perf annotate-data: Prefer struct/union over base type

Sometimes a compound type can have a single field and the size is the
same as the base type.  But it's still preferred as struct or union
could carry more information than the base type.

Also put a slight priority on the typedef for the same reason.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240821065408.285548-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 19 insertions, 1 deletions

diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c
index e5589268cb42..bc65264084d8 100644
--- a/tools/perf/util/annotate-data.c
+++ b/tools/perf/util/annotate-data.c
@@ -404,6 +404,13 @@ static bool is_pointer_type(Dwarf_Die *type_die)
 	return tag == DW_TAG_pointer_type || tag == DW_TAG_array_type;
 }
 
+static bool is_compound_type(Dwarf_Die *type_die)
+{
+	int tag = dwarf_tag(type_die);
+
+	return tag == DW_TAG_structure_type || tag == DW_TAG_union_type;
+}
+
 /* returns if Type B has better information than Type A */
 static bool is_better_type(Dwarf_Die *type_a, Dwarf_Die *type_b)
 {
@@ -433,7 +440,18 @@ static bool is_better_type(Dwarf_Die *type_a, Dwarf_Die *type_b)
 	    dwarf_aggregate_size(type_b, &size_b) < 0)
 		return false;
 
-	return size_a < size_b;
+	if (size_a != size_b)
+		return size_a < size_b;
+
+	/* struct or union is preferred */
+	if (is_compound_type(type_a) != is_compound_type(type_b))
+		return is_compound_type(type_b);
+
+	/* typedef is preferred */
+	if (dwarf_tag(type_b) == DW_TAG_typedef)
+		return true;
+
+	return false;
 }
 
 /* The type info will be saved in @type_die */