perf tools: Use __maybe_used for unused variables

perf defines both __used and __unused variables to use for marking
unused variables. The variable __used is defined to
__attribute__((__unused__)), which contradicts the kernel definition to
__attribute__((__used__)) for new gcc versions. On Android, __used is
also defined in system headers and this leads to warnings like: warning:
'__used__' attribute ignored

__unused is not defined in the kernel and is not a standard definition.
If __unused is included everywhere instead of __used, this leads to
conflicts with glibc headers, since glibc has a variables with this name
in its headers.

The best approach is to use __maybe_unused, the definition used in the
kernel for __attribute__((unused)). In this way there is only one
definition in perf sources (instead of 2 definitions that point to the
same thing: __used and __unused) and it works on both Linux and Android.
This patch simply replaces all instances of __used and __unused with
__maybe_unused.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1347315303-29906-7-git-send-email-irina.tirdea@intel.com
[ committer note: fixed up conflict with a116e05 in builtin-sched.c ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 02f49eb..dab347d 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -417,7 +417,7 @@
 	return 0;
 }
 
-static int run_perf_stat(int argc __used, const char **argv)
+static int run_perf_stat(int argc __maybe_unused, const char **argv)
 {
 	unsigned long long t0, t1;
 	struct perf_evsel *counter, *first;
@@ -634,7 +634,9 @@
 	return color;
 }
 
-static void print_stalled_cycles_frontend(int cpu, struct perf_evsel *evsel __used, double avg)
+static void print_stalled_cycles_frontend(int cpu,
+					  struct perf_evsel *evsel
+					  __maybe_unused, double avg)
 {
 	double total, ratio = 0.0;
 	const char *color;
@@ -651,7 +653,9 @@
 	fprintf(output, " frontend cycles idle   ");
 }
 
-static void print_stalled_cycles_backend(int cpu, struct perf_evsel *evsel __used, double avg)
+static void print_stalled_cycles_backend(int cpu,
+					 struct perf_evsel *evsel
+					 __maybe_unused, double avg)
 {
 	double total, ratio = 0.0;
 	const char *color;
@@ -668,7 +672,9 @@
 	fprintf(output, " backend  cycles idle   ");
 }
 
-static void print_branch_misses(int cpu, struct perf_evsel *evsel __used, double avg)
+static void print_branch_misses(int cpu,
+				struct perf_evsel *evsel __maybe_unused,
+				double avg)
 {
 	double total, ratio = 0.0;
 	const char *color;
@@ -685,7 +691,9 @@
 	fprintf(output, " of all branches        ");
 }
 
-static void print_l1_dcache_misses(int cpu, struct perf_evsel *evsel __used, double avg)
+static void print_l1_dcache_misses(int cpu,
+				   struct perf_evsel *evsel __maybe_unused,
+				   double avg)
 {
 	double total, ratio = 0.0;
 	const char *color;
@@ -702,7 +710,9 @@
 	fprintf(output, " of all L1-dcache hits  ");
 }
 
-static void print_l1_icache_misses(int cpu, struct perf_evsel *evsel __used, double avg)
+static void print_l1_icache_misses(int cpu,
+				   struct perf_evsel *evsel __maybe_unused,
+				   double avg)
 {
 	double total, ratio = 0.0;
 	const char *color;
@@ -719,7 +729,9 @@
 	fprintf(output, " of all L1-icache hits  ");
 }
 
-static void print_dtlb_cache_misses(int cpu, struct perf_evsel *evsel __used, double avg)
+static void print_dtlb_cache_misses(int cpu,
+				    struct perf_evsel *evsel __maybe_unused,
+				    double avg)
 {
 	double total, ratio = 0.0;
 	const char *color;
@@ -736,7 +748,9 @@
 	fprintf(output, " of all dTLB cache hits ");
 }
 
-static void print_itlb_cache_misses(int cpu, struct perf_evsel *evsel __used, double avg)
+static void print_itlb_cache_misses(int cpu,
+				    struct perf_evsel *evsel __maybe_unused,
+				    double avg)
 {
 	double total, ratio = 0.0;
 	const char *color;
@@ -753,7 +767,9 @@
 	fprintf(output, " of all iTLB cache hits ");
 }
 
-static void print_ll_cache_misses(int cpu, struct perf_evsel *evsel __used, double avg)
+static void print_ll_cache_misses(int cpu,
+				  struct perf_evsel *evsel __maybe_unused,
+				  double avg)
 {
 	double total, ratio = 0.0;
 	const char *color;
@@ -1059,8 +1075,8 @@
 	NULL
 };
 
-static int stat__set_big_num(const struct option *opt __used,
-			     const char *s __used, int unset)
+static int stat__set_big_num(const struct option *opt __maybe_unused,
+			     const char *s __maybe_unused, int unset)
 {
 	big_num_opt = unset ? 0 : 1;
 	return 0;
@@ -1154,7 +1170,7 @@
 	return perf_evlist__add_default_attrs(evsel_list, very_very_detailed_attrs);
 }
 
-int cmd_stat(int argc, const char **argv, const char *prefix __used)
+int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
 {
 	struct perf_evsel *pos;
 	int status = -ENOMEM;