perf tools: Allow handling a NULL cpu_map as meaning "all cpus"

Or one with cpu_map->map[0] == -1.

Reducing the boilerplate in setting up an evlist by nor requiring a
cpu_map to be created at all.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-rnaqn3dtnsfo1wlbbf3fhx00@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/cpumap.h b/tools/perf/util/cpumap.h
index 17b5264..2f68a3b 100644
--- a/tools/perf/util/cpumap.h
+++ b/tools/perf/util/cpumap.h
@@ -2,6 +2,7 @@
 #define __PERF_CPUMAP_H
 
 #include <stdio.h>
+#include <stdbool.h>
 
 struct cpu_map {
 	int nr;
@@ -14,4 +15,14 @@
 struct cpu_map *cpu_map__read(FILE *file);
 size_t cpu_map__fprintf(struct cpu_map *map, FILE *fp);
 
+static inline int cpu_map__nr(const struct cpu_map *map)
+{
+	return map ? map->nr : 1;
+}
+
+static inline bool cpu_map__all(const struct cpu_map *map)
+{
+	return map ? map->map[0] == -1 : true;
+}
+
 #endif /* __PERF_CPUMAP_H */