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, 7 insertions, 5 deletions

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index f4190b5764de..2c54cdd8ae1b 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -1824,7 +1824,7 @@ process_op(struct event_format *event, struct print_arg *arg, char **tok)
 }
 
 static enum event_type
-process_entry(struct event_format *event __unused, struct print_arg *arg,
+process_entry(struct event_format *event __maybe_unused, struct print_arg *arg,
               char **tok)
 {
         enum event_type type;
@@ -2458,7 +2458,8 @@ process_paren(struct event_format *event, struct print_arg *arg, char **tok)
 
 
 static enum event_type
-process_str(struct event_format *event __unused, struct print_arg *arg, char **tok)
+process_str(struct event_format *event __maybe_unused, struct print_arg *arg,
+            char **tok)
 {
         enum event_type type;
         char *token;
@@ -3653,7 +3654,8 @@ static void free_args(struct print_arg *args)
 }
 
 static char *
-get_bprint_format(void *data, int size __unused, struct event_format *event)
+get_bprint_format(void *data, int size __maybe_unused,
+                  struct event_format *event)
 {
         struct pevent *pevent = event->pevent;
         unsigned long long addr;
diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h
index 3318963f1c98..a4bbe2437925 100644
--- a/tools/lib/traceevent/event-parse.h
+++ b/tools/lib/traceevent/event-parse.h
@@ -24,8 +24,8 @@
 #include <stdarg.h>
 #include <regex.h>
 
-#ifndef __unused
-#define __unused __attribute__ ((unused))
+#ifndef __maybe_unused
+#define __maybe_unused __attribute__((unused))
 #endif
 
 /* ----------------------- trace_seq ----------------------- */