This module is a copy from the original folder of the llvm-project. I did not copy the folder of the github repo but from my local llvm build which is on LLVM version 12.0.0 so don't expect it to work on newer versions. I only added some additional functionality (namely irreader.go) which was missing for me.
I may extend this module in the future.
To build a project which uses this module you should use the provided build.sh file. It sets up some environment variables for the cgo bindings. You need to have llvm-config.exe in your PATH (or modify build.sh to point to your local llvm-config.exe)
You can use open.sh in the same way to open the project in VSCode without getting cgo include errors.