linux-kernel - [PATCH v1] perf parse-events: Tidy name token matching

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Message-Id: <20250109175401.161340-1-irogers@google.com>
Date: Thu,  9 Jan 2025 09:54:01 -0800
From: Ian Rogers <irogers@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	Kan Liang <kan.liang@...ux.intel.com>, Andi Kleen <ak@...ux.intel.com>, 
	Dominique Martinet <asmadeus@...ewreck.org>, linux-perf-users@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: [PATCH v1] perf parse-events: Tidy name token matching

Prior to commit 70c90e4a6b2f ("perf parse-events: Avoid scanning PMUs
before parsing") names (generally event names) excluded hyphen (minus)
symbols as the formation of legacy names with hyphens was handled in
the yacc code. That commit allowed hyphens supposedly making
name_minus unnecessary. However, changing name_minus to name has
issues in the term config tokens as then name ends up having priority
over numbers and name allows matching numbers since commit
5ceb57990bf4 ("perf parse: Allow tracepoint names to start with digits
"). It is also permissable for a name to match with a colon (':') in
it when its in a config term list. To address this rename name_minus
to term_name, make the pattern match name's except for the colon, add
number matching into the config term region with a higher priority
than name matching. This addresses an inconsistency and allows greater
matching for names inside of term lists, for example, they may start
with a number.

Rename name_tag to quoted_name and update comments and helper
functions to avoid str detecting quoted strings which was already done
by the lexer.

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/util/parse-events.l | 51 +++++++++++++++++++++-------------
 1 file changed, 32 insertions(+), 19 deletions(-)

diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index bf7f73548605..7ed86e3e34e3 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -53,21 +53,25 @@ static int str(yyscan_t scanner, int token)
 	YYSTYPE *yylval = parse_events_get_lval(scanner);
 	char *text = parse_events_get_text(scanner);
 
-	if (text[0] != '\'') {
-		yylval->str = strdup(text);
-	} else {
-		/*
-		 * If a text tag specified on the command line
-		 * contains opening single quite ' then it is
-		 * expected that the tag ends with single quote
-		 * as well, like this:
-		 *     name=\'CPU_CLK_UNHALTED.THREAD:cmask=1\'
-		 * quotes need to be escaped to bypass shell
-		 * processing.
-		 */
-		yylval->str = strndup(&text[1], strlen(text) - 2);
-	}
+	yylval->str = strdup(text);
+	return token;
+}
+
+static int quoted_str(yyscan_t scanner, int token)
+{
+	YYSTYPE *yylval = parse_events_get_lval(scanner);
+	char *text = parse_events_get_text(scanner);
 
+	/*
+	 * If a text tag specified on the command line
+	 * contains opening single quite ' then it is
+	 * expected that the tag ends with single quote
+	 * as well, like this:
+	 *     name=\'CPU_CLK_UNHALTED.THREAD:cmask=1\'
+	 * quotes need to be escaped to bypass shell
+	 * processing.
+	 */
+	yylval->str = strndup(&text[1], strlen(text) - 2);
 	return token;
 }
 
@@ -235,9 +239,16 @@ event		[^,{}/]+
 num_dec		[0-9]+
 num_hex		0x[a-fA-F0-9]{1,16}
 num_raw_hex	[a-fA-F0-9]{1,16}
-name		[a-zA-Z0-9_*?\[\]][a-zA-Z0-9_*?.\[\]!\-]*
-name_tag	[\'][a-zA-Z0-9_*?\[\]][a-zA-Z0-9_*?\-,\.\[\]:=]*[\']
-name_minus	[a-zA-Z_*?][a-zA-Z0-9\-_*?.:]*
+/* Regular pattern to match the token PE_NAME. */
+name_start      [a-zA-Z0-9_*?\[\]]
+name		{name_start}[a-zA-Z0-9_*?.\[\]!\-]*
+/* PE_NAME token when inside a config term list, allows ':'. */
+term_name	{name_start}[a-zA-Z0-9_*?.\[\]!\-:]*
+/*
+ * PE_NAME token when quoted, allows ':,.='.
+ * Matches the RHS of terms like: name='COMPLEX_CYCLES_NAME:orig=cycles,desc=chip-clock-ticks'.
+ */
+quoted_name	[\']{name_start}[a-zA-Z0-9_*?.\[\]!\-:,\.=]*[\']
 drv_cfg_term	[a-zA-Z0-9_\.]+(=[a-zA-Z0-9_*?\.:]+)?
 /*
  * If you add a modifier you need to update check_modifier().
@@ -341,7 +352,9 @@ r0x{num_raw_hex}	{ return str(yyscanner, PE_RAW); }
 {lc_type}			{ return lc_str(yyscanner, _parse_state); }
 {lc_type}-{lc_op_result}	{ return lc_str(yyscanner, _parse_state); }
 {lc_type}-{lc_op_result}-{lc_op_result}	{ return lc_str(yyscanner, _parse_state); }
-{name_minus}		{ return str(yyscanner, PE_NAME); }
+{num_dec}		{ return value(_parse_state, yyscanner, 10); }
+{num_hex}		{ return value(_parse_state, yyscanner, 16); }
+{term_name}		{ return str(yyscanner, PE_NAME); }
 @{drv_cfg_term}		{ return drv_str(yyscanner, PE_DRV_CFG_TERM); }
 }
 
@@ -410,7 +423,7 @@ r{num_raw_hex}		{ return str(yyscanner, PE_RAW); }
 
 {modifier_event}	{ return modifiers(_parse_state, yyscanner); }
 {name}			{ return str(yyscanner, PE_NAME); }
-{name_tag}		{ return str(yyscanner, PE_NAME); }
+{quoted_name}		{ return quoted_str(yyscanner, PE_NAME); }
 "/"			{ BEGIN(config); return '/'; }
 ,			{ BEGIN(event); return ','; }
 :			{ return ':'; }
-- 
2.47.1.613.gc27f4b7a9f-goog