1use super::sealed::Sealed;
2use crate::simd::{
3 cmp::SimdPartialEq, intrinsics, num::SimdUint, LaneCount, Mask, Simd, SupportedLaneCount,
4};
5
6/// Operations on SIMD vectors of mutable pointers.
7pub trait SimdMutPtr: Copy + Sealed {
8 /// Vector of `usize` with the same number of elements.
9 type Usize;
10
11 /// Vector of `isize` with the same number of elements.
12 type Isize;
13
14 /// Vector of const pointers with the same number of elements.
15 type CastPtr<T>;
16
17 /// Vector of constant pointers to the same type.
18 type ConstPtr;
19
20 /// Mask type used for manipulating this SIMD vector type.
21 type Mask;
22
23 /// Returns `true` for each element that is null.
24 fn is_null(self) -> Self::Mask;
25
26 /// Casts to a pointer of another type.
27 ///
28 /// Equivalent to calling [`pointer::cast`] on each element.
29 fn cast<T>(self) -> Self::CastPtr<T>;
30
31 /// Changes constness without changing the type.
32 ///
33 /// Equivalent to calling [`pointer::cast_const`] on each element.
34 fn cast_const(self) -> Self::ConstPtr;
35
36 /// Gets the "address" portion of the pointer.
37 ///
38 /// This method discards pointer semantic metadata, so the result cannot be
39 /// directly cast into a valid pointer.
40 ///
41 /// Equivalent to calling [`pointer::addr`] on each element.
42 fn addr(self) -> Self::Usize;
43
44 /// Creates a new pointer with the given address.
45 ///
46 /// This performs the same operation as a cast, but copies the *address-space* and
47 /// *provenance* of `self` to the new pointer.
48 ///
49 /// Equivalent to calling [`pointer::with_addr`] on each element.
50 fn with_addr(self, addr: Self::Usize) -> Self;
51
52 /// Gets the "address" portion of the pointer, and "exposes" the provenance part for future use
53 /// in [`Self::from_exposed_addr`].
54 fn expose_addr(self) -> Self::Usize;
55
56 /// Convert an address back to a pointer, picking up a previously "exposed" provenance.
57 ///
58 /// Equivalent to calling [`core::ptr::from_exposed_addr_mut`] on each element.
59 fn from_exposed_addr(addr: Self::Usize) -> Self;
60
61 /// Calculates the offset from a pointer using wrapping arithmetic.
62 ///
63 /// Equivalent to calling [`pointer::wrapping_offset`] on each element.
64 fn wrapping_offset(self, offset: Self::Isize) -> Self;
65
66 /// Calculates the offset from a pointer using wrapping arithmetic.
67 ///
68 /// Equivalent to calling [`pointer::wrapping_add`] on each element.
69 fn wrapping_add(self, count: Self::Usize) -> Self;
70
71 /// Calculates the offset from a pointer using wrapping arithmetic.
72 ///
73 /// Equivalent to calling [`pointer::wrapping_sub`] on each element.
74 fn wrapping_sub(self, count: Self::Usize) -> Self;
75}
76
77impl<T, const N: usize> Sealed for Simd<*mut T, N> where LaneCount<N>: SupportedLaneCount {}
78
79impl<T, const N: usize> SimdMutPtr for Simd<*mut T, N>
80where
81 LaneCount<N>: SupportedLaneCount,
82{
83 type Usize = Simd<usize, N>;
84 type Isize = Simd<isize, N>;
85 type CastPtr<U> = Simd<*mut U, N>;
86 type ConstPtr = Simd<*const T, N>;
87 type Mask = Mask<isize, N>;
88
89 #[inline]
90 fn is_null(self) -> Self::Mask {
91 Simd::splat(core::ptr::null_mut()).simd_eq(self)
92 }
93
94 #[inline]
95 fn cast<U>(self) -> Self::CastPtr<U> {
96 // SimdElement currently requires zero-sized metadata, so this should never fail.
97 // If this ever changes, `simd_cast_ptr` should produce a post-mono error.
98 use core::{mem::size_of, ptr::Pointee};
99 assert_eq!(size_of::<<T as Pointee>::Metadata>(), 0);
100 assert_eq!(size_of::<<U as Pointee>::Metadata>(), 0);
101
102 // Safety: pointers can be cast
103 unsafe { intrinsics::simd_cast_ptr(self) }
104 }
105
106 #[inline]
107 fn cast_const(self) -> Self::ConstPtr {
108 // Safety: pointers can be cast
109 unsafe { intrinsics::simd_cast_ptr(self) }
110 }
111
112 #[inline]
113 fn addr(self) -> Self::Usize {
114 // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
115 // SAFETY: Pointer-to-integer transmutes are valid (if you are okay with losing the
116 // provenance).
117 unsafe { core::mem::transmute_copy(&self) }
118 }
119
120 #[inline]
121 fn with_addr(self, addr: Self::Usize) -> Self {
122 // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
123 //
124 // In the mean-time, this operation is defined to be "as if" it was
125 // a wrapping_offset, so we can emulate it as such. This should properly
126 // restore pointer provenance even under today's compiler.
127 self.cast::<u8>()
128 .wrapping_offset(addr.cast::<isize>() - self.addr().cast::<isize>())
129 .cast()
130 }
131
132 #[inline]
133 fn expose_addr(self) -> Self::Usize {
134 // Safety: `self` is a pointer vector
135 unsafe { intrinsics::simd_expose_addr(self) }
136 }
137
138 #[inline]
139 fn from_exposed_addr(addr: Self::Usize) -> Self {
140 // Safety: `self` is a pointer vector
141 unsafe { intrinsics::simd_from_exposed_addr(addr) }
142 }
143
144 #[inline]
145 fn wrapping_offset(self, count: Self::Isize) -> Self {
146 // Safety: simd_arith_offset takes a vector of pointers and a vector of offsets
147 unsafe { intrinsics::simd_arith_offset(self, count) }
148 }
149
150 #[inline]
151 fn wrapping_add(self, count: Self::Usize) -> Self {
152 self.wrapping_offset(count.cast())
153 }
154
155 #[inline]
156 fn wrapping_sub(self, count: Self::Usize) -> Self {
157 self.wrapping_offset(-count.cast::<isize>())
158 }
159}
160