// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
//
// Copyright 2024 The Fuchsia Authors
//
// Licensed under the 2-Clause BSD License <LICENSE-BSD or
// https://opensource.org/license/bsd-2-clause>, Apache License, Version 2.0
// <LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0>, or the MIT
// license <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your option.
// This file may not be copied, modified, or distributed except according to
// those terms.
use core::{
cell::{Cell, UnsafeCell},
mem::MaybeUninit as CoreMaybeUninit,
ptr::NonNull,
};
use super::*;
use crate::pointer::cast::{CastSizedExact, CastUnsized};
// SAFETY: Per the reference [1], "the unit tuple (`()`) ... is guaranteed as a
// zero-sized type to have a size of 0 and an alignment of 1."
// - `Immutable`: `()` self-evidently does not contain any `UnsafeCell`s.
// - `TryFromBytes` (with no validator), `FromZeros`, `FromBytes`: There is only
// one possible sequence of 0 bytes, and `()` is inhabited.
// - `IntoBytes`: Since `()` has size 0, it contains no padding bytes.
// - `Unaligned`: `()` has alignment 1.
//
// [1] https://doc.rust-lang.org/1.81.0/reference/type-layout.html#tuple-layout
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl!((): Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
assert_unaligned!(());
};
// SAFETY:
// - `Immutable`: These types self-evidently do not contain any `UnsafeCell`s.
// - `TryFromBytes` (with no validator), `FromZeros`, `FromBytes`: all bit
// patterns are valid for numeric types [1]
// - `IntoBytes`: numeric types have no padding bytes [1]
// - `Unaligned` (`u8` and `i8` only): The reference [2] specifies the size of
// `u8` and `i8` as 1 byte. We also know that:
// - Alignment is >= 1 [3]
// - Size is an integer multiple of alignment [4]
// - The only value >= 1 for which 1 is an integer multiple is 1 Therefore,
// the only possible alignment for `u8` and `i8` is 1.
//
// [1] Per https://doc.rust-lang.org/1.81.0/reference/types/numeric.html#bit-validity:
//
// For every numeric type, `T`, the bit validity of `T` is equivalent to
// the bit validity of `[u8; size_of::<T>()]`. An uninitialized byte is
// not a valid `u8`.
//
// [2] https://doc.rust-lang.org/1.81.0/reference/type-layout.html#primitive-data-layout
//
// [3] Per https://doc.rust-lang.org/1.81.0/reference/type-layout.html#size-and-alignment:
//
// Alignment is measured in bytes, and must be at least 1.
//
// [4] Per https://doc.rust-lang.org/1.81.0/reference/type-layout.html#size-and-alignment:
//
// The size of a value is always a multiple of its alignment.
//
// FIXME(#278): Once we've updated the trait docs to refer to `u8`s rather than
// bits or bytes, update this comment, especially the reference to [1].
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl!(u8: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
unsafe_impl!(i8: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
assert_unaligned!(u8, i8);
unsafe_impl!(u16: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(i16: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(u32: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(i32: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(u64: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(i64: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(u128: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(i128: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(usize: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(isize: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(f32: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(f64: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
#[cfg(feature = "float-nightly")]
unsafe_impl!(#[cfg_attr(doc_cfg, doc(cfg(feature = "float-nightly")))] f16: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
#[cfg(feature = "float-nightly")]
unsafe_impl!(#[cfg_attr(doc_cfg, doc(cfg(feature = "float-nightly")))] f128: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes);
};
// SAFETY:
// - `Immutable`: `bool` self-evidently does not contain any `UnsafeCell`s.
// - `FromZeros`: Valid since "[t]he value false has the bit pattern 0x00" [1].
// - `IntoBytes`: Since "the boolean type has a size and alignment of 1 each"
// and "The value false has the bit pattern 0x00 and the value true has the
// bit pattern 0x01" [1]. Thus, the only byte of the bool is always
// initialized.
// - `Unaligned`: Per the reference [1], "[a]n object with the boolean type has
// a size and alignment of 1 each."
//
// [1] https://doc.rust-lang.org/1.81.0/reference/types/boolean.html
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe { unsafe_impl!(bool: Immutable, FromZeros, IntoBytes, Unaligned) };
assert_unaligned!(bool);
// SAFETY: The impl must only return `true` for its argument if the original
// `Maybe<bool>` refers to a valid `bool`. We only return true if the `u8` value
// is 0 or 1, and both of these are valid values for `bool` [1].
//
// [1] Per https://doc.rust-lang.org/1.81.0/reference/types/boolean.html:
//
// The value false has the bit pattern 0x00 and the value true has the bit
// pattern 0x01.
const _: () = unsafe {
unsafe_impl!(=> TryFromBytes for bool; |byte| {
let byte = byte.transmute_with::<u8, invariant::Valid, CastSizedExact, BecauseImmutable>();
*byte.unaligned_as_ref() < 2
})
};
// SAFETY:
// - `Immutable`: `char` self-evidently does not contain any `UnsafeCell`s.
// - `FromZeros`: Per reference [1], "[a] value of type char is a Unicode scalar
// value (i.e. a code point that is not a surrogate), represented as a 32-bit
// unsigned word in the 0x0000 to 0xD7FF or 0xE000 to 0x10FFFF range" which
// contains 0x0000.
// - `IntoBytes`: `char` is per reference [1] "represented as a 32-bit unsigned
// word" (`u32`) which is `IntoBytes`. Note that unlike `u32`, not all bit
// patterns are valid for `char`.
//
// [1] https://doc.rust-lang.org/1.81.0/reference/types/textual.html
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe { unsafe_impl!(char: Immutable, FromZeros, IntoBytes) };
// SAFETY: The impl must only return `true` for its argument if the original
// `Maybe<char>` refers to a valid `char`. `char::from_u32` guarantees that it
// returns `None` if its input is not a valid `char` [1].
//
// [1] Per https://doc.rust-lang.org/core/primitive.char.html#method.from_u32:
//
// `from_u32()` will return `None` if the input is not a valid value for a
// `char`.
const _: () = unsafe {
unsafe_impl!(=> TryFromBytes for char; |c| {
let c = c.transmute_with::<Unalign<u32>, invariant::Valid, CastSizedExact, BecauseImmutable>();
let c = c.read().into_inner();
char::from_u32(c).is_some()
});
};
// SAFETY: Per the Reference [1], `str` has the same layout as `[u8]`.
// - `Immutable`: `[u8]` does not contain any `UnsafeCell`s.
// - `FromZeros`, `IntoBytes`, `Unaligned`: `[u8]` is `FromZeros`, `IntoBytes`,
// and `Unaligned`.
//
// Note that we don't `assert_unaligned!(str)` because `assert_unaligned!` uses
// `align_of`, which only works for `Sized` types.
//
// FIXME(#429): Improve safety proof for `FromZeros` and `IntoBytes`; having the same
// layout as `[u8]` isn't sufficient.
//
// [1] Per https://doc.rust-lang.org/1.81.0/reference/type-layout.html#str-layout:
//
// String slices are a UTF-8 representation of characters that have the same
// layout as slices of type `[u8]`.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe { unsafe_impl!(str: Immutable, FromZeros, IntoBytes, Unaligned) };
// SAFETY: The impl must only return `true` for its argument if the original
// `Maybe<str>` refers to a valid `str`. `str::from_utf8` guarantees that it
// returns `Err` if its input is not a valid `str` [1].
//
// [1] Per https://doc.rust-lang.org/core/str/fn.from_utf8.html#errors:
//
// Returns `Err` if the slice is not UTF-8.
const _: () = unsafe {
unsafe_impl!(=> TryFromBytes for str; |c| {
let c = c.transmute_with::<[u8], invariant::Valid, CastUnsized, BecauseImmutable>();
let c = c.unaligned_as_ref();
core::str::from_utf8(c).is_ok()
})
};
macro_rules! unsafe_impl_try_from_bytes_for_nonzero {
($($nonzero:ident[$prim:ty]),*) => {
$(
unsafe_impl!(=> TryFromBytes for $nonzero; |n| {
let n = n.transmute_with::<Unalign<$prim>, invariant::Valid, CastSizedExact, BecauseImmutable>();
$nonzero::new(n.read().into_inner()).is_some()
});
)*
}
}
// `NonZeroXxx` is `IntoBytes`, but not `FromZeros` or `FromBytes`.
//
// SAFETY:
// - `IntoBytes`: `NonZeroXxx` has the same layout as its associated primitive.
// Since it is the same size, this guarantees it has no padding - integers
// have no padding, and there's no room for padding if it can represent all
// of the same values except 0.
// - `Unaligned`: `NonZeroU8` and `NonZeroI8` document that `Option<NonZeroU8>`
// and `Option<NonZeroI8>` both have size 1. [1] [2] This is worded in a way
// that makes it unclear whether it's meant as a guarantee, but given the
// purpose of those types, it's virtually unthinkable that that would ever
// change. `Option` cannot be smaller than its contained type, which implies
// that, and `NonZeroX8` are of size 1 or 0. `NonZeroX8` can represent
// multiple states, so they cannot be 0 bytes, which means that they must be 1
// byte. The only valid alignment for a 1-byte type is 1.
//
// FIXME(#429):
// - Add quotes from documentation.
// - Add safety comment for `Immutable`. How can we prove that `NonZeroXxx`
// doesn't contain any `UnsafeCell`s? It's obviously true, but it's not clear
// how we'd prove it short of adding text to the stdlib docs that says so
// explicitly, which likely wouldn't be accepted.
//
// [1] Per https://doc.rust-lang.org/1.81.0/std/num/type.NonZeroU8.html:
//
// `NonZeroU8` is guaranteed to have the same layout and bit validity as `u8` with
// the exception that 0 is not a valid instance.
//
// [2] Per https://doc.rust-lang.org/1.81.0/std/num/type.NonZeroI8.html:
//
// `NonZeroI8` is guaranteed to have the same layout and bit validity as `i8` with
// the exception that 0 is not a valid instance.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl!(NonZeroU8: Immutable, IntoBytes, Unaligned);
unsafe_impl!(NonZeroI8: Immutable, IntoBytes, Unaligned);
assert_unaligned!(NonZeroU8, NonZeroI8);
unsafe_impl!(NonZeroU16: Immutable, IntoBytes);
unsafe_impl!(NonZeroI16: Immutable, IntoBytes);
unsafe_impl!(NonZeroU32: Immutable, IntoBytes);
unsafe_impl!(NonZeroI32: Immutable, IntoBytes);
unsafe_impl!(NonZeroU64: Immutable, IntoBytes);
unsafe_impl!(NonZeroI64: Immutable, IntoBytes);
unsafe_impl!(NonZeroU128: Immutable, IntoBytes);
unsafe_impl!(NonZeroI128: Immutable, IntoBytes);
unsafe_impl!(NonZeroUsize: Immutable, IntoBytes);
unsafe_impl!(NonZeroIsize: Immutable, IntoBytes);
unsafe_impl_try_from_bytes_for_nonzero!(
NonZeroU8[u8],
NonZeroI8[i8],
NonZeroU16[u16],
NonZeroI16[i16],
NonZeroU32[u32],
NonZeroI32[i32],
NonZeroU64[u64],
NonZeroI64[i64],
NonZeroU128[u128],
NonZeroI128[i128],
NonZeroUsize[usize],
NonZeroIsize[isize]
);
};
// SAFETY:
// - `TryFromBytes` (with no validator), `FromZeros`, `FromBytes`, `IntoBytes`:
// The Rust compiler reuses `0` value to represent `None`, so
// `size_of::<Option<NonZeroXxx>>() == size_of::<xxx>()`; see `NonZeroXxx`
// documentation.
// - `Unaligned`: `NonZeroU8` and `NonZeroI8` document that `Option<NonZeroU8>`
// and `Option<NonZeroI8>` both have size 1. [1] [2] This is worded in a way
// that makes it unclear whether it's meant as a guarantee, but given the
// purpose of those types, it's virtually unthinkable that that would ever
// change. The only valid alignment for a 1-byte type is 1.
//
// [1] Per https://doc.rust-lang.org/1.81.0/std/num/type.NonZeroU8.html:
//
// `Option<NonZeroU8>` is guaranteed to be compatible with `u8`, including in FFI.
//
// Thanks to the null pointer optimization, `NonZeroU8` and `Option<NonZeroU8>`
// are guaranteed to have the same size and alignment:
//
// [2] Per https://doc.rust-lang.org/1.81.0/std/num/type.NonZeroI8.html:
//
// `Option<NonZeroI8>` is guaranteed to be compatible with `i8`, including in FFI.
//
// Thanks to the null pointer optimization, `NonZeroI8` and `Option<NonZeroI8>`
// are guaranteed to have the same size and alignment:
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl!(Option<NonZeroU8>: TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
unsafe_impl!(Option<NonZeroI8>: TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
assert_unaligned!(Option<NonZeroU8>, Option<NonZeroI8>);
unsafe_impl!(Option<NonZeroU16>: TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(Option<NonZeroI16>: TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(Option<NonZeroU32>: TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(Option<NonZeroI32>: TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(Option<NonZeroU64>: TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(Option<NonZeroI64>: TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(Option<NonZeroU128>: TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(Option<NonZeroI128>: TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(Option<NonZeroUsize>: TryFromBytes, FromZeros, FromBytes, IntoBytes);
unsafe_impl!(Option<NonZeroIsize>: TryFromBytes, FromZeros, FromBytes, IntoBytes);
};
// SAFETY: While it's not fully documented, the consensus is that `Box<T>` does
// not contain any `UnsafeCell`s for `T: Sized` [1]. This is not a complete
// proof, but we are accepting this as a known risk per #1358.
//
// [1] https://github.com/rust-lang/unsafe-code-guidelines/issues/492
#[cfg(feature = "alloc")]
const _: () = unsafe {
unsafe_impl!(
#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
T: Sized => Immutable for Box<T>
)
};
// SAFETY: The following types can be transmuted from `[0u8; size_of::<T>()]`. [1]
//
// [1] Per https://doc.rust-lang.org/1.89.0/core/option/index.html#representation:
//
// Rust guarantees to optimize the following types `T` such that [`Option<T>`]
// has the same size and alignment as `T`. In some of these cases, Rust
// further guarantees that `transmute::<_, Option<T>>([0u8; size_of::<T>()])`
// is sound and produces `Option::<T>::None`. These cases are identified by
// the second column:
//
// | `T` | `transmute::<_, Option<T>>([0u8; size_of::<T>()])` sound? |
// |-----------------------------------|-----------------------------------------------------------|
// | [`Box<U>`] | when `U: Sized` |
// | `&U` | when `U: Sized` |
// | `&mut U` | when `U: Sized` |
// | [`ptr::NonNull<U>`] | when `U: Sized` |
// | `fn`, `extern "C" fn`[^extern_fn] | always |
//
// [^extern_fn]: this remains true for `unsafe` variants, any argument/return
// types, and any other ABI: `[unsafe] extern "abi" fn` (_e.g._, `extern
// "system" fn`)
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
#[cfg(feature = "alloc")]
unsafe_impl!(
#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
T => TryFromBytes for Option<Box<T>>; |c| pointer::is_zeroed(c)
);
#[cfg(feature = "alloc")]
unsafe_impl!(
#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
T => FromZeros for Option<Box<T>>
);
unsafe_impl!(
T => TryFromBytes for Option<&'_ T>; |c| pointer::is_zeroed(c)
);
unsafe_impl!(T => FromZeros for Option<&'_ T>);
unsafe_impl!(
T => TryFromBytes for Option<&'_ mut T>; |c| pointer::is_zeroed(c)
);
unsafe_impl!(T => FromZeros for Option<&'_ mut T>);
unsafe_impl!(
T => TryFromBytes for Option<NonNull<T>>; |c| pointer::is_zeroed(c)
);
unsafe_impl!(T => FromZeros for Option<NonNull<T>>);
unsafe_impl_for_power_set!(A, B, C, D, E, F, G, H, I, J, K, L -> M => FromZeros for opt_fn!(...));
unsafe_impl_for_power_set!(
A, B, C, D, E, F, G, H, I, J, K, L -> M => TryFromBytes for opt_fn!(...);
|c| pointer::is_zeroed(c)
);
unsafe_impl_for_power_set!(A, B, C, D, E, F, G, H, I, J, K, L -> M => FromZeros for opt_unsafe_fn!(...));
unsafe_impl_for_power_set!(
A, B, C, D, E, F, G, H, I, J, K, L -> M => TryFromBytes for opt_unsafe_fn!(...);
|c| pointer::is_zeroed(c)
);
unsafe_impl_for_power_set!(A, B, C, D, E, F, G, H, I, J, K, L -> M => FromZeros for opt_extern_c_fn!(...));
unsafe_impl_for_power_set!(
A, B, C, D, E, F, G, H, I, J, K, L -> M => TryFromBytes for opt_extern_c_fn!(...);
|c| pointer::is_zeroed(c)
);
unsafe_impl_for_power_set!(A, B, C, D, E, F, G, H, I, J, K, L -> M => FromZeros for opt_unsafe_extern_c_fn!(...));
unsafe_impl_for_power_set!(
A, B, C, D, E, F, G, H, I, J, K, L -> M => TryFromBytes for opt_unsafe_extern_c_fn!(...);
|c| pointer::is_zeroed(c)
);
};
// SAFETY: `[unsafe] [extern "C"] fn()` self-evidently do not contain
// `UnsafeCell`s. This is not a proof, but we are accepting this as a known risk
// per #1358.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl_for_power_set!(A, B, C, D, E, F, G, H, I, J, K, L -> M => Immutable for opt_fn!(...));
unsafe_impl_for_power_set!(A, B, C, D, E, F, G, H, I, J, K, L -> M => Immutable for opt_unsafe_fn!(...));
unsafe_impl_for_power_set!(A, B, C, D, E, F, G, H, I, J, K, L -> M => Immutable for opt_extern_c_fn!(...));
unsafe_impl_for_power_set!(A, B, C, D, E, F, G, H, I, J, K, L -> M => Immutable for opt_unsafe_extern_c_fn!(...));
};
#[cfg(all(
not(no_zerocopy_target_has_atomics_1_60_0),
any(
target_has_atomic = "8",
target_has_atomic = "16",
target_has_atomic = "32",
target_has_atomic = "64",
target_has_atomic = "ptr"
)
))]
#[cfg_attr(doc_cfg, doc(cfg(rust = "1.60.0")))]
mod atomics {
use super::*;
macro_rules! impl_traits_for_atomics {
($($atomics:tt [$primitives:ty]),* $(,)?) => {
$(
impl_known_layout!($atomics);
impl_for_transmute_from!(=> FromZeros for $atomics [$primitives]);
impl_for_transmute_from!(=> FromBytes for $atomics [$primitives]);
impl_for_transmute_from!(=> TryFromBytes for $atomics [$primitives]);
impl_for_transmute_from!(=> IntoBytes for $atomics [$primitives]);
)*
};
}
/// Implements `TransmuteFrom` for `$atomic`, `$prim`, and
/// `UnsafeCell<$prim>`.
///
/// # Safety
///
/// `$atomic` must have the same size and bit validity as `$prim`.
macro_rules! unsafe_impl_transmute_from_for_atomic {
($($($tyvar:ident)? => $atomic:ty [$prim:ty]),*) => {{
crate::util::macros::__unsafe();
use crate::pointer::{SizeEq, TransmuteFrom, invariant::Valid};
$(
// SAFETY: The caller promised that `$atomic` and `$prim` have
// the same size and bit validity.
unsafe impl<$($tyvar)?> TransmuteFrom<$atomic, Valid, Valid> for $prim {}
// SAFETY: The caller promised that `$atomic` and `$prim` have
// the same size and bit validity.
unsafe impl<$($tyvar)?> TransmuteFrom<$prim, Valid, Valid> for $atomic {}
impl<$($tyvar)?> SizeEq<ReadOnly<$atomic>> for ReadOnly<$prim> {
type CastFrom = $crate::pointer::cast::CastSizedExact;
}
// SAFETY: The caller promised that `$atomic` and `$prim` have
// the same bit validity. `UnsafeCell<T>` has the same bit
// validity as `T` [1].
//
// [1] Per https://doc.rust-lang.org/1.85.0/std/cell/struct.UnsafeCell.html#memory-layout:
//
// `UnsafeCell<T>` has the same in-memory representation as
// its inner type `T`. A consequence of this guarantee is that
// it is possible to convert between `T` and `UnsafeCell<T>`.
unsafe impl<$($tyvar)?> TransmuteFrom<$atomic, Valid, Valid> for core::cell::UnsafeCell<$prim> {}
// SAFETY: See previous safety comment.
unsafe impl<$($tyvar)?> TransmuteFrom<core::cell::UnsafeCell<$prim>, Valid, Valid> for $atomic {}
)*
}};
}
#[cfg(target_has_atomic = "8")]
#[cfg_attr(doc_cfg, doc(cfg(target_has_atomic = "8")))]
mod atomic_8 {
use core::sync::atomic::{AtomicBool, AtomicI8, AtomicU8};
use super::*;
impl_traits_for_atomics!(AtomicU8[u8], AtomicI8[i8]);
impl_known_layout!(AtomicBool);
impl_for_transmute_from!(=> FromZeros for AtomicBool [bool]);
impl_for_transmute_from!(=> TryFromBytes for AtomicBool [bool]);
impl_for_transmute_from!(=> IntoBytes for AtomicBool [bool]);
// SAFETY: Per [1], `AtomicBool`, `AtomicU8`, and `AtomicI8` have the
// same size as `bool`, `u8`, and `i8` respectively. Since a type's
// alignment cannot be smaller than 1 [2], and since its alignment
// cannot be greater than its size [3], the only possible value for the
// alignment is 1. Thus, it is sound to implement `Unaligned`.
//
// [1] Per (for example) https://doc.rust-lang.org/1.81.0/std/sync/atomic/struct.AtomicU8.html:
//
// This type has the same size, alignment, and bit validity as the
// underlying integer type
//
// [2] Per https://doc.rust-lang.org/1.81.0/reference/type-layout.html#size-and-alignment:
//
// Alignment is measured in bytes, and must be at least 1.
//
// [3] Per https://doc.rust-lang.org/1.81.0/reference/type-layout.html#size-and-alignment:
//
// The size of a value is always a multiple of its alignment.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl!(AtomicBool: Unaligned);
unsafe_impl!(AtomicU8: Unaligned);
unsafe_impl!(AtomicI8: Unaligned);
assert_unaligned!(AtomicBool, AtomicU8, AtomicI8);
};
// SAFETY: `AtomicU8`, `AtomicI8`, and `AtomicBool` have the same size
// and bit validity as `u8`, `i8`, and `bool` respectively [1][2][3].
//
// [1] Per https://doc.rust-lang.org/1.85.0/std/sync/atomic/struct.AtomicU8.html:
//
// This type has the same size, alignment, and bit validity as the
// underlying integer type, `u8`.
//
// [2] Per https://doc.rust-lang.org/1.85.0/std/sync/atomic/struct.AtomicI8.html:
//
// This type has the same size, alignment, and bit validity as the
// underlying integer type, `i8`.
//
// [3] Per https://doc.rust-lang.org/1.85.0/std/sync/atomic/struct.AtomicBool.html:
//
// This type has the same size, alignment, and bit validity a `bool`.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl_transmute_from_for_atomic!(
=> AtomicU8 [u8],
=> AtomicI8 [i8],
=> AtomicBool [bool]
)
};
}
#[cfg(target_has_atomic = "16")]
#[cfg_attr(doc_cfg, doc(cfg(target_has_atomic = "16")))]
mod atomic_16 {
use core::sync::atomic::{AtomicI16, AtomicU16};
use super::*;
impl_traits_for_atomics!(AtomicU16[u16], AtomicI16[i16]);
// SAFETY: `AtomicU16` and `AtomicI16` have the same size and bit
// validity as `u16` and `i16` respectively [1][2].
//
// [1] Per https://doc.rust-lang.org/1.85.0/std/sync/atomic/struct.AtomicU16.html:
//
// This type has the same size and bit validity as the underlying
// integer type, `u16`.
//
// [2] Per https://doc.rust-lang.org/1.85.0/std/sync/atomic/struct.AtomicI16.html:
//
// This type has the same size and bit validity as the underlying
// integer type, `i16`.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl_transmute_from_for_atomic!(=> AtomicU16 [u16], => AtomicI16 [i16])
};
}
#[cfg(target_has_atomic = "32")]
#[cfg_attr(doc_cfg, doc(cfg(target_has_atomic = "32")))]
mod atomic_32 {
use core::sync::atomic::{AtomicI32, AtomicU32};
use super::*;
impl_traits_for_atomics!(AtomicU32[u32], AtomicI32[i32]);
// SAFETY: `AtomicU32` and `AtomicI32` have the same size and bit
// validity as `u32` and `i32` respectively [1][2].
//
// [1] Per https://doc.rust-lang.org/1.85.0/std/sync/atomic/struct.AtomicU32.html:
//
// This type has the same size and bit validity as the underlying
// integer type, `u32`.
//
// [2] Per https://doc.rust-lang.org/1.85.0/std/sync/atomic/struct.AtomicI32.html:
//
// This type has the same size and bit validity as the underlying
// integer type, `i32`.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl_transmute_from_for_atomic!(=> AtomicU32 [u32], => AtomicI32 [i32])
};
}
#[cfg(target_has_atomic = "64")]
#[cfg_attr(doc_cfg, doc(cfg(target_has_atomic = "64")))]
mod atomic_64 {
use core::sync::atomic::{AtomicI64, AtomicU64};
use super::*;
impl_traits_for_atomics!(AtomicU64[u64], AtomicI64[i64]);
// SAFETY: `AtomicU64` and `AtomicI64` have the same size and bit
// validity as `u64` and `i64` respectively [1][2].
//
// [1] Per https://doc.rust-lang.org/1.85.0/std/sync/atomic/struct.AtomicU64.html:
//
// This type has the same size and bit validity as the underlying
// integer type, `u64`.
//
// [2] Per https://doc.rust-lang.org/1.85.0/std/sync/atomic/struct.AtomicI64.html:
//
// This type has the same size and bit validity as the underlying
// integer type, `i64`.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl_transmute_from_for_atomic!(=> AtomicU64 [u64], => AtomicI64 [i64])
};
}
#[cfg(target_has_atomic = "ptr")]
#[cfg_attr(doc_cfg, doc(cfg(target_has_atomic = "ptr")))]
mod atomic_ptr {
use core::sync::atomic::{AtomicIsize, AtomicPtr, AtomicUsize};
use super::*;
impl_traits_for_atomics!(AtomicUsize[usize], AtomicIsize[isize]);
// FIXME(#170): Implement `FromBytes` and `IntoBytes` once we implement
// those traits for `*mut T`.
impl_known_layout!(T => AtomicPtr<T>);
impl_for_transmute_from!(T => TryFromBytes for AtomicPtr<T> [*mut T]);
impl_for_transmute_from!(T => FromZeros for AtomicPtr<T> [*mut T]);
// SAFETY: `AtomicUsize` and `AtomicIsize` have the same size and bit
// validity as `usize` and `isize` respectively [1][2].
//
// [1] Per https://doc.rust-lang.org/1.85.0/std/sync/atomic/struct.AtomicUsize.html:
//
// This type has the same size and bit validity as the underlying
// integer type, `usize`.
//
// [2] Per https://doc.rust-lang.org/1.85.0/std/sync/atomic/struct.AtomicIsize.html:
//
// This type has the same size and bit validity as the underlying
// integer type, `isize`.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl_transmute_from_for_atomic!(=> AtomicUsize [usize], => AtomicIsize [isize])
};
// SAFETY: Per
// https://doc.rust-lang.org/1.85.0/std/sync/atomic/struct.AtomicPtr.html:
//
// This type has the same size and bit validity as a `*mut T`.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe { unsafe_impl_transmute_from_for_atomic!(T => AtomicPtr<T> [*mut T]) };
}
}
// SAFETY: Per reference [1]: "For all T, the following are guaranteed:
// size_of::<PhantomData<T>>() == 0 align_of::<PhantomData<T>>() == 1". This
// gives:
// - `Immutable`: `PhantomData` has no fields.
// - `TryFromBytes` (with no validator), `FromZeros`, `FromBytes`: There is only
// one possible sequence of 0 bytes, and `PhantomData` is inhabited.
// - `IntoBytes`: Since `PhantomData` has size 0, it contains no padding bytes.
// - `Unaligned`: Per the preceding reference, `PhantomData` has alignment 1.
//
// [1] https://doc.rust-lang.org/1.81.0/std/marker/struct.PhantomData.html#layout-1
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl!(T: ?Sized => Immutable for PhantomData<T>);
unsafe_impl!(T: ?Sized => TryFromBytes for PhantomData<T>);
unsafe_impl!(T: ?Sized => FromZeros for PhantomData<T>);
unsafe_impl!(T: ?Sized => FromBytes for PhantomData<T>);
unsafe_impl!(T: ?Sized => IntoBytes for PhantomData<T>);
unsafe_impl!(T: ?Sized => Unaligned for PhantomData<T>);
assert_unaligned!(PhantomData<()>, PhantomData<u8>, PhantomData<u64>);
};
impl_for_transmute_from!(T: TryFromBytes => TryFromBytes for Wrapping<T>[T]);
impl_for_transmute_from!(T: FromZeros => FromZeros for Wrapping<T>[T]);
impl_for_transmute_from!(T: FromBytes => FromBytes for Wrapping<T>[T]);
impl_for_transmute_from!(T: IntoBytes => IntoBytes for Wrapping<T>[T]);
assert_unaligned!(Wrapping<()>, Wrapping<u8>);
// SAFETY: Per [1], `Wrapping<T>` has the same layout as `T`. Since its single
// field (of type `T`) is public, it would be a breaking change to add or remove
// fields. Thus, we know that `Wrapping<T>` contains a `T` (as opposed to just
// having the same size and alignment as `T`) with no pre- or post-padding.
// Thus, `Wrapping<T>` must have `UnsafeCell`s covering the same byte ranges as
// `Inner = T`.
//
// [1] Per https://doc.rust-lang.org/1.81.0/std/num/struct.Wrapping.html#layout-1:
//
// `Wrapping<T>` is guaranteed to have the same layout and ABI as `T`
const _: () = unsafe { unsafe_impl!(T: Immutable => Immutable for Wrapping<T>) };
// SAFETY: Per [1] in the preceding safety comment, `Wrapping<T>` has the same
// alignment as `T`.
const _: () = unsafe { unsafe_impl!(T: Unaligned => Unaligned for Wrapping<T>) };
// SAFETY: `TryFromBytes` (with no validator), `FromZeros`, `FromBytes`:
// `MaybeUninit<T>` has no restrictions on its contents.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl!(T => TryFromBytes for CoreMaybeUninit<T>);
unsafe_impl!(T => FromZeros for CoreMaybeUninit<T>);
unsafe_impl!(T => FromBytes for CoreMaybeUninit<T>);
};
// SAFETY: `MaybeUninit<T>` has `UnsafeCell`s covering the same byte ranges as
// `Inner = T`. This is not explicitly documented, but it can be inferred. Per
// [1], `MaybeUninit<T>` has the same size as `T`. Further, note the signature
// of `MaybeUninit::assume_init_ref` [2]:
//
// pub unsafe fn assume_init_ref(&self) -> &T
//
// If the argument `&MaybeUninit<T>` and the returned `&T` had `UnsafeCell`s at
// different offsets, this would be unsound. Its existence is proof that this is
// not the case.
//
// [1] Per https://doc.rust-lang.org/1.81.0/std/mem/union.MaybeUninit.html#layout-1:
//
// `MaybeUninit<T>` is guaranteed to have the same size, alignment, and ABI as
// `T`.
//
// [2] https://doc.rust-lang.org/1.81.0/std/mem/union.MaybeUninit.html#method.assume_init_ref
const _: () = unsafe { unsafe_impl!(T: Immutable => Immutable for CoreMaybeUninit<T>) };
// SAFETY: Per [1] in the preceding safety comment, `MaybeUninit<T>` has the
// same alignment as `T`.
const _: () = unsafe { unsafe_impl!(T: Unaligned => Unaligned for CoreMaybeUninit<T>) };
assert_unaligned!(CoreMaybeUninit<()>, CoreMaybeUninit<u8>);
// SAFETY: `ManuallyDrop<T>` has the same layout as `T` [1]. This strongly
// implies, but does not guarantee, that it contains `UnsafeCell`s covering the
// same byte ranges as in `T`. However, it also implements `Defer<Target = T>`
// [2], which provides the ability to convert `&ManuallyDrop<T> -> &T`. This,
// combined with having the same size as `T`, implies that `ManuallyDrop<T>`
// exactly contains a `T` with the same fields and `UnsafeCell`s covering the
// same byte ranges, or else the `Deref` impl would permit safe code to obtain
// different shared references to the same region of memory with different
// `UnsafeCell` coverage, which would in turn permit interior mutation that
// would violate the invariants of a shared reference.
//
// [1] Per https://doc.rust-lang.org/1.85.0/std/mem/struct.ManuallyDrop.html:
//
// `ManuallyDrop<T>` is guaranteed to have the same layout and bit validity as
// `T`
//
// [2] https://doc.rust-lang.org/1.85.0/std/mem/struct.ManuallyDrop.html#impl-Deref-for-ManuallyDrop%3CT%3E
const _: () = unsafe { unsafe_impl!(T: ?Sized + Immutable => Immutable for ManuallyDrop<T>) };
impl_for_transmute_from!(T: ?Sized + TryFromBytes => TryFromBytes for ManuallyDrop<T>[T]);
impl_for_transmute_from!(T: ?Sized + FromZeros => FromZeros for ManuallyDrop<T>[T]);
impl_for_transmute_from!(T: ?Sized + FromBytes => FromBytes for ManuallyDrop<T>[T]);
impl_for_transmute_from!(T: ?Sized + IntoBytes => IntoBytes for ManuallyDrop<T>[T]);
// SAFETY: `ManuallyDrop<T>` has the same layout as `T` [1], and thus has the
// same alignment as `T`.
//
// [1] Per https://doc.rust-lang.org/1.81.0/std/mem/struct.ManuallyDrop.html:
//
// `ManuallyDrop<T>` is guaranteed to have the same layout and bit validity as
// `T`
const _: () = unsafe { unsafe_impl!(T: ?Sized + Unaligned => Unaligned for ManuallyDrop<T>) };
assert_unaligned!(ManuallyDrop<()>, ManuallyDrop<u8>);
const _: () = {
#[allow(
non_camel_case_types,
missing_copy_implementations,
missing_debug_implementations,
missing_docs
)]
pub enum value {}
// SAFETY: See safety comment on `ProjectToTag`.
unsafe impl<T: ?Sized> HasTag for ManuallyDrop<T> {
#[inline]
fn only_derive_is_allowed_to_implement_this_trait()
where
Self: Sized,
{
}
type Tag = ();
// SAFETY: It is trivially sound to project any pointer to a pointer to
// a type of size zero and alignment 1 (which `()` is [1]). Such a
// pointer will trivially satisfy its aliasing and validity requirements
// (since it has a zero-sized referent), and its alignment requirement
// (since it is aligned to 1).
//
// [1] Per https://doc.rust-lang.org/1.92.0/reference/type-layout.html#r-layout.tuple.unit:
//
// [T]he unit tuple (`()`)... is guaranteed as a zero-sized type to
// have a size of 0 and an alignment of 1.
type ProjectToTag = crate::pointer::cast::CastToUnit;
}
// SAFETY: `ManuallyDrop<T>` has a field of type `T` at offset `0` without
// any safety invariants beyond those of `T`. Its existence is not
// explicitly documented, but it can be inferred; per [1] `ManuallyDrop<T>`
// has the same size and bit validity as `T`. This field is not literally
// public, but is effectively so; the field can be transparently:
//
// - initialized via `ManuallyDrop::new`
// - moved via `ManuallyDrop::into_inner`
// - referenced via `ManuallyDrop::deref`
// - exclusively referenced via `ManuallyDrop::deref_mut`
//
// We call this field `value`, both because that is both the name of this
// private field, and because it is the name it is referred to in the public
// documentation of `ManuallyDrop::new`, `ManuallyDrop::into_inner`,
// `ManuallyDrop::take` and `ManuallyDrop::drop`.
unsafe impl<T: ?Sized>
HasField<value, { crate::STRUCT_VARIANT_ID }, { crate::ident_id!(value) }>
for ManuallyDrop<T>
{
#[inline]
fn only_derive_is_allowed_to_implement_this_trait()
where
Self: Sized,
{
}
type Type = T;
#[inline(always)]
fn project(slf: PtrInner<'_, Self>) -> *mut T {
// SAFETY: `ManuallyDrop<T>` has the same layout and bit validity as
// `T` [1].
//
// [1] Per https://doc.rust-lang.org/1.85.0/std/mem/struct.ManuallyDrop.html:
//
// `ManuallyDrop<T>` is guaranteed to have the same layout and bit
// validity as `T`
#[allow(clippy::as_conversions)]
return slf.as_ptr() as *mut T;
}
}
};
impl_for_transmute_from!(T: ?Sized + TryFromBytes => TryFromBytes for Cell<T>[T]);
impl_for_transmute_from!(T: ?Sized + FromZeros => FromZeros for Cell<T>[T]);
impl_for_transmute_from!(T: ?Sized + FromBytes => FromBytes for Cell<T>[T]);
impl_for_transmute_from!(T: ?Sized + IntoBytes => IntoBytes for Cell<T>[T]);
// SAFETY: `Cell<T>` has the same in-memory representation as `T` [1], and thus
// has the same alignment as `T`.
//
// [1] Per https://doc.rust-lang.org/1.81.0/core/cell/struct.Cell.html#memory-layout:
//
// `Cell<T>` has the same in-memory representation as its inner type `T`.
const _: () = unsafe { unsafe_impl!(T: ?Sized + Unaligned => Unaligned for Cell<T>) };
impl_for_transmute_from!(T: ?Sized + FromZeros => FromZeros for UnsafeCell<T>[T]);
impl_for_transmute_from!(T: ?Sized + FromBytes => FromBytes for UnsafeCell<T>[T]);
impl_for_transmute_from!(T: ?Sized + IntoBytes => IntoBytes for UnsafeCell<T>[T]);
// SAFETY: `UnsafeCell<T>` has the same in-memory representation as `T` [1], and
// thus has the same alignment as `T`.
//
// [1] Per https://doc.rust-lang.org/1.81.0/core/cell/struct.UnsafeCell.html#memory-layout:
//
// `UnsafeCell<T>` has the same in-memory representation as its inner type
// `T`.
const _: () = unsafe { unsafe_impl!(T: ?Sized + Unaligned => Unaligned for UnsafeCell<T>) };
assert_unaligned!(UnsafeCell<()>, UnsafeCell<u8>);
// SAFETY: See safety comment in `is_bit_valid` impl.
unsafe impl<T: TryFromBytes + ?Sized> TryFromBytes for UnsafeCell<T> {
#[allow(clippy::missing_inline_in_public_items)]
fn only_derive_is_allowed_to_implement_this_trait()
where
Self: Sized,
{
}
#[inline(always)]
fn is_bit_valid<A>(candidate: Maybe<'_, Self, A>) -> bool
where
A: invariant::Alignment,
{
T::is_bit_valid(candidate.transmute::<_, _, BecauseImmutable>())
}
}
// SAFETY: Per the reference [1]:
//
// An array of `[T; N]` has a size of `size_of::<T>() * N` and the same
// alignment of `T`. Arrays are laid out so that the zero-based `nth` element
// of the array is offset from the start of the array by `n * size_of::<T>()`
// bytes.
//
// ...
//
// Slices have the same layout as the section of the array they slice.
//
// In other words, the layout of a `[T]` or `[T; N]` is a sequence of `T`s laid
// out back-to-back with no bytes in between. Therefore, `[T]` or `[T; N]` are
// `Immutable`, `TryFromBytes`, `FromZeros`, `FromBytes`, and `IntoBytes` if `T`
// is (respectively). Furthermore, since an array/slice has "the same alignment
// of `T`", `[T]` and `[T; N]` are `Unaligned` if `T` is.
//
// Note that we don't `assert_unaligned!` for slice types because
// `assert_unaligned!` uses `align_of`, which only works for `Sized` types.
//
// [1] https://doc.rust-lang.org/1.81.0/reference/type-layout.html#array-layout
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl!(const N: usize, T: Immutable => Immutable for [T; N]);
unsafe_impl!(const N: usize, T: TryFromBytes => TryFromBytes for [T; N]; |c| {
let c: Ptr<'_, [ReadOnly<T>; N], _> = c.cast::<_, crate::pointer::cast::CastSized, _>();
let c: Ptr<'_, [ReadOnly<T>], _> = c.as_slice();
let c: Ptr<'_, ReadOnly<[T]>, _> = c.cast::<_, crate::pointer::cast::CastUnsized, _>();
// Note that this call may panic, but it would still be sound even if it
// did. `is_bit_valid` does not promise that it will not panic (in fact,
// it explicitly warns that it's a possibility), and we have not
// violated any safety invariants that we must fix before returning.
<[T] as TryFromBytes>::is_bit_valid(c)
});
unsafe_impl!(const N: usize, T: FromZeros => FromZeros for [T; N]);
unsafe_impl!(const N: usize, T: FromBytes => FromBytes for [T; N]);
unsafe_impl!(const N: usize, T: IntoBytes => IntoBytes for [T; N]);
unsafe_impl!(const N: usize, T: Unaligned => Unaligned for [T; N]);
assert_unaligned!([(); 0], [(); 1], [u8; 0], [u8; 1]);
unsafe_impl!(T: Immutable => Immutable for [T]);
unsafe_impl!(T: TryFromBytes => TryFromBytes for [T]; |c| {
let c: Ptr<'_, [ReadOnly<T>], _> = c.cast::<_, crate::pointer::cast::CastUnsized, _>();
// SAFETY: Per the reference [1]:
//
// An array of `[T; N]` has a size of `size_of::<T>() * N` and the
// same alignment of `T`. Arrays are laid out so that the zero-based
// `nth` element of the array is offset from the start of the array by
// `n * size_of::<T>()` bytes.
//
// ...
//
// Slices have the same layout as the section of the array they slice.
//
// In other words, the layout of a `[T] is a sequence of `T`s laid out
// back-to-back with no bytes in between. If all elements in `candidate`
// are `is_bit_valid`, so too is `candidate`.
//
// Note that any of the below calls may panic, but it would still be
// sound even if it did. `is_bit_valid` does not promise that it will
// not panic (in fact, it explicitly warns that it's a possibility), and
// we have not violated any safety invariants that we must fix before
// returning.
c.iter().all(<T as TryFromBytes>::is_bit_valid)
});
unsafe_impl!(T: FromZeros => FromZeros for [T]);
unsafe_impl!(T: FromBytes => FromBytes for [T]);
unsafe_impl!(T: IntoBytes => IntoBytes for [T]);
unsafe_impl!(T: Unaligned => Unaligned for [T]);
};
// SAFETY:
// - `Immutable`: Raw pointers do not contain any `UnsafeCell`s.
// - `FromZeros`: For thin pointers (note that `T: Sized`), the zero pointer is
// considered "null". [1] No operations which require provenance are legal on
// null pointers, so this is not a footgun.
// - `TryFromBytes`: By the same reasoning as for `FromZeroes`, we can implement
// `TryFromBytes` for thin pointers provided that
// [`TryFromByte::is_bit_valid`] only produces `true` for zeroed bytes.
//
// NOTE(#170): Implementing `FromBytes` and `IntoBytes` for raw pointers would
// be sound, but carries provenance footguns. We want to support `FromBytes` and
// `IntoBytes` for raw pointers eventually, but we are holding off until we can
// figure out how to address those footguns.
//
// [1] Per https://doc.rust-lang.org/1.81.0/std/ptr/fn.null.html:
//
// Creates a null raw pointer.
//
// This function is equivalent to zero-initializing the pointer:
// `MaybeUninit::<*const T>::zeroed().assume_init()`.
//
// The resulting pointer has the address 0.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl!(T: ?Sized => Immutable for *const T);
unsafe_impl!(T: ?Sized => Immutable for *mut T);
unsafe_impl!(T => TryFromBytes for *const T; |c| pointer::is_zeroed(c));
unsafe_impl!(T => FromZeros for *const T);
unsafe_impl!(T => TryFromBytes for *mut T; |c| pointer::is_zeroed(c));
unsafe_impl!(T => FromZeros for *mut T);
};
// SAFETY: `NonNull<T>` self-evidently does not contain `UnsafeCell`s. This is
// not a proof, but we are accepting this as a known risk per #1358.
const _: () = unsafe { unsafe_impl!(T: ?Sized => Immutable for NonNull<T>) };
// SAFETY: Reference types do not contain any `UnsafeCell`s.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
unsafe_impl!(T: ?Sized => Immutable for &'_ T);
unsafe_impl!(T: ?Sized => Immutable for &'_ mut T);
};
// SAFETY: `Option` is not `#[non_exhaustive]` [1], which means that the types
// in its variants cannot change, and no new variants can be added. `Option<T>`
// does not contain any `UnsafeCell`s outside of `T`. [1]
//
// [1] https://doc.rust-lang.org/core/option/enum.Option.html
const _: () = unsafe { unsafe_impl!(T: Immutable => Immutable for Option<T>) };
mod tuples {
use super::*;
/// Generates various trait implementations for tuples.
///
/// # Safety
///
/// `impl_tuple!` should be provided name-number pairs, where each number is
/// the ordinal of the preceding type name.
macro_rules! impl_tuple {
// Entry point.
($($T:ident $I:tt),+ $(,)?) => {
crate::util::macros::__unsafe();
impl_tuple!(@all [] [$($T $I)+]);
};
// Build up the set of tuple types (i.e., `(A,)`, `(A, B)`, `(A, B, C)`,
// etc.) Trait implementations that do not depend on field index may be
// added to this branch.
(@all [$($head_T:ident $head_I:tt)*] [$next_T:ident $next_I:tt $($tail:tt)*]) => {
// SAFETY: If all fields of the tuple `Self` are `Immutable`, so too is `Self`.
unsafe_impl!($($head_T: Immutable,)* $next_T: Immutable => Immutable for ($($head_T,)* $next_T,));
// SAFETY: If all fields in `c` are `is_bit_valid`, so too is `c`.
unsafe_impl!($($head_T: TryFromBytes,)* $next_T: TryFromBytes => TryFromBytes for ($($head_T,)* $next_T,); |c| {
let mut c = c;
$(TryFromBytes::is_bit_valid(into_inner!(c.reborrow().project::<_, { crate::STRUCT_VARIANT_ID }, { crate::ident_id!($head_I) }>())) &&)*
TryFromBytes::is_bit_valid(into_inner!(c.reborrow().project::<_, { crate::STRUCT_VARIANT_ID }, { crate::ident_id!($next_I) }>()))
});
// SAFETY: If all fields in `Self` are `FromZeros`, so too is `Self`.
unsafe_impl!($($head_T: FromZeros,)* $next_T: FromZeros => FromZeros for ($($head_T,)* $next_T,));
// SAFETY: If all fields in `Self` are `FromBytes`, so too is `Self`.
unsafe_impl!($($head_T: FromBytes,)* $next_T: FromBytes => FromBytes for ($($head_T,)* $next_T,));
// SAFETY: See safety comment on `ProjectToTag`.
unsafe impl<$($head_T,)* $next_T> crate::HasTag for ($($head_T,)* $next_T,) {
#[inline]
fn only_derive_is_allowed_to_implement_this_trait()
where
Self: Sized
{}
type Tag = ();
// SAFETY: It is trivially sound to project any pointer to a
// pointer to a type of size zero and alignment 1 (which `()` is
// [1]). Such a pointer will trivially satisfy its aliasing and
// validity requirements (since it has a zero-sized referent),
// and its alignment requirement (since it is aligned to 1).
//
// [1] Per https://doc.rust-lang.org/1.92.0/reference/type-layout.html#r-layout.tuple.unit:
//
// [T]he unit tuple (`()`)... is guaranteed as a zero-sized
// type to have a size of 0 and an alignment of 1.
type ProjectToTag = crate::pointer::cast::CastToUnit;
}
// Generate impls that depend on tuple index.
impl_tuple!(@variants
[$($head_T $head_I)* $next_T $next_I]
[]
[$($head_T $head_I)* $next_T $next_I]
);
// Recurse to next tuple size
impl_tuple!(@all [$($head_T $head_I)* $next_T $next_I] [$($tail)*]);
};
(@all [$($head_T:ident $head_I:tt)*] []) => {};
// Emit trait implementations that depend on field index.
(@variants
// The full tuple definition in type–index pairs.
[$($AllT:ident $AllI:tt)+]
// Types before the current index.
[$($BeforeT:ident)*]
// The types and indices at and after the current index.
[$CurrT:ident $CurrI:tt $($AfterT:ident $AfterI:tt)*]
) => {
// SAFETY:
// - `Self` is a struct (albeit anonymous), so `VARIANT_ID` is
// `STRUCT_VARIANT_ID`.
// - `$CurrI` is the field at index `$CurrI`, so `FIELD_ID` is
// `zerocopy::ident_id!($CurrI)`
// - `()` has the same visibility as the `.$CurrI` field (ie, `.0`,
// `.1`, etc)
// - `Type` has the same type as `$CurrI`; i.e., `$CurrT`.
unsafe impl<$($AllT),+> crate::HasField<
(),
{ crate::STRUCT_VARIANT_ID },
{ crate::ident_id!($CurrI)}
> for ($($AllT,)+) {
#[inline]
fn only_derive_is_allowed_to_implement_this_trait()
where
Self: Sized
{}
type Type = $CurrT;
#[inline(always)]
fn project(slf: crate::PtrInner<'_, Self>) -> *mut Self::Type {
let slf = slf.as_non_null().as_ptr();
// SAFETY: `PtrInner` promises it references either a zero-sized
// byte range, or else will reference a byte range that is
// entirely contained within an allocated object. In either
// case, this guarantees that `(*slf).$CurrI` is in-bounds of
// `slf`.
unsafe { core::ptr::addr_of_mut!((*slf).$CurrI) }
}
}
// SAFETY: See comments on items.
unsafe impl<Aliasing, Alignment, $($AllT),+> crate::ProjectField<
(),
(Aliasing, Alignment, crate::invariant::Uninit),
{ crate::STRUCT_VARIANT_ID },
{ crate::ident_id!($CurrI)}
> for ($($AllT,)+)
where
Aliasing: crate::invariant::Aliasing,
Alignment: crate::invariant::Alignment,
{
#[inline]
fn only_derive_is_allowed_to_implement_this_trait()
where
Self: Sized
{}
// SAFETY: Tuples are product types whose fields are
// well-aligned, so projection preserves both the alignment and
// validity invariants of the outer pointer.
type Invariants = (Aliasing, Alignment, crate::invariant::Uninit);
// SAFETY: Tuples are product types and so projection is infallible;
type Error = core::convert::Infallible;
}
// SAFETY: See comments on items.
unsafe impl<Aliasing, Alignment, $($AllT),+> crate::ProjectField<
(),
(Aliasing, Alignment, crate::invariant::Initialized),
{ crate::STRUCT_VARIANT_ID },
{ crate::ident_id!($CurrI)}
> for ($($AllT,)+)
where
Aliasing: crate::invariant::Aliasing,
Alignment: crate::invariant::Alignment,
{
#[inline]
fn only_derive_is_allowed_to_implement_this_trait()
where
Self: Sized
{}
// SAFETY: Tuples are product types whose fields are
// well-aligned, so projection preserves both the alignment and
// validity invariants of the outer pointer.
type Invariants = (Aliasing, Alignment, crate::invariant::Initialized);
// SAFETY: Tuples are product types and so projection is infallible;
type Error = core::convert::Infallible;
}
// SAFETY: See comments on items.
unsafe impl<Aliasing, Alignment, $($AllT),+> crate::ProjectField<
(),
(Aliasing, Alignment, crate::invariant::Valid),
{ crate::STRUCT_VARIANT_ID },
{ crate::ident_id!($CurrI)}
> for ($($AllT,)+)
where
Aliasing: crate::invariant::Aliasing,
Alignment: crate::invariant::Alignment,
{
#[inline]
fn only_derive_is_allowed_to_implement_this_trait()
where
Self: Sized
{}
// SAFETY: Tuples are product types whose fields are
// well-aligned, so projection preserves both the alignment and
// validity invariants of the outer pointer.
type Invariants = (Aliasing, Alignment, crate::invariant::Valid);
// SAFETY: Tuples are product types and so projection is infallible;
type Error = core::convert::Infallible;
}
// Recurse to the next index.
impl_tuple!(@variants [$($AllT $AllI)+] [$($BeforeT)* $CurrT] [$($AfterT $AfterI)*]);
};
(@variants [$($AllT:ident $AllI:tt)+] [$($BeforeT:ident)*] []) => {};
}
// SAFETY: `impl_tuple` is provided name-number pairs, where number is the
// ordinal of the name.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
impl_tuple! {
A 0,
B 1,
C 2,
D 3,
E 4,
F 5,
G 6,
H 7,
I 8,
J 9,
K 10,
L 11,
M 12,
N 13,
O 14,
P 15,
Q 16,
R 17,
S 18,
T 19,
U 20,
V 21,
W 22,
X 23,
Y 24,
Z 25,
};
};
}
// SIMD support
//
// Per the Unsafe Code Guidelines Reference [1]:
//
// Packed SIMD vector types are `repr(simd)` homogeneous tuple-structs
// containing `N` elements of type `T` where `N` is a power-of-two and the
// size and alignment requirements of `T` are equal:
//
// ```rust
// #[repr(simd)]
// struct Vector<T, N>(T_0, ..., T_(N - 1));
// ```
//
// ...
//
// The size of `Vector` is `N * size_of::<T>()` and its alignment is an
// implementation-defined function of `T` and `N` greater than or equal to
// `align_of::<T>()`.
//
// ...
//
// Vector elements are laid out in source field order, enabling random access
// to vector elements by reinterpreting the vector as an array:
//
// ```rust
// union U {
// vec: Vector<T, N>,
// arr: [T; N]
// }
//
// assert_eq!(size_of::<Vector<T, N>>(), size_of::<[T; N]>());
// assert!(align_of::<Vector<T, N>>() >= align_of::<[T; N]>());
//
// unsafe {
// let u = U { vec: Vector<T, N>(t_0, ..., t_(N - 1)) };
//
// assert_eq!(u.vec.0, u.arr[0]);
// // ...
// assert_eq!(u.vec.(N - 1), u.arr[N - 1]);
// }
// ```
//
// Given this background, we can observe that:
// - The size and bit pattern requirements of a SIMD type are equivalent to the
// equivalent array type. Thus, for any SIMD type whose primitive `T` is
// `Immutable`, `TryFromBytes`, `FromZeros`, `FromBytes`, or `IntoBytes`, that
// SIMD type is also `Immutable`, `TryFromBytes`, `FromZeros`, `FromBytes`, or
// `IntoBytes` respectively.
// - Since no upper bound is placed on the alignment, no SIMD type can be
// guaranteed to be `Unaligned`.
//
// Also per [1]:
//
// This chapter represents the consensus from issue #38. The statements in
// here are not (yet) "guaranteed" not to change until an RFC ratifies them.
//
// See issue #38 [2]. While this behavior is not technically guaranteed, the
// likelihood that the behavior will change such that SIMD types are no longer
// `TryFromBytes`, `FromZeros`, `FromBytes`, or `IntoBytes` is next to zero, as
// that would defeat the entire purpose of SIMD types. Nonetheless, we put this
// behavior behind the `simd` Cargo feature, which requires consumers to opt
// into this stability hazard.
//
// [1] https://rust-lang.github.io/unsafe-code-guidelines/layout/packed-simd-vectors.html
// [2] https://github.com/rust-lang/unsafe-code-guidelines/issues/38
#[cfg(feature = "simd")]
#[cfg_attr(doc_cfg, doc(cfg(feature = "simd")))]
mod simd {
/// Defines a module which implements `TryFromBytes`, `FromZeros`,
/// `FromBytes`, and `IntoBytes` for a set of types from a module in
/// `core::arch`.
///
/// `$arch` is both the name of the defined module and the name of the
/// module in `core::arch`, and `$typ` is the list of items from that module
/// to implement `FromZeros`, `FromBytes`, and `IntoBytes` for.
#[allow(unused_macros)] // `allow(unused_macros)` is needed because some
// target/feature combinations don't emit any impls
// and thus don't use this macro.
macro_rules! simd_arch_mod {
($(#[cfg $cfg:tt])* $(#[cfg_attr $cfg_attr:tt])? $arch:ident, $mod:ident, $($typ:ident),*) => {
$(#[cfg $cfg])*
#[cfg_attr(doc_cfg, doc(cfg $($cfg)*))]
$(#[cfg_attr $cfg_attr])?
mod $mod {
use core::arch::$arch::{$($typ),*};
use crate::*;
impl_known_layout!($($typ),*);
// SAFETY: See comment on module definition for justification.
#[allow(clippy::multiple_unsafe_ops_per_block)]
const _: () = unsafe {
$( unsafe_impl!($typ: Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes); )*
};
}
};
}
#[rustfmt::skip]
const _: () = {
simd_arch_mod!(
#[cfg(target_arch = "x86")]
x86, x86, __m128, __m128d, __m128i, __m256, __m256d, __m256i
);
#[cfg(not(no_zerocopy_simd_x86_avx12_1_89_0))]
simd_arch_mod!(
#[cfg(target_arch = "x86")]
#[cfg_attr(doc_cfg, doc(cfg(rust = "1.89.0")))]
x86, x86_nightly, __m512bh, __m512, __m512d, __m512i
);
simd_arch_mod!(
#[cfg(target_arch = "x86_64")]
x86_64, x86_64, __m128, __m128d, __m128i, __m256, __m256d, __m256i
);
#[cfg(not(no_zerocopy_simd_x86_avx12_1_89_0))]
simd_arch_mod!(
#[cfg(target_arch = "x86_64")]
#[cfg_attr(doc_cfg, doc(cfg(rust = "1.89.0")))]
x86_64, x86_64_nightly, __m512bh, __m512, __m512d, __m512i
);
simd_arch_mod!(
#[cfg(target_arch = "wasm32")]
wasm32, wasm32, v128
);
simd_arch_mod!(
#[cfg(all(feature = "simd-nightly", target_arch = "powerpc"))]
powerpc, powerpc, vector_bool_long, vector_double, vector_signed_long, vector_unsigned_long
);
simd_arch_mod!(
#[cfg(all(feature = "simd-nightly", target_arch = "powerpc64"))]
powerpc64, powerpc64, vector_bool_long, vector_double, vector_signed_long, vector_unsigned_long
);
// NOTE: NEON intrinsics were broken on big-endian platforms from their stabilization up to
// Rust 1.87. (Context in https://github.com/rust-lang/stdarch/issues/1484). Support is
// split in two different version ranges on top of the base configuration, requiring either
// little endian or the more recent version to be detected as well.
#[cfg(not(no_zerocopy_aarch64_simd_1_59_0))]
simd_arch_mod!(
#[cfg(all(
target_arch = "aarch64",
any(
target_endian = "little",
not(no_zerocopy_aarch64_simd_be_1_87_0)
)
))]
#[cfg_attr(
doc_cfg,
doc(cfg(all(target_arch = "aarch64", any(
all(rust = "1.59.0", target_endian = "little"),
rust = "1.87.0",
))))
)]
aarch64, aarch64, float32x2_t, float32x4_t, float64x1_t, float64x2_t, int8x8_t, int8x8x2_t,
int8x8x3_t, int8x8x4_t, int8x16_t, int8x16x2_t, int8x16x3_t, int8x16x4_t, int16x4_t,
int16x8_t, int32x2_t, int32x4_t, int64x1_t, int64x2_t, poly8x8_t, poly8x8x2_t, poly8x8x3_t,
poly8x8x4_t, poly8x16_t, poly8x16x2_t, poly8x16x3_t, poly8x16x4_t, poly16x4_t, poly16x8_t,
poly64x1_t, poly64x2_t, uint8x8_t, uint8x8x2_t, uint8x8x3_t, uint8x8x4_t, uint8x16_t,
uint8x16x2_t, uint8x16x3_t, uint8x16x4_t, uint16x4_t, uint16x4x2_t, uint16x4x3_t,
uint16x4x4_t, uint16x8_t, uint32x2_t, uint32x4_t, uint64x1_t, uint64x2_t
);
};
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_impls() {
// A type that can supply test cases for testing
// `TryFromBytes::is_bit_valid`. All types passed to `assert_impls!`
// must implement this trait; that macro uses it to generate runtime
// tests for `TryFromBytes` impls.
//
// All `T: FromBytes` types are provided with a blanket impl. Other
// types must implement `TryFromBytesTestable` directly (ie using
// `impl_try_from_bytes_testable!`).
trait TryFromBytesTestable {
fn with_passing_test_cases<F: Fn(Box<ReadOnly<Self>>)>(f: F);
fn with_failing_test_cases<F: Fn(&mut [u8])>(f: F);
}
impl<T: FromBytes> TryFromBytesTestable for T {
fn with_passing_test_cases<F: Fn(Box<ReadOnly<Self>>)>(f: F) {
// Test with a zeroed value.
f(ReadOnly::<Self>::new_box_zeroed().unwrap());
let ffs = {
let mut t = ReadOnly::new(Self::new_zeroed());
let ptr: *mut T = ReadOnly::as_mut(&mut t);
// SAFETY: `T: FromBytes`
unsafe { ptr::write_bytes(ptr.cast::<u8>(), 0xFF, mem::size_of::<T>()) };
t
};
// Test with a value initialized with 0xFF.
f(Box::new(ffs));
}
fn with_failing_test_cases<F: Fn(&mut [u8])>(_f: F) {}
}
macro_rules! impl_try_from_bytes_testable_for_null_pointer_optimization {
($($tys:ty),*) => {
$(
impl TryFromBytesTestable for Option<$tys> {
fn with_passing_test_cases<F: Fn(Box<ReadOnly<Self>>)>(f: F) {
// Test with a zeroed value.
f(Box::new(ReadOnly::new(None)));
}
fn with_failing_test_cases<F: Fn(&mut [u8])>(f: F) {
for pos in 0..mem::size_of::<Self>() {
let mut bytes = [0u8; mem::size_of::<Self>()];
bytes[pos] = 0x01;
f(&mut bytes[..]);
}
}
}
)*
};
}
// Implements `TryFromBytesTestable`.
macro_rules! impl_try_from_bytes_testable {
// Base case for recursion (when the list of types has run out).
(=> @success $($success_case:expr),* $(, @failure $($failure_case:expr),*)?) => {};
// Implements for type(s) with no type parameters.
($ty:ty $(,$tys:ty)* => @success $($success_case:expr),* $(, @failure $($failure_case:expr),*)?) => {
impl TryFromBytesTestable for $ty {
impl_try_from_bytes_testable!(
@methods @success $($success_case),*
$(, @failure $($failure_case),*)?
);
}
impl_try_from_bytes_testable!($($tys),* => @success $($success_case),* $(, @failure $($failure_case),*)?);
};
// Implements for multiple types with no type parameters.
($($($ty:ty),* => @success $($success_case:expr), * $(, @failure $($failure_case:expr),*)?;)*) => {
$(
impl_try_from_bytes_testable!($($ty),* => @success $($success_case),* $(, @failure $($failure_case),*)*);
)*
};
// Implements only the methods; caller must invoke this from inside
// an impl block.
(@methods @success $($success_case:expr),* $(, @failure $($failure_case:expr),*)?) => {
fn with_passing_test_cases<F: Fn(Box<ReadOnly<Self>>)>(_f: F) {
$(
let bx = Box::<Self>::from($success_case);
let ro: Box<ReadOnly<_>> = {
let raw = Box::into_raw(bx);
// SAFETY: `ReadOnly<T>` has the same layout and bit
// validity as `T`.
#[allow(clippy::as_conversions)]
unsafe { Box::from_raw(raw as *mut _) }
};
_f(ro);
)*
}
fn with_failing_test_cases<F: Fn(&mut [u8])>(_f: F) {
$($(
let mut case = $failure_case;
_f(case.as_mut_bytes());
)*)?
}
};
}
impl_try_from_bytes_testable_for_null_pointer_optimization!(
Box<UnsafeCell<NotZerocopy>>,
&'static UnsafeCell<NotZerocopy>,
&'static mut UnsafeCell<NotZerocopy>,
NonNull<UnsafeCell<NotZerocopy>>,
fn(),
FnManyArgs,
extern "C" fn(),
ECFnManyArgs
);
macro_rules! bx {
($e:expr) => {
Box::new($e)
};
}
// Note that these impls are only for types which are not `FromBytes`.
// `FromBytes` types are covered by a preceding blanket impl.
impl_try_from_bytes_testable!(
bool => @success true, false,
@failure 2u8, 3u8, 0xFFu8;
char => @success '\u{0}', '\u{D7FF}', '\u{E000}', '\u{10FFFF}',
@failure 0xD800u32, 0xDFFFu32, 0x110000u32;
str => @success "", "hello", "❤️🧡💛💚💙💜",
@failure [0, 159, 146, 150];
[u8] => @success vec![].into_boxed_slice(), vec![0, 1, 2].into_boxed_slice();
NonZeroU8, NonZeroI8, NonZeroU16, NonZeroI16, NonZeroU32,
NonZeroI32, NonZeroU64, NonZeroI64, NonZeroU128, NonZeroI128,
NonZeroUsize, NonZeroIsize
=> @success Self::new(1).unwrap(),
// Doing this instead of `0` ensures that we always satisfy
// the size and alignment requirements of `Self` (whereas `0`
// may be any integer type with a different size or alignment
// than some `NonZeroXxx` types).
@failure Option::<Self>::None;
[bool; 0] => @success [];
[bool; 1]
=> @success [true], [false],
@failure [2u8], [3u8], [0xFFu8];
[bool]
=> @success vec![true, false].into_boxed_slice(), vec![false, true].into_boxed_slice(),
@failure [2u8], [3u8], [0xFFu8], [0u8, 1u8, 2u8];
Unalign<bool>
=> @success Unalign::new(false), Unalign::new(true),
@failure 2u8, 0xFFu8;
ManuallyDrop<bool>
=> @success ManuallyDrop::new(false), ManuallyDrop::new(true),
@failure 2u8, 0xFFu8;
ManuallyDrop<[u8]>
=> @success bx!(ManuallyDrop::new([])), bx!(ManuallyDrop::new([0u8])), bx!(ManuallyDrop::new([0u8, 1u8]));
ManuallyDrop<[bool]>
=> @success bx!(ManuallyDrop::new([])), bx!(ManuallyDrop::new([false])), bx!(ManuallyDrop::new([false, true])),
@failure [2u8], [3u8], [0xFFu8], [0u8, 1u8, 2u8];
ManuallyDrop<[UnsafeCell<u8>]>
=> @success bx!(ManuallyDrop::new([UnsafeCell::new(0)])), bx!(ManuallyDrop::new([UnsafeCell::new(0), UnsafeCell::new(1)]));
ManuallyDrop<[UnsafeCell<bool>]>
=> @success bx!(ManuallyDrop::new([UnsafeCell::new(false)])), bx!(ManuallyDrop::new([UnsafeCell::new(false), UnsafeCell::new(true)])),
@failure [2u8], [3u8], [0xFFu8], [0u8, 1u8, 2u8];
Wrapping<bool>
=> @success Wrapping(false), Wrapping(true),
@failure 2u8, 0xFFu8;
*const NotZerocopy
=> @success ptr::null::<NotZerocopy>(),
@failure [0x01; mem::size_of::<*const NotZerocopy>()];
*mut NotZerocopy
=> @success ptr::null_mut::<NotZerocopy>(),
@failure [0x01; mem::size_of::<*mut NotZerocopy>()];
);
// Use the trick described in [1] to allow us to call methods
// conditional on certain trait bounds.
//
// In all of these cases, methods return `Option<R>`, where `R` is the
// return type of the method we're conditionally calling. The "real"
// implementations (the ones defined in traits using `&self`) return
// `Some`, and the default implementations (the ones defined as inherent
// methods using `&mut self`) return `None`.
//
// [1] https://github.com/dtolnay/case-studies/blob/master/autoref-specialization/README.md
mod autoref_trick {
use super::*;
pub(super) struct AutorefWrapper<T: ?Sized>(pub(super) PhantomData<T>);
pub(super) trait TestIsBitValidShared<T: ?Sized> {
#[allow(clippy::needless_lifetimes)]
fn test_is_bit_valid_shared<'ptr>(&self, candidate: Maybe<'ptr, T>)
-> Option<bool>;
}
impl<T: TryFromBytes + Immutable + ?Sized> TestIsBitValidShared<T> for AutorefWrapper<T> {
#[allow(clippy::needless_lifetimes)]
fn test_is_bit_valid_shared<'ptr>(
&self,
candidate: Maybe<'ptr, T>,
) -> Option<bool> {
Some(T::is_bit_valid(candidate))
}
}
pub(super) trait TestTryFromRef<T: ?Sized> {
#[allow(clippy::needless_lifetimes)]
fn test_try_from_ref<'bytes>(
&self,
bytes: &'bytes [u8],
) -> Option<Option<&'bytes T>>;
}
impl<T: TryFromBytes + Immutable + KnownLayout + ?Sized> TestTryFromRef<T> for AutorefWrapper<T> {
#[allow(clippy::needless_lifetimes)]
fn test_try_from_ref<'bytes>(
&self,
bytes: &'bytes [u8],
) -> Option<Option<&'bytes T>> {
Some(T::try_ref_from_bytes(bytes).ok())
}
}
pub(super) trait TestTryFromMut<T: ?Sized> {
#[allow(clippy::needless_lifetimes)]
fn test_try_from_mut<'bytes>(
&self,
bytes: &'bytes mut [u8],
) -> Option<Option<&'bytes mut T>>;
}
impl<T: TryFromBytes + IntoBytes + KnownLayout + ?Sized> TestTryFromMut<T> for AutorefWrapper<T> {
#[allow(clippy::needless_lifetimes)]
fn test_try_from_mut<'bytes>(
&self,
bytes: &'bytes mut [u8],
) -> Option<Option<&'bytes mut T>> {
Some(T::try_mut_from_bytes(bytes).ok())
}
}
pub(super) trait TestTryReadFrom<T> {
fn test_try_read_from(&self, bytes: &[u8]) -> Option<Option<T>>;
}
impl<T: TryFromBytes> TestTryReadFrom<T> for AutorefWrapper<T> {
fn test_try_read_from(&self, bytes: &[u8]) -> Option<Option<T>> {
Some(T::try_read_from_bytes(bytes).ok())
}
}
pub(super) trait TestAsBytes<T: ?Sized> {
#[allow(clippy::needless_lifetimes)]
fn test_as_bytes<'slf, 't>(&'slf self, t: &'t ReadOnly<T>) -> Option<&'t [u8]>;
}
impl<T: IntoBytes + Immutable + ?Sized> TestAsBytes<T> for AutorefWrapper<T> {
#[allow(clippy::needless_lifetimes)]
fn test_as_bytes<'slf, 't>(&'slf self, t: &'t ReadOnly<T>) -> Option<&'t [u8]> {
Some(t.as_bytes())
}
}
}
use autoref_trick::*;
// Asserts that `$ty` is one of a list of types which are allowed to not
// provide a "real" implementation for `$fn_name`. Since the
// `autoref_trick` machinery fails silently, this allows us to ensure
// that the "default" impls are only being used for types which we
// expect.
//
// Note that, since this is a runtime test, it is possible to have an
// allowlist which is too restrictive if the function in question is
// never called for a particular type. For example, if `as_bytes` is not
// supported for a particular type, and so `test_as_bytes` returns
// `None`, methods such as `test_try_from_ref` may never be called for
// that type. As a result, it's possible that, for example, adding
// `as_bytes` support for a type would cause other allowlist assertions
// to fail. This means that allowlist assertion failures should not
// automatically be taken as a sign of a bug.
macro_rules! assert_on_allowlist {
($fn_name:ident($ty:ty) $(: $($tys:ty),*)?) => {{
use core::any::TypeId;
let allowlist: &[TypeId] = &[ $($(TypeId::of::<$tys>()),*)? ];
let allowlist_names: &[&str] = &[ $($(stringify!($tys)),*)? ];
let id = TypeId::of::<$ty>();
assert!(allowlist.contains(&id), "{} is not on allowlist for {}: {:?}", stringify!($ty), stringify!($fn_name), allowlist_names);
}};
}
// Asserts that `$ty` implements any `$trait` and doesn't implement any
// `!$trait`. Note that all `$trait`s must come before any `!$trait`s.
//
// For `T: TryFromBytes`, uses `TryFromBytesTestable` to test success
// and failure cases.
macro_rules! assert_impls {
($ty:ty: TryFromBytes) => {
// "Default" implementations that match the "real"
// implementations defined in the `autoref_trick` module above.
#[allow(unused, non_local_definitions)]
impl AutorefWrapper<$ty> {
#[allow(clippy::needless_lifetimes)]
fn test_is_bit_valid_shared<'ptr>(
&mut self,
candidate: Maybe<'ptr, $ty>,
) -> Option<bool> {
assert_on_allowlist!(
test_is_bit_valid_shared($ty):
ManuallyDrop<UnsafeCell<()>>,
ManuallyDrop<[UnsafeCell<u8>]>,
ManuallyDrop<[UnsafeCell<bool>]>,
CoreMaybeUninit<NotZerocopy>,
CoreMaybeUninit<UnsafeCell<()>>,
Wrapping<UnsafeCell<()>>
);
None
}
#[allow(clippy::needless_lifetimes)]
fn test_try_from_ref<'bytes>(&mut self, _bytes: &'bytes [u8]) -> Option<Option<&'bytes $ty>> {
assert_on_allowlist!(
test_try_from_ref($ty):
ManuallyDrop<[UnsafeCell<bool>]>
);
None
}
#[allow(clippy::needless_lifetimes)]
fn test_try_from_mut<'bytes>(&mut self, _bytes: &'bytes mut [u8]) -> Option<Option<&'bytes mut $ty>> {
assert_on_allowlist!(
test_try_from_mut($ty):
Option<Box<UnsafeCell<NotZerocopy>>>,
Option<&'static UnsafeCell<NotZerocopy>>,
Option<&'static mut UnsafeCell<NotZerocopy>>,
Option<NonNull<UnsafeCell<NotZerocopy>>>,
Option<fn()>,
Option<FnManyArgs>,
Option<extern "C" fn()>,
Option<ECFnManyArgs>,
*const NotZerocopy,
*mut NotZerocopy
);
None
}
fn test_try_read_from(&mut self, _bytes: &[u8]) -> Option<Option<&$ty>> {
assert_on_allowlist!(
test_try_read_from($ty):
str,
ManuallyDrop<[u8]>,
ManuallyDrop<[bool]>,
ManuallyDrop<[UnsafeCell<bool>]>,
[u8],
[bool]
);
None
}
fn test_as_bytes(&mut self, _t: &ReadOnly<$ty>) -> Option<&[u8]> {
assert_on_allowlist!(
test_as_bytes($ty):
Option<&'static UnsafeCell<NotZerocopy>>,
Option<&'static mut UnsafeCell<NotZerocopy>>,
Option<NonNull<UnsafeCell<NotZerocopy>>>,
Option<Box<UnsafeCell<NotZerocopy>>>,
Option<fn()>,
Option<FnManyArgs>,
Option<extern "C" fn()>,
Option<ECFnManyArgs>,
CoreMaybeUninit<u8>,
CoreMaybeUninit<NotZerocopy>,
CoreMaybeUninit<UnsafeCell<()>>,
ManuallyDrop<UnsafeCell<()>>,
ManuallyDrop<[UnsafeCell<u8>]>,
ManuallyDrop<[UnsafeCell<bool>]>,
Wrapping<UnsafeCell<()>>,
*const NotZerocopy,
*mut NotZerocopy
);
None
}
}
<$ty as TryFromBytesTestable>::with_passing_test_cases(|mut val| {
// FIXME(#494): These tests only get exercised for types
// which are `IntoBytes`. Once we implement #494, we should
// be able to support non-`IntoBytes` types by zeroing
// padding.
// We define `w` and `ww` since, in the case of the inherent
// methods, Rust thinks they're both borrowed mutably at the
// same time (given how we use them below). If we just
// defined a single `w` and used it for multiple operations,
// this would conflict.
//
// We `#[allow(unused_mut]` for the cases where the "real"
// impls are used, which take `&self`.
#[allow(unused_mut)]
let (mut w, mut ww) = (AutorefWrapper::<$ty>(PhantomData), AutorefWrapper::<$ty>(PhantomData));
let c = Ptr::from_ref(&*val);
let c = c.forget_aligned();
// SAFETY: FIXME(#899): This is unsound. `$ty` is not
// necessarily `IntoBytes`, but that's the corner we've
// backed ourselves into by using `Ptr::from_ref`.
let c = unsafe { c.assume_initialized() };
let res = w.test_is_bit_valid_shared(c);
if let Some(res) = res {
assert!(res, "{}::is_bit_valid (shared `Ptr`): got false, expected true", stringify!($ty));
}
let c = Ptr::from_mut(&mut *val);
let c = c.forget_aligned();
// SAFETY: FIXME(#899): This is unsound. `$ty` is not
// necessarily `IntoBytes`, but that's the corner we've
// backed ourselves into by using `Ptr::from_ref`.
let mut c = unsafe { c.assume_initialized() };
let res = <$ty as TryFromBytes>::is_bit_valid(c.reborrow_shared());
assert!(res, "{}::is_bit_valid (exclusive `Ptr`): got false, expected true", stringify!($ty));
// `bytes` is `Some(val.as_bytes())` if `$ty: IntoBytes +
// Immutable` and `None` otherwise.
let bytes = w.test_as_bytes(&*val);
// The inner closure returns
// `Some($ty::try_ref_from_bytes(bytes))` if `$ty:
// Immutable` and `None` otherwise.
let res = bytes.and_then(|bytes| ww.test_try_from_ref(bytes));
if let Some(res) = res {
assert!(res.is_some(), "{}::try_ref_from_bytes: got `None`, expected `Some`", stringify!($ty));
}
if let Some(bytes) = bytes {
// We need to get a mutable byte slice, and so we clone
// into a `Vec`. However, we also need these bytes to
// satisfy `$ty`'s alignment requirement, which isn't
// guaranteed for `Vec<u8>`. In order to get around
// this, we create a `Vec` which is twice as long as we
// need. There is guaranteed to be an aligned byte range
// of size `size_of_val(val)` within that range.
let val = &*val;
let size = mem::size_of_val(val);
let align = mem::align_of_val(val);
let mut vec = bytes.to_vec();
vec.extend(bytes);
let slc = vec.as_slice();
let offset = slc.as_ptr().align_offset(align);
let bytes_mut = &mut vec.as_mut_slice()[offset..offset+size];
bytes_mut.copy_from_slice(bytes);
let res = ww.test_try_from_mut(bytes_mut);
if let Some(res) = res {
assert!(res.is_some(), "{}::try_mut_from_bytes: got `None`, expected `Some`", stringify!($ty));
}
}
let res = bytes.and_then(|bytes| ww.test_try_read_from(bytes));
if let Some(res) = res {
assert!(res.is_some(), "{}::try_read_from_bytes: got `None`, expected `Some`", stringify!($ty));
}
});
#[allow(clippy::as_conversions)]
<$ty as TryFromBytesTestable>::with_failing_test_cases(|c| {
#[allow(unused_mut)] // For cases where the "real" impls are used, which take `&self`.
let mut w = AutorefWrapper::<$ty>(PhantomData);
// This is `Some($ty::try_ref_from_bytes(c))` if `$ty:
// Immutable` and `None` otherwise.
let res = w.test_try_from_ref(c);
if let Some(res) = res {
assert!(res.is_none(), "{}::try_ref_from_bytes({:?}): got Some, expected None", stringify!($ty), c);
}
let res = w.test_try_from_mut(c);
if let Some(res) = res {
assert!(res.is_none(), "{}::try_mut_from_bytes({:?}): got Some, expected None", stringify!($ty), c);
}
let res = w.test_try_read_from(c);
if let Some(res) = res {
assert!(res.is_none(), "{}::try_read_from_bytes({:?}): got Some, expected None", stringify!($ty), c);
}
});
#[allow(dead_code)]
const _: () = { static_assertions::assert_impl_all!($ty: TryFromBytes); };
};
($ty:ty: $trait:ident) => {
#[allow(dead_code)]
const _: () = { static_assertions::assert_impl_all!($ty: $trait); };
};
($ty:ty: !$trait:ident) => {
#[allow(dead_code)]
const _: () = { static_assertions::assert_not_impl_any!($ty: $trait); };
};
($ty:ty: $($trait:ident),* $(,)? $(!$negative_trait:ident),*) => {
$(
assert_impls!($ty: $trait);
)*
$(
assert_impls!($ty: !$negative_trait);
)*
};
}
// NOTE: The negative impl assertions here are not necessarily
// prescriptive. They merely serve as change detectors to make sure
// we're aware of what trait impls are getting added with a given
// change. Of course, some impls would be invalid (e.g., `bool:
// FromBytes`), and so this change detection is very important.
assert_impls!(
(): KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
Unaligned
);
assert_impls!(
u8: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
Unaligned
);
assert_impls!(
i8: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
Unaligned
);
assert_impls!(
u16: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
assert_impls!(
i16: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
assert_impls!(
u32: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
assert_impls!(
i32: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
assert_impls!(
u64: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
assert_impls!(
i64: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
assert_impls!(
u128: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
assert_impls!(
i128: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
assert_impls!(
usize: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
assert_impls!(
isize: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
#[cfg(feature = "float-nightly")]
assert_impls!(
f16: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
assert_impls!(
f32: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
assert_impls!(
f64: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
#[cfg(feature = "float-nightly")]
assert_impls!(
f128: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
!Unaligned
);
assert_impls!(
bool: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
IntoBytes,
Unaligned,
!FromBytes
);
assert_impls!(
char: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
IntoBytes,
!FromBytes,
!Unaligned
);
assert_impls!(
str: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
IntoBytes,
Unaligned,
!FromBytes
);
assert_impls!(
NonZeroU8: KnownLayout,
Immutable,
TryFromBytes,
IntoBytes,
Unaligned,
!FromZeros,
!FromBytes
);
assert_impls!(
NonZeroI8: KnownLayout,
Immutable,
TryFromBytes,
IntoBytes,
Unaligned,
!FromZeros,
!FromBytes
);
assert_impls!(
NonZeroU16: KnownLayout,
Immutable,
TryFromBytes,
IntoBytes,
!FromBytes,
!Unaligned
);
assert_impls!(
NonZeroI16: KnownLayout,
Immutable,
TryFromBytes,
IntoBytes,
!FromBytes,
!Unaligned
);
assert_impls!(
NonZeroU32: KnownLayout,
Immutable,
TryFromBytes,
IntoBytes,
!FromBytes,
!Unaligned
);
assert_impls!(
NonZeroI32: KnownLayout,
Immutable,
TryFromBytes,
IntoBytes,
!FromBytes,
!Unaligned
);
assert_impls!(
NonZeroU64: KnownLayout,
Immutable,
TryFromBytes,
IntoBytes,
!FromBytes,
!Unaligned
);
assert_impls!(
NonZeroI64: KnownLayout,
Immutable,
TryFromBytes,
IntoBytes,
!FromBytes,
!Unaligned
);
assert_impls!(
NonZeroU128: KnownLayout,
Immutable,
TryFromBytes,
IntoBytes,
!FromBytes,
!Unaligned
);
assert_impls!(
NonZeroI128: KnownLayout,
Immutable,
TryFromBytes,
IntoBytes,
!FromBytes,
!Unaligned
);
assert_impls!(
NonZeroUsize: KnownLayout,
Immutable,
TryFromBytes,
IntoBytes,
!FromBytes,
!Unaligned
);
assert_impls!(
NonZeroIsize: KnownLayout,
Immutable,
TryFromBytes,
IntoBytes,
!FromBytes,
!Unaligned
);
assert_impls!(Option<NonZeroU8>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
assert_impls!(Option<NonZeroI8>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
assert_impls!(Option<NonZeroU16>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, !Unaligned);
assert_impls!(Option<NonZeroI16>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, !Unaligned);
assert_impls!(Option<NonZeroU32>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, !Unaligned);
assert_impls!(Option<NonZeroI32>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, !Unaligned);
assert_impls!(Option<NonZeroU64>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, !Unaligned);
assert_impls!(Option<NonZeroI64>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, !Unaligned);
assert_impls!(Option<NonZeroU128>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, !Unaligned);
assert_impls!(Option<NonZeroI128>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, !Unaligned);
assert_impls!(Option<NonZeroUsize>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, !Unaligned);
assert_impls!(Option<NonZeroIsize>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, !Unaligned);
// Implements none of the ZC traits.
struct NotZerocopy;
#[rustfmt::skip]
type FnManyArgs = fn(
NotZerocopy, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8,
) -> (NotZerocopy, NotZerocopy);
// Allowed, because we're not actually using this type for FFI.
#[allow(improper_ctypes_definitions)]
#[rustfmt::skip]
type ECFnManyArgs = extern "C" fn(
NotZerocopy, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8,
) -> (NotZerocopy, NotZerocopy);
#[cfg(feature = "alloc")]
assert_impls!(Option<Box<UnsafeCell<NotZerocopy>>>: KnownLayout, Immutable, TryFromBytes, FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(Option<Box<[UnsafeCell<NotZerocopy>]>>: KnownLayout, !Immutable, !TryFromBytes, !FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(Option<&'static UnsafeCell<NotZerocopy>>: KnownLayout, Immutable, TryFromBytes, FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(Option<&'static [UnsafeCell<NotZerocopy>]>: KnownLayout, Immutable, !TryFromBytes, !FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(Option<&'static mut UnsafeCell<NotZerocopy>>: KnownLayout, Immutable, TryFromBytes, FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(Option<&'static mut [UnsafeCell<NotZerocopy>]>: KnownLayout, Immutable, !TryFromBytes, !FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(Option<NonNull<UnsafeCell<NotZerocopy>>>: KnownLayout, TryFromBytes, FromZeros, Immutable, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(Option<NonNull<[UnsafeCell<NotZerocopy>]>>: KnownLayout, Immutable, !TryFromBytes, !FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(Option<fn()>: KnownLayout, Immutable, TryFromBytes, FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(Option<FnManyArgs>: KnownLayout, Immutable, TryFromBytes, FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(Option<extern "C" fn()>: KnownLayout, Immutable, TryFromBytes, FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(Option<ECFnManyArgs>: KnownLayout, Immutable, TryFromBytes, FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(PhantomData<NotZerocopy>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
assert_impls!(PhantomData<UnsafeCell<()>>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
assert_impls!(PhantomData<[u8]>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
assert_impls!(ManuallyDrop<u8>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
// This test is important because it allows us to test our hand-rolled
// implementation of `<ManuallyDrop<T> as TryFromBytes>::is_bit_valid`.
assert_impls!(ManuallyDrop<bool>: KnownLayout, Immutable, TryFromBytes, FromZeros, IntoBytes, Unaligned, !FromBytes);
assert_impls!(ManuallyDrop<[u8]>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
// This test is important because it allows us to test our hand-rolled
// implementation of `<ManuallyDrop<T> as TryFromBytes>::is_bit_valid`.
assert_impls!(ManuallyDrop<[bool]>: KnownLayout, Immutable, TryFromBytes, FromZeros, IntoBytes, Unaligned, !FromBytes);
assert_impls!(ManuallyDrop<NotZerocopy>: !Immutable, !TryFromBytes, !KnownLayout, !FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(ManuallyDrop<[NotZerocopy]>: KnownLayout, !Immutable, !TryFromBytes, !FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(ManuallyDrop<UnsafeCell<()>>: KnownLayout, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned, !Immutable);
assert_impls!(ManuallyDrop<[UnsafeCell<u8>]>: KnownLayout, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned, !Immutable);
assert_impls!(ManuallyDrop<[UnsafeCell<bool>]>: KnownLayout, TryFromBytes, FromZeros, IntoBytes, Unaligned, !Immutable, !FromBytes);
assert_impls!(CoreMaybeUninit<u8>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, Unaligned, !IntoBytes);
assert_impls!(CoreMaybeUninit<NotZerocopy>: KnownLayout, TryFromBytes, FromZeros, FromBytes, !Immutable, !IntoBytes, !Unaligned);
assert_impls!(CoreMaybeUninit<UnsafeCell<()>>: KnownLayout, TryFromBytes, FromZeros, FromBytes, Unaligned, !Immutable, !IntoBytes);
assert_impls!(Wrapping<u8>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
// This test is important because it allows us to test our hand-rolled
// implementation of `<Wrapping<T> as TryFromBytes>::is_bit_valid`.
assert_impls!(Wrapping<bool>: KnownLayout, Immutable, TryFromBytes, FromZeros, IntoBytes, Unaligned, !FromBytes);
assert_impls!(Wrapping<NotZerocopy>: KnownLayout, !Immutable, !TryFromBytes, !FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(Wrapping<UnsafeCell<()>>: KnownLayout, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned, !Immutable);
assert_impls!(Unalign<u8>: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, Unaligned);
// This test is important because it allows us to test our hand-rolled
// implementation of `<Unalign<T> as TryFromBytes>::is_bit_valid`.
assert_impls!(Unalign<bool>: KnownLayout, Immutable, TryFromBytes, FromZeros, IntoBytes, Unaligned, !FromBytes);
assert_impls!(Unalign<NotZerocopy>: KnownLayout, Unaligned, !Immutable, !TryFromBytes, !FromZeros, !FromBytes, !IntoBytes);
assert_impls!(
[u8]: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
Unaligned
);
assert_impls!(
[bool]: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
IntoBytes,
Unaligned,
!FromBytes
);
assert_impls!([NotZerocopy]: KnownLayout, !Immutable, !TryFromBytes, !FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(
[u8; 0]: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
Unaligned,
);
assert_impls!(
[NotZerocopy; 0]: KnownLayout,
!Immutable,
!TryFromBytes,
!FromZeros,
!FromBytes,
!IntoBytes,
!Unaligned
);
assert_impls!(
[u8; 1]: KnownLayout,
Immutable,
TryFromBytes,
FromZeros,
FromBytes,
IntoBytes,
Unaligned,
);
assert_impls!(
[NotZerocopy; 1]: KnownLayout,
!Immutable,
!TryFromBytes,
!FromZeros,
!FromBytes,
!IntoBytes,
!Unaligned
);
assert_impls!(*const NotZerocopy: KnownLayout, Immutable, TryFromBytes, FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(*mut NotZerocopy: KnownLayout, Immutable, TryFromBytes, FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(*const [NotZerocopy]: KnownLayout, Immutable, !TryFromBytes, !FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(*mut [NotZerocopy]: KnownLayout, Immutable, !TryFromBytes, !FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(*const dyn Debug: KnownLayout, Immutable, !TryFromBytes, !FromZeros, !FromBytes, !IntoBytes, !Unaligned);
assert_impls!(*mut dyn Debug: KnownLayout, Immutable, !TryFromBytes, !FromZeros, !FromBytes, !IntoBytes, !Unaligned);
#[cfg(feature = "simd")]
{
#[allow(unused_macros)]
macro_rules! test_simd_arch_mod {
($arch:ident, $($typ:ident),*) => {
{
use core::arch::$arch::{$($typ),*};
use crate::*;
$( assert_impls!($typ: KnownLayout, Immutable, TryFromBytes, FromZeros, FromBytes, IntoBytes, !Unaligned); )*
}
};
}
#[cfg(target_arch = "x86")]
test_simd_arch_mod!(x86, __m128, __m128d, __m128i, __m256, __m256d, __m256i);
#[cfg(all(not(no_zerocopy_simd_x86_avx12_1_89_0), target_arch = "x86"))]
test_simd_arch_mod!(x86, __m512bh, __m512, __m512d, __m512i);
#[cfg(target_arch = "x86_64")]
test_simd_arch_mod!(x86_64, __m128, __m128d, __m128i, __m256, __m256d, __m256i);
#[cfg(all(not(no_zerocopy_simd_x86_avx12_1_89_0), target_arch = "x86_64"))]
test_simd_arch_mod!(x86_64, __m512bh, __m512, __m512d, __m512i);
#[cfg(target_arch = "wasm32")]
test_simd_arch_mod!(wasm32, v128);
#[cfg(all(feature = "simd-nightly", target_arch = "powerpc"))]
test_simd_arch_mod!(
powerpc,
vector_bool_long,
vector_double,
vector_signed_long,
vector_unsigned_long
);
#[cfg(all(feature = "simd-nightly", target_arch = "powerpc64"))]
test_simd_arch_mod!(
powerpc64,
vector_bool_long,
vector_double,
vector_signed_long,
vector_unsigned_long
);
#[cfg(all(target_arch = "aarch64", not(no_zerocopy_aarch64_simd_1_59_0)))]
#[rustfmt::skip]
test_simd_arch_mod!(
aarch64, float32x2_t, float32x4_t, float64x1_t, float64x2_t, int8x8_t, int8x8x2_t,
int8x8x3_t, int8x8x4_t, int8x16_t, int8x16x2_t, int8x16x3_t, int8x16x4_t, int16x4_t,
int16x8_t, int32x2_t, int32x4_t, int64x1_t, int64x2_t, poly8x8_t, poly8x8x2_t, poly8x8x3_t,
poly8x8x4_t, poly8x16_t, poly8x16x2_t, poly8x16x3_t, poly8x16x4_t, poly16x4_t, poly16x8_t,
poly64x1_t, poly64x2_t, uint8x8_t, uint8x8x2_t, uint8x8x3_t, uint8x8x4_t, uint8x16_t,
uint8x16x2_t, uint8x16x3_t, uint8x16x4_t, uint16x4_t, uint16x4x2_t, uint16x4x3_t,
uint16x4x4_t, uint16x8_t, uint32x2_t, uint32x4_t, uint64x1_t, uint64x2_t
);
}
}
}
