X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/4a713ec2e3f236999a20ab9c04004624ec63a557..983c5c2c2a4cc5b1dbd63236ad1215d2a113391e:/src/conflicts.c diff --git a/src/conflicts.c b/src/conflicts.c index 299327b0..fcfa735d 100644 --- a/src/conflicts.c +++ b/src/conflicts.c @@ -1,4 +1,5 @@ /* Find and resolve or report look-ahead conflicts for bison, + Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002 Free Software Foundation, Inc. @@ -20,17 +21,19 @@ 02111-1307, USA. */ #include "system.h" -#include "bitset.h" + +#include + +#include "LR0.h" #include "complain.h" -#include "getargs.h" -#include "symtab.h" +#include "conflicts.h" #include "files.h" +#include "getargs.h" #include "gram.h" -#include "state.h" #include "lalr.h" -#include "conflicts.h" #include "reader.h" -#include "LR0.h" +#include "state.h" +#include "symtab.h" /* -1 stands for not specified. */ int expected_conflicts = -1; @@ -42,19 +45,24 @@ static bitset lookaheadset; -enum conflict_resolution_e +enum conflict_resolution { shift_resolution, reduce_resolution, left_resolution, right_resolution, - nonassoc_resolution, + nonassoc_resolution }; +/*----------------------------------------------------------------. +| Explain how an SR conflict between TOKEN and RULE was resolved: | +| RESOLUTION. | +`----------------------------------------------------------------*/ + static inline void -log_resolution (int lookahead, int token, - enum conflict_resolution_e resolution) +log_resolution (rule *r, symbol_number token, + enum conflict_resolution resolution) { if (report_flag & report_solved_conflicts) { @@ -62,26 +70,26 @@ log_resolution (int lookahead, int token, switch (resolution) { case shift_resolution: - case left_resolution: + case right_resolution: obstack_fgrow2 (&solved_conflicts_obstack, _("\ Conflict between rule %d and token %s resolved as shift"), - LArule[lookahead]->number, + r->number, symbols[token]->tag); break; case reduce_resolution: - case right_resolution: + case left_resolution: obstack_fgrow2 (&solved_conflicts_obstack, _("\ Conflict between rule %d and token %s resolved as reduce"), - LArule[lookahead]->number, + 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"), - LArule[lookahead]->number, + r->number, symbols[token]->tag); break; } @@ -92,7 +100,7 @@ log_resolution (int lookahead, int token, case shift_resolution: obstack_fgrow2 (&solved_conflicts_obstack, " (%s < %s)", - LArule[lookahead]->prec->tag, + r->prec->tag, symbols[token]->tag); break; @@ -100,7 +108,7 @@ log_resolution (int lookahead, int token, obstack_fgrow2 (&solved_conflicts_obstack, " (%s < %s)", symbols[token]->tag, - LArule[lookahead]->prec->tag); + r->prec->tag); break; case left_resolution: @@ -132,15 +140,16 @@ log_resolution (int lookahead, int token, `------------------------------------------------------------------*/ static void -flush_shift (state_t *state, int token) +flush_shift (state *s, int token) { - shifts *shiftp = state->shifts; + transitions *trans = s->transitions; 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); + for (i = 0; i < trans->num; i++) + if (!TRANSITION_IS_DISABLED (trans, i) + && TRANSITION_SYMBOL (trans, i) == token) + TRANSITION_DISABLE (trans, i); } @@ -151,9 +160,9 @@ flush_shift (state_t *state, int token) `-------------------------------------------------------------------*/ static void -flush_reduce (int lookahead, int token) +flush_reduce (bitset lookaheads, int token) { - bitset_reset (LA[lookahead], token); + bitset_reset (lookaheads, token); } @@ -162,19 +171,25 @@ 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. | +| | +| ERRORS can be used to store discovered explicit errors. | `------------------------------------------------------------------*/ static void -resolve_sr_conflict (state_t *state, int lookahead) +resolve_sr_conflict (state *s, int ruleno, symbol **errors) { - int i; - /* find the rule to reduce by to get precedence of reduction */ - int redprec = LArule[lookahead]->prec->prec; - errs *errp = errs_new (ntokens + 1); - errp->nerrs = 0; + 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 lookaheads = reds->lookaheads[ruleno]; + int nerrs = 0; for (i = 0; i < ntokens; i++) - if (bitset_test (LA[lookahead], i) + if (bitset_test (lookaheads, i) && bitset_test (lookaheadset, i) && symbols[i]->prec) { @@ -183,13 +198,13 @@ resolve_sr_conflict (state_t *state, int lookahead) The precedence of shifting is that of token i. */ if (symbols[i]->prec < redprec) { - log_resolution (lookahead, i, reduce_resolution); - flush_shift (state, i); + log_resolution (redrule, i, reduce_resolution); + flush_shift (s, i); } else if (symbols[i]->prec > redprec) { - log_resolution (lookahead, i, shift_resolution); - flush_reduce (lookahead, i); + log_resolution (redrule, i, shift_resolution); + flush_reduce (lookaheads, i); } else /* Matching precedence levels. @@ -200,89 +215,113 @@ resolve_sr_conflict (state_t *state, int lookahead) switch (symbols[i]->assoc) { case right_assoc: - log_resolution (lookahead, i, right_resolution); - flush_reduce (lookahead, i); + log_resolution (redrule, i, right_resolution); + flush_reduce (lookaheads, i); break; case left_assoc: - log_resolution (lookahead, i, left_resolution); - flush_shift (state, i); + log_resolution (redrule, i, left_resolution); + flush_shift (s, i); break; case non_assoc: - log_resolution (lookahead, i, nonassoc_resolution); - flush_shift (state, i); - flush_reduce (lookahead, i); + log_resolution (redrule, i, nonassoc_resolution); + flush_shift (s, i); + flush_reduce (lookaheads, i); /* Record an explicit error for this token. */ - errp->errs[errp->nerrs++] = i; + errors[nerrs++] = symbols[i]; break; + + case undef_assoc: + abort (); } } /* Some tokens have been explicitly made errors. Allocate a permanent errs structure for this state, to record them. */ - state->errs = errs_dup (errp); - free (errp); + state_errs_set (s, nerrs, errors); if (obstack_object_size (&solved_conflicts_obstack)) { obstack_1grow (&solved_conflicts_obstack, '\0'); - state->solved_conflicts = obstack_finish (&solved_conflicts_obstack); + s->solved_conflicts = obstack_finish (&solved_conflicts_obstack); } } +/*-------------------------------------------------------------------. +| 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 | +| lookaheads on which S raises a syntax error (%nonassoc). | +`-------------------------------------------------------------------*/ + static void -set_conflicts (state_t *state) +set_conflicts (state *s, symbol **errors) { int i; - shifts *shiftp; + transitions *trans = s->transitions; + reductions *reds = s->reductions; - if (state->consistent) + if (s->consistent) return; bitset_zero (lookaheadset); - shiftp = state->shifts; - for (i = 0; i < shiftp->nshifts && SHIFT_IS_SHIFT (shiftp, i); i++) - if (!SHIFT_IS_DISABLED (shiftp, i)) - bitset_set (lookaheadset, SHIFT_SYMBOL (shiftp, i)); + FOR_EACH_SHIFT (trans, i) + bitset_set (lookaheadset, TRANSITION_SYMBOL (trans, 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 = 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)) + precedence. */ + for (i = 0; i < reds->num; ++i) + if (reds->rules[i]->prec && reds->rules[i]->prec->prec + && !bitset_disjoint_p (reds->lookaheads[i], lookaheadset)) { - resolve_sr_conflict (state, state->lookaheadsp + i); + resolve_sr_conflict (s, i, errors); 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 (i = 0; i < reds->num; ++i) { - if (!bitset_disjoint_p (LA[state->lookaheadsp + i], lookaheadset)) - conflicts[state->number] = 1; + if (!bitset_disjoint_p (reds->lookaheads[i], lookaheadset)) + conflicts[s->number] = 1; - bitset_or (lookaheadset, lookaheadset, LA[state->lookaheadsp + i]); + bitset_or (lookaheadset, lookaheadset, reds->lookaheads[i]); } } + +/*----------------------------------------------------------------. +| Solve all the S/R conflicts using the precedence/associativity, | +| and flag as inconsistent the states that still have conflicts. | +`----------------------------------------------------------------*/ + void conflicts_solve (void) { - size_t i; + state_number i; + /* List of lookaheads on which we explicitly raise a syntax error. */ + symbol **errors = MALLOC (errors, ntokens + 1); - conflicts = XCALLOC (char, nstates); + CALLOC (conflicts, nstates); 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 (states[i]); + { + set_conflicts (states[i], errors); + + /* For uniformity of the code, make sure all the states have a valid + `errs' member. */ + if (!states[i]->errs) + states[i]->errs = errs_new (0, 0); + } + + free (errors); } @@ -291,24 +330,24 @@ conflicts_solve (void) `---------------------------------------------*/ static int -count_sr_conflicts (state_t *state) +count_sr_conflicts (state *s) { int i; int src_count = 0; - shifts *shiftp = state->shifts; + transitions *trans = s->transitions; + reductions *reds = s->reductions; - if (!shiftp) + if (!trans) return 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)) - bitset_set (shiftset, SHIFT_SYMBOL (shiftp, i)); + FOR_EACH_SHIFT (trans, i) + bitset_set (shiftset, TRANSITION_SYMBOL (trans, i)); - for (i = 0; i < state->nlookaheads; ++i) - bitset_or (lookaheadset, lookaheadset, LA[state->lookaheadsp + i]); + for (i = 0; i < reds->num; ++i) + bitset_or (lookaheadset, lookaheadset, reds->lookaheads[i]); bitset_and (lookaheadset, lookaheadset, shiftset); @@ -318,34 +357,36 @@ count_sr_conflicts (state_t *state) } -/*----------------------------------------------. -| Count the number of reduce/reduce conflicts. | -`----------------------------------------------*/ +/*----------------------------------------------------------------. +| Count the number of reduce/reduce conflicts. If ONE_PER_TOKEN, | +| count one conflict for each token that has any reduce/reduce | +| conflicts. Otherwise, count one conflict for each pair of | +| conflicting reductions. | ++`----------------------------------------------------------------*/ static int -count_rr_conflicts (state_t *state) +count_rr_conflicts (state *s, int one_per_token) { int i; + reductions *reds = s->reductions; int rrc_count = 0; - if (state->nlookaheads < 2) - return 0; - for (i = 0; i < ntokens; i++) { int count = 0; int j; - for (j = 0; j < state->nlookaheads; ++j) - if (bitset_test (LA[state->lookaheadsp + j], i)) + for (j = 0; j < reds->num; ++j) + if (bitset_test (reds->lookaheads[j], i)) count++; if (count >= 2) - rrc_count++; + rrc_count += one_per_token ? 1 : count-1; } return rrc_count; } + /*--------------------------------------------------------------. | Return a human readable string which reports shift/reduce and | | reduce/reduce conflict numbers (SRC_NUM, RRC_NUM). | @@ -377,14 +418,32 @@ conflict_report (int src_num, int rrc_num) cp += strlen (cp); } - *cp++ = '.'; - *cp++ = '\n'; *cp++ = '\0'; return res; } +/*----------------------------------------------------------------. +| Same as above, but report the number of conflicts a` la POSIX. | +`----------------------------------------------------------------*/ + +static void +conflict_report_yacc (int src_num, int rrc_num) +{ + /* If invoked with `--yacc', use the output format specified by + POSIX. */ + fprintf (stderr, _("conflicts: ")); + if (src_num > 0) + fprintf (stderr, _(" %d shift/reduce"), src_num); + if (src_num > 0 && rrc_num > 0) + fprintf (stderr, ","); + if (rrc_num > 0) + fprintf (stderr, _(" %d reduce/reduce"), rrc_num); + putc ('\n', stderr); +} + + /*-----------------------------------------------------------. | Output the detailed description of states with conflicts. | `-----------------------------------------------------------*/ @@ -392,18 +451,46 @@ conflict_report (int src_num, int rrc_num) void conflicts_output (FILE *out) { - bool printed_sth = FALSE; - size_t i; + bool printed_sth = false; + state_number i; + for (i = 0; i < nstates; i++) + { + state *s = states[i]; + if (conflicts[i]) + { + fprintf (out, _("State %d contains "), i); + fprintf (out, "%s.\n", + conflict_report (count_sr_conflicts (s), + count_rr_conflicts (s, true))); + printed_sth = true; + } + } + if (printed_sth) + fputs ("\n\n", 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 lookahead as one | +| conflict. | +`--------------------------------------------------------*/ + +int +conflicts_total_count (void) +{ + state_number i; + int count; + + /* Conflicts by state. */ + count = 0; for (i = 0; i < nstates; i++) if (conflicts[i]) { - fprintf (out, _("State %d contains "), i); - fputs (conflict_report (count_sr_conflicts (states[i]), - count_rr_conflicts (states[i])), out); - printed_sth = TRUE; + count += count_sr_conflicts (states[i]); + count += count_rr_conflicts (states[i], false); } - if (printed_sth) - fputs ("\n\n", out); + return count; } @@ -414,8 +501,6 @@ conflicts_output (FILE *out) void conflicts_print (void) { - 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 case we want equality. */ @@ -425,12 +510,16 @@ conflicts_print (void) int rrc_total = 0; /* Conflicts by state. */ - for (i = 0; i < nstates; i++) - if (conflicts[i]) - { - src_total += count_sr_conflicts (states[i]); - rrc_total += count_rr_conflicts (states[i]); - } + { + state_number i; + + for (i = 0; i < nstates; i++) + if (conflicts[i]) + { + src_total += count_sr_conflicts (states[i]); + rrc_total += count_rr_conflicts (states[i], true); + } + } src_ok = src_total == (expected_conflicts == -1 ? 0 : expected_conflicts); @@ -441,32 +530,15 @@ conflicts_print (void) /* Report the total number of conflicts on STDERR. */ if (yacc_flag) - { - /* If invoked with `--yacc', use the output format specified by - POSIX. */ - fprintf (stderr, _("conflicts: ")); - if (src_total > 0) - fprintf (stderr, _(" %d shift/reduce"), src_total); - if (src_total > 0 && rrc_total > 0) - fprintf (stderr, ","); - if (rrc_total > 0) - fprintf (stderr, _(" %d reduce/reduce"), rrc_total); - putc ('\n', stderr); - } + conflict_report_yacc (src_total, rrc_total); else - { - fprintf (stderr, _("%s contains "), infile); - fputs (conflict_report (src_total, rrc_total), stderr); - } + warn ("%s", conflict_report (src_total, rrc_total)); if (expected_conflicts != -1 && !src_ok) - { - complain_message_count++; - fprintf (stderr, ngettext ("expected %d shift/reduce conflict\n", - "expected %d shift/reduce conflicts\n", - expected_conflicts), - expected_conflicts); - } + complain (ngettext ("expected %d shift/reduce conflict", + "expected %d shift/reduce conflicts", + expected_conflicts), + expected_conflicts); }