/* 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, 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. */
+#include "system.h"
+#include "getargs.h"
+#include "gram.h"
+#include "reader.h"
+#include "closure.h"
+#include "derives.h"
+#include "warshall.h"
-/* subroutines of file LR0.c.
-
-Entry points:
-
- closure (items, n)
+/* ITEMSETSIZE is the size of the array ITEMSET. */
+short *itemset;
+int itemsetsize;
-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.
+static unsigned *ruleset;
-ruleset contains a bit for each rule. closure sets the bits
-for all rules which could potentially describe the next input to be read.
+/* internal data. See comments before set_fderives and set_firsts. */
+static unsigned *fderives;
+static unsigned *firsts;
-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.
+#define FDERIVES(Symbol) (fderives + (Symbol) * rulesetsize)
+#define FIRSTS(Symbol) (firsts + (Symbol) * varsetsize)
- initialize_closure (n)
+/* number of words required to hold a bit for each rule */
+static int rulesetsize;
-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.
+/* number of words required to hold a bit for each variable */
+static int varsetsize;
+\f
- finalize_closure ()
+/*-----------------.
+| Debugging code. |
+`-----------------*/
-Frees itemset, ruleset and internal data.
+static void
+print_closure (int n)
+{
+ int i;
+ fprintf (stderr, "n = %d\n", n);
+ for (i = 0; i < itemsetsize; ++i)
+ fprintf (stderr, " %d\n", itemset[i]);
+ fprintf (stderr, "\n\n");
+}
-*/
-#include <stdio.h>
-#include "system.h"
-#include "machine.h"
-#include "alloc.h"
-#include "gram.h"
+static void
+print_firsts (void)
+{
+ int i;
+ int j;
+ unsigned *rowp;
+ fprintf (stderr, "FIRSTS\n");
-extern short **derives;
-extern char **tags;
+ for (i = ntokens; i < nsyms; i++)
+ {
+ fprintf (stderr, "\t%s firsts\n", tags[i]);
-void set_fderives();
-void set_firsts();
+ rowp = FIRSTS (i - ntokens);
-extern void RTC();
+ for (j = 0; j < nvars; j++)
+ if (BITISSET (rowp, j))
+ fprintf (stderr, "\t\t%d (%s)\n", j + ntokens, tags[j + ntokens]);
+ }
+ fprintf (stderr, "\n\n");
+}
-short *itemset;
-short *itemsetend;
-static unsigned *ruleset;
-/* internal data. See comments before set_fderives and set_firsts. */
-static unsigned *fderives;
-static unsigned *firsts;
-
-/* number of words required to hold a bit for each rule */
-static int rulesetsize;
+static void
+print_fderives (void)
+{
+ int i;
+ int j;
+ unsigned *rp;
-/* number of words required to hold a bit for each variable */
-static int varsetsize;
+ fprintf (stderr, "FDERIVES\n");
+ for (i = ntokens; i < nsyms; i++)
+ {
+ fprintf (stderr, "\t%s derives\n", tags[i]);
+ rp = FDERIVES (i);
-void
-initialize_closure(n)
-int n;
+ for (j = 0; j <= nrules; j++)
+ if (BITISSET (rp, 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);
+ }
+ }
+ fprintf (stderr, "\n\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)
{
- itemset = NEW2(n, short);
+ int rowsize;
- rulesetsize = WORDSIZE(nrules + 1);
- ruleset = NEW2(rulesetsize, unsigned);
+ int i, j;
- set_fderives();
-}
+ varsetsize = rowsize = WORDSIZE (nvars);
+ firsts = XCALLOC (unsigned, nvars * rowsize);
+ 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))
+ {
+ symbol -= ntokens;
+ SETBIT (FIRSTS (i - ntokens), symbol);
+ }
+ }
+
+ RTC (firsts, nvars);
+
+ if (trace_flag)
+ print_firsts ();
+}
-/* 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()
+/*-------------------------------------------------------------------.
+| 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)
{
- register unsigned *rrow;
- register unsigned *vrow;
- register int j;
- register unsigned cword;
- register short *rp;
- register int b;
+ unsigned *rrow;
+ unsigned *vrow;
+ int j;
+ unsigned cword;
+ short *rp;
+ int b;
int ruleno;
int i;
- fderives = NEW2(nvars * rulesetsize, unsigned) - ntokens * rulesetsize;
+ fderives = XCALLOC (unsigned, nvars * rulesetsize) - ntokens * rulesetsize;
- set_firsts();
+ set_firsts ();
- rrow = fderives + ntokens * rulesetsize;
+ rrow = FDERIVES (ntokens);
for (i = ntokens; i < nsyms; i++)
{
- vrow = firsts + ((i - ntokens) * varsetsize);
+ vrow = FIRSTS (i - ntokens);
cword = *vrow++;
b = 0;
for (j = ntokens; j < nsyms; j++)
{
rp = derives[j];
while ((ruleno = *rp++) > 0)
- {
- SETBIT(rrow, ruleno);
- }
+ SETBIT (rrow, ruleno);
}
b++;
rrow += rulesetsize;
}
-#ifdef DEBUG
- print_fderives();
-#endif
+ if (trace_flag)
+ print_fderives ();
- FREE(firsts);
+ XFREE (firsts);
}
+\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. */
void
-set_firsts()
+new_closure (int n)
{
- register unsigned *row;
-/* register int done; JF unused */
- register int symbol;
- register short *sp;
- register int rowsize;
-
- int i;
-
- varsetsize = rowsize = WORDSIZE(nvars);
+ itemset = XCALLOC (short, n);
- firsts = NEW2(nvars * rowsize, unsigned);
+ rulesetsize = WORDSIZE (nrules + 1);
+ ruleset = XCALLOC (unsigned, rulesetsize);
- row = firsts;
- 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;
- }
-
- RTC(firsts, nvars);
-
-#ifdef DEBUG
- print_firsts();
-#endif
+ set_fderives ();
}
+
void
-closure(core, n)
-short *core;
-int n;
+closure (short *core, int n)
{
- register int ruleno;
- register unsigned word;
- register short *csp;
- register unsigned *dsp;
- register unsigned *rsp;
+ /* Index over CORE. */
+ int c;
- short *csend;
- unsigned *rsend;
- int symbol;
- int itemno;
+ /* Index over RULESET. */
+ int r;
- rsp = ruleset;
- rsend = ruleset + rulesetsize;
- csend = core + n;
+ /* A bit index over RULESET. */
+ int ruleno;
+
+ if (trace_flag)
+ {
+ fprintf (stderr, "Entering closure (items = {");
+ for (c = 0; c < n; ++c)
+ fprintf (stderr, " %d ", core[c]);
+ fprintf (stderr, "})\n");
+ }
if (n == 0)
{
- dsp = fderives + start_symbol * rulesetsize;
- while (rsp < rsend)
- *rsp++ = *dsp++;
+ for (r = 0; r < rulesetsize; ++r)
+ ruleset[r] = FDERIVES (start_symbol)[r];
}
else
{
- while (rsp < rsend)
- *rsp++ = 0;
+ for (r = 0; r < rulesetsize; ++r)
+ ruleset[r] = 0;
- csp = core;
- while (csp < csend)
- {
- symbol = ritem[*csp++];
- if (ISVAR(symbol))
- {
- dsp = fderives + symbol * rulesetsize;
- rsp = ruleset;
- while (rsp < rsend)
- *rsp++ |= *dsp++;
- }
- }
+ for (c = 0; c < n; ++c)
+ if (ISVAR (ritem[core[c]]))
+ for (r = 0; r < rulesetsize; ++r)
+ ruleset[r] |= FDERIVES (ritem[core[c]])[r];
}
- ruleno = 0;
- itemsetend = itemset;
- csp = core;
- rsp = ruleset;
- while (rsp < rsend)
+ itemsetsize = 0;
+ c = 0;
+ for (ruleno = 0; ruleno < rulesetsize * BITS_PER_WORD; ++ruleno)
+ if (BITISSET (ruleset, ruleno))
+ {
+ int itemno = rule_table[ruleno].rhs;
+ while (c < n && core[c] < itemno)
+ {
+ itemset[itemsetsize] = core[c];
+ itemsetsize++;
+ c++;
+ }
+ itemset[itemsetsize] = itemno;
+ itemsetsize++;
+ }
+
+ while (c < n)
{
- 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++;
- }
- }
+ itemset[itemsetsize] = core[c];
+ itemsetsize++;
+ c++;
}
- while (csp < csend)
- *itemsetend++ = *csp++;
-
-#ifdef DEBUG
- print_closure(n);
-#endif
+ if (trace_flag)
+ print_closure (n);
}
void
-finalize_closure()
-{
- FREE(itemset);
- FREE(ruleset);
- FREE(fderives + ntokens * rulesetsize);
-}
-
-
-
-#ifdef DEBUG
-
-print_closure(n)
-int n;
-{
- register short *isp;
-
- printf("\n\nn = %d\n\n", n);
- for (isp = itemset; isp < itemsetend; isp++)
- printf(" %d\n", *isp);
-}
-
-
-
-print_firsts()
+free_closure (void)
{
- 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]);
-
- rowp = firsts + ((i - ntokens) * varsetsize);
-
- for (j = 0; j < nvars; j++)
- if (BITISSET (rowp, j))
- printf(" %s\n", tags[j + ntokens]);
- }
+ XFREE (itemset);
+ XFREE (ruleset);
+ XFREE (fderives + ntokens * rulesetsize);
}
-
-
-
-print_fderives()
-{
- register int i;
- register int j;
- register unsigned *rp;
-
- printf(_("\n\n\nFDERIVES\n"));
-
- for (i = ntokens; i < nsyms; i++)
- {
- printf(_("\n\n%s derives\n\n"), tags[i]);
- rp = fderives + i * rulesetsize;
-
- for (j = 0; j <= nrules; j++)
- if (BITISSET (rp, j))
- printf(" %d\n", j);
- }
-
- fflush(stdout);
-}
-
-#endif
projects / bison.git / blobdiff