1 {-# LANGUAGE OverloadedStrings #-}
2 module Mate.BasicBlocks(
10 testCFG -- added by hs to perform benches from outside
16 import qualified Data.Map as M
17 import qualified Data.ByteString.Lazy as B
28 -- for immediate representation to determine BBs
29 type Offset = (Int, Maybe BBEnd) -- (offset in bytecode, offset to jump target)
30 type OffIns = (Offset, Instruction)
33 printMapBB :: MapBB -> IO ()
36 let keys = M.keys hmap
37 mapM_ (printfBb . flip (++) ", " . show) keys
38 printfBb "\n\nBasicBlocks:\n"
41 printMapBB' :: [BlockID] -> MapBB -> IO ()
42 printMapBB' [] _ = return ()
43 printMapBB' (i:is) hmap' = case M.lookup i hmap' of
45 printfBb $ "Block " ++ show i ++ "\n"
46 mapM_ (printfBb . flip (++) "\n" . (++) "\t" . show) $ code bb
47 printfBb $ case successor bb of
49 FallThrough t1 -> "Sucessor: " ++ show t1 ++ "\n"
50 OneTarget t1 -> "Sucessor: " ++ show t1 ++ "\n"
51 TwoTarget t1 t2 -> "Sucessor: " ++ show t1 ++ ", " ++ show t2 ++ "\n"
53 Nothing -> error $ "BlockID " ++ show i ++ " not found."
56 testInstance :: String -> B.ByteString -> MethodSignature -> IO ()
57 testInstance cf method sig = do
58 cls <- parseClassFile cf
59 hmap <- parseMethod cls method sig
69 test_01, test_02, test_03, test_04 :: IO ()
70 test_01 = testInstance "./tests/Fib.class" "fib"
71 test_02 = testInstance "./tests/While.class" "f"
72 test_03 = testInstance "./tests/While.class" "g"
73 test_04 = testInstance "./tests/Fac.class" "fac"
77 parseMethod :: Class Direct -> B.ByteString -> MethodSignature -> IO RawMethod
78 parseMethod cls methodname sig = do
79 let method = fromMaybe
80 (error $ "method " ++ (show . toString) methodname ++ " not found")
81 (lookupMethodSig methodname sig cls)
82 let codeseg = fromMaybe
83 (error $ "codeseg " ++ (show . toString) methodname ++ " not found")
84 (attrByName method "Code")
85 let decoded = decodeMethod codeseg
86 let mapbb = testCFG decoded
87 let locals = fromIntegral (codeMaxLocals decoded)
88 let stacks = fromIntegral (codeStackSize decoded)
89 let codelen = fromIntegral (codeLength decoded)
90 let methoddirect = methodInfoToMethod (MethodInfo methodname "" sig) cls
91 let isStatic = methodIsStatic methoddirect
92 let nametype = methodNameType methoddirect
93 let argscount = methodGetArgsCount nametype + (if isStatic then 0 else 1)
95 let msig = methodSignature method
96 printfBb $ printf "BB: analysing \"%s\"\n" $ toString (methodname `B.append` ": " `B.append` encode msig)
98 -- small example how to get information about
99 -- exceptions of a method
101 let (Just m) = lookupMethodSig methodname sig cls
102 case attrByName m "Code" of
104 printfBb $ printf "exception: no handler for this method\n"
105 Just exceptionstream ->
106 printfBb $ printf "exception: \"%s\"\n" (show $ codeExceptions $ decodeMethod exceptionstream)
107 return $ RawMethod mapbb locals stacks argscount codelen
110 testCFG :: Code -> MapBB
111 testCFG = buildCFG . codeInstructions
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 = case x_bbend of
129 Just _ -> x -- already marked, don't change
130 Nothing -> if isTarget then checkX y_off else x
131 checkX w16 = case x_bbend of
132 Nothing -> ((x_off, Just $ FallThrough w16), x_ins) -- mark previous insn
133 _ -> error "basicblock: something is wrong"
135 -- look through all remaining insns in the stream if there is a jmp to `y'
136 isTarget = case find cmpOffset insns of Just _ -> True; Nothing -> False
137 cmpOffset ((_,Just (OneTarget w16)),_) = w16 == y_off
138 cmpOffset ((_,Just (TwoTarget _ w16)),_) = w16 == y_off
142 buildCFG' :: MapBB -> [OffIns] -> [OffIns] -> MapBB
143 buildCFG' hmap [] _ = hmap
144 buildCFG' hmap (((off, entry), _):xs) insns = buildCFG' (insertlist entryi hmap) xs insns
146 insertlist :: [BlockID] -> MapBB -> MapBB
147 insertlist [] hmap' = hmap'
148 insertlist (y:ys) hmap' = insertlist ys newhmap
150 newhmap = if M.member y hmap' then hmap' else M.insert y value hmap'
151 value = parseBasicBlock y insns
153 entryi = if off == 0 then 0:ys else ys -- also consider the entrypoint
156 Just (TwoTarget t1 t2) -> [t1, t2]
157 Just (OneTarget t) -> [t]
158 Just (FallThrough t) -> [t]
163 parseBasicBlock :: Int -> [OffIns] -> BasicBlock
164 parseBasicBlock i insns = BasicBlock insonly endblock
166 startlist = dropWhile (\((x,_),_) -> x < i) insns
167 (Just ((_, Just endblock),_), is) = takeWhilePlusOne validins startlist
168 insonly = snd $ unzip is
170 -- also take last (non-matched) element and return it
171 takeWhilePlusOne :: (a -> Bool) -> [a] -> (Maybe a,[a])
172 takeWhilePlusOne _ [] = (Nothing,[])
173 takeWhilePlusOne p (x:xs)
174 | p x = let (lastins, list) = takeWhilePlusOne p xs in (lastins, x:list)
175 | otherwise = (Just x,[x])
177 validins :: ((Int, Maybe BBEnd), Instruction) -> Bool
178 validins ((_,x),_) = case x of Just _ -> False; Nothing -> True
181 calculateInstructionOffset :: [Instruction] -> [OffIns]
182 calculateInstructionOffset = cio' (0, Nothing)
184 newoffset :: Instruction -> Int -> Offset
185 newoffset x off = (off + fromIntegral (B.length $ encodeInstructions [x]), Nothing)
187 addW16Signed :: Int -> Word16 -> Int
188 addW16Signed i w16 = i + fromIntegral s16
189 where s16 = fromIntegral w16 :: Int16
191 cio' :: Offset -> [Instruction] -> [OffIns]
193 -- TODO(bernhard): add more instruction with offset (IF_ACMP, JSR, ...)
194 cio' (off,_) (x:xs) = case x of
195 IF _ w16 -> twotargets w16
196 IF_ICMP _ w16 -> twotargets w16
197 IF_ACMP _ w16 -> twotargets w16
198 IFNONNULL w16 -> twotargets w16
199 IFNULL w16 -> twotargets w16
200 GOTO w16 -> onetarget w16
204 _ -> ((off, Nothing), x):next
206 notarget = ((off, Just Return), x):next
207 onetarget w16 = ((off, Just $ OneTarget (off `addW16Signed` w16)), x):next
208 twotargets w16 = ((off, Just $ TwoTarget (off + 3) (off `addW16Signed` w16)), x):next
209 next = cio' (newoffset x off) xs