solidity/libyul/optimiser/CallGraphGenerator.cpp

109 lines
2.9 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/>.
*/
// SPDX-License-Identifier: GPL-3.0
/**
* Specific AST walker that generates the call graph.
*/
#include <libyul/AsmData.h>
#include <libyul/optimiser/CallGraphGenerator.h>
#include <libevmasm/Instruction.h>
#include <stack>
using namespace std;
using namespace solidity;
using namespace solidity::yul;
using namespace solidity::util;
namespace
{
// TODO: This algorithm is non-optimal.
struct CallGraphCycleFinder
{
CallGraph const& callGraph;
set<YulString> containedInCycle{};
set<YulString> visited{};
vector<YulString> currentPath{};
void visit(YulString _function)
{
if (visited.count(_function))
return;
if (
auto it = find(currentPath.begin(), currentPath.end(), _function);
it != currentPath.end()
)
containedInCycle.insert(it, currentPath.end());
else
{
currentPath.emplace_back(_function);
if (callGraph.functionCalls.count(_function))
for (auto const& child: callGraph.functionCalls.at(_function))
visit(child);
currentPath.pop_back();
visited.insert(_function);
}
}
};
}
set<YulString> CallGraph::recursiveFunctions() const
{
CallGraphCycleFinder cycleFinder{*this};
// Visiting the root only is not enough, since there may be disconnected recursive functions.
for (auto const& call: functionCalls)
cycleFinder.visit(call.first);
return cycleFinder.containedInCycle;
}
CallGraph CallGraphGenerator::callGraph(Block const& _ast)
{
CallGraphGenerator gen;
gen(_ast);
return std::move(gen.m_callGraph);
}
void CallGraphGenerator::operator()(FunctionCall const& _functionCall)
{
m_callGraph.functionCalls[m_currentFunction].insert(_functionCall.functionName.name);
ASTWalker::operator()(_functionCall);
}
void CallGraphGenerator::operator()(ForLoop const& _forLoop)
{
m_callGraph.functionsWithLoops.insert(m_currentFunction);
ASTWalker::operator()(_forLoop);
}
void CallGraphGenerator::operator()(FunctionDefinition const& _functionDefinition)
{
YulString previousFunction = m_currentFunction;
m_currentFunction = _functionDefinition.name;
yulAssert(m_callGraph.functionCalls.count(m_currentFunction) == 0, "");
m_callGraph.functionCalls[m_currentFunction] = {};
ASTWalker::operator()(_functionDefinition);
m_currentFunction = previousFunction;
}
CallGraphGenerator::CallGraphGenerator()
{
m_callGraph.functionCalls[YulString{}] = {};
}