mirror of
https://git.savannah.gnu.org/git/bison.git
synced 2026-08-18 23:24:26 +00:00
318 lines
6.7 KiB
C
318 lines
6.7 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 "gram.h"
|
|
#include "reader.h"
|
|
#include "closure.h"
|
|
#include "derives.h"
|
|
#include "warshall.h"
|
|
|
|
/* ITEMSETSIZE is the size of the array ITEMSET. */
|
|
short *itemset;
|
|
size_t itemsetsize;
|
|
|
|
static unsigned *ruleset;
|
|
|
|
/* internal data. See comments before set_fderives and set_firsts. */
|
|
static unsigned *fderives;
|
|
static unsigned *firsts;
|
|
|
|
#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;
|
|
|
|
|
|
/*-----------------.
|
|
| Debugging code. |
|
|
`-----------------*/
|
|
|
|
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");
|
|
}
|
|
|
|
|
|
static void
|
|
print_firsts (void)
|
|
{
|
|
int i;
|
|
int j;
|
|
unsigned *rowp;
|
|
|
|
fprintf (stderr, "FIRSTS\n");
|
|
|
|
for (i = ntokens; i < nsyms; i++)
|
|
{
|
|
fprintf (stderr, "\t%s firsts\n", tags[i]);
|
|
|
|
rowp = FIRSTS (i - ntokens);
|
|
|
|
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");
|
|
}
|
|
|
|
|
|
static void
|
|
print_fderives (void)
|
|
{
|
|
int i;
|
|
int j;
|
|
unsigned *rp;
|
|
|
|
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))
|
|
{
|
|
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");
|
|
}
|
|
|
|
/*-------------------------------------------------------------------.
|
|
| 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)
|
|
{
|
|
unsigned *row;
|
|
int symbol;
|
|
short *sp;
|
|
int rowsize;
|
|
|
|
int i;
|
|
|
|
varsetsize = rowsize = WORDSIZE (nvars);
|
|
|
|
firsts = XCALLOC (unsigned, nvars * rowsize);
|
|
|
|
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;
|
|
}
|
|
|
|
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)
|
|
{
|
|
unsigned *rrow;
|
|
unsigned *vrow;
|
|
int j;
|
|
unsigned cword;
|
|
short *rp;
|
|
int b;
|
|
|
|
int ruleno;
|
|
int i;
|
|
|
|
fderives = XCALLOC (unsigned, nvars * rulesetsize) - ntokens * rulesetsize;
|
|
|
|
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;
|
|
}
|
|
|
|
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)
|
|
{
|
|
int ruleno;
|
|
short *csp;
|
|
|
|
int itemno;
|
|
int i;
|
|
|
|
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);
|
|
}
|
|
|
|
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];
|
|
}
|
|
}
|
|
}
|
|
|
|
ruleno = 0;
|
|
itemsetsize = 0;
|
|
csp = core;
|
|
for (i = 0; i < rulesetsize; ++i)
|
|
{
|
|
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++;
|
|
}
|
|
}
|
|
}
|
|
|
|
while (csp < (core + n))
|
|
itemset[itemsetsize++] = *csp++;
|
|
|
|
if (trace_flag)
|
|
print_closure (n);
|
|
}
|
|
|
|
|
|
void
|
|
free_closure (void)
|
|
{
|
|
XFREE (itemset);
|
|
XFREE (ruleset);
|
|
XFREE (fderives + ntokens * rulesetsize);
|
|
}
|