[patch,testsuite,avr]: Filter-out -mmcu= from options for tests that set -mmcu=

Georg-Johann Lay avr@gjlay.de
Fri Dec 2 10:21:00 GMT 2016

On 01.12.2016 17:40, Mike Stump wrote:
> On Dec 1, 2016, at 3:54 AM, Georg-Johann Lay <avr@gjlay.de> wrote:
>> This patch moves the compile tests that have a hard coded -mmcu=MCU in their dg-options to a new folder.
>> The exp driver filters out -mmcu= from the command line options that are provided by, say, board description files or --tool-opts.
>> This is needed because otherwise conflicting -mmcu= will FAIL respective test cases because of "specified option '-mmcu' more than once" errors from avr-gcc.
>> Ok for trunk?
> So, it would be nice if different ports can use roughly similar schemes to handle the same problems.  I think arm is one of the more complex ports at this point in this regard with a lot of people and a lot of years time to contemplate and implement solutions to the problem.  They in particular don't have to move test cases around to handle the difference like this, I think it would be best to avoid that requirement if possible.
> Glancing around, two starting points for how the arm achieves what it does:
>   lappend dg_runtest_extra_prunes "warning: switch -m(cpu|arch)=.* conflicts with -m(cpu|arch)=.* switch"
> in arm.exp, and they use something like:
> /* { dg-require-effective-target arm_crypto_ok } */                                                 |crypto-vsha256hq_u32.c:2:/* { dg-require-effective-target arm_crypto_ok } */
> /* { dg-add-options arm_crypto } */                                                                 |crypto-vsha256su0q_u32.c:2:/* { dg-require-effective-target arm_crypto_ok } */
> to validate the requirements of the test case, and to ensure that
> optional things are selected.  Nice, simple, extensible, handles
> multilibs, dejagnu arguments and different cpu defaults as I recall.
> You won't need all the hair the arm folks have, but if you stub in
> support in that direction, you then have simple, easy expansion room
> to match all complexities that the arm folks have already hit and
> solved.

I tried this approach, but it does not work as expected.

Notice that avr-gcc throws an error if conflicting -mmcu options are 
supplied.  Pruning the output will make some tests "PASS", but the 
compiler didn't actually do anything but producing an error message...

And one test FAILs because it should produce some specific diagnostic, 
but again the compiler just throws a different error, the output is 
pruned and the expected message is missing, hence fail.

Also one test case is for ATmega8, but you won't run the whole test 
suite against ATmega8 because that device is too restricted to give 
reasonable results...  Hence for some tests -mmcu=atmega8 is added by hand.


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