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)
110 let msig = methodSignature method
111 printfBb $ printf "BB: analysing \"%s\"\n" $ toString (methodname `B.append` ": " `B.append` encode msig)
113 -- small example how to get information about
114 -- exceptions of a method
116 let (Just m) = lookupMethodSig methodname sig cls
117 case attrByName m "Code" of
119 printfBb $ printf "exception: no handler for this method\n"
120 Just exceptionstream ->
121 printfBb $ printf "exception: \"%s\"\n" (show $ codeExceptions $ decodeMethod exceptionstream)
122 return $ RawMethod mapbb locals stacks argscount codelen
125 testCFG :: Code -> MapBB
126 testCFG = buildCFG . codeInstructions
128 buildCFG :: [Instruction] -> MapBB
129 buildCFG xs = execState (mapM (buildCFG' offins) alltargets) M.empty
131 (offins, targets) = runState (calculateInstructionOffset xs) S.empty
132 alltargets = S.toList $ S.insert 0 targets
134 buildCFG' :: [OffIns] -> Int -> State MapBB ()
135 buildCFG' insns off = do
136 let value = parseBasicBlock off insns
137 modify (M.insert off value)
139 parseBasicBlock :: Int -> [OffIns] -> BasicBlock
140 parseBasicBlock i insns = emptyBasicBlock { code = insonly, successor = endblock }
142 (lastblock, is) = takeWhilePlusOne validins omitins insns
143 (_, _, insonly) = unzip3 is
144 (_, Just endblock, _) = fromJust lastblock
146 -- also take last (non-matched) element and return it
147 takeWhilePlusOne :: (a -> Bool) -> (a -> Bool) -> [a] -> (Maybe a, [a])
148 takeWhilePlusOne _ _ [] = (Nothing, [])
149 takeWhilePlusOne p omit (x:xs)
151 | p x = second (x:) next
152 | otherwise = (Just x, [x])
154 next = takeWhilePlusOne p omit xs
156 validins :: OffIns -> Bool
157 validins (_, x, _) = isNothing x
159 omitins :: OffIns -> Bool
160 omitins (off, _, _) = off < i
163 calculateInstructionOffset :: [Instruction] -> AnalyseState
164 calculateInstructionOffset = cio' (0, Nothing, NOP)
166 addW16Signed :: Int -> Word16 -> Int
167 addW16Signed i w16 = i + fromIntegral s16
168 where s16 = fromIntegral w16 :: Int16
170 cio' :: OffIns -> [Instruction] -> AnalyseState
171 cio' _ [] = return $ []
172 cio' (off,_,_) (x:xs) = case x of
173 IF _ w16 -> twotargets w16
174 IF_ICMP _ w16 -> twotargets w16
175 IF_ACMP _ w16 -> twotargets w16
176 IFNONNULL w16 -> twotargets w16
177 IFNULL w16 -> twotargets w16
178 GOTO w16 -> onetarget w16
185 tailinsns <- next -- eval remaining instructions
186 isNextInsATarget <- (S.member newoffset) <$> get
187 let bbtyp = if isNextInsATarget
188 then Just $ FallThrough newoffset
190 return $ (off, bbtyp, x):tailinsns
191 notarget = ((off, Just Return, x):) <$> next
193 let jump = off `addW16Signed` w16
194 modify (S.insert jump)
195 ((off, Just $ OneTarget jump, x):) <$> next
198 modify (S.insert nojump)
199 let jump = off `addW16Signed` w16
200 modify (S.insert jump)
201 ((off, Just $ TwoTarget nojump jump, x):) <$> next
202 next = cio' nextins xs
203 nextins = (newoffset, Nothing, NOP)
204 newoffset = off + insnLength x
206 -- TODO(bernhard): does GHC memomize results? i.e. does it calculate the size
207 -- of `NOP' only once?
208 insnLength :: Num a => Instruction -> a
209 insnLength = fromIntegral . B.length . encodeInstructions . (:[])