[CMake] Add hack to find LLVM's OpenMP with GCC #984
Conversation
| # On Fedora, it's at the same place as others, so we don't need to look elsewhere | ||
| # On Ubuntu, it's in /usr/lib/llvm-${version}, so find_package finds GOMP for GCC instead. | ||
| execute_process ( | ||
| COMMAND bash -c "for lib in $(clang -lomp -### 2>&1); do echo $lib | grep -o \"\\/.*llvm.*\\w\"; done" |
There was a problem hiding this comment.
It seem to not work as expected.
I tired running for lib in $(clang -lomp -### 2>&1); do echo $lib | grep -o \"\\/.*llvm.*\\w\"; done on both Ubuntu 22.04 and 24.04. I'm trying in docker: docker run -it ubuntu:22.04 /bin/bash. The only thing I do is apt update; apt install clang libomp-dev
On Ubuntu 22.04, I see that clang -lomp -### has "-L/usr/lib/llvm-14/bin/../lib" in it's output, but grep still doesn't catch it. On Ubuntu 24.04 there are no directories with llvm in it in clang's output.
There was a problem hiding this comment.
Thanks for checking!
My idea here is that, if libomp is in a "standard" directory (ex. /lib64), we don't need to add the extra library path. But if it's in an "LLVM specific" directory, we do. So, if clang adds any "LLVM specific" directory, we do, too.
So, even if the command line above doesn't find anything, it's still possible that we can continue to build with GCC as hoped.
rengolin
added
enhancement
This should replace #960.
It worked on my Ubuntu for both Clang and GCC.
@dbabokin please check that this works for you, too.
Fixes #959.