Instead of attaching lookaheads and duplicating the rules being

reduced by a state, attach the lookaheads to the reductions.
* src/state.h (state_t): Remove the `lookaheads',
`lookaheads_rule' member.
(reductions_t): Add a `lookaheads' member.
Use a regular array for the `rules'.
* src/state.c (reductions_new): Initialize the lookaheads member
to 0.
(state_rule_lookaheads_print): Adjust.
* src/state.h, src/state.c (state_reductions_find): New.
* src/conflicts.c (resolve_sr_conflict, set_conflicts)
(count_rr_conflicts): Adjust.
* src/lalr.c (LArule): Remove.
(add_lookback_edge): Adjust.
(state_lookaheads_count): New.
(states_lookaheads_initialize): Merge into...
(initialize_LA): this.
(lalr_free): Adjust.
* src/main.c (main): Don't free nullable and derives too early: it
is used by --verbose.
* src/print.c, src/print_graph.c, src/tables.c: Adjust.

ChangeLog

@@ -1,3 +1,28 @@
+2002-08-01  Akim Demaille  <akim@epita.fr>
+
+	Instead of attaching lookaheads and duplicating the rules being
+	reduced by a state, attach the lookaheads to the reductions.
+
+	* src/state.h (state_t): Remove the `lookaheads',
+	`lookaheads_rule' member.
+	(reductions_t): Add a `lookaheads' member.
+	Use a regular array for the `rules'.
+	* src/state.c (reductions_new): Initialize the lookaheads member
+	to 0.
+	(state_rule_lookaheads_print): Adjust.
+	* src/state.h, src/state.c (state_reductions_find): New.
+	* src/conflicts.c (resolve_sr_conflict, set_conflicts)
+	(count_rr_conflicts): Adjust.
+	* src/lalr.c (LArule): Remove.
+	(add_lookback_edge): Adjust.
+	(state_lookaheads_count): New.
+	(states_lookaheads_initialize): Merge into...
+	(initialize_LA): this.
+	(lalr_free): Adjust.
+	* src/main.c (main): Don't free nullable and derives too early: it
+	is used by --verbose.
+	* src/print.c, src/print_graph.c, src/tables.c: Adjust.
+
 2002-08-01  Akim Demaille  <akim@epita.fr>
 
 	* src/derives.h, src/derives.c (derives): A `rule_t***' instead of

src/conflicts.c

@@ -175,14 +175,15 @@ flush_reduce (bitset lookaheads, int token)
 `------------------------------------------------------------------*/
 
 static void
-resolve_sr_conflict (state_t *state, int lookahead,
+resolve_sr_conflict (state_t *state, int ruleno,
 		     symbol_t **errs)
 {
   symbol_number_t i;
+  reductions_t *reds = state->reductions;
   /* Find the rule to reduce by to get precedence of reduction.  */
-  rule_t *redrule = state->lookaheads_rule[lookahead];
+  rule_t *redrule = reds->rules[ruleno];
   int redprec = redrule->prec->prec;
-  bitset lookaheads = state->lookaheads[lookahead];
+  bitset lookaheads = reds->lookaheads[ruleno];
   int nerrs = 0;
 
   for (i = 0; i < ntokens; i++)
@@ -259,6 +260,7 @@ set_conflicts (state_t *state, symbol_t **errs)
 {
   int i;
   transitions_t *transitions = state->transitions;
+  reductions_t *reds = state->reductions;
 
   if (state->consistent)
     return;
@@ -271,10 +273,9 @@ set_conflicts (state_t *state, symbol_t **errs)
   /* Loop over all rules which require lookahead in this state.  First
      check for shift-reduce conflict, and try to resolve using
      precedence.  */
-  for (i = 0; i < state->nlookaheads; ++i)
+  for (i = 0; i < reds->num; ++i)
-    if (state->lookaheads_rule[i]->prec
+    if (reds->rules[i]->prec && reds->rules[i]->prec->prec
-	&& state->lookaheads_rule[i]->prec->prec
+	&& !bitset_disjoint_p (reds->lookaheads[i], lookaheadset))
-	&& !bitset_disjoint_p (state->lookaheads[i], lookaheadset))
       {
 	resolve_sr_conflict (state, i, errs);
 	break;
@@ -282,12 +283,12 @@ set_conflicts (state_t *state, symbol_t **errs)
 
   /* Loop over all rules which require lookahead in this state.  Check
      for conflicts not resolved above.  */
-  for (i = 0; i < state->nlookaheads; ++i)
+  for (i = 0; i < reds->num; ++i)
     {
-      if (!bitset_disjoint_p (state->lookaheads[i], lookaheadset))
+      if (!bitset_disjoint_p (reds->lookaheads[i], lookaheadset))
 	conflicts[state->number] = 1;
 
-      bitset_or (lookaheadset, lookaheadset, state->lookaheads[i]);
+      bitset_or (lookaheadset, lookaheadset, reds->lookaheads[i]);
     }
 }
 
@@ -333,6 +334,7 @@ count_sr_conflicts (state_t *state)
   int i;
   int src_count = 0;
   transitions_t *transitions = state->transitions;
+  reductions_t *reds = state->reductions;
 
   if (!transitions)
     return 0;
@@ -343,8 +345,8 @@ count_sr_conflicts (state_t *state)
   FOR_EACH_SHIFT (transitions, i)
     bitset_set (shiftset, TRANSITION_SYMBOL (transitions, i));
 
-  for (i = 0; i < state->nlookaheads; ++i)
+  for (i = 0; i < reds->num; ++i)
-    bitset_or (lookaheadset, lookaheadset, state->lookaheads[i]);
+    bitset_or (lookaheadset, lookaheadset, reds->lookaheads[i]);
 
   bitset_and (lookaheadset, lookaheadset, shiftset);
 
@@ -365,17 +367,15 @@ static int
 count_rr_conflicts (state_t *state, int one_per_token)
 {
   int i;
+  reductions_t *reds = state->reductions;
   int rrc_count = 0;
 
-  if (state->nlookaheads < 2)
-    return 0;
-
   for (i = 0; i < ntokens; i++)
     {
       int count = 0;
       int j;
-      for (j = 0; j < state->nlookaheads; ++j)
+      for (j = 0; j < reds->num; ++j)
-	if (bitset_test (state->lookaheads[j], i))
+	if (bitset_test (reds->lookaheads[j], i))
 	  count++;
 
       if (count >= 2)
@@ -456,9 +456,10 @@ conflicts_output (FILE *out)
   for (i = 0; i < nstates; i++)
     {
       state_t *s = states[i];
+      reductions_t *reds = s->reductions;
       int j;
-      for (j = 0; j < s->reductions->num; ++j)
+      for (j = 0; j < reds->num; ++j)
-	used_rules[s->reductions->rules[j]->number] = TRUE;
+	used_rules[reds->rules[j]->number] = TRUE;
       if (conflicts[i])
 	{
 	  fprintf (out, _("State %d contains "), i);

src/lalr.c

@@ -52,16 +52,6 @@ typedef struct goto_list_s
 } goto_list_t;
 
 
-/* LARULE is a vector which records the rules that need lookahead in
-   various states.  The elements of LARULE that apply to state S are
-   those from LOOKAHEADS[S] through LOOKAHEADS[S+1]-1.
-
-   If LR is the length of LArule, then a number from 0 to LR-1 can
-   specify both a rule and a state where the rule might be applied.
-   */
-
-static rule_t **LArule = NULL;
-
 /* LA is a LR by NTOKENS matrix of bits.  LA[l, i] is 1 if the rule
    LArule[l] is applicable in the appropriate state when the next
    token is symbol i.  If LA[l, i] and LA[l, j] are both 1 for i != j,
@@ -81,29 +71,6 @@ static goto_list_t **lookback;
 
 
 
-static void
-initialize_LA (void)
-{
-  state_number_t i;
-  int j;
-  rule_t **np;
-
-  /* Avoid having to special case 0.  */
-  if (!nLA)
-    nLA = 1;
-
-  LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
-  LArule = XCALLOC (rule_t *, nLA);
-  lookback = XCALLOC (goto_list_t *, nLA);
-
-  np = LArule;
-  for (i = 0; i < nstates; i++)
-    if (!states[i]->consistent)
-      for (j = 0; j < states[i]->reductions->num; j++)
-	*np++ = states[i]->reductions->rules[j];
-}
-
-
 static void
 set_goto_map (void)
 {
@@ -246,19 +213,11 @@ initialize_F (void)
 static void
 add_lookback_edge (state_t *state, rule_t *rule, int gotono)
 {
-  int i;
+  int r = state_reduction_find (state, rule);
-  goto_list_t *sp;
+  goto_list_t *sp = XCALLOC (goto_list_t, 1);
-
+  sp->next = lookback[(state->reductions->lookaheads - LA) + r];
-  for (i = 0; i < state->nlookaheads; ++i)
-    if (state->lookaheads_rule[i] == rule)
-      break;
-
-  assert (state->lookaheads_rule[i] == rule);
-
-  sp = XCALLOC (goto_list_t, 1);
-  sp->next = lookback[(state->lookaheads - LA) + i];
   sp->value = gotono;
-  lookback[(state->lookaheads - LA) + i] = sp;
+  lookback[(state->reductions->lookaheads - LA) + r] = sp;
 }
 
 
@@ -365,24 +324,18 @@ compute_lookaheads (void)
 }
 
 
-/*-------------------------------------------------------------.
+/*---------------------------------------------------------------.
-| Count the number of lookaheads required for each state       |
+| Count the number of lookaheads required for STATE (NLOOKAHEADS |
-| (NLOOKAHEADS member).  Compute the total number of LA, NLA.  |
+| member).                                                       |
-`-------------------------------------------------------------*/
+`---------------------------------------------------------------*/
 
-static void
+static int
-states_lookaheads_count (void)
+state_lookaheads_count (state_t *state)
 {
-  state_number_t i;
-  nLA = 0;
-
-  /* Count   */
-  for (i = 0; i < nstates; i++)
-    {
   int k;
   int nlookaheads = 0;
-      reductions_t *rp = states[i]->reductions;
+  reductions_t *rp = state->reductions;
-      transitions_t *sp = states[i]->transitions;
+  transitions_t *sp = state->transitions;
 
   /* We need a lookahead either to distinguish different
      reductions (i.e., there are two or more), or to distinguish a
@@ -393,40 +346,50 @@ states_lookaheads_count (void)
 	  !TRANSITION_IS_DISABLED (sp, 0) && TRANSITION_IS_SHIFT (sp, 0)))
     nlookaheads += rp->num;
   else
-	states[i]->consistent = 1;
+    state->consistent = 1;
 
   for (k = 0; k < sp->num; k++)
     if (!TRANSITION_IS_DISABLED (sp, k) && TRANSITION_IS_ERROR (sp, k))
       {
-	    states[i]->consistent = 0;
+	state->consistent = 0;
 	break;
       }
 
-      states[i]->nlookaheads = nlookaheads;
+  return nlookaheads;
-      nLA += nlookaheads;
-    }
 }
 
 
-/*--------------------------------------.
+/*----------------------------------------------.
-| Initializing the lookaheads members.  |
+| Compute LA, NLA, and the lookaheads members.  |
-`--------------------------------------*/
+`----------------------------------------------*/
 
 static void
-states_lookaheads_initialize (void)
+initialize_LA (void)
 {
   state_number_t i;
-  bitsetv pLA = LA;
+  bitsetv pLA;
-  rule_t **pLArule = LArule;
 
-  /* Initialize the members LOOKAHEADS and LOOKAHEADS_RULE for each
+  /* Compute the total number of reductions requiring a lookahead.  */
-     state.  */
+  nLA = 0;
+  for (i = 0; i < nstates; i++)
+    nLA += state_lookaheads_count (states[i]);
+  /* Avoid having to special case 0.  */
+  if (!nLA)
+    nLA = 1;
+
+  pLA = LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
+  lookback = XCALLOC (goto_list_t *, nLA);
+
+  /* Initialize the members LOOKAHEADS for each state which reductions
+     require lookaheads.  */
   for (i = 0; i < nstates; i++)
     {
-      states[i]->lookaheads = pLA;
+      int count = state_lookaheads_count (states[i]);
-      states[i]->lookaheads_rule = pLArule;
+      if (count)
-      pLA += states[i]->nlookaheads;
+	{
-      pLArule += states[i]->nlookaheads;
+	  states[i]->reductions->lookaheads = pLA;
+	  pLA += count;
+	}
     }
 }
 
@@ -443,17 +406,25 @@ lookaheads_print (FILE *out)
   fprintf (out, "Lookaheads: BEGIN\n");
   for (i = 0; i < nstates; ++i)
     {
+      reductions_t *reds = states[i]->reductions;
       bitset_iterator iter;
+      int nlookaheads = 0;
+
+      if (reds->lookaheads)
+	for (k = 0; k < reds->num; ++k)
+	  if (reds->lookaheads[k])
+	    ++nlookaheads;
 
       fprintf (out, "State %d: %d lookaheads\n",
-	       i, states[i]->nlookaheads);
+	       i, nlookaheads);
 
-      for (j = 0; j < states[i]->nlookaheads; ++j)
+      if (reds->lookaheads)
-	BITSET_FOR_EACH (iter, states[i]->lookaheads[j], k, 0)
+	for (j = 0; j < reds->num; ++j)
+	  BITSET_FOR_EACH (iter, reds->lookaheads[j], k, 0)
 	  {
 	    fprintf (out, "   on %d (%s) -> rule %d\n",
 		     k, symbols[k]->tag,
-		   states[i]->lookaheads_rule[j]->number);
+		     reds->rules[j]->number);
 	  };
     }
   fprintf (out, "Lookaheads: END\n");
@@ -462,9 +433,7 @@ lookaheads_print (FILE *out)
 void
 lalr (void)
 {
-  states_lookaheads_count ();
   initialize_LA ();
-  states_lookaheads_initialize ();
   set_goto_map ();
   initialize_F ();
   build_relations ();
@@ -481,10 +450,6 @@ lalr_free (void)
 {
   state_number_t s;
   for (s = 0; s < nstates; ++s)
-    {
+    states[s]->reductions->lookaheads = NULL;
-      states[s]->lookaheads = NULL;
-      states[s]->lookaheads_rule = NULL;
-    }
   bitsetv_free (LA);
-  free (LArule);
 }

src/main.c

@@ -99,11 +99,6 @@ main (int argc, char *argv[])
   lalr ();
   timevar_pop (TV_LALR);
 
-  timevar_push (TV_FREE);
-  nullable_free ();
-  derives_free ();
-  timevar_pop (TV_FREE);
-
   /* Find and record any conflicts: places where one token of
      lookahead is not enough to disambiguate the parsing.  In file
      conflicts.  Also resolve s/r conflicts based on precedence
@@ -153,6 +148,8 @@ main (int argc, char *argv[])
   timevar_pop (TV_PARSER);
 
   timevar_push (TV_FREE);
+  nullable_free ();
+  derives_free ();
   tables_free ();
   states_free ();
   reduce_free ();

src/print.c

@@ -244,25 +244,25 @@ state_default_rule (state_t *state)
 	bitset_set (shiftset, errp->symbols[i]->number);
   }
 
-  for (i = 0; i < state->nlookaheads; ++i)
+  for (i = 0; i < redp->num; ++i)
     {
       int count = 0;
 
       /* How many non-masked lookaheads are there for this reduction?
 	 */
-      bitset_andn (lookaheadset, state->lookaheads[i], shiftset);
+      bitset_andn (lookaheadset, redp->lookaheads[i], shiftset);
       count = bitset_count (lookaheadset);
 
       if (count > cmax)
 	{
 	  cmax = count;
-	  default_rule = state->lookaheads_rule[i];
+	  default_rule = redp->rules[i];
 	}
 
       /* 3. And finally, each reduction is possibly masked by previous
 	 reductions (in R/R conflicts, we keep the first reductions).
 	 */
-      bitset_or (shiftset, shiftset, state->lookaheads[i]);
+      bitset_or (shiftset, shiftset, redp->lookaheads[i]);
     }
 
   return default_rule;
@@ -322,16 +322,18 @@ print_reductions (FILE *out, state_t *state)
   /* Compute the width of the lookaheads column.  */
   if (default_rule)
     width = strlen (_("$default"));
+
+  if (redp->lookaheads)
     for (i = 0; i < ntokens; i++)
       {
 	int count = bitset_test (shiftset, i);
 
-      for (j = 0; j < state->nlookaheads; ++j)
+	for (j = 0; j < redp->num; ++j)
-	if (bitset_test (state->lookaheads[j], i))
+	  if (bitset_test (redp->lookaheads[j], i))
 	    {
 	      if (count == 0)
 		{
-		if (state->lookaheads_rule[j] != default_rule)
+		  if (redp->rules[j] != default_rule)
 		    max_length (&width, symbols[i]->tag);
 		  count++;
 		}
@@ -350,20 +352,21 @@ print_reductions (FILE *out, state_t *state)
   width += 2;
 
   /* Report lookaheads (or $default) and reductions.  */
+  if (redp->lookaheads)
     for (i = 0; i < ntokens; i++)
       {
 	int defaulted = 0;
 	int count = bitset_test (shiftset, i);
 
-      for (j = 0; j < state->nlookaheads; ++j)
+	for (j = 0; j < redp->num; ++j)
-	if (bitset_test (state->lookaheads[j], i))
+	  if (bitset_test (redp->lookaheads[j], i))
 	    {
 	      if (count == 0)
 		{
-		if (state->lookaheads_rule[j] != default_rule)
+		  if (redp->rules[j] != default_rule)
 		    print_reduction (out, width,
 				     symbols[i]->tag,
-				   state->lookaheads_rule[j], TRUE);
+				     redp->rules[j], TRUE);
 		  else
 		    defaulted = 1;
 		  count++;
@@ -377,7 +380,7 @@ print_reductions (FILE *out, state_t *state)
 		  defaulted = 0;
 		  print_reduction (out, width,
 				   symbols[i]->tag,
-				 state->lookaheads_rule[j], FALSE);
+				   redp->rules[j], FALSE);
 		}
 	    }
       }

src/print_graph.c

@@ -86,28 +86,23 @@ print_core (struct obstack *oout, state_t *state)
 	obstack_fgrow1 (oout, " %s", symbols[*sp]->tag);
 
       /* Experimental feature: display the lookaheads. */
-      if ((report_flag & report_lookaheads)
+      if (report_flag & report_lookaheads)
-	  && state->nlookaheads)
+	{
+	  /* Find the reduction we are handling.  */
+	  reductions_t *reds = state->reductions;
+	  int redno = state_reduction_find (state, &rules[rule]);
+
+	  /* Print them if there are.  */
+	  if (reds->lookaheads && redno != -1)
 	    {
-	  int j, k;
 	      bitset_iterator biter;
-	  int nlookaheads = 0;
+	      int k;
-
+	      int not_first = 0;
-	  /* Look for lookaheads corresponding to this rule. */
+	      obstack_sgrow (oout, "[");
-	  for (j = 0; j < state->nlookaheads; ++j)
+	      BITSET_FOR_EACH (biter, reds->lookaheads[redno], k, 0)
-	    BITSET_FOR_EACH (biter, state->lookaheads[j], k, 0)
-	      if (state->lookaheads_rule[j]->number == rule)
-		nlookaheads++;
-
-	  if (nlookaheads)
-	    {
-	      obstack_sgrow (oout, "  [");
-	      for (j = 0; j < state->nlookaheads; ++j)
-		BITSET_FOR_EACH (biter, state->lookaheads[j], k, 0)
-		  if (state->lookaheads_rule[j]->number == rule)
 		obstack_fgrow2 (oout, "%s%s",
-				    symbols[k]->tag,
+				not_first++ ? ", " : "",
-				    --nlookaheads ? ", " : "");
+				symbols[k]->tag);
 	      obstack_sgrow (oout, "]");
 	    }
 	}

src/state.c

@@ -110,6 +110,7 @@ reductions_new (int num, rule_t **reductions)
   reductions_t *res = REDUCTIONS_ALLOC (num);
   res->num = num;
   memcpy (res->rules, reductions, num * sizeof (reductions[0]));
+  res->lookaheads = NULL;
   return res;
 }
 
@@ -196,6 +197,18 @@ state_reductions_set (state_t *state, int num, rule_t **reductions)
 }
 
 
+int
+state_reduction_find (state_t *state, rule_t *rule)
+{
+  int i;
+  reductions_t *reds = state->reductions;
+  for (i = 0; i < reds->num; ++i)
+    if (reds->rules[i] == rule)
+      return i;
+  return -1;
+}
+
+
 /*------------------------.
 | Set the errs of STATE.  |
 `------------------------*/
@@ -217,25 +230,21 @@ state_errs_set (state_t *state, int num, symbol_t **tokens)
 void
 state_rule_lookaheads_print (state_t *state, rule_t *rule, FILE *out)
 {
-  int j, k;
+  /* Find the reduction we are handling.  */
-  bitset_iterator biter;
+  reductions_t *reds = state->reductions;
-  int nlookaheads = 0;
+  int red = state_reduction_find (state, rule);
-  /* Count the number of lookaheads corresponding to this rule.  */
-  for (j = 0; j < state->nlookaheads; ++j)
-    BITSET_FOR_EACH (biter, state->lookaheads[j], k, 0)
-      if (state->lookaheads_rule[j] == rule)
-	nlookaheads++;
 
   /* Print them if there are.  */
-  if (nlookaheads)
+  if (reds->lookaheads && red != -1)
     {
+      bitset_iterator biter;
+      int k;
+      int not_first = 0;
       fprintf (out, "  [");
-      for (j = 0; j < state->nlookaheads; ++j)
+      BITSET_FOR_EACH (biter, reds->lookaheads[red], k, 0)
-	BITSET_FOR_EACH (biter, state->lookaheads[j], k, 0)
-	  if (state->lookaheads_rule[j] == rule)
 	fprintf (out, "%s%s",
-		     symbols[k]->tag,
+		 not_first++ ? ", " : "",
-		     --nlookaheads ? ", " : "");
+		 symbols[k]->tag);
       fprintf (out, "]");
     }
 }

src/state.h

@@ -82,7 +82,7 @@
 #ifndef STATE_H_
 # define STATE_H_
 
-# include "bitsetv.h"
+# include "bitset.h"
 
 
 /*-------------------.
@@ -178,6 +178,7 @@ errs_t *errs_new PARAMS ((int num, symbol_t **tokens));
 typedef struct reductions_s
 {
   short num;
+  bitset *lookaheads;
   rule_t *rules[1];
 } reductions_t;
 
@@ -198,17 +199,6 @@ struct state_s
   /* Nonzero if no lookahead is needed to decide what to do in state S.  */
   char consistent;
 
-  /* Used in LALR, not LR(0).
-
-     When a state is not consistent (there is an S/R or R/R conflict),
-     lookaheads are needed to enable the reductions.  NLOOKAHEADS is
-     the number of lookahead guarded reductions of the
-     LOOKAHEADS_RULE.  For each rule LOOKAHEADS_RULE[R], LOOKAHEADS[R]
-     is the bitset of the lookaheads enabling this reduction.  */
-  int nlookaheads;
-  bitsetv lookaheads;
-  rule_t **lookaheads_rule;
-
   /* If some conflicts were solved thanks to precedence/associativity,
      a human readable description of the resolution.  */
   const char *solved_conflicts;
@@ -234,6 +224,8 @@ void state_transitions_set PARAMS ((state_t *state,
 void state_reductions_set PARAMS ((state_t *state,
 				   int num, rule_t **reductions));
 
+int state_reduction_find PARAMS ((state_t *state, rule_t *rule));
+
 /* Set the errs of STATE.  */
 void state_errs_set PARAMS ((state_t *state,
 			     int num, symbol_t **errs));

src/tables.c

@@ -239,6 +239,7 @@ static void
 conflict_row (state_t *state)
 {
   int i, j;
+  reductions_t *reds = state->reductions;
 
   if (! glr_parser)
     return;
@@ -250,14 +251,13 @@ conflict_row (state_t *state)
 
 	/* Find all reductions for token J, and record all that do not
 	   match ACTROW[J].  */
-	for (i = 0; i < state->nlookaheads; i += 1)
+	for (i = 0; i < reds->num; i += 1)
-	  if (bitset_test (state->lookaheads[i], j)
+	  if (bitset_test (reds->lookaheads[i], j)
 	      && (actrow[j]
-		  != rule_number_as_item_number (state->lookaheads_rule[i]->number)))
+		  != rule_number_as_item_number (reds->rules[i]->number)))
 	    {
 	      assert (conflict_list_free > 0);
-	      conflict_list[conflict_list_cnt]
+	      conflict_list[conflict_list_cnt] = reds->rules[i]->number + 1;
-		= state->lookaheads_rule[i]->number + 1;
 	      conflict_list_cnt += 1;
 	      conflict_list_free -= 1;
 	    }
@@ -304,22 +304,23 @@ action_row (state_t *state)
   for (i = 0; i < ntokens; i++)
     actrow[i] = conflrow[i] = 0;
 
-  if (redp->num >= 1)
+  if (redp->lookaheads)
     {
       int j;
       bitset_iterator biter;
       /* loop over all the rules available here which require
-	 lookahead */
+	 lookahead (in reverse order to give precedence to the first
-      for (i = state->nlookaheads - 1; i >= 0; --i)
+	 rule) */
+      for (i = redp->num - 1; i >= 0; --i)
 	/* and find each token which the rule finds acceptable
 	   to come next */
-	BITSET_FOR_EACH (biter, state->lookaheads[i], j, 0)
+	BITSET_FOR_EACH (biter, redp->lookaheads[i], j, 0)
 	{
 	  /* and record this rule as the rule to use if that
 	     token follows.  */
 	  if (actrow[j] != 0)
 	    conflicted = conflrow[j] = 1;
-	  actrow[j] = rule_number_as_item_number (state->lookaheads_rule[i]->number);
+	  actrow[j] = rule_number_as_item_number (redp->rules[i]->number);
 	}
     }
 
@@ -359,10 +360,10 @@ action_row (state_t *state)
       else
 	{
 	  int max = 0;
-	  for (i = 0; i < state->nlookaheads; i++)
+	  for (i = 0; i < redp->num; i++)
 	    {
 	      int count = 0;
-	      rule_t *rule = state->lookaheads_rule[i];
+	      rule_t *rule = redp->rules[i];
 	      symbol_number_t j;
 
 	      for (j = 0; j < ntokens; j++)