[cfe-dev] Clang Static Analyzer - tracking object value

[Gábor Kozár]

Hi,

I'm trying to write a custom checker that would look for transaction
objects being created and used, and would issue a warning when the success
of the transaction was not checked after commit.

I'm using checkPreCall, and I can successfully find when a transaction
object is constructed, and I add the tracking information, based on what
I've seen in StreamChecker.cpp:

if(call.getKind() == CE_CXXConstructor)
{
    auto callExpr = static_cast<const CallExpr*>(call.getOriginExpr());

    SValBuilder& svalBuilder = context.getSValBuilder();
    const LocationContext* locationContext =
context.getPredecessor()->getLocationContext();
    DefinedSVal createdTransactionObjVal =
llvm::cast<DefinedSVal>(svalBuilder.conjureSymbolVal(0, callExpr,
locationContext, context.blockCount()));
    programState = programState->BindExpr(callExpr,
context.getLocationContext(), createdTransactionObjVal);

    if(SymbolRef createdTransactionObjSymbol =
createdTransactionObjVal.getAsSymbol())
    {
        programState =
programState->set<TransactionStateMap>(createdTransactionObjSymbol,
TransactionState());
        context.addTransition(programState);
    }
    ...
}
...

So first, is there any easier way to access the symbolic value that is
created as the result of the constructor running? This seems like an
awfully complicated way of doing a simple task.

Next, my problem is with detecting when members of the transaction object
is called. I was trying to get the SymbolRef of the object whose member is
called:

const CXXInstanceCall* instanceCall =
llvm::dyn_cast<CXXInstanceCall>(&call);
...
SymbolRef transactionObjectSymbol =
instanceCall->getCXXThisVal().getAsSymbol();

But I find that this SymbolRef is always NULL. Why is that?

I also tried to work around with this:
SymbolRef transactionObjectSymbol = programState->getSVal(static_cast<const
CXXMemberCallExpr*>(instanceCall->getOriginExpr())->getImplicitObjectArgument(),
context.getLocationContext()).getAsSymbol();

But this doesn't work either.

What am I doing wrong?

Thanks!

Gabor
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20130429/f875b13e/attachment.html>