Add lib/subpipe.c.

[bison.git] / src / lalr.c

diff --git a/src/lalr.c b/src/lalr.c
index 0b26925580c370a826d098425ee17b26fff61a76..2c0c942aeb216ab26c958efa11b616a5c0753de3 100644 (file)
--- a/src/lalr.c
+++ b/src/lalr.c
@@ -1,5 +1,6 @@
 /* Compute look-ahead criteria for bison,
 /* Compute look-ahead criteria for bison,

-   Copyright 1984, 1986, 1989, 2000, 2001  Free Software Foundation, Inc.
+   Copyright (C) 1984, 1986, 1989, 2000, 2001, 2002
+   Free Software Foundation, Inc.

 
    This file is part of Bison, the GNU Compiler Compiler.
 
 
    This file is part of Bison, the GNU Compiler Compiler.
 


@@ -24,267 +25,104 @@
    tokens they accept.  */
 
 #include "system.h"
    tokens they accept.  */
 
 #include "system.h"

-#include "types.h"
-#include "LR0.h"
+#include "bitset.h"
+#include "bitsetv.h"
+#include "relation.h"
+#include "quotearg.h"
+#include "symtab.h"

 #include "gram.h"
 #include "gram.h"

+#include "reader.h"
+#include "LR0.h"

 #include "complain.h"
 #include "lalr.h"
 #include "nullable.h"
 #include "derives.h"
 #include "getargs.h"
 
 #include "complain.h"
 #include "lalr.h"
 #include "nullable.h"
 #include "derives.h"
 #include "getargs.h"
 

-/* All the decorated states, indexed by the state number.  Warning:
-   there is a state_TABLE in LR0.c, but it is different and static.
-   */
-state_t **state_table = NULL;
-
-int tokensetsize;
-short *LAruleno;
-unsigned *LA;
-
-static int ngotos;
-short *goto_map;
-short *from_state;
-short *to_state;
-
-/* And for the famous F variable, which name is so descriptive that a
-   comment is hardly needed.  <grin>.  */
-static unsigned *F = NULL;
-#define F(Rule)  (F + (Rule) * tokensetsize)
-
-static short **includes;
-static shorts **lookback;
-
-
-/*---------------------------------------------------------------.
-| digraph & traverse.                                            |
-|                                                                |
-| The following variables are used as common storage between the |
-| two.                                                           |
-`---------------------------------------------------------------*/
-
-static short **R;
-static short *INDEX;
-static short *VERTICES;
-static int top;
-static int infinity;
+goto_number_t *goto_map = NULL;
+static goto_number_t ngotos = 0;
+state_number_t *from_state = NULL;
+state_number_t *to_state = NULL;

 
 

-static void
-traverse (int i)
+/* Linked list of goto numbers.  */
+typedef struct goto_list_s

 {
 {

-  int j;
-  size_t k;
-  int height;
-  size_t size = F (i + 1) - F(i);
-
-  VERTICES[++top] = i;
-  INDEX[i] = height = top;
-
-  if (R[i])
-    for (j = 0; R[i][j] >= 0; ++j)
-      {
-       if (INDEX[R[i][j]] == 0)
-         traverse (R[i][j]);
-
-       if (INDEX[i] > INDEX[R[i][j]])
-         INDEX[i] = INDEX[R[i][j]];
-
-       for (k = 0; k < size; ++k)
-         F (i)[k] |= F (R[i][j])[k];
-      }
-
-  if (INDEX[i] == height)
-    for (;;)
-      {
-       j = VERTICES[top--];
-       INDEX[j] = infinity;
+  struct goto_list_s *next;
+  goto_number_t value;
+} goto_list_t;

 
 

-       if (i == j)
-         break;
-
-       for (k = 0; k < size; ++k)
-         F (i)[k] = F (j)[k];
-      }
-}

 
 

+/* 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,
+   it is a conflict.  */

 
 

-static void
-digraph (short **relation)
-{
-  int i;
+static bitsetv LA = NULL;
+size_t nLA;

 
 

-  infinity = ngotos + 2;
-  INDEX = XCALLOC (short, ngotos + 1);
-  VERTICES = XCALLOC (short, ngotos + 1);
-  top = 0;

 
 

-  R = relation;
-
-  for (i = 0; i < ngotos; i++)
-    INDEX[i] = 0;
+/* And for the famous F variable, which name is so descriptive that a
+   comment is hardly needed.  <grin>.  */
+static bitsetv F = NULL;

 
 

-  for (i = 0; i < ngotos; i++)
-    if (INDEX[i] == 0 && R[i])
-      traverse (i);
+static goto_number_t **includes;
+static goto_list_t **lookback;

 
 

-  XFREE (INDEX);
-  XFREE (VERTICES);
-}

 
 
 
 

-/*--------------------.
-| Build STATE_TABLE.  |
-`--------------------*/

 
 static void
 
 static void

-set_state_table (void)
+set_goto_map (void)

 {
 {

-  /* NSTATES + 1 because lookahead for the pseudo state number NSTATES
-     might be used (see conflicts.c).  It is too opaque for me to
-     provide a probably less hacky implementation. --akim */
-  state_table = XCALLOC (state_t *, nstates + 1);
+  state_number_t state;
+  goto_number_t *temp_map;

 
 

-  {
-    state_t *sp;
-    for (sp = first_state; sp; sp = sp->next)
-      state_table[sp->number] = sp;
-  }
+  goto_map = XCALLOC (goto_number_t, nvars + 1) - ntokens;
+  temp_map = XCALLOC (goto_number_t, nvars + 1) - ntokens;

 
 

-  {
-    shifts *sp;
-    for (sp = first_shift; sp; sp = sp->next)
-      state_table[sp->number]->shifts = sp;
-  }
-
-  {
-    reductions *rp;
-    for (rp = first_reduction; rp; rp = rp->next)
-      state_table[rp->number]->reductions = rp;
-  }
+  ngotos = 0;
+  for (state = 0; state < nstates; ++state)
+    {
+      transitions_t *sp = states[state]->transitions;
+      int i;
+      for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
+       {
+         if (ngotos == GOTO_NUMBER_MAX)
+           fatal (_("too many gotos (max %d)"), GOTO_NUMBER_MAX);

 
 

-  /* Pessimization, but simplification of the code: make sure all the
-     states have a shifts, even if reduced to 0 shifts.  */
-  {
-    int i;
-    for (i = 0; i < nstates; i++)
-      if (!state_table[i]->shifts)
-       state_table[i]->shifts = shifts_new (0);
-  }
+         ngotos++;
+         goto_map[TRANSITION_SYMBOL (sp, i)]++;
+       }
+    }

 
 

-  /* Initializing the lookaheads members.  Please note that it must be
-     performed after having set some of the other members which are
-     used below.  Change with extreme caution.  */

   {
   {

+    int k = 0;

     int i;
     int i;

-    int count = 0;
-    for (i = 0; i < nstates; i++)
-      {
-       int k;
-       reductions *rp = state_table[i]->reductions;
-       shifts *sp = state_table[i]->shifts;
-
-       state_table[i]->lookaheads = count;
-
-       if (rp
-           && (rp->nreds > 1 || (sp->nshifts && SHIFT_IS_SHIFT (sp, 0))))
-         count += rp->nreds;
-       else
-         state_table[i]->consistent = 1;
-
-       for (k = 0; k < sp->nshifts; k++)
-         if (SHIFT_IS_ERROR (sp, k))
-           {
-             state_table[i]->consistent = 0;
-             break;
-           }
-      }
-
-    /* Seems to be needed by conflicts.c. */
-    state_table[nstates] = STATE_ALLOC (0);
-    state_table[nstates]->lookaheads = count;
-  }
-}
-
-
-static void
-initialize_LA (void)
-{
-  int i;
-  int j;
-  short *np;
-  reductions *rp;
-
-  size_t nLA = state_table[nstates]->lookaheads;
-  if (!nLA)
-    nLA = 1;
-
-  LA = XCALLOC (unsigned, nLA * tokensetsize);
-  LAruleno = XCALLOC (short, nLA);
-  lookback = XCALLOC (shorts *, nLA);
-
-  np = LAruleno;
-  for (i = 0; i < nstates; i++)
-    if (!state_table[i]->consistent)
-      if ((rp = state_table[i]->reductions))
-       for (j = 0; j < rp->nreds; j++)
-         *np++ = rp->rules[j];
-}
-
-
-static void
-set_goto_map (void)
-{
-  shifts *sp;
-  int i;
-  int symbol;
-  int k;
-  short *temp_map;
-  int state2;
-  int state1;
-
-  goto_map = XCALLOC (short, nvars + 1) - ntokens;
-  temp_map = XCALLOC (short, nvars + 1) - ntokens;
-
-  ngotos = 0;
-  for (sp = first_shift; sp; sp = sp->next)
-    for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
+    for (i = ntokens; i < nsyms; i++)

       {
       {

-       symbol = state_table[sp->shifts[i]]->accessing_symbol;
-
-       if (ngotos == MAXSHORT)
-         fatal (_("too many gotos (max %d)"), MAXSHORT);
-
-       ngotos++;
-       goto_map[symbol]++;
+       temp_map[i] = k;
+       k += goto_map[i];

       }
 
       }
 

-  k = 0;
-  for (i = ntokens; i < nsyms; i++)
-    {
-      temp_map[i] = k;
-      k += goto_map[i];
-    }
-
-  for (i = ntokens; i < nsyms; i++)
-    goto_map[i] = temp_map[i];
+    for (i = ntokens; i < nsyms; i++)
+      goto_map[i] = temp_map[i];

 
 

-  goto_map[nsyms] = ngotos;
-  temp_map[nsyms] = ngotos;
+    goto_map[nsyms] = ngotos;
+    temp_map[nsyms] = ngotos;
+  }

 
 

-  from_state = XCALLOC (short, ngotos);
-  to_state = XCALLOC (short, ngotos);
+  from_state = XCALLOC (state_number_t, ngotos);
+  to_state = XCALLOC (state_number_t, ngotos);

 
 

-  for (sp = first_shift; sp; sp = sp->next)
+  for (state = 0; state < nstates; ++state)

     {
     {

-      state1 = sp->number;
-      for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
+      transitions_t *sp = states[state]->transitions;
+      int i;
+      for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)

        {
        {

-         state2 = sp->shifts[i];
-         symbol = state_table[state2]->accessing_symbol;
-
-         k = temp_map[symbol]++;
-         from_state[k] = state1;
-         to_state[k] = state2;
+         int k = temp_map[TRANSITION_SYMBOL (sp, i)]++;
+         from_state[k] = state;
+         to_state[k] = sp->states[i]->number;

        }
     }
 
        }
     }
 


@@ -298,12 +136,12 @@ set_goto_map (void)
 `----------------------------------------------------------*/
 
 static int
 `----------------------------------------------------------*/
 
 static int

-map_goto (int state, int symbol)
+map_goto (state_number_t state, symbol_number_t symbol)

 {
   int high;
   int low;
   int middle;
 {
   int high;
   int low;
   int middle;

-  int s;
+  state_number_t s;

 
   low = goto_map[symbol];
   high = goto_map[symbol + 1] - 1;
 
   low = goto_map[symbol];
   high = goto_map[symbol + 1] - 1;


@@ -329,43 +167,40 @@ map_goto (int state, int symbol)
 static void
 initialize_F (void)
 {
 static void
 initialize_F (void)
 {

-  short **reads = XCALLOC (short *, ngotos);
-  short *edge = XCALLOC (short, ngotos + 1);
+  goto_number_t **reads = XCALLOC (goto_number_t *, ngotos);
+  goto_number_t *edge = XCALLOC (goto_number_t, ngotos + 1);

   int nedges = 0;
 
   int i;
 
   int nedges = 0;
 
   int i;
 

-  F = XCALLOC (unsigned, ngotos * tokensetsize);
+  F = bitsetv_create (ngotos, ntokens, BITSET_FIXED);

 
   for (i = 0; i < ngotos; i++)
     {
 
   for (i = 0; i < ngotos; i++)
     {

-      int stateno = to_state[i];
-      shifts *sp = state_table[stateno]->shifts;
+      state_number_t stateno = to_state[i];
+      transitions_t *sp = states[stateno]->transitions;

 
       int j;
 
       int j;

-      for (j = 0; j < sp->nshifts && SHIFT_IS_SHIFT (sp, j); j++)
-       {
-         int symbol = state_table[sp->shifts[j]]->accessing_symbol;
-         SETBIT (F (i), symbol);
-       }
+      FOR_EACH_SHIFT (sp, j)
+       bitset_set (F[i], TRANSITION_SYMBOL (sp, j));

 
 

-      for (; j < sp->nshifts; j++)
+      for (; j < sp->num; j++)

        {
        {

-         int symbol = state_table[sp->shifts[j]]->accessing_symbol;
+         symbol_number_t symbol = TRANSITION_SYMBOL (sp, j);

          if (nullable[symbol])
            edge[nedges++] = map_goto (stateno, symbol);
        }
 
       if (nedges)
        {
          if (nullable[symbol])
            edge[nedges++] = map_goto (stateno, symbol);
        }
 
       if (nedges)
        {

-         reads[i] = XCALLOC (short, nedges + 1);
-         shortcpy (reads[i], edge, nedges);
+         reads[i] = XCALLOC (goto_number_t, nedges + 1);
+         memcpy (reads[i], edge, nedges * sizeof (edge[0]));

          reads[i][nedges] = -1;
          nedges = 0;
        }
     }
 
          reads[i][nedges] = -1;
          nedges = 0;
        }
     }
 

-  digraph (reads);
+  relation_digraph (reads, ngotos, &F);

 
   for (i = 0; i < ngotos; i++)
     XFREE (reads[i]);
 
   for (i = 0; i < ngotos; i++)
     XFREE (reads[i]);


@@ -376,159 +211,49 @@ initialize_F (void)
 
 
 static void
 
 
 static void

-add_lookback_edge (int stateno, int ruleno, int gotono)
+add_lookback_edge (state_t *state, rule_t *rule, int gotono)

 {
 {

-  int i;
-  int k;
-  int found;
-  shorts *sp;
-
-  i = state_table[stateno]->lookaheads;
-  k = state_table[stateno + 1]->lookaheads;
-  found = 0;
-  while (!found && i < k)
-    {
-      if (LAruleno[i] == ruleno)
-       found = 1;
-      else
-       i++;
-    }
-
-  assert (found);
-
-  sp = XCALLOC (shorts, 1);
-  sp->next = lookback[i];
+  int r = state_reduction_find (state, rule);
+  goto_list_t *sp = XCALLOC (goto_list_t, 1);
+  sp->next = lookback[(state->reductions->lookaheads - LA) + r];

   sp->value = gotono;
   sp->value = gotono;

-  lookback[i] = sp;
+  lookback[(state->reductions->lookaheads - LA) + r] = sp;

 }
 
 
 }
 
 

-static void
-matrix_print (FILE *out, short **matrix, int n)
-{
-  int i, j;
-
-  for (i = 0; i < n; ++i)
-    {
-      fprintf (out, "%3d: ", i);
-      if (matrix[i])
-       for (j = 0; matrix[i][j] != -1; ++j)
-         fprintf (out, "%3d ", matrix[i][j]);
-      fputc ('\n', out);
-    }
-  fputc ('\n', out);
-}
-
-/*-------------------------------------------------------------------.
-| Return the transpose of R_ARG, of size N.  Destroy R_ARG, as it is |
-| replaced with the result.                                          |
-|                                                                    |
-| R_ARG[I] is NULL or a -1 terminated list of numbers.               |
-|                                                                    |
-| RESULT[NUM] is NULL or the -1 terminated list of the I such as NUM |
-| is in R_ARG[I].                                                    |
-`-------------------------------------------------------------------*/
-
-static short **
-transpose (short **R_arg, int n)
-{
-  /* The result. */
-  short **new_R = XCALLOC (short *, n);
-  /* END_R[I] -- next entry of NEW_R[I]. */
-  short **end_R = XCALLOC (short *, n);
-  /* NEDGES[I] -- total size of NEW_R[I]. */
-  short *nedges = XCALLOC (short, n);
-  int i, j;
-
-  if (trace_flag)
-    {
-      fputs ("transpose: input\n", stderr);
-      matrix_print (stderr, R_arg, n);
-    }
-
-  /* Count. */
-  for (i = 0; i < n; i++)
-    if (R_arg[i])
-      for (j = 0; R_arg[i][j] >= 0; ++j)
-       ++nedges[R_arg[i][j]];
-
-  /* Allocate. */
-  for (i = 0; i < n; i++)
-    if (nedges[i] > 0)
-      {
-       short *sp = XCALLOC (short, nedges[i] + 1);
-       sp[nedges[i]] = -1;
-       new_R[i] = sp;
-       end_R[i] = sp;
-      }
-
-  /* Store. */
-  for (i = 0; i < n; i++)
-    if (R_arg[i])
-      for (j = 0; R_arg[i][j] >= 0; ++j)
-       {
-         *end_R[R_arg[i][j]] = i;
-         ++end_R[R_arg[i][j]];
-       }
-
-  free (nedges);
-  free (end_R);
-
-  /* Free the input: it is replaced with the result. */
-  for (i = 0; i < n; i++)
-    XFREE (R_arg[i]);
-  free (R_arg);
-
-  if (trace_flag)
-    {
-      fputs ("transpose: output\n", stderr);
-      matrix_print (stderr, new_R, n);
-    }
-
-  return new_R;
-}
-

 
 static void
 build_relations (void)
 {
 
 static void
 build_relations (void)
 {

-  short *edge = XCALLOC (short, ngotos + 1);
-  short *states = XCALLOC (short, ritem_longest_rhs () + 1);
+  goto_number_t *edge = XCALLOC (goto_number_t, ngotos + 1);
+  state_number_t *states1 = XCALLOC (state_number_t, ritem_longest_rhs () + 1);

   int i;
 
   int i;
 

-  includes = XCALLOC (short *, ngotos);
+  includes = XCALLOC (goto_number_t *, ngotos);

 
   for (i = 0; i < ngotos; i++)
     {
       int nedges = 0;
 
   for (i = 0; i < ngotos; i++)
     {
       int nedges = 0;

-      int state1 = from_state[i];
-      int symbol1 = state_table[to_state[i]]->accessing_symbol;
-      short *rulep;
+      symbol_number_t symbol1 = states[to_state[i]]->accessing_symbol;
+      rule_t **rulep;

 
 

-      for (rulep = derives[symbol1]; *rulep > 0; rulep++)
+      for (rulep = derives[symbol1]; *rulep; rulep++)

        {
          int done;
          int length = 1;
        {
          int done;
          int length = 1;

-         int stateno = state1;
-         short *rp;
-         states[0] = state1;
+         item_number_t *rp;
+         state_t *state = states[from_state[i]];
+         states1[0] = state->number;

 
 

-         for (rp = ritem + rule_table[*rulep].rhs; *rp > 0; rp++)
+         for (rp = (*rulep)->rhs; *rp >= 0; rp++)

            {
            {

-             shifts *sp = state_table[stateno]->shifts;
-             int j;
-             for (j = 0; j < sp->nshifts; j++)
-               {
-                 stateno = sp->shifts[j];
-                 if (state_table[stateno]->accessing_symbol == *rp)
-                   break;
-               }
-
-             states[length++] = stateno;
+             state = transitions_to (state->transitions,
+                                     item_number_as_symbol_number (*rp));
+             states1[length++] = state->number;

            }
 
            }
 

-         if (!state_table[stateno]->consistent)
-           add_lookback_edge (stateno, *rulep, i);
+         if (!state->consistent)
+           add_lookback_edge (state, *rulep, i);

 
          length--;
          done = 0;
 
          length--;
          done = 0;


@@ -539,8 +264,9 @@ build_relations (void)
              /* JF added rp>=ritem &&   I hope to god its right! */
              if (rp >= ritem && ISVAR (*rp))
                {
              /* JF added rp>=ritem &&   I hope to god its right! */
              if (rp >= ritem && ISVAR (*rp))
                {

-                 stateno = states[--length];
-                 edge[nedges++] = map_goto (stateno, *rp);
+                 /* Downcasting from item_number_t to symbol_number_t. */
+                 edge[nedges++] = map_goto (states1[--length],
+                                            item_number_as_symbol_number (*rp));

                  if (nullable[*rp])
                    done = 0;
                }
                  if (nullable[*rp])
                    done = 0;
                }


@@ -550,7 +276,7 @@ build_relations (void)
       if (nedges)
        {
          int j;
       if (nedges)
        {
          int j;

-         includes[i] = XCALLOC (short, nedges + 1);
+         includes[i] = XCALLOC (goto_number_t, nedges + 1);

          for (j = 0; j < nedges; j++)
            includes[i][j] = edge[j];
          includes[i][nedges] = -1;
          for (j = 0; j < nedges; j++)
            includes[i][j] = edge[j];
          includes[i][nedges] = -1;


@@ -558,9 +284,9 @@ build_relations (void)
     }
 
   XFREE (edge);
     }
 
   XFREE (edge);

-  XFREE (states);
+  XFREE (states1);

 
 

-  includes = transpose (includes, ngotos);
+  relation_transpose (&includes, ngotos);

 }
 
 
 }
 
 


@@ -570,7 +296,7 @@ compute_FOLLOWS (void)
 {
   int i;
 
 {
   int i;
 

-  digraph (includes);
+  relation_digraph (includes, ngotos, &F);

 
   for (i = 0; i < ngotos; i++)
     XFREE (includes[i]);
 
   for (i = 0; i < ngotos; i++)
     XFREE (includes[i]);


@@ -582,37 +308,148 @@ compute_FOLLOWS (void)
 static void
 compute_lookaheads (void)
 {
 static void
 compute_lookaheads (void)
 {

-  int i;
-  shorts *sp;
+  size_t i;
+  goto_list_t *sp;

 
 

-  for (i = 0; i < state_table[nstates]->lookaheads; i++)
+  for (i = 0; i < nLA; i++)

     for (sp = lookback[i]; sp; sp = sp->next)
     for (sp = lookback[i]; sp; sp = sp->next)

-      {
-       int size = LA (i + 1) - LA (i);
-       int j;
-       for (j = 0; j < size; ++j)
-         LA (i)[j] |= F (sp->value)[j];
-      }
+      bitset_or (LA[i], LA[i], F[sp->value]);

 
   /* Free LOOKBACK. */
 
   /* Free LOOKBACK. */

-  for (i = 0; i < state_table[nstates]->lookaheads; i++)
-    LIST_FREE (shorts, lookback[i]);
+  for (i = 0; i < nLA; i++)
+    LIST_FREE (goto_list_t, lookback[i]);

 
   XFREE (lookback);
 
   XFREE (lookback);

-  XFREE (F);
+  bitsetv_free (F);

 }
 
 
 }
 
 

+/*---------------------------------------------------------------.
+| Count the number of lookaheads required for STATE (NLOOKAHEADS |
+| member).                                                       |
+`---------------------------------------------------------------*/
+
+static int
+state_lookaheads_count (state_t *state)
+{
+  int k;
+  int nlookaheads = 0;
+  reductions_t *rp = state->reductions;
+  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
+     reduction from a shift.  Otherwise, it is straightforward,
+     and the state is `consistent'.  */
+  if (rp->num > 1
+      || (rp->num == 1 && sp->num &&
+         !TRANSITION_IS_DISABLED (sp, 0) && TRANSITION_IS_SHIFT (sp, 0)))
+    nlookaheads += rp->num;
+  else
+    state->consistent = 1;
+
+  for (k = 0; k < sp->num; k++)
+    if (!TRANSITION_IS_DISABLED (sp, k) && TRANSITION_IS_ERROR (sp, k))
+      {
+       state->consistent = 0;
+       break;
+      }
+
+  return nlookaheads;
+}
+
+
+/*----------------------------------------------.
+| Compute LA, NLA, and the lookaheads members.  |
+`----------------------------------------------*/
+
+static void
+initialize_LA (void)
+{
+  state_number_t i;
+  bitsetv pLA;
+
+  /* Compute the total number of reductions requiring a lookahead.  */
+  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++)
+    {
+      int count = state_lookaheads_count (states[i]);
+      if (count)
+       {
+         states[i]->reductions->lookaheads = pLA;
+         pLA += count;
+       }
+    }
+}
+
+
+/*---------------------------------------.
+| Output the lookaheads for each state.  |
+`---------------------------------------*/
+
+static void
+lookaheads_print (FILE *out)
+{
+  state_number_t i;
+  int j, k;
+  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, nlookaheads);
+
+      if (reds->lookaheads)
+       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,
+                    reds->rules[j]->number);
+         };
+    }
+  fprintf (out, "Lookaheads: END\n");
+}
+

 void
 lalr (void)
 {
 void
 lalr (void)
 {

-  tokensetsize = WORDSIZE (ntokens);
-
-  set_state_table ();

   initialize_LA ();
   set_goto_map ();
   initialize_F ();
   build_relations ();
   compute_FOLLOWS ();
   compute_lookaheads ();
   initialize_LA ();
   set_goto_map ();
   initialize_F ();
   build_relations ();
   compute_FOLLOWS ();
   compute_lookaheads ();

+
+  if (trace_flag & trace_sets)
+    lookaheads_print (stderr);
+}
+
+
+void
+lalr_free (void)
+{
+  state_number_t s;
+  for (s = 0; s < nstates; ++s)
+    states[s]->reductions->lookaheads = NULL;
+  bitsetv_free (LA);

 }
 }