Calling a generator function returns a generator object

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index f8afdbcc79572899f249f5abb708d2f096ec3f42..cdbb0b90a6d3e7810d6d6dc07097c86a1ae192cd 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -62,6 +62,7 @@
 //           - JSWeakMap
 //           - JSRegExp
 //           - JSFunction
+//           - JSGeneratorIterator

[Michael Starzinger, 2013/04/08 13:14:05]

As discussed offline, the name "JSGeneratorIterator" is confusing. We should
change it to either "JSGeneratorObject" or "JSGeneratorInstance".

Just for the record, I personally would still name it just "JSGenerator" but I
see that we might want to reserve that name if at some point we need an instance
type for generator functions, so you and Andreas convinced me of the above two
alternatives.

 //           - JSModule
 //           - GlobalObject
 //             - JSGlobalObject
@@ -395,6 +396,7 @@ const int kStubMinorKeyBits = kBitsPerInt - kSmiTagSize - kStubMajorKeyBits;
   V(JS_DATE_TYPE)                                                              \
   V(JS_OBJECT_TYPE)                                                            \
   V(JS_CONTEXT_EXTENSION_OBJECT_TYPE)                                          \
+  V(JS_GENERATOR_ITERATOR_TYPE)                                                \
   V(JS_MODULE_TYPE)                                                            \
   V(JS_GLOBAL_OBJECT_TYPE)                                                     \
   V(JS_BUILTINS_OBJECT_TYPE)                                                   \
@@ -726,6 +728,7 @@ enum InstanceType {
   JS_DATE_TYPE,
   JS_OBJECT_TYPE,
   JS_CONTEXT_EXTENSION_OBJECT_TYPE,
+  JS_GENERATOR_ITERATOR_TYPE,
   JS_MODULE_TYPE,
   JS_GLOBAL_OBJECT_TYPE,
   JS_BUILTINS_OBJECT_TYPE,
@@ -953,6 +956,7 @@ class MaybeObject BASE_EMBEDDED {
   V(JSReceiver)                                \
   V(JSObject)                                  \
   V(JSContextExtensionObject)                  \
+  V(JSGeneratorIterator)                       \
   V(JSModule)                                  \
   V(Map)                                       \
   V(DescriptorArray)                           \
@@ -6238,6 +6242,41 @@ class SharedFunctionInfo: public HeapObject {
 };
 
 
+// Representation for generator iterators.
+class JSGeneratorIterator: public JSObject {
+ public:
+  // [function]: The function corresponding to this iterator.
+  DECL_ACCESSORS(function, JSFunction)
+
+  // [context]: The context of the suspended computation, or Smi 0.
+  DECL_ACCESSORS(context, Object)
+
+  // [continuation]: Offset into code of continuation.
+  inline int continuation();
+  inline void set_continuation(int continuation);
+
+  // [operands]: Saved operand stack: FixedArray or Smi 0.
+  DECL_ACCESSORS(operand_stack, Object)
+
+  // Casting.
+  static inline JSGeneratorIterator* cast(Object* obj);
+
+  // Dispatched behavior.
+  DECLARE_PRINTER(JSGeneratorIterator)
+  DECLARE_VERIFIER(JSGeneratorIterator)
+
+  // Layout description.
+  static const int kFunctionOffset = JSObject::kHeaderSize;
+  static const int kContextOffset = kFunctionOffset + kPointerSize;
+  static const int kContinuationOffset = kContextOffset + kPointerSize;
+  static const int kOperandStackOffset = kContinuationOffset + kPointerSize;
+  static const int kSize = kOperandStackOffset + kPointerSize;
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(JSGeneratorIterator);
+};
+
+
 // Representation for module instance objects.
 class JSModule: public JSObject {
  public: