660 lines
11 KiB
C
660 lines
11 KiB
C
/* $NetBSD: lalr.c,v 1.5 2011/09/10 21:29:04 christos Exp $ */
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/* Id: lalr.c,v 1.9 2009/10/27 09:49:27 tom Exp */
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#include "defs.h"
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: lalr.c,v 1.5 2011/09/10 21:29:04 christos Exp $");
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typedef struct shorts
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{
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struct shorts *next;
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Value_t value;
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}
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shorts;
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static Value_t map_goto(int state, int symbol);
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static Value_t **transpose(Value_t ** R, int n);
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static void add_lookback_edge(int stateno, int ruleno, int gotono);
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static void build_relations(void);
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static void compute_FOLLOWS(void);
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static void compute_lookaheads(void);
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static void digraph(Value_t ** relation);
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static void initialize_F(void);
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static void initialize_LA(void);
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static void set_accessing_symbol(void);
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static void set_goto_map(void);
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static void set_maxrhs(void);
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static void set_reduction_table(void);
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static void set_shift_table(void);
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static void set_state_table(void);
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static void traverse(int i);
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static int tokensetsize;
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Value_t *lookaheads;
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Value_t *LAruleno;
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unsigned *LA;
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Value_t *accessing_symbol;
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core **state_table;
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shifts **shift_table;
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reductions **reduction_table;
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Value_t *goto_map;
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Value_t *from_state;
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Value_t *to_state;
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static Value_t infinity;
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static int maxrhs;
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static int ngotos;
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static unsigned *F;
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static Value_t **includes;
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static shorts **lookback;
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static Value_t **R;
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static Value_t *INDEX;
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static Value_t *VERTICES;
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static Value_t top;
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void
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lalr(void)
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{
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tokensetsize = WORDSIZE(ntokens);
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set_state_table();
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set_accessing_symbol();
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set_shift_table();
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set_reduction_table();
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set_maxrhs();
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initialize_LA();
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set_goto_map();
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initialize_F();
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build_relations();
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compute_FOLLOWS();
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compute_lookaheads();
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}
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static void
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set_state_table(void)
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{
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core *sp;
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state_table = NEW2(nstates, core *);
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for (sp = first_state; sp; sp = sp->next)
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state_table[sp->number] = sp;
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}
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static void
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set_accessing_symbol(void)
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{
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core *sp;
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accessing_symbol = NEW2(nstates, Value_t);
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for (sp = first_state; sp; sp = sp->next)
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accessing_symbol[sp->number] = sp->accessing_symbol;
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}
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static void
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set_shift_table(void)
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{
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shifts *sp;
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shift_table = NEW2(nstates, shifts *);
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for (sp = first_shift; sp; sp = sp->next)
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shift_table[sp->number] = sp;
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}
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static void
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set_reduction_table(void)
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{
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reductions *rp;
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reduction_table = NEW2(nstates, reductions *);
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for (rp = first_reduction; rp; rp = rp->next)
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reduction_table[rp->number] = rp;
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}
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static void
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set_maxrhs(void)
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{
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Value_t *itemp;
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Value_t *item_end;
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int length;
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int max;
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length = 0;
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max = 0;
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item_end = ritem + nitems;
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for (itemp = ritem; itemp < item_end; itemp++)
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{
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if (*itemp >= 0)
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{
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length++;
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}
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else
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{
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if (length > max)
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max = length;
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length = 0;
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}
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}
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maxrhs = max;
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}
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static void
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initialize_LA(void)
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{
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int i, j, k;
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reductions *rp;
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lookaheads = NEW2(nstates + 1, Value_t);
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k = 0;
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for (i = 0; i < nstates; i++)
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{
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lookaheads[i] = (Value_t) k;
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rp = reduction_table[i];
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if (rp)
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k += rp->nreds;
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}
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lookaheads[nstates] = (Value_t) k;
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LA = NEW2(k * tokensetsize, unsigned);
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LAruleno = NEW2(k, Value_t);
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lookback = NEW2(k, shorts *);
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k = 0;
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for (i = 0; i < nstates; i++)
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{
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rp = reduction_table[i];
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if (rp)
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{
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for (j = 0; j < rp->nreds; j++)
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{
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LAruleno[k] = rp->rules[j];
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k++;
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}
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}
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}
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}
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static void
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set_goto_map(void)
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{
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shifts *sp;
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int i;
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int symbol;
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int k;
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Value_t *temp_map;
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Value_t state2;
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Value_t state1;
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goto_map = NEW2(nvars + 1, Value_t) - ntokens;
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temp_map = NEW2(nvars + 1, Value_t) - ntokens;
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ngotos = 0;
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for (sp = first_shift; sp; sp = sp->next)
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{
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for (i = sp->nshifts - 1; i >= 0; i--)
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{
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symbol = accessing_symbol[sp->shift[i]];
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if (ISTOKEN(symbol))
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break;
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if (ngotos == MAXSHORT)
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fatal("too many gotos");
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ngotos++;
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goto_map[symbol]++;
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}
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}
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k = 0;
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for (i = ntokens; i < nsyms; i++)
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{
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temp_map[i] = (Value_t) k;
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k += goto_map[i];
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}
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for (i = ntokens; i < nsyms; i++)
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goto_map[i] = temp_map[i];
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goto_map[nsyms] = (Value_t) ngotos;
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temp_map[nsyms] = (Value_t) ngotos;
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from_state = NEW2(ngotos, Value_t);
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to_state = NEW2(ngotos, Value_t);
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for (sp = first_shift; sp; sp = sp->next)
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{
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state1 = sp->number;
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for (i = sp->nshifts - 1; i >= 0; i--)
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{
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state2 = sp->shift[i];
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symbol = accessing_symbol[state2];
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if (ISTOKEN(symbol))
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break;
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k = temp_map[symbol]++;
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from_state[k] = state1;
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to_state[k] = state2;
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}
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}
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FREE(temp_map + ntokens);
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}
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/* Map_goto maps a state/symbol pair into its numeric representation. */
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static Value_t
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map_goto(int state, int symbol)
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{
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int high;
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int low;
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int middle;
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int s;
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low = goto_map[symbol];
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high = goto_map[symbol + 1];
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for (;;)
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{
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assert(low <= high);
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middle = (low + high) >> 1;
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s = from_state[middle];
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if (s == state)
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return (Value_t) (middle);
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else if (s < state)
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low = middle + 1;
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else
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high = middle - 1;
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}
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}
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static void
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initialize_F(void)
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{
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int i;
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int j;
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int k;
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shifts *sp;
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Value_t *edge;
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unsigned *rowp;
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Value_t *rp;
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Value_t **reads;
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int nedges;
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int stateno;
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int symbol;
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int nwords;
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nwords = ngotos * tokensetsize;
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F = NEW2(nwords, unsigned);
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reads = NEW2(ngotos, Value_t *);
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edge = NEW2(ngotos + 1, Value_t);
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nedges = 0;
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rowp = F;
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for (i = 0; i < ngotos; i++)
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{
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stateno = to_state[i];
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sp = shift_table[stateno];
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if (sp)
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{
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k = sp->nshifts;
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for (j = 0; j < k; j++)
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{
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symbol = accessing_symbol[sp->shift[j]];
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if (ISVAR(symbol))
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break;
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SETBIT(rowp, symbol);
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}
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for (; j < k; j++)
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{
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symbol = accessing_symbol[sp->shift[j]];
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if (nullable[symbol])
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edge[nedges++] = map_goto(stateno, symbol);
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}
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if (nedges)
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{
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reads[i] = rp = NEW2(nedges + 1, Value_t);
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for (j = 0; j < nedges; j++)
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rp[j] = edge[j];
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rp[nedges] = -1;
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nedges = 0;
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}
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}
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rowp += tokensetsize;
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}
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SETBIT(F, 0);
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digraph(reads);
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for (i = 0; i < ngotos; i++)
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{
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if (reads[i])
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FREE(reads[i]);
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}
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FREE(reads);
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FREE(edge);
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}
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static void
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build_relations(void)
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{
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int i;
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int j;
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int k;
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Value_t *rulep;
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Value_t *rp;
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shifts *sp;
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int length;
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int nedges;
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int done_flag;
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Value_t state1;
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Value_t stateno;
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int symbol1;
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int symbol2;
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Value_t *shortp;
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Value_t *edge;
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Value_t *states;
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Value_t **new_includes;
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includes = NEW2(ngotos, Value_t *);
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edge = NEW2(ngotos + 1, Value_t);
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states = NEW2(maxrhs + 1, Value_t);
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for (i = 0; i < ngotos; i++)
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{
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nedges = 0;
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state1 = from_state[i];
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symbol1 = accessing_symbol[to_state[i]];
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for (rulep = derives[symbol1]; *rulep >= 0; rulep++)
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{
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length = 1;
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states[0] = state1;
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stateno = state1;
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for (rp = ritem + rrhs[*rulep]; *rp >= 0; rp++)
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{
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symbol2 = *rp;
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sp = shift_table[stateno];
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k = sp->nshifts;
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for (j = 0; j < k; j++)
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{
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stateno = sp->shift[j];
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if (accessing_symbol[stateno] == symbol2)
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break;
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}
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states[length++] = stateno;
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}
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add_lookback_edge(stateno, *rulep, i);
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length--;
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done_flag = 0;
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while (!done_flag)
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{
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done_flag = 1;
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rp--;
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if (ISVAR(*rp))
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{
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stateno = states[--length];
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edge[nedges++] = map_goto(stateno, *rp);
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if (nullable[*rp] && length > 0)
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done_flag = 0;
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}
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}
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}
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if (nedges)
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{
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includes[i] = shortp = NEW2(nedges + 1, Value_t);
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for (j = 0; j < nedges; j++)
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shortp[j] = edge[j];
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shortp[nedges] = -1;
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}
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}
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new_includes = transpose(includes, ngotos);
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for (i = 0; i < ngotos; i++)
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if (includes[i])
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FREE(includes[i]);
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FREE(includes);
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includes = new_includes;
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FREE(edge);
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FREE(states);
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}
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static void
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add_lookback_edge(int stateno, int ruleno, int gotono)
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{
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int i, k;
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int found;
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shorts *sp;
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i = lookaheads[stateno];
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k = lookaheads[stateno + 1];
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found = 0;
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while (!found && i < k)
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{
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if (LAruleno[i] == ruleno)
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found = 1;
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else
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++i;
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}
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assert(found);
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sp = NEW(shorts);
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sp->next = lookback[i];
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sp->value = (Value_t) gotono;
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lookback[i] = sp;
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}
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static Value_t **
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transpose(Value_t ** R2, int n)
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{
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Value_t **new_R;
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Value_t **temp_R;
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Value_t *nedges;
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Value_t *sp;
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int i;
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int k;
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nedges = NEW2(n, Value_t);
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for (i = 0; i < n; i++)
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{
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sp = R2[i];
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if (sp)
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{
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while (*sp >= 0)
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nedges[*sp++]++;
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}
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}
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new_R = NEW2(n, Value_t *);
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temp_R = NEW2(n, Value_t *);
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for (i = 0; i < n; i++)
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{
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k = nedges[i];
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if (k > 0)
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{
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sp = NEW2(k + 1, Value_t);
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new_R[i] = sp;
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temp_R[i] = sp;
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sp[k] = -1;
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}
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}
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FREE(nedges);
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for (i = 0; i < n; i++)
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{
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sp = R2[i];
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if (sp)
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{
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while (*sp >= 0)
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*temp_R[*sp++]++ = (Value_t) i;
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}
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}
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FREE(temp_R);
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return (new_R);
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}
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static void
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compute_FOLLOWS(void)
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{
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digraph(includes);
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}
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static void
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compute_lookaheads(void)
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{
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int i, n;
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unsigned *fp1, *fp2, *fp3;
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shorts *sp, *next;
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unsigned *rowp;
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rowp = LA;
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n = lookaheads[nstates];
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for (i = 0; i < n; i++)
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{
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fp3 = rowp + tokensetsize;
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for (sp = lookback[i]; sp; sp = sp->next)
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{
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fp1 = rowp;
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fp2 = F + tokensetsize * sp->value;
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while (fp1 < fp3)
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*fp1++ |= *fp2++;
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}
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rowp = fp3;
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}
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for (i = 0; i < n; i++)
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for (sp = lookback[i]; sp; sp = next)
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{
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next = sp->next;
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FREE(sp);
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}
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FREE(lookback);
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FREE(F);
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}
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static void
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digraph(Value_t ** relation)
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{
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int i;
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infinity = (Value_t) (ngotos + 2);
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INDEX = NEW2(ngotos + 1, Value_t);
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VERTICES = NEW2(ngotos + 1, Value_t);
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top = 0;
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R = relation;
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for (i = 0; i < ngotos; i++)
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INDEX[i] = 0;
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for (i = 0; i < ngotos; i++)
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{
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if (INDEX[i] == 0 && R[i])
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traverse(i);
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}
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FREE(INDEX);
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FREE(VERTICES);
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}
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static void
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traverse(int i)
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{
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unsigned *fp1;
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unsigned *fp2;
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unsigned *fp3;
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int j;
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Value_t *rp;
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Value_t height;
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unsigned *base;
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VERTICES[++top] = (Value_t) i;
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INDEX[i] = height = top;
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base = F + i * tokensetsize;
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fp3 = base + tokensetsize;
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rp = R[i];
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if (rp)
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{
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while ((j = *rp++) >= 0)
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{
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if (INDEX[j] == 0)
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traverse(j);
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if (INDEX[i] > INDEX[j])
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INDEX[i] = INDEX[j];
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fp1 = base;
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fp2 = F + j * tokensetsize;
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|
|
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++;
|
|
}
|
|
}
|
|
}
|
|
|
|
#ifdef NO_LEAKS
|
|
void
|
|
lalr_leaks(void)
|
|
{
|
|
int i;
|
|
|
|
if (includes != 0)
|
|
{
|
|
for (i = 0; i < ngotos; i++)
|
|
{
|
|
free(includes[i]);
|
|
}
|
|
DO_FREE(includes);
|
|
}
|
|
}
|
|
#endif
|