Merge ref '5a30e4307f05' from rust-lang/rust

Pull recent changes from https://github.com/rust-lang/rust via Josh.

Upstream ref: 5a30e43
Filtered ref: 59749e9f8c765d3021796a9fe0c188643c4b8d77

This merge was created using https://github.com/rust-lang/josh-sync.

Author: Kobzol

Cargo.lock

@@ -5,7 +5,7 @@
 use core::error::Error;
 use core::fmt::{self, Debug, Display, Formatter};
 #[cfg(not(no_global_oom_handling))]
-use core::intrinsics::const_allocate;
+use core::intrinsics::{const_allocate, const_make_global};
 use core::marker::PhantomData;
 #[cfg(not(no_global_oom_handling))]
 use core::marker::Unsize;
@@ -340,9 +340,10 @@ impl<H> WithHeader<H> {
                     alloc.add(metadata_offset).cast();
                 // SAFETY: `*metadata_ptr` is within the allocation.
                 metadata_ptr.write(ptr::metadata::<Dyn>(ptr::dangling::<T>() as *const Dyn));
-
+                // SAFETY: valid heap allocation
+                const_make_global(alloc);
                 // SAFETY: we have just written the metadata.
-                &*(metadata_ptr)
+                &*metadata_ptr
             }
         };
 

alloc/src/boxed/thin.rs

@@ -192,7 +192,7 @@ impl<T, A: Allocator> Drop for Drain<'_, T, A> {
                     // this branch is never taken.
                     // We use `#[cold]` instead of `#[inline(never)]`, because inlining this
                     // function into the general case (`.drain(n..m)`) is fine.
-                    // See `tests/codegen/vecdeque-drain.rs` for a test.
+                    // See `tests/codegen-llvm/vecdeque-drain.rs` for a test.
                     #[cold]
                     fn join_head_and_tail_wrapping<T, A: Allocator>(
                         source_deque: &mut VecDeque<T, A>,

alloc/src/collections/vec_deque/drain.rs

@@ -348,13 +348,13 @@
 //! format := '{' [ argument ] [ ':' format_spec ] [ ws ] * '}'
 //! argument := integer | identifier
 //!
-//! format_spec := [[fill]align][sign]['#']['0'][width]['.' precision]type
+//! format_spec := [[fill]align][sign]['#']['0'][width]['.' precision][type]
 //! fill := character
 //! align := '<' | '^' | '>'
 //! sign := '+' | '-'
 //! width := count
 //! precision := count | '*'
-//! type := '' | '?' | 'x?' | 'X?' | identifier
+//! type := '?' | 'x?' | 'X?' | identifier
 //! count := parameter | integer
 //! parameter := argument '$'
 //! ```

alloc/src/fmt.rs

@@ -107,8 +107,10 @@
 #![feature(char_max_len)]
 #![feature(clone_to_uninit)]
 #![feature(coerce_unsized)]
+#![feature(const_default)]
 #![feature(const_eval_select)]
 #![feature(const_heap)]
+#![feature(const_trait_impl)]
 #![feature(core_intrinsics)]
 #![feature(deprecated_suggestion)]
 #![feature(deref_pure_trait)]
@@ -153,6 +155,7 @@
 #![feature(try_trait_v2)]
 #![feature(try_with_capacity)]
 #![feature(tuple_trait)]
+#![feature(ub_checks)]
 #![feature(unicode_internals)]
 #![feature(unsize)]
 #![feature(unwrap_infallible)]

alloc/src/lib.rs

@@ -761,7 +761,7 @@ impl<A: Allocator> RawVecInner<A> {
 }
 
 // not marked inline(never) since we want optimizers to be able to observe the specifics of this
-// function, see tests/codegen/vec-reserve-extend.rs.
+// function, see tests/codegen-llvm/vec-reserve-extend.rs.
 #[cold]
 fn finish_grow<A>(
     new_layout: Layout,

alloc/src/raw_vec/mod.rs

@@ -2611,7 +2611,8 @@ impl_eq! { Cow<'a, str>, &'b str }
 impl_eq! { Cow<'a, str>, String }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl Default for String {
+#[rustc_const_unstable(feature = "const_default", issue = "143894")]
+impl const Default for String {
     /// Creates an empty `String`.
     #[inline]
     fn default() -> String {

alloc/src/string.rs

@@ -64,7 +64,7 @@ use core::mem::{self, ManuallyDrop, MaybeUninit, SizedTypeProperties};
 use core::ops::{self, Index, IndexMut, Range, RangeBounds};
 use core::ptr::{self, NonNull};
 use core::slice::{self, SliceIndex};
-use core::{fmt, intrinsics};
+use core::{fmt, intrinsics, ub_checks};
 
 #[stable(feature = "extract_if", since = "1.87.0")]
 pub use self::extract_if::ExtractIf;
@@ -1058,6 +1058,11 @@ impl<T, A: Allocator> Vec<T, A> {
     #[inline]
     #[unstable(feature = "allocator_api", issue = "32838")]
     pub unsafe fn from_raw_parts_in(ptr: *mut T, length: usize, capacity: usize, alloc: A) -> Self {
+        ub_checks::assert_unsafe_precondition!(
+            check_library_ub,
+            "Vec::from_raw_parts_in requires that length <= capacity",
+            (length: usize = length, capacity: usize = capacity) => length <= capacity
+        );
         unsafe { Vec { buf: RawVec::from_raw_parts_in(ptr, capacity, alloc), len: length } }
     }
 
@@ -1174,6 +1179,11 @@ impl<T, A: Allocator> Vec<T, A> {
     #[unstable(feature = "allocator_api", reason = "new API", issue = "32838")]
     // #[unstable(feature = "box_vec_non_null", issue = "130364")]
     pub unsafe fn from_parts_in(ptr: NonNull<T>, length: usize, capacity: usize, alloc: A) -> Self {
+        ub_checks::assert_unsafe_precondition!(
+            check_library_ub,
+            "Vec::from_parts_in requires that length <= capacity",
+            (length: usize = length, capacity: usize = capacity) => length <= capacity
+        );
         unsafe { Vec { buf: RawVec::from_nonnull_in(ptr, capacity, alloc), len: length } }
     }
 
@@ -1950,7 +1960,11 @@ impl<T, A: Allocator> Vec<T, A> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub unsafe fn set_len(&mut self, new_len: usize) {
-        debug_assert!(new_len <= self.capacity());
+        ub_checks::assert_unsafe_precondition!(
+            check_library_ub,
+            "Vec::set_len requires that new_len <= capacity()",
+            (new_len: usize = new_len, capacity: usize = self.capacity()) => new_len <= capacity
+        );
 
         self.len = new_len;
     }
@@ -3695,7 +3709,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// This is optimal if:
     ///
     /// * The tail (elements in the vector after `range`) is empty,
-    /// * or `replace_with` yields fewer or equal elements than `range`’s length
+    /// * or `replace_with` yields fewer or equal elements than `range`'s length
     /// * or the lower bound of its `size_hint()` is exact.
     ///
     /// Otherwise, a temporary vector is allocated and the tail is moved twice.
@@ -3895,7 +3909,8 @@ unsafe impl<#[may_dangle] T, A: Allocator> Drop for Vec<T, A> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T> Default for Vec<T> {
+#[rustc_const_unstable(feature = "const_default", issue = "143894")]
+impl<T> const Default for Vec<T> {
     /// Creates an empty `Vec<T>`.
     ///
     /// The vector will not allocate until elements are pushed onto it.

alloc/src/vec/mod.rs

@@ -195,6 +195,25 @@ jobs:
       run: ./ci/update-musl.sh
     - run: cargo clippy --workspace --all-targets
 
+  build-custom:
+    name: Build custom target
+    runs-on: ubuntu-24.04
+    timeout-minutes: 10
+    steps:
+    - uses: actions/checkout@v4
+    - name: Install Rust
+      run: |
+        rustup update nightly --no-self-update
+        rustup default nightly
+        rustup component add rust-src
+    - uses: Swatinem/rust-cache@v2
+    - run: |
+        # Ensure we can build with custom target.json files (these can interact
+        # poorly with build scripts)
+        cargo build -p compiler_builtins -p libm \
+          --target etc/thumbv7em-none-eabi-renamed.json \
+          -Zbuild-std=core
+
   benchmarks:
     name: Benchmarks
     timeout-minutes: 20
@@ -331,6 +350,7 @@ jobs:
   success:
     needs:
       - benchmarks
+      - build-custom
       - clippy
       - extensive
       - miri

compiler-builtins/.github/workflows/main.yaml

@@ -0,0 +1,23 @@
+# Perform a subtree sync (pull) using the josh-sync tool once every few days (or on demand).
+name: rustc-pull
+
+on:
+  workflow_dispatch:
+  schedule:
+    # Run at 04:00 UTC every Monday and Thursday
+    - cron: '0 4 * * 1,4'
+
+jobs:
+  pull:
+    if: github.repository == 'rust-lang/compiler-builtins'
+    uses: rust-lang/josh-sync/.github/workflows/rustc-pull.yml@main
+    with:
+      # https://rust-lang.zulipchat.com/#narrow/channel/219381-t-libs/topic/compiler-builtins.20subtree.20sync.20automation/with/528482375
+      zulip-stream-id: 219381
+      zulip-topic: 'compiler-builtins subtree sync automation'
+      zulip-bot-email:  "[email protected]"
+      pr-base-branch: master
+      branch-name: rustc-pull
+    secrets:
+      zulip-api-token: ${{ secrets.ZULIP_API_TOKEN }}
+      token: ${{ secrets.GITHUB_TOKEN }}