[PATCH v2 10/10] perf parse-events: Disable a subset of bison warnings

[Ian Rogers]

Rather than disable all warnings with -w, disable specific warnings.
Predicate enabling the warnings on a recent version of bison.
Tested with GCC 9.3.0 and clang 9.0.1.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/util/Build | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 935ba132614c..c1692076469c 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -234,9 +234,17 @@ endif
 CFLAGS_parse-events-flex.o  += $(flex_flags)
 CFLAGS_pmu-flex.o           += $(flex_flags)
 CFLAGS_expr-flex.o          += $(flex_flags)
-CFLAGS_parse-events-bison.o += -DYYENABLE_NLS=0 -w
-CFLAGS_pmu-bison.o          += -DYYENABLE_NLS=0 -DYYLTYPE_IS_TRIVIAL=0 -w
-CFLAGS_expr-bison.o         += -DYYENABLE_NLS=0 -DYYLTYPE_IS_TRIVIAL=0 -w
+
+bison_flags := -DYYENABLE_NLS=0
+BISON_GE_353 := $(shell expr $(shell $(BISON) --version | grep bison | sed -e 's/.\+ \([0-9]\+\).\([0-9]\+\).\([0-9]\+\)/\1\2\3/g') \>\= 353)
+ifeq ($(BISON_GE_353),1)
+  bison_flags += -Wno-unused-parameter -Wno-nested-externs -Wno-error=implicit-function-declaration
+else
+  bison_flags += -w
+endif
+CFLAGS_parse-events-bison.o += $(bison_flags)
+CFLAGS_pmu-bison.o          += -DYYLTYPE_IS_TRIVIAL=0 $(bison_flags)
+CFLAGS_expr-bison.o         += -DYYLTYPE_IS_TRIVIAL=0 $(bison_flags)
 
 $(OUTPUT)util/parse-events.o: $(OUTPUT)util/parse-events-flex.c $(OUTPUT)util/parse-events-bison.c
 $(OUTPUT)util/pmu.o: $(OUTPUT)util/pmu-flex.c $(OUTPUT)util/pmu-bison.c
-- 
2.27.0.111.gc72c7da667-goog