[Patch, fortran, pr59678, v1] -- [F03] Segfault on equalizing variables of a complex derived type

[Andre Vehreschild]

Hi all,

this patch fixes a deep copy issue, when allocatable components of an entity
were not allocated. Before the patch the deep copy was run without
checking if the component is actually allocated and the program crashed because
a null pointer was dereferenced. Furthermore, was the code to copy a structure
component not checking the correct ref to determine whether a component was
allocated, when allocatable components were nested. Example:

type InnerT
  integer, allocatable :: inner_I
end type
type T
  type(InnerT), allocatable :: in
end type

The pseudo pseudo code generated for this was something like:

subroutine copy(src,dst)
  dst = src
  if (allocated (src.in.inner_I)) // crash
    allocate (dst.in)
  end if

  dst.in.inner_I = src.in.inner_I // crash
end subroutine

The patch fixes this by generating:

subroutine copy(src,dst)
  dst = src
  if (allocated (src.in))
    allocate (dst.in)
    dst.in= src.in
    if (allocated (src.in.inner_I))
      allocate (dst.in.inner_I)
      dst.in.inner_I = src.in.inner_I
    end
  end
end subroutine

Of course is this pseudo pseudo code shortened dramatically to show just the
necessary bits.

Bootstraps and regtests ok on x86_64-linux-gnu/F21.

Ok, for trunk?

Thanks to Dominique for identifying the pr addressed by this patch.

Regards,
	Andre
-- 
Andre Vehreschild * Email: vehre ad gmx dot de 
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