Basic support for testing contracts with libraries (#236)

Author: gustavo-grieco

examples/solidity/basic/library.sol

@@ -0,0 +1,23 @@
+library Test{
+    struct Storage{
+        bool flag;
+    }
+
+     function set(Storage storage st) public{
+        st.flag = true;
+    }
+
+ }
+
+contract Contract{
+    using Test for Test.Storage;
+    Test.Storage st;
+
+     function set() public{
+        st.set();
+    }
+
+     function echidna_library_call() external view returns (bool) {
+        return (!st.flag);
+    }
+}

examples/solidity/basic/library.yaml

@@ -0,0 +1,2 @@
+solcLibs: ["basic/library.sol:Test"]
+quiet: true

lib/Echidna/Config.hs

@@ -77,6 +77,7 @@ instance FromJSON EConfig where
                          <*> v .:? "initialBalance" .!= 0xffffffff
                          <*> v .:? "prefix"         .!= "echidna_"
                          <*> v .:? "solcArgs"       .!= ""
+                         <*> v .:? "solcLibs"       .!= []
                          <*> v .:? "quiet"          .!= False)
             <*> tc
             <*> (UIConf <$> v .:? "dashboard" .!= True <*> style)

lib/Echidna/Solidity.hs

@@ -78,6 +78,7 @@ data SolConf = SolConf { _contractAddr    :: Addr    -- ^ Contract address to us
                        , _initialBalance  :: Integer -- ^ Initial balance of deployer and senders
                        , _prefix          :: Text    -- ^ Function name prefix used to denote tests
                        , _solcArgs        :: String  -- ^ Args to pass to @solc@
+                       , _solcLibs        :: [String] -- ^ List of libraries to load, in order.
                        , _quiet           :: Bool    -- ^ Suppress @solc@ output, errors, and warnings
                        }
 makeLenses ''SolConf
@@ -87,21 +88,38 @@ contracts :: (MonadIO m, MonadThrow m, MonadReader x m, Has SolConf x) => FilePa
 contracts fp = do
   a <- view (hasLens . solcArgs)
   q <- view (hasLens . quiet)
-  pure (a, q) >>= liftIO . solc >>= (\case
+  ls <- view (hasLens . solcLibs)
+  pure (a, q, ls) >>= liftIO . solc >>= (\case
     Nothing -> throwM CompileFailure
     Just m  -> pure . toList $ fst m) where
       usual = ["--combined-json=bin-runtime,bin,srcmap,srcmap-runtime,abi,ast", fp]
-      solc (a, q) = do
+      solc (a, q, ls) = do
         stderr <- if q then UseHandle <$> openFile "/dev/null" WriteMode
                        else pure Inherit
         readSolc =<< writeSystemTempFile ""
-                 =<< readCreateProcess (proc "solc" $ usual <> words a) {std_err = stderr} ""
+                 =<< readCreateProcess (proc "solc" $ usual <> words (a ++ linkLibraries ls)) {std_err = stderr} ""
 
 populateAddresses :: [Addr] -> Integer -> VM -> VM
 populateAddresses []     _ vm = vm
 populateAddresses (a:as) b vm = populateAddresses as b (vm & set (env . EVM.contracts . at a) (Just account))
   where account = initialContract (RuntimeCode mempty) & set nonce 1 & set balance (w256 $ fromInteger b)
 
+-- | Address to load the first library
+addrLibrary :: Addr
+addrLibrary = 0xff
+
+ -- | Load a list of solidity contracts as libraries
+loadLibraries :: (MonadIO m, MonadThrow m, MonadReader x m, Has SolConf x)
+              => [SolcContract] -> Addr -> Addr -> VM -> m VM
+loadLibraries []     _  _ vm = return vm
+loadLibraries (l:ls) la d vm = loadLibraries ls (la + 1) d =<< loadRest
+                               where loadRest = execStateT (execTx $ Tx (Right $ l ^. creationCode) d la 0) vm
+
+-- | Generate a string to use as argument in solc to link libraries starting from addrLibrary
+linkLibraries :: [String] -> String
+linkLibraries [] = ""
+linkLibraries ls = "--libraries " ++ concat (imap (\i x -> concat [x, ":", show $ addrLibrary + (toEnum i :: Addr) , ","]) ls)
+
 -- | Given an optional contract name and a list of 'SolcContract's, try to load the specified
 -- contract, or, if not provided, the first contract in the list, into a 'VM' usable for Echidna
 -- testing and extract an ABI and list of tests. Throws exceptions if anything returned doesn't look
@@ -114,23 +132,27 @@ loadSpecified name cs = let ensure l e = if l == mempty then throwM e else pure
   c <- choose cs name
   q <- view (hasLens . quiet)
   liftIO $ do
-    when (isNothing name && length cs > 1) $
+    when (isNothing name && length cs > 1 && not q) $
       putStrLn "Multiple contracts found in file, only analyzing the first"
     unless q . putStrLn $ "Analyzing contract: " <> unpack (c ^. contractName)
 
   -- Local variables
-  (SolConf ca d ads b pref _ _) <- view hasLens
+  (SolConf ca d ads b pref _ libs _) <- view hasLens
   let bc = c ^. creationCode
       blank = populateAddresses (ads |> d) b (vmForEthrunCreation bc)
       abi = liftM2 (,) (view methodName) (fmap snd . view methodInputs) <$> toList (c ^. abiMap)
       (tests, funs) = partition (isPrefixOf pref . fst) abi
 
+  -- Select libraries
+  ls <- mapM (choose cs . Just . pack) libs
+
   -- Make sure everything is ready to use, then ship it
   mapM_ (uncurry ensure) [(abi, NoFuncs), (tests, NoTests), (funs, OnlyTests)] -- ABI checks
   ensure bc (NoBytecode $ c ^. contractName)                                   -- Bytecode check
   case find (not . null . snd) tests of
     Just (t,_) -> throwM $ TestArgsFound t                                     -- Test args check
-    Nothing    -> (, funs, fst <$> tests) <$> execStateT (execTx $ Tx (Right bc) d ca 0) blank
+    Nothing    -> loadLibraries ls addrLibrary d blank >>=
+                    fmap (, funs, fst <$> tests) . execStateT (execTx $ Tx (Right bc) d ca 0)
 
   where choose []    _        = throwM NoContracts
         choose (c:_) Nothing  = return c

src/test/Spec.hs

@@ -111,6 +111,9 @@ integrationTests = testGroup "Solidity Integration Testing"
       [ ("echidna_state3 failed",                 solved "echidna_state3") ]
   , testContract "basic/balance.sol"      (Just "basic/balance.yaml")
       [ ("echidna_balance failed",                passed "echidna_balance") ]
+  , testContract "basic/library.sol"      (Just "basic/library.yaml")
+      [ ("echidna_library_call failed",           solved "echidna_library_call") ]
+
   ]
 
 testContract :: FilePath -> Maybe FilePath -> [(String, Campaign -> Bool)] -> TestTree