From ab9362ad9a9b4b93951ccb577224dda367923226 Mon Sep 17 00:00:00 2001 From: Tim Diekmann Date: Tue, 4 Aug 2020 18:03:34 +0200 Subject: [PATCH] Replace `Memoryblock` with `NonNull<[u8]>` --- library/alloc/src/alloc.rs | 30 +++-- library/alloc/src/alloc/tests.rs | 6 +- library/alloc/src/boxed.rs | 4 +- library/alloc/src/lib.rs | 3 + library/alloc/src/raw_vec.rs | 30 ++--- library/alloc/src/raw_vec/tests.rs | 2 +- library/alloc/src/rc.rs | 4 +- library/alloc/src/sync.rs | 6 +- library/alloc/tests/heap.rs | 9 +- library/alloc/tests/lib.rs | 1 + library/core/src/alloc/mod.rs | 140 ++++++++++---------- library/std/src/alloc.rs | 28 ++-- library/std/src/lib.rs | 3 + src/test/ui/allocator/custom.rs | 9 +- src/test/ui/allocator/xcrate-use.rs | 9 +- src/test/ui/realloc-16687.rs | 13 +- src/test/ui/regions/regions-mock-codegen.rs | 4 +- 17 files changed, 158 insertions(+), 143 deletions(-) diff --git a/library/alloc/src/alloc.rs b/library/alloc/src/alloc.rs index 111ef406c00..518ac11b5a0 100644 --- a/library/alloc/src/alloc.rs +++ b/library/alloc/src/alloc.rs @@ -164,7 +164,7 @@ pub unsafe fn alloc_zeroed(layout: Layout) -> *mut u8 { #[unstable(feature = "allocator_api", issue = "32838")] unsafe impl AllocRef for Global { #[inline] - fn alloc(&mut self, layout: Layout) -> Result { + fn alloc(&mut self, layout: Layout) -> Result, AllocErr> { let size = layout.size(); let ptr = if size == 0 { layout.dangling() @@ -172,11 +172,11 @@ unsafe impl AllocRef for Global { // SAFETY: `layout` is non-zero in size, unsafe { NonNull::new(alloc(layout)).ok_or(AllocErr)? } }; - Ok(MemoryBlock { ptr, size }) + Ok(NonNull::slice_from_raw_parts(ptr, size)) } #[inline] - fn alloc_zeroed(&mut self, layout: Layout) -> Result { + fn alloc_zeroed(&mut self, layout: Layout) -> Result, AllocErr> { let size = layout.size(); let ptr = if size == 0 { layout.dangling() @@ -184,7 +184,7 @@ unsafe impl AllocRef for Global { // SAFETY: `layout` is non-zero in size, unsafe { NonNull::new(alloc_zeroed(layout)).ok_or(AllocErr)? } }; - Ok(MemoryBlock { ptr, size }) + Ok(NonNull::slice_from_raw_parts(ptr, size)) } #[inline] @@ -202,7 +202,7 @@ unsafe impl AllocRef for Global { ptr: NonNull, layout: Layout, new_size: usize, - ) -> Result { + ) -> Result, AllocErr> { debug_assert!( new_size >= layout.size(), "`new_size` must be greater than or equal to `layout.size()`" @@ -212,14 +212,16 @@ unsafe impl AllocRef for Global { // Other conditions must be upheld by the caller unsafe { match layout.size() { - old_size if old_size == new_size => Ok(MemoryBlock { ptr, size: new_size }), + old_size if old_size == new_size => { + Ok(NonNull::slice_from_raw_parts(ptr, new_size)) + } 0 => self.alloc(Layout::from_size_align_unchecked(new_size, layout.align())), old_size => { // `realloc` probably checks for `new_size > size` or something similar. intrinsics::assume(new_size > old_size); let raw_ptr = realloc(ptr.as_ptr(), layout, new_size); let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?; - Ok(MemoryBlock { ptr, size: new_size }) + Ok(NonNull::slice_from_raw_parts(ptr, new_size)) } } } @@ -231,7 +233,7 @@ unsafe impl AllocRef for Global { ptr: NonNull, layout: Layout, new_size: usize, - ) -> Result { + ) -> Result, AllocErr> { debug_assert!( new_size >= layout.size(), "`new_size` must be greater than or equal to `layout.size()`" @@ -241,7 +243,9 @@ unsafe impl AllocRef for Global { // Other conditions must be upheld by the caller unsafe { match layout.size() { - old_size if old_size == new_size => Ok(MemoryBlock { ptr, size: new_size }), + old_size if old_size == new_size => { + Ok(NonNull::slice_from_raw_parts(ptr, new_size)) + } 0 => self.alloc_zeroed(Layout::from_size_align_unchecked(new_size, layout.align())), old_size => { // `realloc` probably checks for `new_size > size` or something similar. @@ -249,7 +253,7 @@ unsafe impl AllocRef for Global { let raw_ptr = realloc(ptr.as_ptr(), layout, new_size); raw_ptr.add(old_size).write_bytes(0, new_size - old_size); let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?; - Ok(MemoryBlock { ptr, size: new_size }) + Ok(NonNull::slice_from_raw_parts(ptr, new_size)) } } } @@ -261,7 +265,7 @@ unsafe impl AllocRef for Global { ptr: NonNull, layout: Layout, new_size: usize, - ) -> Result { + ) -> Result, AllocErr> { let old_size = layout.size(); debug_assert!( new_size <= old_size, @@ -288,7 +292,7 @@ unsafe impl AllocRef for Global { NonNull::new(raw_ptr).ok_or(AllocErr)? }; - Ok(MemoryBlock { ptr, size: new_size }) + Ok(NonNull::slice_from_raw_parts(ptr, new_size)) } } @@ -300,7 +304,7 @@ unsafe impl AllocRef for Global { unsafe fn exchange_malloc(size: usize, align: usize) -> *mut u8 { let layout = unsafe { Layout::from_size_align_unchecked(size, align) }; match Global.alloc(layout) { - Ok(memory) => memory.ptr.as_ptr(), + Ok(ptr) => ptr.as_non_null_ptr().as_ptr(), Err(_) => handle_alloc_error(layout), } } diff --git a/library/alloc/src/alloc/tests.rs b/library/alloc/src/alloc/tests.rs index 2b4cb946bb4..f7463d0daac 100644 --- a/library/alloc/src/alloc/tests.rs +++ b/library/alloc/src/alloc/tests.rs @@ -8,16 +8,16 @@ use test::Bencher; fn allocate_zeroed() { unsafe { let layout = Layout::from_size_align(1024, 1).unwrap(); - let memory = + let ptr = Global.alloc_zeroed(layout.clone()).unwrap_or_else(|_| handle_alloc_error(layout)); - let mut i = memory.ptr.cast::().as_ptr(); + let mut i = ptr.as_non_null_ptr().as_ptr(); let end = i.add(layout.size()); while i < end { assert_eq!(*i, 0); i = i.offset(1); } - Global.dealloc(memory.ptr, layout); + Global.dealloc(ptr.as_non_null_ptr(), layout); } } diff --git a/library/alloc/src/boxed.rs b/library/alloc/src/boxed.rs index cff219ec29d..5e304beff78 100644 --- a/library/alloc/src/boxed.rs +++ b/library/alloc/src/boxed.rs @@ -197,8 +197,7 @@ impl Box { #[unstable(feature = "new_uninit", issue = "63291")] pub fn new_uninit() -> Box> { let layout = alloc::Layout::new::>(); - let ptr = - Global.alloc(layout).unwrap_or_else(|_| alloc::handle_alloc_error(layout)).ptr.cast(); + let ptr = Global.alloc(layout).unwrap_or_else(|_| alloc::handle_alloc_error(layout)).cast(); unsafe { Box::from_raw(ptr.as_ptr()) } } @@ -226,7 +225,6 @@ impl Box { let ptr = Global .alloc_zeroed(layout) .unwrap_or_else(|_| alloc::handle_alloc_error(layout)) - .ptr .cast(); unsafe { Box::from_raw(ptr.as_ptr()) } } diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs index 097db30d634..9ac23886d4e 100644 --- a/library/alloc/src/lib.rs +++ b/library/alloc/src/lib.rs @@ -104,6 +104,7 @@ #![feature(negative_impls)] #![feature(new_uninit)] #![feature(nll)] +#![feature(nonnull_slice_from_raw_parts)] #![feature(optin_builtin_traits)] #![feature(or_patterns)] #![feature(pattern)] @@ -113,6 +114,8 @@ #![feature(rustc_attrs)] #![feature(receiver_trait)] #![feature(min_specialization)] +#![feature(slice_ptr_get)] +#![feature(slice_ptr_len)] #![feature(staged_api)] #![feature(std_internals)] #![feature(str_internals)] diff --git a/library/alloc/src/raw_vec.rs b/library/alloc/src/raw_vec.rs index 99ac027bf0b..2abd7231711 100644 --- a/library/alloc/src/raw_vec.rs +++ b/library/alloc/src/raw_vec.rs @@ -1,7 +1,7 @@ #![unstable(feature = "raw_vec_internals", reason = "implementation detail", issue = "none")] #![doc(hidden)] -use core::alloc::{LayoutErr, MemoryBlock}; +use core::alloc::LayoutErr; use core::cmp; use core::mem::{self, ManuallyDrop, MaybeUninit}; use core::ops::Drop; @@ -186,14 +186,14 @@ impl RawVec { AllocInit::Uninitialized => alloc.alloc(layout), AllocInit::Zeroed => alloc.alloc_zeroed(layout), }; - let memory = match result { - Ok(memory) => memory, + let ptr = match result { + Ok(ptr) => ptr, Err(_) => handle_alloc_error(layout), }; Self { - ptr: unsafe { Unique::new_unchecked(memory.ptr.cast().as_ptr()) }, - cap: Self::capacity_from_bytes(memory.size), + ptr: unsafe { Unique::new_unchecked(ptr.cast().as_ptr()) }, + cap: Self::capacity_from_bytes(ptr.len()), alloc, } } @@ -384,9 +384,9 @@ impl RawVec { excess / mem::size_of::() } - fn set_memory(&mut self, memory: MemoryBlock) { - self.ptr = unsafe { Unique::new_unchecked(memory.ptr.cast().as_ptr()) }; - self.cap = Self::capacity_from_bytes(memory.size); + fn set_ptr(&mut self, ptr: NonNull<[u8]>) { + self.ptr = unsafe { Unique::new_unchecked(ptr.cast().as_ptr()) }; + self.cap = Self::capacity_from_bytes(ptr.len()); } // This method is usually instantiated many times. So we want it to be as @@ -432,8 +432,8 @@ impl RawVec { let new_layout = Layout::array::(cap); // `finish_grow` is non-generic over `T`. - let memory = finish_grow(new_layout, self.current_memory(), &mut self.alloc)?; - self.set_memory(memory); + let ptr = finish_grow(new_layout, self.current_memory(), &mut self.alloc)?; + self.set_ptr(ptr); Ok(()) } @@ -451,8 +451,8 @@ impl RawVec { let new_layout = Layout::array::(cap); // `finish_grow` is non-generic over `T`. - let memory = finish_grow(new_layout, self.current_memory(), &mut self.alloc)?; - self.set_memory(memory); + let ptr = finish_grow(new_layout, self.current_memory(), &mut self.alloc)?; + self.set_ptr(ptr); Ok(()) } @@ -462,13 +462,13 @@ impl RawVec { let (ptr, layout) = if let Some(mem) = self.current_memory() { mem } else { return Ok(()) }; let new_size = amount * mem::size_of::(); - let memory = unsafe { + let ptr = unsafe { self.alloc.shrink(ptr, layout, new_size).map_err(|_| TryReserveError::AllocError { layout: Layout::from_size_align_unchecked(new_size, layout.align()), non_exhaustive: (), })? }; - self.set_memory(memory); + self.set_ptr(ptr); Ok(()) } } @@ -481,7 +481,7 @@ fn finish_grow( new_layout: Result, current_memory: Option<(NonNull, Layout)>, alloc: &mut A, -) -> Result +) -> Result, TryReserveError> where A: AllocRef, { diff --git a/library/alloc/src/raw_vec/tests.rs b/library/alloc/src/raw_vec/tests.rs index 08a5cbee5a7..cadd913aa6b 100644 --- a/library/alloc/src/raw_vec/tests.rs +++ b/library/alloc/src/raw_vec/tests.rs @@ -20,7 +20,7 @@ fn allocator_param() { fuel: usize, } unsafe impl AllocRef for BoundedAlloc { - fn alloc(&mut self, layout: Layout) -> Result { + fn alloc(&mut self, layout: Layout) -> Result, AllocErr> { let size = layout.size(); if size > self.fuel { return Err(AllocErr); diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs index c0c638292bb..d0a47ccea0a 100644 --- a/library/alloc/src/rc.rs +++ b/library/alloc/src/rc.rs @@ -928,10 +928,10 @@ impl Rc { let layout = Layout::new::>().extend(value_layout).unwrap().0.pad_to_align(); // Allocate for the layout. - let mem = Global.alloc(layout).unwrap_or_else(|_| handle_alloc_error(layout)); + let ptr = Global.alloc(layout).unwrap_or_else(|_| handle_alloc_error(layout)); // Initialize the RcBox - let inner = mem_to_rcbox(mem.ptr.as_ptr()); + let inner = mem_to_rcbox(ptr.as_non_null_ptr().as_ptr()); unsafe { debug_assert_eq!(Layout::for_value(&*inner), layout); diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs index 7d5f24ec4ad..b3763303137 100644 --- a/library/alloc/src/sync.rs +++ b/library/alloc/src/sync.rs @@ -883,10 +883,10 @@ impl Arc { // reference (see #54908). let layout = Layout::new::>().extend(value_layout).unwrap().0.pad_to_align(); - let mem = Global.alloc(layout).unwrap_or_else(|_| handle_alloc_error(layout)); + let ptr = Global.alloc(layout).unwrap_or_else(|_| handle_alloc_error(layout)); // Initialize the ArcInner - let inner = mem_to_arcinner(mem.ptr.as_ptr()); + let inner = mem_to_arcinner(ptr.as_non_null_ptr().as_ptr()); debug_assert_eq!(unsafe { Layout::for_value(&*inner) }, layout); unsafe { @@ -986,7 +986,7 @@ impl Arc<[T]> { let slice = from_raw_parts_mut(self.elems, self.n_elems); ptr::drop_in_place(slice); - Global.dealloc(self.mem.cast(), self.layout); + Global.dealloc(self.mem, self.layout); } } } diff --git a/library/alloc/tests/heap.rs b/library/alloc/tests/heap.rs index a05340dc79a..cbde2a7e28e 100644 --- a/library/alloc/tests/heap.rs +++ b/library/alloc/tests/heap.rs @@ -20,12 +20,12 @@ fn check_overalign_requests(mut allocator: T) { unsafe { let pointers: Vec<_> = (0..iterations) .map(|_| { - allocator.alloc(Layout::from_size_align(size, align).unwrap()).unwrap().ptr + allocator.alloc(Layout::from_size_align(size, align).unwrap()).unwrap() }) .collect(); for &ptr in &pointers { assert_eq!( - (ptr.as_ptr() as usize) % align, + (ptr.as_non_null_ptr().as_ptr() as usize) % align, 0, "Got a pointer less aligned than requested" ) @@ -33,7 +33,10 @@ fn check_overalign_requests(mut allocator: T) { // Clean up for &ptr in &pointers { - allocator.dealloc(ptr, Layout::from_size_align(size, align).unwrap()) + allocator.dealloc( + ptr.as_non_null_ptr(), + Layout::from_size_align(size, align).unwrap(), + ) } } } diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs index fa20a466715..c680a3fc25b 100644 --- a/library/alloc/tests/lib.rs +++ b/library/alloc/tests/lib.rs @@ -13,6 +13,7 @@ #![feature(associated_type_bounds)] #![feature(binary_heap_into_iter_sorted)] #![feature(binary_heap_drain_sorted)] +#![feature(slice_ptr_get)] #![feature(split_inclusive)] #![feature(binary_heap_retain)] diff --git a/library/core/src/alloc/mod.rs b/library/core/src/alloc/mod.rs index 9ab5352c1dd..00ca03a714b 100644 --- a/library/core/src/alloc/mod.rs +++ b/library/core/src/alloc/mod.rs @@ -29,14 +29,6 @@ impl fmt::Display for AllocErr { } } -/// Represents a block of allocated memory returned by an allocator. -#[derive(Debug, Copy, Clone)] -#[unstable(feature = "allocator_api", issue = "32838")] -pub struct MemoryBlock { - pub ptr: NonNull, - pub size: usize, -} - /// An implementation of `AllocRef` can allocate, grow, shrink, and deallocate arbitrary blocks of /// data described via [`Layout`][]. /// @@ -50,13 +42,13 @@ pub struct MemoryBlock { /// /// ### Currently allocated memory /// -/// Some of the methods require that a memory block be *currently allocated* via an allocator. This +/// Some of the methods require that a memory slice be *currently allocated* via an allocator. This /// means that: /// -/// * the starting address for that memory block was previously returned by [`alloc`], [`grow`], or +/// * the starting address for that memory slice was previously returned by [`alloc`], [`grow`], or /// [`shrink`], and /// -/// * the memory block has not been subsequently deallocated, where blocks are either deallocated +/// * the memory slice has not been subsequently deallocated, where slices are either deallocated /// directly by being passed to [`dealloc`] or were changed by being passed to [`grow`] or /// [`shrink`] that returns `Ok`. If `grow` or `shrink` have returned `Err`, the passed pointer /// remains valid. @@ -68,14 +60,14 @@ pub struct MemoryBlock { /// /// ### Memory fitting /// -/// Some of the methods require that a layout *fit* a memory block. What it means for a layout to -/// "fit" a memory block means (or equivalently, for a memory block to "fit" a layout) is that the +/// Some of the methods require that a layout *fit* a memory slice. What it means for a layout to +/// "fit" a memory slice means (or equivalently, for a memory slice to "fit" a layout) is that the /// following conditions must hold: /// -/// * The block must be allocated with the same alignment as [`layout.align()`], and +/// * The slice must be allocated with the same alignment as [`layout.align()`], and /// /// * The provided [`layout.size()`] must fall in the range `min ..= max`, where: -/// - `min` is the size of the layout most recently used to allocate the block, and +/// - `min` is the size of the layout most recently used to allocate the slice, and /// - `max` is the latest actual size returned from [`alloc`], [`grow`], or [`shrink`]. /// /// [`layout.align()`]: Layout::align @@ -83,25 +75,27 @@ pub struct MemoryBlock { /// /// # Safety /// -/// * Memory blocks returned from an allocator must point to valid memory and retain their validity +/// * Memory slices returned from an allocator must point to valid memory and retain their validity /// until the instance and all of its clones are dropped, /// -/// * cloning or moving the allocator must not invalidate memory blocks returned from this +/// * cloning or moving the allocator must not invalidate memory slices returned from this /// allocator. A cloned allocator must behave like the same allocator, and /// -/// * any pointer to a memory block which is [*currently allocated*] may be passed to any other +/// * any pointer to a memory slice which is [*currently allocated*] may be passed to any other /// method of the allocator. /// /// [*currently allocated*]: #currently-allocated-memory #[unstable(feature = "allocator_api", issue = "32838")] pub unsafe trait AllocRef { - /// Attempts to allocate a block of memory. + /// Attempts to allocate a slice of memory. /// - /// On success, returns a [`MemoryBlock`][] meeting the size and alignment guarantees of `layout`. + /// On success, returns a [`NonNull<[u8]>`] meeting the size and alignment guarantees of `layout`. /// - /// The returned block may have a larger size than specified by `layout.size()`, and may or may + /// The returned slice may have a larger size than specified by `layout.size()`, and may or may /// not have its contents initialized. /// + /// [`NonNull<[u8]>`]: NonNull + /// /// # Errors /// /// Returning `Err` indicates that either memory is exhausted or `layout` does not meet @@ -115,7 +109,7 @@ pub unsafe trait AllocRef { /// call the [`handle_alloc_error`] function, rather than directly invoking `panic!` or similar. /// /// [`handle_alloc_error`]: ../../alloc/alloc/fn.handle_alloc_error.html - fn alloc(&mut self, layout: Layout) -> Result; + fn alloc(&mut self, layout: Layout) -> Result, AllocErr>; /// Behaves like `alloc`, but also ensures that the returned memory is zero-initialized. /// @@ -132,27 +126,27 @@ pub unsafe trait AllocRef { /// call the [`handle_alloc_error`] function, rather than directly invoking `panic!` or similar. /// /// [`handle_alloc_error`]: ../../alloc/alloc/fn.handle_alloc_error.html - fn alloc_zeroed(&mut self, layout: Layout) -> Result { - let memory = self.alloc(layout)?; - // SAFETY: `alloc` returns a valid memory block - unsafe { memory.ptr.as_ptr().write_bytes(0, memory.size) } - Ok(memory) + fn alloc_zeroed(&mut self, layout: Layout) -> Result, AllocErr> { + let ptr = self.alloc(layout)?; + // SAFETY: `alloc` returns a valid memory slice + unsafe { ptr.as_non_null_ptr().as_ptr().write_bytes(0, ptr.len()) } + Ok(ptr) } - /// Deallocates the memory referenced by `ptr`. + /// Deallocates the memory slice referenced by `ptr`. /// /// # Safety /// - /// * `ptr` must denote a block of memory [*currently allocated*] via this allocator, and - /// * `layout` must [*fit*] that block of memory. + /// * `ptr` must denote a slice of memory [*currently allocated*] via this allocator, and + /// * `layout` must [*fit*] that slice of memory. /// /// [*currently allocated*]: #currently-allocated-memory /// [*fit*]: #memory-fitting unsafe fn dealloc(&mut self, ptr: NonNull, layout: Layout); - /// Attempts to extend the memory block. + /// Attempts to extend the memory slice. /// - /// Returns a new [`MemoryBlock`][] containing a pointer and the actual size of the allocated + /// Returns a new [`NonNull<[u8]>`] containing a pointer and the actual size of the allocated /// memory. The pointer is suitable for holding data described by a new layout with `layout`’s /// alignment and a size given by `new_size`. To accomplish this, the allocator may extend the /// allocation referenced by `ptr` to fit the new layout. @@ -160,6 +154,8 @@ pub unsafe trait AllocRef { /// If this method returns `Err`, then ownership of the memory block has not been transferred to /// this allocator, and the contents of the memory block are unaltered. /// + /// [`NonNull<[u8]>`]: NonNull + /// /// # Safety /// /// * `ptr` must denote a block of memory [*currently allocated*] via this allocator, @@ -168,7 +164,7 @@ pub unsafe trait AllocRef { /// * `new_size`, when rounded up to the nearest multiple of `layout.align()`, must not overflow /// (i.e., the rounded value must be less than or equal to `usize::MAX`). // Note: We can't require that `new_size` is strictly greater than `layout.size()` because of ZSTs. - // alternative: `new_size must be strictly greater than `layout.size()` or both are zero + // alternative: `new_size` must be strictly greater than `layout.size()` or both are zero /// /// [*currently allocated*]: #currently-allocated-memory /// [*fit*]: #memory-fitting @@ -191,15 +187,15 @@ pub unsafe trait AllocRef { ptr: NonNull, layout: Layout, new_size: usize, - ) -> Result { + ) -> Result, AllocErr> { let size = layout.size(); debug_assert!( new_size >= size, "`new_size` must be greater than or equal to `layout.size()`" ); - if new_size == size { - return Ok(MemoryBlock { ptr, size }); + if size == new_size { + return Ok(NonNull::slice_from_raw_parts(ptr, size)); } let new_layout = @@ -208,17 +204,17 @@ pub unsafe trait AllocRef { // The caller must ensure that `new_size` is greater than or equal to zero. If it's equal // to zero, it's catched beforehand. unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) }; - let new_memory = self.alloc(new_layout)?; + let new_ptr = self.alloc(new_layout)?; // SAFETY: because `new_size` must be greater than or equal to `size`, both the old and new // memory allocation are valid for reads and writes for `size` bytes. Also, because the old - // allocation wasn't yet deallocated, it cannot overlap `new_memory`. Thus, the call to + // allocation wasn't yet deallocated, it cannot overlap `new_ptr`. Thus, the call to // `copy_nonoverlapping` is safe. // The safety contract for `dealloc` must be upheld by the caller. unsafe { - ptr::copy_nonoverlapping(ptr.as_ptr(), new_memory.ptr.as_ptr(), size); + ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_non_null_ptr().as_ptr(), size); self.dealloc(ptr, layout); - Ok(new_memory) + Ok(new_ptr) } } @@ -239,12 +235,11 @@ pub unsafe trait AllocRef { /// /// * `ptr` must denote a block of memory [*currently allocated*] via this allocator, /// * `layout` must [*fit*] that block of memory (The `new_size` argument need not fit it.), - // We can't require that `new_size` is strictly greater than `memory.size` because of ZSTs. - // An alternative would be - // * `new_size must be strictly greater than `memory.size` or both are zero /// * `new_size` must be greater than or equal to `layout.size()`, and /// * `new_size`, when rounded up to the nearest multiple of `layout.align()`, must not overflow /// (i.e., the rounded value must be less than or equal to `usize::MAX`). + // Note: We can't require that `new_size` is strictly greater than `layout.size()` because of ZSTs. + // alternative: `new_size` must be strictly greater than `layout.size()` or both are zero /// /// [*currently allocated*]: #currently-allocated-memory /// [*fit*]: #memory-fitting @@ -267,15 +262,15 @@ pub unsafe trait AllocRef { ptr: NonNull, layout: Layout, new_size: usize, - ) -> Result { + ) -> Result, AllocErr> { let size = layout.size(); debug_assert!( new_size >= size, "`new_size` must be greater than or equal to `layout.size()`" ); - if new_size == size { - return Ok(MemoryBlock { ptr, size }); + if size == new_size { + return Ok(NonNull::slice_from_raw_parts(ptr, size)); } let new_layout = @@ -284,43 +279,44 @@ pub unsafe trait AllocRef { // The caller must ensure that `new_size` is greater than or equal to zero. If it's equal // to zero, it's caught beforehand. unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) }; - let new_memory = self.alloc_zeroed(new_layout)?; + let new_ptr = self.alloc_zeroed(new_layout)?; // SAFETY: because `new_size` must be greater than or equal to `size`, both the old and new // memory allocation are valid for reads and writes for `size` bytes. Also, because the old - // allocation wasn't yet deallocated, it cannot overlap `new_memory`. Thus, the call to + // allocation wasn't yet deallocated, it cannot overlap `new_ptr`. Thus, the call to // `copy_nonoverlapping` is safe. // The safety contract for `dealloc` must be upheld by the caller. unsafe { - ptr::copy_nonoverlapping(ptr.as_ptr(), new_memory.ptr.as_ptr(), size); + ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_non_null_ptr().as_ptr(), size); self.dealloc(ptr, layout); - Ok(new_memory) + Ok(new_ptr) } } - /// Attempts to shrink the memory block. + /// Attempts to shrink the memory slice. /// - /// Returns a new [`MemoryBlock`][] containing a pointer and the actual size of the allocated + /// Returns a new [`NonNull<[u8]>`] containing a pointer and the actual size of the allocated /// memory. The pointer is suitable for holding data described by a new layout with `layout`’s /// alignment and a size given by `new_size`. To accomplish this, the allocator may shrink the /// allocation referenced by `ptr` to fit the new layout. /// - /// If this returns `Ok`, then ownership of the memory block referenced by `ptr` has been + /// If this returns `Ok`, then ownership of the memory slice referenced by `ptr` has been /// transferred to this allocator. The memory may or may not have been freed, and should be /// considered unusable unless it was transferred back to the caller again via the /// return value of this method. /// - /// If this method returns `Err`, then ownership of the memory block has not been transferred to - /// this allocator, and the contents of the memory block are unaltered. + /// If this method returns `Err`, then ownership of the memory slice has not been transferred to + /// this allocator, and the contents of the memory slice are unaltered. + /// + /// [`NonNull<[u8]>`]: NonNull /// /// # Safety /// - /// * `ptr` must denote a block of memory [*currently allocated*] via this allocator, - /// * `layout` must [*fit*] that block of memory (The `new_size` argument need not fit it.), and - // We can't require that `new_size` is strictly smaller than `memory.size` because of ZSTs. - // An alternative would be - // * `new_size must be strictly smaller than `memory.size` or both are zero + /// * `ptr` must denote a slice of memory [*currently allocated*] via this allocator, + /// * `layout` must [*fit*] that slice of memory (The `new_size` argument need not fit it.), and /// * `new_size` must be smaller than or equal to `layout.size()`. + // Note: We can't require that `new_size` is strictly smaller than `layout.size()` because of ZSTs. + // alternative: `new_size` must be smaller than `layout.size()` or both are zero /// /// [*currently allocated*]: #currently-allocated-memory /// [*fit*]: #memory-fitting @@ -343,15 +339,15 @@ pub unsafe trait AllocRef { ptr: NonNull, layout: Layout, new_size: usize, - ) -> Result { + ) -> Result, AllocErr> { let size = layout.size(); debug_assert!( new_size <= size, "`new_size` must be smaller than or equal to `layout.size()`" ); - if new_size == size { - return Ok(MemoryBlock { ptr, size }); + if size == new_size { + return Ok(NonNull::slice_from_raw_parts(ptr, size)); } let new_layout = @@ -359,17 +355,17 @@ pub unsafe trait AllocRef { // `layout.align()` comes from a `Layout` and is thus guaranteed to be valid for a Layout. // The caller must ensure that `new_size` is greater than zero. unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) }; - let new_memory = self.alloc(new_layout)?; + let new_ptr = self.alloc(new_layout)?; // SAFETY: because `new_size` must be lower than or equal to `size`, both the old and new // memory allocation are valid for reads and writes for `new_size` bytes. Also, because the - // old allocation wasn't yet deallocated, it cannot overlap `new_memory`. Thus, the call to + // old allocation wasn't yet deallocated, it cannot overlap `new_ptr`. Thus, the call to // `copy_nonoverlapping` is safe. // The safety contract for `dealloc` must be upheld by the caller. unsafe { - ptr::copy_nonoverlapping(ptr.as_ptr(), new_memory.ptr.as_ptr(), new_size); + ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_non_null_ptr().as_ptr(), size); self.dealloc(ptr, layout); - Ok(new_memory) + Ok(new_ptr) } } @@ -388,12 +384,12 @@ where A: AllocRef + ?Sized, { #[inline] - fn alloc(&mut self, layout: Layout) -> Result { + fn alloc(&mut self, layout: Layout) -> Result, AllocErr> { (**self).alloc(layout) } #[inline] - fn alloc_zeroed(&mut self, layout: Layout) -> Result { + fn alloc_zeroed(&mut self, layout: Layout) -> Result, AllocErr> { (**self).alloc_zeroed(layout) } @@ -409,7 +405,7 @@ where ptr: NonNull, layout: Layout, new_size: usize, - ) -> Result { + ) -> Result, AllocErr> { // SAFETY: the safety contract must be upheld by the caller unsafe { (**self).grow(ptr, layout, new_size) } } @@ -420,7 +416,7 @@ where ptr: NonNull, layout: Layout, new_size: usize, - ) -> Result { + ) -> Result, AllocErr> { // SAFETY: the safety contract must be upheld by the caller unsafe { (**self).grow_zeroed(ptr, layout, new_size) } } @@ -431,7 +427,7 @@ where ptr: NonNull, layout: Layout, new_size: usize, - ) -> Result { + ) -> Result, AllocErr> { // SAFETY: the safety contract must be upheld by the caller unsafe { (**self).shrink(ptr, layout, new_size) } } diff --git a/library/std/src/alloc.rs b/library/std/src/alloc.rs index b71a392b703..4712cc95b4a 100644 --- a/library/std/src/alloc.rs +++ b/library/std/src/alloc.rs @@ -140,7 +140,7 @@ pub struct System; #[unstable(feature = "allocator_api", issue = "32838")] unsafe impl AllocRef for System { #[inline] - fn alloc(&mut self, layout: Layout) -> Result { + fn alloc(&mut self, layout: Layout) -> Result, AllocErr> { let size = layout.size(); let ptr = if size == 0 { layout.dangling() @@ -148,11 +148,11 @@ unsafe impl AllocRef for System { // SAFETY: `layout` is non-zero in size, unsafe { NonNull::new(GlobalAlloc::alloc(&System, layout)).ok_or(AllocErr)? } }; - Ok(MemoryBlock { ptr, size }) + Ok(NonNull::slice_from_raw_parts(ptr, size)) } #[inline] - fn alloc_zeroed(&mut self, layout: Layout) -> Result { + fn alloc_zeroed(&mut self, layout: Layout) -> Result, AllocErr> { let size = layout.size(); let ptr = if size == 0 { layout.dangling() @@ -160,7 +160,7 @@ unsafe impl AllocRef for System { // SAFETY: `layout` is non-zero in size, unsafe { NonNull::new(GlobalAlloc::alloc_zeroed(&System, layout)).ok_or(AllocErr)? } }; - Ok(MemoryBlock { ptr, size }) + Ok(NonNull::slice_from_raw_parts(ptr, size)) } #[inline] @@ -178,7 +178,7 @@ unsafe impl AllocRef for System { ptr: NonNull, layout: Layout, new_size: usize, - ) -> Result { + ) -> Result, AllocErr> { debug_assert!( new_size >= layout.size(), "`new_size` must be greater than or equal to `layout.size()`" @@ -188,14 +188,16 @@ unsafe impl AllocRef for System { // Other conditions must be upheld by the caller unsafe { match layout.size() { - old_size if old_size == new_size => Ok(MemoryBlock { ptr, size: new_size }), + old_size if old_size == new_size => { + Ok(NonNull::slice_from_raw_parts(ptr, new_size)) + } 0 => self.alloc(Layout::from_size_align_unchecked(new_size, layout.align())), old_size => { // `realloc` probably checks for `new_size > size` or something similar. intrinsics::assume(new_size > old_size); let raw_ptr = GlobalAlloc::realloc(&System, ptr.as_ptr(), layout, new_size); let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?; - Ok(MemoryBlock { ptr, size: new_size }) + Ok(NonNull::slice_from_raw_parts(ptr, new_size)) } } } @@ -207,7 +209,7 @@ unsafe impl AllocRef for System { ptr: NonNull, layout: Layout, new_size: usize, - ) -> Result { + ) -> Result, AllocErr> { debug_assert!( new_size >= layout.size(), "`new_size` must be greater than or equal to `layout.size()`" @@ -217,7 +219,9 @@ unsafe impl AllocRef for System { // Other conditions must be upheld by the caller unsafe { match layout.size() { - old_size if old_size == new_size => Ok(MemoryBlock { ptr, size: new_size }), + old_size if old_size == new_size => { + Ok(NonNull::slice_from_raw_parts(ptr, new_size)) + } 0 => self.alloc_zeroed(Layout::from_size_align_unchecked(new_size, layout.align())), old_size => { // `realloc` probably checks for `new_size > size` or something similar. @@ -225,7 +229,7 @@ unsafe impl AllocRef for System { let raw_ptr = GlobalAlloc::realloc(&System, ptr.as_ptr(), layout, new_size); raw_ptr.add(old_size).write_bytes(0, new_size - old_size); let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?; - Ok(MemoryBlock { ptr, size: new_size }) + Ok(NonNull::slice_from_raw_parts(ptr, new_size)) } } } @@ -237,7 +241,7 @@ unsafe impl AllocRef for System { ptr: NonNull, layout: Layout, new_size: usize, - ) -> Result { + ) -> Result, AllocErr> { let old_size = layout.size(); debug_assert!( new_size <= old_size, @@ -264,7 +268,7 @@ unsafe impl AllocRef for System { NonNull::new(raw_ptr).ok_or(AllocErr)? }; - Ok(MemoryBlock { ptr, size: new_size }) + Ok(NonNull::slice_from_raw_parts(ptr, new_size)) } } static HOOK: AtomicPtr<()> = AtomicPtr::new(ptr::null_mut()); diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs index c81b949af65..0569e46241a 100644 --- a/library/std/src/lib.rs +++ b/library/std/src/lib.rs @@ -291,6 +291,7 @@ #![feature(negative_impls)] #![feature(never_type)] #![feature(nll)] +#![feature(nonnull_slice_from_raw_parts)] #![feature(once_cell)] #![feature(optin_builtin_traits)] #![feature(or_patterns)] @@ -308,6 +309,8 @@ #![feature(shrink_to)] #![feature(slice_concat_ext)] #![feature(slice_internals)] +#![feature(slice_ptr_get)] +#![feature(slice_ptr_len)] #![feature(slice_strip)] #![feature(staged_api)] #![feature(std_internals)] diff --git a/src/test/ui/allocator/custom.rs b/src/test/ui/allocator/custom.rs index f10d29f33fc..a6c2317c736 100644 --- a/src/test/ui/allocator/custom.rs +++ b/src/test/ui/allocator/custom.rs @@ -4,6 +4,7 @@ // no-prefer-dynamic #![feature(allocator_api)] +#![feature(slice_ptr_get)] extern crate helper; @@ -38,9 +39,9 @@ fn main() { let layout = Layout::from_size_align(4, 2).unwrap(); let memory = Global.alloc(layout.clone()).unwrap(); - helper::work_with(&memory.ptr); + helper::work_with(&memory); assert_eq!(HITS.load(Ordering::SeqCst), n + 1); - Global.dealloc(memory.ptr, layout); + Global.dealloc(memory.as_non_null_ptr(), layout); assert_eq!(HITS.load(Ordering::SeqCst), n + 2); let s = String::with_capacity(10); @@ -51,8 +52,8 @@ fn main() { let memory = System.alloc(layout.clone()).unwrap(); assert_eq!(HITS.load(Ordering::SeqCst), n + 4); - helper::work_with(&memory.ptr); - System.dealloc(memory.ptr, layout); + helper::work_with(&memory); + System.dealloc(memory.as_non_null_ptr(), layout); assert_eq!(HITS.load(Ordering::SeqCst), n + 4); } } diff --git a/src/test/ui/allocator/xcrate-use.rs b/src/test/ui/allocator/xcrate-use.rs index c7d31f71074..a1446b3664d 100644 --- a/src/test/ui/allocator/xcrate-use.rs +++ b/src/test/ui/allocator/xcrate-use.rs @@ -5,6 +5,7 @@ // no-prefer-dynamic #![feature(allocator_api)] +#![feature(slice_ptr_get)] extern crate custom; extern crate helper; @@ -21,15 +22,15 @@ fn main() { let layout = Layout::from_size_align(4, 2).unwrap(); let memory = Global.alloc(layout.clone()).unwrap(); - helper::work_with(&memory.ptr); + helper::work_with(&memory); assert_eq!(GLOBAL.0.load(Ordering::SeqCst), n + 1); - Global.dealloc(memory.ptr, layout); + Global.dealloc(memory.as_non_null_ptr(), layout); assert_eq!(GLOBAL.0.load(Ordering::SeqCst), n + 2); let memory = System.alloc(layout.clone()).unwrap(); assert_eq!(GLOBAL.0.load(Ordering::SeqCst), n + 2); - helper::work_with(&memory.ptr); - System.dealloc(memory.ptr, layout); + helper::work_with(&memory); + System.dealloc(memory.as_non_null_ptr(), layout); assert_eq!(GLOBAL.0.load(Ordering::SeqCst), n + 2); } } diff --git a/src/test/ui/realloc-16687.rs b/src/test/ui/realloc-16687.rs index e9435bb476c..bdcd47a7260 100644 --- a/src/test/ui/realloc-16687.rs +++ b/src/test/ui/realloc-16687.rs @@ -5,6 +5,7 @@ // well enough to reproduce (and illustrate) the bug from #16687. #![feature(allocator_api)] +#![feature(slice_ptr_get)] use std::alloc::{handle_alloc_error, AllocRef, Global, Layout}; use std::ptr::{self, NonNull}; @@ -41,13 +42,13 @@ unsafe fn test_triangle() -> bool { println!("allocate({:?})", layout); } - let memory = Global.alloc(layout).unwrap_or_else(|_| handle_alloc_error(layout)); + let ptr = Global.alloc(layout).unwrap_or_else(|_| handle_alloc_error(layout)); if PRINT { - println!("allocate({:?}) = {:?}", layout, memory.ptr); + println!("allocate({:?}) = {:?}", layout, ptr); } - memory.ptr.cast().as_ptr() + ptr.as_non_null_ptr().as_ptr() } unsafe fn deallocate(ptr: *mut u8, layout: Layout) { @@ -73,14 +74,14 @@ unsafe fn test_triangle() -> bool { Global.shrink(NonNull::new_unchecked(ptr), old, new.size()) }; - let memory = memory.unwrap_or_else(|_| { + let ptr = memory.unwrap_or_else(|_| { handle_alloc_error(Layout::from_size_align_unchecked(new.size(), old.align())) }); if PRINT { - println!("reallocate({:?}, old={:?}, new={:?}) = {:?}", ptr, old, new, memory.ptr); + println!("reallocate({:?}, old={:?}, new={:?}) = {:?}", ptr, old, new, ptr); } - memory.ptr.cast().as_ptr() + ptr.as_non_null_ptr().as_ptr() } fn idx_to_size(i: usize) -> usize { diff --git a/src/test/ui/regions/regions-mock-codegen.rs b/src/test/ui/regions/regions-mock-codegen.rs index 7d433530033..ad4b9c352ae 100644 --- a/src/test/ui/regions/regions-mock-codegen.rs +++ b/src/test/ui/regions/regions-mock-codegen.rs @@ -25,8 +25,8 @@ struct Ccx { fn alloc(_bcx: &arena) -> &Bcx<'_> { unsafe { let layout = Layout::new::(); - let memory = Global.alloc(layout).unwrap_or_else(|_| handle_alloc_error(layout)); - &*(memory.ptr.as_ptr() as *const _) + let ptr = Global.alloc(layout).unwrap_or_else(|_| handle_alloc_error(layout)); + &*(ptr.as_ptr() as *const _) } }