Auto merge of rust-lang#140565 - GuillaumeGomez:rollup-gv4ed14, r=GuillaumeGomez

Rollup of 12 pull requests

Successful merges:

 - rust-lang#138703 (chore: remove redundant words in comment)
 - rust-lang#139186 (Refactor `diy_float`)
 - rust-lang#139780 (docs: Add example to `Iterator::take` with `by_ref`)
 - rust-lang#139802 (Fix some grammar errors and hyperlinks in doc for `trait Allocator`)
 - rust-lang#140034 (simd_select_bitmask: the 'padding' bits in the mask are just ignored)
 - rust-lang#140062 (std: mention `remove_dir_all` can emit `DirectoryNotEmpty` when concurrently written into)
 - rust-lang#140420 (rustdoc: Fix doctest heuristic for main fn wrapping)
 - rust-lang#140460 (Fix handling of LoongArch target features not supported by LLVM 19)
 - rust-lang#140538 (rustc-dev-guide subtree update)
 - rust-lang#140544 (Clean up "const" situation in format_args!(). )
 - rust-lang#140552 (allow `#[rustc_std_internal_symbol]` in combination with `#[naked]`)
 - rust-lang#140556 (Improve error output in case `nodejs` or `npm` is not installed for rustdoc-gui test suite)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -273,6 +273,12 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
         ("aarch64", "fpmr") => None, // only existed in 18
         ("arm", "fp16") => Some(LLVMFeature::new("fullfp16")),
         // Filter out features that are not supported by the current LLVM version
+        ("loongarch64", "div32" | "lam-bh" | "lamcas" | "ld-seq-sa" | "scq")
+            if get_version().0 < 20 =>
+        {
+            None
+        }
+        // Filter out features that are not supported by the current LLVM version
         ("riscv32" | "riscv64", "zacas") if get_version().0 < 20 => None,
         // Enable the evex512 target feature if an avx512 target feature is enabled.
         ("x86", s) if s.starts_with("avx512") => {

compiler/rustc_const_eval/src/check_consts/ops.rs

@@ -352,7 +352,7 @@ fn build_error_for_const_call<'tcx>(
             );
             err
         }
-        _ if tcx.opt_parent(callee) == tcx.get_diagnostic_item(sym::ArgumentMethods) => {
+        _ if tcx.opt_parent(callee) == tcx.get_diagnostic_item(sym::FmtArgumentsNew) => {
             ccx.dcx().create_err(errors::NonConstFmtMacroCall {
                 span,
                 kind: ccx.const_kind(),

compiler/rustc_error_codes/src/error_codes/E0207.md

@@ -195,7 +195,7 @@ impl<'a> Contains for Foo {
 Please note that unconstrained lifetime parameters are not supported if they are
 being used by an associated type.
 
-In cases where the associated type's lifetime is meant to be tied to the the
+In cases where the associated type's lifetime is meant to be tied to the
 self type, and none of the methods on the trait need ownership or different
 mutability, then an option is to implement the trait on a borrowed type:
 

compiler/rustc_passes/src/check_attr.rs

@@ -625,6 +625,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             sym::naked,
             sym::instruction_set,
             sym::repr,
+            sym::rustc_std_internal_symbol,
             // code generation
             sym::cold,
             // documentation

compiler/rustc_span/src/symbol.rs

@@ -174,7 +174,6 @@ symbols! {
         Arc,
         ArcWeak,
         Argument,
-        ArgumentMethods,
         ArrayIntoIter,
         AsMut,
         AsRef,
@@ -249,6 +248,7 @@ symbols! {
         Error,
         File,
         FileType,
+        FmtArgumentsNew,
         Fn,
         FnMut,
         FnOnce,

compiler/rustc_target/src/target_features.rs

@@ -102,6 +102,9 @@ impl Stability {
 // check whether they're named already elsewhere in rust
 // e.g. in stdarch and whether the given name matches LLVM's
 // if it doesn't, to_llvm_feature in llvm_util in rustc_codegen_llvm needs to be adapted.
+// Additionally, if the feature is not available in older version of LLVM supported by the current
+// rust, the same function must be updated to filter out these features to avoid triggering
+// warnings.
 //
 // Also note that all target features listed here must be purely additive: for target_feature 1.1 to
 // be sound, we can never allow features like `+soft-float` (on x86) to be controlled on a

library/core/src/alloc/mod.rs

@@ -90,7 +90,7 @@ impl fmt::Display for AllocError {
 /// # Safety
 ///
 /// Memory blocks that are [*currently allocated*] by an allocator,
-/// must point to valid memory, and retain their validity while until either:
+/// must point to valid memory, and retain their validity until either:
 ///  - the memory block is deallocated, or
 ///  - the allocator is dropped.
 ///
@@ -112,7 +112,9 @@ pub unsafe trait Allocator {
     ///
     /// The returned block of memory remains valid as long as it is [*currently allocated*] and the shorter of:
     ///   - the borrow-checker lifetime of the allocator type itself.
-    ///   - as long as at the allocator and all its clones has not been dropped.
+    ///   - as long as the allocator and all its clones have not been dropped.
+    ///
+    /// [*currently allocated*]: #currently-allocated-memory
     ///
     /// # Errors
     ///

library/core/src/fmt/mod.rs

@@ -622,44 +622,9 @@ pub struct Arguments<'a> {
     args: &'a [rt::Argument<'a>],
 }
 
-/// Used by the format_args!() macro to create a fmt::Arguments object.
 #[doc(hidden)]
 #[unstable(feature = "fmt_internals", issue = "none")]
 impl<'a> Arguments<'a> {
-    #[inline]
-    pub const fn new_const<const N: usize>(pieces: &'a [&'static str; N]) -> Self {
-        const { assert!(N <= 1) };
-        Arguments { pieces, fmt: None, args: &[] }
-    }
-
-    /// When using the format_args!() macro, this function is used to generate the
-    /// Arguments structure.
-    #[inline]
-    pub const fn new_v1<const P: usize, const A: usize>(
-        pieces: &'a [&'static str; P],
-        args: &'a [rt::Argument<'a>; A],
-    ) -> Arguments<'a> {
-        const { assert!(P >= A && P <= A + 1, "invalid args") }
-        Arguments { pieces, fmt: None, args }
-    }
-
-    /// Specifies nonstandard formatting parameters.
-    ///
-    /// An `rt::UnsafeArg` is required because the following invariants must be held
-    /// in order for this function to be safe:
-    /// 1. The `pieces` slice must be at least as long as `fmt`.
-    /// 2. Every `rt::Placeholder::position` value within `fmt` must be a valid index of `args`.
-    /// 3. Every `rt::Count::Param` within `fmt` must contain a valid index of `args`.
-    #[inline]
-    pub const fn new_v1_formatted(
-        pieces: &'a [&'static str],
-        args: &'a [rt::Argument<'a>],
-        fmt: &'a [rt::Placeholder],
-        _unsafe_arg: rt::UnsafeArg,
-    ) -> Arguments<'a> {
-        Arguments { pieces, fmt: Some(fmt), args }
-    }
-
     /// Estimates the length of the formatted text.
     ///
     /// This is intended to be used for setting initial `String` capacity

library/core/src/fmt/rt.rs

@@ -1,7 +1,10 @@
 #![allow(missing_debug_implementations)]
 #![unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
 
-//! These are the lang items used by format_args!().
+//! All types and methods in this file are used by the compiler in
+//! the expansion/lowering of format_args!().
+//!
+//! Do not modify them without understanding the consequences for the format_args!() macro.
 
 use super::*;
 use crate::hint::unreachable_unchecked;
@@ -110,46 +113,45 @@ macro_rules! argument_new {
     };
 }
 
-#[rustc_diagnostic_item = "ArgumentMethods"]
 impl Argument<'_> {
     #[inline]
-    pub fn new_display<T: Display>(x: &T) -> Argument<'_> {
+    pub const fn new_display<T: Display>(x: &T) -> Argument<'_> {
         argument_new!(T, x, <T as Display>::fmt)
     }
     #[inline]
-    pub fn new_debug<T: Debug>(x: &T) -> Argument<'_> {
+    pub const fn new_debug<T: Debug>(x: &T) -> Argument<'_> {
         argument_new!(T, x, <T as Debug>::fmt)
     }
     #[inline]
-    pub fn new_debug_noop<T: Debug>(x: &T) -> Argument<'_> {
+    pub const fn new_debug_noop<T: Debug>(x: &T) -> Argument<'_> {
         argument_new!(T, x, |_: &T, _| Ok(()))
     }
     #[inline]
-    pub fn new_octal<T: Octal>(x: &T) -> Argument<'_> {
+    pub const fn new_octal<T: Octal>(x: &T) -> Argument<'_> {
         argument_new!(T, x, <T as Octal>::fmt)
     }
     #[inline]
-    pub fn new_lower_hex<T: LowerHex>(x: &T) -> Argument<'_> {
+    pub const fn new_lower_hex<T: LowerHex>(x: &T) -> Argument<'_> {
         argument_new!(T, x, <T as LowerHex>::fmt)
     }
     #[inline]
-    pub fn new_upper_hex<T: UpperHex>(x: &T) -> Argument<'_> {
+    pub const fn new_upper_hex<T: UpperHex>(x: &T) -> Argument<'_> {
         argument_new!(T, x, <T as UpperHex>::fmt)
     }
     #[inline]
-    pub fn new_pointer<T: Pointer>(x: &T) -> Argument<'_> {
+    pub const fn new_pointer<T: Pointer>(x: &T) -> Argument<'_> {
         argument_new!(T, x, <T as Pointer>::fmt)
     }
     #[inline]
-    pub fn new_binary<T: Binary>(x: &T) -> Argument<'_> {
+    pub const fn new_binary<T: Binary>(x: &T) -> Argument<'_> {
         argument_new!(T, x, <T as Binary>::fmt)
     }
     #[inline]
-    pub fn new_lower_exp<T: LowerExp>(x: &T) -> Argument<'_> {
+    pub const fn new_lower_exp<T: LowerExp>(x: &T) -> Argument<'_> {
         argument_new!(T, x, <T as LowerExp>::fmt)
     }
     #[inline]
-    pub fn new_upper_exp<T: UpperExp>(x: &T) -> Argument<'_> {
+    pub const fn new_upper_exp<T: UpperExp>(x: &T) -> Argument<'_> {
         argument_new!(T, x, <T as UpperExp>::fmt)
     }
     #[inline]
@@ -200,15 +202,8 @@ impl Argument<'_> {
     /// let f = format_args!("{}", "a");
     /// println!("{f}");
     /// ```
-    ///
-    /// This function should _not_ be const, to make sure we don't accept
-    /// format_args!() and panic!() with arguments in const, even when not evaluated:
-    ///
-    /// ```compile_fail,E0015
-    /// const _: () = if false { panic!("a {}", "a") };
-    /// ```
     #[inline]
-    pub fn none() -> [Self; 0] {
+    pub const fn none() -> [Self; 0] {
         []
     }
 }
@@ -229,3 +224,57 @@ impl UnsafeArg {
         Self { _private: () }
     }
 }
+
+/// Used by the format_args!() macro to create a fmt::Arguments object.
+#[doc(hidden)]
+#[unstable(feature = "fmt_internals", issue = "none")]
+#[rustc_diagnostic_item = "FmtArgumentsNew"]
+impl<'a> Arguments<'a> {
+    #[inline]
+    pub const fn new_const<const N: usize>(pieces: &'a [&'static str; N]) -> Self {
+        const { assert!(N <= 1) };
+        Arguments { pieces, fmt: None, args: &[] }
+    }
+
+    /// When using the format_args!() macro, this function is used to generate the
+    /// Arguments structure.
+    ///
+    /// This function should _not_ be const, to make sure we don't accept
+    /// format_args!() and panic!() with arguments in const, even when not evaluated:
+    ///
+    /// ```compile_fail,E0015
+    /// const _: () = if false { panic!("a {}", "a") };
+    /// ```
+    #[inline]
+    pub fn new_v1<const P: usize, const A: usize>(
+        pieces: &'a [&'static str; P],
+        args: &'a [rt::Argument<'a>; A],
+    ) -> Arguments<'a> {
+        const { assert!(P >= A && P <= A + 1, "invalid args") }
+        Arguments { pieces, fmt: None, args }
+    }
+
+    /// Specifies nonstandard formatting parameters.
+    ///
+    /// An `rt::UnsafeArg` is required because the following invariants must be held
+    /// in order for this function to be safe:
+    /// 1. The `pieces` slice must be at least as long as `fmt`.
+    /// 2. Every `rt::Placeholder::position` value within `fmt` must be a valid index of `args`.
+    /// 3. Every `rt::Count::Param` within `fmt` must contain a valid index of `args`.
+    ///
+    /// This function should _not_ be const, to make sure we don't accept
+    /// format_args!() and panic!() with arguments in const, even when not evaluated:
+    ///
+    /// ```compile_fail,E0015
+    /// const _: () = if false { panic!("a {:1}", "a") };
+    /// ```
+    #[inline]
+    pub fn new_v1_formatted(
+        pieces: &'a [&'static str],
+        args: &'a [rt::Argument<'a>],
+        fmt: &'a [rt::Placeholder],
+        _unsafe_arg: rt::UnsafeArg,
+    ) -> Arguments<'a> {
+        Arguments { pieces, fmt: Some(fmt), args }
+    }
+}

library/core/src/intrinsics/simd.rs

@@ -577,11 +577,9 @@ pub unsafe fn simd_select<M, T>(mask: M, if_true: T, if_false: T) -> T;
 /// For each element, if the bit in `mask` is `1`, select the element from
 /// `if_true`.  If the corresponding bit in `mask` is `0`, select the element from
 /// `if_false`.
+/// The remaining bits of the mask are ignored.
 ///
 /// The bitmask bit order matches `simd_bitmask`.
-///
-/// # Safety
-/// Padding bits must be all zero.
 #[rustc_intrinsic]
 #[rustc_nounwind]
 pub unsafe fn simd_select_bitmask<M, T>(m: M, yes: T, no: T) -> T;

library/core/src/iter/traits/iterator.rs

@@ -1340,6 +1340,24 @@ pub trait Iterator {
     /// assert_eq!(iter.next(), Some(2));
     /// assert_eq!(iter.next(), None);
     /// ```
+    ///
+    /// Use [`by_ref`] to take from the iterator without consuming it, and then
+    /// continue using the original iterator:
+    ///
+    /// ```
+    /// let mut words = ["hello", "world", "of", "Rust"].into_iter();
+    ///
+    /// // Take the first two words.
+    /// let hello_world: Vec<_> = words.by_ref().take(2).collect();
+    /// assert_eq!(hello_world, vec!["hello", "world"]);
+    ///
+    /// // Collect the rest of the words.
+    /// // We can only do this because we used `by_ref` earlier.
+    /// let of_rust: Vec<_> = words.collect();
+    /// assert_eq!(of_rust, vec!["of", "Rust"]);
+    /// ```
+    ///
+    /// [`by_ref`]: Iterator::by_ref
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn take(self, n: usize) -> Take<Self>

library/core/src/macros/mod.rs

@@ -1748,8 +1748,8 @@ pub(crate) mod builtin {
         /* compiler built-in */
     }
 
-    /// Provide a list of type aliases and other opaque-type-containing type definitions.
-    /// This list will be used in the body of the item it is applied to define opaque
+    /// Provide a list of type aliases and other opaque-type-containing type definitions
+    /// to an item with a body. This list will be used in that body to define opaque
     /// types' hidden types.
     /// Can only be applied to things that have bodies.
     #[unstable(

library/core/src/num/diy_float.rs

@@ -21,61 +21,29 @@ pub struct Fp {
 
 impl Fp {
     /// Returns a correctly rounded product of itself and `other`.
-    pub fn mul(&self, other: &Fp) -> Fp {
-        const MASK: u64 = 0xffffffff;
-        let a = self.f >> 32;
-        let b = self.f & MASK;
-        let c = other.f >> 32;
-        let d = other.f & MASK;
-        let ac = a * c;
-        let bc = b * c;
-        let ad = a * d;
-        let bd = b * d;
-        let tmp = (bd >> 32) + (ad & MASK) + (bc & MASK) + (1 << 31) /* round */;
-        let f = ac + (ad >> 32) + (bc >> 32) + (tmp >> 32);
+    pub fn mul(self, other: Self) -> Self {
+        let (lo, hi) = self.f.widening_mul(other.f);
+        let f = hi + (lo >> 63) /* round */;
         let e = self.e + other.e + 64;
-        Fp { f, e }
+        Self { f, e }
     }
 
     /// Normalizes itself so that the resulting mantissa is at least `2^63`.
-    pub fn normalize(&self) -> Fp {
-        let mut f = self.f;
-        let mut e = self.e;
-        if f >> (64 - 32) == 0 {
-            f <<= 32;
-            e -= 32;
-        }
-        if f >> (64 - 16) == 0 {
-            f <<= 16;
-            e -= 16;
-        }
-        if f >> (64 - 8) == 0 {
-            f <<= 8;
-            e -= 8;
-        }
-        if f >> (64 - 4) == 0 {
-            f <<= 4;
-            e -= 4;
-        }
-        if f >> (64 - 2) == 0 {
-            f <<= 2;
-            e -= 2;
-        }
-        if f >> (64 - 1) == 0 {
-            f <<= 1;
-            e -= 1;
-        }
+    pub fn normalize(self) -> Self {
+        let lz = self.f.leading_zeros();
+        let f = self.f << lz;
+        let e = self.e - lz as i16;
         debug_assert!(f >= (1 << 63));
-        Fp { f, e }
+        Self { f, e }
     }
 
     /// Normalizes itself to have the shared exponent.
     /// It can only decrease the exponent (and thus increase the mantissa).
-    pub fn normalize_to(&self, e: i16) -> Fp {
+    pub fn normalize_to(self, e: i16) -> Self {
         let edelta = self.e - e;
         assert!(edelta >= 0);
         let edelta = edelta as usize;
         assert_eq!(self.f << edelta >> edelta, self.f);
-        Fp { f: self.f << edelta, e }
+        Self { f: self.f << edelta, e }
     }
 }