New submission from Petr Viktorin <encu...@gmail.com>:
malloc() returns memory that's "suitably aligned for any built-in type". All of Python's allocation functions should do the same. In bpo-27987 (PR-12850, PR-13336), the alignment was raised* to 16 bytes and `long double`. This is OK for current architectures, so there is no practical issue right now. But, C11 defines a [max_align_t] type which sounds like the *correct* thing to use for determining pymalloc/PyGC_Head alignment. At least we should assert that obmalloc's ALIGNMENT is a multiple of `alignof(max_align_t)`, and use max_align_t rather than `long double` in PyGC_Head. See also this python-cffi issue: https://foss.heptapod.net/pypy/cffi/-/issues/531#note_181779 [max_align_t]: https://en.cppreference.com/w/c/types/max_align_t * (on 64-bit arches) ---------- components: C API messages: 416421 nosy: methane, petr.viktorin, pitrou, vstinner priority: normal severity: normal status: open title: pymalloc should align to max_align_t _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue47179> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
