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>

2 files changed, 10 insertions, 8 deletions

diff --git a/tools/perf/util/scripting-engines/trace-event-perl.c b/tools/perf/util/scripting-engines/trace-event-perl.c
index 94e6736..ffde3e4 100644
--- a/tools/perf/util/scripting-engines/trace-event-perl.c
+++ b/tools/perf/util/scripting-engines/trace-event-perl.c
@@ -257,10 +257,10 @@ static inline struct event_format *find_cache_event(struct perf_evsel *evsel)
 	return event;
 }
 
-static void perl_process_tracepoint(union perf_event *perf_event __unused,
+static void perl_process_tracepoint(union perf_event *perf_event __maybe_unused,
 				    struct perf_sample *sample,
 				    struct perf_evsel *evsel,
-				    struct machine *machine __unused,
+				    struct machine *machine __maybe_unused,
 				    struct addr_location *al)
 {
 	struct format_field *field;
@@ -349,8 +349,8 @@ static void perl_process_tracepoint(union perf_event *perf_event __unused,
 static void perl_process_event_generic(union perf_event *event,
 				       struct perf_sample *sample,
 				       struct perf_evsel *evsel,
-				       struct machine *machine __unused,
-				       struct addr_location *al __unused)
+				       struct machine *machine __maybe_unused,
+				       struct addr_location *al __maybe_unused)
 {
 	dSP;
 
diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index afba097..730c663 100644
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -221,10 +221,11 @@ static inline struct event_format *find_cache_event(struct perf_evsel *evsel)
 	return event;
 }
 
-static void python_process_tracepoint(union perf_event *perf_event __unused,
+static void python_process_tracepoint(union perf_event *perf_event
+				      __maybe_unused,
 				 struct perf_sample *sample,
 				 struct perf_evsel *evsel,
-				 struct machine *machine __unused,
+				 struct machine *machine __maybe_unused,
 				 struct addr_location *al)
 {
 	PyObject *handler, *retval, *context, *t, *obj, *dict = NULL;
@@ -339,10 +340,11 @@ static void python_process_tracepoint(union perf_event *perf_event __unused,
 	Py_DECREF(t);
 }
 
-static void python_process_general_event(union perf_event *perf_event __unused,
+static void python_process_general_event(union perf_event *perf_event
+					 __maybe_unused,
 					 struct perf_sample *sample,
 					 struct perf_evsel *evsel,
-					 struct machine *machine __unused,
+					 struct machine *machine __maybe_unused,
 					 struct addr_location *al)
 {
 	PyObject *handler, *retval, *t, *dict;