https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64230
janus at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |wrong-code
CC| |janus at gcc dot gnu.org
--- Comment #2 from janus at gcc dot gnu.org ---
Here is a somewhat reduced test case, which gets rid of parts of the insane
inheritance chain:
Program main
Implicit None
Type :: t1
End Type
Type, Extends (t1) :: t2
Integer, Allocatable :: i
End Type
Type, Extends (t2) :: t3
Integer, Allocatable :: j
End Type
Class (t1), Allocatable :: t
Allocate (t3 :: t)
print *,"allocated!"
Deallocate (t)
End
$ gfortran-5.0 -g -fsanitize=undefined c0.f90 && ./a.out
allocated!
c0.f90:1: runtime error: member access within null pointer of type 'struct t2'
Program received signal SIGSEGV: Segmentation fault - invalid memory reference.
Backtrace for this error:
#0 0x7FC890D235F7
#1 0x7FC890D23C3E
#2 0x7FC88F557D9F
#3 0x402423 in __final_main_T2 at c0.f90:1 (discriminator 12)
#4 0x4015B1 in __final_main_T3 at c0.f90:1 (discriminator 8)
#5 0x401806 in MAIN__ at c0.f90:14 (discriminator 3)
Speicherzugriffsfehler (Speicherabzug geschrieben)
The segfault obviously happens in the deallocate statement, for which
-fdump-tree-original shows the following translation:
if (t._data == 0B)
{
_gfortran_runtime_error_at (...);
}
else
{
if (t._vptr->_final != 0B)
{
{
struct array0_t1 desc.13;
desc.13.dtype = 40;
desc.13.data = (void * restrict) t._data;
t._vptr->_final (&desc.13, t._vptr->_size, 0);
}
}
__builtin_free ((void *) t._data);
}
t._data = 0B;
(struct __vtype_main_T1 *) t._vptr = &__vtab_main_T1;
So, yeah, the problem is somewhere in the finalizer call ("t._vptr->_final"),
but I don't directly see where in the finalization routine it occurs (the
compiler generates a 500+ line dump for a 15-line program here).
