X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/de326cc0de0e14b33c64d40171eb74640ff2e20a..c76e14da4bf475d4f85090d5fdde85d8dddb5833:/src/lalr.c diff --git a/src/lalr.c b/src/lalr.c index d4795b57..d07f19bb 100644 --- a/src/lalr.c +++ b/src/lalr.c @@ -1,5 +1,6 @@ /* Compute look-ahead criteria for bison, - Copyright 1984, 1986, 1989, 2000 Free Software Foundation, Inc. + Copyright (C) 1984, 1986, 1989, 2000, 2001, 2002 + Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -24,307 +25,123 @@ tokens they accept. */ #include "system.h" -#include "types.h" -#include "LR0.h" +#include "bitset.h" +#include "bitsetv.h" +#include "relation.h" +#include "quotearg.h" +#include "symtab.h" #include "gram.h" +#include "reader.h" +#include "LR0.h" #include "complain.h" #include "lalr.h" #include "nullable.h" #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; - -int tokensetsize; -short *lookaheads; -short *LAruleno; -unsigned *LA; - -short *goto_map; -short *from_state; -short *to_state; - -extern void berror PARAMS ((const char *)); - -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; - - -static void -traverse (int i) -{ - unsigned *fp1; - unsigned *fp2; - unsigned *fp3; - int j; - 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) - { - 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++; - } - } - - 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++; - } - } -} - - -static void -digraph (short **relation) -{ - int i; - - infinity = ngotos + 2; - INDEX = XCALLOC (short, ngotos + 1); - VERTICES = XCALLOC (short, ngotos + 1); - top = 0; - - R = relation; +goto_number_t *goto_map = NULL; +static goto_number_t ngotos = 0; +state_number_t *from_state = NULL; +state_number_t *to_state = NULL; - for (i = 0; i < ngotos; i++) - INDEX[i] = 0; - - for (i = 0; i < ngotos; i++) - { - if (INDEX[i] == 0 && R[i]) - traverse (i); - } - - XFREE (INDEX); - XFREE (VERTICES); -} - -static void -set_state_table (void) +/* Linked list of goto numbers. */ +typedef struct goto_list_s { - state_table = XCALLOC (state_t, nstates); + struct goto_list_s *next; + goto_number_t value; +} goto_list_t; - { - 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; - } +rule_t **LArule = NULL; +bitsetv LA = NULL; +size_t nLA; - { - reductions *rp; - for (rp = first_reduction; rp; rp = rp->next) - state_table[rp->number].reduction_table = rp; - } -} +/* And for the famous F variable, which name is so descriptive that a + comment is hardly needed. . */ +static bitsetv F = NULL; -static void -set_maxrhs (void) -{ - short *itemp; - int length; - int max; +static goto_number_t **includes; +static goto_list_t **lookback; - length = 0; - max = 0; - for (itemp = ritem; *itemp; itemp++) - { - if (*itemp > 0) - { - length++; - } - else - { - if (length > max) - max = length; - length = 0; - } - } - maxrhs = max; -} static void initialize_LA (void) { - int i; + state_number_t i; int j; - int count; - reductions *rp; - shifts *sp; - short *np; - - lookaheads = XCALLOC (short, nstates + 1); - - count = 0; - for (i = 0; i < nstates; i++) - { - int k; - - lookaheads[i] = count; - - rp = state_table[i].reduction_table; - sp = state_table[i].shift_table; - 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; - } - } + rule_t **np; - lookaheads[nstates] = count; + /* Avoid having to special case 0. */ + if (!nLA) + nLA = 1; - if (count == 0) - { - LA = XCALLOC (unsigned, 1 * tokensetsize); - LAruleno = XCALLOC (short, 1); - lookback = XCALLOC (shorts *, 1); - } - else - { - LA = XCALLOC (unsigned, count * tokensetsize); - LAruleno = XCALLOC (short, count); - lookback = XCALLOC (shorts *, count); - } + LA = bitsetv_create (nLA, ntokens, BITSET_FIXED); + LArule = XCALLOC (rule_t *, nLA); + lookback = XCALLOC (goto_list_t *, nLA); - np = LAruleno; + np = LArule; for (i = 0; i < nstates; i++) - { - if (!state_table[i].consistent) - { - if ((rp = state_table[i].reduction_table)) - for (j = 0; j < rp->nreds; j++) - *np++ = rp->rules[j]; - } - } + 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) { - shifts *sp; - int i; - int symbol; - int k; - short *temp_map; - int state2; - int state1; + state_number_t state; + 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 (sp = first_shift; sp; sp = sp->next) + for (state = 0; state < nstates; ++state) { - for (i = sp->nshifts - 1; i >= 0; i--) + transitions_t *sp = states[state]->transitions; + int i; + for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i) { - symbol = state_table[sp->shifts[i]].accessing_symbol; - - if (ISTOKEN (symbol)) - break; - - if (ngotos == MAXSHORT) - fatal (_("too many gotos (max %d)"), MAXSHORT); + if (ngotos == GOTO_NUMBER_MAX) + fatal (_("too many gotos (max %d)"), GOTO_NUMBER_MAX); ngotos++; - goto_map[symbol]++; + goto_map[TRANSITION_SYMBOL (sp, i)]++; } } - k = 0; - for (i = ntokens; i < nsyms; i++) - { - temp_map[i] = k; - k += goto_map[i]; - } + { + int k = 0; + int i; + 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); + from_state = XCALLOC (state_number_t, ngotos); + to_state = XCALLOC (state_number_t, 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--) + transitions_t *sp = states[state]->transitions; + int i; + for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i) { - state2 = sp->shifts[i]; - symbol = state_table[state2].accessing_symbol; - - if (ISTOKEN (symbol)) - break; - - k = temp_map[symbol]++; - from_state[k] = state1; - to_state[k] = state2; + int k = temp_map[TRANSITION_SYMBOL (sp, i)]++; + from_state[k] = state; + to_state[k] = sp->states[i]; } } @@ -338,12 +155,12 @@ set_goto_map (void) `----------------------------------------------------------*/ static int -map_goto (int state, int symbol) +map_goto (state_number_t state, symbol_number_t symbol) { int high; int low; int middle; - int s; + state_number_t s; low = goto_map[symbol]; high = goto_map[symbol + 1] - 1; @@ -369,73 +186,43 @@ map_goto (int state, int symbol) static void initialize_F (void) { - int i; - int j; - int k; - shifts *sp; - short *edge; - unsigned *rowp; - short *rp; - short **reads; - int nedges; - int stateno; - int symbol; - int nwords; - - nwords = ngotos * tokensetsize; - F = XCALLOC (unsigned, nwords); - - reads = XCALLOC (short *, ngotos); - edge = XCALLOC (short, ngotos + 1); - nedges = 0; - - rowp = F; - for (i = 0; i < ngotos; i++) - { - stateno = to_state[i]; - sp = state_table[stateno].shift_table; + goto_number_t **reads = XCALLOC (goto_number_t *, ngotos); + goto_number_t *edge = XCALLOC (goto_number_t, ngotos + 1); + int nedges = 0; - if (sp) - { - k = sp->nshifts; + int i; - for (j = 0; j < k; j++) - { - symbol = state_table[sp->shifts[j]].accessing_symbol; - if (ISVAR (symbol)) - break; - SETBIT (rowp, symbol); - } + F = bitsetv_create (ngotos, ntokens, BITSET_FIXED); - for (; j < k; j++) - { - symbol = state_table[sp->shifts[j]].accessing_symbol; - if (nullable[symbol]) - edge[nedges++] = map_goto (stateno, symbol); - } - - if (nedges) - { - reads[i] = rp = XCALLOC (short, nedges + 1); + for (i = 0; i < ngotos; i++) + { + state_number_t stateno = to_state[i]; + transitions_t *sp = states[stateno]->transitions; - for (j = 0; j < nedges; j++) - rp[j] = edge[j]; + int j; + for (j = 0; j < sp->num && TRANSITION_IS_SHIFT (sp, j); j++) + bitset_set (F[i], TRANSITION_SYMBOL (sp, j)); - rp[nedges] = -1; - nedges = 0; - } + for (; j < sp->num; j++) + { + symbol_number_t symbol = TRANSITION_SYMBOL (sp, j); + if (nullable[symbol]) + edge[nedges++] = map_goto (stateno, symbol); } - rowp += tokensetsize; + if (nedges) + { + reads[i] = XCALLOC (goto_number_t, nedges + 1); + memcpy (reads[i], edge, nedges * sizeof (edge[0])); + reads[i][nedges] = -1; + nedges = 0; + } } - digraph (reads); + relation_digraph (reads, ngotos, &F); for (i = 0; i < ngotos; i++) - { - if (reads[i]) - XFREE (reads[i]); - } + XFREE (reads[i]); XFREE (reads); XFREE (edge); @@ -443,143 +230,57 @@ initialize_F (void) static void -add_lookback_edge (int stateno, int ruleno, int gotono) +add_lookback_edge (state_t *state, rule_number_t ruleno, int gotono) { int i; - int k; - int found; - shorts *sp; - - i = lookaheads[stateno]; - k = lookaheads[stateno + 1]; - found = 0; - while (!found && i < k) - { - if (LAruleno[i] == ruleno) - found = 1; - else - i++; - } + goto_list_t *sp; + + for (i = 0; i < state->nlookaheads; ++i) + if (state->lookaheads_rule[i]->number == ruleno) + break; - assert (found); + assert (state->lookaheads_rule[i]->number == ruleno); - sp = XCALLOC (shorts, 1); - sp->next = lookback[i]; + sp = XCALLOC (goto_list_t, 1); + sp->next = lookback[(state->lookaheads - LA) + i]; sp->value = gotono; - lookback[i] = sp; + lookback[(state->lookaheads - LA) + i] = sp; } -static short ** -transpose (short **R_arg, int n) -{ - short **new_R; - short **temp_R; - short *nedges; - short *sp; - int i; - int k; - - nedges = XCALLOC (short, n); - - for (i = 0; i < n; i++) - { - sp = R_arg[i]; - if (sp) - { - while (*sp >= 0) - nedges[*sp++]++; - } - } - - new_R = XCALLOC (short *, n); - temp_R = XCALLOC (short *, n); - - for (i = 0; i < n; i++) - { - k = nedges[i]; - if (k > 0) - { - sp = XCALLOC (short, k + 1); - new_R[i] = sp; - temp_R[i] = sp; - sp[k] = -1; - } - } - - XFREE (nedges); - - for (i = 0; i < n; i++) - { - sp = R_arg[i]; - if (sp) - { - while (*sp >= 0) - *temp_R[*sp++]++ = i; - } - } - - XFREE (temp_R); - - return new_R; -} - static void build_relations (void) { + goto_number_t *edge = XCALLOC (goto_number_t, ngotos + 1); + state_number_t *states1 = XCALLOC (state_number_t, ritem_longest_rhs () + 1); int i; - int j; - int k; - short *rulep; - short *rp; - shifts *sp; - int length; - int nedges; - int done; - int state1; - int stateno; - int symbol1; - int symbol2; - short *shortp; - short *edge; - short *states; - short **new_includes; - - includes = XCALLOC (short *, ngotos); - edge = XCALLOC (short, ngotos + 1); - states = XCALLOC (short, maxrhs + 1); + + includes = XCALLOC (goto_number_t *, ngotos); for (i = 0; i < ngotos; i++) { - nedges = 0; - state1 = from_state[i]; - symbol1 = state_table[to_state[i]].accessing_symbol; + int nedges = 0; + symbol_number_t symbol1 = states[to_state[i]]->accessing_symbol; + rule_number_t *rulep; for (rulep = derives[symbol1]; *rulep > 0; rulep++) { - length = 1; - states[0] = state1; - stateno = state1; + int done; + int length = 1; + item_number_t *rp; + state_t *state = states[from_state[i]]; + states1[0] = state->number; - for (rp = ritem + rrhs[*rulep]; *rp > 0; rp++) + for (rp = rules[*rulep].rhs; *rp >= 0; rp++) { - symbol2 = *rp; - sp = state_table[stateno].shift_table; - k = sp->nshifts; - - for (j = 0; j < k; j++) - { - stateno = sp->shifts[j]; - if (state_table[stateno].accessing_symbol == symbol2) - break; - } - - states[length++] = stateno; + state = transitions_to (state->transitions, + item_number_as_symbol_number (*rp)); + states1[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; @@ -590,8 +291,9 @@ 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); + /* Downcasting from item_number_t to symbol_number_t. */ + edge[nedges++] = map_goto (states1[--length], + item_number_as_symbol_number (*rp)); if (nullable[*rp]) done = 0; } @@ -600,25 +302,18 @@ build_relations (void) if (nedges) { - includes[i] = shortp = XCALLOC (short, nedges + 1); + int j; + includes[i] = XCALLOC (goto_number_t, nedges + 1); for (j = 0; j < nedges; j++) - shortp[j] = edge[j]; - shortp[nedges] = -1; + includes[i][j] = edge[j]; + includes[i][nedges] = -1; } } - new_includes = transpose (includes, ngotos); - - for (i = 0; i < ngotos; i++) - if (includes[i]) - XFREE (includes[i]); - - XFREE (includes); - - includes = new_includes; - XFREE (edge); - XFREE (states); + XFREE (states1); + + relation_transpose (&includes, ngotos); } @@ -628,13 +323,10 @@ compute_FOLLOWS (void) { int i; - digraph (includes); + relation_digraph (includes, ngotos, &F); for (i = 0; i < ngotos; i++) - { - if (includes[i]) - XFREE (includes[i]); - } + XFREE (includes[i]); XFREE (includes); } @@ -643,57 +335,127 @@ compute_FOLLOWS (void) static void compute_lookaheads (void) { - int i; - int n; - unsigned *fp1; - unsigned *fp2; - unsigned *fp3; - shorts *sp; - unsigned *rowp; - shorts *sptmp; /* JF */ - - rowp = LA; - n = lookaheads[nstates]; - for (i = 0; i < n; i++) + size_t i; + goto_list_t *sp; + + for (i = 0; i < nLA; i++) + for (sp = lookback[i]; sp; sp = sp->next) + bitset_or (LA[i], LA[i], F[sp->value]); + + /* Free LOOKBACK. */ + for (i = 0; i < nLA; 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. | +`-------------------------------------------------------------*/ + +static void +states_lookaheads_count (void) +{ + state_number_t i; + nLA = 0; + + /* Count */ + 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++; - } + 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; - rowp = fp3; + for (k = 0; k < sp->num; k++) + if (TRANSITION_IS_ERROR (sp, k)) + { + states[i]->consistent = 0; + break; + } + + states[i]->nlookaheads = nlookaheads; + nLA += nlookaheads; } +} + - for (i = 0; i < n; i++) +/*--------------------------------------. +| Initializing the lookaheads members. | +`--------------------------------------*/ + +static void +states_lookaheads_initialize (void) +{ + state_number_t i; + bitsetv pLA = LA; + rule_t **pLArule = LArule; + + /* Initialize the members LOOKAHEADS and LOOKAHEADS_RULE for each + state. */ + for (i = 0; i < nstates; i++) { - /* JF removed ref to freed storage */ - for (sp = lookback[i]; sp; sp = sptmp) - { - sptmp = sp->next; - XFREE (sp); - } + states[i]->lookaheads = pLA; + states[i]->lookaheads_rule = pLArule; + pLA += states[i]->nlookaheads; + pLArule += states[i]->nlookaheads; } - - XFREE (lookback); - XFREE (F); } +/*---------------------------------------. +| Output the lookaheads for each state. | +`---------------------------------------*/ + +static void +lookaheads_print (FILE *out) +{ + state_number_t i; + int j, k; + fprintf (out, "Lookaheads: BEGIN\n"); + for (i = 0; i < nstates; ++i) + { + bitset_iterator iter; + + fprintf (out, "State %d: %d lookaheads\n", + i, states[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); + }; + } + fprintf (out, "Lookaheads: END\n"); +} + void lalr (void) { - tokensetsize = WORDSIZE (ntokens); - - set_state_table (); - set_maxrhs (); + states_lookaheads_count (); initialize_LA (); + states_lookaheads_initialize (); set_goto_map (); initialize_F (); build_relations (); compute_FOLLOWS (); compute_lookaheads (); + + if (trace_flag) + lookaheads_print (stderr); }