On 03/01/2017 10:17 PM, Namhyung Kim wrote:
Hi Taeung,
On Wed, Mar 01, 2017 at 04:59:51AM +0900, Taeung Song wrote:
Currently perf-annotate show wrong line numbers.
For example,
Actual source code is as below
...
21 };
22
23 unsigned int limited_wgt;
24
25 unsigned int get_cond_maxprice(int wgt)
26 {
...
However, the output of perf-annotate is as below.
4 Disassembly of section .text:
6 0000000000400966 <get_cond_maxprice>:
7 get_cond_maxprice():
26 };
28 unsigned int limited_wgt;
30 unsigned int get_cond_maxprice(int wgt)
31 {
The cause is the wrong way counting line numbers
in symbol__parse_objdump_line().
So remove wrong current code counting line number and
use other method for it using functions related to addr2line
instead of the output of '-l' of objdump.
Hmm.. do you think it's a bug of objdump or it's perf failing to parse
the line number correctly? I'd like to see the output of `objdump -l`
Both are ok.
'objdump -l' hasn't a bug related to line number
and perf's method parsing the line number is ok.
But symbol__parse_objdump_line() wrongly count line numbers
after parsing it as below.
1172 /* /filename:linenr ? Save line number and ignore. */
1173 if (regexec(&file_lineno, line, 2, match, 0) == 0) {
1174 *line_nr = atoi(line + match[1].rm_so);
1175 return 0;
1176 }
...
1208 dl = disasm_line__new(offset, parsed_line, privsize,
*line_nr, arch, map);
1209 free(line);
1210 (*line_nr)++;
Increasing line_nr each asm line is wrong method.
Because 'line_nr' means actual source code line number.
Sure, I can fix only the wrong counting way.
But the above parsing method(1172~1176) is never used because of 'grep -v'
in command as below.
(the grep already remove lines containing filename:linenr of output)
1435 snprintf(command, sizeof(command),
1436 "%s %s%s --start-address=0x%016" PRIx64
1437 " --stop-address=0x%016" PRIx64
1438 " -l -d %s %s -C %s 2>/dev/null|grep -v %s|expand",
1439 objdump_path ? objdump_path : "objdump",
1440 disassembler_style ? "-M " : "",
1441 disassembler_style ? disassembler_style : "",
1442 map__rip_2objdump(map, sym->start),
1443 map__rip_2objdump(map, sym->end),
1444 symbol_conf.annotate_asm_raw ? "" : "--no-show-raw",
1445 symbol_conf.annotate_src ? "-S" : "",
1446 symfs_filename, symfs_filename);
Therefore, I think it is better to do three things
1) fix the wrong counting line number problem
2) remove unused the line number parsing method
3) In addtion, a bit reduce objdump dependency
using functions related to addr2line of perf.
What do you think about that ?
Is it bad idea ?
However, despite the correct line numbers,
we can't show proper source code view
because of limitations from output of 'objdump -S'.
So, next commit will resolve the limitations from 'objdump -S'
with the new source code view.
It seems not related with this commit..
Okey, will remove the mention.
Thanks,
Taeung
