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Rollup merge of rust-lang#100820 - WaffleLapkin:use_ptr_is_aligned_me…
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…thods, r=scottmcm

Use pointer `is_aligned*` methods

This PR replaces some manual alignment checks with calls to `pointer::{is_aligned, is_aligned_to}` and removes a useless pointer cast.

r? `@scottmcm`

_split off from #100746_
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matthiaskrgr authored Aug 21, 2022
2 parents e211509 + de9da0b commit 4b880d5
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Showing 5 changed files with 9 additions and 8 deletions.
2 changes: 1 addition & 1 deletion library/alloc/src/vec/into_iter.rs
Original file line number Diff line number Diff line change
Expand Up @@ -148,7 +148,7 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> {

#[inline]
fn next(&mut self) -> Option<T> {
if self.ptr as *const _ == self.end {
if self.ptr == self.end {
None
} else if mem::size_of::<T>() == 0 {
// purposefully don't use 'ptr.offset' because for
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1 change: 1 addition & 0 deletions library/alloc/tests/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,7 @@
#![feature(const_str_from_utf8)]
#![feature(nonnull_slice_from_raw_parts)]
#![feature(panic_update_hook)]
#![feature(pointer_is_aligned)]
#![feature(slice_flatten)]
#![feature(thin_box)]
#![feature(bench_black_box)]
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8 changes: 4 additions & 4 deletions library/alloc/tests/thin_box.rs
Original file line number Diff line number Diff line change
Expand Up @@ -48,11 +48,11 @@ fn verify_aligned<T>(ptr: *const T) {
// practice these checks are mostly just smoke-detectors for an extremely
// broken `ThinBox` impl, since it's an extremely subtle piece of code.
let ptr = core::hint::black_box(ptr);
let align = core::mem::align_of::<T>();
assert!(
(ptr.addr() & (align - 1)) == 0 && !ptr.is_null(),
"misaligned ThinBox data; valid pointers to `{}` should be aligned to {align}: {ptr:p}",
core::any::type_name::<T>(),
ptr.is_aligned() && !ptr.is_null(),
"misaligned ThinBox data; valid pointers to `{ty}` should be aligned to {align}: {ptr:p}",
ty = core::any::type_name::<T>(),
align = core::mem::align_of::<T>(),
);
}

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2 changes: 1 addition & 1 deletion library/core/src/intrinsics.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2139,7 +2139,7 @@ pub(crate) use assert_unsafe_precondition;
/// Checks whether `ptr` is properly aligned with respect to
/// `align_of::<T>()`.
pub(crate) fn is_aligned_and_not_null<T>(ptr: *const T) -> bool {
!ptr.is_null() && ptr.addr() % mem::align_of::<T>() == 0
!ptr.is_null() && ptr.is_aligned()
}

/// Checks whether the regions of memory starting at `src` and `dst` of size
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4 changes: 2 additions & 2 deletions library/std/src/sys/sgx/abi/usercalls/alloc.rs
Original file line number Diff line number Diff line change
Expand Up @@ -117,7 +117,7 @@ pub unsafe trait UserSafe {
/// * the pointer is null.
/// * the pointed-to range is not in user memory.
unsafe fn check_ptr(ptr: *const Self) {
let is_aligned = |p: *const u8| -> bool { 0 == p.addr() & (Self::align_of() - 1) };
let is_aligned = |p: *const u8| -> bool { p.is_aligned_to(Self::align_of()) };

assert!(is_aligned(ptr as *const u8));
assert!(is_user_range(ptr as _, mem::size_of_val(unsafe { &*ptr })));
Expand Down Expand Up @@ -386,7 +386,7 @@ pub(crate) unsafe fn copy_to_userspace(src: *const u8, dst: *mut u8, len: usize)
unsafe {
copy_bytewise_to_userspace(src, dst, len);
}
} else if len % 8 == 0 && dst as usize % 8 == 0 {
} else if len % 8 == 0 && dst.is_aligned_to(8) {
// Copying 8-byte aligned quadwords: copy quad word per quad word
unsafe {
copy_quadwords(src, dst, len);
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