[dsymutil] Fix parallel linker's self-recursive typedef DIE by including referred-to types into synthetic name

llvm/lib/DWARFLinker/Parallel/SyntheticTypeNameBuilder.cpp

@@ -377,8 +377,10 @@ Error SyntheticTypeNameBuilder::addTypeName(UnitEntryPairTy InputUnitEntryPair,
   } break;
   }
 
-  // If name for the DIE is not determined yet add referenced types to the name.
-  if (!HasLinkageName && !HasShortName && !HasDeclFileName) {
+  // If name for the DIE is not determined yet or if the DIE is a typedef, add
+  // referenced types to the name.
+  if ((!HasLinkageName && !HasShortName && !HasDeclFileName) ||
+      InputUnitEntryPair.DieEntry->getTag() == dwarf::DW_TAG_typedef) {
     if (InputUnitEntryPair.CU->find(InputUnitEntryPair.DieEntry,
                                     getODRAttributes()))
       if (Error Err = addReferencedODRDies(InputUnitEntryPair, AddParentNames,

llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/odr-fwd-declaration.test

@@ -35,14 +35,14 @@ void foo() { Sptrptr ptr1 = 0; }
 // CHECK: DW_TAG_member
 // CHECK-NEXT: DW_AT_name{{.*}}"field"
 
-// CHECK: 0x[[TYPEDEF_PTR_S]]: DW_TAG_typedef
-// CHECK-NEXT: DW_AT_type{{.*}}{0x[[PTR_S]]} "S *"
-// CHECK-NEXT: DW_AT_name{{.*}}"Sptr"
-
 // CHECK: 0x[[TYPEDEF_PTR_PTR_S:[a-f0-9]*]]: DW_TAG_typedef
 // CHECK-NEXT: DW_AT_type{{.*}}{0x[[PTR_PTR_S]]} "Sptr *"
 // CHECK-NEXT: DW_AT_name{{.*}}"Sptrptr"
 
+// CHECK: 0x[[TYPEDEF_PTR_S]]: DW_TAG_typedef
+// CHECK-NEXT: DW_AT_type{{.*}}{0x[[PTR_S]]} "S *"
+// CHECK-NEXT: DW_AT_name{{.*}}"Sptr"
+
 // First we confirm that first compile unit properly references type.
 //
 // CHECK: DW_TAG_compile_unit

llvm/test/tools/dsymutil/typedefs-with-same-name.test

@@ -0,0 +1,41 @@
+#RUN: dsymutil --linker=parallel -f -oso-prepend-path=%p/Inputs/ -y %s -o %t.dwarf
+#RUN: llvm-dwarfdump %t.dwarf | FileCheck %s
+
+# There should be two typedef DIE named "BarInt" in the resultant .dwarf file.
+# The second should refer to the first, which refer to "Foo<int>".
+# CHECK:      0x[[FIRST_BARINT_ADDR:[0-9a-f]*]]:  DW_TAG_typedef
+# CHECK-NEXT:     DW_AT_type  (0x{{([[:xdigit:]]*)}} "Foo<int>")
+# CHECK-NEXT:     DW_AT_name  ("BarInt")
+# CHECK:      0x{{([[:xdigit:]]*)}}:  DW_TAG_typedef
+# CHECK-NEXT:     DW_AT_type  (0x[[FIRST_BARINT_ADDR]] "BarInt")
+# CHECK-NEXT:     DW_AT_name  ("BarInt")
+
+# Source:
+#
+#   template <typename T> struct Foo;
+#   typedef Foo<int> BarInt;
+#   template <typename T>
+#   struct [[clang::preferred_name(BarInt)]] Foo{};
+#   int main() {
+#     BarInt barInt;
+#     return 0;
+#   }
+#
+# Compile with:
+#
+#   $ clang++ -g -O0 -c typedefs-with-same-name.cpp -o typedefs-with-same-name.o
+#
+# To generate the debug map:
+#
+#   $ clang++ typedefs-with-same-name.o -o typedefs-with-same-name
+#   $ dsymutil -dump-debug-map typedefs-with-same-name
+
+---
+triple:          'arm64-apple-darwin'
+objects:
+  - filename:        '/typedefs-with-same-name.o'
+    timestamp:       1762438746
+    type:            102
+    symbols:
+      - { sym: _main, objAddr: 0x0, binAddr: 0x100000360, size: 0x14 }
+...