[clang-diff] Remove NodeCountVisitor, NFC

lib/Tooling/ASTDiff/ASTDiff.cpp

public:
   template <class T>
   Impl(SyntaxTree *Parent,
        typename std::enable_if<std::is_base_of<Decl, T>::value, T>::type *Node,
        ASTUnit &AST)
       : Impl(Parent, dyn_cast<Decl>(Node), AST) {}
 
   SyntaxTree *Parent;
   ASTUnit &AST;
+  /// Nodes in preorder.
+  std::vector<Node> Nodes;
   std::vector<NodeId> Leaves;
   // Maps preorder indices to postorder ones.
   std::vector<int> PostorderIds;
   std::vector<NodeId> NodesBfs;
 
   int getSize() const { return Nodes.size(); }
   NodeId getRootId() const { return 0; }
   PreorderIterator begin() const { return getRootId(); }
public:
   std::string getRelativeName(const NamedDecl *ND) const;
 
   std::string getNodeValue(NodeId Id) const;
   std::string getNodeValue(const Node &Node) const;
   std::string getDeclValue(const Decl *D) const;
   std::string getStmtValue(const Stmt *S) const;
 
 private:
-  /// Nodes in preorder.
-  std::vector<Node> Nodes;
-
   void initTree();
   void setLeftMostDescendants();
 };
 
 static bool isSpecializedNodeExcluded(const Decl *D) { return D->isImplicit(); }
 static bool isSpecializedNodeExcluded(const Stmt *S) { return false; }
 
 template <class T> static bool isNodeExcluded(ASTUnit &AST, T *N) {
static SourceRange getSourceRange(const ASTUnit &AST, const DynTypedNode &DTN) {
   if (auto *ThisExpr = DTN.get<CXXThisExpr>()) {
     if (ThisExpr->isImplicit())
       EndLoc = BeginLoc;
   }
   return {SrcMgr.getExpansionLoc(BeginLoc), SrcMgr.getExpansionLoc(EndLoc)};
 }
 
 namespace {
-/// Counts the number of nodes that will be compared.
-struct NodeCountVisitor : public RecursiveASTVisitor<NodeCountVisitor> {
-  int Count = 0;
-  const SyntaxTree::Impl &Tree;
-  NodeCountVisitor(const SyntaxTree::Impl &Tree) : Tree(Tree) {}
-  bool TraverseDecl(Decl *D) {
-    if (isNodeExcluded(Tree.AST, D))
-      return true;
-    ++Count;
-    RecursiveASTVisitor<NodeCountVisitor>::TraverseDecl(D);
-    return true;
-  }
-  bool TraverseStmt(Stmt *S) {
-    if (S)
-      S = S->IgnoreImplicit();
-    if (isNodeExcluded(Tree.AST, S))
-      return true;
-    ++Count;
-    RecursiveASTVisitor<NodeCountVisitor>::TraverseStmt(S);
-    return true;
-  }
-  bool TraverseType(QualType T) { return true; }
-};
-} // end anonymous namespace
-
-namespace {
 // Sets Height, Parent and Children for each node.
 struct PreorderVisitor : public RecursiveASTVisitor<PreorderVisitor> {
   int Id = 0, Depth = 0;
   NodeId Parent;
   SyntaxTree::Impl &Tree;
 
   PreorderVisitor(SyntaxTree::Impl &Tree) : Tree(Tree) {}
 
   template <class T> std::tuple<NodeId, NodeId> PreTraverse(T *ASTNode) {
     NodeId MyId = Id;
+    Tree.Nodes.emplace_back();
     Node &N = Tree.getMutableNode(MyId);
     N.Parent = Parent;
     N.Depth = Depth;
     N.ASTNode = DynTypedNode::create(*ASTNode);
     assert(!N.ASTNode.getNodeKind().isNone() &&
            "Expected nodes to have a valid kind.");
     if (Parent.isValid()) {
       Node &P = Tree.getMutableNode(Parent);
bool TraverseStmt(Stmt *S) {
     return true;
   }
   bool TraverseType(QualType T) { return true; }
 };
 } // end anonymous namespace
 
 SyntaxTree::Impl::Impl(SyntaxTree *Parent, Decl *N, ASTUnit &AST)
     : Parent(Parent), AST(AST) {
-  NodeCountVisitor NodeCounter(*this);
-  NodeCounter.TraverseDecl(N);
-  Nodes.resize(NodeCounter.Count);
   PreorderVisitor PreorderWalker(*this);
   PreorderWalker.TraverseDecl(N);
   initTree();
 }
 
 SyntaxTree::Impl::Impl(SyntaxTree *Parent, Stmt *N, ASTUnit &AST)
     : Parent(Parent), AST(AST) {
-  NodeCountVisitor NodeCounter(*this);
-  NodeCounter.TraverseStmt(N);
-  Nodes.resize(NodeCounter.Count);
   PreorderVisitor PreorderWalker(*this);
   PreorderWalker.TraverseStmt(N);
   initTree();
 }
 
 static std::vector<NodeId> getSubtreePostorder(const SyntaxTree::Impl &Tree,
                                                NodeId Root) {
   std::vector<NodeId> Postorder;