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 7A751C433FE for ; Mon, 23 May 2022 02:04:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352459AbiEWCEF (ORCPT ); Sun, 22 May 2022 22:04:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41650 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352311AbiEWCDv (ORCPT ); Sun, 22 May 2022 22:03:51 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B3DE43982E; Sun, 22 May 2022 19:03:31 -0700 (PDT) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 3A72E60FD7; Mon, 23 May 2022 02:03:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9E455C34113; Mon, 23 May 2022 02:03:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1653271410; bh=vbNh5V+If7BMOjgvnKPpE36qR1+NfFcgaQxIO6y+Mq4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YWzPuA+9psavWwLq35M/pqJIXrSIU2Fgq/Gv4WznPVO2b+fZ07cdFAaBhN/0q4BB3 5TJKTq3eF9zw3bytBpdU1u4jGXXq3y1hjXq3/ppNykMkU1GKw5DmSYdD9zTUJflX5y hhGIbIeVBzCA+CvVRI0bdAHiMX66PHpNZbanitGGKp/BKIqDwtFTy94LfCNTwOZ4vY p5nXM7c85FzEJ6lLryTj5nXbicewYGquvuHGml1LN9+ojemV8jjXu99x4+3g5+45sE yRAzNEULjwggRK/V3CdXLoFOFQp8KoWysT/ZSdplp6SqUJNKR3jY/iXXCn7OJXju5q B7c/JA9qs294g== From: Miguel Ojeda To: Linus Torvalds , Greg Kroah-Hartman Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Jarkko Sakkinen , Miguel Ojeda , Gary Guo , Alex Gaynor , Wedson Almeida Filho Subject: [PATCH v7 09/25] rust: add `build_error` crate Date: Mon, 23 May 2022 04:01:22 +0200 Message-Id: <20220523020209.11810-10-ojeda@kernel.org> In-Reply-To: <20220523020209.11810-1-ojeda@kernel.org> References: <20220523020209.11810-1-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"; -- 2.36.1