Re: [edk2-devel] [PATCH] OvmfPkg/PlatformCI: Skip GCC5_OVMF_IA32X64_FULL_NOOPT build

["Pedro Falcato" <pedro.falcato@gmail.com>]

On Wed, Jun 21, 2023 at 8:55 AM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
> On Wed, Jun 21, 2023 at 01:40:06AM +0100, Pedro Falcato wrote:
> > On Tue, 20 Jun 2023, 12:11 Li, Yi, <yi1.li@intel.com> wrote:
> >
> > > The effect of LTO is limited with optimization turned off, and blocked
> > > the upgrade of Openssl3.0. We already skipped this build with VS2019,
> > > skip the GCC NOOPT build also.
> > >
> > Hi,
> >
> > If LTO is the problem here, have you given ffunction-sections +
> > fdata-sections + gc-sections a spin?
>
> lto alone works and reduces size a bit, also turning on optimizations
> has a much bigger effect though.  Which I suspect happens because gcc
> detects constant expressions then, calculates them at compile time
> instead of runtime, which in turn removes function calls in code paths
> never taken.

Right, LTO is of course a lot less limited when it comes to this and
may give out further size reductions. But if we can't enable LTO (as
in NOOPT), gc-sections /may/ help here; gc-sections will *not* affect
debugging whatsoever.
Of course, whether this works is pure speculation; I personally
haven't tested this.

-- 
Pedro