TransitionArray::Search() now returns insertion index if the entry was not found.

src/objects-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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 2783 matching lines @@
 
 void DescriptorArray::SetNumberOfDescriptors(int number_of_descriptors) {
   WRITE_FIELD(
       this, kDescriptorLengthOffset, Smi::FromInt(number_of_descriptors));
 }
 
 
 // Perform a binary search in a fixed array. Low and high are entry indices. If
 // there are three entries in this array it should be called with low=0 and
 // high=2.
-template<SearchMode search_mode, typename T>
-int BinarySearch(T* array, Name* name, int low, int high, int valid_entries) {
+template <SearchMode search_mode, typename T>
+int BinarySearch(T* array, Name* name, int low, int high, int valid_entries,
+                 int* out_insertion_index) {
+  DCHECK(search_mode == ALL_ENTRIES || out_insertion_index == NULL);
   uint32_t hash = name->Hash();
   int limit = high;
 
   DCHECK(low <= high);
 
   while (low != high) {
     int mid = (low + high) / 2;
     Name* mid_name = array->GetSortedKey(mid);
     uint32_t mid_hash = mid_name->Hash();
 
     if (mid_hash >= hash) {
       high = mid;
     } else {
       low = mid + 1;
     }
   }
 
   for (; low <= limit; ++low) {
     int sort_index = array->GetSortedKeyIndex(low);
     Name* entry = array->GetKey(sort_index);
-    if (entry->Hash() != hash) break;
+    uint32_t current_hash = entry->Hash();
+    if (current_hash != hash) {
+      if (out_insertion_index != NULL) {
+        *out_insertion_index = sort_index + (current_hash > hash ? 0 : 1);
+      }
+      return T::kNotFound;
+    }
     if (entry->Equals(name)) {
       if (search_mode == ALL_ENTRIES || sort_index < valid_entries) {
         return sort_index;
       }
       return T::kNotFound;
     }
   }
 
+  if (out_insertion_index != NULL) *out_insertion_index = limit + 1;
   return T::kNotFound;
 }
 
 
 // Perform a linear search in this fixed array. len is the number of entry
 // indices that are valid.
-template<SearchMode search_mode, typename T>
-int LinearSearch(T* array, Name* name, int len, int valid_entries) {
+template <SearchMode search_mode, typename T>
+int LinearSearch(T* array, Name* name, int len, int valid_entries,
+                 int* out_insertion_index) {
   uint32_t hash = name->Hash();
   if (search_mode == ALL_ENTRIES) {
     for (int number = 0; number < len; number++) {
       int sorted_index = array->GetSortedKeyIndex(number);
       Name* entry = array->GetKey(sorted_index);
       uint32_t current_hash = entry->Hash();
-      if (current_hash > hash) break;
+      if (current_hash > hash) {
+        if (out_insertion_index != NULL) *out_insertion_index = sorted_index;
+        return T::kNotFound;
+      }
       if (current_hash == hash && entry->Equals(name)) return sorted_index;
     }
+    if (out_insertion_index != NULL) *out_insertion_index = len;
+    return T::kNotFound;
   } else {
     DCHECK(len >= valid_entries);
+    DCHECK_EQ(NULL, out_insertion_index);  // Not supported here.
     for (int number = 0; number < valid_entries; number++) {
       Name* entry = array->GetKey(number);
       uint32_t current_hash = entry->Hash();
       if (current_hash == hash && entry->Equals(name)) return number;
     }
+    return T::kNotFound;
   }
-  return T::kNotFound;
 }
 
 
-template<SearchMode search_mode, typename T>
-int Search(T* array, Name* name, int valid_entries) {
+template <SearchMode search_mode, typename T>
+int Search(T* array, Name* name, int valid_entries, int* out_insertion_index) {
   if (search_mode == VALID_ENTRIES) {
     SLOW_DCHECK(array->IsSortedNoDuplicates(valid_entries));
   } else {
     SLOW_DCHECK(array->IsSortedNoDuplicates());
   }
 
   int nof = array->number_of_entries();
-  if (nof == 0) return T::kNotFound;
+  if (nof == 0) {
+    if (out_insertion_index != NULL) *out_insertion_index = 0;
+    return T::kNotFound;
+  }
 
   // Fast case: do linear search for small arrays.
   const int kMaxElementsForLinearSearch = 8;
   if ((search_mode == ALL_ENTRIES &&
        nof <= kMaxElementsForLinearSearch) ||
       (search_mode == VALID_ENTRIES &&
        valid_entries <= (kMaxElementsForLinearSearch * 3))) {
-    return LinearSearch<search_mode>(array, name, nof, valid_entries);
+    return LinearSearch<search_mode>(array, name, nof, valid_entries,
+                                     out_insertion_index);
   }
 
   // Slow case: perform binary search.
-  return BinarySearch<search_mode>(array, name, 0, nof - 1, valid_entries);
+  return BinarySearch<search_mode>(array, name, 0, nof - 1, valid_entries,
+                                   out_insertion_index);
 }
 
 
 int DescriptorArray::Search(Name* name, int valid_descriptors) {
-  return internal::Search<VALID_ENTRIES>(this, name, valid_descriptors);
+  return internal::Search<VALID_ENTRIES>(this, name, valid_descriptors, NULL);
 }
 
 
 int DescriptorArray::SearchWithCache(Name* name, Map* map) {
   int number_of_own_descriptors = map->NumberOfOwnDescriptors();
   if (number_of_own_descriptors == 0) return kNotFound;
 
   DescriptorLookupCache* cache = GetIsolate()->descriptor_lookup_cache();
   int number = cache->Lookup(map, name);
 
@@ skipping 4394 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_