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

[Fangrui Song via Phabricator via cfe-commits]

MaskRay added inline comments.


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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@"
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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.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D131465/new/

https://reviews.llvm.org/D131465