X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/aa7815f5c6e8e07a85e47df9cd7b579468969efb..616429b50868bf9225d55143526442a024e32969:/src/lalr.c?ds=sidebyside diff --git a/src/lalr.c b/src/lalr.c index 7e8aff70..c16c6f52 100644 --- a/src/lalr.c +++ b/src/lalr.c @@ -1,5 +1,5 @@ /* Compute look-ahead criteria for bison, - Copyright 1984, 1986, 1989, 2000 Free Software Foundation, Inc. + Copyright 1984, 1986, 1989, 2000, 2001 Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -24,96 +24,88 @@ tokens they accept. */ #include "system.h" +#include "reader.h" #include "types.h" #include "LR0.h" -#include "xalloc.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. */ +state_t **states = NULL; int tokensetsize; -short *lookaheads; short *LAruleno; unsigned *LA; -short *accessing_symbol; -char *consistent; -core **state_table; -shifts **shift_table; -reductions **reduction_table; +size_t nLA; + +static int ngotos; short *goto_map; short *from_state; short *to_state; -extern void berror PARAMS ((const char *)); +/* And for the famous F variable, which name is so descriptive that a + comment is hardly needed. . */ +static unsigned *F = NULL; +#define F(Rule) (F + (Rule) * tokensetsize) -static int infinity; -static int maxrhs; -static int ngotos; -static unsigned *F; 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) { - unsigned *fp1; - unsigned *fp2; - unsigned *fp3; int j; - short *rp; - + size_t k; int height; - unsigned *base; + size_t size = F (i + 1) - F(i); 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]; + if (R[i]) + for (j = 0; R[i][j] >= 0; ++j) + { + if (INDEX[R[i][j]] == 0) + traverse (R[i][j]); - fp1 = base; - fp2 = F + j * tokensetsize; + if (INDEX[i] > INDEX[R[i][j]]) + INDEX[i] = INDEX[R[i][j]]; - while (fp1 < fp3) - *fp1++ |= *fp2++; - } - } + for (k = 0; k < size; ++k) + F (i)[k] |= F (R[i][j])[k]; + } if (INDEX[i] == height) - { - for (;;) - { - j = VERTICES[top--]; - INDEX[j] = infinity; - - if (i == j) - break; + for (;;) + { + j = VERTICES[top--]; + INDEX[j] = infinity; - fp1 = base; - fp2 = F + j * tokensetsize; + if (i == j) + break; - while (fp1 < fp3) - *fp2++ = *fp1++; - } - } + for (k = 0; k < size; ++k) + F (j)[k] = F (i)[k]; + } } @@ -133,219 +125,86 @@ digraph (short **relation) INDEX[i] = 0; for (i = 0; i < ngotos; i++) - { - if (INDEX[i] == 0 && R[i]) - traverse (i); - } + if (INDEX[i] == 0 && R[i]) + traverse (i); XFREE (INDEX); XFREE (VERTICES); } -static void -set_state_table (void) -{ - core *sp; - - state_table = XCALLOC (core *, nstates); - - for (sp = first_state; sp; sp = sp->next) - state_table[sp->number] = sp; -} - - -static void -set_accessing_symbol (void) -{ - core *sp; - - accessing_symbol = XCALLOC (short, nstates); - - for (sp = first_state; sp; sp = sp->next) - accessing_symbol[sp->number] = sp->accessing_symbol; -} - - -static void -set_shift_table (void) -{ - shifts *sp; - - shift_table = XCALLOC (shifts *, nstates); - - for (sp = first_shift; sp; sp = sp->next) - shift_table[sp->number] = sp; -} - - -static void -set_reduction_table (void) -{ - reductions *rp; - - reduction_table = XCALLOC (reductions *, nstates); - - for (rp = first_reduction; rp; rp = rp->next) - reduction_table[rp->number] = rp; -} - - -static void -set_maxrhs (void) -{ - short *itemp; - int length; - 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; -} - static void initialize_LA (void) { int i; int j; - int count; - reductions *rp; - shifts *sp; short *np; - consistent = XCALLOC (char, nstates); - lookaheads = XCALLOC (short, nstates + 1); - - count = 0; - for (i = 0; i < nstates; i++) - { - int k; + /* Avoid having to special case 0. */ + if (!nLA) + nLA = 1; - lookaheads[i] = count; - - 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; - - 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; - - 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 = XCALLOC (unsigned, nLA * tokensetsize); + LAruleno = XCALLOC (short, nLA); + lookback = XCALLOC (shorts *, nLA); 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]; - } - } + 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 = accessing_symbol[sp->shifts[i]]; - - 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 = accessing_symbol[state2]; - - 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]; } } @@ -390,73 +249,43 @@ 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 = shift_table[stateno]; - - if (sp) - { - k = sp->nshifts; + short **reads = XCALLOC (short *, ngotos); + short *edge = XCALLOC (short, ngotos + 1); + int nedges = 0; - for (j = 0; j < k; j++) - { - symbol = accessing_symbol[sp->shifts[j]]; - if (ISVAR (symbol)) - break; - SETBIT (rowp, symbol); - } + int i; - for (; j < k; j++) - { - symbol = accessing_symbol[sp->shifts[j]]; - if (nullable[symbol]) - edge[nedges++] = map_goto (stateno, symbol); - } + F = XCALLOC (unsigned, ngotos * tokensetsize); - if (nedges) - { - reads[i] = rp = XCALLOC (short, nedges + 1); + for (i = 0; i < ngotos; i++) + { + int stateno = to_state[i]; + shifts *sp = states[stateno]->shifts; - for (j = 0; j < nedges; j++) - rp[j] = edge[j]; + int j; + for (j = 0; j < sp->nshifts && SHIFT_IS_SHIFT (sp, j); j++) + SETBIT (F (i), SHIFT_SYMBOL (sp, j)); - rp[nedges] = -1; - nedges = 0; - } + for (; j < sp->nshifts; j++) + { + int symbol = SHIFT_SYMBOL (sp, j); + if (nullable[symbol]) + edge[nedges++] = map_goto (stateno, symbol); } - rowp += tokensetsize; + if (nedges) + { + reads[i] = XCALLOC (short, nedges + 1); + shortcpy (reads[i], edge, nedges); + reads[i][nedges] = -1; + nedges = 0; + } } digraph (reads); for (i = 0; i < ngotos; i++) - { - if (reads[i]) - XFREE (reads[i]); - } + XFREE (reads[i]); XFREE (reads); XFREE (edge); @@ -464,84 +293,106 @@ 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 = lookaheads[stateno]; - k = lookaheads[stateno + 1]; - 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 short ** -transpose (short **R_arg, int n) +static void +matrix_print (FILE *out, short **matrix, int n) { - short **new_R; - short **temp_R; - short *nedges; - short *sp; - int i; - int k; + 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); +} - nedges = XCALLOC (short, n); +/*-------------------------------------------------------------------. +| 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]. | +`-------------------------------------------------------------------*/ - for (i = 0; i < n; i++) +static short ** +transpose (short **R_arg, int n) +{ + /* 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) { - 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++) - { - k = nedges[i]; - if (k > 0) + if (nedges[i] > 0) + { + short *sp = XCALLOC (short, nedges[i] + 1); + sp[nedges[i]] = -1; + new_R[i] = sp; + end_R[i] = sp; + } + + /* Store. */ + for (i = 0; i < n; i++) + if (R_arg[i]) + for (j = 0; R_arg[i][j] >= 0; ++j) { - sp = XCALLOC (short, k + 1); - new_R[i] = sp; - temp_R[i] = sp; - sp[k] = -1; + *end_R[R_arg[i][j]] = i; + ++end_R[R_arg[i][j]]; } - } - XFREE (nedges); + free (nedges); + free (end_R); + /* Free the input: it is replaced with the result. */ for (i = 0; i < n; i++) + XFREE (R_arg[i]); + free (R_arg); + + if (trace_flag) { - sp = R_arg[i]; - if (sp) - { - while (*sp >= 0) - *temp_R[*sp++]++ = i; - } + fputs ("transpose: output\n", stderr); + matrix_print (stderr, new_R, n); } - XFREE (temp_R); - return new_R; } @@ -549,58 +400,42 @@ transpose (short **R_arg, int n) static void build_relations (void) { + short *edge = XCALLOC (short, ngotos + 1); + short *states1 = XCALLOC (short, 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); for (i = 0; i < ngotos; i++) { - nedges = 0; - state1 = from_state[i]; - symbol1 = accessing_symbol[to_state[i]]; + int nedges = 0; + int symbol1 = states[to_state[i]]->accessing_symbol; + short *rulep; for (rulep = derives[symbol1]; *rulep > 0; rulep++) { - length = 1; - states[0] = state1; - stateno = state1; + int done; + int length = 1; + short *rp; + state_t *state = states[from_state[i]]; + states1[0] = state->number; - for (rp = ritem + rrhs[*rulep]; *rp > 0; rp++) + for (rp = &ritem[rules[*rulep].rhs]; *rp >= 0; rp++) { - symbol2 = *rp; - sp = shift_table[stateno]; - k = sp->nshifts; - - for (j = 0; j < k; j++) + shifts *sp = state->shifts; + int j; + for (j = 0; j < sp->nshifts; j++) { - stateno = sp->shifts[j]; - if (accessing_symbol[stateno] == symbol2) + state = states[sp->shifts[j]]; + if (state->accessing_symbol == *rp) break; } - states[length++] = stateno; + states1[length++] = state->number; } - if (!consistent[stateno]) - add_lookback_edge (stateno, *rulep, i); + if (!state->consistent) + add_lookback_edge (state, *rulep, i); length--; done = 0; @@ -611,8 +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; } @@ -621,25 +455,18 @@ build_relations (void) if (nedges) { - includes[i] = shortp = XCALLOC (short, nedges + 1); + int j; + includes[i] = XCALLOC (short, 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); + + includes = transpose (includes, ngotos); } @@ -652,10 +479,7 @@ compute_FOLLOWS (void) digraph (includes); for (i = 0; i < ngotos; i++) - { - if (includes[i]) - XFREE (includes[i]); - } + XFREE (includes[i]); XFREE (includes); } @@ -664,60 +488,104 @@ compute_FOLLOWS (void) static void compute_lookaheads (void) { - int i; - int n; - unsigned *fp1; - unsigned *fp2; - unsigned *fp3; + size_t i; shorts *sp; - unsigned *rowp; - shorts *sptmp; /* JF */ - rowp = LA; - n = lookaheads[nstates]; - for (i = 0; i < n; i++) + for (i = 0; i < nLA; i++) + for (sp = lookback[i]; sp; sp = sp->next) + { + int size = LA (i + 1) - LA (i); + int j; + for (j = 0; j < size; ++j) + LA (i)[j] |= F (sp->value)[j]; + } + + /* Free LOOKBACK. */ + for (i = 0; i < nLA; i++) + LIST_FREE (shorts, lookback[i]); + + XFREE (lookback); + XFREE (F); +} + + +/*--------------------------------------. +| Initializing the lookaheads members. | +`--------------------------------------*/ + +static void +initialize_lookaheads (void) +{ + int i; + nLA = 0; + 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 *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; - rowp = fp3; + 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; } +} - for (i = 0; i < n; i++) + +/*---------------------------------------. +| 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) { - /* JF removed ref to freed storage */ - for (sp = lookback[i]; sp; sp = sptmp) - { - sptmp = sp->next; - XFREE (sp); - } + 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); } - - XFREE (lookback); - XFREE (F); + fprintf (out, "Lookaheads: END\n"); } - void lalr (void) { tokensetsize = WORDSIZE (ntokens); - set_state_table (); - set_accessing_symbol (); - set_shift_table (); - set_reduction_table (); - set_maxrhs (); + initialize_lookaheads (); initialize_LA (); set_goto_map (); initialize_F (); build_relations (); compute_FOLLOWS (); compute_lookaheads (); + + if (trace_flag) + lookaheads_print (stderr); }