X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/d6b771c345a389742bfcd73ff13dac1d4f016c88..d0ee410565c9d7bc876af42583ee092568f44fa8:/src/conflicts.c diff --git a/src/conflicts.c b/src/conflicts.c index 13121f6e..9a02d4bb 100644 --- a/src/conflicts.c +++ b/src/conflicts.c @@ -1,24 +1,22 @@ -/* Find and resolve or report look-ahead conflicts for bison, +/* Find and resolve or report lookahead conflicts for bison, - Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002, 2003, 2004, 2005, 2006 - Free Software Foundation, Inc. + Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002, 2003, 2004, 2005, 2006, + 2007 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 <http://www.gnu.org/licenses/>. */ #include <config.h> #include "system.h" @@ -32,6 +30,7 @@ #include "getargs.h" #include "gram.h" #include "lalr.h" +#include "print-xml.h" #include "reader.h" #include "state.h" #include "symtab.h" @@ -41,9 +40,10 @@ int expected_sr_conflicts = -1; int expected_rr_conflicts = -1; static char *conflicts; static struct obstack solved_conflicts_obstack; +static struct obstack solved_conflicts_xml_obstack; static bitset shift_set; -static bitset look_ahead_set; +static bitset lookahead_set; @@ -74,23 +74,25 @@ log_resolution (rule *r, symbol_number token, case shift_resolution: case right_resolution: obstack_fgrow2 (&solved_conflicts_obstack, - _("\ - Conflict between rule %d and token %s resolved as shift"), + _(" Conflict between rule %d and token %s" + " resolved as shift"), r->number, symbols[token]->tag); break; + case reduce_resolution: case left_resolution: obstack_fgrow2 (&solved_conflicts_obstack, - _("\ - Conflict between rule %d and token %s resolved as reduce"), + _(" Conflict between rule %d and token %s" + " resolved as reduce"), r->number, symbols[token]->tag); break; + case nonassoc_resolution: obstack_fgrow2 (&solved_conflicts_obstack, - _("\ - Conflict between rule %d and token %s resolved as an error"), + _(" Conflict between rule %d and token %s" + " resolved as an error"), r->number, symbols[token]->tag); break; @@ -124,13 +126,87 @@ log_resolution (rule *r, symbol_number token, " (%%right %s)", symbols[token]->tag); break; + case nonassoc_resolution: obstack_fgrow1 (&solved_conflicts_obstack, " (%%nonassoc %s)", symbols[token]->tag); break; } + obstack_sgrow (&solved_conflicts_obstack, ".\n"); + + /* XML report */ + if (xml_flag) + { + /* The description of the resolution. */ + switch (resolution) + { + case shift_resolution: + case right_resolution: + obstack_fgrow2 (&solved_conflicts_xml_obstack, + " <resolution rule=\"%d\" symbol=\"%s\"" + " type=\"shift\">", + r->number, + xml_escape (symbols[token]->tag)); + break; + + case reduce_resolution: + case left_resolution: + obstack_fgrow2 (&solved_conflicts_xml_obstack, + " <resolution rule=\"%d\" symbol=\"%s\"" + " type=\"reduce\">", + r->number, + xml_escape (symbols[token]->tag)); + break; + + case nonassoc_resolution: + obstack_fgrow2 (&solved_conflicts_xml_obstack, + " <resolution rule=\"%d\" symbol=\"%s\"" + " type=\"error\">", + r->number, + xml_escape (symbols[token]->tag)); + break; + } + + /* The reason. */ + switch (resolution) + { + case shift_resolution: + obstack_fgrow2 (&solved_conflicts_xml_obstack, + "%s < %s", + xml_escape_n (0, r->prec->tag), + xml_escape_n (1, symbols[token]->tag)); + break; + + case reduce_resolution: + obstack_fgrow2 (&solved_conflicts_xml_obstack, + "%s < %s", + xml_escape_n (0, symbols[token]->tag), + xml_escape_n (1, r->prec->tag)); + break; + + case left_resolution: + obstack_fgrow1 (&solved_conflicts_xml_obstack, + "%%left %s", + xml_escape (symbols[token]->tag)); + break; + + case right_resolution: + obstack_fgrow1 (&solved_conflicts_xml_obstack, + "%%right %s", + xml_escape (symbols[token]->tag)); + break; + + case nonassoc_resolution: + obstack_fgrow1 (&solved_conflicts_xml_obstack, + "%%nonassoc %s", + xml_escape (symbols[token]->tag)); + break; + } + + obstack_sgrow (&solved_conflicts_xml_obstack, "</resolution>\n"); + } } } @@ -138,7 +214,7 @@ log_resolution (rule *r, symbol_number token, /*------------------------------------------------------------------. | Turn off the shift recorded for the specified token in the | | specified state. Used when we resolve a shift-reduce conflict in | -| favor of the reduction. | +| favor of the reduction or as an error (%nonassoc). | `------------------------------------------------------------------*/ static void @@ -147,7 +223,7 @@ flush_shift (state *s, int token) transitions *trans = s->transitions; int i; - bitset_reset (look_ahead_set, token); + bitset_reset (lookahead_set, token); for (i = 0; i < trans->num; i++) if (!TRANSITION_IS_DISABLED (trans, i) && TRANSITION_SYMBOL (trans, i) == token) @@ -156,15 +232,15 @@ flush_shift (state *s, int token) /*--------------------------------------------------------------------. -| Turn off the reduce recorded for the specified token for the | -| specified look-ahead. Used when we resolve a shift-reduce conflict | -| in favor of the shift. | +| Turn off the reduce recorded for the specified token in the | +| specified lookahead set. Used when we resolve a shift-reduce | +| conflict in favor of the shift or as an error (%nonassoc). | `--------------------------------------------------------------------*/ static void -flush_reduce (bitset look_ahead_tokens, int token) +flush_reduce (bitset lookahead_tokens, int token) { - bitset_reset (look_ahead_tokens, token); + bitset_reset (lookahead_tokens, token); } @@ -174,25 +250,25 @@ flush_reduce (bitset look_ahead_tokens, int token) | rule has a precedence. A conflict is resolved by modifying the | | shift or reduce tables so that there is no longer a conflict. | | | -| RULENO is the number of the look-ahead bitset to consider. | +| RULENO is the number of the lookahead bitset to consider. | | | -| ERRORS can be used to store discovered explicit errors. | +| ERRORS and NERRS can be used to store discovered explicit | +| errors. | `------------------------------------------------------------------*/ static void -resolve_sr_conflict (state *s, int ruleno, symbol **errors) +resolve_sr_conflict (state *s, int ruleno, symbol **errors, int *nerrs) { symbol_number i; reductions *reds = s->reductions; /* Find the rule to reduce by to get precedence of reduction. */ rule *redrule = reds->rules[ruleno]; int redprec = redrule->prec->prec; - bitset look_ahead_tokens = reds->look_ahead_tokens[ruleno]; - int nerrs = 0; + bitset lookahead_tokens = reds->lookahead_tokens[ruleno]; for (i = 0; i < ntokens; i++) - if (bitset_test (look_ahead_tokens, i) - && bitset_test (look_ahead_set, i) + if (bitset_test (lookahead_tokens, i) + && bitset_test (lookahead_set, i) && symbols[i]->prec) { /* Shift-reduce conflict occurs for token number i @@ -206,7 +282,7 @@ resolve_sr_conflict (state *s, int ruleno, symbol **errors) else if (symbols[i]->prec > redprec) { log_resolution (redrule, i, shift_resolution); - flush_reduce (look_ahead_tokens, i); + flush_reduce (lookahead_tokens, i); } else /* Matching precedence levels. @@ -221,7 +297,7 @@ resolve_sr_conflict (state *s, int ruleno, symbol **errors) case right_assoc: log_resolution (redrule, i, right_resolution); - flush_reduce (look_ahead_tokens, i); + flush_reduce (lookahead_tokens, i); break; case left_assoc: @@ -232,25 +308,12 @@ resolve_sr_conflict (state *s, int ruleno, symbol **errors) case non_assoc: log_resolution (redrule, i, nonassoc_resolution); flush_shift (s, i); - flush_reduce (look_ahead_tokens, i); + flush_reduce (lookahead_tokens, i); /* Record an explicit error for this token. */ - errors[nerrs++] = symbols[i]; + errors[(*nerrs)++] = symbols[i]; break; } } - - if (nerrs) - { - /* Some tokens have been explicitly made errors. Allocate a - permanent errs structure for this state, to record them. */ - state_errs_set (s, nerrs, errors); - } - - if (obstack_object_size (&solved_conflicts_obstack)) - { - obstack_1grow (&solved_conflicts_obstack, '\0'); - s->solved_conflicts = obstack_finish (&solved_conflicts_obstack); - } } @@ -258,7 +321,7 @@ resolve_sr_conflict (state *s, int ruleno, symbol **errors) | Solve the S/R conflicts of state S using the | | precedence/associativity, and flag it inconsistent if it still has | | conflicts. ERRORS can be used as storage to compute the list of | -| look-ahead tokens on which S raises a syntax error (%nonassoc). | +| lookahead tokens on which S raises a syntax error (%nonassoc). | `-------------------------------------------------------------------*/ static void @@ -267,31 +330,48 @@ set_conflicts (state *s, symbol **errors) int i; transitions *trans = s->transitions; reductions *reds = s->reductions; + int nerrs = 0; if (s->consistent) return; - bitset_zero (look_ahead_set); + bitset_zero (lookahead_set); FOR_EACH_SHIFT (trans, i) - bitset_set (look_ahead_set, TRANSITION_SYMBOL (trans, i)); + bitset_set (lookahead_set, TRANSITION_SYMBOL (trans, i)); - /* Loop over all rules which require look-ahead in this state. First + /* Loop over all rules which require lookahead in this state. First check for shift-reduce conflict, and try to resolve using precedence. */ for (i = 0; i < reds->num; ++i) if (reds->rules[i]->prec && reds->rules[i]->prec->prec - && !bitset_disjoint_p (reds->look_ahead_tokens[i], look_ahead_set)) - resolve_sr_conflict (s, i, errors); + && !bitset_disjoint_p (reds->lookahead_tokens[i], lookahead_set)) + resolve_sr_conflict (s, i, errors, &nerrs); + + if (nerrs) + { + /* Some tokens have been explicitly made errors. Allocate a + permanent errs structure for this state, to record them. */ + state_errs_set (s, nerrs, errors); + } + if (obstack_object_size (&solved_conflicts_obstack)) + { + obstack_1grow (&solved_conflicts_obstack, '\0'); + s->solved_conflicts = obstack_finish (&solved_conflicts_obstack); + } + if (obstack_object_size (&solved_conflicts_xml_obstack)) + { + obstack_1grow (&solved_conflicts_xml_obstack, '\0'); + s->solved_conflicts_xml = obstack_finish (&solved_conflicts_xml_obstack); + } - /* Loop over all rules which require look-ahead in this state. Check + /* Loop over all rules which require lookahead in this state. Check for conflicts not resolved above. */ for (i = 0; i < reds->num; ++i) { - if (!bitset_disjoint_p (reds->look_ahead_tokens[i], look_ahead_set)) + if (!bitset_disjoint_p (reds->lookahead_tokens[i], lookahead_set)) conflicts[s->number] = 1; - - bitset_or (look_ahead_set, look_ahead_set, reds->look_ahead_tokens[i]); + bitset_or (lookahead_set, lookahead_set, reds->lookahead_tokens[i]); } } @@ -305,13 +385,14 @@ void conflicts_solve (void) { state_number i; - /* List of look-ahead tokens on which we explicitly raise a syntax error. */ + /* List of lookahead tokens on which we explicitly raise a syntax error. */ symbol **errors = xnmalloc (ntokens + 1, sizeof *errors); conflicts = xcalloc (nstates, sizeof *conflicts); shift_set = bitset_create (ntokens, BITSET_FIXED); - look_ahead_set = bitset_create (ntokens, BITSET_FIXED); + lookahead_set = bitset_create (ntokens, BITSET_FIXED); obstack_init (&solved_conflicts_obstack); + obstack_init (&solved_conflicts_xml_obstack); for (i = 0; i < nstates; i++) { @@ -327,6 +408,17 @@ conflicts_solve (void) } +void +conflicts_update_state_numbers (state_number old_to_new[], + state_number nstates_old) +{ + state_number i; + for (i = 0; i < nstates_old; ++i) + if (old_to_new[i] != nstates_old) + conflicts[old_to_new[i]] = conflicts[i]; +} + + /*---------------------------------------------. | Count the number of shift/reduce conflicts. | `---------------------------------------------*/ @@ -342,18 +434,18 @@ count_sr_conflicts (state *s) if (!trans) return 0; - bitset_zero (look_ahead_set); + bitset_zero (lookahead_set); bitset_zero (shift_set); FOR_EACH_SHIFT (trans, i) bitset_set (shift_set, TRANSITION_SYMBOL (trans, i)); for (i = 0; i < reds->num; ++i) - bitset_or (look_ahead_set, look_ahead_set, reds->look_ahead_tokens[i]); + bitset_or (lookahead_set, lookahead_set, reds->lookahead_tokens[i]); - bitset_and (look_ahead_set, look_ahead_set, shift_set); + bitset_and (lookahead_set, lookahead_set, shift_set); - src_count = bitset_count (look_ahead_set); + src_count = bitset_count (lookahead_set); return src_count; } @@ -378,7 +470,7 @@ count_rr_conflicts (state *s, bool one_per_token) int count = 0; int j; for (j = 0; j < reds->num; ++j) - if (bitset_test (reds->look_ahead_tokens[j], i)) + if (bitset_test (reds->lookahead_tokens[j], i)) count++; if (count >= 2) @@ -433,7 +525,7 @@ conflicts_output (FILE *out) /*--------------------------------------------------------. | Total the number of S/R and R/R conflicts. Unlike the | | code in conflicts_output, however, count EACH pair of | -| reductions for the same state and look-ahead as one | +| reductions for the same state and lookahead as one | | conflict. | `--------------------------------------------------------*/ @@ -530,6 +622,7 @@ conflicts_free (void) { free (conflicts); bitset_free (shift_set); - bitset_free (look_ahead_set); + bitset_free (lookahead_set); obstack_free (&solved_conflicts_obstack, NULL); + obstack_free (&solved_conflicts_xml_obstack, NULL); }