/* Compute look-ahead criteria for bison,
- Copyright 1984, 1986, 1989, 2000, 2001 Free Software Foundation, Inc.
+ Copyright (C) 1984, 1986, 1989, 2000, 2001, 2002
+ Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
tokens they accept. */
#include "system.h"
+#include "bitset.h"
+#include "bitsetv.h"
+#include "relation.h"
+#include "quotearg.h"
+#include "symtab.h"
+#include "gram.h"
+#include "reader.h"
#include "types.h"
#include "LR0.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 **state_table = NULL;
-
-int tokensetsize;
-short *LAruleno;
-unsigned *LA;
+rule_t **LArule = NULL;
+bitsetv LA = NULL;
size_t nLA;
static int ngotos;
-short *goto_map;
-short *from_state;
-short *to_state;
+short *goto_map = NULL;
+state_number_t *from_state = NULL;
+state_number_t *to_state = NULL;
/* And for the famous F variable, which name is so descriptive that a
comment is hardly needed. <grin>. */
-static unsigned *F = NULL;
-#define F(Rule) (F + (Rule) * tokensetsize)
+static bitsetv 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)
-{
- int j;
- size_t k;
- int height;
- size_t size = F (i + 1) - F(i);
-
- VERTICES[++top] = i;
- INDEX[i] = height = top;
-
- if (R[i])
- for (j = 0; R[i][j] >= 0; ++j)
- {
- if (INDEX[R[i][j]] == 0)
- traverse (R[i][j]);
-
- if (INDEX[i] > INDEX[R[i][j]])
- INDEX[i] = INDEX[R[i][j]];
-
- 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 (k = 0; k < size; ++k)
- F (j)[k] = F (i)[k];
- }
-}
-
-
-static void
-digraph (short **relation)
-{
- int i;
-
- infinity = ngotos + 2;
- INDEX = XCALLOC (short, ngotos + 1);
- VERTICES = XCALLOC (short, ngotos + 1);
- top = 0;
-
- R = relation;
-
- for (i = 0; i < ngotos; i++)
- INDEX[i] = 0;
-
- for (i = 0; i < ngotos; i++)
- if (INDEX[i] == 0 && R[i])
- traverse (i);
-
- XFREE (INDEX);
- XFREE (VERTICES);
-}
static void
initialize_LA (void)
{
- int i;
+ state_number_t i;
int j;
- short *np;
+ rule_t **np;
/* Avoid having to special case 0. */
if (!nLA)
nLA = 1;
- LA = XCALLOC (unsigned, nLA * tokensetsize);
- LAruleno = XCALLOC (short, nLA);
+ LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
+ LArule = XCALLOC (rule_t *, nLA);
lookback = XCALLOC (shorts *, nLA);
- np = LAruleno;
+ np = LArule;
for (i = 0; i < nstates; i++)
- if (!state_table[i]->consistent)
- for (j = 0; j < state_table[i]->reductions->nreds; j++)
- *np++ = state_table[i]->reductions->rules[j];
+ if (!states[i]->consistent)
+ for (j = 0; j < states[i]->reductions->nreds; j++)
+ *np++ = &rules[states[i]->reductions->rules[j]];
}
static void
set_goto_map (void)
{
- int state, i;
+ state_number_t state;
short *temp_map;
goto_map = XCALLOC (short, nvars + 1) - ntokens;
ngotos = 0;
for (state = 0; state < nstates; ++state)
{
- shifts *sp = state_table[state]->shifts;
+ shifts_t *sp = states[state]->shifts;
+ int i;
for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
{
- if (ngotos == MAXSHORT)
- fatal (_("too many gotos (max %d)"), MAXSHORT);
+ if (ngotos == SHRT_MAX)
+ fatal (_("too many gotos (max %d)"), SHRT_MAX);
ngotos++;
goto_map[SHIFT_SYMBOL (sp, i)]++;
{
int k = 0;
+ int i;
for (i = ntokens; i < nsyms; i++)
{
temp_map[i] = k;
temp_map[nsyms] = ngotos;
}
- from_state = XCALLOC (short, ngotos);
- to_state = XCALLOC (short, ngotos);
+ from_state = XCALLOC (state_number_t, ngotos);
+ to_state = XCALLOC (state_number_t, ngotos);
for (state = 0; state < nstates; ++state)
{
- shifts *sp = state_table[state]->shifts;
+ shifts_t *sp = states[state]->shifts;
+ int i;
for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
{
int k = temp_map[SHIFT_SYMBOL (sp, i)]++;
`----------------------------------------------------------*/
static int
-map_goto (int state, int symbol)
+map_goto (state_number_t state, symbol_number_t symbol)
{
int high;
int low;
int middle;
- int s;
+ state_number_t s;
low = goto_map[symbol];
high = goto_map[symbol + 1] - 1;
int i;
- F = XCALLOC (unsigned, ngotos * tokensetsize);
+ F = bitsetv_create (ngotos, ntokens, BITSET_FIXED);
for (i = 0; i < ngotos; i++)
{
- int stateno = to_state[i];
- shifts *sp = state_table[stateno]->shifts;
+ state_number_t stateno = to_state[i];
+ shifts_t *sp = states[stateno]->shifts;
int j;
for (j = 0; j < sp->nshifts && SHIFT_IS_SHIFT (sp, j); j++)
- SETBIT (F (i), SHIFT_SYMBOL (sp, j));
+ bitset_set (F[i], SHIFT_SYMBOL (sp, j));
for (; j < sp->nshifts; j++)
{
- int symbol = SHIFT_SYMBOL (sp, j);
+ symbol_number_t 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);
+ memcpy (reads[i], edge, nedges * sizeof (edge[0]));
reads[i][nedges] = -1;
nedges = 0;
}
}
- digraph (reads);
+ relation_digraph (reads, ngotos, &F);
for (i = 0; i < ngotos; i++)
XFREE (reads[i]);
static void
-add_lookback_edge (state_t *state, int ruleno, int gotono)
+add_lookback_edge (state_t *state, rule_number_t ruleno, int gotono)
{
int i;
shorts *sp;
for (i = 0; i < state->nlookaheads; ++i)
- if (LAruleno[state->lookaheadsp + i] == ruleno)
+ if (state->lookaheads_rule[i]->number == ruleno)
break;
- assert (LAruleno[state->lookaheadsp + i] == ruleno);
+ assert (state->lookaheads_rule[i]->number == ruleno);
sp = XCALLOC (shorts, 1);
- sp->next = lookback[state->lookaheadsp + i];
+ sp->next = lookback[(state->lookaheads - LA) + i];
sp->value = gotono;
- 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);
+ lookback[(state->lookaheads - LA) + i] = sp;
}
-/*-------------------------------------------------------------------.
-| 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)
- {
- fputs ("transpose: input\n", stderr);
- matrix_print (stderr, R_arg, 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);
- 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)
- {
- *end_R[R_arg[i][j]] = i;
- ++end_R[R_arg[i][j]];
- }
-
- 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)
- {
- fputs ("transpose: output\n", stderr);
- matrix_print (stderr, new_R, n);
- }
-
- return new_R;
-}
static void
build_relations (void)
{
short *edge = XCALLOC (short, ngotos + 1);
- short *states = XCALLOC (short, ritem_longest_rhs () + 1);
+ state_number_t *states1 = XCALLOC (state_number_t, ritem_longest_rhs () + 1);
int i;
includes = XCALLOC (short *, ngotos);
for (i = 0; i < ngotos; i++)
{
int nedges = 0;
- int symbol1 = state_table[to_state[i]]->accessing_symbol;
- short *rulep;
+ symbol_number_t symbol1 = states[to_state[i]]->accessing_symbol;
+ rule_number_t *rulep;
for (rulep = derives[symbol1]; *rulep > 0; rulep++)
{
int done;
int length = 1;
- short *rp;
- state_t *state = state_table[from_state[i]];
- states[0] = state->number;
+ item_number_t *rp;
+ state_t *state = states[from_state[i]];
+ states1[0] = state->number;
- for (rp = &ritem[rule_table[*rulep].rhs]; *rp >= 0; rp++)
+ for (rp = rules[*rulep].rhs; *rp >= 0; rp++)
{
- shifts *sp = state->shifts;
- int j;
- for (j = 0; j < sp->nshifts; j++)
- {
- state = state_table[sp->shifts[j]];
- if (state->accessing_symbol == *rp)
- break;
- }
-
- states[length++] = state->number;
+ state = shifts_to (state->shifts,
+ item_number_as_symbol_number (*rp));
+ states1[length++] = state->number;
}
if (!state->consistent)
/* JF added rp>=ritem && I hope to god its right! */
if (rp >= ritem && ISVAR (*rp))
{
- edge[nedges++] = map_goto (states[--length], *rp);
+ /* Downcasting from item_number_t to symbol_number_t. */
+ edge[nedges++] = map_goto (states1[--length],
+ item_number_as_symbol_number (*rp));
if (nullable[*rp])
done = 0;
}
}
XFREE (edge);
- XFREE (states);
+ XFREE (states1);
- includes = transpose (includes, ngotos);
+ relation_transpose (&includes, ngotos);
}
{
int i;
- digraph (includes);
+ relation_digraph (includes, ngotos, &F);
for (i = 0; i < ngotos; i++)
XFREE (includes[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];
- }
+ bitset_or (LA[i], LA[i], F[sp->value]);
/* Free LOOKBACK. */
for (i = 0; i < nLA; i++)
LIST_FREE (shorts, lookback[i]);
XFREE (lookback);
- XFREE (F);
+ bitsetv_free (F);
}
-/*--------------------------------------.
-| Initializing the lookaheads members. |
-`--------------------------------------*/
+/*-------------------------------------------------------------.
+| Count the number of lookaheads required for each state |
+| (NLOOKAHEADS member). Compute the total number of LA, NLA. |
+`-------------------------------------------------------------*/
static void
-initialize_lookaheads (void)
+states_lookaheads_count (void)
{
- int i;
+ state_number_t i;
nLA = 0;
+
+ /* Count */
for (i = 0; i < nstates; i++)
{
int k;
int nlookaheads = 0;
- reductions *rp = state_table[i]->reductions;
- shifts *sp = state_table[i]->shifts;
+ reductions_t *rp = states[i]->reductions;
+ shifts_t *sp = states[i]->shifts;
/* We need a lookahead either to distinguish different
reductions (i.e., there are two or more), or to distinguish a
|| (rp->nreds == 1 && sp->nshifts && SHIFT_IS_SHIFT (sp, 0)))
nlookaheads += rp->nreds;
else
- state_table[i]->consistent = 1;
+ states[i]->consistent = 1;
for (k = 0; k < sp->nshifts; k++)
if (SHIFT_IS_ERROR (sp, k))
{
- state_table[i]->consistent = 0;
+ states[i]->consistent = 0;
break;
}
- state_table[i]->nlookaheads = nlookaheads;
- state_table[i]->lookaheadsp = nLA;
+ states[i]->nlookaheads = nlookaheads;
nLA += nlookaheads;
}
}
+
+/*--------------------------------------.
+| Initializing the lookaheads members. |
+`--------------------------------------*/
+
+static void
+states_lookaheads_initialize (void)
+{
+ state_number_t i;
+ bitsetv pLA = LA;
+ rule_t **pLArule = LArule;
+
+ /* Initialize the members LOOKAHEADS and LOOKAHEADS_RULE for each
+ state. */
+ for (i = 0; i < nstates; i++)
+ {
+ states[i]->lookaheads = pLA;
+ states[i]->lookaheads_rule = pLArule;
+ pLA += states[i]->nlookaheads;
+ pLArule += states[i]->nlookaheads;
+ }
+}
+
+
+/*---------------------------------------.
+| Output the lookaheads for each state. |
+`---------------------------------------*/
+
+static void
+lookaheads_print (FILE *out)
+{
+ state_number_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 (states[i]->lookaheads[j], k))
+ fprintf (out, " on %d (%s) -> rule %d\n",
+ k, symbol_tag_get (symbols[k]),
+ states[i]->lookaheads_rule[j]->number - 1);
+ }
+ fprintf (out, "Lookaheads: END\n");
+}
+
void
lalr (void)
{
- tokensetsize = WORDSIZE (ntokens);
-
- initialize_lookaheads ();
+ states_lookaheads_count ();
initialize_LA ();
+ states_lookaheads_initialize ();
set_goto_map ();
initialize_F ();
build_relations ();
compute_FOLLOWS ();
compute_lookaheads ();
+
+ if (trace_flag)
+ lookaheads_print (stderr);
}
projects / bison.git / blobdiff