diff options
Diffstat (limited to '')
| -rw-r--r-- | library/core/src/intrinsics.rs | 69 |
1 files changed, 4 insertions, 65 deletions
diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs index 7ed7d767f..a315a28fb 100644 --- a/library/core/src/intrinsics.rs +++ b/library/core/src/intrinsics.rs @@ -55,7 +55,6 @@ #![allow(missing_docs)] use crate::marker::DiscriminantKind; -#[cfg(not(bootstrap))] use crate::marker::Tuple; use crate::mem; @@ -959,13 +958,13 @@ extern "rust-intrinsic" { #[rustc_safe_intrinsic] pub fn assert_zero_valid<T>(); - /// A guard for unsafe functions that cannot ever be executed if `T` has invalid - /// bit patterns: This will statically either panic, or do nothing. + /// A guard for `std::mem::uninitialized`. This will statically either panic, or do nothing. /// /// This intrinsic does not have a stable counterpart. #[rustc_const_unstable(feature = "const_assert_type2", issue = "none")] #[rustc_safe_intrinsic] - pub fn assert_uninit_valid<T>(); + #[cfg(not(bootstrap))] + pub fn assert_mem_uninitialized_valid<T>(); /// Gets a reference to a static `Location` indicating where it was called. /// @@ -2175,66 +2174,6 @@ extern "rust-intrinsic" { /// `unreachable_unchecked` is actually being reached. The bug is in *crate A*, /// which violates the principle that a `const fn` must behave the same at /// compile-time and at run-time. The unsafe code in crate B is fine. - #[cfg(bootstrap)] - #[rustc_const_unstable(feature = "const_eval_select", issue = "none")] - pub fn const_eval_select<ARG, F, G, RET>(arg: ARG, called_in_const: F, called_at_rt: G) -> RET - where - G: FnOnce<ARG, Output = RET>, - F: FnOnce<ARG, Output = RET>; - - /// Selects which function to call depending on the context. - /// - /// If this function is evaluated at compile-time, then a call to this - /// intrinsic will be replaced with a call to `called_in_const`. It gets - /// replaced with a call to `called_at_rt` otherwise. - /// - /// # Type Requirements - /// - /// The two functions must be both function items. They cannot be function - /// pointers or closures. The first function must be a `const fn`. - /// - /// `arg` will be the tupled arguments that will be passed to either one of - /// the two functions, therefore, both functions must accept the same type of - /// arguments. Both functions must return RET. - /// - /// # Safety - /// - /// The two functions must behave observably equivalent. Safe code in other - /// crates may assume that calling a `const fn` at compile-time and at run-time - /// produces the same result. A function that produces a different result when - /// evaluated at run-time, or has any other observable side-effects, is - /// *unsound*. - /// - /// Here is an example of how this could cause a problem: - /// ```no_run - /// #![feature(const_eval_select)] - /// #![feature(core_intrinsics)] - /// use std::hint::unreachable_unchecked; - /// use std::intrinsics::const_eval_select; - /// - /// // Crate A - /// pub const fn inconsistent() -> i32 { - /// fn runtime() -> i32 { 1 } - /// const fn compiletime() -> i32 { 2 } - /// - /// unsafe { - // // ⚠ This code violates the required equivalence of `compiletime` - /// // and `runtime`. - /// const_eval_select((), compiletime, runtime) - /// } - /// } - /// - /// // Crate B - /// const X: i32 = inconsistent(); - /// let x = inconsistent(); - /// if x != X { unsafe { unreachable_unchecked(); }} - /// ``` - /// - /// This code causes Undefined Behavior when being run, since the - /// `unreachable_unchecked` is actually being reached. The bug is in *crate A*, - /// which violates the principle that a `const fn` must behave the same at - /// compile-time and at run-time. The unsafe code in crate B is fine. - #[cfg(not(bootstrap))] #[rustc_const_unstable(feature = "const_eval_select", issue = "none")] pub fn const_eval_select<ARG: Tuple, F, G, RET>( arg: ARG, @@ -2281,7 +2220,7 @@ macro_rules! assert_unsafe_precondition { fn runtime$(<$($tt)*>)?($($i:$ty),*) { if !$e { // don't unwind to reduce impact on code size - ::core::panicking::panic_str_nounwind( + ::core::panicking::panic_nounwind( concat!("unsafe precondition(s) violated: ", $name) ); } |