X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/68cae94e0b4e83246787fc5a413f085513ae9160..c826013fb38c98861ef0fc5d4dc3fb3fb4f555be:/src/tables.c diff --git a/src/tables.c b/src/tables.c index c938139b..01bccfc7 100644 --- a/src/tables.c +++ b/src/tables.c @@ -1,24 +1,22 @@ /* Output the generated parsing program for Bison. - Copyright (C) 1984, 1986, 1989, 1992, 2000, 2001, 2002, 2003, 2004, - 2005 Free Software Foundation, Inc. + Copyright (C) 1984, 1986, 1989, 1992, 2000-2006, 2009-2010 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 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. + 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 3 of the License, or + (at your option) any later version. - Bison 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. + 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 . */ #include #include "system.h" @@ -32,6 +30,7 @@ #include "getargs.h" #include "gram.h" #include "lalr.h" +#include "muscle-tab.h" #include "reader.h" #include "symtab.h" #include "tables.h" @@ -127,7 +126,7 @@ static int table_size = 32768; base_number *table; base_number *check; /* The value used in TABLE to denote explicit syntax errors - (%nonassoc), a negative infinite. First defaults to ACTION_NUMBER_MININUM, + (%nonassoc), a negative infinite. First defaults to ACTION_NUMBER_MINIMUM, but in order to keep small tables, renumbered as TABLE_ERROR, which is the smallest (non error) value minus 1. */ base_number table_ninf = 0; @@ -198,18 +197,18 @@ conflict_row (state *s) /* Find all reductions for token J, and record all that do not match ACTROW[J]. */ for (i = 0; i < reds->num; i += 1) - if (bitset_test (reds->look_ahead_tokens[i], j) + if (bitset_test (reds->lookahead_tokens[i], j) && (actrow[j] != rule_number_as_item_number (reds->rules[i]->number))) { - assert (0 < conflict_list_free); + aver (0 < conflict_list_free); conflict_list[conflict_list_cnt] = reds->rules[i]->number + 1; conflict_list_cnt += 1; conflict_list_free -= 1; } /* Leave a 0 at the end. */ - assert (0 < conflict_list_free); + aver (0 < conflict_list_free); conflict_list[conflict_list_cnt] = 0; conflict_list_cnt += 1; conflict_list_free -= 1; @@ -219,7 +218,7 @@ conflict_row (state *s) /*------------------------------------------------------------------. | Decide what to do for each type of token if seen as the | -| look-ahead in specified state. The value returned is used as the | +| lookahead in specified state. The value returned is used as the | | default action (yydefact) for the state. In addition, ACTROW is | | filled with what to do for each kind of token, index by symbol | | number, with zero meaning do the default action. The value | @@ -227,7 +226,7 @@ conflict_row (state *s) | situation is an error. The parser recognizes this value | | specially. | | | -| This is where conflicts are resolved. The loop over look-ahead | +| This is where conflicts are resolved. The loop over lookahead | | rules considered lower-numbered rules last, and the last rule | | considered that likes a token gets to handle it. | | | @@ -241,7 +240,7 @@ static rule * action_row (state *s) { int i; - rule *default_rule = NULL; + rule *default_reduction = NULL; reductions *reds = s->reductions; transitions *trans = s->transitions; errs *errp = s->errs; @@ -252,17 +251,17 @@ action_row (state *s) for (i = 0; i < ntokens; i++) actrow[i] = conflrow[i] = 0; - if (reds->look_ahead_tokens) + if (reds->lookahead_tokens) { int j; bitset_iterator biter; /* loop over all the rules available here which require - look-ahead (in reverse order to give precedence to the first + lookahead (in reverse order to give precedence to the first rule) */ for (i = reds->num - 1; i >= 0; --i) /* and find each token which the rule finds acceptable to come next */ - BITSET_FOR_EACH (biter, reds->look_ahead_tokens[i], j, 0) + BITSET_FOR_EACH (biter, reds->lookahead_tokens[i], j, 0) { /* and record this rule as the rule to use if that token follows. */ @@ -305,13 +304,24 @@ action_row (state *s) actrow[sym->number] = ACTION_NUMBER_MINIMUM; } + /* Turn off default reductions where requested by the user. See + state_lookahead_tokens_count in lalr.c to understand when states are + labeled as consistent. */ + { + char *default_reductions = + muscle_percent_define_get ("lr.default-reductions"); + if (0 != strcmp (default_reductions, "all") && !s->consistent) + nodefault = true; + free (default_reductions); + } + /* Now find the most common reduction and make it the default action for this state. */ if (reds->num >= 1 && !nodefault) { if (s->consistent) - default_rule = reds->rules[0]; + default_reduction = reds->rules[0]; else { int max = 0; @@ -328,7 +338,7 @@ action_row (state *s) if (count > max) { max = count; - default_rule = r; + default_reduction = r; } } @@ -342,17 +352,18 @@ action_row (state *s) { int j; for (j = 0; j < ntokens; j++) - if (actrow[j] == rule_number_as_item_number (default_rule->number) + if (actrow[j] + == rule_number_as_item_number (default_reduction->number) && ! (nondeterministic_parser && conflrow[j])) actrow[j] = 0; } } } - /* If have no default rule, the default is an error. + /* If have no default reduction, the default is an error. So replace any action which says "error" with "use default". */ - if (!default_rule) + if (!default_reduction) for (i = 0; i < ntokens; i++) if (actrow[i] == ACTION_NUMBER_MINIMUM) actrow[i] = 0; @@ -360,7 +371,7 @@ action_row (state *s) if (conflicted) conflict_row (s); - return default_rule; + return default_reduction; } @@ -410,7 +421,7 @@ save_row (state_number s) /*------------------------------------------------------------------. | Figure out the actions for the specified state, indexed by | -| look-ahead token type. | +| lookahead token type. | | | | The YYDEFACT table is output now. The detailed info is saved for | | putting into YYTABLE later. | @@ -441,8 +452,8 @@ token_actions (void) for (i = 0; i < nstates; ++i) { - rule *default_rule = action_row (states[i]); - yydefact[i] = default_rule ? default_rule->number + 1 : 0; + rule *default_reduction = action_row (states[i]); + yydefact[i] = default_reduction ? default_reduction->number + 1 : 0; save_row (i); /* Now that the parser was computed, we can find which rules are @@ -673,14 +684,14 @@ pack_vector (vector_number vector) base_number *to = tos[i]; unsigned int *conflict_to = conflict_tos[i]; - assert (t); + aver (t != 0); for (j = lowzero - from[0]; ; j++) { int k; bool ok = true; - assert (j < table_size); + aver (j < table_size); for (k = 0; ok && k < t; k++) { @@ -713,7 +724,7 @@ pack_vector (vector_number vector) if (loc > high) high = loc; - assert (BASE_MINIMUM <= j && j <= BASE_MAXIMUM); + aver (BASE_MINIMUM <= j && j <= BASE_MAXIMUM); return j; } }