perf pmu: Make parser reentrant

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>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Gaosheng Cui <cuigaosheng1@huawei.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230406065224.2553640-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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);

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);

tools/perf/util/pmu.l

@@ -1,21 +1,28 @@
 %option prefix="perf_pmu_"
+%option reentrant
+%option bison-bridge
 
 %{
 #include <stdlib.h>
 #include <linux/bitops.h>
 #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;
 }

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)
 {
 }