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, 3 insertions, 3 deletions

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 04eafd3939df..f0a910371377 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -313,8 +313,8 @@ static struct ins_ops dec_ops = {
 	.scnprintf = dec__scnprintf,
 };
 
-static int nop__scnprintf(struct ins *ins __used, char *bf, size_t size,
-			  struct ins_operands *ops __used)
+static int nop__scnprintf(struct ins *ins __maybe_unused, char *bf, size_t size,
+			  struct ins_operands *ops __maybe_unused)
 {
 	return scnprintf(bf, size, "%-6.6s", "nop");
 }
@@ -416,7 +416,7 @@ static struct ins *ins__find(const char *name)
 	return bsearch(name, instructions, nmemb, sizeof(struct ins), ins__cmp);
 }
 
-int symbol__annotate_init(struct map *map __used, struct symbol *sym)
+int symbol__annotate_init(struct map *map __maybe_unused, struct symbol *sym)
 {
 	struct annotation *notes = symbol__annotation(sym);
 	pthread_mutex_init(&notes->lock, NULL);