https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98141
Bug ID: 98141
Summary: Segmentation fault with empty string sourced
allocation
Product: gcc
Version: 9.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: davidhneill at gmail dot com
Target Milestone: ---
The following example produces a segmentation fault on a sourced allocation
from the empty string to an unlimited polymorphic allocatable. This also
happens when the source is a 0-length character array instead of the empty
string literal.
The segfault is present in all versions I've tried: 7.5.0, 8.4.0, 9.3.0, 10.2.0
$ cat empty_string_segfault.f90
module foo
type, public :: any_scalar
class(*), allocatable :: value
contains
procedure :: alloc
end type
contains
subroutine alloc (this, value)
class(any_scalar), intent(out) :: this
class(*), intent(in) :: value
allocate(this%value, source=value)
end subroutine alloc
end module foo
program prog
use foo
type(any_scalar) :: s1, s2, s3
character(len=0) :: c
call s1%alloc(' ') !! No problem
call s2%alloc('') !! Segfault
call s3%alloc(c) !! Segfault
end program
$ gfortran -Wall -Wextra -g empty_string_segfault.f90
$ ./a.out
Program received signal SIGSEGV: Segmentation fault - invalid memory reference.
My system is Ubuntu 20.04 on Intel hardware with all gfortran versions
installed directly from the Ubuntu repositories.
