X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/720e5c1bc36411c1a0591a525a897f47cfd17987..643a5994714b21dfde1a44a52ccffd0a300e5131:/src/closure.c

diff --git a/src/closure.c b/src/closure.c
index ab086342..9e595c81 100644
--- a/src/closure.c
+++ b/src/closure.c
@@ -1,5 +1,5 @@
 /* Subroutines for bison
-   Copyright 1984, 1989, 2000, 2001 Free Software Foundation, Inc.
+   Copyright (C) 1984, 1989, 2000, 2001, 2002 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -19,31 +19,28 @@
    02111-1307, USA.  */
 
 #include "system.h"
+#include "bitset.h"
+#include "bitsetv.h"
 #include "getargs.h"
+#include "symtab.h"
 #include "gram.h"
 #include "reader.h"
 #include "closure.h"
 #include "derives.h"
-#include "warshall.h"
 
-/* ITEMSETSIZE is the size of the array ITEMSET.  */
+/* NITEMSET is the size of the array ITEMSET.  */
 short *itemset;
-size_t itemsetsize;
+int nitemset;
 
-static unsigned *ruleset;
+static bitset ruleset;
 
 /* internal data.  See comments before set_fderives and set_firsts.  */
-static unsigned *fderives;
-static unsigned *firsts;
+static bitsetv fderives = NULL;
+static bitsetv firsts = NULL;
 
-#define FDERIVES(Symbol)   (fderives + (Symbol) * rulesetsize)
-#define   FIRSTS(Symbol)   (firsts   + (Symbol) * 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;
+/* Retrieve the FDERIVES/FIRSTS sets of the nonterminals numbered Var.  */
+#define FDERIVES(Var)   fderives[(Var) - ntokens]
+#define   FIRSTS(Var)   firsts[(Var) - ntokens]
 
 
 /*-----------------.
@@ -51,34 +48,35 @@ static int varsetsize;
 `-----------------*/
 
 static void
-print_closure (int n)
+print_closure (const char *title, short *array, size_t size)
 {
-  int i;
-  fprintf (stderr, "n = %d\n", n);
-  for (i = 0; i < itemsetsize; ++i)
-    fprintf (stderr, "   %d\n", itemset[i]);
-  fprintf (stderr, "\n\n");
+  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", symbols[*rp]->tag);
+      fprintf (stderr, "  (rule %d)\n", -*rp - 1);
+    }
+  fputs ("\n\n", stderr);
 }
 
 
 static void
 print_firsts (void)
 {
-  int i;
-  int j;
-  unsigned *rowp;
+  int i, j;
 
   fprintf (stderr, "FIRSTS\n");
-
   for (i = ntokens; i < nsyms; i++)
     {
-      fprintf (stderr, "\t%s firsts\n", tags[i]);
-
-      rowp = FIRSTS (i - ntokens);
-
+      fprintf (stderr, "\t%s firsts\n", symbols[i]->tag);
       for (j = 0; j < nvars; j++)
-	if (BITISSET (rowp, j))
-	  fprintf (stderr, "\t\t%d (%s)\n", j + ntokens, tags[j + ntokens]);
+	if (bitset_test (FIRSTS (i), j))
+	  fprintf (stderr, "\t\t%d (%s)\n",
+		   j + ntokens, symbols[j + ntokens]->tag);
     }
   fprintf (stderr, "\n\n");
 }
@@ -87,72 +85,104 @@ print_firsts (void)
 static void
 print_fderives (void)
 {
-  int i;
-  int j;
-  unsigned *rp;
+  int i, j;
 
   fprintf (stderr, "FDERIVES\n");
-
   for (i = ntokens; i < nsyms; i++)
     {
-      fprintf (stderr, "\t%s derives\n", tags[i]);
-      rp = FDERIVES (i);
-
-      for (j = 0; j <= nrules; j++)
-	if (BITISSET (rp, j))
+      fprintf (stderr, "\t%s derives\n", symbols[i]->tag);
+      for (j = 0; j < nrules + 1; j++)
+	if (bitset_test (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]);
+	    fprintf (stderr, "\t\t%d:", j - 1);
+	    for (rhsp = rules[j].rhs; *rhsp >= 0; ++rhsp)
+	      fprintf (stderr, " %s", symbols[*rhsp]->tag);
 	    fputc ('\n', stderr);
 	  }
     }
   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.  |
-`-------------------------------------------------------------------*/
+
+/*--------------------------------------------------------.
+| Display the MATRIX array of SIZE bitsets of size SIZE.  |
+`--------------------------------------------------------*/
 
 static void
-set_firsts (void)
+bitmatrix_print (const char *title, bitsetv matrix)
 {
-  unsigned *row;
-  int symbol;
-  short *sp;
-  int rowsize;
+  size_t i, j;
+  size_t size = bitset_size (matrix[0]);
+
+  /* Title. */
+  fprintf (stderr, "%s BEGIN\n", title);
+
+  /* Column numbers. */
+  fputs ("   ", stderr);
+  for (i = 0; i < size; ++i)
+    putc (i / 10 ? '0' + i / 10 : ' ', stderr);
+  putc ('\n', stderr);
+  fputs ("   ", stderr);
+  for (i = 0; i < size; ++i)
+    fprintf (stderr, "%d", i % 10);
+  putc ('\n', stderr);
+
+  /* Bar. */
+  fputs ("  .", stderr);
+  for (i = 0; i < size; ++i)
+    putc ('-', stderr);
+  fputs (".\n", stderr);
+
+  /* Contents. */
+  for (i = 0; i < size; ++i)
+    {
+      fprintf (stderr, "%2d|", i);
+      for (j = 0; j < size; ++j)
+	fputs (bitset_test (matrix[i], j) ? "1" : " ", stderr);
+      fputs ("|\n", stderr);
+    }
 
-  int i;
+  /* Bar. */
+  fputs ("  `", stderr);
+  for (i = 0; i < size; ++i)
+    putc ('-', stderr);
+  fputs ("'\n", stderr);
 
-  varsetsize = rowsize = WORDSIZE (nvars);
+  /* End title. */
+  fprintf (stderr, "%s END\n\n", title);
+}
+
+/*------------------------------------------------------------------.
+| Set FIRSTS to be an NVARS array of NVARS bitsets 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] in first[5 - ntokens] (= FIRST |
+| (5)) is set.                                                      |
+`------------------------------------------------------------------*/
+
+static void
+set_firsts (void)
+{
+  int i, j;
 
-  firsts = XCALLOC (unsigned, nvars * rowsize);
+  firsts = bitsetv_create (nvars, nvars, BITSET_FIXED);
 
-  row = firsts;
   for (i = ntokens; i < nsyms; i++)
-    {
-      sp = derives[i];
-      while (*sp >= 0)
-	{
-	  symbol = ritem[rule_table[*sp++].rhs];
-	  if (ISVAR (symbol))
-	    {
-	      symbol -= ntokens;
-	      SETBIT (row, symbol);
-	    }
-	}
-
-      row += rowsize;
-    }
+    for (j = 0; derives[i][j] >= 0; ++j)
+      {
+	int symbol = rules[derives[i][j]].rhs[0];
+	if (ISVAR (symbol))
+	  bitset_set (FIRSTS (i), symbol - ntokens);
+      }
 
-  RTC (firsts, nvars);
+  if (trace_flag)
+    bitmatrix_print ("RTC: Input", firsts);
+  bitsetv_reflexive_transitive_closure (firsts);
+  if (trace_flag)
+    bitmatrix_print ("RTC: Output", firsts);
 
   if (trace_flag)
     print_firsts ();
@@ -171,51 +201,22 @@ set_firsts (void)
 static void
 set_fderives (void)
 {
-  unsigned *rrow;
-  unsigned *vrow;
-  int j;
-  unsigned cword;
-  short *rp;
-  int b;
-
-  int ruleno;
-  int i;
+  int i, j, k;
 
-  fderives = XCALLOC (unsigned, nvars * rulesetsize) - ntokens * rulesetsize;
+  fderives = bitsetv_create (nvars, nrules + 1, BITSET_FIXED);
 
   set_firsts ();
 
-  rrow = FDERIVES (ntokens);
-
-  for (i = ntokens; i < nsyms; i++)
-    {
-      vrow = FIRSTS (i - ntokens);
-      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;
-    }
+  for (i = ntokens; i < nsyms; ++i)
+    for (j = ntokens; j < nsyms; ++j)
+      if (bitset_test (FIRSTS (i), j - ntokens))
+	for (k = 0; derives[j][k] > 0; ++k)
+	  bitset_set (FDERIVES (i), derives[j][k]);
 
   if (trace_flag)
     print_fderives ();
 
-  XFREE (firsts);
+  bitsetv_free (firsts);
 }
 
 
@@ -224,8 +225,7 @@ new_closure (int n)
 {
   itemset = XCALLOC (short, n);
 
-  rulesetsize = WORDSIZE (nrules + 1);
-  ruleset = XCALLOC (unsigned, rulesetsize);
+  ruleset = bitset_create (nrules + 1, BITSET_FIXED);
 
   set_fderives ();
 }
@@ -235,76 +235,46 @@ new_closure (int n)
 void
 closure (short *core, int n)
 {
-  int ruleno;
-  short *csp;
+  /* Index over CORE. */
+  int c;
 
-  int itemno;
-  int i;
+  /* A bit index over RULESET. */
+  int ruleno;
 
   if (trace_flag)
-    {
-      fprintf (stderr, "Entering closure (items = {");
-      for (i = 0; i < n; ++i)
-	fprintf (stderr, " %d ", core[i]);
-      fprintf (stderr, "}, nitems = %d)\n", n);
-    }
+    print_closure ("input", core, n);
 
-  if (n == 0)
-    {
-      for (i = 0; i < rulesetsize; ++i)
-	ruleset[i] = FDERIVES (start_symbol)[i];
-    }
-  else
-    {
-      for (i = 0; i < rulesetsize; ++i)
-	ruleset[i] = 0;
-
-      for (i = 0; i < n; ++i)
-	{
-	  int symbol = ritem[core[i]];
-	  if (ISVAR (symbol))
-	    {
-	      int j;
-	      for (j = 0; j < rulesetsize; ++j)
-		ruleset[j] |= FDERIVES (symbol)[j];
-	    }
-	}
-    }
+  bitset_zero (ruleset);
 
-  ruleno = 0;
-  itemsetsize = 0;
-  csp = core;
-  for (i = 0; i < rulesetsize; ++i)
+  for (c = 0; c < n; ++c)
+    if (ISVAR (ritem[core[c]]))
+      bitset_or (ruleset, ruleset, FDERIVES (ritem[core[c]]));
+
+  nitemset = 0;
+  c = 0;
+  for (ruleno = 0; ruleno < nrules + 1; ++ruleno)
+    if (bitset_test (ruleset, ruleno))
+      {
+	int itemno = rules[ruleno].rhs - ritem;
+	while (c < n && core[c] < itemno)
+	  {
+	    itemset[nitemset] = core[c];
+	    nitemset++;
+	    c++;
+	  }
+	itemset[nitemset] = itemno;
+	nitemset++;
+      }
+
+  while (c < n)
     {
-      int word = ruleset[i];
-      if (word == 0)
-	{
-	  ruleno += BITS_PER_WORD;
-	}
-      else
-	{
-	  int b;
-
-	  for (b = 0; b < BITS_PER_WORD; b++)
-	    {
-	      if (word & (1 << b))
-		{
-		  itemno = rule_table[ruleno].rhs;
-		  while (csp < (core + n) && *csp < itemno)
-		    itemset[itemsetsize++] = *csp++;
-		  itemset[itemsetsize++] = itemno;
-		}
-
-	      ruleno++;
-	    }
-	}
+      itemset[nitemset] = core[c];
+      nitemset++;
+      c++;
     }
 
-  while (csp < (core + n))
-    itemset[itemsetsize++] = *csp++;
-
   if (trace_flag)
-    print_closure (n);
+    print_closure ("output", itemset, nitemset);
 }
 
 
@@ -312,6 +282,6 @@ void
 free_closure (void)
 {
   XFREE (itemset);
-  XFREE (ruleset);
-  XFREE (fderives + ntokens * rulesetsize);
+  bitset_free (ruleset);
+  bitsetv_free (fderives);
 }