[Bug ipa/116410] modref doesn't generate LTO summaries with -ffat-lto-objects (-ffat-lto-objects generates different and inefficient code compared with -fno-fat-lto-objects)

[hubicka at ucw dot cz via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116410

--- Comment #11 from Jan Hubicka <hubicka at ucw dot cz> ---
> We plan to adopt -ffat-lto-objects ourselves soon for at least a subset of
> packages, so this was good timing. :)
Note that -ffat-lto-objects has various issues, especially with library
archives.  The problem is that fat LTO object has two symbol tables (one
ELF and one LTO) but ar and other utilities does not handle this and
will pick one of the two symbol tables. In the case the symbol LTO and
non-LTO symbol tables diverge, surprises happens.
HJ had binutils patch solving this, but AFAIK it was not merged in.

Honza