Looking for static analysis tool to generate call graphs

[Robert Watson]

I'd like to generate static call graphs from sections of src/sys/kern,
src/sys/net, and src/sys/netinet, and ideally, get an output that looks
pretty when printed to a (perhaps large) piece of paper.  It doesn't need
to be able to handle function pointer magic in structures (vnode
operations, socket operations, file descriptor operations, sysinits, etc); 
I just want a fairly high-level graph to get a feel for particular chunks
of code spanning a couple of C files.  Anyone have any recommendations? 
Preferably something that can actually parse the variant of C we use in
our kernel :-). 

Thanks,

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert at fledge.watson.org      Senior Research Scientist, McAfee Research