diff --git a/llvm/include/llvm/Demangle/ItaniumDemangle.h b/llvm/include/llvm/Demangle/ItaniumDemangle.h
--- a/llvm/include/llvm/Demangle/ItaniumDemangle.h
+++ b/llvm/include/llvm/Demangle/ItaniumDemangle.h
@@ -445,6 +445,14 @@
   }
 };
 
+#ifdef _MSC_VER
+// Workaround for MSVC++ bug (Version 2017, 15.8.9) - w/o this forward
+// declaration, the friend declaration in ObjCProtoName below has no effect
+// and leads to compilation error when ObjCProtoName::Protocol private field
+// is accessed in PointerType::printLeft.
+class PointerType;
+#endif // _MSC_VER
+
 class ObjCProtoName : public Node {
   const Node *Ty;
   StringView Protocol;
@@ -1199,7 +1207,7 @@
 
   template<typename Fn> void match(Fn F) const { F(Params); }
 
-  NodeArray getParams() { return Params; }
+  const NodeArray &getParams() const { return Params; }
 
   void printLeft(OutputStream &S) const override {
     S += "<";
@@ -2057,6 +2065,9 @@
     else
       S << Integer;
   }
+
+  // Retrieves the string view of the integer value this node represents.
+  const StringView &getIntegerValue() const { return Integer; }
 };
 
 class IntegerLiteral : public Node {
@@ -2085,6 +2096,13 @@
     if (Type.size() <= 3)
       S += Type;
   }
+
+  // Retrieves the string view of the integer value represented by this node.
+  const StringView &getValue() const { return Value; }
+
+  // Retrieves the string view of the type string of the integer value this node
+  // represents.
+  const StringView &getType() const { return Type; }
 };
 
 template <class Float> struct FloatData;