perf trace: Introduce trace__btf_scnprintf()

To have a central place that will look at the BTF type and call the
right scnprintf routine or return zero, meaning BTF pretty printing
isn't available or not implemented for a specific type.
Signed-off-by: Howard Chu <howardchu95@gmail.com>
Tested-by: Howard Chu <howardchu95@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240624181345.124764-8-howardchu95@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-trace.c

@@ -981,18 +981,28 @@ static size_t btf_enum_scnprintf(const struct btf_type *type, struct btf *btf, c
 static size_t trace__btf_enum_scnprintf(struct trace *trace, struct syscall_arg_fmt *arg_fmt, char *bf,
 					size_t size, int val, char *type)
 {
-	if (trace->btf == NULL)
-		return 0;
-
 	if (syscall_arg_fmt__cache_btf_enum(arg_fmt, trace->btf, type) < 0)
 		return 0;
 
 	return btf_enum_scnprintf(arg_fmt->type, trace->btf, bf, size, val);
 }
+
+static size_t trace__btf_scnprintf(struct trace *trace, struct syscall_arg_fmt *arg_fmt, char *bf,
+				   size_t size, int val, char *type)
+{
+	if (trace->btf == NULL)
+		return 0;
+
+	if (arg_fmt->is_enum)
+		return trace__btf_enum_scnprintf(trace, arg_fmt, bf, size, val, type);
+
+	return 0;
+}
+
 #else // HAVE_LIBBPF_SUPPORT
-static size_t trace__btf_enum_scnprintf(struct trace *trace __maybe_unused, struct syscall_arg_fmt *arg_fmt __maybe_unused,
-					char *bf __maybe_unused, size_t size __maybe_unused, int val __maybe_unused,
-					char *type __maybe_unused)
+static size_t trace__btf_scnprintf(struct trace *trace __maybe_unused, struct syscall_arg_fmt *arg_fmt __maybe_unused,
+				   char *bf __maybe_unused, size_t size __maybe_unused, int val __maybe_unused,
+				   char *type __maybe_unused)
 {
 	return 0;
 }
@@ -2183,7 +2193,7 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
 				      unsigned char *args, void *augmented_args, int augmented_args_size,
 				      struct trace *trace, struct thread *thread)
 {
-	size_t printed = 0;
+	size_t printed = 0, btf_printed;
 	unsigned long val;
 	u8 bit = 1;
 	struct syscall_arg arg = {
@@ -2237,13 +2247,11 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
 			if (trace->show_arg_names)
 				printed += scnprintf(bf + printed, size - printed, "%s: ", field->name);
 
-			if (sc->arg_fmt[arg.idx].is_enum) {
-				size_t p = trace__btf_enum_scnprintf(trace, &sc->arg_fmt[arg.idx], bf + printed,
-								     size - printed, val, field->type);
-				if (p) {
-					printed += p;
-					continue;
-				}
+			btf_printed = trace__btf_scnprintf(trace, &sc->arg_fmt[arg.idx], bf + printed,
+							   size - printed, val, field->type);
+			if (btf_printed) {
+				printed += btf_printed;
+				continue;
 			}
 
 			printed += syscall_arg_fmt__scnprintf_val(&sc->arg_fmt[arg.idx],
@@ -2892,7 +2900,7 @@ static size_t trace__fprintf_tp_fields(struct trace *trace, struct evsel *evsel,
 	size_t size = sizeof(bf);
 	struct tep_format_field *field = evsel->tp_format->format.fields;
 	struct syscall_arg_fmt *arg = __evsel__syscall_arg_fmt(evsel);
-	size_t printed = 0;
+	size_t printed = 0, btf_printed;
 	unsigned long val;
 	u8 bit = 1;
 	struct syscall_arg syscall_arg = {
@@ -2942,13 +2950,10 @@ static size_t trace__fprintf_tp_fields(struct trace *trace, struct evsel *evsel,
 		if (trace->show_arg_names)
 			printed += scnprintf(bf + printed, size - printed, "%s: ", field->name);
 
-		if (arg->is_enum) {
-			size_t p = trace__btf_enum_scnprintf(trace, arg, bf + printed,
-							     size - printed, val, field->type);
-			if (p) {
-				printed += p;
-				continue;
-			}
+		btf_printed = trace__btf_scnprintf(trace, arg, bf + printed, size - printed, val, field->type);
+		if (btf_printed) {
+			printed += btf_printed;
+			continue;
 		}
 
 		printed += syscall_arg_fmt__scnprintf_val(arg, bf + printed, size - printed, &syscall_arg, val);