Include multiplication in the megamorphic cache hash to avoid cid ranges overlapping modulo table s…

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 14717 matching lines @@
   }
 }
 
 
 void MegamorphicCache::Insert(const Smi& class_id,
                               const Function& target) const {
   ASSERT(static_cast<double>(filled_entry_count() + 1) <=
          (kLoadFactor * static_cast<double>(mask() + 1)));
   const Array& backing_array = Array::Handle(buckets());
   intptr_t id_mask = mask();
-  intptr_t index = class_id.Value() & id_mask;
+  intptr_t index = (class_id.Value() * kSpreadFactor) & id_mask;
   intptr_t i = index;
   do {
     if (Smi::Value(Smi::RawCast(GetClassId(backing_array, i))) == kIllegalCid) {
       SetEntry(backing_array, i, class_id, target);
       set_filled_entry_count(filled_entry_count() + 1);
       return;
     }
     i = (i + 1) & id_mask;
   } while (i != index);
   UNREACHABLE();
@@ skipping 7861 matching lines @@
   return UserTag::null();
 }
 
 
 const char* UserTag::ToCString() const {
   const String& tag_label = String::Handle(label());
   return tag_label.ToCString();
 }
 
 }  // namespace dart