1 files changed, 142 insertions, 0 deletions
diff --git a/third_party/rust/bytemuck/src/zeroable.rs b/third_party/rust/bytemuck/src/zeroable.rs
new file mode 100644
index 0000000000..fb9620431e
--- /dev/null
+++ b/third_party/rust/bytemuck/src/zeroable.rs
@@ -0,0 +1,142 @@
+use super::*;
+
+/// Trait for types that can be safely created with
+/// [`zeroed`](core::mem::zeroed).
+///
+/// An all-zeroes value may or may not be the same value as the
+/// [Default](core::default::Default) value of the type.
+///
+/// ## Safety
+///
+/// * Your type must be inhabited (eg: no
+///   [Infallible](core::convert::Infallible)).
+/// * Your type must be allowed to be an "all zeroes" bit pattern (eg: no
+///   [`NonNull<T>`](core::ptr::NonNull)).
+pub unsafe trait Zeroable: Sized {
+  /// Calls [`zeroed`](core::mem::zeroed).
+  ///
+  /// This is a trait method so that you can write `MyType::zeroed()` in your
+  /// code. It is a contract of this trait that if you implement it on your type
+  /// you **must not** override this method.
+  #[inline]
+  fn zeroed() -> Self {
+    unsafe { core::mem::zeroed() }
+  }
+}
+unsafe impl Zeroable for () {}
+unsafe impl Zeroable for bool {}
+unsafe impl Zeroable for char {}
+unsafe impl Zeroable for u8 {}
+unsafe impl Zeroable for i8 {}
+unsafe impl Zeroable for u16 {}
+unsafe impl Zeroable for i16 {}
+unsafe impl Zeroable for u32 {}
+unsafe impl Zeroable for i32 {}
+unsafe impl Zeroable for u64 {}
+unsafe impl Zeroable for i64 {}
+unsafe impl Zeroable for usize {}
+unsafe impl Zeroable for isize {}
+unsafe impl Zeroable for u128 {}
+unsafe impl Zeroable for i128 {}
+unsafe impl Zeroable for f32 {}
+unsafe impl Zeroable for f64 {}
+unsafe impl<T: Zeroable> Zeroable for Wrapping<T> {}
+
+unsafe impl Zeroable for Option<NonZeroI8> {}
+unsafe impl Zeroable for Option<NonZeroI16> {}
+unsafe impl Zeroable for Option<NonZeroI32> {}
+unsafe impl Zeroable for Option<NonZeroI64> {}
+unsafe impl Zeroable for Option<NonZeroI128> {}
+unsafe impl Zeroable for Option<NonZeroIsize> {}
+unsafe impl Zeroable for Option<NonZeroU8> {}
+unsafe impl Zeroable for Option<NonZeroU16> {}
+unsafe impl Zeroable for Option<NonZeroU32> {}
+unsafe impl Zeroable for Option<NonZeroU64> {}
+unsafe impl Zeroable for Option<NonZeroU128> {}
+unsafe impl Zeroable for Option<NonZeroUsize> {}
+
+unsafe impl<T> Zeroable for *mut T {}
+unsafe impl<T> Zeroable for *const T {}
+unsafe impl<T> Zeroable for Option<NonNull<T>> {}
+unsafe impl<T: Zeroable> Zeroable for PhantomData<T> {}
+unsafe impl<T: Zeroable> Zeroable for ManuallyDrop<T> {}
+
+// 2.0: add MaybeUninit
+//unsafe impl<T> Zeroable for MaybeUninit<T> {}
+
+unsafe impl<A: Zeroable> Zeroable for (A,) {}
+unsafe impl<A: Zeroable, B: Zeroable> Zeroable for (A, B) {}
+unsafe impl<A: Zeroable, B: Zeroable, C: Zeroable> Zeroable for (A, B, C) {}
+unsafe impl<A: Zeroable, B: Zeroable, C: Zeroable, D: Zeroable> Zeroable
+  for (A, B, C, D)
+{
+}
+unsafe impl<A: Zeroable, B: Zeroable, C: Zeroable, D: Zeroable, E: Zeroable>
+  Zeroable for (A, B, C, D, E)
+{
+}
+unsafe impl<
+    A: Zeroable,
+    B: Zeroable,
+    C: Zeroable,
+    D: Zeroable,
+    E: Zeroable,
+    F: Zeroable,
+  > Zeroable for (A, B, C, D, E, F)
+{
+}
+unsafe impl<
+    A: Zeroable,
+    B: Zeroable,
+    C: Zeroable,
+    D: Zeroable,
+    E: Zeroable,
+    F: Zeroable,
+    G: Zeroable,
+  > Zeroable for (A, B, C, D, E, F, G)
+{
+}
+unsafe impl<
+    A: Zeroable,
+    B: Zeroable,
+    C: Zeroable,
+    D: Zeroable,
+    E: Zeroable,
+    F: Zeroable,
+    G: Zeroable,
+    H: Zeroable,
+  > Zeroable for (A, B, C, D, E, F, G, H)
+{
+}
+
+impl_unsafe_marker_for_array!(
+  Zeroable, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
+  19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 48, 64, 96, 128, 256,
+  512, 1024, 2048, 4096
+);
+
+#[cfg(target_arch = "x86")]
+unsafe impl Zeroable for x86::__m128i {}
+#[cfg(target_arch = "x86")]
+unsafe impl Zeroable for x86::__m128 {}
+#[cfg(target_arch = "x86")]
+unsafe impl Zeroable for x86::__m128d {}
+#[cfg(target_arch = "x86")]
+unsafe impl Zeroable for x86::__m256i {}
+#[cfg(target_arch = "x86")]
+unsafe impl Zeroable for x86::__m256 {}
+#[cfg(target_arch = "x86")]
+unsafe impl Zeroable for x86::__m256d {}
+
+#[cfg(target_arch = "x86_64")]
+unsafe impl Zeroable for x86_64::__m128i {}
+#[cfg(target_arch = "x86_64")]
+unsafe impl Zeroable for x86_64::__m128 {}
+#[cfg(target_arch = "x86_64")]
+unsafe impl Zeroable for x86_64::__m128d {}
+#[cfg(target_arch = "x86_64")]
+unsafe impl Zeroable for x86_64::__m256i {}
+#[cfg(target_arch = "x86_64")]
+unsafe impl Zeroable for x86_64::__m256 {}
+#[cfg(target_arch = "x86_64")]
+unsafe impl Zeroable for x86_64::__m256d {}