diff --git a/src/hb-aat-layout-kerx-table.hh b/src/hb-aat-layout-kerx-table.hh
index fbeb35b0c..33f626c6f 100644
--- a/src/hb-aat-layout-kerx-table.hh
+++ b/src/hb-aat-layout-kerx-table.hh
@@ -928,9 +928,9 @@ struct KerxTable
 
       /* See comment in sanitize() for conditional here. */
       if (i < count - 1)
-	c->sanitizer.set_object (*st);
+	c->sanitizer.set_object (st);
       else
-	c->sanitizer.reset_object ();
+	c->sanitizer.set_object ();
 
       ret |= st->dispatch (c);
 
@@ -943,7 +943,7 @@ struct KerxTable
       st = &StructAfter<SubTable> (*st);
       c->set_lookup_index (c->lookup_index + 1);
     }
-    c->sanitizer.reset_object ();
+    c->sanitizer.set_object ();
 
     return ret;
   }
@@ -962,7 +962,7 @@ struct KerxTable
     unsigned int count = thiz()->tableCount;
     for (unsigned int i = 0; i < count; i++)
     {
-      c->reset_object ();
+      c->set_object ();
       if (unlikely (!st->u.header.sanitize (c)))
 	return_trace (false);
       /* OpenType kern table has 2-byte subtable lengths.  That's limiting.
@@ -973,13 +973,13 @@ struct KerxTable
        * have multiple subtables.  To handle such fonts, we just ignore
        * the length for the last subtable. */
       if (i < count - 1)
-	c->set_object (*st);
+	c->set_object (st);
 
       if (unlikely (!st->sanitize (c)))
 	return_trace (false);
       st = &StructAfter<SubTable> (*st);
     }
-    c->reset_object ();
+    c->set_object ();
 
     return_trace (true);
   }
diff --git a/src/hb-aat-layout-morx-table.hh b/src/hb-aat-layout-morx-table.hh
index dc406f59f..bc7c3c37b 100644
--- a/src/hb-aat-layout-morx-table.hh
+++ b/src/hb-aat-layout-morx-table.hh
@@ -1026,7 +1026,7 @@ struct Chain
       if (reverse)
         c->buffer->reverse ();
 
-      c->sanitizer.set_object (*subtable);
+      c->sanitizer.set_object (subtable);
 
       subtable->dispatch (c);
 
@@ -1041,7 +1041,7 @@ struct Chain
       subtable = &StructAfter<ChainSubtable<Types> > (*subtable);
       c->set_lookup_index (c->lookup_index + 1);
     }
-    c->sanitizer.reset_object ();
+    c->sanitizer.set_object ();
   }
 
   inline unsigned int get_size (void) const { return length; }
@@ -1061,15 +1061,15 @@ struct Chain
     unsigned int count = subtableCount;
     for (unsigned int i = 0; i < count; i++)
     {
-      c->reset_object ();
+      c->set_object ();
       if (unlikely (!c->check_struct (subtable)))
 	return_trace (false);
-      c->set_object (*subtable);
+      c->set_object (subtable);
       if (!subtable->sanitize (c))
 	return_trace (false);
       subtable = &StructAfter<ChainSubtable<Types> > (*subtable);
     }
-    c->reset_object ();
+    c->set_object ();
 
     return_trace (true);
   }
diff --git a/src/hb-machinery.hh b/src/hb-machinery.hh
index edef54053..7457a099e 100644
--- a/src/hb-machinery.hh
+++ b/src/hb-machinery.hh
@@ -259,13 +259,20 @@ struct hb_sanitize_context_t :
 
   inline void set_max_ops (int max_ops_) { max_ops = max_ops_; }
 
-  template <typename T>
-  inline void set_object (const T& obj)
-  {
-    reset_object ();
+  struct dummy_get_size_t
+  { inline unsigned int get_size (void) const { return 0; } };
 
-    const char *obj_start = (const char *) &obj;
-    const char *obj_end = (const char *) &obj + obj.get_size ();
+  template <typename T = dummy_get_size_t>
+  inline void set_object (const T *obj = nullptr)
+  {
+    this->start = this->blob->data;
+    this->end = this->start + this->blob->length;
+    assert (this->start <= this->end); /* Must not overflow. */
+
+    if (!obj) return;
+
+    const char *obj_start = (const char *) obj;
+    const char *obj_end = (const char *) obj + obj->get_size ();
     assert (obj_start <= obj_end); /* Must not overflow. */
 
     if (unlikely (obj_end < this->start || this->end < obj_start))
@@ -277,16 +284,9 @@ struct hb_sanitize_context_t :
     }
   }
 
-  inline void reset_object (void)
-  {
-    this->start = this->blob->data;
-    this->end = this->start + this->blob->length;
-    assert (this->start <= this->end); /* Must not overflow. */
-  }
-
   inline void start_processing (void)
   {
-    reset_object ();
+    set_object ();
     this->max_ops = MAX ((unsigned int) (this->end - this->start) * HB_SANITIZE_MAX_OPS_FACTOR,
 			 (unsigned) HB_SANITIZE_MAX_OPS_MIN);
     this->edit_count = 0;