Revert r20974: Unify and simplify the FastCloneShallowArrayStub

src/arm/full-codegen-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1803 matching lines @@
   if (has_fast_elements && !FLAG_allocation_site_pretenuring) {
     // If the only customer of allocation sites is transitioning, then
     // we can turn it off if we don't have anywhere else to transition to.
     allocation_site_mode = DONT_TRACK_ALLOCATION_SITE;
   }
 
   __ ldr(r3, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
   __ ldr(r3, FieldMemOperand(r3, JSFunction::kLiteralsOffset));
   __ mov(r2, Operand(Smi::FromInt(expr->literal_index())));
   __ mov(r1, 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, r1, r2);
+  } else if (expr->depth() > 1 || Serializer::enabled() ||
+             length > FastCloneShallowArrayStub::kMaximumClonedLength) {
     __ mov(r0, Operand(Smi::FromInt(flags)));
     __ Push(r3, r2, r1, r0);
     __ 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);
   }
 
   bool result_saved = false;  // Is the result saved to the stack?
 
   // Emit code to evaluate all the non-constant subexpressions and to store
   // them into the newly cloned array.
   for (int i = 0; i < length; i++) {
     Expression* subexpr = subexprs->at(i);
     // If the subexpression is a literal or a simple materialized literal it
@@ skipping 3075 matching lines @@
 
   ASSERT(interrupt_address ==
          isolate->builtins()->OsrAfterStackCheck()->entry());
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM