From 3d3b51570748a1c8c658b44d8184a6dc3a8dbae2 Mon Sep 17 00:00:00 2001 From: Luca Versari Date: Wed, 13 Nov 2024 10:56:51 +0100 Subject: [PATCH 1/6] ABI checks: add support for some tier3 arches, warn on others. --- .../src/mono_checks/abi_check.rs | 4 +- compiler/rustc_target/src/target_features.rs | 37 ++++++++++++------- 2 files changed, 24 insertions(+), 17 deletions(-) diff --git a/compiler/rustc_monomorphize/src/mono_checks/abi_check.rs b/compiler/rustc_monomorphize/src/mono_checks/abi_check.rs index d53595929e733..02b361456e484 100644 --- a/compiler/rustc_monomorphize/src/mono_checks/abi_check.rs +++ b/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; diff --git a/compiler/rustc_target/src/target_features.rs b/compiler/rustc_target/src/target_features.rs index 88536926b1122..112eb8626635a 100644 --- a/compiler/rustc_target/src/target_features.rs +++ b/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. + _ => &[], } } From 427d9152d2f5899f0a338ac96b3e7b33d10e6f97 Mon Sep 17 00:00:00 2001 From: est31 Date: Sat, 16 Nov 2024 05:01:52 +0100 Subject: [PATCH 2/6] Also check if let chains with multiple lets in these two tests --- .../pattern/usefulness/conflicting_bindings.rs | 2 ++ .../usefulness/conflicting_bindings.stderr | 18 +++++++++++++----- .../move-guard-if-let-chain.rs | 11 +++++++++++ .../move-guard-if-let-chain.stderr | 18 +++++++++++++++++- 4 files changed, 43 insertions(+), 6 deletions(-) diff --git a/tests/ui/pattern/usefulness/conflicting_bindings.rs b/tests/ui/pattern/usefulness/conflicting_bindings.rs index 0b3e7ce9e9a0f..16737e0a8946b 100644 --- a/tests/ui/pattern/usefulness/conflicting_bindings.rs +++ b/tests/ui/pattern/usefulness/conflicting_bindings.rs @@ -10,6 +10,8 @@ fn main() { //~^ ERROR: mutable more than once if let Some(ref mut y @ ref mut z) = x && true {} //~^ ERROR: mutable more than once + if let Some(_) = Some(()) && let Some(ref mut y @ ref mut z) = x && true {} + //~^ ERROR: mutable more than once while let Some(ref mut y @ ref mut z) = x {} //~^ ERROR: mutable more than once while let Some(ref mut y @ ref mut z) = x && true {} diff --git a/tests/ui/pattern/usefulness/conflicting_bindings.stderr b/tests/ui/pattern/usefulness/conflicting_bindings.stderr index 679fc83e7f563..6f6504e6f6442 100644 --- a/tests/ui/pattern/usefulness/conflicting_bindings.stderr +++ b/tests/ui/pattern/usefulness/conflicting_bindings.stderr @@ -31,7 +31,15 @@ LL | if let Some(ref mut y @ ref mut z) = x && true {} | value is mutably borrowed by `y` here error: cannot borrow value as mutable more than once at a time - --> $DIR/conflicting_bindings.rs:13:20 + --> $DIR/conflicting_bindings.rs:13:43 + | +LL | if let Some(_) = Some(()) && let Some(ref mut y @ ref mut z) = x && true {} + | ^^^^^^^^^ --------- value is mutably borrowed by `z` here + | | + | value is mutably borrowed by `y` here + +error: cannot borrow value as mutable more than once at a time + --> $DIR/conflicting_bindings.rs:15:20 | LL | while let Some(ref mut y @ ref mut z) = x {} | ^^^^^^^^^ --------- value is mutably borrowed by `z` here @@ -39,7 +47,7 @@ LL | while let Some(ref mut y @ ref mut z) = x {} | value is mutably borrowed by `y` here error: cannot borrow value as mutable more than once at a time - --> $DIR/conflicting_bindings.rs:15:20 + --> $DIR/conflicting_bindings.rs:17:20 | LL | while let Some(ref mut y @ ref mut z) = x && true {} | ^^^^^^^^^ --------- value is mutably borrowed by `z` here @@ -47,7 +55,7 @@ LL | while let Some(ref mut y @ ref mut z) = x && true {} | value is mutably borrowed by `y` here error: cannot borrow value as mutable more than once at a time - --> $DIR/conflicting_bindings.rs:18:9 + --> $DIR/conflicting_bindings.rs:20:9 | LL | ref mut y @ ref mut z => {} | ^^^^^^^^^ --------- value is mutably borrowed by `z` here @@ -55,12 +63,12 @@ LL | ref mut y @ ref mut z => {} | value is mutably borrowed by `y` here error: cannot borrow value as mutable more than once at a time - --> $DIR/conflicting_bindings.rs:21:24 + --> $DIR/conflicting_bindings.rs:23:24 | LL | () if let Some(ref mut y @ ref mut z) = x => {} | ^^^^^^^^^ --------- value is mutably borrowed by `z` here | | | value is mutably borrowed by `y` here -error: aborting due to 8 previous errors +error: aborting due to 9 previous errors diff --git a/tests/ui/rfcs/rfc-2294-if-let-guard/move-guard-if-let-chain.rs b/tests/ui/rfcs/rfc-2294-if-let-guard/move-guard-if-let-chain.rs index 5c333cd7795c7..47653efffb7b8 100644 --- a/tests/ui/rfcs/rfc-2294-if-let-guard/move-guard-if-let-chain.rs +++ b/tests/ui/rfcs/rfc-2294-if-let-guard/move-guard-if-let-chain.rs @@ -94,4 +94,15 @@ fn use_in_arm_ok(c: bool) { }; } +fn use_in_same_chain(c: bool) { + let x: Box<_> = Box::new(1); + + let v = (1, 2); + + match v { + (1, 2) if let y = x && c && let z = x => false, //~ ERROR use of moved value: `x` + _ => true, + }; +} + fn main() {} diff --git a/tests/ui/rfcs/rfc-2294-if-let-guard/move-guard-if-let-chain.stderr b/tests/ui/rfcs/rfc-2294-if-let-guard/move-guard-if-let-chain.stderr index 087e54244b319..123c5f1943024 100644 --- a/tests/ui/rfcs/rfc-2294-if-let-guard/move-guard-if-let-chain.stderr +++ b/tests/ui/rfcs/rfc-2294-if-let-guard/move-guard-if-let-chain.stderr @@ -60,6 +60,22 @@ help: borrow this binding in the pattern to avoid moving the value LL | (1, 2) if let ref y = x && c => false, | +++ -error: aborting due to 4 previous errors +error[E0382]: use of moved value: `x` + --> $DIR/move-guard-if-let-chain.rs:103:41 + | +LL | let x: Box<_> = Box::new(1); + | - move occurs because `x` has type `Box`, which does not implement the `Copy` trait +... +LL | (1, 2) if let y = x && c && let z = x => false, + | - ^ value used here after move + | | + | value moved here + | +help: borrow this binding in the pattern to avoid moving the value + | +LL | (1, 2) if let ref y = x && c && let z = x => false, + | +++ + +error: aborting due to 5 previous errors For more information about this error, try `rustc --explain E0382`. From f502dcea3839ff48a9960e07130f203bfd4a07b2 Mon Sep 17 00:00:00 2001 From: est31 Date: Sat, 16 Nov 2024 05:21:09 +0100 Subject: [PATCH 3/6] Add regression test for issue #103476, fixed in edition 2024 --- .../temporary-early-drop.rs | 25 +++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 tests/ui/rfcs/rfc-2497-if-let-chains/temporary-early-drop.rs diff --git a/tests/ui/rfcs/rfc-2497-if-let-chains/temporary-early-drop.rs b/tests/ui/rfcs/rfc-2497-if-let-chains/temporary-early-drop.rs new file mode 100644 index 0000000000000..389c76337f097 --- /dev/null +++ b/tests/ui/rfcs/rfc-2497-if-let-chains/temporary-early-drop.rs @@ -0,0 +1,25 @@ +// issue-103476 +//@ compile-flags: -Zlint-mir -Zunstable-options +//@ edition: 2024 +//@ check-pass + +#![feature(let_chains)] +#![allow(irrefutable_let_patterns)] + +struct Pd; + +impl Pd { + fn it(&self) -> It { + todo!() + } +} + +pub struct It<'a>(Box>); + +trait Tr<'a> {} + +fn f(m: Option) { + if let Some(n) = m && let it = n.it() {}; +} + +fn main() {} From 5eef5ee38abbccac368871bef0555fc24b2c53f3 Mon Sep 17 00:00:00 2001 From: Ralf Jung Date: Sat, 16 Nov 2024 18:32:25 +0100 Subject: [PATCH 4/6] stabilize const_ptr_is_null --- compiler/rustc_const_eval/src/const_eval/machine.rs | 6 ++++++ library/core/src/intrinsics/mod.rs | 4 ++-- library/core/src/lib.rs | 1 - library/core/src/ptr/const_ptr.rs | 8 +++++--- library/core/src/ptr/mut_ptr.rs | 6 +++--- library/core/src/ub_checks.rs | 2 +- tests/ui/consts/const-ptr-is-null.rs | 1 - tests/ui/consts/const-ptr-is-null.stderr | 2 +- tests/ui/consts/ptr_is_null.rs | 1 - 9 files changed, 18 insertions(+), 13 deletions(-) diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs index 62115aef4a70d..f12320cb85171 100644 --- a/compiler/rustc_const_eval/src/const_eval/machine.rs +++ b/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. diff --git a/library/core/src/intrinsics/mod.rs b/library/core/src/intrinsics/mod.rs index 72e34e5faf5a7..268af1c2965c5 100644 --- a/library/core/src/intrinsics/mod.rs +++ b/library/core/src/intrinsics/mod.rs @@ -3292,8 +3292,8 @@ pub const unsafe fn ptr_offset_from_unsigned(_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] diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs index 6f7ea7694207a..1cacd1d2160aa 100644 --- a/library/core/src/lib.rs +++ b/library/core/src/lib.rs @@ -121,7 +121,6 @@ #![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)] diff --git a/library/core/src/ptr/const_ptr.rs b/library/core/src/ptr/const_ptr.rs index 2d7507e2d53ee..0dbe819acb1b9 100644 --- a/library/core/src/ptr/const_ptr.rs +++ b/library/core/src/ptr/const_ptr.rs @@ -29,16 +29,18 @@ impl *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 *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 diff --git a/library/core/src/ptr/mut_ptr.rs b/library/core/src/ptr/mut_ptr.rs index 344ba46a50e20..f0204bd0f773d 100644 --- a/library/core/src/ptr/mut_ptr.rs +++ b/library/core/src/ptr/mut_ptr.rs @@ -29,7 +29,7 @@ impl *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 *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 *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 diff --git a/library/core/src/ub_checks.rs b/library/core/src/ub_checks.rs index 8fcbda141dab7..e21cd3fcec6ce 100644 --- a/library/core/src/ub_checks.rs +++ b/library/core/src/ub_checks.rs @@ -65,7 +65,7 @@ macro_rules! assert_unsafe_precondition { #[inline] #[rustc_nounwind] #[cfg_attr(bootstrap, rustc_const_unstable(feature = "const_ub_checks", issue = "none"))] - #[rustc_allow_const_fn_unstable(const_ptr_is_null, const_ub_checks)] // only for UB checks + #[rustc_allow_const_fn_unstable(const_ub_checks)] // only for UB checks const fn precondition_check($($name:$ty),*) { if !$e { ::core::panicking::panic_nounwind( diff --git a/tests/ui/consts/const-ptr-is-null.rs b/tests/ui/consts/const-ptr-is-null.rs index 82c293c0ad6e3..92cf87a9782f2 100644 --- a/tests/ui/consts/const-ptr-is-null.rs +++ b/tests/ui/consts/const-ptr-is-null.rs @@ -1,4 +1,3 @@ -#![feature(const_ptr_is_null)] use std::ptr; const IS_NULL: () = { diff --git a/tests/ui/consts/const-ptr-is-null.stderr b/tests/ui/consts/const-ptr-is-null.stderr index 5fd3514281832..f71b37527726f 100644 --- a/tests/ui/consts/const-ptr-is-null.stderr +++ b/tests/ui/consts/const-ptr-is-null.stderr @@ -8,7 +8,7 @@ note: inside `std::ptr::const_ptr::::is_null::compiletime` note: inside `std::ptr::const_ptr::::is_null` --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL note: inside `MAYBE_NULL` - --> $DIR/const-ptr-is-null.rs:17:14 + --> $DIR/const-ptr-is-null.rs:16:14 | LL | assert!(!ptr.wrapping_sub(512).is_null()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/tests/ui/consts/ptr_is_null.rs b/tests/ui/consts/ptr_is_null.rs index bbf1380231295..8b41f5718e8db 100644 --- a/tests/ui/consts/ptr_is_null.rs +++ b/tests/ui/consts/ptr_is_null.rs @@ -1,7 +1,6 @@ //@ compile-flags: --crate-type=lib //@ check-pass -#![feature(const_ptr_is_null)] #![allow(useless_ptr_null_checks)] const FOO: &usize = &42; From 543627ddbe82516d0a0e4beea64234ddf1b7c33d Mon Sep 17 00:00:00 2001 From: Ralf Jung Date: Sat, 16 Nov 2024 19:44:09 +0100 Subject: [PATCH 5/6] clean up const stability around UB checks --- library/core/src/intrinsics/mod.rs | 12 ++++++------ library/core/src/lib.rs | 2 +- library/core/src/ptr/mod.rs | 16 ++++++++-------- library/core/src/slice/raw.rs | 4 ++-- library/core/src/ub_checks.rs | 16 +++++++++------- 5 files changed, 26 insertions(+), 24 deletions(-) diff --git a/library/core/src/intrinsics/mod.rs b/library/core/src/intrinsics/mod.rs index 268af1c2965c5..a738b91dc1e19 100644 --- a/library/core/src/intrinsics/mod.rs +++ b/library/core/src/intrinsics/mod.rs @@ -4013,9 +4013,9 @@ pub const unsafe fn copy_nonoverlapping(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 +4119,8 @@ pub const unsafe fn copy(src: *const T, dst: *mut T, count: usize) { align: usize = align_of::(), 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 +4201,7 @@ pub const unsafe fn write_bytes(dst: *mut T, val: u8, count: usize) { addr: *const () = dst as *const (), align: usize = align_of::(), 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) } diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs index 1cacd1d2160aa..40e6774c7a8f6 100644 --- a/library/core/src/lib.rs +++ b/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)] @@ -131,7 +132,6 @@ #![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)] diff --git a/library/core/src/ptr/mod.rs b/library/core/src/ptr/mod.rs index 603e904421782..805edddfe6312 100644 --- a/library/core/src/ptr/mod.rs +++ b/library/core/src/ptr/mod.rs @@ -1103,9 +1103,9 @@ pub const unsafe fn swap_nonoverlapping(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(dst: *mut T, src: T) -> T { addr: *const () = dst as *const (), align: usize = align_of::(), 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(src: *const T) -> T { addr: *const () = src as *const (), align: usize = align_of::(), 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(dst: *mut T, src: T) { addr: *mut () = dst as *mut (), align: usize = align_of::(), 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(src: *const T) -> T { addr: *const () = src as *const (), align: usize = align_of::(), 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(dst: *mut T, src: T) { addr: *mut () = dst as *mut (), align: usize = align_of::(), 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); } diff --git a/library/core/src/slice/raw.rs b/library/core/src/slice/raw.rs index 89840881c4d90..319b76899bf8e 100644 --- a/library/core/src/slice/raw.rs +++ b/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::(), 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::(), 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) diff --git a/library/core/src/ub_checks.rs b/library/core/src/ub_checks.rs index e21cd3fcec6ce..3e6110c9c88a7 100644 --- a/library/core/src/ub_checks.rs +++ b/library/core/src/ub_checks.rs @@ -64,8 +64,6 @@ macro_rules! assert_unsafe_precondition { #[rustc_no_mir_inline] #[inline] #[rustc_nounwind] - #[cfg_attr(bootstrap, rustc_const_unstable(feature = "const_ub_checks", issue = "none"))] - #[rustc_allow_const_fn_unstable(const_ub_checks)] // only for UB checks const fn precondition_check($($name:$ty),*) { if !$e { ::core::panicking::panic_nounwind( @@ -116,12 +114,16 @@ pub(crate) const fn check_language_ub() -> bool { /// for `assert_unsafe_precondition!` with `check_language_ub`, in which case the /// check is anyway not executed in `const`. #[inline] -#[rustc_const_unstable(feature = "const_ub_checks", issue = "none")] -pub(crate) const fn is_aligned_and_not_null(ptr: *const (), align: usize, is_zst: bool) -> bool { +#[rustc_allow_const_fn_unstable(const_eval_select)] +pub(crate) const fn maybe_is_aligned_and_not_null( + ptr: *const (), + align: usize, + is_zst: bool, +) -> bool { // This is just for safety checks so we can const_eval_select. const_eval_select!( @capture { ptr: *const (), align: usize, is_zst: bool } -> bool: - if const #[rustc_const_unstable(feature = "const_ub_checks", issue = "none")] { + if const { is_zst || !ptr.is_null() } else { ptr.is_aligned_to(align) && (is_zst || !ptr.is_null()) @@ -141,8 +143,8 @@ pub(crate) const fn is_valid_allocation_size(size: usize, len: usize) -> bool { /// Note that in const-eval this function just returns `true` and therefore must /// only be used with `assert_unsafe_precondition!`, similar to `is_aligned_and_not_null`. #[inline] -#[rustc_const_unstable(feature = "const_ub_checks", issue = "none")] -pub(crate) const fn is_nonoverlapping( +#[rustc_allow_const_fn_unstable(const_eval_select)] +pub(crate) const fn maybe_is_nonoverlapping( src: *const (), dst: *const (), size: usize, From ec65dfc45ee9824a12ebb4c786469c91b94883ae Mon Sep 17 00:00:00 2001 From: Yutaro Ohno Date: Sun, 17 Nov 2024 15:12:53 +0900 Subject: [PATCH 6/6] alloc: fix `String`'s doc --- library/alloc/src/string.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs index b042720933b6d..e0576c2551545 100644 --- a/library/alloc/src/string.rs +++ b/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;