+{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}
module Mate.BasicBlocks(
BlockID,
BasicBlock (..),
BBEnd (..),
MapBB,
+#ifdef DEBUG
printMapBB,
+ test_main,
+#endif
parseMethod,
- test_main
+ testCFG -- added by hs to perform benches from outside
)where
import Data.Binary
import Data.Int
+import Data.List
import qualified Data.Map as M
import qualified Data.ByteString.Lazy as B
import JVM.Assembler
import Mate.Utilities
+import Mate.Types
+#ifdef DEBUG
+import Text.Printf
+#endif
-type BlockID = Int
--- Represents a CFG node
-data BasicBlock = BasicBlock {
- -- inputs :: [Variable],
- -- outputs :: [Variable],
- code :: [Instruction],
- successor :: BBEnd }
-
--- describes (leaving) edges of a CFG node
-data BBEnd = Return | OneTarget BlockID | TwoTarget BlockID BlockID deriving Show
-
-type MapBB = M.Map BlockID BasicBlock
-
--- for immediate representation for determine BBs
+-- for immediate representation to determine BBs
type Offset = (Int, Maybe BBEnd) -- (offset in bytecode, offset to jump target)
type OffIns = (Offset, Instruction)
+#ifdef DEBUG
printMapBB :: Maybe MapBB -> IO ()
printMapBB Nothing = putStrLn "No BasicBlock"
printMapBB (Just hmap) = do
mapM_ putStrLn (map ((++) "\t" . show) $ code bb)
case successor bb of
Return -> putStrLn ""
+ FallThrough t1 -> putStrLn $ "Sucessor: " ++ (show t1) ++ "\n"
OneTarget t1 -> putStrLn $ "Sucessor: " ++ (show t1) ++ "\n"
TwoTarget t1 t2 -> putStrLn $ "Sucessor: " ++ (show t1) ++ ", " ++ (show t2) ++ "\n"
printMapBB' is hmap
Nothing -> error $ "BlockID " ++ show i ++ " not found."
+#endif
+#ifdef DEBUG
testInstance :: String -> B.ByteString -> IO ()
testInstance cf method = do
cls <- parseClassFile cf
hmap <- parseMethod cls method
printMapBB hmap
+#endif
+#ifdef DEBUG
test_main :: IO ()
test_main = do
test_01
test_02
test_03
+ test_04
-test_01, test_02, test_03 :: IO ()
+test_01, test_02, test_03, test_04 :: IO ()
test_01 = testInstance "./tests/Fib.class" "fib"
test_02 = testInstance "./tests/While.class" "f"
test_03 = testInstance "./tests/While.class" "g"
+test_04 = testInstance "./tests/Fac.class" "fac"
+#endif
parseMethod :: Class Resolved -> B.ByteString -> IO (Maybe MapBB)
parseMethod cls method = do
+ let maybe_bb = testCFG $ lookupMethod method cls
+#ifdef DEBUG
putStr "BB: analysing: "
let msig = methodSignature $ (classMethods cls) !! 1
- B.putStrLn (method `B.append` ": " `B.append` (encode msig))
- return $ testCFG $ lookupMethod method cls
+ putStrLn $ toString (method `B.append` ": " `B.append` (encode msig))
+ printMapBB maybe_bb
+#endif
+#ifdef DEBUG
+ -- small example how to get information about
+ -- exceptions of a method
+ -- TODO: remove ;-)
+ let (Just m) = lookupMethod method cls
+ case attrByName m "Code" of
+ Nothing -> printf "exception: no handler for this method\n"
+ Just exceptionstream -> printf "exception: \"%s\"\n" (show $ codeExceptions $ decodeMethod exceptionstream)
+#endif
+ return maybe_bb
testCFG :: Maybe (Method Resolved) -> Maybe MapBB
buildCFG xs = buildCFG' M.empty xs' xs'
where
xs' :: [OffIns]
- xs' = calculateInstructionOffset xs
+ xs' = markBackwardTargets $ calculateInstructionOffset xs
+
+-- get already calculated jmp-targets and mark the predecessor of the
+-- target-instruction as "FallThrough". we just care about backwards
+-- jumps here (forward jumps are handled in buildCFG')
+markBackwardTargets :: [OffIns] -> [OffIns]
+markBackwardTargets [] = []
+markBackwardTargets (x:[]) = [x]
+markBackwardTargets insns@(x@((x_off,x_bbend),x_ins):y@((y_off,_),_):xs) =
+ (x_new):(markBackwardTargets (y:xs))
+ where
+ x_new = if isTarget then checkX y_off else x
+ checkX w16 = case x_bbend of
+ Just _ -> x -- already marked, don't change
+ Nothing -> ((x_off, Just $ FallThrough w16), x_ins) -- mark previous insn
+
+ -- look through all remaining insns in the stream if there is a jmp to `y'
+ isTarget = case find cmpOffset insns of Just _ -> True; Nothing -> False
+ cmpOffset ((_,(Just (OneTarget w16))),_) = w16 == y_off
+ cmpOffset ((_,(Just (TwoTarget _ w16))),_) = w16 == y_off
+ cmpOffset _ = False
+
buildCFG' :: MapBB -> [OffIns] -> [OffIns] -> MapBB
buildCFG' hmap [] _ = hmap
case entry of
Just (TwoTarget t1 t2) -> [t1, t2]
Just (OneTarget t) -> [t]
+ Just (FallThrough t) -> [t]
Just (Return) -> []
Nothing -> []
cio' (off,_) (x:xs) = case x of
IF _ w16 -> twotargets w16
IF_ICMP _ w16 -> twotargets w16
+ IF_ACMP _ w16 -> twotargets w16
GOTO w16 -> onetarget w16
IRETURN -> notarget
+ ARETURN -> notarget
RETURN -> notarget
_ -> ((off, Nothing), x):next
where