delete not called

delete not called

[Tudor Hulubei]

Hi there,

I think there is a bug in recent snapshots of egcs.  For the appended
example there is no call to operator delete generated for objects of
type Y, so the output looks like:

new: 0x8049928
new: 0x8049938
delete: 0x8049928

gcc-2.8.1 & gcc-2.7.2.3 (and I believe older snapshots of egcs) do
generate the call.

Is this a known problem?

Thanks,
Tudor

P.S.  The version I use is:
Reading specs from /home/tudor/usr/lib/gcc-lib/i686-pc-linux-gnu/egcs-2.91.22/specs
gcc version egcs-2.91.22 980404 (gcc2 ss-980401 experimental)

#include <new>
#include <iostream.h>
#include <stdlib.h>

void *operator new(size_t size)
{
    if (void *ptr = malloc(size)) {
	cerr << "new: " << ptr << endl;
	return ptr;
    }
}

void operator delete(void *ptr)
{
    if (ptr) {
	cerr << "delete: " << ptr << endl;
	free(ptr);
    }
}

class X { public: ~X() {} };
class Y : public X {};

int
main()
{
    X *x = new X();
    Y *y = new Y();

    delete x;
    delete y;
}

Re: delete not called

[Warner Losh]

In message < 13622.59339.352264.243086@hal2.dyn.ml.org > Tudor Hulubei writes:
: Is this a known problem?

It is doing the right thing.

: class X { public: ~X() {} };
: class Y : public X {};

You need to make ~X virtual.

Warner

Re: delete not called

[Tudor Hulubei]

  On Fri, 17 April 1998, Warner Losh wrote:
  > In message < 13622.59339.352264.243086@hal2.dyn.ml.org > Tudor Hulubei writes:
  > : Is this a known problem?
  > 
  > It is doing the right thing.

I don't think so.  Do you mean that the space for Y is never
deallocated?  What does the fact that ~X is virtual has anything to do 
with deallocation?

  > 
  > : class X { public: ~X() {} };
  > : class Y : public X {};
  > 
  > You need to make ~X virtual.

I already tried that, before reporting the bug.  In fact, in my code
~X() _was_ virtual when I noticed the leak.  Try to make ~X() virtual
and you'll see that you still get 2 calls to new and one call to
delete.  Again, gcc-2.8.1 is working fine as do older versions of egcs
(I tried egcs 1.0 and it used to work with older snapshots).

Regards,
Tudor

Re: delete not called

[Tudor Hulubei]

  On Fri, 17 April 1998, Warner Losh wrote:
  > In message < 13622.59339.352264.243086@hal2.dyn.ml.org > Tudor Hulubei writes:
  > : Is this a known problem?
  > 
  > It is doing the right thing.
  > 
  > : class X { public: ~X() {} };
  > : class Y : public X {};
  > 
  > You need to make ~X virtual.

I have updated my CVS tree and managed to compile the latest version
on Linux (now that the compilation failure has been fixed) and the
problem is gone.  Both calls to delete are now correctly generated.

I am running in some other compiler failures, but this time they are
internal compiler errors.  I couln't reproduce it in a smaller
example, but I'll keep trying :-)

/home/tudor/usr/include/g++/stl_deque.h: In method `void deque<CSPConstraint *,__default_alloc_template<true,0>,0>::clear<CSPConstraint *, alloc, 0>()':
/home/tudor/usr/include/g++/stl_deque.h:769: Internal compiler error.
/home/tudor/usr/include/g++/stl_deque.h:769: Please submit a full bug report to `egcs-bugs@cygnus.com'.
make: *** [CSPac3.o] Error 1

I haven't had this problem with 980406.

Regards,
Tudor