Revert r20974: Unify and simplify the FastCloneShallowArrayStub

src/arm64/full-codegen-arm64.cc

Index: src/arm64/full-codegen-arm64.cc
diff --git a/src/arm64/full-codegen-arm64.cc b/src/arm64/full-codegen-arm64.cc
index e6b57ea8bd62dbb5d0f26e290e5ae6ea3dbc619e..2099fde186898ae49305d47dfaa83667b7fbbeca 100644
--- a/src/arm64/full-codegen-arm64.cc
+++ b/src/arm64/full-codegen-arm64.cc
@@ -1824,12 +1824,35 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
   __ Ldr(x3, FieldMemOperand(x3, JSFunction::kLiteralsOffset));
   __ Mov(x2, Smi::FromInt(expr->literal_index()));
   __ Mov(x1, Operand(constant_elements));
-  if (expr->depth() > 1) {
+  if (has_fast_elements && constant_elements_values->map() ==
+      isolate()->heap()->fixed_cow_array_map()) {
+    FastCloneShallowArrayStub stub(
+        isolate(),
+        FastCloneShallowArrayStub::COPY_ON_WRITE_ELEMENTS,
+        allocation_site_mode,
+        length);
+    __ CallStub(&stub);
+    __ IncrementCounter(
+        isolate()->counters()->cow_arrays_created_stub(), 1, x10, x11);
+  } else if ((expr->depth() > 1) || Serializer::enabled() ||
+             length > FastCloneShallowArrayStub::kMaximumClonedLength) {
     __ Mov(x0, Smi::FromInt(flags));
     __ Push(x3, x2, x1, x0);
     __ CallRuntime(Runtime::kHiddenCreateArrayLiteral, 4);
   } else {
-    FastCloneShallowArrayStub stub(isolate(), allocation_site_mode);
+    ASSERT(IsFastSmiOrObjectElementsKind(constant_elements_kind) ||
+           FLAG_smi_only_arrays);
+    FastCloneShallowArrayStub::Mode mode =
+        FastCloneShallowArrayStub::CLONE_ANY_ELEMENTS;
+
+    if (has_fast_elements) {
+      mode = FastCloneShallowArrayStub::CLONE_ELEMENTS;
+    }
+
+    FastCloneShallowArrayStub stub(isolate(),
+                                   mode,
+                                   allocation_site_mode,
+                                   length);
     __ CallStub(&stub);
   }