perf symbols: Filter out hidden symbols from labels
authorJiri Olsa <jolsa@redhat.com>
Mon, 28 Jan 2019 13:35:26 +0000 (14:35 +0100)
committerArnaldo Carvalho de Melo <acme@redhat.com>
Mon, 4 Feb 2019 18:50:38 +0000 (15:50 -0300)
commit59a17706915fe5ea6f711e1f92d4fb706bce07fe
tree7e95b9d80d17445b3f4df80b35f68dd4f905bc67
parent843cf70ed29a7fb51f1e796c1d6e1ba3620250ac
perf symbols: Filter out hidden symbols from labels

When perf is built with the annobin plugin (RHEL8 build) extra symbols
are added to its binary:

  # nm perf | grep annobin | head -10
  0000000000241100 t .annobin_annotate.c
  0000000000326490 t .annobin_annotate.c
  0000000000249255 t .annobin_annotate.c_end
  00000000003283a8 t .annobin_annotate.c_end
  00000000001bce18 t .annobin_annotate.c_end.hot
  00000000001bce18 t .annobin_annotate.c_end.hot
  00000000001bc3e2 t .annobin_annotate.c_end.unlikely
  00000000001bc400 t .annobin_annotate.c_end.unlikely
  00000000001bce18 t .annobin_annotate.c.hot
  00000000001bce18 t .annobin_annotate.c.hot
  ...

Those symbols have no use for report or annotation and should be
skipped.  Moreover they interfere with the DWARF unwind test on the PPC
arch, where they are mixed with checked symbols and then the test fails:

  # perf test dwarf -v
  59: Test dwarf unwind                                     :
  --- start ---
  test child forked, pid 8515
  unwind: .annobin_dwarf_unwind.c:ip = 0x10dba40dc (0x2740dc)
  ...
  got: .annobin_dwarf_unwind.c 0x10dba40dc, expecting test__arch_unwind_sample
  unwind: failed with 'no error'

The annobin symbols are defined as NOTYPE/LOCAL/HIDDEN:

  # readelf -s ./perf | grep annobin | head -1
    40: 00000000001bce4f     0 NOTYPE  LOCAL  HIDDEN    13 .annobin_init.c

They can still pass the check for the label symbol. Adding check for
HIDDEN and INTERNAL (as suggested by Nick below) visibility and filter
out such symbols.

>   Just to be awkward, if you are going to ignore STV_HIDDEN
>   symbols then you should probably also ignore STV_INTERNAL ones
>   as well...  Annobin does not generate them, but you never know,
>   one day some other tool might create some.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nick Clifton <nickc@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190128133526.GD15461@krava
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
tools/perf/util/symbol-elf.c