src/Pure/Tools/build_process.scala

       val job =
         synchronized {
           val (numa_node, state1) = _state.numa_next(build_context.numa_nodes)
           val node_info = Build_Job.Node_Info(build_context.hostname, numa_node)
           val job =
-            new Build_Job.Build_Session(progress, verbose, session_background, session_heaps,
+            new Build_Job.Session_Job(progress, verbose, session_background, session_heaps,
               store, do_store, resources, build_context.session_setup,
               build_deps.sources_shasum(session_name), input_heaps, node_info)
           _state = state1.add_running(session_name, job)
           job
         }