/*
This file is part of cpp-ethereum.
cpp-ethereum 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.
cpp-ethereum 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 cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @author Christian <c@ethdev.com>
* @date 2015
* Component that translates Solidity code into the why3 programming language.
*/
#include <libsolidity/formal/Why3Translator.h>
using namespace std;
using namespace dev;
using namespace dev::solidity;
bool Why3Translator::process(SourceUnit const& _source)
{
try
{
m_indentation = 0;
if (!m_result.empty())
fatalError(_source, "Multiple source units not yet supported");
appendPreface();
_source.accept(*this);
addLine("end");
}
catch (FatalError& _e)
{
solAssert(m_errorOccured, "");
}
return !m_errorOccured;
}
void Why3Translator::error(ASTNode const& _node, string const& _description)
{
auto err = make_shared<Error>(Error::Type::FormalError);
*err <<
errinfo_sourceLocation(_node.location()) <<
errinfo_comment(_description);
m_errors.push_back(err);
m_errorOccured = true;
}
void Why3Translator::fatalError(ASTNode const& _node, string const& _description)
{
error(_node, _description);
BOOST_THROW_EXCEPTION(FatalError());
}
void Why3Translator::appendPreface()
{
m_result += R"(
module UInt256
use import mach.int.Unsigned
type uint256
constant max_uint256: int = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
clone export mach.int.Unsigned with
type t = uint256,
constant max = max_uint256
end
module Solidity
use import int.Int
use import ref.Ref
use import map.Map
use import array.Array
use import int.ComputerDivision
use import mach.int.Unsigned
use import UInt256
exception Ret
type state = StateUnused
)";
}
string Why3Translator::toFormalType(Type const& _type) const
{
if (auto type = dynamic_cast<IntegerType const*>(&_type))
{
if (!type->isAddress() && !type->isSigned() && type->numBits() == 256)
return "uint256";
}
else if (auto type = dynamic_cast<ArrayType const*>(&_type))
if (!type->isByteArray() && type->isDynamicallySized() && type->dataStoredIn(DataLocation::Memory))
{
string base = toFormalType(*type->baseType());
if (!base.empty())
return "array " + base;
}
return "";
}
void Why3Translator::addLine(string const& _line)
{
newLine();
add(_line);
newLine();
}
void Why3Translator::add(string const& _str)
{
m_currentLine += _str;
}
void Why3Translator::newLine()
{
if (!m_currentLine.empty())
{
for (size_t i = 0; i < m_indentation; ++i)
m_result.push_back('\t');
m_result += m_currentLine;
m_result.push_back('\n');
m_currentLine.clear();
}
}
void Why3Translator::unindent()
{
solAssert(m_indentation > 0, "");
m_indentation--;
}
bool Why3Translator::visit(ContractDefinition const& _contract)
{
if (m_seenContract)
error(_contract, "More than one contract not supported.");
m_seenContract = true;
if (_contract.isLibrary())
error(_contract, "Libraries not supported.");
addSourceFromDocStrings(_contract.annotation());
return true;
}
bool Why3Translator::visit(FunctionDefinition const& _function)
{
if (!_function.isImplemented())
{
error(_function, "Unimplemented functions not supported.");
return false;
}
if (_function.name().empty())
{
error(_function, "Fallback functions not supported.");
return false;
}
if (!_function.modifiers().empty())
{
error(_function, "Modifiers not supported.");
return false;
}
add("let rec _" + _function.name());
add(" (state: state)");
for (auto const& param: _function.parameters())
{
string paramType = toFormalType(*param->annotation().type);
if (paramType.empty())
error(*param, "Parameter type not supported.");
if (param->name().empty())
error(*param, "Anonymous function parameters not supported.");
add(" (arg_" + param->name() + ": " + paramType + ")");
}
add(":");
newLine();
indent();
indent();
string retString = "(";
for (auto const& retParam: _function.returnParameters())
{
string paramType = toFormalType(*retParam->annotation().type);
if (paramType.empty())
error(*retParam, "Parameter type not supported.");
if (retString.size() != 1)
retString += ", ";
retString += paramType;
}
addLine(retString + ")");
unindent();
addSourceFromDocStrings(_function.annotation());
addLine("=");
// initialise local variables
for (auto const& variable: _function.parameters())
addLine("let _" + variable->name() + " = ref arg_" + variable->name() + " in");
for (auto const& variable: _function.returnParameters())
{
if (variable->name().empty())
error(*variable, "Unnamed return variables not yet supported.");
string varType = toFormalType(*variable->annotation().type);
addLine("let _" + variable->name() + ": ref " + varType + " = ref (of_int 0) in");
}
for (VariableDeclaration const* variable: _function.localVariables())
{
if (variable->name().empty())
error(*variable, "Unnamed variables not yet supported.");
string varType = toFormalType(*variable->annotation().type);
addLine("let _" + variable->name() + ": ref " + varType + " = ref (of_int 0) in");
}
addLine("try");
_function.body().accept(*this);
addLine("raise Ret");
string retVals;
for (auto const& variable: _function.returnParameters())
{
if (!retVals.empty())
retVals += ", ";
retVals += "!_" + variable->name();
}
addLine("with Ret -> (" + retVals + ")");
newLine();
unindent();
addLine("end");
addLine("");
return false;
}
bool Why3Translator::visit(Block const& _node)
{
addSourceFromDocStrings(_node.annotation());
addLine("begin");
indent();
return true;
}
bool Why3Translator::visit(IfStatement const& _node)
{
addSourceFromDocStrings(_node.annotation());
add("if ");
_node.condition().accept(*this);
add(" then");
newLine();
_node.trueStatement().accept(*this);
if (_node.falseStatement())
{
addLine("else");
_node.falseStatement()->accept(*this);
}
return false;
}
bool Why3Translator::visit(WhileStatement const& _node)
{
addSourceFromDocStrings(_node.annotation());
add("while ");
_node.condition().accept(*this);
add(" do");
newLine();
_node.body().accept(*this);
addLine("done;");
return false;
}
bool Why3Translator::visit(Return const& _node)
{
addSourceFromDocStrings(_node.annotation());
if (_node.expression())
{
solAssert(!!_node.annotation().functionReturnParameters, "");
auto const& params = _node.annotation().functionReturnParameters->parameters();
if (params.size() != 1)
{
error(_node, "Directly returning tuples not supported. Rather assign to return variable.");
return false;
}
newLine();
add("begin _" + params.front()->name() + " := ");
_node.expression()->accept(*this);
add("; raise Ret end");
newLine();
}
else
addLine("raise Ret;");
return false;
}
bool Why3Translator::visit(VariableDeclarationStatement const& _node)
{
addSourceFromDocStrings(_node.annotation());
if (_node.declarations().size() != 1)
{
error(_node, "Multiple variables not supported.");
return false;
}
if (_node.initialValue())
{
add("_" + _node.declarations().front()->name() + " := ");
_node.initialValue()->accept(*this);
add(";");
newLine();
}
return false;
}
bool Why3Translator::visit(ExpressionStatement const& _node)
{
addSourceFromDocStrings(_node.annotation());
return true;
}
bool Why3Translator::visit(Assignment const& _node)
{
if (_node.assignmentOperator() != Token::Assign)
error(_node, "Compound assignment not supported.");
_node.leftHandSide().accept(*this);
add(" := ");
_node.rightHandSide().accept(*this);
return false;
}
bool Why3Translator::visit(TupleExpression const& _node)
{
if (_node.components().size() != 1)
error(_node, "Only tuples with exactly one component supported.");
add("(");
return true;
}
bool Why3Translator::visit(UnaryOperation const& _unaryOperation)
{
if (toFormalType(*_unaryOperation.annotation().type).empty())
error(_unaryOperation, "Type not supported.");
switch (_unaryOperation.getOperator())
{
case Token::Not: // !
add("(not ");
break;
default:
error(_unaryOperation, "Operator not supported.");
break;
}
_unaryOperation.subExpression().accept(*this);
add(")");
return false;
}
bool Why3Translator::visit(BinaryOperation const& _binaryOperation)
{
Expression const& leftExpression = _binaryOperation.leftExpression();
Expression const& rightExpression = _binaryOperation.rightExpression();
solAssert(!!_binaryOperation.annotation().commonType, "");
Type const& commonType = *_binaryOperation.annotation().commonType;
Token::Value const c_op = _binaryOperation.getOperator();
if (commonType.category() == Type::Category::IntegerConstant)
{
add("(of_int " + toString(commonType.literalValue(nullptr)) + ")");
return false;
}
static const map<Token::Value, char const*> optrans({
{Token::And, " && "},
{Token::Or, " || "},
{Token::BitOr, " lor "},
{Token::BitXor, " lxor "},
{Token::BitAnd, " land "},
{Token::Add, " + "},
{Token::Sub, " - "},
{Token::Mul, " * "},
{Token::Div, " / "},
{Token::Mod, " mod "},
{Token::Equal, " = "},
{Token::NotEqual, " <> "},
{Token::LessThan, " < "},
{Token::GreaterThan, " > "},
{Token::LessThanOrEqual, " <= "},
{Token::GreaterThanOrEqual, " >= "}
});
if (!optrans.count(c_op))
error(_binaryOperation, "Operator not supported.");
add("(");
leftExpression.accept(*this);
add(optrans.at(c_op));
rightExpression.accept(*this);
add(")");
return false;
}
bool Why3Translator::visit(FunctionCall const& _node)
{
if (_node.annotation().isTypeConversion || _node.annotation().isStructConstructorCall)
{
error(_node, "Only ordinary function calls supported.");
return true;
}
FunctionType const& function = dynamic_cast<FunctionType const&>(*_node.expression().annotation().type);
if (function.location() != FunctionType::Location::Internal)
{
error(_node, "Only internal function calls supported.");
return true;
}
if (!_node.names().empty())
{
error(_node, "Function calls with named arguments not supported.");
return true;
}
//@TODO check type conversions
add("(");
_node.expression().accept(*this);
add(" StateUnused");
for (auto const& arg: _node.arguments())
{
add(" ");
arg->accept(*this);
}
add(")");
return false;
}
bool Why3Translator::visit(MemberAccess const& _node)
{
if (
_node.expression().annotation().type->category() == Type::Category::Array &&
_node.memberName() == "length" &&
!_node.annotation().lValueRequested
)
{
add("(of_int ");
_node.expression().accept(*this);
add(".length");
add(")");
}
else
error(_node, "Only read-only length access for arrays supported.");
return false;
}
bool Why3Translator::visit(IndexAccess const& _node)
{
auto baseType = dynamic_cast<ArrayType const*>(_node.baseExpression().annotation().type.get());
if (!baseType)
{
error(_node, "Index access only supported for arrays.");
return true;
}
if (_node.annotation().lValueRequested)
{
error(_node, "Assignment to array elements not supported.");
return true;
}
add("(");
_node.baseExpression().accept(*this);
add("[to_int ");
_node.indexExpression()->accept(*this);
add("]");
add(")");
return false;
}
bool Why3Translator::visit(Identifier const& _identifier)
{
Declaration const* declaration = _identifier.annotation().referencedDeclaration;
if (FunctionDefinition const* functionDef = dynamic_cast<FunctionDefinition const*>(declaration))
add("_" + functionDef->name());
else if (auto variable = dynamic_cast<VariableDeclaration const*>(declaration))
{
if (_identifier.annotation().lValueRequested)
add("_" + variable->name());
else
add("!_" + variable->name());
}
else
error(_identifier, "Not supported.");
return false;
}
bool Why3Translator::visit(Literal const& _literal)
{
TypePointer type = _literal.annotation().type;
switch (type->category())
{
case Type::Category::Bool:
if (type->literalValue(&_literal) == 0)
add("false");
else
add("true");
break;
case Type::Category::IntegerConstant:
add("(of_int " + toString(type->literalValue(&_literal)) + ")");
break;
default:
error(_literal, "Not supported.");
}
return false;
}
void Why3Translator::addSourceFromDocStrings(const DocumentedAnnotation& _annotation)
{
auto why3Range = _annotation.docTags.equal_range("why3");
for (auto i = why3Range.first; i != why3Range.second; ++i)
addLine(i->second.content);
}
