[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 c68ff947ff7eaf2393f02b80f0eee27a09280ced..a59b25b610dcac6e12d000d4ce7e5d7282788188 100644
--- a/src/code-stub-assembler.h
+++ b/src/code-stub-assembler.h
@@ -992,6 +992,11 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
                          Label* if_found, Variable* var_value,
                          Label* if_not_found, Label* if_bailout);
 
+  Node* GetProperty(Node* context, Node* receiver, Handle<Name> name) {
+    return CallStub(CodeFactory::GetProperty(isolate()), context, receiver,
+                    HeapConstant(name));
+  }
+
   void LoadPropertyFromFastObject(Node* object, Node* map, Node* descriptors,
                                   Node* name_index, Variable* var_details,
                                   Variable* var_value);
@@ -1241,6 +1246,15 @@ 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,

[jgruber, 2017/02/17 12:28:23]

Great to have this and the above. We should update current use sites in a
separate CL.

+                      TArgs... args) {

[jgruber, 2017/02/17 12:28:23]

The MakeTypeError builtin can only handle up to 3 args, please add a
STATIC_ASSERT(sizeof...(TArgs) <= 3);

[caitp, 2017/02/17 14:56:10]

Done.

+    Node* const make_type_error = LoadContextElement(
+        LoadNativeContext(context), Context::MAKE_TYPE_ERROR_INDEX);
+    return CallJS(CodeFactory::Call(isolate()), context, make_type_error,
+                  UndefinedConstant(), SmiConstant(message), args...);
+  }
+
  protected:
   void DescriptorLookup(Node* unique_name, Node* descriptors, Node* bitfield3,
                         Label* if_found, Variable* var_name_index,