[STF] Refactor data_place to use polymorphic design

cudax/include/cuda/experimental/__stf/allocators/pooled_allocator.cuh

@@ -96,7 +96,7 @@ public:
     }
 
     ::std::ptrdiff_t sz = nentries * block_size;
-    base                = root_allocator.allocate(ctx, place, sz, prereqs);
+    base                = root_allocator.allocate(ctx, this->place, sz, prereqs);
     assert(sz > 0);
     assert(base);
 

cudax/include/cuda/experimental/__stf/internal/logical_data.cuh

@@ -1467,8 +1467,7 @@ public:
         continue;
       }
 
-      // TODO THIS MAY BE A BUG: do we care about managed devices or host?
-      const auto memory_node = data_place::device(static_cast<int>(n - 2));
+      const auto memory_node = from_index(n);
       // Skip the target memory node in this step
       if (memory_node == target_memory_node)
       {
@@ -1732,7 +1731,9 @@ inline void reserved::logical_data_untyped_impl::erase()
 
       data_instance& ref_instance  = get_data_instance(ref_id);
       const data_place& ref_dplace = ref_instance.get_dplace();
-      auto e                       = ref_dplace.affine_exec_place();
+      _CCCL_ASSERT(!ref_dplace.is_affine() && !ref_dplace.is_invalid(),
+                   "ref_dplace must be resolved to a concrete place before erase");
+      auto e = ref_dplace.affine_exec_place();
       l.reconstruct_after_redux(ctx, ref_id, e, wb_prereqs);
 
       h_state.current_mode = access_mode::none;

cudax/include/cuda/experimental/__stf/internal/task.cuh

@@ -441,6 +441,9 @@ void dep_allocate(
 {
   auto& inst = d.get_data_instance(instance_id);
 
+  _CCCL_ASSERT(!dplace.is_affine() && !dplace.is_invalid(),
+               "dep_allocate requires a concrete data_place (resolved upstream in acquire)");
+
   /*
    * DATA LAZY ALLOCATION
    */
@@ -471,6 +474,8 @@ void dep_allocate(
         inst.allocated_size = s;
         inst.set_allocated(true);
         inst.reclaimable = true;
+        _CCCL_ASSERT(!inst.get_dplace().is_affine() && !inst.get_dplace().is_invalid(),
+                     "instance dplace must be concrete after allocation");
         break;
       }