HaloArray: Add aliasing methods

Author: jpsamaroo

src/memory-spaces.jl

@@ -322,8 +322,11 @@ struct CombinedAliasing <: AbstractAliasing
 end
 function memory_spans(ca::CombinedAliasing)
     # FIXME: Don't hardcode CPURAMMemorySpace
-    all_spans = MemorySpan{CPURAMMemorySpace}[]
-    for sub_a in ca.sub_ainfos
+    if length(ca.sub_ainfos) == 0
+        return MemorySpan{CPURAMMemorySpace}[]
+    end
+    all_spans = memory_spans(ca.sub_ainfos[1])
+    for sub_a in ca.sub_ainfos[2:end]
         append!(all_spans, memory_spans(sub_a))
     end
     return all_spans

src/utils/haloarray.jl

@@ -99,4 +99,22 @@ Adapt.adapt_structure(to, H::Dagger.HaloArray) =
     HaloArray(Adapt.adapt(to, H.center),
               Adapt.adapt.(Ref(to), H.edges),
               Adapt.adapt.(Ref(to), H.corners),
-              H.halo_width)
+              H.halo_width)
+
+function aliasing(A::HaloArray)
+    return CombinedAliasing([aliasing(A.center), aliasing(A.edges), aliasing(A.corners)])
+end
+memory_space(A::HaloArray) = memory_space(A.center)
+function move_rewrap(cache::AliasedObjectCache, from_proc::Processor, to_proc::Processor, from_space::MemorySpace, to_space::MemorySpace, A::HaloArray)
+    center_chunk = rewrap_aliased_object!(cache, from_proc, to_proc, from_space, to_space, A.center)
+    edge_chunks = ntuple(i->rewrap_aliased_object!(cache, from_proc, to_proc, from_space, to_space, A.edges[i]), length(A.edges))
+    corner_chunks = ntuple(i->rewrap_aliased_object!(cache, from_proc, to_proc, from_space, to_space, A.corners[i]), length(A.corners))
+    halo_width = A.halo_width
+    to_w = root_worker_id(to_proc)
+    return remotecall_fetch(to_w, from_proc, to_proc, from_space, to_space, center_chunk, edge_chunks, corner_chunks, halo_width) do from_proc, to_proc, from_space, to_space, center_chunk, edge_chunks, corner_chunks, halo_width
+        center_new = move(from_proc, to_proc, center_chunk)
+        edges_new = ntuple(i->move(from_proc, to_proc, edge_chunks[i]), length(edge_chunks))
+        corners_new = ntuple(i->move(from_proc, to_proc, corner_chunks[i]), length(corner_chunks))
+        return tochunk(HaloArray(center_new, edges_new, corners_new, halo_width), to_proc)
+    end
+end