Add bit_field3 to Map objects

src/x64/macro-assembler-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 2583 matching lines @@
   movq(temp_xmm_reg, temp_reg);
   addsd(temp_xmm_reg, input_reg);
   cvttsd2si(result_reg, temp_xmm_reg);
   testl(result_reg, Immediate(0xFFFFFF00));
   j(zero, &done, Label::kNear);
   Set(result_reg, 255);
   bind(&done);
 }
 
 
+void MacroAssembler::LoadInstanceDescriptors(Register map,
+                                             Register descriptors) {
+  movq(descriptors, FieldOperand(map,
+                                 Map::kInstanceDescriptorsOrBitField3Offset));
+  Label not_smi;
+  JumpIfNotSmi(descriptors, &not_smi, Label::kNear);
+  Move(descriptors, isolate()->factory()->empty_descriptor_array());
+  bind(&not_smi);
+}
+
+
 void MacroAssembler::DispatchMap(Register obj,
                                  Handle<Map> map,
                                  Handle<Code> success,
                                  SmiCheckType smi_check_type) {
   Label fail;
   if (smi_check_type == DO_SMI_CHECK) {
     JumpIfSmi(obj, &fail);
   }
   Cmp(FieldOperand(obj, HeapObject::kMapOffset), map);
   j(equal, success, RelocInfo::CODE_TARGET);
@@ skipping 1085 matching lines @@
   CPU::FlushICache(address_, size_);
 
   // Check that the code was patched as expected.
   ASSERT(masm_.pc_ == address_ + size_);
   ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64