text: /*
  	This file is part of solidity.
  
  	solidity is free software: you can redistribute it and/or modify
  	it under the terms of the GNU General Public License as published by
  	the Free Software Foundation, either version 3 of the License, or
  	(at your option) any later version.
  
  	solidity is distributed in the hope that it will be useful,
  	but WITHOUT ANY WARRANTY; without even the implied warranty of
  	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  	GNU General Public License for more details.
  
  	You should have received a copy of the GNU General Public License
  	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
  */
  /**
   * @author Christian <c@ethdev.com>
   * @date 2014
   * Solidity AST to EVM bytecode compiler for expressions.
   */
  
  #include <libsolidity/codegen/ExpressionCompiler.h>
  
  #include <libsolidity/ast/AST.h>
  #include <libsolidity/ast/TypeProvider.h>
  #include <libsolidity/codegen/CompilerContext.h>
  #include <libsolidity/codegen/CompilerUtils.h>
  #include <libsolidity/codegen/LValue.h>
  
  #include <libevmasm/GasMeter.h>
  #include <libsolutil/Common.h>
  #include <libsolutil/Keccak256.h>
  #include <libsolutil/Whiskers.h>
  
  #include <boost/algorithm/string/replace.hpp>
  #include <boost/range/adaptor/reversed.hpp>
  #include <numeric>
  #include <utility>
  
  using namespace std;
  using namespace solidity;
  using namespace solidity::evmasm;
  using namespace solidity::frontend;
  using namespace solidity::langutil;
  using namespace solidity::util;
  
  
  void ExpressionCompiler::compile(Expression const& _expression)
  {
  	_expression.accept(*this);
  }
  
  void ExpressionCompiler::appendStateVariableInitialization(VariableDeclaration const& _varDecl)
  {
  	if (!_varDecl.value())
  		return;
  	TypePointer type = _varDecl.value()->annotation().type;
  	solAssert(!!type, "Type information not available.");
  	CompilerContext::LocationSetter locationSetter(m_context, _varDecl);
  	_varDecl.value()->accept(*this);
  
  	if (_varDecl.annotation().type->dataStoredIn(DataLocation::Storage))
  	{
  		// reference type, only convert value to mobile type and do final conversion in storeValue.
  		auto mt = type->mobileType();
  		solAssert(mt, "");
  		utils().convertType(*type, *mt);
  		type = mt;
  	}
  	else
  	{
  		utils().convertType(*type, *_varDecl.annotation().type);
  		type = _varDecl.annotation().type;
  	}
  	StorageItem(m_context, _varDecl).storeValue(*type, _varDecl.location(), true);
  }
  
  void ExpressionCompiler::appendConstStateVariableAccessor(VariableDeclaration const& _varDecl)
  {
  	solAssert(_varDecl.isConstant(), "");
  	acceptAndConvert(*_varDecl.value(), *_varDecl.annotation().type);
  
  	// append return
  	m_context << dupInstruction(_varDecl.annotation().type->sizeOnStack() + 1);
  	m_context.appendJump(evmasm::AssemblyItem::JumpType::OutOfFunction);
  }
  
  void ExpressionCompiler::appendStateVariableAccessor(VariableDeclaration const& _varDecl)
  {
  	solAssert(!_varDecl.isConstant() && !_varDecl.immutable(), "");
  	CompilerContext::LocationSetter locationSetter(m_context, _varDecl);
  	FunctionType accessorType(_varDecl);
  
  	TypePointers paramTypes = accessorType.parameterTypes();
  	m_context.adjustStackOffset(1 + CompilerUtils::sizeOnStack(paramTypes));
  
  	// retrieve the position of the variable
  	auto const& location = m_context.storageLocationOfVariable(_varDecl);
  	m_context << location.first << u256(location.second);
  
  	TypePointer returnType = _varDecl.annotation().type;
  
  	for (size_t i = 0; i < paramTypes.size(); ++i)
  	{
  		if (auto mappingType = dynamic_cast<MappingType const*>(returnType))
  		{
  			solAssert(CompilerUtils::freeMemoryPointer >= 0x40, "");
  
  			// pop offset
  			m_context << Instruction::POP;
  			if (paramTypes[i]->isDynamicallySized())
  			{
  				solAssert(
  					dynamic_cast<ArrayType const&>(*paramTypes[i]).isByteArray(),
  					"Expected string or byte array for mapping key type"
  				);
  
  				// stack: <keys..> <slot position>
  
  				// copy key[i] to top.
  				utils().copyToStackTop(paramTypes.size() - i + 1, 1);
  
  				m_context.appendInlineAssembly(R"({
  					let key_len := mload(key_ptr)
  					// Temp. use the memory after the array data for the slot
  					// position
  					let post_data_ptr := add(key_ptr, add(key_len, 0x20))
  					let orig_data := mload(post_data_ptr)
  					mstore(post_data_ptr, slot_pos)
  					let hash := keccak256(add(key_ptr, 0x20), add(key_len, 0x20))
  					mstore(post_data_ptr, orig_data)
  					slot_pos := hash
  				})", {"slot_pos", "key_ptr"});
  
  				m_context << Instruction::POP;
  			}
  			else
  			{
  				solAssert(paramTypes[i]->isValueType(), "Expected value type for mapping key");
  
  				// move storage offset to memory.
  				utils().storeInMemory(32);
  
  				// move key to memory.
  				utils().copyToStackTop(paramTypes.size() - i, 1);
  				utils().storeInMemory(0);
  				m_context << u256(64) << u256(0);
  				m_context << Instruction::KECCAK256;
  			}
  
  			// push offset
  			m_context << u256(0);
  			returnType = mappingType->valueType();
  		}
  		else if (auto arrayType = dynamic_cast<ArrayType const*>(returnType))
  		{
  			// pop offset
  			m_context << Instruction::POP;
  			utils().copyToStackTop(paramTypes.size() - i + 1, 1);
  			ArrayUtils(m_context).accessIndex(*arrayType);
  			returnType = arrayType->baseType();
  		}
  		else
  			solAssert(false, "Index access is allowed only for \"mapping\" and \"array\" types.");
  	}
  	// remove index arguments.
  	if (paramTypes.size() == 1)
  		m_context << Instruction::SWAP2 << Instruction::POP << Instruction::SWAP1;
  	else if (paramTypes.size() >= 2)
  	{
  		m_context << swapInstruction(paramTypes.size());
  		m_context << Instruction::POP;
  		m_context << swapInstruction(paramTypes.size());
  		utils().popStackSlots(paramTypes.size() - 1);
  	}
  	unsigned retSizeOnStack = 0;
  	auto returnTypes = accessorType.returnParameterTypes();
  	solAssert(returnTypes.size() >= 1, "");
  	if (StructType const* structType = dynamic_cast<StructType const*>(returnType))
  	{
  		// remove offset
  		m_context << Instruction::POP;
  		auto const& names = accessorType.returnParameterNames();
  		// struct
  		for (size_t i = 0; i < names.size(); ++i)
  		{
  			if (returnTypes[i]->category() == Type::Category::Mapping)
  				continue;
  			if (auto arrayType = dynamic_cast<ArrayType const*>(returnTypes[i]))
  				if (!arrayType->isByteArray())
  					continue;
  			pair<u256, unsigned> const& offsets = structType->storageOffsetsOfMember(names[i]);
  			m_context << Instruction::DUP1 << u256(offsets.first) << Instruction::ADD << u256(offsets.second);
  			TypePointer memberType = structType->memberType(names[i]);
  			StorageItem(m_context, *memberType).retrieveValue(SourceLocation(), true);
  			utils().convertType(*memberType, *returnTypes[i]);
  			utils().moveToStackTop(returnTypes[i]->sizeOnStack());
  			retSizeOnStack += returnTypes[i]->sizeOnStack();
  		}
  		// remove slot
  		m_context << Instruction::POP;
  	}
  	else
  	{
  		// simple value or array
  		solAssert(returnTypes.size() == 1, "");
  		StorageItem(m_context, *returnType).retrieveValue(SourceLocation(), true);
  		utils().convertType(*returnType, *returnTypes.front());
  		retSizeOnStack = returnTypes.front()->sizeOnStack();
  	}
  	solAssert(retSizeOnStack == utils().sizeOnStack(returnTypes), "");
  	if (retSizeOnStack > 15)
  		BOOST_THROW_EXCEPTION(
  			CompilerError() <<
  			errinfo_sourceLocation(_varDecl.location()) <<
  			errinfo_comment("Stack too deep.")
  		);
  	m_context << dupInstruction(retSizeOnStack + 1);
  	m_context.appendJump(evmasm::AssemblyItem::JumpType::OutOfFunction);
  }
  
  bool ExpressionCompiler::visit(Conditional const& _condition)
  {
  	CompilerContext::LocationSetter locationSetter(m_context, _condition);
  	_condition.condition().accept(*this);
  	evmasm::AssemblyItem trueTag = m_context.appendConditionalJump();
  	acceptAndConvert(_condition.falseExpression(), *_condition.annotation().type);
  	evmasm::AssemblyItem endTag = m_context.appendJumpToNew();
  	m_context << trueTag;
  	int offset = _condition.annotation().type->sizeOnStack();
  	m_context.adjustStackOffset(-offset);
  	acceptAndConvert(_condition.trueExpression(), *_condition.annotation().type);
  	m_context << endTag;
  	return false;
  }
  
  bool ExpressionCompiler::visit(Assignment const& _assignment)
  {
  	CompilerContext::LocationSetter locationSetter(m_context, _assignment);
  	Token op = _assignment.assignmentOperator();
  	Token binOp = op == Token::Assign ? op : TokenTraits::AssignmentToBinaryOp(op);
  	Type const& leftType = *_assignment.leftHandSide().annotation().type;
  	if (leftType.category() == Type::Category::Tuple)
  	{
  		solAssert(*_assignment.annotation().type == TupleType(), "");
  		solAssert(op == Token::Assign, "");
  	}
  	else
  		solAssert(*_assignment.annotation().type == leftType, "");
  	bool cleanupNeeded = false;
  	if (op != Token::Assign)
  		cleanupNeeded = cleanupNeededForOp(leftType.category(), binOp);
  	_assignment.rightHandSide().accept(*this);
  	// Perform some conversion already. This will convert storage types to memory and literals
  	// to their actual type, but will not convert e.g. memory to storage.
  	TypePointer rightIntermediateType;
  	if (op != Token::Assign && TokenTraits::isShiftOp(binOp))
  		rightIntermediateType = _assignment.rightHandSide().annotation().type->mobileType();
  	else
  		rightIntermediateType = _assignment.rightHandSide().annotation().type->closestTemporaryType(
  			_assignment.leftHandSide().annotation().type
  		);
  	solAssert(rightIntermediateType, "");
  	utils().convertType(*_assignment.rightHandSide().annotation().type, *rightIntermediateType, cleanupNeeded);
  
  	_assignment.leftHandSide().accept(*this);
  	solAssert(!!m_currentLValue, "LValue not retrieved.");
  
  	if (op == Token::Assign)
  		m_currentLValue->storeValue(*rightIntermediateType, _assignment.location());
  	else  // compound assignment
  	{
  		solAssert(leftType.isValueType(), "Compound operators only available for value types.");
  		unsigned lvalueSize = m_currentLValue->sizeOnStack();
  		unsigned itemSize = _assignment.annotation().type->sizeOnStack();
  		if (lvalueSize > 0)
  		{
  			utils().copyToStackTop(lvalueSize + itemSize, itemSize);
  			utils().copyToStackTop(itemSize + lvalueSize, lvalueSize);
  			// value lvalue_ref value lvalue_ref
  		}
  		m_currentLValue->retrieveValue(_assignment.location(), true);
  		utils().convertType(leftType, leftType, cleanupNeeded);
  
  		if (TokenTraits::isShiftOp(binOp))
  			appendShiftOperatorCode(binOp, leftType, *rightIntermediateType);
  		else
  		{
  			solAssert(leftType == *rightIntermediateType, "");
  			appendOrdinaryBinaryOperatorCode(binOp, leftType);
  		}
  		if (lvalueSize > 0)
  		{
  			if (itemSize + lvalueSize > 16)
  				BOOST_THROW_EXCEPTION(
  					CompilerError() <<
  					errinfo_sourceLocation(_assignment.location()) <<
  					errinfo_comment("Stack too deep, try removing local variables.")
  				);
  			// value [lvalue_ref] updated_value
  			for (unsigned i = 0; i < itemSize; ++i)
  				m_context << swapInstruction(itemSize + lvalueSize) << Instruction::POP;
  		}
  		m_currentLValue->storeValue(*_assignment.annotation().type, _assignment.location());
  	}
  	m_currentLValue.reset();
  	return false;
  }
  
  bool ExpressionCompiler::visit(TupleExpression const& _tuple)
  {
  	if (_tuple.isInlineArray())
  	{
  		ArrayType const& arrayType = dynamic_cast<ArrayType const&>(*_tuple.annotation().type);
  
  		solAssert(!arrayType.isDynamicallySized(), "Cannot create dynamically sized inline array.");
  		utils().allocateMemory(max(u256(32u), arrayType.memoryDataSize()));
  		m_context << Instruction::DUP1;
  
  		for (auto const& component: _tuple.components())
  		{
  			acceptAndConvert(*component, *arrayType.baseType(), true);
  			utils().storeInMemoryDynamic(*arrayType.baseType(), true);
  		}
  
  		m_context << Instruction::POP;
  	}
  	else
  	{
  		vector<unique_ptr<LValue>> lvalues;
  		for (auto const& component: _tuple.components())
  			if (component)
  			{
  				component->accept(*this);
  				if (_tuple.annotation().lValueRequested)
  				{
  					solAssert(!!m_currentLValue, "");
  					lvalues.push_back(move(m_currentLValue));
  				}
  			}
  			else if (_tuple.annotation().lValueRequested)
  				lvalues.push_back(unique_ptr<LValue>());
  		if (_tuple.annotation().lValueRequested)
  		{
  			if (_tuple.components().size() == 1)
  				m_currentLValue = move(lvalues[0]);
  			else
  				m_currentLValue = make_unique<TupleObject>(m_context, move(lvalues));
  		}
  	}
  	return false;
  }
  
  bool ExpressionCompiler::visit(UnaryOperation const& _unaryOperation)
  {
  	CompilerContext::LocationSetter locationSetter(m_context, _unaryOperation);
  	if (_unaryOperation.annotation().type->category() == Type::Category::RationalNumber)
  	{
  		m_context << _unaryOperation.annotation().type->literalValue(nullptr);
  		return false;
  	}
  
  	_unaryOperation.subExpression().accept(*this);
  
  	switch (_unaryOperation.getOperator())
  	{
  	case Token::Not: // !
  		m_context << Instruction::ISZERO;
  		break;
  	case Token::BitNot: // ~
  		m_context << Instruction::NOT;
  		break;
  	case Token::Delete: // delete
  		solAssert(!!m_currentLValue, "LValue not retrieved.");
  		m_currentLValue->setToZero(_unaryOperation.location());
  		m_currentLValue.reset();
  		break;
  	case Token::Inc: // ++ (pre- or postfix)
  	case Token::Dec: // -- (pre- or postfix)
  		solAssert(!!m_currentLValue, "LValue not retrieved.");
  		solUnimplementedAssert(
  			_unaryOperation.annotation().type->category() != Type::Category::FixedPoint,
  			"Not yet implemented - FixedPointType."
  		);
  		m_currentLValue->retrieveValue(_unaryOperation.location());
  		if (!_unaryOperation.isPrefixOperation())
  		{
  			// store value for later
  			solUnimplementedAssert(_unaryOperation.annotation().type->sizeOnStack() == 1, "Stack size != 1 not implemented.");
  			m_context << Instruction::DUP1;
  			if (m_currentLValue->sizeOnStack() > 0)
  				for (unsigned i = 1 + m_currentLValue->sizeOnStack(); i > 0; --i)
  					m_context << swapInstruction(i);
  		}
  		m_context << u256(1);
  		if (_unaryOperation.getOperator() == Token::Inc)
  			m_context << Instruction::ADD;
  		else
  			m_context << Instruction::SWAP1 << Instruction::SUB;
  		// Stack for prefix: [ref...] (*ref)+-1
  		// Stack for postfix: *ref [ref...] (*ref)+-1
  		for (unsigned i = m_currentLValue->sizeOnStack(); i > 0; --i)
  			m_context << swapInstruction(i);
  		m_currentLValue->storeValue(
  			*_unaryOperation.annotation().type, _unaryOperation.location(),
  			!_unaryOperation.isPrefixOperation());
  		m_currentLValue.reset();
  		break;
  	case Token::Add: // +
  		// unary add, so basically no-op
  		break;
  	case Token::Sub: // -
  		m_context << u256(0) << Instruction::SUB;
  		break;
  	default:
  		solAssert(false, "Invalid unary operator: " + string(TokenTraits::toString(_unaryOperation.getOperator())));
  	}
  	return false;
  }
  
  bool ExpressionCompiler::visit(BinaryOperation const& _binaryOperation)
  {
  	CompilerContext::LocationSetter locationSetter(m_context, _binaryOperation);
  	Expression const& leftExpression = _binaryOperation.leftExpression();
  	Expression const& rightExpression = _binaryOperation.rightExpression();
  	solAssert(!!_binaryOperation.annotation().commonType, "");
  	TypePointer const& commonType = _binaryOperation.annotation().commonType;
  	Token const c_op = _binaryOperation.getOperator();
  
  	if (c_op == Token::And || c_op == Token::Or) // special case: short-circuiting
  		appendAndOrOperatorCode(_binaryOperation);
  	else if (commonType->category() == Type::Category::RationalNumber)
  		m_context << commonType->literalValue(nullptr);
  	else
  	{
  		bool cleanupNeeded = cleanupNeededForOp(commonType->category(), c_op);
  
  		TypePointer leftTargetType = commonType;
  		TypePointer rightTargetType = TokenTraits::isShiftOp(c_op) ? rightExpression.annotation().type->mobileType() : commonType;
  		solAssert(rightTargetType, "");
  
  		// for commutative operators, push the literal as late as possible to allow improved optimization
  		auto isLiteral = [](Expression const& _e)
  		{
  			return dynamic_cast<Literal const*>(&_e) || _e.annotation().type->category() == Type::Category::RationalNumber;
  		};
  		bool swap = m_optimiseOrderLiterals && TokenTraits::isCommutativeOp(c_op) && isLiteral(rightExpression) && !isLiteral(leftExpression);
  		if (swap)
  		{
  			acceptAndConvert(leftExpression, *leftTargetType, cleanupNeeded);
  			acceptAndConvert(rightExpression, *rightTargetType, cleanupNeeded);
  		}
  		else
  		{
  			acceptAndConvert(rightExpression, *rightTargetType, cleanupNeeded);
  			acceptAndConvert(leftExpression, *leftTargetType, cleanupNeeded);
  		}
  		if (TokenTraits::isShiftOp(c_op))
  			// shift only cares about the signedness of both sides
  			appendShiftOperatorCode(c_op, *leftTargetType, *rightTargetType);
  		else if (TokenTraits::isCompareOp(c_op))
  			appendCompareOperatorCode(c_op, *commonType);
  		else
  			appendOrdinaryBinaryOperatorCode(c_op, *commonType);
  	}
  
  	// do not visit the child nodes, we already did that explicitly
  	return false;
  }
  
  bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
  {
  	CompilerContext::LocationSetter locationSetter(m_context, _functionCall);
  	if (_functionCall.annotation().kind == FunctionCallKind::TypeConversion)
  	{
  		solAssert(_functionCall.arguments().size() == 1, "");
  		solAssert(_functionCall.names().empty(), "");
  		auto const& expression = *_functionCall.arguments().front();
  		auto const& targetType = *_functionCall.annotation().type;
  		if (auto const* typeType = dynamic_cast<TypeType const*>(expression.annotation().type))
  			if (auto const* addressType = dynamic_cast<AddressType const*>(&targetType))
  			{
  				auto const* contractType = dynamic_cast<ContractType const*>(typeType->actualType());
  				solAssert(
  					contractType &&
  					contractType->contractDefinition().isLibrary() &&
  					addressType->stateMutability() == StateMutability::NonPayable,
  					""
  				);
  				m_context.appendLibraryAddress(contractType->contractDefinition().fullyQualifiedName());
  				return false;
  			}
  		acceptAndConvert(expression, targetType);
  		return false;
  	}
  
  	FunctionTypePointer functionType;
  	if (_functionCall.annotation().kind == FunctionCallKind::StructConstructorCall)
  	{
  		auto const& type = dynamic_cast<TypeType const&>(*_functionCall.expression().annotation().type);
  		auto const& structType = dynamic_cast<StructType const&>(*type.actualType());
  		functionType = structType.constructorType();
  	}
  	else
  		functionType = dynamic_cast<FunctionType const*>(_functionCall.expression().annotation().type);
  
  	TypePointers parameterTypes = functionType->parameterTypes();
  	vector<ASTPointer<Expression const>> const& callArguments = _functionCall.arguments();
  	vector<ASTPointer<ASTString>> const& callArgumentNames = _functionCall.names();
  	if (!functionType->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: functionType->parameterNames())
  		{
  			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, "");
  		}
  
  	if (_functionCall.annotation().kind == FunctionCallKind::StructConstructorCall)
  	{
  		TypeType const& type = dynamic_cast<TypeType const&>(*_functionCall.expression().annotation().type);
  		auto const& structType = dynamic_cast<StructType const&>(*type.actualType());
  
  		utils().allocateMemory(max(u256(32u), structType.memoryDataSize()));
  		m_context << Instruction::DUP1;
  
  		for (unsigned i = 0; i < arguments.size(); ++i)
  		{
  			acceptAndConvert(*arguments[i], *functionType->parameterTypes()[i]);
  			utils().storeInMemoryDynamic(*functionType->parameterTypes()[i]);
  		}
  		m_context << Instruction::POP;
  	}
  	else
  	{
  		FunctionType const& function = *functionType;
  		if (function.bound())
  			// Only delegatecall and internal functions can be bound, this might be lifted later.
  			solAssert(function.kind() == FunctionType::Kind::DelegateCall || function.kind() == FunctionType::Kind::Internal, "");
  		switch (function.kind())
  		{
  		case FunctionType::Kind::Declaration:
  			solAssert(false, "Attempted to generate code for calling a function definition.");
  			break;
  		case FunctionType::Kind::Internal:
  		{
  			// Calling convention: Caller pushes return address and arguments
  			// Callee removes them and pushes return values
  
  			evmasm::AssemblyItem returnLabel = m_context.pushNewTag();
  			for (unsigned i = 0; i < arguments.size(); ++i)
  				acceptAndConvert(*arguments[i], *function.parameterTypes()[i]);
  
  			{
  				bool shortcutTaken = false;
  				if (auto identifier = dynamic_cast<Identifier const*>(&_functionCall.expression()))
  				{
  					solAssert(!function.bound(), "");
  					if (auto functionDef = dynamic_cast<FunctionDefinition const*>(identifier->annotation().referencedDeclaration))
  					{
  						// Do not directly visit the identifier, because this way, we can avoid
  						// the runtime entry label to be created at the creation time context.
  						CompilerContext::LocationSetter locationSetter2(m_context, *identifier);
  						utils().pushCombinedFunctionEntryLabel(m_context.resolveVirtualFunction(*functionDef), false);
  						shortcutTaken = true;
  					}
  				}
  
  				if (!shortcutTaken)
  					_functionCall.expression().accept(*this);
  			}
  
  			unsigned parameterSize = CompilerUtils::sizeOnStack(function.parameterTypes());
  			if (function.bound())
  			{
  				// stack: arg2, ..., argn, label, arg1
  				unsigned depth = parameterSize + 1;
  				utils().moveIntoStack(depth, function.selfType()->sizeOnStack());
  				parameterSize += function.selfType()->sizeOnStack();
  			}
  
  			if (m_context.runtimeContext())
  				// We have a runtime context, so we need the creation part.
  				utils().rightShiftNumberOnStack(32);
  			else
  				// Extract the runtime part.
  				m_context << ((u256(1) << 32) - 1) << Instruction::AND;
  
  			m_context.appendJump(evmasm::AssemblyItem::JumpType::IntoFunction);
  			m_context << returnLabel;
  
  			unsigned returnParametersSize = CompilerUtils::sizeOnStack(function.returnParameterTypes());
  			// callee adds return parameters, but removes arguments and return label
  			m_context.adjustStackOffset(returnParametersSize - parameterSize - 1);
  			break;
  		}
  		case FunctionType::Kind::BareCall:
  		case FunctionType::Kind::BareDelegateCall:
  		case FunctionType::Kind::BareStaticCall:
  			solAssert(!_functionCall.annotation().tryCall, "");
  			[[fallthrough]];
  		case FunctionType::Kind::External:
  		case FunctionType::Kind::DelegateCall:
  			_functionCall.expression().accept(*this);
  			appendExternalFunctionCall(function, arguments, _functionCall.annotation().tryCall);
  			break;
  		case FunctionType::Kind::BareCallCode:
  			solAssert(false, "Callcode has been removed.");
  		case FunctionType::Kind::Creation:
  		{
  			_functionCall.expression().accept(*this);
  			// Stack: [salt], [value]
  
  			solAssert(!function.gasSet(), "Gas limit set for contract creation.");
  			solAssert(function.returnParameterTypes().size() == 1, "");
  			TypePointers argumentTypes;
  			for (auto const& arg: arguments)
  			{
  				arg->accept(*this);
  				argumentTypes.push_back(arg->annotation().type);
  			}
  			ContractDefinition const* contract =
  				&dynamic_cast<ContractType const&>(*function.returnParameterTypes().front()).contractDefinition();
  			utils().fetchFreeMemoryPointer();
  			utils().copyContractCodeToMemory(*contract, true);
  			utils().abiEncode(argumentTypes, function.parameterTypes());
  			// now on stack: [salt], [value], memory_end_ptr
  			// need: [salt], size, offset, value
  
  			if (function.saltSet())
  			{
  				m_context << dupInstruction(2 + (function.valueSet() ? 1 : 0));
  				m_context << Instruction::SWAP1;
  			}
  
  			// now: [salt], [value], [salt], memory_end_ptr
  			utils().toSizeAfterFreeMemoryPointer();
  
  			// now: [salt], [value], [salt], size, offset
  			if (function.valueSet())
  				m_context << dupInstruction(3 + (function.saltSet() ? 1 : 0));
  			else
  				m_context << u256(0);
  
  			// now: [salt], [value], [salt], size, offset, value
  			if (function.saltSet())
  				m_context << Instruction::CREATE2;
  			else
  				m_context << Instruction::CREATE;
  
  			// now: [salt], [value], address
  
  			if (function.valueSet())
  				m_context << swapInstruction(1) << Instruction::POP;
  			if (function.saltSet())
  				m_context << swapInstruction(1) << Instruction::POP;
  
  			// Check if zero (reverted)
  			m_context << Instruction::DUP1 << Instruction::ISZERO;
  			if (_functionCall.annotation().tryCall)
  			{
  				// If this is a try call, return "<address> 1" in the success case and
  				// "0" in the error case.
  				AssemblyItem errorCase = m_context.appendConditionalJump();
  				m_context << u256(1);
  				m_context << errorCase;
  			}
  			else
  				m_context.appendConditionalRevert(true);
  			break;
  		}
  		case FunctionType::Kind::SetGas:
  		{
  			// stack layout: contract_address function_id [gas] [value]
  			_functionCall.expression().accept(*this);
  
  			acceptAndConvert(*arguments.front(), *TypeProvider::uint256(), 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 << swapInstruction(stackDepth);
  			if (function.gasSet())
  				m_context << Instruction::POP;
  			break;
  		}
  		case FunctionType::Kind::SetValue:
  			// stack layout: contract_address function_id [gas] [value]
  			_functionCall.expression().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 << Instruction::POP;
  			arguments.front()->accept(*this);
  			break;
  		case FunctionType::Kind::Send:
  		case FunctionType::Kind::Transfer:
  			_functionCall.expression().accept(*this);
  			// Provide the gas stipend manually at first because we may send zero ether.
  			// Will be zeroed if we send more than zero ether.
  			m_context << u256(evmasm::GasCosts::callStipend);
  			acceptAndConvert(*arguments.front(), *function.parameterTypes().front(), true);
  			// gas <- gas * !value
  			m_context << Instruction::SWAP1 << Instruction::DUP2;
  			m_context << Instruction::ISZERO << Instruction::MUL << Instruction::SWAP1;
  			appendExternalFunctionCall(
  				FunctionType(
  					TypePointers{},
  					TypePointers{},
  					strings(),
  					strings(),
  					FunctionType::Kind::BareCall,
  					false,
  					StateMutability::NonPayable,
  					nullptr,
  					true,
  					true
  				),
  				{},
  				false
  			);
  			if (function.kind() == FunctionType::Kind::Transfer)
  			{
  				// Check if zero (out of stack or not enough balance).
  				m_context << Instruction::ISZERO;
  				// Revert message bubbles up.
  				m_context.appendConditionalRevert(true);
  			}
  			break;
  		case FunctionType::Kind::Selfdestruct:
  			acceptAndConvert(*arguments.front(), *function.parameterTypes().front(), true);
  			m_context << Instruction::SELFDESTRUCT;
  			break;
  		case FunctionType::Kind::Revert:
  		{
  			if (arguments.empty())
  				m_context.appendRevert();
  			else
  			{
  				// function-sel(Error(string)) + encoding
  				solAssert(arguments.size() == 1, "");
  				solAssert(function.parameterTypes().size() == 1, "");
  				if (m_context.revertStrings() == RevertStrings::Strip)
  				{
  					if (!arguments.front()->annotation().isPure)
  					{
  						arguments.front()->accept(*this);
  						utils().popStackElement(*arguments.front()->annotation().type);
  					}
  					m_context.appendRevert();
  				}
  				else
  				{
  					arguments.front()->accept(*this);
  					utils().revertWithStringData(*arguments.front()->annotation().type);
  				}
  			}
  			break;
  		}
  		case FunctionType::Kind::KECCAK256:
  		{
  			solAssert(arguments.size() == 1, "");
  			solAssert(!function.padArguments(), "");
  			TypePointer const& argType = arguments.front()->annotation().type;
  			solAssert(argType, "");
  			arguments.front()->accept(*this);
  			// Optimization: If type is bytes or string, then do not encode,
  			// but directly compute keccak256 on memory.
  			if (*argType == *TypeProvider::bytesMemory() || *argType == *TypeProvider::stringMemory())
  			{
  				ArrayUtils(m_context).retrieveLength(*TypeProvider::bytesMemory());
  				m_context << Instruction::SWAP1 << u256(0x20) << Instruction::ADD;
  			}
  			else
  			{
  				utils().fetchFreeMemoryPointer();
  				utils().packedEncode({argType}, TypePointers());
  				utils().toSizeAfterFreeMemoryPointer();
  			}
  			m_context << Instruction::KECCAK256;
  			break;
  		}
  		case FunctionType::Kind::Log0:
  		case FunctionType::Kind::Log1:
  		case FunctionType::Kind::Log2:
  		case FunctionType::Kind::Log3:
  		case FunctionType::Kind::Log4:
  		{
  			unsigned logNumber = int(function.kind()) - int(FunctionType::Kind::Log0);
  			for (unsigned arg = logNumber; arg > 0; --arg)
  				acceptAndConvert(*arguments[arg], *function.parameterTypes()[arg], true);
  			arguments.front()->accept(*this);
  			utils().fetchFreeMemoryPointer();
  			solAssert(function.parameterTypes().front()->isValueType(), "");
  			utils().packedEncode(
  				{arguments.front()->annotation().type},
  				{function.parameterTypes().front()}
  			);
  			utils().toSizeAfterFreeMemoryPointer();
  			m_context << logInstruction(logNumber);
  			break;
  		}
  		case FunctionType::Kind::Event:
  		{
  			_functionCall.expression().accept(*this);
  			auto const& event = dynamic_cast<EventDefinition const&>(function.declaration());
  			unsigned numIndexed = 0;
  			TypePointers paramTypes = function.parameterTypes();
  			// All indexed arguments go to the stack
  			for (unsigned arg = arguments.size(); arg > 0; --arg)
  				if (event.parameters()[arg - 1]->isIndexed())
  				{
  					++numIndexed;
  					arguments[arg - 1]->accept(*this);
  					if (auto const& referenceType = dynamic_cast<ReferenceType const*>(paramTypes[arg - 1]))
  					{
  						utils().fetchFreeMemoryPointer();
  						utils().packedEncode(
  							{arguments[arg - 1]->annotation().type},
  							{referenceType}
  						);
  						utils().toSizeAfterFreeMemoryPointer();
  						m_context << Instruction::KECCAK256;
  					}
  					else
  					{
  						solAssert(paramTypes[arg - 1]->isValueType(), "");
  						utils().convertType(
  							*arguments[arg - 1]->annotation().type,
  							*paramTypes[arg - 1],
  							true
  						);
  					}
  				}
  			if (!event.isAnonymous())
  			{
  				m_context << u256(h256::Arith(keccak256(function.externalSignature())));
  				++numIndexed;
  			}
  			solAssert(numIndexed <= 4, "Too many indexed arguments.");
  			// Copy all non-indexed arguments to memory (data)
  			// Memory position is only a hack and should be removed once we have free memory pointer.
  			TypePointers nonIndexedArgTypes;
  			TypePointers nonIndexedParamTypes;
  			for (unsigned arg = 0; arg < arguments.size(); ++arg)
  				if (!event.parameters()[arg]->isIndexed())
  				{
  					arguments[arg]->accept(*this);
  					nonIndexedArgTypes.push_back(arguments[arg]->annotation().type);
  					nonIndexedParamTypes.push_back(paramTypes[arg]);
  				}
  			utils().fetchFreeMemoryPointer();
  			utils().abiEncode(nonIndexedArgTypes, nonIndexedParamTypes);
  			// need: topic1 ... topicn memsize memstart
  			utils().toSizeAfterFreeMemoryPointer();
  			m_context << logInstruction(numIndexed);
  			break;
  		}
  		case FunctionType::Kind::BlockHash:
  		{
  			acceptAndConvert(*arguments[0], *function.parameterTypes()[0], true);
  			m_context << Instruction::BLOCKHASH;
  			break;
  		}
  		case FunctionType::Kind::AddMod:
  		case FunctionType::Kind::MulMod:
  		{
  			acceptAndConvert(*arguments[2], *TypeProvider::uint256());
  			m_context << Instruction::DUP1 << Instruction::ISZERO;
  			m_context.appendConditionalInvalid();
  			for (unsigned i = 1; i < 3; i ++)
  				acceptAndConvert(*arguments[2 - i], *TypeProvider::uint256());
  			if (function.kind() == FunctionType::Kind::AddMod)
  				m_context << Instruction::ADDMOD;
  			else
  				m_context << Instruction::MULMOD;
  			break;
  		}
  		case FunctionType::Kind::ECRecover:
  		case FunctionType::Kind::SHA256:
  		case FunctionType::Kind::RIPEMD160:
  		{
  			_functionCall.expression().accept(*this);
  			static map<FunctionType::Kind, u256> const contractAddresses{
  				{FunctionType::Kind::ECRecover, 1},
  				{FunctionType::Kind::SHA256, 2},
  				{FunctionType::Kind::RIPEMD160, 3}
  			};
  			m_context << contractAddresses.at(function.kind());
  			for (unsigned i = function.sizeOnStack(); i > 0; --i)
  				m_context << swapInstruction(i);
  			solAssert(!_functionCall.annotation().tryCall, "");
  			appendExternalFunctionCall(function, arguments, false);
  			break;
  		}
  		case FunctionType::Kind::ByteArrayPush:
  		case FunctionType::Kind::ArrayPush:
  		{
  			_functionCall.expression().accept(*this);
  
  			if (function.parameterTypes().size() == 0)
  			{
  				auto paramType = function.returnParameterTypes().at(0);
  				solAssert(paramType, "");
  
  				ArrayType const* arrayType =
  					function.kind() == FunctionType::Kind::ArrayPush ?
  					TypeProvider::array(DataLocation::Storage, paramType) :
  					TypeProvider::bytesStorage();
  
  				// stack: ArrayReference
  				m_context << u256(1) << Instruction::DUP2;
  				ArrayUtils(m_context).incrementDynamicArraySize(*arrayType);
  				// stack: ArrayReference 1 newLength
  				m_context << Instruction::SUB;
  				// stack: ArrayReference (newLength-1)
  				ArrayUtils(m_context).accessIndex(*arrayType, false);
  
  				if (arrayType->isByteArray())
  					setLValue<StorageByteArrayElement>(_functionCall);
  				else
  					setLValueToStorageItem(_functionCall);
  			}
  			else
  			{
  				solAssert(function.parameterTypes().size() == 1, "");
  				solAssert(!!function.parameterTypes()[0], "");
  				TypePointer paramType = function.parameterTypes()[0];
  				ArrayType const* arrayType =
  					function.kind() == FunctionType::Kind::ArrayPush ?
  					TypeProvider::array(DataLocation::Storage, paramType) :
  					TypeProvider::bytesStorage();
  
  				// stack: ArrayReference
  				arguments[0]->accept(*this);
  				TypePointer const& argType = arguments[0]->annotation().type;
  				// stack: ArrayReference argValue
  				utils().moveToStackTop(argType->sizeOnStack(), 1);
  				// stack: argValue ArrayReference
  				m_context << Instruction::DUP1;
  				ArrayUtils(m_context).incrementDynamicArraySize(*arrayType);
  				// stack: argValue ArrayReference newLength
  				m_context << u256(1) << Instruction::SWAP1 << Instruction::SUB;
  				// stack: argValue ArrayReference (newLength-1)
  				ArrayUtils(m_context).accessIndex(*arrayType, false);
  				// stack: argValue storageSlot slotOffset
  				utils().moveToStackTop(2, argType->sizeOnStack());
  				// stack: storageSlot slotOffset argValue
  				TypePointer type = arguments[0]->annotation().type->closestTemporaryType(arrayType->baseType());
  				solAssert(type, "");
  				utils().convertType(*argType, *type);
  				utils().moveToStackTop(1 + type->sizeOnStack());
  				utils().moveToStackTop(1 + type->sizeOnStack());
  				// stack: argValue storageSlot slotOffset
  				if (function.kind() == FunctionType::Kind::ArrayPush)
  					StorageItem(m_context, *paramType).storeValue(*type, _functionCall.location(), true);
  				else
  					StorageByteArrayElement(m_context).storeValue(*type, _functionCall.location(), true);
  			}
  			break;
  		}
  		case FunctionType::Kind::ArrayPop:
  		{
  			_functionCall.expression().accept(*this);
  			solAssert(function.parameterTypes().empty(), "");
  
  			ArrayType const& arrayType = dynamic_cast<ArrayType const&>(
  				*dynamic_cast<MemberAccess const&>(_functionCall.expression()).expression().annotation().type
  			);
  			solAssert(arrayType.dataStoredIn(DataLocation::Storage), "");
  
  			ArrayUtils(m_context).popStorageArrayElement(arrayType);
  			break;
  		}
  		case FunctionType::Kind::ObjectCreation:
  		{
  			ArrayType const& arrayType = dynamic_cast<ArrayType const&>(*_functionCall.annotation().type);
  			_functionCall.expression().accept(*this);
  			solAssert(arguments.size() == 1, "");
  
  			// Fetch requested length.
  			acceptAndConvert(*arguments[0], *TypeProvider::uint256());
  
  			// Stack: requested_length
  			utils().fetchFreeMemoryPointer();
  
  			// Stack: requested_length memptr
  			m_context << Instruction::SWAP1;
  			// Stack: memptr requested_length
  			// store length
  			m_context << Instruction::DUP1 << Instruction::DUP3 << Instruction::MSTORE;
  			// Stack: memptr requested_length
  			// update free memory pointer
  			m_context << Instruction::DUP1;
  			// Stack: memptr requested_length requested_length
  			if (arrayType.isByteArray())
  				// Round up to multiple of 32
  				m_context << u256(31) << Instruction::ADD << u256(31) << Instruction::NOT << Instruction::AND;
  			else
  				m_context << arrayType.baseType()->memoryHeadSize() << Instruction::MUL;
  			// stacK: memptr requested_length data_size
  			m_context << u256(32) << Instruction::ADD;
  			m_context << Instruction::DUP3 << Instruction::ADD;
  			utils().storeFreeMemoryPointer();
  			// Stack: memptr requested_length
  
  			// Check if length is zero
  			m_context << Instruction::DUP1 << Instruction::ISZERO;
  			auto skipInit = m_context.appendConditionalJump();
  			// Always initialize because the free memory pointer might point at
  			// a dirty memory area.
  			m_context << Instruction::DUP2 << u256(32) << Instruction::ADD;
  			utils().zeroInitialiseMemoryArray(arrayType);
  			m_context << skipInit;
  			m_context << Instruction::POP;
  			break;
  		}
  		case FunctionType::Kind::Assert:
  		case FunctionType::Kind::Require:
  		{
  			acceptAndConvert(*arguments.front(), *function.parameterTypes().front(), false);
  
  			bool haveReasonString = arguments.size() > 1 && m_context.revertStrings() != RevertStrings::Strip;
  
  			if (arguments.size() > 1)
  			{
  				// Users probably expect the second argument to be evaluated
  				// even if the condition is false, as would be the case for an actual
  				// function call.
  				solAssert(arguments.size() == 2, "");
  				solAssert(function.kind() == FunctionType::Kind::Require, "");
  				if (m_context.revertStrings() == RevertStrings::Strip)
  				{
  					if (!arguments.at(1)->annotation().isPure)
  					{
  						arguments.at(1)->accept(*this);
  						utils().popStackElement(*arguments.at(1)->annotation().type);
  					}
  				}
  				else
  				{
  					arguments.at(1)->accept(*this);
  					utils().moveIntoStack(1, arguments.at(1)->annotation().type->sizeOnStack());
  				}
  			}
  			// Stack: <error string (unconverted)> <condition>
  			// jump if condition was met
  			m_context << Instruction::ISZERO << Instruction::ISZERO;
  			auto success = m_context.appendConditionalJump();
  			if (function.kind() == FunctionType::Kind::Assert)
  				// condition was not met, flag an error
  				m_context.appendInvalid();
  			else if (haveReasonString)
  			{
  				utils().revertWithStringData(*arguments.at(1)->annotation().type);
  				// Here, the argument is consumed, but in the other branch, it is still there.
  				m_context.adjustStackOffset(arguments.at(1)->annotation().type->sizeOnStack());
  			}
  			else
  				m_context.appendRevert();
  			// the success branch
  			m_context << success;
  			if (haveReasonString)
  				utils().popStackElement(*arguments.at(1)->annotation().type);
  			break;
  		}
  		case FunctionType::Kind::ABIEncode:
  		case FunctionType::Kind::ABIEncodePacked:
  		case FunctionType::Kind::ABIEncodeWithSelector:
  		case FunctionType::Kind::ABIEncodeWithSignature:
  		{
  			bool const isPacked = function.kind() == FunctionType::Kind::ABIEncodePacked;
  			bool const hasSelectorOrSignature =
  				function.kind() == FunctionType::Kind::ABIEncodeWithSelector ||
  				function.kind() == FunctionType::Kind::ABIEncodeWithSignature;
  
  			TypePointers argumentTypes;
  			TypePointers targetTypes;
  			for (unsigned i = 0; i < arguments.size(); ++i)
  			{
  				arguments[i]->accept(*this);
  				// Do not keep the selector as part of the ABI encoded args
  				if (!hasSelectorOrSignature || i > 0)
  					argumentTypes.push_back(arguments[i]->annotation().type);
  			}
  			utils().fetchFreeMemoryPointer();
  			// stack now: [<selector>] <arg1> .. <argN> <free_mem>
  
  			// adjust by 32(+4) bytes to accommodate the length(+selector)
  			m_context << u256(32 + (hasSelectorOrSignature ? 4 : 0)) << Instruction::ADD;
  			// stack now: [<selector>] <arg1> .. <argN> <data_encoding_area_start>
  
  			if (isPacked)
  			{
  				solAssert(!function.padArguments(), "");
  				utils().packedEncode(argumentTypes, TypePointers());
  			}
  			else
  			{
  				solAssert(function.padArguments(), "");
  				utils().abiEncode(argumentTypes, TypePointers());
  			}
  			utils().fetchFreeMemoryPointer();
  			// stack: [<selector>] <data_encoding_area_end> <bytes_memory_ptr>
  
  			// size is end minus start minus length slot
  			m_context.appendInlineAssembly(R"({
  				mstore(mem_ptr, sub(sub(mem_end, mem_ptr), 0x20))
  			})", {"mem_end", "mem_ptr"});
  			m_context << Instruction::SWAP1;
  			utils().storeFreeMemoryPointer();
  			// stack: [<selector>] <memory ptr>
  
  			if (hasSelectorOrSignature)
  			{
  				// stack: <selector> <memory pointer>
  				solAssert(arguments.size() >= 1, "");
  				TypePointer const& selectorType = arguments[0]->annotation().type;
  				utils().moveIntoStack(selectorType->sizeOnStack());
  				TypePointer dataOnStack = selectorType;
  				// stack: <memory pointer> <selector>
  				if (function.kind() == FunctionType::Kind::ABIEncodeWithSignature)
  				{
  					// hash the signature
  					if (auto const* stringType = dynamic_cast<StringLiteralType const*>(selectorType))
  					{
  						FixedHash<4> hash(keccak256(stringType->value()));
  						m_context << (u256(FixedHash<4>::Arith(hash)) << (256 - 32));
  						dataOnStack = TypeProvider::fixedBytes(4);
  					}
  					else
  					{
  						utils().fetchFreeMemoryPointer();
  						// stack: <memory pointer> <selector> <free mem ptr>
  						utils().packedEncode(TypePointers{selectorType}, TypePointers());
  						utils().toSizeAfterFreeMemoryPointer();
  						m_context << Instruction::KECCAK256;
  						// stack: <memory pointer> <hash>
  
  						dataOnStack = TypeProvider::fixedBytes(32);
  					}
  				}
  				else
  				{
  					solAssert(function.kind() == FunctionType::Kind::ABIEncodeWithSelector, "");
  				}
  
  				utils().convertType(*dataOnStack, FixedBytesType(4), true);
  
  				// stack: <memory pointer> <selector>
  
  				// load current memory, mask and combine the selector
  				string mask = formatNumber((u256(-1) >> 32));
  				m_context.appendInlineAssembly(R"({
  					let data_start := add(mem_ptr, 0x20)
  					let data := mload(data_start)
  					let mask := )" + mask + R"(
  					mstore(data_start, or(and(data, mask), selector))
  				})", {"mem_ptr", "selector"});
  				m_context << Instruction::POP;
  			}
  
  			// stack now: <memory pointer>
  			break;
  		}
  		case FunctionType::Kind::ABIDecode:
  		{
  			arguments.front()->accept(*this);
  			TypePointer firstArgType = arguments.front()->annotation().type;
  			TypePointers targetTypes;
  			if (TupleType const* targetTupleType = dynamic_cast<TupleType const*>(_functionCall.annotation().type))
  				targetTypes = targetTupleType->components();
  			else
  				targetTypes = TypePointers{_functionCall.annotation().type};
  			if (
  				auto referenceType = dynamic_cast<ReferenceType const*>(firstArgType);
  				referenceType && referenceType->dataStoredIn(DataLocation::CallData)
  			)
  			{
  				solAssert(referenceType->isImplicitlyConvertibleTo(*TypeProvider::bytesCalldata()), "");
  				utils().convertType(*referenceType, *TypeProvider::bytesCalldata());
  				utils().abiDecode(targetTypes, false);
  			}
  			else
  			{
  				utils().convertType(*firstArgType, *TypeProvider::bytesMemory());
  				m_context << Instruction::DUP1 << u256(32) << Instruction::ADD;
  				m_context << Instruction::SWAP1 << Instruction::MLOAD;
  				// stack now: <mem_pos> <length>
  
  				utils().abiDecode(targetTypes, true);
  			}
  			break;
  		}
  		case FunctionType::Kind::GasLeft:
  			m_context << Instruction::GAS;
  			break;
  		case FunctionType::Kind::MetaType:
  			// No code to generate.
  			break;
  		}
  	}
  	return false;
  }
  
  bool ExpressionCompiler::visit(FunctionCallOptions const& _functionCallOptions)
  {
  	_functionCallOptions.expression().accept(*this);
  
  	// Desired Stack: [salt], [gas], [value]
  	enum Option { Salt, Gas, Value };
  
  	vector<Option> presentOptions;
  	FunctionType const& funType = dynamic_cast<FunctionType const&>(
  		*_functionCallOptions.expression().annotation().type
  	);
  	if (funType.saltSet()) presentOptions.emplace_back(Salt);
  	if (funType.gasSet()) presentOptions.emplace_back(Gas);
  	if (funType.valueSet()) presentOptions.emplace_back(Value);
  
  	for (size_t i = 0; i < _functionCallOptions.options().size(); ++i)
  	{
  		string const& name = *_functionCallOptions.names()[i];
  		Type const* requiredType = TypeProvider::uint256();
  		Option newOption;
  		if (name == "salt")
  		{
  			newOption = Salt;
  			requiredType = TypeProvider::fixedBytes(32);
  		}
  		else if (name == "gas")
  			newOption = Gas;
  		else if (name == "value")
  			newOption = Value;
  		else
  			solAssert(false, "Unexpected option name!");
  		acceptAndConvert(*_functionCallOptions.options()[i], *requiredType);
  
  		solAssert(!contains(presentOptions, newOption), "");
  		size_t insertPos = presentOptions.end() - lower_bound(presentOptions.begin(), presentOptions.end(), newOption);
  
  		utils().moveIntoStack(insertPos, 1);
  		presentOptions.insert(presentOptions.end() - insertPos, newOption);
  	}
  
  	return false;
  }
  
  bool ExpressionCompiler::visit(NewExpression const&)
  {
  	// code is created for the function call (CREATION) only
  	return false;
  }
  
  bool ExpressionCompiler::visit(MemberAccess const& _memberAccess)
  {
  	CompilerContext::LocationSetter locationSetter(m_context, _memberAccess);
  	// Check whether the member is a bound function.
  	ASTString const& member = _memberAccess.memberName();
  	if (auto funType = dynamic_cast<FunctionType const*>(_memberAccess.annotation().type))
  		if (funType->bound())
  		{
  			acceptAndConvert(_memberAccess.expression(), *funType->selfType(), true);
  			if (funType->kind() == FunctionType::Kind::Internal)
  			{
  				FunctionDefinition const& funDef = dynamic_cast<decltype(funDef)>(funType->declaration());
  				utils().pushCombinedFunctionEntryLabel(funDef);
  				utils().moveIntoStack(funType->selfType()->sizeOnStack(), 1);
  			}
  			else
  			{
  				solAssert(funType->kind() == FunctionType::Kind::DelegateCall, "");
  				auto contract = dynamic_cast<ContractDefinition const*>(funType->declaration().scope());
  				solAssert(contract && contract->isLibrary(), "");
  				m_context.appendLibraryAddress(contract->fullyQualifiedName());
  				m_context << funType->externalIdentifier();
  				utils().moveIntoStack(funType->selfType()->sizeOnStack(), 2);
  			}
  			return false;
  		}
  
  	// Special processing for TypeType because we do not want to visit the library itself
  	// for internal functions, or enum/struct definitions.
  	if (TypeType const* type = dynamic_cast<TypeType const*>(_memberAccess.expression().annotation().type))
  	{
  		if (dynamic_cast<ContractType const*>(type->actualType()))
  		{
  			solAssert(_memberAccess.annotation().type, "_memberAccess has no type");
  			if (auto variable = dynamic_cast<VariableDeclaration const*>(_memberAccess.annotation().referencedDeclaration))
  				appendVariable(*variable, static_cast<Expression const&>(_memberAccess));
  			else if (auto funType = dynamic_cast<FunctionType const*>(_memberAccess.annotation().type))
  			{
  				switch (funType->kind())
  				{
  				case FunctionType::Kind::Declaration:
  					break;
  				case FunctionType::Kind::Internal:
  					// We do not visit the expression here on purpose, because in the case of an
  					// internal library function call, this would push the library address forcing
  					// us to link against it although we actually do not need it.
  					if (auto const* function = dynamic_cast<FunctionDefinition const*>(_memberAccess.annotation().referencedDeclaration))
  						utils().pushCombinedFunctionEntryLabel(*function);
  					else
  						solAssert(false, "Function not found in member access");
  					break;
  				case FunctionType::Kind::Event:
  					if (!dynamic_cast<EventDefinition const*>(_memberAccess.annotation().referencedDeclaration))
  						solAssert(false, "event not found");
  					// no-op, because the parent node will do the job
  					break;
  				case FunctionType::Kind::DelegateCall:
  					_memberAccess.expression().accept(*this);
  					m_context << funType->externalIdentifier();
  					break;
  				case FunctionType::Kind::External:
  				case FunctionType::Kind::Creation:
  				case FunctionType::Kind::Send:
  				case FunctionType::Kind::BareCall:
  				case FunctionType::Kind::BareCallCode:
  				case FunctionType::Kind::BareDelegateCall:
  				case FunctionType::Kind::BareStaticCall:
  				case FunctionType::Kind::Transfer:
  				case FunctionType::Kind::Log0:
  				case FunctionType::Kind::Log1:
  				case FunctionType::Kind::Log2:
  				case FunctionType::Kind::Log3:
  				case FunctionType::Kind::Log4:
  				case FunctionType::Kind::ECRecover:
  				case FunctionType::Kind::SHA256:
  				case FunctionType::Kind::RIPEMD160:
  				default:
  					solAssert(false, "unsupported member function");
  				}
  			}
  			else if (dynamic_cast<TypeType const*>(_memberAccess.annotation().type))
  			{
  				// no-op
  			}
  			else
  				_memberAccess.expression().accept(*this);
  		}
  		else if (auto enumType = dynamic_cast<EnumType const*>(type->actualType()))
  		{
  			_memberAccess.expression().accept(*this);
  			m_context << enumType->memberValue(_memberAccess.memberName());
  		}
  		else
  			_memberAccess.expression().accept(*this);
  		return false;
  	}
  	// Another special case for `this.f.selector` and for ``C.f.selector`` which do not need the address.
  	// There are other uses of `.selector` which do need the address, but we want these
  	// specific uses to be pure expressions.
  	if (
  		auto const* functionType = dynamic_cast<FunctionType const*>(_memberAccess.expression().annotation().type);
  		functionType && member == "selector"
  	)
  	{
  		if (functionType->hasDeclaration())
  		{
  			m_context << functionType->externalIdentifier();
  			/// need to store it as bytes4
  			utils().leftShiftNumberOnStack(224);
  			return false;
  		}
  		else if (auto const* expr = dynamic_cast<MemberAccess const*>(&_memberAccess.expression()))
  			if (auto const* exprInt = dynamic_cast<Identifier const*>(&expr->expression()))
  				if (exprInt->name() == "this")
  					if (Declaration const* declaration = expr->annotation().referencedDeclaration)
  					{
  						u256 identifier;
  						if (auto const* variable = dynamic_cast<VariableDeclaration const*>(declaration))
  							identifier = FunctionType(*variable).externalIdentifier();
  						else if (auto const* function = dynamic_cast<FunctionDefinition const*>(declaration))
  							identifier = FunctionType(*function).externalIdentifier();
  						else
  							solAssert(false, "Contract member is neither variable nor function.");
  						m_context << identifier;
  						/// need to store it as bytes4
  						utils().leftShiftNumberOnStack(224);
  						return false;
  					}
  	}
  	// Another special case for `address(this).balance`. Post-Istanbul, we can use the selfbalance
  	// opcode.
  	if (
  		m_context.evmVersion().hasSelfBalance() &&
  		member == "balance" &&
  		_memberAccess.expression().annotation().type->category() == Type::Category::Address
  	)
  		if (FunctionCall const* funCall = dynamic_cast<FunctionCall const*>(&_memberAccess.expression()))
  			if (auto const* addr = dynamic_cast<ElementaryTypeNameExpression const*>(&funCall->expression()))
  				if (
  					addr->type().typeName().token() == Token::Address &&
  					funCall->arguments().size() == 1
  				)
  					if (auto arg = dynamic_cast<Identifier const*>( funCall->arguments().front().get()))
  						if (
  							arg->name() == "this" &&
  							dynamic_cast<MagicVariableDeclaration const*>(arg->annotation().referencedDeclaration)
  						)
  						{
  							m_context << Instruction::SELFBALANCE;
  							return false;
  						}
  
  	_memberAccess.expression().accept(*this);
  	switch (_memberAccess.expression().annotation().type->category())
  	{
  	case Type::Category::Contract:
  	{
  		ContractType const& type = dynamic_cast<ContractType const&>(*_memberAccess.expression().annotation().type);
  		if (type.isSuper())
  		{
  			solAssert(!!_memberAccess.annotation().referencedDeclaration, "Referenced declaration not resolved.");
  			utils().pushCombinedFunctionEntryLabel(m_context.superFunction(
  				dynamic_cast<FunctionDefinition const&>(*_memberAccess.annotation().referencedDeclaration),
  				type.contractDefinition()
  			));
  		}
  		// ordinary contract type
  		else if (Declaration const* declaration = _memberAccess.annotation().referencedDeclaration)
  		{
  			u256 identifier;
  			if (auto const* variable = dynamic_cast<VariableDeclaration const*>(declaration))
  				identifier = FunctionType(*variable).externalIdentifier();
  			else if (auto const* function = dynamic_cast<FunctionDefinition const*>(declaration))
  				identifier = FunctionType(*function).externalIdentifier();
  			else
  				solAssert(false, "Contract member is neither variable nor function.");
  			utils().convertType(type, type.isPayable() ? *TypeProvider::payableAddress() : *TypeProvider::address(), true);
  			m_context << identifier;
  		}
  		else
  			solAssert(false, "Invalid member access in contract");
  		break;
  	}
  	case Type::Category::Integer:
  	{
  		solAssert(false, "Invalid member access to integer");
  		break;
  	}
  	case Type::Category::Address:
  	{
  		if (member == "balance")
  		{
  			utils().convertType(
  				*_memberAccess.expression().annotation().type,
  				*TypeProvider::address(),
  				true
  			);
  			m_context << Instruction::BALANCE;
  		}
  		else if ((set<string>{"send", "transfer"}).count(member))
  		{
  			solAssert(dynamic_cast<AddressType const&>(*_memberAccess.expression().annotation().type).stateMutability() == StateMutability::Payable, "");
  			utils().convertType(
  				*_memberAccess.expression().annotation().type,
  				AddressType(StateMutability::Payable),
  				true
  			);
  		}
  		else if ((set<string>{"call", "callcode", "delegatecall", "staticcall"}).count(member))
  			utils().convertType(
  				*_memberAccess.expression().annotation().type,
  				*TypeProvider::address(),
  				true
  			);
  		else
  			solAssert(false, "Invalid member access to address");
  		break;
  	}
  	case Type::Category::Function:
  		if (member == "selector")
  		{
  			m_context << Instruction::SWAP1 << Instruction::POP;
  			/// need to store it as bytes4
  			utils().leftShiftNumberOnStack(224);
  		}
  		else if (member == "address")
  		{
  			auto const& functionType = dynamic_cast<FunctionType const&>(*_memberAccess.expression().annotation().type);
  			solAssert(functionType.kind() == FunctionType::Kind::External, "");
  			// stack: <address> <function_id>
  			m_context << Instruction::POP;
  		}
  		else
  			solAssert(
  				!!_memberAccess.expression().annotation().type->memberType(member),
  				"Invalid member access to function."
  			);
  		break;
  	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 << Instruction::COINBASE;
  		else if (member == "timestamp")
  			m_context << Instruction::TIMESTAMP;
  		else if (member == "difficulty")
  			m_context << Instruction::DIFFICULTY;
  		else if (member == "number")
  			m_context << Instruction::NUMBER;
  		else if (member == "gaslimit")
  			m_context << Instruction::GASLIMIT;
  		else if (member == "sender")
  			m_context << Instruction::CALLER;
  		else if (member == "value")
  			m_context << Instruction::CALLVALUE;
  		else if (member == "origin")
  			m_context << Instruction::ORIGIN;
  		else if (member == "gasprice")
  			m_context << Instruction::GASPRICE;
  		else if (member == "data")
  			m_context << u256(0) << Instruction::CALLDATASIZE;
  		else if (member == "sig")
  			m_context << u256(0) << Instruction::CALLDATALOAD
  				<< (u256(0xffffffff) << (256 - 32)) << Instruction::AND;
  		else if (member == "gas")
  			solAssert(false, "Gas has been removed.");
  		else if (member == "blockhash")
  			solAssert(false, "Blockhash has been removed.");
  		else if (member == "creationCode" || member == "runtimeCode")
  		{
  			TypePointer arg = dynamic_cast<MagicType const&>(*_memberAccess.expression().annotation().type).typeArgument();
  			ContractDefinition const& contract = dynamic_cast<ContractType const&>(*arg).contractDefinition();
  			utils().fetchFreeMemoryPointer();
  			m_context << Instruction::DUP1 << u256(32) << Instruction::ADD;
  			utils().copyContractCodeToMemory(contract, member == "creationCode");
  			// Stack: start end
  			m_context.appendInlineAssembly(
  				Whiskers(R"({
  					mstore(start, sub(end, add(start, 0x20)))
  					mstore(<free>, and(add(end, 31), not(31)))
  				})")("free", to_string(CompilerUtils::freeMemoryPointer)).render(),
  				{"start", "end"}
  			);
  			m_context << Instruction::POP;
  		}
  		else if (member == "name")
  		{
  			TypePointer arg = dynamic_cast<MagicType const&>(*_memberAccess.expression().annotation().type).typeArgument();
  			ContractDefinition const& contract = dynamic_cast<ContractType const&>(*arg).contractDefinition();
  			utils().allocateMemory(((contract.name().length() + 31) / 32) * 32 + 32);
  			// store string length
  			m_context << u256(contract.name().length()) << Instruction::DUP2 << Instruction::MSTORE;
  			// adjust pointer
  			m_context << Instruction::DUP1 << u256(32) << Instruction::ADD;
  			utils().storeStringData(contract.name());
  		}
  		else if ((set<string>{"encode", "encodePacked", "encodeWithSelector", "encodeWithSignature", "decode"}).count(member))
  		{
  			// no-op
  		}
  		else
  			solAssert(false, "Unknown magic member.");
  		break;
  	case Type::Category::Struct:
  	{
  		StructType const& type = dynamic_cast<StructType const&>(*_memberAccess.expression().annotation().type);
  		TypePointer const& memberType = _memberAccess.annotation().type;
  		switch (type.location())
  		{
  		case DataLocation::Storage:
  		{
  			pair<u256, unsigned> const& offsets = type.storageOffsetsOfMember(member);
  			m_context << offsets.first << Instruction::ADD << u256(offsets.second);
  			setLValueToStorageItem(_memberAccess);
  			break;
  		}
  		case DataLocation::Memory:
  		{
  			m_context << type.memoryOffsetOfMember(member) << Instruction::ADD;
  			setLValue<MemoryItem>(_memberAccess, *memberType);
  			break;
  		}
  		case DataLocation::CallData:
  		{
  			if (_memberAccess.annotation().type->isDynamicallyEncoded())
  			{
  				m_context << Instruction::DUP1;
  				m_context << type.calldataOffsetOfMember(member) << Instruction::ADD;
  				CompilerUtils(m_context).accessCalldataTail(*memberType);
  			}
  			else
  			{
  				m_context << type.calldataOffsetOfMember(member) << Instruction::ADD;
  				// For non-value types the calldata offset is returned directly.
  				if (memberType->isValueType())
  				{
  					solAssert(memberType->calldataEncodedSize() > 0, "");
  					solAssert(memberType->storageBytes() <= 32, "");
  					if (memberType->storageBytes() < 32 && m_context.experimentalFeatureActive(ExperimentalFeature::ABIEncoderV2))
  					{
  						m_context << u256(32);
  						CompilerUtils(m_context).abiDecodeV2({memberType}, false);
  					}
  					else
  						CompilerUtils(m_context).loadFromMemoryDynamic(*memberType, true, true, false);
  				}
  				else
  					solAssert(
  						memberType->category() == Type::Category::Array ||
  						memberType->category() == Type::Category::Struct,
  						""
  					);
  			}
  			break;
  		}
  		default:
  			solAssert(false, "Illegal data location for struct.");
  		}
  		break;
  	}
  	case Type::Category::Enum:
  	{
  		EnumType const& type = dynamic_cast<EnumType const&>(*_memberAccess.expression().annotation().type);
  		m_context << type.memberValue(_memberAccess.memberName());
  		break;
  	}
  	case Type::Category::Array:
  	{
  		auto const& type = dynamic_cast<ArrayType const&>(*_memberAccess.expression().annotation().type);
  		if (member == "length")
  		{
  			if (!type.isDynamicallySized())
  			{
  				utils().popStackElement(type);
  				m_context << type.length();
  			}
  			else
  				switch (type.location())
  				{
  				case DataLocation::CallData:
  					m_context << Instruction::SWAP1 << Instruction::POP;
  					break;
  				case DataLocation::Storage:
  					ArrayUtils(m_context).retrieveLength(type);
  					m_context << Instruction::SWAP1 << Instruction::POP;
  					break;
  				case DataLocation::Memory:
  					m_context << Instruction::MLOAD;
  					break;
  				}
  		}
  		else if (member == "push" || member == "pop")
  		{
  			solAssert(
  				type.isDynamicallySized() &&
  				type.location() == DataLocation::Storage &&
  				type.category() == Type::Category::Array,
  				"Tried to use ." + member + "() on a non-dynamically sized array"
  			);
  		}
  		else
  			solAssert(false, "Illegal array member.");
  		break;
  	}
  	case Type::Category::FixedBytes:
  	{
  		auto const& type = dynamic_cast<FixedBytesType const&>(*_memberAccess.expression().annotation().type);
  		utils().popStackElement(type);
  		if (member == "length")
  			m_context << u256(type.numBytes());
  		else
  			solAssert(false, "Illegal fixed bytes member.");
  		break;
  	}
  	default:
  		solAssert(false, "Member access to unknown type.");
  	}
  	return false;
  }
  
  bool ExpressionCompiler::visit(IndexAccess const& _indexAccess)
  {
  	CompilerContext::LocationSetter locationSetter(m_context, _indexAccess);
  	_indexAccess.baseExpression().accept(*this);
  
  	Type const& baseType = *_indexAccess.baseExpression().annotation().type;
  
  	switch (baseType.category())
  	{
  		case Type::Category::Mapping:
  		{
  			// stack: storage_base_ref
  			TypePointer keyType = dynamic_cast<MappingType const&>(baseType).keyType();
  			solAssert(_indexAccess.indexExpression(), "Index expression expected.");
  			if (keyType->isDynamicallySized())
  			{
  				_indexAccess.indexExpression()->accept(*this);
  				utils().fetchFreeMemoryPointer();
  				// stack: base index mem
  				// note: the following operations must not allocate memory!
  				utils().packedEncode(
  					TypePointers{_indexAccess.indexExpression()->annotation().type},
  					TypePointers{keyType}
  				);
  				m_context << Instruction::SWAP1;
  				utils().storeInMemoryDynamic(*TypeProvider::uint256());
  				utils().toSizeAfterFreeMemoryPointer();
  			}
  			else
  			{
  				m_context << u256(0); // memory position
  				appendExpressionCopyToMemory(*keyType, *_indexAccess.indexExpression());
  				m_context << Instruction::SWAP1;
  				solAssert(CompilerUtils::freeMemoryPointer >= 0x40, "");
  				utils().storeInMemoryDynamic(*TypeProvider::uint256());
  				m_context << u256(0);
  			}
  			m_context << Instruction::KECCAK256;
  			m_context << u256(0);
  			setLValueToStorageItem(_indexAccess);
  			break;
  		}
  		case Type::Category::ArraySlice:
  		{
  			auto const& arrayType = dynamic_cast<ArraySliceType const&>(baseType).arrayType();
  			solAssert(arrayType.location() == DataLocation::CallData && arrayType.isDynamicallySized(), "");
  			solAssert(_indexAccess.indexExpression(), "Index expression expected.");
  
  			acceptAndConvert(*_indexAccess.indexExpression(), *TypeProvider::uint256(), true);
  			ArrayUtils(m_context).accessCallDataArrayElement(arrayType);
  			break;
  
  		}
  		case Type::Category::Array:
  		{
  			ArrayType const& arrayType = dynamic_cast<ArrayType const&>(baseType);
  			solAssert(_indexAccess.indexExpression(), "Index expression expected.");
  
  			acceptAndConvert(*_indexAccess.indexExpression(), *TypeProvider::uint256(), true);
  			// stack layout: <base_ref> [<length>] <index>
  			switch (arrayType.location())
  			{
  				case DataLocation::Storage:
  					ArrayUtils(m_context).accessIndex(arrayType);
  					if (arrayType.isByteArray())
  					{
  						solAssert(!arrayType.isString(), "Index access to string is not allowed.");
  						setLValue<StorageByteArrayElement>(_indexAccess);
  					}
  					else
  						setLValueToStorageItem(_indexAccess);
  					break;
  				case DataLocation::Memory:
  					ArrayUtils(m_context).accessIndex(arrayType);
  					setLValue<MemoryItem>(_indexAccess, *_indexAccess.annotation().type, !arrayType.isByteArray());
  					break;
  				case DataLocation::CallData:
  					ArrayUtils(m_context).accessCallDataArrayElement(arrayType);
  					break;
  			}
  			break;
  		}
  		case Type::Category::FixedBytes:
  		{
  			FixedBytesType const& fixedBytesType = dynamic_cast<FixedBytesType const&>(baseType);
  			solAssert(_indexAccess.indexExpression(), "Index expression expected.");
  
  			acceptAndConvert(*_indexAccess.indexExpression(), *TypeProvider::uint256(), true);
  			// stack layout: <value> <index>
  			// check out-of-bounds access
  			m_context << u256(fixedBytesType.numBytes());
  			m_context << Instruction::DUP2 << Instruction::LT << Instruction::ISZERO;
  			// out-of-bounds access throws exception
  			m_context.appendConditionalInvalid();
  
  			m_context << Instruction::BYTE;
  			utils().leftShiftNumberOnStack(256 - 8);
  			break;
  		}
  		case Type::Category::TypeType:
  		{
  			solAssert(baseType.sizeOnStack() == 0, "");
  			solAssert(_indexAccess.annotation().type->sizeOnStack() == 0, "");
  			// no-op - this seems to be a lone array type (`structType[];`)
  			break;
  		}
  		default:
  			solAssert(false, "Index access only allowed for mappings or arrays.");
  			break;
  	}
  
  	return false;
  }
  
  bool ExpressionCompiler::visit(IndexRangeAccess const& _indexAccess)
  {
  	CompilerContext::LocationSetter locationSetter(m_context, _indexAccess);
  	_indexAccess.baseExpression().accept(*this);
  	// stack: offset length
  
  	Type const& baseType = *_indexAccess.baseExpression().annotation().type;
  
  	ArrayType const *arrayType = dynamic_cast<ArrayType const*>(&baseType);
  	if (!arrayType)
  		if (ArraySliceType const* sliceType = dynamic_cast<ArraySliceType const*>(&baseType))
  			arrayType = &sliceType->arrayType();
  
  	solAssert(arrayType, "");
  	solUnimplementedAssert(arrayType->location() == DataLocation::CallData && arrayType->isDynamicallySized(), "");
  
  	if (_indexAccess.startExpression())
  		acceptAndConvert(*_indexAccess.startExpression(), *TypeProvider::uint256());
  	else
  		m_context << u256(0);
  	// stack: offset length sliceStart
  
  	m_context << Instruction::SWAP1;
  	// stack: offset sliceStart length
  
  	if (_indexAccess.endExpression())
  		acceptAndConvert(*_indexAccess.endExpression(), *TypeProvider::uint256());
  	else
  		m_context << Instruction::DUP1;
  	// stack: offset sliceStart length sliceEnd
  
  	m_context << Instruction::SWAP3;
  	// stack: sliceEnd sliceStart length offset
  
  	m_context.callYulFunction(m_context.utilFunctions().calldataArrayIndexRangeAccess(*arrayType), 4, 2);
  
  	return false;
  }
  
  void ExpressionCompiler::endVisit(Identifier const& _identifier)
  {
  	CompilerContext::LocationSetter locationSetter(m_context, _identifier);
  	Declaration const* declaration = _identifier.annotation().referencedDeclaration;
  	if (MagicVariableDeclaration const* magicVar = dynamic_cast<MagicVariableDeclaration const*>(declaration))
  	{
  		switch (magicVar->type()->category())
  		{
  		case Type::Category::Contract:
  			// "this" or "super"
  			if (!dynamic_cast<ContractType const&>(*magicVar->type()).isSuper())
  				m_context << Instruction::ADDRESS;
  			break;
  		case Type::Category::Integer:
  			// "now"
  			m_context << Instruction::TIMESTAMP;
  			break;
  		default:
  			break;
  		}
  	}
  	else if (FunctionDefinition const* functionDef = dynamic_cast<FunctionDefinition const*>(declaration))
  		// If the identifier is called right away, this code is executed in visit(FunctionCall...), because
  		// we want to avoid having a reference to the runtime function entry point in the
  		// constructor context, since this would force the compiler to include unreferenced
  		// internal functions in the runtime contex.
  		utils().pushCombinedFunctionEntryLabel(m_context.resolveVirtualFunction(*functionDef));
  	else if (auto variable = dynamic_cast<VariableDeclaration const*>(declaration))
  		appendVariable(*variable, static_cast<Expression const&>(_identifier));
  	else if (auto contract = dynamic_cast<ContractDefinition const*>(declaration))
  	{
  		if (contract->isLibrary())
  			m_context.appendLibraryAddress(contract->fullyQualifiedName());
  	}
  	else if (dynamic_cast<EventDefinition const*>(declaration))
  	{
  		// no-op
  	}
  	else if (dynamic_cast<EnumDefinition const*>(declaration))
  	{
  		// no-op
  	}
  	else if (dynamic_cast<StructDefinition const*>(declaration))
  	{
  		// no-op
  	}
  	else
  	{
  		solAssert(false, "Identifier type not expected in expression context.");
  	}
  }
  
  void ExpressionCompiler::endVisit(Literal const& _literal)
  {
  	CompilerContext::LocationSetter locationSetter(m_context, _literal);
  	TypePointer type = _literal.annotation().type;
  
  	switch (type->category())
  	{
  	case Type::Category::RationalNumber:
  	case Type::Category::Bool:
  	case Type::Category::Address:
  		m_context << type->literalValue(&_literal);
  		break;
  	case Type::Category::StringLiteral:
  		break; // will be done during conversion
  	default:
  		solUnimplemented("Only integer, boolean and string literals implemented for now.");
  	}
  }
  
  void ExpressionCompiler::appendAndOrOperatorCode(BinaryOperation const& _binaryOperation)
  {
  	Token const c_op = _binaryOperation.getOperator();
  	solAssert(c_op == Token::Or || c_op == Token::And, "");
  
  	_binaryOperation.leftExpression().accept(*this);
  	m_context << Instruction::DUP1;
  	if (c_op == Token::And)
  		m_context << Instruction::ISZERO;
  	evmasm::AssemblyItem endLabel = m_context.appendConditionalJump();
  	m_context << Instruction::POP;
  	_binaryOperation.rightExpression().accept(*this);
  	m_context << endLabel;
  }
  
  void ExpressionCompiler::appendCompareOperatorCode(Token _operator, Type const& _type)
  {
  	solAssert(_type.sizeOnStack() == 1, "Comparison of multi-slot types.");
  	if (_operator == Token::Equal || _operator == Token::NotEqual)
  	{
  		if (FunctionType const* funType = dynamic_cast<decltype(funType)>(&_type))
  		{
  			if (funType->kind() == FunctionType::Kind::Internal)
  			{
  				// We have to remove the upper bits (construction time value) because they might
  				// be "unknown" in one of the operands and not in the other.
  				m_context << ((u256(1) << 32) - 1) << Instruction::AND;
  				m_context << Instruction::SWAP1;
  				m_context << ((u256(1) << 32) - 1) << Instruction::AND;
  			}
  		}
  		m_context << Instruction::EQ;
  		if (_operator == Token::NotEqual)
  			m_context << Instruction::ISZERO;
  	}
  	else
  	{
  		bool isSigned = false;
  		if (auto type = dynamic_cast<IntegerType const*>(&_type))
  			isSigned = type->isSigned();
  
  		switch (_operator)
  		{
  		case Token::GreaterThanOrEqual:
  			m_context <<
  				(isSigned ? Instruction::SLT : Instruction::LT) <<
  				Instruction::ISZERO;
  			break;
  		case Token::LessThanOrEqual:
  			m_context <<
  				(isSigned ? Instruction::SGT : Instruction::GT) <<
  				Instruction::ISZERO;
  			break;
  		case Token::GreaterThan:
  			m_context << (isSigned ? Instruction::SGT : Instruction::GT);
  			break;
  		case Token::LessThan:
  			m_context << (isSigned ? Instruction::SLT : Instruction::LT);
  			break;
  		default:
  			solAssert(false, "Unknown comparison operator.");
  		}
  	}
  }
  
  void ExpressionCompiler::appendOrdinaryBinaryOperatorCode(Token _operator, Type const& _type)
  {
  	if (TokenTraits::isArithmeticOp(_operator))
  		appendArithmeticOperatorCode(_operator, _type);
  	else if (TokenTraits::isBitOp(_operator))
  		appendBitOperatorCode(_operator);
  	else
  		solAssert(false, "Unknown binary operator.");
  }
  
  void ExpressionCompiler::appendArithmeticOperatorCode(Token _operator, Type const& _type)
  {
  	if (_type.category() == Type::Category::FixedPoint)
  		solUnimplemented("Not yet implemented - FixedPointType.");
  
  	IntegerType const& type = dynamic_cast<IntegerType const&>(_type);
  	bool const c_isSigned = type.isSigned();
  
  	switch (_operator)
  	{
  	case Token::Add:
  		m_context << Instruction::ADD;
  		break;
  	case Token::Sub:
  		m_context << Instruction::SUB;
  		break;
  	case Token::Mul:
  		m_context << Instruction::MUL;
  		break;
  	case Token::Div:
  	case Token::Mod:
  	{
  		// Test for division by zero
  		m_context << Instruction::DUP2 << Instruction::ISZERO;
  		m_context.appendConditionalInvalid();
  
  		if (_operator == Token::Div)
  			m_context << (c_isSigned ? Instruction::SDIV : Instruction::DIV);
  		else
  			m_context << (c_isSigned ? Instruction::SMOD : Instruction::MOD);
  		break;
  	}
  	case Token::Exp:
  		m_context << Instruction::EXP;
  		break;
  	default:
  		solAssert(false, "Unknown arithmetic operator.");
  	}
  }
  
  void ExpressionCompiler::appendBitOperatorCode(Token _operator)
  {
  	switch (_operator)
  	{
  	case Token::BitOr:
  		m_context << Instruction::OR;
  		break;
  	case Token::BitAnd:
  		m_context << Instruction::AND;
  		break;
  	case Token::BitXor:
  		m_context << Instruction::XOR;
  		break;
  	default:
  		solAssert(false, "Unknown bit operator.");
  	}
  }
  
  void ExpressionCompiler::appendShiftOperatorCode(Token _operator, Type const& _valueType, Type const& _shiftAmountType)
  {
  	// stack: shift_amount value_to_shift
  
  	bool c_valueSigned = false;
  	if (auto valueType = dynamic_cast<IntegerType const*>(&_valueType))
  		c_valueSigned = valueType->isSigned();
  	else
  		solAssert(dynamic_cast<FixedBytesType const*>(&_valueType), "Only integer and fixed bytes type supported for shifts.");
  
  	// The amount can be a RationalNumberType too.
  	bool c_amountSigned = false;
  	if (auto amountType = dynamic_cast<RationalNumberType const*>(&_shiftAmountType))
  	{
  		// This should be handled by the type checker.
  		solAssert(amountType->integerType(), "");
  		solAssert(!amountType->integerType()->isSigned(), "");
  	}
  	else if (auto amountType = dynamic_cast<IntegerType const*>(&_shiftAmountType))
  		c_amountSigned = amountType->isSigned();
  	else
  		solAssert(false, "Invalid shift amount type.");
  
  	// shift by negative amount throws exception
  	if (c_amountSigned)
  	{
  		m_context << u256(0) << Instruction::DUP3 << Instruction::SLT;
  		m_context.appendConditionalInvalid();
  	}
  
  	m_context << Instruction::SWAP1;
  	// stack: value_to_shift shift_amount
  
  	switch (_operator)
  	{
  	case Token::SHL:
  		if (m_context.evmVersion().hasBitwiseShifting())
  			m_context << Instruction::SHL;
  		else
  			m_context << u256(2) << Instruction::EXP << Instruction::MUL;
  		break;
  	case Token::SAR:
  		if (m_context.evmVersion().hasBitwiseShifting())
  			m_context << (c_valueSigned ? Instruction::SAR : Instruction::SHR);
  		else
  		{
  			if (c_valueSigned)
  				// In the following assembly snippet, xor_mask will be zero, if value_to_shift is positive.
  				// Therefore xor'ing with xor_mask is the identity and the computation reduces to
  				// div(value_to_shift, exp(2, shift_amount)), which is correct, since for positive values
  				// arithmetic right shift is dividing by a power of two (which, as a bitwise operation, results
  				// in discarding bits on the right and filling with zeros from the left).
  				// For negative values arithmetic right shift, viewed as a bitwise operation, discards bits to the
  				// right and fills in ones from the left. This is achieved as follows:
  				// If value_to_shift is negative, then xor_mask will have all bits set, so xor'ing with xor_mask
  				// will flip all bits. First all bits in value_to_shift are flipped. As for the positive case,
  				// dividing by a power of two using integer arithmetic results in discarding bits to the right
  				// and filling with zeros from the left. Flipping all bits in the result again, turns all zeros
  				// on the left to ones and restores the non-discarded, shifted bits to their original value (they
  				// have now been flipped twice). In summary we now have discarded bits to the right and filled with
  				// ones from the left, i.e. we have performed an arithmetic right shift.
  				m_context.appendInlineAssembly(R"({
  					let xor_mask := sub(0, slt(value_to_shift, 0))
  					value_to_shift := xor(div(xor(value_to_shift, xor_mask), exp(2, shift_amount)), xor_mask)
  				})", {"value_to_shift", "shift_amount"});
  			else
  				m_context.appendInlineAssembly(R"({
  					value_to_shift := div(value_to_shift, exp(2, shift_amount))
  				})", {"value_to_shift", "shift_amount"});
  			m_context << Instruction::POP;
  
  		}
  		break;
  	case Token::SHR:
  	default:
  		solAssert(false, "Unknown shift operator.");
  	}
  }
  
  void ExpressionCompiler::appendExternalFunctionCall(
  	FunctionType const& _functionType,
  	vector<ASTPointer<Expression const>> const& _arguments,
  	bool _tryCall
  )
  {
  	solAssert(
  		_functionType.takesArbitraryParameters() ||
  		_arguments.size() == _functionType.parameterTypes().size(), ""
  	);
  
  	// Assumed stack content here:
  	// <stack top>
  	// value [if _functionType.valueSet()]
  	// gas [if _functionType.gasSet()]
  	// self object [if bound - moved to top right away]
  	// function identifier [unless bare]
  	// contract address
  
  	unsigned selfSize = _functionType.bound() ? _functionType.selfType()->sizeOnStack() : 0;
  	unsigned gasValueSize = (_functionType.gasSet() ? 1 : 0) + (_functionType.valueSet() ? 1 : 0);
  	unsigned contractStackPos = m_context.currentToBaseStackOffset(1 + gasValueSize + selfSize + (_functionType.isBareCall() ? 0 : 1));
  	unsigned gasStackPos = m_context.currentToBaseStackOffset(gasValueSize);
  	unsigned valueStackPos = m_context.currentToBaseStackOffset(1);
  
  	// move self object to top
  	if (_functionType.bound())
  		utils().moveToStackTop(gasValueSize, _functionType.selfType()->sizeOnStack());
  
  	auto funKind = _functionType.kind();
  
  	solAssert(funKind != FunctionType::Kind::BareStaticCall || m_context.evmVersion().hasStaticCall(), "");
  
  	solAssert(funKind != FunctionType::Kind::BareCallCode, "Callcode has been removed.");
  
  	bool returnSuccessConditionAndReturndata = funKind == FunctionType::Kind::BareCall || funKind == FunctionType::Kind::BareDelegateCall || funKind == FunctionType::Kind::BareStaticCall;
  	bool isDelegateCall = funKind == FunctionType::Kind::BareDelegateCall || funKind == FunctionType::Kind::DelegateCall;
  	bool useStaticCall = funKind == FunctionType::Kind::BareStaticCall || (_functionType.stateMutability() <= StateMutability::View && m_context.evmVersion().hasStaticCall());
  
  	if (_tryCall)
  	{
  		solAssert(!returnSuccessConditionAndReturndata, "");
  		solAssert(!_functionType.isBareCall(), "");
  	}
  
  	bool haveReturndatacopy = m_context.evmVersion().supportsReturndata();
  	unsigned retSize = 0;
  	bool dynamicReturnSize = false;
  	TypePointers returnTypes;
  	if (!returnSuccessConditionAndReturndata)
  	{
  		if (haveReturndatacopy)
  			returnTypes = _functionType.returnParameterTypes();
  		else
  			returnTypes = _functionType.returnParameterTypesWithoutDynamicTypes();
  
  		for (auto const& retType: returnTypes)
  			if (retType->isDynamicallyEncoded())
  			{
  				solAssert(haveReturndatacopy, "");
  				dynamicReturnSize = true;
  				retSize = 0;
  				break;
  			}
  			else if (retType->decodingType())
  				retSize += retType->decodingType()->calldataEncodedSize();
  			else
  				retSize += retType->calldataEncodedSize();
  	}
  
  	// Evaluate arguments.
  	TypePointers argumentTypes;
  	TypePointers parameterTypes = _functionType.parameterTypes();
  	if (_functionType.bound())
  	{
  		argumentTypes.push_back(_functionType.selfType());
  		parameterTypes.insert(parameterTypes.begin(), _functionType.selfType());
  	}
  	for (size_t i = 0; i < _arguments.size(); ++i)
  	{
  		_arguments[i]->accept(*this);
  		argumentTypes.push_back(_arguments[i]->annotation().type);
  	}
  
  	if (funKind == FunctionType::Kind::ECRecover)
  	{
  		// Clears 32 bytes of currently free memory and advances free memory pointer.
  		// Output area will be "start of input area" - 32.
  		// The reason is that a failing ECRecover cannot be detected, it will just return
  		// zero bytes (which we cannot detect).
  		solAssert(0 < retSize && retSize <= 32, "");
  		utils().fetchFreeMemoryPointer();
  		m_context << u256(0) << Instruction::DUP2 << Instruction::MSTORE;
  		m_context << u256(32) << Instruction::ADD;
  		utils().storeFreeMemoryPointer();
  	}
  
  	if (!m_context.evmVersion().canOverchargeGasForCall())
  	{
  		// Touch the end of the output area so that we do not pay for memory resize during the call
  		// (which we would have to subtract from the gas left)
  		// We could also just use MLOAD; POP right before the gas calculation, but the optimizer
  		// would remove that, so we use MSTORE here.
  		if (!_functionType.gasSet() && retSize > 0)
  		{
  			m_context << u256(0);
  			utils().fetchFreeMemoryPointer();
  			// This touches too much, but that way we save some rounding arithmetic
  			m_context << u256(retSize) << Instruction::ADD << Instruction::MSTORE;
  		}
  	}
  
  	// Copy function identifier to memory.
  	utils().fetchFreeMemoryPointer();
  	if (!_functionType.isBareCall())
  	{
  		m_context << dupInstruction(2 + gasValueSize + CompilerUtils::sizeOnStack(argumentTypes));
  		utils().storeInMemoryDynamic(IntegerType(8 * CompilerUtils::dataStartOffset), false);
  	}
  
  	// If the function takes arbitrary parameters or is a bare call, copy dynamic length data in place.
  	// Move arguments to memory, will not update the free memory pointer (but will update the memory
  	// pointer on the stack).
  	bool encodeInPlace = _functionType.takesArbitraryParameters() || _functionType.isBareCall();
  	if (_functionType.kind() == FunctionType::Kind::ECRecover)
  		// This would be the only combination of padding and in-place encoding,
  		// but all parameters of ecrecover are value types anyway.
  		encodeInPlace = false;
  	bool encodeForLibraryCall = funKind == FunctionType::Kind::DelegateCall;
  	utils().encodeToMemory(
  		argumentTypes,
  		parameterTypes,
  		_functionType.padArguments(),
  		encodeInPlace,
  		encodeForLibraryCall
  	);
  
  	// Stack now:
  	// <stack top>
  	// input_memory_end
  	// value [if _functionType.valueSet()]
  	// gas [if _functionType.gasSet()]
  	// function identifier [unless bare]
  	// contract address
  
  	// Output data will replace input data, unless we have ECRecover (then, output
  	// area will be 32 bytes just before input area).
  	// put on stack: <size of output> <memory pos of output> <size of input> <memory pos of input>
  	m_context << u256(retSize);
  	utils().fetchFreeMemoryPointer(); // This is the start of input
  	if (funKind == FunctionType::Kind::ECRecover)
  	{
  		// In this case, output is 32 bytes before input and has already been cleared.
  		m_context << u256(32) << Instruction::DUP2 << Instruction::SUB << Instruction::SWAP1;
  		// Here: <input end> <output size> <outpos> <input pos>
  		m_context << Instruction::DUP1 << Instruction::DUP5 << Instruction::SUB;
  		m_context << Instruction::SWAP1;
  	}
  	else
  	{
  		m_context << Instruction::DUP1 << Instruction::DUP4 << Instruction::SUB;
  		m_context << Instruction::DUP2;
  	}
  
  	// CALL arguments: outSize, outOff, inSize, inOff (already present up to here)
  	// [value,] addr, gas (stack top)
  	if (isDelegateCall)
  		solAssert(!_functionType.valueSet(), "Value set for delegatecall");
  	else if (useStaticCall)
  		solAssert(!_functionType.valueSet(), "Value set for staticcall");
  	else if (_functionType.valueSet())
  		m_context << dupInstruction(m_context.baseToCurrentStackOffset(valueStackPos));
  	else
  		m_context << u256(0);
  	m_context << dupInstruction(m_context.baseToCurrentStackOffset(contractStackPos));
  
  	bool existenceChecked = false;
  	// Check the target contract exists (has code) for non-low-level calls.
  	if (funKind == FunctionType::Kind::External || funKind == FunctionType::Kind::DelegateCall)
  	{
  		m_context << Instruction::DUP1 << Instruction::EXTCODESIZE << Instruction::ISZERO;
  		m_context.appendConditionalRevert(false, "Target contract does not contain code");
  		existenceChecked = true;
  	}
  
  	if (_functionType.gasSet())
  		m_context << dupInstruction(m_context.baseToCurrentStackOffset(gasStackPos));
  	else if (m_context.evmVersion().canOverchargeGasForCall())
  		// Send all gas (requires tangerine whistle EVM)
  		m_context << Instruction::GAS;
  	else
  	{
  		// send all gas except the amount needed to execute "SUB" and "CALL"
  		// @todo this retains too much gas for now, needs to be fine-tuned.
  		u256 gasNeededByCaller = evmasm::GasCosts::callGas(m_context.evmVersion()) + 10;
  		if (_functionType.valueSet())
  			gasNeededByCaller += evmasm::GasCosts::callValueTransferGas;
  		if (!existenceChecked)
  			gasNeededByCaller += evmasm::GasCosts::callNewAccountGas; // we never know
  		m_context << gasNeededByCaller << Instruction::GAS << Instruction::SUB;
  	}
  	// Order is important here, STATICCALL might overlap with DELEGATECALL.
  	if (isDelegateCall)
  		m_context << Instruction::DELEGATECALL;
  	else if (useStaticCall)
  		m_context << Instruction::STATICCALL;
  	else
  		m_context << Instruction::CALL;
  
  	unsigned remainsSize =
  		2 + // contract address, input_memory_end
  		(_functionType.valueSet() ? 1 : 0) +
  		(_functionType.gasSet() ? 1 : 0) +
  		(!_functionType.isBareCall() ? 1 : 0);
  
  	evmasm::AssemblyItem endTag = m_context.newTag();
  
  	if (!returnSuccessConditionAndReturndata && !_tryCall)
  	{
  		// Propagate error condition (if CALL pushes 0 on stack).
  		m_context << Instruction::ISZERO;
  		m_context.appendConditionalRevert(true);
  	}
  	else
  		m_context << swapInstruction(remainsSize);
  	utils().popStackSlots(remainsSize);
  
  	// Only success flag is remaining on stack.
  
  	if (_tryCall)
  	{
  		m_context << Instruction::DUP1 << Instruction::ISZERO;
  		m_context.appendConditionalJumpTo(endTag);
  		m_context << Instruction::POP;
  	}
  
  	if (returnSuccessConditionAndReturndata)
  	{
  		// success condition is already there
  		// The return parameter types can be empty, when this function is used as
  		// an internal helper function e.g. for ``send`` and ``transfer``. In that
  		// case we're only interested in the success condition, not the return data.
  		if (!_functionType.returnParameterTypes().empty())
  			utils().returnDataToArray();
  	}
  	else if (funKind == FunctionType::Kind::RIPEMD160)
  	{
  		// fix: built-in contract returns right-aligned data
  		utils().fetchFreeMemoryPointer();
  		utils().loadFromMemoryDynamic(IntegerType(160), false, true, false);
  		utils().convertType(IntegerType(160), FixedBytesType(20));
  	}
  	else if (funKind == FunctionType::Kind::ECRecover)
  	{
  		// Output is 32 bytes before input / free mem pointer.
  		// Failing ecrecover cannot be detected, so we clear output before the call.
  		m_context << u256(32);
  		utils().fetchFreeMemoryPointer();
  		m_context << Instruction::SUB << Instruction::MLOAD;
  	}
  	else if (!returnTypes.empty())
  	{
  		utils().fetchFreeMemoryPointer();
  		// Stack: return_data_start
  
  		// The old decoder did not allocate any memory (i.e. did not touch the free
  		// memory pointer), but kept references to the return data for
  		// (statically-sized) arrays
  		bool needToUpdateFreeMemoryPtr = false;
  		if (dynamicReturnSize || m_context.experimentalFeatureActive(ExperimentalFeature::ABIEncoderV2))
  			needToUpdateFreeMemoryPtr = true;
  		else
  			for (auto const& retType: returnTypes)
  				if (dynamic_cast<ReferenceType const*>(retType))
  					needToUpdateFreeMemoryPtr = true;
  
  		// Stack: return_data_start
  		if (dynamicReturnSize)
  		{
  			solAssert(haveReturndatacopy, "");
  			m_context.appendInlineAssembly("{ returndatacopy(return_data_start, 0, returndatasize()) }", {"return_data_start"});
  		}
  		else
  			solAssert(retSize > 0, "");
  		// Always use the actual return length, and not our calculated expected length, if returndatacopy is supported.
  		// This ensures it can catch badly formatted input from external calls.
  		m_context << (haveReturndatacopy ? evmasm::AssemblyItem(Instruction::RETURNDATASIZE) : u256(retSize));
  		// Stack: return_data_start return_data_size
  		if (needToUpdateFreeMemoryPtr)
  			m_context.appendInlineAssembly(R"({
  				// round size to the next multiple of 32
  				let newMem := add(start, and(add(size, 0x1f), not(0x1f)))
  				mstore(0x40, newMem)
  			})", {"start", "size"});
  
  		utils().abiDecode(returnTypes, true);
  	}
  
  	if (_tryCall)
  	{
  		// Success branch will reach this, failure branch will directly jump to endTag.
  		m_context << u256(1);
  		m_context << endTag;
  	}
  }
  
  void ExpressionCompiler::appendExpressionCopyToMemory(Type const& _expectedType, Expression const& _expression)
  {
  	solUnimplementedAssert(_expectedType.isValueType(), "Not implemented for non-value types.");
  	acceptAndConvert(_expression, _expectedType, true);
  	utils().storeInMemoryDynamic(_expectedType);
  }
  
  void ExpressionCompiler::appendVariable(VariableDeclaration const& _variable, Expression const& _expression)
  {
  	if (_variable.isConstant())
  		acceptAndConvert(*_variable.value(), *_variable.annotation().type);
  	else if (_variable.immutable())
  		solUnimplemented("");
  	else
  		setLValueFromDeclaration(_variable, _expression);
  }
  
  void ExpressionCompiler::setLValueFromDeclaration(Declaration const& _declaration, Expression const& _expression)
  {
  	if (m_context.isLocalVariable(&_declaration))
  		setLValue<StackVariable>(_expression, dynamic_cast<VariableDeclaration const&>(_declaration));
  	else if (m_context.isStateVariable(&_declaration))
  		setLValue<StorageItem>(_expression, dynamic_cast<VariableDeclaration const&>(_declaration));
  	else
  		BOOST_THROW_EXCEPTION(InternalCompilerError()
  			<< errinfo_sourceLocation(_expression.location())
  			<< errinfo_comment("Identifier type not supported or identifier not found."));
  }
  
  void ExpressionCompiler::setLValueToStorageItem(Expression const& _expression)
  {
  	setLValue<StorageItem>(_expression, *_expression.annotation().type);
  }
  
  bool ExpressionCompiler::cleanupNeededForOp(Type::Category _type, Token _op)
  {
  	if (TokenTraits::isCompareOp(_op) || TokenTraits::isShiftOp(_op))
  		return true;
  	else if (_type == Type::Category::Integer && (_op == Token::Div || _op == Token::Mod || _op == Token::Exp))
  		// We need cleanup for EXP because 0**0 == 1, but 0**0x100 == 0
  		// It would suffice to clean the exponent, though.
  		return true;
  	else
  		return false;
  }
  
  void ExpressionCompiler::acceptAndConvert(Expression const& _expression, Type const& _type, bool _cleanupNeeded)
  {
  	_expression.accept(*this);
  	utils().convertType(*_expression.annotation().type, _type, _cleanupNeeded);
  }
  
  CompilerUtils ExpressionCompiler::utils()
  {
  	return CompilerUtils(m_context);
  }
  