Re: One question on the source code of tree-object-size.cc

[Siddhesh Poyarekar]

On 2023-08-02 10:02, Qing Zhao wrote:
   /*when checking the observed access p->array, we only have info on the
     observed access, i.e, the TYPE_SIZE info from the access. We don't have
     info on the whole object.  */
   expect(__builtin_dynamic_object_size(q->array, 1), q->foo * sizeof(int));
   expect(__builtin_dynamic_object_size(q->array, 0), -1);
   expect(__builtin_dynamic_object_size(q->array, 3), q->foo * sizeof(int));
   expect(__builtin_dynamic_object_size(q->array, 2), 0);
   /*when checking the pointer p, we have no observed allocation nor observed 
access.
     therefore, we cannot determine the size info here.  */
   expect(__builtin_dynamic_object_size(q, 1), -1);
   expect(__builtin_dynamic_object_size(q, 0), -1);
   expect(__builtin_dynamic_object_size(q, 3), 0);
   expect(__builtin_dynamic_object_size(q, 2), 0);

I'm wondering if we could sizeof (*q) + q->foo for __bdos(q, 0), but I 
suppose it could mean generating code that potentially dereferences an 
invalid pointer.  Surely we could emit that for __bdos(q->array, 0) 
though, couldn't we?

Thanks,
Sid