perf trace: Use evsel->handler.func

I.e. we don't need to resolve the evsel via the id and then check if it
is this or that event, just stash the right handler at evsel creation
time, then use evsel->handler.func() straight away.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-bpz3axzr4f2cjppf4egm28wf@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-trace.c

@@ -114,10 +114,85 @@ static size_t syscall__fprintf_args(struct syscall *sc, unsigned long *args, FIL
 	return printed;
 }
 
+typedef int (*tracepoint_handler)(struct trace *trace, struct perf_evsel *evsel,
+				  struct perf_sample *sample);
+
+static struct syscall *trace__syscall_info(struct trace *trace,
+					   struct perf_evsel *evsel,
+					   struct perf_sample *sample)
+{
+	int id = perf_evsel__intval(evsel, sample, "id");
+
+	if (id < 0) {
+		printf("Invalid syscall %d id, skipping...\n", id);
+		return NULL;
+	}
+
+	if ((id > trace->syscalls.max || trace->syscalls.table[id].name == NULL) &&
+	    trace__read_syscall_info(trace, id))
+		goto out_cant_read;
+
+	if ((id > trace->syscalls.max || trace->syscalls.table[id].name == NULL))
+		goto out_cant_read;
+
+	return &trace->syscalls.table[id];
+
+out_cant_read:
+	printf("Problems reading syscall %d information\n", id);
+	return NULL;
+}
+
+static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
+			    struct perf_sample *sample)
+{
+	void *args;
+	struct syscall *sc = trace__syscall_info(trace, evsel, sample);
+
+	if (sc == NULL)
+		return -1;
+
+	args = perf_evsel__rawptr(evsel, sample, "args");
+	if (args == NULL) {
+		printf("Problems reading syscall arguments\n");
+		return -1;
+	}
+
+	printf("%s(", sc->name);
+	syscall__fprintf_args(sc, args, stdout);
+
+	return 0;
+}
+
+static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
+			   struct perf_sample *sample)
+{
+	int ret;
+	struct syscall *sc = trace__syscall_info(trace, evsel, sample);
+
+	if (sc == NULL)
+		return -1;
+
+	ret = perf_evsel__intval(evsel, sample, "ret");
+
+	if (ret < 0 && sc->fmt && sc->fmt->errmsg) {
+		char bf[256];
+		const char *emsg = strerror_r(-ret, bf, sizeof(bf)),
+			   *e = audit_errno_to_name(-ret);
+
+		printf(") = -1 %s %s", e, emsg);
+	} else if (ret == 0 && sc->fmt && sc->fmt->timeout)
+		printf(") = 0 Timeout");
+	else
+		printf(") = %d", ret);
+
+	putchar('\n');
+	return 0;
+}
+
 static int trace__run(struct trace *trace)
 {
 	struct perf_evlist *evlist = perf_evlist__new(NULL, NULL);
-	struct perf_evsel *evsel, *evsel_enter, *evsel_exit;
+	struct perf_evsel *evsel;
 	int err = -1, i, nr_events = 0, before;
 
 	if (evlist == NULL) {
@@ -125,21 +200,23 @@ static int trace__run(struct trace *trace)
 		goto out;
 	}
 
-	evsel_enter = perf_evsel__newtp("raw_syscalls", "sys_enter", 0);
-	if (evsel_enter == NULL) {
+	evsel = perf_evsel__newtp("raw_syscalls", "sys_enter", 0);
+	if (evsel == NULL) {
 		printf("Couldn't read the raw_syscalls:sys_enter tracepoint information!\n");
 		goto out_delete_evlist;
 	}
 
-	perf_evlist__add(evlist, evsel_enter);
+	evsel->handler.func = trace__sys_enter;
+	perf_evlist__add(evlist, evsel);
 
-	evsel_exit = perf_evsel__newtp("raw_syscalls", "sys_exit", 1);
-	if (evsel_exit == NULL) {
+	evsel = perf_evsel__newtp("raw_syscalls", "sys_exit", 1);
+	if (evsel == NULL) {
 		printf("Couldn't read the raw_syscalls:sys_exit tracepoint information!\n");
 		goto out_delete_evlist;
 	}
 
-	perf_evlist__add(evlist, evsel_exit);
+	evsel->handler.func = trace__sys_exit;
+	perf_evlist__add(evlist, evsel);
 
 	err = perf_evlist__create_maps(evlist, &trace->opts.target);
 	if (err < 0) {
@@ -170,9 +247,8 @@ again:
 
 		while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) {
 			const u32 type = event->header.type;
-			struct syscall *sc;
+			tracepoint_handler handler;
 			struct perf_sample sample;
-			int id;
 
 			++nr_events;
 
@@ -200,45 +276,11 @@ again:
 				continue;
 			}
 
-			id = perf_evsel__intval(evsel, &sample, "id");
-			if (id < 0) {
-				printf("Invalid syscall %d id, skipping...\n", id);
-				continue;
-			}
-
-			if ((id > trace->syscalls.max || trace->syscalls.table[id].name == NULL) &&
-			    trace__read_syscall_info(trace, id))
-				continue;
-
-			if ((id > trace->syscalls.max || trace->syscalls.table[id].name == NULL))
-				continue;
-
-			sc = &trace->syscalls.table[id];
-
 			if (evlist->threads->map[0] == -1 || evlist->threads->nr > 1)
 				printf("%d ", sample.tid);
 
-			if (evsel == evsel_enter) {
-				void *args = perf_evsel__rawptr(evsel, &sample, "args");
-
-				printf("%s(", sc->name);
-				syscall__fprintf_args(sc, args, stdout);
-			} else if (evsel == evsel_exit) {
-				int ret = perf_evsel__intval(evsel, &sample, "ret");
-
-				if (ret < 0 && sc->fmt && sc->fmt->errmsg) {
-					char bf[256];
-					const char *emsg = strerror_r(-ret, bf, sizeof(bf)),
-						   *e = audit_errno_to_name(-ret);
-
-					printf(") = -1 %s %s", e, emsg);
-				} else if (ret == 0 && sc->fmt && sc->fmt->timeout)
-					printf(") = 0 Timeout");
-				else
-					printf(") = %d", ret);
-
-				putchar('\n');
-			}
+			handler = evsel->handler.func;
+			handler(trace, evsel, &sample);
 		}
 	}