Re: How to access the virtual table?

[Jan Hubicka <hubicka at ucw dot cz>]

> 
> I am trying to access the virtual table.
> My pass is hooked after pass_ipa_pta.
> 
> Consider Class A which contains virtual function.
> An object created as :
>     A a;
> is translated in GIMPLE as
>     struct A a;
> 
> From variable "a" we can get its type which is "struct A".
> I tried to see how the dump_vtable function access the table.
> 
> To access the virtual table for class A, Below is the code which I tried.
> 
>     tree t = TREE_TYPE (a);
>     tree binfo = TYPE_BINFO (t);
>     tree vtab = BINFO_VTABLE (binfo);
> 
>     FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (DECL_INITIAL
> (vtab)), ix, value)
> 
> Using the above iterator, entries of the virtual table should be accessible.
> However, I am not able to do so.

You can check dump_tree (vtab) to see if you are seeing an VAR_DECL.  BINFO_VTABLE
is usually POINTER_PLUS_EXPR, so you want to access DECL_INITIAL
of TREE_OPERAND (vtab) in that case.

If you want to access an virtual method with given token (position in vtable),
you can just use gimple_get_virt_method_for_binfo (or borrow code from there
for things you need).

Honza
> 
> Kindly inform me the way to access the virtual table.
> Also how to fetch the functions from that virtual table?
> 
> Regards,
> Swati