path: root/libsolidity/analysis/NameAndTypeResolver.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 2014
 * Parser part that determines the declarations corresponding to names and the types of expressions.
 */

#include <libsolidity/analysis/NameAndTypeResolver.h>

#include <libsolidity/ast/AST.h>
#include <libsolidity/analysis/TypeChecker.h>
#include <libsolidity/interface/ErrorReporter.h>
#include <libdevcore/StringUtils.h>

#include <boost/algorithm/string.hpp>

using namespace std;

namespace dev
{
namespace solidity
{

NameAndTypeResolver::NameAndTypeResolver(
    vector<Declaration const*> const& _globals,
    map<ASTNode const*, shared_ptr<DeclarationContainer>>& _scopes,
    ErrorReporter& _errorReporter
) :
    m_scopes(_scopes),
    m_errorReporter(_errorReporter)
{
    if (!m_scopes[nullptr])
        m_scopes[nullptr].reset(new DeclarationContainer());
    for (Declaration const* declaration: _globals)
    {
        solAssert(m_scopes[nullptr]->registerDeclaration(*declaration), "Unable to register global declaration.");
    }
}

bool NameAndTypeResolver::registerDeclarations(SourceUnit& _sourceUnit, ASTNode const* _currentScope)
{
    // The helper registers all declarations in m_scopes as a side-effect of its construction.
    try
    {
        DeclarationRegistrationHelper registrar(m_scopes, _sourceUnit, m_errorReporter, _currentScope);
    }
    catch (FatalError const&)
    {
        if (m_errorReporter.errors().empty())
            throw; // Something is weird here, rather throw again.
        return false;
    }
    return true;
}

bool NameAndTypeResolver::performImports(SourceUnit& _sourceUnit, map<string, SourceUnit const*> const& _sourceUnits)
{
    DeclarationContainer& target = *m_scopes.at(&_sourceUnit);
    bool error = false;
    for (auto const& node: _sourceUnit.nodes())
        if (auto imp = dynamic_cast<ImportDirective const*>(node.get()))
        {
            string const& path = imp->annotation().absolutePath;
            if (!_sourceUnits.count(path))
            {
                m_errorReporter.declarationError(
                    imp->location(),
                    "Import \"" + path + "\" (referenced as \"" + imp->path() + "\") not found."
                );
                error = true;
                continue;
            }
            auto scope = m_scopes.find(_sourceUnits.at(path));
            solAssert(scope != end(m_scopes), "");
            if (!imp->symbolAliases().empty())
                for (auto const& alias: imp->symbolAliases())
                {
                    auto declarations = scope->second->resolveName(alias.first->name(), false);
                    if (declarations.empty())
                    {
                        m_errorReporter.declarationError(
                            imp->location(),
                            "Declaration \"" +
                            alias.first->name() +
                            "\" not found in \"" +
                            path +
                            "\" (referenced as \"" +
                            imp->path() +
                            "\")."
                        );
                        error = true;
                    }
                    else
                        for (Declaration const* declaration: declarations)
                            if (!DeclarationRegistrationHelper::registerDeclaration(
                                target, *declaration, alias.second.get(), &imp->location(), true, false, m_errorReporter
                            ))
                                error = true;
                }
            else if (imp->name().empty())
                for (auto const& nameAndDeclaration: scope->second->declarations())
                    for (auto const& declaration: nameAndDeclaration.second)
                        if (!DeclarationRegistrationHelper::registerDeclaration(
                            target, *declaration, &nameAndDeclaration.first, &imp->location(), true, false, m_errorReporter
                        ))
                            error =  true;
        }
    return !error;
}

bool NameAndTypeResolver::resolveNamesAndTypes(ASTNode& _node, bool _resolveInsideCode)
{
    try
    {
        return resolveNamesAndTypesInternal(_node, _resolveInsideCode);
    }
    catch (FatalError const&)
    {
        if (m_errorReporter.errors().empty())
            throw; // Something is weird here, rather throw again.
        return false;
    }
}

bool NameAndTypeResolver::updateDeclaration(Declaration const& _declaration)
{
    try
    {
        m_scopes[nullptr]->registerDeclaration(_declaration, nullptr, false, true);
        solAssert(_declaration.scope() == nullptr, "Updated declaration outside global scope.");
    }
    catch (FatalError const&)
    {
        if (m_errorReporter.errors().empty())
            throw; // Something is weird here, rather throw again.
        return false;
    }
    return true;
}

void NameAndTypeResolver::activateVariable(string const& _name)
{
    solAssert(m_currentScope, "");
    // Scoped local variables are invisible before activation.
    // When a local variable is activated, its name is removed
    // from a scope's invisible variables.
    // This is used to avoid activation of variables of same name
    // in the same scope (an error is returned).
    if (m_currentScope->isInvisible(_name))
        m_currentScope->activateVariable(_name);
}

vector<Declaration const*> NameAndTypeResolver::resolveName(ASTString const& _name, ASTNode const* _scope) const
{
    auto iterator = m_scopes.find(_scope);
    if (iterator == end(m_scopes))
        return vector<Declaration const*>({});
    return iterator->second->resolveName(_name, false);
}

vector<Declaration const*> NameAndTypeResolver::nameFromCurrentScope(ASTString const& _name, bool _includeInvisibles) const
{
    return m_currentScope->resolveName(_name, true, _includeInvisibles);
}

Declaration const* NameAndTypeResolver::pathFromCurrentScope(vector<ASTString> const& _path) const
{
    solAssert(!_path.empty(), "");
    vector<Declaration const*> candidates = m_currentScope->resolveName(_path.front(), true);
    for (size_t i = 1; i < _path.size() && candidates.size() == 1; i++)
    {
        if (!m_scopes.count(candidates.front()))
            return nullptr;
        candidates = m_scopes.at(candidates.front())->resolveName(_path[i], false);
    }
    if (candidates.size() == 1)
        return candidates.front();
    else
        return nullptr;
}

vector<Declaration const*> NameAndTypeResolver::cleanedDeclarations(
        Identifier const& _identifier,
        vector<Declaration const*> const& _declarations
)
{
    solAssert(_declarations.size() > 1, "");
    vector<Declaration const*> uniqueFunctions;

    for (Declaration const* declaration: _declarations)
    {
        solAssert(declaration, "");
        // the declaration is functionDefinition, eventDefinition or a VariableDeclaration while declarations > 1
        solAssert(
            dynamic_cast<FunctionDefinition const*>(declaration) ||
            dynamic_cast<EventDefinition const*>(declaration) ||
            dynamic_cast<VariableDeclaration const*>(declaration) ||
            dynamic_cast<MagicVariableDeclaration const*>(declaration),
            "Found overloading involving something not a function, event or a (magic) variable."
        );

        FunctionTypePointer functionType { declaration->functionType(false) };
        if (!functionType)
            functionType = declaration->functionType(true);
        solAssert(functionType, "Failed to determine the function type of the overloaded.");

        for (auto parameter: functionType->parameterTypes() + functionType->returnParameterTypes())
            if (!parameter)
                m_errorReporter.fatalDeclarationError(_identifier.location(), "Function type can not be used in this context.");

        if (uniqueFunctions.end() == find_if(
            uniqueFunctions.begin(),
            uniqueFunctions.end(),
            [&](Declaration const* d)
            {
                shared_ptr<FunctionType const> newFunctionType { d->functionType(false) };
                if (!newFunctionType)
                    newFunctionType = d->functionType(true);
                return newFunctionType && functionType->hasEqualParameterTypes(*newFunctionType);
            }
        ))
            uniqueFunctions.push_back(declaration);
    }
    return uniqueFunctions;
}

void NameAndTypeResolver::warnVariablesNamedLikeInstructions()
{
    for (auto const& instruction: c_instructions)
    {
        string const instructionName{boost::algorithm::to_lower_copy(instruction.first)};
        auto declarations = nameFromCurrentScope(instructionName, true);
        for (Declaration const* const declaration: declarations)
        {
            solAssert(!!declaration, "");
            if (dynamic_cast<MagicVariableDeclaration const* const>(declaration))
                // Don't warn the user for what the user did not.
                continue;
            m_errorReporter.warning(
                declaration->location(),
                "Variable is shadowed in inline assembly by an instruction of the same name"
            );
        }
    }
}

void NameAndTypeResolver::setScope(ASTNode const* _node)
{
    m_currentScope = m_scopes[_node].get();
}

bool NameAndTypeResolver::resolveNamesAndTypesInternal(ASTNode& _node, bool _resolveInsideCode)
{
    if (ContractDefinition* contract = dynamic_cast<ContractDefinition*>(&_node))
    {
        bool success = true;
        setScope(contract->scope());
        solAssert(!!m_currentScope, "");

        for (ASTPointer<InheritanceSpecifier> const& baseContract: contract->baseContracts())
            if (!resolveNamesAndTypes(*baseContract, true))
                success = false;

        setScope(contract);

        if (success)
        {
            linearizeBaseContracts(*contract);
            vector<ContractDefinition const*> properBases(
                ++contract->annotation().linearizedBaseContracts.begin(),
                contract->annotation().linearizedBaseContracts.end()
            );

            for (ContractDefinition const* base: properBases)
                importInheritedScope(*base);
        }

        // these can contain code, only resolve parameters for now
        for (ASTPointer<ASTNode> const& node: contract->subNodes())
        {
            setScope(contract);
            if (!resolveNamesAndTypes(*node, false))
            {
                success = false;
                break;
            }
        }

        if (!success)
            return false;

        if (!_resolveInsideCode)
            return success;

        setScope(contract);

        // now resolve references inside the code
        for (ASTPointer<ASTNode> const& node: contract->subNodes())
        {
            setScope(contract);
            if (!resolveNamesAndTypes(*node, true))
                success = false;
        }
        return success;
    }
    else
    {
        if (m_scopes.count(&_node))
            setScope(&_node);
        return ReferencesResolver(m_errorReporter, *this, _resolveInsideCode).resolve(_node);
    }
}

void NameAndTypeResolver::importInheritedScope(ContractDefinition const& _base)
{
    auto iterator = m_scopes.find(&_base);
    solAssert(iterator != end(m_scopes), "");
    for (auto const& nameAndDeclaration: iterator->second->declarations())
        for (auto const& declaration: nameAndDeclaration.second)
            // Import if it was declared in the base, is not the constructor and is visible in derived classes
            if (declaration->scope() == &_base && declaration->isVisibleInDerivedContracts())
                if (!m_currentScope->registerDeclaration(*declaration))
                {
                    SourceLocation firstDeclarationLocation;
                    SourceLocation secondDeclarationLocation;
                    Declaration const* conflictingDeclaration = m_currentScope->conflictingDeclaration(*declaration);
                    solAssert(conflictingDeclaration, "");

                    // Usual shadowing is not an error
                    if (dynamic_cast<VariableDeclaration const*>(declaration) && dynamic_cast<VariableDeclaration const*>(conflictingDeclaration))
                        continue;

                    // Usual shadowing is not an error
                    if (dynamic_cast<ModifierDefinition const*>(declaration) && dynamic_cast<ModifierDefinition const*>(conflictingDeclaration))
                        continue;

                    if (declaration->location().start < conflictingDeclaration->location().start)
                    {
                        firstDeclarationLocation = declaration->location();
                        secondDeclarationLocation = conflictingDeclaration->location();
                    }
                    else
                    {
                        firstDeclarationLocation = conflictingDeclaration->location();
                        secondDeclarationLocation = declaration->location();
                    }

                    m_errorReporter.declarationError(
                        secondDeclarationLocation,
                        SecondarySourceLocation().append("The previous declaration is here:", firstDeclarationLocation),
                        "Identifier already declared."
                    );
                }
}

void NameAndTypeResolver::linearizeBaseContracts(ContractDefinition& _contract)
{
    // order in the lists is from derived to base
    // list of lists to linearize, the last element is the list of direct bases
    list<list<ContractDefinition const*>> input(1, list<ContractDefinition const*>{});
    for (ASTPointer<InheritanceSpecifier> const& baseSpecifier: _contract.baseContracts())
    {
        UserDefinedTypeName const& baseName = baseSpecifier->name();
        auto base = dynamic_cast<ContractDefinition const*>(baseName.annotation().referencedDeclaration);
        if (!base)
            m_errorReporter.fatalTypeError(baseName.location(), "Contract expected.");
        // "push_front" has the effect that bases mentioned later can overwrite members of bases
        // mentioned earlier
        input.back().push_front(base);
        vector<ContractDefinition const*> const& basesBases = base->annotation().linearizedBaseContracts;
        if (basesBases.empty())
            m_errorReporter.fatalTypeError(baseName.location(), "Definition of base has to precede definition of derived contract");
        input.push_front(list<ContractDefinition const*>(basesBases.begin(), basesBases.end()));
    }
    input.back().push_front(&_contract);
    vector<ContractDefinition const*> result = cThreeMerge(input);
    if (result.empty())
        m_errorReporter.fatalTypeError(_contract.location(), "Linearization of inheritance graph impossible");
    _contract.annotation().linearizedBaseContracts = result;
    _contract.annotation().contractDependencies.insert(result.begin() + 1, result.end());
}

template <class _T>
vector<_T const*> NameAndTypeResolver::cThreeMerge(list<list<_T const*>>& _toMerge)
{
    // returns true iff _candidate appears only as last element of the lists
    auto appearsOnlyAtHead = [&](_T const* _candidate) -> bool
    {
        for (list<_T const*> const& bases: _toMerge)
        {
            solAssert(!bases.empty(), "");
            if (find(++bases.begin(), bases.end(), _candidate) != bases.end())
                return false;
        }
        return true;
    };
    // returns the next candidate to append to the linearized list or nullptr on failure
    auto nextCandidate = [&]() -> _T const*
    {
        for (list<_T const*> const& bases: _toMerge)
        {
            solAssert(!bases.empty(), "");
            if (appearsOnlyAtHead(bases.front()))
                return bases.front();
        }
        return nullptr;
    };
    // removes the given contract from all lists
    auto removeCandidate = [&](_T const* _candidate)
    {
        for (auto it = _toMerge.begin(); it != _toMerge.end();)
        {
            it->remove(_candidate);
            if (it->empty())
                it = _toMerge.erase(it);
            else
                ++it;
        }
    };

    _toMerge.remove_if([](list<_T const*> const& _bases) { return _bases.empty(); });
    vector<_T const*> result;
    while (!_toMerge.empty())
    {
        _T const* candidate = nextCandidate();
        if (!candidate)
            return vector<_T const*>();
        result.push_back(candidate);
        removeCandidate(candidate);
    }
    return result;
}

string NameAndTypeResolver::similarNameSuggestions(ASTString const& _name) const
{
    return quotedAlternativesList(m_currentScope->similarNames(_name));
}

DeclarationRegistrationHelper::DeclarationRegistrationHelper(
    map<ASTNode const*, shared_ptr<DeclarationContainer>>& _scopes,
    ASTNode& _astRoot,
    ErrorReporter& _errorReporter,
    ASTNode const* _currentScope
):
    m_scopes(_scopes),
    m_currentScope(_currentScope),
    m_errorReporter(_errorReporter)
{
    _astRoot.accept(*this);
    solAssert(m_currentScope == _currentScope, "Scopes not correctly closed.");
}

bool DeclarationRegistrationHelper::registerDeclaration(
    DeclarationContainer& _container,
    Declaration const& _declaration,
    string const* _name,
    SourceLocation const* _errorLocation,
    bool _warnOnShadow,
    bool _inactive,
    ErrorReporter& _errorReporter
)
{
    if (!_errorLocation)
        _errorLocation = &_declaration.location();

    string name = _name ? *_name : _declaration.name();
    Declaration const* shadowedDeclaration = nullptr;
    if (_warnOnShadow && !name.empty() && _container.enclosingContainer())
        for (auto const* decl: _container.enclosingContainer()->resolveName(name, true, true))
            shadowedDeclaration = decl;

    // We use "invisible" for both inactive variables in blocks and for members invisible in contracts.
    // They cannot both be true at the same time.
    solAssert(!(_inactive && !_declaration.isVisibleInContract()), "");
    if (!_container.registerDeclaration(_declaration, _name, !_declaration.isVisibleInContract() || _inactive))
    {
        SourceLocation firstDeclarationLocation;
        SourceLocation secondDeclarationLocation;
        Declaration const* conflictingDeclaration = _container.conflictingDeclaration(_declaration, _name);
        solAssert(conflictingDeclaration, "");
        bool const comparable =
            _errorLocation->sourceName &&
            conflictingDeclaration->location().sourceName &&
            *_errorLocation->sourceName == *conflictingDeclaration->location().sourceName;
        if (comparable && _errorLocation->start < conflictingDeclaration->location().start)
        {
            firstDeclarationLocation = *_errorLocation;
            secondDeclarationLocation = conflictingDeclaration->location();
        }
        else
        {
            firstDeclarationLocation = conflictingDeclaration->location();
            secondDeclarationLocation = *_errorLocation;
        }

        _errorReporter.declarationError(
            secondDeclarationLocation,
            SecondarySourceLocation().append("The previous declaration is here:", firstDeclarationLocation),
            "Identifier already declared."
        );
        return false;
    }
    else if (shadowedDeclaration)
    {
        if (dynamic_cast<MagicVariableDeclaration const*>(shadowedDeclaration))
            _errorReporter.warning(
                _declaration.location(),
                "This declaration shadows a builtin symbol."
            );
        else
        {
            auto shadowedLocation = shadowedDeclaration->location();
            _errorReporter.warning(
                _declaration.location(),
                "This declaration shadows an existing declaration.",
                SecondarySourceLocation().append("The shadowed declaration is here:", shadowedLocation)
            );
        }
    }
    return true;
}

bool DeclarationRegistrationHelper::visit(SourceUnit& _sourceUnit)
{
    if (!m_scopes[&_sourceUnit])
        // By importing, it is possible that the container already exists.
        m_scopes[&_sourceUnit].reset(new DeclarationContainer(m_currentScope, m_scopes[m_currentScope].get()));
    m_currentScope = &_sourceUnit;
    return true;
}

void DeclarationRegistrationHelper::endVisit(SourceUnit& _sourceUnit)
{
    _sourceUnit.annotation().exportedSymbols = m_scopes[&_sourceUnit]->declarations();
    closeCurrentScope();
}

bool DeclarationRegistrationHelper::visit(ImportDirective& _import)
{
    SourceUnit const* importee = _import.annotation().sourceUnit;
    solAssert(!!importee, "");
    if (!m_scopes[importee])
        m_scopes[importee].reset(new DeclarationContainer(nullptr, m_scopes[nullptr].get()));
    m_scopes[&_import] = m_scopes[importee];
    registerDeclaration(_import, false);
    return true;
}

bool DeclarationRegistrationHelper::visit(ContractDefinition& _contract)
{
    registerDeclaration(_contract, true);
    _contract.annotation().canonicalName = currentCanonicalName();
    return true;
}

void DeclarationRegistrationHelper::endVisit(ContractDefinition&)
{
    closeCurrentScope();
}

bool DeclarationRegistrationHelper::visit(StructDefinition& _struct)
{
    registerDeclaration(_struct, true);
    _struct.annotation().canonicalName = currentCanonicalName();
    return true;
}

void DeclarationRegistrationHelper::endVisit(StructDefinition&)
{
    closeCurrentScope();
}

bool DeclarationRegistrationHelper::visit(EnumDefinition& _enum)
{
    registerDeclaration(_enum, true);
    _enum.annotation().canonicalName = currentCanonicalName();
    return true;
}

void DeclarationRegistrationHelper::endVisit(EnumDefinition&)
{
    closeCurrentScope();
}

bool DeclarationRegistrationHelper::visit(EnumValue& _value)
{
    registerDeclaration(_value, false);
    return true;
}

bool DeclarationRegistrationHelper::visit(FunctionDefinition& _function)
{
    registerDeclaration(_function, true);
    m_currentFunction = &_function;
    return true;
}

void DeclarationRegistrationHelper::endVisit(FunctionDefinition&)
{
    m_currentFunction = nullptr;
    closeCurrentScope();
}

bool DeclarationRegistrationHelper::visit(ModifierDefinition& _modifier)
{
    registerDeclaration(_modifier, true);
    m_currentFunction = &_modifier;
    return true;
}

void DeclarationRegistrationHelper::endVisit(ModifierDefinition&)
{
    m_currentFunction = nullptr;
    closeCurrentScope();
}

bool DeclarationRegistrationHelper::visit(Block& _block)
{
    _block.setScope(m_currentScope);
    enterNewSubScope(_block);
    return true;
}

void DeclarationRegistrationHelper::endVisit(Block&)
{
    closeCurrentScope();
}

bool DeclarationRegistrationHelper::visit(ForStatement& _for)
{
    _for.setScope(m_currentScope);
    enterNewSubScope(_for);
    return true;
}

void DeclarationRegistrationHelper::endVisit(ForStatement&)
{
    closeCurrentScope();
}

void DeclarationRegistrationHelper::endVisit(VariableDeclarationStatement& _variableDeclarationStatement)
{
    // Register the local variables with the function
    // This does not fit here perfectly, but it saves us another AST visit.
    solAssert(m_currentFunction, "Variable declaration without function.");
    for (ASTPointer<VariableDeclaration> const& var: _variableDeclarationStatement.declarations())
        if (var)
            m_currentFunction->addLocalVariable(*var);
}

bool DeclarationRegistrationHelper::visit(VariableDeclaration& _declaration)
{
    registerDeclaration(_declaration, false);
    return true;
}

bool DeclarationRegistrationHelper::visit(EventDefinition& _event)
{
    registerDeclaration(_event, true);
    return true;
}

void DeclarationRegistrationHelper::endVisit(EventDefinition&)
{
    closeCurrentScope();
}

void DeclarationRegistrationHelper::enterNewSubScope(ASTNode& _subScope)
{
    map<ASTNode const*, shared_ptr<DeclarationContainer>>::iterator iter;
    bool newlyAdded;
    shared_ptr<DeclarationContainer> container(new DeclarationContainer(m_currentScope, m_scopes[m_currentScope].get()));
    tie(iter, newlyAdded) = m_scopes.emplace(&_subScope, move(container));
    solAssert(newlyAdded, "Unable to add new scope.");
    m_currentScope = &_subScope;
}

void DeclarationRegistrationHelper::closeCurrentScope()
{
    solAssert(m_currentScope && m_scopes.count(m_currentScope), "Closed non-existing scope.");
    m_currentScope = m_scopes[m_currentScope]->enclosingNode();
}

void DeclarationRegistrationHelper::registerDeclaration(Declaration& _declaration, bool _opensScope)
{
    solAssert(m_currentScope && m_scopes.count(m_currentScope), "No current scope.");

    bool warnAboutShadowing = true;
    // Do not warn about shadowing for structs and enums because their members are
    // not accessible without prefixes. Also do not warn about event parameters
    // because they don't participate in any proper scope.
    if (
        dynamic_cast<StructDefinition const*>(m_currentScope) ||
        dynamic_cast<EnumDefinition const*>(m_currentScope) ||
        dynamic_cast<EventDefinition const*>(m_currentScope)
    )
        warnAboutShadowing = false;

    // Register declaration as inactive if we are in block scope.
    bool inactive =
        (dynamic_cast<Block const*>(m_currentScope) || dynamic_cast<ForStatement const*>(m_currentScope));

    registerDeclaration(*m_scopes[m_currentScope], _declaration, nullptr, nullptr, warnAboutShadowing, inactive, m_errorReporter);

    _declaration.setScope(m_currentScope);
    if (_opensScope)
        enterNewSubScope(_declaration);
}

string DeclarationRegistrationHelper::currentCanonicalName() const
{
    string ret;
    for (
        ASTNode const* scope = m_currentScope;
        scope != nullptr;
        scope = m_scopes[scope]->enclosingNode()
    )
    {
        if (auto decl = dynamic_cast<Declaration const*>(scope))
        {
            if (!ret.empty())
                ret = "." + ret;
            ret = decl->name() + ret;
        }
    }
    return ret;
}

}
}