yield* calls @@iterator on iterable

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/base/platform/platform.h"
 #include "src/bootstrapper.h"
@@ skipping 647 matching lines @@
 
 Expression* ParserTraits::ExpressionFromString(
     int pos, Scanner* scanner,
     AstNodeFactory<AstConstructionVisitor>* factory) {
   const AstRawString* symbol = GetSymbol(scanner);
   if (parser_->fni_ != NULL) parser_->fni_->PushLiteralName(symbol);
   return factory->NewStringLiteral(symbol, pos);
 }
 
 
+Expression* ParserTraits::GetIterator(
+    Expression* iterable, AstNodeFactory<AstConstructionVisitor>* factory) {
+  Expression* iterator_symbol_literal =
+      factory->NewSymbolLiteral("symbolIterator", RelocInfo::kNoPosition);
+  int pos = iterable->position();
+  Expression* prop =
+      factory->NewProperty(iterable, iterator_symbol_literal, pos);
+  Zone* zone = parser_->zone();
+  ZoneList<Expression*>* args = new (zone) ZoneList<Expression*>(0, zone);
+  return factory->NewCall(prop, args, pos);
+}
+
+
 Literal* ParserTraits::GetLiteralTheHole(
     int position, AstNodeFactory<AstConstructionVisitor>* factory) {
   return factory->NewTheHoleLiteral(RelocInfo::kNoPosition);
 }
 
 
 Expression* ParserTraits::ParseV8Intrinsic(bool* ok) {
   return parser_->ParseV8Intrinsic(ok);
 }
 
@@ skipping 2088 matching lines @@
         ast_value_factory_->dot_iterator_string());
     Variable* result = scope_->DeclarationScope()->NewTemporary(
         ast_value_factory_->dot_result_string());
 
     Expression* assign_iterator;
     Expression* next_result;
     Expression* result_done;
     Expression* assign_each;
 
     // var iterator = subject[Symbol.iterator]();
-    {
-      Expression* iterator_symbol_literal =
-          factory()->NewSymbolLiteral("symbolIterator", RelocInfo::kNoPosition);
-      // FIXME(wingo): Unhappily, it will be a common error that the RHS of a
-      // for-of doesn't have a Symbol.iterator property.  We should do better
-      // than informing the user that "undefined is not a function".
-      int pos = subject->position();
-      Expression* iterator_property =
-          factory()->NewProperty(subject, iterator_symbol_literal, pos);
-      ZoneList<Expression*>* iterator_arguments =
-          new(zone()) ZoneList<Expression*>(0, zone());
-      Expression* iterator_call = factory()->NewCall(
-          iterator_property, iterator_arguments, pos);
-      Expression* iterator_proxy = factory()->NewVariableProxy(iterator);
-      assign_iterator = factory()->NewAssignment(
-          Token::ASSIGN, iterator_proxy, iterator_call, RelocInfo::kNoPosition);
-    }
+    assign_iterator = factory()->NewAssignment(
+        Token::ASSIGN, factory()->NewVariableProxy(iterator),
+        GetIterator(subject, factory()), RelocInfo::kNoPosition);
 
     // var result = iterator.next();
     {
       Expression* iterator_proxy = factory()->NewVariableProxy(iterator);
       Expression* next_literal = factory()->NewStringLiteral(
           ast_value_factory_->next_string(), RelocInfo::kNoPosition);
       Expression* next_property = factory()->NewProperty(
           iterator_proxy, next_literal, RelocInfo::kNoPosition);
       ZoneList<Expression*>* next_arguments =
           new(zone()) ZoneList<Expression*>(0, zone());
@@ skipping 2001 matching lines @@
     info()->SetAstValueFactory(ast_value_factory_);
   }
   ast_value_factory_ = NULL;
 
   InternalizeUseCounts();
 
   return (result != NULL);
 }
 
 } }  // namespace v8::internal