1*ecaa6ddfSGary Guo // SPDX-License-Identifier: GPL-2.0 2*ecaa6ddfSGary Guo 3*ecaa6ddfSGary Guo //! Build-time error. 4*ecaa6ddfSGary Guo //! 5*ecaa6ddfSGary Guo //! This crate provides a [const function][const-functions] `build_error`, which will panic in 6*ecaa6ddfSGary Guo //! compile-time if executed in [const context][const-context], and will cause a build error 7*ecaa6ddfSGary Guo //! if not executed at compile time and the optimizer does not optimise away the call. 8*ecaa6ddfSGary Guo //! 9*ecaa6ddfSGary Guo //! It is used by `build_assert!` in the kernel crate, allowing checking of 10*ecaa6ddfSGary Guo //! conditions that could be checked statically, but could not be enforced in 11*ecaa6ddfSGary Guo //! Rust yet (e.g. perform some checks in [const functions][const-functions], but those 12*ecaa6ddfSGary Guo //! functions could still be called in the runtime). 13*ecaa6ddfSGary Guo //! 14*ecaa6ddfSGary Guo //! For details on constant evaluation in Rust, please see the [Reference][const-eval]. 15*ecaa6ddfSGary Guo //! 16*ecaa6ddfSGary Guo //! [const-eval]: https://doc.rust-lang.org/reference/const_eval.html 17*ecaa6ddfSGary Guo //! [const-functions]: https://doc.rust-lang.org/reference/const_eval.html#const-functions 18*ecaa6ddfSGary Guo //! [const-context]: https://doc.rust-lang.org/reference/const_eval.html#const-context 19*ecaa6ddfSGary Guo 20*ecaa6ddfSGary Guo #![no_std] 21*ecaa6ddfSGary Guo 22*ecaa6ddfSGary Guo /// Panics if executed in [const context][const-context], or triggers a build error if not. 23*ecaa6ddfSGary Guo /// 24*ecaa6ddfSGary Guo /// [const-context]: https://doc.rust-lang.org/reference/const_eval.html#const-context 25*ecaa6ddfSGary Guo #[inline(never)] 26*ecaa6ddfSGary Guo #[cold] 27*ecaa6ddfSGary Guo #[export_name = "rust_build_error"] 28*ecaa6ddfSGary Guo #[track_caller] build_error(msg: &'static str) -> !29*ecaa6ddfSGary Guopub const fn build_error(msg: &'static str) -> ! { 30*ecaa6ddfSGary Guo panic!("{}", msg); 31*ecaa6ddfSGary Guo } 32