--- a/src/hotspot/share/gc/shenandoah/shenandoahCollectionSet.hpp	Sat Apr 20 15:55:07 2019 +0800
+++ b/src/hotspot/share/gc/shenandoah/shenandoahCollectionSet.hpp	Wed Apr 24 11:39:56 2019 +0200
@@ -88,6 +88,9 @@
   void clear();
 
 private:
+  jbyte* map_address() const {
+    return _cset_map;
+  }
   jbyte* biased_map_address() const {
     return _biased_cset_map;
   }

--- a/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	Sat Apr 20 15:55:07 2019 +0800
+++ b/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	Wed Apr 24 11:39:56 2019 +0200
@@ -537,6 +537,15 @@
                p2i(reserved_region().start()),
                p2i(reserved_region().end()));
 
+  ShenandoahCollectionSet* cset = collection_set();
+  st->print_cr("Collection set:");
+  if (cset != NULL) {
+    st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address()));
+    st->print_cr(" - map (biased):  " PTR_FORMAT, p2i(cset->biased_map_address()));
+  } else {
+    st->print_cr(" (NULL)");
+  }
+
   st->cr();
   MetaspaceUtils::print_on(st);