Index: source/Plugins/SymbolFile/DWARF/DIERef.h
===================================================================
--- source/Plugins/SymbolFile/DWARF/DIERef.h
+++ source/Plugins/SymbolFile/DWARF/DIERef.h
@@ -25,10 +25,6 @@
 
   explicit DIERef(const DWARFFormValue &form_value);
 
-  bool operator<(const DIERef &ref) const {
-    return die_offset < ref.die_offset;
-  }
-
   explicit operator bool() const {
     return cu_offset != DW_INVALID_OFFSET || die_offset != DW_INVALID_OFFSET;
   }
Index: source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
===================================================================
--- source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
+++ source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
@@ -998,7 +998,7 @@
             clang_type.GetOpaqueQualType();
         dwarf->GetForwardDeclClangTypeToDie()
             [ClangUtil::RemoveFastQualifiers(clang_type).GetOpaqueQualType()] =
-            die.GetDIERef();
+            die.GetID();
         m_ast.SetHasExternalStorage(clang_type.GetOpaqueQualType(), true);
       }
     }
Index: source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
===================================================================
--- source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
+++ source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
@@ -311,7 +311,8 @@
   typedef llvm::DenseMap<const DWARFDebugInfoEntry *,
                          lldb::opaque_compiler_type_t>
       DIEToClangType;
-  typedef llvm::DenseMap<lldb::opaque_compiler_type_t, DIERef> ClangTypeToDIE;
+  typedef llvm::DenseMap<lldb::opaque_compiler_type_t, lldb::user_id_t>
+      ClangTypeToDIE;
 
   struct DWARFDataSegment {
     llvm::once_flag m_flag;
@@ -475,8 +476,8 @@
   bool m_fetched_external_modules : 1;
   lldb_private::LazyBool m_supports_DW_AT_APPLE_objc_complete_type;
 
-  typedef std::shared_ptr<std::set<DIERef>> DIERefSetSP;
-  typedef std::unordered_map<std::string, DIERefSetSP> NameToOffsetMap;
+  typedef std::set<lldb::user_id_t> DIERefSet;
+  typedef llvm::StringMap<DIERefSet> NameToOffsetMap;
   NameToOffsetMap m_function_scope_qualified_name_map;
   std::unique_ptr<DWARFDebugRangesBase> m_ranges;
   std::unique_ptr<DWARFDebugRangesBase> m_rnglists;
Index: source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
===================================================================
--- source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -2341,15 +2341,9 @@
       dwo->GetMangledNamesForFunction(scope_qualified_name, mangled_names);
   }
 
-  NameToOffsetMap::iterator iter =
-      m_function_scope_qualified_name_map.find(scope_qualified_name);
-  if (iter == m_function_scope_qualified_name_map.end())
-    return;
-
-  DIERefSetSP set_sp = (*iter).second;
-  std::set<DIERef>::iterator set_iter;
-  for (set_iter = set_sp->begin(); set_iter != set_sp->end(); set_iter++) {
-    DWARFDIE die = DebugInfo()->GetDIE(*set_iter);
+  for (lldb::user_id_t uid :
+       m_function_scope_qualified_name_map.lookup(scope_qualified_name)) {
+    DWARFDIE die = GetDIE(uid);
     mangled_names.push_back(ConstString(die.GetMangledName()));
   }
 }
@@ -2988,22 +2982,12 @@
             type_list->Insert(type_sp);
 
           if (die.Tag() == DW_TAG_subprogram) {
-            DIERef die_ref = die.GetDIERef();
             std::string scope_qualified_name(GetDeclContextForUID(die.GetID())
                                                  .GetScopeQualifiedName()
                                                  .AsCString(""));
             if (scope_qualified_name.size()) {
-              NameToOffsetMap::iterator iter =
-                  m_function_scope_qualified_name_map.find(
-                      scope_qualified_name);
-              if (iter != m_function_scope_qualified_name_map.end())
-                (*iter).second->insert(die_ref);
-              else {
-                DIERefSetSP new_set(new std::set<DIERef>);
-                new_set->insert(die_ref);
-                m_function_scope_qualified_name_map.emplace(
-                    std::make_pair(scope_qualified_name, new_set));
-              }
+              m_function_scope_qualified_name_map[scope_qualified_name].insert(
+                  die.GetID());
             }
           }
         }