Rewrite Object.prototype.toString in C++

src/heap/heap.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_HEAP_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 264 matching lines @@
   V(KeyedStoreMonomorphic_string, "KeyedStoreMonomorphic")       \
   V(last_index_string, "lastIndex")                              \
   V(length_string, "length")                                     \
   V(Map_string, "Map")                                           \
   V(minus_infinity_string, "-Infinity")                          \
   V(minus_zero_string, "-0")                                     \
   V(name_string, "name")                                         \
   V(nan_string, "NaN")                                           \
   V(next_string, "next")                                         \
   V(null_string, "null")                                         \
+  V(null_to_string, "[object Null]")                             \
   V(number_string, "number")                                     \
   V(Number_string, "Number")                                     \
   V(object_string, "object")                                     \
   V(Object_string, "Object")                                     \
   V(ownKeys_string, "ownKeys")                                   \
   V(preventExtensions_string, "preventExtensions")               \
   V(private_api_string, "private_api")                           \
   V(Promise_string, "Promise")                                   \
   V(proto_string, "__proto__")                                   \
   V(prototype_string, "prototype")                               \
@@ skipping 17 matching lines @@
   V(toJSON_string, "toJSON")                                     \
   V(toString_string, "toString")                                 \
   V(true_string, "true")                                         \
   V(uint16x8_string, "uint16x8")                                 \
   V(Uint16x8_string, "Uint16x8")                                 \
   V(uint32x4_string, "uint32x4")                                 \
   V(Uint32x4_string, "Uint32x4")                                 \
   V(uint8x16_string, "uint8x16")                                 \
   V(Uint8x16_string, "Uint8x16")                                 \
   V(undefined_string, "undefined")                               \
+  V(undefined_to_string, "[object Undefined]")                   \
   V(valueOf_string, "valueOf")                                   \
   V(value_string, "value")                                       \
   V(WeakMap_string, "WeakMap")                                   \
   V(WeakSet_string, "WeakSet")                                   \
   V(writable_string, "writable")
 
 #define PRIVATE_SYMBOL_LIST(V)              \
   V(array_iteration_kind_symbol)            \
   V(array_iterator_next_symbol)             \
   V(array_iterator_object_symbol)           \
@@ skipping 2407 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_H_