This introduces a new MUST_UPCALL macro that expands to
[[clang::annotate("must_upcall")]] on Clang. When placed on a virtual
function, the Clang plugin will verify that all overrides call their
base class implementation.
This generalizes the existing Base::visit_edges() check to work with
any annotated virtual function. The first use is Cell::visit_edges(),
but this can be applied to other functions that require upcalls.
The plugin checks for calls via either Base:: (the common typedef
pattern) or the explicit parent class name.
Add a clang plugin check that flags GC::Cell subclasses (and their
base classes within the Cell hierarchy) that have destructors with
non-trivial bodies. Such logic should use Cell::finalize() instead.
Add GC_ALLOW_CELL_DESTRUCTOR annotation macro for opting out in
exceptional cases (currently only JS::Object).
This prevents us from accidentally adding code in destructors that
runs after something we're pointing to may have been destroyed.
(This could become a problem when the garbage collector sweeps
objects in an unfortunate order.)
This new check uncovered a handful of bugs which are then also fixed
in this commit. :^)
When passing a Vector<JS::Value> to the MarkingVisitor, we were
iterating over the vector and visiting one value at a time. This led
to a very inefficient way of building up the GC's work queue.
By adding a new visit_impl() virtual to Cell::Visitor, we can now
grow the work queue capacity once, and then add without incrementally
growing the storage.
Instead of checking if every single cell overrides the "must survive GC"
virtual, we can make this a HeapBlock level thing.
This avoids almost an entire GC heap traversal during the mark phase.
In our process architecture, there's only ever one JS::VM per process.
This allows us to have a VM::the() singleton getter that optimizes
down to a single global access everywhere.
Seeing 1-2% speed-up on all JS benchmarks from this.
Add the proper annotations for the Cell and Cell::Visitor classes to be
visible in Swift. This lets us remove some OpaquePointer shinangians in
the Swift bindings.
This patch adds a workaround for a Swift issue where boolean bitfields
with getters and setters in SWIFT_UNSAFE_REFERENCE types are improperly
imported, causing an ICE.
Previously, all `GC::Cell` derived classes were Weakable. Marking only
those classes that require this functionality as Weakable allows us to
reduce the memory footprint of some frequently used classes.
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
