X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/065fbd27af96e4aa82b5f3354870b0dcfee72ce8..9be0c25bf054b026304e6ec480c3893817625607:/src/conflicts.c diff --git a/src/conflicts.c b/src/conflicts.c index 0bec85c7..e09b6d87 100644 --- a/src/conflicts.c +++ b/src/conflicts.c @@ -1,5 +1,6 @@ /* Find and resolve or report look-ahead conflicts for bison, - Copyright 1984, 1989, 1992, 2000, 2001 Free Software Foundation, Inc. + Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002 + Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -19,8 +20,10 @@ 02111-1307, USA. */ #include "system.h" +#include "bitset.h" #include "complain.h" #include "getargs.h" +#include "symtab.h" #include "files.h" #include "gram.h" #include "state.h" @@ -32,19 +35,98 @@ /* -1 stands for not specified. */ int expected_conflicts = -1; static char *conflicts = NULL; +struct obstack solved_conflicts_obstack; + +static bitset shiftset; +static bitset lookaheadset; -static unsigned *shiftset = NULL; -static unsigned *lookaheadset = NULL; +enum conflict_resolution_e + { + shift_resolution, + reduce_resolution, + left_resolution, + right_resolution, + nonassoc_resolution + }; + + +/*----------------------------------------------------------------. +| Explain how an SR conflict between TOKEN and RULE was resolved: | +| RESOLUTION. | +`----------------------------------------------------------------*/ + static inline void -log_resolution (state_t *state, int LAno, int token, char *resolution) +log_resolution (rule_t *rule, int token, + enum conflict_resolution_e resolution) { - if (verbose_flag) - obstack_fgrow4 (&output_obstack, - _("\ -Conflict in state %d between rule %d and token %s resolved as %s.\n"), - state->number, LAruleno[LAno], tags[token], resolution); + if (report_flag & report_solved_conflicts) + { + /* The description of the resolution. */ + switch (resolution) + { + case shift_resolution: + case left_resolution: + obstack_fgrow2 (&solved_conflicts_obstack, + _("\ + Conflict between rule %d and token %s resolved as shift"), + rule->number, + symbols[token]->tag); + break; + case reduce_resolution: + case right_resolution: + obstack_fgrow2 (&solved_conflicts_obstack, + _("\ + Conflict between rule %d and token %s resolved as reduce"), + rule->number, + symbols[token]->tag); + break; + case nonassoc_resolution: + obstack_fgrow2 (&solved_conflicts_obstack, + _("\ + Conflict between rule %d and token %s resolved as an error"), + rule->number, + symbols[token]->tag); + break; + } + + /* The reason. */ + switch (resolution) + { + case shift_resolution: + obstack_fgrow2 (&solved_conflicts_obstack, + " (%s < %s)", + rule->prec->tag, + symbols[token]->tag); + break; + + case reduce_resolution: + obstack_fgrow2 (&solved_conflicts_obstack, + " (%s < %s)", + symbols[token]->tag, + rule->prec->tag); + break; + + case left_resolution: + obstack_fgrow1 (&solved_conflicts_obstack, + " (%%left %s)", + symbols[token]->tag); + break; + + case right_resolution: + obstack_fgrow1 (&solved_conflicts_obstack, + " (%%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"); + } } @@ -60,7 +142,7 @@ flush_shift (state_t *state, int token) shifts *shiftp = state->shifts; int i; - RESETBIT (lookaheadset, token); + bitset_reset (lookaheadset, token); for (i = 0; i < shiftp->nshifts; i++) if (!SHIFT_IS_DISABLED (shiftp, i) && SHIFT_SYMBOL (shiftp, i) == token) SHIFT_DISABLE (shiftp, i); @@ -74,9 +156,9 @@ flush_shift (state_t *state, int token) `-------------------------------------------------------------------*/ static void -flush_reduce (int lookahead, int token) +flush_reduce (bitset lookaheads, int token) { - RESETBIT (LA (lookahead), token); + bitset_reset (lookaheads, token); } @@ -85,34 +167,38 @@ flush_reduce (int lookahead, int token) | precedence declarations. It has already been checked that the | | rule has a precedence. A conflict is resolved by modifying the | | shift or reduce tables so that there is no longer a conflict. | +| | +| LOOKAHEAD is the number of the lookahead bitset to consider. | `------------------------------------------------------------------*/ static void resolve_sr_conflict (state_t *state, int lookahead) { int i; - /* find the rule to reduce by to get precedence of reduction */ - int redprec = rule_table[LAruleno[lookahead]].prec; - errs *errp = ERRS_ALLOC (ntokens + 1); - short *errtokens = errp->errs; + /* Find the rule to reduce by to get precedence of reduction. */ + rule_t *redrule = state->lookaheads_rule[lookahead]; + int redprec = redrule->prec->prec; + bitset lookaheads = state->lookaheads[lookahead]; + errs *errp = errs_new (ntokens + 1); + errp->nerrs = 0; for (i = 0; i < ntokens; i++) - if (BITISSET (LA (lookahead), i) - && BITISSET (lookaheadset, i) - && sprec[i]) + if (bitset_test (lookaheads, i) + && bitset_test (lookaheadset, i) + && symbols[i]->prec) { /* Shift-reduce conflict occurs for token number i and it has a precedence. The precedence of shifting is that of token i. */ - if (sprec[i] < redprec) + if (symbols[i]->prec < redprec) { - log_resolution (state, lookahead, i, _("reduce")); + log_resolution (redrule, i, reduce_resolution); flush_shift (state, i); } - else if (sprec[i] > redprec) + else if (symbols[i]->prec > redprec) { - log_resolution (state, lookahead, i, _("shift")); - flush_reduce (lookahead, i); + log_resolution (redrule, i, shift_resolution); + flush_reduce (lookaheads, i); } else /* Matching precedence levels. @@ -120,92 +206,96 @@ resolve_sr_conflict (state_t *state, int lookahead) For right association, keep only the shift. For nonassociation, keep neither. */ - switch (sassoc[i]) + switch (symbols[i]->assoc) { case right_assoc: - log_resolution (state, lookahead, i, _("shift")); - flush_reduce (lookahead, i); + log_resolution (redrule, i, right_resolution); + flush_reduce (lookaheads, i); break; case left_assoc: - log_resolution (state, lookahead, i, _("reduce")); + log_resolution (redrule, i, left_resolution); flush_shift (state, i); break; case non_assoc: - log_resolution (state, lookahead, i, _("an error")); + log_resolution (redrule, i, nonassoc_resolution); flush_shift (state, i); - flush_reduce (lookahead, i); + flush_reduce (lookaheads, i); /* Record an explicit error for this token. */ - *errtokens++ = i; + errp->errs[errp->nerrs++] = i; + break; + + case undef_assoc: + assert (symbols[i]->assoc != undef_assoc); break; } } - errp->nerrs = errtokens - errp->errs; /* Some tokens have been explicitly made errors. Allocate a permanent errs structure for this state, to record them. */ - i = (char *) errtokens - (char *) errp; - state->errs = ERRS_ALLOC (i + 1); - memcpy (state->errs, errp, i); + state->errs = errs_dup (errp); free (errp); + + if (obstack_object_size (&solved_conflicts_obstack)) + { + obstack_1grow (&solved_conflicts_obstack, '\0'); + state->solved_conflicts = obstack_finish (&solved_conflicts_obstack); + } } static void set_conflicts (state_t *state) { - int i, j; + int i; shifts *shiftp; if (state->consistent) return; - for (i = 0; i < tokensetsize; i++) - lookaheadset[i] = 0; + bitset_zero (lookaheadset); shiftp = state->shifts; for (i = 0; i < shiftp->nshifts && SHIFT_IS_SHIFT (shiftp, i); i++) if (!SHIFT_IS_DISABLED (shiftp, i)) - SETBIT (lookaheadset, SHIFT_SYMBOL (shiftp, i)); + bitset_set (lookaheadset, SHIFT_SYMBOL (shiftp, i)); /* Loop over all rules which require lookahead in this state. First check for shift-reduce conflict, and try to resolve using - precedence */ + precedence. */ for (i = 0; i < state->nlookaheads; ++i) - if (rule_table[LAruleno[state->lookaheadsp + i]].prec) - for (j = 0; j < tokensetsize; ++j) - if (LA (state->lookaheadsp + i)[j] & lookaheadset[j]) - { - resolve_sr_conflict (state, state->lookaheadsp + i); - break; - } - + if (state->lookaheads_rule[i]->prec + && state->lookaheads_rule[i]->prec->prec + && !bitset_disjoint_p (state->lookaheads[i], lookaheadset)) + { + resolve_sr_conflict (state, i); + break; + } /* Loop over all rules which require lookahead in this state. Check for conflicts not resolved above. */ for (i = 0; i < state->nlookaheads; ++i) { - for (j = 0; j < tokensetsize; ++j) - if (LA (state->lookaheadsp + i)[j] & lookaheadset[j]) - conflicts[state->number] = 1; + if (!bitset_disjoint_p (state->lookaheads[i], lookaheadset)) + conflicts[state->number] = 1; - for (j = 0; j < tokensetsize; ++j) - lookaheadset[j] |= LA (state->lookaheadsp + i)[j]; + bitset_or (lookaheadset, lookaheadset, state->lookaheads[i]); } } void -solve_conflicts (void) +conflicts_solve (void) { - int i; + size_t i; conflicts = XCALLOC (char, nstates); - shiftset = XCALLOC (unsigned, tokensetsize); - lookaheadset = XCALLOC (unsigned, tokensetsize); + shiftset = bitset_create (ntokens, BITSET_FIXED); + lookaheadset = bitset_create (ntokens, BITSET_FIXED); + obstack_init (&solved_conflicts_obstack); for (i = 0; i < nstates; i++) - set_conflicts (state_table[i]); + set_conflicts (states[i]); } @@ -216,33 +306,26 @@ solve_conflicts (void) static int count_sr_conflicts (state_t *state) { - int i, k; + int i; int src_count = 0; shifts *shiftp = state->shifts; if (!shiftp) return 0; - for (i = 0; i < tokensetsize; i++) - { - shiftset[i] = 0; - lookaheadset[i] = 0; - } + bitset_zero (lookaheadset); + bitset_zero (shiftset); for (i = 0; i < shiftp->nshifts && SHIFT_IS_SHIFT (shiftp, i); i++) if (!SHIFT_IS_DISABLED (shiftp, i)) - SETBIT (shiftset, SHIFT_SYMBOL (shiftp, i)); + bitset_set (shiftset, SHIFT_SYMBOL (shiftp, i)); for (i = 0; i < state->nlookaheads; ++i) - for (k = 0; k < tokensetsize; ++k) - lookaheadset[k] |= LA (state->lookaheadsp + i)[k]; + bitset_or (lookaheadset, lookaheadset, state->lookaheads[i]); - for (k = 0; k < tokensetsize; ++k) - lookaheadset[k] &= shiftset[k]; + bitset_and (lookaheadset, lookaheadset, shiftset); - for (i = 0; i < ntokens; i++) - if (BITISSET (lookaheadset, i)) - src_count++; + src_count = bitset_count (lookaheadset); return src_count; } @@ -266,7 +349,7 @@ count_rr_conflicts (state_t *state) int count = 0; int j; for (j = 0; j < state->nlookaheads; ++j) - if (BITISSET (LA (state->lookaheadsp), state->lookaheadsp + j)) + if (bitset_test (state->lookaheads[j], i)) count++; if (count >= 2) @@ -323,13 +406,13 @@ void conflicts_output (FILE *out) { bool printed_sth = FALSE; - int i; + size_t i; for (i = 0; i < nstates; i++) if (conflicts[i]) { fprintf (out, _("State %d contains "), i); - fputs (conflict_report (count_sr_conflicts (state_table[i]), - count_rr_conflicts (state_table[i])), out); + fputs (conflict_report (count_sr_conflicts (states[i]), + count_rr_conflicts (states[i])), out); printed_sth = TRUE; } if (printed_sth) @@ -344,7 +427,7 @@ conflicts_output (FILE *out) void conflicts_print (void) { - int i; + size_t i; /* Is the number of SR conflicts OK? Either EXPECTED_CONFLICTS is not set, and then we want 0 SR, or else it is specified, in which @@ -358,8 +441,8 @@ conflicts_print (void) for (i = 0; i < nstates; i++) if (conflicts[i]) { - src_total += count_sr_conflicts (state_table[i]); - rrc_total += count_rr_conflicts (state_table[i]); + src_total += count_sr_conflicts (states[i]); + rrc_total += count_rr_conflicts (states[i]); } src_ok = src_total == (expected_conflicts == -1 ? 0 : expected_conflicts); @@ -401,138 +484,10 @@ conflicts_print (void) void -print_reductions (FILE *out, state_t *state) -{ - int i; - shifts *shiftp = state->shifts; - errs *errp = state->errs; - int nodefault = 0; - - for (i = 0; i < tokensetsize; i++) - shiftset[i] = 0; - - for (i = 0; i < shiftp->nshifts && SHIFT_IS_SHIFT (shiftp, i); i++) - if (!SHIFT_IS_DISABLED (shiftp, i)) - { - /* if this state has a shift for the error token, don't use a - default rule. */ - if (SHIFT_IS_ERROR (shiftp, i)) - nodefault = 1; - SETBIT (shiftset, SHIFT_SYMBOL (shiftp, i)); - } - - if (errp) - for (i = 0; i < errp->nerrs; i++) - if (errp->errs[i]) - SETBIT (shiftset, errp->errs[i]); - - if (state->nlookaheads == 1 && !nodefault) - { - int k; - int default_rule = LAruleno[state->lookaheadsp]; - - for (k = 0; k < tokensetsize; ++k) - lookaheadset[k] = LA (state->lookaheadsp)[k] & shiftset[k]; - - for (i = 0; i < ntokens; i++) - if (BITISSET (lookaheadset, i)) - fprintf (out, _(" %-4s\t[reduce using rule %d (%s)]\n"), - tags[i], default_rule, - tags[rule_table[default_rule].lhs]); - - fprintf (out, _(" $default\treduce using rule %d (%s)\n\n"), - default_rule, tags[rule_table[default_rule].lhs]); - } - else if (state->nlookaheads >= 1) - { - int cmax = 0; - int default_LA = -1; - int default_rule = 0; - - if (!nodefault) - for (i = 0; i < state->nlookaheads; ++i) - { - int count = 0; - int j, k; - - for (k = 0; k < tokensetsize; ++k) - lookaheadset[k] = LA (state->lookaheadsp + i)[k] & ~shiftset[k]; - - for (j = 0; j < ntokens; j++) - if (BITISSET (lookaheadset, j)) - count++; - - if (count > cmax) - { - cmax = count; - default_LA = state->lookaheadsp + i; - default_rule = LAruleno[state->lookaheadsp + i]; - } - - for (k = 0; k < tokensetsize; ++k) - shiftset[k] |= lookaheadset[k]; - } - - for (i = 0; i < tokensetsize; i++) - shiftset[i] = 0; - - for (i = 0; i < shiftp->nshifts && SHIFT_IS_SHIFT (shiftp, i); i++) - if (!SHIFT_IS_DISABLED (shiftp, i)) - SETBIT (shiftset, SHIFT_SYMBOL (shiftp, i)); - - for (i = 0; i < ntokens; i++) - { - int j; - int defaulted = 0; - int count = BITISSET (shiftset, i); - - for (j = 0; j < state->nlookaheads; ++j) - { - if (BITISSET (LA (state->lookaheadsp + j), i)) - { - if (count == 0) - { - if (state->lookaheadsp + j != default_LA) - fprintf (out, - _(" %-4s\treduce using rule %d (%s)\n"), - tags[i], - LAruleno[state->lookaheadsp + j], - tags[rule_table[LAruleno[state->lookaheadsp + j]].lhs]); - else - defaulted = 1; - - count++; - } - else - { - if (defaulted) - fprintf (out, - _(" %-4s\treduce using rule %d (%s)\n"), - tags[i], - LAruleno[default_LA], - tags[rule_table[LAruleno[default_LA]].lhs]); - defaulted = 0; - fprintf (out, - _(" %-4s\t[reduce using rule %d (%s)]\n"), - tags[i], - LAruleno[state->lookaheadsp + j], - tags[rule_table[LAruleno[state->lookaheadsp + j]].lhs]); - } - } - } - } - - if (default_LA >= 0) - fprintf (out, _(" $default\treduce using rule %d (%s)\n"), - default_rule, tags[rule_table[default_rule].lhs]); - } -} - - -void -free_conflicts (void) +conflicts_free (void) { XFREE (conflicts); - XFREE (shiftset); - XFREE (lookaheadset); + bitset_free (shiftset); + bitset_free (lookaheadset); + obstack_free (&solved_conflicts_obstack, NULL); }