Don't use ConsStringIterator to compute string hashes

src/objects.cc

 // Copyright 2013 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 <sstream>
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/allocation-site-scopes.h"
@@ skipping 9265 matching lines @@
       if (is_index) is_index = hasher.UpdateIndex(c);
     }
   }
   *utf16_length_out = static_cast<int>(utf16_length);
   // Must set length here so that hash computation is correct.
   hasher.length_ = utf16_length;
   return hasher.GetHashField();
 }
 
 
+void IteratingStringHasher::VisitConsString(ConsString* cons_string) {
+  int length = cons_string->length();
+  uint16_t* buffer = cons_string->GetIsolate()->cons_string_hashing_buffer();
+  if (cons_string->HasOnlyOneByteChars()) {
+    uint8_t* one_byte_buffer = reinterpret_cast<uint8_t*>(buffer);
+    String::WriteToFlat(cons_string, one_byte_buffer, 0, length);

[Yang, 2014/11/26 10:46:15]

Wouldn't this cause OOB writes for large strings? I think what you want is
Min(length, String::kMaxHashCalcLength).

+    AddCharacters(one_byte_buffer, length);
+  } else {
+    String::WriteToFlat(cons_string, buffer, 0, length);
+    AddCharacters(buffer, length);
+  }
+}
+
+
 void String::PrintOn(FILE* file) {
   int length = this->length();
   for (int i = 0; i < length; i++) {
     PrintF(file, "%c", Get(i));
   }
 }
 
 
 inline static uint32_t ObjectAddressForHashing(Object* object) {
   uint32_t value = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(object));
@@ skipping 7512 matching lines @@
   Handle<DependentCode> codes =
       DependentCode::Insert(handle(cell->dependent_code(), info->isolate()),
                             DependentCode::kPropertyCellChangedGroup,
                             info->object_wrapper());
   if (*codes != cell->dependent_code()) cell->set_dependent_code(*codes);
   info->dependencies(DependentCode::kPropertyCellChangedGroup)->Add(
       cell, info->zone());
 }
 
 } }  // namespace v8::internal