diff --git a/src/libcore/fmt/float.rs b/src/libcore/fmt/float.rs index 03e7a9a49d8a7..d01cd012031db 100644 --- a/src/libcore/fmt/float.rs +++ b/src/libcore/fmt/float.rs @@ -9,7 +9,7 @@ // except according to those terms. use fmt::{Formatter, Result, LowerExp, UpperExp, Display, Debug}; -use mem; +use mem::MaybeUninit; use num::flt2dec; // Don't inline this so callers don't use the stack space this function @@ -20,11 +20,11 @@ fn float_to_decimal_common_exact(fmt: &mut Formatter, num: &T, where T: flt2dec::DecodableFloat { unsafe { - let mut buf: [u8; 1024] = mem::uninitialized(); // enough for f32 and f64 - let mut parts: [flt2dec::Part; 4] = mem::uninitialized(); + let mut buf = MaybeUninit::<[u8; 1024]>::uninitialized(); // enough for f32 and f64 + let mut parts = MaybeUninit::<[flt2dec::Part; 4]>::uninitialized(); let formatted = flt2dec::to_exact_fixed_str(flt2dec::strategy::grisu::format_exact, *num, sign, precision, - false, &mut buf, &mut parts); + false, buf.get_mut(), parts.get_mut()); fmt.pad_formatted_parts(&formatted) } } @@ -38,10 +38,11 @@ fn float_to_decimal_common_shortest(fmt: &mut Formatter, num: &T, { unsafe { // enough for f32 and f64 - let mut buf: [u8; flt2dec::MAX_SIG_DIGITS] = mem::uninitialized(); - let mut parts: [flt2dec::Part; 4] = mem::uninitialized(); + let mut buf = MaybeUninit::<[u8; flt2dec::MAX_SIG_DIGITS]>::uninitialized(); + let mut parts = MaybeUninit::<[flt2dec::Part; 4]>::uninitialized(); let formatted = flt2dec::to_shortest_str(flt2dec::strategy::grisu::format_shortest, *num, - sign, precision, false, &mut buf, &mut parts); + sign, precision, false, buf.get_mut(), + parts.get_mut()); fmt.pad_formatted_parts(&formatted) } } @@ -75,11 +76,11 @@ fn float_to_exponential_common_exact(fmt: &mut Formatter, num: &T, where T: flt2dec::DecodableFloat { unsafe { - let mut buf: [u8; 1024] = mem::uninitialized(); // enough for f32 and f64 - let mut parts: [flt2dec::Part; 6] = mem::uninitialized(); + let mut buf = MaybeUninit::<[u8; 1024]>::uninitialized(); // enough for f32 and f64 + let mut parts = MaybeUninit::<[flt2dec::Part; 6]>::uninitialized(); let formatted = flt2dec::to_exact_exp_str(flt2dec::strategy::grisu::format_exact, *num, sign, precision, - upper, &mut buf, &mut parts); + upper, buf.get_mut(), parts.get_mut()); fmt.pad_formatted_parts(&formatted) } } @@ -94,11 +95,11 @@ fn float_to_exponential_common_shortest(fmt: &mut Formatter, { unsafe { // enough for f32 and f64 - let mut buf: [u8; flt2dec::MAX_SIG_DIGITS] = mem::uninitialized(); - let mut parts: [flt2dec::Part; 6] = mem::uninitialized(); + let mut buf = MaybeUninit::<[u8; flt2dec::MAX_SIG_DIGITS]>::uninitialized(); + let mut parts = MaybeUninit::<[flt2dec::Part; 6]>::uninitialized(); let formatted = flt2dec::to_shortest_exp_str(flt2dec::strategy::grisu::format_shortest, *num, sign, (0, 0), upper, - &mut buf, &mut parts); + buf.get_mut(), parts.get_mut()); fmt.pad_formatted_parts(&formatted) } } diff --git a/src/libcore/mem.rs b/src/libcore/mem.rs index 56ba10c49f41f..a5603ff6a62e7 100644 --- a/src/libcore/mem.rs +++ b/src/libcore/mem.rs @@ -950,7 +950,7 @@ impl ManuallyDrop { /// ManuallyDrop::new(Box::new(())); /// ``` #[stable(feature = "manually_drop", since = "1.20.0")] - #[inline] + #[inline(always)] pub const fn new(value: T) -> ManuallyDrop { ManuallyDrop { value } } @@ -967,7 +967,7 @@ impl ManuallyDrop { /// let _: Box<()> = ManuallyDrop::into_inner(x); // This drops the `Box`. /// ``` #[stable(feature = "manually_drop", since = "1.20.0")] - #[inline] + #[inline(always)] pub const fn into_inner(slot: ManuallyDrop) -> T { slot.value } @@ -1015,7 +1015,7 @@ impl ManuallyDrop { #[stable(feature = "manually_drop", since = "1.20.0")] impl Deref for ManuallyDrop { type Target = T; - #[inline] + #[inline(always)] fn deref(&self) -> &T { &self.value } @@ -1023,7 +1023,7 @@ impl Deref for ManuallyDrop { #[stable(feature = "manually_drop", since = "1.20.0")] impl DerefMut for ManuallyDrop { - #[inline] + #[inline(always)] fn deref_mut(&mut self) -> &mut T { &mut self.value } @@ -1044,6 +1044,7 @@ impl MaybeUninit { /// Note that dropping a `MaybeUninit` will never call `T`'s drop code. /// It is your responsibility to make sure `T` gets dropped if it got initialized. #[unstable(feature = "maybe_uninit", issue = "53491")] + #[inline(always)] pub const fn new(val: T) -> MaybeUninit { MaybeUninit { value: ManuallyDrop::new(val) } } @@ -1053,6 +1054,7 @@ impl MaybeUninit { /// Note that dropping a `MaybeUninit` will never call `T`'s drop code. /// It is your responsibility to make sure `T` gets dropped if it got initialized. #[unstable(feature = "maybe_uninit", issue = "53491")] + #[inline(always)] pub const fn uninitialized() -> MaybeUninit { MaybeUninit { uninit: () } } @@ -1066,6 +1068,7 @@ impl MaybeUninit { /// Note that dropping a `MaybeUninit` will never call `T`'s drop code. /// It is your responsibility to make sure `T` gets dropped if it got initialized. #[unstable(feature = "maybe_uninit", issue = "53491")] + #[inline] pub fn zeroed() -> MaybeUninit { let mut u = MaybeUninit::::uninitialized(); unsafe { @@ -1076,6 +1079,7 @@ impl MaybeUninit { /// Set the value of the `MaybeUninit`. This overwrites any previous value without dropping it. #[unstable(feature = "maybe_uninit", issue = "53491")] + #[inline(always)] pub fn set(&mut self, val: T) { unsafe { self.value = ManuallyDrop::new(val); @@ -1091,6 +1095,7 @@ impl MaybeUninit { /// It is up to the caller to guarantee that the `MaybeUninit` really is in an initialized /// state, otherwise this will immediately cause undefined behavior. #[unstable(feature = "maybe_uninit", issue = "53491")] + #[inline(always)] pub unsafe fn into_inner(self) -> T { ManuallyDrop::into_inner(self.value) } @@ -1102,6 +1107,7 @@ impl MaybeUninit { /// It is up to the caller to guarantee that the `MaybeUninit` really is in an initialized /// state, otherwise this will immediately cause undefined behavior. #[unstable(feature = "maybe_uninit", issue = "53491")] + #[inline(always)] pub unsafe fn get_ref(&self) -> &T { &*self.value } @@ -1113,6 +1119,7 @@ impl MaybeUninit { /// It is up to the caller to guarantee that the `MaybeUninit` really is in an initialized /// state, otherwise this will immediately cause undefined behavior. #[unstable(feature = "maybe_uninit", issue = "53491")] + #[inline(always)] pub unsafe fn get_mut(&mut self) -> &mut T { &mut *self.value } @@ -1120,6 +1127,7 @@ impl MaybeUninit { /// Get a pointer to the contained value. Reading from this pointer will be undefined /// behavior unless the `MaybeUninit` is initialized. #[unstable(feature = "maybe_uninit", issue = "53491")] + #[inline(always)] pub fn as_ptr(&self) -> *const T { unsafe { &*self.value as *const T } } @@ -1127,6 +1135,7 @@ impl MaybeUninit { /// Get a mutable pointer to the contained value. Reading from this pointer will be undefined /// behavior unless the `MaybeUninit` is initialized. #[unstable(feature = "maybe_uninit", issue = "53491")] + #[inline(always)] pub fn as_mut_ptr(&mut self) -> *mut T { unsafe { &mut *self.value as *mut T } } diff --git a/src/libcore/ptr.rs b/src/libcore/ptr.rs index e9cf11424cae1..947b67e4e9af3 100644 --- a/src/libcore/ptr.rs +++ b/src/libcore/ptr.rs @@ -79,7 +79,7 @@ use ops::{CoerceUnsized, DispatchFromDyn}; use fmt; use hash; use marker::{PhantomData, Unsize}; -use mem; +use mem::{self, MaybeUninit}; use nonzero::NonZero; use cmp::Ordering::{self, Less, Equal, Greater}; @@ -295,17 +295,14 @@ pub const fn null_mut() -> *mut T { 0 as *mut T } #[inline] #[stable(feature = "rust1", since = "1.0.0")] pub unsafe fn swap(x: *mut T, y: *mut T) { - // Give ourselves some scratch space to work with - let mut tmp: T = mem::uninitialized(); + // Give ourselves some scratch space to work with. + // We do not have to worry about drops: `MaybeUninit` does nothing when dropped. + let mut tmp = MaybeUninit::::uninitialized(); // Perform the swap - copy_nonoverlapping(x, &mut tmp, 1); + copy_nonoverlapping(x, tmp.as_mut_ptr(), 1); copy(y, x, 1); // `x` and `y` may overlap - copy_nonoverlapping(&tmp, y, 1); - - // y and t now point to the same thing, but we need to completely forget `tmp` - // because it's no longer relevant. - mem::forget(tmp); + copy_nonoverlapping(tmp.get_ref(), y, 1); } /// Swaps `count * size_of::()` bytes between the two regions of memory @@ -392,8 +389,8 @@ unsafe fn swap_nonoverlapping_bytes(x: *mut u8, y: *mut u8, len: usize) { while i + block_size <= len { // Create some uninitialized memory as scratch space // Declaring `t` here avoids aligning the stack when this loop is unused - let mut t: Block = mem::uninitialized(); - let t = &mut t as *mut _ as *mut u8; + let mut t = mem::MaybeUninit::::uninitialized(); + let t = t.as_mut_ptr() as *mut u8; let x = x.add(i); let y = y.add(i); @@ -407,10 +404,10 @@ unsafe fn swap_nonoverlapping_bytes(x: *mut u8, y: *mut u8, len: usize) { if i < len { // Swap any remaining bytes - let mut t: UnalignedBlock = mem::uninitialized(); + let mut t = mem::MaybeUninit::::uninitialized(); let rem = len - i; - let t = &mut t as *mut _ as *mut u8; + let t = t.as_mut_ptr() as *mut u8; let x = x.add(i); let y = y.add(i); @@ -575,9 +572,9 @@ pub unsafe fn replace(dst: *mut T, mut src: T) -> T { #[inline] #[stable(feature = "rust1", since = "1.0.0")] pub unsafe fn read(src: *const T) -> T { - let mut tmp: T = mem::uninitialized(); - copy_nonoverlapping(src, &mut tmp, 1); - tmp + let mut tmp = MaybeUninit::::uninitialized(); + copy_nonoverlapping(src, tmp.as_mut_ptr(), 1); + tmp.into_inner() } /// Reads the value from `src` without moving it. This leaves the @@ -642,11 +639,11 @@ pub unsafe fn read(src: *const T) -> T { #[inline] #[stable(feature = "ptr_unaligned", since = "1.17.0")] pub unsafe fn read_unaligned(src: *const T) -> T { - let mut tmp: T = mem::uninitialized(); + let mut tmp = MaybeUninit::::uninitialized(); copy_nonoverlapping(src as *const u8, - &mut tmp as *mut T as *mut u8, + tmp.as_mut_ptr() as *mut u8, mem::size_of::()); - tmp + tmp.into_inner() } /// Overwrites a memory location with the given value without reading or diff --git a/src/libcore/slice/rotate.rs b/src/libcore/slice/rotate.rs index 0d182b8497452..07153735300b8 100644 --- a/src/libcore/slice/rotate.rs +++ b/src/libcore/slice/rotate.rs @@ -9,7 +9,7 @@ // except according to those terms. use cmp; -use mem; +use mem::{self, MaybeUninit}; use ptr; /// Rotation is much faster if it has access to a little bit of memory. This @@ -26,12 +26,6 @@ union RawArray { } impl RawArray { - fn new() -> Self { - unsafe { mem::uninitialized() } - } - fn ptr(&self) -> *mut T { - unsafe { &self.typed as *const T as *mut T } - } fn cap() -> usize { if mem::size_of::() == 0 { usize::max_value() @@ -88,8 +82,8 @@ pub unsafe fn ptr_rotate(mut left: usize, mid: *mut T, mut right: usize) { } } - let rawarray = RawArray::new(); - let buf = rawarray.ptr(); + let mut rawarray = MaybeUninit::>::uninitialized(); + let buf = &mut (*rawarray.as_mut_ptr()).typed as *mut [T; 2] as *mut T; let dim = mid.sub(left).add(right); if left <= right { diff --git a/src/libcore/slice/sort.rs b/src/libcore/slice/sort.rs index e4c1fd03f9eb3..affe84fbef91f 100644 --- a/src/libcore/slice/sort.rs +++ b/src/libcore/slice/sort.rs @@ -17,7 +17,7 @@ //! stable sorting implementation. use cmp; -use mem; +use mem::{self, MaybeUninit}; use ptr; /// When dropped, copies from `src` into `dest`. @@ -226,14 +226,14 @@ fn partition_in_blocks(v: &mut [T], pivot: &T, is_less: &mut F) -> usize let mut block_l = BLOCK; let mut start_l = ptr::null_mut(); let mut end_l = ptr::null_mut(); - let mut offsets_l: [u8; BLOCK] = unsafe { mem::uninitialized() }; + let mut offsets_l = MaybeUninit::<[u8; BLOCK]>::uninitialized(); // The current block on the right side (from `r.sub(block_r)` to `r`). let mut r = unsafe { l.add(v.len()) }; let mut block_r = BLOCK; let mut start_r = ptr::null_mut(); let mut end_r = ptr::null_mut(); - let mut offsets_r: [u8; BLOCK] = unsafe { mem::uninitialized() }; + let mut offsets_r = MaybeUninit::<[u8; BLOCK]>::uninitialized(); // FIXME: When we get VLAs, try creating one array of length `min(v.len(), 2 * BLOCK)` rather // than two fixed-size arrays of length `BLOCK`. VLAs might be more cache-efficient. @@ -272,8 +272,8 @@ fn partition_in_blocks(v: &mut [T], pivot: &T, is_less: &mut F) -> usize if start_l == end_l { // Trace `block_l` elements from the left side. - start_l = offsets_l.as_mut_ptr(); - end_l = offsets_l.as_mut_ptr(); + start_l = offsets_l.as_mut_ptr() as *mut u8; + end_l = offsets_l.as_mut_ptr() as *mut u8; let mut elem = l; for i in 0..block_l { @@ -288,8 +288,8 @@ fn partition_in_blocks(v: &mut [T], pivot: &T, is_less: &mut F) -> usize if start_r == end_r { // Trace `block_r` elements from the right side. - start_r = offsets_r.as_mut_ptr(); - end_r = offsets_r.as_mut_ptr(); + start_r = offsets_r.as_mut_ptr() as *mut u8; + end_r = offsets_r.as_mut_ptr() as *mut u8; let mut elem = r; for i in 0..block_r {