1use super::*;
2
3/// Marker trait for "plain old data".
4///
5/// The point of this trait is that once something is marked "plain old data"
6/// you can really go to town with the bit fiddling and bit casting. Therefore,
7/// it's a relatively strong claim to make about a type. Do not add this to your
8/// type casually.
9///
10/// **Reminder:** The results of casting around bytes between data types are
11/// _endian dependant_. Little-endian machines are the most common, but
12/// big-endian machines do exist (and big-endian is also used for "network
13/// order" bytes).
14///
15/// ## Safety
16///
17/// * The type must be inhabited (eg: no
18/// [Infallible](core::convert::Infallible)).
19/// * The type must allow any bit pattern (eg: no `bool` or `char`, which have
20/// illegal bit patterns).
21/// * The type must not contain any uninit (or padding) bytes, either in the
22/// middle or on the end (eg: no `#[repr(C)] struct Foo(u8, u16)`, which has
23/// padding in the middle, and also no `#[repr(C)] struct Foo(u16, u8)`, which
24/// has padding on the end).
25/// * The type needs to have all fields also be `Pod`.
26/// * The type needs to be `repr(C)` or `repr(transparent)`. In the case of
27/// `repr(C)`, the `packed` and `align` repr modifiers can be used as long as
28/// all other rules end up being followed.
29/// * It is disallowed for types to contain pointer types, `Cell`, `UnsafeCell`,
30/// atomics, and any other forms of interior mutability.
31/// * More precisely: A shared reference to the type must allow reads, and
32/// *only* reads. RustBelt's separation logic is based on the notion that a
33/// type is allowed to define a sharing predicate, its own invariant that must
34/// hold for shared references, and this predicate is the reasoning that allow
35/// it to deal with atomic and cells etc. We require the sharing predicate to
36/// be trivial and permit only read-only access.
37pub unsafe trait Pod: Zeroable + Copy + 'static {}
38
39unsafe impl Pod for () {}
40unsafe impl Pod for u8 {}
41unsafe impl Pod for i8 {}
42unsafe impl Pod for u16 {}
43unsafe impl Pod for i16 {}
44unsafe impl Pod for u32 {}
45unsafe impl Pod for i32 {}
46unsafe impl Pod for u64 {}
47unsafe impl Pod for i64 {}
48unsafe impl Pod for usize {}
49unsafe impl Pod for isize {}
50unsafe impl Pod for u128 {}
51unsafe impl Pod for i128 {}
52#[cfg(feature = "nightly_float")]
53unsafe impl Pod for f16 {}
54unsafe impl Pod for f32 {}
55unsafe impl Pod for f64 {}
56#[cfg(feature = "nightly_float")]
57unsafe impl Pod for f128 {}
58unsafe impl<T: Pod> Pod for Wrapping<T> {}
59
60#[cfg(feature = "pod_saturating")]
61unsafe impl<T: Pod> Pod for core::num::Saturating<T>{}
62
63#[cfg(feature = "unsound_ptr_pod_impl")]
64#[cfg_attr(
65 feature = "nightly_docs",
66 doc(cfg(feature = "unsound_ptr_pod_impl"))
67)]
68unsafe impl<T: 'static> Pod for *mut T {}
69#[cfg(feature = "unsound_ptr_pod_impl")]
70#[cfg_attr(
71 feature = "nightly_docs",
72 doc(cfg(feature = "unsound_ptr_pod_impl"))
73)]
74unsafe impl<T: 'static> Pod for *const T {}
75#[cfg(feature = "unsound_ptr_pod_impl")]
76#[cfg_attr(
77 feature = "nightly_docs",
78 doc(cfg(feature = "unsound_ptr_pod_impl"))
79)]
80unsafe impl<T: 'static> PodInOption for NonNull<T> {}
81
82unsafe impl<T: ?Sized + 'static> Pod for PhantomData<T> {}
83unsafe impl Pod for PhantomPinned {}
84unsafe impl<T: Pod> Pod for core::mem::ManuallyDrop<T> {}
85
86// Note(Lokathor): MaybeUninit can NEVER be Pod.
87
88#[cfg(feature = "min_const_generics")]
89#[cfg_attr(feature = "nightly_docs", doc(cfg(feature = "min_const_generics")))]
90unsafe impl<T, const N: usize> Pod for [T; N] where T: Pod {}
91
92#[cfg(not(feature = "min_const_generics"))]
93impl_unsafe_marker_for_array!(
94 Pod, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
95 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 48, 64, 96, 128, 256,
96 512, 1024, 2048, 4096
97);
98
99impl_unsafe_marker_for_simd!(
100 #[cfg(all(target_arch = "wasm32", feature = "wasm_simd"))]
101 unsafe impl Pod for wasm32::{v128}
102);
103
104impl_unsafe_marker_for_simd!(
105 #[cfg(all(target_arch = "aarch64", feature = "aarch64_simd"))]
106 unsafe impl Pod for aarch64::{
107 float32x2_t, float32x2x2_t, float32x2x3_t, float32x2x4_t, float32x4_t,
108 float32x4x2_t, float32x4x3_t, float32x4x4_t, float64x1_t, float64x1x2_t,
109 float64x1x3_t, float64x1x4_t, float64x2_t, float64x2x2_t, float64x2x3_t,
110 float64x2x4_t, int16x4_t, int16x4x2_t, int16x4x3_t, int16x4x4_t, int16x8_t,
111 int16x8x2_t, int16x8x3_t, int16x8x4_t, int32x2_t, int32x2x2_t, int32x2x3_t,
112 int32x2x4_t, int32x4_t, int32x4x2_t, int32x4x3_t, int32x4x4_t, int64x1_t,
113 int64x1x2_t, int64x1x3_t, int64x1x4_t, int64x2_t, int64x2x2_t, int64x2x3_t,
114 int64x2x4_t, int8x16_t, int8x16x2_t, int8x16x3_t, int8x16x4_t, int8x8_t,
115 int8x8x2_t, int8x8x3_t, int8x8x4_t, poly16x4_t, poly16x4x2_t, poly16x4x3_t,
116 poly16x4x4_t, poly16x8_t, poly16x8x2_t, poly16x8x3_t, poly16x8x4_t,
117 poly64x1_t, poly64x1x2_t, poly64x1x3_t, poly64x1x4_t, poly64x2_t,
118 poly64x2x2_t, poly64x2x3_t, poly64x2x4_t, poly8x16_t, poly8x16x2_t,
119 poly8x16x3_t, poly8x16x4_t, poly8x8_t, poly8x8x2_t, poly8x8x3_t, poly8x8x4_t,
120 uint16x4_t, uint16x4x2_t, uint16x4x3_t, uint16x4x4_t, uint16x8_t,
121 uint16x8x2_t, uint16x8x3_t, uint16x8x4_t, uint32x2_t, uint32x2x2_t,
122 uint32x2x3_t, uint32x2x4_t, uint32x4_t, uint32x4x2_t, uint32x4x3_t,
123 uint32x4x4_t, uint64x1_t, uint64x1x2_t, uint64x1x3_t, uint64x1x4_t,
124 uint64x2_t, uint64x2x2_t, uint64x2x3_t, uint64x2x4_t, uint8x16_t,
125 uint8x16x2_t, uint8x16x3_t, uint8x16x4_t, uint8x8_t, uint8x8x2_t,
126 uint8x8x3_t, uint8x8x4_t,
127 }
128);
129
130impl_unsafe_marker_for_simd!(
131 #[cfg(target_arch = "x86")]
132 unsafe impl Pod for x86::{
133 __m128i, __m128, __m128d,
134 __m256i, __m256, __m256d,
135 }
136);
137
138impl_unsafe_marker_for_simd!(
139 #[cfg(target_arch = "x86_64")]
140 unsafe impl Pod for x86_64::{
141 __m128i, __m128, __m128d,
142 __m256i, __m256, __m256d,
143 }
144);
145
146#[cfg(feature = "nightly_portable_simd")]
147#[cfg_attr(
148 feature = "nightly_docs",
149 doc(cfg(feature = "nightly_portable_simd"))
150)]
151unsafe impl<T, const N: usize> Pod for core::simd::Simd<T, N>
152where
153 T: core::simd::SimdElement + Pod,
154 core::simd::LaneCount<N>: core::simd::SupportedLaneCount,
155{
156}
157
158impl_unsafe_marker_for_simd!(
159 #[cfg(all(target_arch = "x86", any(feature = "nightly_stdsimd", feature = "avx512_simd")))]
160 unsafe impl Pod for x86::{
161 __m512, __m512d, __m512i
162 }
163);
164
165impl_unsafe_marker_for_simd!(
166 #[cfg(all(target_arch = "x86_64", any(feature = "nightly_stdsimd", feature = "avx512_simd")))]
167 unsafe impl Pod for x86_64::{
168 __m512, __m512d, __m512i
169 }
170);
171
172impl_unsafe_marker_for_simd!(
173 #[cfg(all(target_arch = "x86", feature = "nightly_stdsimd"))]
174 unsafe impl Pod for x86::{
175 __m128bh, __m256bh, __m512bh
176 }
177);
178
179impl_unsafe_marker_for_simd!(
180 #[cfg(all(target_arch = "x86_64", feature = "nightly_stdsimd"))]
181 unsafe impl Pod for x86_64::{
182 __m128bh, __m256bh, __m512bh
183 }
184);
185