perf tools: Add a global variable "const char *input_name"

Currently many perf commands annotate/evlist/report/script/lock etc all
support "-i" option to chose a specific perf data, and all of them
create a local "input_name" to save the file name for that perf data.

Since most of these commands need it, we can add a global variable for
it, also it can some other benefits:

1. When calling script browser inside hists/annotation browser, it needs
to know the perf data file name to run that script.

2. For further feature like runtime switching to another perf data file,
this variable can also help.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1351569369-26732-2-git-send-email-feng.tang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-evlist.c b/tools/perf/builtin-evlist.c
index 997afb8..c20f1dc 100644
--- a/tools/perf/builtin-evlist.c
+++ b/tools/perf/builtin-evlist.c
@@ -48,12 +48,12 @@
 
 #define if_print(field) __if_print(&first, #field, pos->attr.field)
 
-static int __cmd_evlist(const char *input_name, struct perf_attr_details *details)
+static int __cmd_evlist(const char *file_name, struct perf_attr_details *details)
 {
 	struct perf_session *session;
 	struct perf_evsel *pos;
 
-	session = perf_session__new(input_name, O_RDONLY, 0, false, NULL);
+	session = perf_session__new(file_name, O_RDONLY, 0, false, NULL);
 	if (session == NULL)
 		return -ENOMEM;
 
@@ -111,7 +111,6 @@
 int cmd_evlist(int argc, const char **argv, const char *prefix __maybe_unused)
 {
 	struct perf_attr_details details = { .verbose = false, };
-	const char *input_name = NULL;
 	const struct option options[] = {
 	OPT_STRING('i', "input", &input_name, "file", "Input file name"),
 	OPT_BOOLEAN('F', "freq", &details.freq, "Show the sample frequency"),