//
// 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;
}
//
// 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;
}
//
// 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()) ) {
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;
}
