IR: Move MDNode clone() methods from ValueMapper to MDNode, NFC

Now that the clone methods used by `MapMetadata()` don't do any
remapping (and return a temporary), they make more sense as member
functions on `MDNode` (and subclasses).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226541 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/IR/Metadata.h

@@ -722,6 +722,9 @@ public:
   static inline TempMDTuple getTemporary(LLVMContext &Context,
                                          ArrayRef<Metadata *> MDs);
 
+  /// \brief Create a (temporary) clone of this.
+  TempMDNode clone() const;
+
   /// \brief Deallocate a node created by getTemporary.
   ///
   /// The node must not have any users.
@@ -898,6 +901,11 @@ class MDTuple : public MDNode {
   static MDTuple *getImpl(LLVMContext &Context, ArrayRef<Metadata *> MDs,
                           StorageType Storage, bool ShouldCreate = true);
 
+  TempMDTuple cloneImpl() const {
+    return getTemporary(getContext(),
+                        SmallVector<Metadata *, 4>(op_begin(), op_end()));
+  }
+
 public:
   /// \brief Get the hash, if any.
   unsigned getHash() const { return SubclassData32; }
@@ -926,6 +934,9 @@ public:
     return TempMDTuple(getImpl(Context, MDs, Temporary));
   }
 
+  /// \brief Return a (temporary) clone of this.
+  TempMDTuple clone() const { return cloneImpl(); }
+
   static bool classof(const Metadata *MD) {
     return MD->getMetadataID() == MDTupleKind;
   }
@@ -965,6 +976,11 @@ class MDLocation : public MDNode {
                              Metadata *InlinedAt, StorageType Storage,
                              bool ShouldCreate = true);
 
+  TempMDLocation cloneImpl() const {
+    return getTemporary(getContext(), getLine(), getColumn(), getScope(),
+                        getInlinedAt());
+  }
+
   // Disallow replacing operands.
   void replaceOperandWith(unsigned I, Metadata *New) LLVM_DELETED_FUNCTION;
 
@@ -991,6 +1007,9 @@ public:
         getImpl(Context, Line, Column, Scope, InlinedAt, Temporary));
   }
 
+  /// \brief Return a (temporary) clone of this.
+  TempMDLocation clone() const { return cloneImpl(); }
+
   unsigned getLine() const { return SubclassData32; }
   unsigned getColumn() const { return SubclassData16; }
   Metadata *getScope() const { return getOperand(0); }
@@ -1054,6 +1073,12 @@ class GenericDwarfNode : public DwarfNode {
                                    StorageType Storage,
                                    bool ShouldCreate = true);
 
+  TempGenericDwarfNode cloneImpl() const {
+    return getTemporary(
+        getContext(), getTag(), getHeader(),
+        SmallVector<Metadata *, 4>(dwarf_op_begin(), dwarf_op_end()));
+  }
+
 public:
   unsigned getHash() const { return SubclassData32; }
 
@@ -1081,6 +1106,9 @@ public:
         getImpl(Context, Tag, Header, DwarfOps, Temporary));
   }
 
+  /// \brief Return a (temporary) clone of this.
+  TempGenericDwarfNode clone() const { return cloneImpl(); }
+
   unsigned getTag() const { return SubclassData16; }
   MDString *getHeader() const { return cast_or_null<MDString>(getOperand(0)); }