Reland r20974: Unify and simplify the FastCloneShallowArrayStub

src/mips/full-codegen-mips.cc

 // Copyright 2012 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 "v8.h"
 
 #if V8_TARGET_ARCH_MIPS
 
 // Note on Mips implementation:
 //
@@ skipping 1787 matching lines @@
     // 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;
   }
 
   __ mov(a0, result_register());
   __ lw(a3, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
   __ lw(a3, FieldMemOperand(a3, JSFunction::kLiteralsOffset));
   __ li(a2, Operand(Smi::FromInt(expr->literal_index())));
   __ li(a1, Operand(constant_elements));
-  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, a1, a2);
-  } else if (expr->depth() > 1 || Serializer::enabled(isolate()) ||
-             length > FastCloneShallowArrayStub::kMaximumClonedLength) {
+  if (expr->depth() > 1) {
     __ li(a0, Operand(Smi::FromInt(flags)));
     __ Push(a3, a2, a1, a0);
     __ CallRuntime(Runtime::kHiddenCreateArrayLiteral, 4);
   } else {
     ASSERT(IsFastSmiOrObjectElementsKind(constant_elements_kind) ||
            FLAG_smi_only_arrays);
     FastCloneShallowArrayStub::Mode mode =
         FastCloneShallowArrayStub::CLONE_ANY_ELEMENTS;
 
     if (has_fast_elements) {
@@ skipping 3043 matching lines @@
       Assembler::target_address_at(pc_immediate_load_address)) ==
          reinterpret_cast<uint32_t>(
              isolate->builtins()->OsrAfterStackCheck()->entry()));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS