perf tools: Record whether a dso has data

Add 'data.status' to record whether a dso has data (i.e. an object
file).  This is used to avoid repeatedly creating the file name and
attempting to open a file that is not present.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
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/r/1406035081-14301-10-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index c239e86..aeb7bcb 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -40,6 +40,12 @@
 	DSO_SWAP__YES,
 };
 
+enum dso_data_status {
+	DSO_DATA_STATUS_ERROR	= -1,
+	DSO_DATA_STATUS_UNKNOWN	= 0,
+	DSO_DATA_STATUS_OK	= 1,
+};
+
 #define DSO__SWAP(dso, type, val)			\
 ({							\
 	type ____r = val;				\
@@ -104,6 +110,7 @@
 	struct {
 		struct rb_root	 cache;
 		int		 fd;
+		int		 status;
 		size_t		 file_size;
 		struct list_head open_entry;
 	} data;