1 {-# LANGUAGE OverloadedStrings #-}
2 module Mate.BasicBlocks(
10 testCFG -- added by hs to perform benches from outside
13 import Data.Binary hiding (get)
15 import qualified Data.Map as M
16 import qualified Data.Set as S
17 import qualified Data.ByteString.Lazy as B
19 import Control.Monad.State
20 import Control.Applicative
31 -- (offset in bytecode, offset to jump target, ins)
32 type OffIns = (Int, Maybe BBEnd, Instruction)
35 type BBState = S.Set Target
36 type AnalyseState = State BBState [OffIns]
39 noException :: B.ByteString
42 emptyBasicBlock :: BasicBlock
43 emptyBasicBlock = BasicBlock
45 , exception = noException
46 , successor = Return }
48 printMapBB :: MapBB -> IO ()
51 let keys = M.keys hmap
52 mapM_ (printfBb . flip (++) ", " . show) keys
53 printfBb "\n\nBasicBlocks:\n"
56 printMapBB' :: [BlockID] -> MapBB -> IO ()
57 printMapBB' [] _ = return ()
58 printMapBB' (i:is) hmap' = case M.lookup i hmap' of
60 printfBb $ "Block " ++ show i ++ "\n"
61 mapM_ (printfBb . flip (++) "\n" . (++) "\t" . show) $ code bb
62 printfBb $ case successor bb of
64 FallThrough t1 -> "Sucessor: " ++ show t1 ++ "\n"
65 OneTarget t1 -> "Sucessor: " ++ show t1 ++ "\n"
66 TwoTarget t1 t2 -> "Sucessor: " ++ show t1 ++ ", " ++ show t2 ++ "\n"
68 Nothing -> error $ "BlockID " ++ show i ++ " not found."
71 testInstance :: String -> B.ByteString -> MethodSignature -> IO ()
72 testInstance cf method sig = do
73 cls <- parseClassFile cf
74 hmap <- parseMethod cls method sig
84 test_01, test_02, test_03, test_04 :: IO ()
85 test_01 = testInstance "./tests/Fib.class" "fib"
86 test_02 = testInstance "./tests/While.class" "f"
87 test_03 = testInstance "./tests/While.class" "g"
88 test_04 = testInstance "./tests/Fac.class" "fac"
92 parseMethod :: Class Direct -> B.ByteString -> MethodSignature -> IO RawMethod
93 parseMethod cls methodname sig = do
94 let method = fromMaybe
95 (error $ "method " ++ (show . toString) methodname ++ " not found")
96 (lookupMethodSig methodname sig cls)
97 let codeseg = fromMaybe
98 (error $ "codeseg " ++ (show . toString) methodname ++ " not found")
99 (attrByName method "Code")
100 let decoded = decodeMethod codeseg
101 let mapbb = testCFG decoded
102 let locals = fromIntegral (codeMaxLocals decoded)
103 let stacks = fromIntegral (codeStackSize decoded)
104 let codelen = fromIntegral (codeLength decoded)
105 let methoddirect = methodInfoToMethod (MethodInfo methodname "" sig) cls
106 let isStatic = methodIsStatic methoddirect
107 let nametype = methodNameType methoddirect
108 let argscount = methodGetArgsCount nametype + (if isStatic then 0 else 1)
111 -- small example how to get information about
112 -- exceptions of a method
113 let (Just m) = lookupMethodSig methodname sig cls
114 case attrByName m "Code" of
116 printfBb $ printf "exception: no handler for this method\n"
117 Just exceptionstream ->
118 printfBb $ printf "exception: \"%s\"\n" (show $ codeExceptions $ decodeMethod exceptionstream)
120 let msig = methodSignature method
121 printfBb $ printf "BB: analysing \"%s\"\n" $ toString (methodname `B.append` ": " `B.append` encode msig)
123 return $ RawMethod mapbb locals stacks argscount codelen
126 testCFG :: Code -> MapBB
127 testCFG c = buildCFG (codeInstructions c) (codeExceptions c)
129 buildCFG :: [Instruction] -> [CodeException] -> MapBB
130 buildCFG xs excps = execState (mapM (buildCFG' offins) $ alltargets ++ handlerEntries) M.empty
132 (offins, targets) = runState (calculateInstructionOffset tryBlocks xs) S.empty
133 alltargets = S.toList $ S.insert 0 targets
134 tryBlocks = map (fromIntegral . eStartPC) excps
135 handlerEntries = map (fromIntegral . eHandlerPC) excps
137 buildCFG' :: [OffIns] -> Int -> State MapBB ()
138 buildCFG' insns off = do
139 let value = parseBasicBlock off insns
140 modify (M.insert off value)
142 parseBasicBlock :: Int -> [OffIns] -> BasicBlock
143 parseBasicBlock i insns = emptyBasicBlock { code = insonly, successor = endblock }
145 (lastblock, is) = takeWhilePlusOne validins omitins insns
146 (_, _, insonly) = unzip3 is
147 (_, Just endblock, _) = fromJust lastblock
149 -- also take last (non-matched) element and return it
150 takeWhilePlusOne :: (a -> Bool) -> (a -> Bool) -> [a] -> (Maybe a, [a])
151 takeWhilePlusOne _ _ [] = (Nothing, [])
152 takeWhilePlusOne p omit (x:xs)
154 | p x = second (x:) next
155 | otherwise = (Just x, [x])
157 next = takeWhilePlusOne p omit xs
159 validins :: OffIns -> Bool
160 validins (_, x, _) = isNothing x
162 omitins :: OffIns -> Bool
163 omitins (off, _, _) = off < i
166 calculateInstructionOffset :: [BlockID] -> [Instruction] -> AnalyseState
167 calculateInstructionOffset exstarts = cio' 0
169 addW16Signed i w16 = i + fromIntegral s16
170 where s16 = fromIntegral w16 :: Int16
172 cio' :: Int -> [Instruction] -> AnalyseState
173 cio' _ [] = return $ []
174 cio' off (x:xs) = case x of
175 IF _ w16 -> twotargets w16
176 IF_ICMP _ w16 -> twotargets w16
177 IF_ACMP _ w16 -> twotargets w16
178 IFNONNULL w16 -> twotargets w16
179 IFNULL w16 -> twotargets w16
180 GOTO w16 -> onetarget w16
185 _ -> if newoffset `elem` exstarts
187 modify (S.insert newoffset)
188 ((off, Just $ OneTarget newoffset, x):) <$> next
192 tailinsns <- next -- eval remaining instructions
193 isNextInsATarget <- (S.member newoffset) <$> get
194 let bbtyp = if isNextInsATarget
195 then Just $ FallThrough newoffset
197 return $ (off, bbtyp, x):tailinsns
198 notarget = ((off, Just Return, x):) <$> next
200 let jump = off `addW16Signed` w16
201 modify (S.insert jump)
202 ((off, Just $ OneTarget jump, x):) <$> next
205 modify (S.insert nojump)
206 let jump = off `addW16Signed` w16
207 modify (S.insert jump)
208 ((off, Just $ TwoTarget nojump jump, x):) <$> next
209 next = cio' newoffset xs
210 newoffset = off + insLen
211 insLen = insnLength x
213 -- TODO(bernhard): does GHC memomize results? i.e. does it calculate the size
214 -- of `NOP' only once?
215 insnLength :: Num a => Instruction -> a
216 insnLength = fromIntegral . B.length . encodeInstructions . (:[])