Implement tracking and optimizations of packed arrays

src/objects-printer.cc

Index: src/objects-printer.cc
diff --git a/src/objects-printer.cc b/src/objects-printer.cc
index 7d6ef67a30780135544660dd7cc1d90f9032b299..30b1cc9e118a2d3d3c6a81324dcaf666dce96780 100644
--- a/src/objects-printer.cc
+++ b/src/objects-printer.cc
@@ -318,7 +318,9 @@ void JSObject::PrintElements(FILE* out) {
   // Don't call GetElementsKind, its validation code can cause the printer to
   // fail when debugging.
   switch (map()->elements_kind()) {
-    case FAST_SMI_ONLY_ELEMENTS:
+    case FAST_HOLEY_SMI_ELEMENTS:
+    case FAST_SMI_ELEMENTS:
+    case FAST_HOLEY_ELEMENTS:
     case FAST_ELEMENTS: {
       // Print in array notation for non-sparse arrays.
       FixedArray* p = FixedArray::cast(elements());
@@ -329,16 +331,19 @@ void JSObject::PrintElements(FILE* out) {
       }
       break;
     }
+    case FAST_HOLEY_DOUBLE_ELEMENTS:
     case FAST_DOUBLE_ELEMENTS: {
       // Print in array notation for non-sparse arrays.
-      FixedDoubleArray* p = FixedDoubleArray::cast(elements());
-      for (int i = 0; i < p->length(); i++) {
-        if (p->is_the_hole(i)) {
-          PrintF(out, "   %d: <the hole>", i);
-        } else {
-          PrintF(out, "   %d: %g", i, p->get_scalar(i));
+      if (elements()->length() != 0) {
+        FixedDoubleArray* p = FixedDoubleArray::cast(elements());
+        for (int i = 0; i < p->length(); i++) {
+          if (p->is_the_hole(i)) {
+            PrintF(out, "   %d: <the hole>", i);
+          } else {
+            PrintF(out, "   %d: %g", i, p->get_scalar(i));
+          }
+          PrintF(out, "\n");
         }
-        PrintF(out, "\n");
       }
       break;
     }