -unsafe extern "C" fn destroy_value(ptr: *mut u8) { - let ptr = ptr as *mut Key; - - // SAFETY: - // - // The pointer `ptr` has been built just above and comes from - // `try_register_dtor` where it is originally a Key coming from `self`, - // making it non-NUL and of the correct type. - // - // Right before we run the user destructor be sure to set the - // `Option` to `None`, and `dtor_state` to `RunningOrHasRun`. This - // causes future calls to `get` to run `try_initialize_drop` again, - // which will now fail, and return `None`. - // - // Wrap the call in a catch to ensure unwinding is caught in the event - // a panic takes place in a destructor. - if let Err(_) = panic::catch_unwind(panic::AssertUnwindSafe(|| unsafe { - let Key { inner, dtor_state } = &*ptr; - let value = inner.take(); - dtor_state.set(DtorState::RunningOrHasRun); - drop(value); - })) { - rtabort!("thread local panicked on drop"); - } -} diff --git a/library/std/src/sys/thread_local/fast_local/eager.rs b/library/std/src/sys/thread_local/fast_local/eager.rs new file mode 100644 index 00000000000..c2bc580530b --- /dev/null +++ b/library/std/src/sys/thread_local/fast_local/eager.rs @@ -0,0 +1,82 @@ +use crate::cell::{Cell, UnsafeCell}; +use crate::ptr::{self, drop_in_place}; +use crate::sys::thread_local::abort_on_dtor_unwind; +use crate::sys::thread_local_dtor::register_dtor; + +#[derive(Clone, Copy)] +enum State { + Initial, + Alive, + Destroyed, +} + +#[allow(missing_debug_implementations)] +pub struct Storage { + state: Cell, + val: UnsafeCell, +} + +impl Storage { + pub const fn new(val: T) -> Storage { + Storage { state: Cell::new(State::Initial), val: UnsafeCell::new(val) } + } + + /// Get a reference to the TLS value. If the TLS variable has been destroyed, + /// `None` is returned. + /// + /// # Safety + /// * The `self` reference must remain valid until the TLS destructor has been + /// run. + /// * The returned reference may only be used until thread destruction occurs + /// and may not be used after reentrant initialization has occurred. + /// + // FIXME(#110897): return NonNull instead of lying about the lifetime. + #[inline] + pub unsafe fn get(&self) -> Option<&'static T> { + match self.state.get() { + // SAFETY: as the state is not `Destroyed`, the value cannot have + // been destroyed yet. The reference fulfills the terms outlined + // above. + State::Alive => unsafe { Some(&*self.val.get()) }, + State::Destroyed => None, + State::Initial => unsafe { self.initialize() }, + } + } + + #[cold] + unsafe fn initialize(&self) -> Option<&'static T> { + // Register the destructor + + // SAFETY: + // * the destructor will be called at thread destruction. + // * the caller guarantees that `self` will be valid until that time. + unsafe { + register_dtor(ptr::from_ref(self).cast_mut().cast(), destroy::); + } + self.state.set(State::Alive); + // SAFETY: as the state is not `Destroyed`, the value cannot have + // been destroyed yet. The reference fulfills the terms outlined + // above. + unsafe { Some(&*self.val.get()) } + } +} + +/// Transition an `Alive` TLS variable into the `Destroyed` state, dropping its +/// value. +/// +/// # Safety +/// * Must only be called at thread destruction. +/// * `ptr` must point to an instance of `Storage` with `Alive` state and be +/// valid for accessing that instance. +unsafe extern "C" fn destroy(ptr: *mut u8) { + // Print a nice abort message if a panic occurs. + abort_on_dtor_unwind(|| { + let storage = unsafe { &*(ptr as *const Storage) }; + // Update the state before running the destructor as it may attempt to + // access the variable. + storage.state.set(State::Destroyed); + unsafe { + drop_in_place(storage.val.get()); + } + }) +} diff --git a/library/std/src/sys/thread_local/fast_local/lazy.rs b/library/std/src/sys/thread_local/fast_local/lazy.rs new file mode 100644 index 00000000000..14371768d30 --- /dev/null +++ b/library/std/src/sys/thread_local/fast_local/lazy.rs @@ -0,0 +1,122 @@ +use crate::cell::UnsafeCell; +use crate::hint::unreachable_unchecked; +use crate::mem::forget; +use crate::ptr; +use crate::sys::thread_local::abort_on_dtor_unwind; +use crate::sys::thread_local_dtor::register_dtor; + +pub unsafe trait DestroyedState: Sized { + fn register_dtor(s: &Storage); +} + +unsafe impl DestroyedState for ! { + fn register_dtor(_: &Storage) {} +} + +unsafe impl DestroyedState for () { + fn register_dtor(s: &Storage) { + unsafe { + register_dtor(ptr::from_ref(s).cast_mut().cast(), destroy::); + } + } +} + +enum State { + Initial, + Alive(T), + Destroyed(D), +} + +#[allow(missing_debug_implementations)] +pub struct Storage { + state: UnsafeCell>, +} + +impl Storage +where + D: DestroyedState, +{ + pub const fn new() -> Storage { + Storage { state: UnsafeCell::new(State::Initial) } + } + + /// Get a reference to the TLS value, potentially initializing it with the + /// provided parameters. If the TLS variable has been destroyed, `None` is + /// returned. + /// + /// # Safety + /// * The `self` reference must remain valid until the TLS destructor is run, + /// at which point the returned reference is invalidated. + /// * The returned reference may only be used until thread destruction occurs + /// and may not be used after reentrant initialization has occurred. + /// + // FIXME(#110897): return NonNull instead of lying about the lifetime. + #[inline] + pub unsafe fn get_or_init( + &self, + i: Option<&mut Option>, + f: impl FnOnce() -> T, + ) -> Option<&'static T> { + // SAFETY: + // No mutable reference to the inner value exists outside the calls to + // `replace`. The lifetime of the returned reference fulfills the terms + // outlined above. + let state = unsafe { &*self.state.get() }; + match state { + State::Alive(v) => Some(v), + State::Destroyed(_) => None, + State::Initial => unsafe { self.initialize(i, f) }, + } + } + + #[cold] + unsafe fn initialize( + &self, + i: Option<&mut Option>, + f: impl FnOnce() -> T, + ) -> Option<&'static T> { + // Perform initialization + + let v = i.and_then(Option::take).unwrap_or_else(f); + + // SAFETY: + // If references to the inner value exist, they were created in `f` + // and are invalidated here. The caller promises to never use them + // after this. + let old = unsafe { self.state.get().replace(State::Alive(v)) }; + match old { + // If the variable is not being recursively initialized, register + // the destructor. This might be a noop if the value does not need + // destruction. + State::Initial => D::register_dtor(self), + // Else, drop the old value. This might be changed to a panic. + val => drop(val), + } + + // SAFETY: + // Initialization was completed and the state was set to `Alive`, so the + // reference fulfills the terms outlined above. + unsafe { + let State::Alive(v) = &*self.state.get() else { unreachable_unchecked() }; + Some(v) + } + } +} + +/// Transition an `Alive` TLS variable into the `Destroyed` state, dropping its +/// value. +/// +/// # Safety +/// * Must only be called at thread destruction. +/// * `ptr` must point to an instance of `Storage` and be valid for +/// accessing that instance. +unsafe extern "C" fn destroy(ptr: *mut u8) { + // Print a nice abort message if a panic occurs. + abort_on_dtor_unwind(|| { + let storage = unsafe { &*(ptr as *const Storage) }; + // Update the state before running the destructor as it may attempt to + // access the variable. + let val = unsafe { storage.state.get().replace(State::Destroyed(())) }; + drop(val); + }) +} diff --git a/library/std/src/sys/thread_local/fast_local/mod.rs b/library/std/src/sys/thread_local/fast_local/mod.rs new file mode 100644 index 00000000000..25379071cb7 --- /dev/null +++ b/library/std/src/sys/thread_local/fast_local/mod.rs @@ -0,0 +1,122 @@ +//! Thread local support for platforms with native TLS. +//! +//! To achieve the best performance, we choose from four different types for +//! the TLS variable, depending from the method of initialization used (`const` +//! or lazy) and the drop requirements of the stored type: +//! +//! | | `Drop` | `!Drop` | +//! |--------:|:--------------------:|:-------------------:| +//! | `const` | `EagerStorage` | `T` | +//! | lazy | `LazyStorage` | `LazyStorage` | +//! +//! For `const` initialization and `!Drop` types, we simply use `T` directly, +//! but for other situations, we implement a state machine to handle +//! initialization of the variable and its destructor and destruction. +//! Upon accessing the TLS variable, the current state is compared: +//! +//! 1. If the state is `Initial`, initialize the storage, transition the state +//! to `Alive` and (if applicable) register the destructor, and return a +//! reference to the value. +//! 2. If the state is `Alive`, initialization was previously completed, so +//! return a reference to the value. +//! 3. If the state is `Destroyed`, the destructor has been run already, so +//! return [`None`]. +//! +//! The TLS destructor sets the state to `Destroyed` and drops the current value. +//! +//! To simplify the code, we make `LazyStorage` generic over the destroyed state +//! and use the `!` type (never type) as type parameter for `!Drop` types. This +//! eliminates the `Destroyed` state for these values, which can allow more niche +//! optimizations to occur for the `State` enum. For `Drop` types, `()` is used. + +#![deny(unsafe_op_in_unsafe_fn)] + +mod eager; +mod lazy; + +pub use eager::Storage as EagerStorage; +pub use lazy::Storage as LazyStorage; + +#[doc(hidden)] +#[allow_internal_unstable( + thread_local_internals, + cfg_target_thread_local, + thread_local, + never_type +)] +#[allow_internal_unsafe] +#[unstable(feature = "thread_local_internals", issue = "none")] +#[rustc_macro_transparency = "semitransparent"] +pub macro thread_local_inner { + // used to generate the `LocalKey` value for const-initialized thread locals + (@key $t:ty, const $init:expr) => {{ + const __INIT: $t = $init; + + #[inline] + #[deny(unsafe_op_in_unsafe_fn)] + unsafe fn __getit( + _init: $crate::option::Option<&mut $crate::option::Option<$t>>, + ) -> $crate::option::Option<&'static $t> { + use $crate::thread::local_impl::EagerStorage; + use $crate::mem::needs_drop; + use $crate::ptr::addr_of; + + if needs_drop::<$t>() { + #[thread_local] + static VAL: EagerStorage<$t> = EagerStorage::new(__INIT); + unsafe { + VAL.get() + } + } else { + #[thread_local] + static VAL: $t = __INIT; + unsafe { + $crate::option::Option::Some(&*addr_of!(VAL)) + } + } + } + + unsafe { + $crate::thread::LocalKey::new(__getit) + } + }}, + + // used to generate the `LocalKey` value for `thread_local!` + (@key $t:ty, $init:expr) => {{ + #[inline] + fn __init() -> $t { + $init + } + + #[inline] + #[deny(unsafe_op_in_unsafe_fn)] + unsafe fn __getit( + init: $crate::option::Option<&mut $crate::option::Option<$t>>, + ) -> $crate::option::Option<&'static $t> { + use $crate::thread::local_impl::LazyStorage; + use $crate::mem::needs_drop; + + if needs_drop::<$t>() { + #[thread_local] + static VAL: LazyStorage<$t, ()> = LazyStorage::new(); + unsafe { + VAL.get_or_init(init, __init) + } + } else { + #[thread_local] + static VAL: LazyStorage<$t, !> = LazyStorage::new(); + unsafe { + VAL.get_or_init(init, __init) + } + } + } + + unsafe { + $crate::thread::LocalKey::new(__getit) + } + }}, + ($(#[$attr:meta])* $vis:vis $name:ident, $t:ty, $($init:tt)*) => { + $(#[$attr])* $vis const $name: $crate::thread::LocalKey<$t> = + $crate::thread::local_impl::thread_local_inner!(@key $t, $($init)*); + }, +} diff --git a/library/std/src/sys/thread_local/mod.rs b/library/std/src/sys/thread_local/mod.rs index 7500c95d8b4..6298a5b71cc 100644 --- a/library/std/src/sys/thread_local/mod.rs +++ b/library/std/src/sys/thread_local/mod.rs @@ -15,7 +15,7 @@ cfg_if::cfg_if! { #[doc(hidden)] mod fast_local; #[doc(hidden)] - pub use fast_local::{Key, thread_local_inner}; + pub use fast_local::{EagerStorage, LazyStorage, thread_local_inner}; } else { #[doc(hidden)] mod os_local; @@ -24,6 +24,9 @@ cfg_if::cfg_if! { } } +// Not used by the fast-local TLS anymore. +// FIXME(#110897): remove this. +#[allow(unused)] mod lazy { use crate::cell::UnsafeCell; use crate::hint; diff --git a/library/std/src/thread/mod.rs b/library/std/src/thread/mod.rs index 78bc9af6c4d..22215873933 100644 --- a/library/std/src/thread/mod.rs +++ b/library/std/src/thread/mod.rs @@ -205,7 +205,7 @@ cfg_if::cfg_if! { #[doc(hidden)] #[unstable(feature = "thread_local_internals", issue = "none")] pub mod local_impl { - pub use crate::sys::thread_local::{thread_local_inner, Key, abort_on_dtor_unwind}; + pub use crate::sys::thread_local::*; } } } diff --git a/src/tools/tidy/src/issues.txt b/src/tools/tidy/src/issues.txt index 6b8106bbc21..881b4f84173 100644 --- a/src/tools/tidy/src/issues.txt +++ b/src/tools/tidy/src/issues.txt @@ -3988,8 +3988,6 @@ ui/test-attrs/issue-52557.rs ui/test-attrs/issue-53675-a-test-called-panic.rs ui/threads-sendsync/issue-24313.rs ui/threads-sendsync/issue-29488.rs -ui/threads-sendsync/issue-43733-2.rs -ui/threads-sendsync/issue-43733.rs ui/threads-sendsync/issue-4446.rs ui/threads-sendsync/issue-4448.rs ui/threads-sendsync/issue-8827.rs diff --git a/tests/ui/threads-sendsync/issue-43733-2.rs b/tests/ui/threads-sendsync/issue-43733-2.rs deleted file mode 100644 index 372ebf2cff9..00000000000 --- a/tests/ui/threads-sendsync/issue-43733-2.rs +++ /dev/null @@ -1,30 +0,0 @@ -//@ needs-threads -//@ dont-check-compiler-stderr -#![feature(cfg_target_thread_local, thread_local_internals)] - -// On platforms *without* `#[thread_local]`, use -// a custom non-`Sync` type to fake the same error. -#[cfg(not(target_thread_local))] -struct Key { - _data: std::cell::UnsafeCell>, - _flag: std::cell::Cell<()>, -} - -#[cfg(not(target_thread_local))] -impl Key { - const fn new() -> Self { - Key { - _data: std::cell::UnsafeCell::new(None), - _flag: std::cell::Cell::new(()), - } - } -} - -#[cfg(target_thread_local)] -use std::thread::local_impl::Key; - -static __KEY: Key<()> = Key::new(); -//~^ ERROR `UnsafeCell>` cannot be shared between threads -//~| ERROR cannot be shared between threads safely [E0277] - -fn main() {} diff --git a/tests/ui/threads-sendsync/issue-43733.rs b/tests/ui/threads-sendsync/issue-43733.rs deleted file mode 100644 index c90f60887cf..00000000000 --- a/tests/ui/threads-sendsync/issue-43733.rs +++ /dev/null @@ -1,32 +0,0 @@ -//@ needs-threads -#![feature(thread_local)] -#![feature(cfg_target_thread_local, thread_local_internals)] - -use std::cell::RefCell; - -type Foo = std::cell::RefCell; - -#[cfg(target_thread_local)] -#[thread_local] -static __KEY: std::thread::local_impl::Key = std::thread::local_impl::Key::new(); - -#[cfg(not(target_thread_local))] -static __KEY: std::thread::local_impl::Key = std::thread::local_impl::Key::new(); - -fn __getit(_: Option<&mut Option>>) -> std::option::Option<&'static Foo> { - __KEY.get(Default::default) - //~^ ERROR call to unsafe function `Key::::get` is unsafe -} - -static FOO: std::thread::LocalKey = std::thread::LocalKey::new(__getit); -//~^ ERROR call to unsafe function `LocalKey::::new` is unsafe - -fn main() { - FOO.with(|foo| println!("{}", foo.borrow())); - std::thread::spawn(|| { - FOO.with(|foo| *foo.borrow_mut() += "foo"); - }) - .join() - .unwrap(); - FOO.with(|foo| println!("{}", foo.borrow())); -} diff --git a/tests/ui/threads-sendsync/issue-43733.stderr b/tests/ui/threads-sendsync/issue-43733.stderr deleted file mode 100644 index 9b13646a228..00000000000 --- a/tests/ui/threads-sendsync/issue-43733.stderr +++ /dev/null @@ -1,19 +0,0 @@ -error[E0133]: call to unsafe function `Key::::get` is unsafe and requires unsafe function or block - --> $DIR/issue-43733.rs:17:5 - | -LL | __KEY.get(Default::default) - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ call to unsafe function - | - = note: consult the function's documentation for information on how to avoid undefined behavior - -error[E0133]: call to unsafe function `LocalKey::::new` is unsafe and requires unsafe function or block - --> $DIR/issue-43733.rs:21:42 - | -LL | static FOO: std::thread::LocalKey = std::thread::LocalKey::new(__getit); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ call to unsafe function - | - = note: consult the function's documentation for information on how to avoid undefined behavior - -error: aborting due to 2 previous errors - -For more information about this error, try `rustc --explain E0133`.