| // SPDX-License-Identifier: MIT OR Apache-2.0 |
| // SPDX-FileCopyrightText: The Rust Project Developers (see https://thanks.rust-lang.org) |
| |
| #![no_std] |
| #![feature(allocator_api, rustc_private)] |
| |
| // The minimum alignment guaranteed by the architecture. This value is used to |
| // add fast paths for low alignment values. |
| #[cfg(any(target_arch = "x86", |
| target_arch = "arm", |
| target_arch = "m68k", |
| target_arch = "mips", |
| target_arch = "mips32r6", |
| target_arch = "powerpc", |
| target_arch = "csky", |
| target_arch = "powerpc64"))] |
| const MIN_ALIGN: usize = 8; |
| #[cfg(any(target_arch = "x86_64", |
| target_arch = "aarch64", |
| target_arch = "loongarch64", |
| target_arch = "mips64", |
| target_arch = "mips64r6", |
| target_arch = "s390x", |
| target_arch = "sparc64"))] |
| const MIN_ALIGN: usize = 16; |
| |
| pub struct System; |
| #[cfg(any(windows, unix, target_os = "redox"))] |
| mod realloc_fallback { |
| use core::alloc::{GlobalAlloc, Layout}; |
| use core::cmp; |
| use core::ptr; |
| impl super::System { |
| pub(crate) unsafe fn realloc_fallback(&self, ptr: *mut u8, old_layout: Layout, |
| new_size: usize) -> *mut u8 { |
| // Docs for GlobalAlloc::realloc require this to be valid: |
| let new_layout = Layout::from_size_align_unchecked(new_size, old_layout.align()); |
| let new_ptr = GlobalAlloc::alloc(self, new_layout); |
| if !new_ptr.is_null() { |
| let size = cmp::min(old_layout.size(), new_size); |
| ptr::copy_nonoverlapping(ptr, new_ptr, size); |
| GlobalAlloc::dealloc(self, ptr, old_layout); |
| } |
| new_ptr |
| } |
| } |
| } |
| #[cfg(any(unix, target_os = "redox"))] |
| mod platform { |
| mod libc { |
| use core::ffi::{c_void, c_int}; |
| |
| #[link(name = "c")] |
| extern "C" { |
| pub fn malloc(size: usize) -> *mut c_void; |
| pub fn realloc(ptr: *mut c_void, size: usize) -> *mut c_void; |
| pub fn calloc(nmemb: usize, size: usize) -> *mut c_void; |
| pub fn free(ptr: *mut u8); |
| pub fn posix_memalign(memptr: *mut *mut c_void, alignment: usize, size: usize) -> c_int; |
| } |
| } |
| use core::ptr; |
| use MIN_ALIGN; |
| use System; |
| use core::alloc::{GlobalAlloc, Layout}; |
| unsafe impl GlobalAlloc for System { |
| #[inline] |
| unsafe fn alloc(&self, layout: Layout) -> *mut u8 { |
| if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() { |
| libc::malloc(layout.size()) as *mut u8 |
| } else { |
| #[cfg(target_os = "macos")] |
| { |
| if layout.align() > (1 << 31) { |
| return ptr::null_mut() |
| } |
| } |
| aligned_malloc(&layout) |
| } |
| } |
| #[inline] |
| unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 { |
| if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() { |
| libc::calloc(layout.size(), 1) as *mut u8 |
| } else { |
| let ptr = self.alloc(layout.clone()); |
| if !ptr.is_null() { |
| ptr::write_bytes(ptr, 0, layout.size()); |
| } |
| ptr |
| } |
| } |
| #[inline] |
| unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) { |
| libc::free(ptr as *mut _) |
| } |
| #[inline] |
| unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 { |
| if layout.align() <= MIN_ALIGN && layout.align() <= new_size { |
| libc::realloc(ptr as *mut _, new_size) as *mut u8 |
| } else { |
| self.realloc_fallback(ptr, layout, new_size) |
| } |
| } |
| } |
| #[cfg(any(target_os = "android", |
| target_os = "hermit", |
| target_os = "redox", |
| target_os = "solaris"))] |
| #[inline] |
| unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 { |
| // On android we currently target API level 9 which unfortunately |
| // doesn't have the `posix_memalign` API used below. Instead we use |
| // `memalign`, but this unfortunately has the property on some systems |
| // where the memory returned cannot be deallocated by `free`! |
| // |
| // Upon closer inspection, however, this appears to work just fine with |
| // Android, so for this platform we should be fine to call `memalign` |
| // (which is present in API level 9). Some helpful references could |
| // possibly be chromium using memalign [1], attempts at documenting that |
| // memalign + free is ok [2] [3], or the current source of chromium |
| // which still uses memalign on android [4]. |
| // |
| // [1]: https://codereview.chromium.org/10796020/ |
| // [2]: https://code.google.com/p/android/issues/detail?id=35391 |
| // [3]: https://bugs.chromium.org/p/chromium/issues/detail?id=138579 |
| // [4]: https://chromium.googlesource.com/chromium/src/base/+/master/ |
| // /memory/aligned_memory.cc |
| libc::memalign(layout.align(), layout.size()) as *mut u8 |
| } |
| #[cfg(not(any(target_os = "android", |
| target_os = "hermit", |
| target_os = "redox", |
| target_os = "solaris")))] |
| #[inline] |
| unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 { |
| let mut out = ptr::null_mut(); |
| let ret = libc::posix_memalign(&mut out, layout.align(), layout.size()); |
| if ret != 0 { |
| ptr::null_mut() |
| } else { |
| out as *mut u8 |
| } |
| } |
| } |
| #[cfg(windows)] |
| #[allow(nonstandard_style)] |
| mod platform { |
| use MIN_ALIGN; |
| use System; |
| use core::alloc::{GlobalAlloc, Layout}; |
| type LPVOID = *mut u8; |
| type HANDLE = LPVOID; |
| type SIZE_T = usize; |
| type DWORD = u32; |
| type BOOL = i32; |
| extern "system" { |
| fn GetProcessHeap() -> HANDLE; |
| fn HeapAlloc(hHeap: HANDLE, dwFlags: DWORD, dwBytes: SIZE_T) -> LPVOID; |
| fn HeapReAlloc(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID, dwBytes: SIZE_T) -> LPVOID; |
| fn HeapFree(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID) -> BOOL; |
| fn GetLastError() -> DWORD; |
| } |
| #[repr(C)] |
| struct Header(*mut u8); |
| const HEAP_ZERO_MEMORY: DWORD = 0x00000008; |
| unsafe fn get_header<'a>(ptr: *mut u8) -> &'a mut Header { |
| &mut *(ptr as *mut Header).sub(1) |
| } |
| unsafe fn align_ptr(ptr: *mut u8, align: usize) -> *mut u8 { |
| let aligned = ptr.add(align - (ptr as usize & (align - 1))); |
| *get_header(aligned) = Header(ptr); |
| aligned |
| } |
| #[inline] |
| unsafe fn allocate_with_flags(layout: Layout, flags: DWORD) -> *mut u8 { |
| let ptr = if layout.align() <= MIN_ALIGN { |
| HeapAlloc(GetProcessHeap(), flags, layout.size()) |
| } else { |
| let size = layout.size() + layout.align(); |
| let ptr = HeapAlloc(GetProcessHeap(), flags, size); |
| if ptr.is_null() { |
| ptr |
| } else { |
| align_ptr(ptr, layout.align()) |
| } |
| }; |
| ptr as *mut u8 |
| } |
| unsafe impl GlobalAlloc for System { |
| #[inline] |
| unsafe fn alloc(&self, layout: Layout) -> *mut u8 { |
| allocate_with_flags(layout, 0) |
| } |
| #[inline] |
| unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 { |
| allocate_with_flags(layout, HEAP_ZERO_MEMORY) |
| } |
| #[inline] |
| unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) { |
| if layout.align() <= MIN_ALIGN { |
| let err = HeapFree(GetProcessHeap(), 0, ptr as LPVOID); |
| debug_assert!(err != 0, "Failed to free heap memory: {}", |
| GetLastError()); |
| } else { |
| let header = get_header(ptr); |
| let err = HeapFree(GetProcessHeap(), 0, header.0 as LPVOID); |
| debug_assert!(err != 0, "Failed to free heap memory: {}", |
| GetLastError()); |
| } |
| } |
| #[inline] |
| unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 { |
| if layout.align() <= MIN_ALIGN { |
| HeapReAlloc(GetProcessHeap(), 0, ptr as LPVOID, new_size) as *mut u8 |
| } else { |
| self.realloc_fallback(ptr, layout, new_size) |
| } |
| } |
| } |
| } |
