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From: Miguel Ojeda <ojeda@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: rust-for-linux@vger.kernel.org, linux-kbuild@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	Miguel Ojeda <ojeda@kernel.org>, Gary Guo <gary@garyguo.net>,
	Alex Gaynor <alex.gaynor@gmail.com>,
	Wedson Almeida Filho <wedsonaf@google.com>
Subject: [PATCH v3 07/19] rust: add `build_error` crate
Date: Mon, 17 Jan 2022 06:33:37 +0100	[thread overview]
Message-ID: <20220117053349.6804-8-ojeda@kernel.org> (raw)
In-Reply-To: <20220117053349.6804-1-ojeda@kernel.org>

From: Gary Guo <gary@garyguo.net>

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 <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 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


  parent reply	other threads:[~2022-01-17  5:34 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-17  5:33 [PATCH v3 00/19] Rust support Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 01/19] kallsyms: support "big" kernel symbols Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 02/19] kallsyms: increase maximum kernel symbol length to 512 Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 03/19] kallsyms: use the correct buffer size for symbols Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 04/19] rust: add C helpers Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 05/19] rust: add `compiler_builtins` crate Miguel Ojeda
2022-01-17  5:33 ` Miguel Ojeda [this message]
2022-01-17  5:33 ` [PATCH v3 08/19] rust: add `macros` crate Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 10/19] rust: export generated symbols Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 11/19] vsprintf: add new `%pA` format specifier Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 12/19] scripts: add `generate_rust_analyzer.py` Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 13/19] scripts: decode_stacktrace: demangle Rust symbols Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 14/19] docs: add Rust documentation Miguel Ojeda
2022-01-18 22:33   ` Jonathan Corbet
2022-01-19 13:58     ` Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 15/19] Kbuild: add Rust support Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 16/19] samples: add Rust examples Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 17/19] MAINTAINERS: Rust Miguel Ojeda
2022-01-17  5:33 ` [RFC PATCH v3 18/19] drivers: gpio: PrimeCell PL061 in Rust Miguel Ojeda

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