Dear all,
during the GCC Gathering I realized during the LTO debugging symbol
discussion that gfortran does not generate debug information for the OOP
features (cf. PR 49475).
The first issue to solve is which DWARF information one should generate.
I have only very limited knowledge of DWARF, except that I quickly
scanned "5.5.3 Derived or Extended Structs, Classes and Interfaces" and
"5.5.7 Member Function Entries" (of http://www.dwarfstd.org/doc/DWARF4.pdf).
I think one should handle member functions (cf. example below). I am not
sure whether other things like type extension or accessibility should be
handled.
Tobias
! Example
module m
implicit none
type parent
integer :: var_p = 3
contains
procedure, nopass :: memb => proc_parent
end type parent
! Side note: nopass disables passing of the type itself ("this")
! Otherwise, the effective type would be passed as first argument to
! proc_parent
type, extends(parent) :: child
contains
procedure, nopass :: memb => proc_child
end type child
contains
subroutine proc_parent()
print *, "proc_parent"
end subroutine proc_parent
subroutine proc_child()
print *, "proc_child"
end subroutine proc_child
end module m
program main
use m
implicit none
class(parent), allocatable :: a
type(child) :: b
allocate (parent :: a)
call a%memb() ! Uses vtable to see that proc_parent should be called
deallocate (a)
allocate (child :: a)
call a%memb() ! Uses vtable to see that proc_child should be called
! Variable access - resolved at compile time
print *, b%var_p ! Directly access "var_p"
print *, b%parent%var_p ! Access it via the parent type
end program main
