/// Infer nonnull attributes for the arguments at the specified callsite.
static bool processCallSite(CallSite CS, LazyValueInfo *LVI) {
SmallVector<unsigned, 4> ArgNos;
unsigned ArgNo = 0;
if (auto *II = dyn_cast<IntrinsicInst>(CS.getInstruction())) {
if (willNotOverflow(II, LVI)) {
processOverflowIntrinsic(II);
return true;
}
}
for (Value *V : CS.args()) {
PointerType *Type = dyn_cast<PointerType>(V->getType());
// Try to mark pointer typed parameters as non-null. We skip the
// relatively expensive analysis for constants which are obviously either
// null or non-null to start with.
if (Type && !CS.paramHasAttr(ArgNo, Attribute::NonNull) &&
!isa<Constant>(V) &&
LVI->getPredicateAt(ICmpInst::ICMP_EQ, V,
ConstantPointerNull::get(Type),
CS.getInstruction()) == LazyValueInfo::False)
ArgNos.push_back(ArgNo);
ArgNo++;
}
assert(ArgNo == CS.arg_size() && "sanity check");
if (ArgNos.empty())
return false;
AttributeList AS = CS.getAttributes();
LLVMContext &Ctx = CS.getInstruction()->getContext();
AS = AS.addParamAttribute(Ctx, ArgNos,
Attribute::get(Ctx, Attribute::NonNull));
CS.setAttributes(AS);
return true;
}
