DispatcherMapField was templated on the device adapter but it
actually doesn't need to be, only BasicInvoke and subsequent
methods need to be templated on the device.
Previously, all Fetch objects received an Invocation object in their
Load and Store methods. The point of this was that it allowed the Fetch
to get data from any of the execution objects. However, every Fetch
either just got data directly from its associated execution object or
else used a secondary execution object (the input domain) to get indices
into their own execution object.
This left two potential areas for improvement. First, pulling data out
of the Invocation object was unnecessarily complicated. It would be much
nicer to get data directly from the associated execution object. Second,
when getting index information from the input domain, it was often the
case that extra computations were necessary (particularly on structured
cell sets). There was no way to share the index information among
Fetches, and therefore the computations were replicated.
This change removes the Invocation from the Fetch Load and Store.
Instead, it passes the associated execution object and a new object type
called the ThreadIndices. The ThreadIndices are customized for the input
domain and therefore have all the information needed for a redirected
lookup. It is also a thread-local object so it can cache computed
indices and save on computation time.
Previously, DispatcherBase had an ivar to determine whether to use the
numInstances passed on the stack or to use a 3D range held in a
different ivar. This change allows either a 1D range or 3D range to be
passed on the stack, which I expect to be closer to how we we handle
this when 3D ranges are fully supported.
This also fixes a bug introduced with commit
fdac208acbfa47b613d899a36cefc32a01e8f0a8 where the Use3DSchedule ivar
was not set correctly in UnitTestDispatcherBase.
This is a simple version of a dispatcher, but an important one.
Note that there is an issue brought up with UnitTestWorkletMapField in
that there needs to be better ways to specify worklet argument types.
