Copy BYacc's nice way to report the grammar.

[bison.git] / src / LR0.c

diff --git a/src/LR0.c b/src/LR0.c
index 1ed8e92ce4bd73c73612d7929503b08acbc5edb3..95200d53d8b27f1f5869cece72912e4bbd42f17c 100644 (file)
--- a/src/LR0.c
+++ b/src/LR0.c
@@ -1,119 +1,101 @@
 /* Generate the nondeterministic finite state machine for bison,
 /* Generate the nondeterministic finite state machine for bison,

-   Copyright (C) 1984, 1986, 1989 Free Software Foundation, Inc.
+   Copyright 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, Inc., 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, 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.  */

 
 
 /* See comments in state.h for the data structures that represent it.
    The entry point is generate_states.  */
 
 
 
 /* See comments in state.h for the data structures that represent it.
    The entry point is generate_states.  */
 

-#include <stdio.h>

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

-#include "machine.h"
-#include "alloc.h"
+#include "bitset.h"
+#include "quotearg.h"
+#include "symtab.h"
+#include "gram.h"
+#include "getargs.h"
+#include "reader.h"

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

-
-
-extern char *nullable;
-extern short *itemset;
-extern short *itemsetend;
-
-
-int nstates;
-int final_state;
-core *first_state;
-shifts *first_shift;
-reductions *first_reduction;
-
-int get_state PARAMS((int));
-core *new_state PARAMS((int));
-
-void allocate_itemsets PARAMS((void));
-void allocate_storage PARAMS((void));
-void free_storage PARAMS((void));
-void generate_states PARAMS((void));
-void new_itemsets PARAMS((void));
-void append_states PARAMS((void));
-void initialize_states PARAMS((void));
-void save_shifts PARAMS((void));
-void save_reductions PARAMS((void));
-void augment_automaton PARAMS((void));
-void insert_start_shift PARAMS((void));
-extern void initialize_closure PARAMS((int));
-extern void closure PARAMS((short *, int));
-extern void finalize_closure PARAMS((void));
-extern void toomany PARAMS((char *));
-
-static core *this_state;
-static core *last_state;
-static shifts *last_shift;
-static reductions *last_reduction;
+#include "complain.h"
+#include "closure.h"
+#include "LR0.h"
+#include "lalr.h"
+#include "reduce.h"
+
+unsigned int nstates = 0;
+/* Initialize the final state to -1, otherwise, it might be set to 0
+   by default, and since we don't compute the reductions of the final
+   state, we end up not computing the reductions of the initial state,
+   which is of course needed.
+
+   FINAL_STATE is properly set by new_state when it recognizes the
+   accessing symbol: EOF.  */
+int final_state = -1;
+static state_t *first_state = NULL;
+
+static state_t *this_state = NULL;
+static state_t *last_state = NULL;

 
 static int nshifts;
 
 static int nshifts;

-static short *shift_symbol;
+static symbol_number_t *shift_symbol = NULL;

 
 

-static short *redset;
-static short *shiftset;
+static short *redset = NULL;
+static short *shiftset = NULL;

 
 

-static short **kernel_base;
-static short **kernel_end;
-static short *kernel_items;
+static item_number_t **kernel_base = NULL;
+static int *kernel_size = NULL;
+static item_number_t *kernel_items = NULL;

 
 /* hash table for states, to recognize equivalent ones.  */
 
 
 /* hash table for states, to recognize equivalent ones.  */
 

-#define        STATE_TABLE_SIZE        1009
-static core **state_table;
+#define        STATE_HASH_SIZE 1009
+static state_t **state_hash = NULL;

 
 

-
-
-void
+\f
+static void

 allocate_itemsets (void)
 {
 allocate_itemsets (void)
 {

-  register short *itemp;
-  register int symbol;
-  register int i;
-  register int count;
-  register short *symbol_count;
-
-  count = 0;
-  symbol_count = NEW2(nsyms, short);
-
-  itemp = ritem;
-  symbol = *itemp++;
-  while (symbol)
-    {
-      if (symbol > 0)
-       {
-         count++;
-         symbol_count[symbol]++;
-       }
-      symbol = *itemp++;
-    }
-
-  /* see comments before new_itemsets.  All the vectors of items
-     live inside kernel_items.  The number of active items after
+  int i, r;
+  item_number_t *rhsp;
+
+  /* Count the number of occurrences of all the symbols in RITEMS.
+     Note that useless productions (hence useless nonterminals) are
+     browsed too, hence we need to allocate room for _all_ the
+     symbols.  */
+  int count = 0;
+  short *symbol_count = XCALLOC (short, nsyms + nuseless_nonterminals);
+
+  for (r = 1; r < nrules + 1; ++r)
+    for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp)
+      {
+       count++;
+       symbol_count[*rhsp]++;
+      }
+
+  /* See comments before new_itemsets.  All the vectors of items
+     live inside KERNEL_ITEMS.  The number of active items after

      some symbol cannot be more than the number of times that symbol
      appears as an item, which is symbol_count[symbol].
      We allocate that much space for each symbol.  */
 
      some symbol cannot be more than the number of times that symbol
      appears as an item, which is symbol_count[symbol].
      We allocate that much space for each symbol.  */
 

-  kernel_base = NEW2(nsyms, short *);
-  kernel_items = NEW2(count, short);
+  kernel_base = XCALLOC (item_number_t *, nsyms);
+  if (count)
+    kernel_items = XCALLOC (item_number_t, count);

 
   count = 0;
   for (i = 0; i < nsyms; i++)
 
   count = 0;
   for (i = 0; i < nsyms; i++)


@@ -122,216 +104,160 @@ allocate_itemsets (void)
       count += symbol_count[i];
     }
 
       count += symbol_count[i];
     }
 

-  shift_symbol = symbol_count;
-  kernel_end = NEW2(nsyms, short *);
+  free (symbol_count);
+  kernel_size = XCALLOC (int, nsyms);

 }
 
 
 }
 
 

-void
+static void

 allocate_storage (void)
 {
 allocate_storage (void)
 {

-  allocate_itemsets();
+  allocate_itemsets ();

 
 

-  shiftset = NEW2(nsyms, short);
-  redset = NEW2(nrules + 1, short);
-  state_table = NEW2(STATE_TABLE_SIZE, core *);
+  shiftset = XCALLOC (short, nsyms);
+  redset = XCALLOC (short, nrules + 1);
+  state_hash = XCALLOC (state_t *, STATE_HASH_SIZE);
+  shift_symbol = XCALLOC (symbol_number_t, nsyms);

 }
 
 
 }
 
 

-void
+static void

 free_storage (void)
 {
 free_storage (void)
 {

-  FREE(shift_symbol);
-  FREE(redset);
-  FREE(shiftset);
-  FREE(kernel_base);
-  FREE(kernel_end);
-  FREE(kernel_items);
-  FREE(state_table);
+  free (shift_symbol);
+  free (redset);
+  free (shiftset);
+  free (kernel_base);
+  free (kernel_size);
+  XFREE (kernel_items);
+  free (state_hash);

 }
 
 
 
 }
 
 
 

-/* compute the nondeterministic finite state machine (see state.h for details)
-from the grammar.  */
-void
-generate_states (void)
-{
-  allocate_storage();
-  initialize_closure(nitems);
-  initialize_states();
-
-  while (this_state)
-    {
-      /* Set up ruleset and itemset for the transitions out of this state.
-         ruleset gets a 1 bit for each rule that could reduce now.
-        itemset gets a vector of all the items that could be accepted next.  */
-      closure(this_state->items, this_state->nitems);
-      /* record the reductions allowed out of this state */
-      save_reductions();
-      /* find the itemsets of the states that shifts can reach */
-      new_itemsets();
-      /* find or create the core structures for those states */
-      append_states();
-
-      /* create the shifts structures for the shifts to those states,
-         now that the state numbers transitioning to are known */
-      if (nshifts > 0)
-        save_shifts();
-
-      /* states are queued when they are created; process them all */
-      this_state = this_state->next;
-    }

 
 

-  /* discard various storage */
-  finalize_closure();
-  free_storage();
+/*----------------------------------------------------------------.
+| Find which symbols can be shifted in the current state, and for |
+| each one record which items would be active after that shift.   |
+| Uses the contents of itemset.                                   |
+|                                                                 |
+| shift_symbol is set to a vector of the symbols that can be      |
+| shifted.  For each symbol in the grammar, kernel_base[symbol]   |
+| points to a vector of item numbers activated if that symbol is  |
+| shifted, and kernel_size[symbol] is their numbers.              |
+`----------------------------------------------------------------*/

 
 

-  /* set up initial and final states as parser wants them */
-  augment_automaton();
-}
-
-
-
-/* Find which symbols can be shifted in the current state,
-   and for each one record which items would be active after that shift.
-   Uses the contents of itemset.
-   shift_symbol is set to a vector of the symbols that can be shifted.
-   For each symbol in the grammar, kernel_base[symbol] points to
-   a vector of item numbers activated if that symbol is shifted,
-   and kernel_end[symbol] points after the end of that vector.  */
-void
+static void

 new_itemsets (void)
 {
 new_itemsets (void)
 {

-  register int i;
-  register int shiftcount;
-  register short *isp;
-  register short *ksp;
-  register int symbol;
+  int i;

 
 

-#ifdef TRACE
-  fprintf(stderr, "Entering new_itemsets\n");
-#endif
+  if (trace_flag)
+    fprintf (stderr, "Entering new_itemsets, state = %d\n",
+            this_state->number);

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

-    kernel_end[i] = NULL;
-
-  shiftcount = 0;
-
-  isp = itemset;
+    kernel_size[i] = 0;
+
+  nshifts = 0;
+
+  for (i = 0; i < nritemset; ++i)
+    if (ritem[itemset[i]] >= 0)
+      {
+       symbol_number_t symbol
+         = item_number_as_symbol_number (ritem[itemset[i]]);
+       if (!kernel_size[symbol])
+         {
+           shift_symbol[nshifts] = symbol;
+           nshifts++;
+         }
+
+       kernel_base[symbol][kernel_size[symbol]] = itemset[i] + 1;
+       kernel_size[symbol]++;
+      }
+}

 
 

-  while (isp < itemsetend)
-    {
-      i = *isp++;
-      symbol = ritem[i];
-      if (symbol > 0)
-       {
-          ksp = kernel_end[symbol];

 
 

-          if (!ksp)
-           {
-             shift_symbol[shiftcount++] = symbol;
-             ksp = kernel_base[symbol];
-           }

 
 

-          *ksp++ = i + 1;
-          kernel_end[symbol] = ksp;
-       }
-    }
+/*-----------------------------------------------------------------.
+| Subroutine of get_state.  Create a new state for those items, if |
+| necessary.                                                       |
+`-----------------------------------------------------------------*/

 
 

-  nshifts = shiftcount;
-}
+static state_t *
+new_state (symbol_number_t symbol, size_t core_size, item_number_t *core)
+{
+  state_t *p;

 
 

+  if (trace_flag)
+    fprintf (stderr, "Entering new_state, state = %d, symbol = %d (%s)\n",
+            nstates, symbol, symbol_tag_get (symbols[symbol]));

 
 

+  if (nstates >= SHRT_MAX)
+    fatal (_("too many states (max %d)"), SHRT_MAX);

 
 

-/* Use the information computed by new_itemsets to find the state numbers
-   reached by each shift transition from the current state.
+  p = STATE_ALLOC (core_size);
+  p->accessing_symbol = symbol;
+  p->number = nstates;
+  p->solved_conflicts = NULL;

 
 

-   shiftset is set up as a vector of state numbers of those states.  */
-void
-append_states (void)
-{
-  register int i;
-  register int j;
-  register int symbol;
+  p->nitems = core_size;
+  memcpy (p->items, core, core_size * sizeof (core[0]));

 
 

-#ifdef TRACE
-  fprintf(stderr, "Entering append_states\n");
-#endif
+  /* If this is the eoftoken, and this is not the initial state, then
+     this is the final state.  */
+  if (symbol == 0 && first_state)
+    final_state = p->number;

 
 

-  /* first sort shift_symbol into increasing order */
+  if (!first_state)
+    first_state = p;
+  if (last_state)
+    last_state->next = p;
+  last_state = p;

 
 

-  for (i = 1; i < nshifts; i++)
-    {
-      symbol = shift_symbol[i];
-      j = i;
-      while (j > 0 && shift_symbol[j - 1] > symbol)
-       {
-         shift_symbol[j] = shift_symbol[j - 1];
-         j--;
-       }
-      shift_symbol[j] = symbol;
-    }
+  nstates++;

 
 

-  for (i = 0; i < nshifts; i++)
-    {
-      symbol = shift_symbol[i];
-      shiftset[i] = get_state(symbol);
-    }
+  return p;

 }
 
 
 }
 
 

+/*--------------------------------------------------------------.
+| Find the state number for the state we would get to (from the |
+| current state) by shifting symbol.  Create a new state if no  |
+| equivalent one exists already.  Used by append_states.        |
+`--------------------------------------------------------------*/

 
 

-/* find the state number for the state we would get to
-(from the current state) by shifting symbol.
-Create a new state if no equivalent one exists already.
-Used by append_states  */
-
-int
-get_state (int symbol)
+static int
+get_state (symbol_number_t symbol, size_t core_size, item_number_t *core)

 {
 {

-  register int key;
-  register short *isp1;
-  register short *isp2;
-  register short *iend;
-  register core *sp;
-  register int found;
-
-  int n;
+  int key;
+  size_t i;
+  state_t *sp;

 
 

-#ifdef TRACE
-  fprintf(stderr, "Entering get_state, symbol = %d\n", symbol);
-#endif
+  if (trace_flag)
+    fprintf (stderr, "Entering get_state, state = %d, symbol = %d (%s)\n",
+            this_state->number, symbol,
+            symbol_tag_get (symbols[symbol]));

 
 

-  isp1 = kernel_base[symbol];
-  iend = kernel_end[symbol];
-  n = iend - isp1;
-
-  /* add up the target state's active item numbers to get a hash key */
+  /* Add up the target state's active item numbers to get a hash key.
+     */

   key = 0;
   key = 0;

-  while (isp1 < iend)
-    key += *isp1++;
-
-  key = key % STATE_TABLE_SIZE;
-
-  sp = state_table[key];
+  for (i = 0; i < core_size; ++i)
+    key += core[i];
+  key = key % STATE_HASH_SIZE;
+  sp = state_hash[key];

 
   if (sp)
     {
 
   if (sp)
     {

-      found = 0;
+      int found = 0;

       while (!found)
        {
       while (!found)
        {

-         if (sp->nitems == n)
+         if (sp->nitems == core_size)

            {
              found = 1;
            {
              found = 1;

-             isp1 = kernel_base[symbol];
-             isp2 = sp->items;
-
-             while (found && isp1 < iend)
-               {
-                 if (*isp1++ != *isp2++)
-                   found = 0;
-               }
+             for (i = 0; i < core_size; ++i)
+               if (core[i] != sp->items[i])
+                 found = 0;

            }
 
          if (!found)
            }
 
          if (!found)


@@ -340,368 +266,188 @@ get_state (int symbol)
                {
                  sp = sp->link;
                }
                {
                  sp = sp->link;
                }

-             else   /* bucket exhausted and no match */
+             else              /* bucket exhausted and no match */

                {
                {

-                 sp = sp->link = new_state(symbol);
+                 sp = sp->link = new_state (symbol, core_size, core);

                  found = 1;
                }
            }
        }
     }
                  found = 1;
                }
            }
        }
     }

-  else      /* bucket is empty */
+  else                         /* bucket is empty */

     {
     {

-      state_table[key] = sp = new_state(symbol);
+      state_hash[key] = sp = new_state (symbol, core_size, core);

     }
 
     }
 

-  return (sp->number);
-}
-
+  if (trace_flag)
+    fprintf (stderr, "Exiting get_state => %d\n", sp->number);

 
 

+  return sp->number;
+}

 
 

-/* subroutine of get_state.  create a new state for those items, if necessary.  */
+/*------------------------------------------------------------------.
+| Use the information computed by new_itemsets to find the state    |
+| numbers reached by each shift transition from the current state.  |
+|                                                                   |
+| shiftset is set up as a vector of state numbers of those states.  |
+`------------------------------------------------------------------*/

 
 

-core *
-new_state (int symbol)
+static void
+append_states (void)

 {
 {

-  register int n;
-  register core *p;
-  register short *isp1;
-  register short *isp2;
-  register short *iend;
-
-#ifdef TRACE
-  fprintf(stderr, "Entering new_state, symbol = %d\n", symbol);
-#endif
-
-  if (nstates >= MAXSHORT)
-    toomany("states");
+  int i;
+  int j;
+  symbol_number_t symbol;

 
 

-  isp1 = kernel_base[symbol];
-  iend = kernel_end[symbol];
-  n = iend - isp1;
+  if (trace_flag)
+    fprintf (stderr, "Entering append_states, state = %d\n",
+            this_state->number);

 
 

-  p = (core *) xmalloc((unsigned) (sizeof(core) + (n - 1) * sizeof(short)));
-  p->accessing_symbol = symbol;
-  p->number = nstates;
-  p->nitems = n;
-
-  isp2 = p->items;
-  while (isp1 < iend)
-    *isp2++ = *isp1++;
-
-  last_state->next = p;
-  last_state = p;
+  /* first sort shift_symbol into increasing order */

 
 

-  nstates++;
+  for (i = 1; i < nshifts; i++)
+    {
+      symbol = shift_symbol[i];
+      j = i;
+      while (j > 0 && shift_symbol[j - 1] > symbol)
+       {
+         shift_symbol[j] = shift_symbol[j - 1];
+         j--;
+       }
+      shift_symbol[j] = symbol;
+    }

 
 

-  return (p);
+  for (i = 0; i < nshifts; i++)
+    {
+      symbol = shift_symbol[i];
+      shiftset[i] = get_state (symbol,
+                              kernel_size[symbol], kernel_base[symbol]);
+    }

 }
 
 
 }
 
 

-void
-initialize_states (void)
+static void
+new_states (void)

 {
 {

-  register core *p;
-/*  register unsigned *rp1; JF unused */
-/*  register unsigned *rp2; JF unused */
-/*  register unsigned *rend; JF unused */
-
-  p = (core *) xmalloc((unsigned) (sizeof(core) - sizeof(short)));
-  first_state = last_state = this_state = p;
-  nstates = 1;
+  /* The 0 at the lhs is the index of the item of this initial rule.  */
+  kernel_base[0][0] = 0;
+  kernel_size[0] = 1;
+  this_state = new_state (0, kernel_size[0], kernel_base[0]);

 }
 
 
 }
 
 

-void
+/*------------------------------------------------------------.
+| Save the NSHIFTS of SHIFTSET into the current linked list.  |
+`------------------------------------------------------------*/
+
+static void

 save_shifts (void)
 {
 save_shifts (void)
 {

-  register shifts *p;
-  register short *sp1;
-  register short *sp2;
-  register short *send;
-
-  p = (shifts *) xmalloc((unsigned) (sizeof(shifts) +
-                                    (nshifts - 1) * sizeof(short)));
-
-  p->number = this_state->number;
-  p->nshifts = nshifts;
-
-  sp1 = shiftset;
-  sp2 = p->shifts;
-  send = shiftset + nshifts;
-
-  while (sp1 < send)
-    *sp2++ = *sp1++;
-
-  if (last_shift)
-    {
-      last_shift->next = p;
-      last_shift = p;
-    }
-  else
-    {
-      first_shift = p;
-      last_shift = p;
-    }
+  shifts *p = shifts_new (nshifts);
+  memcpy (p->shifts, shiftset, nshifts * sizeof (shiftset[0]));
+  this_state->shifts = p;

 }
 
 
 }
 
 

+/*----------------------------------------------------------------.
+| Find which rules can be used for reduction transitions from the |
+| current state and make a reductions structure for the state to  |
+| record their rule numbers.                                      |
+`----------------------------------------------------------------*/

 
 

-/* find which rules can be used for reduction transitions from the current state
-   and make a reductions structure for the state to record their rule numbers.  */
-void
+static void

 save_reductions (void)
 {
 save_reductions (void)
 {

-  register short *isp;
-  register short *rp1;
-  register short *rp2;
-  register int item;
-  register int count;
-  register reductions *p;
-
-  short *rend;
+  int count = 0;
+  int i;

 
 

-  /* find and count the active items that represent ends of rules */
+  /* If this is the final state, we want it to have no reductions at
+     all, although it has one for `START_SYMBOL EOF .'.  */
+  if (this_state->number == final_state)
+    return;

 
 

-  count = 0;
-  for (isp = itemset; isp < itemsetend; isp++)
+  /* Find and count the active items that represent ends of rules. */
+  for (i = 0; i < nritemset; ++i)

     {
     {

-      item = ritem[*isp];
+      int item = ritem[itemset[i]];

       if (item < 0)
       if (item < 0)

-       {
-         redset[count++] = -item;
-       }
+       redset[count++] = -item;

     }
 
     }
 

-  /* make a reductions structure and copy the data into it.  */
-
-  if (count)
-    {
-      p = (reductions *) xmalloc((unsigned) (sizeof(reductions) +
-                                            (count - 1) * sizeof(short)));
-
-      p->number = this_state->number;
-      p->nreds = count;
-
-      rp1 = redset;
-      rp2 = p->rules;
-      rend = rp1 + count;
-
-      while (rp1 < rend)
-       *rp2++ = *rp1++;
-
-      if (last_reduction)
-       {
-         last_reduction->next = p;
-         last_reduction = p;
-       }
-      else
-       {
-         first_reduction = p;
-         last_reduction = p;
-       }
-    }
+  /* Make a reductions structure and copy the data into it.  */
+  this_state->reductions = reductions_new (count);
+  memcpy (this_state->reductions->rules, redset, count * sizeof (redset[0]));

 }
 
 }
 

+\f
+/*---------------.
+| Build STATES.  |
+`---------------*/

 
 

-
-/* Make sure that the initial state has a shift that accepts the
-grammar's start symbol and goes to the next-to-final state,
-which has a shift going to the final state, which has a shift
-to the termination state.
-Create such states and shifts if they don't happen to exist already.  */
-void
-augment_automaton (void)
+static void
+set_states (void)

 {
 {

-  register int i;
-  register int k;
-/*  register int found; JF unused */
-  register core *statep;
-  register shifts *sp;
-  register shifts *sp2;
-  register shifts *sp1 = NULL;
-
-  sp = first_shift;
-
-  if (sp)
-    {
-      if (sp->number == 0)
-       {
-         k = sp->nshifts;
-         statep = first_state->next;
-
-         /* The states reached by shifts from first_state are numbered 1...K.
-            Look for one reached by start_symbol.  */
-         while (statep->accessing_symbol < start_symbol
-                 && statep->number < k)
-           statep = statep->next;
-
-         if (statep->accessing_symbol == start_symbol)
-           {
-             /* We already have a next-to-final state.
-                Make sure it has a shift to what will be the final state.  */
-             k = statep->number;
-
-             while (sp && sp->number < k)
-               {
-                 sp1 = sp;
-                 sp = sp->next;
-               }
-
-             if (sp && sp->number == k)
-               {
-                 sp2 = (shifts *) xmalloc((unsigned) (sizeof(shifts)
-                                                      + sp->nshifts * sizeof(short)));
-                 sp2->number = k;
-                 sp2->nshifts = sp->nshifts + 1;
-                 sp2->shifts[0] = nstates;
-                 for (i = sp->nshifts; i > 0; i--)
-                   sp2->shifts[i] = sp->shifts[i - 1];
-
-                 /* Patch sp2 into the chain of shifts in place of sp,
-                    following sp1.  */
-                 sp2->next = sp->next;
-                 sp1->next = sp2;
-                 if (sp == last_shift)
-                   last_shift = sp2;
-                 FREE(sp);
-               }
-             else
-               {
-                 sp2 = NEW(shifts);
-                 sp2->number = k;
-                 sp2->nshifts = 1;
-                 sp2->shifts[0] = nstates;
-
-                 /* Patch sp2 into the chain of shifts between sp1 and sp.  */
-                 sp2->next = sp;
-                 sp1->next = sp2;
-                 if (sp == 0)
-                   last_shift = sp2;
-               }
-           }
-         else
-           {
-             /* There is no next-to-final state as yet.  */
-             /* Add one more shift in first_shift,
-                going to the next-to-final state (yet to be made).  */
-             sp = first_shift;
-
-             sp2 = (shifts *) xmalloc(sizeof(shifts)
-                                        + sp->nshifts * sizeof(short));
-             sp2->nshifts = sp->nshifts + 1;
-
-             /* Stick this shift into the vector at the proper place.  */
-             statep = first_state->next;
-             for (k = 0, i = 0; i < sp->nshifts; k++, i++)
-               {
-                 if (statep->accessing_symbol > start_symbol && i == k)
-                   sp2->shifts[k++] = nstates;
-                 sp2->shifts[k] = sp->shifts[i];
-                 statep = statep->next;
-               }
-             if (i == k)
-               sp2->shifts[k++] = nstates;
-
-             /* Patch sp2 into the chain of shifts
-                in place of sp, at the beginning.  */
-             sp2->next = sp->next;
-             first_shift = sp2;
-             if (last_shift == sp)
-               last_shift = sp2;
+  state_t *sp;
+  states = XCALLOC (state_t *, nstates);

 
 

-             FREE(sp);
-
-             /* Create the next-to-final state, with shift to
-                what will be the final state.  */
-             insert_start_shift();
-           }
-       }
-      else
-       {
-         /* The initial state didn't even have any shifts.
-            Give it one shift, to the next-to-final state.  */
-         sp = NEW(shifts);
-         sp->nshifts = 1;
-         sp->shifts[0] = nstates;
-
-         /* Patch sp into the chain of shifts at the beginning.  */
-         sp->next = first_shift;
-         first_shift = sp;
-
-         /* Create the next-to-final state, with shift to
-            what will be the final state.  */
-         insert_start_shift();
-       }
-    }
-  else
+  for (sp = first_state; sp; sp = sp->next)

     {
     {

-      /* There are no shifts for any state.
-        Make one shift, from the initial state to the next-to-final state.  */
-
-      sp = NEW(shifts);
-      sp->nshifts = 1;
-      sp->shifts[0] = nstates;
-
-      /* Initialize the chain of shifts with sp.  */
-      first_shift = sp;
-      last_shift = sp;
-
-      /* Create the next-to-final state, with shift to
-        what will be the final state.  */
-      insert_start_shift();
+      /* Pessimization, but simplification of the code: make sure all
+        the states have a shifts, errs, and reductions, even if
+        reduced to 0.  */
+      if (!sp->shifts)
+       sp->shifts = shifts_new (0);
+      if (!sp->errs)
+       sp->errs = errs_new (0);
+      if (!sp->reductions)
+       sp->reductions = reductions_new (0);
+
+      states[sp->number] = sp;

     }
     }

-
-  /* Make the final state--the one that follows a shift from the
-     next-to-final state.
-     The symbol for that shift is 0 (end-of-file).  */
-  statep = (core *) xmalloc((unsigned) (sizeof(core) - sizeof(short)));
-  statep->number = nstates;
-  last_state->next = statep;
-  last_state = statep;
-
-  /* Make the shift from the final state to the termination state.  */
-  sp = NEW(shifts);
-  sp->number = nstates++;
-  sp->nshifts = 1;
-  sp->shifts[0] = nstates;
-  last_shift->next = sp;
-  last_shift = sp;
-
-  /* Note that the variable `final_state' refers to what we sometimes call
-     the termination state.  */
-  final_state = nstates;
-
-  /* Make the termination state.  */
-  statep = (core *) xmalloc((unsigned) (sizeof(core) - sizeof(short)));
-  statep->number = nstates++;
-  last_state->next = statep;
-  last_state = statep;

 }
 
 }
 

+/*-------------------------------------------------------------------.
+| Compute the nondeterministic finite state machine (see state.h for |
+| details) from the grammar.                                         |
+`-------------------------------------------------------------------*/

 
 

-/* subroutine of augment_automaton.
-   Create the next-to-final state, to which a shift has already been made in
-   the initial state.  */

 void
 void

-insert_start_shift (void)
+generate_states (void)

 {
 {

-  register core *statep;
-  register shifts *sp;
+  allocate_storage ();
+  new_closure (nritems);
+  new_states ();

 
 

-  statep = (core *) xmalloc((unsigned) (sizeof(core) - sizeof(short)));
-  statep->number = nstates;
-  statep->accessing_symbol = start_symbol;
+  while (this_state)
+    {
+      if (trace_flag)
+       fprintf (stderr, "Processing state %d (reached by %s)\n",
+                this_state->number,
+                symbol_tag_get (symbols[this_state->accessing_symbol]));
+      /* Set up ruleset and itemset for the transitions out of this
+         state.  ruleset gets a 1 bit for each rule that could reduce
+         now.  itemset gets a vector of all the items that could be
+         accepted next.  */
+      closure (this_state->items, this_state->nitems);
+      /* record the reductions allowed out of this state */
+      save_reductions ();
+      /* find the itemsets of the states that shifts can reach */
+      new_itemsets ();
+      /* find or create the core structures for those states */
+      append_states ();

 
 

-  last_state->next = statep;
-  last_state = statep;
+      /* create the shifts structures for the shifts to those states,
+         now that the state numbers transitioning to are known */
+      save_shifts ();

 
 

-  /* Make a shift from this state to (what will be) the final state.  */
-  sp = NEW(shifts);
-  sp->number = nstates++;
-  sp->nshifts = 1;
-  sp->shifts[0] = nstates;
+      /* states are queued when they are created; process them all */
+      this_state = this_state->next;
+    }
+
+  /* discard various storage */
+  free_closure ();
+  free_storage ();

 
 

-  last_shift->next = sp;
-  last_shift = sp;
+  /* Set up STATES. */
+  set_states ();

 }
 }