Allow for a synthesized branch stack to be added to samples. As with
synthesized call chains, the sample type cannot be changed because it is
needed to continue to parse events. So add and use helper function
evsel__has_br_stack() to indicate a branch stack, whether original or
synthesized.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20200429150751.12570-6-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>