[coreboot] [PATCH]Include headers instead of sources in romstage, part 1/many

Kevin O'Connor kevin at koconnor.net
Sat May 8 17:56:46 CEST 2010

On Sat, May 08, 2010 at 10:34:23AM +0200, Patrick Georgi wrote:
> Am Samstag, den 08.05.2010, 10:25 +0200 schrieb Stefan Reinauer:
> > On 5/8/10 12:13 AM, Patrick Georgi wrote:
> > > -#initobj-y += serial.o
> > > +initobj-$(CONFIG_USE_DCACHE_RAM) += serial.o
> > >  subdirs-y += vga
> > Awesome... the less .c file includes we have in romstage.c the better..
> > 
> > This way works in the case of converting code that was previously always
> > compiled in.
> > 
> > But how should we handle things in case of other conditions?
> We could stuff all of the initobjs into an initobj.a, and use that for
> linking. ld will only pick up the object files that are actually needed
> then. This means we probably compile a serial port thingy too many, but
> they're rather small.

I think coreboot should try to avoid using .a files.

The latest version of gcc (v4.5) contains the -flto feature.  This can
provide significant benefits to coreboot code generation because it
allows the entire romstage (and ramstage) to be analyzed as a whole.
The resulting binaries are significantly smaller because unused code
can be eliminated and more functions can be inlined.  Unfortunately,
the standard linker can't handle -flto with .a files.


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