diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index 8a257ff5dd..4f29d03f84 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -1388,6 +1388,12 @@ public:
 
 	void globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to);
 
+	/* Can be accessed only in process() context, and only after
+	 * Session::process() has returned.
+	 */
+
+	ProcessedRanges processed_ranges;
+
 protected:
 	friend class AudioEngine;
 	void set_block_size (pframes_t nframes);
diff --git a/libs/ardour/session_process.cc b/libs/ardour/session_process.cc
index e555a8b1e1..3b492d3811 100644
--- a/libs/ardour/session_process.cc
+++ b/libs/ardour/session_process.cc
@@ -117,6 +117,16 @@ Session::process (pframes_t nframes)
 		io_graph_chain.reset (); /* drop reference */
 	}
 
+	/* set up processed_ranges with the default values.
+
+	   This will be updated by ::process_without_events(),
+	   ::process_with_events() and ::locate()
+	*/
+
+	processed_ranges.start[0] = _transport_sample;
+	processed_ranges.end[0] = _transport_sample;
+	processed_ranges.cnt = 1;
+
 	(this->*process_function) (nframes);
 
 	io_graph_chain = _io_graph_chain[1];
@@ -188,6 +198,8 @@ Session::process (pframes_t nframes)
 		/* don't bother with a message */
 	}
 
+	processed_ranges.end[processed_ranges.cnt - 1] = _transport_sample;
+
 	SendFeedback (); /* EMIT SIGNAL */
 }
 
@@ -657,6 +669,8 @@ Session::process_with_events (pframes_t nframes)
 
 	} /* implicit release of route lock */
 
+	processed_ranges.end[processed_ranges.cnt - 1] = _transport_sample;
+
 	clear_active_cue ();
 
 	if (session_needs_butler) {
@@ -750,6 +764,8 @@ Session::process_without_events (pframes_t nframes)
 		DEBUG_TRACE (DEBUG::Butler, "p-without-events: session needs butler, call it\n");
 		_butler->summon ();
 	}
+
+	processed_ranges.end[processed_ranges.cnt - 1] = _transport_sample;
 }
 
 /** Process callback used when the auditioner is active.
diff --git a/libs/ardour/session_transport.cc b/libs/ardour/session_transport.cc
index 379b3b983d..ff5131ee4c 100644
--- a/libs/ardour/session_transport.cc
+++ b/libs/ardour/session_transport.cc
@@ -296,6 +296,12 @@ Session::locate (samplepos_t target_sample, bool for_loop_end, bool force, bool
 		send_mmc_locate (_transport_sample);
 	}
 
+	if (for_loop_end) {
+		processed_ranges.end[0] = existing;
+		processed_ranges.start[1] = _transport_sample;
+		processed_ranges.cnt = 2;
+	}
+
 	_last_roll_location = _last_roll_or_reversal_location =  _transport_sample;
 
 	Located (); /* EMIT SIGNAL */