Reland of [interpreter] Add string type feedback to add

src/type-feedback-vector-inl.h

 // Copyright 2012 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.
 
 #ifndef V8_TYPE_FEEDBACK_VECTOR_INL_H_
 #define V8_TYPE_FEEDBACK_VECTOR_INL_H_
 
 #include "src/globals.h"
 #include "src/type-feedback-vector.h"
 
@@ skipping 111 matching lines @@
 
 // Helper function to transform the feedback to BinaryOperationHint.
 BinaryOperationHint BinaryOperationHintFromFeedback(int type_feedback) {
   switch (type_feedback) {
     case BinaryOperationFeedback::kNone:
       return BinaryOperationHint::kNone;
     case BinaryOperationFeedback::kSignedSmall:
       return BinaryOperationHint::kSignedSmall;
     case BinaryOperationFeedback::kNumber:
       return BinaryOperationHint::kNumberOrOddball;
+    case BinaryOperationFeedback::kString:
+      return BinaryOperationHint::kString;
     case BinaryOperationFeedback::kAny:
     default:
       return BinaryOperationHint::kAny;
   }
   UNREACHABLE();
   return BinaryOperationHint::kNone;
 }
 
 // Helper function to transform the feedback to CompareOperationHint.
 CompareOperationHint CompareOperationHintFromFeedback(int type_feedback) {
@@ skipping 134 matching lines @@
   int index = vector()->GetIndex(slot()) + 1;
   vector()->set(index, feedback_extra, mode);
 }
 
 
 Isolate* FeedbackNexus::GetIsolate() const { return vector()->GetIsolate(); }
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TYPE_FEEDBACK_VECTOR_INL_H_