viirya commented on PR #2883:
URL: https://github.com/apache/arrow-rs/pull/2883#issuecomment-1279885113
> Where is this called, I think I am being blind. It looks like this PR
removes the alignment check in PrimitiveArray?
Hmm? No, this PR doesn't remove it.
Let me quote what I saw for now:
```rust
pub fn values(&self) -> &[T::Native] {
// Soundness
// raw_values alignment & location is ensured by fn
from(ArrayDataRef)
// buffer bounds/offset is ensured by the ArrayData instance.
unsafe {
std::slice::from_raw_parts(
self.raw_values.as_ptr().add(self.data.offset()),
self.len(),
)
}
}
```
```rust
pub const unsafe fn from_raw_parts<'a, T>(data: *const T, len: usize) -> &'a
[T] {
// SAFETY: the caller must uphold the safety contract for
`from_raw_parts`.
unsafe {
assert_unsafe_precondition!(
is_aligned_and_not_null(data)
&& crate::mem::size_of::<T>().saturating_mul(len) <=
isize::MAX as usize
);
&*ptr::slice_from_raw_parts(data, len)
}
}
```
```rust
pub(crate) fn is_aligned_and_not_null<T>(ptr: *const T) -> bool {
!ptr.is_null() && ptr.addr() % mem::align_of::<T>() == 0
}
```
BTW, I'm on a M1 Macbook so the toolchain is stable-aarch64-apple-darwin.
Maybe you will see something different?
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