diff options
| -rw-r--r-- | crates/core_simd/src/simd/ptr/const_ptr.rs | 21 | ||||
| -rw-r--r-- | crates/core_simd/src/simd/ptr/mut_ptr.rs | 21 |
2 files changed, 42 insertions, 0 deletions
diff --git a/crates/core_simd/src/simd/ptr/const_ptr.rs b/crates/core_simd/src/simd/ptr/const_ptr.rs index e217d1c8c87..2e7654347c0 100644 --- a/crates/core_simd/src/simd/ptr/const_ptr.rs +++ b/crates/core_simd/src/simd/ptr/const_ptr.rs @@ -42,6 +42,19 @@ pub trait SimdConstPtr: Copy + Sealed { /// Equivalent to calling [`pointer::addr`] on each element. fn addr(self) -> Self::Usize; + /// Convert an address to a pointer without giving it any provenance. + /// + /// Without provenance, this pointer is not associated with any actual allocation. Such a + /// no-provenance pointer may be used for zero-sized memory accesses (if suitably aligned), but + /// non-zero-sized memory accesses with a no-provenance pointer are UB. No-provenance pointers + /// are little more than a usize address in disguise. + /// + /// This is different from [`Self::from_exposed_addr`], which creates a pointer that picks up a + /// previously exposed provenance. + /// + /// Equivalent to calling [`core::ptr::without_provenance`] on each element. + fn without_provenance(addr: Self::Usize) -> Self; + /// Creates a new pointer with the given address. /// /// This performs the same operation as a cast, but copies the *address-space* and @@ -119,6 +132,14 @@ where } #[inline] + fn without_provenance(addr: Self::Usize) -> Self { + // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic. + // SAFETY: Integer-to-pointer transmutes are valid (if you are okay with not getting any + // provenance). + unsafe { core::mem::transmute_copy(&addr) } + } + + #[inline] fn with_addr(self, addr: Self::Usize) -> Self { // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic. // diff --git a/crates/core_simd/src/simd/ptr/mut_ptr.rs b/crates/core_simd/src/simd/ptr/mut_ptr.rs index 5cb27af4fde..5323bb74f6f 100644 --- a/crates/core_simd/src/simd/ptr/mut_ptr.rs +++ b/crates/core_simd/src/simd/ptr/mut_ptr.rs @@ -39,6 +39,19 @@ pub trait SimdMutPtr: Copy + Sealed { /// Equivalent to calling [`pointer::addr`] on each element. fn addr(self) -> Self::Usize; + /// Convert an address to a pointer without giving it any provenance. + /// + /// Without provenance, this pointer is not associated with any actual allocation. Such a + /// no-provenance pointer may be used for zero-sized memory accesses (if suitably aligned), but + /// non-zero-sized memory accesses with a no-provenance pointer are UB. No-provenance pointers + /// are little more than a usize address in disguise. + /// + /// This is different from [`Self::from_exposed_addr`], which creates a pointer that picks up a + /// previously exposed provenance. + /// + /// Equivalent to calling [`core::ptr::without_provenance`] on each element. + fn without_provenance(addr: Self::Usize) -> Self; + /// Creates a new pointer with the given address. /// /// This performs the same operation as a cast, but copies the *address-space* and @@ -116,6 +129,14 @@ where } #[inline] + fn without_provenance(addr: Self::Usize) -> Self { + // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic. + // SAFETY: Integer-to-pointer transmutes are valid (if you are okay with not getting any + // provenance). + unsafe { core::mem::transmute_copy(&addr) } + } + + #[inline] fn with_addr(self, addr: Self::Usize) -> Self { // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic. // |