With this change, we now have ~1200 CellAllocators across both LibJS and
LibWeb in a normal WebContent instance.
This gives us a minimum heap size of 4.7 MiB in the scenario where we
only have one cell allocated per type. Of course, in practice there will
be many more of each type, so the effective overhead is quite a bit
smaller than that in practice.
I left a few types unconverted to this mechanism because I got tired of
doing this. :^)
Stop worrying about tiny OOMs. Work towards #20449.
While going through these, I also changed the function signature in many
places where returning ThrowCompletionOr<T> is no longer necessary.
The compiler-generated copy constructor and copy assignment operator
already do the right thing (which is to simply copy the underlying
pointer).
The [Itanium C++ ABI][1] treats any class with non-trivial copy/move
constructors and destructors as non-trivial for the purposes of calls --
even if they are functionally identical to the compiler-generated ones.
If a class is non-trivial, it cannot be passed or returned in registers,
only via an invisible reference, which is worse for codegen. This commit
makes `{Nonnull,}GCPtr` trivial.
As the compiler can be sure that capturing a `GCPtr` by value has no
side effects, a few `-Wunused-lambda-capture` warnings had to be
addressed in LibWeb.
GCC seems to have a bug that prevents `ExceptionOr<Variant<GCPtr<T>>>`
from being implicitly constructed from `GCPtr<T>` after this change. A
non-invasive workaround is to explicitly construct the inner Variant
type.
[1]: https://itanium-cxx-abi.github.io/cxx-abi/abi.html#non-trivial
There are quite a few steps between a ReadableStream being created and
its controller being set. If GC occurs between those points, we will
have an empty Optional in ReadableStream::visit_edges. Seen on YouTube.
This is not documented yet, but the preferred style is getting both
upfront instead of inlining various kinds of calls in places that use
the realm and vm.
Note that as of this commit, there aren't any such throwers, and the
call site in Heap::allocate will drop exceptions on the floor. This
commit only serves to change the declaration of the overrides, make sure
they return an empty value, and to propagate OOM errors frm their base
initialize invocations.
This needs to happen before prototype/constructor intitialization can be
made lazy. Otherwise, GC could run during the C++ constructor and try to
collect the object currently being created.
These classes only needed Window to get at its realm. Pass a realm
directly to construct Crypto, Encoding, HRT, IntersectionObserver,
NavigationTiming, Page, RequestIdleCallback, Selection, Streams, URL,
and XML classes.
