diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCClassDescriptorV2.cpp b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCClassDescriptorV2.cpp
index 39969520b7455..54c9f328b5b78 100644
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCClassDescriptorV2.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCClassDescriptorV2.cpp
@@ -394,7 +394,7 @@ bool ClassDescriptorV2::relative_list_entry_t::Read(Process *process,
   lldb::offset_t cursor = 0;
   uint64_t raw_entry = extractor.GetU64_unchecked(&cursor);
   m_image_index = raw_entry & 0xFFFF;
-  m_list_offset = (int64_t)(raw_entry >> 16);
+  m_list_offset = llvm::SignExtend64<48>(raw_entry >> 16);
   return true;
 }