Thanks Andrii, for detailed answer.  
Yes you are right, I'm looking for CO-RE. Basically I'm trying to build the eBPF program which can run on any linux kernel version using libbpf

What I understood from your blog https://facebookmicrosites.github.io/bpf/blog/2020/02/19/bpf-portability-and-co-re.html (Thanks for in depth blog post, appreciate it), to work libbpf based program 
the BTF information should be available on the running host. Is my understanding correct?

Btw, Is there any document to generate BTF information for a linux kernel?  Or Is there a way to generate BTF info for running kernel i.e. at runtime and not at compile time? Thanks!