perf symbols: Cache /proc/kallsyms files by build-id

So that when we don't have a vmlinux handy we can store the
kallsyms for later use by 'perf report'.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1263501006-14185-3-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 594156e..36b7c71 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -144,8 +144,9 @@
 int sysfs__read_build_id(const char *filename, void *bf, size_t size);
 bool dsos__read_build_ids(void);
 int build_id__sprintf(u8 *self, int len, char *bf);
-int kallsyms__parse(void *arg, int (*process_symbol)(void *arg, const char *name,
-						     char type, u64 start));
+int kallsyms__parse(const char *filename, void *arg,
+		    int (*process_symbol)(void *arg, const char *name,
+					  char type, u64 start));
 
 int symbol__init(void);
 bool symbol_type__is_a(char symbol_type, enum map_type map_type);