void GraphBuilder::visitIntToPtrInst(IntToPtrInst &I) {
DSNode *N = createNode();
if(I.hasOneUse()) {
if(isa<ICmpInst>(*(I.use_begin()))) {
NumBoringIntToPtr++;
return;
}
} else {
N->setIntToPtrMarker();
N->setUnknownMarker();
}
setDestTo(I, N);
}
///
/// getValueDest - Return the DSNode that the actual value points to.
///
DSNodeHandle GraphBuilder::getValueDest(Value* V) {
if (isa<Constant>(V) && cast<Constant>(V)->isNullValue())
return 0; // Null doesn't point to anything, don't add to ScalarMap!
DSNodeHandle &NH = G.getNodeForValue(V);
if (!NH.isNull())
return NH; // Already have a node? Just return it...
// Otherwise we need to create a new node to point to.
// Check first for constant expressions that must be traversed to
// extract the actual value.
DSNode* N;
if (Function * F = dyn_cast<Function > (V)) {
// Create a new global node for this function.
N = createNode();
N->addFunction(F);
if (F->isDeclaration())
N->setExternFuncMarker();
} else if (GlobalValue * GV = dyn_cast<GlobalValue > (V)) {
// Create a new global node for this global variable.
N = createNode();
N->addGlobal(GV);
if (GV->isDeclaration())
N->setExternGlobalMarker();
} else if (Constant *C = dyn_cast<Constant>(V)) {
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
if (CE->isCast()) {
if (isa<PointerType>(CE->getOperand(0)->getType()))
NH = getValueDest(CE->getOperand(0));
else
NH = createNode()->setUnknownMarker();
} else if (CE->getOpcode() == Instruction::GetElementPtr) {
visitGetElementPtrInst(*CE);
assert(G.hasNodeForValue(CE) && "GEP didn't get processed right?");
NH = G.getNodeForValue(CE);
} else {
// This returns a conservative unknown node for any unhandled ConstExpr
NH = createNode()->setUnknownMarker();
}
if (NH.isNull()) { // (getelementptr null, X) returns null
G.eraseNodeForValue(V);
return 0;
}
return NH;
} else if (isa<UndefValue>(C)) {
G.eraseNodeForValue(V);
return 0;
} else if (isa<GlobalAlias>(C)) {
// XXX: Need more investigation
// According to Andrew, DSA is broken on global aliasing, since it does
// not handle the aliases of parameters correctly. Here is only a quick
// fix for some special cases.
NH = getValueDest(cast<GlobalAlias>(C)->getAliasee());
return NH;
} else if (isa<BlockAddress>(C)) {
//
// FIXME: This may not be quite right; we should probably add a
// BlockAddress flag to the DSNode instead of using the unknown flag.
//
N = createNode();
N->setUnknownMarker();
} else {
errs() << "Unknown constant: " << *C << "\n";
assert(0 && "Unknown constant type!");
}
N = createNode(); // just create a shadow node
} else {
// Otherwise just create a shadow node
N = createNode();
}
NH.setTo(N, 0); // Remember that we are pointing to it...
return NH;
}