X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/7612000cb004ae5b8516e3a34a79ab32050d688e..c826013fb38c98861ef0fc5d4dc3fb3fb4f555be:/src/lalr.c?ds=sidebyside diff --git a/src/lalr.c b/src/lalr.c index 31ca44da..6f099a8b 100644 --- a/src/lalr.c +++ b/src/lalr.c @@ -1,770 +1,502 @@ -/* Compute look-ahead criteria for bison, - Copyright (C) 1984, 1986, 1989 Free Software Foundation, Inc. +/* Compute lookahead criteria for Bison. -This file is part of Bison, the GNU Compiler Compiler. + Copyright (C) 1984, 1986, 1989, 2000-2010 Free Software Foundation, + Inc. -Bison is free software; you can redistribute it and/or modify -it under the terms of the GNU General Public License as published by -the Free Software Foundation; either version 2, or (at your option) -any later version. + This file is part of Bison, the GNU Compiler Compiler. -Bison is distributed in the hope that it will be useful, -but WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -GNU General Public License for more details. + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. -You should have received a copy of the GNU General Public License -along with Bison; see the file COPYING. If not, write to -the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ -/* Compute how to make the finite state machine deterministic; - find which rules need lookahead in each state, and which lookahead tokens they accept. -lalr(), the entry point, builds these data structures: +/* Find which rules need lookahead in each state, and which lookahead + tokens they accept. */ -goto_map, from_state and to_state - record each shift transition which accepts a variable (a nonterminal). -ngotos is the number of such transitions. -from_state[t] is the state number which a transition leads from -and to_state[t] is the state number it leads to. -All the transitions that accept a particular variable are grouped together and -goto_map[i - ntokens] is the index in from_state and to_state of the first of them. - -consistent[s] is nonzero if no lookahead is needed to decide what to do in state s. - -LAruleno is a vector which records the rules that need lookahead in various states. -The elements of LAruleno that apply to state s are those from - lookaheads[s] through lookaheads[s+1]-1. -Each element of LAruleno is a rule number. - -If lr is the length of LAruleno, then a number from 0 to lr-1 -can specify both a rule and a state where the rule might be applied. - -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. -*/ - -#include +#include #include "system.h" -#include "machine.h" -#include "types.h" -#include "state.h" -#include "alloc.h" -#include "gram.h" - - -extern short **derives; -extern char *nullable; - - -int tokensetsize; -short *lookaheads; -short *LAruleno; -unsigned *LA; -short *accessing_symbol; -char *consistent; -core **state_table; -shifts **shift_table; -reductions **reduction_table; -short *goto_map; -short *from_state; -short *to_state; - -short **transpose(); -void set_state_table(); -void set_accessing_symbol(); -void set_shift_table(); -void set_reduction_table(); -void set_maxrhs(); -void initialize_LA(); -void set_goto_map(); -void initialize_F(); -void build_relations(); -void add_lookback_edge(); -void compute_FOLLOWS(); -void compute_lookaheads(); -void digraph(); -void traverse(); - -extern void toomany(); -extern void berror(); - -static int infinity; -static int maxrhs; -static int ngotos; -static unsigned *F; -static short **includes; -static shorts **lookback; -static short **R; -static short *INDEX; -static short *VERTICES; -static int top; - - -void -lalr() -{ - tokensetsize = WORDSIZE(ntokens); - - set_state_table(); - set_accessing_symbol(); - set_shift_table(); - set_reduction_table(); - set_maxrhs(); - initialize_LA(); - set_goto_map(); - initialize_F(); - build_relations(); - compute_FOLLOWS(); - compute_lookaheads(); -} - - -void -set_state_table() -{ - register core *sp; - - state_table = NEW2(nstates, core *); - - for (sp = first_state; sp; sp = sp->next) - state_table[sp->number] = sp; -} - - -void -set_accessing_symbol() -{ - register core *sp; - - accessing_symbol = NEW2(nstates, short); - - for (sp = first_state; sp; sp = sp->next) - accessing_symbol[sp->number] = sp->accessing_symbol; -} - - -void -set_shift_table() -{ - register shifts *sp; - - shift_table = NEW2(nstates, shifts *); - - for (sp = first_shift; sp; sp = sp->next) - shift_table[sp->number] = sp; -} - - -void -set_reduction_table() -{ - register reductions *rp; - - reduction_table = NEW2(nstates, reductions *); - - for (rp = first_reduction; rp; rp = rp->next) - reduction_table[rp->number] = rp; -} - - -void -set_maxrhs() -{ - register short *itemp; - register int length; - register int max; - - length = 0; - max = 0; - for (itemp = ritem; *itemp; itemp++) - { - if (*itemp > 0) - { - length++; - } - else - { - if (length > max) max = length; - length = 0; - } - } - - maxrhs = max; -} +#include +#include +#include -void -initialize_LA() +#include "LR0.h" +#include "complain.h" +#include "derives.h" +#include "getargs.h" +#include "gram.h" +#include "lalr.h" +#include "muscle-tab.h" +#include "nullable.h" +#include "reader.h" +#include "relation.h" +#include "symtab.h" + +goto_number *goto_map; +goto_number ngotos; +state_number *from_state; +state_number *to_state; +bitsetv goto_follows = NULL; + +/* Linked list of goto numbers. */ +typedef struct goto_list { - register int i; - register int j; - register int count; - register reductions *rp; - register shifts *sp; - register short *np; + struct goto_list *next; + goto_number value; +} goto_list; - consistent = NEW2(nstates, char); - lookaheads = NEW2(nstates + 1, short); - - count = 0; - for (i = 0; i < nstates; i++) - { - register int k; - lookaheads[i] = count; +/* LA is an NLA 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. */ - rp = reduction_table[i]; - sp = shift_table[i]; - if (rp && (rp->nreds > 1 - || (sp && ! ISVAR(accessing_symbol[sp->shifts[0]])))) - count += rp->nreds; - else - consistent[i] = 1; +static bitsetv LA = NULL; +size_t nLA; - if (sp) - for (k = 0; k < sp->nshifts; k++) - { - if (accessing_symbol[sp->shifts[k]] == error_token_number) - { - consistent[i] = 0; - break; - } - } - } - lookaheads[nstates] = count; +static goto_number **includes; +static goto_list **lookback; - if (count == 0) - { - LA = NEW2(1 * tokensetsize, unsigned); - LAruleno = NEW2(1, short); - lookback = NEW2(1, shorts *); - } - else - { - LA = NEW2(count * tokensetsize, unsigned); - LAruleno = NEW2(count, short); - lookback = NEW2(count, shorts *); - } - np = LAruleno; - for (i = 0; i < nstates; i++) - { - if (!consistent[i]) - { - if (rp = reduction_table[i]) - for (j = 0; j < rp->nreds; j++) - *np++ = rp->rules[j]; - } - } -} void -set_goto_map() +set_goto_map (void) { - register shifts *sp; - register int i; - register int symbol; - register int k; - register short *temp_map; - register int state2; - register int state1; + state_number s; + goto_number *temp_map; - goto_map = NEW2(nvars + 1, short) - ntokens; - temp_map = NEW2(nvars + 1, short) - ntokens; + goto_map = xcalloc (nvars + 1, sizeof *goto_map); + temp_map = xnmalloc (nvars + 1, sizeof *temp_map); ngotos = 0; - for (sp = first_shift; sp; sp = sp->next) + for (s = 0; s < nstates; ++s) { - for (i = sp->nshifts - 1; i >= 0; i--) + transitions *sp = states[s]->transitions; + int i; + for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i) { - symbol = accessing_symbol[sp->shifts[i]]; - - if (ISTOKEN(symbol)) break; + ngotos++; - if (ngotos == MAXSHORT) - toomany(_("gotos")); + /* Abort if (ngotos + 1) would overflow. */ + aver (ngotos != GOTO_NUMBER_MAXIMUM); - ngotos++; - goto_map[symbol]++; - } + goto_map[TRANSITION_SYMBOL (sp, i) - ntokens]++; + } } - k = 0; - for (i = ntokens; i < nsyms; i++) - { - temp_map[i] = k; - k += goto_map[i]; - } + { + goto_number k = 0; + int i; + for (i = ntokens; i < nsyms; i++) + { + temp_map[i - ntokens] = k; + k += goto_map[i - ntokens]; + } - for (i = ntokens; i < nsyms; i++) - goto_map[i] = temp_map[i]; + for (i = ntokens; i < nsyms; i++) + goto_map[i - ntokens] = temp_map[i - ntokens]; - goto_map[nsyms] = ngotos; - temp_map[nsyms] = ngotos; + goto_map[nsyms - ntokens] = ngotos; + temp_map[nsyms - ntokens] = ngotos; + } - from_state = NEW2(ngotos, short); - to_state = NEW2(ngotos, short); + from_state = xcalloc (ngotos, sizeof *from_state); + to_state = xcalloc (ngotos, sizeof *to_state); - for (sp = first_shift; sp; sp = sp->next) + for (s = 0; s < nstates; ++s) { - state1 = sp->number; - for (i = sp->nshifts - 1; i >= 0; i--) + transitions *sp = states[s]->transitions; + int i; + for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i) { - state2 = sp->shifts[i]; - symbol = accessing_symbol[state2]; - - if (ISTOKEN(symbol)) break; - - k = temp_map[symbol]++; - from_state[k] = state1; - to_state[k] = state2; + goto_number k = temp_map[TRANSITION_SYMBOL (sp, i) - ntokens]++; + from_state[k] = s; + to_state[k] = sp->states[i]->number; } } - FREE(temp_map + ntokens); + free (temp_map); } - -/* Map_goto maps a state/symbol pair into its numeric representation. */ - -int -map_goto(state, symbol) -int state; -int symbol; +goto_number +map_goto (state_number s0, symbol_number sym) { - register int high; - register int low; - register int middle; - register int s; + goto_number high; + goto_number low; + goto_number middle; + state_number s; - low = goto_map[symbol]; - high = goto_map[symbol + 1] - 1; + low = goto_map[sym - ntokens]; + high = goto_map[sym - ntokens + 1] - 1; - while (low <= high) + for (;;) { + aver (low <= high); middle = (low + high) / 2; s = from_state[middle]; - if (s == state) - return (middle); - else if (s < state) + if (s == s0) + return middle; + else if (s < s0) low = middle + 1; else high = middle - 1; } - - berror("map_goto"); -/* NOTREACHED */ - return 0; } -void -initialize_F() +static void +initialize_F (void) { - register int i; - register int j; - register int k; - register shifts *sp; - register short *edge; - register unsigned *rowp; - register short *rp; - register short **reads; - register int nedges; - register int stateno; - register int symbol; - register int nwords; - - nwords = ngotos * tokensetsize; - F = NEW2(nwords, unsigned); - - reads = NEW2(ngotos, short *); - edge = NEW2(ngotos + 1, short); - nedges = 0; - - rowp = F; - for (i = 0; i < ngotos; i++) - { - stateno = to_state[i]; - sp = shift_table[stateno]; + goto_number **reads = xnmalloc (ngotos, sizeof *reads); + goto_number *edge = xnmalloc (ngotos + 1, sizeof *edge); + goto_number nedges = 0; - if (sp) - { - k = sp->nshifts; + goto_number i; - for (j = 0; j < k; j++) - { - symbol = accessing_symbol[sp->shifts[j]]; - if (ISVAR(symbol)) - break; - SETBIT(rowp, symbol); - } + goto_follows = bitsetv_create (ngotos, ntokens, BITSET_FIXED); - for (; j < k; j++) - { - symbol = accessing_symbol[sp->shifts[j]]; - if (nullable[symbol]) - edge[nedges++] = map_goto(stateno, symbol); - } - - if (nedges) - { - reads[i] = rp = NEW2(nedges + 1, short); + for (i = 0; i < ngotos; i++) + { + state_number stateno = to_state[i]; + transitions *sp = states[stateno]->transitions; - for (j = 0; j < nedges; j++) - rp[j] = edge[j]; + int j; + FOR_EACH_SHIFT (sp, j) + bitset_set (goto_follows[i], TRANSITION_SYMBOL (sp, j)); - rp[nedges] = -1; - nedges = 0; - } + for (; j < sp->num; j++) + { + symbol_number sym = TRANSITION_SYMBOL (sp, j); + if (nullable[sym - ntokens]) + edge[nedges++] = map_goto (stateno, sym); } - rowp += tokensetsize; + if (nedges == 0) + reads[i] = NULL; + else + { + reads[i] = xnmalloc (nedges + 1, sizeof reads[i][0]); + memcpy (reads[i], edge, nedges * sizeof edge[0]); + reads[i][nedges] = END_NODE; + nedges = 0; + } } - digraph(reads); + relation_digraph (reads, ngotos, &goto_follows); for (i = 0; i < ngotos; i++) - { - if (reads[i]) - FREE(reads[i]); - } + free (reads[i]); - FREE(reads); - FREE(edge); + free (reads); + free (edge); } -void -build_relations() +static void +add_lookback_edge (state *s, rule *r, goto_number gotono) +{ + int ri = state_reduction_find (s, r); + goto_list *sp = xmalloc (sizeof *sp); + sp->next = lookback[(s->reductions->lookahead_tokens - LA) + ri]; + sp->value = gotono; + lookback[(s->reductions->lookahead_tokens - LA) + ri] = sp; +} + + + +static void +build_relations (void) { - register int i; - register int j; - register int k; - register short *rulep; - register short *rp; - register shifts *sp; - register int length; - register int nedges; - register int done; - register int state1; - register int stateno; - register int symbol1; - register int symbol2; - register short *shortp; - register short *edge; - register short *states; - register short **new_includes; - - includes = NEW2(ngotos, short *); - edge = NEW2(ngotos + 1, short); - states = NEW2(maxrhs + 1, short); + goto_number *edge = xnmalloc (ngotos + 1, sizeof *edge); + state_number *states1 = xnmalloc (ritem_longest_rhs () + 1, sizeof *states1); + goto_number i; + + includes = xnmalloc (ngotos, sizeof *includes); for (i = 0; i < ngotos; i++) { - nedges = 0; - state1 = from_state[i]; - symbol1 = accessing_symbol[to_state[i]]; + int nedges = 0; + symbol_number symbol1 = states[to_state[i]]->accessing_symbol; + rule **rulep; - for (rulep = derives[symbol1]; *rulep > 0; rulep++) + for (rulep = derives[symbol1 - ntokens]; *rulep; rulep++) { - length = 1; - states[0] = state1; - stateno = state1; + bool done; + int length = 1; + item_number const *rp; + state *s = states[from_state[i]]; + states1[0] = s->number; - for (rp = ritem + rrhs[*rulep]; *rp > 0; rp++) + for (rp = (*rulep)->rhs; ! item_number_is_rule_number (*rp); rp++) { - symbol2 = *rp; - sp = shift_table[stateno]; - k = sp->nshifts; - - for (j = 0; j < k; j++) - { - stateno = sp->shifts[j]; - if (accessing_symbol[stateno] == symbol2) break; - } - - states[length++] = stateno; + s = transitions_to (s->transitions, + item_number_as_symbol_number (*rp)); + states1[length++] = s->number; } - if (!consistent[stateno]) - add_lookback_edge(stateno, *rulep, i); + if (!s->consistent) + add_lookback_edge (s, *rulep, i); length--; - done = 0; + done = false; while (!done) { - done = 1; + done = true; + /* Each rhs ends in a rule number, and there is a + sentinel (ritem[-1]=0) before the first rhs, so it is safe to + decrement RP here. */ rp--; - /* JF added rp>=ritem && I hope to god its right! */ - if (rp>=ritem && ISVAR(*rp)) + if (ISVAR (*rp)) { - stateno = states[--length]; - edge[nedges++] = map_goto(stateno, *rp); - if (nullable[*rp]) done = 0; + /* Downcasting from item_number to symbol_number. */ + edge[nedges++] = map_goto (states1[--length], + item_number_as_symbol_number (*rp)); + if (nullable[*rp - ntokens]) + done = false; } } } - if (nedges) + if (nedges == 0) + includes[i] = NULL; + else { - includes[i] = shortp = NEW2(nedges + 1, short); + int j; + includes[i] = xnmalloc (nedges + 1, sizeof includes[i][0]); for (j = 0; j < nedges; j++) - shortp[j] = edge[j]; - shortp[nedges] = -1; + includes[i][j] = edge[j]; + includes[i][nedges] = END_NODE; } } - new_includes = transpose(includes, ngotos); - - for (i = 0; i < ngotos; i++) - if (includes[i]) - FREE(includes[i]); - - FREE(includes); + free (edge); + free (states1); - includes = new_includes; - - FREE(edge); - FREE(states); + relation_transpose (&includes, ngotos); } -void -add_lookback_edge(stateno, ruleno, gotono) -int stateno; -int ruleno; -int gotono; + +static void +compute_FOLLOWS (void) { - register int i; - register int k; - register int found; - register shorts *sp; - - i = lookaheads[stateno]; - k = lookaheads[stateno + 1]; - found = 0; - while (!found && i < k) - { - if (LAruleno[i] == ruleno) - found = 1; - else - i++; - } + goto_number i; - if (found == 0) - berror("add_lookback_edge"); + relation_digraph (includes, ngotos, &goto_follows); - sp = NEW(shorts); - sp->next = lookback[i]; - sp->value = gotono; - lookback[i] = sp; -} + for (i = 0; i < ngotos; i++) + free (includes[i]); + free (includes); +} -short ** -transpose(R_arg, n) -short **R_arg; -int n; +static void +compute_lookahead_tokens (void) { - register short **new_R; - register short **temp_R; - register short *nedges; - register short *sp; - register int i; - register int k; - - nedges = NEW2(n, short); + size_t i; + goto_list *sp; - for (i = 0; i < n; i++) - { - sp = R_arg[i]; - if (sp) - { - while (*sp >= 0) - nedges[*sp++]++; - } - } + for (i = 0; i < nLA; i++) + for (sp = lookback[i]; sp; sp = sp->next) + bitset_or (LA[i], LA[i], goto_follows[sp->value]); - new_R = NEW2(n, short *); - temp_R = NEW2(n, short *); + /* Free LOOKBACK. */ + for (i = 0; i < nLA; i++) + LIST_FREE (goto_list, lookback[i]); - for (i = 0; i < n; i++) - { - k = nedges[i]; - if (k > 0) - { - sp = NEW2(k + 1, short); - new_R[i] = sp; - temp_R[i] = sp; - sp[k] = -1; - } - } + free (lookback); +} - FREE(nedges); - for (i = 0; i < n; i++) - { - sp = R_arg[i]; - if (sp) - { - while (*sp >= 0) - *temp_R[*sp++]++ = i; - } - } +/*----------------------------------------------------. +| Count the number of lookahead tokens required for S | +| (N_LOOKAHEAD_TOKENS member). | +`----------------------------------------------------*/ - FREE(temp_R); +static int +state_lookahead_tokens_count (state *s, bool default_reduction_only_for_accept) +{ + int n_lookahead_tokens = 0; + reductions *rp = s->reductions; + transitions *sp = s->transitions; + + /* Transitions are only disabled during conflict resolution, and that + hasn't happened yet, so there should be no need to check that + transition 0 hasn't been disabled before checking if it is a shift. + However, this check was performed at one time, so we leave it as an + aver. */ + aver (sp->num == 0 || !TRANSITION_IS_DISABLED (sp, 0)); + + /* 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'. However, do not treat a state with any reductions as + consistent unless it is the accepting state (because there is never + a lookahead token that makes sense there, and so no lookahead token + should be read) if the user has otherwise disabled default + reductions. */ + if (rp->num > 1 + || (rp->num == 1 && sp->num && TRANSITION_IS_SHIFT (sp, 0)) + || (rp->num == 1 && rp->rules[0]->number != 0 + && default_reduction_only_for_accept)) + n_lookahead_tokens += rp->num; + else + s->consistent = 1; - return (new_R); + return n_lookahead_tokens; } +/*----------------------------------------------------. +| Compute LA, NLA, and the lookahead_tokens members. | +`----------------------------------------------------*/ + void -compute_FOLLOWS() +initialize_LA (void) { - register int i; + state_number i; + bitsetv pLA; + bool default_reduction_only_for_accept; + { + char *default_reductions = + muscle_percent_define_get ("lr.default-reductions"); + default_reduction_only_for_accept = + 0 == strcmp (default_reductions, "accepting"); + free (default_reductions); + } + + /* Compute the total number of reductions requiring a lookahead. */ + nLA = 0; + for (i = 0; i < nstates; i++) + nLA += + state_lookahead_tokens_count (states[i], + default_reduction_only_for_accept); + /* Avoid having to special case 0. */ + if (!nLA) + nLA = 1; - digraph(includes); + pLA = LA = bitsetv_create (nLA, ntokens, BITSET_FIXED); - for (i = 0; i < ngotos; i++) + /* Initialize the members LOOKAHEAD_TOKENS for each state whose reductions + require lookahead tokens. */ + for (i = 0; i < nstates; i++) { - if (includes[i]) FREE(includes[i]); + int count = + state_lookahead_tokens_count (states[i], + default_reduction_only_for_accept); + if (count) + { + states[i]->reductions->lookahead_tokens = pLA; + pLA += count; + } } - - FREE(includes); } -void -compute_lookaheads() +/*---------------------------------------------. +| Output the lookahead tokens for each state. | +`---------------------------------------------*/ + +static void +lookahead_tokens_print (FILE *out) { - register int i; - register int n; - register unsigned *fp1; - register unsigned *fp2; - register unsigned *fp3; - register shorts *sp; - register unsigned *rowp; -/* register short *rulep; JF unused */ -/* register int count; JF unused */ - register shorts *sptmp;/* JF */ - - rowp = LA; - n = lookaheads[nstates]; - for (i = 0; i < n; i++) + state_number i; + int j, k; + fprintf (out, "Lookahead tokens: BEGIN\n"); + for (i = 0; i < nstates; ++i) { - fp3 = rowp + tokensetsize; - for (sp = lookback[i]; sp; sp = sp->next) - { - fp1 = rowp; - fp2 = F + tokensetsize * sp->value; - while (fp1 < fp3) - *fp1++ |= *fp2++; - } + reductions *reds = states[i]->reductions; + bitset_iterator iter; + int n_lookahead_tokens = 0; - rowp = fp3; - } + if (reds->lookahead_tokens) + for (k = 0; k < reds->num; ++k) + if (reds->lookahead_tokens[k]) + ++n_lookahead_tokens; - for (i = 0; i < n; i++) - {/* JF removed ref to freed storage */ - for (sp = lookback[i]; sp; sp = sptmp) { - sptmp=sp->next; - FREE(sp); - } - } + fprintf (out, "State %d: %d lookahead tokens\n", + i, n_lookahead_tokens); - FREE(lookback); - FREE(F); + if (reds->lookahead_tokens) + for (j = 0; j < reds->num; ++j) + BITSET_FOR_EACH (iter, reds->lookahead_tokens[j], k, 0) + { + fprintf (out, " on %d (%s) -> rule %d\n", + k, symbols[k]->tag, + reds->rules[j]->number); + }; + } + fprintf (out, "Lookahead tokens: END\n"); } - void -digraph(relation) -short **relation; +lalr (void) { - register int i; - - infinity = ngotos + 2; - INDEX = NEW2(ngotos + 1, short); - VERTICES = NEW2(ngotos + 1, short); - top = 0; - - R = relation; - - for (i = 0; i < ngotos; i++) - INDEX[i] = 0; - - for (i = 0; i < ngotos; i++) - { - if (INDEX[i] == 0 && R[i]) - traverse(i); - } - - FREE(INDEX); - FREE(VERTICES); + initialize_LA (); + set_goto_map (); + initialize_F (); + lookback = xcalloc (nLA, sizeof *lookback); + build_relations (); + compute_FOLLOWS (); + compute_lookahead_tokens (); + + if (trace_flag & trace_sets) + lookahead_tokens_print (stderr); } void -traverse(i) -register int i; +lalr_update_state_numbers (state_number old_to_new[], state_number nstates_old) { - register unsigned *fp1; - register unsigned *fp2; - register unsigned *fp3; - register int j; - register short *rp; - - int height; - unsigned *base; - - VERTICES[++top] = i; - INDEX[i] = height = top; - - base = F + i * tokensetsize; - fp3 = base + tokensetsize; - - rp = R[i]; - if (rp) + goto_number ngotos_reachable = 0; + symbol_number nonterminal = 0; + aver (nsyms == nvars + ntokens); + { + goto_number i; + for (i = 0; i < ngotos; ++i) + { + while (i == goto_map[nonterminal]) + goto_map[nonterminal++] = ngotos_reachable; + /* If old_to_new[from_state[i]] = nstates_old, remove this goto + entry. */ + if (old_to_new[from_state[i]] != nstates_old) + { + /* from_state[i] is not removed, so it and thus to_state[i] are + reachable, so to_state[i] != nstates_old. */ + aver (old_to_new[to_state[i]] != nstates_old); + from_state[ngotos_reachable] = old_to_new[from_state[i]]; + to_state[ngotos_reachable] = old_to_new[to_state[i]]; + ++ngotos_reachable; + } + } + } + while (nonterminal <= nvars) { - while ((j = *rp++) >= 0) - { - if (INDEX[j] == 0) - traverse(j); - - if (INDEX[i] > INDEX[j]) - INDEX[i] = INDEX[j]; - - fp1 = base; - fp2 = F + j * tokensetsize; - - while (fp1 < fp3) - *fp1++ |= *fp2++; - } + aver (ngotos == goto_map[nonterminal]); + goto_map[nonterminal++] = ngotos_reachable; } + ngotos = ngotos_reachable; +} - if (INDEX[i] == height) - { - for (;;) - { - j = VERTICES[top--]; - INDEX[j] = infinity; - - if (i == j) - break; - - fp1 = base; - fp2 = F + j * tokensetsize; - while (fp1 < fp3) - *fp2++ = *fp1++; - } - } +void +lalr_free (void) +{ + state_number s; + for (s = 0; s < nstates; ++s) + states[s]->reductions->lookahead_tokens = NULL; + bitsetv_free (LA); }