Add reorder method for RecordDecl

Author: connorkuehl

clang/include/clang/AST/Decl.h

@@ -3814,6 +3814,8 @@ class RecordDecl : public TagDecl {
   /// nullptr is returned if no named data member exists.
   const FieldDecl *findFirstNamedDataMember() const;
 
+  void reorderFields(ArrayRef<Decl *> Decls) const;
+
 private:
   /// Deserialize just the fields.
   void LoadFieldsFromExternalStorage() const;

clang/lib/AST/Decl.cpp

@@ -4148,6 +4148,14 @@ RecordDecl::field_iterator RecordDecl::field_begin() const {
   return field_iterator(decl_iterator(FirstDecl));
 }
 
+void RecordDecl::reorderFields(ArrayRef<Decl *> Decls) const {
+  Decl *NewFirst, *NewLast;
+  std::tie(NewFirst, NewLast) =
+      BuildDeclChain(Decls, false);
+  FirstDecl = NewFirst;
+  LastDecl = NewLast;
+}
+
 /// completeDefinition - Notes that the definition of this type is now
 /// complete.
 void RecordDecl::completeDefinition() {