Fix object initialization when slack tracking for it's map is still enabled.

src/x64/macro-assembler-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 4945 matching lines @@
     incp(source);
     incp(destination);
     decl(length);
     j(not_zero, &short_loop);
   }
 
   bind(&done);
 }
 
 
-void MacroAssembler::InitializeFieldsWithFiller(Register start_offset,
-                                                Register end_offset,
+void MacroAssembler::InitializeFieldsWithFiller(Register current_address,
+                                                Register end_address,
                                                 Register filler) {
   Label loop, entry;
   jmp(&entry);
   bind(&loop);
-  movp(Operand(start_offset, 0), filler);
-  addp(start_offset, Immediate(kPointerSize));
+  movp(Operand(current_address, 0), filler);
+  addp(current_address, Immediate(kPointerSize));
   bind(&entry);
-  cmpp(start_offset, end_offset);
+  cmpp(current_address, end_address);
   j(below, &loop);
 }
 
 
 void MacroAssembler::LoadContext(Register dst, int context_chain_length) {
   if (context_chain_length > 0) {
     // Move up the chain of contexts to the context containing the slot.
     movp(dst, Operand(rsi, Context::SlotOffset(Context::PREVIOUS_INDEX)));
     for (int i = 1; i < context_chain_length; i++) {
       movp(dst, Operand(dst, Context::SlotOffset(Context::PREVIOUS_INDEX)));
@@ skipping 527 matching lines @@
   movl(rax, dividend);
   shrl(rax, Immediate(31));
   addl(rdx, rax);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64