On Fri, Jul 24, 2015 at 15:26:38 -0400, Nathan Sidwell wrote:
> this version makes the following changes to the earlier version.
>
> *) Renames things to FOO_ver, rather than FOO_2
>
> *) No attempt to deal with cross-version plugins and libgomp.
>
> *) Adds GOMP_OFFLOAD_version function to plugin. (I went with your
> approach). Returns the GOMP_VERSION used to build the plugin, which
> libgomp checks matches the value for its build. When we make
> incompatible changes to the plugin interface, that value can be
> incremented.
>
> *) While working on gomp_load_plugin_for_device, I noticed the DLSYM
> and DLSYM_OPT macros were somewhat funky. We're loading functions,
> so don't expect a NULL value. We can simply check the returned
> value and only need dlerror when we get NULL. The counting that
> DLSYM_OPT does was somewhat funky too. IMHO better for that macro
> to simply return a truth value.
I do not know whether this is a good idea, but it's possible to add some magic
number into mkoffload:process () like:
865 fprintf (out, "static const void *target_data[] = {\n");
866 fprintf (out, " MAGIC, VERSION, ptx_code, (void*) %u, var_mappings,
(void*) %u, "
867 "func_mappings\n", nvars, nfuncs);
868 fprintf (out, "};\n\n");
So, libgomp will be able to check target_data in GOMP_offload_register.
If MAGIC is present, it can check the VERSION, the plugin also can check the
version in a similar way. This hack allows to avoid new versions of
GOMP_*_ver in libgomp and GOMP_OFFLOAD_*_ver in plugins.
-- Ilya
