Inline instance object hash code into object header on 64 bit.

runtime/vm/raw_object.h

 // 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.
 
 #ifndef RUNTIME_VM_RAW_OBJECT_H_
 #define RUNTIME_VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/atomic.h"
 #include "vm/exceptions.h"
@@ skipping 253 matching lines @@
     kMarkBit = 0,
     kCanonicalBit = 1,
     kVMHeapObjectBit = 2,
     kRememberedBit = 3,
     kReservedTagPos = 4,  // kReservedBit{100K,1M,10M}
     kReservedTagSize = 4,
     kSizeTagPos = kReservedTagPos + kReservedTagSize,  // = 8
     kSizeTagSize = 8,
     kClassIdTagPos = kSizeTagPos + kSizeTagSize,  // = 16
     kClassIdTagSize = 16,
+#if defined(HASH_IN_OBJECT_HEADER)
+    kHashTagPos = kClassIdTagPos + kClassIdTagSize,  // = 32
+    kHashTagSize = 16,
+#endif
   };
 
   COMPILE_ASSERT(kClassIdTagSize == (sizeof(classid_t) * kBitsPerByte));
 
   // Encodes the object size in the tag in units of object alignment.
   class SizeTag {
    public:
     static const intptr_t kMaxSizeTag = ((1 << RawObject::kSizeTagSize) - 1)
                                         << kObjectAlignmentLog2;
 
@@ skipping 2167 matching lines @@
                  kTypedDataInt8ArrayViewCid + 15);
   COMPILE_ASSERT(kByteBufferCid == kExternalTypedDataInt8ArrayCid + 14);
   COMPILE_ASSERT(kNullCid == kByteBufferCid + 1);
   return (kNullCid - kTypedDataInt8ArrayCid);
 }
 
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_RAW_OBJECT_H_