[cfe-dev] [analyzer] Modeling a function with an out parameter pointer in check::PostCall

[Artem Dergachev via cfe-dev]

On 6/16/20 3:56 AM, philip.chimento at gmail.com wrote:
> On Sun, Jun 14, 2020 at 2:05 AM Artem Dergachev <noqnoqneo at gmail.com 
> <mailto:noqnoqneo at gmail.com>> wrote:
>
>     > How do I get the SVal for the memory pointed to by
>     CallEvent::getArgSVal(0)?
>
>     ProgramState::getSVal (the overload that accepts the location/region).
>
>
> Thanks, that was it. I would never have thought that SVal -> 
> SVal::getAsRegion() -> ProgramState::getSVal() would have ended up 
> with anything but the original SVal, but there it is!
>
>     Generally i recommend checking out a few links at the bottom of
>     http://clang-analyzer.llvm.org/checker_dev_manual.html
>
>
> Speaking of that... would you be interested in merging my PR 
> https://github.com/haoNoQ/clang-analyzer-guide/pull/5 and some of the 
> other open PRs on the handbook, and releasing a new version? Depending 
> on how much of a hassle it is, I might be interested to make it 
> publish as HTML to GitHub Pages automatically so you wouldn't have to 
> release PDFs...

Ugh, there are countless more outdated paragraphs in there. There are 
even bugs documented that had to be fixed rather than documented. I 
emitted it as an artifact that would have been created anyway at some 
point but i'm personally not planning to maintain it further because 
it's not the right way to do documentation (we'd rather have doxygen / 
rst documentation). Please feel free to fork but i'd much rather have it 
converted to into in-tree documentation (say, documentation in chapter 5 
could be torn into individual doxygen comments).

>     14.06.2020 12:05 AM, via cfe-dev wrote:
>>     Hi list,
>>
>>     I am writing a static analyzer checker and trying to model a
>>     function of the following type in check::PostCall:
>>
>>     void func(bool* outParam) {
>>         assert(outParam);
>>         *outParam = true;
>>     }
>>
>>     (in real life there are some other inputs that determine the
>>     value stored in the out parameter, and a return value indicating
>>     whether there was an error, but let's use this for the sake of a
>>     simple example)
>>
>>     Suppose I want my PostCall callback to store "true" in *outParam.
>>     Is this possible to achieve with ProgramState::BindExpr or
>>     ProgramState::bindLoc? How do I get the SVal for the memory
>>     pointed to by CallEvent::getArgSVal(0)?
>>
>>     I thought of "synthesizing" a UnaryOperator expression using
>>     UO_Deref on CallEvent::getArgExpr(0) and passing that to
>>     ProgramState::BindExpr, but it seems that getArgExpr returns a
>>     const Expr* and a non-const one is required to construct a
>>     UnaryOperator expression.
>>
>>     Best regards,
>>     -- 
>>     Philip
>>
>>     _______________________________________________
>>     cfe-dev mailing list
>>     cfe-dev at lists.llvm.org  <mailto:cfe-dev at lists.llvm.org>
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>
>
> Regards,
> -- 
> Philip

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