X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/f16b08196c780556cbf50691e2944960aebc46f6..a17187e56386747a9b4d9633c3d116c2087f2b8b:/src/tables.c diff --git a/src/tables.c b/src/tables.c index e22b0892..96354b1a 100644 --- a/src/tables.c +++ b/src/tables.c @@ -1,7 +1,7 @@ /* Output the generated parsing program for Bison. - Copyright (C) 1984, 1986, 1989, 1992, 2000, 2001, 2002, 2003, 2004, - 2005, 2006 Free Software Foundation, Inc. + Copyright (C) 1984, 1986, 1989, 1992, 2000-2006, 2009-2012 Free + Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -22,7 +22,6 @@ #include "system.h" #include <bitsetv.h> -#include <quotearg.h> #include "complain.h" #include "conflicts.h" @@ -30,6 +29,7 @@ #include "getargs.h" #include "gram.h" #include "lalr.h" +#include "muscle-tab.h" #include "reader.h" #include "symtab.h" #include "tables.h" @@ -125,7 +125,7 @@ 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; @@ -151,11 +151,11 @@ table_grow (int desired) if (trace_flag & trace_resource) fprintf (stderr, "growing table and check from: %d to %d\n", - old_size, table_size); + old_size, table_size); table = xnrealloc (table, table_size, sizeof *table); conflict_table = xnrealloc (conflict_table, table_size, - sizeof *conflict_table); + sizeof *conflict_table); check = xnrealloc (check, table_size, sizeof *check); for (/* Nothing. */; old_size < table_size; ++old_size) @@ -171,12 +171,12 @@ table_grow (int desired) /*-------------------------------------------------------------------. | For GLR parsers, for each conflicted token in S, as indicated | -| by non-zero entries in CONFLROW, create a list of possible | -| reductions that are alternatives to the shift or reduction | +| by non-zero entries in CONFLROW, create a list of possible | +| reductions that are alternatives to the shift or reduction | | currently recorded for that token in S. Store the alternative | -| reductions followed by a 0 in CONFLICT_LIST, updating | +| reductions followed by a 0 in CONFLICT_LIST, updating | | CONFLICT_LIST_CNT, and storing an index to the start of the list | -| back into CONFLROW. | +| back into CONFLROW. | `-------------------------------------------------------------------*/ static void @@ -191,26 +191,26 @@ conflict_row (state *s) for (j = 0; j < ntokens; j += 1) if (conflrow[j]) { - conflrow[j] = conflict_list_cnt; - - /* 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->lookahead_tokens[i], j) - && (actrow[j] - != rule_number_as_item_number (reds->rules[i]->number))) - { - 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. */ - aver (0 < conflict_list_free); - conflict_list[conflict_list_cnt] = 0; - conflict_list_cnt += 1; - conflict_list_free -= 1; + conflrow[j] = conflict_list_cnt; + + /* 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->lookahead_tokens[i], j) + && (actrow[j] + != rule_number_as_item_number (reds->rules[i]->number))) + { + 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. */ + aver (0 < conflict_list_free); + conflict_list[conflict_list_cnt] = 0; + conflict_list_cnt += 1; + conflict_list_free -= 1; } } @@ -221,9 +221,9 @@ conflict_row (state *s) | 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 | -| ACTION_NUMBER_MINIMUM, a very negative number, means this | -| situation is an error. The parser recognizes this value | -| specially. | +| ACTION_NUMBER_MINIMUM, a very negative number, means this | +| situation is an error. The parser recognizes this value | +| specially. | | | | This is where conflicts are resolved. The loop over lookahead | | rules considered lower-numbered rules last, and the last rule | @@ -239,7 +239,7 @@ 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; @@ -255,22 +255,22 @@ action_row (state *s) int j; bitset_iterator biter; /* loop over all the rules available here which require - lookahead (in reverse order to give precedence to the first - rule) */ + 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->lookahead_tokens[i], j, 0) - { - /* and record this rule as the rule to use if that - token follows. */ - if (actrow[j] != 0) - { - conflicted = true; - conflrow[j] = 1; - } - actrow[j] = rule_number_as_item_number (reds->rules[i]->number); - } + /* and find each token which the rule finds acceptable + to come next */ + BITSET_FOR_EACH (biter, reds->lookahead_tokens[i], j, 0) + { + /* and record this rule as the rule to use if that + token follows. */ + if (actrow[j] != 0) + { + conflicted = true; + conflrow[j] = 1; + } + actrow[j] = rule_number_as_item_number (reds->rules[i]->number); + } } /* Now see which tokens are allowed for shifts in this state. For @@ -282,16 +282,16 @@ action_row (state *s) state *shift_state = trans->states[i]; if (actrow[sym] != 0) - { - conflicted = true; - conflrow[sym] = 1; - } + { + conflicted = true; + conflrow[sym] = 1; + } actrow[sym] = state_number_as_int (shift_state->number); /* Do not use any default reduction if there is a shift for - error */ + error */ if (sym == errtoken->number) - nodefault = true; + nodefault = true; } /* See which tokens are an explicit error in this state (due to @@ -303,62 +303,74 @@ 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 (STRNEQ (default_reductions, "most") && !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; - for (i = 0; i < reds->num; i++) - { - int count = 0; - rule *r = reds->rules[i]; - symbol_number j; - - for (j = 0; j < ntokens; j++) - if (actrow[j] == rule_number_as_item_number (r->number)) - count++; - - if (count > max) - { - max = count; - default_rule = r; - } - } - - /* GLR parsers need space for conflict lists, so we can't - default conflicted entries. For non-conflicted entries - or as long as we are not building a GLR parser, - actions that match the default are replaced with zero, - which means "use the default". */ - - if (max > 0) - { - int j; - for (j = 0; j < ntokens; j++) - if (actrow[j] == rule_number_as_item_number (default_rule->number) - && ! (nondeterministic_parser && conflrow[j])) - actrow[j] = 0; - } - } + { + int max = 0; + for (i = 0; i < reds->num; i++) + { + int count = 0; + rule *r = reds->rules[i]; + symbol_number j; + + for (j = 0; j < ntokens; j++) + if (actrow[j] == rule_number_as_item_number (r->number)) + count++; + + if (count > max) + { + max = count; + default_reduction = r; + } + } + + /* GLR parsers need space for conflict lists, so we can't + default conflicted entries. For non-conflicted entries + or as long as we are not building a GLR parser, + actions that match the default are replaced with zero, + which means "use the default". */ + + if (max > 0) + { + int j; + for (j = 0; j < ntokens; j++) + 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; + actrow[i] = 0; if (conflicted) conflict_row (s); - return default_rule; + return default_reduction; } @@ -395,10 +407,10 @@ save_row (state_number s) for (i = 0; i < ntokens; i++) if (actrow[i] != 0) { - *sp1++ = i; - *sp2++ = actrow[i]; - if (nondeterministic_parser) - *sp3++ = conflrow[i]; + *sp1++ = i; + *sp2++ = actrow[i]; + if (nondeterministic_parser) + *sp3++ = conflrow[i]; } tally[s] = count; @@ -439,21 +451,21 @@ 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 - really reduced, and which are not because of SR or RR - conflicts. */ + really reduced, and which are not because of SR or RR + conflicts. */ if (!nondeterministic_parser) - { - for (j = 0; j < ntokens; ++j) - if (actrow[j] < 0 && actrow[j] != ACTION_NUMBER_MINIMUM) - rules[item_number_as_rule_number (actrow[j])].useful = true; - if (yydefact[i]) - rules[yydefact[i] - 1].useful = true; - } + { + for (j = 0; j < ntokens; ++j) + if (actrow[j] < 0 && actrow[j] != ACTION_NUMBER_MINIMUM) + rules[item_number_as_rule_number (actrow[j])].useful = true; + if (yydefact[i]) + rules[yydefact[i] - 1].useful = true; + } } free (actrow); @@ -500,8 +512,8 @@ save_column (symbol_number sym, state_number default_state) for (i = begin; i < end; i++) if (to_state[i] != default_state) { - *sp1++ = from_state[i]; - *sp2++ = to_state[i]; + *sp1++ = from_state[i]; + *sp2++ = to_state[i]; } tally[symno] = count; @@ -535,8 +547,8 @@ default_goto (symbol_number sym, size_t state_count[]) for (s = 0; s < nstates; s++) if (state_count[s] > max) { - max = state_count[s]; - default_state = s; + max = state_count[s]; + default_state = s; } return default_state; @@ -586,22 +598,22 @@ sort_actions (void) for (i = 0; i < nvectors; i++) if (tally[i] > 0) { - int k; - int t = tally[i]; - int w = width[i]; - int j = nentries - 1; + int k; + int t = tally[i]; + int w = width[i]; + int j = nentries - 1; - while (j >= 0 && (width[order[j]] < w)) - j--; + while (j >= 0 && (width[order[j]] < w)) + j--; - while (j >= 0 && (width[order[j]] == w) && (tally[order[j]] < t)) - j--; + while (j >= 0 && (width[order[j]] == w) && (tally[order[j]] < t)) + j--; - for (k = nentries - 1; k > j; k--) - order[k + 1] = order[k]; + for (k = nentries - 1; k > j; k--) + order[k + 1] = order[k]; - order[j + 1] = i; - nentries++; + order[j + 1] = i; + nentries++; } } @@ -632,8 +644,8 @@ matching_state (vector_number vector) { int j; for (j = 0; j < t; j += 1) - if (conflict_tos[i][j] != 0) - return -1; + if (conflict_tos[i][j] != 0) + return -1; } for (prev = vector - 1; prev >= 0; prev--) @@ -643,17 +655,17 @@ matching_state (vector_number vector) int match = 1; /* Given how ORDER was computed, if the WIDTH or TALLY is - different, there cannot be a matching state. */ + different, there cannot be a matching state. */ if (width[j] != w || tally[j] != t) - return -1; + return -1; for (k = 0; match && k < t; k++) - if (tos[j][k] != tos[i][k] || froms[j][k] != froms[i][k] - || (conflict_tos[j] != NULL && conflict_tos[j][k] != 0)) - match = 0; + if (tos[j][k] != tos[i][k] || froms[j][k] != froms[i][k] + || (conflict_tos[j] != NULL && conflict_tos[j][k] != 0)) + match = 0; if (match) - return j; + return j; } return -1; @@ -681,39 +693,39 @@ pack_vector (vector_number vector) aver (j < table_size); for (k = 0; ok && k < t; k++) - { - loc = j + state_number_as_int (from[k]); - if (table_size <= loc) - table_grow (loc); + { + loc = j + state_number_as_int (from[k]); + if (table_size <= loc) + table_grow (loc); - if (table[loc] != 0) - ok = false; - } + if (table[loc] != 0) + ok = false; + } for (k = 0; ok && k < vector; k++) - if (pos[k] == j) - ok = false; + if (pos[k] == j) + ok = false; if (ok) - { - for (k = 0; k < t; k++) - { - loc = j + from[k]; - table[loc] = to[k]; - if (nondeterministic_parser && conflict_to != NULL) - conflict_table[loc] = conflict_to[k]; - check[loc] = from[k]; - } - - while (table[lowzero] != 0) - lowzero++; - - if (loc > high) - high = loc; - - aver (BASE_MINIMUM <= j && j <= BASE_MAXIMUM); - return j; - } + { + for (k = 0; k < t; k++) + { + loc = j + from[k]; + table[loc] = to[k]; + if (nondeterministic_parser && conflict_to != NULL) + conflict_table[loc] = conflict_to[k]; + check[loc] = from[k]; + } + + while (table[lowzero] != 0) + lowzero++; + + if (loc > high) + high = loc; + + aver (BASE_MINIMUM <= j && j <= BASE_MAXIMUM); + return j; + } } } @@ -771,11 +783,11 @@ pack_table (void) base_number place; if (s < 0) - /* A new set of state actions, or a nonterminal. */ - place = pack_vector (i); + /* A new set of state actions, or a nonterminal. */ + place = pack_vector (i); else - /* Action of I were already coded for S. */ - place = base[s]; + /* Action of I were already coded for S. */ + place = base[s]; pos[i] = place; base[order[i]] = place; @@ -804,7 +816,7 @@ tables_generate (void) correlated. In particular the signedness is not taken into account. But it's not useless. */ verify (sizeof nstates <= sizeof nvectors - && sizeof nvars <= sizeof nvectors); + && sizeof nvars <= sizeof nvectors); nvectors = state_number_as_int (nstates) + nvars;