X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/ff4423cc2856ccc63b0fc72430fdc095208e0b14..3a7456dd96820eea36e9f9656c7f5e29714f78d4:/src/reduce.c diff --git a/src/reduce.c b/src/reduce.c index c5be01fe..87a2a1a9 100644 --- a/src/reduce.c +++ b/src/reduce.c @@ -1,5 +1,5 @@ /* Grammar reduction for Bison. - Copyright 1988, 1989, 2000 Free Software Foundation, Inc. + Copyright 1988, 1989, 2000, 2001 Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -29,7 +29,6 @@ #include "getargs.h" #include "files.h" #include "gram.h" -#include "xalloc.h" #include "complain.h" #include "reduce.h" #include "reader.h" @@ -39,16 +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) @@ -101,7 +107,7 @@ useful_production (int i, BSet N0) /* A production is useful if all of the nonterminals in its appear in the set of useful nonterminals. */ - for (r = &ritem[rrhs[i]]; *r > 0; r++) + for (r = &ritem[rule_table[i].rhs]; *r > 0; r++) if (ISVAR (n = *r)) if (!BITISSET (N0, n - ntokens)) return FALSE; @@ -117,7 +123,7 @@ static void useless_nonterminals (void) { BSet Np, Ns; - int i, n; + 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. */ @@ -140,7 +146,6 @@ useless_nonterminals (void) saved to be used when finding useful productions: only productions in this set will appear in the final grammar. */ - n = 0; while (1) { for (i = WORDSIZE (nvars) - 1; i >= 0; i--) @@ -151,7 +156,7 @@ useless_nonterminals (void) { if (useful_production (i, N)) { - SETBIT (Np, rlhs[i] - ntokens); + SETBIT (Np, rule_table[i].lhs - ntokens); SETBIT (P, i); } } @@ -171,7 +176,7 @@ static void inaccessable_symbols (void) { BSet Vp, Vs, Pp; - int i, n; + int i; short t; rule r; @@ -202,39 +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); - - n = 0; - 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, rlhs[i])) + for (i = WORDSIZE (nsyms) - 1; i >= 0; i--) + Vp[i] = V[i]; + for (i = 1; i <= nrules; i++) { - for (r = &ritem[rrhs[i]]; *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; @@ -258,8 +257,8 @@ 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 @@ -282,15 +281,15 @@ reduce_grammar_tables (void) np++; if (pn != np) { - rlhs[np] = rlhs[pn]; + rule_table[np].lhs = rule_table[pn].lhs; rline[np] = rline[pn]; - rprec[np] = rprec[pn]; - rassoc[np] = rassoc[pn]; - rrhs[np] = rrhs[pn]; - if (rrhs[np] != ni) + 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 = rrhs[np]; - rrhs[np] = ni; + pi = rule_table[np].rhs; + rule_table[np].rhs = ni; while (ritem[pi] >= 0) ritem[ni++] = ritem[pi++]; ritem[ni++] = -np; @@ -311,204 +310,211 @@ reduce_grammar_tables (void) } #endif /* 0 */ - /* Disable useless productions, - since they may contain useless nonterms - that would get mapped below to -1 and confuse everyone. */ + /* Disable useless productions. */ if (nuseless_productions > 0) { int pn; - for (pn = 1; pn <= nrules; pn++) - { - if (!BITISSET (P, pn)) - { - rlhs[pn] = -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. */ +/*------------------------------. +| Remove useless nonterminals. | +`------------------------------*/ - nontermmap = XCALLOC (short, nvars) - ntokens; - for (i = ntokens; i < nsyms; i++) - nontermmap[i] = -1; +static void +nonterminals_reduce (void) +{ + int i, n; + rule r; - n = ntokens; - for (i = ntokens; i < nsyms; i++) - if (BITISSET (V, i)) - nontermmap[i] = n++; + /* Map the nonterminals to their new index: useful first, useless + afterwards. Kept for later report. */ - /* Shuffle elements of tables indexed by symbol number. */ + 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 = 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]); - } - } + 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]; + } - /* Replace all symbol numbers in valid data structures. */ + for (r = ritem; *r; r++) + if (ISVAR (*r)) + *r = nontermmap[*r]; - for (i = 1; i <= nrules; i++) - { - /* Ignore the rules disabled above. */ - if (rlhs[i] >= 0) - rlhs[i] = nontermmap[rlhs[i]]; - if (ISVAR (rprecsym[i])) - /* Can this happen? */ - rprecsym[i] = nontermmap[rprecsym[i]]; - } + start_symbol = nontermmap[start_symbol]; - for (r = ritem; *r; r++) - if (ISVAR (*r)) - *r = nontermmap[*r]; + nsyms -= nuseless_nonterminals; + nvars -= nuseless_nonterminals; - start_symbol = nontermmap[start_symbol]; + free (nontermmap + ntokens); +} - nsyms -= nuseless_nonterminals; - nvars -= nuseless_nonterminals; - free (&nontermmap[ntokens]); - } -} +/*------------------------------------------------------------------. +| Output the detailed results of the reductions. For FILE.output. | +`------------------------------------------------------------------*/ -static void -print_results (void) +void +reduce_output (FILE *out) { - int i; -/* short j; JF unused */ - rule r; - bool b; - if (nuseless_nonterminals > 0) { - obstack_sgrow (&output_obstack, _("Useless nonterminals:")); - obstack_sgrow (&output_obstack, "\n\n"); - for (i = ntokens; i < nsyms; i++) - if (!BITISSET (V, i)) - obstack_fgrow1 (&output_obstack, " %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) - { - obstack_sgrow (&output_obstack, "\n\n"); - obstack_sgrow (&output_obstack, - _("Terminals which are not used:")); - obstack_sgrow (&output_obstack, "\n\n"); - b = TRUE; - } - obstack_fgrow1 (&output_obstack, " %s\n", tags[i]); + 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) { - obstack_sgrow (&output_obstack, "\n\n"); - obstack_sgrow (&output_obstack, _("Useless rules:")); - obstack_sgrow (&output_obstack, "\n\n"); + int i; + fprintf (out, "%s\n\n", _("Useless rules:")); for (i = 1; i <= nrules; i++) - { - if (!BITISSET (P, i)) - { - obstack_fgrow1 (&output_obstack, "#%-4d ", i); - obstack_fgrow1 (&output_obstack, "%s :\t", tags[rlhs[i]]); - for (r = &ritem[rrhs[i]]; *r >= 0; r++) - obstack_fgrow1 (&output_obstack, " %s", tags[*r]); - obstack_sgrow (&output_obstack, ";\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) - obstack_sgrow (&output_obstack, "\n\n"); } -#if 0 /* XXX currently unused. */ static void -dump_grammar (void) +dump_grammar (FILE *out) { int i; rule r; - obstack_fgrow5 (&output_obstack, - "ntokens = %d, nvars = %d, nsyms = %d, nrules = %d, nitems = %d\n\n", - ntokens, nvars, nsyms, nrules, nitems); - obstack_sgrow (&output_obstack, - _("Variables\n---------\n\n")); - obstack_sgrow (&output_obstack, - _("Value Sprec Sassoc Tag\n")); + 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"); for (i = ntokens; i < nsyms; i++) - obstack_fgrow4 (&output_obstack, - "%5d %5d %5d %s\n", i, sprec[i], sassoc[i], tags[i]); - obstack_sgrow (&output_obstack, "\n\n"); - obstack_sgrow (&output_obstack, _("Rules\n-----\n\n")); + 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, "Num (Prec, Assoc, Useful, Ritem Range) Lhs -> Rhs (Ritem range) [Num]\n"); for (i = 1; i <= nrules; i++) { - obstack_fgrow5 (&output_obstack, "%-5d(%5d%5d)%5d : (@%-5d)", - i, rprec[i], rassoc[i], rlhs[i], rrhs[i]); - for (r = &ritem[rrhs[i]]; *r > 0; r++) - obstack_fgrow1 (&output_obstack, "%5d", *r); - obstack_fgrow1 (&output_obstack, " [%d]\n", -(*r)); + 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, "%3d", *r); + fprintf (out, " [%d]\n", -(*r)); } - obstack_sgrow (&output_obstack, "\n\n"); - obstack_sgrow (&output_obstack, - _("Rules interpreted\n-----------------\n\n")); + fprintf (out, "\n\n"); + fprintf (out, "Rules interpreted\n-----------------\n\n"); for (i = 1; i <= nrules; i++) { - obstack_fgrow2 (&output_obstack, "%-5d %s :", i, tags[rlhs[i]]); - for (r = &ritem[rrhs[i]]; *r > 0; r++) - obstack_fgrow1 (&output_obstack, " %s", tags[*r]); - obstack_grow1 (&output_obstack, '\n'); + fprintf (out, "%-5d %s :", i, tags[rule_table[i].lhs]); + for (r = &ritem[rule_table[i].rhs]; *r > 0; r++) + fprintf (out, " %s", tags[*r]); + fputc ('\n', out); } - obstack_sgrow (&output_obstack, "\n\n"); + fprintf (out, "\n\n"); } -#endif + +/*-------------------------------. +| Report the results to STDERR. | +`-------------------------------*/ + static void -print_notices (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); } @@ -530,42 +536,39 @@ reduce_grammar (void) reduced = (bool) (nuseless_nonterminals + nuseless_productions > 0); - if (verbose_flag) - print_results (); - - if (reduced == FALSE) - goto done_reducing; + if (!reduced) + return; - print_notices (); + reduce_print (); if (!BITISSET (N, start_symbol - ntokens)) fatal (_("Start symbol %s does not derive any sentence"), tags[start_symbol]); reduce_grammar_tables (); -#if 0 - if (verbose_flag) + if (nuseless_nonterminals > 0) + nonterminals_reduce (); + + if (trace_flag) { - obstack_fgrow1 (&output_obstack, "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")); - -done_reducing: - /* Free the global sets used to compute the reduced grammar */ +} + +/*-----------------------------------------------------------. +| Free the global sets used to compute the reduced grammar. | +`-----------------------------------------------------------*/ + +void +reduce_free (void) +{ XFREE (N); XFREE (V); + XFREE (V1); XFREE (P); }