vsavchenko added inline comments.
================
Comment at:
clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.cpp:953-957
+ // Let's traverse...
+ for (const ExplodedNode *N = ExprNode;
+ // ...all the nodes corresponding to the given expression...
+ N != nullptr && N->getStmtForDiagnostics() == E;
+ N = N->getFirstPred()) {
----------------
Szelethus wrote:
> vsavchenko wrote:
> > NoQ wrote:
> > > I guess this part should ultimately be written in one place, eg.
> > > `ExplodedNode::findTag()` or something like that.
> > >
> > > I'd also really like to explore the possibility to further limit the
> > > variety of nodes traversed here. What nodes are typically traversed here?
> > > Is it checker-tagged nodes or is it purge dead symbol nodes or something
> > > else?
> > Yes, `ExplodedNode::findTag()` sounds like a great idea!
> >
> > I mean it is hard to tell without calculating statistics right here and
> > running it on a bunch of projects. However, it is always possible to write
> > the code that will have it the other way. My take on it is that it is
> > probably a mix of things.
> >
> > I'd also prefer to traverse less, do you have any specific ideas here?
> > I'd also really like to explore the possibility to further limit the
> > variety of nodes traversed here. What nodes are typically traversed here?
> > Is it checker-tagged nodes or is it purge dead symbol nodes or something
> > else?
>
> Is there something I'm not seeing here? Trackers basically ascend //a// path
> from the error node to at most the root of the ExplodedGraph (not the trimmed
> version, as `Tracker::track()` is called before any of that process happens),
> so its not much slower than `trackExpressionValue`, right?
>
> Or does this, and likely many other future handlers run such a loop more
> often then what I imagine?
>
>
Essentially, yes. `trackExpressionValue` (and `Tracker::track`) ascend the
graph searching for a node where the give expression is evaluated. The problem
here is that whenever we ask to track some expression, not only
`trackExpressionValue` will do its traversal (much longer), but also this
handler will do its (shorter). It would be better not to do this altogether,
but I personally don't see any solutions how we can cut on this part.
At the same time, I don't think that it is performance critical, considering
that the part of the graph where `N->getStmtForDiagnostics() == E` is small.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D104136/new/
https://reviews.llvm.org/D104136
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