[SVF API] Delete ICFG Node/Edge / Create new abstract ICFG from ground?

[mirusu400]

Hello, I'm creating one analysis program using SVF and SVF-example .

What I want is to start with a function that I want in a huge program, and only draw the nodes that I use in that function on a CFG (as dot file).

The traverseOnICFG function has been implemented to search only nodes that originated from a particular function, but manipulating the ICFG seems to be impossible with the API provided. ICFG Class does not provide an API to add or remove.

Is there an API to create a new ICFG, or remove Node or Edge from an existing ICFG? Or, can I get some help for this?

---

Here are my example WIP code.

//===- svf-ex.cpp -- A driver example of SVF-------------------------------------//
//
//                     SVF: Static Value-Flow Analysis
//
// Copyright (C) <2013->  <Yulei Sui>
//

// This program 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.

// This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
//
//===-----------------------------------------------------------------------===//

/*
 // A driver program of SVF including usages of SVF APIs
 //
 // Author: Yulei Sui,
 */

#include "SVF-LLVM/LLVMUtil.h"
#include "Graphs/SVFG.h"
#include "WPA/Andersen.h"
#include "SVF-LLVM/SVFIRBuilder.h"
#include "Util/Options.h"

using namespace llvm;
using namespace std;
using namespace SVF;



Set<const ICFGNode*> visited;
/*!
 * An example to query/collect all successor nodes from a ICFGNode (iNode) along control-flow graph (ICFG)
 */
void traverseOnICFG(ICFG* icfg, const SVFInstruction* svfinst)
{
    // SVFInstruction* svfinst = LLVMModuleSet::getLLVMModuleSet()->getSVFInstruction(inst);

    ICFGNode* iNode = icfg->getICFGNode(svfinst);
    FIFOWorkList<const ICFGNode*> worklist;
    
    worklist.push(iNode);

    /// Traverse along VFG
    while (!worklist.empty())
    {
        const ICFGNode* iNode = worklist.pop();
        for (ICFGNode::const_iterator it = iNode->OutEdgeBegin(), eit =
                    iNode->OutEdgeEnd(); it != eit; ++it)
        {
            ICFGEdge* edge = *it;
            ICFGNode* succNode = edge->getDstNode();
            if (visited.find(succNode) == visited.end())
            {
                visited.insert(succNode);
                worklist.push(succNode);
            }
        }
    }
}

/*!
 * An example to query/collect all the uses of a definition of a value along value-flow graph (VFG)
 */
int main(int argc, char ** argv)
{
    llvm::LLVMContext context;
    llvm::SMDiagnostic error;
    Instruction* value = nullptr;

    std::vector<std::string> moduleNameVec;
    moduleNameVec = OptionBase::parseOptions(
            argc, argv, "Whole Program Points-to Analysis", "[options] <input-bitcode...>"
    );


    if (Options::WriteAnder() == "ir_annotator")
    {
        LLVMModuleSet::preProcessBCs(moduleNameVec);
    }

    SVFModule* svfModule = LLVMModuleSet::buildSVFModule(moduleNameVec);
    const SVFFunction* svfFunc = svfModule->getSVFFunction("main");
    const SVFBasicBlock *svfBlock = svfFunc->getEntryBlock();
    const SVFInstruction *svfInst = svfBlock->front();
    
    /// Build Program Assignment Graph (SVFIR)
    SVFIRBuilder builder(svfModule);
    SVFIR* pag = builder.build();

    /// Create Andersen's pointer analysis
    Andersen* ander = AndersenWaveDiff::createAndersenWaveDiff(pag);

    /// Query aliases
    /// aliasQuery(ander,value1,value2);

    /// Print points-to information
    /// printPts(ander, value1);

    /// Call Graph
    PTACallGraph* callgraph = ander->getPTACallGraph();

    /// ICFG
    ICFG* icfg = pag->getICFG();



    /// Value-Flow Graph (VFG)
    VFG* vfg = new VFG(callgraph);

    /// Sparse value-flow graph (SVFG)
    SVFGBuilder svfBuilder;
    SVFG* svfg = svfBuilder.buildFullSVFG(ander);
    // Instruction* value = nullptr;

    /// Collect uses of an LLVM Value
    // traverseOnVFG(svfg, value);

    /// Collect all successor nodes on ICFG
    // value = 
    traverseOnICFG(icfg, svfInst);

    // Remove nodes from the ICFG
    for (const std::pair<const unsigned int, SVF::ICFGNode*>& node : *icfg) {
         ICFGNode* icfgNode = node.second;
        std::cout << icfgNode << std::endl;
        if (visited.find(icfgNode) == visited.end()) {
            std::cout << "Removing node: " << icfgNode << std::endl;
            // Remove all edges
            // This got ERRORS!!!
            for (ICFGNode::const_iterator iter = icfgNode->OutEdgeBegin();
                iter != icfgNode->OutEdgeEnd(); ++iter)
            {
                SVF::ICFGEdge* edge = *iter;
                icfg->removeICFGEdge(edge);
            }

            icfg->removeICFGNode(icfgNode);
        }
    }

    // 3. Generate a dot file from the new ICFG
    icfg->dump("new_icfg.dot");

    // Print length of the path from the entry node to the exit node
    std::cout << "Length of the path from the entry node to the exit node: " << visited.size() << std::endl;

    // clean up memory
    // delete vfg;
    AndersenWaveDiff::releaseAndersenWaveDiff();
    SVFIR::releaseSVFIR();



    // svfModule->dumpModulesToFile(".svf.bc");
    LLVMModuleSet::getLLVMModuleSet()->dumpModulesToFile(".svf.bc");
    SVF::LLVMModuleSet::releaseLLVMModuleSet();

    llvm::llvm_shutdown();
    return 0;
}

[LeoneChen]

I have the same question. Do you have any progress?

[mirusu400]

@LeoneChen Maybe not.. But I wrote a simple python program that select nodes that I want to know, and remove it from dot file. Although not in the CFG abstract model, I was able to get the desired results from the dot file. You can check it here

[LeoneChen]

Thanks very much! It seems a good idea.