Introduce new Value class design, inspired by APValue

Author: SahilPatidar

clang/include/clang/Interpreter/Interpreter.h

@@ -182,7 +182,7 @@ class Interpreter {
 
   llvm::Expected<PartialTranslationUnit &> Parse(llvm::StringRef Code);
   llvm::Error Execute(PartialTranslationUnit &T);
-  llvm::Error ParseAndExecute(llvm::StringRef Code);
+  llvm::Error ParseAndExecute(llvm::StringRef Code, Value *V = nullptr);
 
   /// Undo N previous incremental inputs.
   llvm::Error Undo(unsigned N = 1);