testCFG -- added by hs to perform benches from outside
)where
-import Data.Binary
+import Data.Binary hiding (get)
import Data.Int
-import Data.List
import qualified Data.Map as M
import qualified Data.ByteString.Lazy as B
import Data.Maybe
import Control.Monad.State
+import Control.Applicative
+import Control.Arrow
import JVM.ClassFile
import JVM.Converter
buildCFG xs = buildCFG' M.empty xs' xs'
where
xs' :: [OffIns]
- xs' = markBackwardTargets $ calculateInstructionOffset xs
+ 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] -> [OffIns]
-markBackwardTargets [] = []
-markBackwardTargets (x:[]) = [x]
-markBackwardTargets insns@(x@(x_off,x_bbend,x_ins):y@(y_off,_,_):xs) =
- x_new:markBackwardTargets (y:xs)
- where
+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
- -- look through all remaining insns in the stream if there is a jmp to `y'
- isTarget = case find cmpOffset insns of Just _ -> True; Nothing -> False
- cmpOffset (_,Just (OneTarget w16),_) = w16 == y_off
- cmpOffset (_,Just (TwoTarget _ w16),_) = w16 == y_off
- cmpOffset _ = False
buildCFG' :: MapBB -> [OffIns] -> [OffIns] -> MapBB
parseBasicBlock :: Int -> [OffIns] -> BasicBlock
parseBasicBlock i insns = BasicBlock insonly endblock
where
- startlist = dropWhile (\(x,_,_) -> x < i) insns
- (Just (_, Just endblock, _), is) = takeWhilePlusOne validins startlist
+ (lastblock, is) = takeWhilePlusOne validins omitins insns
(_, _, insonly) = unzip3 is
+ (_, Just endblock, _) = fromJust lastblock
-- also take last (non-matched) element and return it
- takeWhilePlusOne :: (a -> Bool) -> [a] -> (Maybe a,[a])
- takeWhilePlusOne _ [] = (Nothing,[])
- takeWhilePlusOne p (x:xs)
- | p x = let (lastins, list) = takeWhilePlusOne p xs in (lastins, x:list)
- | otherwise = (Just x,[x])
+ takeWhilePlusOne :: (a -> Bool) -> (a -> Bool) -> [a] -> (Maybe a, [a])
+ takeWhilePlusOne _ _ [] = (Nothing, [])
+ takeWhilePlusOne p omit (x:xs)
+ | omit x = next
+ | p x = second (x:) next
+ | otherwise = (Just x, [x])
+ where
+ next = takeWhilePlusOne p omit xs
- validins :: (Int, Maybe BBEnd, Instruction) -> Bool
- validins (_,x,_) = case x of Just _ -> False; Nothing -> True
+ validins :: OffIns -> Bool
+ validins (_, x, _) = isNothing x
+ omitins :: OffIns -> Bool
+ omitins (off, _, _) = off < i
-calculateInstructionOffset :: [Instruction] -> [OffIns]
+
+calculateInstructionOffset :: [Instruction] -> AnalyseState
calculateInstructionOffset = cio' (0, Nothing, NOP)
where
- newoffset :: Instruction -> Int -> OffIns
- newoffset x off = (off + fromIntegral (B.length $ encodeInstructions [x]), Nothing, NOP)
-
addW16Signed :: Int -> Word16 -> Int
addW16Signed i w16 = i + fromIntegral s16
where s16 = fromIntegral w16 :: Int16
- cio' :: OffIns -> [Instruction] -> [OffIns]
- cio' _ [] = []
- -- TODO(bernhard): add more instruction with offset (IF_ACMP, JSR, ...)
+ cio' :: OffIns -> [Instruction] -> AnalyseState
+ cio' _ [] = return $ []
cio' (off,_,_) (x:xs) = case x of
IF _ w16 -> twotargets w16
IF_ICMP _ w16 -> twotargets w16
IRETURN -> notarget
ARETURN -> notarget
RETURN -> notarget
- _ -> (off, Nothing, x):next
+ _ -> ((off, Nothing, x):) <$> next
where
- notarget = (off, Just Return, x):next
- onetarget w16 = (off, Just $ OneTarget (off `addW16Signed` w16), x):next
- twotargets w16 = (off, Just $ TwoTarget (off + 3) (off `addW16Signed` w16), x):next
- next = cio' (newoffset x off) xs
+ notarget = ((off, Just Return, x):) <$> next
+ onetarget w16 = do
+ let jump = off `addW16Signed` w16
+ modify (jump:)
+ ((off, Just $ OneTarget jump, x):) <$> next
+ twotargets w16 = do
+ let nojump = off + 3
+ modify (nojump:)
+ let jump = off `addW16Signed` w16
+ modify (jump:)
+ ((off, Just $ TwoTarget nojump jump, x):) <$> next
+ next = cio' newoffset xs
+ newoffset = (off + insnLength x, Nothing, NOP)
+
+-- TODO(bernhard): does GHC memomize results? i.e. does it calculate the size
+-- of `NOP' only once?
+insnLength :: Num a => Instruction -> a
+insnLength = fromIntegral . B.length . encodeInstructions . (:[])