[Bug lto/84213] [8 Regression] 521.wrf_r from SPEC 2017 fails to build (link) with LTO

["derodat at adacore dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84213

Pierre-Marie de Rodat <derodat at adacore dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |derodat at adacore dot com

--- Comment #7 from Pierre-Marie de Rodat <derodat at adacore dot com> ---
Hello,

(In reply to Richard Biener from comment #6)
> I'm quite sure the rev. is responsible for similar Ada -flto -g failures. 
> We simply may _not_ add location attributes early.

I did not have a deep look at this, so I’m asking: is it possible to add it
late, then?

> So I think we need to revert this patch and instead make sure those
> Ada variables do not get removed?  Like by marking them with
> DECL_PRESERVE_P?
> 
> Trying that (figuring where those decls are created).  Pierre-Marie,
> maybe you can help here as well.

IIRC, what my r248792 is about is not to preserve the DW_TAG_varible itself (it
was already present in the DWARF output before), but to make sure we have a
location for it: if we have a DW_TAG_variable entry without a DW_AT_location
attribute, GDB will consider that the variable does not exist and thus we’ll
loose debuggability in Ada.