EricWF added a comment. In https://reviews.llvm.org/D45015#1127046, @vsapsai wrote:
> In https://reviews.llvm.org/D45015#1121762, @EricWF wrote: > > > In https://reviews.llvm.org/D45015#1121581, @ahatanak wrote: > > > > > Could you elaborate on what kind of changes you are planning to make in > > > libc++ after committing this patch? > > > > > > Libc++ shouldn't actually need any changes if this current patch lands. > > Currently libc++ is in a "incorrect" state where > > it generates calls to `__builtin_operator_new(size_t, align_val_t)` when > > `__cpp_aligned_new` is defined but when aligned new/delete > > are actually unavailable. > > > > If we change `__cpp_aligned_new` to no longer be defined when aligned new > > is unavailable, then libc++ will start doing the right thing. > > See r328180 > > <https://github.com/llvm-mirror/libcxx/commit/a83128739983c83eaf1ba4c2bc0e3aa570082d15#diff-bd538fe75403fdbc4de9a1b97bc7c283> > > for the relevent commits which made these libc++ changes. > > > Looks like in libc++ we need to remove `_LIBCPP_STD_VER` check for aligned > allocations, something like > > #if !defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION) && \ > - (!(defined(_LIBCPP_BUILDING_NEW) || _LIBCPP_STD_VER > 14 || \ > + (!(defined(_LIBCPP_BUILDING_NEW) || \ > (defined(__cpp_aligned_new) && __cpp_aligned_new >= 201606))) > # define _LIBCPP_HAS_NO_ALIGNED_ALLOCATION > #endif > > > Is that correct? I didn't check the rest of the code, probably > TEST_HAS_NO_ALIGNED_ALLOCATION needs some clean up too. Huh, that original formulation is correct-ish, and so is your proposed changes. There are two problems here: 1. We want to expose the aligned allocation declarations to users in C++17, even if the compiler will never call them because the feature has been disabled. 2. We don't want to generate calls to them via `__builtin_operator_new` when we've only enabled the declarations because of C++17. I'll make some changes to libc++ to address this. Thanks for pointing it out. https://reviews.llvm.org/D45015 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
