path: root/AST.cpp

/*
    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 2014
 * Solidity abstract syntax tree.
 */

#include <algorithm>
#include <libsolidity/Utils.h>
#include <libsolidity/AST.h>
#include <libsolidity/ASTVisitor.h>
#include <libsolidity/Exceptions.h>
#include <libsolidity/AST_accept.h>

#include <libdevcrypto/SHA3.h>

using namespace std;

namespace dev
{
namespace solidity
{

TypeError ASTNode::createTypeError(string const& _description) const
{
    return TypeError() << errinfo_sourceLocation(getLocation()) << errinfo_comment(_description);
}

TypePointer ContractDefinition::getType(ContractDefinition const* _currentContract) const
{
    return make_shared<TypeType>(make_shared<ContractType>(*this), _currentContract);
}

void ContractDefinition::checkTypeRequirements()
{
    for (ASTPointer<InheritanceSpecifier> const& baseSpecifier: getBaseContracts())
        baseSpecifier->checkTypeRequirements();

    checkIllegalOverrides();

    FunctionDefinition const* constructor = getConstructor();
    if (constructor && !constructor->getReturnParameters().empty())
        BOOST_THROW_EXCEPTION(constructor->getReturnParameterList()->createTypeError(
                                  "Non-empty \"returns\" directive for constructor."));

    for (ASTPointer<ModifierDefinition> const& modifier: getFunctionModifiers())
        modifier->checkTypeRequirements();

    for (ASTPointer<FunctionDefinition> const& function: getDefinedFunctions())
        function->checkTypeRequirements();

    // check for hash collisions in function signatures
    set<FixedHash<4>> hashes;
    for (auto const& hashAndFunction: getInterfaceFunctionList())
    {
        FixedHash<4> const& hash = std::get<0>(hashAndFunction);
        if (hashes.count(hash))
            BOOST_THROW_EXCEPTION(createTypeError(
                                      std::string("Function signature hash collision for ") +
                                      std::get<1>(hashAndFunction)->getCanonicalSignature(std::get<2>(hashAndFunction)->getName())));
        hashes.insert(hash);
    }
}

map<FixedHash<4>, FunctionDescription> ContractDefinition::getInterfaceFunctions() const
{
    auto exportedFunctionList = getInterfaceFunctionList();

    map<FixedHash<4>, FunctionDescription> exportedFunctions;
    for (auto const& it: exportedFunctionList)
        exportedFunctions[std::get<0>(it)] = std::move(FunctionDescription(std::get<1>(it), std::get<2>(it)));

    solAssert(exportedFunctionList.size() == exportedFunctions.size(),
              "Hash collision at Function Definition Hash calculation");

    return exportedFunctions;
}

FunctionDefinition const* ContractDefinition::getConstructor() const
{
    for (ASTPointer<FunctionDefinition> const& f: m_definedFunctions)
        if (f->isConstructor())
            return f.get();
    return nullptr;
}

void ContractDefinition::checkIllegalOverrides() const
{
    // TODO unify this at a later point. for this we need to put the constness and the access specifier
    // into the types
    map<string, FunctionDefinition const*> functions;
    map<string, ModifierDefinition const*> modifiers;

    // We search from derived to base, so the stored item causes the error.
    for (ContractDefinition const* contract: getLinearizedBaseContracts())
    {
        for (ASTPointer<FunctionDefinition> const& function: contract->getDefinedFunctions())
        {
            if (function->isConstructor())
                continue; // constructors can neither be overridden nor override anything
            string const& name = function->getName();
            if (modifiers.count(name))
                BOOST_THROW_EXCEPTION(modifiers[name]->createTypeError("Override changes function to modifier."));
            FunctionDefinition const*& override = functions[name];
            if (!override)
                override = function.get();
            else if (override->isPublic() != function->isPublic() ||
                     override->isDeclaredConst() != function->isDeclaredConst() ||
                     FunctionType(*override) != FunctionType(*function))
                BOOST_THROW_EXCEPTION(override->createTypeError("Override changes extended function signature."));
        }
        for (ASTPointer<ModifierDefinition> const& modifier: contract->getFunctionModifiers())
        {
            string const& name = modifier->getName();
            if (functions.count(name))
                BOOST_THROW_EXCEPTION(functions[name]->createTypeError("Override changes modifier to function."));
            ModifierDefinition const*& override = modifiers[name];
            if (!override)
                override = modifier.get();
            else if (ModifierType(*override) != ModifierType(*modifier))
                BOOST_THROW_EXCEPTION(override->createTypeError("Override changes modifier signature."));
        }
    }
}

vector<tuple<FixedHash<4>, std::shared_ptr<FunctionType const>, Declaration const*>> const& ContractDefinition::getInterfaceFunctionList() const
{
    if (!m_interfaceFunctionList)
    {
        set<string> functionsSeen;
        m_interfaceFunctionList.reset(new vector<tuple<FixedHash<4>, std::shared_ptr<FunctionType const>, Declaration const*>>());
        for (ContractDefinition const* contract: getLinearizedBaseContracts())
        {
            for (ASTPointer<FunctionDefinition> const& f: contract->getDefinedFunctions())
                if (f->isPublic() && !f->isConstructor() && functionsSeen.count(f->getName()) == 0)
                {
                    functionsSeen.insert(f->getName());
                    FixedHash<4> hash(dev::sha3(f->getCanonicalSignature()));
                    m_interfaceFunctionList->push_back(make_tuple(hash, make_shared<FunctionType>(*f), f.get()));
                }

            for (ASTPointer<VariableDeclaration> const& v: contract->getStateVariables())
                if (v->isPublic())
                {
                    FunctionType ftype(*v);
                    functionsSeen.insert(v->getName());
                    FixedHash<4> hash(dev::sha3(ftype.getCanonicalSignature(v->getName())));
                    m_interfaceFunctionList->push_back(make_tuple(hash, make_shared<FunctionType>(*v), v.get()));
                }
        }
    }
    return *m_interfaceFunctionList;
}

void InheritanceSpecifier::checkTypeRequirements()
{
    m_baseName->checkTypeRequirements();
    for (ASTPointer<Expression> const& argument: m_arguments)
        argument->checkTypeRequirements();

    ContractDefinition const* base = dynamic_cast<ContractDefinition const*>(m_baseName->getReferencedDeclaration());
    solAssert(base, "Base contract not available.");
    TypePointers parameterTypes = ContractType(*base).getConstructorType()->getParameterTypes();
    if (parameterTypes.size() != m_arguments.size())
        BOOST_THROW_EXCEPTION(createTypeError("Wrong argument count for constructor call."));
    for (size_t i = 0; i < m_arguments.size(); ++i)
        if (!m_arguments[i]->getType()->isImplicitlyConvertibleTo(*parameterTypes[i]))
            BOOST_THROW_EXCEPTION(createTypeError("Invalid type for argument in constructer call."));
}

TypePointer StructDefinition::getType(ContractDefinition const*) const
{
    return make_shared<TypeType>(make_shared<StructType>(*this));
}

void StructDefinition::checkMemberTypes() const
{
    for (ASTPointer<VariableDeclaration> const& member: getMembers())
        if (!member->getType()->canBeStored())
            BOOST_THROW_EXCEPTION(member->createTypeError("Type cannot be used in struct."));
}

void StructDefinition::checkRecursion() const
{
    set<StructDefinition const*> definitionsSeen;
    vector<StructDefinition const*> queue = {this};
    while (!queue.empty())
    {
        StructDefinition const* def = queue.back();
        queue.pop_back();
        if (definitionsSeen.count(def))
            BOOST_THROW_EXCEPTION(ParserError() << errinfo_sourceLocation(def->getLocation())
                                                << errinfo_comment("Recursive struct definition."));
        definitionsSeen.insert(def);
        for (ASTPointer<VariableDeclaration> const& member: def->getMembers())
            if (member->getType()->getCategory() == Type::Category::STRUCT)
            {
                UserDefinedTypeName const& typeName = dynamic_cast<UserDefinedTypeName const&>(*member->getTypeName());
                queue.push_back(&dynamic_cast<StructDefinition const&>(*typeName.getReferencedDeclaration()));
            }
    }
}

TypePointer FunctionDefinition::getType(ContractDefinition const*) const
{
    return make_shared<FunctionType>(*this);
}

void FunctionDefinition::checkTypeRequirements()
{
    for (ASTPointer<VariableDeclaration> const& var: getParameters() + getReturnParameters())
        if (!var->getType()->canLiveOutsideStorage())
            BOOST_THROW_EXCEPTION(var->createTypeError("Type is required to live outside storage."));
    for (ASTPointer<ModifierInvocation> const& modifier: m_functionModifiers)
        modifier->checkTypeRequirements();

    m_body->checkTypeRequirements();
}

string FunctionDefinition::getCanonicalSignature() const
{
    return FunctionType(*this).getCanonicalSignature(getName());
}

Declaration::LValueType VariableDeclaration::getLValueType() const
{
    if (dynamic_cast<FunctionDefinition const*>(getScope()) || dynamic_cast<ModifierDefinition const*>(getScope()))
        return Declaration::LValueType::LOCAL;
    else
        return Declaration::LValueType::STORAGE;
}

TypePointer ModifierDefinition::getType(ContractDefinition const*) const
{
    return make_shared<ModifierType>(*this);
}

void ModifierDefinition::checkTypeRequirements()
{
    m_body->checkTypeRequirements();
}

void ModifierInvocation::checkTypeRequirements()
{
    m_modifierName->checkTypeRequirements();
    for (ASTPointer<Expression> const& argument: m_arguments)
        argument->checkTypeRequirements();

    ModifierDefinition const* modifier = dynamic_cast<ModifierDefinition const*>(m_modifierName->getReferencedDeclaration());
    solAssert(modifier, "Function modifier not found.");
    vector<ASTPointer<VariableDeclaration>> const& parameters = modifier->getParameters();
    if (parameters.size() != m_arguments.size())
        BOOST_THROW_EXCEPTION(createTypeError("Wrong argument count for modifier invocation."));
    for (size_t i = 0; i < m_arguments.size(); ++i)
        if (!m_arguments[i]->getType()->isImplicitlyConvertibleTo(*parameters[i]->getType()))
            BOOST_THROW_EXCEPTION(createTypeError("Invalid type for argument in modifier invocation."));
}

void Block::checkTypeRequirements()
{
    for (shared_ptr<Statement> const& statement: m_statements)
        statement->checkTypeRequirements();
}

void IfStatement::checkTypeRequirements()
{
    m_condition->expectType(BoolType());
    m_trueBody->checkTypeRequirements();
    if (m_falseBody)
        m_falseBody->checkTypeRequirements();
}

void WhileStatement::checkTypeRequirements()
{
    m_condition->expectType(BoolType());
    m_body->checkTypeRequirements();
}

void ForStatement::checkTypeRequirements()
{
    if (m_initExpression)
        m_initExpression->checkTypeRequirements();
    if (m_condExpression)
        m_condExpression->expectType(BoolType());
    if (m_loopExpression)
        m_loopExpression->checkTypeRequirements();
    m_body->checkTypeRequirements();
}

void Return::checkTypeRequirements()
{
    if (!m_expression)
        return;
    if (!m_returnParameters)
        BOOST_THROW_EXCEPTION(createTypeError("Return arguments not allowed."));
    if (m_returnParameters->getParameters().size() != 1)
        BOOST_THROW_EXCEPTION(createTypeError("Different number of arguments in return statement "
                                              "than in returns declaration."));
    // this could later be changed such that the paramaters type is an anonymous struct type,
    // but for now, we only allow one return parameter
    m_expression->expectType(*m_returnParameters->getParameters().front()->getType());
}

void VariableDefinition::checkTypeRequirements()
{
    // Variables can be declared without type (with "var"), in which case the first assignment
    // sets the type.
    // Note that assignments before the first declaration are legal because of the special scoping
    // rules inherited from JavaScript.
    if (m_value)
    {
        if (m_variable->getType())
            m_value->expectType(*m_variable->getType());
        else
        {
            // no type declared and no previous assignment, infer the type
            m_value->checkTypeRequirements();
            TypePointer type = m_value->getType();
            if (type->getCategory() == Type::Category::INTEGER_CONSTANT)
            {
                auto intType = dynamic_pointer_cast<IntegerConstantType const>(type)->getIntegerType();
                if (!intType)
                    BOOST_THROW_EXCEPTION(m_value->createTypeError("Invalid integer constant " + type->toString()));
                type = intType;
            }
            m_variable->setType(type);
        }
    }
}

void Assignment::checkTypeRequirements()
{
    m_leftHandSide->checkTypeRequirements();
    m_leftHandSide->requireLValue();
    //@todo later, assignments to structs might be possible, but not to mappings
    if (!m_leftHandSide->getType()->isValueType() && !m_leftHandSide->isLocalLValue())
        BOOST_THROW_EXCEPTION(createTypeError("Assignment to non-local non-value lvalue."));
    m_type = m_leftHandSide->getType();
    if (m_assigmentOperator == Token::ASSIGN)
        m_rightHandSide->expectType(*m_type);
    else
    {
        // compound assignment
        m_rightHandSide->checkTypeRequirements();
        TypePointer resultType = m_type->binaryOperatorResult(Token::AssignmentToBinaryOp(m_assigmentOperator),
                                                              m_rightHandSide->getType());
        if (!resultType || *resultType != *m_type)
            BOOST_THROW_EXCEPTION(createTypeError("Operator " + string(Token::toString(m_assigmentOperator)) +
                                                  " not compatible with types " +
                                                  m_type->toString() + " and " +
                                                  m_rightHandSide->getType()->toString()));
    }
}

void ExpressionStatement::checkTypeRequirements()
{
    m_expression->checkTypeRequirements();
    if (m_expression->getType()->getCategory() == Type::Category::INTEGER_CONSTANT)
        if (!dynamic_pointer_cast<IntegerConstantType const>(m_expression->getType())->getIntegerType())
            BOOST_THROW_EXCEPTION(m_expression->createTypeError("Invalid integer constant."));
}

void Expression::expectType(Type const& _expectedType)
{
    checkTypeRequirements();
    Type const& type = *getType();
    if (!type.isImplicitlyConvertibleTo(_expectedType))
        BOOST_THROW_EXCEPTION(createTypeError("Type " + type.toString() +
                                              " not implicitly convertible to expected type "
                                              + _expectedType.toString() + "."));
}

void Expression::requireLValue()
{
    if (!isLValue())
        BOOST_THROW_EXCEPTION(createTypeError("Expression has to be an lvalue."));
    m_lvalueRequested = true;
}

void UnaryOperation::checkTypeRequirements()
{
    // INC, DEC, ADD, SUB, NOT, BIT_NOT, DELETE
    m_subExpression->checkTypeRequirements();
    if (m_operator == Token::Value::INC || m_operator == Token::Value::DEC || m_operator == Token::Value::DELETE)
        m_subExpression->requireLValue();
    m_type = m_subExpression->getType()->unaryOperatorResult(m_operator);
    if (!m_type)
        BOOST_THROW_EXCEPTION(createTypeError("Unary operator not compatible with type."));
}

void BinaryOperation::checkTypeRequirements()
{
    m_left->checkTypeRequirements();
    m_right->checkTypeRequirements();
    m_commonType = m_left->getType()->binaryOperatorResult(m_operator, m_right->getType());
    if (!m_commonType)
        BOOST_THROW_EXCEPTION(createTypeError("Operator " + string(Token::toString(m_operator)) +
                                              " not compatible with types " +
                                              m_left->getType()->toString() + " and " +
                                              m_right->getType()->toString()));
    m_type = Token::isCompareOp(m_operator) ? make_shared<BoolType>() : m_commonType;
}

void FunctionCall::checkTypeRequirements()
{
    m_expression->checkTypeRequirements();
    for (ASTPointer<Expression> const& argument: m_arguments)
        argument->checkTypeRequirements();

    Type const* expressionType = m_expression->getType().get();
    if (isTypeConversion())
    {
        TypeType const& type = dynamic_cast<TypeType const&>(*expressionType);
        //@todo for structs, we have to check the number of arguments to be equal to the
        // number of non-mapping members
        if (m_arguments.size() != 1)
            BOOST_THROW_EXCEPTION(createTypeError("More than one argument for explicit type conversion."));
        if (!m_arguments.front()->getType()->isExplicitlyConvertibleTo(*type.getActualType()))
            BOOST_THROW_EXCEPTION(createTypeError("Explicit type conversion not allowed."));
        m_type = type.getActualType();
    }
    else if (FunctionType const* functionType = dynamic_cast<FunctionType const*>(expressionType))
    {
        //@todo would be nice to create a struct type from the arguments
        // and then ask if that is implicitly convertible to the struct represented by the
        // function parameters
        TypePointers const& parameterTypes = functionType->getParameterTypes();
        if (parameterTypes.size() != m_arguments.size())
            BOOST_THROW_EXCEPTION(createTypeError("Wrong argument count for function call."));
        for (size_t i = 0; i < m_arguments.size(); ++i)
            if (!m_arguments[i]->getType()->isImplicitlyConvertibleTo(*parameterTypes[i]))
                BOOST_THROW_EXCEPTION(createTypeError("Invalid type for argument in function call."));
        // @todo actually the return type should be an anonymous struct,
        // but we change it to the type of the first return value until we have structs
        if (functionType->getReturnParameterTypes().empty())
            m_type = make_shared<VoidType>();
        else
            m_type = functionType->getReturnParameterTypes().front();
    }
    else
        BOOST_THROW_EXCEPTION(createTypeError("Type is not callable."));
}

bool FunctionCall::isTypeConversion() const
{
    return m_expression->getType()->getCategory() == Type::Category::TYPE;
}

void NewExpression::checkTypeRequirements()
{
    m_contractName->checkTypeRequirements();
    m_contract = dynamic_cast<ContractDefinition const*>(m_contractName->getReferencedDeclaration());
    if (!m_contract)
        BOOST_THROW_EXCEPTION(createTypeError("Identifier is not a contract."));
    shared_ptr<ContractType const> contractType = make_shared<ContractType>(*m_contract);
    TypePointers const& parameterTypes = contractType->getConstructorType()->getParameterTypes();
    m_type = make_shared<FunctionType>(parameterTypes, TypePointers{contractType},
                                       FunctionType::Location::CREATION);
}

void MemberAccess::checkTypeRequirements()
{
    m_expression->checkTypeRequirements();
    Type const& type = *m_expression->getType();
    m_type = type.getMemberType(*m_memberName);
    if (!m_type)
        BOOST_THROW_EXCEPTION(createTypeError("Member \"" + *m_memberName + "\" not found or not "
                                              "visible in " + type.toString()));
    //@todo later, this will not always be STORAGE
    m_lvalue = type.getCategory() == Type::Category::STRUCT ? Declaration::LValueType::STORAGE : Declaration::LValueType::NONE;
}

void IndexAccess::checkTypeRequirements()
{
    m_base->checkTypeRequirements();
    if (m_base->getType()->getCategory() != Type::Category::MAPPING)
        BOOST_THROW_EXCEPTION(m_base->createTypeError("Indexed expression has to be a mapping (is " +
                                                      m_base->getType()->toString() + ")"));
    MappingType const& type = dynamic_cast<MappingType const&>(*m_base->getType());
    m_index->expectType(*type.getKeyType());
    m_type = type.getValueType();
    m_lvalue = Declaration::LValueType::STORAGE;
}

void Identifier::checkTypeRequirements()
{
    solAssert(m_referencedDeclaration, "Identifier not resolved.");

    m_lvalue = m_referencedDeclaration->getLValueType();
    m_type = m_referencedDeclaration->getType(m_currentContract);
    if (!m_type)
        BOOST_THROW_EXCEPTION(createTypeError("Declaration referenced before type could be determined."));
}

void ElementaryTypeNameExpression::checkTypeRequirements()
{
    m_type = make_shared<TypeType>(Type::fromElementaryTypeName(m_typeToken));
}

void Literal::checkTypeRequirements()
{
    m_type = Type::forLiteral(*this);
    if (!m_type)
        BOOST_THROW_EXCEPTION(createTypeError("Invalid literal value."));
}

std::string ParamDescription::getName() const
{
    return m_description.first;
}

std::string ParamDescription::getType() const
{
    return m_description.second;
}

ASTPointer<ASTString> FunctionDescription::getDocumentation() const
{
    auto function = dynamic_cast<FunctionDefinition const*>(m_description.second);
    if (function)
        return function->getDocumentation();

    return ASTPointer<ASTString>();
}

string FunctionDescription::getSignature() const
{
    return m_description.first->getCanonicalSignature(m_description.second->getName());
}

string FunctionDescription::getName() const
{
    return m_description.second->getName();
}

bool FunctionDescription::isConstant() const
{
    auto function = dynamic_cast<FunctionDefinition const*>(m_description.second);
    if (function)
        return function->isDeclaredConst();

    return true;
}

vector<ParamDescription> const FunctionDescription::getParameters() const
{
    auto function = dynamic_cast<FunctionDefinition const*>(m_description.second);
    if (function)
    {
        vector<ParamDescription> paramsDescription;
        for (auto const& param: function->getReturnParameters())
            paramsDescription.push_back(ParamDescription(param->getName(), param->getType()->toString()));

        return paramsDescription;
    }

    // else for now let's assume no parameters to accessors
    // LTODO: fix this for mapping types
    return {};
}

vector<ParamDescription> const FunctionDescription::getReturnParameters() const
{
    auto function = dynamic_cast<FunctionDefinition const*>(m_description.second);
    if (function)
    {
        vector<ParamDescription> paramsDescription;
        for (auto const& param: function->getParameters())
            paramsDescription.push_back(ParamDescription(param->getName(), param->getType()->toString()));

        return paramsDescription;
    }

    auto vardecl = dynamic_cast<VariableDeclaration const*>(m_description.second);
    return {ParamDescription(vardecl->getName(), vardecl->getType()->toString())};
}

Declaration const* FunctionDescription::getDeclaration() const
{
    return m_description.second;
}

VariableDeclaration const* FunctionDescription::getVariableDeclaration() const
{
    return dynamic_cast<VariableDeclaration const*>(m_description.second);
}

FunctionDefinition const* FunctionDescription::getFunctionDefinition() const
{
    return dynamic_cast<FunctionDefinition const*>(m_description.second);
}

shared_ptr<FunctionType const> FunctionDescription::getFunctionTypeShared() const
{
    return m_description.first;
}


FunctionType const* FunctionDescription::getFunctionType() const
{
    return m_description.first.get();
}


}
}