Comment # 11 on bug 1231247 from Aaron Puchert

(In reply to Aaron Puchert from comment #10)
> Internal headers are probably used to get the layout of certain data
> structures.

Which is probably because bcc predates BPF CO-RE (Compile Once – Run
Everywhere).

The newer bpftrace with CO-RE doesn't use Clang but BPF Type Format (BTF) to
find the right offsets.

> I think it predates the BPF backend in GCC.

LWN wrote about this last month (https://lwn.net/Articles/990343/):

> The generation of binary code for the kernel's BPF virtual machine has been
> limited to the Clang compiler since the beginning; even developers who use
> GCC to build kernels must use Clang to compile to BPF. Work has been underway
> for some years on adding a BPF backend to GCC as well; the developers
> involved ran a session at the 2024 GNU Tools Cauldron to provide an update
> on that project. It would seem that the BPF backend is close to being ready
> for production use.

So it's probably still a bit too fresh for other projects to support it.