http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49324
--- Comment #9 from Tobias Burnus <burnus at gcc dot gnu.org> 2011-06-14
13:07:07 UTC ---
(Comment fixed 8 fixed the missing deep copy.)
Regarding the reallocate (cf. comment 6, but using scalars to reduce the dump
size): For
type t
integer, allocatable :: A
end type t
type(t), allocatable :: z
...
z = [ x ]
One gets the following dump:
/* If not initialized. For arrays: Also realloc, if the size is wrong. */
if (z != 0B) goto L.1;
z = (struct t *) __builtin_malloc (8);
So far so good, but one then has
D.1552 = *z;
if (D.1552.a != 0B)
__builtin_free ((void *) D.1552.a);
which is only OK if "z.data" has neither been just allocated nor reallocated.
If it has, there are two problems: (a) The old memory is not freed. (b) if
malloc/realloc does not return nullified memory, free() operates on some random
pointer.
The question is how to handle it best? The assignment is handled in
gfc_trans_assignment_1, which calls gfc_alloc_allocatable_for_assignment for
the realloc and gfc_trans_scalar_assign for the assignment.
