C++ DSGraph::getScalarMap方法代码示例

/// OptimizeGlobals - This method uses information taken from DSA to optimize
/// global variables.
///
bool DSOpt::OptimizeGlobals(Module &M) {
  DSGraph* GG = TD->getGlobalsGraph();
  const DSGraph::ScalarMapTy &SM = GG->getScalarMap();
  bool Changed = false;

  for (Module::global_iterator I = M.global_begin(), E = M.global_end(); I != E; ++I)
    if (!I->isDeclaration()) { // Loop over all of the non-external globals...
      // Look up the node corresponding to this global, if it exists.
      DSNode *GNode = 0;
      DSGraph::ScalarMapTy::const_iterator SMI = SM.find(I);
      if (SMI != SM.end()) GNode = SMI->second.getNode();

      if (GNode == 0 && I->hasInternalLinkage()) {
        // If there is no entry in the scalar map for this global, it was never
        // referenced in the program.  If it has internal linkage, that means we
        // can delete it.  We don't ACTUALLY want to delete the global, just
        // remove anything that references the global: later passes will take
        // care of nuking it.
        if (!I->use_empty()) {
          I->replaceAllUsesWith(ConstantPointerNull::get(I->getType()));
          ++NumGlobalsIsolated;
        }
      } else if (GNode && GNode->NodeType.isCompleteNode()) {

        // If the node has not been read or written, and it is not externally
        // visible, kill any references to it so it can be DCE'd.
        if (!GNode->NodeType.isModifiedNode() && !GNode->NodeType.isReadNode() &&I->hasInternalLinkage()){
          if (!I->use_empty()) {
            I->replaceAllUsesWith(ConstantPointerNull::get(I->getType()));
            ++NumGlobalsIsolated;
          }
        }

        // We expect that there will almost always be a node for this global.
        // If there is, and the node doesn't have the M bit set, we can set the
        // 'constant' bit on the global.
        if (!GNode->NodeType.isModifiedNode() && !I->isConstant()) {
          I->setConstant(true);
          ++NumGlobalsConstanted;
          Changed = true;
        }
      }
    }
  return Changed;
}

//
// Method: TransformCollapsedAllocas()
//
// Description:
//  Transform all stack allocated objects that are type-unknown
//  (i.e., are completely folded) to heap allocations.
//
void
ConvertUnsafeAllocas::TransformCollapsedAllocas(Module &M) {
  //
  // Need to check if the following is incomplete because we are only looking
  // at scalars.
  //
  // It may be complete because every instruction actually is a scalar in
  // LLVM?!
  for (Module::iterator MI = M.begin(), ME = M.end(); MI != ME; ++MI) {
    if (!MI->isDeclaration()) {
      DSGraph *G = budsPass->getDSGraph(*MI);
      DSGraph::ScalarMapTy &SM = G->getScalarMap();
      for (DSGraph::ScalarMapTy::iterator SMI = SM.begin(), SME = SM.end();
           SMI != SME; ) {
        if (AllocaInst *AI = dyn_cast<AllocaInst>((Value *)(SMI->first))) {
          if (SMI->second.getNode()->isNodeCompletelyFolded()) {
            Value *AllocSize =
            ConstantInt::get(Int32Type,
                              TD->getTypeAllocSize(AI->getAllocatedType()));
            if (AI->isArrayAllocation())
              AllocSize = BinaryOperator::Create(Instruction::Mul, AllocSize,
                                                 AI->getOperand(0), "sizetmp",
                                                 AI);     

            CallInst *CI = CallInst::Create (kmalloc, AllocSize, "", AI);
            Value * MI = castTo (CI, AI->getType(), "", AI);
            InsertFreesAtEnd(CI);
            AI->replaceAllUsesWith(MI);
            SMI->second.getNode()->setHeapMarker();
            SM.erase(SMI++);
            AI->getParent()->getInstList().erase(AI);   
            ++ConvAllocas;
          } else {
            ++SMI;
          }
        } else {
          ++SMI;
        }
      }
    }
  }
}

//
// Method: getFunctionTargets()
//
// Description:
//  This method finds all of the potential targets of the specified indirect
//  function call.
//
void
CompleteChecks::getFunctionTargets (CallSite CS,
                                    std::vector<const Function *> & Targets) {
  EQTDDataStructures & dsaPass = getAnalysis<EQTDDataStructures>();
  const DSCallGraph & callgraph = dsaPass.getCallGraph();
  DSGraph* G = dsaPass.getGlobalsGraph();
  DSGraph::ScalarMapTy& SM = G->getScalarMap();

  DSCallGraph::callee_iterator csi = callgraph.callee_begin(CS);
  DSCallGraph::callee_iterator cse = callgraph.callee_end(CS);
  for (; csi != cse; ++csi) {
    const Function *F = *csi;
    DSCallGraph::scc_iterator sccii = callgraph.scc_begin(F),
      sccee = callgraph.scc_end(F);
    for (;sccii != sccee; ++sccii) {
      DSGraph::ScalarMapTy::const_iterator I = 
        SM.find(SM.getLeaderForGlobal(*sccii));
      if (I != SM.end() && !((*sccii)->isDeclaration())) {
        Targets.push_back (*sccii);
      }
    }
  }

  const Function *F1 = CS.getInstruction()->getParent()->getParent();
  F1 = callgraph.sccLeader(&*F1);
  DSCallGraph::scc_iterator sccii = callgraph.scc_begin(F1),
                 sccee = callgraph.scc_end(F1);
  for(;sccii != sccee; ++sccii) {
    DSGraph::ScalarMapTy::const_iterator I = 
      SM.find(SM.getLeaderForGlobal(*sccii));
    if (I != SM.end() && !((*sccii)->isDeclaration())) {
      Targets.push_back (*sccii);
    }
  }

  return;
}

//.........这里部分代码省略.........
  std::vector<const DSNode*> ArgNodes;
  DSGraph *CalleeGraph;  // The callee graph

  // For indirect callees, find any callee since all DS graphs have been
  // merged.
  if (CF) {   // Direct calls are nice and simple.
    DEBUG(errs() << "  Handling direct call: " << *TheCall << "\n");

    //
    // Do not try to add pool handles to the function if it:
    //  a) Already calls a cloned function; or
    //  b) Calls a function which was never cloned.
    //
    // For such a call, just replace any arguments that take original functions
    // with their cloned function poiner values.
    //
    FuncInfo *CFI = PAInfo.getFuncInfo(*CF);
    if (CFI == 0 || CFI->Clone == 0) {   // Nothing to transform...
      visitInstruction(*TheCall);
      return;
    }

    //
    // Oh, dear.  We must add pool descriptors to this direct call.
    //
    NewCallee = CFI->Clone;
    ArgNodes = CFI->ArgNodes;
    
    assert ((Graphs.hasDSGraph (*CF)) && "Function has no ECGraph!\n");
    CalleeGraph = Graphs.getDSGraph(*CF);
  } else {
    DEBUG(errs() << "  Handling indirect call: " << *TheCall << "\n");
    DSGraph *G =  Graphs.getGlobalsGraph();
    DSGraph::ScalarMapTy& SM = G->getScalarMap();

    // Here we fill in CF with one of the possible called functions.  Because we
    // merged together all of the arguments to all of the functions in the
    // equivalence set, it doesn't really matter which one we pick.
    // (If the function was cloned, we have to map the cloned call instruction
    // in CS back to the original call instruction.)
    Instruction *OrigInst =
      cast<Instruction>(getOldValueIfAvailable(CS.getInstruction()));

    //
    // Attempt to get one of the function targets of this indirect call site by
    // looking at the call graph constructed by the points-to analysis.  Be
    // sure to use the original call site from the original function; the
    // points-to analysis has no information on the clones we've created.
    //
    // Also, look for the target that has the greatest number of arguments that
    // have associated DSNodes.  This ensures that we pass the maximum number
    // of pools possible and prevents us from eliding a pool because we're
    // examining a target that doesn't need it.
    //
    const DSCallGraph & callGraph = Graphs.getCallGraph();

    DSCallGraph::callee_iterator I = callGraph.callee_begin(OrigInst);
    for (; I != callGraph.callee_end(OrigInst); ++I) {
      for(DSCallGraph::scc_iterator sccii = callGraph.scc_begin(*I),
                           sccee = callGraph.scc_end(*I); sccii != sccee; ++sccii){
        if(SM.find(SM.getLeaderForGlobal(*sccii)) == SM.end())
          continue;
        //
        // Get the information for this function.  Since this is coming from
        // DSA, it should be an original function.
        //

AliasAnalysis::AliasResult DSAAA::alias(const AliasAnalysis::Location& l1, const AliasAnalysis::Location& l2)
{
    DSAAA_TOTAL_ANSWER++;
	if (l1.Size == 0 || l2.Size == 0)
		return NoAlias;
    /// ? Zhiyuan: weired, l1 & l2's locations are both instructions, in my opinion, they should be operands
	const Value* v1 = (l1.Ptr)->stripPointerCasts();
	const Value* v2 = (l2.Ptr)->stripPointerCasts();


	if (!v1->getType()->isPointerTy() || !v2->getType()->isPointerTy())
		return NoAlias;

	if (v1 == v2) return MustAlias;

    DSGraph *G1 = getGraphForValue(v1);
    DSGraph *G2 = getGraphForValue(v2);
    assert((!G1 || !G2 || G1 == G2) && "Alias query for 2 different functions?");

    const Function *func = nullptr;
    /// Zhiyuan: Debug
    if (const Instruction *I = dyn_cast<Instruction>(v1)) {
        func = I->getParent()->getParent();
    }  else if (const Argument *A = dyn_cast<Argument>(v1)) {
        func = A->getParent();
    }  else if (const BasicBlock *BB = dyn_cast<BasicBlock>(v1)) {
        func = BB->getParent();
    }
    if (func != nullptr) {
        //errs() << "[DSAAA Debug] We are in function [" << func->getName() << "].\n";
        DEBUG_QueryFunctionSet.insert(func->getName().str());
    }
    DSAAA_TOTAL_QUERY_FUNCTIONS = DEBUG_QueryFunctionSet.size();
    // Get the graph to use...
    DSGraph* G = G1 ? G1 : (G2 ? G2 : TD->getGlobalsGraph());

    const DSGraph::ScalarMapTy &GSM = G->getScalarMap();
    DSGraph::ScalarMapTy::const_iterator I = GSM.find((Value*)v1);
    if (I == GSM.end()) return NoAlias;
    DSGraph::ScalarMapTy::const_iterator J = GSM.find((Value*)v2);
    if (J == GSM.end()) return NoAlias;

    DSNode  *N1 = I->second.getNode(),  *N2 = J->second.getNode();
    unsigned O1 = I->second.getOffset(), O2 = J->second.getOffset();
    if (N1 == nullptr || N2 == nullptr) {
        // Can't tell whether anything aliases null.
        errs() << "[DSAAA DEBUG] nullptr for this value. \n";
        return AliasAnalysis::alias(l1, l2);
    }

    if (!N1->isCompleteNode() && !N2->isCompleteNode()) {
//        if (llvm::DebugFlag) {
//            errs() << "We calculate MayAlias here.\n";
//            errs() << "v1 = " << *(l1.Ptr) << "; v2 = " << *(l2.Ptr) << "\n";
//            errs() << "N1 = " << N1 << "; N2 = " << N2 << "\n";
//            errs() << "N1 complete? " << N1->isCompleteNode() << "; N2 complete? " << N2->isCompleteNode() << "\n";
//        }
        if (N1 == N2) {
            DSAAA_INCOMPLETE_SAME_NODE++;
        }
        DSAAA_INCOMPLETE_NODE++;
        DEBUG_IncompleteNodeSet.insert(N1);
        DSAAA_INCOMPLETE_NODE_COUNT = DEBUG_IncompleteNodeSet.size();
        if ( llvm::DebugFlag && func != nullptr && func->getName().str() == "BZ2_decompress") {
            errs() << "[DSAAA DEBUG] # of referrers: " << N1->getNumReferrers() << "\n";
//            errs() << "[DSAAA DEBUG] # of links: " << N1->getLinkCount() << "\n";
            N1->print(errs(), G);
            const DSScalarMap &SM = G->getScalarMap();
            int refCount = 1;
            for (DSScalarMap::const_iterator i = SM.begin(); i != SM.end(); i++) {
                if (i->second.getNode() == N1 && refCount < 240) {
                    errs() << refCount++ <<": " << *(i->first) << "\n";
                }
            }
            //exit(0);
        }
        return AliasAnalysis::alias(l1, l2);
    }

    // We can only make a judgment if one of the nodes is complete.
    if (N1->isCompleteNode() || N2->isCompleteNode()) {
        if (N1 != N2) return NoAlias;   // Completely different nodes.

        // See if they point to different offsets...  if so, we may be able to
        // determine that they do not alias...
        if (O1 != O2) {
            uint64_t V1Size = l1.Size;
            uint64_t V2Size = l2.Size;
            if (O2 < O1) {    // Ensure that O1 <= O2
                std::swap(v1, v2);
                std::swap(O1, O2);
                std::swap(V1Size, V2Size);
            }

            if (O1+V1Size <= O2) return NoAlias;
        }
    }

  /**
   * Below added by Zhiyuan
//.........这里部分代码省略.........

void CallTargetFinder<dsa>::findIndTargets(Module &M)
{
  dsa* T = &getAnalysis<dsa>();
  const DSCallGraph & callgraph = T->getCallGraph();
  DSGraph* G = T->getGlobalsGraph();
  DSGraph::ScalarMapTy& SM = G->getScalarMap();
  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
    if (!I->isDeclaration())
      for (Function::iterator F = I->begin(), FE = I->end(); F != FE; ++F)
        for (BasicBlock::iterator B = F->begin(), BE = F->end(); B != BE; ++B)
          if (isa<CallInst>(B) || isa<InvokeInst>(B)) {
            CallSite cs(B);
            AllSites.push_back(cs);
            Function* CF = cs.getCalledFunction();

            if (isa<UndefValue>(cs.getCalledValue())) continue;
            if (isa<InlineAsm>(cs.getCalledValue())) continue;

            //
            // If the called function is casted from one function type to
            // another, peer into the cast instruction and pull out the actual
            // function being called.
            //
            if (!CF)
              CF = dyn_cast<Function>(cs.getCalledValue()->stripPointerCasts());

            if (!CF) {
              Value * calledValue = cs.getCalledValue()->stripPointerCasts();
              if (isa<ConstantPointerNull>(calledValue)) {
                ++DirCall;
                CompleteSites.insert(cs);
              } else {
                IndCall++;

                DSCallGraph::callee_iterator csi = callgraph.callee_begin(cs),
                                   cse = callgraph.callee_end(cs);
                while(csi != cse) {
                  const Function *F = *csi;
                  DSCallGraph::scc_iterator sccii = callgraph.scc_begin(F),
                    sccee = callgraph.scc_end(F);
                  for(;sccii != sccee; ++sccii) {
                    DSGraph::ScalarMapTy::const_iterator I = SM.find(SM.getLeaderForGlobal(*sccii));
                    if (I != SM.end()) {
                      IndMap[cs].push_back (*sccii);
                    }
                  }
                  ++csi;
                }
                const Function *F1 = (cs).getInstruction()->getParent()->getParent();
                F1 = callgraph.sccLeader(&*F1);
                
                DSCallGraph::scc_iterator sccii = callgraph.scc_begin(F1),
                  sccee = callgraph.scc_end(F1);
                for(;sccii != sccee; ++sccii) {
                  DSGraph::ScalarMapTy::const_iterator I = SM.find(SM.getLeaderForGlobal(*sccii));
                  if (I != SM.end()) {
                    IndMap[cs].push_back (*sccii);
                  }
                }

                DSNode* N = T->getDSGraph(*cs.getCaller())
                  ->getNodeForValue(cs.getCalledValue()).getNode();
                assert (N && "CallTarget: findIndTargets: No DSNode!");

                if (!N->isIncompleteNode() && !N->isExternalNode() && IndMap[cs].size()) {
                  CompleteSites.insert(cs);
                  ++CompleteInd;
                } 
                if (!N->isIncompleteNode() && !N->isExternalNode() && !IndMap[cs].size()) {
                  ++CompleteEmpty;
                  DEBUG(errs() << "Call site empty: '"
                                << cs.getInstruction()->getName()
                                << "' In '"
                                << cs.getInstruction()->getParent()->getParent()->getName()
                                << "'\n");
                }
              }
            } else {
              ++DirCall;
              IndMap[cs].push_back(CF);
              CompleteSites.insert(cs);
            }
          }

  //Print the indirect call Map:

for(std::map<CallSite, std::vector<const Function*> >::iterator indMapIt = IndMap.begin(); indMapIt != IndMap.end(); ++indMapIt )
{

   CallSite CS =  indMapIt->first;
   Instruction* Inst = CS.getInstruction();
   Inst->dump();

}


}

/// ProcessNodesReachableFromGlobals - If we inferred anything about nodes
/// reachable from globals, we have to make sure that we incorporate data for
/// all graphs that include those globals due to the nature of the globals
/// graph.
///
void StructureFieldVisitorBase::
ProcessNodesReachableFromGlobals(DSGraph &DSG,
                                 std::multimap<DSNode*,LatticeValue*> &NodeLVs){
  // Start by marking all nodes reachable from globals.
  DSScalarMap &SM = DSG.getScalarMap();
  if (SM.global_begin() == SM.global_end()) return;

  hash_set<const DSNode*> Reachable;
  for (DSScalarMap::global_iterator GI = SM.global_begin(),
         E = SM.global_end(); GI != E; ++GI)
    SM[*GI].getNode()->markReachableNodes(Reachable);
  if (Reachable.empty()) return;
  
  // If any of the nodes with dataflow facts are reachable from the globals
  // graph, we have to do the GG processing step.
  bool MustProcessThroughGlobalsGraph = false;
  for (std::multimap<DSNode*, LatticeValue*>::iterator I = NodeLVs.begin(),
         E = NodeLVs.end(); I != E; ++I)
    if (Reachable.count(I->first)) {
      MustProcessThroughGlobalsGraph = true;
      break;
    }
  
  if (!MustProcessThroughGlobalsGraph) return;
  Reachable.clear();

  // Compute the mapping from DSG to the globals graph.
  DSGraph::NodeMapTy DSGToGGMap;
  DSG.computeGToGGMapping(DSGToGGMap);

  // Most of the times when we find facts about things reachable from globals we
  // we are in the main graph.  This means that we have *all* of the globals
  // graph in this DSG.  To be efficient, we compute the minimum set of globals
  // that can reach any of the NodeLVs facts.
  //
  // I'm not aware of any wonderful way of computing the set of globals that
  // points to the set of nodes in NodeLVs that is not N^2 in either NodeLVs or
  // the number of globals, except to compute the inverse of DSG.  As such, we
  // compute the inverse graph of DSG, which basically has the edges going from
  // pointed to nodes to pointing nodes.  Because we only care about one
  // connectedness properties, we ignore field info.  In addition, we only
  // compute inverse of the portion of the graph reachable from the globals.
  std::set<std::pair<DSNode*,DSNode*> > InverseGraph;

  for (DSScalarMap::global_iterator GI = SM.global_begin(),
         E = SM.global_end(); GI != E; ++GI)
    ComputeInverseGraphFrom(SM[*GI].getNode(), InverseGraph);

  // Okay, now that we have our bastardized inverse graph, compute the set of
  // globals nodes reachable from our lattice nodes.
  for (std::multimap<DSNode*, LatticeValue*>::iterator I = NodeLVs.begin(),
         E = NodeLVs.end(); I != E; ++I)
    ComputeNodesReachableFrom(I->first, InverseGraph, Reachable);
 
  // Now that we know which nodes point to the data flow facts, figure out which
  // globals point to the data flow facts.
  std::set<GlobalValue*> Globals;
  for (hash_set<const DSNode*>::iterator I = Reachable.begin(),
         E = Reachable.end(); I != E; ++I)
    Globals.insert((*I)->globals_begin(), (*I)->globals_end());

  // Finally, loop over all of the DSGraphs for the program, computing
  // information for the graph if not done already, mapping the result into our
  // context.
  for (hash_map<const Function*, DSGraph*>::iterator GI = ECG.DSInfo.begin(),
         E = ECG.DSInfo.end(); GI != E; ++GI) {
    DSGraph &FG = *GI->second;
    // Graphs can contain multiple functions, only process the graph once.
    if (GI->first != FG.retnodes_begin()->first ||
        // Also, do not bother reprocessing DSG.
        &FG == &DSG)
      continue;

    bool GraphUsesGlobal = false;
    for (std::set<GlobalValue*>::iterator I = Globals.begin(),
           E = Globals.end(); I != E; ++I)
      if (FG.getScalarMap().count(*I)) {
        GraphUsesGlobal = true;
        break;
      }

    // If this graph does not contain the global at all, there is no reason to
    // even think about it.
    if (!GraphUsesGlobal) continue;

    // Otherwise, compute the full set of dataflow effects of the function.
    std::multimap<DSNode*, LatticeValue*> &FGF = getCalleeFacts(FG);
    //std::cerr << "Computed: " << FG.getFunctionNames() << "\n";

#if 0
    for (std::multimap<DSNode*, LatticeValue*>::iterator I = FGF.begin(),
           E = FGF.end(); I != E; ++I)
      I->second->dump();
#endif
    // Compute the mapping of nodes in the globals graph to the function's
//.........这里部分代码省略.........

// Precondition: Enforce that the alloca nodes haven't been already converted
void ConvertUnsafeAllocas::TransformAllocasToMallocs(std::list<DSNode *> 
                                                     & unsafeAllocaNodes) {

  std::list<DSNode *>::const_iterator iCurrent = unsafeAllocaNodes.begin(), 
                                      iEnd     = unsafeAllocaNodes.end();

  for (; iCurrent != iEnd; ++iCurrent) {
    DSNode *DSN = *iCurrent;
    
    // Now change the alloca instruction corresponding to the node  
    // to malloc 
    DSGraph *DSG = DSN->getParentGraph();
    DSGraph::ScalarMapTy &SM = DSG->getScalarMap();

#ifndef LLVA_KERNEL    
    Instruction *MI = 0;
#else
    Value *MI = 0;
#endif
    for (DSGraph::ScalarMapTy::iterator SMI = SM.begin(), SME = SM.end();
         SMI != SME; ) {
      bool stackAllocate = true;
      // If this is already a heap node, then you cannot allocate this on the
      // stack
      if (DSN->isHeapNode()) {
        stackAllocate = false;
      }

      if (SMI->second.getNode() == DSN) {
        if (AllocaInst *AI = dyn_cast<AllocaInst>((Value *)(SMI->first))) {
          //
          // Create a new heap allocation instruction.
          //
          if (AI->getParent() != 0) {
            //
            // Create an LLVM value representing the size of the allocation.
            // If it's an array allocation, we'll need to insert a
            // multiplication instruction to get the size times the number of
            // elements.
            //
            unsigned long size = TD->getTypeAllocSize(AI->getAllocatedType());
            Value *AllocSize = ConstantInt::get(Int32Type, size);
            if (AI->isArrayAllocation())
              AllocSize = BinaryOperator::Create(Instruction::Mul, AllocSize,
                                                 AI->getOperand(0), "sizetmp",
                                                 AI);     
            std::vector<Value *> args(1, AllocSize);
            CallInst *CI = CallInst::Create (kmalloc, args.begin(), args.end(), "", AI);
            MI = castTo (CI, AI->getType(), "", AI);
            DSN->setHeapMarker();
            AI->replaceAllUsesWith(MI);
            SM.erase(SMI++);
            AI->getParent()->getInstList().erase(AI);
            ++ConvAllocas;
            InsertFreesAtEnd(MI);
#ifndef LLVA_KERNEL     
            if (stackAllocate) {
              ArrayMallocs.insert(MI);
            }
#endif        
          } else {
            ++SMI;
          } 
        } else {
          ++SMI;
        }
      } else {
        ++SMI;
      }
    }
  }  
}