Revert r20974: Unify and simplify the FastCloneShallowArrayStub

src/code-stubs-hydrogen.cc

Index: src/code-stubs-hydrogen.cc
diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc
index 342e3176e53adf90ef99eca849e614284227a82e..68c9cd5d5992b3550460d402c1e18d28c9bc4071 100644
--- a/src/code-stubs-hydrogen.cc
+++ b/src/code-stubs-hydrogen.cc
@@ -150,9 +150,9 @@ bool CodeStubGraphBuilderBase::BuildGraph() {
   bool runtime_stack_params = descriptor_->stack_parameter_count_.is_valid();
   HInstruction* stack_parameter_count = NULL;
   for (int i = 0; i < param_count; ++i) {
-    Representation r = descriptor_->register_param_representations_ == NULL
-        ? Representation::Tagged()
-        : descriptor_->register_param_representations_[i];
+    Representation r = descriptor_->IsParameterCountRegister(i)
+        ? Representation::Integer32()
+        : Representation::Tagged();
     HParameter* param = Add<HParameter>(i, HParameter::REGISTER_PARAMETER, r);
     start_environment->Bind(i, param);
     parameters_[i] = param;
@@ -353,6 +353,8 @@ HValue* CodeStubGraphBuilder<FastCloneShallowArrayStub>::BuildCodeStub() {
   Factory* factory = isolate()->factory();
   HValue* undefined = graph()->GetConstantUndefined();
   AllocationSiteMode alloc_site_mode = casted_stub()->allocation_site_mode();
+  FastCloneShallowArrayStub::Mode mode = casted_stub()->mode();
+  int length = casted_stub()->length();
 
   HInstruction* allocation_site = Add<HLoadKeyed>(GetParameter(0),
                                                   GetParameter(1),
@@ -367,40 +369,46 @@ HValue* CodeStubGraphBuilder<FastCloneShallowArrayStub>::BuildCodeStub() {
       AllocationSite::kTransitionInfoOffset);
   HInstruction* boilerplate = Add<HLoadNamedField>(
       allocation_site, static_cast<HValue*>(NULL), access);
-  HValue* elements = AddLoadElements(boilerplate);
-  HValue* capacity = AddLoadFixedArrayLength(elements);
-  IfBuilder zero_capacity(this);
-  zero_capacity.If<HCompareNumericAndBranch>(capacity, graph()->GetConstant0(),
-                                           Token::EQ);
-  zero_capacity.Then();
-  Push(BuildCloneShallowArrayEmpty(boilerplate,
-                                   allocation_site,
-                                   alloc_site_mode));
-  zero_capacity.Else();
-  IfBuilder if_fixed_cow(this);
-  if_fixed_cow.If<HCompareMap>(elements, factory->fixed_cow_array_map());
-  if_fixed_cow.Then();
-  Push(BuildCloneShallowArrayCow(boilerplate,
-                                 allocation_site,
-                                 alloc_site_mode,
-                                 FAST_ELEMENTS));
-  if_fixed_cow.Else();
-  IfBuilder if_fixed(this);
-  if_fixed.If<HCompareMap>(elements, factory->fixed_array_map());
-  if_fixed.Then();
-  Push(BuildCloneShallowArrayNonEmpty(boilerplate,
-                                      allocation_site,
-                                      alloc_site_mode,
-                                      FAST_ELEMENTS));
-
-  if_fixed.Else();
-  Push(BuildCloneShallowArrayNonEmpty(boilerplate,
-                                      allocation_site,
-                                      alloc_site_mode,
-                                      FAST_DOUBLE_ELEMENTS));
-  if_fixed.End();
-  if_fixed_cow.End();
-  zero_capacity.End();
+  HValue* push_value;
+  if (mode == FastCloneShallowArrayStub::CLONE_ANY_ELEMENTS) {
+    HValue* elements = AddLoadElements(boilerplate);
+
+    IfBuilder if_fixed_cow(this);
+    if_fixed_cow.If<HCompareMap>(elements, factory->fixed_cow_array_map());
+    if_fixed_cow.Then();
+    push_value = BuildCloneShallowArray(boilerplate,
+                                        allocation_site,
+                                        alloc_site_mode,
+                                        FAST_ELEMENTS,
+                                        0/*copy-on-write*/);
+    environment()->Push(push_value);
+    if_fixed_cow.Else();
+
+    IfBuilder if_fixed(this);
+    if_fixed.If<HCompareMap>(elements, factory->fixed_array_map());
+    if_fixed.Then();
+    push_value = BuildCloneShallowArray(boilerplate,
+                                        allocation_site,
+                                        alloc_site_mode,
+                                        FAST_ELEMENTS,
+                                        length);
+    environment()->Push(push_value);
+    if_fixed.Else();
+    push_value = BuildCloneShallowArray(boilerplate,
+                                        allocation_site,
+                                        alloc_site_mode,
+                                        FAST_DOUBLE_ELEMENTS,
+                                        length);
+    environment()->Push(push_value);
+  } else {
+    ElementsKind elements_kind = casted_stub()->ComputeElementsKind();
+    push_value = BuildCloneShallowArray(boilerplate,
+                                        allocation_site,
+                                        alloc_site_mode,
+                                        elements_kind,
+                                        length);
+    environment()->Push(push_value);
+  }
 
   checker.ElseDeopt("Uninitialized boilerplate literals");
   checker.End();