perf expr: Add expr_scanner_ctx object

Add the expr_scanner_ctx object to hold user data for the expr scanner.
Currently it holds only start_token, Kajol Jain will use it to hold 24x7
runtime param.

Signed-off-by: Jiri Olsa <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: Anju T Sudhakar <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Jin Yao <[e-mail]>
Cc: Joe Mario <[e-mail]>
Cc: Kajol Jain <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Madhavan Srinivasan <[e-mail]>
Cc: Mamatha Inamdar <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Michael Petlan <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Ravi Bangoria <[e-mail]>
Cc: Sukadev Bhattiprolu <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: [e-mail]
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/expr.c

···
 #include <assert.h>
 #include "expr.h"
 #include "expr-bison.h"
-#define YY_EXTRA_TYPE int
 #include "expr-flex.h"
 
 #ifdef PARSER_DEBUG
···
 __expr__parse(double *val, struct expr_parse_ctx *ctx, const char *expr,
 	      int start)
 {
+	struct expr_scanner_ctx scanner_ctx = {
+		.start_token = start,
+	};
 	YY_BUFFER_STATE buffer;
 	void *scanner;
 	int ret;
 
-	ret = expr_lex_init_extra(start, &scanner);
+	ret = expr_lex_init_extra(&scanner_ctx, &scanner);
 	if (ret)
 		return ret;
 

tools/perf/util/expr.h

···
 	struct expr_parse_id ids[MAX_PARSE_ID];
 };
 
+struct expr_scanner_ctx {
+	int start_token;
+};
+
 void expr__ctx_init(struct expr_parse_ctx *ctx);
 void expr__add_id(struct expr_parse_ctx *ctx, const char *id, double val);
 int expr__parse(double *final_val, struct expr_parse_ctx *ctx, const char *expr);

tools/perf/util/expr.l

···
 symbol		{spec}*{sym}*{spec}*{sym}*
 
 %%
+	struct expr_scanner_ctx *sctx = expr_get_extra(yyscanner);
+
 	{
-		int start_token;
+		int start_token = sctx->start_token;
 
-		start_token = expr_get_extra(yyscanner);
-
-		if (start_token) {
-			expr_set_extra(NULL, yyscanner);
+		if (sctx->start_token) {
+			sctx->start_token = 0;
 			return start_token;
 		}
 	}