X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/c2713865e3d0b2321949749fe16152fe1e558c69..616429b50868bf9225d55143526442a024e32969:/src/lalr.c diff --git a/src/lalr.c b/src/lalr.c index 674a121a..c16c6f52 100644 --- a/src/lalr.c +++ b/src/lalr.c @@ -24,32 +24,30 @@ tokens they accept. */ #include "system.h" +#include "reader.h" #include "types.h" #include "LR0.h" +#include "symtab.h" #include "gram.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; +/* All the decorated states, indexed by the state number. */ +state_t **states = 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; @@ -57,11 +55,20 @@ 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) @@ -97,7 +104,7 @@ traverse (int i) break; for (k = 0; k < size; ++k) - F (i)[k] = F (j)[k]; + F (j)[k] = F (i)[k]; } } @@ -126,83 +133,14 @@ 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) { int i; int j; short *np; - reductions *rp; - size_t nLA = state_table[nstates].lookaheads; + /* Avoid having to special case 0. */ if (!nLA) nLA = 1; @@ -212,75 +150,61 @@ initialize_LA (void) np = LAruleno; 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->nreds; j++) + *np++ = states[i]->reductions->rules[j]; } 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 = states[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; - if (ngotos == MAXSHORT) fatal (_("too many gotos (max %d)"), MAXSHORT); ngotos++; - goto_map[symbol]++; + goto_map[SHIFT_SYMBOL (sp, i)]++; } } - 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 = states[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; - - if (ISTOKEN (symbol)) - break; - - k = temp_map[symbol]++; - from_state[k] = state1; - to_state[k] = state2; + int k = temp_map[SHIFT_SYMBOL (sp, i)]++; + from_state[k] = state; + to_state[k] = sp->shifts[i]; } } @@ -336,33 +260,25 @@ initialize_F (void) for (i = 0; i < ngotos; i++) { int stateno = to_state[i]; - shifts *sp = state_table[stateno].shift_table; + shifts *sp = states[stateno]->shifts; - if (sp) - { - 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 j; + for (j = 0; j < sp->nshifts && SHIFT_IS_SHIFT (sp, j); j++) + SETBIT (F (i), SHIFT_SYMBOL (sp, j)); - 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 = SHIFT_SYMBOL (sp, j); + 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; } } @@ -377,86 +293,105 @@ 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; } +static void +matrix_print (FILE *out, short **matrix, int n) +{ + int i, j; + + for (i = 0; i < n; ++i) + { + fprintf (out, "%3d: ", i); + if (matrix[i]) + for (j = 0; matrix[i][j] != -1; ++j) + fprintf (out, "%3d ", matrix[i][j]); + fputc ('\n', out); + } + fputc ('\n', out); +} + /*-------------------------------------------------------------------. | Return the transpose of R_ARG, of size N. Destroy R_ARG, as it is | | replaced with the result. | +| | +| R_ARG[I] is NULL or a -1 terminated list of numbers. | +| | +| RESULT[NUM] is NULL or the -1 terminated list of the I such as NUM | +| is in R_ARG[I]. | `-------------------------------------------------------------------*/ static short ** transpose (short **R_arg, int n) { - short **new_R; - short **temp_R; - short *nedges; - int i; - - nedges = XCALLOC (short, n); - - for (i = 0; i < n; i++) + /* The result. */ + short **new_R = XCALLOC (short *, n); + /* END_R[I] -- next entry of NEW_R[I]. */ + short **end_R = XCALLOC (short *, n); + /* NEDGES[I] -- total size of NEW_R[I]. */ + short *nedges = XCALLOC (short, n); + int i, j; + + if (trace_flag) { - short *sp = R_arg[i]; - if (sp) - { - while (*sp >= 0) - nedges[*sp++]++; - } + fputs ("transpose: input\n", stderr); + matrix_print (stderr, R_arg, n); } - new_R = XCALLOC (short *, n); - temp_R = XCALLOC (short *, n); + /* Count. */ + for (i = 0; i < n; i++) + if (R_arg[i]) + for (j = 0; R_arg[i][j] >= 0; ++j) + ++nedges[R_arg[i][j]]; + /* Allocate. */ for (i = 0; i < n; i++) if (nedges[i] > 0) { short *sp = XCALLOC (short, nedges[i] + 1); - new_R[i] = sp; - temp_R[i] = sp; sp[nedges[i]] = -1; + new_R[i] = sp; + end_R[i] = sp; } - XFREE (nedges); - + /* Store. */ for (i = 0; i < n; i++) - { - short *sp = R_arg[i]; - if (sp) - while (*sp >= 0) - *temp_R[*sp++]++ = i; - } + if (R_arg[i]) + for (j = 0; R_arg[i][j] >= 0; ++j) + { + *end_R[R_arg[i][j]] = i; + ++end_R[R_arg[i][j]]; + } - XFREE (temp_R); + free (nedges); + free (end_R); /* Free the input: it is replaced with the result. */ for (i = 0; i < n; i++) XFREE (R_arg[i]); - XFREE (R_arg); + free (R_arg); + + if (trace_flag) + { + fputs ("transpose: output\n", stderr); + matrix_print (stderr, new_R, n); + } return new_R; } @@ -466,7 +401,7 @@ static void build_relations (void) { short *edge = XCALLOC (short, ngotos + 1); - short *states = XCALLOC (short, ritem_longest_rhs () + 1); + short *states1 = XCALLOC (short, ritem_longest_rhs () + 1); int i; includes = XCALLOC (short *, ngotos); @@ -474,34 +409,33 @@ 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 = states[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 = states[from_state[i]]; + states1[0] = state->number; - for (rp = ritem + rule_table[*rulep].rhs; *rp > 0; rp++) + for (rp = &ritem[rules[*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 = states[sp->shifts[j]]; + if (state->accessing_symbol == *rp) break; } - states[length++] = stateno; + 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; @@ -512,8 +446,7 @@ 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 (states1[--length], *rp); if (nullable[*rp]) done = 0; } @@ -531,7 +464,7 @@ build_relations (void) } XFREE (edge); - XFREE (states); + XFREE (states1); includes = transpose (includes, ngotos); } @@ -555,10 +488,10 @@ 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); @@ -568,7 +501,7 @@ 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); @@ -576,16 +509,83 @@ 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 = states[i]->reductions; + shifts *sp = states[i]->shifts; + + /* 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->nreds > 1 + || (rp->nreds == 1 && sp->nshifts && SHIFT_IS_SHIFT (sp, 0))) + nlookaheads += rp->nreds; + else + states[i]->consistent = 1; + + for (k = 0; k < sp->nshifts; k++) + if (SHIFT_IS_ERROR (sp, k)) + { + states[i]->consistent = 0; + break; + } + + states[i]->nlookaheads = nlookaheads; + states[i]->lookaheadsp = nLA; + nLA += nlookaheads; + } +} + + +/*---------------------------------------. +| Output the lookaheads for each state. | +`---------------------------------------*/ + +static void +lookaheads_print (FILE *out) +{ + int i, j, k; + fprintf (out, "Lookaheads: BEGIN\n"); + for (i = 0; i < nstates; ++i) + { + fprintf (out, "State %d: %d lookaheads\n", + i, states[i]->nlookaheads); + + for (j = 0; j < states[i]->nlookaheads; ++j) + for (k = 0; k < ntokens; ++k) + if (BITISSET (LA (states[i]->lookaheadsp + j), j)) + fprintf (out, " on %d (%s) -> rule %d\n", + k, symbols[k]->tag, + -LAruleno[states[i]->lookaheadsp + j] - 1); + } + fprintf (out, "Lookaheads: END\n"); +} + void lalr (void) { tokensetsize = WORDSIZE (ntokens); - set_state_table (); + initialize_lookaheads (); initialize_LA (); set_goto_map (); initialize_F (); build_relations (); compute_FOLLOWS (); compute_lookaheads (); + + if (trace_flag) + lookaheads_print (stderr); }