Rollup of 8 pull requests

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -263,6 +263,12 @@ impl<'tcx> CompileTimeInterpCx<'tcx> {
     }
 
     /// See documentation on the `ptr_guaranteed_cmp` intrinsic.
+    /// Returns `2` if the result is unknown.
+    /// Returns `1` if the pointers are guaranteed equal.
+    /// Returns `0` if the pointers are guaranteed inequal.
+    ///
+    /// Note that this intrinsic is exposed on stable for comparison with null. In other words, any
+    /// change to this function that affects comparison with null is insta-stable!
     fn guaranteed_cmp(&mut self, a: Scalar, b: Scalar) -> InterpResult<'tcx, u8> {
         interp_ok(match (a, b) {
             // Comparisons between integers are always known.

compiler/rustc_monomorphize/src/mono_checks/abi_check.rs

@@ -36,9 +36,7 @@ fn do_check_abi<'tcx>(
     target_feature_def: DefId,
     mut emit_err: impl FnMut(Option<&'static str>),
 ) {
-    let Some(feature_def) = tcx.sess.target.features_for_correct_vector_abi() else {
-        return;
-    };
+    let feature_def = tcx.sess.target.features_for_correct_vector_abi();
     let codegen_attrs = tcx.codegen_fn_attrs(target_feature_def);
     for arg_abi in abi.args.iter().chain(std::iter::once(&abi.ret)) {
         let size = arg_abi.layout.size;

compiler/rustc_target/src/target_features.rs

@@ -598,7 +598,12 @@ const S390X_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] = &[
 const RISCV_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] =
     &[/*(64, "zvl64b"), */ (128, "v")];
 // Always warn on SPARC, as the necessary target features cannot be enabled in Rust at the moment.
-const SPARC_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] = &[/*(128, "vis")*/];
+const SPARC_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] = &[/*(64, "vis")*/];
+
+const HEXAGON_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] =
+    &[/*(512, "hvx-length64b"),*/ (1024, "hvx-length128b")];
+const MIPS_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] = &[(128, "msa")];
+const CSKY_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] = &[(128, "vdspv1")];
 
 impl super::spec::Target {
     pub fn rust_target_features(&self) -> &'static [(&'static str, Stability, ImpliedFeatures)] {
@@ -620,20 +625,24 @@ impl super::spec::Target {
         }
     }
 
-    // Returns None if we do not support ABI checks on the given target yet.
-    pub fn features_for_correct_vector_abi(&self) -> Option<&'static [(u64, &'static str)]> {
+    pub fn features_for_correct_vector_abi(&self) -> &'static [(u64, &'static str)] {
         match &*self.arch {
-            "x86" | "x86_64" => Some(X86_FEATURES_FOR_CORRECT_VECTOR_ABI),
-            "aarch64" | "arm64ec" => Some(AARCH64_FEATURES_FOR_CORRECT_VECTOR_ABI),
-            "arm" => Some(ARM_FEATURES_FOR_CORRECT_VECTOR_ABI),
-            "powerpc" | "powerpc64" => Some(POWERPC_FEATURES_FOR_CORRECT_VECTOR_ABI),
-            "loongarch64" => Some(&[]), // on-stack ABI, so we complain about all by-val vectors
-            "riscv32" | "riscv64" => Some(RISCV_FEATURES_FOR_CORRECT_VECTOR_ABI),
-            "wasm32" | "wasm64" => Some(WASM_FEATURES_FOR_CORRECT_VECTOR_ABI),
-            "s390x" => Some(S390X_FEATURES_FOR_CORRECT_VECTOR_ABI),
-            "sparc" | "sparc64" => Some(SPARC_FEATURES_FOR_CORRECT_VECTOR_ABI),
-            // FIXME: add support for non-tier2 architectures
-            _ => None,
+            "x86" | "x86_64" => X86_FEATURES_FOR_CORRECT_VECTOR_ABI,
+            "aarch64" | "arm64ec" => AARCH64_FEATURES_FOR_CORRECT_VECTOR_ABI,
+            "arm" => ARM_FEATURES_FOR_CORRECT_VECTOR_ABI,
+            "powerpc" | "powerpc64" => POWERPC_FEATURES_FOR_CORRECT_VECTOR_ABI,
+            "loongarch64" => &[], // on-stack ABI, so we complain about all by-val vectors
+            "riscv32" | "riscv64" => RISCV_FEATURES_FOR_CORRECT_VECTOR_ABI,
+            "wasm32" | "wasm64" => WASM_FEATURES_FOR_CORRECT_VECTOR_ABI,
+            "s390x" => S390X_FEATURES_FOR_CORRECT_VECTOR_ABI,
+            "sparc" | "sparc64" => SPARC_FEATURES_FOR_CORRECT_VECTOR_ABI,
+            "hexagon" => HEXAGON_FEATURES_FOR_CORRECT_VECTOR_ABI,
+            "mips" | "mips32r6" | "mips64" | "mips64r6" => MIPS_FEATURES_FOR_CORRECT_VECTOR_ABI,
+            "bpf" => &[], // no vector ABI
+            "csky" => CSKY_FEATURES_FOR_CORRECT_VECTOR_ABI,
+            // FIXME: for some tier3 targets, we are overly cautious and always give warnings
+            // when passing args in vector registers.
+            _ => &[],
         }
     }
 

library/alloc/src/string.rs

@@ -116,7 +116,7 @@ use crate::vec::Vec;
 /// `String`s are always valid UTF-8. If you need a non-UTF-8 string, consider
 /// [`OsString`]. It is similar, but without the UTF-8 constraint. Because UTF-8
 /// is a variable width encoding, `String`s are typically smaller than an array of
-/// the same `chars`:
+/// the same `char`s:
 ///
 /// ```
 /// use std::mem;

library/core/src/intrinsics/mod.rs

@@ -3292,8 +3292,8 @@ pub const unsafe fn ptr_offset_from_unsigned<T>(_ptr: *const T, _base: *const T)
 
 /// See documentation of `<*const T>::guaranteed_eq` for details.
 /// Returns `2` if the result is unknown.
-/// Returns `1` if the pointers are guaranteed equal
-/// Returns `0` if the pointers are guaranteed inequal
+/// Returns `1` if the pointers are guaranteed equal.
+/// Returns `0` if the pointers are guaranteed inequal.
 #[cfg_attr(bootstrap, rustc_const_unstable(feature = "const_raw_ptr_comparison", issue = "53020"))]
 #[rustc_intrinsic]
 #[rustc_nounwind]
@@ -3535,7 +3535,6 @@ pub(crate) macro const_eval_select {
 /// In other words, the following code has *Undefined Behavior*:
 ///
 /// ```no_run
-/// #![feature(is_val_statically_known)]
 /// #![feature(core_intrinsics)]
 /// # #![allow(internal_features)]
 /// use std::hint::unreachable_unchecked;
@@ -3548,7 +3547,6 @@ pub(crate) macro const_eval_select {
 /// may panic, or it may not:
 ///
 /// ```no_run
-/// #![feature(is_val_statically_known)]
 /// #![feature(core_intrinsics)]
 /// # #![allow(internal_features)]
 /// use std::intrinsics::is_val_statically_known;
@@ -3581,7 +3579,6 @@ pub(crate) macro const_eval_select {
 /// behave identically:
 ///
 /// ```
-/// #![feature(is_val_statically_known)]
 /// #![feature(core_intrinsics)]
 /// # #![allow(internal_features)]
 /// use std::intrinsics::is_val_statically_known;
@@ -3598,7 +3595,11 @@ pub(crate) macro const_eval_select {
 /// # _ = foo(&5_i32);
 /// # _ = bar(&5_i32);
 /// ```
-#[rustc_const_unstable(feature = "is_val_statically_known", issue = "none")]
+#[cfg_attr(
+    bootstrap,
+    rustc_const_stable(feature = "const_is_val_statically_known", since = "CURRENT_RUSTC_VERSION")
+)]
+#[cfg_attr(not(bootstrap), rustc_const_stable_indirect)]
 #[rustc_nounwind]
 #[unstable(feature = "core_intrinsics", issue = "none")]
 #[rustc_intrinsic]
@@ -4013,9 +4014,9 @@ pub const unsafe fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: us
             count: usize = count,
         ) => {
             let zero_size = count == 0 || size == 0;
-            ub_checks::is_aligned_and_not_null(src, align, zero_size)
-                && ub_checks::is_aligned_and_not_null(dst, align, zero_size)
-                && ub_checks::is_nonoverlapping(src, dst, size, count)
+            ub_checks::maybe_is_aligned_and_not_null(src, align, zero_size)
+                && ub_checks::maybe_is_aligned_and_not_null(dst, align, zero_size)
+                && ub_checks::maybe_is_nonoverlapping(src, dst, size, count)
         }
     );
 
@@ -4119,8 +4120,8 @@ pub const unsafe fn copy<T>(src: *const T, dst: *mut T, count: usize) {
                 align: usize = align_of::<T>(),
                 zero_size: bool = T::IS_ZST || count == 0,
             ) =>
-            ub_checks::is_aligned_and_not_null(src, align, zero_size)
-                && ub_checks::is_aligned_and_not_null(dst, align, zero_size)
+            ub_checks::maybe_is_aligned_and_not_null(src, align, zero_size)
+                && ub_checks::maybe_is_aligned_and_not_null(dst, align, zero_size)
         );
         copy(src, dst, count)
     }
@@ -4201,7 +4202,7 @@ pub const unsafe fn write_bytes<T>(dst: *mut T, val: u8, count: usize) {
                 addr: *const () = dst as *const (),
                 align: usize = align_of::<T>(),
                 zero_size: bool = T::IS_ZST || count == 0,
-            ) => ub_checks::is_aligned_and_not_null(addr, align, zero_size)
+            ) => ub_checks::maybe_is_aligned_and_not_null(addr, align, zero_size)
         );
         write_bytes(dst, val, count)
     }

library/core/src/lib.rs

@@ -109,6 +109,7 @@
 // tidy-alphabetical-start
 #![cfg_attr(bootstrap, feature(const_exact_div))]
 #![cfg_attr(bootstrap, feature(const_fmt_arguments_new))]
+#![cfg_attr(bootstrap, feature(const_ub_checks))]
 #![feature(array_ptr_get)]
 #![feature(asm_experimental_arch)]
 #![feature(const_align_of_val)]
@@ -121,7 +122,6 @@
 #![feature(const_heap)]
 #![feature(const_nonnull_new)]
 #![feature(const_pin_2)]
-#![feature(const_ptr_is_null)]
 #![feature(const_ptr_sub_ptr)]
 #![feature(const_raw_ptr_comparison)]
 #![feature(const_size_of_val)]
@@ -132,14 +132,12 @@
 #![feature(const_type_id)]
 #![feature(const_type_name)]
 #![feature(const_typed_swap)]
-#![feature(const_ub_checks)]
 #![feature(core_intrinsics)]
 #![feature(coverage_attribute)]
 #![feature(do_not_recommend)]
 #![feature(internal_impls_macro)]
 #![feature(ip)]
 #![feature(is_ascii_octdigit)]
-#![feature(is_val_statically_known)]
 #![feature(lazy_get)]
 #![feature(link_cfg)]
 #![feature(non_null_from_ref)]

library/core/src/num/int_macros.rs

@@ -2242,7 +2242,6 @@ macro_rules! int_impl {
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
-        #[rustc_allow_const_fn_unstable(is_val_statically_known)]
         pub const fn wrapping_pow(self, mut exp: u32) -> Self {
             if exp == 0 {
                 return 1;
@@ -2808,7 +2807,6 @@ macro_rules! int_impl {
                       without modifying the original"]
         #[inline]
         #[rustc_inherit_overflow_checks]
-        #[rustc_allow_const_fn_unstable(is_val_statically_known)]
         pub const fn pow(self, mut exp: u32) -> Self {
             if exp == 0 {
                 return 1;

library/core/src/num/uint_macros.rs

@@ -2251,7 +2251,6 @@ macro_rules! uint_impl {
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         #[inline]
-        #[rustc_allow_const_fn_unstable(is_val_statically_known)]
         pub const fn wrapping_pow(self, mut exp: u32) -> Self {
             if exp == 0 {
                 return 1;
@@ -2791,7 +2790,6 @@ macro_rules! uint_impl {
                       without modifying the original"]
         #[inline]
         #[rustc_inherit_overflow_checks]
-        #[rustc_allow_const_fn_unstable(is_val_statically_known)]
         pub const fn pow(self, mut exp: u32) -> Self {
             if exp == 0 {
                 return 1;

library/core/src/ptr/const_ptr.rs

@@ -29,16 +29,18 @@ impl<T: ?Sized> *const T {
     /// assert!(!ptr.is_null());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_const_unstable(feature = "const_ptr_is_null", issue = "74939")]
+    #[rustc_const_stable(feature = "const_ptr_is_null", since = "CURRENT_RUSTC_VERSION")]
     #[rustc_diagnostic_item = "ptr_const_is_null"]
     #[inline]
+    #[rustc_allow_const_fn_unstable(const_eval_select)]
     pub const fn is_null(self) -> bool {
         // Compare via a cast to a thin pointer, so fat pointers are only
         // considering their "data" part for null-ness.
         let ptr = self as *const u8;
         const_eval_select!(
             @capture { ptr: *const u8 } -> bool:
-            if const #[rustc_const_unstable(feature = "const_ptr_is_null", issue = "74939")] {
+            // This use of `const_raw_ptr_comparison` has been explicitly blessed by t-lang.
+            if const #[rustc_allow_const_fn_unstable(const_raw_ptr_comparison)] {
                 match (ptr).guaranteed_eq(null_mut()) {
                     Some(res) => res,
                     // To remain maximally convervative, we stop execution when we don't
@@ -280,7 +282,7 @@ impl<T: ?Sized> *const T {
     /// }
     /// ```
     #[stable(feature = "ptr_as_ref", since = "1.9.0")]
-    #[rustc_const_unstable(feature = "const_ptr_is_null", issue = "74939")]
+    #[rustc_const_stable(feature = "const_ptr_is_null", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
     pub const unsafe fn as_ref<'a>(self) -> Option<&'a T> {
         // SAFETY: the caller must guarantee that `self` is valid

library/core/src/ptr/mod.rs

@@ -1103,9 +1103,9 @@ pub const unsafe fn swap_nonoverlapping<T>(x: *mut T, y: *mut T, count: usize) {
             count: usize = count,
         ) => {
             let zero_size = size == 0 || count == 0;
-            ub_checks::is_aligned_and_not_null(x, align, zero_size)
-                && ub_checks::is_aligned_and_not_null(y, align, zero_size)
-                && ub_checks::is_nonoverlapping(x, y, size, count)
+            ub_checks::maybe_is_aligned_and_not_null(x, align, zero_size)
+                && ub_checks::maybe_is_aligned_and_not_null(y, align, zero_size)
+                && ub_checks::maybe_is_nonoverlapping(x, y, size, count)
         }
     );
 
@@ -1216,7 +1216,7 @@ pub const unsafe fn replace<T>(dst: *mut T, src: T) -> T {
                 addr: *const () = dst as *const (),
                 align: usize = align_of::<T>(),
                 is_zst: bool = T::IS_ZST,
-            ) => ub_checks::is_aligned_and_not_null(addr, align, is_zst)
+            ) => ub_checks::maybe_is_aligned_and_not_null(addr, align, is_zst)
         );
         mem::replace(&mut *dst, src)
     }
@@ -1369,7 +1369,7 @@ pub const unsafe fn read<T>(src: *const T) -> T {
                 addr: *const () = src as *const (),
                 align: usize = align_of::<T>(),
                 is_zst: bool = T::IS_ZST,
-            ) => ub_checks::is_aligned_and_not_null(addr, align, is_zst)
+            ) => ub_checks::maybe_is_aligned_and_not_null(addr, align, is_zst)
         );
         crate::intrinsics::read_via_copy(src)
     }
@@ -1573,7 +1573,7 @@ pub const unsafe fn write<T>(dst: *mut T, src: T) {
                 addr: *mut () = dst as *mut (),
                 align: usize = align_of::<T>(),
                 is_zst: bool = T::IS_ZST,
-            ) => ub_checks::is_aligned_and_not_null(addr, align, is_zst)
+            ) => ub_checks::maybe_is_aligned_and_not_null(addr, align, is_zst)
         );
         intrinsics::write_via_move(dst, src)
     }
@@ -1745,7 +1745,7 @@ pub unsafe fn read_volatile<T>(src: *const T) -> T {
                 addr: *const () = src as *const (),
                 align: usize = align_of::<T>(),
                 is_zst: bool = T::IS_ZST,
-            ) => ub_checks::is_aligned_and_not_null(addr, align, is_zst)
+            ) => ub_checks::maybe_is_aligned_and_not_null(addr, align, is_zst)
         );
         intrinsics::volatile_load(src)
     }
@@ -1825,7 +1825,7 @@ pub unsafe fn write_volatile<T>(dst: *mut T, src: T) {
                 addr: *mut () = dst as *mut (),
                 align: usize = align_of::<T>(),
                 is_zst: bool = T::IS_ZST,
-            ) => ub_checks::is_aligned_and_not_null(addr, align, is_zst)
+            ) => ub_checks::maybe_is_aligned_and_not_null(addr, align, is_zst)
         );
         intrinsics::volatile_store(dst, src);
     }

library/core/src/ptr/mut_ptr.rs

@@ -29,7 +29,7 @@ impl<T: ?Sized> *mut T {
     /// assert!(!ptr.is_null());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_const_unstable(feature = "const_ptr_is_null", issue = "74939")]
+    #[rustc_const_stable(feature = "const_ptr_is_null", since = "CURRENT_RUSTC_VERSION")]
     #[rustc_diagnostic_item = "ptr_is_null"]
     #[inline]
     pub const fn is_null(self) -> bool {
@@ -271,7 +271,7 @@ impl<T: ?Sized> *mut T {
     /// }
     /// ```
     #[stable(feature = "ptr_as_ref", since = "1.9.0")]
-    #[rustc_const_unstable(feature = "const_ptr_is_null", issue = "74939")]
+    #[rustc_const_stable(feature = "const_ptr_is_null", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
     pub const unsafe fn as_ref<'a>(self) -> Option<&'a T> {
         // SAFETY: the caller must guarantee that `self` is valid for a
@@ -619,7 +619,7 @@ impl<T: ?Sized> *mut T {
     /// println!("{s:?}"); // It'll print: "[4, 2, 3]".
     /// ```
     #[stable(feature = "ptr_as_ref", since = "1.9.0")]
-    #[rustc_const_unstable(feature = "const_ptr_is_null", issue = "74939")]
+    #[rustc_const_stable(feature = "const_ptr_is_null", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
     pub const unsafe fn as_mut<'a>(self) -> Option<&'a mut T> {
         // SAFETY: the caller must guarantee that `self` is be valid for

library/core/src/slice/raw.rs

@@ -132,7 +132,7 @@ pub const unsafe fn from_raw_parts<'a, T>(data: *const T, len: usize) -> &'a [T]
                 align: usize = align_of::<T>(),
                 len: usize = len,
             ) =>
-            ub_checks::is_aligned_and_not_null(data, align, false)
+            ub_checks::maybe_is_aligned_and_not_null(data, align, false)
                 && ub_checks::is_valid_allocation_size(size, len)
         );
         &*ptr::slice_from_raw_parts(data, len)
@@ -186,7 +186,7 @@ pub const unsafe fn from_raw_parts_mut<'a, T>(data: *mut T, len: usize) -> &'a m
                 align: usize = align_of::<T>(),
                 len: usize = len,
             ) =>
-            ub_checks::is_aligned_and_not_null(data, align, false)
+            ub_checks::maybe_is_aligned_and_not_null(data, align, false)
                 && ub_checks::is_valid_allocation_size(size, len)
         );
         &mut *ptr::slice_from_raw_parts_mut(data, len)

library/core/src/sync/atomic.rs

@@ -469,7 +469,7 @@ impl AtomicBool {
     /// [valid]: crate::ptr#safety
     /// [Memory model for atomic accesses]: self#memory-model-for-atomic-accesses
     #[stable(feature = "atomic_from_ptr", since = "1.75.0")]
-    #[rustc_const_unstable(feature = "const_atomic_from_ptr", issue = "108652")]
+    #[rustc_const_stable(feature = "const_atomic_from_ptr", since = "CURRENT_RUSTC_VERSION")]
     pub const unsafe fn from_ptr<'a>(ptr: *mut bool) -> &'a AtomicBool {
         // SAFETY: guaranteed by the caller
         unsafe { &*ptr.cast() }
@@ -1264,7 +1264,7 @@ impl<T> AtomicPtr<T> {
     /// [valid]: crate::ptr#safety
     /// [Memory model for atomic accesses]: self#memory-model-for-atomic-accesses
     #[stable(feature = "atomic_from_ptr", since = "1.75.0")]
-    #[rustc_const_unstable(feature = "const_atomic_from_ptr", issue = "108652")]
+    #[rustc_const_stable(feature = "const_atomic_from_ptr", since = "CURRENT_RUSTC_VERSION")]
     pub const unsafe fn from_ptr<'a>(ptr: *mut *mut T) -> &'a AtomicPtr<T> {
         // SAFETY: guaranteed by the caller
         unsafe { &*ptr.cast() }
@@ -2263,7 +2263,7 @@ macro_rules! atomic_int {
             /// [valid]: crate::ptr#safety
             /// [Memory model for atomic accesses]: self#memory-model-for-atomic-accesses
             #[stable(feature = "atomic_from_ptr", since = "1.75.0")]
-            #[rustc_const_unstable(feature = "const_atomic_from_ptr", issue = "108652")]
+            #[rustc_const_stable(feature = "const_atomic_from_ptr", since = "CURRENT_RUSTC_VERSION")]
             pub const unsafe fn from_ptr<'a>(ptr: *mut $int_type) -> &'a $atomic_type {
                 // SAFETY: guaranteed by the caller
                 unsafe { &*ptr.cast() }