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* src/gram.h, src/gram.c (rules_swap): New.
(ritem_longest_rhs): Use it. * src/gram.h (rule_t): `number' is a new member. * src/reader.c (packgram): Set it. * src/reduce.c (reduce_grammar_tables): Move the useless rules at the end of `rules', and count them out of `nrules'. (reduce_output, dump_grammar): Adjust. * src/print.c (print_grammar): It is no longer needed to check for the usefulness of a rule, as useless rules are beyond `nrules + 1'. * tests/reduce.at (Reduced Automaton): New test.
This commit is contained in:
Akim Demaille
402
ChangeLog
402
ChangeLog
@@ -1,3 +1,405 @@
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2002-04-07 Akim Demaille <akim@epita.fr>
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* src/gram.h, src/gram.c (rules_swap): New.
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(ritem_longest_rhs): Use it.
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* src/gram.h (rule_t): `number' is a new member.
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* src/reader.c (packgram): Set it.
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* src/reduce.c (reduce_grammar_tables): Move the useless rules at
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the end of `rules', and count them out of `nrules'.
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(reduce_output, dump_grammar): Adjust.
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* src/print.c (print_grammar): It is no longer needed to check for
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the usefulness of a rule, as useless rules are beyond `nrules + 1'.
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* tests/reduce.at (Reduced Automaton): New test.
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diff -ur -x*.po -x Makefile -x *.pot -x configure* -x TODO bison-1.49a/src/gram.c bison/src/gram.c
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--- bison-1.49a/src/gram.c Sun Apr 7 17:36:56 2002
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+++ bison/src/gram.c Sun Apr 7 18:36:42 2002
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2input grammar variables for bison,
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- Copyright 1984, 1986, 1989, 2001 Free Software Foundation, Inc.
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+ Copyright 1984, 1986, 1989, 2001, 2002 Free Software Foundation, Inc.
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This file is part of Bison, the GNU Compiler Compiler.
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1_number;
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+/*--------------------------------------.
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+| Return the number of symbols in RHS. |
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+`--------------------------------------*/
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+
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+int
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+rule_rhs_length (rule_t *rule)
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+{
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+ int res = 0;
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+ short *rhsp;
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+ for (rhsp = rule->rhs; *rhsp >= 0; ++rhsp)
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+ ++res;
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+ return res;
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+}
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+
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+
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/*------------------------.
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| Dump RITEM for traces. |
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`------------------------*/
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6ngest_rhs (void)
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{
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- int length;
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- int max;
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+ int max = 0;
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int i;
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- length = 0;
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- max = 0;
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- for (i = 0; i < nritems; ++i)
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- if (ritem[i] >= 0)
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- {
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- length++;
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- }
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- else
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- {
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- if (length > max)
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- max = length;
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- length = 0;
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- }
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+ for (i = 1; i < nrules + 1; ++i)
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+ {
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+ int length = rule_rhs_length (&rules[i]);
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+ if (length > max)
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+ max = length;
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+ }
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return max;
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}
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diff -ur -x*.po -x Makefile -x *.pot -x configure* -x TODO bison-1.49a/src/gram.h bison/src/gram.h
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--- bison-1.49a/src/gram.h Sun Apr 7 17:55:00 2002
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+++ bison/src/gram.h Sun Apr 7 18:36:42 2002
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0ule_s
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{
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+ /* The number of the rule in the source. It is usually the index in
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+ RULES too, except if there are useless rules. */
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+ short number;
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+
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short lhs;
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short *rhs;
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short prec;
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0r_token_number;
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+/* Report the length of the RHS. */
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+int rule_rhs_length PARAMS ((rule_t *rule));
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/* Dump RITEM for traces. */
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void ritem_print PARAMS ((FILE *out));
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diff -ur -x*.po -x Makefile -x *.pot -x configure* -x TODO bison-1.49a/src/print.c bison/src/print.c
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--- bison-1.49a/src/print.c Sun Apr 7 17:55:00 2002
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+++ bison/src/print.c Sun Apr 7 18:19:39 2002
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17%s\n\n", _("Grammar"));
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fprintf (out, " %s\n", _("Number, Line, Rule"));
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for (i = 1; i < nrules + 1; i++)
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- /* Don't print rules disabled in reduce_grammar_tables. */
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- if (rules[i].useful)
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- {
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- fprintf (out, _(" %3d %3d %s ->"),
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- i - 1, rules[i].line, escape (symbols[rules[i].lhs]->tag));
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- rule = rules[i].rhs;
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- if (*rule >= 0)
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- while (*rule >= 0)
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- fprintf (out, " %s", escape (symbols[*rule++]->tag));
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- else
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- fprintf (out, " /* %s */", _("empty"));
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- fputc ('\n', out);
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- }
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+ {
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+ fprintf (out, _(" %3d %3d %s ->"),
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+ i - 1, rules[i].line, escape (symbols[rules[i].lhs]->tag));
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+ rule = rules[i].rhs;
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+ if (*rule >= 0)
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+ while (*rule >= 0)
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+ fprintf (out, " %s", escape (symbols[*rule++]->tag));
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+ else
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+ fprintf (out, " /* %s */", _("empty"));
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+ fputc ('\n', out);
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+ }
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fputs ("\n\n", out);
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diff -ur -x*.po -x Makefile -x *.pot -x configure* -x TODO bison-1.49a/src/reader.c bison/src/reader.c
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--- bison-1.49a/src/reader.c Sun Apr 7 17:56:13 2002
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+++ bison/src/reader.c Sun Apr 7 18:19:39 2002
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@@ -1687,6 +1687,7 @@
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while (p)
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{
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bucket *ruleprec = p->ruleprec;
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+ rules[ruleno].number = ruleno;
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rules[ruleno].lhs = p->sym->number;
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rules[ruleno].rhs = ritem + itemno;
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rules[ruleno].line = p->line;
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diff -ur -x*.po -x Makefile -x *.pot -x configure* -x TODO bison-1.49a/src/reduce.c bison/src/reduce.c
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--- bison-1.49a/src/reduce.c Sun Apr 7 17:55:00 2002
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+++ bison/src/reduce.c Sun Apr 7 18:36:42 2002
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2V1, rules[i].precsym);
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}
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+
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+/*-------------------------------------------------------------------.
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+| Put the useless productions at the end of RULES, and adjust NRULES |
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+| accordingly. |
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+`-------------------------------------------------------------------*/
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+
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static void
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reduce_grammar_tables (void)
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{
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- /* This is turned off because we would need to change the numbers in
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- the case statements in the actions file.
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-
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- We don't disable it via CPP so that it is still checked with the
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- rest of the code, to avoid its becoming completely obsolete.
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-
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- FIXME: I think the comment above demonstrates this code must be
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- turned off for *semantic* parser, not in the general case. Try
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- to understand this better --akim. */
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-
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- if (0)
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- /* remove useless productions */
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- if (nuseless_productions > 0)
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- {
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- short np, pn, ni, pi;
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-
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- np = 0;
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- ni = 0;
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- for (pn = 1; pn < nrules + 1; pn++)
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- if (bitset_test (P, pn))
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- {
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- np++;
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- if (pn != np)
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- {
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- rules[np].lhs = rules[pn].lhs;
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- rules[np].line = rules[pn].line;
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- rules[np].prec = rules[pn].prec;
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- rules[np].assoc = rules[pn].assoc;
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- rules[np].rhs = rules[pn].rhs;
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- if (rules[np].rhs - ritem != ni)
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- {
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- pi = rules[np].rhs - ritem;
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- rules[np].rhs = ritem + ni;
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- while (ritem[pi] >= 0)
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- ritem[ni++] = ritem[pi++];
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- ritem[ni++] = -np;
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- }
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- }
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- else
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- {
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- while (ritem[ni++] >= 0)
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- /* Nothing. */;
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- }
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- }
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-
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- ritem[ni] = 0;
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- nrules -= nuseless_productions;
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- nitems = ni;
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- nritems = ni;
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+ /* Flag useless productions. */
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+ {
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+ int pn;
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+ for (pn = 1; pn < nrules + 1; pn++)
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+ rules[pn].useful = bitset_test (P, pn);
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+ }
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|
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- /* Is it worth it to reduce the amount of memory for the
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- grammar? Probably not. */
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|
- }
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+ /* Map the nonterminals to their new index: useful first, useless
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|
+ afterwards. Kept for later report. */
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+ {
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|
+ int useful = 1;
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+ int useless = nrules + 1 - nuseless_productions;
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|
+ rule_t *rules_sorted = XMALLOC (rule_t, nrules + 1) - 1;
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|
+ int i;
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+ for (i = 1; i < nrules + 1; ++i)
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|
+ rules_sorted[rules[i].useful ? useful++ : useless++] = rules[i];
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+ free (rules + 1);
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+ rules = rules_sorted;
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|
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|
- /* Disable useless productions. */
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|
- if (nuseless_productions > 0)
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|
+ /* Also reorder ritems. */
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|
{
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|
- int pn;
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|
- for (pn = 1; pn < nrules + 1; pn++)
|
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|
- rules[pn].useful = bitset_test (P, pn);
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|
+ short *ritems_sorted = XCALLOC (short, nitems + 1);
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|
+ short *ritemsp = ritems_sorted;
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|
+ for (i = 1; i < nrules + 1; ++i)
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|
+ {
|
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|
+ short *rhsp = rules[i].rhs;
|
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|
+ rules[i].rhs = ritemsp;
|
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|
+ for (/* Nothing. */; *rhsp >= 0; ++rhsp)
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|
+ *ritemsp++ = *rhsp;
|
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|
+ *ritemsp++ = -i;
|
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|
+ }
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|
+ *ritemsp++ = 0;
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|
+ free (ritem);
|
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|
+ ritem = ritems_sorted;
|
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|
}
|
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|
+ nrules -= nuseless_productions;
|
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|
+ }
|
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|
+
|
||||||
|
+ /* Adjust NRITEMS and NITEMS. */
|
||||||
|
+ {
|
||||||
|
+ int r;
|
||||||
|
+ int length;
|
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|
+ for (r = nrules + 1; r < nrules + 1 + nuseless_productions; ++r)
|
||||||
|
+ {
|
||||||
|
+ length = rule_rhs_length (&rules[r]);
|
||||||
|
+ nritems -= length + 1;
|
||||||
|
+ nitems -= length + 1;
|
||||||
|
+ }
|
||||||
|
+ }
|
||||||
|
}
|
||||||
|
|
||||||
|
|
||||||
|
@@ -378,16 +372,15 @@
|
||||||
|
{
|
||||||
|
int i;
|
||||||
|
fprintf (out, "%s\n\n", _("Useless rules:"));
|
||||||
|
- for (i = 1; i < nrules + 1; i++)
|
||||||
|
- if (!rules[i].useful)
|
||||||
|
- {
|
||||||
|
- rule r;
|
||||||
|
- fprintf (out, "#%-4d ", i - 1);
|
||||||
|
- fprintf (out, "%s:", symbols[rules[i].lhs]->tag);
|
||||||
|
- for (r = rules[i].rhs; *r >= 0; r++)
|
||||||
|
- fprintf (out, " %s", symbols[*r]->tag);
|
||||||
|
- fputs (";\n", out);
|
||||||
|
- }
|
||||||
|
+ for (i = nrules + 1; i < nuseless_productions + nrules + 1; i++)
|
||||||
|
+ {
|
||||||
|
+ rule r;
|
||||||
|
+ fprintf (out, "#%-4d ", rules[i].number - 1);
|
||||||
|
+ fprintf (out, "%s:", symbols[rules[i].lhs]->tag);
|
||||||
|
+ for (r = rules[i].rhs; *r >= 0; r++)
|
||||||
|
+ fprintf (out, " %s", symbols[*r]->tag);
|
||||||
|
+ fputs (";\n", out);
|
||||||
|
+ }
|
||||||
|
fputs ("\n\n", out);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
@@ -411,7 +404,7 @@
|
||||||
|
fprintf (out, "\n\n");
|
||||||
|
fprintf (out, "Rules\n-----\n\n");
|
||||||
|
fprintf (out, "Num (Prec, Assoc, Useful, Ritem Range) Lhs -> Rhs (Ritem range) [Num]\n");
|
||||||
|
- for (i = 1; i < nrules + 1; i++)
|
||||||
|
+ for (i = 1; i < nrules + nuseless_productions + 1; i++)
|
||||||
|
{
|
||||||
|
int rhs_count = 0;
|
||||||
|
/* Find the last RHS index in ritems. */
|
||||||
|
@@ -429,7 +422,7 @@
|
||||||
|
}
|
||||||
|
fprintf (out, "\n\n");
|
||||||
|
fprintf (out, "Rules interpreted\n-----------------\n\n");
|
||||||
|
- for (i = 1; i < nrules + 1; i++)
|
||||||
|
+ for (i = 1; i < nrules + nuseless_productions + 1; i++)
|
||||||
|
{
|
||||||
|
fprintf (out, "%-5d %s :", i, symbols[rules[i].lhs]->tag);
|
||||||
|
for (r = rules[i].rhs; *r >= 0; r++)
|
||||||
|
2art symbol %s does not derive any sentence"),
|
||||||
|
symbols[start_symbol]->tag);
|
||||||
|
|
||||||
|
- reduce_grammar_tables ();
|
||||||
|
+ if (nuseless_productions > 0)
|
||||||
|
+ reduce_grammar_tables ();
|
||||||
|
if (nuseless_nonterminals > 0)
|
||||||
|
nonterminals_reduce ();
|
||||||
|
|
||||||
|
diff -ur -x*.po -x Makefile -x *.pot -x configure* -x TODO bison-1.49a/tests/reduce.at bison/tests/reduce.at
|
||||||
|
--- bison-1.49a/tests/reduce.at Sun Apr 7 17:36:56 2002
|
||||||
|
+++ bison/tests/reduce.at Sun Apr 7 18:19:39 2002
|
||||||
|
0------- ##
|
||||||
|
+## Reduced Automaton. ##
|
||||||
|
+## ------------------- ##
|
||||||
|
+
|
||||||
|
+# Check that the automaton is that as the for the grammar reduced by
|
||||||
|
+# hand.
|
||||||
|
+
|
||||||
|
+AT_SETUP([Reduced Automaton])
|
||||||
|
+
|
||||||
|
+# The non reduced grammar.
|
||||||
|
+# ------------------------
|
||||||
|
+AT_DATA([[not-reduced.y]],
|
||||||
|
+[[/* A useless token. */
|
||||||
|
+%token useless_token
|
||||||
|
+/* A useful one. */
|
||||||
|
+%token useful
|
||||||
|
+%verbose
|
||||||
|
+%output="not-reduced.c"
|
||||||
|
+
|
||||||
|
+%%
|
||||||
|
+
|
||||||
|
+exp: useful { /* A useful action. */ }
|
||||||
|
+ | non_productive { /* A non productive action. */ }
|
||||||
|
+ ;
|
||||||
|
+
|
||||||
|
+not_reachable: useful { /* A not reachable action. */ }
|
||||||
|
+ ;
|
||||||
|
+
|
||||||
|
+non_productive: non_productive useless_token
|
||||||
|
+ { /* Another non productive action. */ }
|
||||||
|
+ ;
|
||||||
|
+]])
|
||||||
|
+
|
||||||
|
+AT_CHECK([[bison not-reduced.y]], 0, [],
|
||||||
|
+[[not-reduced.y contains 2 useless nonterminals and 3 useless rules
|
||||||
|
+]])
|
||||||
|
+
|
||||||
|
+AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' not-reduced.output]], 0,
|
||||||
|
+[[Useless nonterminals:
|
||||||
|
+ not_reachable
|
||||||
|
+ non_productive
|
||||||
|
+Terminals which are not used:
|
||||||
|
+ useless_token
|
||||||
|
+Useless rules:
|
||||||
|
+#2 exp: non_productive;
|
||||||
|
+#3 not_reachable: useful;
|
||||||
|
+#4 non_productive: non_productive useless_token;
|
||||||
|
+]])
|
||||||
|
+
|
||||||
|
+# The reduced grammar.
|
||||||
|
+# --------------------
|
||||||
|
+AT_DATA([[reduced.y]],
|
||||||
|
+[[/* A useless token. */
|
||||||
|
+%token useless_token
|
||||||
|
+/* A useful one. */
|
||||||
|
+%token useful
|
||||||
|
+%verbose
|
||||||
|
+%output="reduced.c"
|
||||||
|
+
|
||||||
|
+%%
|
||||||
|
+
|
||||||
|
+exp: useful { /* A useful action. */ }
|
||||||
|
+// | non_productive { /* A non productive action. */ } */
|
||||||
|
+ ;
|
||||||
|
+
|
||||||
|
+//not_reachable: useful { /* A not reachable action. */ }
|
||||||
|
+// ;
|
||||||
|
+
|
||||||
|
+//non_productive: non_productive useless_token
|
||||||
|
+// { /* Another non productive action. */ }
|
||||||
|
+// ;
|
||||||
|
+]])
|
||||||
|
+
|
||||||
|
+AT_CHECK([[bison reduced.y]])
|
||||||
|
+
|
||||||
|
+# Comparing the parsers.
|
||||||
|
+cp reduced.c expout
|
||||||
|
+AT_CHECK([sed 's/not-reduced/reduced/g' not-reduced.c], 0, [expout])
|
||||||
|
+
|
||||||
|
+AT_CLEANUP
|
||||||
|
+
|
||||||
|
+
|
||||||
|
+
|
||||||
|
+## ------------------- ##
|
||||||
|
## Underivable Rules. ##
|
||||||
|
## ------------------- ##
|
||||||
|
|
||||||
2002-04-07 Akim Demaille <akim@epita.fr>
|
2002-04-07 Akim Demaille <akim@epita.fr>
|
||||||
|
|
||||||
* src/output.c (output_rule_data): Fix various range errors:
|
* src/output.c (output_rule_data): Fix various range errors:
|
||||||
|
|||||||
Reference in New Issue
Block a user