From 9801d40c506b718971aed52c44975c7951bcb3bc Mon Sep 17 00:00:00 2001 From: Akim Demaille Date: Sat, 15 Jun 2002 18:24:08 +0000 Subject: [PATCH] * src/conflicts.c (log_resolution): Accept the rule involved in the sr conflicts instead of the lookahead number that points to that rule. (flush_reduce): Accept the current lookahead vector as argument, instead of the index in LA. (resolve_sr_conflict): Accept the current number of lookahead bitset to consider for the STATE, instead of the index in LA. (set_conflicts): Adjust. * src/lalr.c, src/lalr.h, src/state.h: Comment changes. --- ChangeLog | 13 +++++++++++++ src/conflicts.c | 51 ++++++++++++++++++++++++++++++--------------------- src/lalr.c | 4 ++-- src/lalr.h | 2 +- src/state.h | 14 +++++++------- 5 files changed, 53 insertions(+), 31 deletions(-) diff --git a/ChangeLog b/ChangeLog index ec64bd6..b61837f 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,18 @@ 2002-06-15 Akim Demaille + * src/conflicts.c (log_resolution): Accept the rule involved in + the sr conflicts instead of the lookahead number that points to + that rule. + (flush_reduce): Accept the current lookahead vector as argument, + instead of the index in LA. + (resolve_sr_conflict): Accept the current number of lookahead + bitset to consider for the STATE, instead of the index in LA. + (set_conflicts): Adjust. + * src/lalr.c, src/lalr.h, src/state.h: Comment changes. + + +2002-06-15 Akim Demaille + * src/state.h (state_t): Replace the `lookaheadsp' member, a short, with `lookaheads' (bitsetv), `lookaheads_rule' (rule_t**). Adjust all dependencies. diff --git a/src/conflicts.c b/src/conflicts.c index 2cf6ce2..e09b6d8 100644 --- a/src/conflicts.c +++ b/src/conflicts.c @@ -52,8 +52,13 @@ enum conflict_resolution_e }; +/*----------------------------------------------------------------. +| Explain how an SR conflict between TOKEN and RULE was resolved: | +| RESOLUTION. | +`----------------------------------------------------------------*/ + static inline void -log_resolution (int lookahead, int token, +log_resolution (rule_t *rule, int token, enum conflict_resolution_e resolution) { if (report_flag & report_solved_conflicts) @@ -66,7 +71,7 @@ log_resolution (int lookahead, int token, obstack_fgrow2 (&solved_conflicts_obstack, _("\ Conflict between rule %d and token %s resolved as shift"), - LArule[lookahead]->number, + rule->number, symbols[token]->tag); break; case reduce_resolution: @@ -74,14 +79,14 @@ log_resolution (int lookahead, int token, obstack_fgrow2 (&solved_conflicts_obstack, _("\ Conflict between rule %d and token %s resolved as reduce"), - LArule[lookahead]->number, + 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"), - LArule[lookahead]->number, + rule->number, symbols[token]->tag); break; } @@ -92,7 +97,7 @@ log_resolution (int lookahead, int token, case shift_resolution: obstack_fgrow2 (&solved_conflicts_obstack, " (%s < %s)", - LArule[lookahead]->prec->tag, + rule->prec->tag, symbols[token]->tag); break; @@ -100,7 +105,7 @@ log_resolution (int lookahead, int token, obstack_fgrow2 (&solved_conflicts_obstack, " (%s < %s)", symbols[token]->tag, - LArule[lookahead]->prec->tag); + rule->prec->tag); break; case left_resolution: @@ -151,9 +156,9 @@ 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 +167,23 @@ 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 = LArule[lookahead]->prec->prec; + /* 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 (bitset_test (LA[lookahead], i) + if (bitset_test (lookaheads, i) && bitset_test (lookaheadset, i) && symbols[i]->prec) { @@ -183,13 +192,13 @@ 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); + log_resolution (redrule, i, reduce_resolution); flush_shift (state, 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. @@ -200,19 +209,19 @@ 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); + log_resolution (redrule, i, left_resolution); flush_shift (state, i); break; case non_assoc: - log_resolution (lookahead, i, nonassoc_resolution); + 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. */ errp->errs[errp->nerrs++] = i; break; @@ -254,13 +263,13 @@ set_conflicts (state_t *state) /* 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 (state->lookaheads_rule[i]->prec && state->lookaheads_rule[i]->prec->prec && !bitset_disjoint_p (state->lookaheads[i], lookaheadset)) { - resolve_sr_conflict (state, (state->lookaheads - LA) + i); + resolve_sr_conflict (state, i); break; } diff --git a/src/lalr.c b/src/lalr.c index 6d7b34f..14a3e23 100644 --- a/src/lalr.c +++ b/src/lalr.c @@ -559,8 +559,8 @@ states_lookaheads_initialize (void) bitsetv pLA = LA; rule_t **pLArule = LArule; - /* Count the number of lookaheads required for each state - (NLOOKAHEADS member). */ + /* Initialize the members LOOKAHEADS and LOOKAHEADS_RULE for each + state. */ for (i = 0; i < nstates; i++) { states[i]->lookaheads = pLA; diff --git a/src/lalr.h b/src/lalr.h index 6093105..ab1c8ba 100644 --- a/src/lalr.h +++ b/src/lalr.h @@ -63,7 +63,7 @@ extern short *to_state; extern rule_t **LArule; -/* LA is a lr by ntokens matrix of bits. LA[l, i] is 1 if the rule +/* LA is a LR by NTOKENS matrix of bits. LA[l, i] is 1 if the rule LAruleno[l] is applicable in the appropriate state when the next token is symbol i. If LA[l, i] and LA[l, j] are both 1 for i != j, it is a conflict. */ diff --git a/src/state.h b/src/state.h index 7f578bd..239a367 100644 --- a/src/state.h +++ b/src/state.h @@ -30,19 +30,19 @@ state. These symbols at these items are the allowable inputs that can follow now. - A core represents one state. States are numbered in the number + A core represents one state. States are numbered in the NUMBER field. When generate_states is finished, the starting state is - state 0 and nstates is the number of states. (A transition to a - state whose state number is nstates indicates termination.) All - the cores are chained together and first_state points to the first - one (state 0). + state 0 and NSTATES is the number of states. (FIXME: This sentence + is no longer true: A transition to a state whose state number is + NSTATES indicates termination.) All the cores are chained together + and FIRST_STATE points to the first one (state 0). For each state there is a particular symbol which must have been the last thing accepted to reach that state. It is the - accessing_symbol of the core. + ACCESSING_SYMBOL of the core. Each core contains a vector of NITEMS items which are the indices - in the ritems vector of the items that are selected in this state. + in the RITEMS vector of the items that are selected in this state. The link field is used for chaining symbols that hash states by their itemsets. This is for recognizing equivalent states and -- 2.7.4