[Atomics] code stubs for atomic operations

src/runtime/runtime-atomics.cc

Index: src/runtime/runtime-atomics.cc
diff --git a/src/runtime/runtime-atomics.cc b/src/runtime/runtime-atomics.cc
index 94d98d4ffaf77a46e4aec1cb088bd55b36e406e4..ef181349e0531a6e4ca7c4c0290c86a0cc385619 100644
--- a/src/runtime/runtime-atomics.cc
+++ b/src/runtime/runtime-atomics.cc
@@ -216,13 +216,6 @@ inline Object* DoCompareExchange(Isolate* isolate, void* buffer, size_t index,
 
 
 template <typename T>
-inline Object* DoLoad(Isolate* isolate, void* buffer, size_t index) {
-  T result = LoadSeqCst(static_cast<T*>(buffer) + index);
-  return ToObject(isolate, result);
-}
-
-
-template <typename T>
 inline Object* DoStore(Isolate* isolate, void* buffer, size_t index,
                        Handle<Object> obj) {
   T value = FromObject<T>(obj);
@@ -401,31 +394,6 @@ RUNTIME_FUNCTION(Runtime_AtomicsCompareExchange) {
 
 
 RUNTIME_FUNCTION(Runtime_AtomicsLoad) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 2);
-  CONVERT_ARG_HANDLE_CHECKED(JSTypedArray, sta, 0);
-  CONVERT_SIZE_ARG_CHECKED(index, 1);
-  RUNTIME_ASSERT(sta->GetBuffer()->is_shared());
-  RUNTIME_ASSERT(index < NumberToSize(isolate, sta->length()));
-
-  uint8_t* source = static_cast<uint8_t*>(sta->GetBuffer()->backing_store()) +
-                    NumberToSize(isolate, sta->byte_offset());
-
-  switch (sta->type()) {
-#define TYPED_ARRAY_CASE(Type, typeName, TYPE, ctype, size) \
-  case kExternal##Type##Array:                              \
-    return DoLoad<ctype>(isolate, source, index);
-
-    INTEGER_TYPED_ARRAYS(TYPED_ARRAY_CASE)
-#undef TYPED_ARRAY_CASE
-
-    case kExternalUint8ClampedArray:
-      return DoLoad<uint8_t>(isolate, source, index);
-
-    default:
-      break;
-  }
-
   UNREACHABLE();
   return isolate->heap()->undefined_value();
 }