perf trace: Allow allocating sc->arg_fmt even without the syscall tracepoint

At least "clone" doesn't have (enter, exit) entries tracefs/events/syscalls/,
but we can provide a syscall_fmt and use it instead, as will be done for
"clone" in the next cset.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-o12kejgcxddyovn2hlg4gbim@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 4370ce4f28c7899447a3369ffd19acf4ac6b822c..1c5238af6d14f955c8c66e7feb58f6c51bda6f7d 100644 (file)
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1165,22 +1165,31 @@ static int trace__symbols_init(struct trace *trace, struct perf_evlist *evlist)
        return err;
 }
 
-static int syscall__set_arg_fmts(struct syscall *sc)
+static int syscall__alloc_arg_fmts(struct syscall *sc, int nr_args)
 {
-       struct format_field *field;
-       int idx = 0, len;
+       int idx;
 
-       sc->arg_fmt = calloc(sc->nr_args, sizeof(*sc->arg_fmt));
+       sc->arg_fmt = calloc(nr_args, sizeof(*sc->arg_fmt));
        if (sc->arg_fmt == NULL)
                return -1;
 
-       for (field = sc->args; field; field = field->next, ++idx) {
-               if (sc->fmt) {
+       for (idx = 0; idx < nr_args; ++idx) {
+               if (sc->fmt)
                        sc->arg_fmt[idx] = sc->fmt->arg[idx];
+       }
 
-                       if (sc->fmt->arg[idx].scnprintf)
-                               continue;
-               }
+       sc->nr_args = nr_args;
+       return 0;
+}
+
+static int syscall__set_arg_fmts(struct syscall *sc)
+{
+       struct format_field *field;
+       int idx = 0, len;
+
+       for (field = sc->args; field; field = field->next, ++idx) {
+               if (sc->fmt && sc->fmt->arg[idx].scnprintf)
+                       continue;
 
                if (strcmp(field->type, "const char *") == 0 &&
                         (strcmp(field->name, "filename") == 0 ||
@@ -1251,11 +1260,13 @@ static int trace__read_syscall_info(struct trace *trace, int id)
                sc->tp_format = trace_event__tp_format("syscalls", tp_name);
        }
 
+       if (syscall__alloc_arg_fmts(sc, IS_ERR(sc->tp_format) ? 6 : sc->tp_format->format.nr_fields))
+               return -1;
+
        if (IS_ERR(sc->tp_format))
                return -1;
 
        sc->args = sc->tp_format->format.fields;
-       sc->nr_args = sc->tp_format->format.nr_fields;
        /*
         * We need to check and discard the first variable '__syscall_nr'
         * or 'nr' that mean the syscall number. It is needless here.