import Data.Binary hiding (get)
import Data.Int
import qualified Data.Map as M
+import qualified Data.Set as S
import qualified Data.ByteString.Lazy as B
import Data.Maybe
import Control.Monad.State
-- (offset in bytecode, offset to jump target, ins)
type OffIns = (Int, Maybe BBEnd, Instruction)
-type Targets = [BlockID]
-type BBState = Targets
+type Target = BlockID
+type BBState = S.Set Target
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: "
let nametype = methodNameType methoddirect
let argscount = methodGetArgsCount nametype + (if isStatic then 0 else 1)
- let msig = methodSignature method
- printfBb $ printf "BB: analysing \"%s\"\n" $ toString (methodname `B.append` ": " `B.append` encode msig)
- printMapBB mapbb
+ -- TODO: remove ;-)
-- small example how to get information about
-- exceptions of a method
- -- TODO: remove ;-)
let (Just m) = lookupMethodSig methodname sig cls
case attrByName m "Code" of
Nothing ->
printfBb $ printf "exception: no handler for this method\n"
Just exceptionstream ->
printfBb $ printf "exception: \"%s\"\n" (show $ codeExceptions $ decodeMethod exceptionstream)
+ -- [/remove]
+ let msig = methodSignature method
+ printfBb $ printf "BB: analysing \"%s\"\n" $ toString (methodname `B.append` ": " `B.append` encode msig)
+ printMapBB mapbb
return $ RawMethod mapbb locals stacks argscount codelen
testCFG :: Code -> MapBB
-testCFG = buildCFG . codeInstructions
+testCFG c = buildCFG (codeInstructions c) (codeExceptions c)
-buildCFG :: [Instruction] -> MapBB
-buildCFG xs = buildCFG' M.empty xs' xs'
+buildCFG :: [Instruction] -> [CodeException] -> MapBB
+buildCFG xs excps = execState (mapM (buildCFG' offins) $ alltargets ++ handlerEntries) M.empty
where
- xs' :: [OffIns]
- xs' = evalState (calculateInstructionOffset xs) []
-
-
-buildCFG' :: MapBB -> [OffIns] -> [OffIns] -> MapBB
-buildCFG' hmap [] _ = hmap
-buildCFG' hmap ((off, entry, _):xs) insns = buildCFG' (insertlist entryi hmap) xs insns
- where
- insertlist :: [BlockID] -> MapBB -> MapBB
- insertlist [] hmap' = hmap'
- insertlist (y:ys) hmap' = insertlist ys newhmap
- where
- newhmap = if M.member y hmap' then hmap' else M.insert y value hmap'
- value = parseBasicBlock y insns
- entryi :: [BlockID]
- entryi = if off == 0 then 0:ys else ys -- also consider the entrypoint
- where
- ys = case entry of
- Just (TwoTarget t1 t2) -> [t1, t2]
- Just (OneTarget t) -> [t]
- Just (FallThrough t) -> [t]
- Just Return -> []
- Nothing -> []
+ (offins, targets) = runState (calculateInstructionOffset tryBlocks xs) S.empty
+ alltargets = S.toList $ S.insert 0 targets
+ tryBlocks = map (fromIntegral . eStartPC) excps
+ handlerEntries = map (fromIntegral . eHandlerPC) excps
+buildCFG' :: [OffIns] -> Int -> State MapBB ()
+buildCFG' insns off = do
+ let value = parseBasicBlock off insns
+ modify (M.insert off value)
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
omitins (off, _, _) = off < i
-calculateInstructionOffset :: [Instruction] -> AnalyseState
-calculateInstructionOffset = cio' (0, Nothing, NOP)
+calculateInstructionOffset :: [BlockID] -> [Instruction] -> AnalyseState
+calculateInstructionOffset exstarts = cio' 0
where
- addW16Signed :: Int -> Word16 -> Int
addW16Signed i w16 = i + fromIntegral s16
where s16 = fromIntegral w16 :: Int16
- cio' :: OffIns -> [Instruction] -> AnalyseState
+ cio' :: Int -> [Instruction] -> AnalyseState
cio' _ [] = return $ []
- cio' (off,_,_) (x:xs) = case x of
+ cio' off (x:xs) = case x of
IF _ w16 -> twotargets w16
IF_ICMP _ w16 -> twotargets w16
IF_ACMP _ w16 -> twotargets w16
IFNONNULL w16 -> twotargets w16
IFNULL w16 -> twotargets w16
GOTO w16 -> onetarget w16
+ ATHROW -> notarget
IRETURN -> notarget
ARETURN -> notarget
RETURN -> notarget
- _ -> normalins
+ _ -> if newoffset `elem` exstarts
+ then do
+ modify (S.insert newoffset)
+ ((off, Just $ OneTarget newoffset, x):) <$> next
+ else normalins
where
normalins = do
tailinsns <- next -- eval remaining instructions
- isNextInsATarget <- (elem newoffset) <$> get
+ isNextInsATarget <- (S.member newoffset) <$> get
let bbtyp = if isNextInsATarget
then Just $ FallThrough newoffset
else Nothing
notarget = ((off, Just Return, x):) <$> next
onetarget w16 = do
let jump = off `addW16Signed` w16
- modify (jump:)
+ modify (S.insert jump)
((off, Just $ OneTarget jump, x):) <$> next
twotargets w16 = do
let nojump = off + 3
- modify (nojump:)
+ modify (S.insert nojump)
let jump = off `addW16Signed` w16
- modify (jump:)
+ modify (S.insert jump)
((off, Just $ TwoTarget nojump jump, x):) <$> next
- next = cio' nextins xs
- nextins = (newoffset, Nothing, NOP)
- newoffset = off + insnLength x
+ next = cio' newoffset xs
+ newoffset = off + insLen
+ insLen = insnLength x
-- TODO(bernhard): does GHC memomize results? i.e. does it calculate the size
-- of `NOP' only once?