Fix -Wdeprecated regarding ORC copying ValueMaterializers

As usual, this is a polymorphic hierarchy without polymorphic ownership,
so simply make the dtor protected non-virtual, protected default copy
ctor/assign, and make derived classes final. The derived classes will
pick up correct default public copy ops (and dtor) implicitly.

(wish I could add -Wdeprecated to the build, but last time I tried it
triggered on some system headers I still need to look into/figure out)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@250747 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ExecutionEngine/Orc/CompileOnDemandLayer.h

@@ -44,7 +44,7 @@ class CompileOnDemandLayer {
 private:
 
   template <typename MaterializerFtor>
-  class LambdaMaterializer : public ValueMaterializer {
+  class LambdaMaterializer final : public ValueMaterializer {
   public:
     LambdaMaterializer(MaterializerFtor M) : M(std::move(M)) {}
     Value* materializeValueFor(Value *V) final {

include/llvm/Transforms/Utils/ValueMapper.h

@@ -38,9 +38,14 @@ namespace llvm {
   /// to materialize Values on demand.
   class ValueMaterializer {
     virtual void anchor(); // Out of line method.
-  public:
-    virtual ~ValueMaterializer() {}
 
+  protected:
+    ~ValueMaterializer() = default;
+    ValueMaterializer() = default;
+    ValueMaterializer(const ValueMaterializer&) = default;
+    ValueMaterializer &operator=(const ValueMaterializer&) = default;
+
+  public:
     /// materializeValueFor - The client should implement this method if they
     /// want to generate a mapped Value on demand. For example, if linking
     /// lazily.

lib/Linker/LinkModules.cpp

@@ -365,7 +365,7 @@ class ModuleLinker;
 /// Creates prototypes for functions that are lazily linked on the fly. This
 /// speeds up linking for modules with many/ lazily linked functions of which
 /// few get used.
-class ValueMaterializerTy : public ValueMaterializer {
+class ValueMaterializerTy final : public ValueMaterializer {
   TypeMapTy &TypeMap;
   Module *DstM;
   std::vector<GlobalValue *> &LazilyLinkGlobalValues;