perf parse-events: Avoid scanning PMUs before parsing

The event parser needs to handle two special cases:
1) legacy events like L1-dcache-load-miss. These event names don't
   appear in JSON or sysfs, and lookup tables are used for the config
   value.
2) raw events where 'r0xead' is the same as 'read' unless the PMU has
   an event called 'read' in which case the event has priority.

The previous parser to handle these cases would scan all PMUs for
components of event names. These components would then be used to
classify in the lexer whether the token should be part of a legacy
event, a raw event or an event. The grammar would handle legacy event
tokens or recombining the tokens back into a regular event name.  The
code wasn't PMU specific and had issues around events like AMD's
branch-brs that would fail to parse as it expects brs to be a suffix
on a legacy event style name:

$ perf stat -e branch-brs true
event syntax error: 'branch-brs'
                           \___ parser error

This change removes processing all PMUs by using the lexer in the form
of a regular expression matcher. The lexer will return the token for
the longest matched sequence of characters, and in the event of a tie
the first. The legacy events are a fixed number of regular
expressions, and by matching these before a name token its possible to
generate an accurate legacy event token with everything else matching
as a name. Because of the lexer change the handling of hyphens in the
grammar can be removed as hyphens just become a part of the name.

To handle raw events and terms the parser is changed to defer trying
to evaluate whether something is a raw event until the PMU is known in
the grammar. Once the PMU is known, the events of the PMU can be
scanned for the 'read' style problem. A new term type is added for
these raw terms, used to enable deferring the evaluation.

While this change is large, it has stats of:
170 insertions(+), 436 deletions(-)
the bulk of the change is deleting the old approach. It isn't possible
to break apart the code added due to the dependencies on how the parts
of the parsing work.

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ahmad Yasin <ahmad.yasin@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: Edward Baker <edward.baker@intel.com>
Cc: Florian Fischer <florian.fischer@muhq.space>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kang Minchul <tegongkang@gmail.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Perry Taylor <perry.taylor@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Samantha Alt <samantha.alt@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Weilin Wang <weilin.wang@intel.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Link: https://lore.kernel.org/r/20230502223851.2234828-19-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 2 insertions, 14 deletions

diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index 86ad4438a2aa..f638542c8638 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -41,14 +41,6 @@ int parse_events_terms(struct list_head *terms, const char *str);
 int parse_filter(const struct option *opt, const char *str, int unset);
 int exclude_perf(const struct option *opt, const char *arg, int unset);
 
-enum perf_pmu_event_symbol_type {
-	PMU_EVENT_SYMBOL_ERR,		/* not a PMU EVENT */
-	PMU_EVENT_SYMBOL,		/* normal style PMU event */
-	PMU_EVENT_SYMBOL_PREFIX,	/* prefix of pre-suf style event */
-	PMU_EVENT_SYMBOL_SUFFIX,	/* suffix of pre-suf style event */
-	PMU_EVENT_SYMBOL_SUFFIX2,	/* suffix of pre-suf2 style event */
-};
-
 enum {
 	PARSE_EVENTS__TERM_TYPE_NUM,
 	PARSE_EVENTS__TERM_TYPE_STR,
@@ -78,6 +70,7 @@ enum {
 	PARSE_EVENTS__TERM_TYPE_AUX_OUTPUT,
 	PARSE_EVENTS__TERM_TYPE_AUX_SAMPLE_SIZE,
 	PARSE_EVENTS__TERM_TYPE_METRIC_ID,
+	PARSE_EVENTS__TERM_TYPE_RAW,
 	__PARSE_EVENTS__TERM_TYPE_NR,
 };
 
@@ -174,8 +167,7 @@ int parse_events_add_numeric(struct parse_events_state *parse_state,
 int parse_events_add_tool(struct parse_events_state *parse_state,
 			  struct list_head *list,
 			  int tool_event);
-int parse_events_add_cache(struct list_head *list, int *idx,
-			   char *type, char *op_result1, char *op_result2,
+int parse_events_add_cache(struct list_head *list, int *idx, const char *name,
 			   struct parse_events_error *error,
 			   struct list_head *head_config,
 			   struct parse_events_state *parse_state);
@@ -198,8 +190,6 @@ int parse_events_multi_pmu_add(struct parse_events_state *parse_state,
 int parse_events_copy_term_list(struct list_head *old,
 				 struct list_head **new);
 
-enum perf_pmu_event_symbol_type
-perf_pmu__parse_check(const char *name);
 void parse_events__set_leader(char *name, struct list_head *list);
 void parse_events_update_lists(struct list_head *list_event,
 			       struct list_head *list_all);
@@ -241,8 +231,6 @@ static inline bool is_sdt_event(char *str __maybe_unused)
 }
 #endif /* HAVE_LIBELF_SUPPORT */
 
-int perf_pmu__test_parse_init(void);
-
 struct evsel *parse_events__add_event_hybrid(struct list_head *list, int *idx,
 					     struct perf_event_attr *attr,
 					     const char *name,