perf test: Parse events workaround for dash/minus

Skip an event configuration for event names with a dash/minus in them.
Events with a dash/minus in their name cause parsing issues as legacy
encoding of events would use a dash/minus as a separator.

The parser separates events with dashes into prefixes and suffixes and
then recombines them. Unfortunately if an event has part of its name
that matches a legacy token then the recombining fails.

This is seen for branch-brs where branch is a legacy token. branch-brs
was introduced to sysfs in:

  https://lore.kernel.org/all/[email protected]/

The failure is shown below as well as the workaround to use a config
where the dash/minus isn't treated specially:

```
  $ perf stat -e branch-brs true
  event syntax error: 'branch-brs'
                             \___ parser error

  $ perf stat -e cpu/branch-brs/ true

   Performance counter stats for 'true':

              46,179      cpu/branch-brs/
```

Signed-off-by: Ian Rogers <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Garry <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

tools/perf/tests/parse-events.c

@@ -2237,6 +2237,19 @@ static int test__pmu_events(struct test_suite *test __maybe_unused, int subtest
 			pr_debug("Test PMU event failed for '%s'", name);
 			ret = combine_test_results(ret, test_ret);
 		}
+		/*
+		 * Names containing '-' are recognized as prefixes and suffixes
+		 * due to '-' being a legacy PMU separator. This fails when the
+		 * prefix or suffix collides with an existing legacy token. For
+		 * example, branch-brs has a prefix (branch) that collides with
+		 * a PE_NAME_CACHE_TYPE token causing a parse error as a suffix
+		 * isn't expected after this. As event names in the config
+		 * slashes are allowed a '-' in the name we check this works
+		 * above.
+		 */
+		if (strchr(ent->d_name, '-'))
+			continue;
+
 		snprintf(name, sizeof(name), "%s:u,cpu/event=%s/u", ent->d_name, ent->d_name);
 		e.name  = name;
 		e.check = test__checkevent_pmu_events_mix;