#include "symtab.h"
#include "gram.h"
#include "reader.h"
-#include "types.h"
#include "LR0.h"
#include "complain.h"
#include "lalr.h"
#include "derives.h"
#include "getargs.h"
-rule_t **LArule = NULL;
-bitsetv LA = NULL;
-size_t nLA;
-
-static int ngotos;
-short *goto_map = NULL;
+goto_number_t *goto_map = NULL;
+static goto_number_t ngotos = 0;
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 bitsetv F = NULL;
+/* Linked list of goto numbers. */
+typedef struct goto_list_s
+{
+ struct goto_list_s *next;
+ goto_number_t value;
+} goto_list_t;
-static short **includes;
-static shorts **lookback;
+/* LA is a LR by NTOKENS matrix of bits. LA[l, i] is 1 if the rule
+ LArule[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. */
+static bitsetv LA = NULL;
+size_t nLA;
-static void
-initialize_LA (void)
-{
- state_number_t i;
- int j;
- rule_t **np;
+/* And for the famous F variable, which name is so descriptive that a
+ comment is hardly needed. <grin>. */
+static bitsetv F = NULL;
- /* Avoid having to special case 0. */
- if (!nLA)
- nLA = 1;
+static goto_number_t **includes;
+static goto_list_t **lookback;
- LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
- LArule = XCALLOC (rule_t *, nLA);
- lookback = XCALLOC (shorts *, nLA);
- np = LArule;
- for (i = 0; i < nstates; i++)
- if (!states[i]->consistent)
- for (j = 0; j < states[i]->reductions->num; j++)
- *np++ = &rules[states[i]->reductions->rules[j]];
-}
static void
set_goto_map (void)
{
state_number_t state;
- short *temp_map;
+ goto_number_t *temp_map;
- goto_map = XCALLOC (short, nvars + 1) - ntokens;
- temp_map = XCALLOC (short, nvars + 1) - ntokens;
+ goto_map = XCALLOC (goto_number_t, nvars + 1) - ntokens;
+ temp_map = XCALLOC (goto_number_t, nvars + 1) - ntokens;
ngotos = 0;
for (state = 0; state < nstates; ++state)
{
- transitions_t *sp = states[state]->shifts;
+ transitions_t *sp = states[state]->transitions;
int i;
for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
{
- if (ngotos == SHRT_MAX)
- fatal (_("too many gotos (max %d)"), SHRT_MAX);
+ if (ngotos == GOTO_NUMBER_MAX)
+ fatal (_("too many gotos (max %d)"), GOTO_NUMBER_MAX);
ngotos++;
goto_map[TRANSITION_SYMBOL (sp, i)]++;
for (state = 0; state < nstates; ++state)
{
- transitions_t *sp = states[state]->shifts;
+ transitions_t *sp = states[state]->transitions;
int i;
for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
{
int k = temp_map[TRANSITION_SYMBOL (sp, i)]++;
from_state[k] = state;
- to_state[k] = sp->states[i];
+ to_state[k] = sp->states[i]->number;
}
}
static void
initialize_F (void)
{
- short **reads = XCALLOC (short *, ngotos);
- short *edge = XCALLOC (short, ngotos + 1);
+ goto_number_t **reads = XCALLOC (goto_number_t *, ngotos);
+ goto_number_t *edge = XCALLOC (goto_number_t, ngotos + 1);
int nedges = 0;
int i;
for (i = 0; i < ngotos; i++)
{
state_number_t stateno = to_state[i];
- transitions_t *sp = states[stateno]->shifts;
+ transitions_t *sp = states[stateno]->transitions;
int j;
- for (j = 0; j < sp->num && TRANSITION_IS_SHIFT (sp, j); j++)
+ FOR_EACH_SHIFT (sp, j)
bitset_set (F[i], TRANSITION_SYMBOL (sp, j));
for (; j < sp->num; j++)
if (nedges)
{
- reads[i] = XCALLOC (short, nedges + 1);
+ reads[i] = XCALLOC (goto_number_t, nedges + 1);
memcpy (reads[i], edge, nedges * sizeof (edge[0]));
reads[i][nedges] = -1;
nedges = 0;
static void
-add_lookback_edge (state_t *state, rule_number_t ruleno, int gotono)
+add_lookback_edge (state_t *state, rule_t *rule, int gotono)
{
- int i;
- shorts *sp;
-
- for (i = 0; i < state->nlookaheads; ++i)
- if (state->lookaheads_rule[i]->number == ruleno)
- break;
-
- assert (state->lookaheads_rule[i]->number == ruleno);
-
- sp = XCALLOC (shorts, 1);
- sp->next = lookback[(state->lookaheads - LA) + i];
+ int r = state_reduction_find (state, rule);
+ goto_list_t *sp = XCALLOC (goto_list_t, 1);
+ sp->next = lookback[(state->reductions->lookaheads - LA) + r];
sp->value = gotono;
- lookback[(state->lookaheads - LA) + i] = sp;
+ lookback[(state->reductions->lookaheads - LA) + r] = sp;
}
static void
build_relations (void)
{
- short *edge = XCALLOC (short, ngotos + 1);
+ goto_number_t *edge = XCALLOC (goto_number_t, ngotos + 1);
state_number_t *states1 = XCALLOC (state_number_t, ritem_longest_rhs () + 1);
int i;
- includes = XCALLOC (short *, ngotos);
+ includes = XCALLOC (goto_number_t *, ngotos);
for (i = 0; i < ngotos; i++)
{
int nedges = 0;
symbol_number_t symbol1 = states[to_state[i]]->accessing_symbol;
- rule_number_t *rulep;
+ rule_t **rulep;
- for (rulep = derives[symbol1]; *rulep > 0; rulep++)
+ for (rulep = derives[symbol1]; *rulep; rulep++)
{
int done;
int length = 1;
state_t *state = states[from_state[i]];
states1[0] = state->number;
- for (rp = rules[*rulep].rhs; *rp >= 0; rp++)
+ for (rp = (*rulep)->rhs; *rp >= 0; rp++)
{
- state = transitions_to (state->shifts,
- item_number_as_symbol_number (*rp));
+ state = transitions_to (state->transitions,
+ item_number_as_symbol_number (*rp));
states1[length++] = state->number;
}
if (nedges)
{
int j;
- includes[i] = XCALLOC (short, nedges + 1);
+ includes[i] = XCALLOC (goto_number_t, nedges + 1);
for (j = 0; j < nedges; j++)
includes[i][j] = edge[j];
includes[i][nedges] = -1;
compute_lookaheads (void)
{
size_t i;
- shorts *sp;
+ goto_list_t *sp;
for (i = 0; i < nLA; i++)
for (sp = lookback[i]; sp; sp = sp->next)
/* Free LOOKBACK. */
for (i = 0; i < nLA; i++)
- LIST_FREE (shorts, lookback[i]);
+ LIST_FREE (goto_list_t, lookback[i]);
XFREE (lookback);
bitsetv_free (F);
}
-/*-------------------------------------------------------------.
-| Count the number of lookaheads required for each state |
-| (NLOOKAHEADS member). Compute the total number of LA, NLA. |
-`-------------------------------------------------------------*/
+/*---------------------------------------------------------------.
+| Count the number of lookaheads required for STATE (NLOOKAHEADS |
+| member). |
+`---------------------------------------------------------------*/
-static void
-states_lookaheads_count (void)
+static int
+state_lookaheads_count (state_t *state)
{
- state_number_t i;
- nLA = 0;
-
- /* Count */
- for (i = 0; i < nstates; i++)
- {
- int k;
- int nlookaheads = 0;
- reductions_t *rp = states[i]->reductions;
- transitions_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
- reduction from a shift. Otherwise, it is straightforward,
- and the state is `consistent'. */
- if (rp->num > 1
- || (rp->num == 1 && sp->num && TRANSITION_IS_SHIFT (sp, 0)))
- nlookaheads += rp->num;
- else
- states[i]->consistent = 1;
-
- for (k = 0; k < sp->num; k++)
- if (TRANSITION_IS_ERROR (sp, k))
- {
- states[i]->consistent = 0;
- break;
- }
+ int k;
+ int nlookaheads = 0;
+ reductions_t *rp = state->reductions;
+ transitions_t *sp = state->transitions;
+
+ /* 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->num > 1
+ || (rp->num == 1 && sp->num &&
+ !TRANSITION_IS_DISABLED (sp, 0) && TRANSITION_IS_SHIFT (sp, 0)))
+ nlookaheads += rp->num;
+ else
+ state->consistent = 1;
+
+ for (k = 0; k < sp->num; k++)
+ if (!TRANSITION_IS_DISABLED (sp, k) && TRANSITION_IS_ERROR (sp, k))
+ {
+ state->consistent = 0;
+ break;
+ }
- states[i]->nlookaheads = nlookaheads;
- nLA += nlookaheads;
- }
+ return nlookaheads;
}
-/*--------------------------------------.
-| Initializing the lookaheads members. |
-`--------------------------------------*/
+/*----------------------------------------------.
+| Compute LA, NLA, and the lookaheads members. |
+`----------------------------------------------*/
static void
-states_lookaheads_initialize (void)
+initialize_LA (void)
{
state_number_t i;
- bitsetv pLA = LA;
- rule_t **pLArule = LArule;
+ bitsetv pLA;
- /* Initialize the members LOOKAHEADS and LOOKAHEADS_RULE for each
- state. */
+ /* Compute the total number of reductions requiring a lookahead. */
+ nLA = 0;
+ for (i = 0; i < nstates; i++)
+ nLA += state_lookaheads_count (states[i]);
+ /* Avoid having to special case 0. */
+ if (!nLA)
+ nLA = 1;
+
+ pLA = LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
+ lookback = XCALLOC (goto_list_t *, nLA);
+
+ /* Initialize the members LOOKAHEADS for each state which reductions
+ require lookaheads. */
for (i = 0; i < nstates; i++)
{
- states[i]->lookaheads = pLA;
- states[i]->lookaheads_rule = pLArule;
- pLA += states[i]->nlookaheads;
- pLArule += states[i]->nlookaheads;
+ int count = state_lookaheads_count (states[i]);
+ if (count)
+ {
+ states[i]->reductions->lookaheads = pLA;
+ pLA += count;
+ }
}
}
fprintf (out, "Lookaheads: BEGIN\n");
for (i = 0; i < nstates; ++i)
{
+ reductions_t *reds = states[i]->reductions;
+ bitset_iterator iter;
+ int nlookaheads = 0;
+
+ if (reds->lookaheads)
+ for (k = 0; k < reds->num; ++k)
+ if (reds->lookaheads[k])
+ ++nlookaheads;
+
fprintf (out, "State %d: %d lookaheads\n",
- i, states[i]->nlookaheads);
+ i, nlookaheads);
- for (j = 0; j < states[i]->nlookaheads; ++j)
- BITSET_EXECUTE (states[i]->lookaheads[j], 0, k,
- {
- fprintf (out, " on %d (%s) -> rule %d\n",
- k, symbols[k]->tag,
- states[i]->lookaheads_rule[j]->number - 1);
- });
+ if (reds->lookaheads)
+ for (j = 0; j < reds->num; ++j)
+ BITSET_FOR_EACH (iter, reds->lookaheads[j], k, 0)
+ {
+ fprintf (out, " on %d (%s) -> rule %d\n",
+ k, symbols[k]->tag,
+ reds->rules[j]->number);
+ };
}
fprintf (out, "Lookaheads: END\n");
}
void
lalr (void)
{
- states_lookaheads_count ();
initialize_LA ();
- states_lookaheads_initialize ();
set_goto_map ();
initialize_F ();
build_relations ();
compute_FOLLOWS ();
compute_lookaheads ();
- if (trace_flag)
+ if (trace_flag & trace_sets)
lookaheads_print (stderr);
}
+
+
+void
+lalr_free (void)
+{
+ state_number_t s;
+ for (s = 0; s < nstates; ++s)
+ states[s]->reductions->lookaheads = NULL;
+ bitsetv_free (LA);
+}
projects / bison.git / blobdiff