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| 1 | +// Copyright 2015 The Rust Project Developers. See the COPYRIGHT |
| 2 | +// file at the top-level directory of this distribution and at |
| 3 | +// http://rust-lang.org/COPYRIGHT. |
| 4 | +// |
| 5 | +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| 6 | +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| 7 | +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| 8 | +// option. This file may not be copied, modified, or distributed |
| 9 | +// except according to those terms. |
| 10 | +#![no_std] |
| 11 | +#![feature(allocator_api, rustc_private)] |
| 12 | +#![cfg_attr(any(unix, target_os = "redox"), feature(libc))] |
| 13 | + |
| 14 | +// The minimum alignment guaranteed by the architecture. This value is used to |
| 15 | +// add fast paths for low alignment values. |
| 16 | +#[cfg(all(any(target_arch = "x86", |
| 17 | + target_arch = "arm", |
| 18 | + target_arch = "mips", |
| 19 | + target_arch = "powerpc", |
| 20 | + target_arch = "powerpc64")))] |
| 21 | +const MIN_ALIGN: usize = 8; |
| 22 | +#[cfg(all(any(target_arch = "x86_64", |
| 23 | + target_arch = "aarch64", |
| 24 | + target_arch = "mips64", |
| 25 | + target_arch = "s390x", |
| 26 | + target_arch = "sparc64")))] |
| 27 | +const MIN_ALIGN: usize = 16; |
| 28 | + |
| 29 | +pub struct System; |
| 30 | +#[cfg(any(windows, unix, target_os = "redox"))] |
| 31 | +mod realloc_fallback { |
| 32 | + use core::alloc::{GlobalAlloc, Layout}; |
| 33 | + use core::cmp; |
| 34 | + use core::ptr; |
| 35 | + impl super::System { |
| 36 | + pub(crate) unsafe fn realloc_fallback(&self, ptr: *mut u8, old_layout: Layout, |
| 37 | + new_size: usize) -> *mut u8 { |
| 38 | + // Docs for GlobalAlloc::realloc require this to be valid: |
| 39 | + let new_layout = Layout::from_size_align_unchecked(new_size, old_layout.align()); |
| 40 | + let new_ptr = GlobalAlloc::alloc(self, new_layout); |
| 41 | + if !new_ptr.is_null() { |
| 42 | + let size = cmp::min(old_layout.size(), new_size); |
| 43 | + ptr::copy_nonoverlapping(ptr, new_ptr, size); |
| 44 | + GlobalAlloc::dealloc(self, ptr, old_layout); |
| 45 | + } |
| 46 | + new_ptr |
| 47 | + } |
| 48 | + } |
| 49 | +} |
| 50 | +#[cfg(any(unix, target_os = "redox"))] |
| 51 | +mod platform { |
| 52 | + extern crate libc; |
| 53 | + use core::ptr; |
| 54 | + use MIN_ALIGN; |
| 55 | + use System; |
| 56 | + use core::alloc::{GlobalAlloc, Layout}; |
| 57 | + unsafe impl GlobalAlloc for System { |
| 58 | + #[inline] |
| 59 | + unsafe fn alloc(&self, layout: Layout) -> *mut u8 { |
| 60 | + if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() { |
| 61 | + libc::malloc(layout.size()) as *mut u8 |
| 62 | + } else { |
| 63 | + #[cfg(target_os = "macos")] |
| 64 | + { |
| 65 | + if layout.align() > (1 << 31) { |
| 66 | + return ptr::null_mut() |
| 67 | + } |
| 68 | + } |
| 69 | + aligned_malloc(&layout) |
| 70 | + } |
| 71 | + } |
| 72 | + #[inline] |
| 73 | + unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 { |
| 74 | + if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() { |
| 75 | + libc::calloc(layout.size(), 1) as *mut u8 |
| 76 | + } else { |
| 77 | + let ptr = self.alloc(layout.clone()); |
| 78 | + if !ptr.is_null() { |
| 79 | + ptr::write_bytes(ptr, 0, layout.size()); |
| 80 | + } |
| 81 | + ptr |
| 82 | + } |
| 83 | + } |
| 84 | + #[inline] |
| 85 | + unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) { |
| 86 | + libc::free(ptr as *mut libc::c_void) |
| 87 | + } |
| 88 | + #[inline] |
| 89 | + unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 { |
| 90 | + if layout.align() <= MIN_ALIGN && layout.align() <= new_size { |
| 91 | + libc::realloc(ptr as *mut libc::c_void, new_size) as *mut u8 |
| 92 | + } else { |
| 93 | + self.realloc_fallback(ptr, layout, new_size) |
| 94 | + } |
| 95 | + } |
| 96 | + } |
| 97 | + #[cfg(any(target_os = "android", |
| 98 | + target_os = "hermit", |
| 99 | + target_os = "redox", |
| 100 | + target_os = "solaris"))] |
| 101 | + #[inline] |
| 102 | + unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 { |
| 103 | + // On android we currently target API level 9 which unfortunately |
| 104 | + // doesn't have the `posix_memalign` API used below. Instead we use |
| 105 | + // `memalign`, but this unfortunately has the property on some systems |
| 106 | + // where the memory returned cannot be deallocated by `free`! |
| 107 | + // |
| 108 | + // Upon closer inspection, however, this appears to work just fine with |
| 109 | + // Android, so for this platform we should be fine to call `memalign` |
| 110 | + // (which is present in API level 9). Some helpful references could |
| 111 | + // possibly be chromium using memalign [1], attempts at documenting that |
| 112 | + // memalign + free is ok [2] [3], or the current source of chromium |
| 113 | + // which still uses memalign on android [4]. |
| 114 | + // |
| 115 | + // [1]: https://codereview.chromium.org/10796020/ |
| 116 | + // [2]: https://code.google.com/p/android/issues/detail?id=35391 |
| 117 | + // [3]: https://bugs.chromium.org/p/chromium/issues/detail?id=138579 |
| 118 | + // [4]: https://chromium.googlesource.com/chromium/src/base/+/master/ |
| 119 | + // /memory/aligned_memory.cc |
| 120 | + libc::memalign(layout.align(), layout.size()) as *mut u8 |
| 121 | + } |
| 122 | + #[cfg(not(any(target_os = "android", |
| 123 | + target_os = "hermit", |
| 124 | + target_os = "redox", |
| 125 | + target_os = "solaris")))] |
| 126 | + #[inline] |
| 127 | + unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 { |
| 128 | + let mut out = ptr::null_mut(); |
| 129 | + let ret = libc::posix_memalign(&mut out, layout.align(), layout.size()); |
| 130 | + if ret != 0 { |
| 131 | + ptr::null_mut() |
| 132 | + } else { |
| 133 | + out as *mut u8 |
| 134 | + } |
| 135 | + } |
| 136 | +} |
| 137 | +#[cfg(windows)] |
| 138 | +#[allow(nonstandard_style)] |
| 139 | +mod platform { |
| 140 | + use MIN_ALIGN; |
| 141 | + use System; |
| 142 | + use core::alloc::{GlobalAlloc, Layout}; |
| 143 | + type LPVOID = *mut u8; |
| 144 | + type HANDLE = LPVOID; |
| 145 | + type SIZE_T = usize; |
| 146 | + type DWORD = u32; |
| 147 | + type BOOL = i32; |
| 148 | + extern "system" { |
| 149 | + fn GetProcessHeap() -> HANDLE; |
| 150 | + fn HeapAlloc(hHeap: HANDLE, dwFlags: DWORD, dwBytes: SIZE_T) -> LPVOID; |
| 151 | + fn HeapReAlloc(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID, dwBytes: SIZE_T) -> LPVOID; |
| 152 | + fn HeapFree(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID) -> BOOL; |
| 153 | + fn GetLastError() -> DWORD; |
| 154 | + } |
| 155 | + #[repr(C)] |
| 156 | + struct Header(*mut u8); |
| 157 | + const HEAP_ZERO_MEMORY: DWORD = 0x00000008; |
| 158 | + unsafe fn get_header<'a>(ptr: *mut u8) -> &'a mut Header { |
| 159 | + &mut *(ptr as *mut Header).offset(-1) |
| 160 | + } |
| 161 | + unsafe fn align_ptr(ptr: *mut u8, align: usize) -> *mut u8 { |
| 162 | + let aligned = ptr.add(align - (ptr as usize & (align - 1))); |
| 163 | + *get_header(aligned) = Header(ptr); |
| 164 | + aligned |
| 165 | + } |
| 166 | + #[inline] |
| 167 | + unsafe fn allocate_with_flags(layout: Layout, flags: DWORD) -> *mut u8 { |
| 168 | + let ptr = if layout.align() <= MIN_ALIGN { |
| 169 | + HeapAlloc(GetProcessHeap(), flags, layout.size()) |
| 170 | + } else { |
| 171 | + let size = layout.size() + layout.align(); |
| 172 | + let ptr = HeapAlloc(GetProcessHeap(), flags, size); |
| 173 | + if ptr.is_null() { |
| 174 | + ptr |
| 175 | + } else { |
| 176 | + align_ptr(ptr, layout.align()) |
| 177 | + } |
| 178 | + }; |
| 179 | + ptr as *mut u8 |
| 180 | + } |
| 181 | + unsafe impl GlobalAlloc for System { |
| 182 | + #[inline] |
| 183 | + unsafe fn alloc(&self, layout: Layout) -> *mut u8 { |
| 184 | + allocate_with_flags(layout, 0) |
| 185 | + } |
| 186 | + #[inline] |
| 187 | + unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 { |
| 188 | + allocate_with_flags(layout, HEAP_ZERO_MEMORY) |
| 189 | + } |
| 190 | + #[inline] |
| 191 | + unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) { |
| 192 | + if layout.align() <= MIN_ALIGN { |
| 193 | + let err = HeapFree(GetProcessHeap(), 0, ptr as LPVOID); |
| 194 | + debug_assert!(err != 0, "Failed to free heap memory: {}", |
| 195 | + GetLastError()); |
| 196 | + } else { |
| 197 | + let header = get_header(ptr); |
| 198 | + let err = HeapFree(GetProcessHeap(), 0, header.0 as LPVOID); |
| 199 | + debug_assert!(err != 0, "Failed to free heap memory: {}", |
| 200 | + GetLastError()); |
| 201 | + } |
| 202 | + } |
| 203 | + #[inline] |
| 204 | + unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 { |
| 205 | + if layout.align() <= MIN_ALIGN { |
| 206 | + HeapReAlloc(GetProcessHeap(), 0, ptr as LPVOID, new_size) as *mut u8 |
| 207 | + } else { |
| 208 | + self.realloc_fallback(ptr, layout, new_size) |
| 209 | + } |
| 210 | + } |
| 211 | + } |
| 212 | +} |
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