solidity/libyul/optimiser/NameSimplifier.cpp

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2020-08-06 19:44:50 +00:00
/*
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/NameSimplifier.h>
#include <libyul/optimiser/NameCollector.h>
#include <libyul/AsmData.h>
#include <libyul/Dialect.h>
#include <libyul/optimiser/OptimizerUtilities.h>
#include <libsolutil/CommonData.h>
#include <regex>
using namespace solidity::yul;
using namespace std;
NameSimplifier::NameSimplifier(
OptimiserStepContext& _context,
Block const& _ast
):
m_context(_context),
m_usedNames(_context.reservedIdentifiers)
{
for (YulString name: m_usedNames)
m_translations[name] = name;
set<YulString> allNames = NameCollector(_ast).names();
m_usedNames += allNames;
for (YulString name: allNames)
findSimplification(name);
}
void NameSimplifier::operator()(FunctionDefinition& _funDef)
{
translate(_funDef.name);
renameVariables(_funDef.parameters);
renameVariables(_funDef.returnVariables);
ASTModifier::operator()(_funDef);
}
void NameSimplifier::operator()(VariableDeclaration& _varDecl)
{
renameVariables(_varDecl.variables);
ASTModifier::operator()(_varDecl);
}
void NameSimplifier::renameVariables(vector<TypedName>& _variables)
{
for (TypedName& typedName: _variables)
translate(typedName.name);
}
void NameSimplifier::operator()(Identifier& _identifier)
{
translate(_identifier.name);
}
void NameSimplifier::operator()(FunctionCall& _funCall)
{
// The visitor on its own does not visit the function name.
if (!m_context.dialect.builtin(_funCall.functionName.name))
(*this)(_funCall.functionName);
ASTModifier::operator()(_funCall);
}
void NameSimplifier::findSimplification(YulString _name)
{
if (m_translations.count(_name))
return;
string name = _name.str();
static auto replacements = vector<pair<regex, string>>{
{regex("_\\$\\d+"), ""}, // removes AST IDs
{regex("(abi_..code.*)_to_.*"), "$1"}, // removes _to... for abi functions
{regex("(stringliteral_[0-9a-f][0-9a-f][0-9a-f][0-9a-f])[0-9a-f]*"), "$1"}, // shorten string literal
{regex("tuple_t_"), ""},
{regex("_memory_ptr"), ""},
{regex("_calldata_ptr"), "_calldata"},
{regex("_fromStack"), ""},
{regex("_storage_storage"), "_storage"},
{regex("_memory_memory"), "_memory"},
{regex("t_contract\\$_([^_]*)_"), "$1_"},
{regex("index_access_t_array"), "index_access"},
{regex("[0-9]*_$"), ""}
};
for (auto const& [pattern, substitute]: replacements)
{
string candidate = regex_replace(name, pattern, substitute);
if (
!isRestrictedIdentifier(m_context.dialect, YulString(candidate)) &&
!m_usedNames.count(YulString(candidate))
)
name = candidate;
}
if (name != _name.str())
{
m_usedNames.insert(YulString(name));
m_translations[_name] = YulString(name);
}
}
void NameSimplifier::translate(YulString& _name)
{
auto it = m_translations.find(_name);
if (it != m_translations.end())
_name = it->second;
}