X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/f693ad146e6e4951662d60903b8512d518cb09da..969e2ed98b6b66e1fa2d1e23247644d2057995d9:/src/conflicts.c diff --git a/src/conflicts.c b/src/conflicts.c index 6542c943..22e7d8a3 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" @@ -33,17 +36,21 @@ int expected_conflicts = -1; static char *conflicts = NULL; -static unsigned *shiftset = NULL; -static unsigned *lookaheadset = NULL; +static bitset shiftset; +static bitset lookaheadset; static inline void -log_resolution (int state, int LAno, int token, char *resolution) +log_resolution (state_t *state, int LAno, int token, const char *resolution) { - obstack_fgrow4 (&output_obstack, - _("\ + if (verbose_flag) + obstack_fgrow4 (&output_obstack, + _("\ Conflict in state %d between rule %d and token %s resolved as %s.\n"), - state, LAruleno[LAno], tags[token], resolution); + state->number, + LArule[LAno]->number, + symbols[token]->tag, + resolution); } @@ -54,17 +61,31 @@ Conflict in state %d between rule %d and token %s resolved as %s.\n"), `------------------------------------------------------------------*/ static void -flush_shift (int state, int token) +flush_shift (state_t *state, int token) { - shifts *shiftp = state_table[state]->shifts; + shifts *shiftp = state->shifts; int i; + 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); } +/*-------------------------------------------------------------------. +| Turn off the reduce recorded for the specified token for the | +| specified lookahead. Used when we resolve a shift-reduce conflict | +| in favor of the shift. | +`-------------------------------------------------------------------*/ + +static void +flush_reduce (int lookahead, int token) +{ + bitset_reset (LA[lookahead], token); +} + + /*------------------------------------------------------------------. | Attempt to resolve shift-reduce conflict for one rule by means of | | precedence declarations. It has already been checked that the | @@ -73,144 +94,117 @@ flush_shift (int state, int token) `------------------------------------------------------------------*/ static void -resolve_sr_conflict (int state, int lookaheadnum) +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[lookaheadnum]].prec; - errs *errp = ERRS_ALLOC (ntokens + 1); - short *errtokens = errp->errs; + int redprec = LArule[lookahead]->prec->prec; + errs *errp = errs_new (ntokens + 1); + errp->nerrs = 0; for (i = 0; i < ntokens; i++) - if (BITISSET (LA (lookaheadnum), i) - && BITISSET (lookaheadset, i) - && sprec[i]) - /* Shift-reduce conflict occurs for token number i - and it has a precedence. - The precedence of shifting is that of token i. */ + if (bitset_test (LA[lookahead], i) + && bitset_test (lookaheadset, i) + && symbols[i]->prec) { - if (sprec[i] < redprec) + /* Shift-reduce conflict occurs for token number i + and it has a precedence. + The precedence of shifting is that of token i. */ + if (symbols[i]->prec < redprec) { - log_resolution (state, lookaheadnum, i, _("reduce")); - /* flush the shift for this token */ - RESETBIT (lookaheadset, i); + log_resolution (state, lookahead, i, _("reduce")); flush_shift (state, i); } - else if (sprec[i] > redprec) + else if (symbols[i]->prec > redprec) { - log_resolution (state, lookaheadnum, i, _("shift")); - /* flush the reduce for this token */ - RESETBIT (LA (lookaheadnum), i); + log_resolution (state, lookahead, i, _("shift")); + flush_reduce (lookahead, i); } else - { - /* Matching precedence levels. - For left association, keep only the reduction. - For right association, keep only the shift. - For nonassociation, keep neither. */ - - switch (sassoc[i]) - { - case right_assoc: - log_resolution (state, lookaheadnum, i, _("shift")); - break; - - case left_assoc: - log_resolution (state, lookaheadnum, i, _("reduce")); - break; - - case non_assoc: - log_resolution (state, lookaheadnum, i, _("an error")); - break; - } - - if (sassoc[i] != right_assoc) - { - /* flush the shift for this token */ - RESETBIT (lookaheadset, i); - flush_shift (state, i); - } - if (sassoc[i] != left_assoc) - { - /* flush the reduce for this token */ - RESETBIT (LA (lookaheadnum), i); - } - if (sassoc[i] == non_assoc) - { - /* Record an explicit error for this token. */ - *errtokens++ = i; - } - } + /* Matching precedence levels. + For left association, keep only the reduction. + For right association, keep only the shift. + For nonassociation, keep neither. */ + + switch (symbols[i]->assoc) + { + case right_assoc: + log_resolution (state, lookahead, i, _("shift")); + flush_reduce (lookahead, i); + break; + + case left_assoc: + log_resolution (state, lookahead, i, _("reduce")); + flush_shift (state, i); + break; + + case non_assoc: + log_resolution (state, lookahead, i, _("an error")); + flush_shift (state, i); + flush_reduce (lookahead, i); + /* Record an explicit error for this token. */ + errp->errs[errp->nerrs++] = i; + 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_table[state]->errs = ERRS_ALLOC (i + 1); - memcpy (state_table[state]->errs, errp, i); + state->errs = errs_dup (errp); free (errp); } static void -set_conflicts (int state) +set_conflicts (state_t *state) { - int i, j; + int i; shifts *shiftp; - if (state_table[state]->consistent) + if (state->consistent) return; - for (i = 0; i < tokensetsize; i++) - lookaheadset[i] = 0; + bitset_zero (lookaheadset); - shiftp = state_table[state]->shifts; + 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 */ - for (i = state_table[state]->lookaheads; - i < state_table[state + 1]->lookaheads; - ++i) - if (rule_table[LAruleno[i]].prec) - for (j = 0; j < tokensetsize; ++j) - if (LA (i)[j] & lookaheadset[j]) - { - resolve_sr_conflict (state, i); - break; - } - + for (i = 0; i < state->nlookaheads; ++i) + if (LArule[state->lookaheadsp + i]->prec + && LArule[state->lookaheadsp + i]->prec->prec + && !bitset_disjoint_p (LA[state->lookaheadsp + i], lookaheadset)) + { + resolve_sr_conflict (state, state->lookaheadsp + i); + break; + } /* Loop over all rules which require lookahead in this state. Check for conflicts not resolved above. */ - for (i = state_table[state]->lookaheads; - i < state_table[state + 1]->lookaheads; - ++i) + for (i = 0; i < state->nlookaheads; ++i) { - for (j = 0; j < tokensetsize; ++j) - if (LA (i)[j] & lookaheadset[j]) - conflicts[state] = 1; + if (!bitset_disjoint_p (LA[state->lookaheadsp + i], lookaheadset)) + conflicts[state->number] = 1; - for (j = 0; j < tokensetsize; ++j) - lookaheadset[j] |= LA (i)[j]; + bitset_or (lookaheadset, lookaheadset, LA[state->lookaheadsp + i]); } } void solve_conflicts (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); for (i = 0; i < nstates; i++) - set_conflicts (i); + set_conflicts (states[i]); } @@ -219,37 +213,28 @@ solve_conflicts (void) `---------------------------------------------*/ static int -count_sr_conflicts (int state) +count_sr_conflicts (state_t *state) { - int i, k; + int i; int src_count = 0; - shifts *shiftp = state_table[state]->shifts; + 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 = state_table[state]->lookaheads; - i < state_table[state + 1]->lookaheads; - ++i) - for (k = 0; k < tokensetsize; ++k) - lookaheadset[k] |= LA (i)[k]; + for (i = 0; i < state->nlookaheads; ++i) + bitset_or (lookaheadset, lookaheadset, LA[state->lookaheadsp + 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; } @@ -260,23 +245,20 @@ count_sr_conflicts (int state) `----------------------------------------------*/ static int -count_rr_conflicts (int state) +count_rr_conflicts (state_t *state) { int i; int rrc_count = 0; - int m = state_table[state]->lookaheads; - int n = state_table[state + 1]->lookaheads; - - if (n - m < 2) + if (state->nlookaheads < 2) return 0; for (i = 0; i < ntokens; i++) { int count = 0; int j; - for (j = m; j < n; j++) - if (BITISSET (LA (m), j)) + for (j = 0; j < state->nlookaheads; ++j) + if (bitset_test (LA[state->lookaheadsp + j], i)) count++; if (count >= 2) @@ -333,13 +315,13 @@ 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 (i), - count_rr_conflicts (i)), out); + fputs (conflict_report (count_sr_conflicts (states[i]), + count_rr_conflicts (states[i])), out); printed_sth = TRUE; } if (printed_sth) @@ -354,7 +336,7 @@ 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 @@ -368,8 +350,8 @@ conflicts_print (void) for (i = 0; i < nstates; i++) if (conflicts[i]) { - src_total += count_sr_conflicts (i); - rrc_total += count_rr_conflicts (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); @@ -410,147 +392,10 @@ conflicts_print (void) } -void -print_reductions (FILE *out, int state) -{ - int i; - int j; - int m; - int n; - shifts *shiftp; - errs *errp; - int nodefault = 0; - - for (i = 0; i < tokensetsize; i++) - shiftset[i] = 0; - - shiftp = state_table[state]->shifts; - 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)); - } - - errp = state_table[state]->errs; - if (errp) - for (i = 0; i < errp->nerrs; i++) - if (errp->errs[i]) - SETBIT (shiftset, errp->errs[i]); - - m = state_table[state]->lookaheads; - n = state_table[state + 1]->lookaheads; - - if (n - m == 1 && !nodefault) - { - int k; - int default_rule = LAruleno[m]; - - for (k = 0; k < tokensetsize; ++k) - lookaheadset[k] = LA (m)[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 (n - m >= 1) - { - int k; - - int cmax = 0; - int default_LA = -1; - int default_rule = 0; - - if (!nodefault) - for (i = m; i < n; i++) - { - int count = 0; - - for (k = 0; k < tokensetsize; ++k) - lookaheadset[k] = LA (i)[k] & ~shiftset[k]; - - for (j = 0; j < ntokens; j++) - if (BITISSET (lookaheadset, j)) - count++; - - if (count > cmax) - { - cmax = count; - default_LA = i; - default_rule = LAruleno[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 defaulted = 0; - int count = BITISSET (shiftset, i); - - for (j = m; j < n; j++) - { - if (BITISSET (LA (m), j)) - { - if (count == 0) - { - if (j != default_LA) - fprintf (out, - _(" %-4s\treduce using rule %d (%s)\n"), - tags[i], - LAruleno[j], - tags[rule_table[LAruleno[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[j], - tags[rule_table[LAruleno[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) { XFREE (conflicts); - XFREE (shiftset); - XFREE (lookaheadset); + bitset_free (shiftset); + bitset_free (lookaheadset); }