This patch helps with Sukadev's vendor event tree where such events can happen.

>From Andi Kleen:
 Any event including a .c/.o/.bpf currently triggers BPF compilation or loading
 and then an error. This can happen for some Intel vendor events, which cannot
 be used.

This patch fixes this problem by forbidding BPF file patch containing '{', '}'
and ',', make sure flex consumes the leading '{', instead of matching it using
a BPF file path.

Tested result:

  $ perf stat -e '{unc_p_clockticks,unc_p_power_state_occupancy.cores_c0}' -a -I 1000
  invalid or unsupported event: '{unc_p_clockticks,unc_p_power_state_occupancy.cores_c0}'
  Run 'perf list' for a list of valid events
  (as expected, interperted as event)

  $ perf stat -e 'aaa.c' -a -I 1000
  ERROR: problems with path aaa.c: No such file or directory
  (as expected, interpreted as BPF source)

  $ perf stat -e 'aaa.ccc' -a -I 1000
  invalid or unsupported event: 'aaa.ccc'
  (as expected, interpreted as event)

  $ perf stat -e '{aaa.c}' -a -I 1000
  ERROR: problems with path aaa.c: No such file or directory
  event syntax error: '{aaa.c}'
  <SKIP>
  (as expected, interpreted as BPF source)

  $ perf stat -e '{cycles,aaa.c}' -a -I 1000
  ERROR: problems with path aaa.c: No such file or directory
  event syntax error: '{cycles,aaa.c}'
  (as expected, interpreted as BPF source)
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Reported-by: NAndi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1475900185-37967-1-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>