X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/f67d13aa6c0869bae958cd2a8b795468464ecf13..dac3c910059dc8a137355d5c58dfd3a9ad6fbbe1:/src/lalr.c diff --git a/src/lalr.c b/src/lalr.c index eb226f44..be178b8d 100644 --- a/src/lalr.c +++ b/src/lalr.c @@ -33,24 +33,19 @@ #include "derives.h" #include "getargs.h" -/* All the decorated states, indexed by the state number. Warning: - there is a state_TABLE in LR0.c, but it is different and static. - */ -state_t *state_table = NULL; +/* All the decorated states, indexed by the state number. */ +state_t **state_table = NULL; int tokensetsize; short *LAruleno; unsigned *LA; +size_t nLA; +static int ngotos; short *goto_map; short *from_state; short *to_state; -extern void berror PARAMS ((const char *)); - -static int infinity; -static int ngotos; - /* And for the famous F variable, which name is so descriptive that a comment is hardly needed. . */ static unsigned *F = NULL; @@ -58,11 +53,20 @@ static unsigned *F = NULL; static short **includes; static shorts **lookback; + + +/*---------------------------------------------------------------. +| digraph & traverse. | +| | +| The following variables are used as common storage between the | +| two. | +`---------------------------------------------------------------*/ + static short **R; static short *INDEX; static short *VERTICES; static int top; - +static int infinity; static void traverse (int i) @@ -98,7 +102,7 @@ traverse (int i) break; for (k = 0; k < size; ++k) - F (i)[k] = F (j)[k]; + F (j)[k] = F (i)[k]; } } @@ -127,74 +131,6 @@ digraph (short **relation) } -/*--------------------. -| Build STATE_TABLE. | -`--------------------*/ - -static void -set_state_table (void) -{ - /* NSTATES + 1 because lookahead for the pseudo state number NSTATES - might be used (see conflicts.c). It is too opaque for me to - provide a probably less hacky implementation. --akim */ - state_table = XCALLOC (state_t, nstates + 1); - - { - core *sp; - for (sp = first_state; sp; sp = sp->next) - { - state_table[sp->number].state = sp; - state_table[sp->number].accessing_symbol = sp->accessing_symbol; - } - } - - { - shifts *sp; - for (sp = first_shift; sp; sp = sp->next) - state_table[sp->number].shift_table = sp; - } - - { - reductions *rp; - for (rp = first_reduction; rp; rp = rp->next) - state_table[rp->number].reduction_table = rp; - } - - /* Initializing the lookaheads members. Please note that it must be - performed after having set some of the other members which are - used below. Change with extreme caution. */ - { - int i; - int count = 0; - for (i = 0; i < nstates; i++) - { - int k; - reductions *rp = state_table[i].reduction_table; - shifts *sp = state_table[i].shift_table; - - state_table[i].lookaheads = count; - - if (rp - && (rp->nreds > 1 - || (sp && !ISVAR (state_table[sp->shifts[0]].accessing_symbol)))) - count += rp->nreds; - else - state_table[i].consistent = 1; - - if (sp) - for (k = 0; k < sp->nshifts; k++) - if (state_table[sp->shifts[k]].accessing_symbol - == error_token_number) - { - state_table[i].consistent = 0; - break; - } - } - state_table[nstates].lookaheads = count; - } -} - - static void initialize_LA (void) { @@ -203,7 +139,7 @@ initialize_LA (void) short *np; reductions *rp; - size_t nLA = state_table[nstates].lookaheads; + /* Avoid having to special case 0. */ if (!nLA) nLA = 1; @@ -213,8 +149,8 @@ initialize_LA (void) np = LAruleno; for (i = 0; i < nstates; i++) - if (!state_table[i].consistent) - if ((rp = state_table[i].reduction_table)) + if (!state_table[i]->consistent) + if ((rp = state_table[i]->reductions)) for (j = 0; j < rp->nreds; j++) *np++ = rp->rules[j]; } @@ -223,26 +159,19 @@ initialize_LA (void) static void set_goto_map (void) { - shifts *sp; - int i; - int symbol; - int k; + int state, i; short *temp_map; - int state2; - int state1; goto_map = XCALLOC (short, nvars + 1) - ntokens; temp_map = XCALLOC (short, nvars + 1) - ntokens; ngotos = 0; - for (sp = first_shift; sp; sp = sp->next) + for (state = 0; state < nstates; ++state) { - for (i = sp->nshifts - 1; i >= 0; i--) + shifts *sp = state_table[state]->shifts; + for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i) { - symbol = state_table[sp->shifts[i]].accessing_symbol; - - if (ISTOKEN (symbol)) - break; + int symbol = state_table[sp->shifts[i]]->accessing_symbol; if (ngotos == MAXSHORT) fatal (_("too many gotos (max %d)"), MAXSHORT); @@ -252,35 +181,34 @@ set_goto_map (void) } } - k = 0; - for (i = ntokens; i < nsyms; i++) - { - temp_map[i] = k; - k += goto_map[i]; - } + { + int k = 0; + for (i = ntokens; i < nsyms; i++) + { + temp_map[i] = k; + k += goto_map[i]; + } - for (i = ntokens; i < nsyms; i++) - goto_map[i] = temp_map[i]; + for (i = ntokens; i < nsyms; i++) + goto_map[i] = temp_map[i]; - goto_map[nsyms] = ngotos; - temp_map[nsyms] = ngotos; + goto_map[nsyms] = ngotos; + temp_map[nsyms] = ngotos; + } from_state = XCALLOC (short, ngotos); to_state = XCALLOC (short, ngotos); - for (sp = first_shift; sp; sp = sp->next) + for (state = 0; state < nstates; ++state) { - state1 = sp->number; - for (i = sp->nshifts - 1; i >= 0; i--) + shifts *sp = state_table[state]->shifts; + for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i) { - state2 = sp->shifts[i]; - symbol = state_table[state2].accessing_symbol; + int state2 = sp->shifts[i]; + int symbol = state_table[state2]->accessing_symbol; - if (ISTOKEN (symbol)) - break; - - k = temp_map[symbol]++; - from_state[k] = state1; + int k = temp_map[symbol]++; + from_state[k] = state; to_state[k] = state2; } } @@ -337,33 +265,28 @@ initialize_F (void) for (i = 0; i < ngotos; i++) { int stateno = to_state[i]; - shifts *sp = state_table[stateno].shift_table; + shifts *sp = state_table[stateno]->shifts; - if (sp) + int j; + for (j = 0; j < sp->nshifts && SHIFT_IS_SHIFT (sp, j); j++) { - int j; - for (j = 0; j < sp->nshifts; j++) - { - int symbol = state_table[sp->shifts[j]].accessing_symbol; - if (ISVAR (symbol)) - break; - SETBIT (F + i * tokensetsize, symbol); - } + int symbol = state_table[sp->shifts[j]]->accessing_symbol; + SETBIT (F (i), symbol); + } - for (; j < sp->nshifts; j++) - { - int symbol = state_table[sp->shifts[j]].accessing_symbol; - if (nullable[symbol]) - edge[nedges++] = map_goto (stateno, symbol); - } + for (; j < sp->nshifts; j++) + { + int symbol = state_table[sp->shifts[j]]->accessing_symbol; + if (nullable[symbol]) + edge[nedges++] = map_goto (stateno, symbol); + } - if (nedges) - { - reads[i] = XCALLOC (short, nedges + 1); - shortcpy (reads[i], edge, nedges); - reads[i][nedges] = -1; - nedges = 0; - } + if (nedges) + { + reads[i] = XCALLOC (short, nedges + 1); + shortcpy (reads[i], edge, nedges); + reads[i][nedges] = -1; + nedges = 0; } } @@ -378,30 +301,21 @@ initialize_F (void) static void -add_lookback_edge (int stateno, int ruleno, int gotono) +add_lookback_edge (state_t *state, int ruleno, int gotono) { int i; - int k; - int found; shorts *sp; - i = state_table[stateno].lookaheads; - k = state_table[stateno + 1].lookaheads; - found = 0; - while (!found && i < k) - { - if (LAruleno[i] == ruleno) - found = 1; - else - i++; - } + for (i = 0; i < state->nlookaheads; ++i) + if (LAruleno[state->lookaheadsp + i] == ruleno) + break; - assert (found); + assert (LAruleno[state->lookaheadsp + i] == ruleno); sp = XCALLOC (shorts, 1); - sp->next = lookback[i]; + sp->next = lookback[state->lookaheadsp + i]; sp->value = gotono; - lookback[i] = sp; + lookback[state->lookaheadsp + i] = sp; } @@ -503,34 +417,33 @@ build_relations (void) for (i = 0; i < ngotos; i++) { int nedges = 0; - int state1 = from_state[i]; - int symbol1 = state_table[to_state[i]].accessing_symbol; + int symbol1 = state_table[to_state[i]]->accessing_symbol; short *rulep; for (rulep = derives[symbol1]; *rulep > 0; rulep++) { int done; int length = 1; - int stateno = state1; short *rp; - states[0] = state1; + state_t *state = state_table[from_state[i]]; + states[0] = state->number; for (rp = ritem + rule_table[*rulep].rhs; *rp > 0; rp++) { - shifts *sp = state_table[stateno].shift_table; + shifts *sp = state->shifts; int j; for (j = 0; j < sp->nshifts; j++) { - stateno = sp->shifts[j]; - if (state_table[stateno].accessing_symbol == *rp) + state = state_table[sp->shifts[j]]; + if (state->accessing_symbol == *rp) break; } - states[length++] = stateno; + states[length++] = state->number; } - if (!state_table[stateno].consistent) - add_lookback_edge (stateno, *rulep, i); + if (!state->consistent) + add_lookback_edge (state, *rulep, i); length--; done = 0; @@ -541,8 +454,7 @@ build_relations (void) /* JF added rp>=ritem && I hope to god its right! */ if (rp >= ritem && ISVAR (*rp)) { - stateno = states[--length]; - edge[nedges++] = map_goto (stateno, *rp); + edge[nedges++] = map_goto (states[--length], *rp); if (nullable[*rp]) done = 0; } @@ -584,10 +496,10 @@ compute_FOLLOWS (void) static void compute_lookaheads (void) { - int i; + size_t i; shorts *sp; - for (i = 0; i < state_table[nstates].lookaheads; i++) + for (i = 0; i < nLA; i++) for (sp = lookback[i]; sp; sp = sp->next) { int size = LA (i + 1) - LA (i); @@ -597,7 +509,7 @@ compute_lookaheads (void) } /* Free LOOKBACK. */ - for (i = 0; i < state_table[nstates].lookaheads; i++) + for (i = 0; i < nLA; i++) LIST_FREE (shorts, lookback[i]); XFREE (lookback); @@ -605,12 +517,47 @@ compute_lookaheads (void) } +/*--------------------------------------. +| Initializing the lookaheads members. | +`--------------------------------------*/ + +static void +initialize_lookaheads (void) +{ + int i; + nLA = 0; + for (i = 0; i < nstates; i++) + { + int k; + int nlookaheads = 0; + reductions *rp = state_table[i]->reductions; + shifts *sp = state_table[i]->shifts; + + if (rp + && (rp->nreds > 1 || (sp->nshifts && SHIFT_IS_SHIFT (sp, 0)))) + nlookaheads += rp->nreds; + else + state_table[i]->consistent = 1; + + for (k = 0; k < sp->nshifts; k++) + if (SHIFT_IS_ERROR (sp, k)) + { + state_table[i]->consistent = 0; + break; + } + + state_table[i]->nlookaheads = nlookaheads; + state_table[i]->lookaheadsp = nLA; + nLA += nlookaheads; + } +} + void lalr (void) { tokensetsize = WORDSIZE (ntokens); - set_state_table (); + initialize_lookaheads (); initialize_LA (); set_goto_map (); initialize_F ();