SPARC-RTEMS5-GCC ignores or don't find libraries

[Joel Sherrill]

On Tue, Mar 26, 2019 at 7:13 PM William Busacker <wbusacker at outlook.com>
wrote:

> Michel,
>
> Maybe I can help you out.
>
> I personally find the default RTEMS makefile to be overly complicated for
> simple projects. I get why its made the way it is, but ¯\_(ツ)_/¯
>
> So the xxx-rtems5-gcc compiler doesn't have any knowledge of the actual
> RTEMS install. As far as I can tell, its just a fancy renamed target
> compiler. If you're trying to build an RTEMS project on its own, you'll
> need to tell the compiler where all of the headers and linker objects are
> at.
>

It does know a fair number of specifics about building and linking RTEMS
applications that you don't see at all. What you see is the arguments to
tell the tools where your BSP is and enable it.

I repeat.. a lot is implied by just using an RTEMS GCC. But the BSP is not
and that's "really RTEMS".

There is a post 5 clean up activity to eliminate the use of bsp_specs which
will drop some of the options. But something has to point to the BSP
install. Perhaps that can change to -rtems-bsp= or something. :)


> There's also a couple other details you'll need to tell the compiler
> about. I typically run with Raspberry Pis so for me in my Makefile the
> compiler command looks like
>
> arm-rtems5-gcc -B/$(RTEMS_INSTALL)/arm-rtems5/raspberrypi/lib -specs
> bsp_specs -qrtems -mcpu=arm1176jzf-s -o init.o init.c
>
> where $(RTEMS_INSTALL) is a path to where you ran ../rtems-git/configure.
> My build tree is kinda messed up so I don't know exactly where to point
> you, but if you manage to find the file "bsp_specs" that will be in the
> directory you need to target. My guess is that it would look something like
> sparc-rtems5/erc32/lib
>
> From there you just compile the project like you would a normal C program,
> just always substituting in sparc-rtems5-gcc for gcc and making sure that
> something like -B/$(RTEMS_INSTALL)/arm-rtems5/raspberrypi/lib -specs
> bsp_specs -qrtems -mcpu=arm1176jzf-s is in your compiler and linker flags.
> I think for you, you would need to change out the arm11.... for erc32, but
> I'm not sure. I think there's an RTEMS Source Builder program that can tell
> you what it needs to be. Joel or Chris would know.
>

My short cut is to look in rtems/bsps/CPU/BSP/config/BSP.cfg so
rtems/bsps/sparc/erc32/config/erc32.cfg.

There is an experiment pkgconfig *BSP.pc" installed with the BSP.

But it should be something like:

$(TARGET)-gcc -B$(RTEMS_INSTALL)/$(TARGET)/$(BSP)/lib -specs bsp_specs
-qrtems -mcpu=cypress

Where RTEMS_INSTALL is prefix, TARGET is sparc-rtems5 in this case, and BSP
is your erc32

The nice thing is that it is orthogonal across architectures. Swap those
out and change the BSP specific CPU CFLAGS. And boom... you're done.

And yes.. simplification of that line is a goal and challenge.

--joel



> Happy RTEMSing!
>
> -will
>
>
>
>
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