Support for pkg-config

[thielema]

Bugzilla Link	9405
Version	2.8
OS	All
CC	@sylvestre

Extended Description

I would very like to have support for the pkg-config tool, since that is directly supported by Haskell's build system Cabal.

[llvmbot]

Is there no .pc file because there is no interest from the developpers or is it because no one volonteered to do it? In the latter case, I'll do it there is an interest to merge it in the source tree.

[thielema]

I came up with the following bash script that writes a pc file to stdout. The pc file addresses the LLVM shared object.

$ cat make-pkg-config.sh
version=$(llvm-config --version)

echo Name: LLVM
echo Description: Low-level Virtual Machine compiler framework

We keep the initial numeric part of a version number.

I.e. a suffix like 'svn' or 'rc' will be removed.

This way Cabal can match on version ranges.

echo Version: $(echo ${version} | sed 's/([0-9.]+).*/\1/')
echo URL: http://www.llvm.org/
echo Requires:
echo Conflicts:
echo Libs: -L$(llvm-config --libdir) -lLLVM-${version}
echo Cflags: -I$(llvm-config --includedir)

[thielema]

I have written a Haskell program that performs almost the same as the given shell script:
http://hackage.haskell.org/package/llvm-pkg-config

You may install it with
$ cabal install llvm-pkg-config

[illiliti]

Hello? Are devs still interested in supporting pkg-config or it's dead end?

[tristan957]

I think this is the right place to discuss this.

I am currently using libclang + Meson. I use libclang with the compile_commands.json that Meson generates (Awesome stuff by the way!), but I continually get errors parsing code about standard library headers not being found (fatal error: 'stdbool.h' file not found). After discovery, I have found that these headers are located in /usr/lib64/clang/14.0.5/include on my system, but for some reason libclang doesn't have this path in its automatic includes.

Yesterday I discovered that if one is using CMake to get access to libclang, libclang provides a CLANG_INCLUDE_DIRS macro which includes the aforementioned path.

It would be great if libclang could provide a pkg-config file that exposes this parameter in a build-system agnostic way.

Otherwise, I am stuck trying to parse the path from clang -Wp,-v -x c /dev/null -fsyntax-only, unless someone knows of a different way to access this path.

[tristan957]

Apparently CLANG_INCLUDE_DIRS is not what I want, what the hell...

[tstellar]

This also came up here: #58984.

[TheDSCPL]

I was about to pull my hair out over this because I couldn't get pkg-config to find libclang. I'm surprised that it doesn't export a *.pc file and that this issue has been created in 2011 (14 years ago!!!), but is still open and has no activity! It's such an easy feature, too! Just look at libevent's pkg-config template. How is this a complicated thing to add? I don't get it...