[Bug debug/49951] [4.5/4.6/4.7 Regression] Debug stepping behavior regarding g++ Class destructor has changed for the worse starting at gcc 4.5.0

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49951

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011.08.03 09:34:43
   Target Milestone|---                         |4.5.4
            Summary|Debug stepping behavior     |[4.5/4.6/4.7 Regression]
                   |regarding g++ Class         |Debug stepping behavior
                   |destructor has changed for  |regarding g++ Class
                   |the worse starting at gcc   |destructor has changed for
                   |4.5.0                       |the worse starting at gcc
                   |                            |4.5.0
     Ever Confirmed|0                           |1
      Known to fail|                            |4.5.3, 4.6.1, 4.7.0

--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-08-03 09:34:43 UTC ---
Confirmed.

The destruction is implemented via a try {} finally where the finally
block seems to get the source location of the construction of the
object rather than the source location of it going out of scope:

int main(int, char**) (int argc, char * * argv)
{
  int D.2623;

  [t.C : 19:5] {
    int i;
    struct MyClass m;

    [t.C : 13:11] i = 1;
    [t.C : 14:11] MyClass::MyClass ([t.C : 14] &m);
    [t.C : 19:5] try
      {
        [t.C : 16:3] if (i == 1) goto <D.2620>; else goto <D.2621>;
        <D.2620>:
        [t.C : 18:37] printf ("Hello world %d\n", i);
        goto <D.2622>;
        <D.2621>:
        <D.2622>:
      }
    finally
      {
        [t.C : 14:11] MyClass::~MyClass ([t.C : 14] &m);
      }
  }
  [t.C : 0:0] D.2623 = 0;
  [t.C : 0:0] return D.2623;
}


With 4.4 we still had

int main(int, char**) (int argc, char * * argv)
{
  int D.2628;

  [t.C : 19] {
    int i;
    struct MyClass m;

    [t.C : 13] i = 1;
    [t.C : 14] __comp_ctor  ([t.C : 14] &m);
    [t.C : 19] try
      {
        [t.C : 16] if (i == 1) goto <D.2625>; else goto <D.2626>;
        <D.2625>:
        [t.C : 18] printf (&"Hello world %d\n"[0], i);
        goto <D.2627>;
        <D.2626>:
        <D.2627>:
      }
    finally
      {
        [t.C : 19] __comp_dtor  ([t.C : 19] &m);
      }
  }
  [t.C : 0] D.2628 = 0;
  [t.C : 0] return D.2628;
}

So the finally block stmts inherit the try/finally location.

Might be a gimplification or frontend issue.