solidity/libyul/optimiser/VarDeclPropagator.cpp
2018-11-23 14:29:00 +01:00

127 lines
3.6 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/>.
*/
#include <libyul/optimiser/VarDeclPropagator.h>
#include <libyul/AsmData.h>
#include <libdevcore/CommonData.h>
#include <boost/range/algorithm_ext/erase.hpp>
#include <algorithm>
#include <map>
using namespace std;
using namespace dev;
using namespace yul;
void VarDeclPropagator::operator()(Block& _block)
{
map<YulString, TypedName> outerEmptyVarDecls;
map<YulString, TypedName> outerLazyInitializedVarDecls;
swap(m_emptyVarDecls, outerEmptyVarDecls);
swap(m_lazyInitializedVarDecls, outerLazyInitializedVarDecls);
ASTModifier::operator()(_block);
iterateReplacing(
_block.statements,
[this](Statement& _stmt) -> boost::optional<vector<Statement>>
{
if (_stmt.type() == typeid(VariableDeclaration))
{
VariableDeclaration& varDecl = boost::get<VariableDeclaration>(_stmt);
boost::remove_erase_if(
varDecl.variables,
[&](TypedName const& _typedName) { return m_lazyInitializedVarDecls.count(_typedName.name); }
);
if (varDecl.variables.empty())
return vector<Statement>{};
else
return {};
}
else if (_stmt.type() == typeid(Assignment))
{
Assignment& assignment = boost::get<Assignment>(_stmt);
if (isFullyLazyInitialized(assignment.variableNames))
return vector<Statement>{recreateVariableDeclaration(assignment)};
else
return {};
}
else
return {};
}
);
swap(m_emptyVarDecls, outerEmptyVarDecls);
swap(m_lazyInitializedVarDecls, outerLazyInitializedVarDecls);
}
void VarDeclPropagator::operator()(VariableDeclaration& _varDecl)
{
if (_varDecl.value)
visit(*_varDecl.value);
else
for (TypedName const& typedName: _varDecl.variables)
m_emptyVarDecls[typedName.name] = typedName;
}
void VarDeclPropagator::operator()(Assignment& _assignment)
{
visit(*_assignment.value);
if (allVarNamesUninitialized(_assignment.variableNames))
for (Identifier const& ident: _assignment.variableNames)
m_lazyInitializedVarDecls[ident.name] = m_emptyVarDecls[ident.name];
for (Identifier& name: _assignment.variableNames)
(*this)(name);
}
void VarDeclPropagator::operator()(Identifier& _ident)
{
m_emptyVarDecls.erase(_ident.name);
}
bool VarDeclPropagator::allVarNamesUninitialized(vector<Identifier> const& _variableNames) const
{
return all_of(
begin(_variableNames),
end(_variableNames),
[&](Identifier const& _ident) -> bool { return m_emptyVarDecls.count(_ident.name); }
);
}
bool VarDeclPropagator::isFullyLazyInitialized(vector<Identifier> const& _variableNames) const
{
return all_of(
begin(_variableNames),
end(_variableNames),
[&](Identifier const& ident) -> bool { return m_lazyInitializedVarDecls.count(ident.name); }
);
}
VariableDeclaration VarDeclPropagator::recreateVariableDeclaration(Assignment& _assignment)
{
TypedNameList variables;
for (Identifier const& varName: _assignment.variableNames)
{
variables.emplace_back(move(m_lazyInitializedVarDecls.at(varName.name)));
m_lazyInitializedVarDecls.erase(varName.name);
}
return VariableDeclaration{move(_assignment.location), move(variables), std::move(_assignment.value)};
}