X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/035aa4a0bbf1847843c48312d892f79599ba7d8a..c1d19e10c32844d17122b473840752003521d21b:/src/conflicts.c diff --git a/src/conflicts.c b/src/conflicts.c index 374c4010..7bb3e08e 100644 --- a/src/conflicts.c +++ b/src/conflicts.c @@ -1,6 +1,6 @@ -/* 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 + Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -20,6 +20,7 @@ Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ +#include #include "system.h" #include @@ -39,10 +40,10 @@ int expected_sr_conflicts = -1; int expected_rr_conflicts = -1; static char *conflicts; -struct obstack solved_conflicts_obstack; +static struct obstack solved_conflicts_obstack; static bitset shift_set; -static bitset look_ahead_set; +static bitset lookahead_set; @@ -146,7 +147,7 @@ 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) @@ -156,14 +157,14 @@ 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 | +| specified lookahead. Used when we resolve a shift-reduce conflict | | in favor of the shift. | `--------------------------------------------------------------------*/ 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); } @@ -173,7 +174,7 @@ 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. | `------------------------------------------------------------------*/ @@ -186,12 +187,12 @@ resolve_sr_conflict (state *s, int ruleno, symbol **errors) /* 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]; + bitset lookahead_tokens = reds->lookahead_tokens[ruleno]; int nerrs = 0; 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 @@ -205,7 +206,7 @@ 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. @@ -215,9 +216,12 @@ resolve_sr_conflict (state *s, int ruleno, symbol **errors) switch (symbols[i]->assoc) { + default: + abort (); + case right_assoc: log_resolution (redrule, i, right_resolution); - flush_reduce (look_ahead_tokens, i); + flush_reduce (lookahead_tokens, i); break; case left_assoc: @@ -228,13 +232,10 @@ 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]; break; - - case undef_assoc: - abort (); } } @@ -257,7 +258,7 @@ 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 @@ -270,27 +271,27 @@ set_conflicts (state *s, symbol **errors) 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)) + && !bitset_disjoint_p (reds->lookahead_tokens[i], lookahead_set)) resolve_sr_conflict (s, i, errors); - /* 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]); } } @@ -304,12 +305,12 @@ 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); for (i = 0; i < nstates; i++) @@ -341,18 +342,18 @@ 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; } @@ -377,7 +378,7 @@ 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) @@ -432,7 +433,7 @@ 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. | `--------------------------------------------------------*/ @@ -529,6 +530,6 @@ conflicts_free (void) { free (conflicts); bitset_free (shift_set); - bitset_free (look_ahead_set); + bitset_free (lookahead_set); obstack_free (&solved_conflicts_obstack, NULL); }