Baseline for-of implementation

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index 27f7a8200d49c2ab0a54400ddbccdb438eb9c210..fa24bf703bc6f62a039580db9731c0a6ae131c85 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -2636,6 +2636,78 @@ bool Parser::CheckInOrOf(ForEachStatement::VisitMode* visit_mode) {
 }
 
 
+void Parser::InitializeForEachStatement(ForEachStatement* stmt,
+                                        Expression* each,
+                                        Expression* subject,
+                                        Statement* body) {
+  ForOfStatement* for_of = stmt->AsForOfStatement();
+
+  if (for_of != NULL) {
+    Factory* heap_factory = isolate()->factory();
+    Handle<String> iterator_str = heap_factory->InternalizeOneByteString(
+        STATIC_ASCII_VECTOR(".iterator"));
+    Handle<String> result_str = heap_factory->InternalizeOneByteString(
+        STATIC_ASCII_VECTOR(".result"));
+    Variable* iterator =
+        top_scope_->DeclarationScope()->NewTemporary(iterator_str);
+    Variable* result = top_scope_->DeclarationScope()->NewTemporary(result_str);
+
+    Expression* assign_iterator;
+    Expression* next_result;
+    Expression* result_done;
+    Expression* assign_each;
+
+    // var iterator = iterable;
+    {
+      Expression* iterator_proxy = factory()->NewVariableProxy(iterator);
+      assign_iterator = factory()->NewAssignment(
+          Token::ASSIGN, iterator_proxy, subject, RelocInfo::kNoPosition);
+    }
+
+    // var result = iterator.next();
+    {
+      Expression* iterator_proxy = factory()->NewVariableProxy(iterator);
+      Expression* next_literal =
+          factory()->NewLiteral(heap_factory->next_string());
+      Expression* next_property = factory()->NewProperty(
+          iterator_proxy, next_literal, RelocInfo::kNoPosition);
+      ZoneList<Expression*>* next_arguments =
+          new(zone()) ZoneList<Expression*>(0, zone());
+      Expression* next_call = factory()->NewCall(
+          next_property, next_arguments, RelocInfo::kNoPosition);
+      Expression* result_proxy = factory()->NewVariableProxy(result);
+      next_result = factory()->NewAssignment(
+          Token::ASSIGN, result_proxy, next_call, RelocInfo::kNoPosition);
+    }
+
+    // result.done
+    {
+      Expression* done_literal =
+          factory()->NewLiteral(heap_factory->done_string());
+      Expression* result_proxy = factory()->NewVariableProxy(result);
+      result_done = factory()->NewProperty(
+          result_proxy, done_literal, RelocInfo::kNoPosition);
+    }
+
+    // each = result.value
+    {
+      Expression* value_literal =
+          factory()->NewLiteral(heap_factory->value_string());
+      Expression* result_proxy = factory()->NewVariableProxy(result);
+      Expression* result_value = factory()->NewProperty(
+          result_proxy, value_literal, RelocInfo::kNoPosition);
+      assign_each = factory()->NewAssignment(
+          Token::ASSIGN, each, result_value, RelocInfo::kNoPosition);
+    }
+
+    for_of->Initialize(each, subject, body,
+                       assign_iterator, next_result, result_done, assign_each);
+  } else {
+    stmt->Initialize(each, subject, body);
+  }
+}
+
+
 Statement* Parser::ParseForStatement(ZoneStringList* labels, bool* ok) {
   // ForStatement ::
   //   'for' '(' Expression? ';' Expression? ';' Expression? ')' Statement
@@ -2670,7 +2742,7 @@ Statement* Parser::ParseForStatement(ZoneStringList* labels, bool* ok) {
         VariableProxy* each =
             top_scope_->NewUnresolved(factory(), name, interface);
         Statement* body = ParseStatement(NULL, CHECK_OK);
-        loop->Initialize(each, enumerable, body);
+        InitializeForEachStatement(loop, each, enumerable, body);
         Block* result = factory()->NewBlock(NULL, 2, false);
         result->AddStatement(variable_statement, zone());
         result->AddStatement(loop, zone());
@@ -2734,7 +2806,7 @@ Statement* Parser::ParseForStatement(ZoneStringList* labels, bool* ok) {
         body_block->AddStatement(variable_statement, zone());
         body_block->AddStatement(assignment_statement, zone());
         body_block->AddStatement(body, zone());
-        loop->Initialize(temp_proxy, enumerable, body_block);
+        InitializeForEachStatement(loop, temp_proxy, enumerable, body_block);
         top_scope_ = saved_scope;
         for_scope->set_end_position(scanner().location().end_pos);
         for_scope = for_scope->FinalizeBlockScope();
@@ -2766,7 +2838,7 @@ Statement* Parser::ParseForStatement(ZoneStringList* labels, bool* ok) {
         Expect(Token::RPAREN, CHECK_OK);
 
         Statement* body = ParseStatement(NULL, CHECK_OK);
-        loop->Initialize(expression, enumerable, body);
+        InitializeForEachStatement(loop, expression, enumerable, body);
         top_scope_ = saved_scope;
         for_scope->set_end_position(scanner().location().end_pos);
         for_scope = for_scope->FinalizeBlockScope();