[Bug ada/60078] acats c761007 fails on ARM

[bernd.edlinger at hotmail dot de]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60078

--- Comment #13 from Bernd Edlinger <bernd.edlinger at hotmail dot de> ---
(In reply to charlet@adacore.com from comment #12)
> > could you explain, why the test fails when the delay is added to the
> > unmodified test case?
> 
> Sorry, I'm not following you here, I do not know which delay you would
> add where (and why).
> 
> Arno

I am here, because this test seems to fail on a Dual-Core ARM
running Linux version 3.7.0.

What it looks like for me, is this is executed on two cores in parallel:

   -- look to see if this character has been finalized yet
    for SEI in 1..Side_Effect_Finger loop
      Previous_Side_Effect := Previous_Side_Effect
                              or Side_Effect(Side_Effect_Finger) = I.Effect;
    end loop;

    -- if not, then tack it on to the string, and touch the character
    if not Previous_Side_Effect then
      Side_Effect_Finger := Side_Effect_Finger +1;
      Side_Effect(Side_Effect_Finger) := I.Effect;
      TCTouch.Touch(I.Effect);
    end if;

and both try to add "G" to Side_Effect. Both execute the for loop,
and both don't see each other, thus Previous_Side_Effect := False.
Then both enter the if statement, and end up with GGHIJ => test FAILED.

To make it reproducible, I added a delay 0.01 between for and if statement
and this made the test fail every time, even on X86_64.

If the test is OK as it is, then it is probably the responsibility
of the runtime to ony execute one Finalize method at the time?

So is it a bug in the Test Case or in the GNAT or on my hardware?


Bernd.