output: restore yyrhs and yyprhs

[Akim Demaille]

commit e1094c4c09acaa9d942c8e8e271788a9b6ea11df
Author: Akim Demaille <address@hidden>
Date:   Sat Dec 1 07:52:56 2018 +0100

    output: restore yyrhs and yyprhs
    
    This was demanded several times.  See for instance:
    
    - David M. Warme
      https://lists.gnu.org/archive/html/help-bison/2011-04/msg00003.html
    
    - box12009
      http://lists.gnu.org/archive/html/bug-bison/2016-10/msg00001.html
    
    Basically, this reverts:
    
    - commit 3d3bc1fe30f356cf674a979409e86ea0f88de4a0
      Get rid of (yy)rhs and (yy)prhs
    
    - commit d333175f63f402dbadb647175e40ad88bf1defb5
      Avoid compiler warning.
    
    Note that since these tables are not needed in the generated parsers,
    no skeleton requests them.  This change only brings back their
    definition to M4, making it possible to user-defined skeletons to use
    these tables.
    
    * src/output.c (muscle_insert_item_number_table): Define.
    (prepare_rules): Generate the rhs and prhs tables.

diff --git a/src/output.c b/src/output.c
index 96295d17..a6517968 100644
--- a/src/output.c
+++ b/src/output.c
@@ -99,6 +99,7 @@ GENERATE_MUSCLE_INSERT_TABLE (muscle_insert_int_table, int)
 GENERATE_MUSCLE_INSERT_TABLE (muscle_insert_base_table, base_number)
 GENERATE_MUSCLE_INSERT_TABLE (muscle_insert_rule_number_table, rule_number)
 GENERATE_MUSCLE_INSERT_TABLE (muscle_insert_symbol_number_table, symbol_number)
+GENERATE_MUSCLE_INSERT_TABLE (muscle_insert_item_number_table, item_number)
 GENERATE_MUSCLE_INSERT_TABLE (muscle_insert_state_number_table, state_number)
 
 /*----------------------------------------------------------------.
@@ -200,14 +201,16 @@ prepare_symbols (void)
 }
 
 
-/*----------------------------------------------------------------.
-| Prepare the muscles related to the rules: r1, r2, rline, dprec, |
-| merger, immediate.                                              |
-`----------------------------------------------------------------*/
+/*-------------------------------------------------------------.
+| Prepare the muscles related to the rules: rhs, prhs, r1, r2, |
+| rline, dprec, merger, immediate.                             |
+`-------------------------------------------------------------*/
 
 static void
 prepare_rules (void)
 {
+  unsigned *prhs = xnmalloc (nrules, sizeof *prhs);
+  item_number *rhs = xnmalloc (nritems, sizeof *rhs);
   unsigned *rline = xnmalloc (nrules, sizeof *rline);
   symbol_number *r1 = xnmalloc (nrules, sizeof *r1);
   unsigned *r2 = xnmalloc (nrules, sizeof *r2);
@@ -215,14 +218,24 @@ prepare_rules (void)
   int *merger = xnmalloc (nrules, sizeof *merger);
   int *immediate = xnmalloc (nrules, sizeof *immediate);
 
+  /* Index in RHS.  */
+  unsigned i = 0;
   for (rule_number r = 0; r < nrules; ++r)
     {
+      /* Index of rule R in RHS. */
+      prhs[r] = i;
+      /* RHS of the rule R. */
+      for (item_number *rhsp = rules[r].rhs; 0 <= *rhsp; ++rhsp)
+       rhs[i++] = *rhsp;
+      /* Separator in RHS. */
+      rhs[i++] = -1;
+
+      /* Line where rule was defined. */
+      rline[r] = rules[r].location.start.line;
       /* LHS of the rule R. */
       r1[r] = rules[r].lhs->number;
       /* Length of rule R's RHS. */
-      r2[r] = rule_rhs_length (&rules[r]);
-      /* Line where rule was defined. */
-      rline[r] = rules[r].location.start.line;
+      r2[r] = rule_rhs_length(&rules[r]);
       /* Dynamic precedence (GLR).  */
       dprec[r] = rules[r].dprec;
       /* Merger-function index (GLR).  */
@@ -230,7 +243,10 @@ prepare_rules (void)
       /* Immediate reduction flags (GLR).  */
       immediate[r] = rules[r].is_predicate;
     }
+  aver (i == nritems);
 
+  muscle_insert_item_number_table ("rhs", rhs, ritem[0], 1, nritems);
+  muscle_insert_unsigned_int_table ("prhs", prhs, 0, 0, nrules);
   muscle_insert_unsigned_int_table ("rline", rline, 0, 0, nrules);
   muscle_insert_symbol_number_table ("r1", r1, 0, 0, nrules);
   muscle_insert_unsigned_int_table ("r2", r2, 0, 0, nrules);
@@ -241,6 +257,8 @@ prepare_rules (void)
   MUSCLE_INSERT_INT ("rules_number", nrules);
   MUSCLE_INSERT_INT ("max_left_semantic_context", max_left_semantic_context);
 
+  free (prhs);
+  free (rhs);
   free (rline);
   free (r1);
   free (r2);