lebedev.ri added a comment. In https://reviews.llvm.org/D33826#866161, @JonasToth wrote:
> There is an exception to the general rule (EXP36-C-EX2), stating that the > result of `malloc` and friends is allowed to be casted to stricter > alignments, since the pointer is known to be of correct alignment. Quote for the reference: > EXP36-C-EX2: If a pointer is known to be correctly aligned to the target > type, then a cast to that type is permitted. There are several cases where a > pointer is known to be correctly aligned to the target type. The pointer > could point to an object declared with a suitable alignment specifier. It > could point to an object returned by aligned_alloc(), calloc(), malloc(), or > realloc(), as per the C standard, section 7.22.3, paragraph 1 [ISO/IEC > 9899:2011]. For plain `calloc(), malloc(), or realloc()`, i would guess it's related to `max_align_t` / `std::max_align_t` / `__STDCPP_DEFAULT_NEW_ALIGNMENT__`, which is generally just `16` bytes. > Could you add a testcase for this case, i think there would currenlty be a > false positive. > > And is there a general way of knowing when the pointer is of correct > alignment, or is it necessary to keep a list of functions like `malloc` that > are just known? > If yes, i think it would be nice if this list is configurable (maybe like in > cppcoreguidelines-no-malloc, where that functionality could be refactored > out). Repository: rL LLVM https://reviews.llvm.org/D33826 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
