[Bug fortran/40877] memory leaks with gfc_charlen?

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

------- Comment #2 from janus at gcc dot gnu dot org  2009-08-05 11:27 -------
(In reply to comment #1)
>  * trans-decl.c (create_function_arglist)
> 
> This is OK - the new cl is threaded into the list.

Actually I think that this is not done properly. The code in question is:

              gfc_charlen *cl, *cl2;
              cl = f->sym->ts.cl;
              f->sym->ts.cl = gfc_get_charlen();
              f->sym->ts.cl->length = cl->length;
              f->sym->ts.cl->backend_decl = cl->backend_decl;
              f->sym->ts.cl->length_from_typespec = cl->length_from_typespec;
              f->sym->ts.cl->resolved = cl->resolved;
              cl2 = f->sym->ts.cl->next;
              f->sym->ts.cl->next = cl;
              cl->next = cl2;

First problem: cl2 is always NULL, since f->sym->ts.cl gets assigned a fresh
gfc_charlen.

Second problem: The new charlen is inserted in front of the old one, and not
behind it.

Let's say before this code is executed we have a linked list of charlen
structures like this:

something -> cl -> ...

After the code is executed this will look like:

something---
           |
new_cl -> cl -> NULL

where 'something' still points to 'cl', so 'new_cl' is not reachable from
within the linked list (and also cl->next is lost).


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40877