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 fae20831746354eda611664a88b04013497a7224..d20eba58fc91117e4bac2bd39898905b1c25cd3c 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -62,6 +62,7 @@
 //           - JSWeakMap
 //           - JSRegExp
 //           - JSFunction
+//           - JSGeneratorObject
 //           - 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_OBJECT_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_OBJECT_TYPE,
   JS_MODULE_TYPE,
   JS_GLOBAL_OBJECT_TYPE,
   JS_BUILTINS_OBJECT_TYPE,
@@ -953,13 +956,14 @@ class MaybeObject BASE_EMBEDDED {
   V(JSReceiver)                                \
   V(JSObject)                                  \
   V(JSContextExtensionObject)                  \
+  V(JSGeneratorObject)                         \
   V(JSModule)                                  \
   V(Map)                                       \
   V(DescriptorArray)                           \
   V(TransitionArray)                           \
   V(DeoptimizationInputData)                   \
   V(DeoptimizationOutputData)                  \
-  V(DependentCode)                            \
+  V(DependentCode)                             \
   V(TypeFeedbackCells)                         \
   V(FixedArray)                                \
   V(FixedDoubleArray)                          \
@@ -6255,6 +6259,40 @@ class SharedFunctionInfo: public HeapObject {
 };
 
 
+class JSGeneratorObject: public JSObject {
+ public:
+  // [function]: The function corresponding to this generator object.
+  DECL_ACCESSORS(function, JSFunction)
+
+  // [context]: The context of the suspended computation, or undefined.
+  DECL_ACCESSORS(context, Object)
+
+  // [continuation]: Offset into code of continuation.
+  inline int continuation();
+  inline void set_continuation(int continuation);
+
+  // [operands]: Saved operand stack.
+  DECL_ACCESSORS(operand_stack, FixedArray)
+
+  // Casting.
+  static inline JSGeneratorObject* cast(Object* obj);
+
+  // Dispatched behavior.
+  DECLARE_PRINTER(JSGeneratorObject)
+  DECLARE_VERIFIER(JSGeneratorObject)
+
+  // 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(JSGeneratorObject);
+};
+
+
 // Representation for module instance objects.
 class JSModule: public JSObject {
  public: