perf tools: Add skip check in tool_pmu__event_to_str()

Some topdown related metrics may fail on hybrid machines.

$ perf stat -M tma_frontend_bound
Cannot resolve IDs for tma_frontend_bound:
cpu_atom@TOPDOWN_FE_BOUND.ALL@ / (8 * cpu_atom@CPU_CLK_UNHALTED.CORE@)

In the find_tool_events(), the tool_pmu__event_to_str() is used to
compare the tool_events. It only checks the event name, no PMU or arch.
So the tool_events[TOOL_PMU__EVENT_SLOTS] is set to true, because the
p-core Topdown metrics has "slots" event.
The tool_events is shared. So when parsing the e-core metrics, the
"slots" is automatically added.

The "slots" event as a tool event should only be available on arm64. It
has a different meaning on X86. The tool_pmu__skip_event() intends
handle the case. Apply it for tool_pmu__event_to_str() as well.

There is a lack of sanity check in the expr__get_id(). Add the check.

Closes: https://lore.kernel.org/lkml/[e-mail]/
Fixes: 069057239a67 ("perf tool_pmu: Move expr literals to tool_pmu")
Signed-off-by: Kan Liang <[e-mail]>
Reviewed-by: Ian Rogers <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Namhyung Kim <[e-mail]>

tools/perf/util/expr.c

···
 int expr__get_id(struct expr_parse_ctx *ctx, const char *id,
 		 struct expr_id_data **data)
 {
+	if (!ctx || !id)
+		return -1;
 	return hashmap__find(ctx->ids, id, data) ? 0 : -1;
 }
 

tools/perf/util/tool_pmu.c

···
 
 const char *tool_pmu__event_to_str(enum tool_pmu_event ev)
 {
-	if (ev > TOOL_PMU__EVENT_NONE && ev < TOOL_PMU__EVENT_MAX)
+	if ((ev > TOOL_PMU__EVENT_NONE && ev < TOOL_PMU__EVENT_MAX) &&
+	    !tool_pmu__skip_event(tool_pmu__event_names[ev]))
 		return tool_pmu__event_names[ev];
 
 	return NULL;