diff --git a/src/compiler.c b/src/compiler.c
index 9832cdb..1493586 100644
--- a/src/compiler.c
+++ b/src/compiler.c
@@ -3,6 +3,7 @@
 #include "tac.h"
 #include "term.h"
 #include "termlist.h"
+#include "label.h"
 #include "memory.h"
 #include "system.h"
 #include "knowledge.h"
@@ -20,19 +21,6 @@
 static System sys;
 static Tac tac_root;
 
-/*
- * Structure to store label information
- */
-struct labelinfo
-{
-    Term label;
-    Term protocol;
-    Term sendrole;
-    Term readrole;
-};
-
-typedef struct labelinfo Labelinfo;
-
 /*
  * Declaration from system.c
  */
@@ -391,6 +379,7 @@ commEvent (int event, Tac tc)
   Term claimbig = NULL;
   int n = 0;
   Tac trip;
+  Labelinfo linfo;
 
   /* Construct label, if any */
   if (tc->t1.sym == NULL)
@@ -417,6 +406,20 @@ commEvent (int event, Tac tc)
 	    makeTermTuple (thisProtocol->nameterm, label);
 	}
     }
+  /**
+   * We now know the label. Find the corresponding labelinfo bit or make a new one
+   */
+  linfo = label_find (sys->labellist, label);
+  if (linfo == NULL)
+    {
+      /* Not found, make a new one */
+      linfo = label_create (label, thisProtocol);
+      sys->labellist = list_append (sys->labellist, linfo);
+    }
+
+  /**
+   * Parse the specific event type
+   */
   trip = tc->t2.tac;
   switch (event)
     {
@@ -434,11 +437,24 @@ commEvent (int event, Tac tc)
 
       if (event == SEND)
 	{
+	  /* set sendrole */
+	  if (linfo->sendrole != NULL)
+	      error ("Label defined twice for sendrole!");
+	  linfo->sendrole = fromrole;
+
 	  /* set keylevels based on send events */
 	  term_set_keylevels (fromrole);
 	  term_set_keylevels (torole);
 	  term_set_keylevels (msg);
 	}
+      else
+	{
+	  // READ
+	  /* set readrole */
+	  if (linfo->readrole != NULL)
+	      error ("Label defined twice for readrole!");
+	  linfo->readrole = torole;
+	}
 
       break;
     case CLAIM:
@@ -518,6 +534,7 @@ commEvent (int event, Tac tc)
       cl->complete = 0;
       cl->failed = 0;
       cl->prec = NULL;
+      cl->roles = NULL;
       cl->next = sys->claimlist;
       sys->claimlist = cl;
 
@@ -905,6 +922,30 @@ compute_role_variables (const System sys, Protocol p, Role r)
     }
 }
 
+//! Compute term list of rolenames involved in a given term list of labels
+Termlist 
+compute_label_roles (Termlist labels)
+{
+  Termlist roles;
+
+  roles = NULL;
+  while (labels != NULL)
+    {
+      Labelinfo linfo;
+
+      linfo = label_find (sys->labellist, labels->term);
+#ifdef DEBUG
+      if (linfo == NULL)
+	  error ("Label in prec list not found in label info list");
+#endif
+      roles = termlistAddNew (roles, linfo->sendrole);
+      roles = termlistAddNew (roles, linfo->readrole);
+
+      labels = labels->next;
+    }
+  return roles;
+}
+
 //! Compute prec() sets for each claim.
 /**
  * Generates two auxiliary structures. First, a table that contains
@@ -1180,6 +1221,12 @@ compute_prec_sets (const System sys)
 	    }
 	  r2++;
 	}
+      /**
+       * cl->prec is done, now we infer cl->roles
+       */
+
+      cl->roles = compute_label_roles (cl->prec);
+
       /**
        * ---------------------------
        * Distinguish types of claims
@@ -1268,9 +1315,21 @@ compute_prec_sets (const System sys)
 	}
       else
 	{
-	  // printf ("Preceding label set for r:%i, ev:%i = ", r1,ev1);
-	  // termlistPrint (cl->prec);
-	  // printf ("\n");
+#ifdef DEBUG
+	  if (DEBUGL (3))
+	    {
+	      Protocol p;
+
+	      printf ("Preceding label set for r:%i, ev:%i = ", r1,ev1);
+	      termlistPrint (cl->prec);
+	      printf (", involving roles ");
+	      termlistPrint (cl->roles);
+	      printf (", from protocol ");
+	      p = (Protocol) cl->protocol;
+	      termPrint (p->nameterm);
+	      printf ("\n");
+	    }
+#endif
 	}
 
       // Proceed to next claim
diff --git a/src/label.c b/src/label.c
index 8e4b3f6..9aa228b 100644
--- a/src/label.c
+++ b/src/label.c
@@ -5,8 +5,11 @@
 #include "memory.h"
 #include "term.h"
 #include "label.h"
+#include "list.h"
+#include "system.h"
 
-Labelinfo label_create (const Term label, const Term protocol)
+//! Create a new labelinfo node
+Labelinfo label_create (const Term label, const Protocol protocol)
 {
   Labelinfo li;
 
@@ -18,8 +21,35 @@ Labelinfo label_create (const Term label, const Term protocol)
   return li;
 }
 
+//! Destroy a labelinfo node
 void label_destroy (Labelinfo linfo)
 {
   memFree (linfo, sizeof (struct labelinfo));
 }
 
+//! Given a list of label infos, yield the correct one or NULL
+Labelinfo label_find (List labellist, const Term label)
+{
+  Labelinfo linfo;
+
+  int scan (void *data)
+    {
+      Labelinfo linfo_scan;
+
+      linfo_scan = (Labelinfo) data;
+      if (isTermEqual (label, linfo_scan->label))
+	{
+	  linfo = linfo_scan;
+	  return 0;
+	}
+      else
+	{
+	  return 1;
+	}
+    }
+
+  linfo = NULL;
+  list_iterate (labellist, scan);
+  return linfo;
+}
+
diff --git a/src/label.h b/src/label.h
index 71ed060..2f6b1fa 100644
--- a/src/label.h
+++ b/src/label.h
@@ -2,6 +2,8 @@
 #define LABEL
 
 #include "term.h"
+#include "list.h"
+#include "system.h"
 
 /*
  * Structure to store label information
@@ -16,7 +18,8 @@ struct labelinfo
 
 typedef struct labelinfo* Labelinfo;
 
-Labelinfo label_create (const Term label, const Term protocol);
+Labelinfo label_create (const Term label, const Protocol protocol);
 void label_destroy (Labelinfo linfo);
+Labelinfo label_find (List labellist, const Term label);
 
 #endif
diff --git a/src/role.h b/src/role.h
index bee51d8..777e14d 100644
--- a/src/role.h
+++ b/src/role.h
@@ -37,6 +37,8 @@ struct claimlist
   int ev;			//!< event index in role
   //! Preceding label list
   Termlist prec;
+  //! Roles that are involved (nameterms)
+  Termlist roles;
   //! Next node pointer or NULL for the last element of the function.
   struct claimlist *next;
 };
diff --git a/src/termlist.c b/src/termlist.c
index 7aa04d9..b674478 100644
--- a/src/termlist.c
+++ b/src/termlist.c
@@ -222,7 +222,7 @@ termlistAppend (const Termlist tl, const Term term)
 Termlist
 termlistAddNew (const Termlist tl, const Term t)
 {
-  if (inTermlist (tl, t))
+  if (t == NULL || inTermlist (tl, t))
     return tl;
   else
     return termlistAdd (tl, t);