solidity/libsolidity/analysis/ConstantEvaluator.cpp

/*
	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 2015
 * Evaluator for types of constant expressions.
 */

#include <libsolidity/analysis/ConstantEvaluator.h>
#include <libsolidity/ast/AST.h>
#include <libsolidity/interface/ErrorReporter.h>

using namespace std;
using namespace dev;
using namespace dev::solidity;

/// FIXME: this is pretty much a copy of TypeChecker::endVisit(BinaryOperation)
void ConstantEvaluator::endVisit(UnaryOperation const& _operation)
{
	TypePointer const& subType = _operation.subExpression().annotation().type;
	if (!dynamic_cast<RationalNumberType const*>(subType.get()))
		m_errorReporter.fatalTypeError(_operation.subExpression().location(), "Invalid constant expression.");
	TypePointer t = subType->unaryOperatorResult(_operation.getOperator());
	_operation.annotation().type = t;
}

/// FIXME: this is pretty much a copy of TypeChecker::endVisit(BinaryOperation)
void ConstantEvaluator::endVisit(BinaryOperation const& _operation)
{
	TypePointer const& leftType = _operation.leftExpression().annotation().type;
	TypePointer const& rightType = _operation.rightExpression().annotation().type;
	if (!dynamic_cast<RationalNumberType const*>(leftType.get()))
		m_errorReporter.fatalTypeError(_operation.leftExpression().location(), "Invalid constant expression.");
	if (!dynamic_cast<RationalNumberType const*>(rightType.get()))
		m_errorReporter.fatalTypeError(_operation.rightExpression().location(), "Invalid constant expression.");
	TypePointer commonType = leftType->binaryOperatorResult(_operation.getOperator(), rightType);
	if (!commonType)
	{
		m_errorReporter.typeError(
			_operation.location(),
			"Operator " +
			string(Token::toString(_operation.getOperator())) +
			" not compatible with types " +
			leftType->toString() +
			" and " +
			rightType->toString()
		);
		commonType = leftType;
	}
	_operation.annotation().commonType = commonType;
	_operation.annotation().type =
		Token::isCompareOp(_operation.getOperator()) ?
		make_shared<BoolType>() :
		commonType;
}

void ConstantEvaluator::endVisit(Literal const& _literal)
{
	_literal.annotation().type = Type::forLiteral(_literal);
	if (!_literal.annotation().type)
		m_errorReporter.fatalTypeError(_literal.location(), "Invalid literal value.");
}

void ConstantEvaluator::endVisit(Identifier const& _identifier)
{
	VariableDeclaration const* variableDeclaration = dynamic_cast<VariableDeclaration const*>(_identifier.annotation().referencedDeclaration);
	if (!variableDeclaration)
		return;
	if (!variableDeclaration->isConstant())
		m_errorReporter.fatalTypeError(_identifier.location(), "Identifier must be declared constant.");

	ASTPointer<Expression> value = variableDeclaration->value();
	if (!value)
		m_errorReporter.fatalTypeError(_identifier.location(), "Constant identifier declaration must have a constant value.");

	if (!value->annotation().type)
	{
		if (m_depth > 32)
			m_errorReporter.fatalTypeError(_identifier.location(), "Cyclic constant definition.");
		ConstantEvaluator e(*value, m_errorReporter, m_depth + 1);
	}

	_identifier.annotation().type = value->annotation().type;
}