C++ DSNode::isUnknownNode方法代码示例

//
// Function: makeFSParameterCallsComplete()
//
// Description:
//  Finds calls to sc.fsparameter and fills in the completeness byte which
//  is the last argument to such call. The second argument to the function
//  is the one which is analyzed for completeness.
//
// Inputs:
//  M      - Reference to the the module to analyze
//
void
CompleteChecks::makeFSParameterCallsComplete(Module &M)
{
  Function *sc_fsparameter = M.getFunction("sc.fsparameter");

  if (sc_fsparameter == NULL)
    return;

  std::set<CallInst *> toComplete;

  //
  // Iterate over all uses of sc.fsparameter and discover which have a complete
  // pointer argument.
  //
  for (Function::use_iterator i = sc_fsparameter->use_begin();
       i != sc_fsparameter->use_end(); ++i) {
    CallInst *CI;
    CI = dyn_cast<CallInst>(*i);
    if (CI == 0 || CI->getCalledFunction() != sc_fsparameter)
      continue;

    //
    // Get the parent function to which this call belongs.
    //
    Function *P = CI->getParent()->getParent();
    Value *PtrOperand = CI->getOperand(2);
    
    DSNode *N = getDSNodeHandle(PtrOperand, P).getNode();

    if (N == 0                ||
        N->isExternalNode()   ||
        N->isIncompleteNode() ||
        N->isUnknownNode()    ||
        N->isPtrToIntNode()   ||
        N->isIntToPtrNode()) {
      continue;
    }

    toComplete.insert(CI);
  }

  //
  // Fill in a 1 for each call instruction that has a complete pointer
  // argument.
  //
  Type *int8      = Type::getInt8Ty(M.getContext());
  Constant *complete = ConstantInt::get(int8, 1);

  for (std::set<CallInst *>::iterator i = toComplete.begin();
       i != toComplete.end();
       ++i) {
    CallInst *CI = *i;
    CI->setOperand(4, complete);
  }

  return;
}

bool DSGraphStats::isNodeForValueUntyped(Value *V, unsigned Offset, const Function *F) {
  DSNodeHandle NH = getNodeHandleForValue(V);
  if(!NH.getNode()){
    return true;
  }
  else {
    DSNode *N = NH.getNode();
    if (N->isNodeCompletelyFolded()){
      ++NumFoldedAccess;
      return true;
    }
    if ( N->isExternalNode()){
      ++NumExternalAccesses;
      return true;
    }
    if ( N->isIncompleteNode()){
      ++NumIncompleteAccesses;
      return true;
    }
    if (N->isUnknownNode()){
      ++NumUnknownAccesses;
      return true;
    }
    if (N->isIntToPtrNode()){
      ++NumI2PAccesses;
      return true;
    }
    // it is a complete node, now check how many types are present
    int count = 0;
    unsigned offset = NH.getOffset() + Offset;
    if (N->type_begin() != N->type_end())
      for (DSNode::TyMapTy::const_iterator ii = N->type_begin(),
           ee = N->type_end(); ii != ee; ++ii) {
        if(ii->first != offset)
          continue;
        count += ii->second->size();
      }

    if (count ==0)
      ++NumTypeCount0Accesses;
    else if(count == 1)
      ++NumTypeCount1Accesses;
    else if(count == 2)
      ++NumTypeCount2Accesses;
    else if(count == 3)
      ++NumTypeCount3Accesses;
    else
      ++NumTypeCount4Accesses;
    DEBUG(assert(TS->isTypeSafe(V,F)));
  }
  return false;
}

void
AllButUnreachableFromMemoryHeuristic::AssignToPools (
                                          const DSNodeList_t &NodesToPA,
                                          Function *F, DSGraph* G,
                                          std::vector<OnePool> &ResultPools) {
  // Build a set of all nodes that are reachable from another node in the
  // graph.  Here we ignore scalar nodes that are only globals as they are
  // often global pointers to big arrays.
  std::set<const DSNode*> ReachableFromMemory;
  for (DSGraph::node_iterator I = G->node_begin(), E = G->node_end();
       I != E; ++I) {
    DSNode *N = I;
#if 0
    //
    // Ignore nodes that are just globals and not arrays.
    //
    if (N->isArray() || N->isHeapNode() || N->isAllocaNode() ||
        N->isUnknownNode())
#endif
    // If a node is marked, all children are too.
    if (!ReachableFromMemory.count(N)) {
      for (DSNode::iterator NI = N->begin(), E = N->end(); NI != E; ++NI) {
        //
        // Sometimes this results in a NULL DSNode.  Skip it if that is the
        // case.
        //
        if (!(*NI)) continue;

        //
        // Do a depth-first iteration over the DSGraph starting with this
        // child node.
        //
        for (df_ext_iterator<const DSNode*>
               DI = df_ext_begin(*NI, ReachableFromMemory),
               E = df_ext_end(*NI, ReachableFromMemory); DI != E; ++DI)
        /*empty*/;
      }
    }
  }

  // Only pool allocate a node if it is reachable from a memory object (itself
  // included).
  for (unsigned i = 0, e = NodesToPA.size(); i != e; ++i)
    if (ReachableFromMemory.count(NodesToPA[i]))
      ResultPools.push_back(OnePool(NodesToPA[i]));
}

//
// TODO
//
template<class dsa> bool
TypeSafety<dsa>::isFieldDisjoint (const GlobalValue * V, unsigned offset) {
  //
  // Get the DSNode for the specified value.
  //
  DSNodeHandle DH = getDSNodeHandle (V);
  DSNode *node = DH.getNode();
  //unsigned offset = DH.getOffset();
  DEBUG(errs() << " check fields overlap at: " << offset << "\n");

  //
  // If there is no DSNode, claim that it is not type safe.
  //
  if (DH.isNull()) {
    return false;
  }
  //
  // If the DSNode is completely folded, then we know for sure that it is not
  // type-safe.
  //
  if (node->isNodeCompletelyFolded())
    return false;

  //
  // If the memory object represented by this DSNode can be manipulated by
  // external code or DSA has otherwise not finished analyzing all operations
  // on it, declare it type-unsafe.
  //
  if (node->isExternalNode() || node->isIncompleteNode())
    return false;

  //
  // If the pointer to the memory object came from some source not understood
  // by DSA or somehow came from/escapes to the realm of integers, declare it
  // type-unsafe.
  //
  if (node->isUnknownNode() || node->isIntToPtrNode() || node->isPtrToIntNode()) {
    return false;
  }

  return !((NodeInfo[node])[offset]); 
}

//
// Function: makeCStdLibCallsComplete()
//
// Description:
//  Fills in completeness information for all calls of a given CStdLib function
//  assumed to be of the form:
//
//   pool_X(POOL *p1, ..., POOL *pN, void *a1, ..., void *aN, ..., uint8_t c);
//
//  Specifically, this function assumes that there are as many pointer arguments
//  to check as there are initial pool arguments, and the pointer arguments
//  follow the pool arguments in corresponding order. Also, it is assumed that
//  the final argument to the function is a byte sized bit vector.
//
//  This function fills in this final byte with a constant value whose ith
//  bit is set exactly when the ith pointer argument is complete.
//
// Inputs:
//
//  F            - A pointer to the CStdLib function appearing in the module
//                 (non-null).
//  PoolArgs     - The number of initial pool arguments for which a
//                 corresponding pointer value requires a completeness check
//                 (required to be at most 8).
//
void
CompleteChecks::makeCStdLibCallsComplete(Function *F, unsigned PoolArgs) {
  assert(F != 0 && "Null function argument!");

  assert(PoolArgs <= 8 && \
    "Only up to 8 arguments are supported by CStdLib completeness checks!");

  Value::use_iterator U = F->use_begin();
  Value::use_iterator E = F->use_end();

  //
  // Hold the call instructions that need changing.
  //
  typedef std::pair<CallInst *, uint8_t> VectorReplacement;
  std::set<VectorReplacement> callsToChange;

  Type *int8ty = Type::getInt8Ty(F->getContext());
  FunctionType *F_type = F->getFunctionType();

  //
  // Verify the type of the function is as expected.
  //
  // There should be as many pointer parameters to check for completeness
  // as there are pool parameters. The last parameter should be a byte.
  //
  assert(F_type->getNumParams() >= PoolArgs * 2 && \
    "Not enough arguments to transformed CStdLib function call!");
  for (unsigned arg = PoolArgs; arg < PoolArgs * 2; ++arg)
    assert(isa<PointerType>(F_type->getParamType(arg)) && \
      "Expected pointer argument to function!");

  //
  // This is the position of the vector operand in the call.
  //
  unsigned vect_position = F_type->getNumParams();

  assert(F_type->getParamType(vect_position - 1) == int8ty && \
    "Last parameter to the function should be a byte!");

  //
  // Iterate over all calls of the function in the module, computing the
  // vectors for each call as it is found.
  //
  for (; U != E; ++U) {
    CallInst *CI;
    if ((CI = dyn_cast<CallInst>(*U)) && \
      CI->getCalledValue()->stripPointerCasts() == F) {

      uint8_t vector = 0x0;

      //
      // Get the parent function to which this instruction belongs.
      //
      Function *P = CI->getParent()->getParent();

      //
      // Iterate over the pointer arguments that need completeness checking
      // and build the completeness vector.
      //
      for (unsigned arg = 0; arg < PoolArgs; ++arg) {
        bool complete = true;
        //
        // Go past all the pool arguments to get the pointer to check.
        //
        Value *V = CI->getOperand(1 + PoolArgs + arg);

        //
        // Check for completeness of the pointer using DSA and 
        // set the bit in the vector accordingly.
        //
        DSNode *N;
        if ((N = getDSNodeHandle(V, P).getNode()) &&
              (N->isExternalNode() || N->isIncompleteNode() ||
               N->isUnknownNode()  || N->isIntToPtrNode()   ||
               N->isPtrToIntNode()) ) {
//.........这里部分代码省略.........

//
// Method: findGlobalPoolNodes()
//
// Description:
//  This method finds DSNodes that are reachable from globals and that need a
//  pool.  The Automatic Pool Allocation transform will use the returned
//  information to build global pools for the DSNodes in question.
//
//  For efficiency, this method also determines which DSNodes should be in the
//  same pool.
//
// Outputs:
//  Nodes - The DSNodes that are both reachable from globals and which should
//          have global pools will be *added* to this container.
//
void
AllNodesHeuristic::findGlobalPoolNodes (DSNodeSet_t & Nodes) {
    // Get the globals graph for the program.
    DSGraph* GG = Graphs->getGlobalsGraph();

    //
    // Get all of the nodes reachable from globals.
    //
    DenseSet<const DSNode*> GlobalNodes;
    GetNodesReachableFromGlobals (GG, GlobalNodes);

    //
    // Create a global pool for each global DSNode.
    //
    for (DenseSet<const DSNode *>::iterator NI = GlobalNodes.begin();
            NI != GlobalNodes.end();
            ++NI) {
        const DSNode * N = *NI;
        PoolMap[N] = OnePool(N);
    }

    //
    // Now find all DSNodes belonging to function-local DSGraphs which are
    // mirrored in the globals graph.  These DSNodes require a global pool, too,
    // but must use the same pool as the one assigned to the corresponding global
    // DSNode.
    //
    for (Module::iterator F = M->begin(); F != M->end(); ++F) {
        //
        // Ignore functions that have no DSGraph.
        //
        if (!(Graphs->hasDSGraph(*F))) continue;

        //
        // Compute a mapping between local DSNodes and DSNodes in the globals
        // graph.
        //
        DSGraph* G = Graphs->getDSGraph(*F);
        DSGraph::NodeMapTy NodeMap;
        G->computeGToGGMapping (NodeMap);

        //
        // Scan through all DSNodes in the local graph.  If a local DSNode has a
        // corresponding DSNode in the globals graph that is reachable from a
        // global, then add the local DSNode to the set of DSNodes reachable from
        // a global.
        //
        DSGraph::node_iterator ni = G->node_begin();
        for (; ni != G->node_end(); ++ni) {
            DSNode * N = ni;
            DSNode * GGN = NodeMap[N].getNode();

            assert (!GGN || GlobalNodes.count (GGN));
            if (GGN && GlobalNodes.count (GGN))
                PoolMap[GGN].NodesInPool.push_back (N);
        }
    }

    //
    // Scan through all the local graphs looking for DSNodes which may be
    // reachable by a global.  These nodes may not end up in the globals graph
    // because of the fact that DSA doesn't actually know what is happening to
    // them.
    //
    // FIXME: I believe this code causes a condition in which a local DSNode is
    //        given a local pool in one function but not in other functions.
    //        Someone needs to investigate whether DSA is being consistent here,
    //        and if not, if that inconsistency is correct.
    //
#if 0
    for (Module::iterator F = M->begin(); F != M->end(); ++F) {
        if (F->isDeclaration()) continue;
        DSGraph* G = Graphs->getDSGraph(*F);
        for (DSGraph::node_iterator I = G->node_begin(), E = G->node_end();
                I != E;
                ++I) {
            DSNode * Node = I;
            if (Node->isExternalNode() || Node->isUnknownNode()) {
                GlobalNodes.insert (Node);
            }
        }
    }
#endif

    //
//.........这里部分代码省略.........