[Atomics] code stubs for atomic operations

src/interface-descriptors.h

Index: src/interface-descriptors.h
diff --git a/src/interface-descriptors.h b/src/interface-descriptors.h
index 8a43ec13a66e47aa14aa0ce6535d0bbc8895979c..adfe9f5cda0edc43fef1303b9f34bc2a5d17cf40 100644
--- a/src/interface-descriptors.h
+++ b/src/interface-descriptors.h
@@ -78,7 +78,9 @@ class PlatformInterfaceDescriptor;
   V(GrowArrayElements)                        \
   V(InterpreterPushArgsAndCall)               \
   V(InterpreterPushArgsAndConstruct)          \
-  V(InterpreterCEntry)
+  V(InterpreterCEntry)                        \
+  V(AtomicsLoad)                              \
+  V(Builtin)
 
 
 class CallInterfaceDescriptorData {
@@ -785,6 +787,17 @@ class InterpreterCEntryDescriptor : public CallInterfaceDescriptor {
 };
 
 
+class AtomicsLoadDescriptor : public CallInterfaceDescriptor {
+ public:
+  DECLARE_DESCRIPTOR(AtomicsLoadDescriptor, CallInterfaceDescriptor)
+};
+
+
+class BuiltinDescriptor : public CallInterfaceDescriptor {
+ public:
+  DECLARE_DESCRIPTOR(BuiltinDescriptor, CallInterfaceDescriptor)
+};
+
 #undef DECLARE_DESCRIPTOR