Implement code stub for object literal creation.

src/x64/full-codegen-x64.cc

 // 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 1358 matching lines @@
   if ((size % (2 * kPointerSize)) != 0) {
     __ movq(rdx, FieldOperand(rbx, size - kPointerSize));
     __ movq(FieldOperand(rax, size - kPointerSize), rdx);
   }
   context()->Plug(rax);
 }
 
 
 void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
   Comment cmnt(masm_, "[ ObjectLiteral");
+  Handle<FixedArray> constant_properties = expr->constant_properties();
   __ movq(rdi, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
   __ push(FieldOperand(rdi, JSFunction::kLiteralsOffset));
   __ Push(Smi::FromInt(expr->literal_index()));
-  __ Push(expr->constant_properties());
+  __ Push(constant_properties);
   int flags = expr->fast_elements()
       ? ObjectLiteral::kFastElements
       : ObjectLiteral::kNoFlags;
   flags |= expr->has_function()
       ? ObjectLiteral::kHasFunction
       : ObjectLiteral::kNoFlags;
   __ Push(Smi::FromInt(flags));
+  int properties_count = constant_properties->length() / 2;
   if (expr->depth() > 1) {
     __ CallRuntime(Runtime::kCreateObjectLiteral, 4);
+  } else if (flags != ObjectLiteral::kFastElements ||
+      properties_count > FastCloneShallowObjectStub::kMaximumClonedProperties) {
+    __ CallRuntime(Runtime::kCreateObjectLiteralShallow, 4);
   } else {
-    __ CallRuntime(Runtime::kCreateObjectLiteralShallow, 4);
+    FastCloneShallowObjectStub stub(properties_count);
+    __ CallStub(&stub);
   }
 
   // If result_saved is true the result is on top of the stack.  If
   // result_saved is false the result is in rax.
   bool result_saved = false;
 
   // Mark all computed expressions that are bound to a key that
   // is shadowed by a later occurrence of the same key. For the
   // marked expressions, no store code is emitted.
   expr->CalculateEmitStore();
@@ skipping 2909 matching lines @@
   *context_length = 0;
   return previous_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64