* src/closure.c (closure): Use nrules instead of playing tricks

[bison.git] / src / closure.c

diff --git a/src/closure.c b/src/closure.c
index ad349196148eafe82f1df5e2172cfd28d3cd5fc4..12bb5817f36f340af9696e23dd06891c106a31d6 100644 (file)
--- a/src/closure.c
+++ b/src/closure.c
@@ -1,352 +1,255 @@
 /* Subroutines for bison
 /* Subroutines for bison

-   Copyright (C) 1984, 1989 Free Software Foundation, Inc.
+   Copyright 1984, 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.

 
 

-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.  */

 
 

-
-/* subroutines of file LR0.c.
-
-Entry points:
-
-  closure (items, n)
-
-Given a vector of item numbers items, of length n,
-set up ruleset and itemset to indicate what rules could be run
-and which items could be accepted when those items are the active ones.
-
-ruleset contains a bit for each rule.  closure sets the bits
-for all rules which could potentially describe the next input to be read.
-
-itemset is a vector of item numbers; itemsetend points to just beyond the end
- of the part of it that is significant.
-closure places there the indices of all items which represent units of
-input that could arrive next.
-
-  initialize_closure (n)
-
-Allocates the itemset and ruleset vectors,
-and precomputes useful data so that closure can be called.
-n is the number of elements to allocate for itemset.
-
-  finalize_closure ()
-
-Frees itemset, ruleset and internal data.
-
-*/
-
-#include <stdio.h>

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

-#include "machine.h"
-#include "alloc.h"
+#include "getargs.h"

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

+#include "reader.h"
+#include "closure.h"
+#include "derives.h"
+#include "warshall.h"

 
 

-
-extern short **derives;
-extern char **tags;
-
-void initialize_closure PARAMS((int));
-void set_fderives PARAMS((void));
-void set_firsts PARAMS((void));
-void closure PARAMS((short *, int));
-void finalize_closure PARAMS((void));
-
-extern void RTC PARAMS((unsigned *, int));
-
+/* NITEMSET is the size of the array ITEMSET.  */

 short *itemset;
 short *itemset;

-short *itemsetend;
+int nitemset;
+

 static unsigned *ruleset;
 
 /* internal data.  See comments before set_fderives and set_firsts.  */
 static unsigned *fderives;
 static unsigned *firsts;
 
 static unsigned *ruleset;
 
 /* internal data.  See comments before set_fderives and set_firsts.  */
 static unsigned *fderives;
 static unsigned *firsts;
 

+/* Retrieve the FDERIVES/FIRSTS sets of the nonterminals numbered Var.  */
+#define FDERIVES(Var)   (fderives + ((Var) - ntokens) * rulesetsize)
+#define   FIRSTS(Var)   (firsts   + ((Var) - ntokens) * varsetsize)
+

 /* number of words required to hold a bit for each rule */
 static int rulesetsize;
 
 /* number of words required to hold a bit for each variable */
 static int varsetsize;
 /* number of words required to hold a bit for each rule */
 static int rulesetsize;
 
 /* number of words required to hold a bit for each variable */
 static int varsetsize;

+\f

 
 

+/*-----------------.
+| Debugging code.  |
+`-----------------*/

 
 

-void
-initialize_closure (int n)
+static void
+print_closure (const char *title, short *array, size_t size)

 {
 {

-  itemset = NEW2(n, short);
-
-  rulesetsize = WORDSIZE(nrules + 1);
-  ruleset = NEW2(rulesetsize, unsigned);
-
-  set_fderives();
+  size_t i;
+  fprintf (stderr, "Closure: %s\n", title);
+  for (i = 0; i < size; ++i)
+    {
+      short *rp;
+      fprintf (stderr, "  %2d: .", array[i]);
+      for (rp = &ritem[array[i]]; *rp > 0; ++rp)
+       fprintf (stderr, " %s", tags[*rp]);
+      fprintf (stderr, "  (rule %d)\n", -*rp);
+    }
+  fputs ("\n\n", stderr);

 }
 
 
 }
 
 

-
-/* set fderives to an nvars by nrules matrix of bits
-   indicating which rules can help derive the beginning of the data
-   for each nonterminal.  For example, if symbol 5 can be derived as
-   the sequence of symbols 8 3 20, and one of the rules for deriving
-   symbol 8 is rule 4, then the [5 - ntokens, 4] bit in fderives is set.  */
-void
-set_fderives (void)
+static void
+print_firsts (void)

 {
 {

-  register unsigned *rrow;
-  register unsigned *vrow;
-  register int j;
-  register unsigned cword;
-  register short *rp;
-  register int b;
-
-  int ruleno;
-  int i;
-
-  fderives = NEW2(nvars * rulesetsize, unsigned) - ntokens * rulesetsize;
-
-  set_firsts();
-
-  rrow = fderives + ntokens * rulesetsize;
+  int i, j;

 
 

+  fprintf (stderr, "FIRSTS\n");

   for (i = ntokens; i < nsyms; i++)
     {
   for (i = ntokens; i < nsyms; i++)
     {

-      vrow = firsts + ((i - ntokens) * varsetsize);
-      cword = *vrow++;
-      b = 0;
-      for (j = ntokens; j < nsyms; j++)
-       {
-         if (cword & (1 << b))
-           {
-             rp = derives[j];
-             while ((ruleno = *rp++) > 0)
-               {
-                 SETBIT(rrow, ruleno);
-               }
-           }
-
-         b++;
-         if (b >= BITS_PER_WORD && j + 1 < nsyms)
-           {
-             cword = *vrow++;
-             b = 0;
-           }
-       }
-
-      rrow += rulesetsize;
+      fprintf (stderr, "\t%s firsts\n", tags[i]);
+      for (j = 0; j < nvars; j++)
+       if (BITISSET (FIRSTS (i), j))
+         fprintf (stderr, "\t\t%d (%s)\n", j + ntokens, tags[j + ntokens]);

     }
     }

-
-#ifdef DEBUG
-  print_fderives();
-#endif
-
-  FREE(firsts);
+  fprintf (stderr, "\n\n");

 }
 
 
 }
 
 

-
-/* set firsts to be an nvars by nvars bit matrix indicating which items
-   can represent the beginning of the input corresponding to which other items.
-   For example, if some rule expands symbol 5 into the sequence of symbols 8 3 20,
-   the symbol 8 can be the beginning of the data for symbol 5,
-   so the bit [8 - ntokens, 5 - ntokens] in firsts is set. */
-void
-set_firsts (void)
+static void
+print_fderives (void)

 {
 {

-  register unsigned *row;
-/*   register int done; JF unused */
-  register int symbol;
-  register short *sp;
-  register int rowsize;
-

   int i;
   int i;

+  int j;

 
 

-  varsetsize = rowsize = WORDSIZE(nvars);
+  fprintf (stderr, "FDERIVES\n");

 
 

-  firsts = NEW2(nvars * rowsize, unsigned);
-
-  row = firsts;

   for (i = ntokens; i < nsyms; i++)
     {
   for (i = ntokens; i < nsyms; i++)
     {

-      sp = derives[i];
-      while (*sp >= 0)
-       {
-         symbol = ritem[rrhs[*sp++]];
-         if (ISVAR(symbol))
-           {
-             symbol -= ntokens;
-             SETBIT(row, symbol);
-           }
-       }
-
-      row += rowsize;
+      fprintf (stderr, "\t%s derives\n", tags[i]);
+      for (j = 0; j <= nrules; j++)
+       if (BITISSET (FDERIVES (i), j))
+         {
+           short *rhsp;
+           fprintf (stderr, "\t\t%d:", j);
+           for (rhsp = ritem + rule_table[j].rhs; *rhsp > 0; ++rhsp)
+             fprintf (stderr, " %s", tags[*rhsp]);
+           fputc ('\n', stderr);
+         }

     }
     }

-
-  RTC(firsts, nvars);
-
-#ifdef DEBUG
-  print_firsts();
-#endif
+  fprintf (stderr, "\n\n");

 }
 }

-
-
-void
-closure (short *core, int n)
+\f
+/*-------------------------------------------------------------------.
+| Set FIRSTS to be an NVARS by NVARS bit matrix indicating which     |
+| items can represent the beginning of the input corresponding to    |
+| which other items.                                                 |
+|                                                                    |
+| For example, if some rule expands symbol 5 into the sequence of    |
+| symbols 8 3 20, the symbol 8 can be the beginning of the data for  |
+| symbol 5, so the bit [8 - ntokens, 5 - ntokens] in firsts is set.  |
+`-------------------------------------------------------------------*/
+
+static void
+set_firsts (void)

 {
 {

-  register int ruleno;
-  register unsigned word;
-  register short *csp;
-  register unsigned *dsp;
-  register unsigned *rsp;
-
-  short *csend;
-  unsigned *rsend;
-  int symbol;
-  int itemno;
+  int i, j;

 
 

-  rsp = ruleset;
-  rsend = ruleset + rulesetsize;
-  csend = core + n;
+  varsetsize = WORDSIZE (nvars);

 
 

-  if (n == 0)
-    {
-      dsp = fderives + start_symbol * rulesetsize;
-      while (rsp < rsend)
-       *rsp++ = *dsp++;
-    }
-  else
-    {
-      while (rsp < rsend)
-       *rsp++ = 0;
-
-      csp = core;
-      while (csp < csend)
-       {
-         symbol = ritem[*csp++];
-         if (ISVAR(symbol))
-           {
-             dsp = fderives + symbol * rulesetsize;
-             rsp = ruleset;
-             while (rsp < rsend)
-               *rsp++ |= *dsp++;
-           }
-       }
-    }
+  firsts = XCALLOC (unsigned, nvars * varsetsize);

 
 

-  ruleno = 0;
-  itemsetend = itemset;
-  csp = core;
-  rsp = ruleset;
-  while (rsp < rsend)
-    {
-      word = *rsp++;
-      if (word == 0)
-       {
-         ruleno += BITS_PER_WORD;
-       }
-      else
-       {
-         register int b;
-
-         for (b = 0; b < BITS_PER_WORD; b++)
-           {
-             if (word & (1 << b))
-               {
-                 itemno = rrhs[ruleno];
-                 while (csp < csend && *csp < itemno)
-                   *itemsetend++ = *csp++;
-                 *itemsetend++ = itemno;
-               }
-
-             ruleno++;
-           }
-       }
-    }
+  for (i = ntokens; i < nsyms; i++)
+    for (j = 0; derives[i][j] >= 0; ++j)
+      {
+       int symbol = ritem[rule_table[derives[i][j]].rhs];
+       if (ISVAR (symbol))
+         SETBIT (FIRSTS (i), symbol - ntokens);
+      }

 
 

-  while (csp < csend)
-    *itemsetend++ = *csp++;
+  RTC (firsts, nvars);

 
 

-#ifdef DEBUG
-  print_closure(n);
-#endif
+  if (trace_flag)
+    print_firsts ();

 }
 
 }
 

-
-void
-finalize_closure (void)
+/*-------------------------------------------------------------------.
+| Set FDERIVES to an NVARS by NRULES matrix of bits indicating which |
+| rules can help derive the beginning of the data for each           |
+| nonterminal.                                                       |
+|                                                                    |
+| For example, if symbol 5 can be derived as the sequence of symbols |
+| 8 3 20, and one of the rules for deriving symbol 8 is rule 4, then |
+| the [5 - NTOKENS, 4] bit in FDERIVES is set.                       |
+`-------------------------------------------------------------------*/
+
+static void
+set_fderives (void)

 {
 {

-  FREE(itemset);
-  FREE(ruleset);
-  FREE(fderives + ntokens * rulesetsize);
-}
+  int i, j, k;

 
 

+  fderives = XCALLOC (unsigned, nvars * rulesetsize);

 
 

+  set_firsts ();

 
 

-#ifdef DEBUG
+  for (i = ntokens; i < nsyms; ++i)
+    for (j = ntokens; j < nsyms; ++j)
+      if (BITISSET (FIRSTS (i), j - ntokens))
+       for (k = 0; derives[j][k] > 0; ++k)
+         SETBIT (FDERIVES (i), derives[j][k]);

 
 

-print_closure(n)
-int n;
-{
-  register short *isp;
+  if (trace_flag)
+    print_fderives ();

 
 

-  printf("\n\nn = %d\n\n", n);
-  for (isp = itemset; isp < itemsetend; isp++)
-    printf("   %d\n", *isp);
+  XFREE (firsts);

 }
 }

-
+\f

 
 void
 
 void

-print_firsts (void)
+new_closure (int n)

 {
 {

-  register int i;
-  register int j;
-  register unsigned *rowp;
-
-  printf(_("\n\n\nFIRSTS\n\n"));
-
-  for (i = ntokens; i < nsyms; i++)
-    {
-      printf(_("\n\n%s firsts\n\n"), tags[i]);
+  itemset = XCALLOC (short, n);

 
 

-      rowp = firsts + ((i - ntokens) * varsetsize);
+  rulesetsize = WORDSIZE (nrules + 1);
+  ruleset = XCALLOC (unsigned, rulesetsize);

 
 

-      for (j = 0; j < nvars; j++)
-       if (BITISSET (rowp, j))
-         printf("   %s\n", tags[j + ntokens]);
-    }
+  set_fderives ();

 }
 
 
 }
 
 

+

 void
 void

-print_fderives (void)
+closure (short *core, int n)

 {
 {

-  register int i;
-  register int j;
-  register unsigned *rp;
+  /* Index over CORE. */
+  int c;

 
 

-  printf(_("\n\n\nFDERIVES\n"));
+  /* Index over RULESET. */
+  int r;

 
 

-  for (i = ntokens; i < nsyms; i++)
+  /* A bit index over RULESET. */
+  int ruleno;
+
+  if (trace_flag)
+    print_closure ("input", core, n);
+
+  if (n == 0)

     {
     {

-      printf(_("\n\n%s derives\n\n"), tags[i]);
-      rp = fderives + i * rulesetsize;
+      for (r = 0; r < rulesetsize; ++r)
+       ruleset[r] = FDERIVES (start_symbol)[r];
+    }
+  else
+    {
+      for (r = 0; r < rulesetsize; ++r)
+       ruleset[r] = 0;

 
 

-      for (j = 0; j <= nrules; j++)
-       if (BITISSET (rp, j))
-         printf("   %d\n", j);
+      for (c = 0; c < n; ++c)
+       if (ISVAR (ritem[core[c]]))
+         for (r = 0; r < rulesetsize; ++r)
+           ruleset[r] |= FDERIVES (ritem[core[c]])[r];

     }
 
     }
 

-  fflush(stdout);
+  nitemset = 0;
+  c = 0;
+  for (ruleno = 0; ruleno < nrules + 1; ++ruleno)
+    if (BITISSET (ruleset, ruleno))
+      {
+       int itemno = rule_table[ruleno].rhs;
+       while (c < n && core[c] < itemno)
+         {
+           itemset[nitemset] = core[c];
+           nitemset++;
+           c++;
+         }
+       itemset[nitemset] = itemno;
+       nitemset++;
+      }
+
+  while (c < n)
+    {
+      itemset[nitemset] = core[c];
+      nitemset++;
+      c++;
+    }
+
+  if (trace_flag)
+    print_closure ("output", itemset, nitemset);

 }
 
 }
 

-#endif
+
+void
+free_closure (void)
+{
+  XFREE (itemset);
+  XFREE (ruleset);
+  XFREE (fderives);
+}