[Bug fortran/98141] New: Segmentation fault with empty string sourced allocation
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.
[Bug fortran/98141] Segmentation fault with empty string sourced allocation
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98141 --- Comment #1 from David Neill Asanza --- Here are even shorter examples: $ cat short01.f90 program short01 class(*), allocatable :: a, b, c character(len=0) :: s allocate(a, source=s) !! No problem allocate(character(len=0)::b) allocate(c, source=b) !! Segfault end program $ cat short02.f90 program short02 class(*), allocatable :: a, b allocate(a, source='') !! No problem allocate(b, source=a) !! Segfault end program So it seems the underlying issue is the sourced allocation from a 0-length unlimited polymorphic type.
[Bug fortran/98573] New: Dynamic type lost on assignment
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98573
Bug ID: 98573
Summary: Dynamic type lost on assignment
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: ---
Created attachment 49904
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49904&action=edit
Minimal reproducer
In the following example, the dynamic type of an unlimited polymorphic array is
lost on an assignment but conserved (as expected) on a sourced allocation.
This happens in all versions I've tried: 7.5.0, 8.4.0, 9.3.0, 10.2.0
My system is Ubuntu 20.04 on Intel hardware with all gfortran versions
installed directly from the Ubuntu repositories.
$ cat type_lost.f90
module foo
type, public:: box
class(*), allocatable :: val(:)
end type
contains
subroutine store1(this, val)
class(box), intent(out) :: this
class(*), intent(in) :: val(:)
this%val = val
end subroutine store1
subroutine store2(this, val)
class(box), intent(out) :: this
class(*), intent(in) :: val(:)
allocate(this%val, source=val)
end subroutine store2
subroutine vector_type(val)
class(*), intent(in) :: val(:)
select type (val)
type is (integer)
print '("INTEGER")'
class default
print '("OTHER")'
end select
end subroutine vector_type
end module foo
program prog
use foo
type(box) :: b
call store1(b, [1, 2, 3])
call vector_type(b%val) ! OTHER
call store2(b, [1, 2, 3])
call vector_type(b%val) ! INTEGER
end program
$ gfortran -g -Wall -Wextra minimal.f90
$ ./a.out
OTHER
INTEGER
[Bug fortran/98573] Dynamic type lost on assignment
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98573 --- Comment #1 from David Neill Asanza --- Removing the derived type container triggers a segfault. $ cat segfault.f90 module foo contains subroutine store1(arr, val) class(*), allocatable, intent(out) :: arr(:) class(*), intent(in) :: val(:) arr = val end subroutine store1 subroutine store2(arr, val) class(*), allocatable, intent(out) :: arr(:) class(*), intent(in) :: val(:) allocate(arr, source=val) end subroutine store2 end module foo program prog use foo class(*), allocatable :: arr(:) call store1(arr, [1, 2, 3]) ! SEGFAULT call store2(arr, [1, 2, 3]) ! NO PROBLEM end program $ gfortran -g -Wall -Wextra minimal.f90 $ ./a.out Program received signal SIGSEGV: Segmentation fault - invalid memory reference.
[Bug fortran/98573] Dynamic type lost on assignment
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98573 --- Comment #2 from David Neill Asanza --- Created attachment 49905 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49905&action=edit Minimal reproducer for segmentation fault.
[Bug fortran/98573] Dynamic type lost on assignment
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98573
--- Comment #3 from David Neill Asanza ---
A related case when the array is 0-length. In this case, the dynamic type is
lost in both assignment and sourced allocation.
$ cat type_lost_0_length.f90
module foo
type, public:: box
class(*), allocatable :: val(:)
end type
contains
subroutine store1(this, val)
class(box), intent(out) :: this
class(*), intent(in) :: val(:)
this%val = val
end subroutine store1
subroutine store2(this, val)
class(box), intent(out) :: this
class(*), intent(in) :: val(:)
allocate(this%val, source=val)
end subroutine store2
subroutine vector_type(val)
class(*), intent(in) :: val(:)
select type (val)
type is (integer)
print '("INTEGER")'
class default
print '("OTHER")'
end select
end subroutine vector_type
end module foo
program prog
use foo
type(box) :: b
integer, allocatable :: arr1(:)
integer, dimension(0) :: arr2
allocate(arr1(0))
call store1(b, arr1)
call vector_type(b%val) ! OTHER
call store2(b, arr1)
call vector_type(b%val) ! OTHER
call store1(b, arr2)
call vector_type(b%val) ! OTHER
call store2(b, arr2)
call vector_type(b%val) ! OTHER
end program
$ gfortran -g -Wall -Wextra type_lost_0_length.f90
$ ./a.out
OTHER
OTHER
OTHER
OTHER
[Bug fortran/98573] Dynamic type lost on assignment
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98573 --- Comment #4 from David Neill Asanza --- Created attachment 49906 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49906&action=edit Reproducer for 0-length case.
[Bug fortran/98573] Dynamic type lost on assignment
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98573 --- Comment #6 from David Neill Asanza --- Thanks for looking into this Paul. I'm looking forward to having this fixed. :)
