[turbofan] Make Node::set_op safer via wrapper.

src/compiler/node-properties.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/operator-properties.h"
 
 namespace v8 {
@@ skipping 178 matching lines @@
       edge.UpdateTo(effect);
     } else {
       DCHECK_NOT_NULL(value);
       edge.UpdateTo(value);
     }
   }
 }
 
 
 // static
+void NodeProperties::ChangeOp(Node* node, const Operator* new_op) {
+  DCHECK_EQ(OperatorProperties::GetTotalInputCount(new_op), node->InputCount());
+  node->set_op(new_op);
+}
+
+
+// static
 Node* NodeProperties::FindProjection(Node* node, size_t projection_index) {
   for (auto use : node->uses()) {
     if (use->opcode() == IrOpcode::kProjection &&
         ProjectionIndexOf(use->op()) == projection_index) {
       return use;
     }
   }
   return nullptr;
 }
 
@@ skipping 64 matching lines @@
 // static
 bool NodeProperties::IsInputRange(Edge edge, int first, int num) {
   if (num == 0) return false;
   int const index = edge.index();
   return first <= index && index < first + num;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8