2 {-# LANGUAGE OverloadedStrings #-}
4 module Mate.BasicBlocks(
14 testCFG -- added by hs to perform benches from outside
20 import qualified Data.Map as M
21 import qualified Data.ByteString.Lazy as B
34 -- for immediate representation to determine BBs
35 type Offset = (Int, Maybe BBEnd) -- (offset in bytecode, offset to jump target)
36 type OffIns = (Offset, Instruction)
40 printMapBB :: Maybe MapBB -> IO ()
41 printMapBB Nothing = putStrLn "No BasicBlock"
42 printMapBB (Just hmap) = do
44 let keys = fst $ unzip $ M.toList hmap
45 mapM_ (putStr . (flip (++)) ", " . show) keys
46 putStrLn "\n\nBasicBlocks:"
49 printMapBB' :: [BlockID] -> MapBB -> IO ()
50 printMapBB' [] _ = return ()
51 printMapBB' (i:is) hmap' = case M.lookup i hmap' of
53 putStrLn $ "Block " ++ (show i)
54 mapM_ putStrLn (map ((++) "\t" . show) $ code bb)
57 FallThrough t1 -> putStrLn $ "Sucessor: " ++ (show t1) ++ "\n"
58 OneTarget t1 -> putStrLn $ "Sucessor: " ++ (show t1) ++ "\n"
59 TwoTarget t1 t2 -> putStrLn $ "Sucessor: " ++ (show t1) ++ ", " ++ (show t2) ++ "\n"
61 Nothing -> error $ "BlockID " ++ show i ++ " not found."
65 testInstance :: String -> B.ByteString -> IO ()
66 testInstance cf method = do
67 cls <- parseClassFile cf
68 hmap <- parseMethod cls method
80 test_01, test_02, test_03, test_04 :: IO ()
81 test_01 = testInstance "./tests/Fib.class" "fib"
82 test_02 = testInstance "./tests/While.class" "f"
83 test_03 = testInstance "./tests/While.class" "g"
84 test_04 = testInstance "./tests/Fac.class" "fac"
88 parseMethod :: Class Direct -> B.ByteString -> IO (Maybe MapBB)
89 parseMethod cls method = do
90 let maybe_bb = testCFG $ lookupMethod method cls
91 let msig = methodSignature $ classMethods cls !! 1
92 printfBb "BB: analysing \"%s\"\n" $ toString (method `B.append` ": " `B.append` encode msig)
96 -- small example how to get information about
97 -- exceptions of a method
99 let (Just m) = lookupMethod method cls
100 case attrByName m "Code" of
101 Nothing -> printfBb "exception: no handler for this method\n"
102 Just exceptionstream -> printfBb "exception: \"%s\"\n" (show $ codeExceptions $ decodeMethod exceptionstream)
106 testCFG :: Maybe (Method Direct) -> Maybe MapBB
107 testCFG (Just m) = case attrByName m "Code" of
109 Just bytecode -> Just $ buildCFG $ codeInstructions $ decodeMethod bytecode
113 buildCFG :: [Instruction] -> MapBB
114 buildCFG xs = buildCFG' M.empty xs' xs'
117 xs' = markBackwardTargets $ calculateInstructionOffset xs
119 -- get already calculated jmp-targets and mark the predecessor of the
120 -- target-instruction as "FallThrough". we just care about backwards
121 -- jumps here (forward jumps are handled in buildCFG')
122 markBackwardTargets :: [OffIns] -> [OffIns]
123 markBackwardTargets [] = []
124 markBackwardTargets (x:[]) = [x]
125 markBackwardTargets insns@(x@((x_off,x_bbend),x_ins):y@((y_off,_),_):xs) =
126 x_new:markBackwardTargets (y:xs)
128 x_new = if isTarget then checkX y_off else x
129 checkX w16 = case x_bbend of
130 Just _ -> x -- already marked, don't change
131 Nothing -> ((x_off, Just $ FallThrough w16), x_ins) -- mark previous insn
133 -- look through all remaining insns in the stream if there is a jmp to `y'
134 isTarget = case find cmpOffset insns of Just _ -> True; Nothing -> False
135 cmpOffset ((_,Just (OneTarget w16)),_) = w16 == y_off
136 cmpOffset ((_,Just (TwoTarget _ w16)),_) = w16 == y_off
140 buildCFG' :: MapBB -> [OffIns] -> [OffIns] -> MapBB
141 buildCFG' hmap [] _ = hmap
142 buildCFG' hmap (((off, entry), _):xs) insns = buildCFG' (insertlist entryi hmap) xs insns
144 insertlist :: [BlockID] -> MapBB -> MapBB
145 insertlist [] hmap' = hmap'
146 insertlist (y:ys) hmap' = insertlist ys newhmap
148 newhmap = if M.member y hmap' then hmap' else M.insert y value hmap'
149 value = parseBasicBlock y insns
152 entryi = if off == 0 then 0:ys else ys -- also consider the entrypoint
153 where ys = case entry of
154 Just (TwoTarget t1 t2) -> [t1, t2]
155 Just (OneTarget t) -> [t]
156 Just (FallThrough t) -> [t]
161 parseBasicBlock :: Int -> [OffIns] -> BasicBlock
162 parseBasicBlock i insns = BasicBlock insonly endblock
164 startlist = dropWhile (\((x,_),_) -> x < i) insns
165 (Just ((_, Just endblock),_), is) = takeWhilePlusOne validins startlist
166 insonly = snd $ unzip is
168 -- also take last (non-matched) element and return it
169 takeWhilePlusOne :: (a -> Bool) -> [a] -> (Maybe a,[a])
170 takeWhilePlusOne _ [] = (Nothing,[])
171 takeWhilePlusOne p (x:xs)
172 | p x = let (lastins, list) = takeWhilePlusOne p xs in (lastins, x:list)
173 | otherwise = (Just x,[x])
175 validins :: ((Int, Maybe BBEnd), Instruction) -> Bool
176 validins ((_,x),_) = case x of Just _ -> False; Nothing -> True
179 calculateInstructionOffset :: [Instruction] -> [OffIns]
180 calculateInstructionOffset = cio' (0, Nothing)
182 newoffset :: Instruction -> Int -> Offset
183 newoffset x off = (off + fromIntegral (B.length $ encodeInstructions [x]), Nothing)
185 addW16Signed :: Int -> Word16 -> Int
186 addW16Signed i w16 = i + fromIntegral s16
187 where s16 = fromIntegral w16 :: Int16
189 cio' :: Offset -> [Instruction] -> [OffIns]
191 -- TODO(bernhard): add more instruction with offset (IF_ACMP, JSR, ...)
192 cio' (off,_) (x:xs) = case x of
193 IF _ w16 -> twotargets w16
194 IF_ICMP _ w16 -> twotargets w16
195 IF_ACMP _ w16 -> twotargets w16
196 GOTO w16 -> onetarget w16
200 _ -> ((off, Nothing), x):next
202 notarget = ((off, Just Return), x):next
203 onetarget w16 = ((off, Just $ OneTarget (off `addW16Signed` w16)), x):next
204 twotargets w16 = ((off, Just $ TwoTarget (off + 3) (off `addW16Signed` w16)), x):next
205 next = cio' (newoffset x off) xs