diff options
| -rw-r--r-- | src/bytes_mut.rs | 30 | ||||
| -rw-r--r-- | tests/test_bytes_vec_alloc.rs | 11 |
2 files changed, 31 insertions, 10 deletions
diff --git a/src/bytes_mut.rs b/src/bytes_mut.rs index cc1a3ba..4f9a885 100644 --- a/src/bytes_mut.rs +++ b/src/bytes_mut.rs @@ -253,7 +253,7 @@ impl BytesMut { let ptr = self.ptr.as_ptr(); let len = self.len; - let data = AtomicPtr::new(self.data as _); + let data = AtomicPtr::new(self.data.cast()); mem::forget(self); unsafe { Bytes::with_vtable(ptr, len, data, &SHARED_VTABLE) } } @@ -613,7 +613,7 @@ impl BytesMut { } debug_assert_eq!(kind, KIND_ARC); - let shared: *mut Shared = self.data as _; + let shared: *mut Shared = self.data; // Reserving involves abandoning the currently shared buffer and // allocating a new vector with the requested capacity. @@ -692,7 +692,7 @@ impl BytesMut { // Update self let data = (original_capacity_repr << ORIGINAL_CAPACITY_OFFSET) | KIND_VEC; - self.data = data as _; + self.data = invalid_ptr(data); self.ptr = vptr(v.as_mut_ptr()); self.len = v.len(); self.cap = v.capacity(); @@ -723,7 +723,7 @@ impl BytesMut { // Reserved above debug_assert!(dst.len() >= cnt); - ptr::copy_nonoverlapping(extend.as_ptr(), dst.as_mut_ptr() as *mut u8, cnt); + ptr::copy_nonoverlapping(extend.as_ptr(), dst.as_mut_ptr(), cnt); } unsafe { @@ -788,7 +788,7 @@ impl BytesMut { ptr, len, cap, - data: data as *mut _, + data: invalid_ptr(data), } } @@ -909,7 +909,7 @@ impl BytesMut { // always succeed. debug_assert_eq!(shared as usize & KIND_MASK, KIND_ARC); - self.data = shared as _; + self.data = shared; } /// Makes an exact shallow clone of `self`. @@ -942,7 +942,7 @@ impl BytesMut { debug_assert_eq!(self.kind(), KIND_VEC); debug_assert!(pos <= MAX_VEC_POS); - self.data = ((pos << VEC_POS_OFFSET) | (prev & NOT_VEC_POS_MASK)) as *mut _; + self.data = invalid_ptr((pos << VEC_POS_OFFSET) | (prev & NOT_VEC_POS_MASK)); } #[inline] @@ -968,7 +968,7 @@ impl Drop for BytesMut { let _ = rebuild_vec(self.ptr.as_ptr(), self.len, self.cap, off); } } else if kind == KIND_ARC { - unsafe { release_shared(self.data as _) }; + unsafe { release_shared(self.data) }; } } } @@ -1549,6 +1549,18 @@ fn vptr(ptr: *mut u8) -> NonNull<u8> { } } +/// Returns a dangling pointer with the given address. This is used to store +/// integer data in pointer fields. +/// +/// It is equivalent to `addr as *mut T`, but this fails on miri when strict +/// provenance checking is enabled. +#[inline] +fn invalid_ptr<T>(addr: usize) -> *mut T { + let ptr = core::ptr::null_mut::<u8>().wrapping_add(addr); + debug_assert_eq!(ptr as usize, addr); + ptr.cast::<T>() +} + unsafe fn rebuild_vec(ptr: *mut u8, mut len: usize, mut cap: usize, off: usize) -> Vec<u8> { let ptr = ptr.offset(-(off as isize)); len += off; @@ -1568,7 +1580,7 @@ unsafe fn shared_v_clone(data: &AtomicPtr<()>, ptr: *const u8, len: usize) -> By let shared = data.load(Ordering::Relaxed) as *mut Shared; increment_shared(shared); - let data = AtomicPtr::new(shared as _); + let data = AtomicPtr::new(shared as *mut ()); Bytes::with_vtable(ptr, len, data, &SHARED_VTABLE) } diff --git a/tests/test_bytes_vec_alloc.rs b/tests/test_bytes_vec_alloc.rs index 9d98232..752009f 100644 --- a/tests/test_bytes_vec_alloc.rs +++ b/tests/test_bytes_vec_alloc.rs @@ -45,7 +45,7 @@ impl Ledger { if entry_ptr .compare_exchange( ptr, - usize::MAX as *mut u8, + invalid_ptr(usize::MAX), Ordering::SeqCst, Ordering::SeqCst, ) @@ -103,3 +103,12 @@ fn test_bytes_truncate_and_advance() { bytes.advance(1); drop(bytes); } + +/// Returns a dangling pointer with the given address. This is used to store +/// integer data in pointer fields. +#[inline] +fn invalid_ptr<T>(addr: usize) -> *mut T { + let ptr = std::ptr::null_mut::<u8>().wrapping_add(addr); + debug_assert_eq!(ptr as usize, addr); + ptr.cast::<T>() +} |