From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 655C7C4321E for ; Mon, 17 Jan 2022 05:34:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232269AbiAQFef (ORCPT ); Mon, 17 Jan 2022 00:34:35 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:47192 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232142AbiAQFe3 (ORCPT ); Mon, 17 Jan 2022 00:34:29 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 68E30B80DCF; Mon, 17 Jan 2022 05:34:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 26EE9C36AEF; Mon, 17 Jan 2022 05:34:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1642397666; bh=q4T/HWnrX6MkEzrYkY7huTX+IcB2Gc3XmNqnnQXC/gg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Om3bJIbmdNRZs8qjTT5TswBGLL5mkxGSGm0fAQSiR5aec7qi9q7IcpHkoJzU9yte+ +IuCyUCTduDfCTpB4hy3Tb7it42V+vUHwapvNZ8aWMR4W0iYULH7P7IgbF/0EzNVhx OsYz14KHAtOKKT/MeUymGMRc52jU9Tc4XOMRubm8c++7Z+10RfO21IZvGCxJvlpl8W luhs47wLhCLCf5RcBBxty+fRDwHmWb8tF5mLEGoXx5L9XI3TiGMh5DYEaMhVr46U4M 6hSqZPD0hA1VUe5l/5OxQ6k0+x85+ECq8EOYYxMqP1uafRbtc1F8TYI/tnlDNBHC61 74vbbURyPs2hg== From: Miguel Ojeda To: Linus Torvalds , Greg Kroah-Hartman Cc: rust-for-linux@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Miguel Ojeda , Gary Guo , Alex Gaynor , Wedson Almeida Filho Subject: [PATCH v3 07/19] rust: add `build_error` crate Date: Mon, 17 Jan 2022 06:33:37 +0100 Message-Id: <20220117053349.6804-8-ojeda@kernel.org> In-Reply-To: <20220117053349.6804-1-ojeda@kernel.org> References: <20220117053349.6804-1-ojeda@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: rust-for-linux@vger.kernel.org From: Gary Guo 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: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Signed-off-by: Gary Guo Co-developed-by: Miguel Ojeda Signed-off-by: Miguel Ojeda --- rust/build_error.rs | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 rust/build_error.rs diff --git a/rust/build_error.rs b/rust/build_error.rs new file mode 100644 index 000000000000..34e589149d3e --- /dev/null +++ b/rust/build_error.rs @@ -0,0 +1,29 @@ +// 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] + +/// 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) -> ! { + 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"; -- 2.34.1