Point to an official beta.

[bison.git] / src / lalr.c

diff --git a/src/lalr.c b/src/lalr.c
index f7d92ec72674fbe3013ecb6dff96643512860711..643f8fd91d20ab78bf6f460dde57cd424e8f67d1 100644 (file)
--- a/src/lalr.c
+++ b/src/lalr.c
@@ -1,348 +1,228 @@
 /* Compute look-ahead criteria for bison,
 /* Compute look-ahead criteria for bison,

-   Copyright (C) 1984, 1986, 1989 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.

 
 

-Bison is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2, or (at your option)
-any later version.
+   Bison is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.

 
 

-Bison is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU General Public License for more details.
+   Bison is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.

 
 

-You should have received a copy of the GNU General Public License
-along with Bison; see the file COPYING.  If not, write to
-the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+   You should have received a copy of the GNU General Public License
+   along with Bison; see the file COPYING.  If not, write to
+   the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */

 
 
 
 

-/* Compute how to make the finite state machine deterministic;
- find which rules need lookahead in each state, and which lookahead tokens they accept.
+/* Compute how to make the finite state machine deterministic; find
+   which rules need lookahead in each state, and which lookahead
+   tokens they accept.  */

 
 

-lalr(), the entry point, builds these data structures:
-
-goto_map, from_state and to_state 
- record each shift transition which accepts a variable (a nonterminal).
-ngotos is the number of such transitions.
-from_state[t] is the state number which a transition leads from
-and to_state[t] is the state number it leads to.
-All the transitions that accept a particular variable are grouped together and
-goto_map[i - ntokens] is the index in from_state and to_state of the first of them.
-
-consistent[s] is nonzero if no lookahead is needed to decide what to do in state s.
-
-LAruleno is a vector which records the rules that need lookahead in various states.
-The elements of LAruleno that apply to state s are those from
- lookaheads[s] through lookaheads[s+1]-1.
-Each element of LAruleno is a rule number.
-
-If lr is the length of LAruleno, then a number from 0 to lr-1 
-can specify both a rule and a state where the rule might be applied.
-
-LA is a lr by ntokens matrix of bits.
-LA[l, i] is 1 if the rule LAruleno[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.
-*/
-
-#include <stdio.h>

 #include "system.h"
 #include "system.h"

-#include "machine.h"
-#include "types.h"
-#include "state.h"
-#include "new.h"
+#include "bitset.h"
+#include "bitsetv.h"
+#include "quotearg.h"
+#include "symtab.h"

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

+#include "reader.h"
+#include "types.h"
+#include "LR0.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.  */
+state_t **states = NULL;

 
 

-extern short **derives;
-extern char *nullable;
-
-
-int tokensetsize;
-short *lookaheads;
-short *LAruleno;
-unsigned *LA;
-short *accessing_symbol;
-char *consistent;
-core **state_table;
-shifts **shift_table;
-reductions **reduction_table;
-short *goto_map;
-short *from_state;
-short *to_state;
-
-short **transpose();
-void set_state_table();
-void set_accessing_symbol();
-void set_shift_table();
-void set_reduction_table();
-void set_maxrhs();
-void initialize_LA();
-void set_goto_map();
-void initialize_F();
-void build_relations();
-void add_lookback_edge();
-void compute_FOLLOWS();
-void compute_lookaheads();
-void digraph();
-void traverse();
-
-extern void toomany();
-extern void berror();
+rule_t **LArule = NULL;
+bitsetv LA = NULL;
+size_t nLA;

 
 

-static int infinity;
-static int maxrhs;

 static int ngotos;
 static int ngotos;

-static unsigned *F;
+short *goto_map = NULL;
+short *from_state = NULL;
+short *to_state = NULL;
+
+/* And for the famous F variable, which name is so descriptive that a
+   comment is hardly needed.  <grin>.  */
+static bitsetv F = NULL;
+

 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;

 
 

-
-void
-lalr()
-{
-  tokensetsize = WORDSIZE(ntokens);
-
-  set_state_table();
-  set_accessing_symbol();
-  set_shift_table();
-  set_reduction_table();
-  set_maxrhs();
-  initialize_LA();
-  set_goto_map();
-  initialize_F();
-  build_relations();
-  compute_FOLLOWS();
-  compute_lookaheads();
-}
-
-
-void
-set_state_table()
+static void
+traverse (int i)

 {
 {

-  register core *sp;
-
-  state_table = NEW2(nstates, core *);
-
-  for (sp = first_state; sp; sp = sp->next)
-    state_table[sp->number] = sp;
-}
-
+  int j;
+  int height;

 
 

-void
-set_accessing_symbol()
-{
-  register core *sp;
+  VERTICES[++top] = i;
+  INDEX[i] = height = top;

 
 

-  accessing_symbol = NEW2(nstates, short);
+  if (R[i])
+    for (j = 0; R[i][j] >= 0; ++j)
+      {
+       if (INDEX[R[i][j]] == 0)
+         traverse (R[i][j]);

 
 

-  for (sp = first_state; sp; sp = sp->next)
-    accessing_symbol[sp->number] = sp->accessing_symbol;
-}
+       if (INDEX[i] > INDEX[R[i][j]])
+         INDEX[i] = INDEX[R[i][j]];

 
 

+       bitset_or (F[i], F[i], F[R[i][j]]);
+      }

 
 

-void
-set_shift_table()
-{
-  register shifts *sp;
+  if (INDEX[i] == height)
+    for (;;)
+      {
+       j = VERTICES[top--];
+       INDEX[j] = infinity;

 
 

-  shift_table = NEW2(nstates, shifts *);
+       if (i == j)
+         break;

 
 

-  for (sp = first_shift; sp; sp = sp->next)
-    shift_table[sp->number] = sp;
+       bitset_copy (F[j], F[i]);
+      }

 }
 
 
 }
 
 

-void
-set_reduction_table()
+static void
+digraph (short **relation)

 {
 {

-  register reductions *rp;
+  int i;

 
 

-  reduction_table = NEW2(nstates, reductions *);
-
-  for (rp = first_reduction; rp; rp = rp->next)
-    reduction_table[rp->number] = rp;
-}
+  infinity = ngotos + 2;
+  INDEX = XCALLOC (short, ngotos + 1);
+  VERTICES = XCALLOC (short, ngotos + 1);
+  top = 0;

 
 

+  R = relation;

 
 

-void
-set_maxrhs()
-{
-  register short *itemp;
-  register int length;
-  register int max;
+  for (i = 0; i < ngotos; i++)
+    INDEX[i] = 0;

 
 

-  length = 0;
-  max = 0;
-  for (itemp = ritem; *itemp; itemp++)
-    {
-      if (*itemp > 0)
-       {
-         length++;
-       }
-      else
-       {
-         if (length > max) max = length;
-         length = 0;
-       }
-    }
+  for (i = 0; i < ngotos; i++)
+    if (INDEX[i] == 0 && R[i])
+      traverse (i);

 
 

-  maxrhs = max;
+  XFREE (INDEX);
+  XFREE (VERTICES);

 }
 
 
 }
 
 

-void
-initialize_LA()
+static void
+initialize_LA (void)

 {
 {

-  register int i;
-  register int j;
-  register int count;
-  register reductions *rp;
-  register shifts *sp;
-  register short *np;
-
-  consistent = NEW2(nstates, char);
-  lookaheads = NEW2(nstates + 1, short);
+  size_t i;
+  int j;
+  rule_t **np;

 
 

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

 
 

-      if (sp)
-       for (k = 0; k < sp->nshifts; k++)
-         {
-           if (accessing_symbol[sp->shifts[k]] == error_token_number)
-             {
-               consistent[i] = 0;
-               break;
-             }
-         }
-    }
+  LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
+  LArule = XCALLOC (rule_t *, nLA);
+  lookback = XCALLOC (shorts *, nLA);

 
 

-  lookaheads[nstates] = count;
-
-  if (count == 0)
-    {
-      LA = NEW2(1 * tokensetsize, unsigned);
-      LAruleno = NEW2(1, short);
-      lookback = NEW2(1, shorts *);
-    }
-  else
-    {
-      LA = NEW2(count * tokensetsize, unsigned);
-      LAruleno = NEW2(count, short);
-      lookback = NEW2(count, shorts *);
-    }
-
-  np = LAruleno;
+  np = LArule;

   for (i = 0; i < nstates; i++)
   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++ = &rules[states[i]->reductions->rules[j]];

 }
 
 
 }
 
 

-void
-set_goto_map()
+static void
+set_goto_map (void)

 {
 {

-  register shifts *sp;
-  register int i;
-  register int symbol;
-  register int k;
-  register short *temp_map;
-  register int state2;
-  register int state1;
+  size_t state;
+  int i;
+  short *temp_map;

 
 

-  goto_map = NEW2(nvars + 1, short) - ntokens;
-  temp_map = NEW2(nvars + 1, short) - ntokens;
+  goto_map = XCALLOC (short, nvars + 1) - ntokens;
+  temp_map = XCALLOC (short, nvars + 1) - ntokens;

 
   ngotos = 0;
 
   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 = accessing_symbol[sp->shifts[i]];
-
-         if (ISTOKEN(symbol)) break;
-
-         if (ngotos == MAXSHORT)
-           toomany(_("gotos"));
+         if (ngotos == SHRT_MAX)
+           fatal (_("too many gotos (max %d)"), SHRT_MAX);

 
          ngotos++;
 
          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 = NEW2(ngotos, short);
-  to_state = NEW2(ngotos, short);
+  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 = accessing_symbol[state2];
-
-         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];

        }
     }
 
        }
     }
 

-  FREE(temp_map + ntokens);
+  XFREE (temp_map + ntokens);

 }
 
 
 
 }
 
 
 

-/*  Map_goto maps a state/symbol pair into its numeric representation. */
+/*----------------------------------------------------------.
+| Map a state/symbol pair into its numeric representation.  |
+`----------------------------------------------------------*/

 
 

-int
-map_goto(state, symbol)
-int state;
-int symbol;
+static int
+map_goto (int state, token_number_t symbol)

 {
 {

-  register int high;
-  register int low;
-  register int middle;
-  register int s;
+  int high;
+  int low;
+  int middle;
+  int s;

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


@@ -352,419 +232,356 @@ int symbol;
       middle = (low + high) / 2;
       s = from_state[middle];
       if (s == state)
       middle = (low + high) / 2;
       s = from_state[middle];
       if (s == state)

-       return (middle);
+       return middle;

       else if (s < state)
        low = middle + 1;
       else
        high = middle - 1;
     }
 
       else if (s < state)
        low = middle + 1;
       else
        high = middle - 1;
     }
 

-  berror("map_goto");
-/* NOTREACHED */
+  assert (0);
+  /* NOTREACHED */

   return 0;
 }
 
 
   return 0;
 }
 
 

-void
-initialize_F()
+static void
+initialize_F (void)

 {
 {

-  register int i;
-  register int j;
-  register int k;
-  register shifts *sp;
-  register short *edge;
-  register unsigned *rowp;
-  register short *rp;
-  register short **reads;
-  register int nedges;
-  register int stateno;
-  register int symbol;
-  register int nwords;
-
-  nwords = ngotos * tokensetsize;
-  F = NEW2(nwords, unsigned);
-
-  reads = NEW2(ngotos, short *);
-  edge = NEW2(ngotos + 1, short);
-  nedges = 0;
-
-  rowp = F;
-  for (i = 0; i < ngotos; i++)
-    {
-      stateno = to_state[i];
-      sp = shift_table[stateno];
-
-      if (sp)
-       {
-         k = sp->nshifts;
-
-         for (j = 0; j < k; j++)
-           {
-             symbol = accessing_symbol[sp->shifts[j]];
-             if (ISVAR(symbol))
-               break;
-             SETBIT(rowp, symbol);
-           }
-
-         for (; j < k; j++)
-           {
-             symbol = accessing_symbol[sp->shifts[j]];
-             if (nullable[symbol])
-               edge[nedges++] = map_goto(stateno, symbol);
-           }
-       
-         if (nedges)
-           {
-             reads[i] = rp = NEW2(nedges + 1, short);
-
-             for (j = 0; j < nedges; j++)
-               rp[j] = edge[j];
-
-             rp[nedges] = -1;
-             nedges = 0;
-           }
-       }
+  short **reads = XCALLOC (short *, ngotos);
+  short *edge = XCALLOC (short, ngotos + 1);
+  int nedges = 0;

 
 

-      rowp += tokensetsize;
-    }
+  int i;

 
 

-  digraph(reads);
+  F = bitsetv_create (ngotos, ntokens, BITSET_FIXED);

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

-      if (reads[i])
-       FREE(reads[i]);
-    }
-
-  FREE(reads);
-  FREE(edge);
-}
-
-
-void
-build_relations()
-{
-  register int i;
-  register int j;
-  register int k;
-  register short *rulep;
-  register short *rp;
-  register shifts *sp;
-  register int length;
-  register int nedges;
-  register int done;
-  register int state1;
-  register int stateno;
-  register int symbol1;
-  register int symbol2;
-  register short *shortp;
-  register short *edge;
-  register short *states;
-  register short **new_includes;
-
-  includes = NEW2(ngotos, short *);
-  edge = NEW2(ngotos + 1, short);
-  states = NEW2(maxrhs + 1, short);
+      int stateno = to_state[i];
+      shifts *sp = states[stateno]->shifts;

 
 

-  for (i = 0; i < ngotos; i++)
-    {
-      nedges = 0;
-      state1 = from_state[i];
-      symbol1 = accessing_symbol[to_state[i]];
+      int j;
+      for (j = 0; j < sp->nshifts && SHIFT_IS_SHIFT (sp, j); j++)
+       bitset_set (F[i], SHIFT_SYMBOL (sp, j));

 
 

-      for (rulep = derives[symbol1]; *rulep > 0; rulep++)
+      for (; j < sp->nshifts; j++)

        {
        {

-         length = 1;
-         states[0] = state1;
-         stateno = state1;
-
-         for (rp = ritem + rrhs[*rulep]; *rp > 0; rp++)
-           {
-             symbol2 = *rp;
-             sp = shift_table[stateno];
-             k = sp->nshifts;
-
-             for (j = 0; j < k; j++)
-               {
-                 stateno = sp->shifts[j];
-                 if (accessing_symbol[stateno] == symbol2) break;
-               }
-
-             states[length++] = stateno;
-           }
-
-         if (!consistent[stateno])
-           add_lookback_edge(stateno, *rulep, i);
-
-         length--;
-         done = 0;
-         while (!done)
-           {
-             done = 1;
-             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);
-                 if (nullable[*rp]) done = 0;
-               }
-           }
+         token_number_t symbol = SHIFT_SYMBOL (sp, j);
+         if (nullable[symbol])
+           edge[nedges++] = map_goto (stateno, symbol);

        }
 
       if (nedges)
        {
        }
 
       if (nedges)
        {

-         includes[i] = shortp = NEW2(nedges + 1, short);
-         for (j = 0; j < nedges; j++)
-           shortp[j] = edge[j];
-         shortp[nedges] = -1;
+         reads[i] = XCALLOC (short, nedges + 1);
+         memcpy (reads[i], edge, nedges * sizeof (edge[0]));
+         reads[i][nedges] = -1;
+         nedges = 0;

        }
     }
 
        }
     }
 

-  new_includes = transpose(includes, ngotos);
+  digraph (reads);

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

-    if (includes[i])
-      FREE(includes[i]);
-
-  FREE(includes);
+    XFREE (reads[i]);

 
 

-  includes = new_includes;
-
-  FREE(edge);
-  FREE(states);
+  XFREE (reads);
+  XFREE (edge);

 }
 
 
 }
 
 

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

 {
 {

-  register int i;
-  register int k;
-  register int found;
-  register shorts *sp;
-
-  i = lookaheads[stateno];
-  k = lookaheads[stateno + 1];
-  found = 0;
-  while (!found && i < k)
-    {
-      if (LAruleno[i] == ruleno)
-       found = 1;
-      else
-       i++;
-    }
+  int i;
+  shorts *sp;

 
 

-  if (found == 0)
-    berror("add_lookback_edge");
+  for (i = 0; i < state->nlookaheads; ++i)
+    if (LArule[state->lookaheadsp + i]->number == ruleno)
+      break;

 
 

-  sp = NEW(shorts);
-  sp->next = lookback[i];
+  assert (LArule[state->lookaheadsp + i]->number == ruleno);
+
+  sp = XCALLOC (shorts, 1);
+  sp->next = lookback[state->lookaheadsp + i];

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

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

 }
 
 
 }
 
 

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

 {
 {

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

 
 

-  nedges = NEW2(n, short);
+  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 = NEW2(n, short *);
-  temp_R = NEW2(n, short *);
+  /* 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 = NEW2(k + 1, short);
-         new_R[i] = sp;
-         temp_R[i] = sp;
-         sp[k] = -1;
+         *end_R[R_arg[i][j]] = i;
+         ++end_R[R_arg[i][j]];

        }
        }

-    }

 
 

-  FREE(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);

     }
 
     }
 

-  FREE(temp_R);
-
-  return (new_R);
+  return new_R;

 }
 
 
 }
 
 

-void
-compute_FOLLOWS()
+static void
+build_relations (void)

 {
 {

-  register int i;
+  short *edge = XCALLOC (short, ngotos + 1);
+  short *states1 = XCALLOC (short, ritem_longest_rhs () + 1);
+  int i;

 
 

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

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

-      if (includes[i]) FREE(includes[i]);
-    }
+      int nedges = 0;
+      token_number_t symbol1 = states[to_state[i]]->accessing_symbol;
+      short *rulep;

 
 

-  FREE(includes);
-}
+      for (rulep = derives[symbol1]; *rulep > 0; rulep++)
+       {
+         int done;
+         int length = 1;
+         item_number_t *rp;
+         state_t *state = states[from_state[i]];
+         states1[0] = state->number;

 
 

+         for (rp = rules[*rulep].rhs; *rp >= 0; rp++)
+           {
+             shifts *sp = state->shifts;
+             int j;
+             for (j = 0; j < sp->nshifts; j++)
+               {
+                 state = states[sp->shifts[j]];
+                 if (state->accessing_symbol
+                     == item_number_as_token_number (*rp))
+                   break;
+               }

 
 

-void
-compute_lookaheads()
-{
-  register int i;
-  register int n;
-  register unsigned *fp1;
-  register unsigned *fp2;
-  register unsigned *fp3;
-  register shorts *sp;
-  register unsigned *rowp;
-/*   register short *rulep; JF unused */
-/*  register int count; JF unused */
-  register shorts *sptmp;/* JF */
-
-  rowp = LA;
-  n = lookaheads[nstates];
-  for (i = 0; i < n; i++)
-    {
-      fp3 = rowp + tokensetsize;
-      for (sp = lookback[i]; sp; sp = sp->next)
-       {
-         fp1 = rowp;
-         fp2 = F + tokensetsize * sp->value;
-         while (fp1 < fp3)
-           *fp1++ |= *fp2++;
+             states1[length++] = state->number;
+           }
+
+         if (!state->consistent)
+           add_lookback_edge (state, *rulep, i);
+
+         length--;
+         done = 0;
+         while (!done)
+           {
+             done = 1;
+             rp--;
+             /* JF added rp>=ritem &&   I hope to god its right! */
+             if (rp >= ritem && ISVAR (*rp))
+               {
+                 /* Downcasting from item_number_t to token_number_t. */
+                 edge[nedges++] = map_goto (states1[--length],
+                                            item_number_as_token_number (*rp));
+                 if (nullable[*rp])
+                   done = 0;
+               }
+           }

        }
 
        }
 

-      rowp = fp3;
+      if (nedges)
+       {
+         int j;
+         includes[i] = XCALLOC (short, nedges + 1);
+         for (j = 0; j < nedges; j++)
+           includes[i][j] = edge[j];
+         includes[i][nedges] = -1;
+       }

     }
 
     }
 

-  for (i = 0; i < n; i++)
-    {/* JF removed ref to freed storage */
-      for (sp = lookback[i]; sp; sp = sptmp) {
-       sptmp=sp->next;
-       FREE(sp);
-      }
-    }
+  XFREE (edge);
+  XFREE (states1);

 
 

-  FREE(lookback);
-  FREE(F);
+  includes = transpose (includes, ngotos);

 }
 
 
 }
 
 

-void
-digraph(relation)
-short **relation;
-{
-  register int i;
-
-  infinity = ngotos + 2;
-  INDEX = NEW2(ngotos + 1, short);
-  VERTICES = NEW2(ngotos + 1, short);
-  top = 0;

 
 

-  R = relation;
+static void
+compute_FOLLOWS (void)
+{
+  int i;

 
 

-  for (i = 0; i < ngotos; i++)
-    INDEX[i] = 0;
+  digraph (includes);

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

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

 
 

-  FREE(INDEX);
-  FREE(VERTICES);
+  XFREE (includes);

 }
 
 
 }
 
 

-void
-traverse(i)
-register int i;
+static void
+compute_lookaheads (void)

 {
 {

-  register unsigned *fp1;
-  register unsigned *fp2;
-  register unsigned *fp3;
-  register int j;
-  register short *rp;
+  size_t i;
+  shorts *sp;

 
 

-  int height;
-  unsigned *base;
-
-  VERTICES[++top] = i;
-  INDEX[i] = height = top;
+  for (i = 0; i < nLA; i++)
+    for (sp = lookback[i]; sp; sp = sp->next)
+      bitset_or (LA[i], LA[i], F[sp->value]);

 
 

-  base = F + i * tokensetsize;
-  fp3 = base + tokensetsize;
-
-  rp = R[i];
-  if (rp)
-    {
-      while ((j = *rp++) >= 0)
-       {
-         if (INDEX[j] == 0)
-           traverse(j);
+  /* Free LOOKBACK. */
+  for (i = 0; i < nLA; i++)
+    LIST_FREE (shorts, lookback[i]);

 
 

-         if (INDEX[i] > INDEX[j])
-           INDEX[i] = INDEX[j];
+  XFREE (lookback);
+  bitsetv_free (F);
+}

 
 

-         fp1 = base;
-         fp2 = F + j * tokensetsize;

 
 

-         while (fp1 < fp3)
-           *fp1++ |= *fp2++;
-       }
-    }
+/*--------------------------------------.
+| Initializing the lookaheads members.  |
+`--------------------------------------*/

 
 

-  if (INDEX[i] == height)
+static void
+initialize_lookaheads (void)
+{
+  size_t i;
+  nLA = 0;
+  for (i = 0; i < nstates; i++)

     {
     {

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

 
 

-         if (i == j)
+      for (k = 0; k < sp->nshifts; k++)
+       if (SHIFT_IS_ERROR (sp, k))
+         {
+           states[i]->consistent = 0;

            break;
            break;

+         }

 
 

-         fp1 = base;
-         fp2 = F + j * tokensetsize;
+      states[i]->nlookaheads = nlookaheads;
+      states[i]->lookaheadsp = nLA;
+      nLA += nlookaheads;
+    }
+}

 
 

-         while (fp1 < fp3)
-           *fp2++ = *fp1++;
-       }
+
+/*---------------------------------------.
+| 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)
+    {
+      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], k))
+           fprintf (out, "   on %d (%s) -> rule %d\n",
+                    k, quotearg_style (escape_quoting_style, symbols[k]->tag),
+                    LArule[states[i]->lookaheadsp + j]->number - 1);

     }
     }

+  fprintf (out, "Lookaheads: END\n");
+}
+
+void
+lalr (void)
+{
+  initialize_lookaheads ();
+  initialize_LA ();
+  set_goto_map ();
+  initialize_F ();
+  build_relations ();
+  compute_FOLLOWS ();
+  compute_lookaheads ();
+
+  if (trace_flag)
+    lookaheads_print (stderr);

 }
 }