VM: Reland Inline instance object hash code into object header on 64bit.

runtime/lib/object.cc

 // Copyright (c) 2011, 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/bootstrap_natives.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/code_patcher.h"
 #include "vm/exceptions.h"
 #include "vm/heap.h"
@@ skipping 24 matching lines @@
   // Implemented in the flow graph builder.
   UNREACHABLE();
   return Object::null();
 }
 
 
 DEFINE_NATIVE_ENTRY(Object_getHash, 1) {
   // Please note that no handle is created for the argument.
   // This is safe since the argument is only used in a tail call.
   // The performance benefit is more than 5% when using hashCode.
+#if defined(HASH_IN_OBJECT_HEADER)
+  return Smi::New(Object::GetCachedHash(arguments->NativeArgAt(0)));
+#else
   Heap* heap = isolate->heap();
   ASSERT(arguments->NativeArgAt(0)->IsDartInstance());
   return Smi::New(heap->GetHash(arguments->NativeArgAt(0)));
+#endif
 }
 
 
 DEFINE_NATIVE_ENTRY(Object_setHash, 2) {
+  GET_NON_NULL_NATIVE_ARGUMENT(Smi, hash, arguments->NativeArgAt(1));
+#if defined(HASH_IN_OBJECT_HEADER)
+  Object::SetCachedHash(arguments->NativeArgAt(0), hash.Value());
+#else
   const Instance& instance = Instance::CheckedHandle(arguments->NativeArgAt(0));
-  GET_NON_NULL_NATIVE_ARGUMENT(Smi, hash, arguments->NativeArgAt(1));
   Heap* heap = isolate->heap();
   heap->SetHash(instance.raw(), hash.Value());
+#endif
   return Object::null();
 }
 
 
 DEFINE_NATIVE_ENTRY(Object_toString, 1) {
   const Instance& instance = Instance::CheckedHandle(arguments->NativeArgAt(0));
   if (instance.IsString()) {
     return instance.raw();
   }
   const char* c_str = instance.ToCString();
@@ skipping 319 matching lines @@
   for (intptr_t i = split; i < len; i++) {
     type = function_type_arguments.IsNull()
                ? Type::DynamicType()
                : function_type_arguments.TypeAt(i - split);
     result.SetTypeAt(i, type);
   }
   return result.Canonicalize();
 }
 
 }  // namespace dart