Merge branch 'bpftool-visualization'

Jakub Kicinski says:

====================
Jiong says:

This patch set is an application of CFG information on eBPF program
visualization. It presents some initial code for building CFG information
from eBPF instruction sequences.

After we get eBPF program bytecode, we do sub-program detection and
basic-block partition. These information then are visualized into DOT
graph.

The user could use any DOT graphic tools (xdot, graphviz etc) to view it.

For example:

  bpftool prog dump xlated id 2 visual &>output.dot

  [xdot | dotty] output.dot
  dot -Tpng -o output.png

This initial patch set hasn't tuned much on the dot description layout
nor decoration, we could improve them later once the direction of the patch
set is agreed on. We could also visualize some static analysis performance
data.

v2 (Jakub):
 - update license headers and add SPDX tags.
====================

Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>