From: Miguel Ojeda Date: Sat, 3 Jul 2021 15:30:16 +0000 (+0200) Subject: rust: add `build_error` crate X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=8444e3570a0fc1713a164bcd54df3f0db3bb344a;p=users%2Fjedix%2Flinux-maple.git rust: add `build_error` crate The `build_error` crate provides the `build_error` function which is then used to provide the `build_error!` and the `build_assert!` macros. `build_assert!` is intended to be used when `static_assert!` cannot be used, e.g. when the condition refers to generic parameters or parameters of an inline function. Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Geoffrey Thomas Signed-off-by: Geoffrey Thomas Co-developed-by: Finn Behrens Signed-off-by: Finn Behrens Co-developed-by: Adam Bratschi-Kaye Signed-off-by: Adam Bratschi-Kaye Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: Boqun Feng Signed-off-by: Boqun Feng Co-developed-by: Sumera Priyadarsini Signed-off-by: Sumera Priyadarsini Co-developed-by: Michael Ellerman Signed-off-by: Michael Ellerman Co-developed-by: Sven Van Asbroeck Signed-off-by: Sven Van Asbroeck Co-developed-by: Gary Guo Signed-off-by: Gary Guo Co-developed-by: Boris-Chengbiao Zhou Signed-off-by: Boris-Chengbiao Zhou Co-developed-by: Fox Chen Signed-off-by: Fox Chen Co-developed-by: Ayaan Zaidi Signed-off-by: Ayaan Zaidi Co-developed-by: Douglas Su Signed-off-by: Douglas Su Co-developed-by: Yuki Okushi Signed-off-by: Yuki Okushi Signed-off-by: Miguel Ojeda --- diff --git a/rust/build_error.rs b/rust/build_error.rs new file mode 100644 index 0000000000000..d47fa8393cbc8 --- /dev/null +++ b/rust/build_error.rs @@ -0,0 +1,33 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Build-time error. +//! +//! This crate provides a function `build_error`, which will panic in +//! compile-time if executed in const context, and will cause a build error +//! if not executed at compile time and the optimizer does not optimise away the +//! call. +//! +//! It is used by `build_assert!` in the kernel crate, allowing checking of +//! conditions that could be checked statically, but could not be enforced in +//! Rust yet (e.g. perform some checks in const functions, but those +//! functions could still be called in the runtime). + +#![no_std] +#![feature(const_panic, core_panic)] + +/// Panics if executed in const context, or triggers a build error if not. +#[inline(never)] +#[cold] +#[no_mangle] +#[track_caller] +pub const fn build_error(msg: &'static str) -> ! { + // Could also be `panic!(msg)` to avoid using unstable feature `core_panic`, + // but it is not allowed in Rust 2021, while `panic!("{}", msg)` could not + // yet be used in const context. + core::panicking::panic(msg); +} + +#[cfg(CONFIG_RUST_BUILD_ASSERT_WARN)] +#[link_section = ".gnu.warning.build_error"] +#[used] +static BUILD_ERROR_WARNING: [u8; 45] = *b"call to build_error present after compilation";