Before, the ODD offsets (for indexing into the reachable states) were
stored as longs, resulting in inconsistent numbers of (symbolic)
states that can be treated. In particular, on Win64, long is 32bit.
We switch to int64_t for the ODD offsets everywhere, allowing
MTBDD computations for models with >2^31 states.
Additionally, we check for arithmetic overflow in the offset
computations. Due to the symbolic storage for the models and the
state space explosion, it's possible to construct simple model files
that reach the 2^63 states limit.
If this limit is reached, we now throw an error message. In the future
it might be worthwile to ensure that PRISM can deal with the absence
of an ODD for all the computations that don't absolutely require it
and carry on (most MTBDD engine algorithms should be fine).
git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@12019 bbc10eb1-c90d-0410-af57-cb519fbb1720