X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/6986fd9e3b0af45d17e709525587877871212bba..e2a8c0f591c1f8ca0909faee23914f62bacb866c:/src/LR0.c

diff --git a/src/LR0.c b/src/LR0.c
index 3288d9dc..259b8912 100644
--- a/src/LR0.c
+++ b/src/LR0.c
@@ -1,5 +1,7 @@
-/* Generate the nondeterministic finite state machine for bison,
-   Copyright 1984, 1986, 1989, 2000 Free Software Foundation, Inc.
+/* Generate the nondeterministic finite state machine for Bison.
+
+   Copyright (C) 1984, 1986, 1989, 2000, 2001, 2002, 2004, 2005 Free
+   Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -15,81 +17,109 @@
 
    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.  */
+   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.  */
 
 
 /* See comments in state.h for the data structures that represent it.
    The entry point is generate_states.  */
 
+#include <config.h>
 #include "system.h"
+
+#include <bitset.h>
+#include <quotearg.h>
+
+#include "LR0.h"
+#include "closure.h"
+#include "complain.h"
+#include "getargs.h"
+#include "gram.h"
 #include "gram.h"
+#include "lalr.h"
+#include "reader.h"
+#include "reduce.h"
 #include "state.h"
-#include "complain.h"
-#include "closure.h"
-#include "LR0.h"
+#include "symtab.h"
 
+typedef struct state_list
+{
+  struct state_list *next;
+  state *state;
+} state_list;
 
-int nstates;
-int final_state;
-core *first_state = NULL;
-shifts *first_shift = NULL;
-reductions *first_reduction = NULL;
+static state_list *first_state = NULL;
+static state_list *last_state = NULL;
 
-static core *this_state = NULL;
-static core *last_state = NULL;
-static shifts *last_shift = NULL;
-static reductions *last_reduction = NULL;
 
-static int nshifts;
-static short *shift_symbol = NULL;
+/*------------------------------------------------------------------.
+| A state was just discovered from another state.  Queue it for     |
+| later examination, in order to find its transitions.  Return it.  |
+`------------------------------------------------------------------*/
+
+static state *
+state_list_append (symbol_number sym, size_t core_size, item_number *core)
+{
+  state_list *node = xmalloc (sizeof *node);
+  state *s = state_new (sym, core_size, core);
+
+  if (trace_flag & trace_automaton)
+    fprintf (stderr, "state_list_append (state = %d, symbol = %d (%s))\n",
+	     nstates, sym, symbols[sym]->tag);
 
-static short *redset = NULL;
-static short *shiftset = NULL;
+  node->next = NULL;
+  node->state = s;
 
-static short **kernel_base = NULL;
-static short **kernel_end = NULL;
-static short *kernel_items = NULL;
+  if (!first_state)
+    first_state = node;
+  if (last_state)
+    last_state->next = node;
+  last_state = node;
 
-/* hash table for states, to recognize equivalent ones.  */
+  return s;
+}
+
+static int nshifts;
+static symbol_number *shift_symbol;
 
-#define	STATE_TABLE_SIZE	1009
-static core **state_table = NULL;
+static rule **redset;
+static state **shiftset;
+
+static item_number **kernel_base;
+static int *kernel_size;
+static item_number *kernel_items;
 
 
 static void
 allocate_itemsets (void)
 {
-  short *itemp = NULL;
-  int symbol;
-  int i;
-  int count;
-  short *symbol_count = NULL;
-
-  count = 0;
-  symbol_count = XCALLOC (short, nsyms);
-
-  itemp = ritem;
-  symbol = *itemp++;
-  while (symbol)
-    {
-      if (symbol > 0)
-	{
-	  count++;
-	  symbol_count[symbol]++;
-	}
-      symbol = *itemp++;
-    }
+  symbol_number i;
+  rule_number r;
+  item_number *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.  */
+  size_t count = 0;
+  size_t *symbol_count = xcalloc (nsyms + nuseless_nonterminals,
+				  sizeof *symbol_count);
+
+  for (r = 0; r < nrules; ++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].
+     some symbol S cannot be more than the number of times that S
+     appears as an item, which is SYMBOL_COUNT[S].
      We allocate that much space for each symbol.  */
 
-  kernel_base = XCALLOC (short *, nsyms);
-  if (count)
-    kernel_items = XCALLOC (short, count);
+  kernel_base = xnmalloc (nsyms, sizeof *kernel_base);
+  kernel_items = xnmalloc (count, sizeof *kernel_items);
 
   count = 0;
   for (i = 0; i < nsyms; i++)
@@ -98,8 +128,8 @@ allocate_itemsets (void)
       count += symbol_count[i];
     }
 
-  shift_symbol = symbol_count;
-  kernel_end = XCALLOC (short *, nsyms);
+  free (symbol_count);
+  kernel_size = xnmalloc (nsyms, sizeof *kernel_size);
 }
 
 
@@ -108,555 +138,194 @@ allocate_storage (void)
 {
   allocate_itemsets ();
 
-  shiftset = XCALLOC (short, nsyms);
-  redset = XCALLOC (short, nrules + 1);
-  state_table = XCALLOC (core *, STATE_TABLE_SIZE);
+  shiftset = xnmalloc (nsyms, sizeof *shiftset);
+  redset = xnmalloc (nrules, sizeof *redset);
+  state_hash_new ();
+  shift_symbol = xnmalloc (nsyms, sizeof *shift_symbol);
 }
 
 
 static void
 free_storage (void)
 {
-  XFREE (shift_symbol);
-  XFREE (redset);
-  XFREE (shiftset);
-  XFREE (kernel_base);
-  XFREE (kernel_end);
-  XFREE (kernel_items);
-  XFREE (state_table);
+  free (shift_symbol);
+  free (redset);
+  free (shiftset);
+  free (kernel_base);
+  free (kernel_size);
+  free (kernel_items);
+  state_hash_free ();
 }
 
 
 
 
-/*----------------------------------------------------------------.
-| 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.                                                         |
-`----------------------------------------------------------------*/
+/*---------------------------------------------------------------.
+| Find which symbols can be shifted in S, 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.             |
+`---------------------------------------------------------------*/
 
 static void
-new_itemsets (void)
+new_itemsets (state *s)
 {
-  int i;
-  int shiftcount;
-  short *isp;
-  short *ksp;
-  int symbol;
-
-#if TRACE
-  fprintf (stderr, "Entering new_itemsets\n");
-#endif
-
-  for (i = 0; i < nsyms; i++)
-    kernel_end[i] = NULL;
+  size_t i;
 
-  shiftcount = 0;
+  if (trace_flag & trace_automaton)
+    fprintf (stderr, "Entering new_itemsets, state = %d\n", s->number);
 
-  isp = itemset;
+  memset (kernel_size, 0, nsyms * sizeof *kernel_size);
 
-  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];
-	    }
+  nshifts = 0;
 
-	  *ksp++ = i + 1;
-	  kernel_end[symbol] = ksp;
-	}
-    }
+  for (i = 0; i < nritemset; ++i)
+    if (ritem[itemset[i]] >= 0)
+      {
+	symbol_number sym = item_number_as_symbol_number (ritem[itemset[i]]);
+	if (!kernel_size[sym])
+	  {
+	    shift_symbol[nshifts] = sym;
+	    nshifts++;
+	  }
 
-  nshifts = shiftcount;
+	kernel_base[sym][kernel_size[sym]] = itemset[i] + 1;
+	kernel_size[sym]++;
+      }
 }
 
 
 
-/*-----------------------------------------------------------------.
-| Subroutine of get_state.  Create a new state for those items, if |
-| necessary.                                                       |
-`-----------------------------------------------------------------*/
-
-static core *
-new_state (int symbol)
-{
-  int n;
-  core *p;
-  short *isp1;
-  short *isp2;
-  short *iend;
-
-#if TRACE
-  fprintf (stderr, "Entering new_state, symbol = %d, state = %d\n",
-	   symbol, nstates);
-#endif
-
-  if (nstates >= MAXSHORT)
-    fatal (_("too many states (max %d)"), MAXSHORT);
-
-  isp1 = kernel_base[symbol];
-  iend = kernel_end[symbol];
-  n = iend - isp1;
-
-  p =
-    (core *) xcalloc ((unsigned) (sizeof (core) + (n - 1) * sizeof (short)), 1);
-  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;
-
-  nstates++;
-
-  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 we would get to (from the current state) by    |
+| shifting SYM.  Create a new state if no equivalent one exists |
+| already.  Used by append_states.                              |
 `--------------------------------------------------------------*/
 
-static int
-get_state (int symbol)
+static state *
+get_state (symbol_number sym, size_t core_size, item_number *core)
 {
-  int key;
-  short *isp1;
-  short *isp2;
-  short *iend;
-  core *sp;
-  int found;
-
-  int n;
-
-#if TRACE
-  fprintf (stderr, "Entering get_state, symbol = %d\n", symbol);
-#endif
+  state *s;
 
-  isp1 = kernel_base[symbol];
-  iend = kernel_end[symbol];
-  n = iend - isp1;
+  if (trace_flag & trace_automaton)
+    fprintf (stderr, "Entering get_state, symbol = %d (%s)\n",
+	     sym, symbols[sym]->tag);
 
-  /* add up the target state's active item numbers to get a hash key */
-  key = 0;
-  while (isp1 < iend)
-    key += *isp1++;
+  s = state_hash_lookup (core_size, core);
+  if (!s)
+    s = state_list_append (sym, core_size, core);
 
-  key = key % STATE_TABLE_SIZE;
+  if (trace_flag & trace_automaton)
+    fprintf (stderr, "Exiting get_state => %d\n", s->number);
 
-  sp = state_table[key];
-
-  if (sp)
-    {
-      found = 0;
-      while (!found)
-	{
-	  if (sp->nitems == n)
-	    {
-	      found = 1;
-	      isp1 = kernel_base[symbol];
-	      isp2 = sp->items;
-
-	      while (found && isp1 < iend)
-		{
-		  if (*isp1++ != *isp2++)
-		    found = 0;
-		}
-	    }
-
-	  if (!found)
-	    {
-	      if (sp->link)
-		{
-		  sp = sp->link;
-		}
-	      else		/* bucket exhausted and no match */
-		{
-		  sp = sp->link = new_state (symbol);
-		  found = 1;
-		}
-	    }
-	}
-    }
-  else				/* bucket is empty */
-    {
-      state_table[key] = sp = new_state (symbol);
-    }
-
-  return sp->number;
+  return s;
 }
 
-/*------------------------------------------------------------------.
-| 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.  |
-`------------------------------------------------------------------*/
+/*---------------------------------------------------------------.
+| Use the information computed by new_itemsets to find the state |
+| numbers reached by each shift transition from S.		 |
+|                                                                |
+| SHIFTSET is set up as a vector of those states.                |
+`---------------------------------------------------------------*/
 
 static void
-append_states (void)
+append_states (state *s)
 {
   int i;
-  int j;
-  int symbol;
 
-#if TRACE
-  fprintf (stderr, "Entering append_states\n");
-#endif
+  if (trace_flag & trace_automaton)
+    fprintf (stderr, "Entering append_states, state = %d\n", s->number);
 
-  /* first sort shift_symbol into increasing order */
+  /* First sort shift_symbol into increasing order.  */
 
   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;
+      symbol_number sym = shift_symbol[i];
+      int j;
+      for (j = i; 0 < j && sym < shift_symbol[j - 1]; j--)
+	shift_symbol[j] = shift_symbol[j - 1];
+      shift_symbol[j] = sym;
     }
 
   for (i = 0; i < nshifts; i++)
     {
-      symbol = shift_symbol[i];
-      shiftset[i] = get_state (symbol);
+      symbol_number sym = shift_symbol[i];
+      shiftset[i] = get_state (sym, kernel_size[sym], kernel_base[sym]);
     }
 }
 
 
-static void
-new_states (void)
-{
-  core *p;
-
-  p = (core *) xcalloc ((unsigned) (sizeof (core) - sizeof (short)), 1);
-  first_state = last_state = this_state = p;
-  nstates = 1;
-}
-
-
-static void
-save_shifts (void)
-{
-  shifts *p;
-  short *sp1;
-  short *sp2;
-  short *send;
-
-  p = (shifts *) xcalloc ((unsigned) (sizeof (shifts) +
-				      (nshifts - 1) * sizeof (short)), 1);
-
-  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;
-    }
-}
-
-
-/*------------------------------------------------------------------.
-| Subroutine of augment_automaton.  Create the next-to-final state, |
-| to which a shift has already been made in the initial state.      |
-`------------------------------------------------------------------*/
-
-static void
-insert_start_shift (void)
-{
-  core *statep;
-  shifts *sp;
-
-  statep = (core *) xcalloc ((unsigned) (sizeof (core) - sizeof (short)), 1);
-  statep->number = nstates;
-  statep->accessing_symbol = start_symbol;
-
-  last_state->next = statep;
-  last_state = statep;
-
-  /* Make a shift from this state to (what will be) the final state.  */
-  sp = XCALLOC (shifts, 1);
-  sp->number = nstates++;
-  sp->nshifts = 1;
-  sp->shifts[0] = nstates;
-
-  last_shift->next = sp;
-  last_shift = sp;
-}
-
-
-/*------------------------------------------------------------------.
-| 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.                                          |
-`------------------------------------------------------------------*/
+/*----------------------------------------------------------------.
+| 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.                                      |
+`----------------------------------------------------------------*/
 
 static void
-augment_automaton (void)
+save_reductions (state *s)
 {
-  int i;
-  int k;
-  core *statep;
-  shifts *sp;
-  shifts *sp2;
-  shifts *sp1 = NULL;
-
-  sp = first_shift;
+  int count = 0;
+  size_t i;
 
-  if (sp)
+  /* Find and count the active items that represent ends of rules. */
+  for (i = 0; i < nritemset; ++i)
     {
-      if (sp->number == 0)
+      item_number item = ritem[itemset[i]];
+      if (item_number_is_rule_number (item))
 	{
-	  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 *) xcalloc ((unsigned) (sizeof (shifts)
-							+
-							sp->nshifts *
-							sizeof (short)), 1);
-		  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;
-		  XFREE (sp);
-		}
-	      else
-		{
-		  sp2 = XCALLOC (shifts, 1);
-		  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
+	  rule_number r = item_number_as_rule_number (item);
+	  redset[count++] = &rules[r];
+	  if (r == 0)
 	    {
-	      /* 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 *) xcalloc (sizeof (shifts)
-					+ sp->nshifts * sizeof (short), 1);
-	      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;
-
-	      XFREE (sp);
-
-	      /* Create the next-to-final state, with shift to
-	         what will be the final state.  */
-	      insert_start_shift ();
+	      /* This is "reduce 0", i.e., accept. */
+	      assert (!final_state);
+	      final_state = s;
 	    }
 	}
-      else
-	{
-	  /* The initial state didn't even have any shifts.
-	     Give it one shift, to the next-to-final state.  */
-	  sp = XCALLOC (shifts, 1);
-	  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
-    {
-      /* There are no shifts for any state.
-         Make one shift, from the initial state to the next-to-final state.  */
-
-      sp = XCALLOC (shifts, 1);
-      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 ();
     }
 
-  /* 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 *) xcalloc ((unsigned) (sizeof (core) - sizeof (short)), 1);
-  statep->number = nstates;
-  last_state->next = statep;
-  last_state = statep;
-
-  /* Make the shift from the final state to the termination state.  */
-  sp = XCALLOC (shifts, 1);
-  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 *) xcalloc ((unsigned) (sizeof (core) - sizeof (short)), 1);
-  statep->number = nstates++;
-  last_state->next = statep;
-  last_state = statep;
+  /* Make a reductions structure and copy the data into it.  */
+  state_reductions_set (s, count, redset);
 }
 
-
-/*----------------------------------------------------------------.
-| 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.                                      |
-`----------------------------------------------------------------*/
+
+/*---------------.
+| Build STATES.  |
+`---------------*/
 
 static void
-save_reductions (void)
+set_states (void)
 {
-  short *isp;
-  short *rp1;
-  short *rp2;
-  int item;
-  int count;
-  reductions *p;
-
-  short *rend;
+  states = xcalloc (nstates, sizeof *states);
 
-  /* Find and count the active items that represent ends of rules. */
-
-  count = 0;
-  for (isp = itemset; isp < itemsetend; isp++)
+  while (first_state)
     {
-      item = ritem[*isp];
-      if (item < 0)
-	redset[count++] = -item;
-    }
-
-  /* Make a reductions structure and copy the data into it.  */
-
-  if (count)
-    {
-      p = (reductions *) xcalloc ((unsigned) (sizeof (reductions) +
-					      (count - 1) * sizeof (short)), 1);
-
-      p->number = this_state->number;
-      p->nreds = count;
-
-      rp1 = redset;
-      rp2 = p->rules;
-      rend = rp1 + count;
-
-      for (/* nothing */; rp1 < rend; ++rp1, ++rp2)
-	*rp2 = *rp1;
-
-      if (last_reduction)
-	{
-	  last_reduction->next = p;
-	  last_reduction = p;
-	}
-      else
-	{
-	  first_reduction = p;
-	  last_reduction = p;
-	}
+      state_list *this = first_state;
+
+      /* Pessimization, but simplification of the code: make sure all
+	 the states have valid transitions and reductions members,
+	 even if reduced to 0.  It is too soon for errs, which are
+	 computed later, but set_conflicts.  */
+      state *s = this->state;
+      if (!s->transitions)
+	state_transitions_set (s, 0, 0);
+      if (!s->reductions)
+	state_reductions_set (s, 0, 0);
+
+      states[s->number] = s;
+
+      first_state = this->next;
+      free (this);
     }
+  first_state = NULL;
+  last_state = NULL;
 }
 
-
+
 /*-------------------------------------------------------------------.
 | Compute the nondeterministic finite state machine (see state.h for |
 | details) from the grammar.                                         |
@@ -665,37 +334,44 @@ save_reductions (void)
 void
 generate_states (void)
 {
+  item_number initial_core = 0;
+  state_list *list = NULL;
   allocate_storage ();
-  new_closure (nitems);
-  new_states ();
+  new_closure (nritems);
+
+  /* Create the initial state.  The 0 at the lhs is the index of the
+     item of this initial rule.  */
+  state_list_append (0, 1, &initial_core);
 
-  while (this_state)
+  /* States are queued when they are created; process them all.  */
+  for (list = first_state; list; list = list->next)
     {
+      state *s = list->state;
+      if (trace_flag & trace_automaton)
+	fprintf (stderr, "Processing state %d (reached by %s)\n",
+		 s->number,
+		 symbols[s->accessing_symbol]->tag);
       /* 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;
+      closure (s->items, s->nitems);
+      /* Record the reductions allowed out of this state.  */
+      save_reductions (s);
+      /* Find the itemsets of the states that shifts can reach.  */
+      new_itemsets (s);
+      /* Find or create the core structures for those states.  */
+      append_states (s);
+
+      /* Create the shifts structures for the shifts to those states,
+	 now that the state numbers transitioning to are known.  */
+      state_transitions_set (s, nshifts, shiftset);
     }
 
   /* discard various storage */
   free_closure ();
   free_storage ();
 
-  /* set up initial and final states as parser wants them */
-  augment_automaton ();
+  /* Set up STATES. */
+  set_states ();
 }