Many BSPs Fail to link CXX tests

[Joel Sherrill]

On Sun, Jan 3, 2016 at 8:26 PM, Chris Johns <chrisj at rtems.org> wrote:

> On 01/04/16 12:55, Joel Sherrill wrote:
>
>> On SPARC/SIS, the main lesson I learned is that if the executable
>> dropped to something ridiculously small, then something was broken. I
>> had one iteration where hello.exe had 48 bytes of code. :)
>>
>
> Nice work.
>
>
That much was pretty obvious. Why was a problem. :)

>
>> Any thoughts on how to catch breakages on BSPs we can only link?
>>
>>
> Can you get a suitable list of functions that must be present in the
> executable and check they are present with nm?
>
>
It should be simple if the breakage is between the entry point and the rest
of the BSP. If hello does not include bsp_start() or
rtems_initialize_data_structures(), then it is known to be broken. This is
what broke on sis -- the first 16 instructions of the start code had no
dependency on anything else. So the linkages were satisfied and nothing
else pulled in. :)


> I think this is a good thing to try to sweep in for 4.12 since we can
>> easily check 4.11 vs 4.12 for breakages on specific BSPs.
>>
>
> So this is a once only check and not something we always check for?
>
>
Should be one time only. If the linkage between the start code and C code
is correct, it will stay correct. Once you get to C code, everything should
be magically correct.

I think this is simple enough in principle where it could be written up as
a series of GCI tasks. One task per BSP given the amount of time. It isn't
much editing but I would want

(1) patch to make/custom/XXX.cfg

(2) the commit message to include:
    + base size for some tests like hello and ticker (same on all BSPs)
    + new size for the same tests

(3) Confirmation with hello.num posted to GCI task so we can see the
symbols ourselves. But they should have checked it.

OTOH, one of us could probably sweep the argument changes into the custom
files quickly, my build scripts capture the size of the tests already, and
we are used to scripting and automated passes.  Maybe I should play the
next couple of weeks. If someone wants to help, it would be nice to have
some.


> Chris
>
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