[PATCH v2 02/11] perf dwarf-aux: Preserve typedefs in match_var_offset

[Zecheng Li]

From: Zecheng Li <zecheng@xxxxxxxxxx>

Preserve typedefs in match_var_offset to match the results by
__die_get_real_type. Also move the (offset == 0) branch after the
is_pointer check to ensure the correct type is used, fixing cases where
an incorrect pointer type was chosen when the access offset was 0.

Signed-off-by: Zecheng Li <zecheng@xxxxxxxxxx>
Signed-off-by: Zecheng Li <zli94@xxxxxxxx>
---
 tools/perf/util/dwarf-aux.c | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 38142062d6e5..3b0fc9038f19 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -1405,6 +1405,8 @@ struct find_var_data {
 	Dwarf_Addr addr;
 	/* Target register */
 	unsigned reg;
+	/* Access data type */
+	Dwarf_Die type;
 	/* Access offset, set for global data */
 	int offset;
 	/* True if the current register is the frame base */
@@ -1417,29 +1419,31 @@ struct find_var_data {
 static bool match_var_offset(Dwarf_Die *die_mem, struct find_var_data *data,
 			     s64 addr_offset, s64 addr_type, bool is_pointer)
 {
-	Dwarf_Die type_die;
 	Dwarf_Word size;
+	Dwarf_Die ptr_die;
+	Dwarf_Die *ptr_type;
 	s64 offset = addr_offset - addr_type;
 
-	if (offset == 0) {
-		/* Update offset relative to the start of the variable */
-		data->offset = 0;
-		return true;
-	}
-
 	if (offset < 0)
 		return false;
 
-	if (die_get_real_type(die_mem, &type_die) == NULL)
+	if (__die_get_real_type(die_mem, &data->type) == NULL)
 		return false;
 
-	if (is_pointer && dwarf_tag(&type_die) == DW_TAG_pointer_type) {
+	ptr_type = die_get_pointer_type(&data->type, &ptr_die);
+	if (is_pointer && ptr_type) {
 		/* Get the target type of the pointer */
-		if (die_get_real_type(&type_die, &type_die) == NULL)
+		if (__die_get_real_type(ptr_type, &data->type) == NULL)
 			return false;
 	}
 
-	if (dwarf_aggregate_size(&type_die, &size) < 0)
+	if (offset == 0) {
+		/* Update offset relative to the start of the variable */
+		data->offset = 0;
+		return true;
+	}
+
+	if (dwarf_aggregate_size(&data->type, &size) < 0)
 		return false;
 
 	if ((u64)offset >= size)
-- 
2.53.0