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* src/reduce.c: Convert to use bitset.h, not hand coded BSet.

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This commit is contained in:
Akim Demaille
2002-03-04 12:01:44 +00:00
parent dfdb1797c3
commit ed86e78c90
2 changed files with 64 additions and 81 deletions
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4
ChangeLog
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@@ -1,3 +1,7 @@
2002-03-04 Akim Demaille <akim@epita.fr>
* src/reduce.c: Convert to use bitset.h, not hand coded BSet.
2002-03-04 Akim Demaille <akim@epita.fr>
* src/closure.c (ruleset): Be a bitset.

141
src/reduce.c
View File

@@ -34,62 +34,35 @@
#include "reduce.h"
#include "reader.h"
#include "getargs.h"
#include "bitset.h"
typedef unsigned *BSet;
typedef short *rule;
/* Set of all nonterminals which are not useless. */
static BSet N;
static bitset N;
/* Set of all rules which have no useless nonterminals in their RHS. */
static BSet P;
static bitset P;
/* Set of all accessible symbols. */
static BSet V;
static bitset V;
/* Set of symbols used to define rule precedence (so they are
`useless', but no warning should be issued). */
static BSet V1;
static bitset V1;
static int nuseful_productions;
static int nuseless_productions;
static int nuseful_nonterminals;
int nuseless_nonterminals;
static bool
bits_equal (BSet L, BSet R, int n)
{
int i;
for (i = n - 1; i >= 0; i--)
if (L[i] != R[i])
return FALSE;
return TRUE;
}
static int
nbits (unsigned i)
{
int count = 0;
while (i != 0)
{
i ^= (i & ((unsigned) (-(int) i)));
++count;
}
return count;
}
static int
bits_size (BSet S, int n)
bits_size (bitset S)
{
int i, count = 0;
for (i = n - 1; i >= 0; i--)
count += nbits (S[i]);
BITSET_EXECUTE (S, 0, i, { ++count; });
return count;
}
@@ -100,7 +73,7 @@ bits_size (BSet S, int n)
`-------------------------------------------------------------------*/
static bool
useful_production (int i, BSet N0)
useful_production (int i, bitset N0)
{
rule r;
short n;
@@ -110,7 +83,7 @@ useful_production (int i, BSet N0)
for (r = &ritem[rules[i].rhs]; *r >= 0; r++)
if (ISVAR (n = *r))
if (!BITISSET (N0, n - ntokens))
if (!bitset_test (N0, n - ntokens))
return FALSE;
return TRUE;
}
@@ -123,13 +96,15 @@ useful_production (int i, BSet N0)
static void
useless_nonterminals (void)
{
BSet Np, Ns;
bitset Np, Ns;
int i;
/* N is set as built. Np is set being built this iteration. P is
set of all productions which have a RHS all in N. */
Np = XCALLOC (unsigned, WORDSIZE (nvars));
Np = bitset_create (nvars, BITSET_FIXED);
bitset_zero (Np);
/* The set being computed is a set of nonterminals which can derive
the empty string or strings consisting of all terminals. At each
@@ -149,26 +124,25 @@ useless_nonterminals (void)
while (1)
{
for (i = WORDSIZE (nvars) - 1; i >= 0; i--)
Np[i] = N[i];
bitset_copy (Np, N);
for (i = 1; i <= nrules; i++)
{
if (!BITISSET (P, i))
if (!bitset_test (P, i))
{
if (useful_production (i, N))
{
SETBIT (Np, rules[i].lhs - ntokens);
SETBIT (P, i);
bitset_set (Np, rules[i].lhs - ntokens);
bitset_set (P, i);
}
}
}
if (bits_equal (N, Np, WORDSIZE (nvars)))
if (bitset_equal_p (N, Np))
break;
Ns = Np;
Np = N;
N = Ns;
}
XFREE (N);
bitset_free (N);
N = Np;
}
@@ -176,7 +150,7 @@ useless_nonterminals (void)
static void
inaccessable_symbols (void)
{
BSet Vp, Vs, Pp;
bitset Vp, Vs, Pp;
int i;
short t;
rule r;
@@ -204,31 +178,32 @@ inaccessable_symbols (void)
terminals are printed (if running in verbose mode) so that the
user can know. */
Vp = XCALLOC (unsigned, WORDSIZE (nsyms));
Pp = XCALLOC (unsigned, WORDSIZE (nrules + 1));
Vp = bitset_create (nsyms, BITSET_FIXED);
bitset_zero (Vp);
Pp = bitset_create (nrules + 1, BITSET_FIXED);
bitset_zero (Pp);
/* If the start symbol isn't useful, then nothing will be useful. */
if (BITISSET (N, start_symbol - ntokens))
if (bitset_test (N, start_symbol - ntokens))
{
SETBIT (V, start_symbol);
bitset_set (V, start_symbol);
while (1)
{
for (i = WORDSIZE (nsyms) - 1; i >= 0; i--)
Vp[i] = V[i];
bitset_copy (Vp, V);
for (i = 1; i <= nrules; i++)
{
if (!BITISSET (Pp, i)
&& BITISSET (P, i)
&& BITISSET (V, rules[i].lhs))
if (!bitset_test (Pp, i)
&& bitset_test (P, i)
&& bitset_test (V, rules[i].lhs))
{
for (r = &ritem[rules[i].rhs]; *r >= 0; r++)
if (ISTOKEN (t = *r) || BITISSET (N, t - ntokens))
SETBIT (Vp, t);
SETBIT (Pp, i);
if (ISTOKEN (t = *r) || bitset_test (N, t - ntokens))
bitset_set (Vp, t);
bitset_set (Pp, i);
}
}
if (bits_equal (V, Vp, WORDSIZE (nsyms)))
if (bitset_equal_p (V, Vp))
break;
Vs = Vp;
Vp = V;
@@ -236,30 +211,30 @@ inaccessable_symbols (void)
}
}
XFREE (V);
bitset_free (V);
V = Vp;
/* Tokens 0, 1, and 2 are internal to Bison. Consider them useful. */
SETBIT (V, 0); /* end-of-input token */
SETBIT (V, 1); /* error token */
SETBIT (V, 2); /* some undefined token */
bitset_set (V, 0); /* end-of-input token */
bitset_set (V, 1); /* error token */
bitset_set (V, 2); /* some undefined token */
XFREE (P);
bitset_free (P);
P = Pp;
nuseful_productions = bits_size (P, WORDSIZE (nrules + 1));
nuseful_productions = bits_size (P);
nuseless_productions = nrules - nuseful_productions;
nuseful_nonterminals = 0;
for (i = ntokens; i < nsyms; i++)
if (BITISSET (V, i))
if (bitset_test (V, i))
nuseful_nonterminals++;
nuseless_nonterminals = nvars - nuseful_nonterminals;
/* A token that was used in %prec should not be warned about. */
for (i = 1; i < nrules; i++)
if (rules[i].precsym != 0)
SETBIT (V1, rules[i].precsym);
bitset_set (V1, rules[i].precsym);
}
static void
@@ -284,7 +259,7 @@ reduce_grammar_tables (void)
np = 0;
ni = 0;
for (pn = 1; pn <= nrules; pn++)
if (BITISSET (P, pn))
if (bitset_test (P, pn))
{
np++;
if (pn != np)
@@ -324,7 +299,7 @@ reduce_grammar_tables (void)
{
int pn;
for (pn = 1; pn <= nrules; pn++)
rules[pn].useful = BITISSET (P, pn);
rules[pn].useful = bitset_test (P, pn);
}
}
@@ -344,10 +319,10 @@ nonterminals_reduce (void)
short *nontermmap = XCALLOC (short, nvars) - ntokens;
n = ntokens;
for (i = ntokens; i < nsyms; i++)
if (BITISSET (V, i))
if (bitset_test (V, i))
nontermmap[i] = n++;
for (i = ntokens; i < nsyms; i++)
if (!BITISSET (V, i))
if (!bitset_test (V, i))
nontermmap[i] = n++;
@@ -405,7 +380,7 @@ reduce_output (FILE *out)
bool b = FALSE;
int i;
for (i = 0; i < ntokens; i++)
if (!BITISSET (V, i) && !BITISSET (V1, i))
if (!bitset_test (V, i) && !bitset_test (V1, i))
{
if (!b)
fprintf (out, "%s\n\n", _("Terminals which are not used:"));
@@ -523,10 +498,14 @@ reduce_grammar (void)
/* Allocate the global sets used to compute the reduced grammar */
N = XCALLOC (unsigned, WORDSIZE (nvars));
P = XCALLOC (unsigned, WORDSIZE (nrules + 1));
V = XCALLOC (unsigned, WORDSIZE (nsyms));
V1 = XCALLOC (unsigned, WORDSIZE (nsyms));
N = bitset_create (nvars, BITSET_FIXED);
bitset_zero (N);
P = bitset_create (nrules + 1, BITSET_FIXED);
bitset_zero (P);
V = bitset_create (nsyms, BITSET_FIXED);
bitset_zero (V);
V1 = bitset_create (nsyms, BITSET_FIXED);
bitset_zero (V1);
useless_nonterminals ();
inaccessable_symbols ();
@@ -538,7 +517,7 @@ reduce_grammar (void)
reduce_print ();
if (!BITISSET (N, start_symbol - ntokens))
if (!bitset_test (N, start_symbol - ntokens))
fatal (_("Start symbol %s does not derive any sentence"),
symbols[start_symbol]->tag);
@@ -564,8 +543,8 @@ reduce_grammar (void)
void
reduce_free (void)
{
XFREE (N);
XFREE (V);
XFREE (V1);
XFREE (P);
bitset_free (N);
bitset_free (V);
bitset_free (V1);
bitset_free (P);
}