* src/lalr.c (F): Now a bitset*.

[bison.git] / src / lalr.c

diff --git a/src/lalr.c b/src/lalr.c
index 4b11caaa7d124ecaeccee297da91031368ddb26f..87e91cd5f553e9857ab345cba7c43bb07eae3123 100644 (file)
--- a/src/lalr.c
+++ b/src/lalr.c
@@ -1,5 +1,5 @@
 /* Compute look-ahead criteria for bison,
 /* Compute look-ahead criteria for bison,

-   Copyright 1984, 1986, 1989, 2000 Free Software Foundation, Inc.
+   Copyright 1984, 1986, 1989, 2000, 2001  Free Software Foundation, Inc.

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


@@ -24,99 +24,84 @@
    tokens they accept.  */
 
 #include "system.h"
    tokens they accept.  */
 
 #include "system.h"

+#include "bitset.h"
+#include "reader.h"

 #include "types.h"
 #include "LR0.h"
 #include "types.h"
 #include "LR0.h"

+#include "symtab.h"

 #include "gram.h"
 #include "complain.h"
 #include "lalr.h"
 #include "nullable.h"
 #include "derives.h"
 #include "gram.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;
+/* All the decorated states, indexed by the state number.  */
+state_t **states = NULL;

 
 int tokensetsize;
 
 int tokensetsize;

-short *lookaheads;
-short *LAruleno;
-unsigned *LA;
+short *LAruleno = NULL;
+bitset *LA = NULL;
+size_t nLA;

 
 

-char *consistent;
-shifts **shift_table;
-reductions **reduction_table;
-short *goto_map;
-short *from_state;
-short *to_state;
+static int ngotos;
+short *goto_map = NULL;
+short *from_state = NULL;
+short *to_state = NULL;

 
 

-extern void berror PARAMS ((const char *));
+/* And for the famous F variable, which name is so descriptive that a
+   comment is hardly needed.  <grin>.  */
+static bitset *F = NULL;

 
 

-static int infinity;
-static int maxrhs;
-static int ngotos;
-static unsigned *F;

 static short **includes;
 static shorts **lookback;
 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 short **R;
 static short *INDEX;
 static short *VERTICES;
 static int top;

-
+static int infinity;

 
 static void
 traverse (int i)
 {
 
 static void
 traverse (int i)
 {

-  unsigned *fp1;
-  unsigned *fp2;
-  unsigned *fp3;

   int j;
   int j;

-  short *rp;
-

   int height;
   int height;

-  unsigned *base;

 
   VERTICES[++top] = i;
   INDEX[i] = height = top;
 
 
   VERTICES[++top] = i;
   INDEX[i] = height = top;
 

-  base = F + i * tokensetsize;
-  fp3 = base + tokensetsize;
-
-  rp = R[i];
-  if (rp)
-    {
-      while ((j = *rp++) >= 0)
-       {
-         if (INDEX[j] == 0)
-           traverse (j);
+  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[j])
-           INDEX[i] = INDEX[j];
+       if (INDEX[i] > INDEX[R[i][j]])
+         INDEX[i] = INDEX[R[i][j]];

 
 

-         fp1 = base;
-         fp2 = F + j * tokensetsize;
-
-         while (fp1 < fp3)
-           *fp1++ |= *fp2++;
-       }
-    }
+       bitset_or (F[i], F[i], F[R[i][j]]);
+      }

 
   if (INDEX[i] == height)
 
   if (INDEX[i] == height)

-    {
-      for (;;)
-       {
-         j = VERTICES[top--];
-         INDEX[j] = infinity;
+    for (;;)
+      {
+       j = VERTICES[top--];
+       INDEX[j] = infinity;

 
 

-         if (i == j)
-           break;
+       if (i == j)
+         break;

 
 

-         fp1 = base;
-         fp2 = F + j * tokensetsize;
-
-         while (fp1 < fp3)
-           *fp2++ = *fp1++;
-       }
-    }
+       bitset_copy (F[j], F[i]);
+      }

 }
 
 
 }
 
 


@@ -136,210 +121,92 @@ digraph (short **relation)
     INDEX[i] = 0;
 
   for (i = 0; i < ngotos; i++)
     INDEX[i] = 0;
 
   for (i = 0; i < ngotos; i++)

-    {
-      if (INDEX[i] == 0 && R[i])
-       traverse (i);
-    }
+    if (INDEX[i] == 0 && R[i])
+      traverse (i);

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

-static void
-set_state_table (void)
-{
-  core *sp;
-
-  state_table = XCALLOC (state_t, nstates);
-
-  for (sp = first_state; sp; sp = sp->next)
-    {
-      state_table[sp->number].state = sp;
-      state_table[sp->number].accessing_symbol = sp->accessing_symbol;
-    }
-}
-
-
-static void
-set_shift_table (void)
-{
-  shifts *sp;
-
-  shift_table = XCALLOC (shifts *, nstates);
-
-  for (sp = first_shift; sp; sp = sp->next)
-    shift_table[sp->number] = sp;
-}
-
-
-static void
-set_reduction_table (void)
-{
-  reductions *rp;
-
-  reduction_table = XCALLOC (reductions *, nstates);
-
-  for (rp = first_reduction; rp; rp = rp->next)
-    reduction_table[rp->number] = rp;
-}
-
-
-static void
-set_maxrhs (void)
-{
-  short *itemp;
-  int length;
-  int max;
-
-  length = 0;
-  max = 0;
-  for (itemp = ritem; *itemp; itemp++)
-    {
-      if (*itemp > 0)
-       {
-         length++;
-       }
-      else
-       {
-         if (length > max)
-           max = length;
-         length = 0;
-       }
-    }
-
-  maxrhs = max;
-}
-

 
 static void
 initialize_LA (void)
 {
 
 static void
 initialize_LA (void)
 {

-  int i;
+  size_t i;

   int j;
   int j;

-  int count;
-  reductions *rp;
-  shifts *sp;

   short *np;
 
   short *np;
 

-  consistent = XCALLOC (char, nstates);
-  lookaheads = XCALLOC (short, nstates + 1);
-
-  count = 0;
-  for (i = 0; i < nstates; i++)
-    {
-      int k;
-
-      lookaheads[i] = count;
-
-      rp = reduction_table[i];
-      sp = shift_table[i];
-      if (rp
-         && (rp->nreds > 1
-             || (sp && !ISVAR (state_table[sp->shifts[0]].accessing_symbol))))
-       count += rp->nreds;
-      else
-       consistent[i] = 1;
-
-      if (sp)
-       for (k = 0; k < sp->nshifts; k++)
-         if (state_table[sp->shifts[k]].accessing_symbol
-             == error_token_number)
-           {
-             consistent[i] = 0;
-             break;
-           }
-    }
-
-  lookaheads[nstates] = count;
+  /* Avoid having to special case 0.  */
+  if (!nLA)
+    nLA = 1;

 
 

-  if (count == 0)
+  LA = XCALLOC (bitset, nLA);
+  for (i = 0; i < nLA; ++i)

     {
     {

-      LA = XCALLOC (unsigned, 1 * tokensetsize);
-      LAruleno = XCALLOC (short, 1);
-      lookback = XCALLOC (shorts *, 1);
-    }
-  else
-    {
-      LA = XCALLOC (unsigned, count * tokensetsize);
-      LAruleno = XCALLOC (short, count);
-      lookback = XCALLOC (shorts *, count);
+      LA[i] = bitset_create (ntokens, BITSET_FIXED);
+      bitset_zero (LA[i]);

     }
     }

+  LAruleno = XCALLOC (short, nLA);
+  lookback = XCALLOC (shorts *, nLA);

 
   np = LAruleno;
   for (i = 0; i < nstates; i++)
 
   np = LAruleno;
   for (i = 0; i < nstates; i++)

-    {
-      if (!consistent[i])
-       {
-         if ((rp = reduction_table[i]))
-           for (j = 0; j < rp->nreds; j++)
-             *np++ = rp->rules[j];
-       }
-    }
+    if (!states[i]->consistent)
+      for (j = 0; j < states[i]->reductions->nreds; j++)
+       *np++ = states[i]->reductions->rules[j];

 }
 
 
 static void
 set_goto_map (void)
 {
 }
 
 
 static void
 set_goto_map (void)
 {

-  shifts *sp;
+  size_t state;

   int i;
   int i;

-  int symbol;
-  int k;

   short *temp_map;
   short *temp_map;

-  int state2;
-  int state1;

 
   goto_map = XCALLOC (short, nvars + 1) - ntokens;
   temp_map = XCALLOC (short, nvars + 1) - ntokens;
 
   ngotos = 0;
 
   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 (state = 0; state < nstates; ++state)

     {
     {

-      for (i = sp->nshifts - 1; i >= 0; i--)
+      shifts *sp = states[state]->shifts;
+      for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)

        {
        {

-         symbol = state_table[sp->shifts[i]].accessing_symbol;
-
-         if (ISTOKEN (symbol))
-           break;
-

          if (ngotos == MAXSHORT)
            fatal (_("too many gotos (max %d)"), MAXSHORT);
 
          ngotos++;
          if (ngotos == MAXSHORT)
            fatal (_("too many gotos (max %d)"), MAXSHORT);
 
          ngotos++;

-         goto_map[symbol]++;
+         goto_map[SHIFT_SYMBOL (sp, i)]++;

        }
     }
 
        }
     }
 

-  k = 0;
-  for (i = ntokens; i < nsyms; i++)
-    {
-      temp_map[i] = k;
-      k += goto_map[i];
-    }
+  {
+    int 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 (short, ngotos);
   to_state = XCALLOC (short, 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; i--)
+      shifts *sp = states[state]->shifts;
+      for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)

        {
        {

-         state2 = sp->shifts[i];
-         symbol = state_table[state2].accessing_symbol;
-
-         if (ISTOKEN (symbol))
-           break;
-
-         k = temp_map[symbol]++;
-         from_state[k] = state1;
-         to_state[k] = state2;
+         int k = temp_map[SHIFT_SYMBOL (sp, i)]++;
+         from_state[k] = state;
+         to_state[k] = sp->shifts[i];

        }
     }
 
        }
     }
 


@@ -384,73 +251,48 @@ map_goto (int state, int symbol)
 static void
 initialize_F (void)
 {
 static void
 initialize_F (void)
 {

-  int i;
-  int j;
-  int k;
-  shifts *sp;
-  short *edge;
-  unsigned *rowp;
-  short *rp;
-  short **reads;
-  int nedges;
-  int stateno;
-  int symbol;
-  int nwords;
-
-  nwords = ngotos * tokensetsize;
-  F = XCALLOC (unsigned, nwords);
-
-  reads = XCALLOC (short *, ngotos);
-  edge = XCALLOC (short, ngotos + 1);
-  nedges = 0;
-
-  rowp = F;
-  for (i = 0; i < ngotos; i++)
-    {
-      stateno = to_state[i];
-      sp = shift_table[stateno];
-
-      if (sp)
-       {
-         k = sp->nshifts;
+  short **reads = XCALLOC (short *, ngotos);
+  short *edge = XCALLOC (short, ngotos + 1);
+  int nedges = 0;

 
 

-         for (j = 0; j < k; j++)
-           {
-             symbol = state_table[sp->shifts[j]].accessing_symbol;
-             if (ISVAR (symbol))
-               break;
-             SETBIT (rowp, symbol);
-           }
+  int i;

 
 

-         for (; j < k; j++)
-           {
-             symbol = state_table[sp->shifts[j]].accessing_symbol;
-             if (nullable[symbol])
-               edge[nedges++] = map_goto (stateno, symbol);
-           }
+  F = XCALLOC (bitset, ngotos);
+  for (i = 0; i < ngotos; ++i)
+    {
+      F[i] = bitset_create (ntokens, BITSET_FIXED);
+      bitset_zero (F[i]);
+    }

 
 

-         if (nedges)
-           {
-             reads[i] = rp = XCALLOC (short, nedges + 1);
+  for (i = 0; i < ngotos; i++)
+    {
+      int stateno = to_state[i];
+      shifts *sp = states[stateno]->shifts;

 
 

-             for (j = 0; j < nedges; j++)
-               rp[j] = edge[j];
+      int j;
+      for (j = 0; j < sp->nshifts && SHIFT_IS_SHIFT (sp, j); j++)
+       bitset_set (F[i], SHIFT_SYMBOL (sp, j));

 
 

-             rp[nedges] = -1;
-             nedges = 0;
-           }
+      for (; j < sp->nshifts; j++)
+       {
+         int symbol = SHIFT_SYMBOL (sp, j);
+         if (nullable[symbol])
+           edge[nedges++] = map_goto (stateno, symbol);

        }
 
        }
 

-      rowp += tokensetsize;
+      if (nedges)
+       {
+         reads[i] = XCALLOC (short, nedges + 1);
+         shortcpy (reads[i], edge, nedges);
+         reads[i][nedges] = -1;
+         nedges = 0;
+       }

     }
 
   digraph (reads);
 
   for (i = 0; i < ngotos; i++)
     }
 
   digraph (reads);
 
   for (i = 0; i < ngotos; i++)

-    {
-      if (reads[i])
-       XFREE (reads[i]);
-    }
+    XFREE (reads[i]);

 
   XFREE (reads);
   XFREE (edge);
 
   XFREE (reads);
   XFREE (edge);


@@ -458,84 +300,106 @@ initialize_F (void)
 
 
 static void
 
 
 static void

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

 {
   int i;
 {
   int i;

-  int k;
-  int found;

   shorts *sp;
 
   shorts *sp;
 

-  i = lookaheads[stateno];
-  k = lookaheads[stateno + 1];
-  found = 0;
-  while (!found && i < k)
-    {
-      if (LAruleno[i] == ruleno)
-       found = 1;
-      else
-       i++;
-    }
+  for (i = 0; i < state->nlookaheads; ++i)
+    if (LAruleno[state->lookaheadsp + i] == ruleno)
+      break;

 
 

-  assert (found);
+  assert (LAruleno[state->lookaheadsp + i] == ruleno);

 
   sp = XCALLOC (shorts, 1);
 
   sp = XCALLOC (shorts, 1);

-  sp->next = lookback[i];
+  sp->next = lookback[state->lookaheadsp + i];

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

-  lookback[i] = sp;
+  lookback[state->lookaheadsp + i] = sp;

 }
 
 
 }
 
 

-static short **
-transpose (short **R_arg, int n)
+static void
+matrix_print (FILE *out, short **matrix, int n)

 {
 {

-  short **new_R;
-  short **temp_R;
-  short *nedges;
-  short *sp;
-  int i;
-  int k;
+  int i, j;

 
 

-  nedges = XCALLOC (short, n);
+  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);
+}

 
 

-  for (i = 0; i < n; i++)
+/*-------------------------------------------------------------------.
+| 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)

     {
     {

-      sp = R_arg[i];
-      if (sp)
-       {
-         while (*sp >= 0)
-           nedges[*sp++]++;
-       }
+      fputs ("transpose: input\n", stderr);
+      matrix_print (stderr, R_arg, n);

     }
 
     }
 

-  new_R = XCALLOC (short *, n);
-  temp_R = XCALLOC (short *, 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++)
   for (i = 0; i < n; i++)

-    {
-      k = nedges[i];
-      if (k > 0)
+    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)

        {
        {

-         sp = XCALLOC (short, k + 1);
-         new_R[i] = sp;
-         temp_R[i] = sp;
-         sp[k] = -1;
+         *end_R[R_arg[i][j]] = i;
+         ++end_R[R_arg[i][j]];

        }
        }

-    }

 
 

-  XFREE (nedges);
+  free (nedges);
+  free (end_R);

 
 

+  /* Free the input: it is replaced with the result. */

   for (i = 0; i < n; i++)
   for (i = 0; i < n; i++)

+    XFREE (R_arg[i]);
+  free (R_arg);
+
+  if (trace_flag)

     {
     {

-      sp = R_arg[i];
-      if (sp)
-       {
-         while (*sp >= 0)
-           *temp_R[*sp++]++ = i;
-       }
+      fputs ("transpose: output\n", stderr);
+      matrix_print (stderr, new_R, n);

     }
 
     }
 

-  XFREE (temp_R);
-

   return new_R;
 }
 
   return new_R;
 }
 


@@ -543,58 +407,42 @@ transpose (short **R_arg, int n)
 static void
 build_relations (void)
 {
 static void
 build_relations (void)
 {

+  short *edge = XCALLOC (short, ngotos + 1);
+  short *states1 = XCALLOC (short, ritem_longest_rhs () + 1);

   int i;
   int i;

-  int j;
-  int k;
-  short *rulep;
-  short *rp;
-  shifts *sp;
-  int length;
-  int nedges;
-  int done;
-  int state1;
-  int stateno;
-  int symbol1;
-  int symbol2;
-  short *shortp;
-  short *edge;
-  short *states;
-  short **new_includes;

 
   includes = XCALLOC (short *, ngotos);
 
   includes = XCALLOC (short *, ngotos);

-  edge = XCALLOC (short, ngotos + 1);
-  states = XCALLOC (short, maxrhs + 1);

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

-      nedges = 0;
-      state1 = from_state[i];
-      symbol1 = state_table[to_state[i]].accessing_symbol;
+      int nedges = 0;
+      int symbol1 = states[to_state[i]]->accessing_symbol;
+      short *rulep;

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

-         length = 1;
-         states[0] = state1;
-         stateno = state1;
+         int done;
+         int length = 1;
+         short *rp;
+         state_t *state = states[from_state[i]];
+         states1[0] = state->number;

 
 

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

            {
            {

-             symbol2 = *rp;
-             sp = shift_table[stateno];
-             k = sp->nshifts;
-
-             for (j = 0; j < k; j++)
+             shifts *sp = state->shifts;
+             int j;
+             for (j = 0; j < sp->nshifts; j++)

                {
                {

-                 stateno = sp->shifts[j];
-                 if (state_table[stateno].accessing_symbol == symbol2)
+                 state = states[sp->shifts[j]];
+                 if (state->accessing_symbol == *rp)

                    break;
                }
 
                    break;
                }
 

-             states[length++] = stateno;
+             states1[length++] = state->number;

            }
 
            }
 

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

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


@@ -605,8 +453,7 @@ 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);
+                 edge[nedges++] = map_goto (states1[--length], *rp);

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


@@ -615,25 +462,18 @@ build_relations (void)
 
       if (nedges)
        {
 
       if (nedges)
        {

-         includes[i] = shortp = XCALLOC (short, nedges + 1);
+         int j;
+         includes[i] = XCALLOC (short, nedges + 1);

          for (j = 0; j < nedges; j++)
          for (j = 0; j < nedges; j++)

-           shortp[j] = edge[j];
-         shortp[nedges] = -1;
+           includes[i][j] = edge[j];
+         includes[i][nedges] = -1;

        }
     }
 
        }
     }
 

-  new_includes = transpose (includes, ngotos);
-
-  for (i = 0; i < ngotos; i++)
-    if (includes[i])
-      XFREE (includes[i]);
-
-  XFREE (includes);
-
-  includes = new_includes;
-

   XFREE (edge);
   XFREE (edge);

-  XFREE (states);
+  XFREE (states1);
+
+  includes = transpose (includes, ngotos);

 }
 
 
 }
 
 


@@ -646,10 +486,7 @@ compute_FOLLOWS (void)
   digraph (includes);
 
   for (i = 0; i < ngotos; i++)
   digraph (includes);
 
   for (i = 0; i < ngotos; i++)

-    {
-      if (includes[i])
-       XFREE (includes[i]);
-    }
+    XFREE (includes[i]);

 
   XFREE (includes);
 }
 
   XFREE (includes);
 }


@@ -658,59 +495,102 @@ compute_FOLLOWS (void)
 static void
 compute_lookaheads (void)
 {
 static void
 compute_lookaheads (void)
 {

-  int i;
-  int n;
-  unsigned *fp1;
-  unsigned *fp2;
-  unsigned *fp3;
+  size_t i;

   shorts *sp;
   shorts *sp;

-  unsigned *rowp;
-  shorts *sptmp;               /* JF */

 
 

-  rowp = LA;
-  n = lookaheads[nstates];
-  for (i = 0; i < n; i++)
+  for (i = 0; i < nLA; i++)
+    for (sp = lookback[i]; sp; sp = sp->next)
+      bitset_or (LA[i], LA[i], F[sp->value]);
+
+  /* Free LOOKBACK. */
+  for (i = 0; i < nLA; i++)
+    LIST_FREE (shorts, lookback[i]);
+
+  XFREE (lookback);
+  for (i = 0; i < (unsigned) ngotos; ++i)
+    bitset_free (F[i]);
+  XFREE (F);
+}
+
+
+/*--------------------------------------.
+| Initializing the lookaheads members.  |
+`--------------------------------------*/
+
+static void
+initialize_lookaheads (void)
+{
+  size_t i;
+  nLA = 0;
+  for (i = 0; i < nstates; i++)

     {
     {

-      fp3 = rowp + tokensetsize;
-      for (sp = lookback[i]; sp; sp = sp->next)
-       {
-         fp1 = rowp;
-         fp2 = F + tokensetsize * sp->value;
-         while (fp1 < fp3)
-           *fp1++ |= *fp2++;
-       }
+      int k;
+      int nlookaheads = 0;
+      reductions *rp = states[i]->reductions;
+      shifts *sp = states[i]->shifts;
+
+      /* 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->nreds > 1
+         || (rp->nreds == 1 && sp->nshifts && SHIFT_IS_SHIFT (sp, 0)))
+       nlookaheads += rp->nreds;
+      else
+       states[i]->consistent = 1;
+
+      for (k = 0; k < sp->nshifts; k++)
+       if (SHIFT_IS_ERROR (sp, k))
+         {
+           states[i]->consistent = 0;
+           break;
+         }

 
 

-      rowp = fp3;
+      states[i]->nlookaheads = nlookaheads;
+      states[i]->lookaheadsp = nLA;
+      nLA += nlookaheads;

     }
     }

+}

 
 

-  for (i = 0; i < n; i++)
+
+/*---------------------------------------.
+| Output the lookaheads for each state.  |
+`---------------------------------------*/
+
+static void
+lookaheads_print (FILE *out)
+{
+  size_t i;
+  int j, k;
+  fprintf (out, "Lookaheads: BEGIN\n");
+  for (i = 0; i < nstates; ++i)

     {
     {

-      /* JF removed ref to freed storage */
-      for (sp = lookback[i]; sp; sp = sptmp)
-       {
-         sptmp = sp->next;
-         XFREE (sp);
-       }
+      fprintf (out, "State %d: %d lookaheads\n",
+              i, states[i]->nlookaheads);
+
+      for (j = 0; j < states[i]->nlookaheads; ++j)
+       for (k = 0; k < ntokens; ++k)
+         if (bitset_test (LA[states[i]->lookaheadsp + j], j))
+           fprintf (out, "   on %d (%s) -> rule %d\n",
+                    k, symbols[k]->tag,
+                    -LAruleno[states[i]->lookaheadsp + j] - 1);

     }
     }

-
-  XFREE (lookback);
-  XFREE (F);
+  fprintf (out, "Lookaheads: END\n");

 }
 
 }
 

-

 void
 lalr (void)
 {
   tokensetsize = WORDSIZE (ntokens);
 
 void
 lalr (void)
 {
   tokensetsize = WORDSIZE (ntokens);
 

-  set_state_table ();
-  set_shift_table ();
-  set_reduction_table ();
-  set_maxrhs ();
+  initialize_lookaheads ();

   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)
+    lookaheads_print (stderr);

 }
 }