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

Ian Rogers
2023-04-06T06:52:49Z

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>
---
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