[flang][debuginfo] Array with non constant extent is being treated as assumed size array.

[abidh]

The array with explicit shape with non constant extent is being treated as assumed size array. See the following program:

PROGRAM minimal
  integer arr(-2:3)
  arr(:) = 1
  print *, arr
  call change(arr, 6)
contains
  subroutine change(a, n)
    integer :: a(n)
    a(1) = 10
    print *, a
  end subroutine change
end

When stopped in subroutine change, the type of a is shown as follows:

(gdb) ptype a
type = integer (*)
(gdb) p a
$1 = <error reading variable: failed to get range bounds>

With correct debug information, it should be possible to get the extent of this array.

[llvmbot]

@llvm/issue-subscribers-debuginfo

Author: Abid Qadeer (abidh)

The array with explicit shape with non constant extent is being treated as assumed size array. See the following program:

PROGRAM minimal
  integer arr(-2:3)
  arr(:) = 1
  print *, arr
  call change(arr, 6)
contains
  subroutine change(a, n)
    integer :: a(n)
    a(1) = 10
    print *, a
  end subroutine change
end

When stopped in subroutine change, the type of a is shown as follows:

(gdb) ptype a
type = integer (*)
(gdb) p a
$1 = <error reading variable: failed to get range bounds>

With correct debug information, it should be possible to get the extent of this array.

[llvmbot]

@llvm/issue-subscribers-flang-ir

Author: Abid Qadeer (abidh)

The array with explicit shape with non constant extent is being treated as assumed size array. See the following program:

PROGRAM minimal
  integer arr(-2:3)
  arr(:) = 1
  print *, arr
  call change(arr, 6)
contains
  subroutine change(a, n)
    integer :: a(n)
    a(1) = 10
    print *, a
  end subroutine change
end

When stopped in subroutine change, the type of a is shown as follows:

(gdb) ptype a
type = integer (*)
(gdb) p a
$1 = <error reading variable: failed to get range bounds>

With correct debug information, it should be possible to get the extent of this array.

[pawosm-arm]

One more example exposing the same issue:

program test
  implicit none
  integer, dimension(-2:2, -3:3), target :: storage2d
  integer, dimension(:, :), pointer :: pointer2d

  storage2d = -1
  pointer2d => storage2d(-1:1, -2:2)
  pointer2d = -7
  call automatic2d(5, 7, storage2d)

contains

  subroutine automatic2d(x, y, arr)
    implicit none
    integer :: x
    integer :: y
    integer :: arr(x, y)

    print *, arr
end

end program

With the breakpoint at line 19 (print *, arr), gdb is unable to print the contents of the array when this program was compiled with flang-new (no such problem when compiled with gfortran):

(gdb) print arr
$1 = <error reading variable: failed to get range bounds>