X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/8b752b00fdaaa3802e4ab05a468f6cda4a9fa500..500bbfcd816776d0ddbf3555fedd41b529c405b3:/src/lalr.c?ds=sidebyside diff --git a/src/lalr.c b/src/lalr.c index d735921a..a549e5b4 100644 --- a/src/lalr.c +++ b/src/lalr.c @@ -32,7 +32,6 @@ #include "symtab.h" #include "gram.h" #include "reader.h" -#include "types.h" #include "LR0.h" #include "complain.h" #include "lalr.h" @@ -40,56 +39,46 @@ #include "derives.h" #include "getargs.h" -rule_t **LArule = NULL; -bitsetv LA = NULL; -size_t nLA; - -static int ngotos; -short *goto_map = NULL; +goto_number_t *goto_map = NULL; +static goto_number_t ngotos = 0; state_number_t *from_state = NULL; state_number_t *to_state = NULL; -/* And for the famous F variable, which name is so descriptive that a - comment is hardly needed. . */ -static bitsetv F = NULL; +/* Linked list of goto numbers. */ +typedef struct goto_list_s +{ + struct goto_list_s *next; + goto_number_t value; +} goto_list_t; -static short **includes; -static shorts **lookback; +/* LA is a LR by NTOKENS matrix of bits. LA[l, i] is 1 if the rule + LArule[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. */ +static bitsetv LA = NULL; +size_t nLA; -static void -initialize_LA (void) -{ - state_number_t i; - int j; - rule_t **np; +/* And for the famous F variable, which name is so descriptive that a + comment is hardly needed. . */ +static bitsetv F = NULL; - /* Avoid having to special case 0. */ - if (!nLA) - nLA = 1; +static goto_number_t **includes; +static goto_list_t **lookback; - LA = bitsetv_create (nLA, ntokens, BITSET_FIXED); - LArule = XCALLOC (rule_t *, nLA); - lookback = XCALLOC (shorts *, nLA); - np = LArule; - for (i = 0; i < nstates; i++) - if (!states[i]->consistent) - for (j = 0; j < states[i]->reductions->num; j++) - *np++ = &rules[states[i]->reductions->rules[j]]; -} static void set_goto_map (void) { state_number_t state; - short *temp_map; + goto_number_t *temp_map; - goto_map = XCALLOC (short, nvars + 1) - ntokens; - temp_map = XCALLOC (short, nvars + 1) - ntokens; + goto_map = XCALLOC (goto_number_t, nvars + 1) - ntokens; + temp_map = XCALLOC (goto_number_t, nvars + 1) - ntokens; ngotos = 0; for (state = 0; state < nstates; ++state) @@ -98,9 +87,8 @@ set_goto_map (void) int i; for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i) { - if (ngotos == SHRT_MAX) - fatal (_("too many gotos (max %d)"), SHRT_MAX); - + if (ngotos >= GOTO_NUMBER_MAX) + abort (); ngotos++; goto_map[TRANSITION_SYMBOL (sp, i)]++; } @@ -133,7 +121,7 @@ set_goto_map (void) { int k = temp_map[TRANSITION_SYMBOL (sp, i)]++; from_state[k] = state; - to_state[k] = sp->states[i]; + to_state[k] = sp->states[i]->number; } } @@ -157,8 +145,10 @@ map_goto (state_number_t state, symbol_number_t symbol) low = goto_map[symbol]; high = goto_map[symbol + 1] - 1; - while (low <= high) + for (;;) { + if (high < low) + abort (); middle = (low + high) / 2; s = from_state[middle]; if (s == state) @@ -168,18 +158,14 @@ map_goto (state_number_t state, symbol_number_t symbol) else high = middle - 1; } - - assert (0); - /* NOTREACHED */ - return 0; } static void initialize_F (void) { - short **reads = XCALLOC (short *, ngotos); - short *edge = XCALLOC (short, ngotos + 1); + goto_number_t **reads = XCALLOC (goto_number_t *, ngotos); + goto_number_t *edge = XCALLOC (goto_number_t, ngotos + 1); int nedges = 0; int i; @@ -192,7 +178,7 @@ initialize_F (void) transitions_t *sp = states[stateno]->transitions; int j; - for (j = 0; j < sp->num && TRANSITION_IS_SHIFT (sp, j); j++) + FOR_EACH_SHIFT (sp, j) bitset_set (F[i], TRANSITION_SYMBOL (sp, j)); for (; j < sp->num; j++) @@ -204,7 +190,7 @@ initialize_F (void) if (nedges) { - reads[i] = XCALLOC (short, nedges + 1); + reads[i] = XCALLOC (goto_number_t, nedges + 1); memcpy (reads[i], edge, nedges * sizeof (edge[0])); reads[i][nedges] = -1; nedges = 0; @@ -222,21 +208,13 @@ initialize_F (void) static void -add_lookback_edge (state_t *state, rule_number_t ruleno, int gotono) +add_lookback_edge (state_t *state, rule_t *rule, int gotono) { - int i; - shorts *sp; - - for (i = 0; i < state->nlookaheads; ++i) - if (state->lookaheads_rule[i]->number == ruleno) - break; - - assert (state->lookaheads_rule[i]->number == ruleno); - - sp = XCALLOC (shorts, 1); - sp->next = lookback[(state->lookaheads - LA) + i]; + int r = state_reduction_find (state, rule); + goto_list_t *sp = XCALLOC (goto_list_t, 1); + sp->next = lookback[(state->reductions->lookaheads - LA) + r]; sp->value = gotono; - lookback[(state->lookaheads - LA) + i] = sp; + lookback[(state->reductions->lookaheads - LA) + r] = sp; } @@ -244,19 +222,19 @@ add_lookback_edge (state_t *state, rule_number_t ruleno, int gotono) static void build_relations (void) { - short *edge = XCALLOC (short, ngotos + 1); + goto_number_t *edge = XCALLOC (goto_number_t, ngotos + 1); state_number_t *states1 = XCALLOC (state_number_t, ritem_longest_rhs () + 1); int i; - includes = XCALLOC (short *, ngotos); + includes = XCALLOC (goto_number_t *, ngotos); for (i = 0; i < ngotos; i++) { int nedges = 0; symbol_number_t symbol1 = states[to_state[i]]->accessing_symbol; - rule_number_t *rulep; + rule_t **rulep; - for (rulep = derives[symbol1]; *rulep > 0; rulep++) + for (rulep = derives[symbol1]; *rulep; rulep++) { int done; int length = 1; @@ -264,7 +242,7 @@ build_relations (void) state_t *state = states[from_state[i]]; states1[0] = state->number; - for (rp = rules[*rulep].rhs; *rp >= 0; rp++) + for (rp = (*rulep)->rhs; *rp >= 0; rp++) { state = transitions_to (state->transitions, item_number_as_symbol_number (*rp)); @@ -295,7 +273,7 @@ build_relations (void) if (nedges) { int j; - includes[i] = XCALLOC (short, nedges + 1); + includes[i] = XCALLOC (goto_number_t, nedges + 1); for (j = 0; j < nedges; j++) includes[i][j] = edge[j]; includes[i][nedges] = -1; @@ -328,7 +306,7 @@ static void compute_lookaheads (void) { size_t i; - shorts *sp; + goto_list_t *sp; for (i = 0; i < nLA; i++) for (sp = lookback[i]; sp; sp = sp->next) @@ -336,74 +314,79 @@ compute_lookaheads (void) /* Free LOOKBACK. */ for (i = 0; i < nLA; i++) - LIST_FREE (shorts, lookback[i]); + LIST_FREE (goto_list_t, lookback[i]); XFREE (lookback); bitsetv_free (F); } -/*-------------------------------------------------------------. -| Count the number of lookaheads required for each state | -| (NLOOKAHEADS member). Compute the total number of LA, NLA. | -`-------------------------------------------------------------*/ +/*---------------------------------------------------------------. +| Count the number of lookaheads required for STATE (NLOOKAHEADS | +| member). | +`---------------------------------------------------------------*/ -static void -states_lookaheads_count (void) +static int +state_lookaheads_count (state_t *state) { - state_number_t i; - nLA = 0; - - /* Count */ - for (i = 0; i < nstates; i++) - { - int k; - int nlookaheads = 0; - reductions_t *rp = states[i]->reductions; - transitions_t *sp = states[i]->transitions; - - /* We need a lookahead either to distinguish different - reductions (i.e., there are two or more), or to distinguish a - reduction from a shift. Otherwise, it is straightforward, - and the state is `consistent'. */ - if (rp->num > 1 - || (rp->num == 1 && sp->num && TRANSITION_IS_SHIFT (sp, 0))) - nlookaheads += rp->num; - else - states[i]->consistent = 1; - - for (k = 0; k < sp->num; k++) - if (TRANSITION_IS_ERROR (sp, k)) - { - states[i]->consistent = 0; - break; - } + int k; + int nlookaheads = 0; + reductions_t *rp = state->reductions; + transitions_t *sp = state->transitions; + + /* We need a lookahead either to distinguish different + reductions (i.e., there are two or more), or to distinguish a + reduction from a shift. Otherwise, it is straightforward, + and the state is `consistent'. */ + if (rp->num > 1 + || (rp->num == 1 && sp->num && + !TRANSITION_IS_DISABLED (sp, 0) && TRANSITION_IS_SHIFT (sp, 0))) + nlookaheads += rp->num; + else + state->consistent = 1; + + for (k = 0; k < sp->num; k++) + if (!TRANSITION_IS_DISABLED (sp, k) && TRANSITION_IS_ERROR (sp, k)) + { + state->consistent = 0; + break; + } - states[i]->nlookaheads = nlookaheads; - nLA += nlookaheads; - } + return nlookaheads; } -/*--------------------------------------. -| Initializing the lookaheads members. | -`--------------------------------------*/ +/*----------------------------------------------. +| Compute LA, NLA, and the lookaheads members. | +`----------------------------------------------*/ static void -states_lookaheads_initialize (void) +initialize_LA (void) { state_number_t i; - bitsetv pLA = LA; - rule_t **pLArule = LArule; + bitsetv pLA; - /* Initialize the members LOOKAHEADS and LOOKAHEADS_RULE for each - state. */ + /* Compute the total number of reductions requiring a lookahead. */ + nLA = 0; + for (i = 0; i < nstates; i++) + nLA += state_lookaheads_count (states[i]); + /* Avoid having to special case 0. */ + if (!nLA) + nLA = 1; + + pLA = LA = bitsetv_create (nLA, ntokens, BITSET_FIXED); + lookback = XCALLOC (goto_list_t *, nLA); + + /* Initialize the members LOOKAHEADS for each state which reductions + require lookaheads. */ for (i = 0; i < nstates; i++) { - states[i]->lookaheads = pLA; - states[i]->lookaheads_rule = pLArule; - pLA += states[i]->nlookaheads; - pLArule += states[i]->nlookaheads; + int count = state_lookaheads_count (states[i]); + if (count) + { + states[i]->reductions->lookaheads = pLA; + pLA += count; + } } } @@ -420,18 +403,26 @@ lookaheads_print (FILE *out) fprintf (out, "Lookaheads: BEGIN\n"); for (i = 0; i < nstates; ++i) { + reductions_t *reds = states[i]->reductions; bitset_iterator iter; + int nlookaheads = 0; + + if (reds->lookaheads) + for (k = 0; k < reds->num; ++k) + if (reds->lookaheads[k]) + ++nlookaheads; fprintf (out, "State %d: %d lookaheads\n", - i, states[i]->nlookaheads); + i, nlookaheads); - for (j = 0; j < states[i]->nlookaheads; ++j) - BITSET_FOR_EACH (iter, states[i]->lookaheads[j], k, 0) - { - fprintf (out, " on %d (%s) -> rule %d\n", - k, symbols[k]->tag, - states[i]->lookaheads_rule[j]->number - 1); - }; + if (reds->lookaheads) + for (j = 0; j < reds->num; ++j) + BITSET_FOR_EACH (iter, reds->lookaheads[j], k, 0) + { + fprintf (out, " on %d (%s) -> rule %d\n", + k, symbols[k]->tag, + reds->rules[j]->number); + }; } fprintf (out, "Lookaheads: END\n"); } @@ -439,15 +430,23 @@ lookaheads_print (FILE *out) void lalr (void) { - states_lookaheads_count (); initialize_LA (); - states_lookaheads_initialize (); set_goto_map (); initialize_F (); build_relations (); compute_FOLLOWS (); compute_lookaheads (); - if (trace_flag) + if (trace_flag & trace_sets) lookaheads_print (stderr); } + + +void +lalr_free (void) +{ + state_number_t s; + for (s = 0; s < nstates; ++s) + states[s]->reductions->lookaheads = NULL; + bitsetv_free (LA); +}