Calling a generator function returns a generator object

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index fa550a5b7bc8829e905072e7cad4eb77c65c97c7..013cd60802451f14fe9f0956d2c0632ec4e2c937 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -284,6 +284,14 @@ void FullCodeGenerator::Generate() {
       __ bind(&ok);
     }
 
+    if (function()->is_generator()) {

[wingo, 2013/04/03 16:36:24]

How to communicate this iterator object from its allocation to the "yield" call
sites?  I think the answer is to use a local variable.

Instead of fabricating a runtime call here, I think we probably need to add some
nodes to the AST to CallRuntime(CreateJSGeneratorIterator), store it in a
variable, and record that variable in the FunctionState; and follow it with a
runtime call to SuspendGenerator in the prologue, passing the saved generator
iterator as a param.

With forced context allocation, an added local would get put in the context
object, leading to the silliness where the context has a pointer to the iterator
and vice versa.  Oh well; probably something we can live with.

+      Comment cmnt(masm_, "[ Generator Iterator");
+      __ push(Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
+      __ CallRuntime(Runtime::kCreateJSGeneratorIterator, 1);
+      // TODO(wingo): Suspend the generator.
+      EmitReturnSequence();
+    }
+
     { Comment cmnt(masm_, "[ Body");
       ASSERT(loop_depth() == 0);
       VisitStatements(function()->body());