Fix a potential overflow of binary search

src/list-inl.h

 // Copyright 2006-2009 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_LIST_INL_H_
 #define V8_LIST_INL_H_
 
 #include "src/list.h"
 
 #include "src/base/macros.h"
@@ skipping 232 matching lines @@
 void List<T, P>::StableSort() {
   ToVector().StableSort();
 }
 
 
 template <typename T, typename P>
 int SortedListBSearch(const List<T>& list, P cmp) {
   int low = 0;
   int high = list.length() - 1;
   while (low <= high) {
-    int mid = (low + high) / 2;
+    int mid = low + (high - low) / 2;
     T mid_elem = list[mid];
 
     if (cmp(&mid_elem) > 0) {
       high = mid - 1;
       continue;
     }
     if (cmp(&mid_elem) < 0) {
       low = mid + 1;
       continue;
     }
@@ skipping 18 matching lines @@
 
 template <typename T>
 int SortedListBSearch(const List<T>& list, T elem) {
   return SortedListBSearch<T, ElementCmp<T> > (list, ElementCmp<T>(elem));
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_LIST_INL_H_