mirror of
https://git.savannah.gnu.org/git/bison.git
synced 2026-03-10 04:43:03 +00:00
7086e7071e
* lib/bitsetv.h, lib/ebitset.c, lib/ebitset.h, lib/lbitset.c, * lib/lbitset.h, lib/sbitset.c, lib/sbitset.h: New. * src/closure.c (fderives): Be an array of bitsets.
273 lines
6.5 KiB
C
273 lines
6.5 KiB
C
/* Subroutines for bison
|
||
Copyright 1984, 1989, 2000, 2001 Free Software Foundation, Inc.
|
||
|
||
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 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. */
|
||
|
||
#include "system.h"
|
||
#include "getargs.h"
|
||
#include "symtab.h"
|
||
#include "gram.h"
|
||
#include "reader.h"
|
||
#include "closure.h"
|
||
#include "derives.h"
|
||
#include "warshall.h"
|
||
#include "bitset.h"
|
||
|
||
/* NITEMSET is the size of the array ITEMSET. */
|
||
short *itemset;
|
||
int nitemset;
|
||
|
||
static unsigned *ruleset;
|
||
|
||
/* internal data. See comments before set_fderives and set_firsts. */
|
||
static bitset *fderives;
|
||
static unsigned int *firsts;
|
||
|
||
/* Retrieve the FDERIVES/FIRSTS sets of the nonterminals numbered Var. */
|
||
#define FDERIVES(Var) fderives[(Var) - ntokens]
|
||
#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;
|
||
|
||
|
||
/*-----------------.
|
||
| Debugging code. |
|
||
`-----------------*/
|
||
|
||
static void
|
||
print_closure (const char *title, short *array, size_t size)
|
||
{
|
||
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, j;
|
||
|
||
fprintf (stderr, "FIRSTS\n");
|
||
for (i = ntokens; i < nsyms; i++)
|
||
{
|
||
fprintf (stderr, "\t%s firsts\n", symbols[i]->tag);
|
||
for (j = 0; j < nvars; j++)
|
||
if (BITISSET (FIRSTS (i), j))
|
||
fprintf (stderr, "\t\t%d (%s)\n",
|
||
j + ntokens, symbols[j + ntokens]->tag);
|
||
}
|
||
fprintf (stderr, "\n\n");
|
||
}
|
||
|
||
|
||
static void
|
||
print_fderives (void)
|
||
{
|
||
int i;
|
||
int j;
|
||
|
||
fprintf (stderr, "FDERIVES\n");
|
||
|
||
for (i = ntokens; i < nsyms; i++)
|
||
{
|
||
fprintf (stderr, "\t%s derives\n", symbols[i]->tag);
|
||
for (j = 0; j <= nrules; j++)
|
||
if (bitset_test (FDERIVES (i), j))
|
||
{
|
||
short *rhsp;
|
||
fprintf (stderr, "\t\t%d:", j - 1);
|
||
for (rhsp = &ritem[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. |
|
||
`-------------------------------------------------------------------*/
|
||
|
||
static void
|
||
set_firsts (void)
|
||
{
|
||
int i, j;
|
||
|
||
varsetsize = WORDSIZE (nvars);
|
||
|
||
firsts = XCALLOC (unsigned, nvars * varsetsize);
|
||
|
||
for (i = ntokens; i < nsyms; i++)
|
||
for (j = 0; derives[i][j] >= 0; ++j)
|
||
{
|
||
int symbol = ritem[rules[derives[i][j]].rhs];
|
||
if (ISVAR (symbol))
|
||
SETBIT (FIRSTS (i), symbol - ntokens);
|
||
}
|
||
|
||
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. |
|
||
`-------------------------------------------------------------------*/
|
||
|
||
static void
|
||
set_fderives (void)
|
||
{
|
||
int i, j, k;
|
||
|
||
fderives = XCALLOC (bitset, nvars);
|
||
bitset_stats_init ();
|
||
for (i = 0 ; i < nvars; ++i)
|
||
{
|
||
fderives[i] = bitset_create (nrules + 1, BITSET_FIXED);
|
||
bitset_zero (fderives[i]);
|
||
}
|
||
|
||
set_firsts ();
|
||
|
||
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)
|
||
bitset_set (FDERIVES (i), derives[j][k]);
|
||
|
||
if (trace_flag)
|
||
print_fderives ();
|
||
|
||
XFREE (firsts);
|
||
}
|
||
|
||
|
||
void
|
||
new_closure (int n)
|
||
{
|
||
itemset = XCALLOC (short, n);
|
||
|
||
rulesetsize = WORDSIZE (nrules + 1);
|
||
ruleset = XCALLOC (unsigned, rulesetsize);
|
||
|
||
set_fderives ();
|
||
}
|
||
|
||
|
||
|
||
void
|
||
closure (short *core, int n)
|
||
{
|
||
/* Index over CORE. */
|
||
int c;
|
||
|
||
/* An index over RULESET. */
|
||
int r;
|
||
|
||
/* A bit index over RULESET. */
|
||
int ruleno;
|
||
|
||
if (trace_flag)
|
||
print_closure ("input", core, n);
|
||
|
||
if (n == 0)
|
||
{
|
||
for (ruleno = 0; ruleno < nrules + 1; ++ruleno)
|
||
if (bitset_test (FDERIVES (start_symbol), ruleno))
|
||
SETBIT (ruleset, ruleno);
|
||
else
|
||
RESETBIT (ruleset, ruleno);
|
||
}
|
||
else
|
||
{
|
||
for (r = 0; r < rulesetsize; ++r)
|
||
ruleset[r] = 0;
|
||
|
||
for (c = 0; c < n; ++c)
|
||
if (ISVAR (ritem[core[c]]))
|
||
for (ruleno = 0; ruleno < nrules + 1; ++ruleno)
|
||
if (bitset_test (FDERIVES (ritem[core[c]]), ruleno))
|
||
SETBIT (ruleset, ruleno);
|
||
}
|
||
|
||
nitemset = 0;
|
||
c = 0;
|
||
for (ruleno = 0; ruleno < nrules + 1; ++ruleno)
|
||
if (BITISSET (ruleset, ruleno))
|
||
{
|
||
int itemno = rules[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);
|
||
}
|
||
|
||
|
||
void
|
||
free_closure (void)
|
||
{
|
||
int i;
|
||
XFREE (itemset);
|
||
XFREE (ruleset);
|
||
|
||
for (i = 0 ; i < nvars; ++i)
|
||
bitset_free (fderives[i]);
|
||
free (fderives);
|
||
}
|