Cleanup adding elements and in particular dictionary elements

src/elements.cc

Index: src/elements.cc
diff --git a/src/elements.cc b/src/elements.cc
index 672b04198bc716ec5fbd550aa803f030070932cc..ea368847e0eed25886e45da00376ad2c6f3d762d 100644
--- a/src/elements.cc
+++ b/src/elements.cc
@@ -989,11 +989,12 @@ class FastElementsAccessor
     if (length == 0) return;  // nothing to do!
     DisallowHeapAllocation no_gc;
     Handle<BackingStore> backing_store = Handle<BackingStore>::cast(elements);
-    for (int i = 0; i < length; i++) {
-      DCHECK((!IsFastSmiElementsKind(KindTraits::Kind) ||
-              BackingStore::get(backing_store, i)->IsSmi()) ||
-             (IsFastHoleyElementsKind(KindTraits::Kind) ==
-              backing_store->is_the_hole(i)));
+    if (IsFastSmiElementsKind(KindTraits::Kind)) {

[Jakob Kummerow, 2015/06/23 12:05:14]

I wonder if it would be useful to validate fast object elements too. At least
two things could be checked: 
(1) for FAST_ELEMENTS, there are no holes; 
(2) holey or not, all non-holes are either Smis or valid heap objects (roughly
"o->IsHeapObject() && HeapObject::cast(o)->map()->IsMap()")

Can leave it as is for now, though. Adding more checks would make pretty much
every single Debug test run slower, and currently we have no reason to suspect
bugs in this area.

[Toon Verwaest, 2015/06/23 12:28:17]

True. Can investigate later. Probably it makes more sense to just check the
stored value ...

+      for (int i = 0; i < length; i++) {
+        DCHECK(BackingStore::get(backing_store, i)->IsSmi() ||
+               (IsFastHoleyElementsKind(KindTraits::Kind) &&
+                backing_store->is_the_hole(i)));
+      }
     }
 #endif
   }
@@ -1345,13 +1346,8 @@ class DictionaryElementsAccessor
       dict->ElementsRemoved(removed_entries);
     }
 
-    if (length <= Smi::kMaxValue) {
-      array->set_length(Smi::FromInt(length));
-    } else {
-      Isolate* isolate = array->GetIsolate();
-      Handle<Object> length_obj = isolate->factory()->NewNumberFromUint(length);
-      array->set_length(*length_obj);
-    }
+    Handle<Object> length_obj = isolate->factory()->NewNumberFromUint(length);
+    array->set_length(*length_obj);
   }
 
   static void DeleteCommon(Handle<JSObject> obj, uint32_t key,