solidity/libyul/backends/evm/VariableReferenceCounter.h

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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/>.
*/
// SPDX-License-Identifier: GPL-3.0
/**
* Counts the number of references to a variable.
*/
#pragma once
#include <libyul/optimiser/ASTWalker.h>
#include <libyul/Scope.h>
namespace solidity::yul
{
struct AsmAnalysisInfo;
/**
* Counts the number of references to a variable. This includes actual (read) references
* but also assignments to the variable. It does not include the declaration itself or
* function parameters, but it does include function return parameters.
*
* This component can handle multiple variables of the same name.
*
* Can only be applied to strict assembly.
*/
struct VariableReferenceCounter: public yul::ASTWalker
{
public:
static std::map<Scope::Variable const*, unsigned> run(AsmAnalysisInfo const& _assemblyInfo, Block const& _block)
{
VariableReferenceCounter variableReferenceCounter(_assemblyInfo);
variableReferenceCounter(_block);
return std::move(variableReferenceCounter.m_variableReferences);
}
protected:
void operator()(Block const& _block) override;
void operator()(Identifier const& _identifier) override;
void operator()(FunctionDefinition const&) override;
void operator()(ForLoop const&) override;
private:
explicit VariableReferenceCounter(
AsmAnalysisInfo const& _assemblyInfo
): m_info(_assemblyInfo)
{}
void increaseRefIfFound(YulString _variableName);
AsmAnalysisInfo const& m_info;
Scope* m_scope = nullptr;
std::map<Scope::Variable const*, unsigned> m_variableReferences;
};
}