Missing info in dSYM files when using Swift JSON Decoder with Codable

In a dSYM file created with Xcode 12.4 or Xcode 12.5 beta 3, it seems that there is no info to link structures that use Codable. Or maybe I missed something? I reported the radar FB9035396 with these info.

Steps to Reproduce:

  1. Create a codable Swift structure MyMainStruct with a member variable of type MySubStruct initialized by decoding JSON:
struct MyMainStruct: Codable {
	let subStruct: MySubStruct?

	enum CodingKeys: String, CodingKey {
		case subStruct = "subStruct"

	init(from decoder: Decoder) throws {
		let values = try decoder.container(keyedBy: CodingKeys.self)
		subStruct = try values.decodeIfPresent(MySubStruct.self, forKey: .subStruct)
  1. Archive the project to generate a dSYM file.
  2. Run dwarfdump SimpleSwiftApp.app.dSYM/Contents/Resources/DWARF/SimpleSwiftApp

Result: You can find the declaration of both structures MyMainStruct and MySubStruct:

0x00047f16:     DW_TAG_structure_type
                  DW_AT_name	("MyMainStruct")
                  DW_AT_linkage_name	("$s14SimpleSwiftApp12MyMainStructVD")
                  DW_AT_byte_size	(0x10)
                  DW_AT_APPLE_runtime_class	(DW_LANG_Swift)


0x00048088:     DW_TAG_structure_type
                  DW_AT_name	("MySubStruct")
                  DW_AT_linkage_name	("$s14SimpleSwiftApp11MySubStructVD")
                  DW_AT_byte_size	(0x10)
                  DW_AT_APPLE_runtime_class	(DW_LANG_Swift)

It appears however that there are no link between both structures. I would love to know from the dSYM file that MyMainStruct uses the MySubStruct structure. Maybe the dSYM file should contain a dwarf::DW_TAG_member attribute?

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