Finish implementing %define lr.type.

Its value can be "LALR", "IELR", or "canonical LR".
* lib/timevar.def (TV_IELR_PHASE1): New var.
(TV_IELR_PHASE2): New var.
(TV_IELR_PHASE3): New var.
(TV_IELR_PHASE4): New var.
* src/local.mk (src_bison_SOURCES): Add AnnotationList.c,
AnnotationList.h, InadequacyList.c, InadequacyList.h, Sbitset.c,
Sbitset.h, ielr.c, and ielr.h.
* src/getargs.h, src/getargs.c (enum trace, trace_args,
trace_types): Add trace_ielr.
* src/lalr.h, src/lalr.c (ngotos): Export it.
(F): Rename to...
(goto_follows): ... this, update all uses, and export it.
(set_goto_map): Export it.
(map_goto): Export it.
(compute_lookahead_tokens): Don't free goto_follows yet.  Now
handled in ielr.
(initialize_LA): Export it.  Move lookback allocation to...
(lalr): ... here because, for canonical LR, initialize_LA must
be invoked but lookback and much of the rest of LALR isn't
needed.
* main.c (main): Instead of lalr, invoke ielr, which invokes
lalr.
* src/reader.c (reader): Default lr.type to "LALR".
Default lr.default_rules to "accepting" if lr.type is "canonical
LR".  Leave the default as "all" otherwise.
Check for a valid lr.type value.
* src/state.h, src/state.c (struct state_list): Add state_list
member.
(state_new): Initialize state_list member to NULL.
(state_new_isocore): New function, exported.
* tests/existing.at (AT_TEST_EXISTING_GRAMMAR): New macro that
exercises all values of lr.type.
(GNU AWK Grammar): Rename test group to...
(GNU AWK 3.1.0 Grammar): ... this, and extend to use
AT_TEST_EXISTING_GRAMMAR.
(GNU Cim Grammar): Extend to use AT_TEST_EXISTING_GRAMMAR.
(GNU pic Grammar): Rename test group to...
(GNU pic (Groff 1.18.1) Grammar): ... this, and extend to use
AT_TEST_EXISTING_GRAMMAR.
* tests/reduce.at (AT_TEST_LR_TYPE): New macro that exercises
all values of lr.type.
(Single State Split): New test groups using AT_TEST_LR_TYPE.
(Lane Split): Likewise.
(Complex Lane Split): Likewise.
(Split During Added Lookahead Propagation): Likewise.

9 files changed, 111 insertions, 38 deletions

diff --git a/src/getargs.c b/src/getargs.c
index 368470fb..fdf9dd0b 100644
--- a/src/getargs.c
+++ b/src/getargs.c
@@ -186,6 +186,7 @@ static const char * const trace_args[] =
   "m4         - m4 traces",
   "skeleton   - skeleton postprocessing",
   "time       - time consumption",
+  "ielr       - IELR conversion",
   "all        - all of the above",
   0
 };
@@ -205,6 +206,7 @@ static const int trace_types[] =
   trace_m4,
   trace_skeleton,
   trace_time,
+  trace_ielr,
   trace_all
 };
 
diff --git a/src/getargs.h b/src/getargs.h
index 13efae2c..32135b5e 100644
--- a/src/getargs.h
+++ b/src/getargs.h
@@ -103,6 +103,7 @@ enum trace
     trace_skeleton  = 1 << 9,  /**< Skeleton postprocessing. */
     trace_m4        = 1 << 10, /**< M4 traces. */
     trace_muscles   = 1 << 11, /**< M4 definitions of the muscles. */
+    trace_ielr      = 1 << 12, /**< IELR conversion. */
     trace_all       = ~0       /**< All of the above.  */
   };
 /** What debug items bison displays during its run.  */
diff --git a/src/lalr.c b/src/lalr.c
index 27866ecf..4f26a45f 100644
--- a/src/lalr.c
+++ b/src/lalr.c
@@ -43,9 +43,10 @@
 #include "symtab.h"
 
 goto_number *goto_map;
-static goto_number ngotos;
+goto_number ngotos;
 state_number *from_state;
 state_number *to_state;
+bitsetv goto_follows = NULL;
 
 /* Linked list of goto numbers.  */
 typedef struct goto_list
@@ -64,17 +65,13 @@ static bitsetv LA = NULL;
 size_t nLA;
 
 
-/* And for the famous F variable, which name is so descriptive that a
-   comment is hardly needed.  <grin>.  */
-static bitsetv F = NULL;
-
 static goto_number **includes;
 static goto_list **lookback;
 
 
 
 
-static void
+void
 set_goto_map (void)
 {
   state_number s;
@@ -134,12 +131,7 @@ set_goto_map (void)
 }
 
 
-
-/*----------------------------------------------------------.
-| Map a state/symbol pair into its numeric representation.  |
-`----------------------------------------------------------*/
-
-static goto_number
+goto_number
 map_goto (state_number s0, symbol_number sym)
 {
   goto_number high;
@@ -174,7 +166,7 @@ initialize_F (void)
 
   goto_number i;
 
-  F = bitsetv_create (ngotos, ntokens, BITSET_FIXED);
+  goto_follows = bitsetv_create (ngotos, ntokens, BITSET_FIXED);
 
   for (i = 0; i < ngotos; i++)
     {
@@ -183,7 +175,7 @@ initialize_F (void)
 
       int j;
       FOR_EACH_SHIFT (sp, j)
-	bitset_set (F[i], TRANSITION_SYMBOL (sp, j));
+	bitset_set (goto_follows[i], TRANSITION_SYMBOL (sp, j));
 
       for (; j < sp->num; j++)
 	{
@@ -203,7 +195,7 @@ initialize_F (void)
 	}
     }
 
-  relation_digraph (reads, ngotos, &F);
+  relation_digraph (reads, ngotos, &goto_follows);
 
   for (i = 0; i < ngotos; i++)
     free (reads[i]);
@@ -264,7 +256,7 @@ build_relations (void)
 	    {
 	      done = true;
 	      /* Each rhs ends in a rule number, and there is a
-		 sentinel before the first rhs, so it is safe to
+		 sentinel (ritem[-1]=0) before the first rhs, so it is safe to
 		 decrement RP here.  */
 	      rp--;
 	      if (ISVAR (*rp))
@@ -303,7 +295,7 @@ compute_FOLLOWS (void)
 {
   goto_number i;
 
-  relation_digraph (includes, ngotos, &F);
+  relation_digraph (includes, ngotos, &goto_follows);
 
   for (i = 0; i < ngotos; i++)
     free (includes[i]);
@@ -320,14 +312,13 @@ compute_lookahead_tokens (void)
 
   for (i = 0; i < nLA; i++)
     for (sp = lookback[i]; sp; sp = sp->next)
-      bitset_or (LA[i], LA[i], F[sp->value]);
+      bitset_or (LA[i], LA[i], goto_follows[sp->value]);
 
   /* Free LOOKBACK. */
   for (i = 0; i < nLA; i++)
     LIST_FREE (goto_list, lookback[i]);
 
   free (lookback);
-  bitsetv_free (F);
 }
 
 
@@ -373,7 +364,7 @@ state_lookahead_tokens_count (state *s, bool default_rule_only_for_accept)
 | Compute LA, NLA, and the lookahead_tokens members.  |
 `----------------------------------------------------*/
 
-static void
+void
 initialize_LA (void)
 {
   state_number i;
@@ -395,7 +386,6 @@ initialize_LA (void)
     nLA = 1;
 
   pLA = LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
-  lookback = xcalloc (nLA, sizeof *lookback);
 
   /* Initialize the members LOOKAHEAD_TOKENS for each state whose reductions
      require lookahead tokens.  */
@@ -454,6 +444,7 @@ lalr (void)
   initialize_LA ();
   set_goto_map ();
   initialize_F ();
+  lookback = xcalloc (nLA, sizeof *lookback);
   build_relations ();
   compute_FOLLOWS ();
   compute_lookahead_tokens ();
diff --git a/src/lalr.h b/src/lalr.h
index c65c9b48..103a4c86 100644
--- a/src/lalr.h
+++ b/src/lalr.h
@@ -1,7 +1,7 @@
 /* Compute lookahead criteria for bison,
 
-   Copyright (C) 1984, 1986, 1989, 2000, 2002, 2004, 2006, 2007 Free Software
-   Foundation, Inc.
+   Copyright (C) 1984, 1986, 1989, 2000, 2002, 2004, 2006, 2007, 2009
+   Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -37,14 +37,30 @@
    which rules need lookahead in each state, and which lookahead
    tokens they accept.
 
-   Builds:
-   - #goto_map
-   - #from_state
-   - #to_state
+   Also builds:
+     - #goto_map
+     - #from_state
+     - #to_state
+     - #goto_follows
 */
 void lalr (void);
 
 /**
+ * Set #nLA and allocate all reduction lookahead sets.  Normally invoked by
+ * #lalr.
+ */
+void initialize_LA (void);
+
+/**
+ * Build only:
+ *   - #goto_map
+ *   - #from_state
+ *   - #to_state
+ * Normally invoked by #lalr.
+ */
+void set_goto_map (void);
+
+/**
  * Update state numbers recorded in #goto_map, #from_state, and #to_state such
  * that:
  *   - \c nstates_old is the old number of states.
@@ -62,7 +78,6 @@ void lalr_update_state_numbers (state_number old_to_new[],
    Can be performed once the action tables are computed.  */
 void lalr_free (void);
 
-
 typedef size_t goto_number;
 # define GOTO_NUMBER_MAXIMUM ((goto_number) -1)
 
@@ -73,11 +88,20 @@ typedef size_t goto_number;
    TO_STATE of the first of them.  */
 extern goto_number *goto_map;
 
-/** State number which a transition leads from. */
+/** The size of #from_state and #to_state.  */
+extern goto_number ngotos;
+
+/** State number which a transition leads from.  */
 extern state_number *from_state;
 
 /** State number it leads to.  */
 extern state_number *to_state;
 
+/** Map a state/symbol pair into its numeric representation.  */
+goto_number map_goto (state_number s0, symbol_number sym);
+
+/* goto_follows[i] is the set of tokens following goto i.  */
+extern bitsetv goto_follows;
+
 
 #endif /* !LALR_H_ */
diff --git a/src/local.mk b/src/local.mk
index ffcf4b01..bdf9d2e3 100644
--- a/src/local.mk
+++ b/src/local.mk
@@ -34,8 +34,14 @@ EXTRA_SCRIPTS = src/yacc
 
 src_bison_CFLAGS = $(AM_CFLAGS) $(WERROR_CFLAGS)
 src_bison_SOURCES =				\
+  src/AnnotationList.c				\
+  src/AnnotationList.h				\
+  src/InadequacyList.c				\
+  src/InadequacyList.h				\
   src/LR0.c					\
   src/LR0.h					\
+  src/Sbitset.c					\
+  src/Sbitset.h					\
   src/assoc.c					\
   src/assoc.h					\
   src/closure.c					\
@@ -57,6 +63,8 @@ src_bison_SOURCES =				\
   src/graphviz.h				\
   src/lalr.c					\
   src/lalr.h					\
+  src/ielr.c					\
+  src/ielr.h					\
   src/location.c				\
   src/location.h				\
   src/main.c					\
diff --git a/src/main.c b/src/main.c
index d7a7f65f..ed0893fd 100644
--- a/src/main.c
+++ b/src/main.c
@@ -35,6 +35,7 @@
 #include "getargs.h"
 #include "gram.h"
 #include "lalr.h"
+#include "ielr.h"
 #include "muscle-tab.h"
 #include "nullable.h"
 #include "output.h"
@@ -102,10 +103,10 @@ main (int argc, char *argv[])
   generate_states ();
   timevar_pop (TV_LR0);
 
-  /* make it deterministic.  In file lalr.  */
-  timevar_push (TV_LALR);
-  lalr ();
-  timevar_pop (TV_LALR);
+  /* Make it deterministic by computing lookahead sets.  Except when LALR(1) is
+     requested, split states to eliminate LR(1)-relative inadequacies.  In file
+     lalr and ielr.  */
+  ielr ();
 
   /* Find and record any conflicts: places where one token of
      lookahead is not enough to disambiguate the parsing.  In file
diff --git a/src/reader.c b/src/reader.c
index 8c88dc04..f607f9ee 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -555,11 +555,22 @@ reader (void)
   gram_scanner_initialize ();
   gram_parse ();
 
-  muscle_percent_define_default ("lr.default_rules", "all");
+  /* IELR would be a better default, but LALR is historically the default.  */
+  {
+    char *lr_type;
+    muscle_percent_define_default ("lr.type", "LALR");
+    lr_type = muscle_percent_define_get ("lr.type");
+    if (0 != strcmp (lr_type, "canonical LR"))
+      muscle_percent_define_default ("lr.default_rules", "all");
+    else
+      muscle_percent_define_default ("lr.default_rules", "accepting");
+    free (lr_type);
+  }
 
   /* Check front-end %define variable values.  */
   {
     static char const * const values[] = {
+      "lr.type", "LALR", "IELR", "canonical LR", NULL,
       "lr.default_rules", "all", "consistent", "accepting", NULL,
       NULL
     };
diff --git a/src/state.c b/src/state.c
index d3460c15..a0f5cdb8 100644
--- a/src/state.c
+++ b/src/state.c
@@ -1,7 +1,7 @@
 /* Type definitions for nondeterministic finite state machine for Bison.
 
-   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software
-   Foundation, Inc.
+   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009 Free
+   Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -142,6 +142,7 @@ state_new (symbol_number accessing_symbol,
   res->transitions = NULL;
   res->reductions = NULL;
   res->errs = NULL;
+  res->state_list = NULL;
   res->consistent = 0;
   res->solved_conflicts = NULL;
   res->solved_conflicts_xml = NULL;
@@ -154,6 +155,32 @@ state_new (symbol_number accessing_symbol,
   return res;
 }
 
+state *
+state_new_isocore (state const *s)
+{
+  state *res;
+  size_t items_size = s->nitems * sizeof *s->items;
+
+  aver (nstates < STATE_NUMBER_MAXIMUM);
+
+  res = xmalloc (offsetof (state, items) + items_size);
+  res->number = nstates++;
+  res->accessing_symbol = s->accessing_symbol;
+  res->transitions =
+    transitions_new (s->transitions->num, s->transitions->states);
+  res->reductions = reductions_new (s->reductions->num, s->reductions->rules);
+  res->errs = NULL;
+  res->state_list = NULL;
+  res->consistent = s->consistent;
+  res->solved_conflicts = NULL;
+  res->solved_conflicts_xml = NULL;
+
+  res->nitems = s->nitems;
+  memcpy (res->items, s->items, items_size);
+
+  return res;
+}
+
 
 /*---------.
 | Free S.  |
diff --git a/src/state.h b/src/state.h
index 4afc1f00..931b48f1 100644
--- a/src/state.h
+++ b/src/state.h
@@ -1,7 +1,7 @@
 /* Type definitions for nondeterministic finite state machine for Bison.
 
-   Copyright (C) 1984, 1989, 2000, 2001, 2002, 2003, 2004, 2007 Free
-   Software Foundation, Inc.
+   Copyright (C) 1984, 1989, 2000, 2001, 2002, 2003, 2004, 2007, 2009
+   Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -193,6 +193,8 @@ typedef struct
 | states.  |
 `---------*/
 
+struct state_list;
+
 struct state
 {
   state_number number;
@@ -201,6 +203,11 @@ struct state
   reductions *reductions;
   errs *errs;
 
+  /* When an includer (such as ielr.c) needs to store states in a list, the
+     includer can define struct state_list as the list node structure and can
+     store in this member a reference to the node containing each state.  */
+  struct state_list *state_list;
+
   /* If non-zero, then no lookahead sets on reduce actions are needed to
      decide what to do in state S.  */
   char consistent;
@@ -222,6 +229,7 @@ extern state *final_state;
 /* Create a new state with ACCESSING_SYMBOL for those items.  */
 state *state_new (symbol_number accessing_symbol,
 		  size_t core_size, item_number *core);
+state *state_new_isocore (state const *s);
 
 /* Set the transitions of STATE.  */
 void state_transitions_set (state *s, int num, state **trans);