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 <[email protected]>
Acked-by: Pekka Enberg <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
[ committer note: fixed up conflict with a116e05 in builtin-sched.c ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

1 files changed, 9 insertions, 5 deletions

diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index 7a2fbd8855b7..0981bc7a2917 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -170,7 +170,7 @@ static int hist_entry__dso_snprintf(struct hist_entry *self, char *bf,
 
 static int _hist_entry__sym_snprintf(struct map *map, struct symbol *sym,
 				     u64 ip, char level, char *bf, size_t size,
-				     unsigned int width __used)
+				     unsigned int width __maybe_unused)
 {
 	size_t ret = 0;
 
@@ -205,7 +205,8 @@ struct sort_entry sort_dso = {
 };
 
 static int hist_entry__sym_snprintf(struct hist_entry *self, char *bf,
-				    size_t size, unsigned int width __used)
+				    size_t size,
+				    unsigned int width __maybe_unused)
 {
 	return _hist_entry__sym_snprintf(self->ms.map, self->ms.sym, self->ip,
 					 self->level, bf, size, width);
@@ -248,7 +249,8 @@ sort__srcline_cmp(struct hist_entry *left, struct hist_entry *right)
 }
 
 static int hist_entry__srcline_snprintf(struct hist_entry *self, char *bf,
-				   size_t size, unsigned int width __used)
+					size_t size,
+					unsigned int width __maybe_unused)
 {
 	FILE *fp;
 	char cmd[PATH_MAX + 2], *path = self->srcline, *nl;
@@ -397,7 +399,8 @@ sort__sym_to_cmp(struct hist_entry *left, struct hist_entry *right)
 }
 
 static int hist_entry__sym_from_snprintf(struct hist_entry *self, char *bf,
-				    size_t size, unsigned int width __used)
+					size_t size,
+					unsigned int width __maybe_unused)
 {
 	struct addr_map_symbol *from = &self->branch_info->from;
 	return _hist_entry__sym_snprintf(from->map, from->sym, from->addr,
@@ -406,7 +409,8 @@ static int hist_entry__sym_from_snprintf(struct hist_entry *self, char *bf,
 }
 
 static int hist_entry__sym_to_snprintf(struct hist_entry *self, char *bf,
-				    size_t size, unsigned int width __used)
+				       size_t size,
+				       unsigned int width __maybe_unused)
 {
 	struct addr_map_symbol *to = &self->branch_info->to;
 	return _hist_entry__sym_snprintf(to->map, to->sym, to->addr,