[PATCH] D131465: C++/ObjC++: switch to gnu++17 as the default standard

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman accepted this revision.
aaron.ballman added a comment.
This revision is now accepted and ready to land.

In D131465#3772803 <https://reviews.llvm.org/D131465#3772803>, @MaskRay wrote:

> Update clang-tools-extra/clangd/unittests/SelectionTests.cpp @sammccall

This one looks to still be failing on Windows according to precommit CI.

Otherwise, the changes LGTM



================
Comment at: clang/test/lit.site.cfg.py.in:27
 config.clang_enable_opaque_pointers = @CLANG_ENABLE_OPAQUE_POINTERS_INTERNAL@
+config.clang_default_std_cxx = "@CLANG_DEFAULT_STD_CXX@"
 config.clang_default_cxx_stdlib = "@CLANG_DEFAULT_CXX_STDLIB@"
----------------
MaskRay wrote:
> aaron.ballman wrote:
> > MaskRay wrote:
> > > aaron.ballman wrote:
> > > > Should we add some documentation for this in a follow-up? (I know `CLANG_DEFAULT_STD_CXX` already exists, but it seems like it'd be helpful to tell users about it too.)
> > > Where shall we place the documentation? My understanding is that we don't document lit.* config changes.
> > > 
> > > Personally I think we probably should get rid of `CLANG_DEFAULT_STD_CXX` (D34365 @mgorny), which may require improvements to Clang configuration file (https://discourse.llvm.org/t/configuration-files/42529 https://clang.llvm.org/docs/UsersManual.html#configuration-files).
> > Oh, I thought this was a CMake variable that users could set, so I was thinking it would have gone into https://llvm.org/docs/CMake.html#rarely-used-cmake-variables. Is this not something users set to try test out in a different language standard mode than the default?
> AIUI we currently document none of `CLANG_*` cmake variables, because we don't have a Clang counterpart of  `llvm/docs/CMake.rst`.
> 
> For `CLANG_DEFAULT_STD_CXX`, I decide to remove it in D133375. But this patch has to add minimum test support to make tests pass when it is still present.
> AIUI we currently document none of CLANG_* cmake variables, because we don't have a Clang counterpart of llvm/docs/CMake.rst.

Yup, we should definitely address that at some point (not part of this patch).

> For CLANG_DEFAULT_STD_CXX, I decide to remove it in D133375. But this patch has to add minimum test support to make tests pass when it is still present.

Okay, we can discuss the removal over there, thanks for the info!


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https://reviews.llvm.org/D131465