Merge branch 'develop'

Conflicts:
	README.md
	evmjit
	libdevcrypto/CryptoPP.cpp
	libethereum/State.cpp
	neth/main.cpp

1 files changed, 762 insertions, 281 deletions

diff --git a/ExpressionCompiler.cpp b/ExpressionCompiler.cpp
index cf641935..a8bc53e0 100644
--- a/ExpressionCompiler.cpp
+++ b/ExpressionCompiler.cpp
@@ -22,7 +22,9 @@
 
 #include <utility>
 #include <numeric>
+#include <boost/range/adaptor/reversed.hpp>
 #include <libdevcore/Common.h>
+#include <libdevcrypto/SHA3.h>
 #include <libsolidity/AST.h>
 #include <libsolidity/ExpressionCompiler.h>
 #include <libsolidity/CompilerContext.h>
@@ -41,64 +43,75 @@ void ExpressionCompiler::compileExpression(CompilerContext& _context, Expression
 	_expression.accept(compiler);
 }
 
-void ExpressionCompiler::appendTypeConversion(CompilerContext& _context,
-											  Type const& _typeOnStack, Type const& _targetType)
+void ExpressionCompiler::appendTypeConversion(CompilerContext& _context, Type const& _typeOnStack,
+											  Type const& _targetType, bool _cleanupNeeded)
 {
 	ExpressionCompiler compiler(_context);
-	compiler.appendTypeConversion(_typeOnStack, _targetType);
+	compiler.appendTypeConversion(_typeOnStack, _targetType, _cleanupNeeded);
+}
+
+void ExpressionCompiler::appendStateVariableAccessor(CompilerContext& _context, VariableDeclaration const& _varDecl, bool _optimize)
+{
+	ExpressionCompiler compiler(_context, _optimize);
+	compiler.appendStateVariableAccessor(_varDecl);
 }
 
 bool ExpressionCompiler::visit(Assignment const& _assignment)
 {
 	_assignment.getRightHandSide().accept(*this);
-	appendTypeConversion(*_assignment.getRightHandSide().getType(), *_assignment.getType());
+	if (_assignment.getType()->isValueType())
+		appendTypeConversion(*_assignment.getRightHandSide().getType(), *_assignment.getType());
 	_assignment.getLeftHandSide().accept(*this);
 	solAssert(m_currentLValue.isValid(), "LValue not retrieved.");
 
 	Token::Value op = _assignment.getAssignmentOperator();
-	if (op != Token::ASSIGN) // compound assignment
+	if (op != Token::Assign) // compound assignment
 	{
+		solAssert(_assignment.getType()->isValueType(), "Compound operators not implemented for non-value types.");
 		if (m_currentLValue.storesReferenceOnStack())
 			m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2;
-		m_currentLValue.retrieveValue(_assignment, true);
+		m_currentLValue.retrieveValue(_assignment.getLocation(), true);
 		appendOrdinaryBinaryOperatorCode(Token::AssignmentToBinaryOp(op), *_assignment.getType());
 		if (m_currentLValue.storesReferenceOnStack())
 			m_context << eth::Instruction::SWAP1;
 	}
-	m_currentLValue.storeValue(_assignment);
+	m_currentLValue.storeValue(*_assignment.getRightHandSide().getType(), _assignment.getLocation());
 	m_currentLValue.reset();
 
 	return false;
 }
 
-void ExpressionCompiler::endVisit(UnaryOperation const& _unaryOperation)
+bool ExpressionCompiler::visit(UnaryOperation const& _unaryOperation)
 {
 	//@todo type checking and creating code for an operator should be in the same place:
 	// the operator should know how to convert itself and to which types it applies, so
 	// put this code together with "Type::acceptsBinary/UnaryOperator" into a class that
 	// represents the operator
+	if (_unaryOperation.getType()->getCategory() == Type::Category::IntegerConstant)
+	{
+		m_context << _unaryOperation.getType()->literalValue(nullptr);
+		return false;
+	}
+
+	_unaryOperation.getSubExpression().accept(*this);
+
 	switch (_unaryOperation.getOperator())
 	{
-	case Token::NOT: // !
+	case Token::Not: // !
 		m_context << eth::Instruction::ISZERO;
 		break;
-	case Token::BIT_NOT: // ~
+	case Token::BitNot: // ~
 		m_context << eth::Instruction::NOT;
 		break;
-	case Token::DELETE: // delete
-		// @todo semantics change for complex types
+	case Token::Delete: // delete
 		solAssert(m_currentLValue.isValid(), "LValue not retrieved.");
-
-		m_context << u256(0);
-		if (m_currentLValue.storesReferenceOnStack())
-			m_context << eth::Instruction::SWAP1;
-		m_currentLValue.storeValue(_unaryOperation);
+		m_currentLValue.setToZero(_unaryOperation.getLocation());
 		m_currentLValue.reset();
 		break;
-	case Token::INC: // ++ (pre- or postfix)
-	case Token::DEC: // -- (pre- or postfix)
+	case Token::Inc: // ++ (pre- or postfix)
+	case Token::Dec: // -- (pre- or postfix)
 		solAssert(m_currentLValue.isValid(), "LValue not retrieved.");
-		m_currentLValue.retrieveValue(_unaryOperation);
+		m_currentLValue.retrieveValue(_unaryOperation.getLocation());
 		if (!_unaryOperation.isPrefixOperation())
 		{
 			if (m_currentLValue.storesReferenceOnStack())
@@ -107,7 +120,7 @@ void ExpressionCompiler::endVisit(UnaryOperation const& _unaryOperation)
 				m_context << eth::Instruction::DUP1;
 		}
 		m_context << u256(1);
-		if (_unaryOperation.getOperator() == Token::INC)
+		if (_unaryOperation.getOperator() == Token::Inc)
 			m_context << eth::Instruction::ADD;
 		else
 			m_context << eth::Instruction::SWAP1 << eth::Instruction::SUB; // @todo avoid the swap
@@ -115,19 +128,21 @@ void ExpressionCompiler::endVisit(UnaryOperation const& _unaryOperation)
 		// Stack for postfix: *ref [ref] (*ref)+-1
 		if (m_currentLValue.storesReferenceOnStack())
 			m_context << eth::Instruction::SWAP1;
-		m_currentLValue.storeValue(_unaryOperation, !_unaryOperation.isPrefixOperation());
+		m_currentLValue.storeValue(*_unaryOperation.getType(), _unaryOperation.getLocation(),
+								   !_unaryOperation.isPrefixOperation());
 		m_currentLValue.reset();
 		break;
-	case Token::ADD: // +
+	case Token::Add: // +
 		// unary add, so basically no-op
 		break;
-	case Token::SUB: // -
+	case Token::Sub: // -
 		m_context << u256(0) << eth::Instruction::SUB;
 		break;
 	default:
 		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Invalid unary operator: " +
 																		 string(Token::toString(_unaryOperation.getOperator()))));
 	}
+	return false;
 }
 
 bool ExpressionCompiler::visit(BinaryOperation const& _binaryOperation)
@@ -135,21 +150,23 @@ bool ExpressionCompiler::visit(BinaryOperation const& _binaryOperation)
 	Expression const& leftExpression = _binaryOperation.getLeftExpression();
 	Expression const& rightExpression = _binaryOperation.getRightExpression();
 	Type const& commonType = _binaryOperation.getCommonType();
-	Token::Value const op = _binaryOperation.getOperator();
+	Token::Value const c_op = _binaryOperation.getOperator();
 
-	if (op == Token::AND || op == Token::OR) // special case: short-circuiting
+	if (c_op == Token::And || c_op == Token::Or) // special case: short-circuiting
 		appendAndOrOperatorCode(_binaryOperation);
+	else if (commonType.getCategory() == Type::Category::IntegerConstant)
+		m_context << commonType.literalValue(nullptr);
 	else
 	{
-		bool cleanupNeeded = false;
-		if (commonType.getCategory() == Type::Category::INTEGER)
-			if (Token::isCompareOp(op) || op == Token::DIV || op == Token::MOD)
-				cleanupNeeded = true;
+		bool cleanupNeeded = commonType.getCategory() == Type::Category::Integer &&
+								(Token::isCompareOp(c_op) || c_op == Token::Div || c_op == Token::Mod);
 
 		// for commutative operators, push the literal as late as possible to allow improved optimization
-		//@todo this has to be extended for literal expressions
-		bool swap = (m_optimize && Token::isCommutativeOp(op) && dynamic_cast<Literal const*>(&rightExpression)
-					 && !dynamic_cast<Literal const*>(&leftExpression));
+		auto isLiteral = [](Expression const& _e)
+		{
+			return dynamic_cast<Literal const*>(&_e) || _e.getType()->getCategory() == Type::Category::IntegerConstant;
+		};
+		bool swap = m_optimize && Token::isCommutativeOp(c_op) && isLiteral(rightExpression) && !isLiteral(leftExpression);
 		if (swap)
 		{
 			leftExpression.accept(*this);
@@ -164,10 +181,10 @@ bool ExpressionCompiler::visit(BinaryOperation const& _binaryOperation)
 			leftExpression.accept(*this);
 			appendTypeConversion(*leftExpression.getType(), commonType, cleanupNeeded);
 		}
-		if (Token::isCompareOp(op))
-			appendCompareOperatorCode(op, commonType);
+		if (Token::isCompareOp(c_op))
+			appendCompareOperatorCode(c_op, commonType);
 		else
-			appendOrdinaryBinaryOperatorCode(op, commonType);
+			appendOrdinaryBinaryOperatorCode(c_op, commonType);
 	}
 
 	// do not visit the child nodes, we already did that explicitly
@@ -181,25 +198,39 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 	{
 		//@todo struct construction
 		solAssert(_functionCall.getArguments().size() == 1, "");
+		solAssert(_functionCall.getNames().empty(), "");
 		Expression const& firstArgument = *_functionCall.getArguments().front();
 		firstArgument.accept(*this);
-		if (firstArgument.getType()->getCategory() == Type::Category::CONTRACT &&
-				_functionCall.getType()->getCategory() == Type::Category::INTEGER)
-		{
-			// explicit type conversion contract -> address, nothing to do.
-		}
-		else
-			appendTypeConversion(*firstArgument.getType(), *_functionCall.getType());
+		appendTypeConversion(*firstArgument.getType(), *_functionCall.getType());
 	}
 	else
 	{
 		FunctionType const& function = dynamic_cast<FunctionType const&>(*_functionCall.getExpression().getType());
-		vector<ASTPointer<Expression const>> arguments = _functionCall.getArguments();
-		solAssert(arguments.size() == function.getParameterTypes().size(), "");
+		TypePointers const& parameterTypes = function.getParameterTypes();
+		vector<ASTPointer<Expression const>> const& callArguments = _functionCall.getArguments();
+		vector<ASTPointer<ASTString>> const& callArgumentNames = _functionCall.getNames();
+		if (!function.takesArbitraryParameters())
+			solAssert(callArguments.size() == parameterTypes.size(), "");
+
+		vector<ASTPointer<Expression const>> arguments;
+		if (callArgumentNames.empty())
+			// normal arguments
+			arguments = callArguments;
+		else
+			// named arguments
+			for (auto const& parameterName: function.getParameterNames())
+			{
+				bool found = false;
+				for (size_t j = 0; j < callArgumentNames.size() && !found; j++)
+					if ((found = (parameterName == *callArgumentNames[j])))
+						// we found the actual parameter position
+						arguments.push_back(callArguments[j]);
+				solAssert(found, "");
+			}
 
 		switch (function.getLocation())
 		{
-		case Location::INTERNAL:
+		case Location::Internal:
 		{
 			// Calling convention: Caller pushes return address and arguments
 			// Callee removes them and pushes return values
@@ -217,7 +248,7 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 
 			unsigned returnParametersSize = CompilerUtils::getSizeOnStack(function.getReturnParameterTypes());
 			// callee adds return parameters, but removes arguments and return label
-			m_context.adjustStackOffset(returnParametersSize - CompilerUtils::getSizeOnStack(arguments) - 1);
+			m_context.adjustStackOffset(returnParametersSize - CompilerUtils::getSizeOnStack(function.getParameterTypes()) - 1);
 
 			// @todo for now, the return value of a function is its first return value, so remove
 			// all others
@@ -225,50 +256,143 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 				CompilerUtils(m_context).popStackElement(*function.getReturnParameterTypes()[i]);
 			break;
 		}
-		case Location::EXTERNAL:
-		case Location::BARE:
+		case Location::External:
+		case Location::Bare:
+			_functionCall.getExpression().accept(*this);
+			appendExternalFunctionCall(function, arguments, function.getLocation() == Location::Bare);
+			break;
+		case Location::Creation:
 		{
-			FunctionCallOptions options;
-			options.bare = function.getLocation() == Location::BARE;
-			options.obtainAddress = [&]() { _functionCall.getExpression().accept(*this); };
-			appendExternalFunctionCall(function, arguments, options);
+			_functionCall.getExpression().accept(*this);
+			solAssert(!function.gasSet(), "Gas limit set for contract creation.");
+			solAssert(function.getReturnParameterTypes().size() == 1, "");
+			ContractDefinition const& contract = dynamic_cast<ContractType const&>(
+							*function.getReturnParameterTypes().front()).getContractDefinition();
+			// copy the contract's code into memory
+			bytes const& bytecode = m_context.getCompiledContract(contract);
+			m_context << u256(bytecode.size());
+			//@todo could be done by actually appending the Assembly, but then we probably need to compile
+			// multiple times. Will revisit once external fuctions are inlined.
+			m_context.appendData(bytecode);
+			//@todo copy to memory position 0, shift as soon as we use memory
+			m_context << u256(0) << eth::Instruction::CODECOPY;
+
+			m_context << u256(bytecode.size());
+			appendArgumentsCopyToMemory(arguments, function.getParameterTypes());
+			// size, offset, endowment
+			m_context << u256(0);
+			if (function.valueSet())
+				m_context << eth::dupInstruction(3);
+			else
+				m_context << u256(0);
+			m_context << eth::Instruction::CREATE;
+			if (function.valueSet())
+				m_context << eth::swapInstruction(1) << eth::Instruction::POP;
 			break;
 		}
-		case Location::SEND:
+		case Location::SetGas:
 		{
-			FunctionCallOptions options;
-			options.bare = true;
-			options.obtainAddress = [&]() { _functionCall.getExpression().accept(*this); };
-			options.obtainValue = [&]() { arguments.front()->accept(*this); };
-			appendExternalFunctionCall(FunctionType({}, {}, Location::EXTERNAL), {}, options);
+			// stack layout: contract_address function_id [gas] [value]
+			_functionCall.getExpression().accept(*this);
+			arguments.front()->accept(*this);
+			appendTypeConversion(*arguments.front()->getType(), IntegerType(256), true);
+			// Note that function is not the original function, but the ".gas" function.
+			// Its values of gasSet and valueSet is equal to the original function's though.
+			unsigned stackDepth = (function.gasSet() ? 1 : 0) + (function.valueSet() ? 1 : 0);
+			if (stackDepth > 0)
+				m_context << eth::swapInstruction(stackDepth);
+			if (function.gasSet())
+				m_context << eth::Instruction::POP;
 			break;
 		}
-		case Location::SUICIDE:
+		case Location::SetValue:
+			// stack layout: contract_address function_id [gas] [value]
+			_functionCall.getExpression().accept(*this);
+			// Note that function is not the original function, but the ".value" function.
+			// Its values of gasSet and valueSet is equal to the original function's though.
+			if (function.valueSet())
+				m_context << eth::Instruction::POP;
+			arguments.front()->accept(*this);
+			break;
+		case Location::Send:
+			_functionCall.getExpression().accept(*this);
+			m_context << u256(0); // 0 gas, we do not want to execute code
+			arguments.front()->accept(*this);
+			appendTypeConversion(*arguments.front()->getType(),
+								 *function.getParameterTypes().front(), true);
+			appendExternalFunctionCall(FunctionType(TypePointers{}, TypePointers{},
+													Location::External, false, true, true), {}, true);
+			break;
+		case Location::Suicide:
 			arguments.front()->accept(*this);
-			//@todo might not be necessary
 			appendTypeConversion(*arguments.front()->getType(), *function.getParameterTypes().front(), true);
 			m_context << eth::Instruction::SUICIDE;
 			break;
 		case Location::SHA3:
-			arguments.front()->accept(*this);
-			appendTypeConversion(*arguments.front()->getType(), *function.getParameterTypes().front(), true);
-			// @todo move this once we actually use memory
-			CompilerUtils(m_context).storeInMemory(0);
-			m_context << u256(32) << u256(0) << eth::Instruction::SHA3;
+		{
+			m_context << u256(0);
+			appendArgumentsCopyToMemory(arguments, TypePointers(), function.padArguments());
+			m_context << u256(0) << eth::Instruction::SHA3;
+			break;
+		}
+		case Location::Log0:
+		case Location::Log1:
+		case Location::Log2:
+		case Location::Log3:
+		case Location::Log4:
+		{
+			unsigned logNumber = int(function.getLocation()) - int(Location::Log0);
+			for (unsigned arg = logNumber; arg > 0; --arg)
+			{
+				arguments[arg]->accept(*this);
+				appendTypeConversion(*arguments[arg]->getType(), *function.getParameterTypes()[arg], true);
+			}
+			m_context << u256(0);
+			appendExpressionCopyToMemory(*function.getParameterTypes().front(), *arguments.front());
+			m_context << u256(0) << eth::logInstruction(logNumber);
+			break;
+		}
+		case Location::Event:
+		{
+			_functionCall.getExpression().accept(*this);
+			auto const& event = dynamic_cast<EventDefinition const&>(function.getDeclaration());
+			unsigned numIndexed = 0;
+			// All indexed arguments go to the stack
+			for (unsigned arg = arguments.size(); arg > 0; --arg)
+				if (event.getParameters()[arg - 1]->isIndexed())
+				{
+					++numIndexed;
+					arguments[arg - 1]->accept(*this);
+					appendTypeConversion(*arguments[arg - 1]->getType(),
+										 *function.getParameterTypes()[arg - 1], true);
+				}
+			m_context << u256(h256::Arith(dev::sha3(function.getCanonicalSignature(event.getName()))));
+			++numIndexed;
+			solAssert(numIndexed <= 4, "Too many indexed arguments.");
+			// Copy all non-indexed arguments to memory (data)
+			m_context << u256(0);
+			for (unsigned arg = 0; arg < arguments.size(); ++arg)
+				if (!event.getParameters()[arg]->isIndexed())
+					appendExpressionCopyToMemory(*function.getParameterTypes()[arg], *arguments[arg]);
+			m_context << u256(0) << eth::logInstruction(numIndexed);
 			break;
-		case Location::ECRECOVER:
+		}
+		case Location::BlockHash:
+		{
+			arguments[0]->accept(*this);
+			appendTypeConversion(*arguments[0]->getType(), *function.getParameterTypes()[0], true);
+			m_context << eth::Instruction::BLOCKHASH;
+			break;
+		}
+		case Location::ECRecover:
 		case Location::SHA256:
 		case Location::RIPEMD160:
 		{
-			static const map<Location, u256> contractAddresses{{Location::ECRECOVER, 1},
+			static const map<Location, u256> contractAddresses{{Location::ECRecover, 1},
 															   {Location::SHA256, 2},
 															   {Location::RIPEMD160, 3}};
-			u256 contractAddress = contractAddresses.find(function.getLocation())->second;
-			FunctionCallOptions options;
-			options.bare = true;
-			options.obtainAddress = [&]() { m_context << contractAddress; };
-			options.packDensely = false;
-			appendExternalFunctionCall(function, arguments, options);
+			m_context << contractAddresses.find(function.getLocation())->second;
+			appendExternalFunctionCall(function, arguments, true);
 			break;
 		}
 		default:
@@ -278,39 +402,9 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 	return false;
 }
 
-bool ExpressionCompiler::visit(NewExpression const& _newExpression)
-{
-	ContractType const* type = dynamic_cast<ContractType const*>(_newExpression.getType().get());
-	solAssert(type, "");
-	TypePointers const& types = type->getConstructorType()->getParameterTypes();
-	vector<ASTPointer<Expression const>> arguments = _newExpression.getArguments();
-	solAssert(arguments.size() == types.size(), "");
-
-	// copy the contracts code into memory
-	bytes const& bytecode = m_context.getCompiledContract(*_newExpression.getContract());
-	m_context << u256(bytecode.size());
-	//@todo could be done by actually appending the Assembly, but then we probably need to compile
-	// multiple times. Will revisit once external fuctions are inlined.
-	m_context.appendData(bytecode);
-	//@todo copy to memory position 0, shift as soon as we use memory
-	m_context << u256(0) << eth::Instruction::CODECOPY;
-
-	unsigned dataOffset = bytecode.size();
-	for (unsigned i = 0; i < arguments.size(); ++i)
-	{
-		arguments[i]->accept(*this);
-		appendTypeConversion(*arguments[i]->getType(), *types[i]);
-		unsigned const numBytes = types[i]->getCalldataEncodedSize();
-		if (numBytes > 32)
-			BOOST_THROW_EXCEPTION(CompilerError()
-								  << errinfo_sourceLocation(arguments[i]->getLocation())
-								  << errinfo_comment("Type " + types[i]->toString() + " not yet supported."));
-		bool const leftAligned = types[i]->getCategory() == Type::Category::STRING;
-		CompilerUtils(m_context).storeInMemory(dataOffset, numBytes, leftAligned);
-		dataOffset += numBytes;
-	}
-	// size, offset, endowment
-	m_context << u256(dataOffset) << u256(0) << u256(0) << eth::Instruction::CREATE;
+bool ExpressionCompiler::visit(NewExpression const&)
+{
+	// code is created for the function call (CREATION) only
 	return false;
 }
 
@@ -319,33 +413,51 @@ void ExpressionCompiler::endVisit(MemberAccess const& _memberAccess)
 	ASTString const& member = _memberAccess.getMemberName();
 	switch (_memberAccess.getExpression().getType()->getCategory())
 	{
-	case Type::Category::INTEGER:
+	case Type::Category::Contract:
+	{
+		bool alsoSearchInteger = false;
+		ContractType const& type = dynamic_cast<ContractType const&>(*_memberAccess.getExpression().getType());
+		if (type.isSuper())
+			m_context << m_context.getSuperFunctionEntryLabel(member, type.getContractDefinition()).pushTag();
+		else
+		{
+			// ordinary contract type
+			u256 identifier = type.getFunctionIdentifier(member);
+			if (identifier != Invalid256)
+			{
+				appendTypeConversion(type, IntegerType(0, IntegerType::Modifier::Address), true);
+				m_context << identifier;
+			}
+			else
+				// not found in contract, search in members inherited from address
+				alsoSearchInteger = true;
+		}
+		if (!alsoSearchInteger)
+			break;
+	}
+	case Type::Category::Integer:
 		if (member == "balance")
 		{
 			appendTypeConversion(*_memberAccess.getExpression().getType(),
-								 IntegerType(0, IntegerType::Modifier::ADDRESS), true);
+								 IntegerType(0, IntegerType::Modifier::Address), true);
 			m_context << eth::Instruction::BALANCE;
 		}
 		else if (member == "send" || member.substr(0, min<size_t>(member.size(), 4)) == "call")
 			appendTypeConversion(*_memberAccess.getExpression().getType(),
-								 IntegerType(0, IntegerType::Modifier::ADDRESS), true);
+								 IntegerType(0, IntegerType::Modifier::Address), true);
 		else
 			BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Invalid member access to integer."));
 		break;
-	case Type::Category::CONTRACT:
-	{
-		ContractType const& type = dynamic_cast<ContractType const&>(*_memberAccess.getExpression().getType());
-		m_context << type.getFunctionIndex(member);
+	case Type::Category::Function:
+		solAssert(!!_memberAccess.getExpression().getType()->getMemberType(member),
+				 "Invalid member access to function.");
 		break;
-	}
-	case Type::Category::MAGIC:
+	case Type::Category::Magic:
 		// we can ignore the kind of magic and only look at the name of the member
 		if (member == "coinbase")
 			m_context << eth::Instruction::COINBASE;
 		else if (member == "timestamp")
 			m_context << eth::Instruction::TIMESTAMP;
-		else if (member == "prevhash")
-			m_context << eth::Instruction::PREVHASH;
 		else if (member == "difficulty")
 			m_context << eth::Instruction::DIFFICULTY;
 		else if (member == "number")
@@ -362,17 +474,64 @@ void ExpressionCompiler::endVisit(MemberAccess const& _memberAccess)
 			m_context << eth::Instruction::GAS;
 		else if (member == "gasprice")
 			m_context << eth::Instruction::GASPRICE;
+		else if (member == "data")
+			m_context << u256(0) << eth::Instruction::CALLDATASIZE;
 		else
 			BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Unknown magic member."));
 		break;
-	case Type::Category::STRUCT:
+	case Type::Category::Struct:
 	{
 		StructType const& type = dynamic_cast<StructType const&>(*_memberAccess.getExpression().getType());
 		m_context << type.getStorageOffsetOfMember(member) << eth::Instruction::ADD;
-		m_currentLValue = LValue(m_context, LValue::STORAGE, *_memberAccess.getType());
+		m_currentLValue = LValue(m_context, LValue::LValueType::Storage, _memberAccess.getType());
 		m_currentLValue.retrieveValueIfLValueNotRequested(_memberAccess);
 		break;
 	}
+	case Type::Category::Enum:
+	{
+		EnumType const& type = dynamic_cast<EnumType const&>(*_memberAccess.getExpression().getType());
+		m_context << type.getMemberValue(_memberAccess.getMemberName());
+		break;
+	}
+	case Type::Category::TypeType:
+	{
+		TypeType const& type = dynamic_cast<TypeType const&>(*_memberAccess.getExpression().getType());
+		if (!type.getMembers().getMemberType(member))
+			BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Invalid member access to " + type.toString()));
+
+		if (auto contractType = dynamic_cast<ContractType const*>(type.getActualType().get()))
+		{
+			ContractDefinition const& contract = contractType->getContractDefinition();
+			for (ASTPointer<FunctionDefinition> const& function: contract.getDefinedFunctions())
+				if (function->getName() == member)
+				{
+					m_context << m_context.getFunctionEntryLabel(*function).pushTag();
+					return;
+				}
+			solAssert(false, "Function not found in member access.");
+		}
+		else if (auto enumType = dynamic_cast<EnumType const*>(type.getActualType().get()))
+			m_context << enumType->getMemberValue(_memberAccess.getMemberName());
+		break;
+	}
+	case Type::Category::ByteArray:
+	{
+		solAssert(member == "length", "Illegal bytearray member.");
+		auto const& type = dynamic_cast<ByteArrayType const&>(*_memberAccess.getExpression().getType());
+		switch (type.getLocation())
+		{
+		case ByteArrayType::Location::CallData:
+			m_context << eth::Instruction::SWAP1 << eth::Instruction::POP;
+			break;
+		case ByteArrayType::Location::Storage:
+			m_context << eth::Instruction::SLOAD;
+			break;
+		default:
+			solAssert(false, "Unsupported byte array location.");
+			break;
+		}
+		break;
+	}
 	default:
 		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Member access to unknown type."));
 	}
@@ -381,16 +540,19 @@ void ExpressionCompiler::endVisit(MemberAccess const& _memberAccess)
 bool ExpressionCompiler::visit(IndexAccess const& _indexAccess)
 {
 	_indexAccess.getBaseExpression().accept(*this);
-	_indexAccess.getIndexExpression().accept(*this);
-	appendTypeConversion(*_indexAccess.getIndexExpression().getType(),
-						 *dynamic_cast<MappingType const&>(*_indexAccess.getBaseExpression().getType()).getKeyType(),
-						 true);
-	// @todo move this once we actually use memory
-	CompilerUtils(m_context).storeInMemory(0);
-	CompilerUtils(m_context).storeInMemory(32);
-	m_context << u256(64) << u256(0) << eth::Instruction::SHA3;
-
-	m_currentLValue = LValue(m_context, LValue::STORAGE, *_indexAccess.getType());
+
+	Type const& baseType = *_indexAccess.getBaseExpression().getType();
+	solAssert(baseType.getCategory() == Type::Category::Mapping, "");
+	Type const& keyType = *dynamic_cast<MappingType const&>(baseType).getKeyType();
+	m_context << u256(0);
+	appendExpressionCopyToMemory(keyType, _indexAccess.getIndexExpression());
+	solAssert(baseType.getSizeOnStack() == 1,
+			  "Unexpected: Not exactly one stack slot taken by subscriptable expression.");
+	m_context << eth::Instruction::SWAP1;
+	appendTypeMoveToMemory(IntegerType(256));
+	m_context << u256(0) << eth::Instruction::SHA3;
+
+	m_currentLValue = LValue(m_context, LValue::LValueType::Storage, _indexAccess.getType());
 	m_currentLValue.retrieveValueIfLValueNotRequested(_indexAccess);
 
 	return false;
@@ -401,32 +563,44 @@ void ExpressionCompiler::endVisit(Identifier const& _identifier)
 	Declaration const* declaration = _identifier.getReferencedDeclaration();
 	if (MagicVariableDeclaration const* magicVar = dynamic_cast<MagicVariableDeclaration const*>(declaration))
 	{
-		if (magicVar->getType()->getCategory() == Type::Category::CONTRACT) // must be "this"
-			m_context << eth::Instruction::ADDRESS;
-		return;
+		if (magicVar->getType()->getCategory() == Type::Category::Contract)
+			// "this" or "super"
+			if (!dynamic_cast<ContractType const&>(*magicVar->getType()).isSuper())
+				m_context << eth::Instruction::ADDRESS;
 	}
-	if (FunctionDefinition const* functionDef = dynamic_cast<FunctionDefinition const*>(declaration))
-	{
-		m_context << m_context.getFunctionEntryLabel(*functionDef).pushTag();
-		return;
-	}
-	if (dynamic_cast<VariableDeclaration const*>(declaration))
+	else if (FunctionDefinition const* functionDef = dynamic_cast<FunctionDefinition const*>(declaration))
+		m_context << m_context.getVirtualFunctionEntryLabel(*functionDef).pushTag();
+	else if (dynamic_cast<VariableDeclaration const*>(declaration))
 	{
 		m_currentLValue.fromIdentifier(_identifier, *declaration);
 		m_currentLValue.retrieveValueIfLValueNotRequested(_identifier);
-		return;
 	}
-	BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Identifier type not expected in expression context."));
+	else if (dynamic_cast<ContractDefinition const*>(declaration))
+	{
+		// no-op
+	}
+	else if (dynamic_cast<EventDefinition const*>(declaration))
+	{
+		// no-op
+	}
+	else if (dynamic_cast<EnumDefinition const*>(declaration))
+	{
+		// no-op
+	}
+	else
+	{
+		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Identifier type not expected in expression context."));
+	}
 }
 
 void ExpressionCompiler::endVisit(Literal const& _literal)
 {
 	switch (_literal.getType()->getCategory())
 	{
-	case Type::Category::INTEGER:
-	case Type::Category::BOOL:
-	case Type::Category::STRING:
-		m_context << _literal.getType()->literalValue(_literal);
+	case Type::Category::IntegerConstant:
+	case Type::Category::Bool:
+	case Type::Category::String:
+		m_context << _literal.getType()->literalValue(&_literal);
 		break;
 	default:
 		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Only integer, boolean and string literals implemented for now."));
@@ -435,12 +609,12 @@ void ExpressionCompiler::endVisit(Literal const& _literal)
 
 void ExpressionCompiler::appendAndOrOperatorCode(BinaryOperation const& _binaryOperation)
 {
-	Token::Value const op = _binaryOperation.getOperator();
-	solAssert(op == Token::OR || op == Token::AND, "");
+	Token::Value const c_op = _binaryOperation.getOperator();
+	solAssert(c_op == Token::Or || c_op == Token::And, "");
 
 	_binaryOperation.getLeftExpression().accept(*this);
 	m_context << eth::Instruction::DUP1;
-	if (op == Token::AND)
+	if (c_op == Token::And)
 		m_context << eth::Instruction::ISZERO;
 	eth::AssemblyItem endLabel = m_context.appendConditionalJump();
 	m_context << eth::Instruction::POP;
@@ -450,32 +624,32 @@ void ExpressionCompiler::appendAndOrOperatorCode(BinaryOperation const& _binaryO
 
 void ExpressionCompiler::appendCompareOperatorCode(Token::Value _operator, Type const& _type)
 {
-	if (_operator == Token::EQ || _operator == Token::NE)
+	if (_operator == Token::Equal || _operator == Token::NotEqual)
 	{
 		m_context << eth::Instruction::EQ;
-		if (_operator == Token::NE)
+		if (_operator == Token::NotEqual)
 			m_context << eth::Instruction::ISZERO;
 	}
 	else
 	{
 		IntegerType const& type = dynamic_cast<IntegerType const&>(_type);
-		bool const isSigned = type.isSigned();
+		bool const c_isSigned = type.isSigned();
 
 		switch (_operator)
 		{
-		case Token::GTE:
-			m_context << (isSigned ? eth::Instruction::SLT : eth::Instruction::LT)
+		case Token::GreaterThanOrEqual:
+			m_context << (c_isSigned ? eth::Instruction::SLT : eth::Instruction::LT)
 					  << eth::Instruction::ISZERO;
 			break;
-		case Token::LTE:
-			m_context << (isSigned ? eth::Instruction::SGT : eth::Instruction::GT)
+		case Token::LessThanOrEqual:
+			m_context << (c_isSigned ? eth::Instruction::SGT : eth::Instruction::GT)
 					  << eth::Instruction::ISZERO;
 			break;
-		case Token::GT:
-			m_context << (isSigned ? eth::Instruction::SGT : eth::Instruction::GT);
+		case Token::GreaterThan:
+			m_context << (c_isSigned ? eth::Instruction::SGT : eth::Instruction::GT);
 			break;
-		case Token::LT:
-			m_context << (isSigned ? eth::Instruction::SLT : eth::Instruction::LT);
+		case Token::LessThan:
+			m_context << (c_isSigned ? eth::Instruction::SLT : eth::Instruction::LT);
 			break;
 		default:
 			BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Unknown comparison operator."));
@@ -498,24 +672,27 @@ void ExpressionCompiler::appendOrdinaryBinaryOperatorCode(Token::Value _operator
 void ExpressionCompiler::appendArithmeticOperatorCode(Token::Value _operator, Type const& _type)
 {
 	IntegerType const& type = dynamic_cast<IntegerType const&>(_type);
-	bool const isSigned = type.isSigned();
+	bool const c_isSigned = type.isSigned();
 
 	switch (_operator)
 	{
-	case Token::ADD:
+	case Token::Add:
 		m_context << eth::Instruction::ADD;
 		break;
-	case Token::SUB:
+	case Token::Sub:
 		m_context << eth::Instruction::SUB;
 		break;
-	case Token::MUL:
+	case Token::Mul:
 		m_context << eth::Instruction::MUL;
 		break;
-	case Token::DIV:
-		m_context  << (isSigned ? eth::Instruction::SDIV : eth::Instruction::DIV);
+	case Token::Div:
+		m_context  << (c_isSigned ? eth::Instruction::SDIV : eth::Instruction::DIV);
 		break;
-	case Token::MOD:
-		m_context << (isSigned ? eth::Instruction::SMOD : eth::Instruction::MOD);
+	case Token::Mod:
+		m_context << (c_isSigned ? eth::Instruction::SMOD : eth::Instruction::MOD);
+		break;
+	case Token::Exp:
+		m_context << eth::Instruction::EXP;
 		break;
 	default:
 		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Unknown arithmetic operator."));
@@ -526,13 +703,13 @@ void ExpressionCompiler::appendBitOperatorCode(Token::Value _operator)
 {
 	switch (_operator)
 	{
-	case Token::BIT_OR:
+	case Token::BitOr:
 		m_context << eth::Instruction::OR;
 		break;
-	case Token::BIT_AND:
+	case Token::BitAnd:
 		m_context << eth::Instruction::AND;
 		break;
-	case Token::BIT_XOR:
+	case Token::BitXor:
 		m_context << eth::Instruction::XOR;
 		break;
 	default:
@@ -562,12 +739,82 @@ void ExpressionCompiler::appendTypeConversion(Type const& _typeOnStack, Type con
 
 	if (_typeOnStack == _targetType && !_cleanupNeeded)
 		return;
-	if (_typeOnStack.getCategory() == Type::Category::INTEGER)
-		appendHighBitsCleanup(dynamic_cast<IntegerType const&>(_typeOnStack));
-	else if (_typeOnStack.getCategory() == Type::Category::STRING)
+	Type::Category stackTypeCategory = _typeOnStack.getCategory();
+	Type::Category targetTypeCategory = _targetType.getCategory();
+
+	if (stackTypeCategory == Type::Category::String)
+	{
+		StaticStringType const& typeOnStack = dynamic_cast<StaticStringType const&>(_typeOnStack);
+		if (targetTypeCategory == Type::Category::Integer)
+		{
+			// conversion from string to hash. no need to clean the high bit
+			// only to shift right because of opposite alignment
+			IntegerType const& targetIntegerType = dynamic_cast<IntegerType const&>(_targetType);
+			solAssert(targetIntegerType.isHash(), "Only conversion between String and Hash is allowed.");
+			solAssert(targetIntegerType.getNumBits() == typeOnStack.getNumBytes() * 8, "The size should be the same.");
+			m_context << (u256(1) << (256 - typeOnStack.getNumBytes() * 8)) << eth::Instruction::SWAP1 << eth::Instruction::DIV;
+		}
+		else
+		{
+			// clear lower-order bytes for conversion to shorter strings - we always clean
+			solAssert(targetTypeCategory == Type::Category::String, "Invalid type conversion requested.");
+			StaticStringType const& targetType = dynamic_cast<StaticStringType const&>(_targetType);
+			if (targetType.getNumBytes() < typeOnStack.getNumBytes())
+			{
+				if (targetType.getNumBytes() == 0)
+					m_context << eth::Instruction::DUP1 << eth::Instruction::XOR;
+				else
+					m_context << (u256(1) << (256 - targetType.getNumBytes() * 8))
+							  << eth::Instruction::DUP1 << eth::Instruction::SWAP2
+							  << eth::Instruction::DIV << eth::Instruction::MUL;
+			}
+		}
+	}
+	else if (stackTypeCategory == Type::Category::Enum)
+		solAssert(targetTypeCategory == Type::Category::Integer ||
+			targetTypeCategory == Type::Category::Enum, "");
+	else if (stackTypeCategory == Type::Category::Integer || stackTypeCategory == Type::Category::Contract ||
+			 stackTypeCategory == Type::Category::IntegerConstant)
 	{
-		// nothing to do, strings are high-order-bit-aligned
-		//@todo clear lower-order bytes if we allow explicit conversion to shorter strings
+		if (targetTypeCategory == Type::Category::String && stackTypeCategory == Type::Category::Integer)
+		{
+			// conversion from hash to string. no need to clean the high bit
+			// only to shift left because of opposite alignment
+			StaticStringType const& targetStringType = dynamic_cast<StaticStringType const&>(_targetType);
+			IntegerType const& typeOnStack = dynamic_cast<IntegerType const&>(_typeOnStack);
+			solAssert(typeOnStack.isHash(), "Only conversion between String and Hash is allowed.");
+			solAssert(typeOnStack.getNumBits() == targetStringType.getNumBytes() * 8, "The size should be the same.");
+			m_context << (u256(1) << (256 - typeOnStack.getNumBits())) << eth::Instruction::MUL;
+		}
+		else if (targetTypeCategory == Type::Category::Enum)
+			// just clean
+			appendTypeConversion(_typeOnStack, *_typeOnStack.getRealType(), true);
+		else
+		{
+			solAssert(targetTypeCategory == Type::Category::Integer || targetTypeCategory == Type::Category::Contract, "");
+			IntegerType addressType(0, IntegerType::Modifier::Address);
+			IntegerType const& targetType = targetTypeCategory == Type::Category::Integer
+											? dynamic_cast<IntegerType const&>(_targetType) : addressType;
+			if (stackTypeCategory == Type::Category::IntegerConstant)
+			{
+				IntegerConstantType const& constType = dynamic_cast<IntegerConstantType const&>(_typeOnStack);
+				// We know that the stack is clean, we only have to clean for a narrowing conversion
+				// where cleanup is forced.
+				if (targetType.getNumBits() < constType.getIntegerType()->getNumBits() && _cleanupNeeded)
+					appendHighBitsCleanup(targetType);
+			}
+			else
+			{
+				IntegerType const& typeOnStack = stackTypeCategory == Type::Category::Integer
+												? dynamic_cast<IntegerType const&>(_typeOnStack) : addressType;
+				// Widening: clean up according to source type width
+				// Non-widening and force: clean up according to target type bits
+				if (targetType.getNumBits() > typeOnStack.getNumBits())
+					appendHighBitsCleanup(typeOnStack);
+				else if (_cleanupNeeded)
+					appendHighBitsCleanup(targetType);
+			}
+		}
 	}
 	else if (_typeOnStack != _targetType)
 		// All other types should not be convertible to non-equal types.
@@ -586,181 +833,415 @@ void ExpressionCompiler::appendHighBitsCleanup(IntegerType const& _typeOnStack)
 
 void ExpressionCompiler::appendExternalFunctionCall(FunctionType const& _functionType,
 													vector<ASTPointer<Expression const>> const& _arguments,
-													FunctionCallOptions const& _options)
+													bool bare)
 {
-	solAssert(_arguments.size() == _functionType.getParameterTypes().size(), "");
+	solAssert(_functionType.takesArbitraryParameters() ||
+			  _arguments.size() == _functionType.getParameterTypes().size(), "");
+
+	// Assumed stack content here:
+	// <stack top>
+	// value [if _functionType.valueSet()]
+	// gas [if _functionType.gasSet()]
+	// function identifier [unless bare]
+	// contract address
+
+	unsigned gasValueSize = (_functionType.gasSet() ? 1 : 0) + (_functionType.valueSet() ? 1 : 0);
+
+	unsigned contractStackPos = m_context.currentToBaseStackOffset(1 + gasValueSize + (bare ? 0 : 1));
+	unsigned gasStackPos = m_context.currentToBaseStackOffset(gasValueSize);
+	unsigned valueStackPos = m_context.currentToBaseStackOffset(1);
 
-	unsigned dataOffset = _options.bare ? 0 : 1; // reserve one byte for the function index
-	for (unsigned i = 0; i < _arguments.size(); ++i)
-	{
-		_arguments[i]->accept(*this);
-		Type const& type = *_functionType.getParameterTypes()[i];
-		appendTypeConversion(*_arguments[i]->getType(), type);
-		unsigned const numBytes = _options.packDensely ? type.getCalldataEncodedSize() : 32;
-		if (numBytes == 0 || numBytes > 32)
-			BOOST_THROW_EXCEPTION(CompilerError()
-								  << errinfo_sourceLocation(_arguments[i]->getLocation())
-								  << errinfo_comment("Type " + type.toString() + " not yet supported."));
-		bool const leftAligned = type.getCategory() == Type::Category::STRING;
-		CompilerUtils(m_context).storeInMemory(dataOffset, numBytes, leftAligned);
-		dataOffset += numBytes;
-	}
 	//@todo only return the first return value for now
 	Type const* firstType = _functionType.getReturnParameterTypes().empty() ? nullptr :
 							_functionType.getReturnParameterTypes().front().get();
-	unsigned retSize = firstType ? firstType->getCalldataEncodedSize() : 0;
-	if (!_options.packDensely && retSize > 0)
-		retSize = 32;
-	// CALL arguments: outSize, outOff, inSize, inOff, value, addr, gas (stack top)
-	m_context << u256(retSize) << u256(0) << u256(dataOffset) << u256(0);
-	if (_options.obtainValue)
-		_options.obtainValue();
+	unsigned retSize = firstType ? CompilerUtils::getPaddedSize(firstType->getCalldataEncodedSize()) : 0;
+	m_context << u256(retSize) << u256(0);
+
+	if (bare)
+		m_context << u256(0);
+	else
+	{
+		// copy function identifier
+		m_context << eth::dupInstruction(gasValueSize + 3);
+		CompilerUtils(m_context).storeInMemory(0, IntegerType(CompilerUtils::dataStartOffset * 8));
+		m_context << u256(CompilerUtils::dataStartOffset);
+	}
+
+	// For bare call, activate "4 byte pad exception": If the first argument has exactly 4 bytes,
+	// do not pad it to 32 bytes.
+	appendArgumentsCopyToMemory(_arguments, _functionType.getParameterTypes(),
+								_functionType.padArguments(), bare);
+
+	// CALL arguments: outSize, outOff, inSize, (already present up to here)
+	// inOff, value, addr, gas (stack top)
+	m_context << u256(0);
+	if (_functionType.valueSet())
+		m_context << eth::dupInstruction(m_context.baseToCurrentStackOffset(valueStackPos));
 	else
 		m_context << u256(0);
-	_options.obtainAddress();
-	if (!_options.bare)
-		m_context << u256(0) << eth::Instruction::MSTORE8;
-	m_context << u256(25) << eth::Instruction::GAS << eth::Instruction::SUB
-			  << eth::Instruction::CALL
+	m_context << eth::dupInstruction(m_context.baseToCurrentStackOffset(contractStackPos));
+
+	if (_functionType.gasSet())
+		m_context << eth::dupInstruction(m_context.baseToCurrentStackOffset(gasStackPos));
+	else
+		// send all gas except for the 21 needed to execute "SUB" and "CALL"
+		m_context << u256(21) << eth::Instruction::GAS << eth::Instruction::SUB;
+	m_context << eth::Instruction::CALL
 			  << eth::Instruction::POP; // @todo do not ignore failure indicator
-	if (retSize > 0)
+	if (_functionType.valueSet())
+		m_context << eth::Instruction::POP;
+	if (_functionType.gasSet())
+		m_context << eth::Instruction::POP;
+	if (!bare)
+		m_context << eth::Instruction::POP;
+	m_context << eth::Instruction::POP; // pop contract address
+
+	if (firstType)
+		CompilerUtils(m_context).loadFromMemory(0, *firstType, false, true);
+}
+
+void ExpressionCompiler::appendArgumentsCopyToMemory(vector<ASTPointer<Expression const>> const& _arguments,
+													 TypePointers const& _types,
+													 bool _padToWordBoundaries,
+													 bool _padExceptionIfFourBytes)
+{
+	solAssert(_types.empty() || _types.size() == _arguments.size(), "");
+	for (size_t i = 0; i < _arguments.size(); ++i)
 	{
-		bool const leftAligned = firstType->getCategory() == Type::Category::STRING;
-		CompilerUtils(m_context).loadFromMemory(0, retSize, leftAligned);
+		_arguments[i]->accept(*this);
+		TypePointer const& expectedType = _types.empty() ? _arguments[i]->getType()->getRealType() : _types[i];
+		appendTypeConversion(*_arguments[i]->getType(), *expectedType, true);
+		bool pad = _padToWordBoundaries;
+		// Do not pad if the first argument has exactly four bytes
+		if (i == 0 && pad && _padExceptionIfFourBytes && expectedType->getCalldataEncodedSize() == 4)
+			pad = false;
+		appendTypeMoveToMemory(*expectedType, pad);
 	}
 }
 
-ExpressionCompiler::LValue::LValue(CompilerContext& _compilerContext, LValueType _type, Type const& _dataType,
-								   unsigned _baseStackOffset):
-	m_context(&_compilerContext), m_type(_type), m_baseStackOffset(_baseStackOffset),
-	m_stackSize(_dataType.getSizeOnStack())
+void ExpressionCompiler::appendTypeMoveToMemory(Type const& _type, bool _padToWordBoundaries)
+{
+	CompilerUtils(m_context).storeInMemoryDynamic(_type, _padToWordBoundaries);
+}
+
+void ExpressionCompiler::appendExpressionCopyToMemory(Type const& _expectedType, Expression const& _expression)
 {
+	_expression.accept(*this);
+	appendTypeConversion(*_expression.getType(), _expectedType, true);
+	appendTypeMoveToMemory(_expectedType);
 }
 
-void ExpressionCompiler::LValue::retrieveValue(Expression const& _expression, bool _remove) const
+void ExpressionCompiler::appendStateVariableAccessor(VariableDeclaration const& _varDecl)
+{
+	FunctionType accessorType(_varDecl);
+
+	unsigned length = 0;
+	TypePointers const& paramTypes = accessorType.getParameterTypes();
+	// move arguments to memory
+	for (TypePointer const& paramType: boost::adaptors::reverse(paramTypes))
+		length += CompilerUtils(m_context).storeInMemory(length, *paramType, true);
+
+	// retrieve the position of the variable
+	m_context << m_context.getStorageLocationOfVariable(_varDecl);
+	TypePointer returnType = _varDecl.getType();
+
+	for (TypePointer const& paramType: paramTypes)
+	{
+		// move offset to memory
+		CompilerUtils(m_context).storeInMemory(length);
+		unsigned argLen = CompilerUtils::getPaddedSize(paramType->getCalldataEncodedSize());
+		length -= argLen;
+		m_context << u256(argLen + 32) << u256(length) << eth::Instruction::SHA3;
+
+		returnType = dynamic_cast<MappingType const&>(*returnType).getValueType();
+	}
+
+	unsigned retSizeOnStack = 0;
+	solAssert(accessorType.getReturnParameterTypes().size() >= 1, "");
+	if (StructType const* structType = dynamic_cast<StructType const*>(returnType.get()))
+	{
+		auto const& names = accessorType.getReturnParameterNames();
+		auto const& types = accessorType.getReturnParameterTypes();
+		// struct
+		for (size_t i = 0; i < names.size(); ++i)
+		{
+			m_context << eth::Instruction::DUP1
+					  << structType->getStorageOffsetOfMember(names[i])
+					  << eth::Instruction::ADD;
+			m_currentLValue = LValue(m_context, LValue::LValueType::Storage, types[i]);
+			m_currentLValue.retrieveValue(Location(), true);
+			solAssert(types[i]->getSizeOnStack() == 1, "Returning struct elements with stack size != 1 not yet implemented.");
+			m_context << eth::Instruction::SWAP1;
+			retSizeOnStack += types[i]->getSizeOnStack();
+		}
+		m_context << eth::Instruction::POP;
+	}
+	else
+	{
+		// simple value
+		solAssert(accessorType.getReturnParameterTypes().size() == 1, "");
+		m_currentLValue = LValue(m_context, LValue::LValueType::Storage, returnType);
+		m_currentLValue.retrieveValue(Location(), true);
+		retSizeOnStack = returnType->getSizeOnStack();
+	}
+	solAssert(retSizeOnStack <= 15, "Stack too deep.");
+	m_context << eth::dupInstruction(retSizeOnStack + 1) << eth::Instruction::JUMP;
+}
+
+ExpressionCompiler::LValue::LValue(CompilerContext& _compilerContext, LValueType _type,
+								   TypePointer const& _dataType, unsigned _baseStackOffset):
+	m_context(&_compilerContext), m_type(_type), m_dataType(_dataType),
+	m_baseStackOffset(_baseStackOffset)
+{
+	//@todo change the type cast for arrays
+	solAssert(m_dataType->getStorageSize() <= numeric_limits<unsigned>::max(),
+			  "The storage size of " + m_dataType->toString() + " should fit in unsigned");
+	if (m_type == LValueType::Storage)
+		m_size = unsigned(m_dataType->getStorageSize());
+	else
+		m_size = unsigned(m_dataType->getSizeOnStack());
+}
+
+void ExpressionCompiler::LValue::fromIdentifier(Identifier const& _identifier, Declaration const& _declaration)
+{
+	if (m_context->isLocalVariable(&_declaration))
+	{
+		m_type = LValueType::Stack;
+		m_dataType = _identifier.getType();
+		m_size = m_dataType->getSizeOnStack();
+		m_baseStackOffset = m_context->getBaseStackOffsetOfVariable(_declaration);
+	}
+	else if (m_context->isStateVariable(&_declaration))
+	{
+		*m_context << m_context->getStorageLocationOfVariable(_declaration);
+		m_type = LValueType::Storage;
+		m_dataType = _identifier.getType();
+		solAssert(m_dataType->getStorageSize() <= numeric_limits<unsigned>::max(),
+				  "The storage size of " + m_dataType->toString() + " should fit in an unsigned");
+		m_size = unsigned(m_dataType->getStorageSize());	}
+	else
+		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_sourceLocation(_identifier.getLocation())
+													  << errinfo_comment("Identifier type not supported or identifier not found."));
+}
+
+void ExpressionCompiler::LValue::retrieveValue(Location const& _location, bool _remove) const
 {
 	switch (m_type)
 	{
-	case STACK:
+	case LValueType::Stack:
 	{
 		unsigned stackPos = m_context->baseToCurrentStackOffset(unsigned(m_baseStackOffset));
 		if (stackPos >= 15) //@todo correct this by fetching earlier or moving to memory
-			BOOST_THROW_EXCEPTION(CompilerError() << errinfo_sourceLocation(_expression.getLocation())
+			BOOST_THROW_EXCEPTION(CompilerError() << errinfo_sourceLocation(_location)
 												  << errinfo_comment("Stack too deep."));
-		for (unsigned i = 0; i < m_stackSize; ++i)
+		for (unsigned i = 0; i < m_size; ++i)
 			*m_context << eth::dupInstruction(stackPos + 1);
 		break;
 	}
-	case STORAGE:
-		if (!_expression.getType()->isValueType())
-			break; // no distinction between value and reference for non-value types
-		if (!_remove)
-			*m_context << eth::Instruction::DUP1;
-		if (m_stackSize == 1)
-			*m_context << eth::Instruction::SLOAD;
-		else
-			for (unsigned i = 0; i < m_stackSize; ++i)
-			{
-				*m_context << eth::Instruction::DUP1 << eth::Instruction::SLOAD << eth::Instruction::SWAP1;
-				if (i + 1 < m_stackSize)
-					 *m_context << u256(1) << eth::Instruction::ADD;
-				else
-					*m_context << eth::Instruction::POP;
-			}
+	case LValueType::Storage:
+		retrieveValueFromStorage(_remove);
 		break;
-	case MEMORY:
-		if (!_expression.getType()->isValueType())
+	case LValueType::Memory:
+		if (!m_dataType->isValueType())
 			break; // no distinction between value and reference for non-value types
-		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_sourceLocation(_expression.getLocation())
+		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_sourceLocation(_location)
 													  << errinfo_comment("Location type not yet implemented."));
 		break;
 	default:
-		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_sourceLocation(_expression.getLocation())
+		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_sourceLocation(_location)
 													  << errinfo_comment("Unsupported location type."));
 		break;
 	}
 }
 
-void ExpressionCompiler::LValue::storeValue(Expression const& _expression, bool _move) const
+void ExpressionCompiler::LValue::retrieveValueFromStorage(bool _remove) const
+{
+	if (!m_dataType->isValueType())
+		return; // no distinction between value and reference for non-value types
+	if (!_remove)
+		*m_context << eth::Instruction::DUP1;
+	if (m_size == 1)
+		*m_context << eth::Instruction::SLOAD;
+	else
+		for (unsigned i = 0; i < m_size; ++i)
+		{
+			*m_context << eth::Instruction::DUP1 << eth::Instruction::SLOAD << eth::Instruction::SWAP1;
+			if (i + 1 < m_size)
+				*m_context << u256(1) << eth::Instruction::ADD;
+			else
+				*m_context << eth::Instruction::POP;
+		}
+}
+
+void ExpressionCompiler::LValue::storeValue(Type const& _sourceType, Location const& _location, bool _move) const
 {
 	switch (m_type)
 	{
-	case STACK:
+	case LValueType::Stack:
 	{
-		unsigned stackDiff = m_context->baseToCurrentStackOffset(unsigned(m_baseStackOffset)) - m_stackSize + 1;
+		unsigned stackDiff = m_context->baseToCurrentStackOffset(unsigned(m_baseStackOffset)) - m_size + 1;
 		if (stackDiff > 16)
-			BOOST_THROW_EXCEPTION(CompilerError() << errinfo_sourceLocation(_expression.getLocation())
+			BOOST_THROW_EXCEPTION(CompilerError() << errinfo_sourceLocation(_location)
 												  << errinfo_comment("Stack too deep."));
 		else if (stackDiff > 0)
-			for (unsigned i = 0; i < m_stackSize; ++i)
+			for (unsigned i = 0; i < m_size; ++i)
 				*m_context << eth::swapInstruction(stackDiff) << eth::Instruction::POP;
 		if (!_move)
-			retrieveValue(_expression);
+			retrieveValue(_location);
 		break;
 	}
-	case LValue::STORAGE:
-		if (!_expression.getType()->isValueType())
-			break; // no distinction between value and reference for non-value types
-		// stack layout: value value ... value ref
-		if (!_move) // copy values
+	case LValueType::Storage:
+		// stack layout: value value ... value target_ref
+		if (m_dataType->isValueType())
 		{
-			if (m_stackSize + 1 > 16)
-				BOOST_THROW_EXCEPTION(CompilerError() << errinfo_sourceLocation(_expression.getLocation())
-													  << errinfo_comment("Stack too deep."));
-			for (unsigned i = 0; i < m_stackSize; ++i)
-				*m_context << eth::dupInstruction(m_stackSize + 1) << eth::Instruction::SWAP1;
+			if (!_move) // copy values
+			{
+				if (m_size + 1 > 16)
+					BOOST_THROW_EXCEPTION(CompilerError() << errinfo_sourceLocation(_location)
+														  << errinfo_comment("Stack too deep."));
+				for (unsigned i = 0; i < m_size; ++i)
+					*m_context << eth::dupInstruction(m_size + 1) << eth::Instruction::SWAP1;
+			}
+			if (m_size > 0) // store high index value first
+				*m_context << u256(m_size - 1) << eth::Instruction::ADD;
+			for (unsigned i = 0; i < m_size; ++i)
+			{
+				if (i + 1 >= m_size)
+					*m_context << eth::Instruction::SSTORE;
+				else
+					// stack here: value value ... value value (target_ref+offset)
+					*m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2
+							   << eth::Instruction::SSTORE
+							   << u256(1) << eth::Instruction::SWAP1 << eth::Instruction::SUB;
+			}
 		}
-		if (m_stackSize > 0) // store high index value first
-			*m_context << u256(m_stackSize - 1) << eth::Instruction::ADD;
-		for (unsigned i = 0; i < m_stackSize; ++i)
+		else
 		{
-			if (i + 1 >= m_stackSize)
-				*m_context << eth::Instruction::SSTORE;
+			solAssert(_sourceType.getCategory() == m_dataType->getCategory(), "");
+			if (m_dataType->getCategory() == Type::Category::ByteArray)
+			{
+				CompilerUtils(*m_context).copyByteArrayToStorage(
+							dynamic_cast<ByteArrayType const&>(*m_dataType),
+							dynamic_cast<ByteArrayType const&>(_sourceType));
+				if (_move)
+					*m_context << eth::Instruction::POP;
+			}
+			else if (m_dataType->getCategory() == Type::Category::Struct)
+			{
+				// stack layout: source_ref target_ref
+				auto const& structType = dynamic_cast<StructType const&>(*m_dataType);
+				solAssert(structType == _sourceType, "Struct assignment with conversion.");
+				for (auto const& member: structType.getMembers())
+				{
+					// assign each member that is not a mapping
+					TypePointer const& memberType = member.second;
+					if (memberType->getCategory() == Type::Category::Mapping)
+						continue;
+					*m_context << structType.getStorageOffsetOfMember(member.first)
+							   << eth::Instruction::DUP3 << eth::Instruction::DUP2
+							   << eth::Instruction::ADD;
+					// stack: source_ref target_ref member_offset source_member_ref
+					LValue rightHandSide(*m_context, LValueType::Storage, memberType);
+					rightHandSide.retrieveValue(_location, true);
+					// stack: source_ref target_ref member_offset source_value...
+					*m_context << eth::dupInstruction(2 + memberType->getSizeOnStack())
+							   << eth::dupInstruction(2 + memberType->getSizeOnStack())
+							   << eth::Instruction::ADD;
+					// stack: source_ref target_ref member_offset source_value... target_member_ref
+					LValue memberLValue(*m_context, LValueType::Storage, memberType);
+					memberLValue.storeValue(*memberType, _location, true);
+					*m_context << eth::Instruction::POP;
+				}
+				if (_move)
+					*m_context << eth::Instruction::POP;
+				else
+					*m_context << eth::Instruction::SWAP1;
+				*m_context << eth::Instruction::POP;
+			}
 			else
-				// v v ... v v r+x
-				*m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2
-						   << eth::Instruction::SSTORE
-						   << u256(1) << eth::Instruction::SWAP1 << eth::Instruction::SUB;
+				BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_sourceLocation(_location)
+															  << errinfo_comment("Invalid non-value type for assignment."));
 		}
 		break;
-	case LValue::MEMORY:
-		if (!_expression.getType()->isValueType())
+	case LValueType::Memory:
+		if (!m_dataType->isValueType())
 			break; // no distinction between value and reference for non-value types
-		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_sourceLocation(_expression.getLocation())
+		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_sourceLocation(_location)
 													  << errinfo_comment("Location type not yet implemented."));
 		break;
 	default:
-		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_sourceLocation(_expression.getLocation())
+		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_sourceLocation(_location)
 													  << errinfo_comment("Unsupported location type."));
 		break;
 	}
 }
 
-void ExpressionCompiler::LValue::retrieveValueIfLValueNotRequested(Expression const& _expression)
+void ExpressionCompiler::LValue::setToZero(Location const& _location) const
 {
-	if (!_expression.lvalueRequested())
+	switch (m_type)
 	{
-		retrieveValue(_expression, true);
-		reset();
+	case LValueType::Stack:
+	{
+		unsigned stackDiff = m_context->baseToCurrentStackOffset(unsigned(m_baseStackOffset));
+		if (stackDiff > 16)
+			BOOST_THROW_EXCEPTION(CompilerError() << errinfo_sourceLocation(_location)
+												  << errinfo_comment("Stack too deep."));
+		solAssert(stackDiff >= m_size - 1, "");
+		for (unsigned i = 0; i < m_size; ++i)
+			*m_context << u256(0) << eth::swapInstruction(stackDiff + 1 - i)
+						<< eth::Instruction::POP;
+		break;
+	}
+	case LValueType::Storage:
+		if (m_dataType->getCategory() == Type::Category::ByteArray)
+			CompilerUtils(*m_context).clearByteArray(dynamic_cast<ByteArrayType const&>(*m_dataType));
+		else if (m_dataType->getCategory() == Type::Category::Struct)
+		{
+			// stack layout: ref
+			auto const& structType = dynamic_cast<StructType const&>(*m_dataType);
+			for (auto const& member: structType.getMembers())
+			{
+				// zero each member that is not a mapping
+				TypePointer const& memberType = member.second;
+				if (memberType->getCategory() == Type::Category::Mapping)
+					continue;
+				*m_context << structType.getStorageOffsetOfMember(member.first)
+					<< eth::Instruction::DUP2 << eth::Instruction::ADD;
+				LValue memberValue(*m_context, LValueType::Storage, memberType);
+				memberValue.setToZero();
+			}
+			*m_context << eth::Instruction::POP;
+		}
+		else
+		{
+			if (m_size == 0)
+				*m_context << eth::Instruction::POP;
+			for (unsigned i = 0; i < m_size; ++i)
+				if (i + 1 >= m_size)
+					*m_context << u256(0) << eth::Instruction::SWAP1 << eth::Instruction::SSTORE;
+				else
+					*m_context << u256(0) << eth::Instruction::DUP2 << eth::Instruction::SSTORE
+								<< u256(1) << eth::Instruction::ADD;
+		}
+		break;
+	case LValueType::Memory:
+		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_sourceLocation(_location)
+													  << errinfo_comment("Location type not yet implemented."));
+		break;
+	default:
+		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_sourceLocation(_location)
+													  << errinfo_comment("Unsupported location type."));
+		break;
 	}
 }
 
-void ExpressionCompiler::LValue::fromIdentifier(Identifier const& _identifier, Declaration const& _declaration)
+void ExpressionCompiler::LValue::retrieveValueIfLValueNotRequested(Expression const& _expression)
 {
-	m_stackSize = _identifier.getType()->getSizeOnStack();
-	if (m_context->isLocalVariable(&_declaration))
-	{
-		m_type = STACK;
-		m_baseStackOffset = m_context->getBaseStackOffsetOfVariable(_declaration);
-	}
-	else if (m_context->isStateVariable(&_declaration))
+	if (!_expression.lvalueRequested())
 	{
-		m_type = STORAGE;
-		*m_context << m_context->getStorageLocationOfVariable(_declaration);
+		retrieveValue(_expression.getLocation(), true);
+		reset();
 	}
-	else
-		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_sourceLocation(_identifier.getLocation())
-													  << errinfo_comment("Identifier type not supported or identifier not found."));
 }
 
 }