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

src/parser.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/bailout-reason.h"
 #include "src/base/platform/platform.h"
@@ skipping 245 matching lines @@
     cached_parse_data_ = NULL;
   } else {
     DCHECK(info_->cached_data() != NULL);
     if (compile_options() == ScriptCompiler::kConsumeParserCache) {
       cached_parse_data_ = ParseData::FromCachedData(*info_->cached_data());
     }
   }
 }
 
 
-Scope* Parser::NewScope(Scope* parent, ScopeType scope_type) {
+Scope* Parser::NewScope(Scope* parent, ScopeType scope_type,
+                        FunctionKind kind) {
   DCHECK(ast_value_factory());
+  DCHECK((scope_type == FUNCTION_SCOPE && IsValidFunctionKind(kind)) ||
+         kind == kNormalFunction);
   Scope* result =
       new (zone()) Scope(parent, scope_type, ast_value_factory(), zone());
-  result->Initialize();
+  bool uninitialized_this =
+      FLAG_experimental_classes && IsSubclassConstructor(kind);
+  result->Initialize(uninitialized_this);
   return result;
 }
 
 
 FunctionLiteral* Parser::DefaultConstructor(bool call_super, Scope* scope,
                                             int pos, int end_pos) {
   int materialized_literal_count = -1;
   int expected_property_count = -1;
   int handler_count = 0;
   int parameter_count = 0;
   const AstRawString* name = ast_value_factory()->empty_string();
 
-  Scope* function_scope = NewScope(scope, FUNCTION_SCOPE);
+  Scope* function_scope =
+      NewScope(scope, FUNCTION_SCOPE, FunctionKind::kDefaultConstructor);
   function_scope->SetStrictMode(STRICT);
   // Set start and end position to the same value
   function_scope->set_start_position(pos);
   function_scope->set_end_position(pos);
   ZoneList<Statement*>* body = NULL;
 
   {
     AstNodeFactory function_factory(ast_value_factory());
     FunctionState function_state(&function_state_, &scope_, function_scope,
                                  &function_factory);
@@ skipping 3307 matching lines @@
   //   in all normal cases, function declarations are fully hoisted to a
   //   declaration scope and compiled relative to that.
   // - (2) is the case iff the current declaration scope is still the original
   //   one relative to the deserialized scope chain. Otherwise we must be
   //   compiling a function in an inner declaration scope in the eval, e.g. a
   //   nested function, and hoisting works normally relative to that.
   Scope* declaration_scope = scope_->DeclarationScope();
   Scope* original_declaration_scope = original_scope_->DeclarationScope();
   Scope* scope =
       function_type == FunctionLiteral::DECLARATION &&
-      (!allow_harmony_scoping() || strict_mode() == SLOPPY) &&
-      (original_scope_ == original_declaration_scope ||
-       declaration_scope != original_declaration_scope)
-          ? NewScope(declaration_scope, FUNCTION_SCOPE)
-          : NewScope(scope_, FUNCTION_SCOPE);
+              (!allow_harmony_scoping() || strict_mode() == SLOPPY) &&
+              (original_scope_ == original_declaration_scope ||
+               declaration_scope != original_declaration_scope)
+          ? NewScope(declaration_scope, FUNCTION_SCOPE, kind)
+          : NewScope(scope_, FUNCTION_SCOPE, kind);
   ZoneList<Statement*>* body = NULL;
   int materialized_literal_count = -1;
   int expected_property_count = -1;
   int handler_count = 0;
   FunctionLiteral::ParameterFlag duplicate_parameters =
       FunctionLiteral::kNoDuplicateParameters;
   FunctionLiteral::IsParenthesizedFlag parenthesized = parenthesized_function_
       ? FunctionLiteral::kIsParenthesized
       : FunctionLiteral::kNotParenthesized;
   // Parse function body.
@@ skipping 379 matching lines @@
     extends = ParseLeftHandSideExpression(CHECK_OK);
   } else {
     block_scope->set_start_position(scanner()->location().end_pos);
   }
 
   ZoneList<ObjectLiteral::Property*>* properties = NewPropertyList(4, zone());
   FunctionLiteral* constructor = NULL;
   bool has_seen_constructor = false;
 
   Expect(Token::LBRACE, CHECK_OK);
+  const bool has_extends = extends != nullptr;
   while (peek() != Token::RBRACE) {
     if (Check(Token::SEMICOLON)) continue;
     if (fni_ != NULL) fni_->Enter();
     const bool in_class = true;
     const bool is_static = false;
     bool is_computed_name = false;  // Classes do not care about computed
                                     // property names here.
-    ObjectLiteral::Property* property =
-        ParsePropertyDefinition(NULL, in_class, is_static, &is_computed_name,
-                                &has_seen_constructor, CHECK_OK);
+    ObjectLiteral::Property* property = ParsePropertyDefinition(
+        nullptr, in_class, has_extends, is_static, &is_computed_name,
+        &has_seen_constructor, CHECK_OK);
 
     if (has_seen_constructor && constructor == NULL) {
       constructor = GetPropertyValue(property)->AsFunctionLiteral();
       DCHECK_NOT_NULL(constructor);
     } else {
       properties->Add(property, zone());
     }
 
     if (fni_ != NULL) {
       fni_->Infer();
@@ skipping 1306 matching lines @@
     } else {
       const uc16* data = reinterpret_cast<const uc16*>(raw_string->raw_data());
       running_hash = StringHasher::ComputeRunningHash(running_hash, data,
                                                       raw_string->length());
     }
   }
 
   return running_hash;
 }
 } }  // namespace v8::internal