perf srcline: Add configuration support for the addr2line style

perf srcline: Add configuration support for the addr2line style

Allow the addr2line style to be specified on the `perf report` command
line or in the .perfconfig file.

Committer testing:

The methods:

  # perf probe -x ~/bin/perf -F *__addr2line
  cmd__addr2line
  libbfd__addr2line
  libdw__addr2line
  llvm__addr2line
  #

So if we configure one of them, say 'addr2line':

  # perf config addr2line.style=addr2line
  # perf config addr2line.style
  addr2line.style=addr2line
  #

And have probes on all of them:

  # perf probe -x ~/bin/perf *__addr2line
  Added new events:
    probe_perf:cmd__addr2line (on *__addr2line in /home/acme/bin/perf)
    probe_perf:llvm__addr2line (on *__addr2line in /home/acme/bin/perf)
    probe_perf:libbfd__addr2line (on *__addr2line in /home/acme/bin/perf)
    probe_perf:libdw__addr2line (on *__addr2line in /home/acme/bin/perf)

  You can now use it in all perf tools, such as:

  	perf record -e probe_perf:libdw__addr2line -aR sleep 1

  #

Only the selected method should be used:

  # perf stat -e probe_perf:*_addr2line perf report -f --dso perf --stdio -s srcfile,srcline
  # Total Lost Samples: 0
  #
  # Samples: 4K of event 'cpu/cycles/Pu'
  # Event count (approx.): 5535180842
  #
  # Overhead  Source File   Source:Line
  # ........  ............  ...............
  #
      99.04%  inlineloop.c  inlineloop.c:21
       0.46%  inlineloop.c  inlineloop.c:20

  #
  # (Tip: For hierarchical output, try: perf report --hierarchy)
  #

   Performance counter stats for 'perf report -f --dso perf --stdio -s srcfile,srcline':

                  44      probe_perf:cmd__addr2line
                   0      probe_perf:llvm__addr2line
                   0      probe_perf:libbfd__addr2line
                   0      probe_perf:libdw__addr2line

         0.035915611 seconds time elapsed

         0.028008000 seconds user
         0.009051000 seconds sys
  #

I checked and that is the case for the other methods.

Also when using:

  # perf config addr2line.style=libdw,llvm

 Performance counter stats for 'perf report -f --dso perf --stdio -s srcfile,srcline':

                 0      probe_perf:cmd__addr2line
                23      probe_perf:llvm__addr2line
                 0      probe_perf:libbfd__addr2line
                44      probe_perf:libdw__addr2line

Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Tony Jones <tonyj@suse.de>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>