Scoper: Walks Yul AST and assigns scopes

This is taken from DataFlowAnalyzer and will be used in the optimizer step MemoryLoadResolver.
This commit is contained in:
hrkrshnn 2020-12-28 22:49:14 +01:00
parent 8e9a5a02c2
commit c9ed116621
3 changed files with 146 additions and 0 deletions

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@ -160,6 +160,8 @@ add_library(yul
optimiser/RedundantAssignEliminator.h
optimiser/Rematerialiser.cpp
optimiser/Rematerialiser.h
optimiser/Scoper.h
optimiser/Scoper.cpp
optimiser/SSAReverser.cpp
optimiser/SSAReverser.h
optimiser/SSATransform.cpp

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@ -0,0 +1,88 @@
/*
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
#include <libyul/optimiser/Scoper.h>
#include <libyul/AST.h>
#include <libyul/Exceptions.h>
#include <libsolutil/CommonData.h>
#include <boost/range/adaptor/reversed.hpp>
#include <set>
using namespace solidity::yul;
using namespace solidity::util;
using namespace std;
void Scoper::operator()(VariableDeclaration& _varDecl)
{
set<YulString> names;
for (auto const& var: _varDecl.variables)
names.emplace(var.name);
m_variableScopes.back().variables += names;
ASTModifier::operator()(_varDecl);
}
void Scoper::operator()(FunctionDefinition& _fun)
{
pushScope(true);
for (auto const& parameter: _fun.parameters)
m_variableScopes.back().variables.emplace(parameter.name);
for (auto const& var: _fun.returnVariables)
{
m_variableScopes.back().variables.emplace(var.name);
}
ASTModifier::operator()(_fun);
popScope();
}
void Scoper::operator()(Block& _block)
{
size_t numScopes = m_variableScopes.size();
pushScope(false);
ASTModifier::operator()(_block);
popScope();
yulAssert(numScopes == m_variableScopes.size(), "");
}
void Scoper::pushScope(bool _functionScope)
{
m_variableScopes.emplace_back(_functionScope);
}
void Scoper::popScope()
{
m_variableScopes.pop_back();
}
bool Scoper::inScope(YulString _variableName) const
{
for (auto const& scope: m_variableScopes | boost::adaptors::reversed)
{
if (scope.variables.count(_variableName))
return true;
if (scope.isFunction)
return false;
}
return false;
}

56
libyul/optimiser/Scoper.h Normal file
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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
/**
* Base class that assigns scope to Yul AST
*/
#include <libyul/optimiser/ASTWalker.h>
#include <libyul/AST.h>
namespace solidity::yul
{
class Scoper: public ASTModifier
{
public:
using ASTModifier::operator();
void operator()(VariableDeclaration& _varDecl) override;
void operator()(FunctionDefinition& _fun) override;
void operator()(Block& _block) override;
protected:
/// Returns true iff the variable is in scope.
bool inScope(YulString _variableName) const;
/// Creates a new inner scope.
void pushScope(bool _functionScope);
/// Removes the innermost scope and clears all variables in it.
virtual void popScope();
struct Scope
{
explicit Scope(bool _isFunction): isFunction(_isFunction) {}
std::set<YulString> variables;
bool isFunction;
};
std::vector<Scope> m_variableScopes;
};
}