X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/4d56beff96de67083b357bffa76f110166a9b67c..026816664ff8283a55f91915843a8ff0ac5cf86c:/src/reduce.c?ds=inline diff --git a/src/reduce.c b/src/reduce.c index 754b56d0..eea11b1e 100644 --- a/src/reduce.c +++ b/src/reduce.c @@ -1,24 +1,22 @@ /* Grammar reduction for Bison. - Copyright (C) 1988, 1989, 2000, 2001, 2002, 2003, 2005 Free - Software Foundation, Inc. + Copyright (C) 1988-1989, 2000-2003, 2005-2013 Free Software + Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. - Bison is free software; you can redistribute it and/or modify + This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 2, or (at your option) - any later version. + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. - Bison is distributed in the hope that it will be useful, + This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License - along with Bison; see the file COPYING. If not, write to - the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, - Boston, MA 02110-1301, USA. */ + along with this program. If not, see . */ /* Reduce the grammar: Find and eliminate unreachable terminals, @@ -31,12 +29,12 @@ #include "system.h" #include -#include #include "complain.h" #include "files.h" #include "getargs.h" #include "gram.h" +#include "print-xml.h" #include "reader.h" #include "reduce.h" #include "symtab.h" @@ -51,7 +49,7 @@ static bitset P; static bitset V; /* Set of symbols used to define rule precedence (so they are - `useless', but no warning should be issued). */ + 'useless', but no warning should be issued). */ static bitset V1; static rule_number nuseful_productions; @@ -116,14 +114,14 @@ useless_nonterminals (void) { bitset_copy (Np, N); for (r = 0; r < nrules; r++) - if (!bitset_test (P, r) - && useful_production (r, N)) - { - bitset_set (Np, rules[r].lhs->number - ntokens); - bitset_set (P, r); - } + if (!bitset_test (P, r) + && useful_production (r, N)) + { + bitset_set (Np, rules[r].lhs->number - ntokens); + bitset_set (P, r); + } if (bitset_equal_p (N, Np)) - break; + break; Ns = Np; Np = N; N = Ns; @@ -170,37 +168,37 @@ inaccessable_symbols (void) bitset_set (V, accept->number); while (1) - { - rule_number r; - bitset_copy (Vp, V); - for (r = 0; r < nrules; r++) - { - if (!bitset_test (Pp, r) - && bitset_test (P, r) - && bitset_test (V, rules[r].lhs->number)) - { - item_number *rhsp; - for (rhsp = rules[r].rhs; *rhsp >= 0; rhsp++) - if (ISTOKEN (*rhsp) || bitset_test (N, *rhsp - ntokens)) - bitset_set (Vp, *rhsp); - bitset_set (Pp, r); - } - } - if (bitset_equal_p (V, Vp)) - break; - Vs = Vp; - Vp = V; - V = Vs; - } + { + rule_number r; + bitset_copy (Vp, V); + for (r = 0; r < nrules; r++) + { + if (!bitset_test (Pp, r) + && bitset_test (P, r) + && bitset_test (V, rules[r].lhs->number)) + { + item_number *rhsp; + for (rhsp = rules[r].rhs; *rhsp >= 0; rhsp++) + if (ISTOKEN (*rhsp) || bitset_test (N, *rhsp - ntokens)) + bitset_set (Vp, *rhsp); + bitset_set (Pp, r); + } + } + if (bitset_equal_p (V, Vp)) + break; + Vs = Vp; + Vp = V; + V = Vs; + } } bitset_free (V); V = Vp; /* Tokens 0, 1, and 2 are internal to Bison. Consider them useful. */ - bitset_set (V, endtoken->number); /* end-of-input token */ - bitset_set (V, errtoken->number); /* error token */ - bitset_set (V, undeftoken->number); /* some undefined token */ + bitset_set (V, endtoken->number); /* end-of-input token */ + bitset_set (V, errtoken->number); /* error token */ + bitset_set (V, undeftoken->number); /* some undefined token */ bitset_free (P); P = Pp; @@ -213,7 +211,7 @@ inaccessable_symbols (void) symbol_number i; for (i = ntokens; i < nsyms; i++) if (bitset_test (V, i)) - nuseful_nonterminals++; + nuseful_nonterminals++; } nuseless_nonterminals = nvars - nuseful_nonterminals; @@ -222,7 +220,7 @@ inaccessable_symbols (void) rule_number r; for (r = 0; r < nrules; ++r) if (rules[r].precsym != 0) - bitset_set (V1, rules[r].precsym->number); + bitset_set (V1, rules[r].precsym->number); } } @@ -240,7 +238,7 @@ reduce_grammar_tables (void) rule_number r; for (r = 0; r < nrules; r++) rules[r].useful = bitset_test (P, r); - grammar_rules_never_reduced_report (_("useless rule")); + grammar_rules_useless_report (_("rule useless in grammar")); } /* Map the nonterminals to their new index: useful first, useless @@ -258,11 +256,11 @@ reduce_grammar_tables (void) /* Renumber the rules markers in RITEMS. */ for (r = 0; r < nrules; ++r) { - item_number *rhsp = rules[r].rhs; - for (/* Nothing. */; *rhsp >= 0; ++rhsp) - /* Nothing. */; - *rhsp = rule_number_as_item_number (r); - rules[r].number = r; + item_number *rhsp = rules[r].rhs; + for (/* Nothing. */; *rhsp >= 0; ++rhsp) + /* Nothing. */; + *rhsp = rule_number_as_item_number (r); + rules[r].number = r; } nrules -= nuseless_productions; } @@ -273,8 +271,8 @@ reduce_grammar_tables (void) int length; for (r = nrules; r < nrules + nuseless_productions; ++r) { - length = rule_rhs_length (&rules[r]); - nritems -= length + 1; + length = rule_rhs_length (&rules[r]); + nritems -= length + 1; } } } @@ -287,22 +285,23 @@ reduce_grammar_tables (void) static void nonterminals_reduce (void) { - symbol_number i, n; - /* Map the nonterminals to their new index: useful first, useless afterwards. Kept for later report. */ symbol_number *nontermmap = xnmalloc (nvars, sizeof *nontermmap); - n = ntokens; + symbol_number n = ntokens; + symbol_number i; for (i = ntokens; i < nsyms; i++) if (bitset_test (V, i)) nontermmap[i - ntokens] = n++; for (i = ntokens; i < nsyms; i++) if (!bitset_test (V, i)) { - nontermmap[i - ntokens] = n++; - warn_at (symbols[i]->location, _("useless nonterminal: %s"), - symbols[i]->tag); + nontermmap[i - ntokens] = n++; + if (symbols[i]->status != used) + complain (&symbols[i]->location, Wother, + _("nonterminal useless in grammar: %s"), + symbols[i]->tag); } @@ -323,11 +322,11 @@ nonterminals_reduce (void) rule_number r; for (r = 0; r < nrules; ++r) { - item_number *rhsp; - for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp) - if (ISVAR (*rhsp)) - *rhsp = symbol_number_as_item_number (nontermmap[*rhsp - - ntokens]); + item_number *rhsp; + for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp) + if (ISVAR (*rhsp)) + *rhsp = symbol_number_as_item_number (nontermmap[*rhsp + - ntokens]); } accept->number = nontermmap[accept->number - ntokens]; } @@ -349,9 +348,9 @@ reduce_output (FILE *out) if (nuseless_nonterminals > 0) { int i; - fprintf (out, "%s\n\n", _("Useless nonterminals")); + fprintf (out, "%s\n\n", _("Nonterminals useless in grammar")); for (i = 0; i < nuseless_nonterminals; ++i) - fprintf (out, " %s\n", symbols[nsyms + i]->tag); + fprintf (out, " %s\n", symbols[nsyms + i]->tag); fputs ("\n\n", out); } @@ -359,26 +358,23 @@ reduce_output (FILE *out) bool b = false; int i; for (i = 0; i < ntokens; i++) - if (!bitset_test (V, i) && !bitset_test (V1, i)) - { - if (!b) - fprintf (out, "%s\n\n", _("Terminals which are not used")); - b = true; - fprintf (out, " %s\n", symbols[i]->tag); - } + if (reduce_token_unused_in_grammar (i)) + { + if (!b) + fprintf (out, "%s\n\n", _("Terminals unused in grammar")); + b = true; + fprintf (out, " %s\n", symbols[i]->tag); + } if (b) fputs ("\n\n", out); } if (nuseless_productions > 0) - grammar_rules_partial_print (out, _("Useless rules"), - rule_useless_p); + grammar_rules_partial_print (out, _("Rules useless in grammar"), + rule_useless_in_grammar_p); } - - - /*-------------------------------. | Report the results to STDERR. | `-------------------------------*/ @@ -386,29 +382,16 @@ reduce_output (FILE *out) static void reduce_print (void) { - if (yacc_flag && nuseless_productions) - fprintf (stderr, ngettext ("%d rule never reduced\n", - "%d rules never reduced\n", - nuseless_productions), - nuseless_productions); - - fprintf (stderr, "%s: %s: ", grammar_file, _("warning")); - if (nuseless_nonterminals > 0) - fprintf (stderr, ngettext ("%d useless nonterminal", - "%d useless nonterminals", - nuseless_nonterminals), - nuseless_nonterminals); - - if (nuseless_nonterminals > 0 && nuseless_productions > 0) - fprintf (stderr, _(" and ")); - + complain (NULL, Wother, ngettext ("%d nonterminal useless in grammar", + "%d nonterminals useless in grammar", + nuseless_nonterminals), + nuseless_nonterminals); if (nuseless_productions > 0) - fprintf (stderr, ngettext ("%d useless rule", - "%d useless rules", - nuseless_productions), - nuseless_productions); - fprintf (stderr, "\n"); + complain (NULL, Wother, ngettext ("%d rule useless in grammar", + "%d rules useless in grammar", + nuseless_productions), + nuseless_productions); } void @@ -433,9 +416,9 @@ reduce_grammar (void) reduce_print (); if (!bitset_test (N, accept->number - ntokens)) - fatal_at (startsymbol_location, - _("start symbol %s does not derive any sentence"), - startsymbol->tag); + complain (&startsymbol_location, fatal, + _("start symbol %s does not derive any sentence"), + startsymbol->tag); /* First reduce the nonterminals, as they renumber themselves in the whole grammar. If you change the order, nonterms would be @@ -449,12 +432,25 @@ reduce_grammar (void) { grammar_dump (stderr, "Reduced Grammar"); - fprintf (stderr, "reduced %s defines %d terminals, %d nonterminals\ -, and %d productions.\n", - grammar_file, ntokens, nvars, nrules); + fprintf (stderr, "reduced %s defines %d terminals, %d nonterminals" + ", and %d productions.\n", + grammar_file, ntokens, nvars, nrules); } } +bool +reduce_token_unused_in_grammar (symbol_number i) +{ + aver (i < ntokens); + return !bitset_test (V, i) && !bitset_test (V1, i); +} + +bool +reduce_nonterminal_useless_in_grammar (symbol_number i) +{ + aver (ntokens <= i && i < nsyms + nuseless_nonterminals); + return nsyms <= i; +} /*-----------------------------------------------------------. | Free the global sets used to compute the reduced grammar. |