https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100814
Bug ID: 100814
Summary: Fortran memory error on assignment from polymorphic
variable
Product: gcc
Version: 10.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: jhaiduce at gmail dot com
Target Milestone: ---
The following code produces a memory error when compiled with recent versions
of gfortran:
```
module distributed_array
implicit none
type :: darray_segment
integer::rank
integer::offset
integer::length
real(kind=8), allocatable::data(:)
contains
end type darray_segment
type :: darray
type(darray_segment), allocatable::segments(:)
end type darray
contains
function new_darray(segments)
class(darray_segment), intent(in)::segments(:)
type(darray)::new_darray
new_darray%segments = segments
end function new_darray
end module distributed_array
program test_darray
use distributed_array, ONLY: darray, darray_segment, new_darray
implicit none
integer, parameter::np_src = 4
integer, parameter::np_dest = 3
type(darray)::src_darray
type(darray)::dest_darray
type(darray_segment)::src_segments(np_src)
type(darray_segment)::dest_segments(np_dest)
src_darray = new_darray(src_segments)
dest_darray = new_darray(dest_segments)
end program test_darray
```
The above code runs without error when compiled with gfortran 4.9.4 and 10.2,
but when compiled with gfortran 10.3 and 11.1 it produces the following output:
```
darray_test: malloc.c:2385: sysmalloc: Assertion `(old_top == initial_top (av)
&& old_size == 0) || ((unsigned long) (old_size) >= MINSIZE && prev_inuse
(old_top) && ((unsigned long) old_end & (pagesize - 1)) == 0)' failed.
Program received signal SIGABRT: Process abort signal.
Backtrace for this error:
#0 0x7f727c59fbf0 in ???
#1 0x7f727c59ee45 in ???
#2 0x7f727c20d83f in ???
at
/build/glibc-vjB4T1/glibc-2.28/signal/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:0
#3 0x7f727c20d7bb in __GI_raise
at ../sysdeps/unix/sysv/linux/raise.c:51
#4 0x7f727c1f8534 in __GI_abort
at /build/glibc-vjB4T1/glibc-2.28/stdlib/abort.c:79
#5 0x7f727c255a67 in __malloc_assert
at /build/glibc-vjB4T1/glibc-2.28/malloc/malloc.c:298
#6 0x7f727c257e6e in sysmalloc
at /build/glibc-vjB4T1/glibc-2.28/malloc/malloc.c:2382
#7 0x7f727c2592c8 in _int_malloc
at /build/glibc-vjB4T1/glibc-2.28/malloc/malloc.c:4133
#8 0x7f727c25a3e2 in __GI___libc_malloc
at /build/glibc-vjB4T1/glibc-2.28/malloc/malloc.c:3049
#9 0x401f10 in __distributed_array_MOD_new_darray
at /test/src/test/darray_tests.F90:23
#10 0x402933 in test_darray
at /test/src/test/darray_tests.F90:44
#11 0x402aaf in main
at /test/src/test/darray_tests.F90:31
```
The code also runs without error when compiled with ifort 2021.2.
The problem appears to be triggered by the assignment `new_darray%segments =
segments`. The error can be prevented by changing the declaration
`class(darray_segment), intent(in)::segments(:)` to `type(darray_segment),
intent(in)::segments(:)` (replacing class with type), or by replacing the
assignment with an explicit allocation: `allocate( new_darray%segments, source=
segments )`.
