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

src/compiler/graph-visualizer.cc

Index: src/compiler/graph-visualizer.cc
diff --git a/src/compiler/graph-visualizer.cc b/src/compiler/graph-visualizer.cc
index 36462e85c8fe08479a3e9cc29c2be72ee4818211..07851768b3d432bbc91dc65b6aa3b3aee8b3a8e4 100644
--- a/src/compiler/graph-visualizer.cc
+++ b/src/compiler/graph-visualizer.cc
@@ -41,7 +41,7 @@ FILE* OpenVisualizerLogFile(CompilationInfo* info, const char* phase,
                '_');
 
   EmbeddedVector<char, 256> full_filename;
-  if (phase == NULL) {
+  if (phase == nullptr) {
     SNPrintF(full_filename, "%s.%s", filename.start(), suffix);
   } else {
     SNPrintF(full_filename, "%s-%s.%s", filename.start(), phase, suffix);
@@ -50,9 +50,9 @@ FILE* OpenVisualizerLogFile(CompilationInfo* info, const char* phase,
 }
 
 
-static int SafeId(Node* node) { return node == NULL ? -1 : node->id(); }
+static int SafeId(Node* node) { return node == nullptr ? -1 : node->id(); }
 static const char* SafeMnemonic(Node* node) {
-  return node == NULL ? "null" : node->op()->mnemonic();
+  return node == nullptr ? "null" : node->op()->mnemonic();
 }
 
 #define DEAD_COLOR "#999999"
@@ -158,7 +158,7 @@ class JSONGraphEdgeWriter {
   void PrintEdges(Node* node) {
     for (int i = 0; i < node->InputCount(); i++) {
       Node* input = node->InputAt(i);
-      if (input == NULL) continue;
+      if (input == nullptr) continue;
       PrintEdge(node, i, input);
     }
   }
@@ -169,7 +169,7 @@ class JSONGraphEdgeWriter {
     } else {
       os_ << ",\n";
     }
-    const char* edge_type = NULL;
+    const char* edge_type = nullptr;
     if (index < NodeProperties::FirstValueIndex(from)) {
       edge_type = "unknown";
     } else if (index < NodeProperties::FirstContextIndex(from)) {
@@ -397,7 +397,7 @@ void GraphC1Visualizer::PrintSchedule(const char* phase,
     PrintIndent();
     os_ << "flags\n";
 
-    if (current->dominator() != NULL) {
+    if (current->dominator() != nullptr) {
       PrintBlockProperty("dominator", current->dominator()->rpo_number());
     }
 
@@ -455,7 +455,7 @@ void GraphC1Visualizer::PrintSchedule(const char* phase,
           os_ << " ";
           PrintType(node);
         }
-        if (positions != NULL) {
+        if (positions != nullptr) {
           SourcePosition position = positions->GetSourcePosition(node);
           if (position.IsKnown()) {
             os_ << " pos:" << position.raw();
@@ -468,7 +468,7 @@ void GraphC1Visualizer::PrintSchedule(const char* phase,
       if (control != BasicBlock::kNone) {
         PrintIndent();
         os_ << "0 0 ";
-        if (current->control_input() != NULL) {
+        if (current->control_input() != nullptr) {
           PrintNode(current->control_input());
         } else {
           os_ << -1 - current->rpo_number() << " Goto";
@@ -477,7 +477,7 @@ void GraphC1Visualizer::PrintSchedule(const char* phase,
         for (BasicBlock* successor : current->successors()) {
           os_ << " B" << successor->rpo_number();
         }
-        if (FLAG_trace_turbo_types && current->control_input() != NULL) {
+        if (FLAG_trace_turbo_types && current->control_input() != nullptr) {
           os_ << " ";
           PrintType(current->control_input());
         }
@@ -485,7 +485,7 @@ void GraphC1Visualizer::PrintSchedule(const char* phase,
       }
     }
 
-    if (instructions != NULL) {
+    if (instructions != nullptr) {
       Tag LIR_tag(this, "LIR");
       for (int j = instruction_block->first_instruction_index();
            j <= instruction_block->last_instruction_index(); j++) {
@@ -531,7 +531,7 @@ void GraphC1Visualizer::PrintLiveRangeChain(TopLevelLiveRange* range,
 
 void GraphC1Visualizer::PrintLiveRange(LiveRange* range, const char* type,
                                        int vreg) {
-  if (range != NULL && !range->IsEmpty()) {
+  if (range != nullptr && !range->IsEmpty()) {
     PrintIndent();
     os_ << vreg << ":" << range->relative_id() << " " << type;
     if (range->HasRegisterAssigned()) {
@@ -571,7 +571,7 @@ void GraphC1Visualizer::PrintLiveRange(LiveRange* range, const char* type,
     }
 
     UsePosition* current_pos = range->first_pos();
-    while (current_pos != NULL) {
+    while (current_pos != nullptr) {
       if (current_pos->RegisterIsBeneficial() || FLAG_trace_all_uses) {
         os_ << " " << current_pos->pos().value() << " M";
       }