[turbofan] Build s/NULL/nullptr/g and CHECK(x != nullptr) to CHECK_NOT_NULL(x).

src/compiler/x64/code-generator-x64.cc

 // Copyright 2013 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.
 
 #include "src/compiler/code-generator.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
@@ skipping 1903 matching lines @@
   }
   size_t pop_size = descriptor->StackParameterCount() * kPointerSize;
   // Might need rcx for scratch if pop_size is too big.
   DCHECK_EQ(0u, descriptor->CalleeSavedRegisters() & rcx.bit());
   __ Ret(static_cast<int>(pop_size), rcx);
 }
 
 
 void CodeGenerator::AssembleMove(InstructionOperand* source,
                                  InstructionOperand* destination) {
-  X64OperandConverter g(this, NULL);
+  X64OperandConverter g(this, nullptr);
   // Dispatch on the source and destination operand kinds.  Not all
   // combinations are possible.
   if (source->IsRegister()) {
     DCHECK(destination->IsRegister() || destination->IsStackSlot());
     Register src = g.ToRegister(source);
     if (destination->IsRegister()) {
       __ movq(g.ToRegister(destination), src);
     } else {
       __ movq(g.ToOperand(destination), src);
     }
@@ skipping 100 matching lines @@
       __ Movsd(dst, xmm0);
     }
   } else {
     UNREACHABLE();
   }
 }
 
 
 void CodeGenerator::AssembleSwap(InstructionOperand* source,
                                  InstructionOperand* destination) {
-  X64OperandConverter g(this, NULL);
+  X64OperandConverter g(this, nullptr);
   // Dispatch on the source and destination operand kinds.  Not all
   // combinations are possible.
   if (source->IsRegister() && destination->IsRegister()) {
     // Register-register.
     __ xchgq(g.ToRegister(source), g.ToRegister(destination));
   } else if (source->IsRegister() && destination->IsStackSlot()) {
     Register src = g.ToRegister(source);
     Operand dst = g.ToOperand(destination);
     __ xchgq(src, dst);
   } else if ((source->IsStackSlot() && destination->IsStackSlot()) ||
@@ skipping 52 matching lines @@
     int padding_size = last_lazy_deopt_pc_ + space_needed - current_pc;
     __ Nop(padding_size);
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8