Implement tracking and optimizations of packed arrays

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index 974269e5dc9eea249c4030885879e293a9001eaa..fd7d957040682ef1de87066737aa8fe6ceb1d09b 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -1659,7 +1659,8 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
   ASSERT_EQ(2, constant_elements->length());
   ElementsKind constant_elements_kind =
       static_cast<ElementsKind>(Smi::cast(constant_elements->get(0))->value());
-  bool has_constant_fast_elements = constant_elements_kind == FAST_ELEMENTS;
+  bool has_constant_fast_elements =
+      IsFastObjectElementsKind(constant_elements_kind);
   Handle<FixedArrayBase> constant_elements_values(
       FixedArrayBase::cast(constant_elements->get(1)));
 
@@ -1670,7 +1671,7 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
   Heap* heap = isolate()->heap();
   if (has_constant_fast_elements &&
       constant_elements_values->map() == heap->fixed_cow_array_map()) {
-    // If the elements are already FAST_ELEMENTS, the boilerplate cannot
+    // If the elements are already FAST_*_ELEMENTS, the boilerplate cannot
     // change, so it's possible to specialize the stub in advance.
     __ IncrementCounter(isolate()->counters()->cow_arrays_created_stub(), 1);
     FastCloneShallowArrayStub stub(
@@ -1682,10 +1683,9 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
   } else if (length > FastCloneShallowArrayStub::kMaximumClonedLength) {
     __ CallRuntime(Runtime::kCreateArrayLiteralShallow, 3);
   } else {
-    ASSERT(constant_elements_kind == FAST_ELEMENTS ||
-           constant_elements_kind == FAST_SMI_ONLY_ELEMENTS ||
+    ASSERT(IsFastSmiOrObjectElementsKind(constant_elements_kind) ||
            FLAG_smi_only_arrays);
-    // If the elements are already FAST_ELEMENTS, the boilerplate cannot
+    // If the elements are already FAST_*_ELEMENTS, the boilerplate cannot
     // change, so it's possible to specialize the stub in advance.
     FastCloneShallowArrayStub::Mode mode = has_constant_fast_elements
         ? FastCloneShallowArrayStub::CLONE_ELEMENTS
@@ -1713,9 +1713,9 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
     }
     VisitForAccumulatorValue(subexpr);
 
-    if (constant_elements_kind == FAST_ELEMENTS) {
-      // Fast-case array literal with ElementsKind of FAST_ELEMENTS, they cannot
-      // transition and don't need to call the runtime stub.
+    if (IsFastObjectElementsKind(constant_elements_kind)) {
+      // Fast-case array literal with ElementsKind of FAST_*_ELEMENTS, they
+      // cannot transition and don't need to call the runtime stub.
       int offset = FixedArray::kHeaderSize + (i * kPointerSize);
       __ movq(rbx, Operand(rsp, 0));  // Copy of array literal.
       __ movq(rbx, FieldOperand(rbx, JSObject::kElementsOffset));