X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/b2ed6e5826e772162719db595446b2c58e4ac5d6..b9752825a023753145900b00a3f16394e183be60:/src/reduce.c diff --git a/src/reduce.c b/src/reduce.c index 71448410..d8ea5ed6 100644 --- a/src/reduce.c +++ b/src/reduce.c @@ -38,16 +38,23 @@ 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; static int nuseful_nonterminals; -static int nuseless_nonterminals; +int nuseless_nonterminals; static bool bits_equal (BSet L, BSet R, int n) @@ -200,38 +207,33 @@ inaccessable_symbols (void) Pp = XCALLOC (unsigned, WORDSIZE (nrules + 1)); /* If the start symbol isn't useful, then nothing will be useful. */ - if (!BITISSET (N, start_symbol - ntokens)) - goto end_iteration; - - SETBIT (V, start_symbol); - - while (1) + if (BITISSET (N, start_symbol - ntokens)) { - for (i = WORDSIZE (nsyms) - 1; i >= 0; i--) - Vp[i] = V[i]; - for (i = 1; i <= nrules; i++) + SETBIT (V, start_symbol); + + while (1) { - if (!BITISSET (Pp, i) && BITISSET (P, i) && BITISSET (V, rule_table[i].lhs)) + for (i = WORDSIZE (nsyms) - 1; i >= 0; i--) + Vp[i] = V[i]; + for (i = 1; i <= nrules; i++) { - for (r = &ritem[rule_table[i].rhs]; *r >= 0; r++) + if (!BITISSET (Pp, i) + && BITISSET (P, i) + && BITISSET (V, rule_table[i].lhs)) { - if (ISTOKEN (t = *r) || BITISSET (N, t - ntokens)) - { + for (r = &ritem[rule_table[i].rhs]; *r >= 0; r++) + if (ISTOKEN (t = *r) || BITISSET (N, t - ntokens)) SETBIT (Vp, t); - } + SETBIT (Pp, i); } - SETBIT (Pp, i); } + if (bits_equal (V, Vp, WORDSIZE (nsyms))) + break; + Vs = Vp; + Vp = V; + V = Vs; } - if (bits_equal (V, Vp, WORDSIZE (nsyms))) - { - break; - } - Vs = Vp; - Vp = V; - V = Vs; } -end_iteration: XFREE (V); V = Vp; @@ -255,35 +257,42 @@ end_iteration: /* A token that was used in %prec should not be warned about. */ for (i = 1; i < nrules; i++) - if (rprecsym[i] != 0) - SETBIT (V1, rprecsym[i]); + if (rule_table[i].precsym != 0) + SETBIT (V1, rule_table[i].precsym); } static void reduce_grammar_tables (void) { -/* This is turned off because we would need to change the numbers - in the case statements in the actions file. */ -#if 0 - /* remove useless productions */ - if (nuseless_productions > 0) - { - short np, pn, ni, pi; + /* This is turned off because we would need to change the numbers in + the case statements in the actions file. - np = 0; - ni = 0; - for (pn = 1; pn <= nrules; pn++) - { + We don't disable it via CPP so that it is still checked with the + rest of the code, to avoid its becoming completely obsolete. + + FIXME: I think the comment above demonstrates this code must be + turned off for *semantic* parser, not in the general case. Try + to understand this better --akim. */ + + if (0) + /* remove useless productions */ + if (nuseless_productions > 0) + { + short np, pn, ni, pi; + + np = 0; + ni = 0; + for (pn = 1; pn <= nrules; pn++) if (BITISSET (P, pn)) { np++; if (pn != np) { - rule_table[np].lhs = rule_table[pn].lhs; - rline[np] = rline[pn]; - rprec[np] = rprec[pn]; - rassoc[np] = rassoc[pn]; - rule_table[np].rhs = rule_table[pn].rhs; + rule_table[np].lhs = rule_table[pn].lhs; + rule_table[np].line = rule_table[pn].line; + rule_table[np].prec = rule_table[pn].prec; + rule_table[np].assoc = rule_table[pn].assoc; + rule_table[np].rhs = rule_table[pn].rhs; if (rule_table[np].rhs != ni) { pi = rule_table[np].rhs; @@ -298,179 +307,179 @@ reduce_grammar_tables (void) while (ritem[ni++] >= 0); } } - } - ritem[ni] = 0; - nrules -= nuseless_productions; - nitems = ni; - /* Is it worth it to reduce the amount of memory for the - grammar? Probably not. */ + ritem[ni] = 0; + nrules -= nuseless_productions; + nitems = ni; - } -#endif /* 0 */ - /* Disable useless productions, - since they may contain useless nonterms - that would get mapped below to -1 and confuse everyone. */ + /* Is it worth it to reduce the amount of memory for the + grammar? Probably not. */ + } + + /* Disable useless productions. */ if (nuseless_productions > 0) { int pn; - for (pn = 1; pn <= nrules; pn++) - { - if (!BITISSET (P, pn)) - { - rule_table[pn].lhs = -1; - } - } + rule_table[pn].useful = BITISSET (P, pn); } +} - /* 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++; +/*------------------------------. +| Remove useless nonterminals. | +`------------------------------*/ - /* Shuffle elements of tables indexed by symbol number. */ +static void +nonterminals_reduce (void) +{ + int i, n; + rule r; - for (i = ntokens; i < nsyms; i++) - { - n = nontermmap[i]; - if (n >= 0) - { - sassoc[n] = sassoc[i]; - sprec[n] = sprec[i]; - tags[n] = tags[i]; - } - else - { - free (tags[i]); - } - } + /* Map the nonterminals to their new index: useful first, useless + afterwards. Kept for later report. */ - /* Replace all symbol numbers in valid data structures. */ + short *nontermmap = XCALLOC (short, nvars) - ntokens; + n = ntokens; + for (i = ntokens; i < nsyms; i++) + if (BITISSET (V, i)) + nontermmap[i] = n++; + for (i = ntokens; i < nsyms; i++) + if (!BITISSET (V, i)) + nontermmap[i] = n++; + + + /* Shuffle elements of tables indexed by symbol number. */ + { + short *sassoc_sorted = XMALLOC (short, nvars) - ntokens; + short *sprec_sorted = XMALLOC (short, nvars) - ntokens; + char **tags_sorted = XMALLOC (char *, nvars) - ntokens; + + for (i = ntokens; i < nsyms; i++) + { + n = nontermmap[i]; + sassoc_sorted[n] = sassoc[i]; + sprec_sorted[n] = sprec[i]; + tags_sorted[n] = tags[i]; + } + for (i = ntokens; i < nsyms; i++) + { + sassoc[i] = sassoc_sorted[i]; + sprec[i] = sprec_sorted[i]; + tags[i] = tags_sorted[i]; + } + free (sassoc_sorted + ntokens); + free (sprec_sorted + ntokens); + free (tags_sorted + ntokens); + } + + /* 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 (rprecsym[i])) - /* Can this happen? */ - rprecsym[i] = nontermmap[rprecsym[i]]; - } + for (i = 1; i <= nrules; i++) + { + 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]; + for (r = ritem; *r; r++) + if (ISVAR (*r)) + *r = nontermmap[*r]; - start_symbol = nontermmap[start_symbol]; + start_symbol = nontermmap[start_symbol]; - nsyms -= nuseless_nonterminals; - nvars -= nuseless_nonterminals; + nsyms -= nuseless_nonterminals; + nvars -= nuseless_nonterminals; - free (&nontermmap[ntokens]); - } + free (nontermmap + ntokens); } -/*-----------------------------------------------------------------. -| Ouput the detailed results of the reductions. For FILE.output. | -`-----------------------------------------------------------------*/ +/*------------------------------------------------------------------. +| Output the detailed results of the reductions. For FILE.output. | +`------------------------------------------------------------------*/ void reduce_output (FILE *out) { - int i; - rule r; - bool b; - if (nuseless_nonterminals > 0) { - fprintf (out, _("Useless nonterminals:")); - fprintf (out, "\n\n"); - for (i = ntokens; i < nsyms; i++) - if (!BITISSET (V, i)) - fprintf (out, " %s\n", tags[i]); + int i; + fprintf (out, "%s\n\n", _("Useless nonterminals:")); + for (i = 0; i < nuseless_nonterminals; ++i) + fprintf (out, " %s\n", tags[nsyms + i]); + fputs ("\n\n", out); } - b = FALSE; - for (i = 0; i < ntokens; i++) - { + + { + bool b = FALSE; + int i; + for (i = 0; i < ntokens; i++) if (!BITISSET (V, i) && !BITISSET (V1, i)) { if (!b) - { - fprintf (out, "\n\n"); - fprintf (out, _("Terminals which are not used:")); - fprintf (out, "\n\n"); - b = TRUE; - } + fprintf (out, "%s\n\n", _("Terminals which are not used:")); + b = TRUE; fprintf (out, " %s\n", tags[i]); } - } + if (b) + fputs ("\n\n", out); + } if (nuseless_productions > 0) { - fprintf (out, "\n\n"); - fprintf (out, _("Useless rules:")); - fprintf (out, "\n\n"); + int i; + fprintf (out, "%s\n\n", _("Useless rules:")); for (i = 1; i <= nrules; i++) - { - if (!BITISSET (P, i)) - { - fprintf (out, "#%-4d ", i); - fprintf (out, "%s :\t", tags[rule_table[i].lhs]); - for (r = &ritem[rule_table[i].rhs]; *r >= 0; r++) - fprintf (out, " %s", tags[*r]); - fprintf (out, ";\n"); - } - } + if (!rule_table[i].useful) + { + rule r; + fprintf (out, "#%-4d ", i); + fprintf (out, "%s:", tags[rule_table[i].lhs]); + for (r = &ritem[rule_table[i].rhs]; *r >= 0; r++) + fprintf (out, " %s", tags[*r]); + fputs (";\n", out); + } + fputs ("\n\n", out); } - if (nuseless_nonterminals > 0 || nuseless_productions > 0 || b) - fprintf (out, "\n\n"); } -#if 0 /* XXX currently unused. */ static void dump_grammar (FILE *out) { int i; rule r; + fprintf (out, "REDUCED GRAMMAR\n\n"); fprintf (out, - "ntokens = %d, nvars = %d, nsyms = %d, nrules = %d, nitems = %d\n\n", - ntokens, nvars, nsyms, nrules, nitems); - fprintf (out, _("Variables\n---------\n\n")); - fprintf (out, _("Value Sprec Sassoc Tag\n")); + "ntokens = %d, nvars = %d, nsyms = %d, nrules = %d, nitems = %d\n\n", + ntokens, nvars, nsyms, nrules, nitems); + fprintf (out, "Variables\n---------\n\n"); + fprintf (out, "Value Sprec Sassoc Tag\n"); for (i = ntokens; i < nsyms; i++) - fprintf (out, "%5d %5d %5d %s\n", i, sprec[i], sassoc[i], tags[i]); + fprintf (out, "%5d %5d %5d %s\n", i, sprec[i], sassoc[i], tags[i]); fprintf (out, "\n\n"); - fprintf (out, _("Rules\n-----\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; i++) { - fprintf (out, "%-5d(%5d%5d)%5d : (@%-5d)", - i, rprec[i], rassoc[i], rule_table[i].lhs, rule_table[i].rhs); + int rhs_count = 0; + /* Find the last RHS index in ritems. */ + for (r = &ritem[rule_table[i].rhs]; *r > 0; ++r) + ++rhs_count; + fprintf (out, "%3d (%2d, %2d, %2d, %2d-%2d) %2d ->", + i, + rule_table[i].prec, rule_table[i].assoc, rule_table[i].useful, + rule_table[i].rhs, rule_table[i].rhs + rhs_count - 1, + rule_table[i].lhs); + /* Dumped the RHS. */ for (r = &ritem[rule_table[i].rhs]; *r > 0; r++) - fprintf (out, "%5d", *r); - fprintf (out, " [%d]\n", -(*r)); + fprintf (out, "%3d", *r); + fprintf (out, " [%d]\n", -(*r)); } fprintf (out, "\n\n"); - fprintf (out, _("Rules interpreted\n-----------------\n\n")); + fprintf (out, "Rules interpreted\n-----------------\n\n"); for (i = 1; i <= nrules; i++) { fprintf (out, "%-5d %s :", i, tags[rule_table[i].lhs]); @@ -480,7 +489,6 @@ dump_grammar (FILE *out) } fprintf (out, "\n\n"); } -#endif @@ -492,24 +500,27 @@ static void reduce_print (void) { if (yacc_flag && nuseless_productions) - fprintf (stderr, _("%d rules never reduced\n"), nuseless_productions); + fprintf (stderr, ngettext ("%d rule never reduced\n", + "%d rules never reduced\n", + nuseless_productions), + nuseless_productions); fprintf (stderr, _("%s contains "), infile); if (nuseless_nonterminals > 0) - { - fprintf (stderr, _("%d useless nonterminal%s"), - nuseless_nonterminals, - (nuseless_nonterminals == 1 ? "" : "s")); - } + fprintf (stderr, ngettext ("%d useless nonterminal", + "%d useless nonterminals", + nuseless_nonterminals), + nuseless_nonterminals); + if (nuseless_nonterminals > 0 && nuseless_productions > 0) fprintf (stderr, _(" and ")); if (nuseless_productions > 0) - { - fprintf (stderr, _("%d useless rule%s"), - nuseless_productions, (nuseless_productions == 1 ? "" : "s")); - } + fprintf (stderr, ngettext ("%d useless rule", + "%d useless rules", + nuseless_productions), + nuseless_productions); fprintf (stderr, "\n"); fflush (stderr); } @@ -541,24 +552,17 @@ reduce_grammar (void) tags[start_symbol]); reduce_grammar_tables (); -#if 0 - if (verbose_flag) + if (nuseless_nonterminals > 0) + nonterminals_reduce (); + + if (trace_flag) { - fprintf (out, "REDUCED GRAMMAR\n\n"); - dump_grammar (); + dump_grammar (stderr); + + fprintf (stderr, "reduced %s defines %d terminals, %d nonterminals\ +, and %d productions.\n", + infile, ntokens, nvars, nrules); } -#endif - - if (statistics_flag) - fprintf (stderr, _("reduced %s defines %d terminal%s, %d nonterminal%s\ -, and %d production%s.\n"), - infile, - ntokens, - (ntokens == 1 ? "" : "s"), - nvars, - (nvars == 1 ? "" : "s"), - nrules, - (nrules == 1 ? "" : "s")); }