arrange to create prototypes for generators

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 99ff5154e1e6c11c897f4765d18021723782ac2a..088514ab409be4cdfd8fa1bed10e7142ceb375c1 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -393,17 +393,24 @@ class ToNumberStub: public PlatformCodeStub {
 
 class FastNewClosureStub : public PlatformCodeStub {
  public:
-  explicit FastNewClosureStub(LanguageMode language_mode)
-    : language_mode_(language_mode) { }
+  explicit FastNewClosureStub(LanguageMode language_mode, bool is_generator)
+    : language_mode_(language_mode),
+      is_generator_(is_generator) { }
 
   void Generate(MacroAssembler* masm);
 
  private:
+  class StrictModeBits: public BitField<bool, 0, 1> {};
+  class IsGeneratorBits: public BitField<bool, 1, 1> {};
+
   Major MajorKey() { return FastNewClosure; }
-  int MinorKey() { return language_mode_ == CLASSIC_MODE
-        ? kNonStrictMode : kStrictMode; }
+  int MinorKey() {
+    return StrictModeBits::encode(language_mode_ != CLASSIC_MODE) |
+      IsGeneratorBits::encode(is_generator_);
+  }
 
   LanguageMode language_mode_;
+  bool is_generator_;
 };