Optimize concrete runtime contract code

hevm-cli/hevm-cli.hs

@@ -37,7 +37,7 @@ import Control.Monad.State.Strict (execStateT, liftIO)
 import Data.ByteString            (ByteString)
 import Data.List                  (intercalate, isSuffixOf)
 import Data.Text                  (unpack, pack)
-import Data.Maybe                 (fromMaybe, fromJust, mapMaybe)
+import Data.Maybe                 (fromMaybe, mapMaybe)
 import Data.Version               (showVersion)
 import Data.DoubleWord            (Word256)
 import System.IO                  (stderr)
@@ -560,7 +560,7 @@ vmFromCommand cmd = do
         decipher = hexByteString "bytes" . strip0x
         mkCode bs = if create cmd
                     then EVM.InitCode bs mempty
-                    else EVM.RuntimeCode (fromJust $ Expr.toList (ConcreteBuf bs))
+                    else EVM.RuntimeCode (EVM.ConcreteRuntimeCode bs)
         address' = if create cmd
               then addr address (createAddress origin' (word nonce 0))
               else addr address 0xacab
@@ -656,7 +656,7 @@ symvmFromCommand cmd calldata' = do
     origin'  = addr origin 0
     mkCode bs = if create cmd
                    then EVM.InitCode bs mempty
-                   else EVM.RuntimeCode (fromJust . Expr.toList $ ConcreteBuf bs)
+                   else EVM.RuntimeCode (EVM.ConcreteRuntimeCode bs)
     address' = if create cmd
           then addr address (createAddress origin' (word nonce 0))
           else addr address 0xacab

src/EVM.hs

@@ -15,7 +15,7 @@ import EVM.Types hiding (IllegalOverflow, Error)
 import EVM.Solidity
 import EVM.Concrete (createAddress, create2Address)
 import EVM.Op
-import EVM.Expr (readStorage, writeStorage, readByte, readWord, writeWord, writeByte, bufLength, indexWord, litAddr, readBytes, word256At, copySlice, isLitByte)
+import EVM.Expr (readStorage, writeStorage, readByte, readWord, writeWord, writeByte, bufLength, indexWord, litAddr, readBytes, word256At, copySlice)
 import EVM.FeeSchedule (FeeSchedule (..))
 import Options.Generic as Options
 import qualified EVM.Precompiled
@@ -305,10 +305,18 @@ data SubState = SubState
   hopefully we do not have to deal with dynamic immutable before we get a real data section...
 -}
 data ContractCode
-  = InitCode ByteString (Expr Buf)     -- ^ "Constructor" code, during contract creation
-  | RuntimeCode (V.Vector (Expr Byte)) -- ^ "Instance" code, after contract creation
+  = InitCode ByteString (Expr Buf) -- ^ "Constructor" code, during contract creation
+  | RuntimeCode RuntimeCode -- ^ "Instance" code, after contract creation
   deriving (Show)
 
+-- | We have two variants here to optimize the fully concrete case.
+-- ConcreteRuntimeCode just wraps a ByteString
+-- SymbolicRuntimeCode is a fixed length vector of potentially symbolic bytes, which lets us handle symbolic pushdata (e.g. from immutable variables in solidity).
+data RuntimeCode
+  = ConcreteRuntimeCode ByteString
+  | SymbolicRuntimeCode (V.Vector (Expr Byte))
+  deriving (Show, Eq, Ord)
+
 -- runtime err when used for symbolic code
 instance Eq ContractCode where
   (InitCode a b) == (InitCode c d) = a == c && b == d
@@ -392,7 +400,7 @@ blankState :: FrameState
 blankState = FrameState
   { _contract     = 0
   , _codeContract = 0
-  , _code         = RuntimeCode mempty
+  , _code         = RuntimeCode (ConcreteRuntimeCode "")
   , _pc           = 0
   , _stack        = mempty
   , _memory       = mempty
@@ -421,7 +429,8 @@ makeLenses ''VM
 bytecode :: Getter Contract (Expr Buf)
 bytecode = contractcode . to f
   where f (InitCode _ _) = mempty
-        f (RuntimeCode ops) = Expr.fromList ops
+        f (RuntimeCode (ConcreteRuntimeCode bs)) = ConcreteBuf bs
+        f (RuntimeCode (SymbolicRuntimeCode ops)) = Expr.fromList ops
 
 instance Semigroup Cache where
   a <> b = Cache
@@ -603,7 +612,8 @@ exec1 = do
     else do
       let ?op = case (the state code) of
                   InitCode conc _ -> BS.index conc (the state pc)
-                  RuntimeCode ops ->
+                  RuntimeCode (ConcreteRuntimeCode bs) -> BS.index bs (the state pc)
+                  RuntimeCode (SymbolicRuntimeCode ops) ->
                     fromMaybe (error "could not analyze symbolic code") $
                       unlitByte $ ops V.! the state pc
 
@@ -614,13 +624,10 @@ exec1 = do
           let !n = num x - 0x60 + 1
               !xs = case the state code of
                 InitCode conc _ -> Lit $ word $ padRight n $ BS.take n (BS.drop (1 + the state pc) conc)
-                RuntimeCode ops ->
+                RuntimeCode (ConcreteRuntimeCode bs) -> Lit $ word $ BS.take n $ BS.drop (1 + the state pc) bs
+                RuntimeCode (SymbolicRuntimeCode ops) ->
                   let bytes = V.take n $ V.drop (1 + the state pc) ops
-                  in if all isLitByte bytes then -- optimize concrete path
-                       let litBytes = V.toList $ V.catMaybes $ unlitByte <$> bytes
-                           padded = BS.replicate (32 - length litBytes) 0 <> BS.pack litBytes
-                       in Lit $ word padded
-                     else readWord (Lit 0) $ Expr.fromList $ padLeft' 32 bytes
+                  in readWord (Lit 0) $ Expr.fromList $ padLeft' 32 bytes
           limitStack 1 $
             burn g_verylow $ do
               next
@@ -1075,7 +1082,9 @@ exec1 = do
           case stk of
             (x:xs) ->
               burn g_mid $ forceConcrete x "JUMP: symbolic jumpdest" $ \x' ->
-                checkJump x' xs
+                case toInt x' of
+                  Nothing -> vmError EVM.BadJumpDestination
+                  Just i -> checkJump i xs
             _ -> underrun
 
         -- op: JUMPI
@@ -1085,7 +1094,9 @@ exec1 = do
                 burn g_high $
                   let jump :: Bool -> EVM ()
                       jump False = assign (state . stack) xs >> next
-                      jump _    = checkJump x' xs
+                      jump _    = case toInt x' of
+                        Nothing -> vmError EVM.BadJumpDestination
+                        Just i -> checkJump i xs
                   in case maybeLitWord y of
                       Just y' -> jump (0 /= y')
                       -- if the jump condition is symbolic, we explore both sides
@@ -1674,7 +1685,8 @@ accountExists addr vm =
 accountEmpty :: Contract -> Bool
 accountEmpty c =
   case view contractcode c of
-    RuntimeCode b -> null b
+    RuntimeCode (ConcreteRuntimeCode "") -> True
+    RuntimeCode (SymbolicRuntimeCode b) -> null b
     _ -> False
   && (view nonce c == 0)
   && (view balance c == 0)
@@ -1703,10 +1715,17 @@ finalize = do
       creation <- use (tx . isCreate)
       createe  <- use (state . contract)
       createeExists <- (Map.member createe) <$> use (env . contracts)
-      case Expr.toList output of
-        Nothing -> vmError $ UnexpectedSymbolicArg pc' "runtime code cannot have an abstract lentgh" [output]
-        Just ops ->
-          when (creation && createeExists) $ replaceCode createe (RuntimeCode ops)
+      let onContractCode contractCode =
+            when (creation && createeExists) $ replaceCode createe contractCode
+      case output of
+        ConcreteBuf bs ->
+          onContractCode $ RuntimeCode (ConcreteRuntimeCode bs)
+        _ ->
+          case Expr.toList output of
+            Nothing ->
+              vmError $ UnexpectedSymbolicArg pc' "runtime code cannot have an abstract lentgh" [output]
+            Just ops ->
+              onContractCode $ RuntimeCode (SymbolicRuntimeCode ops)
 
   -- compute and pay the refund to the caller and the
   -- corresponding payment to the miner
@@ -1735,7 +1754,7 @@ finalize = do
   -- pay out the block reward, recreating the miner if necessary
   preuse (env . contracts . ix miner) >>= \case
     Nothing -> modifying (env . contracts)
-      (Map.insert miner (initialContract (EVM.RuntimeCode mempty)))
+      (Map.insert miner (initialContract (EVM.RuntimeCode (ConcreteRuntimeCode ""))))
     Just _  -> noop
   modifying (env . contracts)
     (Map.adjust (over balance (+ blockReward)) miner)
@@ -2119,7 +2138,8 @@ delegateCall this gasGiven xTo xContext xValue xInOffset xInSize xOutOffset xOut
 collision :: Maybe Contract -> Bool
 collision c' = case c' of
   Just c -> (view nonce c /= 0) || case view contractcode c of
-    RuntimeCode b -> not $ null b
+    RuntimeCode (ConcreteRuntimeCode "") -> False
+    RuntimeCode (SymbolicRuntimeCode b) -> not $ null b
     _ -> True
   Nothing -> False
 
@@ -2368,17 +2388,23 @@ finishFrame how = do
           case how of
             -- Case 4: Returning during a creation?
             FrameReturned output -> do
-                case Expr.toList output of
-                  Nothing -> vmError $
-                    UnexpectedSymbolicArg
-                      (view (state . pc) oldVm)
-                      "runtime code cannot have an abstract length"
-                      [output]
-                  Just newCode -> do
-                    replaceCode createe (RuntimeCode newCode)
+              let onContractCode contractCode = do
+                    replaceCode createe contractCode
                     assign (state . returndata) mempty
                     reclaimRemainingGasAllowance
                     push (num createe)
+              case output of
+                ConcreteBuf bs ->
+                  onContractCode $ RuntimeCode (ConcreteRuntimeCode bs)
+                _ ->
+                  case Expr.toList output of
+                    Nothing -> vmError $
+                      UnexpectedSymbolicArg
+                        (view (state . pc) oldVm)
+                        "runtime code cannot have an abstract length"
+                        [output]
+                    Just newCode -> do
+                      onContractCode $ RuntimeCode (SymbolicRuntimeCode newCode)
 
             -- Case 5: Reverting during a creation?
             FrameReverted output -> do
@@ -2558,19 +2584,19 @@ stackOp3 cost f =
 
 -- * Bytecode data functions
 
-checkJump :: (Integral n) => n -> [Expr EWord] -> EVM ()
+checkJump :: Int -> [Expr EWord] -> EVM ()
 checkJump x xs = do
   theCode <- use (state . code)
   self <- use (state . codeContract)
   theCodeOps <- use (env . contracts . ix self . codeOps)
   theOpIxMap <- use (env . contracts . ix self . opIxMap)
-  let ops = case theCode of
-        InitCode ops' _ -> V.fromList $ LitByte <$> BS.unpack ops'
-        RuntimeCode ops' -> ops'
-      op = do
-        -- TODO: not a big fan of how bounds are checked, change this
-        b <- if x < num (length ops) then ops V.!? num x else Nothing
-        unlitByte b
+  let op = case theCode of
+        InitCode ops _ ->
+          if x > BS.length ops then Nothing else Just $ BS.index ops x
+        RuntimeCode (ConcreteRuntimeCode ops) ->
+          if x > BS.length ops then Nothing else Just $ BS.index ops x
+        RuntimeCode (SymbolicRuntimeCode ops) ->
+          ops V.!? x >>= unlitByte
   case op of
     Nothing -> vmError EVM.BadJumpDestination
     Just b ->
@@ -2606,7 +2632,10 @@ mkOpIxMap (InitCode conc _)
         go v (n, !i, !j, !m) _ =
           {- PUSH data. -}        (n - 1,        i + 1, j,     m >> Vector.write v i j)
 
-mkOpIxMap (RuntimeCode ops)
+mkOpIxMap (RuntimeCode (ConcreteRuntimeCode ops)) =
+  mkOpIxMap (InitCode ops mempty) -- a bit hacky
+
+mkOpIxMap (RuntimeCode (SymbolicRuntimeCode ops))
   = Vector.create $ Vector.new (length ops) >>= \v ->
       let (_, _, _, m) = foldl (go v) (0, 0, 0, return ()) (stripBytecodeMetadataSym $ V.toList ops)
       in m >> return v
@@ -2632,7 +2661,9 @@ vmOp vm =
       (op, pushdata) = case code' of
         InitCode xs' _ ->
           (BS.index xs' i, fmap LitByte $ BS.unpack $ BS.drop i xs')
-        RuntimeCode xs' ->
+        RuntimeCode (ConcreteRuntimeCode xs') ->
+          (BS.index xs' i, fmap LitByte $ BS.unpack $ BS.drop i xs')
+        RuntimeCode (SymbolicRuntimeCode xs') ->
           ( fromMaybe (error "unexpected symbolic code") . unlitByte $ xs' V.! i , V.toList $ V.drop i xs')
   in if (opslen code' < i)
      then Nothing
@@ -2756,25 +2787,24 @@ readOp x _ = case x of
 
 -- Maps operation indicies into a pair of (bytecode index, operation)
 mkCodeOps :: ContractCode -> RegularVector.Vector (Int, Op)
-mkCodeOps (InitCode bytes _) = RegularVector.fromList . toList $ go 0 bytes
+mkCodeOps contractCode =
+  let l = case contractCode of
+            InitCode bytes _ ->
+              LitByte <$> (BS.unpack bytes)
+            RuntimeCode (ConcreteRuntimeCode ops) ->
+              LitByte <$> (BS.unpack $ stripBytecodeMetadata ops)
+            RuntimeCode (SymbolicRuntimeCode ops) ->
+              stripBytecodeMetadataSym $ V.toList ops
+  in RegularVector.fromList . toList $ go 0 l
   where
     go !i !xs =
-      case BS.uncons xs of
-        Nothing ->
-          mempty
-        Just (x, xs') ->
-          let j = opSize x
-          in (i, readOp x (fmap LitByte $ BS.unpack xs')) Seq.<| go (i + j) (BS.drop j xs)
-mkCodeOps (RuntimeCode ops) = RegularVector.fromList . toList $ go' 0 (stripBytecodeMetadataSym $ V.toList ops)
-  where
-    go' !i !xs =
       case uncons xs of
         Nothing ->
           mempty
         Just (x, xs') ->
           let x' = fromMaybe (error "unexpected symbolic code argument") $ unlitByte x
               j = opSize x'
-          in (i, readOp x' xs') Seq.<| go' (i + j) (drop j xs)
+          in (i, readOp x' xs') Seq.<| go (i + j) (drop j xs)
 
 -- * Gas cost calculation helpers
 
@@ -2889,23 +2919,27 @@ log2 x = finiteBitSize x - 1 - countLeadingZeros x
 
 hashcode :: ContractCode -> Expr EWord
 hashcode (InitCode ops args) = keccak $ (ConcreteBuf ops) <> args
-hashcode (RuntimeCode ops) = keccak . Expr.fromList $ ops
+hashcode (RuntimeCode (ConcreteRuntimeCode ops)) = keccak (ConcreteBuf ops)
+hashcode (RuntimeCode (SymbolicRuntimeCode ops)) = keccak . Expr.fromList $ ops
 
 -- | The length of the code ignoring any constructor args.
 -- This represents the region that can contain executable opcodes
 opslen :: ContractCode -> Int
 opslen (InitCode ops _) = BS.length ops
-opslen (RuntimeCode ops) = length ops
+opslen (RuntimeCode (ConcreteRuntimeCode ops)) = BS.length ops
+opslen (RuntimeCode (SymbolicRuntimeCode ops)) = length ops
 
 -- | The length of the code including any constructor args.
 -- This can return an abstract value
 codelen :: ContractCode -> Expr EWord
 codelen c@(InitCode {}) = bufLength $ toBuf c
-codelen (RuntimeCode ops) = Lit . num $ length ops
+codelen (RuntimeCode (ConcreteRuntimeCode ops)) = Lit . num $ BS.length ops
+codelen (RuntimeCode (SymbolicRuntimeCode ops)) = Lit . num $ length ops
 
 toBuf :: ContractCode -> Expr Buf
 toBuf (InitCode ops args) = ConcreteBuf ops <> args
-toBuf (RuntimeCode ops) = Expr.fromList ops
+toBuf (RuntimeCode (ConcreteRuntimeCode ops)) = ConcreteBuf ops
+toBuf (RuntimeCode (SymbolicRuntimeCode ops)) = Expr.fromList ops
 
 
 codeloc :: EVM CodeLocation
@@ -2921,6 +2955,12 @@ toWord64 n =
     then let (W256 (Word256 _ (Word128 _ n'))) = n in Just n'
     else Nothing
 
+toInt :: W256 -> Maybe Int
+toInt n =
+  if n <= num (maxBound :: Int)
+    then let (W256 (Word256 _ (Word128 _ n'))) = n in Just (fromIntegral n')
+    else Nothing
+
 -- * Emacs setup
 
 -- Local Variables:

src/EVM/Dapp.hs

@@ -2,7 +2,7 @@
 
 module EVM.Dapp where
 
-import EVM (Trace, traceContract, traceOpIx, ContractCode(..), Contract(..), codehash, contractcode)
+import EVM (Trace, traceContract, traceOpIx, ContractCode(..), Contract(..), codehash, contractcode, RuntimeCode (..))
 import EVM.ABI (Event, AbiType, SolError)
 import EVM.Debug (srcMapCodePos)
 import EVM.Solidity
@@ -176,7 +176,11 @@ findSrc c dapp = do
 lookupCode :: ContractCode -> DappInfo -> Maybe SolcContract
 lookupCode (InitCode c _) a =
   snd <$> preview (dappSolcByHash . ix (keccak' (stripBytecodeMetadata c))) a
-lookupCode (RuntimeCode c) a = let
+lookupCode (RuntimeCode (ConcreteRuntimeCode c)) a =
+  case snd <$> preview (dappSolcByHash . ix (keccak' (stripBytecodeMetadata c))) a of
+    Just x -> return x
+    Nothing -> snd <$> find (compareCode c . fst) (view dappSolcByCode a)
+lookupCode (RuntimeCode (SymbolicRuntimeCode c)) a = let
     code = BS.pack $ mapMaybe unlitByte $ V.toList c
   in case snd <$> preview (dappSolcByHash . ix (keccak' (stripBytecodeMetadata code))) a of
     Just x -> return x

src/EVM/Dev.hs

@@ -30,7 +30,6 @@ import GHC.Conc
 import System.Exit (exitFailure)
 import qualified EVM.Fetch as Fetch
 import qualified EVM.FeeSchedule as FeeSchedule
-import qualified Data.Vector as V
 
 checkEquiv :: (Typeable a) => Expr a -> Expr a -> IO ()
 checkEquiv a b = withSolvers Z3 1 Nothing $ \s -> do
@@ -363,7 +362,7 @@ vat = do
 initVm :: ByteString -> VM
 initVm bs = vm
   where
-    contractCode = RuntimeCode $ V.fromList $ LitByte <$> unpack bs
+    contractCode = RuntimeCode (ConcreteRuntimeCode bs)
     c = Contract
       { _contractcode = contractCode
       , _balance      = 0

src/EVM/Exec.hs

@@ -45,7 +45,7 @@ vmForEthrunCreation creationCode =
     , vmoptTxAccessList = mempty
     , vmoptAllowFFI = False
     }) & set (env . contracts . at ethrunAddress)
-             (Just (initialContract (RuntimeCode mempty)))
+             (Just (initialContract (RuntimeCode (ConcreteRuntimeCode ""))))
 
 exec :: MonadState VM m => m VMResult
 exec =