[Bug fortran/57762] [4.9 Regression] Memory leak in gfortran.dg/class_array_7.f03 after revision 200084

["burnus at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57762

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |burnus at gcc dot gnu.org

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> ---
If it makes you happy, the following plugs the memory leak:

--- a/gcc/testsuite/gfortran.dg/class_array_7.f03
+++ b/gcc/testsuite/gfortran.dg/class_array_7.f03
@@ -56,2 +56,3 @@ program main
   if (trim (print_type ("a", a)) .ne. "a is base_type") call abort
+  deallocate (a)
 end program main


The reason is that gfortran no longer automatically deallocates allocatables at
the end of the main program (with very few exceptions). That's in order to
prevent finalization.

Fortran 2008 has:
"A variable, common block, or procedure pointer declared in the scoping unit of
a main program, module, or submodule implicitly has the SAVE attribute, which
may be conrmed by explicit specification."

And:
"4.5.6.3 When finalization occurs":

"A nonpointer, nonallocatable object that is not a dummy argument or function
result is finalized immediately before it would become undened due to
execution of a RETURN or END statement (16.6.6, item (3))."

which excludes SAVE:
"(3) When execution of an instance of a subprogram completes,
     (a) its unsaved local variables become undefined,"

Okay, that was for nonallocatables - and we have an allocatable. But there the
same applies:
"When an allocatable entity is deallocated, it is finalized."
and
"When the execution of a procedure is terminated by execution of a RETURN or
END statement, an unsaved allocatable local variable of the procedure retains
its allocation and definition status if it is a function result variable or a
subobject thereof; otherwise, it is deallocated."


Before finalization entered the game, it was undetectable - within the program
- whether the compiler deallocated variables in the main program or not. Now,
it is no longer. Hence, there is no automatic deallocation - and you see the
memory leak.

See also  http://gcc.gnu.org/wiki/GFortran#GCC4.9