Re: [PATCH 3/3] lto-plugin: implement LDPT_GET_API_VERSION

[Richard Biener <richard.guenther@gmail.com>]

On Tue, Jul 12, 2022 at 1:50 PM Rui Ueyama <rui314@gmail.com> wrote:
>
> I'm fine, though I don't think I have a right to sign off.
>
> On Tue, Jul 12, 2022 at 3:36 PM Martin Liška <mliska@suse.cz> wrote:
> >
> > On 7/12/22 08:28, Richard Biener wrote:
> > > On Mon, Jul 11, 2022 at 6:35 PM Alexander Monakov <amonakov@ispras.ru> wrote:
> > >>
> > >> On Mon, 11 Jul 2022, Martin Liška wrote:
> > >>
> > >>> I've clarified that linker should return a value that is in range
> > >>> [minimal_api_supported, maximal_api_supported] and added an abort
> > >>> if it's not the case.
> > >>
> > >> I noticed that we are placing a trap for C++ consumers such as mold
> > >> by passing min/max_api_supported as enum values. Unlike C, C++ disallows
> > >> out-of-range enum values, so when mold does
> > >>
> > >> enum PluginLinkerAPIVersion {
> > >>   LAPI_V0 = 0,
> > >>   LAPI_V1,
> > >> };
> > >>
> > >> get_api_version(const char *plugin_identifier,
> > >>                 unsigned plugin_version,
> > >>                 PluginLinkerAPIVersion minimal_api_supported,
> > >>                 PluginLinkerAPIVersion maximal_api_supported,
> > >>                 const char **linker_identifier,
> > >>                 const char **linker_version) {
> > >>
> > >> checks such as 'min_api_supported > LAPI_V1' can be optimized out. Also,
> > >> if a future tool passes LAPI_V2, it will trigger Clang's UBSan (GCC
> > >> -fsanitize-undefined=enum instruments loads but not retrieval of function
> > >> arguments).
> > >>
> > >> I'd suggest to fix this on both sides by changing the arguments to plain
> > >> integer types.
> > >
> > > That's a good point - the enum itself is then also somewhat redundant
> > > if it just specifies symbolic names for 0, 1, ... but we can keep it for
> > > documentation purposes.
> >
> > All right, here we go with the integer types.
> >
> > May I install the version now?

OK.

Thanks,
Richard.

> > Thanks,
> > Martin
> >
> > >
> > >>
> > >> Alexander