Merging upstream version 1.71.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 33 insertions, 0 deletions

diff --git a/compiler/rustc_data_structures/src/aligned.rs b/compiler/rustc_data_structures/src/aligned.rs
new file mode 100644
index 000000000..0e5ecfd9b
--- /dev/null
+++ b/compiler/rustc_data_structures/src/aligned.rs
@@ -0,0 +1,33 @@
+use std::ptr::Alignment;
+
+/// Returns the ABI-required minimum alignment of a type in bytes.
+///
+/// This is equivalent to [`mem::align_of`], but also works for some unsized
+/// types (e.g. slices or rustc's `List`s).
+///
+/// [`mem::align_of`]: std::mem::align_of
+pub const fn align_of<T: ?Sized + Aligned>() -> Alignment {
+    T::ALIGN
+}
+
+/// A type with a statically known alignment.
+///
+/// # Safety
+///
+/// `Self::ALIGN` must be equal to the alignment of `Self`. For sized types it
+/// is [`mem::align_of<Self>()`], for unsized types it depends on the type, for
+/// example `[T]` has alignment of `T`.
+///
+/// [`mem::align_of<Self>()`]: std::mem::align_of
+pub unsafe trait Aligned {
+    /// Alignment of `Self`.
+    const ALIGN: Alignment;
+}
+
+unsafe impl<T> Aligned for T {
+    const ALIGN: Alignment = Alignment::of::<Self>();
+}
+
+unsafe impl<T> Aligned for [T] {
+    const ALIGN: Alignment = Alignment::of::<T>();
+}