diff options
| -rw-r--r-- | src/libcore/ptr/const_ptr.rs | 755 | ||||
| -rw-r--r-- | src/libcore/ptr/mod.rs | 1696 | ||||
| -rw-r--r-- | src/libcore/ptr/mut_ptr.rs | 925 | ||||
| -rw-r--r-- | src/librustc/hir/mod.rs | 10 | ||||
| -rw-r--r-- | src/librustc/middle/region.rs | 10 | ||||
| -rw-r--r-- | src/librustc_mir/borrow_check/diagnostics/region_errors.rs | 37 | ||||
| -rw-r--r-- | src/librustc_mir/borrow_check/region_infer/mod.rs | 147 | ||||
| -rw-r--r-- | src/librustc_mir/dataflow/move_paths/builder.rs | 31 | ||||
| -rw-r--r-- | src/librustc_mir/transform/const_prop.rs | 52 | ||||
| -rw-r--r-- | src/librustc_typeck/check/generator_interior.rs | 21 | ||||
| -rw-r--r-- | src/test/mir-opt/const_prop/aggregate.rs | 2 | ||||
| -rw-r--r-- | src/test/mir-opt/const_prop/array_index.rs | 2 | ||||
| -rw-r--r-- | src/test/mir-opt/const_prop/optimizes_into_variable.rs | 149 | ||||
| -rw-r--r-- | src/test/mir-opt/const_prop/read_immutable_static.rs | 2 | ||||
| -rw-r--r-- | src/test/mir-opt/const_prop/repeat.rs | 2 | ||||
| -rw-r--r-- | src/test/ui/borrowck/move-from-union-field-issue-66500.rs | 30 | ||||
| -rw-r--r-- | src/test/ui/borrowck/move-from-union-field-issue-66500.stderr | 27 | ||||
| -rw-r--r-- | src/test/ui/consts/offset_from_ub.stderr | 20 |
18 files changed, 2090 insertions, 1828 deletions
diff --git a/src/libcore/ptr/const_ptr.rs b/src/libcore/ptr/const_ptr.rs new file mode 100644 index 00000000000..be2b7ff5f77 --- /dev/null +++ b/src/libcore/ptr/const_ptr.rs @@ -0,0 +1,755 @@ +use crate::cmp::Ordering::{self, Less, Equal, Greater}; +use crate::intrinsics; +use crate::mem; +use super::*; + +// ignore-tidy-undocumented-unsafe + +#[lang = "const_ptr"] +impl<T: ?Sized> *const T { + /// Returns `true` if the pointer is null. + /// + /// Note that unsized types have many possible null pointers, as only the + /// raw data pointer is considered, not their length, vtable, etc. + /// Therefore, two pointers that are null may still not compare equal to + /// each other. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// let s: &str = "Follow the rabbit"; + /// let ptr: *const u8 = s.as_ptr(); + /// assert!(!ptr.is_null()); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[inline] + pub fn is_null(self) -> bool { + // Compare via a cast to a thin pointer, so fat pointers are only + // considering their "data" part for null-ness. + (self as *const u8) == null() + } + + /// Casts to a pointer of another type. + #[stable(feature = "ptr_cast", since = "1.38.0")] + #[rustc_const_stable(feature = "const_ptr_cast", since = "1.38.0")] + #[inline] + pub const fn cast<U>(self) -> *const U { + self as _ + } + + /// Returns `None` if the pointer is null, or else returns a reference to + /// the value wrapped in `Some`. + /// + /// # Safety + /// + /// While this method and its mutable counterpart are useful for + /// null-safety, it is important to note that this is still an unsafe + /// operation because the returned value could be pointing to invalid + /// memory. + /// + /// When calling this method, you have to ensure that *either* the pointer is NULL *or* + /// all of the following is true: + /// - it is properly aligned + /// - it must point to an initialized instance of T; in particular, the pointer must be + /// "dereferencable" in the sense defined [here]. + /// + /// This applies even if the result of this method is unused! + /// (The part about being initialized is not yet fully decided, but until + /// it is, the only safe approach is to ensure that they are indeed initialized.) + /// + /// Additionally, the lifetime `'a` returned is arbitrarily chosen and does + /// not necessarily reflect the actual lifetime of the data. *You* must enforce + /// Rust's aliasing rules. In particular, for the duration of this lifetime, + /// the memory the pointer points to must not get mutated (except inside `UnsafeCell`). + /// + /// [here]: crate::ptr#safety + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// let ptr: *const u8 = &10u8 as *const u8; + /// + /// unsafe { + /// if let Some(val_back) = ptr.as_ref() { + /// println!("We got back the value: {}!", val_back); + /// } + /// } + /// ``` + /// + /// # Null-unchecked version + /// + /// If you are sure the pointer can never be null and are looking for some kind of + /// `as_ref_unchecked` that returns the `&T` instead of `Option<&T>`, know that you can + /// dereference the pointer directly. + /// + /// ``` + /// let ptr: *const u8 = &10u8 as *const u8; + /// + /// unsafe { + /// let val_back = &*ptr; + /// println!("We got back the value: {}!", val_back); + /// } + /// ``` + #[stable(feature = "ptr_as_ref", since = "1.9.0")] + #[inline] + pub unsafe fn as_ref<'a>(self) -> Option<&'a T> { + if self.is_null() { None } else { Some(&*self) } + } + + /// Calculates the offset from a pointer. + /// + /// `count` is in units of T; e.g., a `count` of 3 represents a pointer + /// offset of `3 * size_of::<T>()` bytes. + /// + /// # Safety + /// + /// If any of the following conditions are violated, the result is Undefined + /// Behavior: + /// + /// * Both the starting and resulting pointer must be either in bounds or one + /// byte past the end of the same allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// * The computed offset, **in bytes**, cannot overflow an `isize`. + /// + /// * The offset being in bounds cannot rely on "wrapping around" the address + /// space. That is, the infinite-precision sum, **in bytes** must fit in a usize. + /// + /// The compiler and standard library generally tries to ensure allocations + /// never reach a size where an offset is a concern. For instance, `Vec` + /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so + /// `vec.as_ptr().add(vec.len())` is always safe. + /// + /// Most platforms fundamentally can't even construct such an allocation. + /// For instance, no known 64-bit platform can ever serve a request + /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. + /// However, some 32-bit and 16-bit platforms may successfully serve a request for + /// more than `isize::MAX` bytes with things like Physical Address + /// Extension. As such, memory acquired directly from allocators or memory + /// mapped files *may* be too large to handle with this function. + /// + /// Consider using [`wrapping_offset`] instead if these constraints are + /// difficult to satisfy. The only advantage of this method is that it + /// enables more aggressive compiler optimizations. + /// + /// [`wrapping_offset`]: #method.wrapping_offset + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// let s: &str = "123"; + /// let ptr: *const u8 = s.as_ptr(); + /// + /// unsafe { + /// println!("{}", *ptr.offset(1) as char); + /// println!("{}", *ptr.offset(2) as char); + /// } + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[inline] + pub unsafe fn offset(self, count: isize) -> *const T + where + T: Sized, + { + intrinsics::offset(self, count) + } + + /// Calculates the offset from a pointer using wrapping arithmetic. + /// + /// `count` is in units of T; e.g., a `count` of 3 represents a pointer + /// offset of `3 * size_of::<T>()` bytes. + /// + /// # Safety + /// + /// The resulting pointer does not need to be in bounds, but it is + /// potentially hazardous to dereference (which requires `unsafe`). + /// + /// In particular, the resulting pointer remains attached to the same allocated + /// object that `self` points to. It may *not* be used to access a + /// different allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// In other words, `x.wrapping_offset(y.wrapping_offset_from(x))` is + /// *not* the same as `y`, and dereferencing it is undefined behavior + /// unless `x` and `y` point into the same allocated object. + /// + /// Compared to [`offset`], this method basically delays the requirement of staying + /// within the same allocated object: [`offset`] is immediate Undefined Behavior when + /// crossing object boundaries; `wrapping_offset` produces a pointer but still leads + /// to Undefined Behavior if that pointer is dereferenced. [`offset`] can be optimized + /// better and is thus preferrable in performance-sensitive code. + /// + /// If you need to cross object boundaries, cast the pointer to an integer and + /// do the arithmetic there. + /// + /// [`offset`]: #method.offset + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// // Iterate using a raw pointer in increments of two elements + /// let data = [1u8, 2, 3, 4, 5]; + /// let mut ptr: *const u8 = data.as_ptr(); + /// let step = 2; + /// let end_rounded_up = ptr.wrapping_offset(6); + /// + /// // This loop prints "1, 3, 5, " + /// while ptr != end_rounded_up { + /// unsafe { + /// print!("{}, ", *ptr); + /// } + /// ptr = ptr.wrapping_offset(step); + /// } + /// ``` + #[stable(feature = "ptr_wrapping_offset", since = "1.16.0")] + #[inline] + pub fn wrapping_offset(self, count: isize) -> *const T + where + T: Sized, + { + unsafe { intrinsics::arith_offset(self, count) } + } + + /// Calculates the distance between two pointers. The returned value is in + /// units of T: the distance in bytes is divided by `mem::size_of::<T>()`. + /// + /// This function is the inverse of [`offset`]. + /// + /// [`offset`]: #method.offset + /// [`wrapping_offset_from`]: #method.wrapping_offset_from + /// + /// # Safety + /// + /// If any of the following conditions are violated, the result is Undefined + /// Behavior: + /// + /// * Both the starting and other pointer must be either in bounds or one + /// byte past the end of the same allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// * The distance between the pointers, **in bytes**, cannot overflow an `isize`. + /// + /// * The distance between the pointers, in bytes, must be an exact multiple + /// of the size of `T`. + /// + /// * The distance being in bounds cannot rely on "wrapping around" the address space. + /// + /// The compiler and standard library generally try to ensure allocations + /// never reach a size where an offset is a concern. For instance, `Vec` + /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so + /// `ptr_into_vec.offset_from(vec.as_ptr())` is always safe. + /// + /// Most platforms fundamentally can't even construct such an allocation. + /// For instance, no known 64-bit platform can ever serve a request + /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. + /// However, some 32-bit and 16-bit platforms may successfully serve a request for + /// more than `isize::MAX` bytes with things like Physical Address + /// Extension. As such, memory acquired directly from allocators or memory + /// mapped files *may* be too large to handle with this function. + /// + /// Consider using [`wrapping_offset_from`] instead if these constraints are + /// difficult to satisfy. The only advantage of this method is that it + /// enables more aggressive compiler optimizations. + /// + /// # Panics + /// + /// This function panics if `T` is a Zero-Sized Type ("ZST"). + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(ptr_offset_from)] + /// + /// let a = [0; 5]; + /// let ptr1: *const i32 = &a[1]; + /// let ptr2: *const i32 = &a[3]; + /// unsafe { + /// assert_eq!(ptr2.offset_from(ptr1), 2); + /// assert_eq!(ptr1.offset_from(ptr2), -2); + /// assert_eq!(ptr1.offset(2), ptr2); + /// assert_eq!(ptr2.offset(-2), ptr1); + /// } + /// ``` + #[unstable(feature = "ptr_offset_from", issue = "41079")] + #[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "41079")] + #[inline] + pub const unsafe fn offset_from(self, origin: *const T) -> isize + where + T: Sized, + { + let pointee_size = mem::size_of::<T>(); + let ok = 0 < pointee_size && pointee_size <= isize::max_value() as usize; + // assert that the pointee size is valid in a const eval compatible way + // FIXME: do this with a real assert at some point + [()][(!ok) as usize]; + intrinsics::ptr_offset_from(self, origin) + } + + /// Calculates the distance between two pointers. The returned value is in + /// units of T: the distance in bytes is divided by `mem::size_of::<T>()`. + /// + /// If the address different between the two pointers is not a multiple of + /// `mem::size_of::<T>()` then the result of the division is rounded towards + /// zero. + /// + /// Though this method is safe for any two pointers, note that its result + /// will be mostly useless if the two pointers aren't into the same allocated + /// object, for example if they point to two different local variables. + /// + /// # Panics + /// + /// This function panics if `T` is a zero-sized type. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(ptr_wrapping_offset_from)] + /// + /// let a = [0; 5]; + /// let ptr1: *const i32 = &a[1]; + /// let ptr2: *const i32 = &a[3]; + /// assert_eq!(ptr2.wrapping_offset_from(ptr1), 2); + /// assert_eq!(ptr1.wrapping_offset_from(ptr2), -2); + /// assert_eq!(ptr1.wrapping_offset(2), ptr2); + /// assert_eq!(ptr2.wrapping_offset(-2), ptr1); + /// + /// let ptr1: *const i32 = 3 as _; + /// let ptr2: *const i32 = 13 as _; + /// assert_eq!(ptr2.wrapping_offset_from(ptr1), 2); + /// ``` + #[unstable(feature = "ptr_wrapping_offset_from", issue = "41079")] + #[inline] + pub fn wrapping_offset_from(self, origin: *const T) -> isize + where + T: Sized, + { + let pointee_size = mem::size_of::<T>(); + assert!(0 < pointee_size && pointee_size <= isize::max_value() as usize); + + let d = isize::wrapping_sub(self as _, origin as _); + d.wrapping_div(pointee_size as _) + } + + /// Calculates the offset from a pointer (convenience for `.offset(count as isize)`). + /// + /// `count` is in units of T; e.g., a `count` of 3 represents a pointer + /// offset of `3 * size_of::<T>()` bytes. + /// + /// # Safety + /// + /// If any of the following conditions are violated, the result is Undefined + /// Behavior: + /// + /// * Both the starting and resulting pointer must be either in bounds or one + /// byte past the end of the same allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// * The computed offset, **in bytes**, cannot overflow an `isize`. + /// + /// * The offset being in bounds cannot rely on "wrapping around" the address + /// space. That is, the infinite-precision sum must fit in a `usize`. + /// + /// The compiler and standard library generally tries to ensure allocations + /// never reach a size where an offset is a concern. For instance, `Vec` + /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so + /// `vec.as_ptr().add(vec.len())` is always safe. + /// + /// Most platforms fundamentally can't even construct such an allocation. + /// For instance, no known 64-bit platform can ever serve a request + /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. + /// However, some 32-bit and 16-bit platforms may successfully serve a request for + /// more than `isize::MAX` bytes with things like Physical Address + /// Extension. As such, memory acquired directly from allocators or memory + /// mapped files *may* be too large to handle with this function. + /// + /// Consider using [`wrapping_add`] instead if these constraints are + /// difficult to satisfy. The only advantage of this method is that it + /// enables more aggressive compiler optimizations. + /// + /// [`wrapping_add`]: #method.wrapping_add + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// let s: &str = "123"; + /// let ptr: *const u8 = s.as_ptr(); + /// + /// unsafe { + /// println!("{}", *ptr.add(1) as char); + /// println!("{}", *ptr.add(2) as char); + /// } + /// ``` + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn add(self, count: usize) -> Self + where + T: Sized, + { + self.offset(count as isize) + } + + /// Calculates the offset from a pointer (convenience for + /// `.offset((count as isize).wrapping_neg())`). + /// + /// `count` is in units of T; e.g., a `count` of 3 represents a pointer + /// offset of `3 * size_of::<T>()` bytes. + /// + /// # Safety + /// + /// If any of the following conditions are violated, the result is Undefined + /// Behavior: + /// + /// * Both the starting and resulting pointer must be either in bounds or one + /// byte past the end of the same allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// * The computed offset cannot exceed `isize::MAX` **bytes**. + /// + /// * The offset being in bounds cannot rely on "wrapping around" the address + /// space. That is, the infinite-precision sum must fit in a usize. + /// + /// The compiler and standard library generally tries to ensure allocations + /// never reach a size where an offset is a concern. For instance, `Vec` + /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so + /// `vec.as_ptr().add(vec.len()).sub(vec.len())` is always safe. + /// + /// Most platforms fundamentally can't even construct such an allocation. + /// For instance, no known 64-bit platform can ever serve a request + /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. + /// However, some 32-bit and 16-bit platforms may successfully serve a request for + /// more than `isize::MAX` bytes with things like Physical Address + /// Extension. As such, memory acquired directly from allocators or memory + /// mapped files *may* be too large to handle with this function. + /// + /// Consider using [`wrapping_sub`] instead if these constraints are + /// difficult to satisfy. The only advantage of this method is that it + /// enables more aggressive compiler optimizations. + /// + /// [`wrapping_sub`]: #method.wrapping_sub + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// let s: &str = "123"; + /// + /// unsafe { + /// let end: *const u8 = s.as_ptr().add(3); + /// println!("{}", *end.sub(1) as char); + /// println!("{}", *end.sub(2) as char); + /// } + /// ``` + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn sub(self, count: usize) -> Self + where + T: Sized, + { + self.offset((count as isize).wrapping_neg()) + } + + /// Calculates the offset from a pointer using wrapping arithmetic. + /// (convenience for `.wrapping_offset(count as isize)`) + /// + /// `count` is in units of T; e.g., a `count` of 3 represents a pointer + /// offset of `3 * size_of::<T>()` bytes. + /// + /// # Safety + /// + /// The resulting pointer does not need to be in bounds, but it is + /// potentially hazardous to dereference (which requires `unsafe`). + /// + /// In particular, the resulting pointer remains attached to the same allocated + /// object that `self` points to. It may *not* be used to access a + /// different allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// Compared to [`add`], this method basically delays the requirement of staying + /// within the same allocated object: [`add`] is immediate Undefined Behavior when + /// crossing object boundaries; `wrapping_add` produces a pointer but still leads + /// to Undefined Behavior if that pointer is dereferenced. [`add`] can be optimized + /// better and is thus preferrable in performance-sensitive code. + /// + /// If you need to cross object boundaries, cast the pointer to an integer and + /// do the arithmetic there. + /// + /// [`add`]: #method.add + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// // Iterate using a raw pointer in increments of two elements + /// let data = [1u8, 2, 3, 4, 5]; + /// let mut ptr: *const u8 = data.as_ptr(); + /// let step = 2; + /// let end_rounded_up = ptr.wrapping_add(6); + /// + /// // This loop prints "1, 3, 5, " + /// while ptr != end_rounded_up { + /// unsafe { + /// print!("{}, ", *ptr); + /// } + /// ptr = ptr.wrapping_add(step); + /// } + /// ``` + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub fn wrapping_add(self, count: usize) -> Self + where + T: Sized, + { + self.wrapping_offset(count as isize) + } + + /// Calculates the offset from a pointer using wrapping arithmetic. + /// (convenience for `.wrapping_offset((count as isize).wrapping_sub())`) + /// + /// `count` is in units of T; e.g., a `count` of 3 represents a pointer + /// offset of `3 * size_of::<T>()` bytes. + /// + /// # Safety + /// + /// The resulting pointer does not need to be in bounds, but it is + /// potentially hazardous to dereference (which requires `unsafe`). + /// + /// In particular, the resulting pointer remains attached to the same allocated + /// object that `self` points to. It may *not* be used to access a + /// different allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// Compared to [`sub`], this method basically delays the requirement of staying + /// within the same allocated object: [`sub`] is immediate Undefined Behavior when + /// crossing object boundaries; `wrapping_sub` produces a pointer but still leads + /// to Undefined Behavior if that pointer is dereferenced. [`sub`] can be optimized + /// better and is thus preferrable in performance-sensitive code. + /// + /// If you need to cross object boundaries, cast the pointer to an integer and + /// do the arithmetic there. + /// + /// [`sub`]: #method.sub + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// // Iterate using a raw pointer in increments of two elements (backwards) + /// let data = [1u8, 2, 3, 4, 5]; + /// let mut ptr: *const u8 = data.as_ptr(); + /// let start_rounded_down = ptr.wrapping_sub(2); + /// ptr = ptr.wrapping_add(4); + /// let step = 2; + /// // This loop prints "5, 3, 1, " + /// while ptr != start_rounded_down { + /// unsafe { + /// print!("{}, ", *ptr); + /// } + /// ptr = ptr.wrapping_sub(step); + /// } + /// ``` + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub fn wrapping_sub(self, count: usize) -> Self + where + T: Sized, + { + self.wrapping_offset((count as isize).wrapping_neg()) + } + + /// Reads the value from `self` without moving it. This leaves the + /// memory in `self` unchanged. + /// + /// See [`ptr::read`] for safety concerns and examples. + /// + /// [`ptr::read`]: ./ptr/fn.read.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn read(self) -> T + where + T: Sized, + { + read(self) + } + + /// Performs a volatile read of the value from `self` without moving it. This + /// leaves the memory in `self` unchanged. + /// + /// Volatile operations are intended to act on I/O memory, and are guaranteed + /// to not be elided or reordered by the compiler across other volatile + /// operations. + /// + /// See [`ptr::read_volatile`] for safety concerns and examples. + /// + /// [`ptr::read_volatile`]: ./ptr/fn.read_volatile.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn read_volatile(self) -> T + where + T: Sized, + { + read_volatile(self) + } + + /// Reads the value from `self` without moving it. This leaves the + /// memory in `self` unchanged. + /// + /// Unlike `read`, the pointer may be unaligned. + /// + /// See [`ptr::read_unaligned`] for safety concerns and examples. + /// + /// [`ptr::read_unaligned`]: ./ptr/fn.read_unaligned.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn read_unaligned(self) -> T + where + T: Sized, + { + read_unaligned(self) + } + + /// Copies `count * size_of<T>` bytes from `self` to `dest`. The source + /// and destination may overlap. + /// + /// NOTE: this has the *same* argument order as [`ptr::copy`]. + /// + /// See [`ptr::copy`] for safety concerns and examples. + /// + /// [`ptr::copy`]: ./ptr/fn.copy.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn copy_to(self, dest: *mut T, count: usize) + where + T: Sized, + { + copy(self, dest, count) + } + + /// Copies `count * size_of<T>` bytes from `self` to `dest`. The source + /// and destination may *not* overlap. + /// + /// NOTE: this has the *same* argument order as [`ptr::copy_nonoverlapping`]. + /// + /// See [`ptr::copy_nonoverlapping`] for safety concerns and examples. + /// + /// [`ptr::copy_nonoverlapping`]: ./ptr/fn.copy_nonoverlapping.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn copy_to_nonoverlapping(self, dest: *mut T, count: usize) + where + T: Sized, + { + copy_nonoverlapping(self, dest, count) + } + + /// Computes the offset that needs to be applied to the pointer in order to make it aligned to + /// `align`. + /// + /// If it is not possible to align the pointer, the implementation returns + /// `usize::max_value()`. It is permissible for the implementation to *always* + /// return `usize::max_value()`. Only your algorithm's performance can depend + /// on getting a usable offset here, not its correctness. + /// + /// The offset is expressed in number of `T` elements, and not bytes. The value returned can be + /// used with the `wrapping_add` method. + /// + /// There are no guarantees whatsoever that offsetting the pointer will not overflow or go + /// beyond the allocation that the pointer points into. It is up to the caller to ensure that + /// the returned offset is correct in all terms other than alignment. + /// + /// # Panics + /// + /// The function panics if `align` is not a power-of-two. + /// + /// # Examples + /// + /// Accessing adjacent `u8` as `u16` + /// + /// ``` + /// # fn foo(n: usize) { + /// # use std::mem::align_of; + /// # unsafe { + /// let x = [5u8, 6u8, 7u8, 8u8, 9u8]; + /// let ptr = &x[n] as *const u8; + /// let offset = ptr.align_offset(align_of::<u16>()); + /// if offset < x.len() - n - 1 { + /// let u16_ptr = ptr.add(offset) as *const u16; + /// assert_ne!(*u16_ptr, 500); + /// } else { + /// // while the pointer can be aligned via `offset`, it would point + /// // outside the allocation + /// } + /// # } } + /// ``` + #[stable(feature = "align_offset", since = "1.36.0")] + pub fn align_offset(self, align: usize) -> usize + where + T: Sized, + { + if !align.is_power_of_two() { + panic!("align_offset: align is not a power-of-two"); + } + unsafe { align_offset(self, align) } + } +} + +// Equality for pointers +#[stable(feature = "rust1", since = "1.0.0")] +impl<T: ?Sized> PartialEq for *const T { + #[inline] + fn eq(&self, other: &*const T) -> bool { *self == *other } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl<T: ?Sized> Eq for *const T {} + +// Comparison for pointers +#[stable(feature = "rust1", since = "1.0.0")] +impl<T: ?Sized> Ord for *const T { + #[inline] + fn cmp(&self, other: &*const T) -> Ordering { + if self < other { + Less + } else if self == other { + Equal + } else { + Greater + } + } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl<T: ?Sized> PartialOrd for *const T { + #[inline] + fn partial_cmp(&self, other: &*const T) -> Option<Ordering> { + Some(self.cmp(other)) + } + + #[inline] + fn lt(&self, other: &*const T) -> bool { *self < *other } + + #[inline] + fn le(&self, other: &*const T) -> bool { *self <= *other } + + #[inline] + fn gt(&self, other: &*const T) -> bool { *self > *other } + + #[inline] + fn ge(&self, other: &*const T) -> bool { *self >= *other } +} diff --git a/src/libcore/ptr/mod.rs b/src/libcore/ptr/mod.rs index 776165e7bd7..a3a73ff6c6c 100644 --- a/src/libcore/ptr/mod.rs +++ b/src/libcore/ptr/mod.rs @@ -65,16 +65,15 @@ //! [`write_volatile`]: ./fn.write_volatile.html //! [`NonNull::dangling`]: ./struct.NonNull.html#method.dangling -// ignore-tidy-filelength // ignore-tidy-undocumented-unsafe #![stable(feature = "rust1", since = "1.0.0")] -use crate::cmp::Ordering::{self, Equal, Greater, Less}; +use crate::intrinsics; use crate::fmt; use crate::hash; -use crate::intrinsics; use crate::mem::{self, MaybeUninit}; +use crate::cmp::Ordering; #[stable(feature = "rust1", since = "1.0.0")] pub use crate::intrinsics::copy_nonoverlapping; @@ -93,6 +92,9 @@ mod unique; #[unstable(feature = "ptr_internals", issue = "0")] pub use unique::Unique; +mod const_ptr; +mod mut_ptr; + /// Executes the destructor (if any) of the pointed-to value. /// /// This is semantically equivalent to calling [`ptr::read`] and discarding @@ -1034,1586 +1036,6 @@ pub unsafe fn write_volatile<T>(dst: *mut T, src: T) { intrinsics::volatile_store(dst, src); } -#[lang = "const_ptr"] -impl<T: ?Sized> *const T { - /// Returns `true` if the pointer is null. - /// - /// Note that unsized types have many possible null pointers, as only the - /// raw data pointer is considered, not their length, vtable, etc. - /// Therefore, two pointers that are null may still not compare equal to - /// each other. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// let s: &str = "Follow the rabbit"; - /// let ptr: *const u8 = s.as_ptr(); - /// assert!(!ptr.is_null()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - #[inline] - pub fn is_null(self) -> bool { - // Compare via a cast to a thin pointer, so fat pointers are only - // considering their "data" part for null-ness. - (self as *const u8) == null() - } - - /// Casts to a pointer of another type. - #[stable(feature = "ptr_cast", since = "1.38.0")] - #[rustc_const_stable(feature = "const_ptr_cast", since = "1.38.0")] - #[inline] - pub const fn cast<U>(self) -> *const U { - self as _ - } - - /// Returns `None` if the pointer is null, or else returns a reference to - /// the value wrapped in `Some`. - /// - /// # Safety - /// - /// While this method and its mutable counterpart are useful for - /// null-safety, it is important to note that this is still an unsafe - /// operation because the returned value could be pointing to invalid - /// memory. - /// - /// When calling this method, you have to ensure that *either* the pointer is NULL *or* - /// all of the following is true: - /// - it is properly aligned - /// - it must point to an initialized instance of T; in particular, the pointer must be - /// "dereferencable" in the sense defined [here]. - /// - /// This applies even if the result of this method is unused! - /// (The part about being initialized is not yet fully decided, but until - /// it is, the only safe approach is to ensure that they are indeed initialized.) - /// - /// Additionally, the lifetime `'a` returned is arbitrarily chosen and does - /// not necessarily reflect the actual lifetime of the data. *You* must enforce - /// Rust's aliasing rules. In particular, for the duration of this lifetime, - /// the memory the pointer points to must not get mutated (except inside `UnsafeCell`). - /// - /// [here]: crate::ptr#safety - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// let ptr: *const u8 = &10u8 as *const u8; - /// - /// unsafe { - /// if let Some(val_back) = ptr.as_ref() { - /// println!("We got back the value: {}!", val_back); - /// } - /// } - /// ``` - /// - /// # Null-unchecked version - /// - /// If you are sure the pointer can never be null and are looking for some kind of - /// `as_ref_unchecked` that returns the `&T` instead of `Option<&T>`, know that you can - /// dereference the pointer directly. - /// - /// ``` - /// let ptr: *const u8 = &10u8 as *const u8; - /// - /// unsafe { - /// let val_back = &*ptr; - /// println!("We got back the value: {}!", val_back); - /// } - /// ``` - #[stable(feature = "ptr_as_ref", since = "1.9.0")] - #[inline] - pub unsafe fn as_ref<'a>(self) -> Option<&'a T> { - if self.is_null() { None } else { Some(&*self) } - } - - /// Calculates the offset from a pointer. - /// - /// `count` is in units of T; e.g., a `count` of 3 represents a pointer - /// offset of `3 * size_of::<T>()` bytes. - /// - /// # Safety - /// - /// If any of the following conditions are violated, the result is Undefined - /// Behavior: - /// - /// * Both the starting and resulting pointer must be either in bounds or one - /// byte past the end of the same allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// * The computed offset, **in bytes**, cannot overflow an `isize`. - /// - /// * The offset being in bounds cannot rely on "wrapping around" the address - /// space. That is, the infinite-precision sum, **in bytes** must fit in a usize. - /// - /// The compiler and standard library generally tries to ensure allocations - /// never reach a size where an offset is a concern. For instance, `Vec` - /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so - /// `vec.as_ptr().add(vec.len())` is always safe. - /// - /// Most platforms fundamentally can't even construct such an allocation. - /// For instance, no known 64-bit platform can ever serve a request - /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. - /// However, some 32-bit and 16-bit platforms may successfully serve a request for - /// more than `isize::MAX` bytes with things like Physical Address - /// Extension. As such, memory acquired directly from allocators or memory - /// mapped files *may* be too large to handle with this function. - /// - /// Consider using [`wrapping_offset`] instead if these constraints are - /// difficult to satisfy. The only advantage of this method is that it - /// enables more aggressive compiler optimizations. - /// - /// [`wrapping_offset`]: #method.wrapping_offset - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// let s: &str = "123"; - /// let ptr: *const u8 = s.as_ptr(); - /// - /// unsafe { - /// println!("{}", *ptr.offset(1) as char); - /// println!("{}", *ptr.offset(2) as char); - /// } - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - #[inline] - pub unsafe fn offset(self, count: isize) -> *const T - where - T: Sized, - { - intrinsics::offset(self, count) - } - - /// Calculates the offset from a pointer using wrapping arithmetic. - /// - /// `count` is in units of T; e.g., a `count` of 3 represents a pointer - /// offset of `3 * size_of::<T>()` bytes. - /// - /// # Safety - /// - /// The resulting pointer does not need to be in bounds, but it is - /// potentially hazardous to dereference (which requires `unsafe`). - /// - /// In particular, the resulting pointer remains attached to the same allocated - /// object that `self` points to. It may *not* be used to access a - /// different allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// In other words, `x.wrapping_offset(y.wrapping_offset_from(x))` is - /// *not* the same as `y`, and dereferencing it is undefined behavior - /// unless `x` and `y` point into the same allocated object. - /// - /// Compared to [`offset`], this method basically delays the requirement of staying - /// within the same allocated object: [`offset`] is immediate Undefined Behavior when - /// crossing object boundaries; `wrapping_offset` produces a pointer but still leads - /// to Undefined Behavior if that pointer is dereferenced. [`offset`] can be optimized - /// better and is thus preferrable in performance-sensitive code. - /// - /// If you need to cross object boundaries, cast the pointer to an integer and - /// do the arithmetic there. - /// - /// [`offset`]: #method.offset - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// // Iterate using a raw pointer in increments of two elements - /// let data = [1u8, 2, 3, 4, 5]; - /// let mut ptr: *const u8 = data.as_ptr(); - /// let step = 2; - /// let end_rounded_up = ptr.wrapping_offset(6); - /// - /// // This loop prints "1, 3, 5, " - /// while ptr != end_rounded_up { - /// unsafe { - /// print!("{}, ", *ptr); - /// } - /// ptr = ptr.wrapping_offset(step); - /// } - /// ``` - #[stable(feature = "ptr_wrapping_offset", since = "1.16.0")] - #[inline] - pub fn wrapping_offset(self, count: isize) -> *const T - where - T: Sized, - { - unsafe { intrinsics::arith_offset(self, count) } - } - - /// Calculates the distance between two pointers. The returned value is in - /// units of T: the distance in bytes is divided by `mem::size_of::<T>()`. - /// - /// This function is the inverse of [`offset`]. - /// - /// [`offset`]: #method.offset - /// [`wrapping_offset_from`]: #method.wrapping_offset_from - /// - /// # Safety - /// - /// If any of the following conditions are violated, the result is Undefined - /// Behavior: - /// - /// * Both the starting and other pointer must be either in bounds or one - /// byte past the end of the same allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// * The distance between the pointers, **in bytes**, cannot overflow an `isize`. - /// - /// * The distance between the pointers, in bytes, must be an exact multiple - /// of the size of `T`. - /// - /// * The distance being in bounds cannot rely on "wrapping around" the address space. - /// - /// The compiler and standard library generally try to ensure allocations - /// never reach a size where an offset is a concern. For instance, `Vec` - /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so - /// `ptr_into_vec.offset_from(vec.as_ptr())` is always safe. - /// - /// Most platforms fundamentally can't even construct such an allocation. - /// For instance, no known 64-bit platform can ever serve a request - /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. - /// However, some 32-bit and 16-bit platforms may successfully serve a request for - /// more than `isize::MAX` bytes with things like Physical Address - /// Extension. As such, memory acquired directly from allocators or memory - /// mapped files *may* be too large to handle with this function. - /// - /// Consider using [`wrapping_offset_from`] instead if these constraints are - /// difficult to satisfy. The only advantage of this method is that it - /// enables more aggressive compiler optimizations. - /// - /// # Panics - /// - /// This function panics if `T` is a Zero-Sized Type ("ZST"). - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// #![feature(ptr_offset_from)] - /// - /// let a = [0; 5]; - /// let ptr1: *const i32 = &a[1]; - /// let ptr2: *const i32 = &a[3]; - /// unsafe { - /// assert_eq!(ptr2.offset_from(ptr1), 2); - /// assert_eq!(ptr1.offset_from(ptr2), -2); - /// assert_eq!(ptr1.offset(2), ptr2); - /// assert_eq!(ptr2.offset(-2), ptr1); - /// } - /// ``` - #[unstable(feature = "ptr_offset_from", issue = "41079")] - #[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "41079")] - #[inline] - pub const unsafe fn offset_from(self, origin: *const T) -> isize - where - T: Sized, - { - let pointee_size = mem::size_of::<T>(); - let ok = 0 < pointee_size && pointee_size <= isize::max_value() as usize; - // assert that the pointee size is valid in a const eval compatible way - // FIXME: do this with a real assert at some point - [()][(!ok) as usize]; - intrinsics::ptr_offset_from(self, origin) - } - - /// Calculates the distance between two pointers. The returned value is in - /// units of T: the distance in bytes is divided by `mem::size_of::<T>()`. - /// - /// If the address different between the two pointers is not a multiple of - /// `mem::size_of::<T>()` then the result of the division is rounded towards - /// zero. - /// - /// Though this method is safe for any two pointers, note that its result - /// will be mostly useless if the two pointers aren't into the same allocated - /// object, for example if they point to two different local variables. - /// - /// # Panics - /// - /// This function panics if `T` is a zero-sized type. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// #![feature(ptr_wrapping_offset_from)] - /// - /// let a = [0; 5]; - /// let ptr1: *const i32 = &a[1]; - /// let ptr2: *const i32 = &a[3]; - /// assert_eq!(ptr2.wrapping_offset_from(ptr1), 2); - /// assert_eq!(ptr1.wrapping_offset_from(ptr2), -2); - /// assert_eq!(ptr1.wrapping_offset(2), ptr2); - /// assert_eq!(ptr2.wrapping_offset(-2), ptr1); - /// - /// let ptr1: *const i32 = 3 as _; - /// let ptr2: *const i32 = 13 as _; - /// assert_eq!(ptr2.wrapping_offset_from(ptr1), 2); - /// ``` - #[unstable(feature = "ptr_wrapping_offset_from", issue = "41079")] - #[inline] - pub fn wrapping_offset_from(self, origin: *const T) -> isize - where - T: Sized, - { - let pointee_size = mem::size_of::<T>(); - assert!(0 < pointee_size && pointee_size <= isize::max_value() as usize); - - let d = isize::wrapping_sub(self as _, origin as _); - d.wrapping_div(pointee_size as _) - } - - /// Calculates the offset from a pointer (convenience for `.offset(count as isize)`). - /// - /// `count` is in units of T; e.g., a `count` of 3 represents a pointer - /// offset of `3 * size_of::<T>()` bytes. - /// - /// # Safety - /// - /// If any of the following conditions are violated, the result is Undefined - /// Behavior: - /// - /// * Both the starting and resulting pointer must be either in bounds or one - /// byte past the end of the same allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// * The computed offset, **in bytes**, cannot overflow an `isize`. - /// - /// * The offset being in bounds cannot rely on "wrapping around" the address - /// space. That is, the infinite-precision sum must fit in a `usize`. - /// - /// The compiler and standard library generally tries to ensure allocations - /// never reach a size where an offset is a concern. For instance, `Vec` - /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so - /// `vec.as_ptr().add(vec.len())` is always safe. - /// - /// Most platforms fundamentally can't even construct such an allocation. - /// For instance, no known 64-bit platform can ever serve a request - /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. - /// However, some 32-bit and 16-bit platforms may successfully serve a request for - /// more than `isize::MAX` bytes with things like Physical Address - /// Extension. As such, memory acquired directly from allocators or memory - /// mapped files *may* be too large to handle with this function. - /// - /// Consider using [`wrapping_add`] instead if these constraints are - /// difficult to satisfy. The only advantage of this method is that it - /// enables more aggressive compiler optimizations. - /// - /// [`wrapping_add`]: #method.wrapping_add - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// let s: &str = "123"; - /// let ptr: *const u8 = s.as_ptr(); - /// - /// unsafe { - /// println!("{}", *ptr.add(1) as char); - /// println!("{}", *ptr.add(2) as char); - /// } - /// ``` - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn add(self, count: usize) -> Self - where - T: Sized, - { - self.offset(count as isize) - } - - /// Calculates the offset from a pointer (convenience for - /// `.offset((count as isize).wrapping_neg())`). - /// - /// `count` is in units of T; e.g., a `count` of 3 represents a pointer - /// offset of `3 * size_of::<T>()` bytes. - /// - /// # Safety - /// - /// If any of the following conditions are violated, the result is Undefined - /// Behavior: - /// - /// * Both the starting and resulting pointer must be either in bounds or one - /// byte past the end of the same allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// * The computed offset cannot exceed `isize::MAX` **bytes**. - /// - /// * The offset being in bounds cannot rely on "wrapping around" the address - /// space. That is, the infinite-precision sum must fit in a usize. - /// - /// The compiler and standard library generally tries to ensure allocations - /// never reach a size where an offset is a concern. For instance, `Vec` - /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so - /// `vec.as_ptr().add(vec.len()).sub(vec.len())` is always safe. - /// - /// Most platforms fundamentally can't even construct such an allocation. - /// For instance, no known 64-bit platform can ever serve a request - /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. - /// However, some 32-bit and 16-bit platforms may successfully serve a request for - /// more than `isize::MAX` bytes with things like Physical Address - /// Extension. As such, memory acquired directly from allocators or memory - /// mapped files *may* be too large to handle with this function. - /// - /// Consider using [`wrapping_sub`] instead if these constraints are - /// difficult to satisfy. The only advantage of this method is that it - /// enables more aggressive compiler optimizations. - /// - /// [`wrapping_sub`]: #method.wrapping_sub - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// let s: &str = "123"; - /// - /// unsafe { - /// let end: *const u8 = s.as_ptr().add(3); - /// println!("{}", *end.sub(1) as char); - /// println!("{}", *end.sub(2) as char); - /// } - /// ``` - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn sub(self, count: usize) -> Self - where - T: Sized, - { - self.offset((count as isize).wrapping_neg()) - } - - /// Calculates the offset from a pointer using wrapping arithmetic. - /// (convenience for `.wrapping_offset(count as isize)`) - /// - /// `count` is in units of T; e.g., a `count` of 3 represents a pointer - /// offset of `3 * size_of::<T>()` bytes. - /// - /// # Safety - /// - /// The resulting pointer does not need to be in bounds, but it is - /// potentially hazardous to dereference (which requires `unsafe`). - /// - /// In particular, the resulting pointer remains attached to the same allocated - /// object that `self` points to. It may *not* be used to access a - /// different allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// Compared to [`add`], this method basically delays the requirement of staying - /// within the same allocated object: [`add`] is immediate Undefined Behavior when - /// crossing object boundaries; `wrapping_add` produces a pointer but still leads - /// to Undefined Behavior if that pointer is dereferenced. [`add`] can be optimized - /// better and is thus preferrable in performance-sensitive code. - /// - /// If you need to cross object boundaries, cast the pointer to an integer and - /// do the arithmetic there. - /// - /// [`add`]: #method.add - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// // Iterate using a raw pointer in increments of two elements - /// let data = [1u8, 2, 3, 4, 5]; - /// let mut ptr: *const u8 = data.as_ptr(); - /// let step = 2; - /// let end_rounded_up = ptr.wrapping_add(6); - /// - /// // This loop prints "1, 3, 5, " - /// while ptr != end_rounded_up { - /// unsafe { - /// print!("{}, ", *ptr); - /// } - /// ptr = ptr.wrapping_add(step); - /// } - /// ``` - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub fn wrapping_add(self, count: usize) -> Self - where - T: Sized, - { - self.wrapping_offset(count as isize) - } - - /// Calculates the offset from a pointer using wrapping arithmetic. - /// (convenience for `.wrapping_offset((count as isize).wrapping_sub())`) - /// - /// `count` is in units of T; e.g., a `count` of 3 represents a pointer - /// offset of `3 * size_of::<T>()` bytes. - /// - /// # Safety - /// - /// The resulting pointer does not need to be in bounds, but it is - /// potentially hazardous to dereference (which requires `unsafe`). - /// - /// In particular, the resulting pointer remains attached to the same allocated - /// object that `self` points to. It may *not* be used to access a - /// different allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// Compared to [`sub`], this method basically delays the requirement of staying - /// within the same allocated object: [`sub`] is immediate Undefined Behavior when - /// crossing object boundaries; `wrapping_sub` produces a pointer but still leads - /// to Undefined Behavior if that pointer is dereferenced. [`sub`] can be optimized - /// better and is thus preferrable in performance-sensitive code. - /// - /// If you need to cross object boundaries, cast the pointer to an integer and - /// do the arithmetic there. - /// - /// [`sub`]: #method.sub - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// // Iterate using a raw pointer in increments of two elements (backwards) - /// let data = [1u8, 2, 3, 4, 5]; - /// let mut ptr: *const u8 = data.as_ptr(); - /// let start_rounded_down = ptr.wrapping_sub(2); - /// ptr = ptr.wrapping_add(4); - /// let step = 2; - /// // This loop prints "5, 3, 1, " - /// while ptr != start_rounded_down { - /// unsafe { - /// print!("{}, ", *ptr); - /// } - /// ptr = ptr.wrapping_sub(step); - /// } - /// ``` - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub fn wrapping_sub(self, count: usize) -> Self - where - T: Sized, - { - self.wrapping_offset((count as isize).wrapping_neg()) - } - - /// Reads the value from `self` without moving it. This leaves the - /// memory in `self` unchanged. - /// - /// See [`ptr::read`] for safety concerns and examples. - /// - /// [`ptr::read`]: ./ptr/fn.read.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn read(self) -> T - where - T: Sized, - { - read(self) - } - - /// Performs a volatile read of the value from `self` without moving it. This - /// leaves the memory in `self` unchanged. - /// - /// Volatile operations are intended to act on I/O memory, and are guaranteed - /// to not be elided or reordered by the compiler across other volatile - /// operations. - /// - /// See [`ptr::read_volatile`] for safety concerns and examples. - /// - /// [`ptr::read_volatile`]: ./ptr/fn.read_volatile.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn read_volatile(self) -> T - where - T: Sized, - { - read_volatile(self) - } - - /// Reads the value from `self` without moving it. This leaves the - /// memory in `self` unchanged. - /// - /// Unlike `read`, the pointer may be unaligned. - /// - /// See [`ptr::read_unaligned`] for safety concerns and examples. - /// - /// [`ptr::read_unaligned`]: ./ptr/fn.read_unaligned.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn read_unaligned(self) -> T - where - T: Sized, - { - read_unaligned(self) - } - - /// Copies `count * size_of<T>` bytes from `self` to `dest`. The source - /// and destination may overlap. - /// - /// NOTE: this has the *same* argument order as [`ptr::copy`]. - /// - /// See [`ptr::copy`] for safety concerns and examples. - /// - /// [`ptr::copy`]: ./ptr/fn.copy.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn copy_to(self, dest: *mut T, count: usize) - where - T: Sized, - { - copy(self, dest, count) - } - - /// Copies `count * size_of<T>` bytes from `self` to `dest`. The source - /// and destination may *not* overlap. - /// - /// NOTE: this has the *same* argument order as [`ptr::copy_nonoverlapping`]. - /// - /// See [`ptr::copy_nonoverlapping`] for safety concerns and examples. - /// - /// [`ptr::copy_nonoverlapping`]: ./ptr/fn.copy_nonoverlapping.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn copy_to_nonoverlapping(self, dest: *mut T, count: usize) - where - T: Sized, - { - copy_nonoverlapping(self, dest, count) - } - - /// Computes the offset that needs to be applied to the pointer in order to make it aligned to - /// `align`. - /// - /// If it is not possible to align the pointer, the implementation returns - /// `usize::max_value()`. It is permissible for the implementation to *always* - /// return `usize::max_value()`. Only your algorithm's performance can depend - /// on getting a usable offset here, not its correctness. - /// - /// The offset is expressed in number of `T` elements, and not bytes. The value returned can be - /// used with the `wrapping_add` method. - /// - /// There are no guarantees whatsoever that offsetting the pointer will not overflow or go - /// beyond the allocation that the pointer points into. It is up to the caller to ensure that - /// the returned offset is correct in all terms other than alignment. - /// - /// # Panics - /// - /// The function panics if `align` is not a power-of-two. - /// - /// # Examples - /// - /// Accessing adjacent `u8` as `u16` - /// - /// ``` - /// # fn foo(n: usize) { - /// # use std::mem::align_of; - /// # unsafe { - /// let x = [5u8, 6u8, 7u8, 8u8, 9u8]; - /// let ptr = &x[n] as *const u8; - /// let offset = ptr.align_offset(align_of::<u16>()); - /// if offset < x.len() - n - 1 { - /// let u16_ptr = ptr.add(offset) as *const u16; - /// assert_ne!(*u16_ptr, 500); - /// } else { - /// // while the pointer can be aligned via `offset`, it would point - /// // outside the allocation - /// } - /// # } } - /// ``` - #[stable(feature = "align_offset", since = "1.36.0")] - pub fn align_offset(self, align: usize) -> usize - where - T: Sized, - { - if !align.is_power_of_two() { - panic!("align_offset: align is not a power-of-two"); - } - unsafe { align_offset(self, align) } - } -} - -#[lang = "mut_ptr"] -impl<T: ?Sized> *mut T { - /// Returns `true` if the pointer is null. - /// - /// Note that unsized types have many possible null pointers, as only the - /// raw data pointer is considered, not their length, vtable, etc. - /// Therefore, two pointers that are null may still not compare equal to - /// each other. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// let mut s = [1, 2, 3]; - /// let ptr: *mut u32 = s.as_mut_ptr(); - /// assert!(!ptr.is_null()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - #[inline] - pub fn is_null(self) -> bool { - // Compare via a cast to a thin pointer, so fat pointers are only - // considering their "data" part for null-ness. - (self as *mut u8) == null_mut() - } - - /// Casts to a pointer of another type. - #[stable(feature = "ptr_cast", since = "1.38.0")] - #[rustc_const_stable(feature = "const_ptr_cast", since = "1.38.0")] - #[inline] - pub const fn cast<U>(self) -> *mut U { - self as _ - } - - /// Returns `None` if the pointer is null, or else returns a reference to - /// the value wrapped in `Some`. - /// - /// # Safety - /// - /// While this method and its mutable counterpart are useful for - /// null-safety, it is important to note that this is still an unsafe - /// operation because the returned value could be pointing to invalid - /// memory. - /// - /// When calling this method, you have to ensure that if the pointer is - /// non-NULL, then it is properly aligned, dereferencable (for the whole - /// size of `T`) and points to an initialized instance of `T`. This applies - /// even if the result of this method is unused! - /// (The part about being initialized is not yet fully decided, but until - /// it is, the only safe approach is to ensure that they are indeed initialized.) - /// - /// Additionally, the lifetime `'a` returned is arbitrarily chosen and does - /// not necessarily reflect the actual lifetime of the data. It is up to the - /// caller to ensure that for the duration of this lifetime, the memory this - /// pointer points to does not get written to outside of `UnsafeCell<U>`. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// let ptr: *mut u8 = &mut 10u8 as *mut u8; - /// - /// unsafe { - /// if let Some(val_back) = ptr.as_ref() { - /// println!("We got back the value: {}!", val_back); - /// } - /// } - /// ``` - /// - /// # Null-unchecked version - /// - /// If you are sure the pointer can never be null and are looking for some kind of - /// `as_ref_unchecked` that returns the `&T` instead of `Option<&T>`, know that you can - /// dereference the pointer directly. - /// - /// ``` - /// let ptr: *mut u8 = &mut 10u8 as *mut u8; - /// - /// unsafe { - /// let val_back = &*ptr; - /// println!("We got back the value: {}!", val_back); - /// } - /// ``` - #[stable(feature = "ptr_as_ref", since = "1.9.0")] - #[inline] - pub unsafe fn as_ref<'a>(self) -> Option<&'a T> { - if self.is_null() { None } else { Some(&*self) } - } - - /// Calculates the offset from a pointer. - /// - /// `count` is in units of T; e.g., a `count` of 3 represents a pointer - /// offset of `3 * size_of::<T>()` bytes. - /// - /// # Safety - /// - /// If any of the following conditions are violated, the result is Undefined - /// Behavior: - /// - /// * Both the starting and resulting pointer must be either in bounds or one - /// byte past the end of the same allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// * The computed offset, **in bytes**, cannot overflow an `isize`. - /// - /// * The offset being in bounds cannot rely on "wrapping around" the address - /// space. That is, the infinite-precision sum, **in bytes** must fit in a usize. - /// - /// The compiler and standard library generally tries to ensure allocations - /// never reach a size where an offset is a concern. For instance, `Vec` - /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so - /// `vec.as_ptr().add(vec.len())` is always safe. - /// - /// Most platforms fundamentally can't even construct such an allocation. - /// For instance, no known 64-bit platform can ever serve a request - /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. - /// However, some 32-bit and 16-bit platforms may successfully serve a request for - /// more than `isize::MAX` bytes with things like Physical Address - /// Extension. As such, memory acquired directly from allocators or memory - /// mapped files *may* be too large to handle with this function. - /// - /// Consider using [`wrapping_offset`] instead if these constraints are - /// difficult to satisfy. The only advantage of this method is that it - /// enables more aggressive compiler optimizations. - /// - /// [`wrapping_offset`]: #method.wrapping_offset - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// let mut s = [1, 2, 3]; - /// let ptr: *mut u32 = s.as_mut_ptr(); - /// - /// unsafe { - /// println!("{}", *ptr.offset(1)); - /// println!("{}", *ptr.offset(2)); - /// } - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - #[inline] - pub unsafe fn offset(self, count: isize) -> *mut T - where - T: Sized, - { - intrinsics::offset(self, count) as *mut T - } - - /// Calculates the offset from a pointer using wrapping arithmetic. - /// `count` is in units of T; e.g., a `count` of 3 represents a pointer - /// offset of `3 * size_of::<T>()` bytes. - /// - /// # Safety - /// - /// The resulting pointer does not need to be in bounds, but it is - /// potentially hazardous to dereference (which requires `unsafe`). - /// - /// In particular, the resulting pointer remains attached to the same allocated - /// object that `self` points to. It may *not* be used to access a - /// different allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// In other words, `x.wrapping_offset(y.wrapping_offset_from(x))` is - /// *not* the same as `y`, and dereferencing it is undefined behavior - /// unless `x` and `y` point into the same allocated object. - /// - /// Compared to [`offset`], this method basically delays the requirement of staying - /// within the same allocated object: [`offset`] is immediate Undefined Behavior when - /// crossing object boundaries; `wrapping_offset` produces a pointer but still leads - /// to Undefined Behavior if that pointer is dereferenced. [`offset`] can be optimized - /// better and is thus preferrable in performance-sensitive code. - /// - /// If you need to cross object boundaries, cast the pointer to an integer and - /// do the arithmetic there. - /// - /// [`offset`]: #method.offset - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// // Iterate using a raw pointer in increments of two elements - /// let mut data = [1u8, 2, 3, 4, 5]; - /// let mut ptr: *mut u8 = data.as_mut_ptr(); - /// let step = 2; - /// let end_rounded_up = ptr.wrapping_offset(6); - /// - /// while ptr != end_rounded_up { - /// unsafe { - /// *ptr = 0; - /// } - /// ptr = ptr.wrapping_offset(step); - /// } - /// assert_eq!(&data, &[0, 2, 0, 4, 0]); - /// ``` - #[stable(feature = "ptr_wrapping_offset", since = "1.16.0")] - #[inline] - pub fn wrapping_offset(self, count: isize) -> *mut T - where - T: Sized, - { - unsafe { intrinsics::arith_offset(self, count) as *mut T } - } - - /// Returns `None` if the pointer is null, or else returns a mutable - /// reference to the value wrapped in `Some`. - /// - /// # Safety - /// - /// As with [`as_ref`], this is unsafe because it cannot verify the validity - /// of the returned pointer, nor can it ensure that the lifetime `'a` - /// returned is indeed a valid lifetime for the contained data. - /// - /// When calling this method, you have to ensure that *either* the pointer is NULL *or* - /// all of the following is true: - /// - it is properly aligned - /// - it must point to an initialized instance of T; in particular, the pointer must be - /// "dereferencable" in the sense defined [here]. - /// - /// This applies even if the result of this method is unused! - /// (The part about being initialized is not yet fully decided, but until - /// it is the only safe approach is to ensure that they are indeed initialized.) - /// - /// Additionally, the lifetime `'a` returned is arbitrarily chosen and does - /// not necessarily reflect the actual lifetime of the data. *You* must enforce - /// Rust's aliasing rules. In particular, for the duration of this lifetime, - /// the memory this pointer points to must not get accessed (read or written) - /// through any other pointer. - /// - /// [here]: crate::ptr#safety - /// [`as_ref`]: #method.as_ref - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// let mut s = [1, 2, 3]; - /// let ptr: *mut u32 = s.as_mut_ptr(); - /// let first_value = unsafe { ptr.as_mut().unwrap() }; - /// *first_value = 4; - /// println!("{:?}", s); // It'll print: "[4, 2, 3]". - /// ``` - #[stable(feature = "ptr_as_ref", since = "1.9.0")] - #[inline] - pub unsafe fn as_mut<'a>(self) -> Option<&'a mut T> { - if self.is_null() { None } else { Some(&mut *self) } - } - - /// Calculates the distance between two pointers. The returned value is in - /// units of T: the distance in bytes is divided by `mem::size_of::<T>()`. - /// - /// This function is the inverse of [`offset`]. - /// - /// [`offset`]: #method.offset-1 - /// [`wrapping_offset_from`]: #method.wrapping_offset_from-1 - /// - /// # Safety - /// - /// If any of the following conditions are violated, the result is Undefined - /// Behavior: - /// - /// * Both the starting and other pointer must be either in bounds or one - /// byte past the end of the same allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// * The distance between the pointers, **in bytes**, cannot overflow an `isize`. - /// - /// * The distance between the pointers, in bytes, must be an exact multiple - /// of the size of `T`. - /// - /// * The distance being in bounds cannot rely on "wrapping around" the address space. - /// - /// The compiler and standard library generally try to ensure allocations - /// never reach a size where an offset is a concern. For instance, `Vec` - /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so - /// `ptr_into_vec.offset_from(vec.as_ptr())` is always safe. - /// - /// Most platforms fundamentally can't even construct such an allocation. - /// For instance, no known 64-bit platform can ever serve a request - /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. - /// However, some 32-bit and 16-bit platforms may successfully serve a request for - /// more than `isize::MAX` bytes with things like Physical Address - /// Extension. As such, memory acquired directly from allocators or memory - /// mapped files *may* be too large to handle with this function. - /// - /// Consider using [`wrapping_offset_from`] instead if these constraints are - /// difficult to satisfy. The only advantage of this method is that it - /// enables more aggressive compiler optimizations. - /// - /// # Panics - /// - /// This function panics if `T` is a Zero-Sized Type ("ZST"). - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// #![feature(ptr_offset_from)] - /// - /// let mut a = [0; 5]; - /// let ptr1: *mut i32 = &mut a[1]; - /// let ptr2: *mut i32 = &mut a[3]; - /// unsafe { - /// assert_eq!(ptr2.offset_from(ptr1), 2); - /// assert_eq!(ptr1.offset_from(ptr2), -2); - /// assert_eq!(ptr1.offset(2), ptr2); - /// assert_eq!(ptr2.offset(-2), ptr1); - /// } - /// ``` - #[unstable(feature = "ptr_offset_from", issue = "41079")] - #[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "41079")] - #[inline] - pub const unsafe fn offset_from(self, origin: *const T) -> isize - where - T: Sized, - { - (self as *const T).offset_from(origin) - } - - /// Calculates the distance between two pointers. The returned value is in - /// units of T: the distance in bytes is divided by `mem::size_of::<T>()`. - /// - /// If the address different between the two pointers is not a multiple of - /// `mem::size_of::<T>()` then the result of the division is rounded towards - /// zero. - /// - /// Though this method is safe for any two pointers, note that its result - /// will be mostly useless if the two pointers aren't into the same allocated - /// object, for example if they point to two different local variables. - /// - /// # Panics - /// - /// This function panics if `T` is a zero-sized type. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// #![feature(ptr_wrapping_offset_from)] - /// - /// let mut a = [0; 5]; - /// let ptr1: *mut i32 = &mut a[1]; - /// let ptr2: *mut i32 = &mut a[3]; - /// assert_eq!(ptr2.wrapping_offset_from(ptr1), 2); - /// assert_eq!(ptr1.wrapping_offset_from(ptr2), -2); - /// assert_eq!(ptr1.wrapping_offset(2), ptr2); - /// assert_eq!(ptr2.wrapping_offset(-2), ptr1); - /// - /// let ptr1: *mut i32 = 3 as _; - /// let ptr2: *mut i32 = 13 as _; - /// assert_eq!(ptr2.wrapping_offset_from(ptr1), 2); - /// ``` - #[unstable(feature = "ptr_wrapping_offset_from", issue = "41079")] - #[inline] - pub fn wrapping_offset_from(self, origin: *const T) -> isize - where - T: Sized, - { - (self as *const T).wrapping_offset_from(origin) - } - - /// Calculates the offset from a pointer (convenience for `.offset(count as isize)`). - /// - /// `count` is in units of T; e.g., a `count` of 3 represents a pointer - /// offset of `3 * size_of::<T>()` bytes. - /// - /// # Safety - /// - /// If any of the following conditions are violated, the result is Undefined - /// Behavior: - /// - /// * Both the starting and resulting pointer must be either in bounds or one - /// byte past the end of the same allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// * The computed offset, **in bytes**, cannot overflow an `isize`. - /// - /// * The offset being in bounds cannot rely on "wrapping around" the address - /// space. That is, the infinite-precision sum must fit in a `usize`. - /// - /// The compiler and standard library generally tries to ensure allocations - /// never reach a size where an offset is a concern. For instance, `Vec` - /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so - /// `vec.as_ptr().add(vec.len())` is always safe. - /// - /// Most platforms fundamentally can't even construct such an allocation. - /// For instance, no known 64-bit platform can ever serve a request - /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. - /// However, some 32-bit and 16-bit platforms may successfully serve a request for - /// more than `isize::MAX` bytes with things like Physical Address - /// Extension. As such, memory acquired directly from allocators or memory - /// mapped files *may* be too large to handle with this function. - /// - /// Consider using [`wrapping_add`] instead if these constraints are - /// difficult to satisfy. The only advantage of this method is that it - /// enables more aggressive compiler optimizations. - /// - /// [`wrapping_add`]: #method.wrapping_add - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// let s: &str = "123"; - /// let ptr: *const u8 = s.as_ptr(); - /// - /// unsafe { - /// println!("{}", *ptr.add(1) as char); - /// println!("{}", *ptr.add(2) as char); - /// } - /// ``` - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn add(self, count: usize) -> Self - where - T: Sized, - { - self.offset(count as isize) - } - - /// Calculates the offset from a pointer (convenience for - /// `.offset((count as isize).wrapping_neg())`). - /// - /// `count` is in units of T; e.g., a `count` of 3 represents a pointer - /// offset of `3 * size_of::<T>()` bytes. - /// - /// # Safety - /// - /// If any of the following conditions are violated, the result is Undefined - /// Behavior: - /// - /// * Both the starting and resulting pointer must be either in bounds or one - /// byte past the end of the same allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// * The computed offset cannot exceed `isize::MAX` **bytes**. - /// - /// * The offset being in bounds cannot rely on "wrapping around" the address - /// space. That is, the infinite-precision sum must fit in a usize. - /// - /// The compiler and standard library generally tries to ensure allocations - /// never reach a size where an offset is a concern. For instance, `Vec` - /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so - /// `vec.as_ptr().add(vec.len()).sub(vec.len())` is always safe. - /// - /// Most platforms fundamentally can't even construct such an allocation. - /// For instance, no known 64-bit platform can ever serve a request - /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. - /// However, some 32-bit and 16-bit platforms may successfully serve a request for - /// more than `isize::MAX` bytes with things like Physical Address - /// Extension. As such, memory acquired directly from allocators or memory - /// mapped files *may* be too large to handle with this function. - /// - /// Consider using [`wrapping_sub`] instead if these constraints are - /// difficult to satisfy. The only advantage of this method is that it - /// enables more aggressive compiler optimizations. - /// - /// [`wrapping_sub`]: #method.wrapping_sub - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// let s: &str = "123"; - /// - /// unsafe { - /// let end: *const u8 = s.as_ptr().add(3); - /// println!("{}", *end.sub(1) as char); - /// println!("{}", *end.sub(2) as char); - /// } - /// ``` - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn sub(self, count: usize) -> Self - where - T: Sized, - { - self.offset((count as isize).wrapping_neg()) - } - - /// Calculates the offset from a pointer using wrapping arithmetic. - /// (convenience for `.wrapping_offset(count as isize)`) - /// - /// `count` is in units of T; e.g., a `count` of 3 represents a pointer - /// offset of `3 * size_of::<T>()` bytes. - /// - /// # Safety - /// - /// The resulting pointer does not need to be in bounds, but it is - /// potentially hazardous to dereference (which requires `unsafe`). - /// - /// In particular, the resulting pointer remains attached to the same allocated - /// object that `self` points to. It may *not* be used to access a - /// different allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// Compared to [`add`], this method basically delays the requirement of staying - /// within the same allocated object: [`add`] is immediate Undefined Behavior when - /// crossing object boundaries; `wrapping_add` produces a pointer but still leads - /// to Undefined Behavior if that pointer is dereferenced. [`add`] can be optimized - /// better and is thus preferrable in performance-sensitive code. - /// - /// If you need to cross object boundaries, cast the pointer to an integer and - /// do the arithmetic there. - /// - /// [`add`]: #method.add - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// // Iterate using a raw pointer in increments of two elements - /// let data = [1u8, 2, 3, 4, 5]; - /// let mut ptr: *const u8 = data.as_ptr(); - /// let step = 2; - /// let end_rounded_up = ptr.wrapping_add(6); - /// - /// // This loop prints "1, 3, 5, " - /// while ptr != end_rounded_up { - /// unsafe { - /// print!("{}, ", *ptr); - /// } - /// ptr = ptr.wrapping_add(step); - /// } - /// ``` - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub fn wrapping_add(self, count: usize) -> Self - where - T: Sized, - { - self.wrapping_offset(count as isize) - } - - /// Calculates the offset from a pointer using wrapping arithmetic. - /// (convenience for `.wrapping_offset((count as isize).wrapping_sub())`) - /// - /// `count` is in units of T; e.g., a `count` of 3 represents a pointer - /// offset of `3 * size_of::<T>()` bytes. - /// - /// # Safety - /// - /// The resulting pointer does not need to be in bounds, but it is - /// potentially hazardous to dereference (which requires `unsafe`). - /// - /// In particular, the resulting pointer remains attached to the same allocated - /// object that `self` points to. It may *not* be used to access a - /// different allocated object. Note that in Rust, - /// every (stack-allocated) variable is considered a separate allocated object. - /// - /// Compared to [`sub`], this method basically delays the requirement of staying - /// within the same allocated object: [`sub`] is immediate Undefined Behavior when - /// crossing object boundaries; `wrapping_sub` produces a pointer but still leads - /// to Undefined Behavior if that pointer is dereferenced. [`sub`] can be optimized - /// better and is thus preferrable in performance-sensitive code. - /// - /// If you need to cross object boundaries, cast the pointer to an integer and - /// do the arithmetic there. - /// - /// [`sub`]: #method.sub - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// // Iterate using a raw pointer in increments of two elements (backwards) - /// let data = [1u8, 2, 3, 4, 5]; - /// let mut ptr: *const u8 = data.as_ptr(); - /// let start_rounded_down = ptr.wrapping_sub(2); - /// ptr = ptr.wrapping_add(4); - /// let step = 2; - /// // This loop prints "5, 3, 1, " - /// while ptr != start_rounded_down { - /// unsafe { - /// print!("{}, ", *ptr); - /// } - /// ptr = ptr.wrapping_sub(step); - /// } - /// ``` - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub fn wrapping_sub(self, count: usize) -> Self - where - T: Sized, - { - self.wrapping_offset((count as isize).wrapping_neg()) - } - - /// Reads the value from `self` without moving it. This leaves the - /// memory in `self` unchanged. - /// - /// See [`ptr::read`] for safety concerns and examples. - /// - /// [`ptr::read`]: ./ptr/fn.read.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn read(self) -> T - where - T: Sized, - { - read(self) - } - - /// Performs a volatile read of the value from `self` without moving it. This - /// leaves the memory in `self` unchanged. - /// - /// Volatile operations are intended to act on I/O memory, and are guaranteed - /// to not be elided or reordered by the compiler across other volatile - /// operations. - /// - /// See [`ptr::read_volatile`] for safety concerns and examples. - /// - /// [`ptr::read_volatile`]: ./ptr/fn.read_volatile.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn read_volatile(self) -> T - where - T: Sized, - { - read_volatile(self) - } - - /// Reads the value from `self` without moving it. This leaves the - /// memory in `self` unchanged. - /// - /// Unlike `read`, the pointer may be unaligned. - /// - /// See [`ptr::read_unaligned`] for safety concerns and examples. - /// - /// [`ptr::read_unaligned`]: ./ptr/fn.read_unaligned.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn read_unaligned(self) -> T - where - T: Sized, - { - read_unaligned(self) - } - - /// Copies `count * size_of<T>` bytes from `self` to `dest`. The source - /// and destination may overlap. - /// - /// NOTE: this has the *same* argument order as [`ptr::copy`]. - /// - /// See [`ptr::copy`] for safety concerns and examples. - /// - /// [`ptr::copy`]: ./ptr/fn.copy.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn copy_to(self, dest: *mut T, count: usize) - where - T: Sized, - { - copy(self, dest, count) - } - - /// Copies `count * size_of<T>` bytes from `self` to `dest`. The source - /// and destination may *not* overlap. - /// - /// NOTE: this has the *same* argument order as [`ptr::copy_nonoverlapping`]. - /// - /// See [`ptr::copy_nonoverlapping`] for safety concerns and examples. - /// - /// [`ptr::copy_nonoverlapping`]: ./ptr/fn.copy_nonoverlapping.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn copy_to_nonoverlapping(self, dest: *mut T, count: usize) - where - T: Sized, - { - copy_nonoverlapping(self, dest, count) - } - - /// Copies `count * size_of<T>` bytes from `src` to `self`. The source - /// and destination may overlap. - /// - /// NOTE: this has the *opposite* argument order of [`ptr::copy`]. - /// - /// See [`ptr::copy`] for safety concerns and examples. - /// - /// [`ptr::copy`]: ./ptr/fn.copy.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn copy_from(self, src: *const T, count: usize) - where - T: Sized, - { - copy(src, self, count) - } - - /// Copies `count * size_of<T>` bytes from `src` to `self`. The source - /// and destination may *not* overlap. - /// - /// NOTE: this has the *opposite* argument order of [`ptr::copy_nonoverlapping`]. - /// - /// See [`ptr::copy_nonoverlapping`] for safety concerns and examples. - /// - /// [`ptr::copy_nonoverlapping`]: ./ptr/fn.copy_nonoverlapping.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn copy_from_nonoverlapping(self, src: *const T, count: usize) - where - T: Sized, - { - copy_nonoverlapping(src, self, count) - } - - /// Executes the destructor (if any) of the pointed-to value. - /// - /// See [`ptr::drop_in_place`] for safety concerns and examples. - /// - /// [`ptr::drop_in_place`]: ./ptr/fn.drop_in_place.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn drop_in_place(self) { - drop_in_place(self) - } - - /// Overwrites a memory location with the given value without reading or - /// dropping the old value. - /// - /// See [`ptr::write`] for safety concerns and examples. - /// - /// [`ptr::write`]: ./ptr/fn.write.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn write(self, val: T) - where - T: Sized, - { - write(self, val) - } - - /// Invokes memset on the specified pointer, setting `count * size_of::<T>()` - /// bytes of memory starting at `self` to `val`. - /// - /// See [`ptr::write_bytes`] for safety concerns and examples. - /// - /// [`ptr::write_bytes`]: ./ptr/fn.write_bytes.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn write_bytes(self, val: u8, count: usize) - where - T: Sized, - { - write_bytes(self, val, count) - } - - /// Performs a volatile write of a memory location with the given value without - /// reading or dropping the old value. - /// - /// Volatile operations are intended to act on I/O memory, and are guaranteed - /// to not be elided or reordered by the compiler across other volatile - /// operations. - /// - /// See [`ptr::write_volatile`] for safety concerns and examples. - /// - /// [`ptr::write_volatile`]: ./ptr/fn.write_volatile.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn write_volatile(self, val: T) - where - T: Sized, - { - write_volatile(self, val) - } - - /// Overwrites a memory location with the given value without reading or - /// dropping the old value. - /// - /// Unlike `write`, the pointer may be unaligned. - /// - /// See [`ptr::write_unaligned`] for safety concerns and examples. - /// - /// [`ptr::write_unaligned`]: ./ptr/fn.write_unaligned.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn write_unaligned(self, val: T) - where - T: Sized, - { - write_unaligned(self, val) - } - - /// Replaces the value at `self` with `src`, returning the old - /// value, without dropping either. - /// - /// See [`ptr::replace`] for safety concerns and examples. - /// - /// [`ptr::replace`]: ./ptr/fn.replace.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn replace(self, src: T) -> T - where - T: Sized, - { - replace(self, src) - } - - /// Swaps the values at two mutable locations of the same type, without - /// deinitializing either. They may overlap, unlike `mem::swap` which is - /// otherwise equivalent. - /// - /// See [`ptr::swap`] for safety concerns and examples. - /// - /// [`ptr::swap`]: ./ptr/fn.swap.html - #[stable(feature = "pointer_methods", since = "1.26.0")] - #[inline] - pub unsafe fn swap(self, with: *mut T) - where - T: Sized, - { - swap(self, with) - } - - /// Computes the offset that needs to be applied to the pointer in order to make it aligned to - /// `align`. - /// - /// If it is not possible to align the pointer, the implementation returns - /// `usize::max_value()`. It is permissible for the implementation to *always* - /// return `usize::max_value()`. Only your algorithm's performance can depend - /// on getting a usable offset here, not its correctness. - /// - /// The offset is expressed in number of `T` elements, and not bytes. The value returned can be - /// used with the `wrapping_add` method. - /// - /// There are no guarantees whatsoever that offsetting the pointer will not overflow or go - /// beyond the allocation that the pointer points into. It is up to the caller to ensure that - /// the returned offset is correct in all terms other than alignment. - /// - /// # Panics - /// - /// The function panics if `align` is not a power-of-two. - /// - /// # Examples - /// - /// Accessing adjacent `u8` as `u16` - /// - /// ``` - /// # fn foo(n: usize) { - /// # use std::mem::align_of; - /// # unsafe { - /// let x = [5u8, 6u8, 7u8, 8u8, 9u8]; - /// let ptr = &x[n] as *const u8; - /// let offset = ptr.align_offset(align_of::<u16>()); - /// if offset < x.len() - n - 1 { - /// let u16_ptr = ptr.add(offset) as *const u16; - /// assert_ne!(*u16_ptr, 500); - /// } else { - /// // while the pointer can be aligned via `offset`, it would point - /// // outside the allocation - /// } - /// # } } - /// ``` - #[stable(feature = "align_offset", since = "1.36.0")] - pub fn align_offset(self, align: usize) -> usize - where - T: Sized, - { - if !align.is_power_of_two() { - panic!("align_offset: align is not a power-of-two"); - } - unsafe { align_offset(self, align) } - } -} - /// Align pointer `p`. /// /// Calculate offset (in terms of elements of `stride` stride) that has to be applied @@ -2728,29 +1150,6 @@ pub(crate) unsafe fn align_offset<T: Sized>(p: *const T, a: usize) -> usize { usize::max_value() } -// Equality for pointers -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: ?Sized> PartialEq for *const T { - #[inline] - fn eq(&self, other: &*const T) -> bool { - *self == *other - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: ?Sized> Eq for *const T {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: ?Sized> PartialEq for *mut T { - #[inline] - fn eq(&self, other: &*mut T) -> bool { - *self == *other - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: ?Sized> Eq for *mut T {} - /// Compares raw pointers for equality. /// /// This is the same as using the `==` operator, but less generic: @@ -2944,88 +1343,3 @@ fnptr_impls_args! { A, B, C, D, E, F, G, H, I } fnptr_impls_args! { A, B, C, D, E, F, G, H, I, J } fnptr_impls_args! { A, B, C, D, E, F, G, H, I, J, K } fnptr_impls_args! { A, B, C, D, E, F, G, H, I, J, K, L } - -// Comparison for pointers -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: ?Sized> Ord for *const T { - #[inline] - fn cmp(&self, other: &*const T) -> Ordering { - if self < other { - Less - } else if self == other { - Equal - } else { - Greater - } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: ?Sized> PartialOrd for *const T { - #[inline] - fn partial_cmp(&self, other: &*const T) -> Option<Ordering> { - Some(self.cmp(other)) - } - - #[inline] - fn lt(&self, other: &*const T) -> bool { - *self < *other - } - - #[inline] - fn le(&self, other: &*const T) -> bool { - *self <= *other - } - - #[inline] - fn gt(&self, other: &*const T) -> bool { - *self > *other - } - - #[inline] - fn ge(&self, other: &*const T) -> bool { - *self >= *other - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: ?Sized> Ord for *mut T { - #[inline] - fn cmp(&self, other: &*mut T) -> Ordering { - if self < other { - Less - } else if self == other { - Equal - } else { - Greater - } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: ?Sized> PartialOrd for *mut T { - #[inline] - fn partial_cmp(&self, other: &*mut T) -> Option<Ordering> { - Some(self.cmp(other)) - } - - #[inline] - fn lt(&self, other: &*mut T) -> bool { - *self < *other - } - - #[inline] - fn le(&self, other: &*mut T) -> bool { - *self <= *other - } - - #[inline] - fn gt(&self, other: &*mut T) -> bool { - *self > *other - } - - #[inline] - fn ge(&self, other: &*mut T) -> bool { - *self >= *other - } -} diff --git a/src/libcore/ptr/mut_ptr.rs b/src/libcore/ptr/mut_ptr.rs new file mode 100644 index 00000000000..fd5decbd7ea --- /dev/null +++ b/src/libcore/ptr/mut_ptr.rs @@ -0,0 +1,925 @@ +use crate::cmp::Ordering::{self, Less, Equal, Greater}; +use crate::intrinsics; +use super::*; + +// ignore-tidy-undocumented-unsafe + +#[lang = "mut_ptr"] +impl<T: ?Sized> *mut T { + /// Returns `true` if the pointer is null. + /// + /// Note that unsized types have many possible null pointers, as only the + /// raw data pointer is considered, not their length, vtable, etc. + /// Therefore, two pointers that are null may still not compare equal to + /// each other. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// let mut s = [1, 2, 3]; + /// let ptr: *mut u32 = s.as_mut_ptr(); + /// assert!(!ptr.is_null()); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[inline] + pub fn is_null(self) -> bool { + // Compare via a cast to a thin pointer, so fat pointers are only + // considering their "data" part for null-ness. + (self as *mut u8) == null_mut() + } + + /// Casts to a pointer of another type. + #[stable(feature = "ptr_cast", since = "1.38.0")] + #[rustc_const_stable(feature = "const_ptr_cast", since = "1.38.0")] + #[inline] + pub const fn cast<U>(self) -> *mut U { + self as _ + } + + /// Returns `None` if the pointer is null, or else returns a reference to + /// the value wrapped in `Some`. + /// + /// # Safety + /// + /// While this method and its mutable counterpart are useful for + /// null-safety, it is important to note that this is still an unsafe + /// operation because the returned value could be pointing to invalid + /// memory. + /// + /// When calling this method, you have to ensure that if the pointer is + /// non-NULL, then it is properly aligned, dereferencable (for the whole + /// size of `T`) and points to an initialized instance of `T`. This applies + /// even if the result of this method is unused! + /// (The part about being initialized is not yet fully decided, but until + /// it is, the only safe approach is to ensure that they are indeed initialized.) + /// + /// Additionally, the lifetime `'a` returned is arbitrarily chosen and does + /// not necessarily reflect the actual lifetime of the data. It is up to the + /// caller to ensure that for the duration of this lifetime, the memory this + /// pointer points to does not get written to outside of `UnsafeCell<U>`. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// let ptr: *mut u8 = &mut 10u8 as *mut u8; + /// + /// unsafe { + /// if let Some(val_back) = ptr.as_ref() { + /// println!("We got back the value: {}!", val_back); + /// } + /// } + /// ``` + /// + /// # Null-unchecked version + /// + /// If you are sure the pointer can never be null and are looking for some kind of + /// `as_ref_unchecked` that returns the `&T` instead of `Option<&T>`, know that you can + /// dereference the pointer directly. + /// + /// ``` + /// let ptr: *mut u8 = &mut 10u8 as *mut u8; + /// + /// unsafe { + /// let val_back = &*ptr; + /// println!("We got back the value: {}!", val_back); + /// } + /// ``` + #[stable(feature = "ptr_as_ref", since = "1.9.0")] + #[inline] + pub unsafe fn as_ref<'a>(self) -> Option<&'a T> { + if self.is_null() { None } else { Some(&*self) } + } + + /// Calculates the offset from a pointer. + /// + /// `count` is in units of T; e.g., a `count` of 3 represents a pointer + /// offset of `3 * size_of::<T>()` bytes. + /// + /// # Safety + /// + /// If any of the following conditions are violated, the result is Undefined + /// Behavior: + /// + /// * Both the starting and resulting pointer must be either in bounds or one + /// byte past the end of the same allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// * The computed offset, **in bytes**, cannot overflow an `isize`. + /// + /// * The offset being in bounds cannot rely on "wrapping around" the address + /// space. That is, the infinite-precision sum, **in bytes** must fit in a usize. + /// + /// The compiler and standard library generally tries to ensure allocations + /// never reach a size where an offset is a concern. For instance, `Vec` + /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so + /// `vec.as_ptr().add(vec.len())` is always safe. + /// + /// Most platforms fundamentally can't even construct such an allocation. + /// For instance, no known 64-bit platform can ever serve a request + /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. + /// However, some 32-bit and 16-bit platforms may successfully serve a request for + /// more than `isize::MAX` bytes with things like Physical Address + /// Extension. As such, memory acquired directly from allocators or memory + /// mapped files *may* be too large to handle with this function. + /// + /// Consider using [`wrapping_offset`] instead if these constraints are + /// difficult to satisfy. The only advantage of this method is that it + /// enables more aggressive compiler optimizations. + /// + /// [`wrapping_offset`]: #method.wrapping_offset + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// let mut s = [1, 2, 3]; + /// let ptr: *mut u32 = s.as_mut_ptr(); + /// + /// unsafe { + /// println!("{}", *ptr.offset(1)); + /// println!("{}", *ptr.offset(2)); + /// } + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[inline] + pub unsafe fn offset(self, count: isize) -> *mut T + where + T: Sized, + { + intrinsics::offset(self, count) as *mut T + } + + /// Calculates the offset from a pointer using wrapping arithmetic. + /// `count` is in units of T; e.g., a `count` of 3 represents a pointer + /// offset of `3 * size_of::<T>()` bytes. + /// + /// # Safety + /// + /// The resulting pointer does not need to be in bounds, but it is + /// potentially hazardous to dereference (which requires `unsafe`). + /// + /// In particular, the resulting pointer remains attached to the same allocated + /// object that `self` points to. It may *not* be used to access a + /// different allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// In other words, `x.wrapping_offset(y.wrapping_offset_from(x))` is + /// *not* the same as `y`, and dereferencing it is undefined behavior + /// unless `x` and `y` point into the same allocated object. + /// + /// Compared to [`offset`], this method basically delays the requirement of staying + /// within the same allocated object: [`offset`] is immediate Undefined Behavior when + /// crossing object boundaries; `wrapping_offset` produces a pointer but still leads + /// to Undefined Behavior if that pointer is dereferenced. [`offset`] can be optimized + /// better and is thus preferrable in performance-sensitive code. + /// + /// If you need to cross object boundaries, cast the pointer to an integer and + /// do the arithmetic there. + /// + /// [`offset`]: #method.offset + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// // Iterate using a raw pointer in increments of two elements + /// let mut data = [1u8, 2, 3, 4, 5]; + /// let mut ptr: *mut u8 = data.as_mut_ptr(); + /// let step = 2; + /// let end_rounded_up = ptr.wrapping_offset(6); + /// + /// while ptr != end_rounded_up { + /// unsafe { + /// *ptr = 0; + /// } + /// ptr = ptr.wrapping_offset(step); + /// } + /// assert_eq!(&data, &[0, 2, 0, 4, 0]); + /// ``` + #[stable(feature = "ptr_wrapping_offset", since = "1.16.0")] + #[inline] + pub fn wrapping_offset(self, count: isize) -> *mut T + where + T: Sized, + { + unsafe { intrinsics::arith_offset(self, count) as *mut T } + } + + /// Returns `None` if the pointer is null, or else returns a mutable + /// reference to the value wrapped in `Some`. + /// + /// # Safety + /// + /// As with [`as_ref`], this is unsafe because it cannot verify the validity + /// of the returned pointer, nor can it ensure that the lifetime `'a` + /// returned is indeed a valid lifetime for the contained data. + /// + /// When calling this method, you have to ensure that *either* the pointer is NULL *or* + /// all of the following is true: + /// - it is properly aligned + /// - it must point to an initialized instance of T; in particular, the pointer must be + /// "dereferencable" in the sense defined [here]. + /// + /// This applies even if the result of this method is unused! + /// (The part about being initialized is not yet fully decided, but until + /// it is the only safe approach is to ensure that they are indeed initialized.) + /// + /// Additionally, the lifetime `'a` returned is arbitrarily chosen and does + /// not necessarily reflect the actual lifetime of the data. *You* must enforce + /// Rust's aliasing rules. In particular, for the duration of this lifetime, + /// the memory this pointer points to must not get accessed (read or written) + /// through any other pointer. + /// + /// [here]: crate::ptr#safety + /// [`as_ref`]: #method.as_ref + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// let mut s = [1, 2, 3]; + /// let ptr: *mut u32 = s.as_mut_ptr(); + /// let first_value = unsafe { ptr.as_mut().unwrap() }; + /// *first_value = 4; + /// println!("{:?}", s); // It'll print: "[4, 2, 3]". + /// ``` + #[stable(feature = "ptr_as_ref", since = "1.9.0")] + #[inline] + pub unsafe fn as_mut<'a>(self) -> Option<&'a mut T> { + if self.is_null() { None } else { Some(&mut *self) } + } + + /// Calculates the distance between two pointers. The returned value is in + /// units of T: the distance in bytes is divided by `mem::size_of::<T>()`. + /// + /// This function is the inverse of [`offset`]. + /// + /// [`offset`]: #method.offset-1 + /// [`wrapping_offset_from`]: #method.wrapping_offset_from-1 + /// + /// # Safety + /// + /// If any of the following conditions are violated, the result is Undefined + /// Behavior: + /// + /// * Both the starting and other pointer must be either in bounds or one + /// byte past the end of the same allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// * The distance between the pointers, **in bytes**, cannot overflow an `isize`. + /// + /// * The distance between the pointers, in bytes, must be an exact multiple + /// of the size of `T`. + /// + /// * The distance being in bounds cannot rely on "wrapping around" the address space. + /// + /// The compiler and standard library generally try to ensure allocations + /// never reach a size where an offset is a concern. For instance, `Vec` + /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so + /// `ptr_into_vec.offset_from(vec.as_ptr())` is always safe. + /// + /// Most platforms fundamentally can't even construct such an allocation. + /// For instance, no known 64-bit platform can ever serve a request + /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. + /// However, some 32-bit and 16-bit platforms may successfully serve a request for + /// more than `isize::MAX` bytes with things like Physical Address + /// Extension. As such, memory acquired directly from allocators or memory + /// mapped files *may* be too large to handle with this function. + /// + /// Consider using [`wrapping_offset_from`] instead if these constraints are + /// difficult to satisfy. The only advantage of this method is that it + /// enables more aggressive compiler optimizations. + /// + /// # Panics + /// + /// This function panics if `T` is a Zero-Sized Type ("ZST"). + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(ptr_offset_from)] + /// + /// let mut a = [0; 5]; + /// let ptr1: *mut i32 = &mut a[1]; + /// let ptr2: *mut i32 = &mut a[3]; + /// unsafe { + /// assert_eq!(ptr2.offset_from(ptr1), 2); + /// assert_eq!(ptr1.offset_from(ptr2), -2); + /// assert_eq!(ptr1.offset(2), ptr2); + /// assert_eq!(ptr2.offset(-2), ptr1); + /// } + /// ``` + #[unstable(feature = "ptr_offset_from", issue = "41079")] + #[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "41079")] + #[inline] + pub const unsafe fn offset_from(self, origin: *const T) -> isize + where + T: Sized, + { + (self as *const T).offset_from(origin) + } + + /// Calculates the distance between two pointers. The returned value is in + /// units of T: the distance in bytes is divided by `mem::size_of::<T>()`. + /// + /// If the address different between the two pointers is not a multiple of + /// `mem::size_of::<T>()` then the result of the division is rounded towards + /// zero. + /// + /// Though this method is safe for any two pointers, note that its result + /// will be mostly useless if the two pointers aren't into the same allocated + /// object, for example if they point to two different local variables. + /// + /// # Panics + /// + /// This function panics if `T` is a zero-sized type. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(ptr_wrapping_offset_from)] + /// + /// let mut a = [0; 5]; + /// let ptr1: *mut i32 = &mut a[1]; + /// let ptr2: *mut i32 = &mut a[3]; + /// assert_eq!(ptr2.wrapping_offset_from(ptr1), 2); + /// assert_eq!(ptr1.wrapping_offset_from(ptr2), -2); + /// assert_eq!(ptr1.wrapping_offset(2), ptr2); + /// assert_eq!(ptr2.wrapping_offset(-2), ptr1); + /// + /// let ptr1: *mut i32 = 3 as _; + /// let ptr2: *mut i32 = 13 as _; + /// assert_eq!(ptr2.wrapping_offset_from(ptr1), 2); + /// ``` + #[unstable(feature = "ptr_wrapping_offset_from", issue = "41079")] + #[inline] + pub fn wrapping_offset_from(self, origin: *const T) -> isize + where + T: Sized, + { + (self as *const T).wrapping_offset_from(origin) + } + + /// Calculates the offset from a pointer (convenience for `.offset(count as isize)`). + /// + /// `count` is in units of T; e.g., a `count` of 3 represents a pointer + /// offset of `3 * size_of::<T>()` bytes. + /// + /// # Safety + /// + /// If any of the following conditions are violated, the result is Undefined + /// Behavior: + /// + /// * Both the starting and resulting pointer must be either in bounds or one + /// byte past the end of the same allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// * The computed offset, **in bytes**, cannot overflow an `isize`. + /// + /// * The offset being in bounds cannot rely on "wrapping around" the address + /// space. That is, the infinite-precision sum must fit in a `usize`. + /// + /// The compiler and standard library generally tries to ensure allocations + /// never reach a size where an offset is a concern. For instance, `Vec` + /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so + /// `vec.as_ptr().add(vec.len())` is always safe. + /// + /// Most platforms fundamentally can't even construct such an allocation. + /// For instance, no known 64-bit platform can ever serve a request + /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. + /// However, some 32-bit and 16-bit platforms may successfully serve a request for + /// more than `isize::MAX` bytes with things like Physical Address + /// Extension. As such, memory acquired directly from allocators or memory + /// mapped files *may* be too large to handle with this function. + /// + /// Consider using [`wrapping_add`] instead if these constraints are + /// difficult to satisfy. The only advantage of this method is that it + /// enables more aggressive compiler optimizations. + /// + /// [`wrapping_add`]: #method.wrapping_add + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// let s: &str = "123"; + /// let ptr: *const u8 = s.as_ptr(); + /// + /// unsafe { + /// println!("{}", *ptr.add(1) as char); + /// println!("{}", *ptr.add(2) as char); + /// } + /// ``` + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn add(self, count: usize) -> Self + where + T: Sized, + { + self.offset(count as isize) + } + + /// Calculates the offset from a pointer (convenience for + /// `.offset((count as isize).wrapping_neg())`). + /// + /// `count` is in units of T; e.g., a `count` of 3 represents a pointer + /// offset of `3 * size_of::<T>()` bytes. + /// + /// # Safety + /// + /// If any of the following conditions are violated, the result is Undefined + /// Behavior: + /// + /// * Both the starting and resulting pointer must be either in bounds or one + /// byte past the end of the same allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// * The computed offset cannot exceed `isize::MAX` **bytes**. + /// + /// * The offset being in bounds cannot rely on "wrapping around" the address + /// space. That is, the infinite-precision sum must fit in a usize. + /// + /// The compiler and standard library generally tries to ensure allocations + /// never reach a size where an offset is a concern. For instance, `Vec` + /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so + /// `vec.as_ptr().add(vec.len()).sub(vec.len())` is always safe. + /// + /// Most platforms fundamentally can't even construct such an allocation. + /// For instance, no known 64-bit platform can ever serve a request + /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. + /// However, some 32-bit and 16-bit platforms may successfully serve a request for + /// more than `isize::MAX` bytes with things like Physical Address + /// Extension. As such, memory acquired directly from allocators or memory + /// mapped files *may* be too large to handle with this function. + /// + /// Consider using [`wrapping_sub`] instead if these constraints are + /// difficult to satisfy. The only advantage of this method is that it + /// enables more aggressive compiler optimizations. + /// + /// [`wrapping_sub`]: #method.wrapping_sub + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// let s: &str = "123"; + /// + /// unsafe { + /// let end: *const u8 = s.as_ptr().add(3); + /// println!("{}", *end.sub(1) as char); + /// println!("{}", *end.sub(2) as char); + /// } + /// ``` + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn sub(self, count: usize) -> Self + where + T: Sized, + { + self.offset((count as isize).wrapping_neg()) + } + + /// Calculates the offset from a pointer using wrapping arithmetic. + /// (convenience for `.wrapping_offset(count as isize)`) + /// + /// `count` is in units of T; e.g., a `count` of 3 represents a pointer + /// offset of `3 * size_of::<T>()` bytes. + /// + /// # Safety + /// + /// The resulting pointer does not need to be in bounds, but it is + /// potentially hazardous to dereference (which requires `unsafe`). + /// + /// In particular, the resulting pointer remains attached to the same allocated + /// object that `self` points to. It may *not* be used to access a + /// different allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// Compared to [`add`], this method basically delays the requirement of staying + /// within the same allocated object: [`add`] is immediate Undefined Behavior when + /// crossing object boundaries; `wrapping_add` produces a pointer but still leads + /// to Undefined Behavior if that pointer is dereferenced. [`add`] can be optimized + /// better and is thus preferrable in performance-sensitive code. + /// + /// If you need to cross object boundaries, cast the pointer to an integer and + /// do the arithmetic there. + /// + /// [`add`]: #method.add + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// // Iterate using a raw pointer in increments of two elements + /// let data = [1u8, 2, 3, 4, 5]; + /// let mut ptr: *const u8 = data.as_ptr(); + /// let step = 2; + /// let end_rounded_up = ptr.wrapping_add(6); + /// + /// // This loop prints "1, 3, 5, " + /// while ptr != end_rounded_up { + /// unsafe { + /// print!("{}, ", *ptr); + /// } + /// ptr = ptr.wrapping_add(step); + /// } + /// ``` + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub fn wrapping_add(self, count: usize) -> Self + where + T: Sized, + { + self.wrapping_offset(count as isize) + } + + /// Calculates the offset from a pointer using wrapping arithmetic. + /// (convenience for `.wrapping_offset((count as isize).wrapping_sub())`) + /// + /// `count` is in units of T; e.g., a `count` of 3 represents a pointer + /// offset of `3 * size_of::<T>()` bytes. + /// + /// # Safety + /// + /// The resulting pointer does not need to be in bounds, but it is + /// potentially hazardous to dereference (which requires `unsafe`). + /// + /// In particular, the resulting pointer remains attached to the same allocated + /// object that `self` points to. It may *not* be used to access a + /// different allocated object. Note that in Rust, + /// every (stack-allocated) variable is considered a separate allocated object. + /// + /// Compared to [`sub`], this method basically delays the requirement of staying + /// within the same allocated object: [`sub`] is immediate Undefined Behavior when + /// crossing object boundaries; `wrapping_sub` produces a pointer but still leads + /// to Undefined Behavior if that pointer is dereferenced. [`sub`] can be optimized + /// better and is thus preferrable in performance-sensitive code. + /// + /// If you need to cross object boundaries, cast the pointer to an integer and + /// do the arithmetic there. + /// + /// [`sub`]: #method.sub + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// // Iterate using a raw pointer in increments of two elements (backwards) + /// let data = [1u8, 2, 3, 4, 5]; + /// let mut ptr: *const u8 = data.as_ptr(); + /// let start_rounded_down = ptr.wrapping_sub(2); + /// ptr = ptr.wrapping_add(4); + /// let step = 2; + /// // This loop prints "5, 3, 1, " + /// while ptr != start_rounded_down { + /// unsafe { + /// print!("{}, ", *ptr); + /// } + /// ptr = ptr.wrapping_sub(step); + /// } + /// ``` + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub fn wrapping_sub(self, count: usize) -> Self + where + T: Sized, + { + self.wrapping_offset((count as isize).wrapping_neg()) + } + + /// Reads the value from `self` without moving it. This leaves the + /// memory in `self` unchanged. + /// + /// See [`ptr::read`] for safety concerns and examples. + /// + /// [`ptr::read`]: ./ptr/fn.read.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn read(self) -> T + where + T: Sized, + { + read(self) + } + + /// Performs a volatile read of the value from `self` without moving it. This + /// leaves the memory in `self` unchanged. + /// + /// Volatile operations are intended to act on I/O memory, and are guaranteed + /// to not be elided or reordered by the compiler across other volatile + /// operations. + /// + /// See [`ptr::read_volatile`] for safety concerns and examples. + /// + /// [`ptr::read_volatile`]: ./ptr/fn.read_volatile.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn read_volatile(self) -> T + where + T: Sized, + { + read_volatile(self) + } + + /// Reads the value from `self` without moving it. This leaves the + /// memory in `self` unchanged. + /// + /// Unlike `read`, the pointer may be unaligned. + /// + /// See [`ptr::read_unaligned`] for safety concerns and examples. + /// + /// [`ptr::read_unaligned`]: ./ptr/fn.read_unaligned.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn read_unaligned(self) -> T + where + T: Sized, + { + read_unaligned(self) + } + + /// Copies `count * size_of<T>` bytes from `self` to `dest`. The source + /// and destination may overlap. + /// + /// NOTE: this has the *same* argument order as [`ptr::copy`]. + /// + /// See [`ptr::copy`] for safety concerns and examples. + /// + /// [`ptr::copy`]: ./ptr/fn.copy.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn copy_to(self, dest: *mut T, count: usize) + where + T: Sized, + { + copy(self, dest, count) + } + + /// Copies `count * size_of<T>` bytes from `self` to `dest`. The source + /// and destination may *not* overlap. + /// + /// NOTE: this has the *same* argument order as [`ptr::copy_nonoverlapping`]. + /// + /// See [`ptr::copy_nonoverlapping`] for safety concerns and examples. + /// + /// [`ptr::copy_nonoverlapping`]: ./ptr/fn.copy_nonoverlapping.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn copy_to_nonoverlapping(self, dest: *mut T, count: usize) + where + T: Sized, + { + copy_nonoverlapping(self, dest, count) + } + + /// Copies `count * size_of<T>` bytes from `src` to `self`. The source + /// and destination may overlap. + /// + /// NOTE: this has the *opposite* argument order of [`ptr::copy`]. + /// + /// See [`ptr::copy`] for safety concerns and examples. + /// + /// [`ptr::copy`]: ./ptr/fn.copy.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn copy_from(self, src: *const T, count: usize) + where + T: Sized, + { + copy(src, self, count) + } + + /// Copies `count * size_of<T>` bytes from `src` to `self`. The source + /// and destination may *not* overlap. + /// + /// NOTE: this has the *opposite* argument order of [`ptr::copy_nonoverlapping`]. + /// + /// See [`ptr::copy_nonoverlapping`] for safety concerns and examples. + /// + /// [`ptr::copy_nonoverlapping`]: ./ptr/fn.copy_nonoverlapping.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn copy_from_nonoverlapping(self, src: *const T, count: usize) + where + T: Sized, + { + copy_nonoverlapping(src, self, count) + } + + /// Executes the destructor (if any) of the pointed-to value. + /// + /// See [`ptr::drop_in_place`] for safety concerns and examples. + /// + /// [`ptr::drop_in_place`]: ./ptr/fn.drop_in_place.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn drop_in_place(self) { + drop_in_place(self) + } + + /// Overwrites a memory location with the given value without reading or + /// dropping the old value. + /// + /// See [`ptr::write`] for safety concerns and examples. + /// + /// [`ptr::write`]: ./ptr/fn.write.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn write(self, val: T) + where + T: Sized, + { + write(self, val) + } + + /// Invokes memset on the specified pointer, setting `count * size_of::<T>()` + /// bytes of memory starting at `self` to `val`. + /// + /// See [`ptr::write_bytes`] for safety concerns and examples. + /// + /// [`ptr::write_bytes`]: ./ptr/fn.write_bytes.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn write_bytes(self, val: u8, count: usize) + where + T: Sized, + { + write_bytes(self, val, count) + } + + /// Performs a volatile write of a memory location with the given value without + /// reading or dropping the old value. + /// + /// Volatile operations are intended to act on I/O memory, and are guaranteed + /// to not be elided or reordered by the compiler across other volatile + /// operations. + /// + /// See [`ptr::write_volatile`] for safety concerns and examples. + /// + /// [`ptr::write_volatile`]: ./ptr/fn.write_volatile.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn write_volatile(self, val: T) + where + T: Sized, + { + write_volatile(self, val) + } + + /// Overwrites a memory location with the given value without reading or + /// dropping the old value. + /// + /// Unlike `write`, the pointer may be unaligned. + /// + /// See [`ptr::write_unaligned`] for safety concerns and examples. + /// + /// [`ptr::write_unaligned`]: ./ptr/fn.write_unaligned.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn write_unaligned(self, val: T) + where + T: Sized, + { + write_unaligned(self, val) + } + + /// Replaces the value at `self` with `src`, returning the old + /// value, without dropping either. + /// + /// See [`ptr::replace`] for safety concerns and examples. + /// + /// [`ptr::replace`]: ./ptr/fn.replace.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn replace(self, src: T) -> T + where + T: Sized, + { + replace(self, src) + } + + /// Swaps the values at two mutable locations of the same type, without + /// deinitializing either. They may overlap, unlike `mem::swap` which is + /// otherwise equivalent. + /// + /// See [`ptr::swap`] for safety concerns and examples. + /// + /// [`ptr::swap`]: ./ptr/fn.swap.html + #[stable(feature = "pointer_methods", since = "1.26.0")] + #[inline] + pub unsafe fn swap(self, with: *mut T) + where + T: Sized, + { + swap(self, with) + } + + /// Computes the offset that needs to be applied to the pointer in order to make it aligned to + /// `align`. + /// + /// If it is not possible to align the pointer, the implementation returns + /// `usize::max_value()`. It is permissible for the implementation to *always* + /// return `usize::max_value()`. Only your algorithm's performance can depend + /// on getting a usable offset here, not its correctness. + /// + /// The offset is expressed in number of `T` elements, and not bytes. The value returned can be + /// used with the `wrapping_add` method. + /// + /// There are no guarantees whatsoever that offsetting the pointer will not overflow or go + /// beyond the allocation that the pointer points into. It is up to the caller to ensure that + /// the returned offset is correct in all terms other than alignment. + /// + /// # Panics + /// + /// The function panics if `align` is not a power-of-two. + /// + /// # Examples + /// + /// Accessing adjacent `u8` as `u16` + /// + /// ``` + /// # fn foo(n: usize) { + /// # use std::mem::align_of; + /// # unsafe { + /// let x = [5u8, 6u8, 7u8, 8u8, 9u8]; + /// let ptr = &x[n] as *const u8; + /// let offset = ptr.align_offset(align_of::<u16>()); + /// if offset < x.len() - n - 1 { + /// let u16_ptr = ptr.add(offset) as *const u16; + /// assert_ne!(*u16_ptr, 500); + /// } else { + /// // while the pointer can be aligned via `offset`, it would point + /// // outside the allocation + /// } + /// # } } + /// ``` + #[stable(feature = "align_offset", since = "1.36.0")] + pub fn align_offset(self, align: usize) -> usize + where + T: Sized, + { + if !align.is_power_of_two() { + panic!("align_offset: align is not a power-of-two"); + } + unsafe { align_offset(self, align) } + } +} + +// Equality for pointers +#[stable(feature = "rust1", since = "1.0.0")] +impl<T: ?Sized> PartialEq for *mut T { + #[inline] + fn eq(&self, other: &*mut T) -> bool { *self == *other } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl<T: ?Sized> Eq for *mut T {} + +#[stable(feature = "rust1", since = "1.0.0")] +impl<T: ?Sized> Ord for *mut T { + #[inline] + fn cmp(&self, other: &*mut T) -> Ordering { + if self < other { + Less + } else if self == other { + Equal + } else { + Greater + } + } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl<T: ?Sized> PartialOrd for *mut T { + #[inline] + fn partial_cmp(&self, other: &*mut T) -> Option<Ordering> { + Some(self.cmp(other)) + } + + #[inline] + fn lt(&self, other: &*mut T) -> bool { *self < *other } + + #[inline] + fn le(&self, other: &*mut T) -> bool { *self <= *other } + + #[inline] + fn gt(&self, other: &*mut T) -> bool { *self > *other } + + #[inline] + fn ge(&self, other: &*mut T) -> bool { *self >= *other } +} diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs index 6b354b01518..2cffcc5bfad 100644 --- a/src/librustc/hir/mod.rs +++ b/src/librustc/hir/mod.rs @@ -1857,6 +1857,16 @@ impl fmt::Display for YieldSource { } } +impl From<GeneratorKind> for YieldSource { + fn from(kind: GeneratorKind) -> Self { + match kind { + // Guess based on the kind of the current generator. + GeneratorKind::Gen => Self::Yield, + GeneratorKind::Async(_) => Self::Await, + } + } +} + // N.B., if you change this, you'll probably want to change the corresponding // type structure in middle/ty.rs as well. #[derive(RustcEncodable, RustcDecodable, Debug, HashStable)] diff --git a/src/librustc/middle/region.rs b/src/librustc/middle/region.rs index aa6f2839828..e050e5f8942 100644 --- a/src/librustc/middle/region.rs +++ b/src/librustc/middle/region.rs @@ -1173,6 +1173,7 @@ fn resolve_local<'tcx>( /// | VariantName(..., P&, ...) /// | [ ..., P&, ... ] /// | ( ..., P&, ... ) + /// | ... "|" P& "|" ... /// | box P& fn is_binding_pat(pat: &hir::Pat) -> bool { // Note that the code below looks for *explicit* refs only, that is, it won't @@ -1212,6 +1213,7 @@ fn resolve_local<'tcx>( pats3.iter().any(|p| is_binding_pat(&p)) } + PatKind::Or(ref subpats) | PatKind::TupleStruct(_, ref subpats, _) | PatKind::Tuple(ref subpats, _) => { subpats.iter().any(|p| is_binding_pat(&p)) @@ -1221,7 +1223,13 @@ fn resolve_local<'tcx>( is_binding_pat(&subpat) } - _ => false, + PatKind::Ref(_, _) | + PatKind::Binding(hir::BindingAnnotation::Unannotated, ..) | + PatKind::Binding(hir::BindingAnnotation::Mutable, ..) | + PatKind::Wild | + PatKind::Path(_) | + PatKind::Lit(_) | + PatKind::Range(_, _, _) => false, } } diff --git a/src/librustc_mir/borrow_check/diagnostics/region_errors.rs b/src/librustc_mir/borrow_check/diagnostics/region_errors.rs index 8a37e2d02ec..b78cd6bccf8 100644 --- a/src/librustc_mir/borrow_check/diagnostics/region_errors.rs +++ b/src/librustc_mir/borrow_check/diagnostics/region_errors.rs @@ -1,10 +1,13 @@ //! Error reporting machinery for lifetime errors. use rustc::hir::def_id::DefId; -use rustc::infer::error_reporting::nice_region_error::NiceRegionError; -use rustc::infer::InferCtxt; -use rustc::infer::NLLRegionVariableOrigin; -use rustc::mir::{ConstraintCategory, Local, Location, Body}; +use rustc::infer::{ + error_reporting::nice_region_error::NiceRegionError, + InferCtxt, NLLRegionVariableOrigin, +}; +use rustc::mir::{ + ConstraintCategory, Local, Location, Body, +}; use rustc::ty::{self, RegionVid}; use rustc_index::vec::IndexVec; use rustc_errors::DiagnosticBuilder; @@ -93,6 +96,32 @@ pub struct ErrorConstraintInfo { } impl<'tcx> RegionInferenceContext<'tcx> { + /// Converts a region inference variable into a `ty::Region` that + /// we can use for error reporting. If `r` is universally bound, + /// then we use the name that we have on record for it. If `r` is + /// existentially bound, then we check its inferred value and try + /// to find a good name from that. Returns `None` if we can't find + /// one (e.g., this is just some random part of the CFG). + pub fn to_error_region(&self, r: RegionVid) -> Option<ty::Region<'tcx>> { + self.to_error_region_vid(r).and_then(|r| self.definitions[r].external_name) + } + + /// Returns the [RegionVid] corresponding to the region returned by + /// `to_error_region`. + pub fn to_error_region_vid(&self, r: RegionVid) -> Option<RegionVid> { + if self.universal_regions.is_universal_region(r) { + Some(r) + } else { + let r_scc = self.constraint_sccs.scc(r); + let upper_bound = self.universal_upper_bound(r); + if self.scc_values.contains(r_scc, upper_bound) { + self.to_error_region_vid(upper_bound) + } else { + None + } + } + } + /// Tries to find the best constraint to blame for the fact that /// `R: from_region`, where `R` is some region that meets /// `target_test`. This works by following the constraint graph, diff --git a/src/librustc_mir/borrow_check/region_infer/mod.rs b/src/librustc_mir/borrow_check/region_infer/mod.rs index b6946e2f73f..dedc6b9b09a 100644 --- a/src/librustc_mir/borrow_check/region_infer/mod.rs +++ b/src/librustc_mir/borrow_check/region_infer/mod.rs @@ -928,32 +928,6 @@ impl<'tcx> RegionInferenceContext<'tcx> { } } - /// Converts a region inference variable into a `ty::Region` that - /// we can use for error reporting. If `r` is universally bound, - /// then we use the name that we have on record for it. If `r` is - /// existentially bound, then we check its inferred value and try - /// to find a good name from that. Returns `None` if we can't find - /// one (e.g., this is just some random part of the CFG). - pub fn to_error_region(&self, r: RegionVid) -> Option<ty::Region<'tcx>> { - self.to_error_region_vid(r).and_then(|r| self.definitions[r].external_name) - } - - /// Returns the [RegionVid] corresponding to the region returned by - /// `to_error_region`. - pub fn to_error_region_vid(&self, r: RegionVid) -> Option<RegionVid> { - if self.universal_regions.is_universal_region(r) { - Some(r) - } else { - let r_scc = self.constraint_sccs.scc(r); - let upper_bound = self.universal_upper_bound(r); - if self.scc_values.contains(r_scc, upper_bound) { - self.to_error_region_vid(upper_bound) - } else { - None - } - } - } - /// Invoked when we have some type-test (e.g., `T: 'X`) that we cannot /// prove to be satisfied. If this is a closure, we will attempt to /// "promote" this type-test into our `ClosureRegionRequirements` and @@ -1164,7 +1138,7 @@ impl<'tcx> RegionInferenceContext<'tcx> { /// include the CFG anyhow. /// - For each `end('x)` element in `'r`, compute the mutual LUB, yielding /// a result `'y`. - fn universal_upper_bound(&self, r: RegionVid) -> RegionVid { + pub (in crate::borrow_check) fn universal_upper_bound(&self, r: RegionVid) -> RegionVid { debug!("universal_upper_bound(r={:?}={})", r, self.region_value_str(r)); // Find the smallest universal region that contains all other @@ -1458,19 +1432,34 @@ impl<'tcx> RegionInferenceContext<'tcx> { debug!("check_polonius_subset_errors: subset_error longer_fr={:?},\ shorter_fr={:?}", longer_fr, shorter_fr); - self.report_or_propagate_universal_region_error( + let propagated = self.try_propagate_universal_region_error( *longer_fr, *shorter_fr, - infcx, body, - local_names, - upvars, - mir_def_id, &mut propagated_outlives_requirements, - &mut outlives_suggestion, - errors_buffer, - region_naming, ); + if !propagated { + // If we are not in a context where we can't propagate errors, or we + // could not shrink `fr` to something smaller, then just report an + // error. + // + // Note: in this case, we use the unapproximated regions to report the + // error. This gives better error messages in some cases. + let db = self.report_error( + body, + local_names, + upvars, + infcx, + mir_def_id, + *longer_fr, + NLLRegionVariableOrigin::FreeRegion, + *shorter_fr, + &mut outlives_suggestion, + region_naming, + ); + + db.buffer(errors_buffer); + } } // Handle the placeholder errors as usual, until the chalk-rustc-polonius triumvirate has @@ -1594,48 +1583,59 @@ impl<'tcx> RegionInferenceContext<'tcx> { return None; } - self.report_or_propagate_universal_region_error( + let propagated = self.try_propagate_universal_region_error( longer_fr, shorter_fr, - infcx, body, - local_names, - upvars, - mir_def_id, propagated_outlives_requirements, - outlives_suggestion, - errors_buffer, - region_naming, - ) + ); + + if propagated { + None + } else { + // If we are not in a context where we can't propagate errors, or we + // could not shrink `fr` to something smaller, then just report an + // error. + // + // Note: in this case, we use the unapproximated regions to report the + // error. This gives better error messages in some cases. + let db = self.report_error( + body, + local_names, + upvars, + infcx, + mir_def_id, + longer_fr, + NLLRegionVariableOrigin::FreeRegion, + shorter_fr, + outlives_suggestion, + region_naming, + ); + + db.buffer(errors_buffer); + + Some(ErrorReported) + } } - fn report_or_propagate_universal_region_error( + /// Attempt to propagate a region error (e.g. `'a: 'b`) that is not met to a closure's + /// creator. If we cannot, then the caller should report an error to the user. + /// + /// Returns `true` if the error was propagated, and `false` otherwise. + fn try_propagate_universal_region_error( &self, longer_fr: RegionVid, shorter_fr: RegionVid, - infcx: &InferCtxt<'_, 'tcx>, body: &Body<'tcx>, - local_names: &IndexVec<Local, Option<Symbol>>, - upvars: &[Upvar], - mir_def_id: DefId, propagated_outlives_requirements: &mut Option<&mut Vec<ClosureOutlivesRequirement<'tcx>>>, - outlives_suggestion: &mut OutlivesSuggestionBuilder<'_>, - errors_buffer: &mut Vec<Diagnostic>, - region_naming: &mut RegionErrorNamingCtx, - ) -> Option<ErrorReported> { - debug!( - "report_or_propagate_universal_region_error: fr={:?} does not outlive shorter_fr={:?}", - longer_fr, shorter_fr, - ); - + ) -> bool { if let Some(propagated_outlives_requirements) = propagated_outlives_requirements { // Shrink `longer_fr` until we find a non-local region (if we do). // We'll call it `fr-` -- it's ever so slightly smaller than // `longer_fr`. - if let Some(fr_minus) = self.universal_region_relations.non_local_lower_bound(longer_fr) { - debug!("report_or_propagate_universal_region_error: fr_minus={:?}", fr_minus); + debug!("try_propagate_universal_region_error: fr_minus={:?}", fr_minus); let blame_span_category = self.find_outlives_blame_span(body, longer_fr, @@ -1648,7 +1648,7 @@ impl<'tcx> RegionInferenceContext<'tcx> { .universal_region_relations .non_local_upper_bounds(&shorter_fr); debug!( - "report_or_propagate_universal_region_error: shorter_fr_plus={:?}", + "try_propagate_universal_region_error: shorter_fr_plus={:?}", shorter_fr_plus ); for &&fr in &shorter_fr_plus { @@ -1660,32 +1660,11 @@ impl<'tcx> RegionInferenceContext<'tcx> { category: blame_span_category.0, }); } - return None; + return true; } } - // If we are not in a context where we can't propagate errors, or we - // could not shrink `fr` to something smaller, then just report an - // error. - // - // Note: in this case, we use the unapproximated regions to report the - // error. This gives better error messages in some cases. - let db = self.report_error( - body, - local_names, - upvars, - infcx, - mir_def_id, - longer_fr, - NLLRegionVariableOrigin::FreeRegion, - shorter_fr, - outlives_suggestion, - region_naming, - ); - - db.buffer(errors_buffer); - - Some(ErrorReported) + false } fn check_bound_universal_region( diff --git a/src/librustc_mir/dataflow/move_paths/builder.rs b/src/librustc_mir/dataflow/move_paths/builder.rs index 5522da6fbf0..0b8f41f51a1 100644 --- a/src/librustc_mir/dataflow/move_paths/builder.rs +++ b/src/librustc_mir/dataflow/move_paths/builder.rs @@ -103,6 +103,13 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> { } }; + // The move path index of the first union that we find. Once this is + // some we stop creating child move paths, since moves from unions + // move the whole thing. + // We continue looking for other move errors though so that moving + // from `*(u.f: &_)` isn't allowed. + let mut union_path = None; + for (i, elem) in place.projection.iter().enumerate() { let proj_base = &place.projection[..i]; let body = self.builder.body; @@ -127,9 +134,8 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> { InteriorOfTypeWithDestructor { container_ty: place_ty }, )); } - // move out of union - always move the entire union ty::Adt(adt, _) if adt.is_union() => { - return Err(MoveError::UnionMove { path: base }); + union_path.get_or_insert(base); } ty::Slice(_) => { return Err(MoveError::cannot_move_out_of( @@ -155,15 +161,22 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> { _ => {} }; - base = self.add_move_path(base, elem, |tcx| { - Place { - base: place.base.clone(), - projection: tcx.intern_place_elems(&place.projection[..i+1]), - } - }); + if union_path.is_none() { + base = self.add_move_path(base, elem, |tcx| { + Place { + base: place.base.clone(), + projection: tcx.intern_place_elems(&place.projection[..i+1]), + } + }); + } } - Ok(base) + if let Some(base) = union_path { + // Move out of union - always move the entire union. + Err(MoveError::UnionMove { path: base }) + } else { + Ok(base) + } } fn add_move_path( diff --git a/src/librustc_mir/transform/const_prop.rs b/src/librustc_mir/transform/const_prop.rs index c4d89b1494d..62aec1975c2 100644 --- a/src/librustc_mir/transform/const_prop.rs +++ b/src/librustc_mir/transform/const_prop.rs @@ -262,7 +262,7 @@ struct ConstPropagator<'mir, 'tcx> { ecx: InterpCx<'mir, 'tcx, ConstPropMachine>, tcx: TyCtxt<'tcx>, source: MirSource<'tcx>, - can_const_prop: IndexVec<Local, bool>, + can_const_prop: IndexVec<Local, ConstPropMode>, param_env: ParamEnv<'tcx>, // FIXME(eddyb) avoid cloning these two fields more than once, // by accessing them through `ecx` instead. @@ -708,17 +708,28 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { } } +/// The mode that `ConstProp` is allowed to run in for a given `Local`. +#[derive(Clone, Copy, Debug, PartialEq)] +enum ConstPropMode { + /// The `Local` can be propagated into and reads of this `Local` can also be propagated. + FullConstProp, + /// The `Local` can be propagated into but reads cannot be propagated. + OnlyPropagateInto, + /// No propagation is allowed at all. + NoPropagation, +} + struct CanConstProp { - can_const_prop: IndexVec<Local, bool>, + can_const_prop: IndexVec<Local, ConstPropMode>, // false at the beginning, once set, there are not allowed to be any more assignments found_assignment: IndexVec<Local, bool>, } impl CanConstProp { /// returns true if `local` can be propagated - fn check(body: ReadOnlyBodyAndCache<'_, '_>) -> IndexVec<Local, bool> { + fn check(body: ReadOnlyBodyAndCache<'_, '_>) -> IndexVec<Local, ConstPropMode> { let mut cpv = CanConstProp { - can_const_prop: IndexVec::from_elem(true, &body.local_decls), + can_const_prop: IndexVec::from_elem(ConstPropMode::FullConstProp, &body.local_decls), found_assignment: IndexVec::from_elem(false, &body.local_decls), }; for (local, val) in cpv.can_const_prop.iter_enumerated_mut() { @@ -728,10 +739,10 @@ impl CanConstProp { // FIXME(oli-obk): lint variables until they are used in a condition // FIXME(oli-obk): lint if return value is constant let local_kind = body.local_kind(local); - *val = local_kind == LocalKind::Temp || local_kind == LocalKind::ReturnPointer; - if !*val { - trace!("local {:?} can't be propagated because it's not a temporary", local); + if local_kind == LocalKind::Arg || local_kind == LocalKind::Var { + *val = ConstPropMode::OnlyPropagateInto; + trace!("local {:?} can't be const propagated because it's not a temporary", local); } } cpv.visit_body(body); @@ -753,7 +764,7 @@ impl<'tcx> Visitor<'tcx> for CanConstProp { // only occur in independent execution paths MutatingUse(MutatingUseContext::Store) => if self.found_assignment[local] { trace!("local {:?} can't be propagated because of multiple assignments", local); - self.can_const_prop[local] = false; + self.can_const_prop[local] = ConstPropMode::NoPropagation; } else { self.found_assignment[local] = true }, @@ -766,7 +777,7 @@ impl<'tcx> Visitor<'tcx> for CanConstProp { NonUse(_) => {}, _ => { trace!("local {:?} can't be propagaged because it's used: {:?}", local, context); - self.can_const_prop[local] = false; + self.can_const_prop[local] = ConstPropMode::NoPropagation; }, } } @@ -800,10 +811,10 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> { if let Ok(place_layout) = self.tcx.layout_of(self.param_env.and(place_ty)) { if let Some(local) = place.as_local() { let source = statement.source_info; + let can_const_prop = self.can_const_prop[local]; if let Some(()) = self.const_prop(rval, place_layout, source, place) { - if self.can_const_prop[local] { - trace!("propagated into {:?}", local); - + if can_const_prop == ConstPropMode::FullConstProp || + can_const_prop == ConstPropMode::OnlyPropagateInto { if let Some(value) = self.get_const(local) { if self.should_const_prop(value) { trace!("replacing {:?} with {:?}", rval, value); @@ -812,13 +823,18 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> { value, statement.source_info, ); + + if can_const_prop == ConstPropMode::FullConstProp { + trace!("propagated into {:?}", local); + } } } - } else { - trace!("can't propagate into {:?}", local); - if local != RETURN_PLACE { - self.remove_const(local); - } + } + } + if self.can_const_prop[local] != ConstPropMode::FullConstProp { + trace!("can't propagate into {:?}", local); + if local != RETURN_PLACE { + self.remove_const(local); } } } @@ -826,7 +842,7 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> { } else { match statement.kind { StatementKind::StorageLive(local) | - StatementKind::StorageDead(local) if self.can_const_prop[local] => { + StatementKind::StorageDead(local) => { let frame = self.ecx.frame_mut(); frame.locals[local].value = if let StatementKind::StorageLive(_) = statement.kind { diff --git a/src/librustc_typeck/check/generator_interior.rs b/src/librustc_typeck/check/generator_interior.rs index fcf6b22f74f..607efca88dd 100644 --- a/src/librustc_typeck/check/generator_interior.rs +++ b/src/librustc_typeck/check/generator_interior.rs @@ -19,6 +19,7 @@ struct InteriorVisitor<'a, 'tcx> { region_scope_tree: &'tcx region::ScopeTree, expr_count: usize, kind: hir::GeneratorKind, + prev_unresolved_span: Option<Span>, } impl<'a, 'tcx> InteriorVisitor<'a, 'tcx> { @@ -32,7 +33,6 @@ impl<'a, 'tcx> InteriorVisitor<'a, 'tcx> { debug!("generator_interior: attempting to record type {:?} {:?} {:?} {:?}", ty, scope, expr, source_span); - let live_across_yield = scope.map(|s| { self.region_scope_tree.yield_in_scope(s).and_then(|yield_data| { // If we are recording an expression that is the last yield @@ -54,15 +54,11 @@ impl<'a, 'tcx> InteriorVisitor<'a, 'tcx> { }).unwrap_or_else(|| Some(YieldData { span: DUMMY_SP, expr_and_pat_count: 0, - source: match self.kind { // Guess based on the kind of the current generator. - hir::GeneratorKind::Gen => hir::YieldSource::Yield, - hir::GeneratorKind::Async(_) => hir::YieldSource::Await, - }, + source: self.kind.into(), })); if let Some(yield_data) = live_across_yield { let ty = self.fcx.resolve_vars_if_possible(&ty); - debug!("type in expr = {:?}, scope = {:?}, type = {:?}, count = {}, yield_span = {:?}", expr, scope, ty, self.expr_count, yield_data.span); @@ -74,9 +70,12 @@ impl<'a, 'tcx> InteriorVisitor<'a, 'tcx> { yield_data.source); // If unresolved type isn't a ty_var then unresolved_type_span is None + let span = self.prev_unresolved_span.unwrap_or_else( + || unresolved_type_span.unwrap_or(source_span) + ); self.fcx.need_type_info_err_in_generator( self.kind, - unresolved_type_span.unwrap_or(source_span), + span, unresolved_type, ) .span_note(yield_data.span, &*note) @@ -94,6 +93,13 @@ impl<'a, 'tcx> InteriorVisitor<'a, 'tcx> { } else { debug!("no type in expr = {:?}, count = {:?}, span = {:?}", expr, self.expr_count, expr.map(|e| e.span)); + let ty = self.fcx.resolve_vars_if_possible(&ty); + if let Some((unresolved_type, unresolved_type_span)) + = self.fcx.unresolved_type_vars(&ty) { + debug!("remained unresolved_type = {:?}, unresolved_type_span: {:?}", + unresolved_type, unresolved_type_span); + self.prev_unresolved_span = unresolved_type_span; + } } } } @@ -112,6 +118,7 @@ pub fn resolve_interior<'a, 'tcx>( region_scope_tree: fcx.tcx.region_scope_tree(def_id), expr_count: 0, kind, + prev_unresolved_span: None, }; intravisit::walk_body(&mut visitor, body); diff --git a/src/test/mir-opt/const_prop/aggregate.rs b/src/test/mir-opt/const_prop/aggregate.rs index 0937d37be6b..d04dcc6a05c 100644 --- a/src/test/mir-opt/const_prop/aggregate.rs +++ b/src/test/mir-opt/const_prop/aggregate.rs @@ -19,7 +19,7 @@ fn main() { // ... // _3 = (const 0i32, const 1i32, const 2i32); // _2 = const 1i32; -// _1 = Add(move _2, const 0i32); +// _1 = const 1i32; // ... // } // END rustc.main.ConstProp.after.mir diff --git a/src/test/mir-opt/const_prop/array_index.rs b/src/test/mir-opt/const_prop/array_index.rs index dd22eb5d604..406585b5cab 100644 --- a/src/test/mir-opt/const_prop/array_index.rs +++ b/src/test/mir-opt/const_prop/array_index.rs @@ -26,7 +26,7 @@ fn main() { // assert(const true, "index out of bounds: the len is move _4 but the index is _3") -> bb1; // } // bb1: { -// _1 = _2[_3]; +// _1 = const 2u32; // ... // return; // } diff --git a/src/test/mir-opt/const_prop/optimizes_into_variable.rs b/src/test/mir-opt/const_prop/optimizes_into_variable.rs new file mode 100644 index 00000000000..93a53db9093 --- /dev/null +++ b/src/test/mir-opt/const_prop/optimizes_into_variable.rs @@ -0,0 +1,149 @@ +// compile-flags: -C overflow-checks=on + +struct Point { + x: u32, + y: u32, +} + +fn main() { + let x = 2 + 2; + let y = [0, 1, 2, 3, 4, 5][3]; + let z = (Point { x: 12, y: 42}).y; +} + +// END RUST SOURCE +// START rustc.main.ConstProp.before.mir +// let mut _0: (); +// let _1: i32; +// let mut _2: (i32, bool); +// let mut _4: [i32; 6]; +// let _5: usize; +// let mut _6: usize; +// let mut _7: bool; +// let mut _9: Point; +// scope 1 { +// debug x => _1; +// let _3: i32; +// scope 2 { +// debug y => _3; +// let _8: u32; +// scope 3 { +// debug z => _8; +// } +// } +// } +// bb0: { +// StorageLive(_1); +// _2 = CheckedAdd(const 2i32, const 2i32); +// assert(!move (_2.1: bool), "attempt to add with overflow") -> bb1; +// } +// bb1: { +// _1 = move (_2.0: i32); +// StorageLive(_3); +// StorageLive(_4); +// _4 = [const 0i32, const 1i32, const 2i32, const 3i32, const 4i32, const 5i32]; +// StorageLive(_5); +// _5 = const 3usize; +// _6 = const 6usize; +// _7 = Lt(_5, _6); +// assert(move _7, "index out of bounds: the len is move _6 but the index is _5") -> bb2; +// } +// bb2: { +// _3 = _4[_5]; +// StorageDead(_5); +// StorageDead(_4); +// StorageLive(_8); +// StorageLive(_9); +// _9 = Point { x: const 12u32, y: const 42u32 }; +// _8 = (_9.1: u32); +// StorageDead(_9); +// _0 = (); +// StorageDead(_8); +// StorageDead(_3); +// StorageDead(_1); +// return; +// } +// END rustc.main.ConstProp.before.mir +// START rustc.main.ConstProp.after.mir +// let mut _0: (); +// let _1: i32; +// let mut _2: (i32, bool); +// let mut _4: [i32; 6]; +// let _5: usize; +// let mut _6: usize; +// let mut _7: bool; +// let mut _9: Point; +// scope 1 { +// debug x => _1; +// let _3: i32; +// scope 2 { +// debug y => _3; +// let _8: u32; +// scope 3 { +// debug z => _8; +// } +// } +// } +// bb0: { +// StorageLive(_1); +// _2 = (const 4i32, const false); +// assert(!const false, "attempt to add with overflow") -> bb1; +// } +// bb1: { +// _1 = const 4i32; +// StorageLive(_3); +// StorageLive(_4); +// _4 = [const 0i32, const 1i32, const 2i32, const 3i32, const 4i32, const 5i32]; +// StorageLive(_5); +// _5 = const 3usize; +// _6 = const 6usize; +// _7 = const true; +// assert(const true, "index out of bounds: the len is move _6 but the index is _5") -> bb2; +// } +// bb2: { +// _3 = const 3i32; +// StorageDead(_5); +// StorageDead(_4); +// StorageLive(_8); +// StorageLive(_9); +// _9 = Point { x: const 12u32, y: const 42u32 }; +// _8 = const 42u32; +// StorageDead(_9); +// _0 = (); +// StorageDead(_8); +// StorageDead(_3); +// StorageDead(_1); +// return; +// } +// END rustc.main.ConstProp.after.mir +// START rustc.main.SimplifyLocals.after.mir +// let mut _0: (); +// let _1: i32; +// let mut _3: [i32; 6]; +// scope 1 { +// debug x => _1; +// let _2: i32; +// scope 2 { +// debug y => _2; +// let _4: u32; +// scope 3 { +// debug z => _4; +// } +// } +// } +// bb0: { +// StorageLive(_1); +// _1 = const 4i32; +// StorageLive(_2); +// StorageLive(_3); +// _3 = [const 0i32, const 1i32, const 2i32, const 3i32, const 4i32, const 5i32]; +// _2 = const 3i32; +// StorageDead(_3); +// StorageLive(_4); +// _4 = const 42u32; +// StorageDead(_4); +// StorageDead(_2); +// StorageDead(_1); +// return; +// } +// END rustc.main.SimplifyLocals.after.mir diff --git a/src/test/mir-opt/const_prop/read_immutable_static.rs b/src/test/mir-opt/const_prop/read_immutable_static.rs index d14ec039716..d9e0eb623af 100644 --- a/src/test/mir-opt/const_prop/read_immutable_static.rs +++ b/src/test/mir-opt/const_prop/read_immutable_static.rs @@ -25,7 +25,7 @@ fn main() { // _2 = const 2u8; // ... // _4 = const 2u8; -// _1 = Add(move _2, move _4); +// _1 = const 4u8; // ... // } // END rustc.main.ConstProp.after.mir diff --git a/src/test/mir-opt/const_prop/repeat.rs b/src/test/mir-opt/const_prop/repeat.rs index fb091ad2a3d..48c06290cec 100644 --- a/src/test/mir-opt/const_prop/repeat.rs +++ b/src/test/mir-opt/const_prop/repeat.rs @@ -30,7 +30,7 @@ fn main() { // } // bb1: { // _2 = const 42u32; -// _1 = Add(move _2, const 0u32); +// _1 = const 42u32; // ... // return; // } diff --git a/src/test/ui/borrowck/move-from-union-field-issue-66500.rs b/src/test/ui/borrowck/move-from-union-field-issue-66500.rs new file mode 100644 index 00000000000..8fbf120fc1c --- /dev/null +++ b/src/test/ui/borrowck/move-from-union-field-issue-66500.rs @@ -0,0 +1,30 @@ +// Moving from a reference/raw pointer should be an error, even when they're +// the field of a union. + +#![feature(untagged_unions)] + +union Pointers { + a: &'static String, + b: &'static mut String, + c: *const String, + d: *mut String, +} + +unsafe fn move_ref(u: Pointers) -> String { + *u.a + //~^ ERROR cannot move out of `*u.a` +} +unsafe fn move_ref_mut(u: Pointers) -> String { + *u.b + //~^ ERROR cannot move out of `*u.b` +} +unsafe fn move_ptr(u: Pointers) -> String { + *u.c + //~^ ERROR cannot move out of `*u.c` +} +unsafe fn move_ptr_mut(u: Pointers) -> String { + *u.d + //~^ ERROR cannot move out of `*u.d` +} + +fn main() {} diff --git a/src/test/ui/borrowck/move-from-union-field-issue-66500.stderr b/src/test/ui/borrowck/move-from-union-field-issue-66500.stderr new file mode 100644 index 00000000000..a7cb1c9e221 --- /dev/null +++ b/src/test/ui/borrowck/move-from-union-field-issue-66500.stderr @@ -0,0 +1,27 @@ +error[E0507]: cannot move out of `*u.a` which is behind a shared reference + --> $DIR/move-from-union-field-issue-66500.rs:14:5 + | +LL | *u.a + | ^^^^ move occurs because `*u.a` has type `std::string::String`, which does not implement the `Copy` trait + +error[E0507]: cannot move out of `*u.b` which is behind a mutable reference + --> $DIR/move-from-union-field-issue-66500.rs:18:5 + | +LL | *u.b + | ^^^^ move occurs because `*u.b` has type `std::string::String`, which does not implement the `Copy` trait + +error[E0507]: cannot move out of `*u.c` which is behind a raw pointer + --> $DIR/move-from-union-field-issue-66500.rs:22:5 + | +LL | *u.c + | ^^^^ move occurs because `*u.c` has type `std::string::String`, which does not implement the `Copy` trait + +error[E0507]: cannot move out of `*u.d` which is behind a raw pointer + --> $DIR/move-from-union-field-issue-66500.rs:26:5 + | +LL | *u.d + | ^^^^ move occurs because `*u.d` has type `std::string::String`, which does not implement the `Copy` trait + +error: aborting due to 4 previous errors + +For more information about this error, try `rustc --explain E0507`. diff --git a/src/test/ui/consts/offset_from_ub.stderr b/src/test/ui/consts/offset_from_ub.stderr index 1bd09034bfc..ac08b2f2427 100644 --- a/src/test/ui/consts/offset_from_ub.stderr +++ b/src/test/ui/consts/offset_from_ub.stderr @@ -1,11 +1,11 @@ error: any use of this value will cause an error - --> $SRC_DIR/libcore/ptr/mod.rs:LL:COL + --> $SRC_DIR/libcore/ptr/const_ptr.rs:LL:COL | LL | intrinsics::ptr_offset_from(self, origin) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | ptr_offset_from cannot compute offset of pointers into different allocations. - | inside call to `std::ptr::<impl *const Struct>::offset_from` at $DIR/offset_from_ub.rs:19:27 + | inside call to `std::ptr::const_ptr::<impl *const Struct>::offset_from` at $DIR/offset_from_ub.rs:19:27 | ::: $DIR/offset_from_ub.rs:13:1 | @@ -21,13 +21,13 @@ LL | | }; = note: `#[deny(const_err)]` on by default error: any use of this value will cause an error - --> $SRC_DIR/libcore/ptr/mod.rs:LL:COL + --> $SRC_DIR/libcore/ptr/const_ptr.rs:LL:COL | LL | intrinsics::ptr_offset_from(self, origin) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | a memory access tried to interpret some bytes as a pointer - | inside call to `std::ptr::<impl *const u8>::offset_from` at $DIR/offset_from_ub.rs:25:14 + | inside call to `std::ptr::const_ptr::<impl *const u8>::offset_from` at $DIR/offset_from_ub.rs:25:14 | ::: $DIR/offset_from_ub.rs:23:1 | @@ -38,13 +38,13 @@ LL | | }; | |__- error: any use of this value will cause an error - --> $SRC_DIR/libcore/ptr/mod.rs:LL:COL + --> $SRC_DIR/libcore/ptr/const_ptr.rs:LL:COL | LL | intrinsics::ptr_offset_from(self, origin) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | exact_div: 1 cannot be divided by 2 without remainder - | inside call to `std::ptr::<impl *const u16>::offset_from` at $DIR/offset_from_ub.rs:33:14 + | inside call to `std::ptr::const_ptr::<impl *const u16>::offset_from` at $DIR/offset_from_ub.rs:33:14 | ::: $DIR/offset_from_ub.rs:28:1 | @@ -58,13 +58,13 @@ LL | | }; | |__- error: any use of this value will cause an error - --> $SRC_DIR/libcore/ptr/mod.rs:LL:COL + --> $SRC_DIR/libcore/ptr/const_ptr.rs:LL:COL | LL | intrinsics::ptr_offset_from(self, origin) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | invalid use of NULL pointer - | inside call to `std::ptr::<impl *const u8>::offset_from` at $DIR/offset_from_ub.rs:39:14 + | inside call to `std::ptr::const_ptr::<impl *const u8>::offset_from` at $DIR/offset_from_ub.rs:39:14 | ::: $DIR/offset_from_ub.rs:36:1 | @@ -76,13 +76,13 @@ LL | | }; | |__- error: any use of this value will cause an error - --> $SRC_DIR/libcore/ptr/mod.rs:LL:COL + --> $SRC_DIR/libcore/ptr/const_ptr.rs:LL:COL | LL | intrinsics::ptr_offset_from(self, origin) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | a memory access tried to interpret some bytes as a pointer - | inside call to `std::ptr::<impl *const u8>::offset_from` at $DIR/offset_from_ub.rs:46:14 + | inside call to `std::ptr::const_ptr::<impl *const u8>::offset_from` at $DIR/offset_from_ub.rs:46:14 | ::: $DIR/offset_from_ub.rs:42:1 | |