This patch let bpftool print .dot graph file into stdout.
This graph is generated by the following steps:
- iterate through the function list.
- generate basic-block(BB) definition for each BB in the function.
- draw out edges to connect BBs.
This patch is the initial support, the layout and decoration of the .dot
graph could be improved.
Also, it will be useful if we could visualize some performance data from
static analysis.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds out edges for each basic-block. We will need these out
edges to finish the .dot graph drawing.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch partition basic-block for each function in the CFG. The
algorithm is simple, we identify basic-block head in a first traversal,
then second traversal to identify the tail.
We could build extended basic-block (EBB) in next steps. EBB could make the
graph more readable when the eBPF sequence is big.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch detect all sub-programs from the eBPF sequence and keep the
information in the new CFG data structure.
The detection algorithm is basically the same as the one in verifier except
we need to use insn->off instead of insn->imm to get the pc-relative call
offset. Because verifier has modified insn->off/insn->imm during finishing
the verification.
Also, we don't need to do some sanity checks as verifier has done them.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
