diff --git a/src/liballoc_system/lib.rs b/src/liballoc_system/lib.rs index a22299c5e1a54..9eade937bfb4c 100644 --- a/src/liballoc_system/lib.rs +++ b/src/liballoc_system/lib.rs @@ -80,13 +80,40 @@ mod imp { if align <= MIN_ALIGN { libc::malloc(size as libc::size_t) as *mut u8 } else { - let mut out = ptr::null_mut(); - let ret = libc::posix_memalign(&mut out, align as libc::size_t, size as libc::size_t); - if ret != 0 { - ptr::null_mut() - } else { - out as *mut u8 - } + aligned_malloc(size, align) + } + } + + #[cfg(target_os = "android")] + unsafe fn aligned_malloc(size: usize, align: usize) -> *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(align as libc::size_t, size as libc::size_t) as *mut u8 + } + + #[cfg(not(target_os = "android"))] + unsafe fn aligned_malloc(size: usize, align: usize) -> *mut u8 { + let mut out = ptr::null_mut(); + let ret = libc::posix_memalign(&mut out, align as libc::size_t, size as libc::size_t); + if ret != 0 { + ptr::null_mut() + } else { + out as *mut u8 } }