Re: [PATCH, PR 44535] Fix a problem with folding OBJ_TYPE_REFs

[Richard Guenther <rguenther at suse dot de>]

On Mon, 28 Jun 2010, Martin Jambor wrote:

> Ping.  Thanks,

Ok.

Thanks,
Richard.

> Martin
> 
> 
> On Wed, Jun 16, 2010 at 06:20:34PM +0200, Martin Jambor wrote:
> > Hi,
> > 
> > as the testcase shows, my assumption that BASE_BINFOs were reordered
> > in a way that if any of the had virtual functions the first one did
> > too was false.  I do not really remember why I thought this, I must
> > have misunderstood results of some experiments I did last autumn.
> > 
> > The following patch fixes the folding by skipping BASE_BINFOs that do
> > not have virtual functions when looking for the "first" one.
> > 
> > In addition to the request for an approval of the patch, I also have
> > one question.  I believe it would be quite desirable to have a sanity
> > check in gimple_fold_obj_type_ref_known_binfo asserting that
> > BINFO_FLAG_2 is true.  In in the c++ front end this bit is referred to
> > as BINFO_NEW_VTABLE_MARKED.  Should I move the definition of this
> > macro from gcc/cp/cp-tree.h to gcc/tree.h so that we can use it for
> > the assert too?  Would such a patch be accepted?
> > 
> > As usual, I have bootstrapped and tested the patch on x86_64-linux, OK
> > for trunk?
> > 
> > Thanks,
> > 
> > Martin
> > 
> > 
> > 2010-06-16  Martin Jambor  <mjambor@suse.cz>
> > 
> > 	PR c++/44535
> > 	* gimple-fold.c (get_first_base_binfo_with_virtuals): New function.
> > 	(gimple_get_relevant_ref_binfo): Use get_first_base_binfo_with_virtuals
> > 	instead of BINFO_BASE_BINFO.
> > 
> > 	* testsuite/g++.dg/torture/pr44535.C: New file.
> > 
> > Index: icln/gcc/gimple-fold.c
> > ===================================================================
> > --- icln.orig/gcc/gimple-fold.c
> > +++ icln/gcc/gimple-fold.c
> > @@ -1403,6 +1403,22 @@ gimple_fold_builtin (gimple stmt)
> >    return result;
> >  }
> >  
> > +/* Return the first of the base binfos of BINFO that has virtual functions.  */
> > +
> > +static tree
> > +get_first_base_binfo_with_virtuals (tree binfo)
> > +{
> > +  int i;
> > +  tree base_binfo;
> > +
> > +  for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
> > +    if (BINFO_VIRTUALS (base_binfo))
> > +      return base_binfo;
> > +
> > +  return NULL_TREE;
> > +}
> > +
> > +
> >  /* Search for a base binfo of BINFO that corresponds to TYPE and return it if
> >     it is found or NULL_TREE if it is not.  */
> >  
> > @@ -1458,8 +1474,8 @@ gimple_get_relevant_ref_binfo (tree ref,
> >  	      || BINFO_N_BASE_BINFOS (binfo) == 0)
> >  	    return NULL_TREE;
> >  
> > -	  base_binfo = BINFO_BASE_BINFO (binfo, 0);
> > -	  if (BINFO_TYPE (base_binfo) != TREE_TYPE (field))
> > +	  base_binfo = get_first_base_binfo_with_virtuals (binfo);
> > +	  if (base_binfo && BINFO_TYPE (base_binfo) != TREE_TYPE (field))
> >  	    {
> >  	      tree d_binfo;
> >  
> > Index: icln/gcc/testsuite/g++.dg/torture/pr44535.C
> > ===================================================================
> > --- /dev/null
> > +++ icln/gcc/testsuite/g++.dg/torture/pr44535.C
> > @@ -0,0 +1,34 @@
> > +/* { dg-do run } */
> > +
> > +namespace FOO {
> > +
> > +template <typename T>
> > +class A
> > +{
> > +public:
> > +    void Enum();
> > +    virtual void OnProv() = 0;
> > +    virtual ~A() { }
> > +};
> > +typedef A<char> B;
> > +
> > +template<typename T>
> > +void A<T>::Enum ()
> > +{
> > +    OnProv ();
> > +}
> > +} // namespace FOO
> > +
> > +class C {};
> > +
> > +class D: public C, public FOO::B {
> > +public:
> > +    void OnProv() {}
> > +};
> > +
> > +int main(int argc, char *argv[])
> > +{
> > +    D x;
> > +    x.Enum();
> > +    return 0;
> > +}
> > 
> 
> 

-- 
Richard Guenther <rguenther@suse.de>
Novell / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746 - GF: Markus Rex