ARM microoptimizations to megamorphic stub probing.

src/stub-cache.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 325 matching lines @@
   // we do in generated code.  We generate an hash code that already
   // ends in String::kHashShift 0s.  Then we shift it so it is a multiple
   // of sizeof(Entry).  This makes it easier to avoid making mistakes
   // in the hashed offset computations.
   static Entry* entry(Entry* table, int offset) {
     const int shift_amount = kPointerSizeLog2 + 1 - String::kHashShift;
     return reinterpret_cast<Entry*>(
         reinterpret_cast<Address>(table) + (offset << shift_amount));
   }
 
-  static const int kPrimaryTableSize = 2048;
-  static const int kSecondaryTableSize = 512;
+  static const int kPrimaryTableBits = 11;
+  static const int kPrimaryTableSize = (1 << kPrimaryTableBits);
+  static const int kSecondaryTableBits = 9;
+  static const int kSecondaryTableSize = (1 << kSecondaryTableBits);
 
   Entry primary_[kPrimaryTableSize];
   Entry secondary_[kSecondaryTableSize];
   Isolate* isolate_;
 
   friend class Isolate;
   friend class SCTableReference;
 
   DISALLOW_COPY_AND_ASSIGN(StubCache);
 };
@@ skipping 500 matching lines @@
   Handle<JSFunction> constant_function_;
   bool is_simple_api_call_;
   Handle<FunctionTemplateInfo> expected_receiver_type_;
   Handle<CallHandlerInfo> api_call_info_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_STUB_CACHE_H_