strengthen aligment guarantee (issue #206) (reverse commit 4531367)

This commit is contained in:
daan 2020-02-17 09:15:48 -08:00
parent 3e198cc87d
commit 16ebb70e4c

View file

@ -20,8 +20,7 @@ static void* mi_heap_malloc_zero_aligned_at(mi_heap_t* const heap, const size_t
mi_assert(alignment > 0 && alignment % sizeof(void*) == 0);
if (mi_unlikely(size > PTRDIFF_MAX)) return NULL; // we don't allocate more than PTRDIFF_MAX (see <https://sourceware.org/ml/libc-announce/2019/msg00001.html>)
if (mi_unlikely(alignment==0 || !_mi_is_power_of_two(alignment))) return NULL; // require power-of-two (see <https://en.cppreference.com/w/c/memory/aligned_alloc>)
if (alignment <= MI_MAX_ALIGN_SIZE && offset==0) return _mi_heap_malloc_zero(heap, size, zero);
if (mi_unlikely(alignment==0 || !_mi_is_power_of_two(alignment))) return NULL; // require power-of-two (see <https://en.cppreference.com/w/c/memory/aligned_alloc>)
const uintptr_t align_mask = alignment-1; // for any x, `(x & align_mask) == (x % alignment)`
// try if there is a small block available with just the right alignment