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/*
    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/>.
*/
/**
 * Analysis part of inline assembly.
 */

#pragma once

#include <liblangutil/Exceptions.h>
#include <liblangutil/EVMVersion.h>

#include <libyul/AsmScope.h>

#include <libyul/backends/evm/AbstractAssembly.h>

#include <libyul/AsmDataForward.h>

#include <boost/variant.hpp>
#include <boost/optional.hpp>

#include <functional>
#include <memory>

namespace langutil
{
class ErrorReporter;
struct SourceLocation;
}

namespace yul
{

struct AsmAnalysisInfo;

/**
 * Performs the full analysis stage, calls the ScopeFiller internally, then resolves
 * references and performs other checks.
 * If all these checks pass, code generation should not throw errors.
 */
class AsmAnalyzer: public boost::static_visitor<bool>
{
public:
    explicit AsmAnalyzer(
        AsmAnalysisInfo& _analysisInfo,
        langutil::ErrorReporter& _errorReporter,
        dev::solidity::EVMVersion _evmVersion,
        boost::optional<langutil::Error::Type> _errorTypeForLoose,
        AsmFlavour _flavour = AsmFlavour::Loose,
        ExternalIdentifierAccess::Resolver const& _resolver = ExternalIdentifierAccess::Resolver()
    ):
        m_resolver(_resolver),
        m_info(_analysisInfo),
        m_errorReporter(_errorReporter),
        m_evmVersion(_evmVersion),
        m_flavour(_flavour),
        m_errorTypeForLoose(_errorTypeForLoose)
    {}

    bool analyze(Block const& _block);

    bool operator()(Instruction const&);
    bool operator()(Literal const& _literal);
    bool operator()(Identifier const&);
    bool operator()(FunctionalInstruction const& _functionalInstruction);
    bool operator()(Label const& _label);
    bool operator()(ExpressionStatement const&);
    bool operator()(StackAssignment const&);
    bool operator()(Assignment const& _assignment);
    bool operator()(VariableDeclaration const& _variableDeclaration);
    bool operator()(FunctionDefinition const& _functionDefinition);
    bool operator()(FunctionCall const& _functionCall);
    bool operator()(If const& _if);
    bool operator()(Switch const& _switch);
    bool operator()(ForLoop const& _forLoop);
    bool operator()(Block const& _block);

private:
    /// Visits the statement and expects it to deposit one item onto the stack.
    bool expectExpression(Expression const& _expr);
    bool expectDeposit(int _deposit, int _oldHeight, langutil::SourceLocation const& _location);

    /// Verifies that a variable to be assigned to exists and has the same size
    /// as the value, @a _valueSize, unless that is equal to -1.
    bool checkAssignment(Identifier const& _assignment, size_t _valueSize = size_t(-1));

    Scope& scope(Block const* _block);
    void expectValidType(std::string const& type, langutil::SourceLocation const& _location);
    void warnOnInstructions(dev::solidity::Instruction _instr, langutil::SourceLocation const& _location);

    /// Depending on @a m_flavour and @a m_errorTypeForLoose, throws an internal compiler
    /// exception (if the flavour is not Loose), reports an error/warning
    /// (if m_errorTypeForLoose is set) or does nothing.
    void checkLooseFeature(langutil::SourceLocation const& _location, std::string const& _description);

    int m_stackHeight = 0;
    yul::ExternalIdentifierAccess::Resolver m_resolver;
    Scope* m_currentScope = nullptr;
    /// Variables that are active at the current point in assembly (as opposed to
    /// "part of the scope but not yet declared")
    std::set<Scope::Variable const*> m_activeVariables;
    AsmAnalysisInfo& m_info;
    langutil::ErrorReporter& m_errorReporter;
    dev::solidity::EVMVersion m_evmVersion;
    AsmFlavour m_flavour = AsmFlavour::Loose;
    boost::optional<langutil::Error::Type> m_errorTypeForLoose;
};

}