[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 dcce0afe5c9b127883027c5b61674d1e272bff51..70110455ed56f7ec8d26f65271ff4d0fe1ae6ffa 100644
--- a/src/interface-descriptors.h
+++ b/src/interface-descriptors.h
@@ -90,7 +90,8 @@ class PlatformInterfaceDescriptor;
   V(InterpreterDispatch)                      \
   V(InterpreterPushArgsAndCall)               \
   V(InterpreterPushArgsAndConstruct)          \
-  V(InterpreterCEntry)
+  V(InterpreterCEntry)                        \
+  V(AtomicsLoad)
 
 class CallInterfaceDescriptorData {
  public:
@@ -822,6 +823,11 @@ class InterpreterCEntryDescriptor : public CallInterfaceDescriptor {
   DECLARE_DESCRIPTOR(InterpreterCEntryDescriptor, CallInterfaceDescriptor)
 };
 
+class AtomicsLoadDescriptor : public CallInterfaceDescriptor {
+ public:
+  DECLARE_DESCRIPTOR(AtomicsLoadDescriptor, CallInterfaceDescriptor)
+};
+
 #undef DECLARE_DESCRIPTOR_WITH_BASE
 #undef DECLARE_DESCRIPTOR
 #undef DECLARE_DESCRIPTOR_WITH_CUSTOM_FUNCTION_TYPE