/* Compute look-ahead criteria for bison,
- Copyright (C) 1984, 1986, 1989 Free Software Foundation, Inc.
+ Copyright 1984, 1986, 1989, 2000, 2001 Free Software Foundation, Inc.
-This file is part of Bison, the GNU Compiler Compiler.
+ This file is part of Bison, the GNU Compiler Compiler.
-Bison is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2, or (at your option)
-any later version.
+ Bison is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
-Bison is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
+ Bison is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
-You should have received a copy of the GNU General Public License
-along with Bison; see the file COPYING. If not, write to
-the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
+ You should have received a copy of the GNU General Public License
+ along with Bison; see the file COPYING. If not, write to
+ the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
-/* Compute how to make the finite state machine deterministic;
- find which rules need lookahead in each state, and which lookahead tokens they accept.
+/* Compute how to make the finite state machine deterministic; find
+ which rules need lookahead in each state, and which lookahead
+ tokens they accept. */
-lalr(), the entry point, builds these data structures:
-
-goto_map, from_state and to_state
- record each shift transition which accepts a variable (a nonterminal).
-ngotos is the number of such transitions.
-from_state[t] is the state number which a transition leads from
-and to_state[t] is the state number it leads to.
-All the transitions that accept a particular variable are grouped together and
-goto_map[i - ntokens] is the index in from_state and to_state of the first of them.
-
-consistent[s] is nonzero if no lookahead is needed to decide what to do in state s.
-
-LAruleno is a vector which records the rules that need lookahead in various states.
-The elements of LAruleno that apply to state s are those from
- lookaheads[s] through lookaheads[s+1]-1.
-Each element of LAruleno is a rule number.
-
-If lr is the length of LAruleno, then a number from 0 to lr-1
-can specify both a rule and a state where the rule might be applied.
-
-LA is a lr by ntokens matrix of bits.
-LA[l, i] is 1 if the rule LAruleno[l] is applicable in the appropriate state
- when the next token is symbol i.
-If LA[l, i] and LA[l, j] are both 1 for i != j, it is a conflict.
-*/
-
-#include <stdio.h>
#include "system.h"
-#include "machine.h"
+#include "bitset.h"
+#include "reader.h"
#include "types.h"
-#include "state.h"
-#include "alloc.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"
-
-extern short **derives;
-extern char *nullable;
-
+/* 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;
-short *goto_map;
-short *from_state;
-short *to_state;
-
-short **transpose();
-void set_state_table();
-void set_accessing_symbol();
-void set_shift_table();
-void set_reduction_table();
-void set_maxrhs();
-void initialize_LA();
-void set_goto_map();
-void initialize_F();
-void build_relations();
-void add_lookback_edge();
-void compute_FOLLOWS();
-void compute_lookaheads();
-void digraph();
-void traverse();
-
-extern void toomany();
-extern void berror();
+short *LAruleno = NULL;
+bitset *LA = NULL;
+size_t nLA;
-static int infinity;
-static int maxrhs;
static int ngotos;
-static unsigned *F;
+short *goto_map = NULL;
+short *from_state = NULL;
+short *to_state = NULL;
+
+/* And for the famous F variable, which name is so descriptive that a
+ comment is hardly needed. <grin>. */
+static bitset *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;
-
-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();
-}
-
-
-void
-set_state_table()
+static void
+traverse (int i)
{
- register core *sp;
-
- state_table = NEW2(nstates, core *);
-
- for (sp = first_state; sp; sp = sp->next)
- state_table[sp->number] = sp;
-}
-
+ int j;
+ int height;
-void
-set_accessing_symbol()
-{
- register core *sp;
+ VERTICES[++top] = i;
+ INDEX[i] = height = top;
- accessing_symbol = NEW2(nstates, short);
+ if (R[i])
+ for (j = 0; R[i][j] >= 0; ++j)
+ {
+ if (INDEX[R[i][j]] == 0)
+ traverse (R[i][j]);
- for (sp = first_state; sp; sp = sp->next)
- accessing_symbol[sp->number] = sp->accessing_symbol;
-}
+ if (INDEX[i] > INDEX[R[i][j]])
+ INDEX[i] = INDEX[R[i][j]];
+ bitset_or (F[i], F[i], F[R[i][j]]);
+ }
-void
-set_shift_table()
-{
- register shifts *sp;
+ if (INDEX[i] == height)
+ for (;;)
+ {
+ j = VERTICES[top--];
+ INDEX[j] = infinity;
- shift_table = NEW2(nstates, shifts *);
+ if (i == j)
+ break;
- for (sp = first_shift; sp; sp = sp->next)
- shift_table[sp->number] = sp;
+ bitset_copy (F[j], F[i]);
+ }
}
-void
-set_reduction_table()
+static void
+digraph (short **relation)
{
- register reductions *rp;
+ int i;
- reduction_table = NEW2(nstates, reductions *);
-
- for (rp = first_reduction; rp; rp = rp->next)
- reduction_table[rp->number] = rp;
-}
+ infinity = ngotos + 2;
+ INDEX = XCALLOC (short, ngotos + 1);
+ VERTICES = XCALLOC (short, ngotos + 1);
+ top = 0;
+ R = relation;
-void
-set_maxrhs()
-{
- register short *itemp;
- register int length;
- register int max;
+ for (i = 0; i < ngotos; i++)
+ INDEX[i] = 0;
- length = 0;
- max = 0;
- for (itemp = ritem; *itemp; itemp++)
- {
- if (*itemp > 0)
- {
- length++;
- }
- else
- {
- if (length > max) max = length;
- length = 0;
- }
- }
+ for (i = 0; i < ngotos; i++)
+ if (INDEX[i] == 0 && R[i])
+ traverse (i);
- maxrhs = max;
+ XFREE (INDEX);
+ XFREE (VERTICES);
}
-void
-initialize_LA()
+static void
+initialize_LA (void)
{
- register int i;
- register int j;
- register int count;
- register reductions *rp;
- register shifts *sp;
- register short *np;
+ size_t i;
+ int j;
+ short *np;
- consistent = NEW2(nstates, char);
- lookaheads = NEW2(nstates + 1, short);
+ /* Avoid having to special case 0. */
+ if (!nLA)
+ nLA = 1;
- count = 0;
- for (i = 0; i < nstates; i++)
+ LA = XCALLOC (bitset, nLA);
+ for (i = 0; i < nLA; ++i)
{
- register int k;
-
- 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 = NEW2(1 * tokensetsize, unsigned);
- LAruleno = NEW2(1, short);
- lookback = NEW2(1, shorts *);
- }
- else
- {
- LA = NEW2(count * tokensetsize, unsigned);
- LAruleno = NEW2(count, short);
- lookback = NEW2(count, shorts *);
+ LA[i] = bitset_create (ntokens, BITSET_FIXED);
+ bitset_zero (LA[i]);
}
+ 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];
}
-void
-set_goto_map()
+static void
+set_goto_map (void)
{
- register shifts *sp;
- register int i;
- register int symbol;
- register int k;
- register short *temp_map;
- register int state2;
- register int state1;
+ size_t state;
+ int i;
+ short *temp_map;
- goto_map = NEW2(nvars + 1, short) - ntokens;
- temp_map = NEW2(nvars + 1, short) - ntokens;
+ 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)
- toomany(_("gotos"));
+ 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 = NEW2(ngotos, short);
- to_state = NEW2(ngotos, short);
+ 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];
}
}
- FREE(temp_map + ntokens);
+ XFREE (temp_map + ntokens);
}
-/* Map_goto maps a state/symbol pair into its numeric representation. */
+/*----------------------------------------------------------.
+| Map a state/symbol pair into its numeric representation. |
+`----------------------------------------------------------*/
-int
-map_goto(state, symbol)
-int state;
-int symbol;
+static int
+map_goto (int state, int symbol)
{
- register int high;
- register int low;
- register int middle;
- register int s;
+ int high;
+ int low;
+ int middle;
+ int s;
low = goto_map[symbol];
high = goto_map[symbol + 1] - 1;
middle = (low + high) / 2;
s = from_state[middle];
if (s == state)
- return (middle);
+ return middle;
else if (s < state)
low = middle + 1;
else
high = middle - 1;
}
- berror("map_goto");
-/* NOTREACHED */
+ assert (0);
+ /* NOTREACHED */
return 0;
}
-void
-initialize_F()
+static void
+initialize_F (void)
{
- register int i;
- register int j;
- register int k;
- register shifts *sp;
- register short *edge;
- register unsigned *rowp;
- register short *rp;
- register short **reads;
- register int nedges;
- register int stateno;
- register int symbol;
- register 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];
+ short **reads = XCALLOC (short *, ngotos);
+ short *edge = XCALLOC (short, ngotos + 1);
+ int nedges = 0;
- if (sp)
- {
- k = sp->nshifts;
-
- for (j = 0; j < k; j++)
- {
- symbol = accessing_symbol[sp->shifts[j]];
- if (ISVAR(symbol))
- break;
- SETBIT(rowp, symbol);
- }
-
- for (; j < k; j++)
- {
- symbol = accessing_symbol[sp->shifts[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;
- }
+ int i;
- digraph(reads);
-
- for (i = 0; i < ngotos; i++)
+ F = XCALLOC (bitset, ngotos);
+ for (i = 0; i < ngotos; ++i)
{
- if (reads[i])
- FREE(reads[i]);
+ F[i] = bitset_create (ntokens, BITSET_FIXED);
+ bitset_zero (F[i]);
}
- FREE(reads);
- FREE(edge);
-}
-
-
-void
-build_relations()
-{
- register int i;
- register int j;
- register int k;
- register short *rulep;
- register short *rp;
- register shifts *sp;
- register int length;
- register int nedges;
- register int done;
- register int state1;
- register int stateno;
- register int symbol1;
- register int symbol2;
- register short *shortp;
- register short *edge;
- register short *states;
- register 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]];
+ int stateno = to_state[i];
+ shifts *sp = states[stateno]->shifts;
- for (rulep = derives[symbol1]; *rulep > 0; rulep++)
- {
- length = 1;
- states[0] = state1;
- stateno = state1;
+ int j;
+ for (j = 0; j < sp->nshifts && SHIFT_IS_SHIFT (sp, j); j++)
+ bitset_set (F[i], SHIFT_SYMBOL (sp, j));
- 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->shifts[j];
- if (accessing_symbol[stateno] == symbol2) break;
- }
-
- states[length++] = stateno;
- }
-
- if (!consistent[stateno])
- add_lookback_edge(stateno, *rulep, i);
-
- length--;
- done = 0;
- while (!done)
- {
- done = 1;
- rp--;
- /* JF added rp>=ritem && I hope to god its right! */
- if (rp>=ritem && ISVAR(*rp))
- {
- stateno = states[--length];
- edge[nedges++] = map_goto(stateno, *rp);
- if (nullable[*rp]) done = 0;
- }
- }
+ for (; j < sp->nshifts; j++)
+ {
+ int symbol = SHIFT_SYMBOL (sp, j);
+ if (nullable[symbol])
+ edge[nedges++] = map_goto (stateno, symbol);
}
if (nedges)
{
- includes[i] = shortp = NEW2(nedges + 1, short);
- for (j = 0; j < nedges; j++)
- shortp[j] = edge[j];
- shortp[nedges] = -1;
+ reads[i] = XCALLOC (short, nedges + 1);
+ shortcpy (reads[i], edge, nedges);
+ reads[i][nedges] = -1;
+ nedges = 0;
}
}
- new_includes = transpose(includes, ngotos);
+ digraph (reads);
for (i = 0; i < ngotos; i++)
- if (includes[i])
- FREE(includes[i]);
-
- FREE(includes);
+ XFREE (reads[i]);
- includes = new_includes;
-
- FREE(edge);
- FREE(states);
+ XFREE (reads);
+ XFREE (edge);
}
-void
-add_lookback_edge(stateno, ruleno, gotono)
-int stateno;
-int ruleno;
-int gotono;
+static void
+add_lookback_edge (state_t *state, int ruleno, int gotono)
{
- register int i;
- register int k;
- register int found;
- register shorts *sp;
-
- i = lookaheads[stateno];
- k = lookaheads[stateno + 1];
- found = 0;
- while (!found && i < k)
- {
- if (LAruleno[i] == ruleno)
- found = 1;
- else
- i++;
- }
+ int i;
+ shorts *sp;
- if (found == 0)
- berror("add_lookback_edge");
+ for (i = 0; i < state->nlookaheads; ++i)
+ if (LAruleno[state->lookaheadsp + i] == ruleno)
+ break;
- sp = NEW(shorts);
- sp->next = lookback[i];
+ assert (LAruleno[state->lookaheadsp + i] == ruleno);
+
+ sp = XCALLOC (shorts, 1);
+ sp->next = lookback[state->lookaheadsp + i];
sp->value = gotono;
- lookback[i] = sp;
+ lookback[state->lookaheadsp + i] = sp;
}
-
-short **
-transpose(R_arg, n)
-short **R_arg;
-int n;
+static void
+matrix_print (FILE *out, short **matrix, int n)
{
- register short **new_R;
- register short **temp_R;
- register short *nedges;
- register short *sp;
- register int i;
- register int k;
+ int i, j;
- nedges = NEW2(n, short);
+ 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);
+}
- for (i = 0; i < n; i++)
+/*-------------------------------------------------------------------.
+| 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)
+{
+ /* 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 = NEW2(n, short *);
- temp_R = NEW2(n, short *);
+ /* 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 = NEW2(k + 1, short);
- new_R[i] = sp;
- temp_R[i] = sp;
- sp[k] = -1;
+ *end_R[R_arg[i][j]] = i;
+ ++end_R[R_arg[i][j]];
}
- }
- FREE(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);
}
- FREE(temp_R);
-
- return (new_R);
+ return new_R;
}
-void
-compute_FOLLOWS()
+static void
+build_relations (void)
{
- register int i;
+ short *edge = XCALLOC (short, ngotos + 1);
+ short *states1 = XCALLOC (short, ritem_longest_rhs () + 1);
+ int i;
- digraph(includes);
+ includes = XCALLOC (short *, ngotos);
for (i = 0; i < ngotos; i++)
{
- if (includes[i]) FREE(includes[i]);
- }
+ int nedges = 0;
+ int symbol1 = states[to_state[i]]->accessing_symbol;
+ short *rulep;
- FREE(includes);
-}
+ for (rulep = derives[symbol1]; *rulep > 0; rulep++)
+ {
+ int done;
+ int length = 1;
+ short *rp;
+ state_t *state = states[from_state[i]];
+ states1[0] = state->number;
+ for (rp = &ritem[rules[*rulep].rhs]; *rp >= 0; rp++)
+ {
+ shifts *sp = state->shifts;
+ int j;
+ for (j = 0; j < sp->nshifts; j++)
+ {
+ state = states[sp->shifts[j]];
+ if (state->accessing_symbol == *rp)
+ break;
+ }
-void
-compute_lookaheads()
-{
- register int i;
- register int n;
- register unsigned *fp1;
- register unsigned *fp2;
- register unsigned *fp3;
- register shorts *sp;
- register unsigned *rowp;
-/* register short *rulep; JF unused */
-/* register int count; JF unused */
- register shorts *sptmp;/* JF */
-
- 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++;
+ states1[length++] = state->number;
+ }
+
+ if (!state->consistent)
+ add_lookback_edge (state, *rulep, i);
+
+ length--;
+ done = 0;
+ while (!done)
+ {
+ done = 1;
+ rp--;
+ /* JF added rp>=ritem && I hope to god its right! */
+ if (rp >= ritem && ISVAR (*rp))
+ {
+ edge[nedges++] = map_goto (states1[--length], *rp);
+ if (nullable[*rp])
+ done = 0;
+ }
+ }
}
- rowp = fp3;
+ if (nedges)
+ {
+ int j;
+ includes[i] = XCALLOC (short, nedges + 1);
+ for (j = 0; j < nedges; j++)
+ includes[i][j] = edge[j];
+ includes[i][nedges] = -1;
+ }
}
- for (i = 0; i < n; i++)
- {/* JF removed ref to freed storage */
- for (sp = lookback[i]; sp; sp = sptmp) {
- sptmp=sp->next;
- FREE(sp);
- }
- }
+ XFREE (edge);
+ XFREE (states1);
- FREE(lookback);
- FREE(F);
+ includes = transpose (includes, ngotos);
}
-void
-digraph(relation)
-short **relation;
-{
- register int i;
-
- infinity = ngotos + 2;
- INDEX = NEW2(ngotos + 1, short);
- VERTICES = NEW2(ngotos + 1, short);
- top = 0;
- R = relation;
+static void
+compute_FOLLOWS (void)
+{
+ int i;
- for (i = 0; i < ngotos; i++)
- INDEX[i] = 0;
+ digraph (includes);
for (i = 0; i < ngotos; i++)
- {
- if (INDEX[i] == 0 && R[i])
- traverse(i);
- }
+ XFREE (includes[i]);
- FREE(INDEX);
- FREE(VERTICES);
+ XFREE (includes);
}
-void
-traverse(i)
-register int i;
+static void
+compute_lookaheads (void)
{
- register unsigned *fp1;
- register unsigned *fp2;
- register unsigned *fp3;
- register int j;
- register short *rp;
+ size_t i;
+ shorts *sp;
- int height;
- unsigned *base;
-
- VERTICES[++top] = i;
- INDEX[i] = height = top;
+ for (i = 0; i < nLA; i++)
+ for (sp = lookback[i]; sp; sp = sp->next)
+ bitset_or (LA[i], LA[i], F[sp->value]);
- base = F + i * tokensetsize;
- fp3 = base + tokensetsize;
-
- rp = R[i];
- if (rp)
- {
- while ((j = *rp++) >= 0)
- {
- if (INDEX[j] == 0)
- traverse(j);
+ /* Free LOOKBACK. */
+ for (i = 0; i < nLA; i++)
+ LIST_FREE (shorts, lookback[i]);
- if (INDEX[i] > INDEX[j])
- INDEX[i] = INDEX[j];
+ XFREE (lookback);
+ for (i = 0; i < (unsigned) ngotos; ++i)
+ bitset_free (F[i]);
+ XFREE (F);
+}
- fp1 = base;
- fp2 = F + j * tokensetsize;
- while (fp1 < fp3)
- *fp1++ |= *fp2++;
- }
- }
+/*--------------------------------------.
+| Initializing the lookaheads members. |
+`--------------------------------------*/
- if (INDEX[i] == height)
+static void
+initialize_lookaheads (void)
+{
+ size_t i;
+ nLA = 0;
+ for (i = 0; i < nstates; i++)
{
- for (;;)
- {
- j = VERTICES[top--];
- INDEX[j] = infinity;
+ 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;
- if (i == j)
+ for (k = 0; k < sp->nshifts; k++)
+ if (SHIFT_IS_ERROR (sp, k))
+ {
+ states[i]->consistent = 0;
break;
+ }
- fp1 = base;
- fp2 = F + j * tokensetsize;
+ states[i]->nlookaheads = nlookaheads;
+ states[i]->lookaheadsp = nLA;
+ nLA += nlookaheads;
+ }
+}
- while (fp1 < fp3)
- *fp2++ = *fp1++;
- }
+
+/*---------------------------------------.
+| Output the lookaheads for each state. |
+`---------------------------------------*/
+
+static void
+lookaheads_print (FILE *out)
+{
+ size_t i;
+ int 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 (bitset_test (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);
+
+ initialize_lookaheads ();
+ initialize_LA ();
+ set_goto_map ();
+ initialize_F ();
+ build_relations ();
+ compute_FOLLOWS ();
+ compute_lookaheads ();
+
+ if (trace_flag)
+ lookaheads_print (stderr);
}
projects / bison.git / blobdiff