solidity/libyul/optimiser/VarNameCleaner.cpp

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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/>.
*/
#include <libyul/optimiser/VarNameCleaner.h>
#include <libyul/AsmData.h>
#include <libyul/Dialect.h>
#include <algorithm>
#include <cctype>
#include <climits>
#include <iterator>
#include <string>
#include <regex>
using namespace yul;
using namespace std;
VarNameCleaner::VarNameCleaner(
Block const& _ast,
Dialect const& _dialect,
set<YulString> _blacklist
):
m_dialect{_dialect},
m_blacklist{std::move(_blacklist)},
m_translatedNames{}
{
for (auto const& statement: _ast.statements)
if (statement.type() == typeid(FunctionDefinition))
m_blacklist.insert(boost::get<FunctionDefinition>(statement).name);
m_usedNames = m_blacklist;
}
void VarNameCleaner::operator()(FunctionDefinition& _funDef)
{
yulAssert(!m_insideFunction, "");
m_insideFunction = true;
set<YulString> globalUsedNames = std::move(m_usedNames);
m_usedNames = m_blacklist;
map<YulString, YulString> globalTranslatedNames;
swap(globalTranslatedNames, m_translatedNames);
renameVariables(_funDef.parameters);
renameVariables(_funDef.returnVariables);
ASTModifier::operator()(_funDef);
swap(globalUsedNames, m_usedNames);
swap(globalTranslatedNames, m_translatedNames);
m_insideFunction = false;
}
void VarNameCleaner::operator()(VariableDeclaration& _varDecl)
{
renameVariables(_varDecl.variables);
ASTModifier::operator()(_varDecl);
}
void VarNameCleaner::renameVariables(vector<TypedName>& _variables)
{
for (TypedName& typedName: _variables)
{
auto newName = findCleanName(typedName.name);
if (newName != typedName.name)
{
m_translatedNames[typedName.name] = newName;
typedName.name = newName;
}
m_usedNames.insert(typedName.name);
}
}
void VarNameCleaner::operator()(Identifier& _identifier)
{
auto name = m_translatedNames.find(_identifier.name);
if (name != m_translatedNames.end())
_identifier.name = name->second;
}
YulString VarNameCleaner::findCleanName(YulString const& _name) const
{
auto newName = stripSuffix(_name);
if (newName != YulString{} && !isUsedName(newName))
return newName;
// create new name with suffix (by finding a free identifier)
for (size_t i = 1; i < numeric_limits<decltype(i)>::max(); ++i)
{
YulString newNameSuffixed = YulString{newName.str() + "_" + to_string(i)};
if (!isUsedName(newNameSuffixed))
return newNameSuffixed;
}
yulAssert(false, "Exhausted by attempting to find an available suffix.");
}
bool VarNameCleaner::isUsedName(YulString const& _name) const
{
return m_dialect.builtin(_name) || m_usedNames.count(_name);
}
YulString VarNameCleaner::stripSuffix(YulString const& _name) const
{
static regex const suffixRegex("(_+[0-9]+)+$");
smatch suffixMatch;
if (regex_search(_name.str(), suffixMatch, suffixRegex))
return {YulString{suffixMatch.prefix().str()}};
return _name;
}