From 54d024ec507c7033c0ff3c8ad3f22ff1afffcc87 Mon Sep 17 00:00:00 2001 From: Ralf Jung Date: Sat, 24 Feb 2024 15:07:16 +0100 Subject: [PATCH] intrinsics.rs: add some notes on unwinding --- library/core/src/intrinsics.rs | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs index 6fd3895bb9c12..96e667d63c5f3 100644 --- a/library/core/src/intrinsics.rs +++ b/library/core/src/intrinsics.rs @@ -44,6 +44,15 @@ //! * 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`. +//! +//! # Unwinding +//! +//! Rust intrinsics may, in general, unwind. If an intrinsic can never unwind, add the +//! `#[rustc_nounwind]` attribute so that the compiler can make use of this fact. +//! +//! However, even for intrinsics that may unwind, rustc assumes that a Rust intrinsics will never +//! initiate a foreign (non-Rust) unwind, and thus for panic=abort we can always assume that these +//! intrinsics cannot unwind. #![unstable( feature = "core_intrinsics", @@ -692,6 +701,7 @@ extern "rust-intrinsic" { /// 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`]. + #[rustc_nounwind] pub fn atomic_min_acqrel(dst: *mut T, src: T) -> T; /// Minimum with the current value using a signed comparison. ///