04-deterministics-conflicts.patch

[Akim Demaille]

Index: ChangeLog
from  Akim Demaille  <address@hidden>

        Let nondeterministic skeletons be usable with deterministic
        tables.

        With the patch, GAWK compiled by GCC without -O2 passes its test
        suite using a GLR parser driven by LALR tables.  It fails with -O2
        because `struct stat' gives two different answers on my machine:
        88 (definition of an auto var) and later 96 (memset on this var).
        Hence the stack is badly corrumpted.  The headers inclusion is to
        blame: if I move the awk.h inclusion before GLR's system header
        inclusion, the two struct stat have the same size.

        * src/tables.c (pack_table): Always create conflict_table.
        (token_actions): Always create conflict_list.
        * data/glr.c (YYFLAG): Remove, unused.

Index: src/output.c
--- src/output.c Wed, 31 Jul 2002 23:35:03 +0200 akim
+++ src/output.c Sun, 13 Oct 2002 18:55:20 +0200 akim
@@ -503,19 +503,19 @@
   muscle_insert_base_table ("check", check,
                            check[0], 1, high + 1);

-  if (glr_parser)
-    {
-      /* GLR parsing slightly modifies yytable and yycheck
-        (and thus yypact) so that in states with unresolved conflicts,
-        the default reduction is not used in the conflicted entries, so
-        that there is a place to put a conflict pointer.  This means that
-        yyconflp and yyconfl are nonsense for a non-GLR parser, so we
-        avoid accidents by not writing them out in that case. */
-      muscle_insert_unsigned_int_table ("conflict_list_heads", conflict_table,
-                                       conflict_table[0], 1, high+1);
-      muscle_insert_unsigned_int_table ("conflicting_rules", conflict_list,
-                            conflict_list[0], 1, conflict_list_cnt);
-    }
+  /* GLR parsing slightly modifies YYTABLE and YYCHECK (and thus
+     YYPACT) so that in states with unresolved conflicts, the default
+     reduction is not used in the conflicted entries, so that there is
+     a place to put a conflict pointer.
+
+     This means that YYCONFLP and YYCONFL are nonsense for a non-GLR
+     parser, so we could avoid accidents by not writing them out in
+     that case.  Nevertheless, it seems even better to be able to use
+     the GLR skeletons even without the non-deterministic tables.  */
+  muscle_insert_unsigned_int_table ("conflict_list_heads", conflict_table,
+                                   conflict_table[0], 1, high+1);
+  muscle_insert_unsigned_int_table ("conflicting_rules", conflict_list,
+                                   conflict_list[0], 1, conflict_list_cnt);
 }

 
Index: src/tables.c
--- src/tables.c Fri, 02 Aug 2002 09:46:40 +0200 akim
+++ src/tables.c Sun, 13 Oct 2002 18:58:21 +0200 akim
@@ -212,8 +212,7 @@

   table = XREALLOC (table, base_t, table_size);
   check = XREALLOC (check, base_t, table_size);
-  if (glr_parser)
-    conflict_table = XREALLOC (conflict_table, unsigned int, table_size);
+  conflict_table = XREALLOC (conflict_table, unsigned int, table_size);

   for (/* Nothing. */; old_size < table_size; ++old_size)
     {
@@ -470,27 +469,22 @@
   symbol_number_t j;
   rule_number_t r;

-  int nconflict = conflicts_total_count ();
+  int nconflict = glr_parser ? conflicts_total_count () : 0;

   yydefact = XCALLOC (rule_number_t, nstates);

   actrow = XCALLOC (action_t, ntokens);
   conflrow = XCALLOC (unsigned int, ntokens);

+  conflict_list = XCALLOC (unsigned int, 1 + 2 * nconflict);
+  conflict_list_free = 2 * nconflict;
+  conflict_list_cnt = 1;
+
   /* Find the rules which are reduced.  */
   if (!glr_parser)
     for (r = 0; r < nrules; ++r)
       rules[r].useful = FALSE;

-  if (glr_parser)
-    {
-      conflict_list = XCALLOC (unsigned int, 1 + 2 * nconflict);
-      conflict_list_free = 2 * nconflict;
-      conflict_list_cnt = 1;
-    }
-  else
-    conflict_list_free = conflict_list_cnt = 0;
-
   for (i = 0; i < nstates; ++i)
     {
       rule_t *default_rule = action_row (states[i]);
@@ -799,8 +793,7 @@
   base = XCALLOC (base_t, nvectors);
   pos = XCALLOC (base_t, nentries);
   table = XCALLOC (base_t, table_size);
-  if (glr_parser)
-    conflict_table = XCALLOC (unsigned int, table_size);
+  conflict_table = XCALLOC (unsigned int, table_size);
   check = XCALLOC (base_t, table_size);

   lowzero = 0;
Index: data/glr.c
--- data/glr.c Sun, 13 Oct 2002 16:16:48 +0200 akim
+++ data/glr.c Sun, 13 Oct 2002 18:27:39 +0200 akim
@@ -220,7 +220,6 @@ m4_define_default([b4_header_guard],

 /* YYFINAL -- State number of the termination state. */
 #define YYFINAL  ]b4_final_state_number[
-#define YYFLAG  ]b4_flag[
 #define YYLAST   ]b4_last[

 /* YYNTOKENS -- Number of terminals. */
@@ -341,17 +340,17 @@ m4_define_default([b4_header_guard],
   ]b4_table[
 };

-/* YYCONFLP[YYPACT[STATE-NUM]] -- pointer into yyconfl of start of list
-   of conflicting reductions corresponding to action entry for state
-   STATE-NUM in yytable.  0 means no conflicts.  The list in yyconfl
-   is terminated by a rule number of 0. */
+/* YYCONFLP[YYPACT[STATE-NUM]] -- Pointer into YYCONFL of start of
+   list of conflicting reductions corresponding to action entry for
+   state STATE-NUM in yytable.  0 means no conflicts.  The list in
+   yyconfl is terminated by a rule number of 0.  */
 static const ]b4_int_type_for([b4_conflict_list_heads])[ yyconflp[] =
 {
   ]b4_conflict_list_heads[
 };

-/* YYCONFL[I] -- lists of conflicting rule numbers, each terminated
-   by 0, pointed into by YYCONFLP. */
+/* YYCONFL[I] -- lists of conflicting rule numbers, each terminated by
+   0, pointed into by YYCONFLP.  */
 ]dnl Do not use b4_int_type_for here, since there are places where
 dnl pointers onto yyconfl are taken, which type is "short *".
 dnl We probably ought to introduce a type for confl.
@@ -1591,7 +1590,7 @@ m4_define_default([b4_header_guard],
          /* Something's not right; we shouldn't be here.  */
          yyFail (yystack, NULL);
        yyj += *yytokenp;
-       if (yyj < 0 || yyj > YYLAST || yycheck[yyj] != *yytokenp)
+       if (yyj < 0 || YYLAST < yyj || yycheck[yyj] != *yytokenp)
          {
            if (yydefact[yystack->yytops.yystates[0]->yylrState] != 0)
              return;