import Data.Maybe
import Control.Monad.State
import Control.Applicative
+import Control.Arrow
import JVM.ClassFile
import JVM.Converter
type AnalyseState = State BBState [OffIns]
+noException :: B.ByteString
+noException = B.empty
+
+emptyBasicBlock :: BasicBlock
+emptyBasicBlock = BasicBlock
+ { code = []
+ , exception = noException
+ , successor = Return }
+
printMapBB :: MapBB -> IO ()
printMapBB hmap = do
printfBb "BlockIDs: "
buildCFG xs = buildCFG' M.empty xs' xs'
where
xs' :: [OffIns]
- xs' = evalState (calculateInstructionOffset xs >>= markBackwardTargets) []
-
--- get already calculated jmp-targets and mark the predecessor of the
--- target-instruction as "FallThrough". we just care about backwards
--- jumps here (forward jumps are handled in buildCFG')
-markBackwardTargets :: [OffIns] -> AnalyseState
-markBackwardTargets [] = return []
-markBackwardTargets (x:[]) = return [x]
-markBackwardTargets (x@(x_off,x_bbend,x_ins):y@(y_off,_,_):xs) = do
- rest <- markBackwardTargets (y:xs)
- targets <- get
- let isTarget = y_off `elem` targets
- x_new = case x_bbend of
- Just _ -> x -- already marked, don't change
- Nothing -> if isTarget then checkX y_off else x
- checkX w16 = case x_bbend of
- Nothing -> (x_off, Just $ FallThrough w16, x_ins) -- mark previous insn
- _ -> error "basicblock: something is wrong"
- return $ x_new:rest
-
+ xs' = evalState (calculateInstructionOffset xs) []
buildCFG' :: MapBB -> [OffIns] -> [OffIns] -> MapBB
parseBasicBlock :: Int -> [OffIns] -> BasicBlock
-parseBasicBlock i insns = BasicBlock insonly endblock
+parseBasicBlock i insns = emptyBasicBlock { code = insonly, successor = endblock }
where
(lastblock, is) = takeWhilePlusOne validins omitins insns
(_, _, insonly) = unzip3 is
takeWhilePlusOne _ _ [] = (Nothing, [])
takeWhilePlusOne p omit (x:xs)
| omit x = next
- | p x = (\(ys, xs') -> (ys, x:xs')) next
+ | p x = second (x:) next
| otherwise = (Just x, [x])
where
next = takeWhilePlusOne p omit xs
IRETURN -> notarget
ARETURN -> notarget
RETURN -> notarget
- _ -> ((off, Nothing, x):) <$> next
+ _ -> normalins
where
+ normalins = do
+ tailinsns <- next -- eval remaining instructions
+ isNextInsATarget <- (elem newoffset) <$> get
+ let bbtyp = if isNextInsATarget
+ then Just $ FallThrough newoffset
+ else Nothing
+ return $ (off, bbtyp, x):tailinsns
notarget = ((off, Just Return, x):) <$> next
onetarget w16 = do
let jump = off `addW16Signed` w16
let jump = off `addW16Signed` w16
modify (jump:)
((off, Just $ TwoTarget nojump jump, x):) <$> next
- next = cio' newoffset xs
- newoffset = (off + insnLength x, Nothing, NOP)
+ next = cio' nextins xs
+ nextins = (newoffset, Nothing, NOP)
+ newoffset = off + insnLength x
-- TODO(bernhard): does GHC memomize results? i.e. does it calculate the size
-- of `NOP' only once?