new classes: special construct stub for derived classs and TDZ for `this`.

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 760 matching lines @@
 
 enum Signedness { kSigned, kUnsigned };
 
 
 enum FunctionKind {
   kNormalFunction = 0,
   kArrowFunction = 1,
   kGeneratorFunction = 2,
   kConciseMethod = 4,
   kConciseGeneratorMethod = kGeneratorFunction | kConciseMethod,
-  kDefaultConstructor = 8
+  kDefaultConstructor = 8,
+  kSubclassConstructor = 16
 };
 
 
 inline bool IsValidFunctionKind(FunctionKind kind) {
   return kind == FunctionKind::kNormalFunction ||
          kind == FunctionKind::kArrowFunction ||
          kind == FunctionKind::kGeneratorFunction ||
          kind == FunctionKind::kConciseMethod ||
          kind == FunctionKind::kConciseGeneratorMethod ||
-         kind == FunctionKind::kDefaultConstructor;
+         kind == FunctionKind::kDefaultConstructor ||
+         kind == FunctionKind::kSubclassConstructor;
 }
 
 
 inline bool IsArrowFunction(FunctionKind kind) {
   DCHECK(IsValidFunctionKind(kind));
   return kind & FunctionKind::kArrowFunction;
 }
 
 
 inline bool IsGeneratorFunction(FunctionKind kind) {
   DCHECK(IsValidFunctionKind(kind));
   return kind & FunctionKind::kGeneratorFunction;
 }
 
 
 inline bool IsConciseMethod(FunctionKind kind) {
   DCHECK(IsValidFunctionKind(kind));
   return kind & FunctionKind::kConciseMethod;
 }
 
 
 inline bool IsDefaultConstructor(FunctionKind kind) {
   DCHECK(IsValidFunctionKind(kind));
   return kind & FunctionKind::kDefaultConstructor;
 }
 
-
+inline bool IsSubclassConstructor(FunctionKind kind) {
+  DCHECK(IsValidFunctionKind(kind));
+  return kind & FunctionKind::kSubclassConstructor;
+}
 } }  // namespace v8::internal
 
 namespace i = v8::internal;
 
 #endif  // V8_GLOBALS_H_