Implement tracking and optimizations of packed arrays

src/x64/builtins-x64.cc

Index: src/x64/builtins-x64.cc
diff --git a/src/x64/builtins-x64.cc b/src/x64/builtins-x64.cc
index 4e037ff465f1e5b2ff1e3050520028276d5b23af..0af0a434772602fbdb104c77f18e24e2d1813357 100644
--- a/src/x64/builtins-x64.cc
+++ b/src/x64/builtins-x64.cc
@@ -977,7 +977,7 @@ static void AllocateEmptyJSArray(MacroAssembler* masm,
   const int initial_capacity = JSArray::kPreallocatedArrayElements;
   STATIC_ASSERT(initial_capacity >= 0);
 
-  __ LoadInitialArrayMap(array_function, scratch2, scratch1);
+  __ LoadInitialArrayMap(array_function, scratch2, scratch1, false);
 
   // Allocate the JSArray object together with space for a fixed array with the
   // requested elements.
@@ -1076,7 +1076,8 @@ static void AllocateJSArray(MacroAssembler* masm,
                             Register scratch,
                             bool fill_with_hole,
                             Label* gc_required) {
-  __ LoadInitialArrayMap(array_function, scratch, elements_array);
+  __ LoadInitialArrayMap(array_function, scratch,
+                         elements_array, fill_with_hole);
 
   if (FLAG_debug_code) {  // Assert that array size is not zero.
     __ testq(array_size, array_size);
@@ -1303,10 +1304,10 @@ static void ArrayNativeCode(MacroAssembler* masm,
   __ jmp(call_generic_code);
 
   __ bind(&not_double);
-  // Transition FAST_SMI_ONLY_ELEMENTS to FAST_ELEMENTS.
+  // Transition FAST_SMI_ELEMENTS to FAST_ELEMENTS.
   // rbx: JSArray
   __ movq(r11, FieldOperand(rbx, HeapObject::kMapOffset));
-  __ LoadTransitionedArrayMapConditional(FAST_SMI_ONLY_ELEMENTS,
+  __ LoadTransitionedArrayMapConditional(FAST_SMI_ELEMENTS,
                                          FAST_ELEMENTS,
                                          r11,
                                          kScratchRegister,