// Copyright 2015 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. #![no_std] #![feature(allocator_api, rustc_private)] #![cfg_attr(any(unix, target_os = "redox"), feature(libc))] // The minimum alignment guaranteed by the architecture. This value is used to // add fast paths for low alignment values. #[cfg(all(any(target_arch = "x86", target_arch = "arm", target_arch = "mips", target_arch = "powerpc", target_arch = "powerpc64")))] const MIN_ALIGN: usize = 8; #[cfg(all(any(target_arch = "x86_64", target_arch = "aarch64", target_arch = "mips64", 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 { extern crate libc; 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 libc::c_void) } #[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 libc::c_void, 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) } } } }