RFE: Make semcode understand function pointers

[jsitnicki]

semcode will not report any callers if a function gets called only through a function pointer:

Example:

semcode> callers tcp_v4_rcv
Finding all functions that call: tcp_v4_rcv
Info: No functions call 'tcp_v4_rcv'
semcode>

It would be awesome if semcode callers could look for any designated initializers for structures where a function is referenced, a common pattern in the kernel. Then follow up with search for any calls of the function pointer field for that structure type. It would probably result in false positives in some cases, but the user can audit the call sites manually.

In our example that is:

*** net/ipv4/af_inet.c:
inet_init[1943]                .handler = tcp_v4_rcv,

*** net/ipv4/ip_input.c:
ip_protocol_deliver_rcu[207]   ret = INDIRECT_CALL_2(ipprot->handler, tcp_v4_rcv, udp_rcv,

That would really set it apart from classic cross-referencers like cscope. I realize this is probably a hard problem or out of scope :-)

[masoncl]

I think this is probably somewhere that sparse and smatch are better than tree-sitter. But I'll definitely look into it, I think the next step up in quality will come from being able to do these kinds of analysis.