diff --git a/lldb/include/lldb/Expression/Expression.h b/lldb/include/lldb/Expression/Expression.h
--- a/lldb/include/lldb/Expression/Expression.h
+++ b/lldb/include/lldb/Expression/Expression.h
@@ -64,6 +64,10 @@
   /// default, return eLanguageTypeUnknown.
   virtual lldb::LanguageType Language() { return lldb::eLanguageTypeUnknown; }
 
+  /// Return the Materializer that the parser should use when registering
+  /// external values.
+  virtual Materializer *GetMaterializer() { return nullptr; }
+
   /// Return the desired result type of the function, or eResultTypeAny if
   /// indifferent.
   virtual ResultType DesiredResultType() { return eResultTypeAny; }
diff --git a/lldb/include/lldb/Expression/LLVMUserExpression.h b/lldb/include/lldb/Expression/LLVMUserExpression.h
--- a/lldb/include/lldb/Expression/LLVMUserExpression.h
+++ b/lldb/include/lldb/Expression/LLVMUserExpression.h
@@ -63,6 +63,8 @@
 
   bool CanInterpret() override { return m_can_interpret; }
 
+  Materializer *GetMaterializer() override { return m_materializer_up.get(); }
+
   /// Return the string that the parser should parse.  Must be a full
   /// translation unit.
   const char *Text() override { return m_transformed_text.c_str(); }
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp
@@ -576,7 +576,7 @@
 
   auto on_exit = llvm::make_scope_exit([this]() { ResetDeclMap(); });
 
-  if (!DeclMap()->WillParse(exe_ctx, m_materializer_up.get())) {
+  if (!DeclMap()->WillParse(exe_ctx, GetMaterializer())) {
     diagnostic_manager.PutString(
         eDiagnosticSeverityError,
         "current process state is unsuitable for expression parsing");
@@ -764,7 +764,7 @@
 
   auto on_exit = llvm::make_scope_exit([this]() { ResetDeclMap(); });
 
-  if (!DeclMap()->WillParse(exe_ctx, m_materializer_up.get())) {
+  if (!DeclMap()->WillParse(exe_ctx, GetMaterializer())) {
     diagnostic_manager.PutString(
         eDiagnosticSeverityError,
         "current process state is unsuitable for expression parsing");