Re: [PATCH 2/2] perf parse-events: enable more flex/yacc warnings

From: Arnaldo Carvalho de Melo
Date: Wed Jun 10 2020 - 10:05:32 EST

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Em Tue, Jun 09, 2020 at 04:43:44PM -0700, Ian Rogers escreveu:
> All C compiler warnings are disabled are disabled by -w. This change
> removes the -w from flex and bison targets. To avoid implicit
> declarations header files are declared as targets and included.
>
> Tested with GCC 9.3.0 and clang 9.0.1.
>
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> ---
> tools/perf/util/Build | 55 ++++++++++++++++++++++------------
> tools/perf/util/expr.y | 2 ++
> tools/perf/util/parse-events.y | 1 +
> 3 files changed, 39 insertions(+), 19 deletions(-)
>
> diff --git a/tools/perf/util/Build b/tools/perf/util/Build
> index 8d18380ecd10..8d47dd3ecf2e 100644
> --- a/tools/perf/util/Build
> +++ b/tools/perf/util/Build
> @@ -191,36 +191,53 @@ CFLAGS_llvm-utils.o += -DPERF_INCLUDE_DIR="BUILD_STR($(perf_include_dir_SQ))"
> # avoid compiler warnings in 32-bit mode
> CFLAGS_genelf_debug.o += -Wno-packed
>
> -$(OUTPUT)util/parse-events-flex.c: util/parse-events.l $(OUTPUT)util/parse-events-bison.c
> +$(OUTPUT)util/parse-events-flex.c $(OUTPUT)util/parse-events-flex.h: util/parse-events.l $(OUTPUT)util/parse-events-bison.c
> $(call rule_mkdir)
> - $(Q)$(call echo-cmd,flex)$(FLEX) -o $@ --header-file=$(OUTPUT)util/parse-events-flex.h $(PARSER_DEBUG_FLEX) util/parse-events.l
> + $(Q)$(call echo-cmd,flex)$(FLEX) -o $(OUTPUT)util/parse-events-flex.c \
> + --header-file=$(OUTPUT)util/parse-events-flex.h \
> + $(PARSER_DEBUG_FLEX) $<

Wouldn't this be equivalent to:

+ $(Q)$(call echo-cmd,flex)$(FLEX) -o $(OUTPUT)util/parse-events-flex.c --header-file=$(OUTPUT)util/parse-events-flex.h $(PARSER_DEBUG_FLEX) $< \
+ --header-file=$(OUTPUT)util/parse-events-flex.h

So that we match what is being replaced more easily?

You have to replace $@ by (OUTPUT)util/parse-events-flex.c because now
you're multi-target, but then as $@ is replaced by whichever of those
targets caused the recipe to run, and what is in other places is
$(OUTPUT)util/parse-events-flex.c, we can continue to use $@, no?

And you took advantage of util/parse-events.l being
the first dependency to replace it with $<

So I think you can have it as:

$(OUTPUT)util/parse-events-flex.c $(OUTPUT)util/parse-events-flex.h: util/parse-events.l $(OUTPUT)util/parse-events-bison.c
$(call rule_mkdir)
$(Q)$(call echo-cmd,flex)$(FLEX) -o $@ --header-file=$(OUTPUT)util/parse-events-flex.h $(PARSER_DEBUG_FLEX) $< \
--header-file=$(OUTPUT)util/parse-events-flex.h

Right?

You have $(OUTPUT)util/parse-events-flex.h later on as a dependency, but
by then this has resolved already and that recipe won't be called for
it?

Damn, Makefiles are obtuse, we better do this more piecemeal, for
instance, using $< where applicable first, etc.

This will help us bisect problems here,

Thanks,

- Arnaldo

> -$(OUTPUT)util/parse-events-bison.c: util/parse-events.y
> +$(OUTPUT)util/parse-events-bison.c $(OUTPUT)util/parse-events-bison.h: util/parse-events.y
> $(call rule_mkdir)
> - $(Q)$(call echo-cmd,bison)$(BISON) -v util/parse-events.y -d $(PARSER_DEBUG_BISON) -o $@ -p parse_events_
> + $(Q)$(call echo-cmd,bison)$(BISON) -v util/parse-events.y \
> + $(PARSER_DEBUG_BISON) -o $(OUTPUT)util/parse-events-bison.c \
> + --defines=$(OUTPUT)util/parse-events-bison.h \
> + -p parse_events_
>
> -$(OUTPUT)util/expr-flex.c: util/expr.l $(OUTPUT)util/expr-bison.c
> +$(OUTPUT)util/parse-events-bison.o: $(OUTPUT)util/parse-events-flex.h
> +
> +$(OUTPUT)util/expr-flex.c $(OUTPUT)util/expr-flex.h: util/expr.l $(OUTPUT)util/expr-bison.c
> $(call rule_mkdir)
> - $(Q)$(call echo-cmd,flex)$(FLEX) -o $@ --header-file=$(OUTPUT)util/expr-flex.h $(PARSER_DEBUG_FLEX) util/expr.l
> + $(Q)$(call echo-cmd,flex)$(FLEX) -o $(OUTPUT)util/expr-flex.c \
> + --header-file=$(OUTPUT)util/expr-flex.h $(PARSER_DEBUG_FLEX) $<
>
> -$(OUTPUT)util/expr-bison.c: util/expr.y
> +$(OUTPUT)util/expr-bison.c $(OUTPUT)util/expr-bison.h: util/expr.y
> $(call rule_mkdir)
> - $(Q)$(call echo-cmd,bison)$(BISON) -v util/expr.y -d $(PARSER_DEBUG_BISON) -o $@ -p expr_
> + $(Q)$(call echo-cmd,bison)$(BISON) -v util/expr.y $(PARSER_DEBUG_BISON) \
> + -o $(OUTPUT)util/expr-bison.c \
> + --defines=$(OUTPUT)util/expr-bison.h -p expr_
> +
> +$(OUTPUT)util/expr-bison.o: $(OUTPUT)util/expr-flex.h
>
> -$(OUTPUT)util/pmu-flex.c: util/pmu.l $(OUTPUT)util/pmu-bison.c
> +$(OUTPUT)util/pmu-flex.c $(OUTPUT)util/pmu-flex.h: util/pmu.l $(OUTPUT)util/pmu-bison.c
> $(call rule_mkdir)
> - $(Q)$(call echo-cmd,flex)$(FLEX) -o $@ --header-file=$(OUTPUT)util/pmu-flex.h util/pmu.l
> + $(Q)$(call echo-cmd,flex)$(FLEX) -o $(OUTPUT)util/pmu-flex.c \
> + --header-file=$(OUTPUT)util/pmu-flex.h $(PARSER_DEBUG_FLEX) $<
>
> -$(OUTPUT)util/pmu-bison.c: util/pmu.y
> +$(OUTPUT)util/pmu-bison.c $(OUTPUT)util/pmu-bison.h: util/pmu.y
> $(call rule_mkdir)
> - $(Q)$(call echo-cmd,bison)$(BISON) -v util/pmu.y -d -o $@ -p perf_pmu_
> -
> -CFLAGS_parse-events-flex.o += -w
> -CFLAGS_pmu-flex.o += -w
> -CFLAGS_expr-flex.o += -w
> -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
> + $(Q)$(call echo-cmd,bison)$(BISON) -v util/pmu.y $(PARSER_DEBUG_BISON) \
> + -o $(OUTPUT)util/pmu-bison.c \
> + --defines=$(OUTPUT)util/pmu-bison.h -p perf_pmu_
> +
> +flex_flags := -Wno-switch-enum -Wno-switch-default -Wno-unused-function -Wno-redundant-decls
> +bison_flags := -Wno-unused-parameter -Wno-nested-externs
> +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 $(bison_flags)
> +CFLAGS_pmu-bison.o += -DYYENABLE_NLS=0 -DYYLTYPE_IS_TRIVIAL=0 $(bison_flags)
> +CFLAGS_expr-bison.o += -DYYENABLE_NLS=0 -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
> diff --git a/tools/perf/util/expr.y b/tools/perf/util/expr.y
> index bf3e898e3055..f34a5e544a41 100644
> --- a/tools/perf/util/expr.y
> +++ b/tools/perf/util/expr.y
> @@ -39,6 +39,8 @@
> %type <num> expr if_expr
>
> %{
> +#include "expr-flex.h"
> +
> static void expr_error(double *final_val __maybe_unused,
> struct expr_parse_ctx *ctx __maybe_unused,
> void *scanner,
> diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
> index acef87d9af58..ae0aa47dbafb 100644
> --- a/tools/perf/util/parse-events.y
> +++ b/tools/perf/util/parse-events.y
> @@ -17,6 +17,7 @@
> #include "evsel.h"
> #include "parse-events.h"
> #include "parse-events-bison.h"
> +#include "parse-events-flex.h"
>
> void parse_events_error(YYLTYPE *loc, void *parse_state, void *scanner, char const *msg);
>
> --
> 2.27.0.278.ge193c7cf3a9-goog
>

--

- Arnaldo

Next message: Qi Zheng: "[PATCH] sched/fair: Fix comment in newidle_balance()"
Previous message: Shuah Khan: "Re: [PATCH 4.14 00/46] 4.14.184-rc2 review"
In reply to: Ian Rogers: "[PATCH 2/2] perf parse-events: enable more flex/yacc warnings"
Next in thread: Arnaldo Carvalho de Melo: "Re: [PATCH 2/2] perf parse-events: enable more flex/yacc warnings"
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