[Turbofan] Implement super calls with spread bytecode in assembly code.

src/runtime/runtime-array.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/code-stubs.h"
 #include "src/conversions-inl.h"
 #include "src/elements.h"
@@ skipping 630 matching lines @@
     Handle<JSFunction> spread_iterable_function = isolate->spread_iterable();
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
         isolate, spread,
         Execution::Call(isolate, spread_iterable_function,
                         isolate->factory()->undefined_value(), 1, &spread));
   }
 
   return *spread;
 }
 
+RUNTIME_FUNCTION(Runtime_SpreadIterablePrepareFixed) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(1, args.length());
+  CONVERT_ARG_HANDLE_CHECKED(Object, spread, 0);
+
+  // Iterate over the spread if we need to.
+  if (spread->IterationHasObservableEffects()) {
+    Handle<JSFunction> spread_iterable_function = isolate->spread_iterable();
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+        isolate, spread,
+        Execution::Call(isolate, spread_iterable_function,
+                        isolate->factory()->undefined_value(), 1, &spread));
+  }
+  // Return the backing store fixed array.
+  Handle<JSArray> spread_array = Handle<JSArray>::cast(spread);
+  uint32_t spread_length;
+  CHECK(spread_array->length()->ToArrayIndex(&spread_length));
+
+  FixedArrayBase* a = spread_array->elements();
+  a->set_length(spread_length);
+  return a;
+}
+
 }  // namespace internal
 }  // namespace v8