perf probe: Correct error message for non-structure type

perf probe outputs incorrect error message when it is called with
non-existent field on a non-data structure local variable.

<Before>
 # perf probe vfs_read 'count.hoge'
  Fatal: Structure on a register is not supported yet.
 # perf probe vfs_read 'count->hoge'
  Fatal: Semantic error: hoge must be referred by '.'

This corrects the messsage.

<After>
 # perf probe vfs_read 'count.hoge'
  Fatal: count is not a data structure.
 # perf probe vfs_read 'count->hoge'
  Fatal: count is not a data structure.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
LKML-Reference: <20100402165052.23551.75866.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 8 insertions, 4 deletions

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index b44132ead95a..59b0115de30a 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -429,12 +429,20 @@ static void convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
                 if (die_get_real_type(&type, &type) == NULL)
                         die("Failed to get a type information of %s.", varname);
 
+                /* Verify it is a data structure  */
+                if (dwarf_tag(&type) != DW_TAG_structure_type)
+                        die("%s is not a data structure.", varname);
+
                 ref = xzalloc(sizeof(struct kprobe_trace_arg_ref));
                 if (*ref_ptr)
                         (*ref_ptr)->next = ref;
                 else
                         *ref_ptr = ref;
         } else {
+                /* Verify it is a data structure  */
+                if (dwarf_tag(&type) != DW_TAG_structure_type)
+                        die("%s is not a data structure.", varname);
+
                 if (field->ref)
                         die("Semantic error: %s must be referred by '.'",
                             field->name);
@@ -442,10 +450,6 @@ static void convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
                         die("Structure on a register is not supported yet.");
         }
 
-        /* Verify it is a data structure  */
-        if (dwarf_tag(&type) != DW_TAG_structure_type)
-                die("%s is not a data structure.", varname);
-
         if (die_find_member(&type, field->name, &member) == NULL)
                 die("%s(tyep:%s) has no member %s.", varname,
                     dwarf_diename(&type), field->name);