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Fixed findRepSolutions to work properly

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Previously, it was taking one lot of BK at a time, then checking to see if i and i' could overlap (i.e. i and i' were the array indexes to check), which of course they never could.  It now takes a list of BK to pair up against each other, and asks if 0 can overlap with 0, which it can as long as there is a solution to the replicators.
This commit is contained in:
Neil Brown 2009-02-07 19:07:10 +00:00
parent fdae05c3f3
commit 3701154a1b
1 changed files with 22 additions and 10 deletions
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32
checks/ArrayUsageCheck.hs
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@ -58,19 +58,31 @@ import Utils
type BK = [Map.Map Var [BackgroundKnowledge]]
type BK' = [Map.Map Var (EqualityProblem, InequalityProblem)]
-- | Given a list of replicators, and some background knowledge,
-- checks if there are any solutions for a combination of the normal replicator
-- constraints, and the given background knowledge.
-- Returns Nothing if no solutions, a String with a counter-example if there are solutions
findRepSolutions :: (CSMR m, MonadIO m) => [(A.Name, A.Replicator)] -> BK -> m (Maybe String)
findRepSolutions reps bk = case makeEquations (addReps $ ParItems $ map (\x -> SeqItems [(bk, [x], [])]) $
[A.ExprVariable (A.nameMeta n) $ A.Variable (A.nameMeta n) n
| (n, _) <- reps]) maxInt of
-- | Given a list of replicators, and a set of background knowledge for each
-- access inside the replicator, checks if there are any solutions for a
-- combination of the normal replicator constraints, and the given background
-- knowledge (pairing each set against each other, applying one set to the replicator,
-- and the other to the mirror of the replicator).
--
-- Returns Nothing if no solutions, a String with a counter-example if there
-- are solutions
findRepSolutions :: (CSMR m, MonadIO m) => [(A.Name, A.Replicator)] -> [BK] -> m (Maybe String)
findRepSolutions reps bks
-- To get the right comparison, we create a SeqItems with all the accesses
-- Because they are inside a PAR replicator, they will all get compared to each
-- other with one set of BK applied to i and one applied to i', but they will
-- never be compared to each other just with the constraints on i (which is not
-- what we are checking here). We set the dummy array accesses to all be zero,
-- which means they can overlap -- but only if there is also a solution to the
-- replicator background knowledge, which is what this function is trying to
-- determine.
= case makeEquations (addReps $ SeqItems [(bk, [makeConstant emptyMeta 0], [])
| bk <- bks]) maxInt of
Right problems -> do
probs <- formatProblems [(vm, prob) | (_,vm,prob) <- problems]
case mapMaybe solve problems of
[] -> return Nothing -- No solutions, safe
xs -> liftM (Just . concat) $ mapM format xs
xs -> liftM (Just . unlines) $ mapM format xs
res -> error $ "Unexpected reachability result"
where
maxInt = makeConstant emptyMeta $ fromInteger $ toInteger (maxBound :: Int32)
@ -144,7 +156,7 @@ checkArrayUsage (m,p) = mapM_ (checkIndexes m) $ Map.toList $
do sol <- formatSolution varMapping (getCounterEqs vm)
cx <- showCode (fst lx)
cy <- showCode (fst ly)
-- liftIO $ putStrLn $ "Found solution for problem: " ++ prob
-- liftIO $ putStrLn $ "Found solution for problem: " ++ probs
-- ++ show p
-- liftIO $ putStrLn $ "Succeeded on problem: " ++ prob
-- allProbs <- concatMapM (\(_,_,p) -> formatProblem varMapping p >>* (++ "\n#\n")) problems