[LLVMdev] clean CMake build failing (Mac OS X 10.8)

[Marshall Clow]

On Jul 30, 2012, at 10:03 AM, Marshall Clow <mclow.lists at gmail.com> wrote:

> Over the weekend I upgraded my system to Mac OS X 10.8, and now a clean cmake build fails.
> 
> The error message:
>> Building C object runtime/libprofile/CMakeFiles/profile_rt-static.dir/CommonProfiling.c.o
>> cc1: error: unrecognized command line option "-Wcovered-switch-default"
> 
> 
> The configuration:
>> Mac OS X 10.8
>> CMake 2.8.8
>> LLVM tot
>> Apple clang version 4.0 (tags/Apple/clang-421.0.57) (based on LLVM 3.1svn)
> 
> 
> Running cmake to generate the make files gives the following output:
>> -- The C compiler identification is GNU 4.2.1
>> -- The CXX compiler identification is Clang 4.0.0
>> 
> 
> Diagnosis:
> cmake is passing "-Wcovered-switch-default" to the c compiler.
> It also thinks that the c compiler should be gcc, rather than clang.
> gcc does not support that switch, and fails.
> 
> Possible solutions:
> * use clang to compile the C code  (note that /usr/bin/cc is clang on this system; why it's picking gcc, I don't know)
> * Don't pass "-Wcovered-switch-default" to the C compiler.

A workaround - force use of clang for C compilations:
	CC=/usr/bin/cc cmake $LLVM/llvm

-- Marshall

Marshall Clow     Idio Software   <mailto:mclow.lists at gmail.com>

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