[PATCH] D60399: [CMake] Replace LLVM_ENABLE_CXX1Y and friends with LLVM_CXX_STD

[Martin Storsjö via Phabricator via llvm-commits]

mstorsjo added a comment.

In D60399#1459215 <https://reviews.llvm.org/D60399#1459215>, @phosek wrote:

> This broke all our builders that use the LLVM runtimes build with the following error:
>
>   -- Performing Test CXX_SUPPORTS_CXX_STD
>   -- Performing Test CXX_SUPPORTS_CXX_STD - Failed
>   CMake Error at /b/s/w/ir/k/llvm-project/llvm/cmake/modules/HandleLLVMOptions.cmake:451 (message):
>     The host compiler does not support '-std='.
>   Call Stack (most recent call first):
>     CMakeLists.txt:111 (include)
>  
>  
>   -- Configuring incomplete, errors occurred!
>
>
> The full log is here: https://logs.chromium.org/logs/fuchsia/buildbucket/cr-buildbucket.appspot.com/8916679531057446976/+/steps/clang/0/steps/build/0/stdout
>
> I suspect it's because we include `HandleLLVMOptions` at https://github.com/llvm/llvm-project/blob/master/llvm/runtimes/CMakeLists.txt#L111, but at that point we haven't yet compiled libc++, so any attempt to use is going to fail which is why this check is failing.


I'm looking at the same failure in my cross-bootstrap of mingw as well.

The failure isn't due to not compiling libc++ yet, but when building individual runtime projects standalone outside of the llvm tree, HandleLLVMOptions.cmake is included in that cmake project, but not the llvm main CMake file. After this change, HandleLLVMOptions.cmake adds `-std=${LLVM_CXX_STD}` to the compiler options, but nothing has set `${LLVM_CXX_STD}` yet, because the CMake file that sets it isn't included in standalone project builds.


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D60399/new/

https://reviews.llvm.org/D60399