Add support for sync* and yield

runtime/vm/object.h

Index: runtime/vm/object.h
===================================================================
--- runtime/vm/object.h	(revision 43515)
+++ runtime/vm/object.h	(working copy)
@@ -2152,6 +2152,28 @@
     return modifier() == RawFunction::kAsync;
   }
 
+  bool IsAsyncClosure() const {
+    return is_generated_body() &&
+        Function::Handle(parent_function()).IsAsyncFunction();
+  }
+
+  bool IsGenerator() const {
+    return (modifier() & RawFunction::kGeneratorBit) != 0;
+  }
+
+  bool IsSyncGenerator() const {
+    return modifier() == RawFunction::kSyncGen;
+  }
+
+  bool IsSyncGenClosure() const {
+    return is_generated_body() &&
+        Function::Handle(parent_function()).IsSyncGenerator();
+  }
+
+  bool IsAsyncOrGenerator() const {
+    return modifier() != RawFunction::kNoModifier;
+  }
+
   static intptr_t InstanceSize() {
     return RoundedAllocationSize(sizeof(RawFunction));
   }
@@ -2239,7 +2261,7 @@
   V(External, is_external)                                                     \
   V(AllowsHoistingCheckClass, allows_hoisting_check_class)                     \
   V(AllowsBoundsCheckGeneralization, allows_bounds_check_generalization)       \
-  V(AsyncClosure, is_async_closure)                                            \
+  V(GeneratedBody, is_generated_body)                                          \
   V(AlwaysInline, always_inline)                                               \
   V(PolymorphicTarget, is_polymorphic_target)                                  \
 
@@ -2262,6 +2284,8 @@
     kRecognizedTagPos = kKindTagPos + kKindTagSize,
     kRecognizedTagSize = 8,
     kModifierPos = kRecognizedTagPos + kRecognizedTagSize,
+    kModifierSize = 2,
+    kLastModifierBitPos = kModifierPos + (kModifierSize - 1),
     // Single bit sized fields start here.
 #define DECLARE_BIT(name, _) k##name##Bit,
 FOR_EACH_FUNCTION_KIND_BIT(DECLARE_BIT)
@@ -2277,11 +2301,14 @@
 
   class KindBits :
     public BitField<RawFunction::Kind, kKindTagPos, kKindTagSize> {};  // NOLINT
+
   class RecognizedBits : public BitField<MethodRecognizer::Kind,
                                          kRecognizedTagPos,
                                          kRecognizedTagSize> {};
   class ModifierBits :
-      public BitField<RawFunction::AsyncModifier, kModifierPos, 1> {};  // NOLINT
+    public BitField<RawFunction::AsyncModifier,
+                   kModifierPos,
+                   kModifierSize> {};  // NOLINT
 
 #define DEFINE_BIT(name, _) \
   class name##Bit : public BitField<bool, k##name##Bit, 1> {};