http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56008
Tobias Burnus <burnus at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Keywords| |wrong-code
Last reconfirmed| |2013-01-16
CC| |burnus at gcc dot gnu.org,
| |pault at gcc dot gnu.org
Ever Confirmed|0 |1
Summary|[F03] lhs-allocation |[F03] wrong code with
|invoking the |lhs-realloc on assignment
|array-constructor on DDTs |with derived types having
|causes memory error |allocatable components
--- Comment #3 from Tobias Burnus <burnus at gcc dot gnu.org> 2013-01-16
22:50:40 UTC ---
Seems to be similar to PR 47517.
(In reply to comment #0)
> (Btw. what is the appropriate Fortran expression/terminology for DDT
> member-variables)
"components". (Besides data and procedure-pointer components, a derived type
can also contain type-bound procedures.)
(In reply to comment #2)
> Created attachment 29185 [details]
> valgrind -v --track-origins=yes ./a.out
Two side remarks:
a) GCC 4.8 ships with -fsanitize=address,thread - and "address" ("ASAN")
roughly matches valgrind. Cf. http://gcc.gnu.org/gcc-4.8/changes.html - Though,
for that example, it doesn't seem to work. On the other hand, for stack-memory
issues, valgrind doesn't work and while ASAN might.
b) To track what goes wrong, one can also look at a C-like dump of the internal
representation using -fdump-tree-original (-fdump-tree-all, ...)
For:
conc = [ xx, yy ]
one gets the following -ftree-dump-original:
conc.data = (void * restrict) __builtin_malloc (96);
...
if ((void *) (*(struct test_typ[2] * restrict)
atmp.6.data)[S.9].a.data != 0B)
Either we have to use calloc instead of malloc - or we have to modify the
intrinsic assignment to assume unallocated memory in this case. In terms of
performance, the latter would be better. Using "calloc" is the quicker fix.
Side note 2: If one uses the GLIBC (i.e. Linux) and has MALLOC_PERTURB_ set,*
one gets a segfault when one tries to run the code. [MALLOC_PERTURB_ sets the
value returned by "malloc" to non-NUL.] (* e.g. "export
MALLOC_PERTURB_=$(($RANDOM % 255 + 1))")
