solidity/libyul/optimiser/VarDeclPropagator.h

61 lines
1.9 KiB
C++

/*
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/>.
*/
#pragma once
#include <libyul/AsmDataForward.h>
#include <libyul/optimiser/ASTWalker.h>
#include <libyul/Exceptions.h>
#include <libyul/AsmDataForward.h>
#include <vector>
#include <set>
#include <map>
namespace yul
{
/**
* Rewrites Assignment statements into VariableDeclaration when the assignment's LHS
* variables had no value yet.
*
* It recursively walks through the AST and moves each declaration of variables to
* the first assignment within the same block (if possible)..
*/
class VarDeclPropagator: public ASTModifier
{
public:
using ASTModifier::operator();
void operator()(Block& _block) override;
void operator()(VariableDeclaration& _varDecl) override;
void operator()(Assignment& _assignment) override;
void operator()(Identifier& _ident) override;
private:
bool allVarNamesUninitialized(std::vector<Identifier> const& _variableNames) const;
bool isFullyLazyInitialized(std::vector<Identifier> const& _variableNames) const;
VariableDeclaration recreateVariableDeclaration(Assignment& _assignment);
private:
/// Holds a list of variables from current Block that have no value assigned yet.
std::map<YulString, TypedName> m_emptyVarDecls;
/// Holds a list variables (and their TypedName) within the current block.
std::map<YulString, TypedName> m_lazyInitializedVarDecls;
};
}