bpftool: Print subprog address properly

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[+17]
    30: (18) r2 = subprog[+25]
  ...
  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[-47]

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210226204931.3885458-1-yhs@fb.com

diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c
index 8608cd68cdd0794ba711925e0ca71e6bf98f33ff..6fc3e6f7f40cde593c2c1e0dfa5a2efc52f8bb5d 100644 (file)
--- 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);
        else
                snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
                         "0x%llx", (unsigned long long)full_imm);