Only allow non-null pointers in the WeakSet
https://bugs.webkit.org/show_bug.cgi?id=85119
Reviewed by Darin Adler.
../JavaScriptCore:
This is a step toward more efficient finalization.
No clients put non-pointers (JSValues) into Weak<T> and PassWeak<T>.
Some clients put null pointers into Weak<T> and PassWeak<T>, but this is
more efficient and straight-forward to model with a null in the Weak<T>
or PassWeak<T> instead of allocating a WeakImpl just to hold null.
(JSC): Removed the Unknown (JSValue) type of weak pointer because it's
unused now.
(PassWeak): Don't provide a default initializer for our JSCell* argument.
This feature was only used in one place, and it was a bug.
(JSC::::get): Don't check for a null stored inside our WeakImpl: that's
not allowed anymore.
(JSC::PassWeak::PassWeak): Handle null as a null WeakImpl instead of
allocating a WeakImpl and storing null into it.
(Weak):
(JSC::::Weak): Same changes as in PassWeak<T>.
(JSC::WeakBlock::visitLiveWeakImpls):
(JSC::WeakBlock::visitDeadWeakImpls): Only non-null cells are valid in
the WeakSet now, so no need to check for non-cells and null cell pointers.
(JSC::WeakImpl::WeakImpl): Only non-null cells are valid in the WeakSet
now, so ASSERT that.
../WebCore:
- bridge/jsc/BridgeJSC.cpp:
(JSC::Bindings::Instance::Instance): Don't allocate a WeakImpl just to
store null. This was needless, and is now a compile error. Instead,
rely on the default constructor, which will produce a cheap null.
