[turbofan] Model arguments object materialization in graph.

src/compiler/js-operator.h

Index: src/compiler/js-operator.h
diff --git a/src/compiler/js-operator.h b/src/compiler/js-operator.h
index 4776a8fe30b88778cc7bde565088919d6ab6a430..2c281e7c14a122364c2ec128ebb8206f0038a920 100644
--- a/src/compiler/js-operator.h
+++ b/src/compiler/js-operator.h
@@ -407,6 +407,32 @@ std::ostream& operator<<(std::ostream&, StorePropertyParameters const&);
 const StorePropertyParameters& StorePropertyParametersOf(const Operator* op);
 
 
+// Defines specifics about arguments object or rest parameter creation. This is
+// used as a parameter by JSCreateArguments operators.
+class CreateArgumentsParameters final {
+ public:
+  enum Type { kMappedArguments, kUnmappedArguments, kRestArray };
+  CreateArgumentsParameters(Type type, int start_index)
+      : type_(type), start_index_(start_index) {}
+
+  Type type() const { return type_; }
+  int start_index() const { return start_index_; }
+
+ private:
+  const Type type_;
+  const int start_index_;
+};
+
+bool operator==(CreateArgumentsParameters const&,
+                CreateArgumentsParameters const&);
+bool operator!=(CreateArgumentsParameters const&,
+                CreateArgumentsParameters const&);
+
+size_t hash_value(CreateArgumentsParameters const&);
+
+std::ostream& operator<<(std::ostream&, CreateArgumentsParameters const&);
+
+
 // Defines shared information for the closure that should be created. This is
 // used as a parameter by JSCreateClosure operators.
 class CreateClosureParameters final {
@@ -469,6 +495,8 @@ class JSOperatorBuilder final : public ZoneObject {
   const Operator* Yield();
 
   const Operator* Create();
+  const Operator* CreateArguments(CreateArgumentsParameters::Type type,
+                                  int start_index);
   const Operator* CreateClosure(Handle<SharedFunctionInfo> shared_info,
                                 PretenureFlag pretenure);
   const Operator* CreateLiteralArray(int literal_flags);