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 8D88EC4332F for ; Mon, 6 Dec 2021 14:05:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245381AbhLFOJV (ORCPT ); Mon, 6 Dec 2021 09:09:21 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:59606 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245289AbhLFOJM (ORCPT ); Mon, 6 Dec 2021 09:09:12 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 05B7A612D3; Mon, 6 Dec 2021 14:05:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3294BC341C7; Mon, 6 Dec 2021 14:05:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1638799542; bh=djVvJq0SeChq//87siY+8qVZP1K+LepHsJVacGCfPbI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ety92jmBBqUrhJ2o1pC64DiHcyHav5gdI5faDs1nd5lx6yfDY3t6HGdMTRxRdd/kD tyHmV8n6LF2QnAOjK446xQwmdIbjckmX1yTFmC11n0PUMKURSHee3qfKWDiE3QoPc7 Mkaz3lgfN7F5WYdi6o7uIq6TSASXjyeyVbxxysx3j0AxfEslnpzk94WtuvRRESGvA4 Y8EhKfLJUim7fL4saa/110xShX/PwFoJtjxyEczCRa9ZjDkO0H3JzPPbx9Kh61L5WS VAvMVoZLyEd2KRZsQnTdypiiNyg8QyFfiaMwstdbCphjwb01ksBKiNk8hEvIEzBlts zyRoP9oJCjBMw== 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, Gary Guo , Alex Gaynor , Wedson Almeida Filho , Miguel Ojeda Subject: [PATCH 07/19] rust: add `build_error` crate Date: Mon, 6 Dec 2021 15:03:01 +0100 Message-Id: <20211206140313.5653-8-ojeda@kernel.org> In-Reply-To: <20211206140313.5653-1-ojeda@kernel.org> References: <20211206140313.5653-1-ojeda@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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"; -- 2.34.0