[async-iteration] implement Async-from-Sync Iterator

src/code-stub-assembler.h

Index: src/code-stub-assembler.h
diff --git a/src/code-stub-assembler.h b/src/code-stub-assembler.h
index 14cc99596c03bce21782c7a7fa183a6bad9dcd96..2ec1d904654d6b41f3d1b790b8ed627a968b178d 100644
--- a/src/code-stub-assembler.h
+++ b/src/code-stub-assembler.h
@@ -1238,6 +1238,15 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   void Print(const char* prefix, Node* tagged_value);
   inline void Print(Node* tagged_value) { return Print(nullptr, tagged_value); }
 
+  template <class... TArgs>
+  Node* MakeTypeError(MessageTemplate::Template message, Node* context,
+                      TArgs... args) {
+    Node* const make_type_error = LoadContextElement(
+        LoadNativeContext(context), Context::MAKE_TYPE_ERROR_INDEX);
+    return CallJS(CodeFactory::Call(isolate()), context, make_type_error,

[caitp, 2017/02/15 22:18:01]

Maybe it would make sense for MakeTypeError (and friends) to be a runtime
function instead of a C++ builtin. At least it would avoid needing to load it
from native_context, and avoid installing it per context. Would make the CSA
helper simpler

+                  UndefinedConstant(), SmiConstant(message), args...);
+  }
+
  protected:
   void DescriptorLookup(Node* unique_name, Node* descriptors, Node* bitfield3,
                         Label* if_found, Variable* var_name_index,