path: root/libsolidity/analysis/ControlFlowGraph.cpp

/*
    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 <libsolidity/analysis/ControlFlowGraph.h>
#include <libsolidity/analysis/ControlFlowBuilder.h>

#include <boost/range/adaptor/reversed.hpp>

#include <algorithm>

using namespace std;
using namespace dev::solidity;

bool CFG::constructFlow(ASTNode const& _astRoot)
{
    _astRoot.accept(*this);
    applyModifiers();
    return Error::containsOnlyWarnings(m_errorReporter.errors());
}


bool CFG::visit(ModifierDefinition const& _modifier)
{
    m_modifierControlFlow[&_modifier] = ControlFlowBuilder::createModifierFlow(m_nodeContainer, _modifier);
    return false;
}

bool CFG::visit(FunctionDefinition const& _function)
{
    m_functionControlFlow[&_function] = ControlFlowBuilder::createFunctionFlow(m_nodeContainer, _function);
    return false;
}

FunctionFlow const& CFG::functionFlow(FunctionDefinition const& _function) const
{
    solAssert(m_functionControlFlow.count(&_function), "");
    return *m_functionControlFlow.find(&_function)->second;
}

CFGNode* CFG::NodeContainer::newNode()
{
    m_nodes.emplace_back(new CFGNode());
    return m_nodes.back().get();
}

void CFG::applyModifiers()
{
    for (auto const& function: m_functionControlFlow)
    {
        for (auto const& modifierInvocation: boost::adaptors::reverse(function.first->modifiers()))
        {
            if (auto modifierDefinition = dynamic_cast<ModifierDefinition const*>(
                modifierInvocation->name()->annotation().referencedDeclaration
            ))
            {
                solAssert(m_modifierControlFlow.count(modifierDefinition), "");
                applyModifierFlowToFunctionFlow(*m_modifierControlFlow[modifierDefinition], function.second.get());
            }
        }
    }
}

void CFG::applyModifierFlowToFunctionFlow(
    ModifierFlow const& _modifierFlow,
    FunctionFlow* _functionFlow
)
{
    solAssert(!!_functionFlow, "");

    map<CFGNode*, CFGNode*> copySrcToCopyDst;

    // inherit the revert node of the function
    copySrcToCopyDst[_modifierFlow.revert] = _functionFlow->revert;

    // replace the placeholder nodes by the function entry and exit
    copySrcToCopyDst[_modifierFlow.placeholderEntry] = _functionFlow->entry;
    copySrcToCopyDst[_modifierFlow.placeholderExit] = _functionFlow->exit;

    stack<CFGNode*> nodesToCopy;
    nodesToCopy.push(_modifierFlow.entry);

    // map the modifier entry to a new node that will become the new function entry
    copySrcToCopyDst[_modifierFlow.entry] = m_nodeContainer.newNode();

    while (!nodesToCopy.empty())
    {
        CFGNode* copySrcNode = nodesToCopy.top();
        nodesToCopy.pop();

        solAssert(copySrcToCopyDst.count(copySrcNode), "");

        CFGNode* copyDstNode = copySrcToCopyDst[copySrcNode];

        copyDstNode->block = copySrcNode->block;
        for (auto const& entry: copySrcNode->entries)
        {
            if (!copySrcToCopyDst.count(entry))
            {
                copySrcToCopyDst[entry] = m_nodeContainer.newNode();
                nodesToCopy.push(entry);
            }
            copyDstNode->entries.emplace_back(copySrcToCopyDst[entry]);
        }
        for (auto const& exit: copySrcNode->exits)
        {
            if (!copySrcToCopyDst.count(exit))
            {
                copySrcToCopyDst[exit] = m_nodeContainer.newNode();
                nodesToCopy.push(exit);
            }
            copyDstNode->exits.emplace_back(copySrcToCopyDst[exit]);
        }
    }

    // if the modifier control flow never reached its exit node,
    // we need to create a new (disconnected) exit node now
    if (!copySrcToCopyDst.count(_modifierFlow.exit))
        copySrcToCopyDst[_modifierFlow.exit] = m_nodeContainer.newNode();

    _functionFlow->entry = copySrcToCopyDst[_modifierFlow.entry];
    _functionFlow->exit = copySrcToCopyDst[_modifierFlow.exit];
}