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Diffstat (limited to 'vendor/libc/src/fixed_width_ints.rs')
| -rw-r--r-- | vendor/libc/src/fixed_width_ints.rs | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/vendor/libc/src/fixed_width_ints.rs b/vendor/libc/src/fixed_width_ints.rs new file mode 100644 index 0000000..999de8f --- /dev/null +++ b/vendor/libc/src/fixed_width_ints.rs @@ -0,0 +1,99 @@ +//! This module contains type aliases for C's fixed-width integer types . +//! +//! These aliases are deprecated: use the Rust types instead. + +#[deprecated(since = "0.2.55", note = "Use i8 instead.")] +pub type int8_t = i8; +#[deprecated(since = "0.2.55", note = "Use i16 instead.")] +pub type int16_t = i16; +#[deprecated(since = "0.2.55", note = "Use i32 instead.")] +pub type int32_t = i32; +#[deprecated(since = "0.2.55", note = "Use i64 instead.")] +pub type int64_t = i64; +#[deprecated(since = "0.2.55", note = "Use u8 instead.")] +pub type uint8_t = u8; +#[deprecated(since = "0.2.55", note = "Use u16 instead.")] +pub type uint16_t = u16; +#[deprecated(since = "0.2.55", note = "Use u32 instead.")] +pub type uint32_t = u32; +#[deprecated(since = "0.2.55", note = "Use u64 instead.")] +pub type uint64_t = u64; + +cfg_if! { + if #[cfg(all(libc_int128, target_arch = "aarch64", not(target_os = "windows")))] { + // This introduces partial support for FFI with __int128 and + // equivalent types on platforms where Rust's definition is validated + // to match the standard C ABI of that platform. + // + // Rust does not guarantee u128/i128 are sound for FFI, and its + // definitions are in fact known to be incompatible. [0] + // + // However these problems aren't fundamental, and are just platform + // inconsistencies. Specifically at the time of this writing: + // + // * For x64 SysV ABIs (everything but Windows), the types are underaligned. + // * For all Windows ABIs, Microsoft doesn't actually officially define __int128, + // and as a result different implementations don't actually agree on its ABI. + // + // But on the other major aarch64 platforms (android, linux, ios, macos) we have + // validated that rustc has the right ABI for these types. This is important because + // aarch64 uses these types in some fundamental OS types like user_fpsimd_struct, + // which represents saved simd registers. + // + // Any API which uses these types will need to `#[ignore(improper_ctypes)]` + // until the upstream rust issue is resolved, but this at least lets us make + // progress on platforms where this type is important. + // + // The list of supported architectures and OSes is intentionally very restricted, + // as careful work needs to be done to verify that a particular platform + // has a conformant ABI. + // + // [0]: https://github.com/rust-lang/rust/issues/54341 + + /// C `__int128` (a GCC extension that's part of many ABIs) + pub type __int128 = i128; + /// C `unsigned __int128` (a GCC extension that's part of many ABIs) + pub type __uint128 = u128; + /// C __int128_t (alternate name for [__int128][]) + pub type __int128_t = i128; + /// C __uint128_t (alternate name for [__uint128][]) + pub type __uint128_t = u128; + + cfg_if! { + if #[cfg(libc_underscore_const_names)] { + macro_rules! static_assert_eq { + ($a:expr, $b:expr) => { + const _: [(); $a] = [(); $b]; + }; + } + + // NOTE: if you add more platforms to here, you may need to cfg + // these consts. They should always match the platform's values + // for `sizeof(__int128)` and `_Alignof(__int128)`. + const _SIZE_128: usize = 16; + const _ALIGN_128: usize = 16; + + // Since Rust doesn't officially guarantee that these types + // have compatible ABIs, we const assert that these values have the + // known size/align of the target platform's libc. If rustc ever + // tries to regress things, it will cause a compilation error. + // + // This isn't a bullet-proof solution because e.g. it doesn't + // catch the fact that llvm and gcc disagree on how x64 __int128 + // is actually *passed* on the stack (clang underaligns it for + // the same reason that rustc *never* properly aligns it). + static_assert_eq!(core::mem::size_of::<__int128>(), _SIZE_128); + static_assert_eq!(core::mem::align_of::<__int128>(), _ALIGN_128); + + static_assert_eq!(core::mem::size_of::<__uint128>(), _SIZE_128); + static_assert_eq!(core::mem::align_of::<__uint128>(), _ALIGN_128); + + static_assert_eq!(core::mem::size_of::<__int128_t>(), _SIZE_128); + static_assert_eq!(core::mem::align_of::<__int128_t>(), _ALIGN_128); + + static_assert_eq!(core::mem::size_of::<__uint128_t>(), _SIZE_128); + static_assert_eq!(core::mem::align_of::<__uint128_t>(), _ALIGN_128); + } + } + } +} |