NoQ added inline comments.
================ Comment at: clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp:408-412 + SmallString<128> Msg; + llvm::raw_svector_ostream Out(Msg); + TagDetails.trackValidExpr(BR); + TagDetails.explainSmartPtrAction(Out); + return std::string(Out.str()); ---------------- vrnithinkumar wrote: > NoQ wrote: > > NoQ wrote: > > > vrnithinkumar wrote: > > > > NoQ wrote: > > > > > NoQ wrote: > > > > > > Ok, note that note tags are attached to nodes independently of bug > > > > > > reports; when the report is thrown, only then we know what are the > > > > > > smart pointers that should be explained. > > > > > > > > > > > > So there are two checks that you should do here: > > > > > > > > > > > > 1. Check that the bug report is emitted by your checker (eg., by > > > > > > comparing bug types). If not, don't add notes. > > > > > > > > > > > > 2. Check that the region about which the note speaks is related to > > > > > > your report (i.e., it's not a completely unrelated smart pointer). > > > > > > You can do that by marking the smart pointer as "interesting" > > > > > > (i.e., `PathSensitiveBugReport::markIntersting()`) when you emit > > > > > > the report, and then in the lambda you check whether the smart > > > > > > pointer is interesting before you emit a note. Additionally, you > > > > > > can carry over interestingness when smart pointers are copied. > > > > > > > > > > > > This is what i was trying to accomplish with this code snippet that > > > > > > i included in the examples in the other comment: > > > > > > ```lang=c++ > > > > > > if (&BR.getBugType() != &NullDereferenceBugType || > > > > > > !R->isInteresting()) > > > > > > return ""; > > > > > > ``` > > > > > (i strongly recommend having test cases for both of these issues) > > > > I was stuck on how to check the 2 cases from `SmartPtrModeling`. > > > > > > > > 1. I was not able to figure out how to access `NullDereferenceBugType` > > > > defined in the `SmartPtrChecker` in `SmartPtrModeling` to check > > > > `&BR.getBugType() != &NullDereferenceBugType`. Since > > > > `NullDereferenceBugType` is part of the `SmartPtrChecker` I could not > > > > access it from `PathSensitiveBugReport`. One way I figured out is to > > > > use `getCheckerName()` on BugType and compare the string. I feel this > > > > one as little hacky. > > > > > > > > > > > > 2. I got stuck on how will we implement the `!R->isInteresting()` in > > > > case of the bug report is added by some other checker on some other > > > > region. For below test case, bug report is added on a raw pointer by > > > > `CallAndMessageChecker` and the `!R->isInteresting()` will not satisfy > > > > and we will not be adding note tags where `unique_ptr` is released. I > > > > tried getting the LHS region for `A *AP = P.release();` assignment > > > > operation and check if the region is interesting but not sure whether > > > > its gonna work for some complex assignment cases. > > > > > > > > ``` > > > > void derefOnReleasedNullRawPtr() { > > > > std::unique_ptr<A> P; > > > > A *AP = P.release(); // expected-note {{'AP' initialized to a null > > > > pointer value}} > > > > // expected-note@-1 {{Smart pointer 'P' is released and set to null}} > > > > AP->foo(); // expected-warning {{Called C++ object pointer is null > > > > [core.CallAndMessage]}} > > > > // expected-note@-1{{Called C++ object pointer is null}} > > > > } > > > > ``` > > > > Since `NullDereferenceBugType` is part of the `SmartPtrChecker` I could > > > > not access it from `PathSensitiveBugReport`. > > > > > > You shouldn't be accessing it from the bug report, you should be > > > accessing it from the lambda. See the example code snippets in > > > D84600#inline-779418 > > > > > > > For below test case, bug report is added on a raw pointer by > > > > `CallAndMessageChecker` and the `!R->isInteresting()` will not satisfy > > > > and we will not be adding note tags where `unique_ptr` is released. > > > > > > That's an interesting question (no pun intended). The way i imagine this > > > working is: the note tag for `.release()` should try to figure out > > > whether the raw pointer is tracked and mark the smart pointer as > > > interesting based on that. If the raw pointer was a symbol that would > > > have been easy (either null dereference checker or > > > `trackExpressionValue()` could mark it as interesting). But for concrete > > > null pointer this won't work. > > > > > > Maybe we should consider introducing interesting expressions. I.e., when > > > `trackExpressionValue()` reaches the call-expression `P.release()`, it > > > has to stop there. But if it also marked the call-expression as > > > interesting, the note tag provided by the checker could read that > > > interestingness information and act upon it by marking the smart pointer > > > region as interesting. > > > That's an interesting question > > > > I'd rather make a separate commit for this endeavor because it sounds > > pretty nasty. > > You shouldn't be accessing it from the bug report, you should be accessing > > it from the lambda. See the example code snippets in D84600#inline-779418 > Sorry, I am still confused how will the lambda defined in the > `SmartPtrModeling` can capture the `NullDereferenceBugType` from > `SmartPtrChecker`? Lambda can capture anything that's available in its lexical context. For capturing a field of the surrounding class, i believe you should capture `this`. [[ https://github.com/llvm/llvm-project/blob/llvmorg-11-init/clang/lib/StaticAnalyzer/Checkers/MIGChecker.cpp#L214 | See how other checkers do that. ]] Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D84600/new/ https://reviews.llvm.org/D84600 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits