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
35 -- for immediate representation to determine BBs
36 type Offset = (Int, Maybe BBEnd) -- (offset in bytecode, offset to jump target)
37 type OffIns = (Offset, Instruction)
41 printMapBB :: Maybe MapBB -> IO ()
42 printMapBB Nothing = putStrLn "No BasicBlock"
43 printMapBB (Just hmap) = do
45 let keys = fst $ unzip $ M.toList hmap
46 mapM_ (putStr . (flip (++)) ", " . show) keys
47 putStrLn "\n\nBasicBlocks:"
50 printMapBB' :: [BlockID] -> MapBB -> IO ()
51 printMapBB' [] _ = return ()
52 printMapBB' (i:is) hmap' = case M.lookup i hmap' of
54 putStrLn $ "Block " ++ (show i)
55 mapM_ putStrLn (map ((++) "\t" . show) $ code bb)
58 FallThrough t1 -> putStrLn $ "Sucessor: " ++ (show t1) ++ "\n"
59 OneTarget t1 -> putStrLn $ "Sucessor: " ++ (show t1) ++ "\n"
60 TwoTarget t1 t2 -> putStrLn $ "Sucessor: " ++ (show t1) ++ ", " ++ (show t2) ++ "\n"
62 Nothing -> error $ "BlockID " ++ show i ++ " not found."
66 testInstance :: String -> B.ByteString -> IO ()
67 testInstance cf method = do
68 cls <- parseClassFile cf
69 hmap <- parseMethod cls method
81 test_01, test_02, test_03, test_04 :: IO ()
82 test_01 = testInstance "./tests/Fib.class" "fib"
83 test_02 = testInstance "./tests/While.class" "f"
84 test_03 = testInstance "./tests/While.class" "g"
85 test_04 = testInstance "./tests/Fac.class" "fac"
89 parseMethod :: Class Resolved -> B.ByteString -> IO (Maybe MapBB)
90 parseMethod cls method = do
91 let maybe_bb = testCFG $ lookupMethod method cls
92 let msig = methodSignature $ (classMethods cls) !! 1
93 printf_bb "BB: analysing \"%s\"\n" $ toString (method `B.append` ": " `B.append` (encode msig))
97 -- small example how to get information about
98 -- exceptions of a method
100 let (Just m) = lookupMethod method cls
101 case attrByName m "Code" of
102 Nothing -> printf_bb "exception: no handler for this method\n"
103 Just exceptionstream -> printf_bb "exception: \"%s\"\n" (show $ codeExceptions $ decodeMethod exceptionstream)
107 testCFG :: Maybe (Method Resolved) -> Maybe MapBB
108 testCFG (Just m) = case attrByName m "Code" of
110 Just bytecode -> Just $ buildCFG $ codeInstructions $ decodeMethod bytecode
114 buildCFG :: [Instruction] -> MapBB
115 buildCFG xs = buildCFG' M.empty xs' xs'
118 xs' = markBackwardTargets $ calculateInstructionOffset xs
120 -- get already calculated jmp-targets and mark the predecessor of the
121 -- target-instruction as "FallThrough". we just care about backwards
122 -- jumps here (forward jumps are handled in buildCFG')
123 markBackwardTargets :: [OffIns] -> [OffIns]
124 markBackwardTargets [] = []
125 markBackwardTargets (x:[]) = [x]
126 markBackwardTargets insns@(x@((x_off,x_bbend),x_ins):y@((y_off,_),_):xs) =
127 (x_new):(markBackwardTargets (y:xs))
129 x_new = if isTarget then checkX y_off else x
130 checkX w16 = case x_bbend of
131 Just _ -> x -- already marked, don't change
132 Nothing -> ((x_off, Just $ FallThrough w16), x_ins) -- mark previous insn
134 -- look through all remaining insns in the stream if there is a jmp to `y'
135 isTarget = case find cmpOffset insns of Just _ -> True; Nothing -> False
136 cmpOffset ((_,(Just (OneTarget w16))),_) = w16 == y_off
137 cmpOffset ((_,(Just (TwoTarget _ w16))),_) = w16 == y_off
141 buildCFG' :: MapBB -> [OffIns] -> [OffIns] -> MapBB
142 buildCFG' hmap [] _ = hmap
143 buildCFG' hmap (((off, entry), _):xs) insns = buildCFG' (insertlist entryi hmap) xs insns
145 insertlist :: [BlockID] -> MapBB -> MapBB
146 insertlist [] hmap' = hmap'
147 insertlist (y:ys) hmap' = insertlist ys newhmap
149 newhmap = if M.member y hmap' then hmap' else M.insert y value hmap'
150 value = parseBasicBlock y insns
153 entryi = (if off == 0 then [0] else []) ++ -- also consider the entrypoint
155 Just (TwoTarget t1 t2) -> [t1, t2]
156 Just (OneTarget t) -> [t]
157 Just (FallThrough t) -> [t]
162 parseBasicBlock :: Int -> [OffIns] -> BasicBlock
163 parseBasicBlock i insns = BasicBlock insonly endblock
165 startlist = dropWhile (\((x,_),_) -> x < i) insns
166 (Just ((_,(Just endblock)),_), is) = takeWhilePlusOne validins startlist
167 insonly = snd $ unzip is
169 -- also take last (non-matched) element and return it
170 takeWhilePlusOne :: (a -> Bool) -> [a] -> (Maybe a,[a])
171 takeWhilePlusOne _ [] = (Nothing,[])
172 takeWhilePlusOne p (x:xs)
173 | p x = let (lastins, list) = takeWhilePlusOne p xs in (lastins, (x:list))
174 | otherwise = (Just x,[x])
176 validins :: ((Int, Maybe BBEnd), Instruction) -> Bool
177 validins ((_,x),_) = case x of Just _ -> False; Nothing -> True
180 calculateInstructionOffset :: [Instruction] -> [OffIns]
181 calculateInstructionOffset = cio' (0, Nothing)
183 newoffset :: Instruction -> Int -> Offset
184 newoffset x off = (off + (fromIntegral $ B.length $ encodeInstructions [x]), Nothing)
186 addW16Signed :: Int -> Word16 -> Int
187 addW16Signed i w16 = i + (fromIntegral s16)
188 where s16 = (fromIntegral w16) :: Int16
190 cio' :: Offset -> [Instruction] -> [OffIns]
192 -- TODO(bernhard): add more instruction with offset (IF_ACMP, JSR, ...)
193 cio' (off,_) (x:xs) = case x of
194 IF _ w16 -> twotargets w16
195 IF_ICMP _ w16 -> twotargets w16
196 IF_ACMP _ w16 -> twotargets w16
197 GOTO w16 -> onetarget w16
201 _ -> ((off, Nothing), x):next
203 notarget = ((off, Just Return), x):next
204 onetarget w16 = ((off, Just $ OneTarget $ (off `addW16Signed` w16)), x):next
205 twotargets w16 = ((off, Just $ TwoTarget (off + 3) (off `addW16Signed` w16)), x):next
206 next = cio' (newoffset x off) xs