perf trace: When showing string prefixes show prefix + ??? for unknown entries

To match 'strace' output, like in:

  arch_prctl(0x3001 /* ARCH_??? */, 0x7ffc8a92dc80) = -1 EINVAL (Invalid argument)

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-kx59j2dk5l1x04ou57mt99ck@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 9d30e0f..6d9be95 100644 (file)
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -365,8 +365,12 @@ size_t strarray__scnprintf(struct strarray *sa, char *bf, size_t size, const cha
 {
        int idx = val - sa->offset;
 
-       if (idx < 0 || idx >= sa->nr_entries || sa->entries[idx] == NULL)
-               return scnprintf(bf, size, intfmt, val);
+       if (idx < 0 || idx >= sa->nr_entries || sa->entries[idx] == NULL) {
+               size_t printed = scnprintf(bf, size, intfmt, val);
+               if (show_prefix)
+                       printed += scnprintf(bf + printed, size - printed, " /* %s??? */", sa->prefix);
+               return printed;
+       }
 
        return scnprintf(bf, size, "%s%s", show_prefix ? sa->prefix : "", sa->entries[idx]);
 }
@@ -388,6 +392,7 @@ static size_t syscall_arg__scnprintf_strarray(char *bf, size_t size,
 
 size_t strarrays__scnprintf(struct strarrays *sas, char *bf, size_t size, const char *intfmt, bool show_prefix, int val)
 {
+       size_t printed;
        int i;
 
        for (i = 0; i < sas->nr_entries; ++i) {
@@ -401,7 +406,10 @@ size_t strarrays__scnprintf(struct strarrays *sas, char *bf, size_t size, const
                }
        }
 
-       return scnprintf(bf, size, intfmt, val);
+       printed = scnprintf(bf, size, intfmt, val);
+       if (show_prefix)
+               printed += scnprintf(bf + printed, size - printed, " /* %s??? */", sas->entries[0]->prefix);
+       return printed;
 }
 
 size_t syscall_arg__scnprintf_strarrays(char *bf, size_t size,