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>

tools/bpf/bpftool/Documentation/bpftool-prog.rst

@@ -21,7 +21,7 @@ MAP COMMANDS
 =============
 
 |	**bpftool** **prog { show | list }** [*PROG*]
-|	**bpftool** **prog dump xlated** *PROG* [{**file** *FILE* | **opcodes**}]
+|	**bpftool** **prog dump xlated** *PROG* [{**file** *FILE* | **opcodes** | **visual**}]
 |	**bpftool** **prog dump jited**  *PROG* [{**file** *FILE* | **opcodes**}]
 |	**bpftool** **prog pin** *PROG* *FILE*
 |	**bpftool** **prog load** *OBJ* *FILE*
@@ -39,12 +39,18 @@ DESCRIPTION
 		  Output will start with program ID followed by program type and
 		  zero or more named attributes (depending on kernel version).
 
-	**bpftool prog dump xlated** *PROG* [{ **file** *FILE* | **opcodes** }]
-		  Dump eBPF instructions of the program from the kernel.
-		  If *FILE* is specified image will be written to a file,
-		  otherwise it will be disassembled and printed to stdout.
+	**bpftool prog dump xlated** *PROG* [{ **file** *FILE* | **opcodes** | **visual** }]
+		  Dump eBPF instructions of the program from the kernel. By
+		  default, eBPF will be disassembled and printed to standard
+		  output in human-readable format. In this case, **opcodes**
+		  controls if raw opcodes should be printed as well.
 
-		  **opcodes** controls if raw opcodes will be printed.
+		  If **file** is specified, the binary image will instead be
+		  written to *FILE*.
+
+		  If **visual** is specified, control flow graph (CFG) will be
+		  built instead, and eBPF instructions will be presented with
+		  CFG in DOT format, on standard output.
 
 	**bpftool prog dump jited**  *PROG* [{ **file** *FILE* | **opcodes** }]
 		  Dump jited image (host machine code) of the program.

tools/bpf/bpftool/bash-completion/bpftool

@@ -147,7 +147,7 @@ _bpftool()
 
     # Deal with simplest keywords
     case $prev in
-        help|key|opcodes)
+        help|key|opcodes|visual)
             return 0
             ;;
         tag)
@@ -223,11 +223,16 @@ _bpftool()
                             return 0
                             ;;
                     *)
-                            _bpftool_once_attr 'file'
+                        _bpftool_once_attr 'file'
+                        if _bpftool_search_list 'xlated'; then
+                            COMPREPLY+=( $( compgen -W 'opcodes visual' -- \
+                                "$cur" ) )
+                        else
                             COMPREPLY+=( $( compgen -W 'opcodes' -- \
                                 "$cur" ) )
-                            return 0
-                            ;;
+                        fi
+                        return 0
+                        ;;
                     esac
                     ;;
                 pin)