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| author | Caleb Zulawski <caleb.zulawski@gmail.com> | 2022-06-26 10:07:48 -0400 |
|---|---|---|
| committer | Caleb Zulawski <caleb.zulawski@gmail.com> | 2022-10-29 11:55:01 -0400 |
| commit | 8a5a5732a1527fbdffbc825ae630d911fc130e2e (patch) | |
| tree | beb013b2159ce1dde8b671fdc457a6e4889d871f | |
| parent | e7cc021189f1d18974057d60223bdbb5abd4dc15 (diff) | |
| download | rust-8a5a5732a1527fbdffbc825ae630d911fc130e2e.tar.gz rust-8a5a5732a1527fbdffbc825ae630d911fc130e2e.zip | |
Clarify addr and with_addr implementations
| -rw-r--r-- | crates/core_simd/src/elements/const_ptr.rs | 14 | ||||
| -rw-r--r-- | crates/core_simd/src/elements/mut_ptr.rs | 14 |
2 files changed, 18 insertions, 10 deletions
diff --git a/crates/core_simd/src/elements/const_ptr.rs b/crates/core_simd/src/elements/const_ptr.rs index 5a5faad23c8..3485d31e44d 100644 --- a/crates/core_simd/src/elements/const_ptr.rs +++ b/crates/core_simd/src/elements/const_ptr.rs @@ -83,17 +83,21 @@ where #[inline] fn addr(self) -> Self::Usize { - // Safety: Since `addr` discards provenance, this is safe. + // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic. + // SAFETY: Pointer-to-integer transmutes are valid (if you are okay with losing the + // provenance). unsafe { core::mem::transmute_copy(&self) } - - //TODO switch to casts when available - //self.cast() } #[inline] - fn with_addr(self, addr: Self::Usize) -> Self { + fn with_addr(self, _addr: Self::Usize) -> Self { unimplemented!() /* + // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic. + // + // In the mean-time, this operation is defined to be "as if" it was + // a wrapping_offset, so we can emulate it as such. This should properly + // restore pointer provenance even under today's compiler. self.cast::<*const u8>() .wrapping_offset(addr.cast::<isize>() - self.addr().cast::<isize>()) .cast() diff --git a/crates/core_simd/src/elements/mut_ptr.rs b/crates/core_simd/src/elements/mut_ptr.rs index d7b05af0eac..39fe9f35621 100644 --- a/crates/core_simd/src/elements/mut_ptr.rs +++ b/crates/core_simd/src/elements/mut_ptr.rs @@ -78,17 +78,21 @@ where #[inline] fn addr(self) -> Self::Usize { - // Safety: Since `addr` discards provenance, this is safe. + // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic. + // SAFETY: Pointer-to-integer transmutes are valid (if you are okay with losing the + // provenance). unsafe { core::mem::transmute_copy(&self) } - - //TODO switch to casts when available - //self.cast() } #[inline] - fn with_addr(self, addr: Self::Usize) -> Self { + fn with_addr(self, _addr: Self::Usize) -> Self { unimplemented!() /* + // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic. + // + // In the mean-time, this operation is defined to be "as if" it was + // a wrapping_offset, so we can emulate it as such. This should properly + // restore pointer provenance even under today's compiler. self.cast::<*mut u8>() .wrapping_offset(addr.cast::<isize>() - self.addr().cast::<isize>()) .cast() |