if (!maybe->ToObject(&writable)) return maybe;
backing_store = FixedArray::cast(writable);
}
- int length = IsJSArray()
+ uint32_t length = static_cast<uint32_t>(
+ IsJSArray()
? Smi::cast(JSArray::cast(this)->length())->value()
- : backing_store->length();
- if (index < static_cast<uint32_t>(length)) {
+ : backing_store->length());
+ if (index < length) {
backing_store->set_the_hole(index);
+ // If an old space backing store is larger than a certain size and
+ // has too few used values, normalize it.
+ // To avoid doing the check on every delete we require at least
+ // one adjacent hole to the value being deleted.
+ Object* hole = heap->the_hole_value();
+ const int kMinLengthForSparsenessCheck = 64;
+ if (backing_store->length() >= kMinLengthForSparsenessCheck &&
+ !heap->InNewSpace(backing_store) &&
+ ((index > 0 && backing_store->get(index - 1) == hole) ||
+ (index + 1 < length && backing_store->get(index + 1) == hole))) {
+ int num_used = 0;
+ for (int i = 0; i < backing_store->length(); ++i) {
+ if (backing_store->get(i) != hole) ++num_used;
+ // Bail out early if more than 1/4 is used.
+ if (4 * num_used > backing_store->length()) break;
+ }
+ if (4 * num_used <= backing_store->length()) {
+ MaybeObject* result = NormalizeElements();
+ if (result->IsFailure()) return result;
+ }
+ }
}
return heap->true_value();
}