diff options
Diffstat (limited to 'library/core/src/ub_checks.rs')
| -rw-r--r-- | library/core/src/ub_checks.rs | 35 |
1 files changed, 31 insertions, 4 deletions
diff --git a/library/core/src/ub_checks.rs b/library/core/src/ub_checks.rs index 2c5b4699806..ff6b2d30539 100644 --- a/library/core/src/ub_checks.rs +++ b/library/core/src/ub_checks.rs @@ -1,7 +1,7 @@ //! Provides the [`assert_unsafe_precondition`] macro as well as some utility functions that cover //! common preconditions. -use crate::intrinsics::const_eval_select; +use crate::intrinsics::{self, const_eval_select}; /// Check that the preconditions of an unsafe function are followed. The check is enabled at /// runtime if debug assertions are enabled when the caller is monomorphized. In const-eval/Miri @@ -45,7 +45,7 @@ use crate::intrinsics::const_eval_select; /// order to call it. Since the precompiled standard library is built with full debuginfo and these /// variables cannot be optimized out in MIR, an innocent-looking `let` can produce enough /// debuginfo to have a measurable compile-time impact on debug builds. -#[allow_internal_unstable(ub_checks)] // permit this to be called in stably-const fn +#[allow_internal_unstable(const_ub_checks)] // permit this to be called in stably-const fn macro_rules! assert_unsafe_precondition { ($kind:ident, $message:expr, ($($name:ident:$ty:ty = $arg:expr),*$(,)?) => $e:expr $(,)?) => { { @@ -60,7 +60,7 @@ macro_rules! assert_unsafe_precondition { #[rustc_no_mir_inline] #[inline] #[rustc_nounwind] - #[rustc_const_unstable(feature = "ub_checks", issue = "none")] + #[rustc_const_unstable(feature = "const_ub_checks", issue = "none")] const fn precondition_check($($name:$ty),*) { if !$e { ::core::panicking::panic_nounwind( @@ -69,7 +69,7 @@ macro_rules! assert_unsafe_precondition { } } - if ::core::intrinsics::$kind() { + if ::core::ub_checks::$kind() { precondition_check($($arg,)*); } } @@ -77,6 +77,33 @@ macro_rules! assert_unsafe_precondition { } pub(crate) use assert_unsafe_precondition; +/// Checking library UB is always enabled when UB-checking is done +/// (and we use a reexport so that there is no unnecessary wrapper function). +pub(crate) use intrinsics::ub_checks as check_library_ub; + +/// Determines whether we should check for language UB. +/// +/// The intention is to not do that when running in the interpreter, as that one has its own +/// language UB checks which generally produce better errors. +#[rustc_const_unstable(feature = "const_ub_checks", issue = "none")] +#[inline] +pub(crate) const fn check_language_ub() -> bool { + #[inline] + fn runtime() -> bool { + // Disable UB checks in Miri. + !cfg!(miri) + } + + #[inline] + const fn comptime() -> bool { + // Always disable UB checks. + false + } + + // Only used for UB checks so we may const_eval_select. + intrinsics::ub_checks() && const_eval_select((), comptime, runtime) +} + /// Checks whether `ptr` is properly aligned with respect to /// `align_of::<T>()`. /// |