WIP [esnext] implement async iteration proposal

src/parsing/parser.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_PARSER_H_
 #define V8_PARSING_PARSER_H_
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/base/compiler-specific.h"
@@ skipping 431 matching lines @@
     int recursion_level_;
     bool* ok_;
 
     DEFINE_AST_VISITOR_MEMBERS_WITHOUT_STACKOVERFLOW()
   };
 
   // !%_IsJSReceiver(result = iterator.next()) &&
   //     %ThrowIteratorResultNotAnObject(result)
   Expression* BuildIteratorNextResult(Expression* iterator, Variable* result,
                                       int pos);
+  Expression* AwaitIteratorNextResult(Expression* iterator, Variable* result,
+                                      int pos);
 
   // Initialize the components of a for-in / for-of statement.
   Statement* InitializeForEachStatement(ForEachStatement* stmt,
                                         Expression* each, Expression* subject,
                                         Statement* body, int each_keyword_pos);
   Statement* InitializeForOfStatement(ForOfStatement* stmt, Expression* each,
                                       Expression* iterable, Statement* body,
                                       bool finalize,
                                       int next_result_pos = kNoSourcePosition);
+  Statement* InitializeForAwaitOfStatement(
+      ForEachStatement* for_of, Expression* each, Expression* iterable,
+      Statement* body, bool finalize, int next_result_pos = kNoSourcePosition);
   Block* RewriteForVarInLegacy(const ForInfo& for_info);
   void DesugarBindingInForEachStatement(ForInfo* for_info, Block** body_block,
                                         Expression** each_variable, bool* ok);
   Block* CreateForEachStatementTDZ(Block* init_block, const ForInfo& for_info,
                                    bool* ok);
 
   Statement* DesugarLexicalBindingsInForStatement(
       ForStatement* loop, Statement* init, Expression* cond, Statement* next,
       Statement* body, Scope* inner_scope, const ForInfo& for_info, bool* ok);
 
@@ skipping 161 matching lines @@
   Expression* NewThrowError(Runtime::FunctionId function_id,
                             MessageTemplate::Template message,
                             const AstRawString* arg, int pos);
 
   void FinalizeIteratorUse(Scope* use_scope, Variable* completion,
                            Expression* condition, Variable* iter,
                            Block* iterator_use, Block* result);
 
   Statement* FinalizeForOfStatement(ForOfStatement* loop, Variable* completion,
                                     int pos);
+  Statement* FinalizeForAwaitOfStatement(ForOfStatement* loop,
+                                         Variable* completion, int pos);
   void BuildIteratorClose(ZoneList<Statement*>* statements, Variable* iterator,
                           Variable* input, Variable* output);
   void BuildIteratorCloseForCompletion(Scope* scope,
                                        ZoneList<Statement*>* statements,
                                        Variable* iterator,
                                        Expression* completion);
   Statement* CheckCallable(Variable* var, Expression* error, int pos);
 
   V8_INLINE Expression* RewriteAwaitExpression(Expression* value, int pos);
   V8_INLINE void PrepareAsyncFunctionBody(ZoneList<Statement*>* body,
@@ skipping 522 matching lines @@
 
  private:
   ParserTarget** variable_;
   ParserTarget* previous_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_PARSER_H_