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objtool: Provide stats for jump_labels

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Add objtool --stats to count the jump_label sites it encounters.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210506194158.153101906@infradead.org
This commit is contained in:
Peter Zijlstra 2021-05-06 21:34:04 +02:00 committed by Ingo Molnar
parent 6d37b83c5d
commit e2d9494bef
2 changed files with 23 additions and 2 deletions
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22
tools/objtool/check.c
View file

@ -1225,8 +1225,15 @@ static int handle_jump_alt(struct objtool_file *file,
struct instruction *orig_insn,
struct instruction **new_insn)
{
if (orig_insn->type == INSN_NOP)
if (orig_insn->type == INSN_NOP) {
do_nop:
if (orig_insn->len == 2)
file->jl_nop_short++;
else
file->jl_nop_long++;
return 0;
}
if (orig_insn->type != INSN_JUMP_UNCONDITIONAL) {
WARN_FUNC("unsupported instruction at jump label",
@ -1245,9 +1252,14 @@ static int handle_jump_alt(struct objtool_file *file,
orig_insn->offset, orig_insn->len,
arch_nop_insn(orig_insn->len));
orig_insn->type = INSN_NOP;
return 0;
goto do_nop;
}
if (orig_insn->len == 2)
file->jl_short++;
else
file->jl_long++;
*new_insn = list_next_entry(orig_insn, list);
return 0;
}
@ -1328,6 +1340,12 @@ static int add_special_section_alts(struct objtool_file *file)
free(special_alt);
}
if (stats) {
printf("jl\\\tNOP\tJMP\n");
printf("short:\t%ld\t%ld\n", file->jl_nop_short, file->jl_short);
printf("long:\t%ld\t%ld\n", file->jl_nop_long, file->jl_long);
}
out:
return ret;
}

3
tools/objtool/include/objtool/objtool.h
View file

@ -22,6 +22,9 @@ struct objtool_file {
struct list_head static_call_list;
struct list_head mcount_loc_list;
bool ignore_unreachables, c_file, hints, rodata;
unsigned long jl_short, jl_long;
unsigned long jl_nop_short, jl_nop_long;
};
struct objtool_file *objtool_open_read(const char *_objname);