perf dwarf-aux: Handle array types in die_get_member_type

When a struct member is an array type, die_get_member_type() would stop
iterating since array types weren't handled in the loop. This caused
accesses to array elements within structs to not resolve properly.

Add array type handling by resolving the array to its element type and
calculating the offset within an element using modulo arithmetic

This improves type annotation coverage for struct members that are
arrays.

Signed-off-by: Zecheng Li <zli94@ncsu.edu>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 1484aa7568262dfea667193a8da1d833d422e629..1feefc329154fe8a7d89782340d1e905d0760b24 100644 (file)
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -2127,13 +2127,28 @@ Dwarf_Die *die_get_member_type(Dwarf_Die *type_die, int offset,
 
                tag = dwarf_tag(&mb_type);
 
-               if (tag == DW_TAG_structure_type || tag == DW_TAG_union_type) {
+               if (tag == DW_TAG_structure_type || tag == DW_TAG_union_type ||
+                   tag == DW_TAG_array_type) {
                        Dwarf_Word loc;
 
                        /* Update offset for the start of the member struct */
                        if (die_get_data_member_location(member, &loc) == 0)
                                offset -= loc;
                }
+
+               /* Handle array types: resolve to the element type by one level */
+               if (tag == DW_TAG_array_type) {
+                       Dwarf_Word size;
+
+                       if (die_get_real_type(&mb_type, &mb_type) == NULL)
+                               return NULL;
+
+                       if (dwarf_aggregate_size(&mb_type, &size) < 0)
+                               return NULL;
+
+                       offset = offset % size;
+                       tag = dwarf_tag(&mb_type);
+               }
        }
        *die_mem = mb_type;
        return die_mem;