[stubs] Introduce CSA::OptimalParameterMode(), TagParameter() and UntagParameter().

src/builtins/builtins-internal.cc

 // Copyright 2016 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/builtins/builtins.h"
 #include "src/builtins/builtins-utils.h"
 #include "src/interface-descriptors.h"
 #include "src/macro-assembler.h"
 
 namespace v8 {
@@ skipping 46 matching lines @@
     CodeStubAssembler* assembler) {
   typedef CodeStubAssembler::Label Label;
   typedef compiler::Node Node;
   typedef CopyFastSmiOrObjectElementsDescriptor Descriptor;
 
   Node* object = assembler->Parameter(Descriptor::kObject);
 
   // Load the {object}s elements.
   Node* source = assembler->LoadObjectField(object, JSObject::kElementsOffset);
 
-  CodeStubAssembler::ParameterMode mode =
-      assembler->Is64() ? CodeStubAssembler::INTEGER_PARAMETERS
-                        : CodeStubAssembler::SMI_PARAMETERS;
-  Node* length = (mode == CodeStubAssembler::INTEGER_PARAMETERS)
-                     ? assembler->LoadAndUntagFixedArrayBaseLength(source)
-                     : assembler->LoadFixedArrayBaseLength(source);
+  CodeStubAssembler::ParameterMode mode = assembler->OptimalParameterMode();
+  Node* length = assembler->UntagParameter(
+      assembler->LoadFixedArrayBaseLength(source), mode);
 
   // Check if we can allocate in new space.
   ElementsKind kind = FAST_ELEMENTS;
   int max_elements = FixedArrayBase::GetMaxLengthForNewSpaceAllocation(kind);
   Label if_newspace(assembler), if_oldspace(assembler);
   assembler->Branch(
       assembler->UintPtrLessThan(
           length, assembler->IntPtrOrSmiConstant(max_elements, mode)),
       &if_newspace, &if_oldspace);
 
@@ skipping 53 matching lines @@
       context, elements, FAST_ELEMENTS, key, &runtime);
   assembler->StoreObjectField(object, JSObject::kElementsOffset, elements);
   assembler->Return(elements);
 
   assembler->Bind(&runtime);
   assembler->TailCallRuntime(Runtime::kGrowArrayElements, context, object, key);
 }
 
 }  // namespace internal
 }  // namespace v8