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path: root/libsolidity/analysis/ReferencesResolver.cpp
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/*
    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 resolves type names to types and annotates the AST accordingly.
 */

#include <libsolidity/analysis/ReferencesResolver.h>
#include <libsolidity/ast/AST.h>
#include <libsolidity/analysis/NameAndTypeResolver.h>
#include <libsolidity/interface/Exceptions.h>
#include <libsolidity/analysis/ConstantEvaluator.h>

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


bool ReferencesResolver::visit(Return const& _return)
{
    _return.annotation().functionReturnParameters = m_returnParameters;
    return true;
}

void ReferencesResolver::endVisit(NewExpression const& _new)
{
    typeFor(_new.typeName());
}

bool ReferencesResolver::visit(UserDefinedTypeName const& _typeName)
{
    Declaration const* declaration = m_resolver.pathFromCurrentScope(_typeName.namePath());
    if (!declaration)
        fatalDeclarationError(_typeName.location(), "Identifier not found or not unique.");

    _typeName.annotation().referencedDeclaration = declaration;

    return true;
}

bool ReferencesResolver::resolve(ASTNode const& _root)
{
    try
    {
        _root.accept(*this);
    }
    catch (FatalError const&)
    {
        solAssert(m_errorOccurred, "");
    }
    return !m_errorOccurred;
}

bool ReferencesResolver::visit(Identifier const& _identifier)
{
    auto declarations = m_resolver.nameFromCurrentScope(_identifier.name());
    if (declarations.empty())
        fatalDeclarationError(_identifier.location(), "Undeclared identifier.");
    else if (declarations.size() == 1)
        _identifier.annotation().referencedDeclaration = declarations.front();
    else
        _identifier.annotation().overloadedDeclarations =
            m_resolver.cleanedDeclarations(_identifier, declarations);
    return false;
}

void ReferencesResolver::endVisit(VariableDeclaration const& _variable)
{
    if (_variable.annotation().type)
        return;

    TypePointer type;
    if (_variable.typeName())
    {
        type = typeFor(*_variable.typeName());
        using Location = VariableDeclaration::Location;
        Location loc = _variable.referenceLocation();
        // References are forced to calldata for external function parameters (not return)
        // and memory for parameters (also return) of publicly visible functions.
        // They default to memory for function parameters and storage for local variables.
        // As an exception, "storage" is allowed for library functions.
        if (auto ref = dynamic_cast<ReferenceType const*>(type.get()))
        {
            if (_variable.isExternalCallableParameter())
            {
                auto const& contract = dynamic_cast<ContractDefinition const&>(*_variable.scope()->scope());
                if (contract.isLibrary())
                {
                    if (loc == Location::Memory)
                        fatalTypeError(_variable.location(),
                            "Location has to be calldata or storage for external "
                            "library functions (remove the \"memory\" keyword)."
                        );
                }
                else
                {
                    // force location of external function parameters (not return) to calldata
                    if (loc != Location::Default)
                        fatalTypeError(_variable.location(),
                            "Location has to be calldata for external functions "
                            "(remove the \"memory\" or \"storage\" keyword)."
                        );
                }
                if (loc == Location::Default)
                    type = ref->copyForLocation(DataLocation::CallData, true);
            }
            else if (_variable.isCallableParameter() && _variable.scope()->isPublic())
            {
                auto const& contract = dynamic_cast<ContractDefinition const&>(*_variable.scope()->scope());
                // force locations of public or external function (return) parameters to memory
                if (loc == Location::Storage && !contract.isLibrary())
                    fatalTypeError(_variable.location(),
                        "Location has to be memory for publicly visible functions "
                        "(remove the \"storage\" keyword)."
                    );
                if (loc == Location::Default || !contract.isLibrary())
                    type = ref->copyForLocation(DataLocation::Memory, true);
            }
            else
            {
                if (_variable.isConstant())
                {
                    if (loc != Location::Default && loc != Location::Memory)
                        fatalTypeError(
                            _variable.location(),
                            "Storage location has to be \"memory\" (or unspecified) for constants."
                        );
                    loc = Location::Memory;
                }
                if (loc == Location::Default)
                    loc = _variable.isCallableParameter() ? Location::Memory : Location::Storage;
                bool isPointer = !_variable.isStateVariable();
                type = ref->copyForLocation(
                    loc == Location::Memory ?
                    DataLocation::Memory :
                    DataLocation::Storage,
                    isPointer
                );
            }
        }
        else if (loc != Location::Default && !ref)
            fatalTypeError(_variable.location(), "Storage location can only be given for array or struct types.");

        if (!type)
            fatalTypeError(_variable.location(), "Invalid type name.");

    }
    else if (!_variable.canHaveAutoType())
        fatalTypeError(_variable.location(), "Explicit type needed.");
    // otherwise we have a "var"-declaration whose type is resolved by the first assignment

    _variable.annotation().type = type;
}

TypePointer ReferencesResolver::typeFor(TypeName const& _typeName)
{
    if (_typeName.annotation().type)
        return _typeName.annotation().type;

    TypePointer type;
    if (auto elemTypeName = dynamic_cast<ElementaryTypeName const*>(&_typeName))
        type = Type::fromElementaryTypeName(elemTypeName->typeName());
    else if (auto typeName = dynamic_cast<UserDefinedTypeName const*>(&_typeName))
    {
        Declaration const* declaration = typeName->annotation().referencedDeclaration;
        solAssert(!!declaration, "");

        if (StructDefinition const* structDef = dynamic_cast<StructDefinition const*>(declaration))
            type = make_shared<StructType>(*structDef);
        else if (EnumDefinition const* enumDef = dynamic_cast<EnumDefinition const*>(declaration))
            type = make_shared<EnumType>(*enumDef);
        else if (ContractDefinition const* contract = dynamic_cast<ContractDefinition const*>(declaration))
            type = make_shared<ContractType>(*contract);
        else
            fatalTypeError(typeName->location(), "Name has to refer to a struct, enum or contract.");
    }
    else if (auto mapping = dynamic_cast<Mapping const*>(&_typeName))
    {
        TypePointer keyType = typeFor(mapping->keyType());
        TypePointer valueType = typeFor(mapping->valueType());
        // Convert key type to memory.
        keyType = ReferenceType::copyForLocationIfReference(DataLocation::Memory, keyType);
        // Convert value type to storage reference.
        valueType = ReferenceType::copyForLocationIfReference(DataLocation::Storage, valueType);
        type = make_shared<MappingType>(keyType, valueType);
    }
    else if (auto arrayType = dynamic_cast<ArrayTypeName const*>(&_typeName))
    {
        TypePointer baseType = typeFor(arrayType->baseType());
        if (baseType->storageBytes() == 0)
            fatalTypeError(arrayType->baseType().location(), "Illegal base type of storage size zero for array.");
        if (Expression const* length = arrayType->length())
        {
            if (!length->annotation().type)
                ConstantEvaluator e(*length);

            auto const* lengthType = dynamic_cast<IntegerConstantType const*>(length->annotation().type.get());
            if (!lengthType)
                fatalTypeError(length->location(), "Invalid array length.");
            else
                type = make_shared<ArrayType>(DataLocation::Storage, baseType, lengthType->literalValue(nullptr));
        }
        else
            type = make_shared<ArrayType>(DataLocation::Storage, baseType);
    }

    return _typeName.annotation().type = move(type);
}

void ReferencesResolver::typeError(SourceLocation const& _location, string const& _description)
{
    auto err = make_shared<Error>(Error::Type::TypeError);
    *err << errinfo_sourceLocation(_location) << errinfo_comment(_description);
    m_errorOccurred = true;
    m_errors.push_back(err);
}

void ReferencesResolver::fatalTypeError(SourceLocation const& _location, string const& _description)
{
    typeError(_location, _description);
    BOOST_THROW_EXCEPTION(FatalError());
}

void ReferencesResolver::declarationError(SourceLocation const& _location, string const& _description)
{
    auto err = make_shared<Error>(Error::Type::DeclarationError);
    *err << errinfo_sourceLocation(_location) << errinfo_comment(_description);
    m_errorOccurred = true;
    m_errors.push_back(err);
}

void ReferencesResolver::fatalDeclarationError(SourceLocation const& _location, string const& _description)
{
    declarationError(_location, _description);
    BOOST_THROW_EXCEPTION(FatalError());
}