Re: Test with an lto-build of libgfortran.

[Thomas Koenig <tkoenig@netcologne.de>]

Hi Jakub,

> It is worse than that, usually the LTO format changes e.g. any time any
> option or parameter is added on a release branch (several times a year) and
> at other times as well.

Hm, that makes LTO not very well suited for libraries...

> Though, admittedly GCC is the single package that actually could get away
> with LTO in lib*.a libraries, at least in some packagings (if the static
> libraries are in gcc specific subdirectories rather than say /usr/lib{,64}
> or similar and if the packaging of gcc updates both the compiler and
> corresponding static libraries in a lock-step.  Because in that case LTO
> in there will be always used only by the same snapshot from the release
> branch and so should be compatible with the LTO in it.

Maybe another approach: Instead of storing version-dependent LTO code in
the *.a files, we could just store preprocessed C code there, somewhat
shortened by removing whitespace, comments and unused declarations
(and/or store them in compressed format).

This would also allow the something like sanitizers to look into the
runtime libraries, and other instrumentation.

It would also be a much more extensive project, also involving
modifications to the linker. Not sure how realistic that would be.

Best regards

	Thomas