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> BOOL a, b:
> a := FALSE
> b := FALSE
> WHILE TRUE
> INT v1:
> a & c1 ? v1
> INT v2:
> b & c2 ? v2
> Does KRoC detect this error at compile-time?
> SPoC sees it at run-time. It writes "Deadlock, #no stopped processes"
> to stderr on return from Scheduler, in main.
> Isn't it "required" to handle this by the compiler or at run-time
> already when the ALT is set up?
The toolset compiler appears to generate a CCNT1 instruction,
presumably to check that at least one of the pre-conditions is
KRoC for linux produces the following (with debugging on):
KRoC: Range error on operation CCNT1 in PROC "selfdead"
in file "selfdead.occ" near line 15
Line 15 is where "b & c2 ? v2" lives. Although the error message
isn't too helpful, it at least detects it. So, the error isn't
detected at compile-time, but is at run-time. An optimiser (when
it gets written) would be able to detect it at compile-time.
Fred Barnes, PhD research student, UKC. http://nuked.xylene.com/