Re: [PATCH v3 1/2] perf pmu: Make parser reentrant

Jiri Olsa
2023-04-06T21:42:01Z

On Wed, Apr 05, 2023 at 11:52:23PM -0700, Ian Rogers wrote:
> By default bison uses global state for compatibility with yacc. Make
> the parser reentrant so that it may be used in asynchronous and
> multithreaded situations.
>
> Signed-off-by: Ian Rogers <irogers@google.com>

Acked-by: Jiri Olsa <jolsa@kernel.org>

jirka

> ---
> tools/perf/util/pmu.c | 26 ++++++++++++++++++++------
> tools/perf/util/pmu.h | 2 +-
> tools/perf/util/pmu.l | 17 ++++++++++++-----
> tools/perf/util/pmu.y | 5 ++++-
> 4 files changed, 37 insertions(+), 13 deletions(-)
>
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 78a407b42ad1..96ef317bac41 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -24,6 +24,8 @@
> #include "evsel.h"
> #include "pmu.h"
> #include "pmus.h"
> +#include "pmu-bison.h"
> +#include "pmu-flex.h"
> #include "parse-events.h"
> #include "print-events.h"
> #include "header.h"
> @@ -57,9 +59,6 @@ struct perf_pmu_format {
> struct list_head list;
> };
>
> -int perf_pmu_parse(struct list_head *list, char *name);
> -extern FILE *perf_pmu_in;
> -
> static bool hybrid_scanned;
>
> static struct perf_pmu *perf_pmu__find2(int dirfd, const char *name);
> @@ -81,6 +80,8 @@ int perf_pmu__format_parse(int dirfd, struct list_head *head)
> while (!ret && (evt_ent = readdir(format_dir))) {
> char *name = evt_ent->d_name;
> int fd;
> + void *scanner;
> + FILE *file;
>
> if (!strcmp(name, ".") || !strcmp(name, ".."))
> continue;
> @@ -91,9 +92,22 @@ int perf_pmu__format_parse(int dirfd, struct list_head *head)
> if (fd < 0)
> break;
>
> - perf_pmu_in = fdopen(fd, "r");
> - ret = perf_pmu_parse(head, name);
> - fclose(perf_pmu_in);
> + file = fdopen(fd, "r");
> + if (!file) {
> + close(fd);
> + break;
> + }
> +
> + ret = perf_pmu_lex_init(&scanner);
> + if (ret) {
> + fclose(file);
> + break;
> + }
> +
> + perf_pmu_set_in(file, scanner);
> + ret = perf_pmu_parse(head, name, scanner);
> + perf_pmu_lex_destroy(scanner);
> + fclose(file);
> }
>
> closedir(format_dir);
> diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
> index 32c3a75bca0e..d53618c65c92 100644
> --- a/tools/perf/util/pmu.h
> +++ b/tools/perf/util/pmu.h
> @@ -206,7 +206,7 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms,
> struct perf_pmu_info *info);
> struct list_head *perf_pmu__alias(struct perf_pmu *pmu,
> struct list_head *head_terms);
> -void perf_pmu_error(struct list_head *list, char *name, char const *msg);
> +void perf_pmu_error(struct list_head *list, char *name, void *scanner, char const *msg);
>
> int perf_pmu__new_format(struct list_head *list, char *name,
> int config, unsigned long *bits);
> diff --git a/tools/perf/util/pmu.l b/tools/perf/util/pmu.l
> index 58b4926cfaca..67b247be693b 100644
> --- a/tools/perf/util/pmu.l
> +++ b/tools/perf/util/pmu.l
> @@ -1,4 +1,6 @@
> %option prefix="perf_pmu_"
> +%option reentrant
> +%option bison-bridge
>
> %{
> #include <stdlib.h>
> @@ -6,16 +8,21 @@
> #include "pmu.h"
> #include "pmu-bison.h"
>
> -static int value(int base)
> +char *perf_pmu_get_text(yyscan_t yyscanner);
> +YYSTYPE *perf_pmu_get_lval(yyscan_t yyscanner);
> +
> +static int value(yyscan_t scanner, int base)
> {
> + YYSTYPE *yylval = perf_pmu_get_lval(scanner);
> + char *text = perf_pmu_get_text(scanner);
> long num;
>
> errno = 0;
> - num = strtoul(perf_pmu_text, NULL, base);
> + num = strtoul(text, NULL, base);
> if (errno)
> return PP_ERROR;
>
> - perf_pmu_lval.num = num;
> + yylval->num = num;
> return PP_VALUE;
> }
>
> @@ -25,7 +32,7 @@ num_dec [0-9]+
>
> %%
>
> -{num_dec} { return value(10); }
> +{num_dec} { return value(yyscanner, 10); }
> config { return PP_CONFIG; }
> - { return '-'; }
> : { return ':'; }
> @@ -35,7 +42,7 @@ config { return PP_CONFIG; }
>
> %%
>
> -int perf_pmu_wrap(void)
> +int perf_pmu_wrap(void *scanner __maybe_unused)
> {
> return 1;
> }
> diff --git a/tools/perf/util/pmu.y b/tools/perf/util/pmu.y
> index e675d79a0274..dff4e892ac4d 100644
> --- a/tools/perf/util/pmu.y
> +++ b/tools/perf/util/pmu.y
> @@ -1,6 +1,8 @@
> -
> +%define api.pure full
> %parse-param {struct list_head *format}
> %parse-param {char *name}
> +%parse-param {void *scanner}
> +%lex-param {void* scanner}
>
> %{
>
> @@ -78,6 +80,7 @@ PP_VALUE
>
> void perf_pmu_error(struct list_head *list __maybe_unused,
> char *name __maybe_unused,
> + void *scanner __maybe_unused,
> char const *msg __maybe_unused)
> {
> }
> --
> 2.40.0.348.gf938b09366-goog
>