Re: temporary workaround for current test failures in lalr1.cc

[Akim Demaille]

>>> "Akim" == Akim Demaille <address@hidden> writes:

 > I'm puzzled.  It depends on the version of G++, but valgrind sees
 > nothing suspicious.  I'll dig.

It also depended on with or without -O2, as do many similar bugs.  It
turned out that we were reading beyond yycheck's size.  And then I
remembered there were patches applied to glr and yacc for this
problem, I only had to port them.

Index: ChangeLog
from  Akim Demaille  <address@hidden>

        * data/lalr1.cc (yyreport_syntax_error_): Catch up with glr.c and
        yacc.c: be sure to stay within yycheck_.
        * tests/actions.at: Re-enable C++ tests.

Index: data/lalr1.cc
===================================================================
RCS file: /cvsroot/bison/bison/data/lalr1.cc,v
retrieving revision 1.71
diff -u -u -r1.71 lalr1.cc
--- data/lalr1.cc 16 Dec 2004 09:06:08 -0000 1.71
+++ data/lalr1.cc 16 Dec 2004 14:28:33 -0000
@@ -810,24 +810,30 @@
       yyn_ = yypact_[yystate_];
       if (yypact_ninf_ < yyn_ && yyn_ < yylast_)
        {
+         /* Start YYX at -YYN if negative to avoid negative indexes in
+            YYCHECK.  */
+         int yyxbegin = yyn_ < 0 ? -yyn_ : 0;
+
+         /* Stay within bounds of both yycheck and yytname.  */
+         int yychecklim = yylast_ - yyn_;
+         int yyxend = yychecklim < yyntokens_ ? yychecklim : yyntokens_;
+          int count = 0;
+          for (int x = yyxbegin; x < yyxend; ++x)
+            if (yycheck_[x + yyn_] == x && x != yyterror_)
+              ++count;
+
          message = "syntax error, unexpected ";
          message += yyname_[yyilooka_];
-         {
-           int count = 0;
-           for (int x = (yyn_ < 0 ? -yyn_ : 0); x < yyntokens_ + yynnts_; ++x)
-             if (yycheck_[x + yyn_] == x && x != yyterror_)
-               ++count;
-           if (count < 5)
-             {
-               count = 0;
-               for (int x = (yyn_ < 0 ? -yyn_ : 0); x < yyntokens_ + yynnts_; 
++x)
-                 if (yycheck_[x + yyn_] == x && x != yyterror_)
-                   {
-                     message += (!count++) ? ", expecting " : " or ";
-                     message += yyname_[x];
-                   }
-             }
-         }
+          if (count < 5)
+            {
+              count = 0;
+              for (int x = yyxbegin; x < yyxend; ++x)
+                if (yycheck_[x + yyn_] == x && x != yyterror_)
+                  {
+                    message += (!count++) ? ", expecting " : " or ";
+                    message += yyname_[x];
+                 }
+            }
        }
       else
 #endif
Index: tests/actions.at
===================================================================
RCS file: /cvsroot/bison/bison/tests/actions.at,v
retrieving revision 1.44
diff -u -u -r1.44 actions.at
--- tests/actions.at 15 Dec 2004 16:18:11 -0000 1.44
+++ tests/actions.at 16 Dec 2004 14:28:33 -0000
@@ -468,10 +468,8 @@
 # These tests currently fail on a Debian GNU/Linux 3.0r2 x86 host,
 # but the 2nd test succeeds on a Solaris 9 sparc hosts (Forte 7 cc).
 # Skip them until we figure out what the problem is.
-AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "lalr1.cc"], ,
-  [AT_CHECK([exit 77])])
-AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "lalr1.cc"], [with union],
-  [AT_CHECK([exit 77])])
+AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "lalr1.cc"])
+AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "lalr1.cc"], [with union])
 
 AT_CHECK_PRINTER_AND_DESTRUCTOR([%glr-parser])
 AT_CHECK_PRINTER_AND_DESTRUCTOR([%glr-parser], [with union])