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Re: compatibility of structs/unions/enums in the middle end
On Wed, Oct 2, 2019 at 8:24 PM Uecker, Martin
<Martin.Uecker@med.uni-goettingen.de> wrote:
>
> Am Mittwoch, den 02.10.2019, 17:37 +0200 schrieb Richard Biener:
> > On October 2, 2019 3:55:43 PM GMT+02:00, "Uecker, Martin" <Martin.Uecker@med.uni-goettingen.de>
> > wrote:
> > > Am Mittwoch, den 02.10.2019, 15:12 +0200 schrieb Richard Biener:
> > > > On Wed, Oct 2, 2019 at 3:10 PM Richard Biener
> > > > <richard.guenther@gmail.com> wrote:
> > > > >
> ...
>
> > > > Oh, and LTO does _not_ merge types declared inside a function,
> > > > so
> > > >
> > > > void foo () { struct S { int i; }; }
> > > > void bar () { struct S { int i; }; }
> > > >
> > > > the two S are distinct and objects of that type do not conflict.
> > >
> > > This is surprising as these types are compatible across TUs. So
> > > if some pointer is passed between these functions this is
> > > supposed to work.
> >
> > So if they are compatible the frontend needs to mark them so in this case.
>
> It can't. The front end never sees the other TU.
If the type "leaves" the CU via a call the called function has a prototype
through which it "sees" the CU.
Richard.
> Best,
> Martin