java/1345: A boolean expression containing two qualified expressions makes jc1 die.

[apbianco@cygnus.com]

>Number:         1345
>Category:       java
>Synopsis:       A boolean expression containing two qualified expressions makes jc1 die.
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    apbianco
>State:          closed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Dec 20 12:19:15 PST 2000
>Closed-Date:    Thu Aug 26 09:56:38 PDT 1999
>Last-Modified:  Thu Aug 26 09:56:38 PDT 1999
>Originator:     Mark K. Gardner (mkgardne@cs.uiuc.edu)
>Release:        Current
>Organization:
>Environment:
Originally unknown. Reproduced on Debian2.0/x86
>Description:
jc1 dies processing the following expression:

  stacks[to].non_empty() 
  && ((disk)stacks[to].top()).id < d.id

which happens to be a `if' statement boolean expression.
>How-To-Repeat:
Run `jc1' on the following source code:

/* Copyright 1993-1999, by the Cecil Project
 * Department of Computer Science and Engineering, University of Washington
 * See the $VORTEX_HOME/notes/LICENSE file for license information.
 */

package towers;

class disk {
        int id;

        disk(int i) { id = i;}
}

class simple_list {
        Object value;
        simple_list next;

        simple_list(Object v, simple_list n) {
                value = v;
                next = n;
        }

        simple_list() {
                value = null;
                next = null;
        }
}

class list extends simple_list {
        simple_list head;

        list() { head = null; }

        void add_first(Object v) { head = new simple_list(v, head); }
        Object remove_first() {
                Object v = head.value;
                head = head.next;
                return v;
        }
        Object first() { return head.value; }
        boolean is_empty() { return head == null; }
        boolean non_empty() { return !is_empty(); }
}

class stack extends list {
        void push(Object v) { add_first(v); }
        Object pop() { return remove_first(); }
        Object top() { return first(); }
}

class towers {
        stack stacks[] = new stack[3];
        int moves_done;

        towers(int size) {
                stack s = new stack();
                for (int i = 0; i < size; i++) {
            s.push(new disk(size - i));
                }
                stacks[0] = s;
                stacks[1] = new stack();
                stacks[2] = new stack();
                moves_done = 0;
        }

        void move_stack(int from, int to, int count) {
                if (count == 0) return;
                int other = 3 - from - to;
                move_stack(from, other, count - 1);
                move_disk(from, to);
                move_stack(other, to, count - 1);
        }

        void move_disk(int from, int to) {
                disk d = (disk)stacks[from].pop();
/* BUGGY */
                if (stacks[to].non_empty() &&
                                ((disk)stacks[to].top()).id < d.id) {
/* OK
                if (false) {
*/
            System.out.println("pushing a disk onto a smaller disk");
            System.exit(-1);
                }
                stacks[to].push(d);
                moves_done++;
        }

        public static void main(String argv[]) {
                int i;
                towers t = null;
                int size = 15;
                long time, time2;
                int iters = 10;

                System.out.print("** Starting towers with " + size + " disks...");
                System.out.flush();
                time = System.currentTimeMillis();
                for (i = 0; i < iters; i++) {
            t = new towers(size);
            t.move_stack(0, 1, size);
                }
                time2 = System.currentTimeMillis();
                System.out.println("done.  " + t.moves_done + " moves; time: "
+
                                ((time2 - time)/iters) + " ms.");
        }
}


>Fix:
Hmm, the patch I provided you with yesterday isn't quite
right. Can you please try this one instead?

Index: parse.y
===================================================================
RCS file: /cvs/cvsfiles/devo/gcc/java/parse.y,v
retrieving revision 1.110
diff -u -p -r1.110 parse.y
--- parse.y     1999/08/22 18:36:05     1.110
+++ parse.y     1999/08/24 07:30:01
@@ -7843,8 +7852,15 @@ qualify_ambiguous_name (id)
        again = 1;
       }
     else 
-      name = EXPR_WFL_NODE (qual_wfl);
-    
+      {
+       name = EXPR_WFL_NODE (qual_wfl);
+       if (!name)
+         {
+           qual = EXPR_WFL_QUALIFICATION (qual_wfl);
+           again = 1;
+         }
+      }
+
     /* If we have a THIS (from a primary), we set the context accordingly */
     if (name == this_identifier_node)
       {
>Release-Note:

>Audit-Trail:

Formerly PR gcj/32

State-Changed-From-To: open->feedback
State-Changed-By: apbianco
State-Changed-When: Mon Aug 23 19:48:37 1999
State-Changed-Why:
    Can you try the following patch?
    
    Index: parse.y
    ===================================================================
    RCS file: /cvs/egcs/egcs/gcc/java/parse.y,v
    retrieving revision 1.104
    diff -u -p -r1.104 parse.y
    --- parse.y     1999/08/22 18:38:07     1.104
    +++ parse.y     1999/08/24 02:43:35
    @@ -7854,9 +7863,14 @@ qualify_ambiguous_name (id)
            qual = TREE_CHAIN (qual);
            qual_wfl = QUAL_WFL (qual);
            again = 1;
    +      }
    +
    +    name = EXPR_WFL_NODE (qual_wfl);
    +    if (!name)
    +      {
    +       qual = EXPR_WFL_QUALIFICATION (qual_wfl);
    +       again = 1;
           }
    -    else 
    -      name = EXPR_WFL_NODE (qual_wfl);
         
         /* If we have a THIS (from a primary), we set the context accordingly */
         if (name == this_identifier_node)
    
State-Changed-From-To: feedback->closed
State-Changed-By: apbianco
State-Changed-When: Thu Aug 26 09:56:38 1999
State-Changed-Why:
    A patch has been checked in. See http://egcs.cygnus.com/ml/gcc-patches/1999-08/msg00782.html
>Unformatted: