[RFC PATCH] perf: parse-events: Fix compilation error while defining DEBUG_PARSER

[Clément Le Goffic]

Compiling perf tool with 'DEBUG_PARSER=1' leads to errors:

$> make -C tools/perf PARSER_DEBUG=1 NO_LIBTRACEEVENT=1
...
  CC      util/expr-flex.o
  CC      util/expr.o
util/parse-events.c:33:12: error: redundant redeclaration of ‘parse_events_debug’ [-Werror=redundant-decls]
   33 | extern int parse_events_debug;
      |            ^~~~~~~~~~~~~~~~~~
In file included from util/parse-events.c:18:
util/parse-events-bison.h:43:12: note: previous declaration of ‘parse_events_debug’ with type ‘int’
   43 | extern int parse_events_debug;
      |            ^~~~~~~~~~~~~~~~~~
util/expr.c:27:12: error: redundant redeclaration of ‘expr_debug’ [-Werror=redundant-decls]
   27 | extern int expr_debug;
      |            ^~~~~~~~~~
In file included from util/expr.c:11:
util/expr-bison.h:43:12: note: previous declaration of ‘expr_debug’ with type ‘int’
   43 | extern int expr_debug;
      |            ^~~~~~~~~~
cc-1: all warnings being treated as errors

Remove extern declaration from the parse-envents.c file as there is a
conflict with the ones generated using bison and yacc tools from the file
parse-events.[ly].

Signed-off-by: Clément Le Goffic <clement.legoffic@xxxxxxxxxxx>
---
I don't know how bison and yacc work together.
To me if those symbols are already generated (I don't know how), we
should get rid of them in the source file `parse-events.c`.
For my knowledge, if someone has the explanation of how they are
generated, I am interested as I didn't find any link to some part of
parse-events.[yl] files.

To: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
To: Ingo Molnar <mingo@xxxxxxxxxx>
To: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
To: Namhyung Kim <namhyung@xxxxxxxxxx>
To: Mark Rutland <mark.rutland@xxxxxxx>
To: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
To: Jiri Olsa <jolsa@xxxxxxxxxx>
To: Ian Rogers <irogers@xxxxxxxxxx>
To: Adrian Hunter <adrian.hunter@xxxxxxxxx>
To: "Liang, Kan" <kan.liang@xxxxxxxxxxxxxxx>
To: John Garry <john.g.garry@xxxxxxxxxx>
To: James Clark <james.clark@xxxxxxx>
Cc: linux-perf-users@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 tools/perf/util/expr.c         | 4 ----
 tools/perf/util/parse-events.c | 3 ---
 2 files changed, 7 deletions(-)

diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c
index b8875aac8f87..b2536a59c44e 100644
--- a/tools/perf/util/expr.c
+++ b/tools/perf/util/expr.c
@@ -25,10 +25,6 @@
 #include <math.h>
 #include "pmu.h"

-#ifdef PARSER_DEBUG
-extern int expr_debug;
-#endif
-
 struct expr_id_data {
 	union {
 		struct {
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 6ed0f9c5581d..8d5fb05f20c2 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -31,9 +31,6 @@

 #define MAX_NAME_LEN 100

-#ifdef PARSER_DEBUG
-extern int parse_events_debug;
-#endif
 static int get_config_terms(const struct parse_events_terms *head_config,
 			    struct list_head *head_terms);
 static int parse_events_terms__copy(const struct parse_events_terms *src,

base-commit: c3f38fa61af77b49866b006939479069cd451173
--
2.34.1