On 2/8/21 10:22 AM, Andrii Nakryiko wrote:

On Thu, Feb 4, 2021 at 5:53 PM Yonghong Song [off-list ref] wrote:

quoted

With later hashmap example, using bpftool xlated output may
look like:
   int dump_task(struct bpf_iter__task * ctx):
   ; struct task_struct *task = ctx->task;
      0: (79) r2 = *(u64 *)(r1 +8)
   ; if (task == (void *)0 || called > 0)
   ...
     19: (18) r2 = subprog[+18]
     30: (18) r2 = subprog[+26]
   ...
   36: (95) exit
   __u64 check_hash_elem(struct bpf_map * map, __u32 * key, __u64 * val,
                         struct callback_ctx * data):
   ; struct bpf_iter__task *ctx = data->ctx;
     37: (79) r5 = *(u64 *)(r4 +0)
   ...
     55: (95) exit
   __u64 check_percpu_elem(struct bpf_map * map, __u32 * key,
                           __u64 * val, void * unused):
   ; check_percpu_elem(struct bpf_map *map, __u32 *key, __u64 *val, void *unused)
     56: (bf) r6 = r3
   ...
     83: (18) r2 = subprog[+-46]

this +-46 looks very confusing...

Make sense, will use %+d to have either +46 or -46.

quoted

Signed-off-by: Yonghong Song <redacted>
---
  tools/bpf/bpftool/xlated_dumper.c | 3 +++
  1 file changed, 3 insertions(+)

diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c
index 8608cd68cdd0..7bdd90503727 100644
--- a/tools/bpf/bpftool/xlated_dumper.c
+++ b/tools/bpf/bpftool/xlated_dumper.c

@@ -196,6 +196,9 @@ static const char *print_imm(void *private_data,
         else if (insn->src_reg == BPF_PSEUDO_MAP_VALUE)
                 snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
                          "map[id:%u][0]+%u", insn->imm, (insn + 1)->imm);
+       else if (insn->src_reg == BPF_PSEUDO_FUNC)
+               snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
+                        "subprog[+%d]", insn->imm + 1);

why not `subprog[%+d]` instead (see above about confusing output)

quoted

         else
                 snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
                          "0x%llx", (unsigned long long)full_imm);
--
2.24.1