3b63e16552
Add more code spans to docs in intrinsics.rs I have added some more code spans in core/src/intrinsics.rs, changing some `=` to `==`, etc. I also changed the wording in some sections.
2033 lines
91 KiB
Rust
2033 lines
91 KiB
Rust
//! Compiler intrinsics.
|
||
//!
|
||
//! The corresponding definitions are in `compiler/rustc_codegen_llvm/src/intrinsic.rs`.
|
||
//! The corresponding const implementations are in `compiler/rustc_mir/src/interpret/intrinsics.rs`
|
||
//!
|
||
//! # Const intrinsics
|
||
//!
|
||
//! Note: any changes to the constness of intrinsics should be discussed with the language team.
|
||
//! This includes changes in the stability of the constness.
|
||
//!
|
||
//! In order to make an intrinsic usable at compile-time, one needs to copy the implementation
|
||
//! from <https://github.com/rust-lang/miri/blob/master/src/shims/intrinsics.rs> to
|
||
//! `compiler/rustc_mir/src/interpret/intrinsics.rs` and add a
|
||
//! `#[rustc_const_unstable(feature = "foo", issue = "01234")]` to the intrinsic.
|
||
//!
|
||
//! If an intrinsic is supposed to be used from a `const fn` with a `rustc_const_stable` attribute,
|
||
//! the intrinsic's attribute must be `rustc_const_stable`, too. Such a change should not be done
|
||
//! without T-lang consultation, because it bakes a feature into the language that cannot be
|
||
//! replicated in user code without compiler support.
|
||
//!
|
||
//! # Volatiles
|
||
//!
|
||
//! The volatile intrinsics provide operations intended to act on I/O
|
||
//! memory, which are guaranteed to not be reordered by the compiler
|
||
//! across other volatile intrinsics. See the LLVM documentation on
|
||
//! [[volatile]].
|
||
//!
|
||
//! [volatile]: http://llvm.org/docs/LangRef.html#volatile-memory-accesses
|
||
//!
|
||
//! # Atomics
|
||
//!
|
||
//! The atomic intrinsics provide common atomic operations on machine
|
||
//! words, with multiple possible memory orderings. They obey the same
|
||
//! semantics as C++11. See the LLVM documentation on [[atomics]].
|
||
//!
|
||
//! [atomics]: http://llvm.org/docs/Atomics.html
|
||
//!
|
||
//! A quick refresher on memory ordering:
|
||
//!
|
||
//! * Acquire - a barrier for acquiring a lock. Subsequent reads and writes
|
||
//! take place after the barrier.
|
||
//! * Release - a barrier for releasing a lock. Preceding reads and writes
|
||
//! take place before the barrier.
|
||
//! * Sequentially consistent - sequentially consistent operations are
|
||
//! guaranteed to happen in order. This is the standard mode for working
|
||
//! with atomic types and is equivalent to Java's `volatile`.
|
||
|
||
#![unstable(
|
||
feature = "core_intrinsics",
|
||
reason = "intrinsics are unlikely to ever be stabilized, instead \
|
||
they should be used through stabilized interfaces \
|
||
in the rest of the standard library",
|
||
issue = "none"
|
||
)]
|
||
#![allow(missing_docs)]
|
||
|
||
use crate::marker::DiscriminantKind;
|
||
use crate::mem;
|
||
|
||
// These imports are used for simplifying intra-doc links
|
||
#[allow(unused_imports)]
|
||
#[cfg(all(target_has_atomic = "8", target_has_atomic = "32", target_has_atomic = "ptr"))]
|
||
use crate::sync::atomic::{self, AtomicBool, AtomicI32, AtomicIsize, AtomicU32, Ordering};
|
||
|
||
#[stable(feature = "drop_in_place", since = "1.8.0")]
|
||
#[rustc_deprecated(
|
||
reason = "no longer an intrinsic - use `ptr::drop_in_place` directly",
|
||
since = "1.18.0"
|
||
)]
|
||
pub use crate::ptr::drop_in_place;
|
||
|
||
extern "rust-intrinsic" {
|
||
// N.B., these intrinsics take raw pointers because they mutate aliased
|
||
// memory, which is not valid for either `&` or `&mut`.
|
||
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange` method by passing
|
||
/// [`Ordering::SeqCst`] as both the `success` and `failure` parameters.
|
||
/// For example, [`AtomicBool::compare_exchange`].
|
||
pub fn atomic_cxchg<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange` method by passing
|
||
/// [`Ordering::Acquire`] as both the `success` and `failure` parameters.
|
||
/// For example, [`AtomicBool::compare_exchange`].
|
||
pub fn atomic_cxchg_acq<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange` method by passing
|
||
/// [`Ordering::Release`] as the `success` and [`Ordering::Relaxed`] as the
|
||
/// `failure` parameters. For example, [`AtomicBool::compare_exchange`].
|
||
pub fn atomic_cxchg_rel<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange` method by passing
|
||
/// [`Ordering::AcqRel`] as the `success` and [`Ordering::Acquire`] as the
|
||
/// `failure` parameters. For example, [`AtomicBool::compare_exchange`].
|
||
pub fn atomic_cxchg_acqrel<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange` method by passing
|
||
/// [`Ordering::Relaxed`] as both the `success` and `failure` parameters.
|
||
/// For example, [`AtomicBool::compare_exchange`].
|
||
pub fn atomic_cxchg_relaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange` method by passing
|
||
/// [`Ordering::SeqCst`] as the `success` and [`Ordering::Relaxed`] as the
|
||
/// `failure` parameters. For example, [`AtomicBool::compare_exchange`].
|
||
pub fn atomic_cxchg_failrelaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange` method by passing
|
||
/// [`Ordering::SeqCst`] as the `success` and [`Ordering::Acquire`] as the
|
||
/// `failure` parameters. For example, [`AtomicBool::compare_exchange`].
|
||
pub fn atomic_cxchg_failacq<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange` method by passing
|
||
/// [`Ordering::Acquire`] as the `success` and [`Ordering::Relaxed`] as the
|
||
/// `failure` parameters. For example, [`AtomicBool::compare_exchange`].
|
||
pub fn atomic_cxchg_acq_failrelaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange` method by passing
|
||
/// [`Ordering::AcqRel`] as the `success` and [`Ordering::Relaxed`] as the
|
||
/// `failure` parameters. For example, [`AtomicBool::compare_exchange`].
|
||
pub fn atomic_cxchg_acqrel_failrelaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange_weak` method by passing
|
||
/// [`Ordering::SeqCst`] as both the `success` and `failure` parameters.
|
||
/// For example, [`AtomicBool::compare_exchange_weak`].
|
||
pub fn atomic_cxchgweak<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange_weak` method by passing
|
||
/// [`Ordering::Acquire`] as both the `success` and `failure` parameters.
|
||
/// For example, [`AtomicBool::compare_exchange_weak`].
|
||
pub fn atomic_cxchgweak_acq<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange_weak` method by passing
|
||
/// [`Ordering::Release`] as the `success` and [`Ordering::Relaxed`] as the
|
||
/// `failure` parameters. For example, [`AtomicBool::compare_exchange_weak`].
|
||
pub fn atomic_cxchgweak_rel<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange_weak` method by passing
|
||
/// [`Ordering::AcqRel`] as the `success` and [`Ordering::Acquire`] as the
|
||
/// `failure` parameters. For example, [`AtomicBool::compare_exchange_weak`].
|
||
pub fn atomic_cxchgweak_acqrel<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange_weak` method by passing
|
||
/// [`Ordering::Relaxed`] as both the `success` and `failure` parameters.
|
||
/// For example, [`AtomicBool::compare_exchange_weak`].
|
||
pub fn atomic_cxchgweak_relaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange_weak` method by passing
|
||
/// [`Ordering::SeqCst`] as the `success` and [`Ordering::Relaxed`] as the
|
||
/// `failure` parameters. For example, [`AtomicBool::compare_exchange_weak`].
|
||
pub fn atomic_cxchgweak_failrelaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange_weak` method by passing
|
||
/// [`Ordering::SeqCst`] as the `success` and [`Ordering::Acquire`] as the
|
||
/// `failure` parameters. For example, [`AtomicBool::compare_exchange_weak`].
|
||
pub fn atomic_cxchgweak_failacq<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange_weak` method by passing
|
||
/// [`Ordering::Acquire`] as the `success` and [`Ordering::Relaxed`] as the
|
||
/// `failure` parameters. For example, [`AtomicBool::compare_exchange_weak`].
|
||
pub fn atomic_cxchgweak_acq_failrelaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
/// Stores a value if the current value is the same as the `old` value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `compare_exchange_weak` method by passing
|
||
/// [`Ordering::AcqRel`] as the `success` and [`Ordering::Relaxed`] as the
|
||
/// `failure` parameters. For example, [`AtomicBool::compare_exchange_weak`].
|
||
pub fn atomic_cxchgweak_acqrel_failrelaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool);
|
||
|
||
/// Loads the current value of the pointer.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `load` method by passing
|
||
/// [`Ordering::SeqCst`] as the `order`. For example, [`AtomicBool::load`].
|
||
pub fn atomic_load<T: Copy>(src: *const T) -> T;
|
||
/// Loads the current value of the pointer.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `load` method by passing
|
||
/// [`Ordering::Acquire`] as the `order`. For example, [`AtomicBool::load`].
|
||
pub fn atomic_load_acq<T: Copy>(src: *const T) -> T;
|
||
/// Loads the current value of the pointer.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `load` method by passing
|
||
/// [`Ordering::Relaxed`] as the `order`. For example, [`AtomicBool::load`].
|
||
pub fn atomic_load_relaxed<T: Copy>(src: *const T) -> T;
|
||
pub fn atomic_load_unordered<T: Copy>(src: *const T) -> T;
|
||
|
||
/// Stores the value at the specified memory location.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `store` method by passing
|
||
/// [`Ordering::SeqCst`] as the `order`. For example, [`AtomicBool::store`].
|
||
pub fn atomic_store<T: Copy>(dst: *mut T, val: T);
|
||
/// Stores the value at the specified memory location.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `store` method by passing
|
||
/// [`Ordering::Release`] as the `order`. For example, [`AtomicBool::store`].
|
||
pub fn atomic_store_rel<T: Copy>(dst: *mut T, val: T);
|
||
/// Stores the value at the specified memory location.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `store` method by passing
|
||
/// [`Ordering::Relaxed`] as the `order`. For example, [`AtomicBool::store`].
|
||
pub fn atomic_store_relaxed<T: Copy>(dst: *mut T, val: T);
|
||
pub fn atomic_store_unordered<T: Copy>(dst: *mut T, val: T);
|
||
|
||
/// Stores the value at the specified memory location, returning the old value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `swap` method by passing
|
||
/// [`Ordering::SeqCst`] as the `order`. For example, [`AtomicBool::swap`].
|
||
pub fn atomic_xchg<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Stores the value at the specified memory location, returning the old value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `swap` method by passing
|
||
/// [`Ordering::Acquire`] as the `order`. For example, [`AtomicBool::swap`].
|
||
pub fn atomic_xchg_acq<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Stores the value at the specified memory location, returning the old value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `swap` method by passing
|
||
/// [`Ordering::Release`] as the `order`. For example, [`AtomicBool::swap`].
|
||
pub fn atomic_xchg_rel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Stores the value at the specified memory location, returning the old value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `swap` method by passing
|
||
/// [`Ordering::AcqRel`] as the `order`. For example, [`AtomicBool::swap`].
|
||
pub fn atomic_xchg_acqrel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Stores the value at the specified memory location, returning the old value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `swap` method by passing
|
||
/// [`Ordering::Relaxed`] as the `order`. For example, [`AtomicBool::swap`].
|
||
pub fn atomic_xchg_relaxed<T: Copy>(dst: *mut T, src: T) -> T;
|
||
|
||
/// Adds to the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_add` method by passing
|
||
/// [`Ordering::SeqCst`] as the `order`. For example, [`AtomicIsize::fetch_add`].
|
||
pub fn atomic_xadd<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Adds to the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_add` method by passing
|
||
/// [`Ordering::Acquire`] as the `order`. For example, [`AtomicIsize::fetch_add`].
|
||
pub fn atomic_xadd_acq<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Adds to the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_add` method by passing
|
||
/// [`Ordering::Release`] as the `order`. For example, [`AtomicIsize::fetch_add`].
|
||
pub fn atomic_xadd_rel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Adds to the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_add` method by passing
|
||
/// [`Ordering::AcqRel`] as the `order`. For example, [`AtomicIsize::fetch_add`].
|
||
pub fn atomic_xadd_acqrel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Adds to the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_add` method by passing
|
||
/// [`Ordering::Relaxed`] as the `order`. For example, [`AtomicIsize::fetch_add`].
|
||
pub fn atomic_xadd_relaxed<T: Copy>(dst: *mut T, src: T) -> T;
|
||
|
||
/// Subtract from the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_sub` method by passing
|
||
/// [`Ordering::SeqCst`] as the `order`. For example, [`AtomicIsize::fetch_sub`].
|
||
pub fn atomic_xsub<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Subtract from the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_sub` method by passing
|
||
/// [`Ordering::Acquire`] as the `order`. For example, [`AtomicIsize::fetch_sub`].
|
||
pub fn atomic_xsub_acq<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Subtract from the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_sub` method by passing
|
||
/// [`Ordering::Release`] as the `order`. For example, [`AtomicIsize::fetch_sub`].
|
||
pub fn atomic_xsub_rel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Subtract from the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_sub` method by passing
|
||
/// [`Ordering::AcqRel`] as the `order`. For example, [`AtomicIsize::fetch_sub`].
|
||
pub fn atomic_xsub_acqrel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Subtract from the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_sub` method by passing
|
||
/// [`Ordering::Relaxed`] as the `order`. For example, [`AtomicIsize::fetch_sub`].
|
||
pub fn atomic_xsub_relaxed<T: Copy>(dst: *mut T, src: T) -> T;
|
||
|
||
/// Bitwise and with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_and` method by passing
|
||
/// [`Ordering::SeqCst`] as the `order`. For example, [`AtomicBool::fetch_and`].
|
||
pub fn atomic_and<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise and with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_and` method by passing
|
||
/// [`Ordering::Acquire`] as the `order`. For example, [`AtomicBool::fetch_and`].
|
||
pub fn atomic_and_acq<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise and with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_and` method by passing
|
||
/// [`Ordering::Release`] as the `order`. For example, [`AtomicBool::fetch_and`].
|
||
pub fn atomic_and_rel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise and with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_and` method by passing
|
||
/// [`Ordering::AcqRel`] as the `order`. For example, [`AtomicBool::fetch_and`].
|
||
pub fn atomic_and_acqrel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise and with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_and` method by passing
|
||
/// [`Ordering::Relaxed`] as the `order`. For example, [`AtomicBool::fetch_and`].
|
||
pub fn atomic_and_relaxed<T: Copy>(dst: *mut T, src: T) -> T;
|
||
|
||
/// Bitwise nand with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`AtomicBool`] type via the `fetch_nand` method by passing
|
||
/// [`Ordering::SeqCst`] as the `order`. For example, [`AtomicBool::fetch_nand`].
|
||
pub fn atomic_nand<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise nand with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`AtomicBool`] type via the `fetch_nand` method by passing
|
||
/// [`Ordering::Acquire`] as the `order`. For example, [`AtomicBool::fetch_nand`].
|
||
pub fn atomic_nand_acq<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise nand with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`AtomicBool`] type via the `fetch_nand` method by passing
|
||
/// [`Ordering::Release`] as the `order`. For example, [`AtomicBool::fetch_nand`].
|
||
pub fn atomic_nand_rel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise nand with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`AtomicBool`] type via the `fetch_nand` method by passing
|
||
/// [`Ordering::AcqRel`] as the `order`. For example, [`AtomicBool::fetch_nand`].
|
||
pub fn atomic_nand_acqrel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise nand with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`AtomicBool`] type via the `fetch_nand` method by passing
|
||
/// [`Ordering::Relaxed`] as the `order`. For example, [`AtomicBool::fetch_nand`].
|
||
pub fn atomic_nand_relaxed<T: Copy>(dst: *mut T, src: T) -> T;
|
||
|
||
/// Bitwise or with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_or` method by passing
|
||
/// [`Ordering::SeqCst`] as the `order`. For example, [`AtomicBool::fetch_or`].
|
||
pub fn atomic_or<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise or with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_or` method by passing
|
||
/// [`Ordering::Acquire`] as the `order`. For example, [`AtomicBool::fetch_or`].
|
||
pub fn atomic_or_acq<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise or with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_or` method by passing
|
||
/// [`Ordering::Release`] as the `order`. For example, [`AtomicBool::fetch_or`].
|
||
pub fn atomic_or_rel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise or with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_or` method by passing
|
||
/// [`Ordering::AcqRel`] as the `order`. For example, [`AtomicBool::fetch_or`].
|
||
pub fn atomic_or_acqrel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise or with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_or` method by passing
|
||
/// [`Ordering::Relaxed`] as the `order`. For example, [`AtomicBool::fetch_or`].
|
||
pub fn atomic_or_relaxed<T: Copy>(dst: *mut T, src: T) -> T;
|
||
|
||
/// Bitwise xor with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_xor` method by passing
|
||
/// [`Ordering::SeqCst`] as the `order`. For example, [`AtomicBool::fetch_xor`].
|
||
pub fn atomic_xor<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise xor with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_xor` method by passing
|
||
/// [`Ordering::Acquire`] as the `order`. For example, [`AtomicBool::fetch_xor`].
|
||
pub fn atomic_xor_acq<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise xor with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_xor` method by passing
|
||
/// [`Ordering::Release`] as the `order`. For example, [`AtomicBool::fetch_xor`].
|
||
pub fn atomic_xor_rel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise xor with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_xor` method by passing
|
||
/// [`Ordering::AcqRel`] as the `order`. For example, [`AtomicBool::fetch_xor`].
|
||
pub fn atomic_xor_acqrel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Bitwise xor with the current value, returning the previous value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] types via the `fetch_xor` method by passing
|
||
/// [`Ordering::Relaxed`] as the `order`. For example, [`AtomicBool::fetch_xor`].
|
||
pub fn atomic_xor_relaxed<T: Copy>(dst: *mut T, src: T) -> T;
|
||
|
||
/// Maximum with the current value using a signed comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] signed integer types via the `fetch_max` method by passing
|
||
/// [`Ordering::SeqCst`] as the `order`. For example, [`AtomicI32::fetch_max`].
|
||
pub fn atomic_max<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Maximum with the current value using a signed comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] signed integer types via the `fetch_max` method by passing
|
||
/// [`Ordering::Acquire`] as the `order`. For example, [`AtomicI32::fetch_max`].
|
||
pub fn atomic_max_acq<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Maximum with the current value using a signed comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] signed integer types via the `fetch_max` method by passing
|
||
/// [`Ordering::Release`] as the `order`. For example, [`AtomicI32::fetch_max`].
|
||
pub fn atomic_max_rel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Maximum with the current value using a signed comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] signed integer types via the `fetch_max` method by passing
|
||
/// [`Ordering::AcqRel`] as the `order`. For example, [`AtomicI32::fetch_max`].
|
||
pub fn atomic_max_acqrel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Maximum with the current value.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] signed integer types via the `fetch_max` method by passing
|
||
/// [`Ordering::Relaxed`] as the `order`. For example, [`AtomicI32::fetch_max`].
|
||
pub fn atomic_max_relaxed<T: Copy>(dst: *mut T, src: T) -> T;
|
||
|
||
/// Minimum with the current value using a signed comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] signed integer types via the `fetch_min` method by passing
|
||
/// [`Ordering::SeqCst`] as the `order`. For example, [`AtomicI32::fetch_min`].
|
||
pub fn atomic_min<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Minimum with the current value using a signed comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] signed integer types via the `fetch_min` method by passing
|
||
/// [`Ordering::Acquire`] as the `order`. For example, [`AtomicI32::fetch_min`].
|
||
pub fn atomic_min_acq<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Minimum with the current value using a signed comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] signed integer types via the `fetch_min` method by passing
|
||
/// [`Ordering::Release`] as the `order`. For example, [`AtomicI32::fetch_min`].
|
||
pub fn atomic_min_rel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Minimum with the current value using a signed comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] signed integer types via the `fetch_min` method by passing
|
||
/// [`Ordering::AcqRel`] as the `order`. For example, [`AtomicI32::fetch_min`].
|
||
pub fn atomic_min_acqrel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Minimum with the current value using a signed comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] signed integer types via the `fetch_min` method by passing
|
||
/// [`Ordering::Relaxed`] as the `order`. For example, [`AtomicI32::fetch_min`].
|
||
pub fn atomic_min_relaxed<T: Copy>(dst: *mut T, src: T) -> T;
|
||
|
||
/// Minimum with the current value using an unsigned comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] unsigned integer types via the `fetch_min` method by passing
|
||
/// [`Ordering::SeqCst`] as the `order`. For example, [`AtomicU32::fetch_min`].
|
||
pub fn atomic_umin<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Minimum with the current value using an unsigned comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] unsigned integer types via the `fetch_min` method by passing
|
||
/// [`Ordering::Acquire`] as the `order`. For example, [`AtomicU32::fetch_min`].
|
||
pub fn atomic_umin_acq<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Minimum with the current value using an unsigned comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] unsigned integer types via the `fetch_min` method by passing
|
||
/// [`Ordering::Release`] as the `order`. For example, [`AtomicU32::fetch_min`].
|
||
pub fn atomic_umin_rel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Minimum with the current value using an unsigned comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] unsigned integer types via the `fetch_min` method by passing
|
||
/// [`Ordering::AcqRel`] as the `order`. For example, [`AtomicU32::fetch_min`].
|
||
pub fn atomic_umin_acqrel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Minimum with the current value using an unsigned comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] unsigned integer types via the `fetch_min` method by passing
|
||
/// [`Ordering::Relaxed`] as the `order`. For example, [`AtomicU32::fetch_min`].
|
||
pub fn atomic_umin_relaxed<T: Copy>(dst: *mut T, src: T) -> T;
|
||
|
||
/// Maximum with the current value using an unsigned comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] unsigned integer types via the `fetch_max` method by passing
|
||
/// [`Ordering::SeqCst`] as the `order`. For example, [`AtomicU32::fetch_max`].
|
||
pub fn atomic_umax<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Maximum with the current value using an unsigned comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] unsigned integer types via the `fetch_max` method by passing
|
||
/// [`Ordering::Acquire`] as the `order`. For example, [`AtomicU32::fetch_max`].
|
||
pub fn atomic_umax_acq<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Maximum with the current value using an unsigned comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] unsigned integer types via the `fetch_max` method by passing
|
||
/// [`Ordering::Release`] as the `order`. For example, [`AtomicU32::fetch_max`].
|
||
pub fn atomic_umax_rel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Maximum with the current value using an unsigned comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] unsigned integer types via the `fetch_max` method by passing
|
||
/// [`Ordering::AcqRel`] as the `order`. For example, [`AtomicU32::fetch_max`].
|
||
pub fn atomic_umax_acqrel<T: Copy>(dst: *mut T, src: T) -> T;
|
||
/// Maximum with the current value using an unsigned comparison.
|
||
///
|
||
/// The stabilized version of this intrinsic is available on the
|
||
/// [`atomic`] unsigned integer types via the `fetch_max` method by passing
|
||
/// [`Ordering::Relaxed`] as the `order`. For example, [`AtomicU32::fetch_max`].
|
||
pub fn atomic_umax_relaxed<T: Copy>(dst: *mut T, src: T) -> T;
|
||
|
||
/// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
|
||
/// if supported; otherwise, it is a no-op.
|
||
/// Prefetches have no effect on the behavior of the program but can change its performance
|
||
/// characteristics.
|
||
///
|
||
/// The `locality` argument must be a constant integer and is a temporal locality specifier
|
||
/// ranging from (0) - no locality, to (3) - extremely local keep in cache.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn prefetch_read_data<T>(data: *const T, locality: i32);
|
||
/// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
|
||
/// if supported; otherwise, it is a no-op.
|
||
/// Prefetches have no effect on the behavior of the program but can change its performance
|
||
/// characteristics.
|
||
///
|
||
/// The `locality` argument must be a constant integer and is a temporal locality specifier
|
||
/// ranging from (0) - no locality, to (3) - extremely local keep in cache.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn prefetch_write_data<T>(data: *const T, locality: i32);
|
||
/// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
|
||
/// if supported; otherwise, it is a no-op.
|
||
/// Prefetches have no effect on the behavior of the program but can change its performance
|
||
/// characteristics.
|
||
///
|
||
/// The `locality` argument must be a constant integer and is a temporal locality specifier
|
||
/// ranging from (0) - no locality, to (3) - extremely local keep in cache.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn prefetch_read_instruction<T>(data: *const T, locality: i32);
|
||
/// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
|
||
/// if supported; otherwise, it is a no-op.
|
||
/// Prefetches have no effect on the behavior of the program but can change its performance
|
||
/// characteristics.
|
||
///
|
||
/// The `locality` argument must be a constant integer and is a temporal locality specifier
|
||
/// ranging from (0) - no locality, to (3) - extremely local keep in cache.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn prefetch_write_instruction<T>(data: *const T, locality: i32);
|
||
}
|
||
|
||
extern "rust-intrinsic" {
|
||
/// An atomic fence.
|
||
///
|
||
/// The stabilized version of this intrinsic is available in
|
||
/// [`atomic::fence`] by passing [`Ordering::SeqCst`]
|
||
/// as the `order`.
|
||
pub fn atomic_fence();
|
||
/// An atomic fence.
|
||
///
|
||
/// The stabilized version of this intrinsic is available in
|
||
/// [`atomic::fence`] by passing [`Ordering::Acquire`]
|
||
/// as the `order`.
|
||
pub fn atomic_fence_acq();
|
||
/// An atomic fence.
|
||
///
|
||
/// The stabilized version of this intrinsic is available in
|
||
/// [`atomic::fence`] by passing [`Ordering::Release`]
|
||
/// as the `order`.
|
||
pub fn atomic_fence_rel();
|
||
/// An atomic fence.
|
||
///
|
||
/// The stabilized version of this intrinsic is available in
|
||
/// [`atomic::fence`] by passing [`Ordering::AcqRel`]
|
||
/// as the `order`.
|
||
pub fn atomic_fence_acqrel();
|
||
|
||
/// A compiler-only memory barrier.
|
||
///
|
||
/// Memory accesses will never be reordered across this barrier by the
|
||
/// compiler, but no instructions will be emitted for it. This is
|
||
/// appropriate for operations on the same thread that may be preempted,
|
||
/// such as when interacting with signal handlers.
|
||
///
|
||
/// The stabilized version of this intrinsic is available in
|
||
/// [`atomic::compiler_fence`] by passing [`Ordering::SeqCst`]
|
||
/// as the `order`.
|
||
pub fn atomic_singlethreadfence();
|
||
/// A compiler-only memory barrier.
|
||
///
|
||
/// Memory accesses will never be reordered across this barrier by the
|
||
/// compiler, but no instructions will be emitted for it. This is
|
||
/// appropriate for operations on the same thread that may be preempted,
|
||
/// such as when interacting with signal handlers.
|
||
///
|
||
/// The stabilized version of this intrinsic is available in
|
||
/// [`atomic::compiler_fence`] by passing [`Ordering::Acquire`]
|
||
/// as the `order`.
|
||
pub fn atomic_singlethreadfence_acq();
|
||
/// A compiler-only memory barrier.
|
||
///
|
||
/// Memory accesses will never be reordered across this barrier by the
|
||
/// compiler, but no instructions will be emitted for it. This is
|
||
/// appropriate for operations on the same thread that may be preempted,
|
||
/// such as when interacting with signal handlers.
|
||
///
|
||
/// The stabilized version of this intrinsic is available in
|
||
/// [`atomic::compiler_fence`] by passing [`Ordering::Release`]
|
||
/// as the `order`.
|
||
pub fn atomic_singlethreadfence_rel();
|
||
/// A compiler-only memory barrier.
|
||
///
|
||
/// Memory accesses will never be reordered across this barrier by the
|
||
/// compiler, but no instructions will be emitted for it. This is
|
||
/// appropriate for operations on the same thread that may be preempted,
|
||
/// such as when interacting with signal handlers.
|
||
///
|
||
/// The stabilized version of this intrinsic is available in
|
||
/// [`atomic::compiler_fence`] by passing [`Ordering::AcqRel`]
|
||
/// as the `order`.
|
||
pub fn atomic_singlethreadfence_acqrel();
|
||
|
||
/// Magic intrinsic that derives its meaning from attributes
|
||
/// attached to the function.
|
||
///
|
||
/// For example, dataflow uses this to inject static assertions so
|
||
/// that `rustc_peek(potentially_uninitialized)` would actually
|
||
/// double-check that dataflow did indeed compute that it is
|
||
/// uninitialized at that point in the control flow.
|
||
///
|
||
/// This intrinsic should not be used outside of the compiler.
|
||
pub fn rustc_peek<T>(_: T) -> T;
|
||
|
||
/// Aborts the execution of the process.
|
||
///
|
||
/// A more user-friendly and stable version of this operation is
|
||
/// [`std::process::abort`](../../std/process/fn.abort.html).
|
||
pub fn abort() -> !;
|
||
|
||
/// Informs the optimizer that this point in the code is not reachable,
|
||
/// enabling further optimizations.
|
||
///
|
||
/// N.B., this is very different from the `unreachable!()` macro: Unlike the
|
||
/// macro, which panics when it is executed, it is *undefined behavior* to
|
||
/// reach code marked with this function.
|
||
///
|
||
/// The stabilized version of this intrinsic is [`core::hint::unreachable_unchecked`](crate::hint::unreachable_unchecked).
|
||
#[rustc_const_unstable(feature = "const_unreachable_unchecked", issue = "53188")]
|
||
pub fn unreachable() -> !;
|
||
|
||
/// Informs the optimizer that a condition is always true.
|
||
/// If the condition is false, the behavior is undefined.
|
||
///
|
||
/// No code is generated for this intrinsic, but the optimizer will try
|
||
/// to preserve it (and its condition) between passes, which may interfere
|
||
/// with optimization of surrounding code and reduce performance. It should
|
||
/// not be used if the invariant can be discovered by the optimizer on its
|
||
/// own, or if it does not enable any significant optimizations.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
#[rustc_const_unstable(feature = "const_assume", issue = "76972")]
|
||
pub fn assume(b: bool);
|
||
|
||
/// Hints to the compiler that branch condition is likely to be true.
|
||
/// Returns the value passed to it.
|
||
///
|
||
/// Any use other than with `if` statements will probably not have an effect.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
#[rustc_const_unstable(feature = "const_likely", issue = "none")]
|
||
pub fn likely(b: bool) -> bool;
|
||
|
||
/// Hints to the compiler that branch condition is likely to be false.
|
||
/// Returns the value passed to it.
|
||
///
|
||
/// Any use other than with `if` statements will probably not have an effect.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
#[rustc_const_unstable(feature = "const_likely", issue = "none")]
|
||
pub fn unlikely(b: bool) -> bool;
|
||
|
||
/// Executes a breakpoint trap, for inspection by a debugger.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn breakpoint();
|
||
|
||
/// The size of a type in bytes.
|
||
///
|
||
/// More specifically, this is the offset in bytes between successive
|
||
/// items of the same type, including alignment padding.
|
||
///
|
||
/// The stabilized version of this intrinsic is [`core::mem::size_of`](crate::mem::size_of).
|
||
#[rustc_const_stable(feature = "const_size_of", since = "1.40.0")]
|
||
pub fn size_of<T>() -> usize;
|
||
|
||
/// Moves a value to an uninitialized memory location.
|
||
///
|
||
/// Drop glue is not run on the destination.
|
||
///
|
||
/// The stabilized version of this intrinsic is [`core::ptr::write`](crate::ptr::write).
|
||
pub fn move_val_init<T>(dst: *mut T, src: T);
|
||
|
||
/// The minimum alignment of a type.
|
||
///
|
||
/// The stabilized version of this intrinsic is [`core::mem::align_of`](crate::mem::align_of).
|
||
#[rustc_const_stable(feature = "const_min_align_of", since = "1.40.0")]
|
||
pub fn min_align_of<T>() -> usize;
|
||
/// The preferred alignment of a type.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
#[rustc_const_unstable(feature = "const_pref_align_of", issue = "none")]
|
||
pub fn pref_align_of<T>() -> usize;
|
||
|
||
/// The size of the referenced value in bytes.
|
||
///
|
||
/// The stabilized version of this intrinsic is [`mem::size_of_val`].
|
||
#[rustc_const_unstable(feature = "const_size_of_val", issue = "46571")]
|
||
pub fn size_of_val<T: ?Sized>(_: *const T) -> usize;
|
||
/// The required alignment of the referenced value.
|
||
///
|
||
/// The stabilized version of this intrinsic is [`core::mem::align_of_val`](crate::mem::align_of_val).
|
||
#[rustc_const_unstable(feature = "const_align_of_val", issue = "46571")]
|
||
pub fn min_align_of_val<T: ?Sized>(_: *const T) -> usize;
|
||
|
||
/// Gets a static string slice containing the name of a type.
|
||
///
|
||
/// The stabilized version of this intrinsic is [`core::any::type_name`](crate::any::type_name).
|
||
#[rustc_const_unstable(feature = "const_type_name", issue = "63084")]
|
||
pub fn type_name<T: ?Sized>() -> &'static str;
|
||
|
||
/// Gets an identifier which is globally unique to the specified type. This
|
||
/// function will return the same value for a type regardless of whichever
|
||
/// crate it is invoked in.
|
||
///
|
||
/// The stabilized version of this intrinsic is [`core::any::TypeId::of`](crate::any::TypeId::of).
|
||
#[rustc_const_unstable(feature = "const_type_id", issue = "77125")]
|
||
pub fn type_id<T: ?Sized + 'static>() -> u64;
|
||
|
||
/// A guard for unsafe functions that cannot ever be executed if `T` is uninhabited:
|
||
/// This will statically either panic, or do nothing.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
#[rustc_const_unstable(feature = "const_assert_type", issue = "none")]
|
||
pub fn assert_inhabited<T>();
|
||
|
||
/// A guard for unsafe functions that cannot ever be executed if `T` does not permit
|
||
/// zero-initialization: This will statically either panic, or do nothing.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn assert_zero_valid<T>();
|
||
|
||
/// A guard for unsafe functions that cannot ever be executed if `T` has invalid
|
||
/// bit patterns: This will statically either panic, or do nothing.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn assert_uninit_valid<T>();
|
||
|
||
/// Gets a reference to a static `Location` indicating where it was called.
|
||
///
|
||
/// Consider using [`core::panic::Location::caller`](crate::panic::Location::caller) instead.
|
||
#[rustc_const_unstable(feature = "const_caller_location", issue = "76156")]
|
||
pub fn caller_location() -> &'static crate::panic::Location<'static>;
|
||
|
||
/// Moves a value out of scope without running drop glue.
|
||
///
|
||
/// This exists solely for [`mem::forget_unsized`]; normal `forget` uses
|
||
/// `ManuallyDrop` instead.
|
||
pub fn forget<T: ?Sized>(_: T);
|
||
|
||
/// Reinterprets the bits of a value of one type as another type.
|
||
///
|
||
/// Both types must have the same size. Neither the original, nor the result,
|
||
/// may be an [invalid value](../../nomicon/what-unsafe-does.html).
|
||
///
|
||
/// `transmute` is semantically equivalent to a bitwise move of one type
|
||
/// into another. It copies the bits from the source value into the
|
||
/// destination value, then forgets the original. It's equivalent to C's
|
||
/// `memcpy` under the hood, just like `transmute_copy`.
|
||
///
|
||
/// `transmute` is **incredibly** unsafe. There are a vast number of ways to
|
||
/// cause [undefined behavior][ub] with this function. `transmute` should be
|
||
/// the absolute last resort.
|
||
///
|
||
/// The [nomicon](../../nomicon/transmutes.html) has additional
|
||
/// documentation.
|
||
///
|
||
/// [ub]: ../../reference/behavior-considered-undefined.html
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// There are a few things that `transmute` is really useful for.
|
||
///
|
||
/// Turning a pointer into a function pointer. This is *not* portable to
|
||
/// machines where function pointers and data pointers have different sizes.
|
||
///
|
||
/// ```
|
||
/// fn foo() -> i32 {
|
||
/// 0
|
||
/// }
|
||
/// let pointer = foo as *const ();
|
||
/// let function = unsafe {
|
||
/// std::mem::transmute::<*const (), fn() -> i32>(pointer)
|
||
/// };
|
||
/// assert_eq!(function(), 0);
|
||
/// ```
|
||
///
|
||
/// Extending a lifetime, or shortening an invariant lifetime. This is
|
||
/// advanced, very unsafe Rust!
|
||
///
|
||
/// ```
|
||
/// struct R<'a>(&'a i32);
|
||
/// unsafe fn extend_lifetime<'b>(r: R<'b>) -> R<'static> {
|
||
/// std::mem::transmute::<R<'b>, R<'static>>(r)
|
||
/// }
|
||
///
|
||
/// unsafe fn shorten_invariant_lifetime<'b, 'c>(r: &'b mut R<'static>)
|
||
/// -> &'b mut R<'c> {
|
||
/// std::mem::transmute::<&'b mut R<'static>, &'b mut R<'c>>(r)
|
||
/// }
|
||
/// ```
|
||
///
|
||
/// # Alternatives
|
||
///
|
||
/// Don't despair: many uses of `transmute` can be achieved through other means.
|
||
/// Below are common applications of `transmute` which can be replaced with safer
|
||
/// constructs.
|
||
///
|
||
/// Turning raw bytes(`&[u8]`) to `u32`, `f64`, etc.:
|
||
///
|
||
/// ```
|
||
/// let raw_bytes = [0x78, 0x56, 0x34, 0x12];
|
||
///
|
||
/// let num = unsafe {
|
||
/// std::mem::transmute::<[u8; 4], u32>(raw_bytes)
|
||
/// };
|
||
///
|
||
/// // use `u32::from_ne_bytes` instead
|
||
/// let num = u32::from_ne_bytes(raw_bytes);
|
||
/// // or use `u32::from_le_bytes` or `u32::from_be_bytes` to specify the endianness
|
||
/// let num = u32::from_le_bytes(raw_bytes);
|
||
/// assert_eq!(num, 0x12345678);
|
||
/// let num = u32::from_be_bytes(raw_bytes);
|
||
/// assert_eq!(num, 0x78563412);
|
||
/// ```
|
||
///
|
||
/// Turning a pointer into a `usize`:
|
||
///
|
||
/// ```
|
||
/// let ptr = &0;
|
||
/// let ptr_num_transmute = unsafe {
|
||
/// std::mem::transmute::<&i32, usize>(ptr)
|
||
/// };
|
||
///
|
||
/// // Use an `as` cast instead
|
||
/// let ptr_num_cast = ptr as *const i32 as usize;
|
||
/// ```
|
||
///
|
||
/// Turning a `*mut T` into an `&mut T`:
|
||
///
|
||
/// ```
|
||
/// let ptr: *mut i32 = &mut 0;
|
||
/// let ref_transmuted = unsafe {
|
||
/// std::mem::transmute::<*mut i32, &mut i32>(ptr)
|
||
/// };
|
||
///
|
||
/// // Use a reborrow instead
|
||
/// let ref_casted = unsafe { &mut *ptr };
|
||
/// ```
|
||
///
|
||
/// Turning an `&mut T` into an `&mut U`:
|
||
///
|
||
/// ```
|
||
/// let ptr = &mut 0;
|
||
/// let val_transmuted = unsafe {
|
||
/// std::mem::transmute::<&mut i32, &mut u32>(ptr)
|
||
/// };
|
||
///
|
||
/// // Now, put together `as` and reborrowing - note the chaining of `as`
|
||
/// // `as` is not transitive
|
||
/// let val_casts = unsafe { &mut *(ptr as *mut i32 as *mut u32) };
|
||
/// ```
|
||
///
|
||
/// Turning an `&str` into an `&[u8]`:
|
||
///
|
||
/// ```
|
||
/// // this is not a good way to do this.
|
||
/// let slice = unsafe { std::mem::transmute::<&str, &[u8]>("Rust") };
|
||
/// assert_eq!(slice, &[82, 117, 115, 116]);
|
||
///
|
||
/// // You could use `str::as_bytes`
|
||
/// let slice = "Rust".as_bytes();
|
||
/// assert_eq!(slice, &[82, 117, 115, 116]);
|
||
///
|
||
/// // Or, just use a byte string, if you have control over the string
|
||
/// // literal
|
||
/// assert_eq!(b"Rust", &[82, 117, 115, 116]);
|
||
/// ```
|
||
///
|
||
/// Turning a `Vec<&T>` into a `Vec<Option<&T>>`:
|
||
///
|
||
/// ```
|
||
/// let store = [0, 1, 2, 3];
|
||
/// let v_orig = store.iter().collect::<Vec<&i32>>();
|
||
///
|
||
/// // clone the vector as we will reuse them later
|
||
/// let v_clone = v_orig.clone();
|
||
///
|
||
/// // Using transmute: this relies on the unspecified data layout of `Vec`, which is a
|
||
/// // bad idea and could cause Undefined Behavior.
|
||
/// // However, it is no-copy.
|
||
/// let v_transmuted = unsafe {
|
||
/// std::mem::transmute::<Vec<&i32>, Vec<Option<&i32>>>(v_clone)
|
||
/// };
|
||
///
|
||
/// let v_clone = v_orig.clone();
|
||
///
|
||
/// // This is the suggested, safe way.
|
||
/// // It does copy the entire vector, though, into a new array.
|
||
/// let v_collected = v_clone.into_iter()
|
||
/// .map(Some)
|
||
/// .collect::<Vec<Option<&i32>>>();
|
||
///
|
||
/// let v_clone = v_orig.clone();
|
||
///
|
||
/// // The no-copy, unsafe way, still using transmute, but not relying on the data layout.
|
||
/// // Like the first approach, this reuses the `Vec` internals.
|
||
/// // Therefore, the new inner type must have the
|
||
/// // exact same size, *and the same alignment*, as the old type.
|
||
/// // The same caveats exist for this method as transmute, for
|
||
/// // the original inner type (`&i32`) to the converted inner type
|
||
/// // (`Option<&i32>`), so read the nomicon pages linked above and also
|
||
/// // consult the [`from_raw_parts`] documentation.
|
||
/// let v_from_raw = unsafe {
|
||
// FIXME Update this when vec_into_raw_parts is stabilized
|
||
/// // Ensure the original vector is not dropped.
|
||
/// let mut v_clone = std::mem::ManuallyDrop::new(v_clone);
|
||
/// Vec::from_raw_parts(v_clone.as_mut_ptr() as *mut Option<&i32>,
|
||
/// v_clone.len(),
|
||
/// v_clone.capacity())
|
||
/// };
|
||
/// ```
|
||
///
|
||
/// [`from_raw_parts`]: ../../std/vec/struct.Vec.html#method.from_raw_parts
|
||
///
|
||
/// Implementing `split_at_mut`:
|
||
///
|
||
/// ```
|
||
/// use std::{slice, mem};
|
||
///
|
||
/// // There are multiple ways to do this, and there are multiple problems
|
||
/// // with the following (transmute) way.
|
||
/// fn split_at_mut_transmute<T>(slice: &mut [T], mid: usize)
|
||
/// -> (&mut [T], &mut [T]) {
|
||
/// let len = slice.len();
|
||
/// assert!(mid <= len);
|
||
/// unsafe {
|
||
/// let slice2 = mem::transmute::<&mut [T], &mut [T]>(slice);
|
||
/// // first: transmute is not type safe; all it checks is that T and
|
||
/// // U are of the same size. Second, right here, you have two
|
||
/// // mutable references pointing to the same memory.
|
||
/// (&mut slice[0..mid], &mut slice2[mid..len])
|
||
/// }
|
||
/// }
|
||
///
|
||
/// // This gets rid of the type safety problems; `&mut *` will *only* give
|
||
/// // you an `&mut T` from an `&mut T` or `*mut T`.
|
||
/// fn split_at_mut_casts<T>(slice: &mut [T], mid: usize)
|
||
/// -> (&mut [T], &mut [T]) {
|
||
/// let len = slice.len();
|
||
/// assert!(mid <= len);
|
||
/// unsafe {
|
||
/// let slice2 = &mut *(slice as *mut [T]);
|
||
/// // however, you still have two mutable references pointing to
|
||
/// // the same memory.
|
||
/// (&mut slice[0..mid], &mut slice2[mid..len])
|
||
/// }
|
||
/// }
|
||
///
|
||
/// // This is how the standard library does it. This is the best method, if
|
||
/// // you need to do something like this
|
||
/// fn split_at_stdlib<T>(slice: &mut [T], mid: usize)
|
||
/// -> (&mut [T], &mut [T]) {
|
||
/// let len = slice.len();
|
||
/// assert!(mid <= len);
|
||
/// unsafe {
|
||
/// let ptr = slice.as_mut_ptr();
|
||
/// // This now has three mutable references pointing at the same
|
||
/// // memory. `slice`, the rvalue ret.0, and the rvalue ret.1.
|
||
/// // `slice` is never used after `let ptr = ...`, and so one can
|
||
/// // treat it as "dead", and therefore, you only have two real
|
||
/// // mutable slices.
|
||
/// (slice::from_raw_parts_mut(ptr, mid),
|
||
/// slice::from_raw_parts_mut(ptr.add(mid), len - mid))
|
||
/// }
|
||
/// }
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
// NOTE: While this makes the intrinsic const stable, we have some custom code in const fn
|
||
// checks that prevent its use within `const fn`.
|
||
#[rustc_const_stable(feature = "const_transmute", since = "1.46.0")]
|
||
#[rustc_diagnostic_item = "transmute"]
|
||
pub fn transmute<T, U>(e: T) -> U;
|
||
|
||
/// Returns `true` if the actual type given as `T` requires drop
|
||
/// glue; returns `false` if the actual type provided for `T`
|
||
/// implements `Copy`.
|
||
///
|
||
/// If the actual type neither requires drop glue nor implements
|
||
/// `Copy`, then the return value of this function is unspecified.
|
||
///
|
||
/// The stabilized version of this intrinsic is [`mem::needs_drop`](crate::mem::needs_drop).
|
||
#[rustc_const_stable(feature = "const_needs_drop", since = "1.40.0")]
|
||
pub fn needs_drop<T>() -> bool;
|
||
|
||
/// Calculates the offset from a pointer.
|
||
///
|
||
/// This is implemented as an intrinsic to avoid converting to and from an
|
||
/// integer, since the conversion would throw away aliasing information.
|
||
///
|
||
/// # Safety
|
||
///
|
||
/// Both the starting and resulting pointer must be either in bounds or one
|
||
/// byte past the end of an allocated object. If either pointer is out of
|
||
/// bounds or arithmetic overflow occurs then any further use of the
|
||
/// returned value will result in undefined behavior.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`std::pointer::offset`](../../std/primitive.pointer.html#method.offset).
|
||
#[must_use = "returns a new pointer rather than modifying its argument"]
|
||
#[rustc_const_unstable(feature = "const_ptr_offset", issue = "71499")]
|
||
pub fn offset<T>(dst: *const T, offset: isize) -> *const T;
|
||
|
||
/// Calculates the offset from a pointer, potentially wrapping.
|
||
///
|
||
/// This is implemented as an intrinsic to avoid converting to and from an
|
||
/// integer, since the conversion inhibits certain optimizations.
|
||
///
|
||
/// # Safety
|
||
///
|
||
/// Unlike the `offset` intrinsic, this intrinsic does not restrict the
|
||
/// resulting pointer to point into or one byte past the end of an allocated
|
||
/// object, and it wraps with two's complement arithmetic. The resulting
|
||
/// value is not necessarily valid to be used to actually access memory.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`std::pointer::wrapping_offset`](../../std/primitive.pointer.html#method.wrapping_offset).
|
||
#[must_use = "returns a new pointer rather than modifying its argument"]
|
||
#[rustc_const_unstable(feature = "const_ptr_offset", issue = "71499")]
|
||
pub fn arith_offset<T>(dst: *const T, offset: isize) -> *const T;
|
||
|
||
/// Equivalent to the appropriate `llvm.memcpy.p0i8.0i8.*` intrinsic, with
|
||
/// a size of `count` * `size_of::<T>()` and an alignment of
|
||
/// `min_align_of::<T>()`
|
||
///
|
||
/// The volatile parameter is set to `true`, so it will not be optimized out
|
||
/// unless size is equal to zero.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn volatile_copy_nonoverlapping_memory<T>(dst: *mut T, src: *const T, count: usize);
|
||
/// Equivalent to the appropriate `llvm.memmove.p0i8.0i8.*` intrinsic, with
|
||
/// a size of `count * size_of::<T>()` and an alignment of
|
||
/// `min_align_of::<T>()`
|
||
///
|
||
/// The volatile parameter is set to `true`, so it will not be optimized out
|
||
/// unless size is equal to zero.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn volatile_copy_memory<T>(dst: *mut T, src: *const T, count: usize);
|
||
/// Equivalent to the appropriate `llvm.memset.p0i8.*` intrinsic, with a
|
||
/// size of `count * size_of::<T>()` and an alignment of
|
||
/// `min_align_of::<T>()`.
|
||
///
|
||
/// The volatile parameter is set to `true`, so it will not be optimized out
|
||
/// unless size is equal to zero.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn volatile_set_memory<T>(dst: *mut T, val: u8, count: usize);
|
||
|
||
/// Performs a volatile load from the `src` pointer.
|
||
///
|
||
/// The stabilized version of this intrinsic is [`core::ptr::read_volatile`](crate::ptr::read_volatile).
|
||
pub fn volatile_load<T>(src: *const T) -> T;
|
||
/// Performs a volatile store to the `dst` pointer.
|
||
///
|
||
/// The stabilized version of this intrinsic is [`core::ptr::write_volatile`](crate::ptr::write_volatile).
|
||
pub fn volatile_store<T>(dst: *mut T, val: T);
|
||
|
||
/// Performs a volatile load from the `src` pointer
|
||
/// The pointer is not required to be aligned.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn unaligned_volatile_load<T>(src: *const T) -> T;
|
||
/// Performs a volatile store to the `dst` pointer.
|
||
/// The pointer is not required to be aligned.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn unaligned_volatile_store<T>(dst: *mut T, val: T);
|
||
|
||
/// Returns the square root of an `f32`
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::sqrt`](../../std/primitive.f32.html#method.sqrt)
|
||
pub fn sqrtf32(x: f32) -> f32;
|
||
/// Returns the square root of an `f64`
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::sqrt`](../../std/primitive.f64.html#method.sqrt)
|
||
pub fn sqrtf64(x: f64) -> f64;
|
||
|
||
/// Raises an `f32` to an integer power.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::powi`](../../std/primitive.f32.html#method.powi)
|
||
pub fn powif32(a: f32, x: i32) -> f32;
|
||
/// Raises an `f64` to an integer power.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::powi`](../../std/primitive.f64.html#method.powi)
|
||
pub fn powif64(a: f64, x: i32) -> f64;
|
||
|
||
/// Returns the sine of an `f32`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::sin`](../../std/primitive.f32.html#method.sin)
|
||
pub fn sinf32(x: f32) -> f32;
|
||
/// Returns the sine of an `f64`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::sin`](../../std/primitive.f64.html#method.sin)
|
||
pub fn sinf64(x: f64) -> f64;
|
||
|
||
/// Returns the cosine of an `f32`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::cos`](../../std/primitive.f32.html#method.cos)
|
||
pub fn cosf32(x: f32) -> f32;
|
||
/// Returns the cosine of an `f64`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::cos`](../../std/primitive.f64.html#method.cos)
|
||
pub fn cosf64(x: f64) -> f64;
|
||
|
||
/// Raises an `f32` to an `f32` power.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::powf`](../../std/primitive.f32.html#method.powf)
|
||
pub fn powf32(a: f32, x: f32) -> f32;
|
||
/// Raises an `f64` to an `f64` power.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::powf`](../../std/primitive.f64.html#method.powf)
|
||
pub fn powf64(a: f64, x: f64) -> f64;
|
||
|
||
/// Returns the exponential of an `f32`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::exp`](../../std/primitive.f32.html#method.exp)
|
||
pub fn expf32(x: f32) -> f32;
|
||
/// Returns the exponential of an `f64`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::exp`](../../std/primitive.f64.html#method.exp)
|
||
pub fn expf64(x: f64) -> f64;
|
||
|
||
/// Returns 2 raised to the power of an `f32`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::exp2`](../../std/primitive.f32.html#method.exp2)
|
||
pub fn exp2f32(x: f32) -> f32;
|
||
/// Returns 2 raised to the power of an `f64`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::exp2`](../../std/primitive.f64.html#method.exp2)
|
||
pub fn exp2f64(x: f64) -> f64;
|
||
|
||
/// Returns the natural logarithm of an `f32`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::ln`](../../std/primitive.f32.html#method.ln)
|
||
pub fn logf32(x: f32) -> f32;
|
||
/// Returns the natural logarithm of an `f64`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::ln`](../../std/primitive.f64.html#method.ln)
|
||
pub fn logf64(x: f64) -> f64;
|
||
|
||
/// Returns the base 10 logarithm of an `f32`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::log10`](../../std/primitive.f32.html#method.log10)
|
||
pub fn log10f32(x: f32) -> f32;
|
||
/// Returns the base 10 logarithm of an `f64`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::log10`](../../std/primitive.f64.html#method.log10)
|
||
pub fn log10f64(x: f64) -> f64;
|
||
|
||
/// Returns the base 2 logarithm of an `f32`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::log2`](../../std/primitive.f32.html#method.log2)
|
||
pub fn log2f32(x: f32) -> f32;
|
||
/// Returns the base 2 logarithm of an `f64`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::log2`](../../std/primitive.f64.html#method.log2)
|
||
pub fn log2f64(x: f64) -> f64;
|
||
|
||
/// Returns `a * b + c` for `f32` values.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::mul_add`](../../std/primitive.f32.html#method.mul_add)
|
||
pub fn fmaf32(a: f32, b: f32, c: f32) -> f32;
|
||
/// Returns `a * b + c` for `f64` values.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::mul_add`](../../std/primitive.f64.html#method.mul_add)
|
||
pub fn fmaf64(a: f64, b: f64, c: f64) -> f64;
|
||
|
||
/// Returns the absolute value of an `f32`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::abs`](../../std/primitive.f32.html#method.abs)
|
||
pub fn fabsf32(x: f32) -> f32;
|
||
/// Returns the absolute value of an `f64`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::abs`](../../std/primitive.f64.html#method.abs)
|
||
pub fn fabsf64(x: f64) -> f64;
|
||
|
||
/// Returns the minimum of two `f32` values.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::min`]
|
||
pub fn minnumf32(x: f32, y: f32) -> f32;
|
||
/// Returns the minimum of two `f64` values.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::min`]
|
||
pub fn minnumf64(x: f64, y: f64) -> f64;
|
||
/// Returns the maximum of two `f32` values.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::max`]
|
||
pub fn maxnumf32(x: f32, y: f32) -> f32;
|
||
/// Returns the maximum of two `f64` values.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::max`]
|
||
pub fn maxnumf64(x: f64, y: f64) -> f64;
|
||
|
||
/// Copies the sign from `y` to `x` for `f32` values.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::copysign`](../../std/primitive.f32.html#method.copysign)
|
||
pub fn copysignf32(x: f32, y: f32) -> f32;
|
||
/// Copies the sign from `y` to `x` for `f64` values.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::copysign`](../../std/primitive.f64.html#method.copysign)
|
||
pub fn copysignf64(x: f64, y: f64) -> f64;
|
||
|
||
/// Returns the largest integer less than or equal to an `f32`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::floor`](../../std/primitive.f32.html#method.floor)
|
||
pub fn floorf32(x: f32) -> f32;
|
||
/// Returns the largest integer less than or equal to an `f64`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::floor`](../../std/primitive.f64.html#method.floor)
|
||
pub fn floorf64(x: f64) -> f64;
|
||
|
||
/// Returns the smallest integer greater than or equal to an `f32`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::ceil`](../../std/primitive.f32.html#method.ceil)
|
||
pub fn ceilf32(x: f32) -> f32;
|
||
/// Returns the smallest integer greater than or equal to an `f64`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::ceil`](../../std/primitive.f64.html#method.ceil)
|
||
pub fn ceilf64(x: f64) -> f64;
|
||
|
||
/// Returns the integer part of an `f32`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::trunc`](../../std/primitive.f32.html#method.trunc)
|
||
pub fn truncf32(x: f32) -> f32;
|
||
/// Returns the integer part of an `f64`.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::trunc`](../../std/primitive.f64.html#method.trunc)
|
||
pub fn truncf64(x: f64) -> f64;
|
||
|
||
/// Returns the nearest integer to an `f32`. May raise an inexact floating-point exception
|
||
/// if the argument is not an integer.
|
||
pub fn rintf32(x: f32) -> f32;
|
||
/// Returns the nearest integer to an `f64`. May raise an inexact floating-point exception
|
||
/// if the argument is not an integer.
|
||
pub fn rintf64(x: f64) -> f64;
|
||
|
||
/// Returns the nearest integer to an `f32`.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn nearbyintf32(x: f32) -> f32;
|
||
/// Returns the nearest integer to an `f64`.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn nearbyintf64(x: f64) -> f64;
|
||
|
||
/// Returns the nearest integer to an `f32`. Rounds half-way cases away from zero.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f32::round`](../../std/primitive.f32.html#method.round)
|
||
pub fn roundf32(x: f32) -> f32;
|
||
/// Returns the nearest integer to an `f64`. Rounds half-way cases away from zero.
|
||
///
|
||
/// The stabilized version of this intrinsic is
|
||
/// [`f64::round`](../../std/primitive.f64.html#method.round)
|
||
pub fn roundf64(x: f64) -> f64;
|
||
|
||
/// Float addition that allows optimizations based on algebraic rules.
|
||
/// May assume inputs are finite.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn fadd_fast<T: Copy>(a: T, b: T) -> T;
|
||
|
||
/// Float subtraction that allows optimizations based on algebraic rules.
|
||
/// May assume inputs are finite.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn fsub_fast<T: Copy>(a: T, b: T) -> T;
|
||
|
||
/// Float multiplication that allows optimizations based on algebraic rules.
|
||
/// May assume inputs are finite.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn fmul_fast<T: Copy>(a: T, b: T) -> T;
|
||
|
||
/// Float division that allows optimizations based on algebraic rules.
|
||
/// May assume inputs are finite.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn fdiv_fast<T: Copy>(a: T, b: T) -> T;
|
||
|
||
/// Float remainder that allows optimizations based on algebraic rules.
|
||
/// May assume inputs are finite.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn frem_fast<T: Copy>(a: T, b: T) -> T;
|
||
|
||
/// Convert with LLVM’s fptoui/fptosi, which may return undef for values out of range
|
||
/// (<https://github.com/rust-lang/rust/issues/10184>)
|
||
///
|
||
/// Stabilized as [`f32::to_int_unchecked`] and [`f64::to_int_unchecked`].
|
||
pub fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
|
||
|
||
/// Returns the number of bits set in an integer type `T`
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `count_ones` method. For example,
|
||
/// [`u32::count_ones`]
|
||
#[rustc_const_stable(feature = "const_ctpop", since = "1.40.0")]
|
||
pub fn ctpop<T: Copy>(x: T) -> T;
|
||
|
||
/// Returns the number of leading unset bits (zeroes) in an integer type `T`.
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `leading_zeros` method. For example,
|
||
/// [`u32::leading_zeros`]
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// #![feature(core_intrinsics)]
|
||
///
|
||
/// use std::intrinsics::ctlz;
|
||
///
|
||
/// let x = 0b0001_1100_u8;
|
||
/// let num_leading = ctlz(x);
|
||
/// assert_eq!(num_leading, 3);
|
||
/// ```
|
||
///
|
||
/// An `x` with value `0` will return the bit width of `T`.
|
||
///
|
||
/// ```
|
||
/// #![feature(core_intrinsics)]
|
||
///
|
||
/// use std::intrinsics::ctlz;
|
||
///
|
||
/// let x = 0u16;
|
||
/// let num_leading = ctlz(x);
|
||
/// assert_eq!(num_leading, 16);
|
||
/// ```
|
||
#[rustc_const_stable(feature = "const_ctlz", since = "1.40.0")]
|
||
pub fn ctlz<T: Copy>(x: T) -> T;
|
||
|
||
/// Like `ctlz`, but extra-unsafe as it returns `undef` when
|
||
/// given an `x` with value `0`.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// #![feature(core_intrinsics)]
|
||
///
|
||
/// use std::intrinsics::ctlz_nonzero;
|
||
///
|
||
/// let x = 0b0001_1100_u8;
|
||
/// let num_leading = unsafe { ctlz_nonzero(x) };
|
||
/// assert_eq!(num_leading, 3);
|
||
/// ```
|
||
#[rustc_const_stable(feature = "constctlz", since = "1.50.0")]
|
||
pub fn ctlz_nonzero<T: Copy>(x: T) -> T;
|
||
|
||
/// Returns the number of trailing unset bits (zeroes) in an integer type `T`.
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `trailing_zeros` method. For example,
|
||
/// [`u32::trailing_zeros`]
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// #![feature(core_intrinsics)]
|
||
///
|
||
/// use std::intrinsics::cttz;
|
||
///
|
||
/// let x = 0b0011_1000_u8;
|
||
/// let num_trailing = cttz(x);
|
||
/// assert_eq!(num_trailing, 3);
|
||
/// ```
|
||
///
|
||
/// An `x` with value `0` will return the bit width of `T`:
|
||
///
|
||
/// ```
|
||
/// #![feature(core_intrinsics)]
|
||
///
|
||
/// use std::intrinsics::cttz;
|
||
///
|
||
/// let x = 0u16;
|
||
/// let num_trailing = cttz(x);
|
||
/// assert_eq!(num_trailing, 16);
|
||
/// ```
|
||
#[rustc_const_stable(feature = "const_cttz", since = "1.40.0")]
|
||
pub fn cttz<T: Copy>(x: T) -> T;
|
||
|
||
/// Like `cttz`, but extra-unsafe as it returns `undef` when
|
||
/// given an `x` with value `0`.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// #![feature(core_intrinsics)]
|
||
///
|
||
/// use std::intrinsics::cttz_nonzero;
|
||
///
|
||
/// let x = 0b0011_1000_u8;
|
||
/// let num_trailing = unsafe { cttz_nonzero(x) };
|
||
/// assert_eq!(num_trailing, 3);
|
||
/// ```
|
||
#[rustc_const_unstable(feature = "const_cttz", issue = "none")]
|
||
pub fn cttz_nonzero<T: Copy>(x: T) -> T;
|
||
|
||
/// Reverses the bytes in an integer type `T`.
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `swap_bytes` method. For example,
|
||
/// [`u32::swap_bytes`]
|
||
#[rustc_const_stable(feature = "const_bswap", since = "1.40.0")]
|
||
pub fn bswap<T: Copy>(x: T) -> T;
|
||
|
||
/// Reverses the bits in an integer type `T`.
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `reverse_bits` method. For example,
|
||
/// [`u32::reverse_bits`]
|
||
#[rustc_const_stable(feature = "const_bitreverse", since = "1.40.0")]
|
||
pub fn bitreverse<T: Copy>(x: T) -> T;
|
||
|
||
/// Performs checked integer addition.
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `overflowing_add` method. For example,
|
||
/// [`u32::overflowing_add`]
|
||
#[rustc_const_stable(feature = "const_int_overflow", since = "1.40.0")]
|
||
pub fn add_with_overflow<T: Copy>(x: T, y: T) -> (T, bool);
|
||
|
||
/// Performs checked integer subtraction
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `overflowing_sub` method. For example,
|
||
/// [`u32::overflowing_sub`]
|
||
#[rustc_const_stable(feature = "const_int_overflow", since = "1.40.0")]
|
||
pub fn sub_with_overflow<T: Copy>(x: T, y: T) -> (T, bool);
|
||
|
||
/// Performs checked integer multiplication
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `overflowing_mul` method. For example,
|
||
/// [`u32::overflowing_mul`]
|
||
#[rustc_const_stable(feature = "const_int_overflow", since = "1.40.0")]
|
||
pub fn mul_with_overflow<T: Copy>(x: T, y: T) -> (T, bool);
|
||
|
||
/// Performs an exact division, resulting in undefined behavior where
|
||
/// `x % y != 0` or `y == 0` or `x == T::MIN && y == -1`
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
pub fn exact_div<T: Copy>(x: T, y: T) -> T;
|
||
|
||
/// Performs an unchecked division, resulting in undefined behavior
|
||
/// where `y == 0` or `x == T::MIN && y == -1`
|
||
///
|
||
/// Safe wrappers for this intrinsic are available on the integer
|
||
/// primitives via the `checked_div` method. For example,
|
||
/// [`u32::checked_div`]
|
||
#[rustc_const_unstable(feature = "const_int_unchecked_arith", issue = "none")]
|
||
pub fn unchecked_div<T: Copy>(x: T, y: T) -> T;
|
||
/// Returns the remainder of an unchecked division, resulting in
|
||
/// undefined behavior when `y == 0` or `x == T::MIN && y == -1`
|
||
///
|
||
/// Safe wrappers for this intrinsic are available on the integer
|
||
/// primitives via the `checked_rem` method. For example,
|
||
/// [`u32::checked_rem`]
|
||
#[rustc_const_unstable(feature = "const_int_unchecked_arith", issue = "none")]
|
||
pub fn unchecked_rem<T: Copy>(x: T, y: T) -> T;
|
||
|
||
/// Performs an unchecked left shift, resulting in undefined behavior when
|
||
/// `y < 0` or `y >= N`, where N is the width of T in bits.
|
||
///
|
||
/// Safe wrappers for this intrinsic are available on the integer
|
||
/// primitives via the `checked_shl` method. For example,
|
||
/// [`u32::checked_shl`]
|
||
#[rustc_const_stable(feature = "const_int_unchecked", since = "1.40.0")]
|
||
pub fn unchecked_shl<T: Copy>(x: T, y: T) -> T;
|
||
/// Performs an unchecked right shift, resulting in undefined behavior when
|
||
/// `y < 0` or `y >= N`, where N is the width of T in bits.
|
||
///
|
||
/// Safe wrappers for this intrinsic are available on the integer
|
||
/// primitives via the `checked_shr` method. For example,
|
||
/// [`u32::checked_shr`]
|
||
#[rustc_const_stable(feature = "const_int_unchecked", since = "1.40.0")]
|
||
pub fn unchecked_shr<T: Copy>(x: T, y: T) -> T;
|
||
|
||
/// Returns the result of an unchecked addition, resulting in
|
||
/// undefined behavior when `x + y > T::MAX` or `x + y < T::MIN`.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
#[rustc_const_unstable(feature = "const_int_unchecked_arith", issue = "none")]
|
||
pub fn unchecked_add<T: Copy>(x: T, y: T) -> T;
|
||
|
||
/// Returns the result of an unchecked subtraction, resulting in
|
||
/// undefined behavior when `x - y > T::MAX` or `x - y < T::MIN`.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
#[rustc_const_unstable(feature = "const_int_unchecked_arith", issue = "none")]
|
||
pub fn unchecked_sub<T: Copy>(x: T, y: T) -> T;
|
||
|
||
/// Returns the result of an unchecked multiplication, resulting in
|
||
/// undefined behavior when `x * y > T::MAX` or `x * y < T::MIN`.
|
||
///
|
||
/// This intrinsic does not have a stable counterpart.
|
||
#[rustc_const_unstable(feature = "const_int_unchecked_arith", issue = "none")]
|
||
pub fn unchecked_mul<T: Copy>(x: T, y: T) -> T;
|
||
|
||
/// Performs rotate left.
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `rotate_left` method. For example,
|
||
/// [`u32::rotate_left`]
|
||
#[rustc_const_stable(feature = "const_int_rotate", since = "1.40.0")]
|
||
pub fn rotate_left<T: Copy>(x: T, y: T) -> T;
|
||
|
||
/// Performs rotate right.
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `rotate_right` method. For example,
|
||
/// [`u32::rotate_right`]
|
||
#[rustc_const_stable(feature = "const_int_rotate", since = "1.40.0")]
|
||
pub fn rotate_right<T: Copy>(x: T, y: T) -> T;
|
||
|
||
/// Returns (a + b) mod 2<sup>N</sup>, where N is the width of T in bits.
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `wrapping_add` method. For example,
|
||
/// [`u32::wrapping_add`]
|
||
#[rustc_const_stable(feature = "const_int_wrapping", since = "1.40.0")]
|
||
pub fn wrapping_add<T: Copy>(a: T, b: T) -> T;
|
||
/// Returns (a - b) mod 2<sup>N</sup>, where N is the width of T in bits.
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `wrapping_sub` method. For example,
|
||
/// [`u32::wrapping_sub`]
|
||
#[rustc_const_stable(feature = "const_int_wrapping", since = "1.40.0")]
|
||
pub fn wrapping_sub<T: Copy>(a: T, b: T) -> T;
|
||
/// Returns (a * b) mod 2<sup>N</sup>, where N is the width of T in bits.
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `wrapping_mul` method. For example,
|
||
/// [`u32::wrapping_mul`]
|
||
#[rustc_const_stable(feature = "const_int_wrapping", since = "1.40.0")]
|
||
pub fn wrapping_mul<T: Copy>(a: T, b: T) -> T;
|
||
|
||
/// Computes `a + b`, saturating at numeric bounds.
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `saturating_add` method. For example,
|
||
/// [`u32::saturating_add`]
|
||
#[rustc_const_stable(feature = "const_int_saturating", since = "1.40.0")]
|
||
pub fn saturating_add<T: Copy>(a: T, b: T) -> T;
|
||
/// Computes `a - b`, saturating at numeric bounds.
|
||
///
|
||
/// The stabilized versions of this intrinsic are available on the integer
|
||
/// primitives via the `saturating_sub` method. For example,
|
||
/// [`u32::saturating_sub`]
|
||
#[rustc_const_stable(feature = "const_int_saturating", since = "1.40.0")]
|
||
pub fn saturating_sub<T: Copy>(a: T, b: T) -> T;
|
||
|
||
/// Returns the value of the discriminant for the variant in 'v',
|
||
/// cast to a `u64`; if `T` has no discriminant, returns `0`.
|
||
///
|
||
/// The stabilized version of this intrinsic is [`core::mem::discriminant`](crate::mem::discriminant).
|
||
#[rustc_const_unstable(feature = "const_discriminant", issue = "69821")]
|
||
pub fn discriminant_value<T>(v: &T) -> <T as DiscriminantKind>::Discriminant;
|
||
|
||
/// Returns the number of variants of the type `T` cast to a `usize`;
|
||
/// if `T` has no variants, returns `0`. Uninhabited variants will be counted.
|
||
///
|
||
/// The to-be-stabilized version of this intrinsic is [`mem::variant_count`].
|
||
#[rustc_const_unstable(feature = "variant_count", issue = "73662")]
|
||
pub fn variant_count<T>() -> usize;
|
||
|
||
/// Rust's "try catch" construct which invokes the function pointer `try_fn`
|
||
/// with the data pointer `data`.
|
||
///
|
||
/// The third argument is a function called if a panic occurs. This function
|
||
/// takes the data pointer and a pointer to the target-specific exception
|
||
/// object that was caught. For more information see the compiler's
|
||
/// source as well as std's catch implementation.
|
||
pub fn r#try(try_fn: fn(*mut u8), data: *mut u8, catch_fn: fn(*mut u8, *mut u8)) -> i32;
|
||
|
||
/// Emits a `!nontemporal` store according to LLVM (see their docs).
|
||
/// Probably will never become stable.
|
||
pub fn nontemporal_store<T>(ptr: *mut T, val: T);
|
||
|
||
/// See documentation of `<*const T>::offset_from` for details.
|
||
#[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "41079")]
|
||
pub fn ptr_offset_from<T>(ptr: *const T, base: *const T) -> isize;
|
||
|
||
/// See documentation of `<*const T>::guaranteed_eq` for details.
|
||
#[rustc_const_unstable(feature = "const_raw_ptr_comparison", issue = "53020")]
|
||
pub fn ptr_guaranteed_eq<T>(ptr: *const T, other: *const T) -> bool;
|
||
|
||
/// See documentation of `<*const T>::guaranteed_ne` for details.
|
||
#[rustc_const_unstable(feature = "const_raw_ptr_comparison", issue = "53020")]
|
||
pub fn ptr_guaranteed_ne<T>(ptr: *const T, other: *const T) -> bool;
|
||
|
||
/// Allocate at compile time. Should not be called at runtime.
|
||
#[rustc_const_unstable(feature = "const_heap", issue = "79597")]
|
||
pub fn const_allocate(size: usize, align: usize) -> *mut u8;
|
||
}
|
||
|
||
// Some functions are defined here because they accidentally got made
|
||
// available in this module on stable. See <https://github.com/rust-lang/rust/issues/15702>.
|
||
// (`transmute` also falls into this category, but it cannot be wrapped due to the
|
||
// check that `T` and `U` have the same size.)
|
||
|
||
/// Checks whether `ptr` is properly aligned with respect to
|
||
/// `align_of::<T>()`.
|
||
pub(crate) fn is_aligned_and_not_null<T>(ptr: *const T) -> bool {
|
||
!ptr.is_null() && ptr as usize % mem::align_of::<T>() == 0
|
||
}
|
||
|
||
/// Checks whether the regions of memory starting at `src` and `dst` of size
|
||
/// `count * size_of::<T>()` do *not* overlap.
|
||
pub(crate) fn is_nonoverlapping<T>(src: *const T, dst: *const T, count: usize) -> bool {
|
||
let src_usize = src as usize;
|
||
let dst_usize = dst as usize;
|
||
let size = mem::size_of::<T>().checked_mul(count).unwrap();
|
||
let diff = if src_usize > dst_usize { src_usize - dst_usize } else { dst_usize - src_usize };
|
||
// If the absolute distance between the ptrs is at least as big as the size of the buffer,
|
||
// they do not overlap.
|
||
diff >= size
|
||
}
|
||
|
||
/// Copies `count * size_of::<T>()` bytes from `src` to `dst`. The source
|
||
/// and destination must *not* overlap.
|
||
///
|
||
/// For regions of memory which might overlap, use [`copy`] instead.
|
||
///
|
||
/// `copy_nonoverlapping` is semantically equivalent to C's [`memcpy`], but
|
||
/// with the argument order swapped.
|
||
///
|
||
/// [`memcpy`]: https://en.cppreference.com/w/c/string/byte/memcpy
|
||
///
|
||
/// # Safety
|
||
///
|
||
/// Behavior is undefined if any of the following conditions are violated:
|
||
///
|
||
/// * `src` must be [valid] for reads of `count * size_of::<T>()` bytes.
|
||
///
|
||
/// * `dst` must be [valid] for writes of `count * size_of::<T>()` bytes.
|
||
///
|
||
/// * Both `src` and `dst` must be properly aligned.
|
||
///
|
||
/// * The region of memory beginning at `src` with a size of `count *
|
||
/// size_of::<T>()` bytes must *not* overlap with the region of memory
|
||
/// beginning at `dst` with the same size.
|
||
///
|
||
/// Like [`read`], `copy_nonoverlapping` creates a bitwise copy of `T`, regardless of
|
||
/// whether `T` is [`Copy`]. If `T` is not [`Copy`], using *both* the values
|
||
/// in the region beginning at `*src` and the region beginning at `*dst` can
|
||
/// [violate memory safety][read-ownership].
|
||
///
|
||
/// Note that even if the effectively copied size (`count * size_of::<T>()`) is
|
||
/// `0`, the pointers must be non-NULL and properly aligned.
|
||
///
|
||
/// [`read`]: crate::ptr::read
|
||
/// [read-ownership]: crate::ptr::read#ownership-of-the-returned-value
|
||
/// [valid]: crate::ptr#safety
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Manually implement [`Vec::append`]:
|
||
///
|
||
/// ```
|
||
/// use std::ptr;
|
||
///
|
||
/// /// Moves all the elements of `src` into `dst`, leaving `src` empty.
|
||
/// fn append<T>(dst: &mut Vec<T>, src: &mut Vec<T>) {
|
||
/// let src_len = src.len();
|
||
/// let dst_len = dst.len();
|
||
///
|
||
/// // Ensure that `dst` has enough capacity to hold all of `src`.
|
||
/// dst.reserve(src_len);
|
||
///
|
||
/// unsafe {
|
||
/// // The call to offset is always safe because `Vec` will never
|
||
/// // allocate more than `isize::MAX` bytes.
|
||
/// let dst_ptr = dst.as_mut_ptr().offset(dst_len as isize);
|
||
/// let src_ptr = src.as_ptr();
|
||
///
|
||
/// // Truncate `src` without dropping its contents. We do this first,
|
||
/// // to avoid problems in case something further down panics.
|
||
/// src.set_len(0);
|
||
///
|
||
/// // The two regions cannot overlap because mutable references do
|
||
/// // not alias, and two different vectors cannot own the same
|
||
/// // memory.
|
||
/// ptr::copy_nonoverlapping(src_ptr, dst_ptr, src_len);
|
||
///
|
||
/// // Notify `dst` that it now holds the contents of `src`.
|
||
/// dst.set_len(dst_len + src_len);
|
||
/// }
|
||
/// }
|
||
///
|
||
/// let mut a = vec!['r'];
|
||
/// let mut b = vec!['u', 's', 't'];
|
||
///
|
||
/// append(&mut a, &mut b);
|
||
///
|
||
/// assert_eq!(a, &['r', 'u', 's', 't']);
|
||
/// assert!(b.is_empty());
|
||
/// ```
|
||
///
|
||
/// [`Vec::append`]: ../../std/vec/struct.Vec.html#method.append
|
||
#[doc(alias = "memcpy")]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
|
||
#[inline]
|
||
pub const unsafe fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize) {
|
||
extern "rust-intrinsic" {
|
||
fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
|
||
}
|
||
|
||
// FIXME: Perform these checks only at run time
|
||
/*if cfg!(debug_assertions)
|
||
&& !(is_aligned_and_not_null(src)
|
||
&& is_aligned_and_not_null(dst)
|
||
&& is_nonoverlapping(src, dst, count))
|
||
{
|
||
// Not panicking to keep codegen impact smaller.
|
||
abort();
|
||
}*/
|
||
|
||
// SAFETY: the safety contract for `copy_nonoverlapping` must be
|
||
// upheld by the caller.
|
||
unsafe { copy_nonoverlapping(src, dst, count) }
|
||
}
|
||
|
||
/// Copies `count * size_of::<T>()` bytes from `src` to `dst`. The source
|
||
/// and destination may overlap.
|
||
///
|
||
/// If the source and destination will *never* overlap,
|
||
/// [`copy_nonoverlapping`] can be used instead.
|
||
///
|
||
/// `copy` is semantically equivalent to C's [`memmove`], but with the argument
|
||
/// order swapped. Copying takes place as if the bytes were copied from `src`
|
||
/// to a temporary array and then copied from the array to `dst`.
|
||
///
|
||
/// [`memmove`]: https://en.cppreference.com/w/c/string/byte/memmove
|
||
///
|
||
/// # Safety
|
||
///
|
||
/// Behavior is undefined if any of the following conditions are violated:
|
||
///
|
||
/// * `src` must be [valid] for reads of `count * size_of::<T>()` bytes.
|
||
///
|
||
/// * `dst` must be [valid] for writes of `count * size_of::<T>()` bytes.
|
||
///
|
||
/// * Both `src` and `dst` must be properly aligned.
|
||
///
|
||
/// Like [`read`], `copy` creates a bitwise copy of `T`, regardless of
|
||
/// whether `T` is [`Copy`]. If `T` is not [`Copy`], using both the values
|
||
/// in the region beginning at `*src` and the region beginning at `*dst` can
|
||
/// [violate memory safety][read-ownership].
|
||
///
|
||
/// Note that even if the effectively copied size (`count * size_of::<T>()`) is
|
||
/// `0`, the pointers must be non-NULL and properly aligned.
|
||
///
|
||
/// [`read`]: crate::ptr::read
|
||
/// [read-ownership]: crate::ptr::read#ownership-of-the-returned-value
|
||
/// [valid]: crate::ptr#safety
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Efficiently create a Rust vector from an unsafe buffer:
|
||
///
|
||
/// ```
|
||
/// use std::ptr;
|
||
///
|
||
/// /// # Safety
|
||
/// ///
|
||
/// /// * `ptr` must be correctly aligned for its type and non-zero.
|
||
/// /// * `ptr` must be valid for reads of `elts` contiguous elements of type `T`.
|
||
/// /// * Those elements must not be used after calling this function unless `T: Copy`.
|
||
/// # #[allow(dead_code)]
|
||
/// unsafe fn from_buf_raw<T>(ptr: *const T, elts: usize) -> Vec<T> {
|
||
/// let mut dst = Vec::with_capacity(elts);
|
||
///
|
||
/// // SAFETY: Our precondition ensures the source is aligned and valid,
|
||
/// // and `Vec::with_capacity` ensures that we have usable space to write them.
|
||
/// ptr::copy(ptr, dst.as_mut_ptr(), elts);
|
||
///
|
||
/// // SAFETY: We created it with this much capacity earlier,
|
||
/// // and the previous `copy` has initialized these elements.
|
||
/// dst.set_len(elts);
|
||
/// dst
|
||
/// }
|
||
/// ```
|
||
#[doc(alias = "memmove")]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
|
||
#[inline]
|
||
pub const unsafe fn copy<T>(src: *const T, dst: *mut T, count: usize) {
|
||
extern "rust-intrinsic" {
|
||
fn copy<T>(src: *const T, dst: *mut T, count: usize);
|
||
}
|
||
|
||
// FIXME: Perform these checks only at run time
|
||
/*if cfg!(debug_assertions) && !(is_aligned_and_not_null(src) && is_aligned_and_not_null(dst)) {
|
||
// Not panicking to keep codegen impact smaller.
|
||
abort();
|
||
}*/
|
||
|
||
// SAFETY: the safety contract for `copy` must be upheld by the caller.
|
||
unsafe { copy(src, dst, count) }
|
||
}
|
||
|
||
/// Sets `count * size_of::<T>()` bytes of memory starting at `dst` to
|
||
/// `val`.
|
||
///
|
||
/// `write_bytes` is similar to C's [`memset`], but sets `count *
|
||
/// size_of::<T>()` bytes to `val`.
|
||
///
|
||
/// [`memset`]: https://en.cppreference.com/w/c/string/byte/memset
|
||
///
|
||
/// # Safety
|
||
///
|
||
/// Behavior is undefined if any of the following conditions are violated:
|
||
///
|
||
/// * `dst` must be [valid] for writes of `count * size_of::<T>()` bytes.
|
||
///
|
||
/// * `dst` must be properly aligned.
|
||
///
|
||
/// Additionally, the caller must ensure that writing `count *
|
||
/// size_of::<T>()` bytes to the given region of memory results in a valid
|
||
/// value of `T`. Using a region of memory typed as a `T` that contains an
|
||
/// invalid value of `T` is undefined behavior.
|
||
///
|
||
/// Note that even if the effectively copied size (`count * size_of::<T>()`) is
|
||
/// `0`, the pointer must be non-NULL and properly aligned.
|
||
///
|
||
/// [valid]: crate::ptr#safety
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// use std::ptr;
|
||
///
|
||
/// let mut vec = vec![0u32; 4];
|
||
/// unsafe {
|
||
/// let vec_ptr = vec.as_mut_ptr();
|
||
/// ptr::write_bytes(vec_ptr, 0xfe, 2);
|
||
/// }
|
||
/// assert_eq!(vec, [0xfefefefe, 0xfefefefe, 0, 0]);
|
||
/// ```
|
||
///
|
||
/// Creating an invalid value:
|
||
///
|
||
/// ```
|
||
/// use std::ptr;
|
||
///
|
||
/// let mut v = Box::new(0i32);
|
||
///
|
||
/// unsafe {
|
||
/// // Leaks the previously held value by overwriting the `Box<T>` with
|
||
/// // a null pointer.
|
||
/// ptr::write_bytes(&mut v as *mut Box<i32>, 0, 1);
|
||
/// }
|
||
///
|
||
/// // At this point, using or dropping `v` results in undefined behavior.
|
||
/// // drop(v); // ERROR
|
||
///
|
||
/// // Even leaking `v` "uses" it, and hence is undefined behavior.
|
||
/// // mem::forget(v); // ERROR
|
||
///
|
||
/// // In fact, `v` is invalid according to basic type layout invariants, so *any*
|
||
/// // operation touching it is undefined behavior.
|
||
/// // let v2 = v; // ERROR
|
||
///
|
||
/// unsafe {
|
||
/// // Let us instead put in a valid value
|
||
/// ptr::write(&mut v as *mut Box<i32>, Box::new(42i32));
|
||
/// }
|
||
///
|
||
/// // Now the box is fine
|
||
/// assert_eq!(*v, 42);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub unsafe fn write_bytes<T>(dst: *mut T, val: u8, count: usize) {
|
||
extern "rust-intrinsic" {
|
||
fn write_bytes<T>(dst: *mut T, val: u8, count: usize);
|
||
}
|
||
|
||
debug_assert!(is_aligned_and_not_null(dst), "attempt to write to unaligned or null pointer");
|
||
|
||
// SAFETY: the safety contract for `write_bytes` must be upheld by the caller.
|
||
unsafe { write_bytes(dst, val, count) }
|
||
}
|