[Openmp-commits] [PATCH] D40081: [CMake] Refactor common settings and flags

[Jonathan Peyton via Phabricator via Openmp-commits]

jlpeyton added inline comments.


================
Comment at: libomptarget/CMakeLists.txt:47-49
 # We need C++11 support.
-if(LIBOMPTARGET_HAVE_STD_CPP11_FLAG)
+if(OPENMP_HAVE_STD_CPP11_FLAG)
   
----------------
While we are cleaning up... I think this would be cleaner if all prerequisites were checked here and an error issued if one is not met.  Currently there seems to be only one (need -std=c++11 flag)  I don't think it would hurt to check for users trying to build on mac or windows here either and issue a similar message, because that would mean they tried to improperly override OPENMP_ENABLE_LIBOMPTARGET

```
# Check prerequisites for building libomptarget
if (NOT OPENMP_HAVE_STD_CPP11_FLAG)
  libomptarget_error_say("Requested build of libomptarget with no -std=c++11 flag")
endif()
```

You could also add OPENMP_HAVE_STD_CPP11_FLAG into the logic which determines the default ENABLE_LIBOMPTARGET inside the top-level CMakeLists.txt file.

If a user somehow finds them self inside the libomptarget/CMakeLists.txt file without -std=c++11 flag support.  I think its better for CMake to scream at the user during config time rather than for a status message to get lost in a sea of CMake output, because then the user builds all of LLVM and they scratch their heads trying to find libomptarget.


https://reviews.llvm.org/D40081