[RFC PATCH u-boot 01/12] build: use thin archives instead of incremental linking

[Marek Behun]

On Thu, 4 Mar 2021 18:57:11 +0800
Bin Meng <bmeng.cn at gmail.com> wrote:

> Hi Marek,
> 
> On Wed, Mar 3, 2021 at 12:13 PM Marek Behún <marek.behun at nic.cz> wrote:
> >
> > Using thin archives instead of incremental linking
> > - saves disk space
> > - works better with dead code elimination
> > - prepares for potential LTO  
> 
> The commit message is a little bit confusing. This commit actually
> does 2 things: don't do incremental linking (using --whole-archive),
> and use thin archive (passing T to ar). I believe they are for
> different purposes, so we cannot say "using thin archives instead of
> incremental linking".
> > -       -Wl,--start-group $(patsubst $(obj)/%,%,$(u-boot-spl-main)) \
> > -       $(patsubst $(obj)/%,%,$(u-boot-spl-platdata)) -Wl,--end-group \
> > +       -Wl,--whole-archive $(patsubst $(obj)/%,%,$(u-boot-spl-main)) -Wl,--no-whole-archive \
> > +       -Wl,--start-group $(patsubst $(obj)/%,%,$(u-boot-spl-platdata)) -Wl,--end-group \  
> 
> u-boot-spl-platdata is still within --start-group, --end-group, is
> this intentional?

I confess that I did not really study these options, I have made these
changes according to old LTO patches for Linux. But you are right that
it does not make sense. I have fixed this for the next version of this
patch.

> Is P required to make everything work?

It is not. Removed in next version.