llvm/lib/Transforms/Instrumentation/ProfilePaths/RetracePath.cpp

//===----Instrumentation/ProfilePaths/RetracePath.cppTrigger.cpp--*- C++ -*--=//
//
// Retraces a path of BasicBlock, given a path number and a graph!
//
//===----------------------------------------------------------------------===//

#include "llvm/Module.h"
#include "llvm/iTerminators.h"
#include "llvm/iOther.h"
#include "llvm/Support/CFG.h"
#include "Graph.h"

using std::vector;
using std::map;
using std::cerr;

//Routines to get the path trace!

void getPathFrmNode(Node *n, vector<BasicBlock*> &vBB, int pathNo, Graph g, 
		    vector<Edge> &stDummy, vector<Edge> &exDummy, 
		    vector<Edge> &be,
		    double strand){
  Graph::nodeList nlist=g.getNodeList(n);
  
  int maxCount=-9999999;
  bool isStart=false;

  if(*n==*g.getRoot())//its root: so first node of path
    isStart=true;

  double edgeRnd=0;
  Node *nextRoot=n;
  for(Graph::nodeList::iterator NLI=nlist.begin(), NLE=nlist.end(); NLI!=NLE;
      ++NLI){
    if(NLI->weight>maxCount && NLI->weight<=pathNo){
      maxCount=NLI->weight;
      nextRoot=NLI->element;
      edgeRnd=NLI->randId;
      if(isStart)
	strand=NLI->randId;
    }
  }

  if(!isStart)
    assert(strand!=-1 && "strand not assigned!"); 

  assert(!(*nextRoot==*n && pathNo>0) && "No more BBs to go");
  assert(!(*nextRoot==*g.getExit() && pathNo-maxCount!=0) && "Reached exit");

  vBB.push_back(n->getElement());

  if(pathNo-maxCount==0 && *nextRoot==*g.getExit()){

    //look for strnd and edgeRnd now:
    bool has1=false, has2=false;
    //check if exit has it
    for(vector<Edge>::iterator VI=exDummy.begin(), VE=exDummy.end(); VI!=VE; 
	++VI){
      if(VI->getRandId()==edgeRnd){
	has2=true;
	break;
      }
    }

    //check if start has it
    for(vector<Edge>::iterator VI=stDummy.begin(), VE=stDummy.end(); VI!=VE; 
	++VI){
      if(VI->getRandId()==strand){
	has1=true;
	break;
      }
    }

    if(has1){
      //find backedge with endpoint vBB[1]
      for(vector<Edge>::iterator VI=be.begin(), VE=be.end(); VI!=VE; ++VI){
	assert(vBB.size()>0 && "vector too small");
	if( VI->getSecond()->getElement() == vBB[1] ){
	  //vBB[0]=VI->getFirst()->getElement();
          vBB.erase(vBB.begin());
	  break;
	}
      }
    }

    if(has2){
      //find backedge with startpoint vBB[vBB.size()-1]
      for(vector<Edge>::iterator VI=be.begin(), VE=be.end(); VI!=VE; ++VI){
	assert(vBB.size()>0 && "vector too small");
	if( VI->getFirst()->getElement() == vBB[vBB.size()-1] && 
            VI->getSecond()->getElement() == vBB[0]){
	  //vBB.push_back(VI->getSecond()->getElement());
	  break;
	}
      }
    }
    else 
      vBB.push_back(nextRoot->getElement());
   
    return;
  }

  assert(pathNo-maxCount>=0);

  return getPathFrmNode(nextRoot, vBB, pathNo-maxCount, g, stDummy, 
			exDummy, be, strand);
}


static Node *findBB(std::vector<Node *> &st, BasicBlock *BB){
  for(std::vector<Node *>::iterator si=st.begin(); si!=st.end(); ++si){
    if(((*si)->getElement())==BB){
      return *si;
    }
  }
  return NULL;
}

void getBBtrace(vector<BasicBlock *> &vBB, int pathNo, Function *M){
  //step 1: create graph
  //Transform the cfg s.t. we have just one exit node
  
  std::vector<Node *> nodes;
  std::vector<Edge> edges;
  Node *tmp;
  Node *exitNode=0, *startNode=0;
  static std::map<Function *, Graph *> graphMap;
  static std::map<Function *, vector<Edge> > stMap, exMap, beMap; 

  if(!graphMap[M]){
    BasicBlock *ExitNode = 0;
    for (Function::iterator I = M->begin(), E = M->end(); I != E; ++I){
      if (isa<ReturnInst>(I->getTerminator())) {
        ExitNode = &*I;
        break;
      }
    }
  
    assert(ExitNode!=0 && "exitnode not found");

    //iterating over BBs and making graph 
    //The nodes must be uniquely identified:
    //That is, no two nodes must hav same BB*
  
    //First enter just nodes: later enter edges
    for(Function::iterator BB = M->begin(), BE=M->end(); BB != BE; ++BB){
      if(BB->size()==2){
        const Instruction *inst = BB->getInstList().begin();
        if(isa<CallInst>(inst)){
          Instruction *ii1 = BB->getInstList().begin();
          CallInst *callInst = dyn_cast<CallInst>(ii1);
          if(callInst->getCalledFunction()->getName()=="trigger")
            continue;
        }
      }
      Node *nd=new Node(BB);
      nodes.push_back(nd); 
      if(&*BB==ExitNode)
        exitNode=nd;
      if(&*BB==&M->front())
        startNode=nd;
    }

    assert(exitNode!=0 && startNode!=0 && "Start or exit not found!");
 
    for (Function::iterator BB = M->begin(), BE=M->end(); BB != BE; ++BB){
      if(BB->size()==2){
        const Instruction *inst = BB->getInstList().begin();
        if(isa<CallInst>(inst)){
          Instruction *ii1 = BB->getInstList().begin();
          CallInst *callInst = dyn_cast<CallInst>(ii1);
          if(callInst->getCalledFunction()->getName()=="trigger")
            continue;
        }
      }

      Node *nd=findBB(nodes, BB);
      assert(nd && "No node for this edge!");

      for(BasicBlock::succ_iterator s=succ_begin(&*BB), se=succ_end(&*BB); 
          s!=se; ++s){
        if((*s)->size()==2){
          const Instruction *inst = (*s)->getInstList().begin();
          if(isa<CallInst>(inst)){
            Instruction *ii1 = (*s)->getInstList().begin();
            CallInst *callInst = dyn_cast<CallInst>(ii1);
            if(callInst->getCalledFunction()->getName()=="trigger")
              continue;
          }
        }

        Node *nd2=findBB(nodes,*s);
        assert(nd2 && "No node for this edge!");
        Edge ed(nd,nd2,0);
        edges.push_back(ed);
      }
    }
  
    graphMap[M]= new Graph(nodes,edges, startNode, exitNode);
 
    Graph *g = graphMap[M];

    if (M->size() <= 1) return; //uninstrumented 

    //step 2: getBackEdges
    //vector<Edge> be;
    std::map<Node *, int> nodePriority;
    g->getBackEdges(beMap[M], nodePriority);

    //step 3: add dummy edges
    //vector<Edge> stDummy;
    //vector<Edge> exDummy;
    addDummyEdges(stMap[M], exMap[M], *g, beMap[M]);

    //step 4: value assgn to edges
    int numPaths = valueAssignmentToEdges(*g, nodePriority, beMap[M]);
  }

  //step 5: now travel from root, select max(edge) < pathNo, 
  //and go on until reach the exit
  return getPathFrmNode(graphMap[M]->getRoot(), vBB, pathNo, *graphMap[M], 
                        stMap[M], exMap[M], beMap[M], -1);
}