[runtime] Optimize and unify rest parameters.

src/globals.h

 // 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.
 
 #ifndef V8_GLOBALS_H_
 #define V8_GLOBALS_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 752 matching lines @@
   switch (mode) {
     case TailCallMode::kAllow:
       return os << "ALLOW_TAIL_CALLS";
     case TailCallMode::kDisallow:
       return os << "DISALLOW_TAIL_CALLS";
   }
   UNREACHABLE();
   return os;
 }
 
+// Defines specifics about arguments object or rest parameter creation.
+enum class CreateArgumentsType : uint8_t {
+  kMappedArguments,
+  kUnmappedArguments,
+  kRestParameter
+};
+
+inline size_t hash_value(CreateArgumentsType type) {
+  return bit_cast<uint8_t>(type);
+}
+
+inline std::ostream& operator<<(std::ostream& os, CreateArgumentsType type) {
+  switch (type) {
+    case CreateArgumentsType::kMappedArguments:
+      return os << "MAPPED_ARGUMENTS";
+    case CreateArgumentsType::kUnmappedArguments:
+      return os << "UNMAPPED_ARGUMENTS";
+    case CreateArgumentsType::kRestParameter:
+      return os << "REST_PARAMETER";
+  }
+  UNREACHABLE();
+  return os;
+}
+
 // Used to specify if a macro instruction must perform a smi check on tagged
 // values.
 enum SmiCheckType {
   DONT_DO_SMI_CHECK,
   DO_SMI_CHECK
 };
 
 
 enum ScopeType {
   EVAL_SCOPE,      // The top-level scope for an eval source.
@@ skipping 282 matching lines @@
   return static_cast<uint32_t>(bit_cast<uintptr_t>(address) >>
                                kPointerSizeLog2);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 namespace i = v8::internal;
 
 #endif  // V8_GLOBALS_H_