llvm dev - May 2020 - OpenMP Error in Clang

Hello,

I am getting the following error while trying to build a benchmark with a custom
function pass:

clang  -Xclang -fopenmp=libomp -Xclang -load -Xclang my_lib.so file.c


 error: unknown argument: '-fopenmp=libomp'

If I use this instead:

clang  -Xclang -fopenmp=libomp -Xclang -load -Xclang my_lib.so file.c

I get the error:  fatal error: 'omp.h' file not found

I am not sure where the problem is, especially since I have used OpenMP
applications with llvm before.

Thanks,
Bodhi
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I don't see what the difference is between the two command lines is.
However,

1. the option is "clang -fopenmp" (without -Xclang, which is for
options for the -cc1 invocation)

2. omp.h is part of the openmp subproject, it must be enabled
(-DLLVM_ENABLE_PROJECTS=openmp) and omp.h found in the include path.

Michael


Am Di., 26. Mai 2020 um 20:29 Uhr schrieb Chatterjee, Bodhisatwa via
llvm-dev <llvm-dev at lists.llvm.org>:
>
> Hello,
>
> I am getting the following error while trying to build a benchmark with a
custom function pass:
>
> clang  -Xclang -fopenmp=libomp -Xclang -load -Xclang my_lib.so file.c
>
>
>  error: unknown argument: '-fopenmp=libomp'
>
> If I use this instead:
>
> clang  -Xclang -fopenmp=libomp -Xclang -load -Xclang my_lib.so file.c
>
> I get the error:  fatal error: 'omp.h' file not found
>
> I am not sure where the problem is, especially since I have used OpenMP
applications with llvm before.
>
> Thanks,
> Bodhi
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

On 5/27/20 5:44 AM, Michael Kruse via llvm-dev wrote:
> I don't see what the difference is between the two command lines is.
However,
Me neither.

> 1. the option is "clang -fopenmp" (without -Xclang, which is for
> options for the -cc1 invocation)
Right. If you don't use the driver option you need to manage your 
include and library paths yourself.

Does `clang -fopenmp test.c` work for you?

>
> 2. omp.h is part of the openmp subproject, it must be enabled
> (-DLLVM_ENABLE_PROJECTS=openmp) and omp.h found in the include path.
>
> Michael
>
>
> Am Di., 26. Mai 2020 um 20:29 Uhr schrieb Chatterjee, Bodhisatwa via
> llvm-dev <llvm-dev at lists.llvm.org>:
>> Hello,
>>
>> I am getting the following error while trying to build a benchmark with
a custom function pass:
>>
>> clang  -Xclang -fopenmp=libomp -Xclang -load -Xclang my_lib.so file.c
>>
>>
>>   error: unknown argument: '-fopenmp=libomp'
>>
>> If I use this instead:
>>
>> clang  -Xclang -fopenmp=libomp -Xclang -load -Xclang my_lib.so file.c
>>
>> I get the error:  fatal error: 'omp.h' file not found
>>
>> I am not sure where the problem is, especially since I have used OpenMP
applications with llvm before.
>>
>> Thanks,
>> Bodhi
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev