Exemplo n.º 1
0
//
// Method: getLocalPoolNodes()
//
// Description:
//  For a given function, determine which DSNodes for that function should have
//  local pools created for them.
//
void
Heuristic::getLocalPoolNodes (const Function & F, DSNodeList_t & Nodes) {
  //
  // Get the DSGraph of the specified function.  If the DSGraph has no nodes,
  // then there is nothing we need to do.
  //
  DSGraph* G = Graphs->getDSGraph(F);
  if (G->node_begin() == G->node_end()) return;

  //
  // Calculate which DSNodes are reachable from globals.  If a node is reachable
  // from a global, we will create a global pool for it, so no argument passage
  // is required.
  Graphs->getGlobalsGraph();

  // Map all node reachable from this global to the corresponding nodes in
  // the globals graph.
  DSGraph::NodeMapTy GlobalsGraphNodeMapping;
  G->computeGToGGMapping(GlobalsGraphNodeMapping);

  //
  // Loop over all of the nodes which are non-escaping, adding pool-allocatable
  // ones to the NodesToPA vector.  In other words, scan over the DSGraph and
  // find nodes for which a new pool must be created within this function.
  //
  for (DSGraph::node_iterator I = G->node_begin(), E = G->node_end();
       I != E;
       ++I){
    // Get the DSNode and, if applicable, its mirror in the globals graph
    DSNode * N   = I;
    DSNode * GGN = GlobalsGraphNodeMapping[N].getNode();

    //
    // Only the following nodes are pool allocated:
    //  1) Local Heap nodes
    //  2) Nodes which are mirrored in the globals graph and, in the globals
    //     graph, are heap nodes.
    //
    if ((N->isHeapNode()) || (GGN && GGN->isHeapNode())) {
      if (!(GlobalPoolNodes.count (N) || GlobalPoolNodes.count (GGN))) {
        // Otherwise, if it was not passed in from outside the function, it must
        // be a local pool!
        assert((!N->isGlobalNode() || N->isPtrToIntNode()) && "Should be in global mapping!");
        if(!N->isPtrToIntNode()) {
          Nodes.push_back (N);
        }
      }
    }
  }

  return;
}
Exemplo n.º 2
0
//
// 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;
}
Exemplo n.º 3
0
//
// 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]); 
}
Exemplo n.º 4
0
//
// 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()) ) {
            complete = false;
        }

        if (complete)
          vector |= (1 << arg);
      }

      //
      // Add the instruction and vector to the set of instructions to change.
      //
      callsToChange.insert(VectorReplacement(CI, vector));
    }
  }


  //
  // Iterate over all call instructions that need changing, modifying the
  // final operand of the call to hold the bit vector value.
  //
  std::set<VectorReplacement>::iterator change = callsToChange.begin();
  std::set<VectorReplacement>::iterator change_end = callsToChange.end();

  while (change != change_end) {
    Constant *vect_value = ConstantInt::get(int8ty, change->second);
    change->first->setOperand(vect_position, vect_value);
    ++change;
  }

  return;

}