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* src/reduce.c: Various comment/formatting changes.

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(nonterminals_reduce): New, extracted from...
(reduce_grammar_tables): here.
(reduce_grammar): Call nonterminals_reduce.
This commit is contained in:
Akim Demaille
2001-11-30 10:47:56 +00:00
parent 396452de26
commit 002389585a
3 changed files with 84 additions and 68 deletions
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7
ChangeLog
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@@ -1,3 +1,10 @@
2001-11-30 Akim Demaille <akim@epita.fr>
* src/reduce.c: Various comment/formatting changes.
(nonterminals_reduce): New, extracted from...
(reduce_grammar_tables): here.
(reduce_grammar): Call nonterminals_reduce.
2001-11-29 Paul Eggert <eggert@twinsun.com>
* src/bison.simple (YYSTACK_REALLOC): Remove.

3
src/main.c
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@@ -64,8 +64,7 @@ main (int argc, char *argv[])
if (complain_message_count)
exit (1);
/* Find useless nonterminals and productions and reduce the grammar.
In file reduce.c. */
/* Find useless nonterminals and productions and reduce the grammar. */
reduce_grammar ();
/* Record other info about the grammar. In files derives and

142
src/reduce.c
View File

@@ -38,11 +38,18 @@ typedef unsigned *BSet;
typedef short *rule;
/* N is set of all nonterminals which are not useless. P is set of
all rules which have no useless nonterminals in their RHS. V is
the set of all accessible symbols. */
/* Set of all nonterminals which are not useless. */
static BSet N;
static BSet N, P, V, V1;
/* Set of all rules which have no useless nonterminals in their RHS. */
static BSet P;
/* Set of all accessible symbols. */
static BSet V;
/* Set of symbols used to define rule precedence (so they are
`useless', but no warning should be issued). */
static BSet V1;
static int nuseful_productions;
static int nuseless_productions;
@@ -318,71 +325,72 @@ reduce_grammar_tables (void)
}
}
}
/* remove useless symbols */
if (nuseless_nonterminals > 0)
{
int i, n;
/* short j; JF unused */
short *nontermmap;
rule r;
/* Create a map of nonterminal number to new nonterminal
number. -1 in the map means it was useless and is being
eliminated. */
nontermmap = XCALLOC (short, nvars) - ntokens;
for (i = ntokens; i < nsyms; i++)
nontermmap[i] = -1;
n = ntokens;
for (i = ntokens; i < nsyms; i++)
if (BITISSET (V, i))
nontermmap[i] = n++;
/* Shuffle elements of tables indexed by symbol number. */
for (i = ntokens; i < nsyms; i++)
{
n = nontermmap[i];
if (n >= 0)
{
sassoc[n] = sassoc[i];
sprec[n] = sprec[i];
tags[n] = tags[i];
}
}
/* Replace all symbol numbers in valid data structures. */
for (i = 1; i <= nrules; i++)
{
/* Ignore the rules disabled above. */
if (rule_table[i].lhs >= 0)
rule_table[i].lhs = nontermmap[rule_table[i].lhs];
if (ISVAR (rule_table[i].precsym))
/* Can this happen? */
rule_table[i].precsym = nontermmap[rule_table[i].precsym];
}
for (r = ritem; *r; r++)
if (ISVAR (*r))
*r = nontermmap[*r];
start_symbol = nontermmap[start_symbol];
nsyms -= nuseless_nonterminals;
nvars -= nuseless_nonterminals;
free (&nontermmap[ntokens]);
}
}
/*-----------------------------------------------------------------.
| Ouput the detailed results of the reductions. For FILE.output. |
`-----------------------------------------------------------------*/
/*------------------------------.
| Remove useless nonterminals. |
`------------------------------*/
static void
nonterminals_reduce (void)
{
int i, n;
rule r;
/* Create a map of nonterminal number to new nonterminal number. -1
in the map means it was useless and is being eliminated. */
short *nontermmap = XCALLOC (short, nvars) - ntokens;
for (i = ntokens; i < nsyms; i++)
nontermmap[i] = -1;
n = ntokens;
for (i = ntokens; i < nsyms; i++)
if (BITISSET (V, i))
nontermmap[i] = n++;
/* Shuffle elements of tables indexed by symbol number. */
for (i = ntokens; i < nsyms; i++)
{
n = nontermmap[i];
if (n >= 0)
{
sassoc[n] = sassoc[i];
sprec[n] = sprec[i];
tags[n] = tags[i];
}
}
/* Replace all symbol numbers in valid data structures. */
for (i = 1; i <= nrules; i++)
{
/* Ignore the rules disabled above. */
if (rule_table[i].lhs >= 0)
rule_table[i].lhs = nontermmap[rule_table[i].lhs];
if (ISVAR (rule_table[i].precsym))
/* Can this happen? */
rule_table[i].precsym = nontermmap[rule_table[i].precsym];
}
for (r = ritem; *r; r++)
if (ISVAR (*r))
*r = nontermmap[*r];
start_symbol = nontermmap[start_symbol];
nsyms -= nuseless_nonterminals;
nvars -= nuseless_nonterminals;
free (&nontermmap[ntokens]);
}
/*------------------------------------------------------------------.
| Output the detailed results of the reductions. For FILE.output. |
`------------------------------------------------------------------*/
void
reduce_output (FILE *out)
@@ -537,6 +545,8 @@ reduce_grammar (void)
tags[start_symbol]);
reduce_grammar_tables ();
if (nuseless_nonterminals > 0)
nonterminals_reduce ();
if (trace_flag)
{