diff options
Diffstat (limited to 'library/std')
45 files changed, 1555 insertions, 319 deletions
diff --git a/library/std/Cargo.toml b/library/std/Cargo.toml index 29ab9be0e69..7bc52976500 100644 --- a/library/std/Cargo.toml +++ b/library/std/Cargo.toml @@ -18,7 +18,6 @@ cfg-if = { version = "1.0", features = ['rustc-dep-of-std'] } panic_unwind = { path = "../panic_unwind", optional = true } panic_abort = { path = "../panic_abort" } core = { path = "../core", public = true } -compiler_builtins = { path = "../compiler-builtins/compiler-builtins" } unwind = { path = "../unwind" } hashbrown = { version = "0.15", default-features = false, features = [ 'rustc-dep-of-std', diff --git a/library/std/src/fs.rs b/library/std/src/fs.rs index 72ad7c244ee..a220a3f56e9 100644 --- a/library/std/src/fs.rs +++ b/library/std/src/fs.rs @@ -814,7 +814,7 @@ impl File { /// /// If this file handle/descriptor, or a clone of it, already holds a lock, the exact behavior /// is unspecified and platform dependent, including the possibility that it will deadlock. - /// However, if this method returns `Ok(true)`, then it has acquired an exclusive lock. + /// However, if this method returns `Ok(())`, then it has acquired an exclusive lock. /// /// If the file is not open for writing, it is unspecified whether this function returns an error. /// @@ -879,7 +879,7 @@ impl File { /// /// If this file handle, or a clone of it, already holds a lock, the exact behavior is /// unspecified and platform dependent, including the possibility that it will deadlock. - /// However, if this method returns `Ok(true)`, then it has acquired a shared lock. + /// However, if this method returns `Ok(())`, then it has acquired a shared lock. /// /// The lock will be released when this file (along with any other file descriptors/handles /// duplicated or inherited from it) is closed, or if the [`unlock`] method is called. @@ -1111,6 +1111,11 @@ impl File { /// `futimes` on macOS before 10.13) and the `SetFileTime` function on Windows. Note that this /// [may change in the future][changes]. /// + /// On most platforms, including UNIX and Windows platforms, this function can also change the + /// timestamps of a directory. To get a `File` representing a directory in order to call + /// `set_times`, open the directory with `File::open` without attempting to obtain write + /// permission. + /// /// [changes]: io#platform-specific-behavior /// /// # Errors @@ -1128,7 +1133,7 @@ impl File { /// use std::fs::{self, File, FileTimes}; /// /// let src = fs::metadata("src")?; - /// let dest = File::options().write(true).open("dest")?; + /// let dest = File::open("dest")?; /// let times = FileTimes::new() /// .set_accessed(src.accessed()?) /// .set_modified(src.modified()?); diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs index 323742a75b0..0c537530647 100644 --- a/library/std/src/lib.rs +++ b/library/std/src/lib.rs @@ -294,6 +294,8 @@ #![feature(f128)] #![feature(ffi_const)] #![feature(formatting_options)] +#![feature(hash_map_internals)] +#![feature(hash_map_macro)] #![feature(if_let_guard)] #![feature(intra_doc_pointers)] #![feature(iter_advance_by)] @@ -319,18 +321,17 @@ #![feature(try_blocks)] #![feature(try_trait_v2)] #![feature(type_alias_impl_trait)] -#![feature(unsigned_signed_diff)] // tidy-alphabetical-end // // Library features (core): // tidy-alphabetical-start -#![feature(array_chunks)] #![feature(bstr)] #![feature(bstr_internals)] #![feature(char_internals)] #![feature(clone_to_uninit)] #![feature(core_intrinsics)] #![feature(core_io_borrowed_buf)] +#![feature(drop_guard)] #![feature(duration_constants)] #![feature(error_generic_member_access)] #![feature(error_iter)] diff --git a/library/std/src/macros.rs b/library/std/src/macros.rs index 25e2b7ea137..254570ae9c8 100644 --- a/library/std/src/macros.rs +++ b/library/std/src/macros.rs @@ -379,3 +379,77 @@ macro_rules! dbg { ($($crate::dbg!($val)),+,) }; } + +#[doc(hidden)] +#[macro_export] +#[allow_internal_unstable(hash_map_internals)] +#[unstable(feature = "hash_map_internals", issue = "none")] +macro_rules! repetition_utils { + (@count $($tokens:tt),*) => {{ + [$($crate::repetition_utils!(@replace $tokens => ())),*].len() + }}; + + (@replace $x:tt => $y:tt) => { $y } +} + +/// Creates a [`HashMap`] containing the arguments. +/// +/// `hash_map!` allows specifying the entries that make +/// up the [`HashMap`] where the key and value are separated by a `=>`. +/// +/// The entries are separated by commas with a trailing comma being allowed. +/// +/// It is semantically equivalent to using repeated [`HashMap::insert`] +/// on a newly created hashmap. +/// +/// `hash_map!` will attempt to avoid repeated reallocations by +/// using [`HashMap::with_capacity`]. +/// +/// # Examples +/// +/// ```rust +/// #![feature(hash_map_macro)] +/// +/// let map = hash_map! { +/// "key" => "value", +/// "key1" => "value1" +/// }; +/// +/// assert_eq!(map.get("key"), Some(&"value")); +/// assert_eq!(map.get("key1"), Some(&"value1")); +/// assert!(map.get("brrrrrrooooommm").is_none()); +/// ``` +/// +/// And with a trailing comma +/// +///```rust +/// #![feature(hash_map_macro)] +/// +/// let map = hash_map! { +/// "key" => "value", // notice the , +/// }; +/// +/// assert_eq!(map.get("key"), Some(&"value")); +/// ``` +/// +/// The key and value are moved into the HashMap. +/// +/// [`HashMap`]: crate::collections::HashMap +/// [`HashMap::insert`]: crate::collections::HashMap::insert +/// [`HashMap::with_capacity`]: crate::collections::HashMap::with_capacity +#[macro_export] +#[allow_internal_unstable(hash_map_internals)] +#[unstable(feature = "hash_map_macro", issue = "144032")] +macro_rules! hash_map { + () => {{ + $crate::collections::HashMap::new() + }}; + + ( $( $key:expr => $value:expr ),* $(,)? ) => {{ + let mut map = $crate::collections::HashMap::with_capacity( + const { $crate::repetition_utils!(@count $($key),*) } + ); + $( map.insert($key, $value); )* + map + }} +} diff --git a/library/std/src/num/f32.rs b/library/std/src/num/f32.rs index 2bff73add33..5dee68ad909 100644 --- a/library/std/src/num/f32.rs +++ b/library/std/src/num/f32.rs @@ -44,7 +44,7 @@ impl f32 { #[rustc_allow_incoherent_impl] #[must_use = "method returns a new number and does not mutate the original value"] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_const_stable(feature = "const_float_round_methods", since = "CURRENT_RUSTC_VERSION")] + #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")] #[inline] pub const fn floor(self) -> f32 { core::f32::math::floor(self) @@ -67,7 +67,7 @@ impl f32 { #[rustc_allow_incoherent_impl] #[must_use = "method returns a new number and does not mutate the original value"] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_const_stable(feature = "const_float_round_methods", since = "CURRENT_RUSTC_VERSION")] + #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")] #[inline] pub const fn ceil(self) -> f32 { core::f32::math::ceil(self) @@ -96,7 +96,7 @@ impl f32 { #[rustc_allow_incoherent_impl] #[must_use = "method returns a new number and does not mutate the original value"] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_const_stable(feature = "const_float_round_methods", since = "CURRENT_RUSTC_VERSION")] + #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")] #[inline] pub const fn round(self) -> f32 { core::f32::math::round(self) @@ -123,7 +123,7 @@ impl f32 { #[rustc_allow_incoherent_impl] #[must_use = "method returns a new number and does not mutate the original value"] #[stable(feature = "round_ties_even", since = "1.77.0")] - #[rustc_const_stable(feature = "const_float_round_methods", since = "CURRENT_RUSTC_VERSION")] + #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")] #[inline] pub const fn round_ties_even(self) -> f32 { core::f32::math::round_ties_even(self) @@ -149,7 +149,7 @@ impl f32 { #[rustc_allow_incoherent_impl] #[must_use = "method returns a new number and does not mutate the original value"] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_const_stable(feature = "const_float_round_methods", since = "CURRENT_RUSTC_VERSION")] + #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")] #[inline] pub const fn trunc(self) -> f32 { core::f32::math::trunc(self) @@ -173,7 +173,7 @@ impl f32 { #[rustc_allow_incoherent_impl] #[must_use = "method returns a new number and does not mutate the original value"] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_const_stable(feature = "const_float_round_methods", since = "CURRENT_RUSTC_VERSION")] + #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")] #[inline] pub const fn fract(self) -> f32 { core::f32::math::fract(self) diff --git a/library/std/src/num/f64.rs b/library/std/src/num/f64.rs index b71e319f407..3ec80f68bdb 100644 --- a/library/std/src/num/f64.rs +++ b/library/std/src/num/f64.rs @@ -44,7 +44,7 @@ impl f64 { #[rustc_allow_incoherent_impl] #[must_use = "method returns a new number and does not mutate the original value"] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_const_stable(feature = "const_float_round_methods", since = "CURRENT_RUSTC_VERSION")] + #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")] #[inline] pub const fn floor(self) -> f64 { core::f64::math::floor(self) @@ -67,7 +67,7 @@ impl f64 { #[rustc_allow_incoherent_impl] #[must_use = "method returns a new number and does not mutate the original value"] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_const_stable(feature = "const_float_round_methods", since = "CURRENT_RUSTC_VERSION")] + #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")] #[inline] pub const fn ceil(self) -> f64 { core::f64::math::ceil(self) @@ -96,7 +96,7 @@ impl f64 { #[rustc_allow_incoherent_impl] #[must_use = "method returns a new number and does not mutate the original value"] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_const_stable(feature = "const_float_round_methods", since = "CURRENT_RUSTC_VERSION")] + #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")] #[inline] pub const fn round(self) -> f64 { core::f64::math::round(self) @@ -123,7 +123,7 @@ impl f64 { #[rustc_allow_incoherent_impl] #[must_use = "method returns a new number and does not mutate the original value"] #[stable(feature = "round_ties_even", since = "1.77.0")] - #[rustc_const_stable(feature = "const_float_round_methods", since = "CURRENT_RUSTC_VERSION")] + #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")] #[inline] pub const fn round_ties_even(self) -> f64 { core::f64::math::round_ties_even(self) @@ -149,7 +149,7 @@ impl f64 { #[rustc_allow_incoherent_impl] #[must_use = "method returns a new number and does not mutate the original value"] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_const_stable(feature = "const_float_round_methods", since = "CURRENT_RUSTC_VERSION")] + #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")] #[inline] pub const fn trunc(self) -> f64 { core::f64::math::trunc(self) @@ -173,7 +173,7 @@ impl f64 { #[rustc_allow_incoherent_impl] #[must_use = "method returns a new number and does not mutate the original value"] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_const_stable(feature = "const_float_round_methods", since = "CURRENT_RUSTC_VERSION")] + #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")] #[inline] pub const fn fract(self) -> f64 { core::f64::math::fract(self) diff --git a/library/std/src/panic.rs b/library/std/src/panic.rs index 234fb284a59..cff4f20b5a8 100644 --- a/library/std/src/panic.rs +++ b/library/std/src/panic.rs @@ -108,8 +108,6 @@ impl<'a> PanicHookInfo<'a> { /// # Example /// /// ```should_panic - /// #![feature(panic_payload_as_str)] - /// /// std::panic::set_hook(Box::new(|panic_info| { /// if let Some(s) = panic_info.payload_as_str() { /// println!("panic occurred: {s:?}"); @@ -122,7 +120,7 @@ impl<'a> PanicHookInfo<'a> { /// ``` #[must_use] #[inline] - #[unstable(feature = "panic_payload_as_str", issue = "125175")] + #[stable(feature = "panic_payload_as_str", since = "CURRENT_RUSTC_VERSION")] pub fn payload_as_str(&self) -> Option<&str> { if let Some(s) = self.payload.downcast_ref::<&str>() { Some(s) @@ -388,7 +386,7 @@ pub fn catch_unwind<F: FnOnce() -> R + UnwindSafe, R>(f: F) -> Result<R> { /// ``` #[stable(feature = "resume_unwind", since = "1.9.0")] pub fn resume_unwind(payload: Box<dyn Any + Send>) -> ! { - panicking::rust_panic_without_hook(payload) + panicking::resume_unwind(payload) } /// Makes all future panics abort directly without running the panic hook or unwinding. diff --git a/library/std/src/panicking.rs b/library/std/src/panicking.rs index 7873049d20b..87a3fc80dfa 100644 --- a/library/std/src/panicking.rs +++ b/library/std/src/panicking.rs @@ -269,6 +269,7 @@ fn default_hook(info: &PanicHookInfo<'_>) { thread::with_current_name(|name| { let name = name.unwrap_or("<unnamed>"); + let tid = thread::current_os_id(); // Try to write the panic message to a buffer first to prevent other concurrent outputs // interleaving with it. @@ -277,7 +278,7 @@ fn default_hook(info: &PanicHookInfo<'_>) { let write_msg = |dst: &mut dyn crate::io::Write| { // We add a newline to ensure the panic message appears at the start of a line. - writeln!(dst, "\nthread '{name}' panicked at {location}:\n{msg}") + writeln!(dst, "\nthread '{name}' ({tid}) panicked at {location}:\n{msg}") }; if write_msg(&mut cursor).is_ok() { @@ -627,7 +628,7 @@ pub fn panicking() -> bool { /// Entry point of panics from the core crate (`panic_impl` lang item). #[cfg(not(any(test, doctest)))] #[panic_handler] -pub fn begin_panic_handler(info: &core::panic::PanicInfo<'_>) -> ! { +pub fn panic_handler(info: &core::panic::PanicInfo<'_>) -> ! { struct FormatStringPayload<'a> { inner: &'a core::panic::PanicMessage<'a>, string: Option<String>, @@ -696,14 +697,14 @@ pub fn begin_panic_handler(info: &core::panic::PanicInfo<'_>) -> ! { let msg = info.message(); crate::sys::backtrace::__rust_end_short_backtrace(move || { if let Some(s) = msg.as_str() { - rust_panic_with_hook( + panic_with_hook( &mut StaticStrPayload(s), loc, info.can_unwind(), info.force_no_backtrace(), ); } else { - rust_panic_with_hook( + panic_with_hook( &mut FormatStringPayload { inner: &msg, string: None }, loc, info.can_unwind(), @@ -767,7 +768,7 @@ pub const fn begin_panic<M: Any + Send>(msg: M) -> ! { let loc = Location::caller(); crate::sys::backtrace::__rust_end_short_backtrace(move || { - rust_panic_with_hook( + panic_with_hook( &mut Payload { inner: Some(msg) }, loc, /* can_unwind */ true, @@ -792,7 +793,7 @@ fn payload_as_str(payload: &dyn Any) -> &str { /// panics, panic hooks, and finally dispatching to the panic runtime to either /// abort or unwind. #[optimize(size)] -fn rust_panic_with_hook( +fn panic_with_hook( payload: &mut dyn PanicPayload, location: &Location<'_>, can_unwind: bool, @@ -861,7 +862,7 @@ fn rust_panic_with_hook( /// This is the entry point for `resume_unwind`. /// It just forwards the payload to the panic runtime. #[cfg_attr(feature = "panic_immediate_abort", inline)] -pub fn rust_panic_without_hook(payload: Box<dyn Any + Send>) -> ! { +pub fn resume_unwind(payload: Box<dyn Any + Send>) -> ! { panic_count::increase(false); struct RewrapBox(Box<dyn Any + Send>); @@ -885,8 +886,8 @@ pub fn rust_panic_without_hook(payload: Box<dyn Any + Send>) -> ! { rust_panic(&mut RewrapBox(payload)) } -/// An unmangled function (through `rustc_std_internal_symbol`) on which to slap -/// yer breakpoints. +/// A function with a fixed suffix (through `rustc_std_internal_symbol`) +/// on which to slap yer breakpoints. #[inline(never)] #[cfg_attr(not(test), rustc_std_internal_symbol)] #[cfg(not(feature = "panic_immediate_abort"))] diff --git a/library/std/src/path.rs b/library/std/src/path.rs index d9c34d4fa04..e7ba6936435 100644 --- a/library/std/src/path.rs +++ b/library/std/src/path.rs @@ -2683,6 +2683,8 @@ impl Path { /// /// assert_eq!("foo", Path::new("foo.rs").file_prefix().unwrap()); /// assert_eq!("foo", Path::new("foo.tar.gz").file_prefix().unwrap()); + /// assert_eq!(".config", Path::new(".config").file_prefix().unwrap()); + /// assert_eq!(".config", Path::new(".config.toml").file_prefix().unwrap()); /// ``` /// /// # See Also @@ -3259,8 +3261,8 @@ impl Path { /// /// # Examples /// - #[cfg_attr(unix, doc = "```no_run")] - #[cfg_attr(not(unix), doc = "```ignore")] + /// ```rust,no_run + /// # #[cfg(unix)] { /// use std::path::Path; /// use std::os::unix::fs::symlink; /// @@ -3268,6 +3270,7 @@ impl Path { /// symlink("/origin_does_not_exist/", link_path).unwrap(); /// assert_eq!(link_path.is_symlink(), true); /// assert_eq!(link_path.exists(), false); + /// # } /// ``` /// /// # See Also diff --git a/library/std/src/sync/lazy_lock.rs b/library/std/src/sync/lazy_lock.rs index eba849d16da..a40e29a772a 100644 --- a/library/std/src/sync/lazy_lock.rs +++ b/library/std/src/sync/lazy_lock.rs @@ -25,6 +25,22 @@ union Data<T, F> { /// /// [`LazyCell`]: crate::cell::LazyCell /// +/// # Poisoning +/// +/// If the initialization closure passed to [`LazyLock::new`] panics, the lock will be poisoned. +/// Once the lock is poisoned, any threads that attempt to access this lock (via a dereference +/// or via an explicit call to [`force()`]) will panic. +/// +/// This concept is similar to that of poisoning in the [`std::sync::poison`] module. A key +/// difference, however, is that poisoning in `LazyLock` is _unrecoverable_. All future accesses of +/// the lock from other threads will panic, whereas a type in [`std::sync::poison`] like +/// [`std::sync::poison::Mutex`] allows recovery via [`PoisonError::into_inner()`]. +/// +/// [`force()`]: LazyLock::force +/// [`std::sync::poison`]: crate::sync::poison +/// [`std::sync::poison::Mutex`]: crate::sync::poison::Mutex +/// [`PoisonError::into_inner()`]: crate::sync::poison::PoisonError::into_inner +/// /// # Examples /// /// Initialize static variables with `LazyLock`. @@ -102,6 +118,10 @@ impl<T, F: FnOnce() -> T> LazyLock<T, F> { /// /// Returns `Ok(value)` if `Lazy` is initialized and `Err(f)` otherwise. /// + /// # Panics + /// + /// Panics if the lock is poisoned. + /// /// # Examples /// /// ``` @@ -136,6 +156,15 @@ impl<T, F: FnOnce() -> T> LazyLock<T, F> { /// Forces the evaluation of this lazy value and returns a mutable reference to /// the result. /// + /// # Panics + /// + /// If the initialization closure panics (the one that is passed to the [`new()`] method), the + /// panic is propagated to the caller, and the lock becomes poisoned. This will cause all future + /// accesses of the lock (via [`force()`] or a dereference) to panic. + /// + /// [`new()`]: LazyLock::new + /// [`force()`]: LazyLock::force + /// /// # Examples /// /// ``` @@ -193,6 +222,15 @@ impl<T, F: FnOnce() -> T> LazyLock<T, F> { /// This method will block the calling thread if another initialization /// routine is currently running. /// + /// # Panics + /// + /// If the initialization closure panics (the one that is passed to the [`new()`] method), the + /// panic is propagated to the caller, and the lock becomes poisoned. This will cause all future + /// accesses of the lock (via [`force()`] or a dereference) to panic. + /// + /// [`new()`]: LazyLock::new + /// [`force()`]: LazyLock::force + /// /// # Examples /// /// ``` @@ -227,7 +265,8 @@ impl<T, F: FnOnce() -> T> LazyLock<T, F> { } impl<T, F> LazyLock<T, F> { - /// Returns a mutable reference to the value if initialized, or `None` if not. + /// Returns a mutable reference to the value if initialized. Otherwise (if uninitialized or + /// poisoned), returns `None`. /// /// # Examples /// @@ -256,7 +295,8 @@ impl<T, F> LazyLock<T, F> { } } - /// Returns a reference to the value if initialized, or `None` if not. + /// Returns a reference to the value if initialized. Otherwise (if uninitialized or poisoned), + /// returns `None`. /// /// # Examples /// @@ -307,6 +347,14 @@ impl<T, F: FnOnce() -> T> Deref for LazyLock<T, F> { /// This method will block the calling thread if another initialization /// routine is currently running. /// + /// # Panics + /// + /// If the initialization closure panics (the one that is passed to the [`new()`] method), the + /// panic is propagated to the caller, and the lock becomes poisoned. This will cause all future + /// accesses of the lock (via [`force()`] or a dereference) to panic. + /// + /// [`new()`]: LazyLock::new + /// [`force()`]: LazyLock::force #[inline] fn deref(&self) -> &T { LazyLock::force(self) @@ -315,6 +363,14 @@ impl<T, F: FnOnce() -> T> Deref for LazyLock<T, F> { #[stable(feature = "lazy_deref_mut", since = "1.89.0")] impl<T, F: FnOnce() -> T> DerefMut for LazyLock<T, F> { + /// # Panics + /// + /// If the initialization closure panics (the one that is passed to the [`new()`] method), the + /// panic is propagated to the caller, and the lock becomes poisoned. This will cause all future + /// accesses of the lock (via [`force()`] or a dereference) to panic. + /// + /// [`new()`]: LazyLock::new + /// [`force()`]: LazyLock::force #[inline] fn deref_mut(&mut self) -> &mut T { LazyLock::force_mut(self) diff --git a/library/std/src/sync/mod.rs b/library/std/src/sync/mod.rs index e67b4f6f22f..6ef3bf25cf6 100644 --- a/library/std/src/sync/mod.rs +++ b/library/std/src/sync/mod.rs @@ -225,6 +225,8 @@ pub use self::poison::{MappedMutexGuard, MappedRwLockReadGuard, MappedRwLockWrit pub mod mpmc; pub mod mpsc; +#[unstable(feature = "sync_nonpoison", issue = "134645")] +pub mod nonpoison; #[unstable(feature = "sync_poison_mod", issue = "134646")] pub mod poison; diff --git a/library/std/src/sync/nonpoison.rs b/library/std/src/sync/nonpoison.rs new file mode 100644 index 00000000000..2bbf226dc2c --- /dev/null +++ b/library/std/src/sync/nonpoison.rs @@ -0,0 +1,37 @@ +//! Non-poisoning synchronous locks. +//! +//! The difference from the locks in the [`poison`] module is that the locks in this module will not +//! become poisoned when a thread panics while holding a guard. +//! +//! [`poison`]: super::poison + +use crate::fmt; + +/// A type alias for the result of a nonblocking locking method. +#[unstable(feature = "sync_nonpoison", issue = "134645")] +pub type TryLockResult<Guard> = Result<Guard, WouldBlock>; + +/// A lock could not be acquired at this time because the operation would otherwise block. +#[unstable(feature = "sync_nonpoison", issue = "134645")] +pub struct WouldBlock; + +#[unstable(feature = "sync_nonpoison", issue = "134645")] +impl fmt::Debug for WouldBlock { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + "WouldBlock".fmt(f) + } +} + +#[unstable(feature = "sync_nonpoison", issue = "134645")] +impl fmt::Display for WouldBlock { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + "try_lock failed because the operation would block".fmt(f) + } +} + +#[unstable(feature = "mapped_lock_guards", issue = "117108")] +pub use self::mutex::MappedMutexGuard; +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +pub use self::mutex::{Mutex, MutexGuard}; + +mod mutex; diff --git a/library/std/src/sync/nonpoison/mutex.rs b/library/std/src/sync/nonpoison/mutex.rs new file mode 100644 index 00000000000..b6861c78f00 --- /dev/null +++ b/library/std/src/sync/nonpoison/mutex.rs @@ -0,0 +1,611 @@ +use crate::cell::UnsafeCell; +use crate::fmt; +use crate::marker::PhantomData; +use crate::mem::{self, ManuallyDrop}; +use crate::ops::{Deref, DerefMut}; +use crate::ptr::NonNull; +use crate::sync::nonpoison::{TryLockResult, WouldBlock}; +use crate::sys::sync as sys; + +/// A mutual exclusion primitive useful for protecting shared data that does not keep track of +/// lock poisoning. +/// +/// For more information about mutexes, check out the documentation for the poisoning variant of +/// this lock at [`poison::Mutex`]. +/// +/// [`poison::Mutex`]: crate::sync::poison::Mutex +/// +/// # Examples +/// +/// Note that this `Mutex` does **not** propagate threads that panic while holding the lock via +/// poisoning. If you need this functionality, see [`poison::Mutex`]. +/// +/// ``` +/// #![feature(nonpoison_mutex)] +/// +/// use std::thread; +/// use std::sync::{Arc, nonpoison::Mutex}; +/// +/// let mutex = Arc::new(Mutex::new(0u32)); +/// let mut handles = Vec::new(); +/// +/// for n in 0..10 { +/// let m = Arc::clone(&mutex); +/// let handle = thread::spawn(move || { +/// let mut guard = m.lock(); +/// *guard += 1; +/// panic!("panic from thread {n} {guard}") +/// }); +/// handles.push(handle); +/// } +/// +/// for h in handles { +/// let _ = h.join(); +/// } +/// +/// println!("Finished, locked {} times", mutex.lock()); +/// ``` +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +#[cfg_attr(not(test), rustc_diagnostic_item = "NonPoisonMutex")] +pub struct Mutex<T: ?Sized> { + inner: sys::Mutex, + data: UnsafeCell<T>, +} + +/// `T` must be `Send` for a [`Mutex`] to be `Send` because it is possible to acquire +/// the owned `T` from the `Mutex` via [`into_inner`]. +/// +/// [`into_inner`]: Mutex::into_inner +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +unsafe impl<T: ?Sized + Send> Send for Mutex<T> {} + +/// `T` must be `Send` for [`Mutex`] to be `Sync`. +/// This ensures that the protected data can be accessed safely from multiple threads +/// without causing data races or other unsafe behavior. +/// +/// [`Mutex<T>`] provides mutable access to `T` to one thread at a time. However, it's essential +/// for `T` to be `Send` because it's not safe for non-`Send` structures to be accessed in +/// this manner. For instance, consider [`Rc`], a non-atomic reference counted smart pointer, +/// which is not `Send`. With `Rc`, we can have multiple copies pointing to the same heap +/// allocation with a non-atomic reference count. If we were to use `Mutex<Rc<_>>`, it would +/// only protect one instance of `Rc` from shared access, leaving other copies vulnerable +/// to potential data races. +/// +/// Also note that it is not necessary for `T` to be `Sync` as `&T` is only made available +/// to one thread at a time if `T` is not `Sync`. +/// +/// [`Rc`]: crate::rc::Rc +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +unsafe impl<T: ?Sized + Send> Sync for Mutex<T> {} + +/// An RAII implementation of a "scoped lock" of a mutex. When this structure is +/// dropped (falls out of scope), the lock will be unlocked. +/// +/// The data protected by the mutex can be accessed through this guard via its +/// [`Deref`] and [`DerefMut`] implementations. +/// +/// This structure is created by the [`lock`] and [`try_lock`] methods on +/// [`Mutex`]. +/// +/// [`lock`]: Mutex::lock +/// [`try_lock`]: Mutex::try_lock +#[must_use = "if unused the Mutex will immediately unlock"] +#[must_not_suspend = "holding a MutexGuard across suspend \ + points can cause deadlocks, delays, \ + and cause Futures to not implement `Send`"] +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +#[clippy::has_significant_drop] +#[cfg_attr(not(test), rustc_diagnostic_item = "NonPoisonMutexGuard")] +pub struct MutexGuard<'a, T: ?Sized + 'a> { + lock: &'a Mutex<T>, +} + +/// A [`MutexGuard`] is not `Send` to maximize platform portablity. +/// +/// On platforms that use POSIX threads (commonly referred to as pthreads) there is a requirement to +/// release mutex locks on the same thread they were acquired. +/// For this reason, [`MutexGuard`] must not implement `Send` to prevent it being dropped from +/// another thread. +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +impl<T: ?Sized> !Send for MutexGuard<'_, T> {} + +/// `T` must be `Sync` for a [`MutexGuard<T>`] to be `Sync` +/// because it is possible to get a `&T` from `&MutexGuard` (via `Deref`). +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +unsafe impl<T: ?Sized + Sync> Sync for MutexGuard<'_, T> {} + +// FIXME(nonpoison_condvar): Use this link instead: [`Condvar`]: crate::sync::nonpoison::Condvar +/// An RAII mutex guard returned by `MutexGuard::map`, which can point to a +/// subfield of the protected data. When this structure is dropped (falls out +/// of scope), the lock will be unlocked. +/// +/// The main difference between `MappedMutexGuard` and [`MutexGuard`] is that the +/// former cannot be used with [`Condvar`], since that could introduce soundness issues if the +/// locked object is modified by another thread while the `Mutex` is unlocked. +/// +/// The data protected by the mutex can be accessed through this guard via its +/// [`Deref`] and [`DerefMut`] implementations. +/// +/// This structure is created by the [`map`] and [`filter_map`] methods on +/// [`MutexGuard`]. +/// +/// [`map`]: MutexGuard::map +/// [`filter_map`]: MutexGuard::filter_map +/// [`Condvar`]: crate::sync::Condvar +#[must_use = "if unused the Mutex will immediately unlock"] +#[must_not_suspend = "holding a MappedMutexGuard across suspend \ + points can cause deadlocks, delays, \ + and cause Futures to not implement `Send`"] +#[unstable(feature = "mapped_lock_guards", issue = "117108")] +// #[unstable(feature = "nonpoison_mutex", issue = "134645")] +#[clippy::has_significant_drop] +pub struct MappedMutexGuard<'a, T: ?Sized + 'a> { + // NB: we use a pointer instead of `&'a mut T` to avoid `noalias` violations, because a + // `MappedMutexGuard` argument doesn't hold uniqueness for its whole scope, only until it drops. + // `NonNull` is covariant over `T`, so we add a `PhantomData<&'a mut T>` field + // below for the correct variance over `T` (invariance). + data: NonNull<T>, + inner: &'a sys::Mutex, + _variance: PhantomData<&'a mut T>, +} + +#[unstable(feature = "mapped_lock_guards", issue = "117108")] +// #[unstable(feature = "nonpoison_mutex", issue = "134645")] +impl<T: ?Sized> !Send for MappedMutexGuard<'_, T> {} +#[unstable(feature = "mapped_lock_guards", issue = "117108")] +// #[unstable(feature = "nonpoison_mutex", issue = "134645")] +unsafe impl<T: ?Sized + Sync> Sync for MappedMutexGuard<'_, T> {} + +impl<T> Mutex<T> { + /// Creates a new mutex in an unlocked state ready for use. + /// + /// # Examples + /// + /// ``` + /// #![feature(nonpoison_mutex)] + /// + /// use std::sync::nonpoison::Mutex; + /// + /// let mutex = Mutex::new(0); + /// ``` + #[unstable(feature = "nonpoison_mutex", issue = "134645")] + #[inline] + pub const fn new(t: T) -> Mutex<T> { + Mutex { inner: sys::Mutex::new(), data: UnsafeCell::new(t) } + } + + /// Returns the contained value by cloning it. + /// + /// # Examples + /// + /// ``` + /// #![feature(nonpoison_mutex)] + /// #![feature(lock_value_accessors)] + /// + /// use std::sync::nonpoison::Mutex; + /// + /// let mut mutex = Mutex::new(7); + /// + /// assert_eq!(mutex.get_cloned(), 7); + /// ``` + #[unstable(feature = "lock_value_accessors", issue = "133407")] + // #[unstable(feature = "nonpoison_mutex", issue = "134645")] + pub fn get_cloned(&self) -> T + where + T: Clone, + { + self.lock().clone() + } + + /// Sets the contained value. + /// + /// # Examples + /// + /// ``` + /// #![feature(nonpoison_mutex)] + /// #![feature(lock_value_accessors)] + /// + /// use std::sync::nonpoison::Mutex; + /// + /// let mut mutex = Mutex::new(7); + /// + /// assert_eq!(mutex.get_cloned(), 7); + /// mutex.set(11); + /// assert_eq!(mutex.get_cloned(), 11); + /// ``` + #[unstable(feature = "lock_value_accessors", issue = "133407")] + // #[unstable(feature = "nonpoison_mutex", issue = "134645")] + pub fn set(&self, value: T) { + if mem::needs_drop::<T>() { + // If the contained value has a non-trivial destructor, we + // call that destructor after the lock has been released. + drop(self.replace(value)) + } else { + *self.lock() = value; + } + } + + /// Replaces the contained value with `value`, and returns the old contained value. + /// + /// # Examples + /// + /// ``` + /// #![feature(nonpoison_mutex)] + /// #![feature(lock_value_accessors)] + /// + /// use std::sync::nonpoison::Mutex; + /// + /// let mut mutex = Mutex::new(7); + /// + /// assert_eq!(mutex.replace(11), 7); + /// assert_eq!(mutex.get_cloned(), 11); + /// ``` + #[unstable(feature = "lock_value_accessors", issue = "133407")] + // #[unstable(feature = "nonpoison_mutex", issue = "134645")] + pub fn replace(&self, value: T) -> T { + let mut guard = self.lock(); + mem::replace(&mut *guard, value) + } +} + +impl<T: ?Sized> Mutex<T> { + /// Acquires a mutex, blocking the current thread until it is able to do so. + /// + /// This function will block the local thread until it is available to acquire + /// the mutex. Upon returning, the thread is the only thread with the lock + /// held. An RAII guard is returned to allow scoped unlock of the lock. When + /// the guard goes out of scope, the mutex will be unlocked. + /// + /// The exact behavior on locking a mutex in the thread which already holds + /// the lock is left unspecified. However, this function will not return on + /// the second call (it might panic or deadlock, for example). + /// + /// # Panics + /// + /// This function might panic when called if the lock is already held by + /// the current thread. + /// + /// # Examples + /// + /// ``` + /// #![feature(nonpoison_mutex)] + /// + /// use std::sync::{Arc, nonpoison::Mutex}; + /// use std::thread; + /// + /// let mutex = Arc::new(Mutex::new(0)); + /// let c_mutex = Arc::clone(&mutex); + /// + /// thread::spawn(move || { + /// *c_mutex.lock() = 10; + /// }).join().expect("thread::spawn failed"); + /// assert_eq!(*mutex.lock(), 10); + /// ``` + #[unstable(feature = "nonpoison_mutex", issue = "134645")] + pub fn lock(&self) -> MutexGuard<'_, T> { + unsafe { + self.inner.lock(); + MutexGuard::new(self) + } + } + + /// Attempts to acquire this lock. + /// + /// This function does not block. If the lock could not be acquired at this time, then + /// [`WouldBlock`] is returned. Otherwise, an RAII guard is returned. + /// + /// The lock will be unlocked when the guard is dropped. + /// + /// # Errors + /// + /// If the mutex could not be acquired because it is already locked, then this call will return + /// the [`WouldBlock`] error. + /// + /// # Examples + /// + /// ``` + /// use std::sync::{Arc, Mutex}; + /// use std::thread; + /// + /// let mutex = Arc::new(Mutex::new(0)); + /// let c_mutex = Arc::clone(&mutex); + /// + /// thread::spawn(move || { + /// let mut lock = c_mutex.try_lock(); + /// if let Ok(ref mut mutex) = lock { + /// **mutex = 10; + /// } else { + /// println!("try_lock failed"); + /// } + /// }).join().expect("thread::spawn failed"); + /// assert_eq!(*mutex.lock().unwrap(), 10); + /// ``` + #[unstable(feature = "nonpoison_mutex", issue = "134645")] + pub fn try_lock(&self) -> TryLockResult<MutexGuard<'_, T>> { + unsafe { if self.inner.try_lock() { Ok(MutexGuard::new(self)) } else { Err(WouldBlock) } } + } + + /// Consumes this mutex, returning the underlying data. + /// + /// # Examples + /// + /// ``` + /// #![feature(nonpoison_mutex)] + /// + /// use std::sync::nonpoison::Mutex; + /// + /// let mutex = Mutex::new(0); + /// assert_eq!(mutex.into_inner(), 0); + /// ``` + #[unstable(feature = "nonpoison_mutex", issue = "134645")] + pub fn into_inner(self) -> T + where + T: Sized, + { + self.data.into_inner() + } + + /// Returns a mutable reference to the underlying data. + /// + /// Since this call borrows the `Mutex` mutably, no actual locking needs to + /// take place -- the mutable borrow statically guarantees no locks exist. + /// + /// # Examples + /// + /// ``` + /// #![feature(nonpoison_mutex)] + /// + /// use std::sync::nonpoison::Mutex; + /// + /// let mut mutex = Mutex::new(0); + /// *mutex.get_mut() = 10; + /// assert_eq!(*mutex.lock(), 10); + /// ``` + #[unstable(feature = "nonpoison_mutex", issue = "134645")] + pub fn get_mut(&mut self) -> &mut T { + self.data.get_mut() + } + + /// Returns a raw pointer to the underlying data. + /// + /// The returned pointer is always non-null and properly aligned, but it is + /// the user's responsibility to ensure that any reads and writes through it + /// are properly synchronized to avoid data races, and that it is not read + /// or written through after the mutex is dropped. + #[unstable(feature = "mutex_data_ptr", issue = "140368")] + // #[unstable(feature = "nonpoison_mutex", issue = "134645")] + pub fn data_ptr(&self) -> *mut T { + self.data.get() + } +} + +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +impl<T> From<T> for Mutex<T> { + /// Creates a new mutex in an unlocked state ready for use. + /// This is equivalent to [`Mutex::new`]. + fn from(t: T) -> Self { + Mutex::new(t) + } +} + +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +impl<T: ?Sized + Default> Default for Mutex<T> { + /// Creates a `Mutex<T>`, with the `Default` value for T. + fn default() -> Mutex<T> { + Mutex::new(Default::default()) + } +} + +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +impl<T: ?Sized + fmt::Debug> fmt::Debug for Mutex<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + let mut d = f.debug_struct("Mutex"); + match self.try_lock() { + Ok(guard) => { + d.field("data", &&*guard); + } + Err(WouldBlock) => { + d.field("data", &"<locked>"); + } + } + d.finish_non_exhaustive() + } +} + +impl<'mutex, T: ?Sized> MutexGuard<'mutex, T> { + unsafe fn new(lock: &'mutex Mutex<T>) -> MutexGuard<'mutex, T> { + return MutexGuard { lock }; + } +} + +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +impl<T: ?Sized> Deref for MutexGuard<'_, T> { + type Target = T; + + fn deref(&self) -> &T { + unsafe { &*self.lock.data.get() } + } +} + +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +impl<T: ?Sized> DerefMut for MutexGuard<'_, T> { + fn deref_mut(&mut self) -> &mut T { + unsafe { &mut *self.lock.data.get() } + } +} + +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +impl<T: ?Sized> Drop for MutexGuard<'_, T> { + #[inline] + fn drop(&mut self) { + unsafe { + self.lock.inner.unlock(); + } + } +} + +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +impl<T: ?Sized + fmt::Debug> fmt::Debug for MutexGuard<'_, T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::Debug::fmt(&**self, f) + } +} + +#[unstable(feature = "nonpoison_mutex", issue = "134645")] +impl<T: ?Sized + fmt::Display> fmt::Display for MutexGuard<'_, T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + (**self).fmt(f) + } +} + +impl<'a, T: ?Sized> MutexGuard<'a, T> { + /// Makes a [`MappedMutexGuard`] for a component of the borrowed data, e.g. + /// an enum variant. + /// + /// The `Mutex` is already locked, so this cannot fail. + /// + /// This is an associated function that needs to be used as + /// `MutexGuard::map(...)`. A method would interfere with methods of the + /// same name on the contents of the `MutexGuard` used through `Deref`. + #[unstable(feature = "mapped_lock_guards", issue = "117108")] + // #[unstable(feature = "nonpoison_mutex", issue = "134645")] + pub fn map<U, F>(orig: Self, f: F) -> MappedMutexGuard<'a, U> + where + F: FnOnce(&mut T) -> &mut U, + U: ?Sized, + { + // SAFETY: the conditions of `MutexGuard::new` were satisfied when the original guard + // was created, and have been upheld throughout `map` and/or `filter_map`. + // The signature of the closure guarantees that it will not "leak" the lifetime of the reference + // passed to it. If the closure panics, the guard will be dropped. + let data = NonNull::from(f(unsafe { &mut *orig.lock.data.get() })); + let orig = ManuallyDrop::new(orig); + MappedMutexGuard { data, inner: &orig.lock.inner, _variance: PhantomData } + } + + /// Makes a [`MappedMutexGuard`] for a component of the borrowed data. The + /// original guard is returned as an `Err(...)` if the closure returns + /// `None`. + /// + /// The `Mutex` is already locked, so this cannot fail. + /// + /// This is an associated function that needs to be used as + /// `MutexGuard::filter_map(...)`. A method would interfere with methods of the + /// same name on the contents of the `MutexGuard` used through `Deref`. + #[unstable(feature = "mapped_lock_guards", issue = "117108")] + // #[unstable(feature = "nonpoison_mutex", issue = "134645")] + pub fn filter_map<U, F>(orig: Self, f: F) -> Result<MappedMutexGuard<'a, U>, Self> + where + F: FnOnce(&mut T) -> Option<&mut U>, + U: ?Sized, + { + // SAFETY: the conditions of `MutexGuard::new` were satisfied when the original guard + // was created, and have been upheld throughout `map` and/or `filter_map`. + // The signature of the closure guarantees that it will not "leak" the lifetime of the reference + // passed to it. If the closure panics, the guard will be dropped. + match f(unsafe { &mut *orig.lock.data.get() }) { + Some(data) => { + let data = NonNull::from(data); + let orig = ManuallyDrop::new(orig); + Ok(MappedMutexGuard { data, inner: &orig.lock.inner, _variance: PhantomData }) + } + None => Err(orig), + } + } +} + +#[unstable(feature = "mapped_lock_guards", issue = "117108")] +impl<T: ?Sized> Deref for MappedMutexGuard<'_, T> { + type Target = T; + + fn deref(&self) -> &T { + unsafe { self.data.as_ref() } + } +} + +#[unstable(feature = "mapped_lock_guards", issue = "117108")] +impl<T: ?Sized> DerefMut for MappedMutexGuard<'_, T> { + fn deref_mut(&mut self) -> &mut T { + unsafe { self.data.as_mut() } + } +} + +#[unstable(feature = "mapped_lock_guards", issue = "117108")] +impl<T: ?Sized> Drop for MappedMutexGuard<'_, T> { + #[inline] + fn drop(&mut self) { + unsafe { + self.inner.unlock(); + } + } +} + +#[unstable(feature = "mapped_lock_guards", issue = "117108")] +impl<T: ?Sized + fmt::Debug> fmt::Debug for MappedMutexGuard<'_, T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::Debug::fmt(&**self, f) + } +} + +#[unstable(feature = "mapped_lock_guards", issue = "117108")] +impl<T: ?Sized + fmt::Display> fmt::Display for MappedMutexGuard<'_, T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + (**self).fmt(f) + } +} + +impl<'a, T: ?Sized> MappedMutexGuard<'a, T> { + /// Makes a [`MappedMutexGuard`] for a component of the borrowed data, e.g. + /// an enum variant. + /// + /// The `Mutex` is already locked, so this cannot fail. + /// + /// This is an associated function that needs to be used as + /// `MappedMutexGuard::map(...)`. A method would interfere with methods of the + /// same name on the contents of the `MutexGuard` used through `Deref`. + #[unstable(feature = "mapped_lock_guards", issue = "117108")] + // #[unstable(feature = "nonpoison_mutex", issue = "134645")] + pub fn map<U, F>(mut orig: Self, f: F) -> MappedMutexGuard<'a, U> + where + F: FnOnce(&mut T) -> &mut U, + U: ?Sized, + { + // SAFETY: the conditions of `MutexGuard::new` were satisfied when the original guard + // was created, and have been upheld throughout `map` and/or `filter_map`. + // The signature of the closure guarantees that it will not "leak" the lifetime of the reference + // passed to it. If the closure panics, the guard will be dropped. + let data = NonNull::from(f(unsafe { orig.data.as_mut() })); + let orig = ManuallyDrop::new(orig); + MappedMutexGuard { data, inner: orig.inner, _variance: PhantomData } + } + + /// Makes a [`MappedMutexGuard`] for a component of the borrowed data. The + /// original guard is returned as an `Err(...)` if the closure returns + /// `None`. + /// + /// The `Mutex` is already locked, so this cannot fail. + /// + /// This is an associated function that needs to be used as + /// `MappedMutexGuard::filter_map(...)`. A method would interfere with methods of the + /// same name on the contents of the `MutexGuard` used through `Deref`. + #[unstable(feature = "mapped_lock_guards", issue = "117108")] + // #[unstable(feature = "nonpoison_mutex", issue = "134645")] + pub fn filter_map<U, F>(mut orig: Self, f: F) -> Result<MappedMutexGuard<'a, U>, Self> + where + F: FnOnce(&mut T) -> Option<&mut U>, + U: ?Sized, + { + // SAFETY: the conditions of `MutexGuard::new` were satisfied when the original guard + // was created, and have been upheld throughout `map` and/or `filter_map`. + // The signature of the closure guarantees that it will not "leak" the lifetime of the reference + // passed to it. If the closure panics, the guard will be dropped. + match f(unsafe { orig.data.as_mut() }) { + Some(data) => { + let data = NonNull::from(data); + let orig = ManuallyDrop::new(orig); + Ok(MappedMutexGuard { data, inner: orig.inner, _variance: PhantomData }) + } + None => Err(orig), + } + } +} diff --git a/library/std/src/sync/once_lock.rs b/library/std/src/sync/once_lock.rs index a5c3a6c46a4..b224044cbe0 100644 --- a/library/std/src/sync/once_lock.rs +++ b/library/std/src/sync/once_lock.rs @@ -16,6 +16,8 @@ use crate::sync::Once; /// A `OnceLock` can be thought of as a safe abstraction over uninitialized data that becomes /// initialized once written. /// +/// Unlike [`Mutex`](crate::sync::Mutex), `OnceLock` is never poisoned on panic. +/// /// [`OnceCell`]: crate::cell::OnceCell /// [`LazyLock<T, F>`]: crate::sync::LazyLock /// [`LazyLock::new(|| ...)`]: crate::sync::LazyLock::new diff --git a/library/std/src/sync/poison.rs b/library/std/src/sync/poison.rs index 0c05f152ef8..31889dcc10f 100644 --- a/library/std/src/sync/poison.rs +++ b/library/std/src/sync/poison.rs @@ -2,18 +2,21 @@ //! //! # Poisoning //! -//! All synchronization objects in this module implement a strategy called "poisoning" -//! where if a thread panics while holding the exclusive access granted by the primitive, -//! the state of the primitive is set to "poisoned". -//! This information is then propagated to all other threads +//! All synchronization objects in this module implement a strategy called +//! "poisoning" where a primitive becomes poisoned if it recognizes that some +//! thread has panicked while holding the exclusive access granted by the +//! primitive. This information is then propagated to all other threads //! to signify that the data protected by this primitive is likely tainted //! (some invariant is not being upheld). //! -//! The specifics of how this "poisoned" state affects other threads -//! depend on the primitive. See [#Overview] below. +//! The specifics of how this "poisoned" state affects other threads and whether +//! the panics are recognized reliably or on a best-effort basis depend on the +//! primitive. See [Overview](#overview) below. //! //! For the alternative implementations that do not employ poisoning, -//! see `std::sync::nonpoisoning`. +//! see [`std::sync::nonpoison`]. +//! +//! [`std::sync::nonpoison`]: crate::sync::nonpoison //! //! # Overview //! @@ -34,14 +37,15 @@ //! - [`Mutex`]: Mutual Exclusion mechanism, which ensures that at //! most one thread at a time is able to access some data. //! -//! [`Mutex::lock()`] returns a [`LockResult`], -//! providing a way to deal with the poisoned state. -//! See [`Mutex`'s documentation](Mutex#poisoning) for more. +//! Panicking while holding the lock typically poisons the mutex, but it is +//! not guaranteed to detect this condition in all circumstances. +//! [`Mutex::lock()`] returns a [`LockResult`], providing a way to deal with +//! the poisoned state. See [`Mutex`'s documentation](Mutex#poisoning) for more. //! //! - [`Once`]: A thread-safe way to run a piece of code only once. //! Mostly useful for implementing one-time global initialization. //! -//! [`Once`] is poisoned if the piece of code passed to +//! [`Once`] is reliably poisoned if the piece of code passed to //! [`Once::call_once()`] or [`Once::call_once_force()`] panics. //! When in poisoned state, subsequent calls to [`Once::call_once()`] will panic too. //! [`Once::call_once_force()`] can be used to clear the poisoned state. @@ -51,13 +55,11 @@ //! writer at a time. In some cases, this can be more efficient than //! a mutex. //! -//! This implementation, like [`Mutex`], will become poisoned on a panic. +//! This implementation, like [`Mutex`], usually becomes poisoned on a panic. //! Note, however, that an `RwLock` may only be poisoned if a panic occurs //! while it is locked exclusively (write mode). If a panic occurs in any reader, //! then the lock will not be poisoned. -// FIXME(sync_nonpoison) add links to sync::nonpoison to the doc comment above. - #[stable(feature = "rust1", since = "1.0.0")] pub use self::condvar::{Condvar, WaitTimeoutResult}; #[unstable(feature = "mapped_lock_guards", issue = "117108")] diff --git a/library/std/src/sync/poison/condvar.rs b/library/std/src/sync/poison/condvar.rs index 7f0f3f652bc..0e9d4233c65 100644 --- a/library/std/src/sync/poison/condvar.rs +++ b/library/std/src/sync/poison/condvar.rs @@ -13,7 +13,7 @@ use crate::time::{Duration, Instant}; #[stable(feature = "wait_timeout", since = "1.5.0")] pub struct WaitTimeoutResult(bool); -// FIXME(sync_nonpoison): `WaitTimeoutResult` is actually poisoning-agnostic, it seems. +// FIXME(nonpoison_condvar): `WaitTimeoutResult` is actually poisoning-agnostic, it seems. // Should we take advantage of this fact? impl WaitTimeoutResult { /// Returns `true` if the wait was known to have timed out. diff --git a/library/std/src/sync/poison/mutex.rs b/library/std/src/sync/poison/mutex.rs index 30325be685c..6205c4fa4ca 100644 --- a/library/std/src/sync/poison/mutex.rs +++ b/library/std/src/sync/poison/mutex.rs @@ -18,20 +18,69 @@ use crate::sys::sync as sys; /// # Poisoning /// /// The mutexes in this module implement a strategy called "poisoning" where a -/// mutex is considered poisoned whenever a thread panics while holding the -/// mutex. Once a mutex is poisoned, all other threads are unable to access the -/// data by default as it is likely tainted (some invariant is not being -/// upheld). +/// mutex becomes poisoned if it recognizes that the thread holding it has +/// panicked. /// -/// For a mutex, this means that the [`lock`] and [`try_lock`] methods return a +/// Once a mutex is poisoned, all other threads are unable to access the data by +/// default as it is likely tainted (some invariant is not being upheld). For a +/// mutex, this means that the [`lock`] and [`try_lock`] methods return a /// [`Result`] which indicates whether a mutex has been poisoned or not. Most /// usage of a mutex will simply [`unwrap()`] these results, propagating panics /// among threads to ensure that a possibly invalid invariant is not witnessed. /// -/// A poisoned mutex, however, does not prevent all access to the underlying -/// data. The [`PoisonError`] type has an [`into_inner`] method which will return -/// the guard that would have otherwise been returned on a successful lock. This -/// allows access to the data, despite the lock being poisoned. +/// Poisoning is only advisory: the [`PoisonError`] type has an [`into_inner`] +/// method which will return the guard that would have otherwise been returned +/// on a successful lock. This allows access to the data, despite the lock being +/// poisoned. +/// +/// In addition, the panic detection is not ideal, so even unpoisoned mutexes +/// need to be handled with care, since certain panics may have been skipped. +/// Here is a non-exhaustive list of situations where this might occur: +/// +/// - If a mutex is locked while a panic is underway, e.g. within a [`Drop`] +/// implementation or a [panic hook], panicking for the second time while the +/// lock is held will leave the mutex unpoisoned. Note that while double panic +/// usually aborts the program, [`catch_unwind`] can prevent this. +/// +/// - Locking and unlocking the mutex across different panic contexts, e.g. by +/// storing the guard to a [`Cell`] within [`Drop::drop`] and accessing it +/// outside, or vice versa, can affect poisoning status in an unexpected way. +/// +/// - Foreign exceptions do not currently trigger poisoning even in absence of +/// other panics. +/// +/// While this rarely happens in realistic code, `unsafe` code cannot rely on +/// poisoning for soundness, since the behavior of poisoning can depend on +/// outside context. Here's an example of **incorrect** use of poisoning: +/// +/// ```rust +/// use std::sync::Mutex; +/// +/// struct MutexBox<T> { +/// data: Mutex<*mut T>, +/// } +/// +/// impl<T> MutexBox<T> { +/// pub fn new(value: T) -> Self { +/// Self { +/// data: Mutex::new(Box::into_raw(Box::new(value))), +/// } +/// } +/// +/// pub fn replace_with(&self, f: impl FnOnce(T) -> T) { +/// let ptr = self.data.lock().expect("poisoned"); +/// // While `f` is running, the data is moved out of `*ptr`. If `f` +/// // panics, `*ptr` keeps pointing at a dropped value. The intention +/// // is that this will poison the mutex, so the following calls to +/// // `replace_with` will panic without reading `*ptr`. But since +/// // poisoning is not guaranteed to occur if this is run from a panic +/// // hook, this can lead to use-after-free. +/// unsafe { +/// (*ptr).write(f((*ptr).read())); +/// } +/// } +/// } +/// ``` /// /// [`new`]: Self::new /// [`lock`]: Self::lock @@ -39,6 +88,9 @@ use crate::sys::sync as sys; /// [`unwrap()`]: Result::unwrap /// [`PoisonError`]: super::PoisonError /// [`into_inner`]: super::PoisonError::into_inner +/// [panic hook]: crate::panic::set_hook +/// [`catch_unwind`]: crate::panic::catch_unwind +/// [`Cell`]: crate::cell::Cell /// /// # Examples /// @@ -650,7 +702,7 @@ impl<T: ?Sized + fmt::Debug> fmt::Debug for Mutex<T> { d.field("data", &&**err.get_ref()); } Err(TryLockError::WouldBlock) => { - d.field("data", &format_args!("<locked>")); + d.field("data", &"<locked>"); } } d.field("poisoned", &self.poison.get()); diff --git a/library/std/src/sync/poison/once.rs b/library/std/src/sync/poison/once.rs index 103e5195407..faf2913c547 100644 --- a/library/std/src/sync/poison/once.rs +++ b/library/std/src/sync/poison/once.rs @@ -136,7 +136,8 @@ impl Once { /// it will *poison* this [`Once`] instance, causing all future invocations of /// `call_once` to also panic. /// - /// This is similar to [poisoning with mutexes][poison]. + /// This is similar to [poisoning with mutexes][poison], but this mechanism + /// is guaranteed to never skip panics within `f`. /// /// [poison]: struct.Mutex.html#poisoning #[inline] @@ -293,6 +294,9 @@ impl Once { /// Blocks the current thread until initialization has completed, ignoring /// poisoning. + /// + /// If this [`Once`] has been poisoned, this function blocks until it + /// becomes completed, unlike [`Once::wait()`], which panics in this case. #[stable(feature = "once_wait", since = "1.86.0")] pub fn wait_force(&self) { if !self.inner.is_completed() { diff --git a/library/std/src/sync/poison/rwlock.rs b/library/std/src/sync/poison/rwlock.rs index 934a173425a..2c92602bc87 100644 --- a/library/std/src/sync/poison/rwlock.rs +++ b/library/std/src/sync/poison/rwlock.rs @@ -46,10 +46,12 @@ use crate::sys::sync as sys; /// /// # Poisoning /// -/// An `RwLock`, like [`Mutex`], will become poisoned on a panic. Note, however, -/// that an `RwLock` may only be poisoned if a panic occurs while it is locked -/// exclusively (write mode). If a panic occurs in any reader, then the lock -/// will not be poisoned. +/// An `RwLock`, like [`Mutex`], will [usually] become poisoned on a panic. Note, +/// however, that an `RwLock` may only be poisoned if a panic occurs while it is +/// locked exclusively (write mode). If a panic occurs in any reader, then the +/// lock will not be poisoned. +/// +/// [usually]: super::Mutex#poisoning /// /// # Examples /// diff --git a/library/std/src/sys/args/common.rs b/library/std/src/sys/args/common.rs index e787105a05a..33f3794ee63 100644 --- a/library/std/src/sys/args/common.rs +++ b/library/std/src/sys/args/common.rs @@ -12,7 +12,7 @@ impl !Sync for Args {} impl Args { #[inline] - pub(super) fn new(args: Vec<OsString>) -> Self { + pub fn new(args: Vec<OsString>) -> Self { Args { iter: args.into_iter() } } } diff --git a/library/std/src/sys/configure_builtins.rs b/library/std/src/sys/configure_builtins.rs new file mode 100644 index 00000000000..9d776b778dc --- /dev/null +++ b/library/std/src/sys/configure_builtins.rs @@ -0,0 +1,22 @@ +/// Hook into .init_array to enable LSE atomic operations at startup, if +/// supported. +#[cfg(all(target_arch = "aarch64", target_os = "linux", not(feature = "compiler-builtins-c")))] +#[used] +#[unsafe(link_section = ".init_array.90")] +static RUST_LSE_INIT: extern "C" fn() = { + extern "C" fn init_lse() { + use crate::arch; + + // This is provided by compiler-builtins::aarch64_linux. + unsafe extern "C" { + fn __rust_enable_lse(); + } + + if arch::is_aarch64_feature_detected!("lse") { + unsafe { + __rust_enable_lse(); + } + } + } + init_lse +}; diff --git a/library/std/src/sys/mod.rs b/library/std/src/sys/mod.rs index f9a02b522e5..8ec0a0e3302 100644 --- a/library/std/src/sys/mod.rs +++ b/library/std/src/sys/mod.rs @@ -1,5 +1,10 @@ #![allow(unsafe_op_in_unsafe_fn)] +/// The configure builtins provides runtime support compiler-builtin features +/// which require dynamic intialization to work as expected, e.g. aarch64 +/// outline-atomics. +mod configure_builtins; + /// The PAL (platform abstraction layer) contains platform-specific abstractions /// for implementing the features in the other submodules, e.g. UNIX file /// descriptors. diff --git a/library/std/src/sys/pal/hermit/thread.rs b/library/std/src/sys/pal/hermit/thread.rs index 9bc5a16b800..cc4734b6819 100644 --- a/library/std/src/sys/pal/hermit/thread.rs +++ b/library/std/src/sys/pal/hermit/thread.rs @@ -58,7 +58,11 @@ impl Thread { } } - pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> { + pub unsafe fn new( + stack: usize, + _name: Option<&str>, + p: Box<dyn FnOnce()>, + ) -> io::Result<Thread> { unsafe { Thread::new_with_coreid(stack, p, -1 /* = no specific core */) } @@ -111,6 +115,10 @@ impl Thread { } } +pub(crate) fn current_os_id() -> Option<u64> { + None +} + pub fn available_parallelism() -> io::Result<NonZero<usize>> { unsafe { Ok(NonZero::new_unchecked(hermit_abi::available_parallelism())) } } diff --git a/library/std/src/sys/pal/itron/thread.rs b/library/std/src/sys/pal/itron/thread.rs index 813e1cbcd58..4e14cb3cbca 100644 --- a/library/std/src/sys/pal/itron/thread.rs +++ b/library/std/src/sys/pal/itron/thread.rs @@ -86,7 +86,11 @@ impl Thread { /// # Safety /// /// See `thread::Builder::spawn_unchecked` for safety requirements. - pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> { + pub unsafe fn new( + stack: usize, + _name: Option<&str>, + p: Box<dyn FnOnce()>, + ) -> io::Result<Thread> { let inner = Box::new(ThreadInner { start: UnsafeCell::new(ManuallyDrop::new(p)), lifecycle: AtomicUsize::new(LIFECYCLE_INIT), @@ -357,6 +361,10 @@ unsafe fn terminate_and_delete_current_task() -> ! { unsafe { crate::hint::unreachable_unchecked() }; } +pub(crate) fn current_os_id() -> Option<u64> { + None +} + pub fn available_parallelism() -> io::Result<NonZero<usize>> { super::unsupported() } diff --git a/library/std/src/sys/pal/sgx/thread.rs b/library/std/src/sys/pal/sgx/thread.rs index 85f6dcd96b4..1f613badcd7 100644 --- a/library/std/src/sys/pal/sgx/thread.rs +++ b/library/std/src/sys/pal/sgx/thread.rs @@ -1,6 +1,6 @@ #![cfg_attr(test, allow(dead_code))] // why is this necessary? -use super::abi::usercalls; +use super::abi::{thread, usercalls}; use super::unsupported; use crate::ffi::CStr; use crate::io; @@ -96,7 +96,11 @@ pub mod wait_notify { impl Thread { // unsafe: see thread::Builder::spawn_unchecked for safety requirements - pub unsafe fn new(_stack: usize, p: Box<dyn FnOnce() + Send>) -> io::Result<Thread> { + pub unsafe fn new( + _stack: usize, + _name: Option<&str>, + p: Box<dyn FnOnce() + Send>, + ) -> io::Result<Thread> { let mut queue_lock = task_queue::lock(); unsafe { usercalls::launch_thread()? }; let (task, handle) = task_queue::Task::new(p); @@ -145,6 +149,10 @@ impl Thread { } } +pub(crate) fn current_os_id() -> Option<u64> { + Some(thread::current().addr().get() as u64) +} + pub fn available_parallelism() -> io::Result<NonZero<usize>> { unsupported() } diff --git a/library/std/src/sys/pal/teeos/thread.rs b/library/std/src/sys/pal/teeos/thread.rs index b9cdc7a2a58..1812d11e692 100644 --- a/library/std/src/sys/pal/teeos/thread.rs +++ b/library/std/src/sys/pal/teeos/thread.rs @@ -22,7 +22,11 @@ unsafe extern "C" { impl Thread { // unsafe: see thread::Builder::spawn_unchecked for safety requirements - pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> { + pub unsafe fn new( + stack: usize, + _name: Option<&str>, + p: Box<dyn FnOnce()>, + ) -> io::Result<Thread> { let p = Box::into_raw(Box::new(p)); let mut native: libc::pthread_t = unsafe { mem::zeroed() }; let mut attr: libc::pthread_attr_t = unsafe { mem::zeroed() }; @@ -140,6 +144,10 @@ impl Drop for Thread { } } +pub(crate) fn current_os_id() -> Option<u64> { + None +} + // Note: Both `sched_getaffinity` and `sysconf` are available but not functional on // teeos, so this function always returns an Error! pub fn available_parallelism() -> io::Result<NonZero<usize>> { diff --git a/library/std/src/sys/pal/uefi/helpers.rs b/library/std/src/sys/pal/uefi/helpers.rs index 271dc4d11de..b50574de937 100644 --- a/library/std/src/sys/pal/uefi/helpers.rs +++ b/library/std/src/sys/pal/uefi/helpers.rs @@ -444,17 +444,17 @@ impl<'a> DevicePathNode<'a> { impl<'a> PartialEq for DevicePathNode<'a> { fn eq(&self, other: &Self) -> bool { - let self_len = self.length(); - let other_len = other.length(); - - self_len == other_len - && unsafe { - compiler_builtins::mem::memcmp( - self.protocol.as_ptr().cast(), - other.protocol.as_ptr().cast(), - usize::from(self_len), - ) == 0 - } + // Compare as a single buffer rather than by field since it optimizes better. + // + // SAFETY: `Protocol` is followed by a buffer of `length - sizeof::<Protocol>()`. `Protocol` + // has no padding so it is sound to interpret as a slice. + unsafe { + let s1 = + slice::from_raw_parts(self.protocol.as_ptr().cast::<u8>(), self.length().into()); + let s2 = + slice::from_raw_parts(other.protocol.as_ptr().cast::<u8>(), other.length().into()); + s1 == s2 + } } } diff --git a/library/std/src/sys/pal/uefi/thread.rs b/library/std/src/sys/pal/uefi/thread.rs index e4776ec42fb..47a48008c76 100644 --- a/library/std/src/sys/pal/uefi/thread.rs +++ b/library/std/src/sys/pal/uefi/thread.rs @@ -11,7 +11,11 @@ pub const DEFAULT_MIN_STACK_SIZE: usize = 64 * 1024; impl Thread { // unsafe: see thread::Builder::spawn_unchecked for safety requirements - pub unsafe fn new(_stack: usize, _p: Box<dyn FnOnce()>) -> io::Result<Thread> { + pub unsafe fn new( + _stack: usize, + _name: Option<&str>, + _p: Box<dyn FnOnce()>, + ) -> io::Result<Thread> { unsupported() } @@ -52,6 +56,10 @@ impl Thread { } } +pub(crate) fn current_os_id() -> Option<u64> { + None +} + pub fn available_parallelism() -> io::Result<NonZero<usize>> { // UEFI is single threaded Ok(NonZero::new(1).unwrap()) diff --git a/library/std/src/sys/pal/unix/stack_overflow.rs b/library/std/src/sys/pal/unix/stack_overflow.rs index a3be2cdf738..0d2100d66bc 100644 --- a/library/std/src/sys/pal/unix/stack_overflow.rs +++ b/library/std/src/sys/pal/unix/stack_overflow.rs @@ -8,8 +8,8 @@ pub struct Handler { } impl Handler { - pub unsafe fn new() -> Handler { - make_handler(false) + pub unsafe fn new(thread_name: Option<Box<str>>) -> Handler { + make_handler(false, thread_name) } fn null() -> Handler { @@ -72,7 +72,6 @@ mod imp { use crate::sync::OnceLock; use crate::sync::atomic::{Atomic, AtomicBool, AtomicPtr, AtomicUsize, Ordering}; use crate::sys::pal::unix::os; - use crate::thread::with_current_name; use crate::{io, mem, panic, ptr}; // Signal handler for the SIGSEGV and SIGBUS handlers. We've got guard pages @@ -120,7 +119,8 @@ mod imp { && thread_info.guard_page_range.contains(&fault_addr) { let name = thread_info.thread_name.as_deref().unwrap_or("<unknown>"); - rtprintpanic!("\nthread '{name}' has overflowed its stack\n"); + let tid = crate::thread::current_os_id(); + rtprintpanic!("\nthread '{name}' ({tid}) has overflowed its stack\n"); rtabort!("stack overflow"); } }) @@ -158,13 +158,12 @@ mod imp { if !NEED_ALTSTACK.load(Ordering::Relaxed) { // haven't set up our sigaltstack yet NEED_ALTSTACK.store(true, Ordering::Release); - let handler = unsafe { make_handler(true) }; + let handler = unsafe { make_handler(true, None) }; MAIN_ALTSTACK.store(handler.data, Ordering::Relaxed); mem::forget(handler); if let Some(guard_page_range) = guard_page_range.take() { - let thread_name = with_current_name(|name| name.map(Box::from)); - set_current_info(guard_page_range, thread_name); + set_current_info(guard_page_range, Some(Box::from("main"))); } } @@ -230,14 +229,13 @@ mod imp { /// # Safety /// Mutates the alternate signal stack #[forbid(unsafe_op_in_unsafe_fn)] - pub unsafe fn make_handler(main_thread: bool) -> Handler { + pub unsafe fn make_handler(main_thread: bool, thread_name: Option<Box<str>>) -> Handler { if !NEED_ALTSTACK.load(Ordering::Acquire) { return Handler::null(); } if !main_thread { if let Some(guard_page_range) = unsafe { current_guard() } { - let thread_name = with_current_name(|name| name.map(Box::from)); set_current_info(guard_page_range, thread_name); } } @@ -634,7 +632,10 @@ mod imp { pub unsafe fn cleanup() {} - pub unsafe fn make_handler(_main_thread: bool) -> super::Handler { + pub unsafe fn make_handler( + _main_thread: bool, + _thread_name: Option<Box<str>>, + ) -> super::Handler { super::Handler::null() } @@ -696,7 +697,8 @@ mod imp { if code == c::EXCEPTION_STACK_OVERFLOW { crate::thread::with_current_name(|name| { let name = name.unwrap_or("<unknown>"); - rtprintpanic!("\nthread '{name}' has overflowed its stack\n"); + let tid = crate::thread::current_os_id(); + rtprintpanic!("\nthread '{name}' ({tid}) has overflowed its stack\n"); }); } c::EXCEPTION_CONTINUE_SEARCH @@ -717,7 +719,10 @@ mod imp { pub unsafe fn cleanup() {} - pub unsafe fn make_handler(main_thread: bool) -> super::Handler { + pub unsafe fn make_handler( + main_thread: bool, + _thread_name: Option<Box<str>>, + ) -> super::Handler { if !main_thread { reserve_stack(); } diff --git a/library/std/src/sys/pal/unix/thread.rs b/library/std/src/sys/pal/unix/thread.rs index e4f5520d8a3..36e53e7cadc 100644 --- a/library/std/src/sys/pal/unix/thread.rs +++ b/library/std/src/sys/pal/unix/thread.rs @@ -22,6 +22,11 @@ pub const DEFAULT_MIN_STACK_SIZE: usize = 256 * 1024; #[cfg(any(target_os = "espidf", target_os = "nuttx"))] pub const DEFAULT_MIN_STACK_SIZE: usize = 0; // 0 indicates that the stack size configured in the ESP-IDF/NuttX menuconfig system should be used +struct ThreadData { + name: Option<Box<str>>, + f: Box<dyn FnOnce()>, +} + pub struct Thread { id: libc::pthread_t, } @@ -34,8 +39,12 @@ unsafe impl Sync for Thread {} impl Thread { // unsafe: see thread::Builder::spawn_unchecked for safety requirements #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces - pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> { - let p = Box::into_raw(Box::new(p)); + pub unsafe fn new( + stack: usize, + name: Option<&str>, + f: Box<dyn FnOnce()>, + ) -> io::Result<Thread> { + let data = Box::into_raw(Box::new(ThreadData { name: name.map(Box::from), f })); let mut native: libc::pthread_t = mem::zeroed(); let mut attr: mem::MaybeUninit<libc::pthread_attr_t> = mem::MaybeUninit::uninit(); assert_eq!(libc::pthread_attr_init(attr.as_mut_ptr()), 0); @@ -73,7 +82,7 @@ impl Thread { }; } - let ret = libc::pthread_create(&mut native, attr.as_ptr(), thread_start, p as *mut _); + let ret = libc::pthread_create(&mut native, attr.as_ptr(), thread_start, data as *mut _); // Note: if the thread creation fails and this assert fails, then p will // be leaked. However, an alternative design could cause double-free // which is clearly worse. @@ -82,19 +91,20 @@ impl Thread { return if ret != 0 { // The thread failed to start and as a result p was not consumed. Therefore, it is // safe to reconstruct the box so that it gets deallocated. - drop(Box::from_raw(p)); + drop(Box::from_raw(data)); Err(io::Error::from_raw_os_error(ret)) } else { Ok(Thread { id: native }) }; - extern "C" fn thread_start(main: *mut libc::c_void) -> *mut libc::c_void { + extern "C" fn thread_start(data: *mut libc::c_void) -> *mut libc::c_void { unsafe { + let data = Box::from_raw(data as *mut ThreadData); // Next, set up our stack overflow handler which may get triggered if we run // out of stack. - let _handler = stack_overflow::Handler::new(); + let _handler = stack_overflow::Handler::new(data.name); // Finally, let's run some code. - Box::from_raw(main as *mut Box<dyn FnOnce()>)(); + (data.f)(); } ptr::null_mut() } @@ -388,6 +398,62 @@ impl Drop for Thread { } } +pub(crate) fn current_os_id() -> Option<u64> { + // Most Unix platforms have a way to query an integer ID of the current thread, all with + // slightly different spellings. + // + // The OS thread ID is used rather than `pthread_self` so as to match what will be displayed + // for process inspection (debuggers, trace, `top`, etc.). + cfg_if::cfg_if! { + // Most platforms have a function returning a `pid_t` or int, which is an `i32`. + if #[cfg(any(target_os = "android", target_os = "linux"))] { + use crate::sys::weak::syscall; + + // `libc::gettid` is only available on glibc 2.30+, but the syscall is available + // since Linux 2.4.11. + syscall!(fn gettid() -> libc::pid_t;); + + // SAFETY: FFI call with no preconditions. + let id: libc::pid_t = unsafe { gettid() }; + Some(id as u64) + } else if #[cfg(target_os = "nto")] { + // SAFETY: FFI call with no preconditions. + let id: libc::pid_t = unsafe { libc::gettid() }; + Some(id as u64) + } else if #[cfg(target_os = "openbsd")] { + // SAFETY: FFI call with no preconditions. + let id: libc::pid_t = unsafe { libc::getthrid() }; + Some(id as u64) + } else if #[cfg(target_os = "freebsd")] { + // SAFETY: FFI call with no preconditions. + let id: libc::c_int = unsafe { libc::pthread_getthreadid_np() }; + Some(id as u64) + } else if #[cfg(target_os = "netbsd")] { + // SAFETY: FFI call with no preconditions. + let id: libc::lwpid_t = unsafe { libc::_lwp_self() }; + Some(id as u64) + } else if #[cfg(any(target_os = "illumos", target_os = "solaris"))] { + // On Illumos and Solaris, the `pthread_t` is the same as the OS thread ID. + // SAFETY: FFI call with no preconditions. + let id: libc::pthread_t = unsafe { libc::pthread_self() }; + Some(id as u64) + } else if #[cfg(target_vendor = "apple")] { + // Apple allows querying arbitrary thread IDs, `thread=NULL` queries the current thread. + let mut id = 0u64; + // SAFETY: `thread_id` is a valid pointer, no other preconditions. + let status: libc::c_int = unsafe { libc::pthread_threadid_np(0, &mut id) }; + if status == 0 { + Some(id) + } else { + None + } + } else { + // Other platforms don't have an OS thread ID or don't have a way to access it. + None + } + } +} + #[cfg(any( target_os = "linux", target_os = "nto", diff --git a/library/std/src/sys/pal/unsupported/thread.rs b/library/std/src/sys/pal/unsupported/thread.rs index 8a3119fa292..34d9b5ec70c 100644 --- a/library/std/src/sys/pal/unsupported/thread.rs +++ b/library/std/src/sys/pal/unsupported/thread.rs @@ -10,7 +10,11 @@ pub const DEFAULT_MIN_STACK_SIZE: usize = 64 * 1024; impl Thread { // unsafe: see thread::Builder::spawn_unchecked for safety requirements - pub unsafe fn new(_stack: usize, _p: Box<dyn FnOnce()>) -> io::Result<Thread> { + pub unsafe fn new( + _stack: usize, + _name: Option<&str>, + _p: Box<dyn FnOnce()>, + ) -> io::Result<Thread> { unsupported() } @@ -35,6 +39,10 @@ impl Thread { } } +pub(crate) fn current_os_id() -> Option<u64> { + None +} + pub fn available_parallelism() -> io::Result<NonZero<usize>> { unsupported() } diff --git a/library/std/src/sys/pal/wasi/thread.rs b/library/std/src/sys/pal/wasi/thread.rs index 5f21a553673..4755e2ef5da 100644 --- a/library/std/src/sys/pal/wasi/thread.rs +++ b/library/std/src/sys/pal/wasi/thread.rs @@ -73,7 +73,7 @@ impl Thread { // unsafe: see thread::Builder::spawn_unchecked for safety requirements cfg_if::cfg_if! { if #[cfg(target_feature = "atomics")] { - pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> { + pub unsafe fn new(stack: usize, _name: Option<&str>, p: Box<dyn FnOnce()>) -> io::Result<Thread> { let p = Box::into_raw(Box::new(p)); let mut native: libc::pthread_t = unsafe { mem::zeroed() }; let mut attr: libc::pthread_attr_t = unsafe { mem::zeroed() }; @@ -120,7 +120,7 @@ impl Thread { } } } else { - pub unsafe fn new(_stack: usize, _p: Box<dyn FnOnce()>) -> io::Result<Thread> { + pub unsafe fn new(_stack: usize, _name: Option<&str>, _p: Box<dyn FnOnce()>) -> io::Result<Thread> { crate::sys::unsupported() } } @@ -194,6 +194,10 @@ impl Thread { } } +pub(crate) fn current_os_id() -> Option<u64> { + None +} + pub fn available_parallelism() -> io::Result<NonZero<usize>> { cfg_if::cfg_if! { if #[cfg(target_feature = "atomics")] { diff --git a/library/std/src/sys/pal/wasm/atomics/thread.rs b/library/std/src/sys/pal/wasm/atomics/thread.rs index 44ce3eab109..42a7dbdf8b8 100644 --- a/library/std/src/sys/pal/wasm/atomics/thread.rs +++ b/library/std/src/sys/pal/wasm/atomics/thread.rs @@ -10,7 +10,11 @@ pub const DEFAULT_MIN_STACK_SIZE: usize = 1024 * 1024; impl Thread { // unsafe: see thread::Builder::spawn_unchecked for safety requirements - pub unsafe fn new(_stack: usize, _p: Box<dyn FnOnce()>) -> io::Result<Thread> { + pub unsafe fn new( + _stack: usize, + _name: Option<&str>, + _p: Box<dyn FnOnce()>, + ) -> io::Result<Thread> { unsupported() } @@ -52,6 +56,10 @@ impl Thread { pub fn join(self) {} } +pub(crate) fn current_os_id() -> Option<u64> { + None +} + pub fn available_parallelism() -> io::Result<NonZero<usize>> { unsupported() } diff --git a/library/std/src/sys/pal/windows/c/bindings.txt b/library/std/src/sys/pal/windows/c/bindings.txt index 827d96e73db..c8e4dca4781 100644 --- a/library/std/src/sys/pal/windows/c/bindings.txt +++ b/library/std/src/sys/pal/windows/c/bindings.txt @@ -2185,6 +2185,7 @@ GetSystemInfo GetSystemTimeAsFileTime GetSystemTimePreciseAsFileTime GetTempPathW +GetThreadId GetUserProfileDirectoryW GetWindowsDirectoryW HANDLE diff --git a/library/std/src/sys/pal/windows/c/windows_sys.rs b/library/std/src/sys/pal/windows/c/windows_sys.rs index b2e3aabc633..45a273d241a 100644 --- a/library/std/src/sys/pal/windows/c/windows_sys.rs +++ b/library/std/src/sys/pal/windows/c/windows_sys.rs @@ -61,6 +61,7 @@ windows_targets::link!("kernel32.dll" "system" fn GetSystemInfo(lpsysteminfo : * windows_targets::link!("kernel32.dll" "system" fn GetSystemTimeAsFileTime(lpsystemtimeasfiletime : *mut FILETIME)); windows_targets::link!("kernel32.dll" "system" fn GetSystemTimePreciseAsFileTime(lpsystemtimeasfiletime : *mut FILETIME)); windows_targets::link!("kernel32.dll" "system" fn GetTempPathW(nbufferlength : u32, lpbuffer : PWSTR) -> u32); +windows_targets::link!("kernel32.dll" "system" fn GetThreadId(thread : HANDLE) -> u32); windows_targets::link!("userenv.dll" "system" fn GetUserProfileDirectoryW(htoken : HANDLE, lpprofiledir : PWSTR, lpcchsize : *mut u32) -> BOOL); windows_targets::link!("kernel32.dll" "system" fn GetWindowsDirectoryW(lpbuffer : PWSTR, usize : u32) -> u32); windows_targets::link!("kernel32.dll" "system" fn InitOnceBeginInitialize(lpinitonce : *mut INIT_ONCE, dwflags : u32, fpending : *mut BOOL, lpcontext : *mut *mut core::ffi::c_void) -> BOOL); diff --git a/library/std/src/sys/pal/windows/stack_overflow.rs b/library/std/src/sys/pal/windows/stack_overflow.rs index 734cd30bed0..9a40551b985 100644 --- a/library/std/src/sys/pal/windows/stack_overflow.rs +++ b/library/std/src/sys/pal/windows/stack_overflow.rs @@ -20,7 +20,8 @@ unsafe extern "system" fn vectored_handler(ExceptionInfo: *mut c::EXCEPTION_POIN if code == c::EXCEPTION_STACK_OVERFLOW { thread::with_current_name(|name| { let name = name.unwrap_or("<unknown>"); - rtprintpanic!("\nthread '{name}' has overflowed its stack\n"); + let tid = thread::current_os_id(); + rtprintpanic!("\nthread '{name}' ({tid}) has overflowed its stack\n"); }); } c::EXCEPTION_CONTINUE_SEARCH diff --git a/library/std/src/sys/pal/windows/thread.rs b/library/std/src/sys/pal/windows/thread.rs index 14785171755..c708da5af12 100644 --- a/library/std/src/sys/pal/windows/thread.rs +++ b/library/std/src/sys/pal/windows/thread.rs @@ -20,7 +20,11 @@ pub struct Thread { impl Thread { // unsafe: see thread::Builder::spawn_unchecked for safety requirements #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces - pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> { + pub unsafe fn new( + stack: usize, + _name: Option<&str>, + p: Box<dyn FnOnce()>, + ) -> io::Result<Thread> { let p = Box::into_raw(Box::new(p)); // CreateThread rounds up values for the stack size to the nearest page size (at least 4kb). @@ -123,6 +127,14 @@ impl Thread { } } +pub(crate) fn current_os_id() -> Option<u64> { + // SAFETY: FFI call with no preconditions. + let id: u32 = unsafe { c::GetThreadId(c::GetCurrentThread()) }; + + // A return value of 0 indicates failed lookup. + if id == 0 { None } else { Some(id.into()) } +} + pub fn available_parallelism() -> io::Result<NonZero<usize>> { let res = unsafe { let mut sysinfo: c::SYSTEM_INFO = crate::mem::zeroed(); diff --git a/library/std/src/sys/pal/xous/thread.rs b/library/std/src/sys/pal/xous/thread.rs index 1b344e984dc..92803c94c6e 100644 --- a/library/std/src/sys/pal/xous/thread.rs +++ b/library/std/src/sys/pal/xous/thread.rs @@ -20,7 +20,11 @@ pub const GUARD_PAGE_SIZE: usize = 4096; impl Thread { // unsafe: see thread::Builder::spawn_unchecked for safety requirements - pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> { + pub unsafe fn new( + stack: usize, + _name: Option<&str>, + p: Box<dyn FnOnce()>, + ) -> io::Result<Thread> { let p = Box::into_raw(Box::new(p)); let mut stack_size = crate::cmp::max(stack, MIN_STACK_SIZE); @@ -141,6 +145,10 @@ impl Thread { } } +pub(crate) fn current_os_id() -> Option<u64> { + None +} + pub fn available_parallelism() -> io::Result<NonZero<usize>> { // We're unicore right now. Ok(unsafe { NonZero::new_unchecked(1) }) diff --git a/library/std/src/sys/random/sgx.rs b/library/std/src/sys/random/sgx.rs index c3647a8df22..462b19003fa 100644 --- a/library/std/src/sys/random/sgx.rs +++ b/library/std/src/sys/random/sgx.rs @@ -46,22 +46,22 @@ fn rdrand16() -> u16 { } pub fn fill_bytes(bytes: &mut [u8]) { - let mut chunks = bytes.array_chunks_mut(); - for chunk in &mut chunks { + let (chunks, remainder) = bytes.as_chunks_mut(); + for chunk in chunks { *chunk = rdrand64().to_ne_bytes(); } - let mut chunks = chunks.into_remainder().array_chunks_mut(); - for chunk in &mut chunks { + let (chunks, remainder) = remainder.as_chunks_mut(); + for chunk in chunks { *chunk = rdrand32().to_ne_bytes(); } - let mut chunks = chunks.into_remainder().array_chunks_mut(); - for chunk in &mut chunks { + let (chunks, remainder) = remainder.as_chunks_mut(); + for chunk in chunks { *chunk = rdrand16().to_ne_bytes(); } - if let [byte] = chunks.into_remainder() { + if let [byte] = remainder { *byte = rdrand16() as u8; } } diff --git a/library/std/src/sys/random/uefi.rs b/library/std/src/sys/random/uefi.rs index 5f001f0f532..4a71d32fffe 100644 --- a/library/std/src/sys/random/uefi.rs +++ b/library/std/src/sys/random/uefi.rs @@ -138,12 +138,11 @@ mod rdrand { } unsafe fn rdrand_exact(dest: &mut [u8]) -> Option<()> { - let mut chunks = dest.array_chunks_mut(); - for chunk in &mut chunks { + let (chunks, tail) = dest.as_chunks_mut(); + for chunk in chunks { *chunk = unsafe { rdrand() }?.to_ne_bytes(); } - let tail = chunks.into_remainder(); let n = tail.len(); if n > 0 { let src = unsafe { rdrand() }?.to_ne_bytes(); diff --git a/library/std/src/thread/current.rs b/library/std/src/thread/current.rs index 414711298f0..5c879903526 100644 --- a/library/std/src/thread/current.rs +++ b/library/std/src/thread/current.rs @@ -1,4 +1,4 @@ -use super::{Thread, ThreadId}; +use super::{Thread, ThreadId, imp}; use crate::mem::ManuallyDrop; use crate::ptr; use crate::sys::thread_local::local_pointer; @@ -148,6 +148,17 @@ pub(crate) fn current_id() -> ThreadId { id::get_or_init() } +/// Gets the OS thread ID of the thread that invokes it, if available. If not, return the Rust +/// thread ID. +/// +/// We use a `u64` to all possible platform IDs without excess `cfg`; most use `int`, some use a +/// pointer, and Apple uses `uint64_t`. This is a "best effort" approach for diagnostics and is +/// allowed to fall back to a non-OS ID (such as the Rust thread ID) or a non-unique ID (such as a +/// PID) if the thread ID cannot be retrieved. +pub(crate) fn current_os_id() -> u64 { + imp::current_os_id().unwrap_or_else(|| current_id().as_u64().get()) +} + /// Gets a reference to the handle of the thread that invokes it, if the handle /// has been initialized. pub(super) fn try_with_current<F, R>(f: F) -> R diff --git a/library/std/src/thread/mod.rs b/library/std/src/thread/mod.rs index 8cd1e0163a1..292323d0118 100644 --- a/library/std/src/thread/mod.rs +++ b/library/std/src/thread/mod.rs @@ -183,7 +183,7 @@ mod current; #[stable(feature = "rust1", since = "1.0.0")] pub use current::current; -pub(crate) use current::{current_id, current_or_unnamed, drop_current}; +pub(crate) use current::{current_id, current_or_unnamed, current_os_id, drop_current}; use current::{set_current, try_with_current}; mod spawnhook; @@ -595,7 +595,7 @@ impl Builder { // Similarly, the `sys` implementation must guarantee that no references to the closure // exist after the thread has terminated, which is signaled by `Thread::join` // returning. - native: unsafe { imp::Thread::new(stack_size, main)? }, + native: unsafe { imp::Thread::new(stack_size, my_thread.name(), main)? }, thread: my_thread, packet: my_packet, }) @@ -2018,6 +2018,9 @@ fn _assert_sync_and_send() { /// which may take time on systems with large numbers of mountpoints. /// (This does not apply to cgroup v2, or to processes not in a /// cgroup.) +/// - It does not attempt to take `ulimit` into account. If there is a limit set on the number of +/// threads, `available_parallelism` cannot know how much of that limit a Rust program should +/// take, or know in a reliable and race-free way how much of that limit is already taken. /// /// On all targets: /// - It may overcount the amount of parallelism available when running in a VM diff --git a/library/std/src/thread/tests.rs b/library/std/src/thread/tests.rs index 59ec48a57d1..ae889f1e778 100644 --- a/library/std/src/thread/tests.rs +++ b/library/std/src/thread/tests.rs @@ -347,6 +347,13 @@ fn test_thread_id_not_equal() { } #[test] +fn test_thread_os_id_not_equal() { + let spawned_id = thread::spawn(|| thread::current_os_id()).join().unwrap(); + let current_id = thread::current_os_id(); + assert!(current_id != spawned_id); +} + +#[test] fn test_scoped_threads_drop_result_before_join() { let actually_finished = &AtomicBool::new(false); struct X<'scope, 'env>(&'scope Scope<'scope, 'env>, &'env AtomicBool); diff --git a/library/std/tests/sync/lib.rs b/library/std/tests/sync/lib.rs index 51190f0894f..94f1fe96b6a 100644 --- a/library/std/tests/sync/lib.rs +++ b/library/std/tests/sync/lib.rs @@ -6,7 +6,10 @@ #![feature(reentrant_lock)] #![feature(rwlock_downgrade)] #![feature(std_internals)] +#![feature(sync_nonpoison)] +#![feature(nonpoison_mutex)] #![allow(internal_features)] +#![feature(macro_metavar_expr_concat)] // For concatenating identifiers in macros. mod barrier; mod condvar; @@ -29,3 +32,55 @@ mod rwlock; #[path = "../common/mod.rs"] mod common; + +#[track_caller] +fn result_unwrap<T, E: std::fmt::Debug>(x: Result<T, E>) -> T { + x.unwrap() +} + +/// A macro that generates two test cases for both the poison and nonpoison locks. +/// +/// To write a test that tests both `poison` and `nonpoison` locks, import any of the types +/// under both `poison` and `nonpoison` using the module name `locks` instead. For example, write +/// `use locks::Mutex;` instead of `use std::sync::poiosn::Mutex`. This will import the correct type +/// for each test variant. +/// +/// Write a test as normal in the `test_body`, but instead of calling `unwrap` on `poison` methods +/// that return a `LockResult` or similar, call the function `maybe_unwrap(...)` on the result. +/// +/// For example, call `maybe_unwrap(mutex.lock())` instead of `mutex.lock().unwrap()` or +/// `maybe_unwrap(rwlock.read())` instead of `rwlock.read().unwrap()`. +/// +/// For the `poison` types, `maybe_unwrap` will simply unwrap the `Result` (usually this is a form +/// of `LockResult`, but it could also be other kinds of results). For the `nonpoison` types, it is +/// a no-op (the identity function). +/// +/// The test names will be prefiex with `poison_` or `nonpoison_`. +macro_rules! nonpoison_and_poison_unwrap_test { + ( + name: $name:ident, + test_body: {$($test_body:tt)*} + ) => { + // Creates the nonpoison test. + #[test] + fn ${concat(nonpoison_, $name)}() { + #[allow(unused_imports)] + use ::std::convert::identity as maybe_unwrap; + use ::std::sync::nonpoison as locks; + + $($test_body)* + } + + // Creates the poison test with the suffix `_unwrap_poisoned`. + #[test] + fn ${concat(poison_, $name)}() { + #[allow(unused_imports)] + use super::result_unwrap as maybe_unwrap; + use ::std::sync::poison as locks; + + $($test_body)* + } + } +} + +use nonpoison_and_poison_unwrap_test; diff --git a/library/std/tests/sync/mutex.rs b/library/std/tests/sync/mutex.rs index ac82914d6de..90cefc0d594 100644 --- a/library/std/tests/sync/mutex.rs +++ b/library/std/tests/sync/mutex.rs @@ -6,7 +6,71 @@ use std::sync::mpsc::channel; use std::sync::{Arc, Condvar, MappedMutexGuard, Mutex, MutexGuard, TryLockError}; use std::{hint, mem, thread}; -struct Packet<T>(Arc<(Mutex<T>, Condvar)>); +//////////////////////////////////////////////////////////////////////////////////////////////////// +// Nonpoison & Poison Tests +//////////////////////////////////////////////////////////////////////////////////////////////////// +use super::nonpoison_and_poison_unwrap_test; + +nonpoison_and_poison_unwrap_test!( + name: smoke, + test_body: { + use locks::Mutex; + + let m = Mutex::new(()); + drop(maybe_unwrap(m.lock())); + drop(maybe_unwrap(m.lock())); + } +); + +nonpoison_and_poison_unwrap_test!( + name: lots_and_lots, + test_body: { + use locks::Mutex; + + const J: u32 = 1000; + const K: u32 = 3; + + let m = Arc::new(Mutex::new(0)); + + fn inc(m: &Mutex<u32>) { + for _ in 0..J { + *maybe_unwrap(m.lock()) += 1; + } + } + + let (tx, rx) = channel(); + for _ in 0..K { + let tx2 = tx.clone(); + let m2 = m.clone(); + thread::spawn(move || { + inc(&m2); + tx2.send(()).unwrap(); + }); + let tx2 = tx.clone(); + let m2 = m.clone(); + thread::spawn(move || { + inc(&m2); + tx2.send(()).unwrap(); + }); + } + + drop(tx); + for _ in 0..2 * K { + rx.recv().unwrap(); + } + assert_eq!(*maybe_unwrap(m.lock()), J * K * 2); + } +); + +nonpoison_and_poison_unwrap_test!( + name: try_lock, + test_body: { + use locks::Mutex; + + let m = Mutex::new(()); + *m.try_lock().unwrap() = (); + } +); #[derive(Eq, PartialEq, Debug)] struct NonCopy(i32); @@ -26,58 +90,278 @@ fn test_needs_drop() { assert!(mem::needs_drop::<NonCopyNeedsDrop>()); } -#[derive(Clone, Eq, PartialEq, Debug)] -struct Cloneable(i32); +nonpoison_and_poison_unwrap_test!( + name: test_into_inner, + test_body: { + use locks::Mutex; -#[test] -fn smoke() { - let m = Mutex::new(()); - drop(m.lock().unwrap()); - drop(m.lock().unwrap()); -} + let m = Mutex::new(NonCopy(10)); + assert_eq!(maybe_unwrap(m.into_inner()), NonCopy(10)); + } +); -#[test] -fn lots_and_lots() { - const J: u32 = 1000; - const K: u32 = 3; +nonpoison_and_poison_unwrap_test!( + name: test_into_inner_drop, + test_body: { + use locks::Mutex; - let m = Arc::new(Mutex::new(0)); + struct Foo(Arc<AtomicUsize>); + impl Drop for Foo { + fn drop(&mut self) { + self.0.fetch_add(1, Ordering::SeqCst); + } + } - fn inc(m: &Mutex<u32>) { - for _ in 0..J { - *m.lock().unwrap() += 1; + let num_drops = Arc::new(AtomicUsize::new(0)); + let m = Mutex::new(Foo(num_drops.clone())); + assert_eq!(num_drops.load(Ordering::SeqCst), 0); + { + let _inner = maybe_unwrap(m.into_inner()); + assert_eq!(num_drops.load(Ordering::SeqCst), 0); } + assert_eq!(num_drops.load(Ordering::SeqCst), 1); } +); - let (tx, rx) = channel(); - for _ in 0..K { - let tx2 = tx.clone(); - let m2 = m.clone(); - thread::spawn(move || { - inc(&m2); - tx2.send(()).unwrap(); - }); - let tx2 = tx.clone(); - let m2 = m.clone(); - thread::spawn(move || { - inc(&m2); - tx2.send(()).unwrap(); - }); +nonpoison_and_poison_unwrap_test!( + name: test_get_mut, + test_body: { + use locks::Mutex; + + let mut m = Mutex::new(NonCopy(10)); + *maybe_unwrap(m.get_mut()) = NonCopy(20); + assert_eq!(maybe_unwrap(m.into_inner()), NonCopy(20)); } +); - drop(tx); - for _ in 0..2 * K { - rx.recv().unwrap(); +nonpoison_and_poison_unwrap_test!( + name: test_get_cloned, + test_body: { + use locks::Mutex; + + #[derive(Clone, Eq, PartialEq, Debug)] + struct Cloneable(i32); + + let m = Mutex::new(Cloneable(10)); + + assert_eq!(maybe_unwrap(m.get_cloned()), Cloneable(10)); } - assert_eq!(*m.lock().unwrap(), J * K * 2); -} +); + +nonpoison_and_poison_unwrap_test!( + name: test_set, + test_body: { + use locks::Mutex; + + fn inner<T>(mut init: impl FnMut() -> T, mut value: impl FnMut() -> T) + where + T: Debug + Eq, + { + let m = Mutex::new(init()); + + assert_eq!(*maybe_unwrap(m.lock()), init()); + maybe_unwrap(m.set(value())); + assert_eq!(*maybe_unwrap(m.lock()), value()); + } + + inner(|| NonCopy(10), || NonCopy(20)); + inner(|| NonCopyNeedsDrop(10), || NonCopyNeedsDrop(20)); + } +); + +// Ensure that old values that are replaced by `set` are correctly dropped. +nonpoison_and_poison_unwrap_test!( + name: test_set_drop, + test_body: { + use locks::Mutex; + + struct Foo(Arc<AtomicUsize>); + impl Drop for Foo { + fn drop(&mut self) { + self.0.fetch_add(1, Ordering::SeqCst); + } + } + + let num_drops = Arc::new(AtomicUsize::new(0)); + let m = Mutex::new(Foo(num_drops.clone())); + assert_eq!(num_drops.load(Ordering::SeqCst), 0); + + let different = Foo(Arc::new(AtomicUsize::new(42))); + maybe_unwrap(m.set(different)); + assert_eq!(num_drops.load(Ordering::SeqCst), 1); + } +); + +nonpoison_and_poison_unwrap_test!( + name: test_replace, + test_body: { + use locks::Mutex; + + fn inner<T>(mut init: impl FnMut() -> T, mut value: impl FnMut() -> T) + where + T: Debug + Eq, + { + let m = Mutex::new(init()); + + assert_eq!(*maybe_unwrap(m.lock()), init()); + assert_eq!(maybe_unwrap(m.replace(value())), init()); + assert_eq!(*maybe_unwrap(m.lock()), value()); + } + inner(|| NonCopy(10), || NonCopy(20)); + inner(|| NonCopyNeedsDrop(10), || NonCopyNeedsDrop(20)); + } +); + +// FIXME(nonpoison_condvar): Move this to the `condvar.rs` test file once `nonpoison::condvar` gets +// implemented. #[test] -fn try_lock() { - let m = Mutex::new(()); - *m.try_lock().unwrap() = (); +fn test_mutex_arc_condvar() { + struct Packet<T>(Arc<(Mutex<T>, Condvar)>); + + let packet = Packet(Arc::new((Mutex::new(false), Condvar::new()))); + let packet2 = Packet(packet.0.clone()); + + let (tx, rx) = channel(); + + let _t = thread::spawn(move || { + // Wait until our parent has taken the lock. + rx.recv().unwrap(); + let &(ref lock, ref cvar) = &*packet2.0; + + // Set the data to `true` and wake up our parent. + let mut guard = lock.lock().unwrap(); + *guard = true; + cvar.notify_one(); + }); + + let &(ref lock, ref cvar) = &*packet.0; + let mut guard = lock.lock().unwrap(); + // Wake up our child. + tx.send(()).unwrap(); + + // Wait until our child has set the data to `true`. + assert!(!*guard); + while !*guard { + guard = cvar.wait(guard).unwrap(); + } } +nonpoison_and_poison_unwrap_test!( + name: test_mutex_arc_nested, + test_body: { + use locks::Mutex; + + // Tests nested mutexes and access + // to underlying data. + let arc = Arc::new(Mutex::new(1)); + let arc2 = Arc::new(Mutex::new(arc)); + let (tx, rx) = channel(); + let _t = thread::spawn(move || { + let lock = maybe_unwrap(arc2.lock()); + let lock2 = maybe_unwrap(lock.lock()); + assert_eq!(*lock2, 1); + tx.send(()).unwrap(); + }); + rx.recv().unwrap(); + } +); + +nonpoison_and_poison_unwrap_test!( + name: test_mutex_unsized, + test_body: { + use locks::Mutex; + + let mutex: &Mutex<[i32]> = &Mutex::new([1, 2, 3]); + { + let b = &mut *maybe_unwrap(mutex.lock()); + b[0] = 4; + b[2] = 5; + } + let comp: &[i32] = &[4, 2, 5]; + assert_eq!(&*maybe_unwrap(mutex.lock()), comp); + } +); + +nonpoison_and_poison_unwrap_test!( + name: test_mapping_mapped_guard, + test_body: { + use locks::{Mutex, MutexGuard, MappedMutexGuard}; + + let arr = [0; 4]; + let lock = Mutex::new(arr); + let guard = maybe_unwrap(lock.lock()); + let guard = MutexGuard::map(guard, |arr| &mut arr[..2]); + let mut guard = MappedMutexGuard::map(guard, |slice| &mut slice[1..]); + assert_eq!(guard.len(), 1); + guard[0] = 42; + drop(guard); + assert_eq!(*maybe_unwrap(lock.lock()), [0, 42, 0, 0]); + } +); + +#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] +nonpoison_and_poison_unwrap_test!( + name: test_panics, + test_body: { + use locks::Mutex; + + let mutex = Mutex::new(42); + + let catch_unwind_result1 = panic::catch_unwind(AssertUnwindSafe(|| { + let _guard1 = maybe_unwrap(mutex.lock()); + + panic!("test panic with mutex once"); + })); + assert!(catch_unwind_result1.is_err()); + + let catch_unwind_result2 = panic::catch_unwind(AssertUnwindSafe(|| { + let _guard2 = maybe_unwrap(mutex.lock()); + + panic!("test panic with mutex twice"); + })); + assert!(catch_unwind_result2.is_err()); + + let catch_unwind_result3 = panic::catch_unwind(AssertUnwindSafe(|| { + let _guard3 = maybe_unwrap(mutex.lock()); + + panic!("test panic with mutex thrice"); + })); + assert!(catch_unwind_result3.is_err()); + } +); + +#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] +nonpoison_and_poison_unwrap_test!( + name: test_mutex_arc_access_in_unwind, + test_body: { + use locks::Mutex; + + let arc = Arc::new(Mutex::new(1)); + let arc2 = arc.clone(); + let _ = thread::spawn(move || -> () { + struct Unwinder { + i: Arc<Mutex<i32>>, + } + impl Drop for Unwinder { + fn drop(&mut self) { + *maybe_unwrap(self.i.lock()) += 1; + } + } + let _u = Unwinder { i: arc2 }; + panic!(); + }) + .join(); + let lock = maybe_unwrap(arc.lock()); + assert_eq!(*lock, 2); + } +); + +//////////////////////////////////////////////////////////////////////////////////////////////////// +// Poison Tests +//////////////////////////////////////////////////////////////////////////////////////////////////// + +/// Creates a mutex that is immediately poisoned. fn new_poisoned_mutex<T>(value: T) -> Mutex<T> { let mutex = Mutex::new(value); @@ -94,30 +378,6 @@ fn new_poisoned_mutex<T>(value: T) -> Mutex<T> { } #[test] -fn test_into_inner() { - let m = Mutex::new(NonCopy(10)); - assert_eq!(m.into_inner().unwrap(), NonCopy(10)); -} - -#[test] -fn test_into_inner_drop() { - struct Foo(Arc<AtomicUsize>); - impl Drop for Foo { - fn drop(&mut self) { - self.0.fetch_add(1, Ordering::SeqCst); - } - } - let num_drops = Arc::new(AtomicUsize::new(0)); - let m = Mutex::new(Foo(num_drops.clone())); - assert_eq!(num_drops.load(Ordering::SeqCst), 0); - { - let _inner = m.into_inner().unwrap(); - assert_eq!(num_drops.load(Ordering::SeqCst), 0); - } - assert_eq!(num_drops.load(Ordering::SeqCst), 1); -} - -#[test] #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] fn test_into_inner_poison() { let m = new_poisoned_mutex(NonCopy(10)); @@ -129,15 +389,11 @@ fn test_into_inner_poison() { } #[test] -fn test_get_cloned() { - let m = Mutex::new(Cloneable(10)); - - assert_eq!(m.get_cloned().unwrap(), Cloneable(10)); -} - -#[test] #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] fn test_get_cloned_poison() { + #[derive(Clone, Eq, PartialEq, Debug)] + struct Cloneable(i32); + let m = new_poisoned_mutex(Cloneable(10)); match m.get_cloned() { @@ -147,13 +403,6 @@ fn test_get_cloned_poison() { } #[test] -fn test_get_mut() { - let mut m = Mutex::new(NonCopy(10)); - *m.get_mut().unwrap() = NonCopy(20); - assert_eq!(m.into_inner().unwrap(), NonCopy(20)); -} - -#[test] #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] fn test_get_mut_poison() { let mut m = new_poisoned_mutex(NonCopy(10)); @@ -165,23 +414,6 @@ fn test_get_mut_poison() { } #[test] -fn test_set() { - fn inner<T>(mut init: impl FnMut() -> T, mut value: impl FnMut() -> T) - where - T: Debug + Eq, - { - let m = Mutex::new(init()); - - assert_eq!(*m.lock().unwrap(), init()); - m.set(value()).unwrap(); - assert_eq!(*m.lock().unwrap(), value()); - } - - inner(|| NonCopy(10), || NonCopy(20)); - inner(|| NonCopyNeedsDrop(10), || NonCopyNeedsDrop(20)); -} - -#[test] #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] fn test_set_poison() { fn inner<T>(mut init: impl FnMut() -> T, mut value: impl FnMut() -> T) @@ -204,23 +436,6 @@ fn test_set_poison() { } #[test] -fn test_replace() { - fn inner<T>(mut init: impl FnMut() -> T, mut value: impl FnMut() -> T) - where - T: Debug + Eq, - { - let m = Mutex::new(init()); - - assert_eq!(*m.lock().unwrap(), init()); - assert_eq!(m.replace(value()).unwrap(), init()); - assert_eq!(*m.lock().unwrap(), value()); - } - - inner(|| NonCopy(10), || NonCopy(20)); - inner(|| NonCopyNeedsDrop(10), || NonCopyNeedsDrop(20)); -} - -#[test] #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] fn test_replace_poison() { fn inner<T>(mut init: impl FnMut() -> T, mut value: impl FnMut() -> T) @@ -243,31 +458,10 @@ fn test_replace_poison() { } #[test] -fn test_mutex_arc_condvar() { - let packet = Packet(Arc::new((Mutex::new(false), Condvar::new()))); - let packet2 = Packet(packet.0.clone()); - let (tx, rx) = channel(); - let _t = thread::spawn(move || { - // wait until parent gets in - rx.recv().unwrap(); - let &(ref lock, ref cvar) = &*packet2.0; - let mut lock = lock.lock().unwrap(); - *lock = true; - cvar.notify_one(); - }); - - let &(ref lock, ref cvar) = &*packet.0; - let mut lock = lock.lock().unwrap(); - tx.send(()).unwrap(); - assert!(!*lock); - while !*lock { - lock = cvar.wait(lock).unwrap(); - } -} - -#[test] #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] fn test_arc_condvar_poison() { + struct Packet<T>(Arc<(Mutex<T>, Condvar)>); + let packet = Packet(Arc::new((Mutex::new(1), Condvar::new()))); let packet2 = Packet(packet.0.clone()); let (tx, rx) = channel(); @@ -327,69 +521,6 @@ fn test_mutex_arc_poison_mapped() { } #[test] -fn test_mutex_arc_nested() { - // Tests nested mutexes and access - // to underlying data. - let arc = Arc::new(Mutex::new(1)); - let arc2 = Arc::new(Mutex::new(arc)); - let (tx, rx) = channel(); - let _t = thread::spawn(move || { - let lock = arc2.lock().unwrap(); - let lock2 = lock.lock().unwrap(); - assert_eq!(*lock2, 1); - tx.send(()).unwrap(); - }); - rx.recv().unwrap(); -} - -#[test] -#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] -fn test_mutex_arc_access_in_unwind() { - let arc = Arc::new(Mutex::new(1)); - let arc2 = arc.clone(); - let _ = thread::spawn(move || -> () { - struct Unwinder { - i: Arc<Mutex<i32>>, - } - impl Drop for Unwinder { - fn drop(&mut self) { - *self.i.lock().unwrap() += 1; - } - } - let _u = Unwinder { i: arc2 }; - panic!(); - }) - .join(); - let lock = arc.lock().unwrap(); - assert_eq!(*lock, 2); -} - -#[test] -fn test_mutex_unsized() { - let mutex: &Mutex<[i32]> = &Mutex::new([1, 2, 3]); - { - let b = &mut *mutex.lock().unwrap(); - b[0] = 4; - b[2] = 5; - } - let comp: &[i32] = &[4, 2, 5]; - assert_eq!(&*mutex.lock().unwrap(), comp); -} - -#[test] -fn test_mapping_mapped_guard() { - let arr = [0; 4]; - let mut lock = Mutex::new(arr); - let guard = lock.lock().unwrap(); - let guard = MutexGuard::map(guard, |arr| &mut arr[..2]); - let mut guard = MappedMutexGuard::map(guard, |slice| &mut slice[1..]); - assert_eq!(guard.len(), 1); - guard[0] = 42; - drop(guard); - assert_eq!(*lock.get_mut().unwrap(), [0, 42, 0, 0]); -} - -#[test] #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")] fn panic_while_mapping_unlocked_poison() { let lock = Mutex::new(()); |