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author | Kalle Valo <kvalo@kernel.org> | 2023-01-17 13:36:25 +0200 |
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committer | Kalle Valo <kvalo@kernel.org> | 2023-01-17 13:36:25 +0200 |
commit | d0e99511834b6828c960e978d9a8cb6e5731250d (patch) | |
tree | e7b062c1f9d28a55083477a1462286a7923a57fd /rust/kernel/build_assert.rs | |
parent | de7d0ff301fccc75281d7d8eb98c4a47faacf32d (diff) | |
parent | 80f8a66dede0a4b4e9e846765a97809c6fe49ce5 (diff) | |
download | linux-d0e99511834b6828c960e978d9a8cb6e5731250d.tar.gz linux-d0e99511834b6828c960e978d9a8cb6e5731250d.tar.bz2 linux-d0e99511834b6828c960e978d9a8cb6e5731250d.zip |
Merge wireless into wireless-next
Due to the two cherry picked commits from wireless to wireless-next we have
several conflicts in mt76. To avoid any bugs with conflicts merge wireless into
wireless-next.
96f134dc1964 wifi: mt76: handle possible mt76_rx_token_consume failures
fe13dad8992b wifi: mt76: dma: do not increment queue head if mt76_dma_add_buf fails
Diffstat (limited to 'rust/kernel/build_assert.rs')
-rw-r--r-- | rust/kernel/build_assert.rs | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/rust/kernel/build_assert.rs b/rust/kernel/build_assert.rs new file mode 100644 index 000000000000..659542393c09 --- /dev/null +++ b/rust/kernel/build_assert.rs @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Build-time assert. + +/// Fails the build if the code path calling `build_error!` can possibly be executed. +/// +/// If the macro is executed in const context, `build_error!` will panic. +/// If the compiler or optimizer cannot guarantee that `build_error!` can never +/// be called, a build error will be triggered. +/// +/// # Examples +/// +/// ``` +/// # use kernel::build_error; +/// #[inline] +/// fn foo(a: usize) -> usize { +/// a.checked_add(1).unwrap_or_else(|| build_error!("overflow")) +/// } +/// +/// assert_eq!(foo(usize::MAX - 1), usize::MAX); // OK. +/// // foo(usize::MAX); // Fails to compile. +/// ``` +#[macro_export] +macro_rules! build_error { + () => {{ + $crate::build_error("") + }}; + ($msg:expr) => {{ + $crate::build_error($msg) + }}; +} + +/// Asserts that a boolean expression is `true` at compile time. +/// +/// If the condition is evaluated to `false` in const context, `build_assert!` +/// will panic. If the compiler or optimizer cannot guarantee the condition will +/// be evaluated to `true`, a build error will be triggered. +/// +/// [`static_assert!`] should be preferred to `build_assert!` whenever possible. +/// +/// # Examples +/// +/// These examples show that different types of [`assert!`] will trigger errors +/// at different stage of compilation. It is preferred to err as early as +/// possible, so [`static_assert!`] should be used whenever possible. +/// ```ignore +/// fn foo() { +/// static_assert!(1 > 1); // Compile-time error +/// build_assert!(1 > 1); // Build-time error +/// assert!(1 > 1); // Run-time error +/// } +/// ``` +/// +/// When the condition refers to generic parameters or parameters of an inline function, +/// [`static_assert!`] cannot be used. Use `build_assert!` in this scenario. +/// ``` +/// fn foo<const N: usize>() { +/// // `static_assert!(N > 1);` is not allowed +/// build_assert!(N > 1); // Build-time check +/// assert!(N > 1); // Run-time check +/// } +/// +/// #[inline] +/// fn bar(n: usize) { +/// // `static_assert!(n > 1);` is not allowed +/// build_assert!(n > 1); // Build-time check +/// assert!(n > 1); // Run-time check +/// } +/// ``` +#[macro_export] +macro_rules! build_assert { + ($cond:expr $(,)?) => {{ + if !$cond { + $crate::build_error(concat!("assertion failed: ", stringify!($cond))); + } + }}; + ($cond:expr, $msg:expr) => {{ + if !$cond { + $crate::build_error($msg); + } + }}; +} |