X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/9801d40c506b718971aed52c44975c7951bcb3bc..3df374151b36bb8693842c09a1904aeffc358b93:/src/lalr.c?ds=sidebyside

diff --git a/src/lalr.c b/src/lalr.c
index 14a3e231..8fb3c29e 100644
--- a/src/lalr.c
+++ b/src/lalr.c
@@ -27,11 +27,11 @@
 #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 "complain.h"
 #include "lalr.h"
@@ -39,147 +39,63 @@
 #include "derives.h"
 #include "getargs.h"
 
-/* All the decorated states, indexed by the state number.  */
-state_t **states = 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;
 
-rule_t **LArule = NULL;
-bitsetv LA = NULL;
-size_t nLA;
-
-static int ngotos;
-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 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;
-  int height;
-
-  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]];
-
-	bitset_or (F[i], F[i], F[R[i][j]]);
-      }
-
-  if (INDEX[i] == height)
-    for (;;)
-      {
-	j = VERTICES[top--];
-	INDEX[j] = infinity;
-
-	if (i == j)
-	  break;
-
-	bitset_copy (F[j], F[i]);
-      }
-}
-
-
-static void
-digraph (short **relation)
+/* Linked list of goto numbers.  */
+typedef struct goto_list_s
 {
-  int i;
-
-  infinity = ngotos + 2;
-  INDEX = XCALLOC (short, ngotos + 1);
-  VERTICES = XCALLOC (short, ngotos + 1);
-  top = 0;
+  struct goto_list_s *next;
+  goto_number_t value;
+} goto_list_t;
 
-  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);
+/* 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.  */
 
-  XFREE (INDEX);
-  XFREE (VERTICES);
-}
+static bitsetv LA = NULL;
+size_t nLA;
 
 
-static void
-initialize_LA (void)
-{
-  size_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->nreds; j++)
-	*np++ = &rules[states[i]->reductions->rules[j]];
-}
 
 
 static void
 set_goto_map (void)
 {
-  size_t state;
-  int i;
-  short *temp_map;
+  state_number_t state;
+  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)
     {
-      shifts *sp = states[state]->shifts;
-      for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
+      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);
-
+	  assert (ngotos < GOTO_NUMBER_MAX);
 	  ngotos++;
-	  goto_map[SHIFT_SYMBOL (sp, i)]++;
+	  goto_map[TRANSITION_SYMBOL (sp, i)]++;
 	}
     }
 
   {
     int k = 0;
+    int i;
     for (i = ntokens; i < nsyms; i++)
       {
 	temp_map[i] = k;
@@ -193,17 +109,18 @@ set_goto_map (void)
     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 = states[state]->shifts;
-      for (i = sp->nshifts - 1; i >= 0 && SHIFT_IS_GOTO (sp, i); --i)
+      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[SHIFT_SYMBOL (sp, i)]++;
+	  int k = temp_map[TRANSITION_SYMBOL (sp, i)]++;
 	  from_state[k] = state;
-	  to_state[k] = sp->shifts[i];
+	  to_state[k] = sp->states[i]->number;
 	}
     }
 
@@ -217,12 +134,12 @@ set_goto_map (void)
 `----------------------------------------------------------*/
 
 static int
-map_goto (int state, symbol_number_t 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;
@@ -248,8 +165,8 @@ map_goto (int state, symbol_number_t symbol)
 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;
@@ -258,30 +175,30 @@ initialize_F (void)
 
   for (i = 0; i < ngotos; i++)
     {
-      int stateno = to_state[i];
-      shifts *sp = states[stateno]->shifts;
+      state_number_t stateno = to_state[i];
+      transitions_t *sp = states[stateno]->transitions;
 
       int j;
-      for (j = 0; j < sp->nshifts && SHIFT_IS_SHIFT (sp, j); j++)
-	bitset_set (F[i], SHIFT_SYMBOL (sp, j));
+      FOR_EACH_SHIFT (sp, j)
+	bitset_set (F[i], TRANSITION_SYMBOL (sp, j));
 
-      for (; j < sp->nshifts; j++)
+      for (; j < sp->num; j++)
 	{
-	  symbol_number_t symbol = SHIFT_SYMBOL (sp, j);
+	  symbol_number_t symbol = TRANSITION_SYMBOL (sp, j);
 	  if (nullable[symbol])
 	    edge[nedges++] = map_goto (stateno, symbol);
 	}
 
       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;
 	}
     }
 
-  digraph (reads);
+  relation_digraph (reads, ngotos, &F);
 
   for (i = 0; i < ngotos; i++)
     XFREE (reads[i]);
@@ -292,126 +209,33 @@ initialize_F (void)
 
 
 static void
-add_lookback_edge (state_t *state, int 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;
-}
-
-
-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->reductions->lookaheads - LA) + r] = 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 *states1 = XCALLOC (short, ritem_longest_rhs () + 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;
-      short *rulep;
+      rule_t **rulep;
 
-      for (rulep = derives[symbol1]; *rulep > 0; rulep++)
+      for (rulep = derives[symbol1]; *rulep; rulep++)
 	{
 	  int done;
 	  int length = 1;
@@ -419,18 +243,10 @@ build_relations (void)
 	  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++)
 	    {
-	      shifts *sp = state->shifts;
-	      int j;
-	      for (j = 0; j < sp->nshifts; j++)
-		{
-		  state = states[sp->shifts[j]];
-		  if (state->accessing_symbol
-		      == item_number_as_symbol_number (*rp))
-		    break;
-		}
-
+	      state = transitions_to (state->transitions,
+				      item_number_as_symbol_number (*rp));
 	      states1[length++] = state->number;
 	    }
 
@@ -458,7 +274,7 @@ build_relations (void)
       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;
@@ -468,7 +284,7 @@ build_relations (void)
   XFREE (edge);
   XFREE (states1);
 
-  includes = transpose (includes, ngotos);
+  relation_transpose (&includes, ngotos);
 }
 
 
@@ -478,7 +294,7 @@ compute_FOLLOWS (void)
 {
   int i;
 
-  digraph (includes);
+  relation_digraph (includes, ngotos, &F);
 
   for (i = 0; i < ngotos; i++)
     XFREE (includes[i]);
@@ -491,7 +307,7 @@ static void
 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)
@@ -499,74 +315,79 @@ compute_lookaheads (void)
 
   /* 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)
 {
-  size_t i;
-  nLA = 0;
-
-  /* Count   */
-  for (i = 0; i < nstates; i++)
-    {
-      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;
-
-      for (k = 0; k < sp->nshifts; k++)
-	if (SHIFT_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)
 {
-  size_t i;
-  bitsetv pLA = LA;
-  rule_t **pLArule = LArule;
+  state_number_t i;
+  bitsetv pLA;
+
+  /* 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;
 
-  /* Initialize the members LOOKAHEADS and LOOKAHEADS_RULE for each
-     state.  */
+  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;
+	}
     }
 }
 
@@ -578,20 +399,31 @@ states_lookaheads_initialize (void)
 static void
 lookaheads_print (FILE *out)
 {
-  size_t i;
+  state_number_t i;
   int j, k;
   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)
-	for (k = 0; k < ntokens; ++k)
-	  if (bitset_test (states[i]->lookaheads[j], k))
+      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, symbol_tag_get (symbols[k]),
-		     states[i]->lookaheads_rule[j]->number - 1);
+		     k, symbols[k]->tag,
+		     reds->rules[j]->number);
+	  };
     }
   fprintf (out, "Lookaheads: END\n");
 }
@@ -599,15 +431,23 @@ lookaheads_print (FILE *out)
 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);
+}