The proposal has not seemed to progress for a while, and there is
a open issue about module imports which breaks HTML integration.
While we could probably make an AD-HOC change to fix that issue,
it is deep enough in the JS engine that I am not particularly
keen on making that change.
Until other browsers begin to make positive signals about shipping
ShadowRealms, let's remove our implementation for now.
There is still some cleanup that can be done with regard to the
HTML integration, but there are a few more items that need to be
untangled there.
Replace the OwnPtr<IndexedPropertyStorage> indirection with inline
indexed element storage directly on Object. This eliminates virtual
dispatch and reduces indirection for indexed property access.
The new system uses three storage kinds tracked by IndexedStorageKind:
- Packed: Dense array, no holes. Elements stored in a malloced Value*
array with capacity header (same layout as named properties).
- Holey: Dense array with possible holes marked by empty sentinel.
Same physical layout as Packed.
- Dictionary: Sparse storage using GenericIndexedPropertyStorage,
type-punned into the m_indexed_elements pointer.
Transitions: None->Packed->Holey->Dictionary (mostly monotonic).
Dictionary mode triggers on non-default attributes or sparse arrays.
Object keeps the same 48-byte size since m_indexed_elements (8 bytes)
replaces IndexedProperties (8 bytes), and the storage kind + array
size fit in existing padding alongside m_flags.
The asm interpreter benefits from one fewer indirection: it now reads
the element pointer and array size directly from Object fields instead
of chasing through OwnPtr -> IndexedPropertyStorage -> Vector.
Removes: IndexedProperties, SimpleIndexedPropertyStorage,
IndexedPropertyStorage, IndexedPropertyIterator.
Keeps: GenericIndexedPropertyStorage (for Dictionary mode).
Since it does more than removing the quotes by escaping the string too
It makes sense to change the name of the flag to something more close
to what it's really doing.
It's generally considered a security issue to use non-format string
literals. We would likely just crash in practice, but let's avoid the
issue altogether.
The special empty value (that we use for array holes, Optional<Value>
when empty and a few other other placeholder/sentinel tasks) still
exists, but you now create one via JS::js_special_empty_value() and
check for it with Value::is_special_empty_value().
The main idea here is to make it very unlikely to accidentally create an
unexpected special empty value.
This also includes a stubbed Temporal.Duration.prototype.
Until we have re-implemented Temporal.PlainDate/ZonedDateTime, some of
Temporal.Duration.compare (and its invoked AOs) are left unimplemented.
Our Temporal implementation is woefully out of date. The spec has been
so vastly rewritten that it is unfortunately not practical to update our
implementation in-place. Even just removing Temporal objects that were
removed from the spec, or updating any of the simpler remaining objects,
has proven to be a mess in previous attempts.
So, this removes our Temporal implementation. AOs used by other specs
are left intact.
