[lldb/DWARF] Resolve type unit references in llvm DWARFDIE compatibility wrappers

The llvm versions of these functions do that, so we must to so as well.
Practically this meant that were were unable to correctly un-simplify
the names of some types when using type units, which resulted in type
lookup errors.

Author: labath

lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp

@@ -622,12 +622,12 @@ std::optional<uint64_t> DWARFDIE::getLanguage() const {
 }
 
 DWARFDIE DWARFDIE::resolveReferencedType(dw_attr_t attr) const {
-  return GetReferencedDIE(attr);
+  return GetReferencedDIE(attr).resolveTypeUnitReference();
 }
 
 DWARFDIE DWARFDIE::resolveReferencedType(DWARFFormValue v) const {
   if (IsValid())
-    return v.Reference();
+    return v.Reference().resolveTypeUnitReference();
   return {};
 }
 

lldb/test/Shell/SymbolFile/DWARF/x86/simplified-template-names.cpp

@@ -11,12 +11,23 @@
 // Test that we following DW_AT_signature correctly. If not, lldb might confuse the types of v1 and v2.
 // RUN: %clangxx --target=x86_64-pc-linux -g -gsimple-template-names -fdebug-types-section %s -c -o %t2.o
 // RUN: ld.lld %t2.o -o %t2
-// RUN: %lldb %t2 -o "target variable v1 v2" -o exit | FileCheck %s --check-prefix=TYPE
+// RUN: %lldb %t2 -o "target variable v1 v2" \
+// RUN:   -o "type lookup t2<outer_struct1>" -o "type lookup t2<outer_struct2>" \
+// RUN:   -o exit | FileCheck %s --check-prefix=TYPE
 
 // LOG: unique name: t3<t2<int> >::t4
 
-// TYPE:      (t2<outer_struct1::t1<int> >) v1 = {}
-// TYPE-NEXT: (t2<outer_struct2::t1<int> >) v2 = {}
+// TYPE-LABEL: target variable v1 v2
+// TYPE:       (t2<outer_struct1::t1<int> >) v1 = {}
+// TYPE:       (t2<outer_struct2::t1<int> >) v2 = {}
+
+// TYPE-LABEL: type lookup t2<outer_struct1>
+// TYPE:       template<> struct t2<outer_struct1> {
+// TYPE-NEXT:  }
+
+// TYPE-LABEL: type lookup t2<outer_struct2>
+// TYPE:       template<> struct t2<outer_struct2> {
+// TYPE-NEXT:  }
 
 struct outer_struct1 {
   template <typename> struct t1 {};
@@ -30,6 +41,9 @@ template <typename> struct t2 {};
 t2<outer_struct1::t1<int>> v1;
 t2<outer_struct2::t1<int>> v2;
 
+t2<outer_struct1> v1_1;
+t2<outer_struct2> v1_2;
+
 template <typename> struct t3 {
   struct t4 {};
 };