path: root/libyul/backends/evm/EVMCodeTransform.h

/*
    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/>.
*/
/**
 * Common code generator for translating Yul / inline assembly to EVM and EVM1.5.
 */

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

#include <libyul/ASTDataForward.h>

#include <libsolidity/inlineasm/AsmScope.h>

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

namespace dev
{
namespace solidity
{
class ErrorReporter;
namespace assembly
{
struct AsmAnalysisInfo;
}
}
namespace yul
{
class EVMAssembly;

class CodeTransform: public boost::static_visitor<>
{
public:
    /// Create the code transformer.
    /// @param _identifierAccess used to resolve identifiers external to the inline assembly
    CodeTransform(
        yul::AbstractAssembly& _assembly,
        solidity::assembly::AsmAnalysisInfo& _analysisInfo,
        bool _yul = false,
        bool _evm15 = false,
        ExternalIdentifierAccess const& _identifierAccess = ExternalIdentifierAccess(),
        bool _useNamedLabelsForFunctions = false
    ): CodeTransform(
        _assembly,
        _analysisInfo,
        _yul,
        _evm15,
        _identifierAccess,
        _useNamedLabelsForFunctions,
        _assembly.stackHeight(),
        std::make_shared<Context>()
    )
    {
    }

protected:
    struct Context
    {
        using Scope = solidity::assembly::Scope;
        std::map<Scope::Label const*, AbstractAssembly::LabelID> labelIDs;
        std::map<Scope::Function const*, AbstractAssembly::LabelID> functionEntryIDs;
        std::map<Scope::Variable const*, int> variableStackHeights;
    };

    CodeTransform(
        yul::AbstractAssembly& _assembly,
        solidity::assembly::AsmAnalysisInfo& _analysisInfo,
        bool _yul,
        bool _evm15,
        ExternalIdentifierAccess const& _identifierAccess,
        bool _useNamedLabelsForFunctions,
        int _stackAdjustment,
        std::shared_ptr<Context> _context
    ):
        m_assembly(_assembly),
        m_info(_analysisInfo),
        m_yul(_yul),
        m_evm15(_evm15),
        m_useNamedLabelsForFunctions(_useNamedLabelsForFunctions),
        m_identifierAccess(_identifierAccess),
        m_stackAdjustment(_stackAdjustment),
        m_context(_context)
    {}

public:
    void operator()(Instruction const& _instruction);
    void operator()(Literal const& _literal);
    void operator()(Identifier const& _identifier);
    void operator()(FunctionalInstruction const& _instr);
    void operator()(FunctionCall const&);
    void operator()(ExpressionStatement const& _statement);
    void operator()(Label const& _label);
    void operator()(StackAssignment const& _assignment);
    void operator()(Assignment const& _assignment);
    void operator()(VariableDeclaration const& _varDecl);
    void operator()(If const& _if);
    void operator()(Switch const& _switch);
    void operator()(FunctionDefinition const&);
    void operator()(ForLoop const&);
    void operator()(Block const& _block);

private:
    AbstractAssembly::LabelID labelFromIdentifier(Identifier const& _identifier);
    /// @returns the label ID corresponding to the given label, allocating a new one if
    /// necessary.
    AbstractAssembly::LabelID labelID(solidity::assembly::Scope::Label const& _label);
    AbstractAssembly::LabelID functionEntryID(YulString _name, solidity::assembly::Scope::Function const& _function);
    /// Generates code for an expression that is supposed to return a single value.
    void visitExpression(Expression const& _expression);

    void visitStatements(std::vector<Statement> const& _statements);

    /// Pops all variables declared in the block and checks that the stack height is equal
    /// to @a _blackStartStackHeight.
    void finalizeBlock(Block const& _block, int _blockStartStackHeight);

    void generateMultiAssignment(std::vector<Identifier> const& _variableNames);
    void generateAssignment(Identifier const& _variableName);

    /// Determines the stack height difference to the given variables. Throws
    /// if it is not yet in scope or the height difference is too large. Returns
    /// the (positive) stack height difference otherwise.
    int variableHeightDiff(solidity::assembly::Scope::Variable const& _var, bool _forSwap) const;

    void expectDeposit(int _deposit, int _oldHeight) const;

    void checkStackHeight(void const* _astElement) const;

    yul::AbstractAssembly& m_assembly;
    solidity::assembly::AsmAnalysisInfo& m_info;
    solidity::assembly::Scope* m_scope = nullptr;
    bool m_yul = false;
    bool m_evm15 = false;
    bool m_useNamedLabelsForFunctions = false;
    ExternalIdentifierAccess m_identifierAccess;
    /// Adjustment between the stack height as determined during the analysis phase
    /// and the stack height in the assembly. This is caused by an initial stack being present
    /// for inline assembly and different stack heights depending on the EVM backend used
    /// (EVM 1.0 or 1.5).
    int m_stackAdjustment = 0;
    std::shared_ptr<Context> m_context;
};

}
}