https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121000
Bug ID: 121000
Summary: __builtin_dynamic_object_size should work for FAM with
VLA element when annotated with counted_by
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: qinzhao at gcc dot gnu.org
Target Milestone: ---
for the following testing case:
void
foo (int n, int m)
{
typedef int A[m];
struct S { int n, m; A a[2]; A b[] __attribute__((counted_by (n))); } *p;
p = __builtin_malloc (sizeof (struct S) + sizeof (A) * n);
p->n = n;
p->m = m;
__builtin_printf ("the bdos of pb is %u \n",__builtin_dynamic_object_size
(p->b, 1));
}
int main ()
{
foo (2, 10);
return 0;
}
compiled with the latest GCC, the bdos cannot return the correct value for the
object size of p->b.
/home/opc/Install/latest-d/bin/gcc -O1 t.c
the bdos of pb is 0
However, when change the above testing slightly to change the VLA to a regular
array:
void
foo (int n, int m)
{
typedef int A[10];
struct S { int n, m; A a[2]; A b[] __attribute__((counted_by (n))); } *p;
p = __builtin_malloc (sizeof (struct S) + sizeof (A) * n);
p->n = n;
p->m = m;
__builtin_printf ("the bdos of pb is %u \n",__builtin_dynamic_object_size
(p->b, 1));
}
int main ()
{
foo (2, 10);
return 0;
}
the bdos returned correct value:
/home/opc/Install/latest-d/bin/gcc -O1 t.c
the bdos of pb is 80
