/* * Copyright (c) 1989 The Regents of the University of California. * All rights reserved. * * This code is derived from software contributed to Berkeley by * Robert Paul Corbett. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #if 0 #ifndef lint static char sccsid[] = "@(#)lalr.c 5.3 (Berkeley) 6/1/90"; #endif #endif #include <sys/cdefs.h> __FBSDID("$FreeBSD$"); #include <limits.h> #include <stdlib.h> #include "defs.h" typedef struct shorts { struct shorts *next; short value; } shorts; int tokensetsize; short *lookaheads; short *LAruleno; unsigned *LA; short *accessing_symbol; core **state_table; shifts **shift_table; reductions **reduction_table; short *goto_map; short *from_state; short *to_state; static void add_lookback_edge(int, int, int); static void build_relations(void); static void compute_FOLLOWS(void); static void compute_lookaheads(void); static void digraph(short **); static void initialize_F(void); static void initialize_LA(void); static int map_goto(int, int); static void set_accessing_symbol(void); static void set_goto_map(void); static void set_maxrhs(void); static void set_reduction_table(void); static void set_shift_table(void); static void set_state_table(void); static short **transpose(short **, int); static void traverse(int, short **); static int infinity; static int maxrhs; static int ngotos; static unsigned *F; static short **includes; static shorts **lookback; 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(); } static void set_state_table() { core *sp; state_table = NEW2(nstates, core *); for (sp = first_state; sp; sp = sp->next) state_table[sp->number] = sp; } static void set_accessing_symbol() { core *sp; accessing_symbol = NEW2(nstates, short); for (sp = first_state; sp; sp = sp->next) accessing_symbol[sp->number] = sp->accessing_symbol; } static void set_shift_table() { shifts *sp; shift_table = NEW2(nstates, shifts *); for (sp = first_shift; sp; sp = sp->next) shift_table[sp->number] = sp; } static void set_reduction_table() { reductions *rp; reduction_table = NEW2(nstates, reductions *); for (rp = first_reduction; rp; rp = rp->next) reduction_table[rp->number] = rp; } static void set_maxrhs() { short *itemp; short *item_end; int length; int max; length = 0; max = 0; item_end = ritem + nitems; for (itemp = ritem; itemp < item_end; itemp++) { if (*itemp >= 0) { length++; } else { if (length > max) max = length; length = 0; } } maxrhs = max; } static void initialize_LA() { int i, j, k; reductions *rp; lookaheads = NEW2(nstates + 1, short); k = 0; for (i = 0; i < nstates; i++) { lookaheads[i] = k; rp = reduction_table[i]; if (rp) k += rp->nreds; } lookaheads[nstates] = k; LA = NEW2(k * tokensetsize, unsigned); LAruleno = NEW2(k, short); lookback = NEW2(k, shorts *); k = 0; for (i = 0; i < nstates; i++) { rp = reduction_table[i]; if (rp) { for (j = 0; j < rp->nreds; j++) { LAruleno[k] = rp->rules[j]; k++; } } } } static void set_goto_map() { shifts *sp; int i; int symbol; int k; short *temp_map; int state2; int state1; goto_map = NEW2(nvars + 1, short) - ntokens; temp_map = NEW2(nvars + 1, short) - ntokens; ngotos = 0; for (sp = first_shift; sp; sp = sp->next) { for (i = sp->nshifts - 1; i >= 0; i--) { symbol = accessing_symbol[sp->shift[i]]; if (ISTOKEN(symbol)) break; if (ngotos == SHRT_MAX) fatal("too many gotos"); ngotos++; goto_map[symbol]++; } } 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]; goto_map[nsyms] = ngotos; temp_map[nsyms] = ngotos; from_state = NEW2(ngotos, short); to_state = NEW2(ngotos, short); for (sp = first_shift; sp; sp = sp->next) { state1 = sp->number; for (i = sp->nshifts - 1; i >= 0; i--) { state2 = sp->shift[i]; symbol = accessing_symbol[state2]; if (ISTOKEN(symbol)) break; k = temp_map[symbol]++; from_state[k] = state1; to_state[k] = state2; } } FREE(temp_map + ntokens); } /* Map_goto maps a state/symbol pair into its numeric representation. */ static int map_goto(state, symbol) int state; int symbol; { int high; int low; int middle; int s; low = goto_map[symbol]; high = goto_map[symbol + 1]; for (;;) { assert(low <= high); middle = (low + high) >> 1; s = from_state[middle]; if (s == state) return (middle); else if (s < state) low = middle + 1; else high = middle - 1; } } static void initialize_F() { 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 = 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]; if (sp) { k = sp->nshifts; for (j = 0; j < k; j++) { symbol = accessing_symbol[sp->shift[j]]; if (ISVAR(symbol)) break; SETBIT(rowp, symbol); } for (; j < k; j++) { symbol = accessing_symbol[sp->shift[j]]; if (nullable[symbol]) edge[nedges++] = map_goto(stateno, symbol); } if (nedges) { reads[i] = rp = NEW2(nedges + 1, short); for (j = 0; j < nedges; j++) rp[j] = edge[j]; rp[nedges] = -1; nedges = 0; } } rowp += tokensetsize; } SETBIT(F, 0); digraph(reads); for (i = 0; i < ngotos; i++) { if (reads[i]) FREE(reads[i]); } FREE(reads); FREE(edge); } static void build_relations() { int i; int j; int k; short *rulep; short *rp; shifts *sp; int length; int nedges; int done1; int state1; int stateno; int symbol1; int symbol2; short *shortp; short *edge; short *states; short **new_includes; includes = NEW2(ngotos, short *); edge = NEW2(ngotos + 1, short); states = NEW2(maxrhs + 1, short); for (i = 0; i < ngotos; i++) { nedges = 0; state1 = from_state[i]; symbol1 = accessing_symbol[to_state[i]]; for (rulep = derives[symbol1]; *rulep >= 0; rulep++) { length = 1; states[0] = state1; stateno = state1; for (rp = ritem + rrhs[*rulep]; *rp >= 0; rp++) { symbol2 = *rp; sp = shift_table[stateno]; k = sp->nshifts; for (j = 0; j < k; j++) { stateno = sp->shift[j]; if (accessing_symbol[stateno] == symbol2) break; } states[length++] = stateno; } add_lookback_edge(stateno, *rulep, i); length--; done1 = 0; while (!done1) { done1 = 1; rp--; if (ISVAR(*rp)) { stateno = states[--length]; edge[nedges++] = map_goto(stateno, *rp); if (nullable[*rp] && length > 0) done1 = 0; } } } if (nedges) { includes[i] = shortp = NEW2(nedges + 1, short); for (j = 0; j < nedges; j++) shortp[j] = edge[j]; shortp[nedges] = -1; } } new_includes = transpose(includes, ngotos); for (i = 0; i < ngotos; i++) if (includes[i]) FREE(includes[i]); FREE(includes); includes = new_includes; FREE(edge); FREE(states); } static void add_lookback_edge(stateno, ruleno, gotono) int stateno, ruleno, gotono; { int i, 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; } assert(found); sp = NEW(shorts); sp->next = lookback[i]; sp->value = gotono; lookback[i] = sp; } static short ** transpose(R, n) short **R; int n; { short **new_R; short **temp_R; short *nedges; short *sp; int i; int k; nedges = NEW2(n, short); for (i = 0; i < n; i++) { sp = R[i]; if (sp) { while (*sp >= 0) nedges[*sp++]++; } } new_R = NEW2(n, short *); temp_R = NEW2(n, short *); 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(nedges); for (i = 0; i < n; i++) { sp = R[i]; if (sp) { while (*sp >= 0) *temp_R[*sp++]++ = i; } } FREE(temp_R); return (new_R); } static void compute_FOLLOWS() { digraph(includes); } static void compute_lookaheads() { int i, n; unsigned *fp1, *fp2, *fp3; shorts *sp, *next; unsigned *rowp; rowp = LA; n = lookaheads[nstates]; for (i = 0; i < n; i++) { fp3 = rowp + tokensetsize; for (sp = lookback[i]; sp; sp = sp->next) { fp1 = rowp; fp2 = F + tokensetsize * sp->value; while (fp1 < fp3) *fp1++ |= *fp2++; } rowp = fp3; } for (i = 0; i < n; i++) for (sp = lookback[i]; sp; sp = next) { next = sp->next; FREE(sp); } FREE(lookback); FREE(F); } static void digraph(relation) short **relation; { int i; infinity = ngotos + 2; INDEX = NEW2(ngotos + 1, short); VERTICES = NEW2(ngotos + 1, short); top = 0; for (i = 0; i < ngotos; i++) INDEX[i] = 0; for (i = 0; i < ngotos; i++) { if (INDEX[i] == 0 && relation[i]) traverse(i, relation); } FREE(INDEX); FREE(VERTICES); } static void traverse(i, R) int i; short **R; { 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, R); 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++; } } }