diff --git a/lldb/include/lldb/Target/ProcessStructReader.h b/lldb/include/lldb/Target/ProcessStructReader.h
--- a/lldb/include/lldb/Target/ProcessStructReader.h
+++ b/lldb/include/lldb/Target/ProcessStructReader.h
@@ -14,11 +14,12 @@
 
 #include "lldb/Symbol/CompilerType.h"
 #include "lldb/Target/Process.h"
-#include "lldb/Utility/ConstString.h"
 #include "lldb/Utility/DataBufferHeap.h"
 #include "lldb/Utility/DataExtractor.h"
 #include "lldb/Utility/Status.h"
 
+#include "llvm/ADT/StringMap.h"
+
 #include <initializer_list>
 #include <map>
 #include <string>
@@ -32,7 +33,7 @@
     size_t size;
   };
 
-  std::map<ConstString, FieldImpl> m_fields;
+  llvm::StringMap<FieldImpl> m_fields;
   DataExtractor m_data;
   lldb::ByteOrder m_byte_order;
   size_t m_addr_byte_size;
@@ -62,10 +63,9 @@
       // no support for things larger than a uint64_t (yet)
       if (!size || *size > 8)
         return;
-      ConstString const_name = ConstString(name.c_str());
       size_t byte_index = static_cast<size_t>(bit_offset / 8);
-      m_fields[const_name] =
-          FieldImpl{field_type, byte_index, static_cast<size_t>(*size)};
+      m_fields.insert({name, FieldImpl{field_type, byte_index,
+                                       static_cast<size_t>(*size)}});
     }
     auto total_size = struct_type.GetByteSize(nullptr);
     if (!total_size)
@@ -80,7 +80,7 @@
   }
 
   template <typename RetType>
-  RetType GetField(ConstString name, RetType fail_value = RetType()) {
+  RetType GetField(llvm::StringRef name, RetType fail_value = RetType()) {
     auto iter = m_fields.find(name), end = m_fields.end();
     if (iter == end)
       return fail_value;
diff --git a/lldb/source/Plugins/SystemRuntime/MacOSX/SystemRuntimeMacOSX.cpp b/lldb/source/Plugins/SystemRuntime/MacOSX/SystemRuntimeMacOSX.cpp
--- a/lldb/source/Plugins/SystemRuntime/MacOSX/SystemRuntimeMacOSX.cpp
+++ b/lldb/source/Plugins/SystemRuntime/MacOSX/SystemRuntimeMacOSX.cpp
@@ -442,13 +442,13 @@
                                         dispatch_tsd_indexes_s);
 
       m_libdispatch_tsd_indexes.dti_version =
-          struct_reader.GetField<uint16_t>(ConstString("dti_version"));
+          struct_reader.GetField<uint16_t>("dti_version");
       m_libdispatch_tsd_indexes.dti_queue_index =
-          struct_reader.GetField<uint16_t>(ConstString("dti_queue_index"));
+          struct_reader.GetField<uint16_t>("dti_queue_index");
       m_libdispatch_tsd_indexes.dti_voucher_index =
-          struct_reader.GetField<uint16_t>(ConstString("dti_voucher_index"));
+          struct_reader.GetField<uint16_t>("dti_voucher_index");
       m_libdispatch_tsd_indexes.dti_qos_class_index =
-          struct_reader.GetField<uint16_t>(ConstString("dti_qos_class_index"));
+          struct_reader.GetField<uint16_t>("dti_qos_class_index");
     }
   }
 }