------- Comment #15 from Tobias dot Schlueter at physik dot uni-muenchen dot de
2007-11-09 12:44 -------
Subject: Re: gfortran excessive memory usage with COMMON
blocks in modules
fxcoudert at gcc dot gnu dot org wrote:
> Because in that case, mod2.mod already has two copies of the common:
>
> (('mpipriv' 2 0 0 'mpipriv') ('mpipriv' 2 0 0 'mpipriv'))
>
> and I don't think that's desirable. I think that the module loading is
> actually
> wrong here: the code in gfc_get_common (match.c) takes special care to
> duplicate this common name by creating a unique name for it. While I believe
> that mangling is necessary, the mangled name shouldn't be unique but simply
> prefixed, so that of the same name are merged, while prevented to clash with
> the namespace of the use'ing procedure.
I wrote this code originally, and I agree with your analysis.
> Index: match.c
> ===================================================================
> --- match.c (revision 129869)
> +++ match.c (working copy)
> @@ -2608,23 +2608,19 @@ gfc_common_head *
> gfc_get_common (const char *name, int from_module)
> {
> gfc_symtree *st;
> - static int serial = 0;
> - char mangled_name[GFC_MAX_SYMBOL_LEN + 1];
> + char mangled_name[GFC_MAX_SYMBOL_LEN + 12];
Should be + 13 (need one char for '\0').
> + /* A use associated common block is only needed to correctly layout
> + the variables it contains. */
> + snprintf (mangled_name, GFC_MAX_SYMBOL_LEN, "_frommodule_%s", name);
GFC_MAX_SYMBOL_LEN + 12, otherwise you could create ambiguities with
really long common names. Previously this wasn't possible due to the
serial number.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30285
