Implement ES2015 labelled function declaration restrictions

src/parsing/preparser.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_PARSING_PREPARSER_H
 #define V8_PARSING_PREPARSER_H
 
 #include "src/ast/scopes.h"
 #include "src/bailout-reason.h"
 #include "src/hashmap.h"
@@ skipping 991 matching lines @@
   // are either being counted in the preparser data, or is important
   // to throw the correct syntax error exceptions.
 
   // All ParseXXX functions take as the last argument an *ok parameter
   // which is set to false if parsing failed; it is unchanged otherwise.
   // By making the 'exception handling' explicit, we are forced to check
   // for failure at the call sites.
   Statement ParseStatementListItem(bool* ok);
   void ParseStatementList(int end_token, bool* ok,
                           Scanner::BookmarkScope* bookmark = nullptr);
-  Statement ParseStatement(bool* ok);
-  Statement ParseSubStatement(bool* ok);
+  Statement ParseStatement(AllowLabelledFunctionStatement, bool* ok);
+  Statement ParseSubStatement(AllowLabelledFunctionStatement, bool* ok);
   Statement ParseScopedStatement(bool legacy, bool* ok);
   Statement ParseFunctionDeclaration(bool* ok);
   Statement ParseClassDeclaration(bool* ok);
   Statement ParseBlock(bool* ok);
   Statement ParseVariableStatement(VariableDeclarationContext var_context,
                                    bool* ok);
   Statement ParseVariableDeclarations(VariableDeclarationContext var_context,
                                       int* num_decl, bool* is_lexical,
                                       bool* is_binding_pattern,
                                       Scanner::Location* first_initializer_loc,
                                       Scanner::Location* bindings_loc,
                                       bool* ok);
-  Statement ParseExpressionOrLabelledStatement(bool* ok);
+  Statement ParseExpressionOrLabelledStatement(AllowLabelledFunctionStatement,
+                                               bool* ok);
   Statement ParseIfStatement(bool* ok);
   Statement ParseContinueStatement(bool* ok);
   Statement ParseBreakStatement(bool* ok);
   Statement ParseReturnStatement(bool* ok);
   Statement ParseWithStatement(bool* ok);
   Statement ParseSwitchStatement(bool* ok);
   Statement ParseDoWhileStatement(bool* ok);
   Statement ParseWhileStatement(bool* ok);
   Statement ParseForStatement(bool* ok);
   Statement ParseThrowStatement(bool* ok);
@@ skipping 112 matching lines @@
     const PreParserFormalParameters& parameters, FunctionKind kind,
     FunctionLiteral::FunctionType function_type, bool* ok) {
   return pre_parser_->ParseEagerFunctionBody(function_name, pos, parameters,
                                              kind, function_type, ok);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_PREPARSER_H