Perform TODO(gc) cleanup for TODO-lockdown.

src/x64/assembler-x64-inl.h

 // 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 226 matching lines @@
   }
 }
 
 
 void RelocInfo::set_target_address(Address target, Code* code) {
   ASSERT(IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY);
   if (IsCodeTarget(rmode_)) {
     Assembler::set_target_address_at(pc_, target);
     Object* target_code = Code::GetCodeFromTargetAddress(target);
     if (code != NULL) {
-      // TODO(gc) We do not compact code pages.
+      // TODO(1550) We are passing NULL as a slot because code can never be on
+      // evacuation candidate.
       code->GetHeap()->incremental_marking()->RecordWrite(
           code, NULL, HeapObject::cast(target_code));
     }
   } else {
     Memory::Address_at(pc_) = target;
     CPU::FlushICache(pc_, sizeof(Address));
   }
 }
 
 
@@ skipping 209 matching lines @@
   ASSERT(len_ == 1 || len_ == 2);
   int32_t* p = reinterpret_cast<int32_t*>(&buf_[len_]);
   *p = disp;
   len_ += sizeof(int32_t);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_ASSEMBLER_X64_INL_H_