RFC: PowerPC bsp_specs Clean Up Question

Chris Johns chrisj at rtems.org
Thu Dec 21 21:03:34 UTC 2017


On 22/12/2017 02:01, Joel Sherrill wrote:
> I'm not opposed to this but it requires even more delicate editing that I can't
> easily test. 

If something breaks and it is reported we can look at fixing it. If something
breaks and it is not reported is it broken? ;)

> We can get rid of bsp_specs and do this largely at the same time. The
> specifications in GCC will have to be tinkered with to address what's left in
> bsp_specs so the specs can do this. 

I think GCC's default configuration should be user focused and not BSP or
internally RTEMS focused. I see this meaning GCC's model is the same for all
BSPs and the options to access a BSP are similar.

> But I haven't figured out precisely what to do with gcc at this point.

The difficult part is locating start.o and similar object files. RTEMS currently
implements a horrible hack using -B. This option not only locates a bsp_specs
file it also adds a search path for locating .o and other files. I have only
just uncovered this as part of removing preinstall and it is a horrible problem
to solve. For example what happens if I create start.o in my application and
provide it on the command line to the linker with a -B to the location RTEMS's
start.o is located? Does GCC know what I want, is this option order dependent or
something else? A simple solution here is use RTEMS specific names but the idea
of needing -B seems wrong.

Chris



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