[PATCH] D50344: [libc++] Enable aligned allocation based on feature test macro, irrespective of standard

[Volodymyr Sapsai via Phabricator via cfe-commits]

vsapsai accepted this revision.
vsapsai added inline comments.
This revision is now accepted and ready to land.


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Comment at: libcxx/include/new:111-116
 #if !__has_builtin(__builtin_operator_new) || \
    __has_builtin(__builtin_operator_new) < 201802L || \
    defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION) || \
    !defined(__cpp_aligned_new) || __cpp_aligned_new < 201606
 #define _LIBCPP_HAS_NO_BUILTIN_ALIGNED_OPERATOR_NEW_DELETE
 #endif
----------------
ldionne wrote:
> vsapsai wrote:
> > Maybe move this to `__config` too? This way we'll have `__cpp_aligned_new`-related macros together.
> The big difference is that `_LIBCPP_HAS_NO_BUILTIN_ALIGNED_OPERATOR_NEW_DELETE` is only used in `<new>`, whereas `_LIBCPP_HAS_NO_ALIGNED_ALLOCATION` was used in other files as well. Hence, I feel like it makes more sense to lift `_LIBCPP_HAS_NO_ALIGNED_ALLOCATION` into `<__config>`, but not `_LIBCPP_HAS_NO_BUILTIN_ALIGNED_OPERATOR_NEW_DELETE `.
Agree with your reasoning.


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Comment at: libcxx/test/libcxx/memory/aligned_allocation_macro.pass.cpp:11
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+// XFAIL: with_system_cxx_lib=macosx10.12
+// XFAIL: with_system_cxx_lib=macosx10.11
----------------
ldionne wrote:
> vsapsai wrote:
> > Initially `with_system_cxx_lib` made me suspicious because macro `_LIBCPP_HAS_NO_ALIGNED_ALLOCATION` doesn't need specific dylib. And `XFAIL: availability=macosx10.12` seems to be working.
> > 
> > [Documentation](https://github.com/llvm-mirror/libcxx/blob/master/docs/DesignDocs/AvailabilityMarkup.rst#testing) describes which feature should be used in different cases but in this case I cannot definitely say if test uses unavailable feature. I think it is acceptable to stick with `with_system_cxx_lib` but I decided to brought to your attention the alternative.
> My understanding is that the `availability` feature may not be there if we're not using availability macros, since they can be disabled entirely.
`availability` feature [will be present](https://github.com/llvm-mirror/libcxx/blob/5428c6b9d64dd4cc65fd5665c977c11dc6f8a547/utils/libcxx/test/config.py#L403-L426) when tests are invoked with `use_system_cxx_lib`. I suspect in this case both `with_system_cxx_lib` and `availability` will work, so let's keep `with_system_cxx_lib`.


Repository:
  rCXX libc++

https://reviews.llvm.org/D50344