From: Bernhard Urban <lewurm@gmail.com>
Date: Mon, 2 Apr 2012 23:32:26 +0000 (+0200)
Subject: basicblock: build BBs from instructionstream
X-Git-Url: http://wien.tomnetworks.com/gitweb/?p=mate.git;a=commitdiff_plain;h=f339dd7125784b27a4bbf3eff1b38780a59c04fe

basicblock: build BBs from instructionstream
---

diff --git a/Mate/BasicBlocks.hs b/Mate/BasicBlocks.hs
index a15c5e9..f92059f 100644
--- a/Mate/BasicBlocks.hs
+++ b/Mate/BasicBlocks.hs
@@ -3,6 +3,7 @@ module Mate.BasicBlocks where
 
 import Data.Binary
 import Data.Int
+import qualified Data.Map as H
 import System.Environment
 import qualified Data.Map as M
 import qualified Data.ByteString.Lazy as B
@@ -13,21 +14,30 @@ import JVM.Converter
 import JVM.Dump
 import JVM.Assembler
 
+import Debug.Trace
+
 import Mate.Utilities
 
 type Name       = String -- use "virtual register id" instead?
 data Type       = JInt | JFloat -- add more
 type Variable   = (Type,Name)
 
+type BlockID = Int
 -- Represents a CFG node
 data BasicBlock = BasicBlock {
-                     inputs  :: [Variable],
-                     outputs :: [Variable],
-                     code    :: [Instruction] }
+                     -- 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
 
--- Represents a Control-Flow-Graph as
--- Adjacency list (add matrix representation if appropriate)
-type CFList     = [(BasicBlock, [BasicBlock])]
+type MapBB = H.Map BlockID BasicBlock
+
+-- for immediate representation for determine BBs
+type Offset = (Int, Maybe BBEnd) -- (offset in bytecode, offset to jump target)
+type OffIns = (Offset, Instruction)
 
 
 main = do
@@ -44,14 +54,32 @@ parseFile clspath method = do
                      cls <- parseClassFile clspath
                      --dumpClass cls    
                      let mainmethod = lookupMethod method cls -- "main|([Ljava/lang/String;)V" cf
-                     mapM_ putStrLn (testCFG mainmethod)
+                     let hmap = testCFG mainmethod
+                     putStr "BlockIDs: "
+                     let keys = fst $ unzip $ H.toList hmap
+                     mapM_ (putStr . (flip (++)) ", " . show) keys
+                     putStrLn "\n\nBasicBlocks:"
+                     printMapBB keys hmap
+
+printMapBB :: [BlockID] -> MapBB -> IO ()
+printMapBB [] _ = return ()
+printMapBB (i:is) hmap = case H.lookup i hmap of
+                Just bb -> do
+                           putStrLn $ "Block " ++ (show i)
+                           mapM_ putStrLn (map ((++) "\t" . show) $ code bb)
+                           case successor bb of
+                             Return -> putStrLn ""
+                             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."
 
 test_01 = parseFile "./tests/Fib.class" "fib"
 test_02 = parseFile "./tests/While.class" "f"
 test_03 = parseFile "./tests/While.class" "g"
 
 
-testCFG :: Maybe (Method Resolved) -> [String]
+testCFG :: Maybe (Method Resolved) -> MapBB
 testCFG (Just m) = case attrByName m "Code" of
                      Nothing       -> error "no code"
                      Just bytecode -> let code = decodeMethod bytecode
@@ -60,23 +88,72 @@ testCFG (Just m) = case attrByName m "Code" of
 testCFG _        = error "no method to build cfg"
 
 
-buildCFG :: [Instruction] -> [String]
-buildCFG xs = map (\(x,y) -> show x ++ ", " ++ show y) xs'
+buildCFG :: [Instruction] -> MapBB
+buildCFG xs = buildCFG' H.empty xs' xs'
   where
+  xs' :: [OffIns]
   xs' = calculateInstructionOffset xs
 
-type Offset = (Int, Maybe Int16) -- (offset in bytecode, offset to jump target)
+buildCFG' :: MapBB -> [OffIns] -> [OffIns] -> MapBB
+buildCFG' hmap [] _ = hmap
+buildCFG' hmap (((off, Just entry), _):xs) insns = buildCFG' (insertlist entryi hmap) xs insns
+  where
+  insertlist :: [BlockID] -> MapBB -> MapBB
+  insertlist [] hmap = hmap
+  insertlist (x:xs) hmap = insertlist xs newhmap
+    where
+    newhmap = if H.member x hmap then hmap else H.insert x value hmap
+    value = parseBasicBlock x insns
+
+  entryi :: [BlockID]
+  entryi = (if off == 0 then [0] else []) ++ -- also consider the entrypoint
+        case entry of
+        TwoTarget t1 t2 -> [t1, t2]
+        OneTarget t -> [t]
+        Return -> trace "should not happen" []
+
+buildCFG' hmap (((_, Nothing), _):xs) insns = buildCFG' hmap xs insns
+
 
-calculateInstructionOffset :: [Instruction] -> [(Offset, Instruction)]
+parseBasicBlock :: Int -> [OffIns] -> BasicBlock
+parseBasicBlock i insns = BasicBlock insonly endblock
+  where
+  startlist = dropWhile (\((x,_),_) -> x < i) insns
+  (Just ((_,(Just endblock)),_), is) = takeWhilePlusOne validins startlist
+  insonly = snd $ unzip is
+
+  -- also take last (non-matched) element and return it
+  takeWhilePlusOne :: (a -> Bool) -> [a] -> (Maybe a,[a])
+  takeWhilePlusOne _ [] = (Nothing,[])
+  takeWhilePlusOne p (x:xs)
+    | p x       =  let (lastins, list) = takeWhilePlusOne p xs in (lastins, (x:list))
+    | otherwise =  (Just x,[x])
+
+  validins :: ((Int, Maybe BBEnd), Instruction) -> Bool
+  validins ((_,x),_) = case x of Just _ -> False; Nothing -> True
+
+
+calculateInstructionOffset :: [Instruction] -> [OffIns]
 calculateInstructionOffset = cio' (0, Nothing)
   where
   newoffset :: Instruction -> Int -> Offset
   newoffset x off = (off + (fromIntegral $ B.length $ encodeInstructions [x]), Nothing)
-  cio' :: Offset -> [Instruction] -> [(Offset, Instruction)]
+
+  addW16Signed :: Int -> Word16 -> Int
+  addW16Signed i w16 = i + (fromIntegral s16)
+    where s16 = (fromIntegral w16) :: Int16
+
+  cio' :: Offset -> [Instruction] -> [OffIns]
   cio' _ [] = []
   -- TODO(bernhard): add more instruction with offset (IF_ACMP, JSR, ...)
-  -- TODO(bernhard): beautiful code please (BCP)
-  cio' (off,_) (x@(IF _ w16):xs) = ((off, Just $ fromIntegral w16), x):(cio' (newoffset x off) xs)
-  cio' (off,_) (x@(IF_ICMP _ w16):xs) = ((off, Just $ fromIntegral w16), x):(cio' (newoffset x off) xs)
-  cio' (off,_) (x@(GOTO w16):xs) = ((off, Just $ fromIntegral w16), x):(cio' (newoffset x off) xs)
-  cio' (off,_) (x:xs) = ((off, Nothing), x):(cio' (newoffset x off) xs)
+  cio' (off,_) (x:xs) = case x of
+      IF _ w16 -> twotargets w16
+      IF_ICMP _ w16 -> twotargets w16
+      GOTO w16 -> onetarget w16
+      IRETURN -> notarget
+      _ -> ((off, Nothing), x):next
+    where
+    notarget = ((off, Just Return), x):next
+    onetarget w16 = ((off, Just $ OneTarget $ (off `addW16Signed` w16)), x):next
+    twotargets w16 = ((off, Just $ TwoTarget (off `addW16Signed` w16) (off + 3)), x):next
+    next = cio' (newoffset x off) xs