[cfe-dev] Question on LiveVariables analysis

[Georg Altmann]

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On 11.10.2011 05:56, Anna Zaks wrote:
> Most likely there is some issue with the way you build the analysis
> in your code; you should probably look at other uses of 
> UninitializedVariables to see what you are missing. Also, try to
> find out at which step the first symptoms of the problem occur -
> for example, do you get a CFG different from what you see when
> dumping the CFG with a debug checker? (See the command from Ted's
> reply below.)
> 
> I noticed that you do not pass CFGBuildOptions when constructing 
> the AnalysisContext. Here is some code from
> AnalysisBasedWarnings.cpp, which implies that you might need to
> request linearized CFG. // Unreachable code analysis requires a
> linearized CFG. AC.getCFGBuildOptions().setAllAlwaysAdd();

Thank you! That just made my day!

Can anybody elaborate or give a pointer on what is meant by
a linearized CFG in this case?
I found this paper [1] which contains some info on CFG linearization.

Which algorithm is implemented for LiveVariables and CFG linearization
in clang static analyzer? Any pointers?

Regards,
Georg


[1]
paper: http://compilers.cs.uni-saarland.de/papers/karrenberg_opencl.pdf
DOI paper: http://dx.doi.org/10.1007/978-3-642-28652-0_1
slides: http://llvm.org/devmtg/2012-04-12/Slides/Ralf_Karrenberg.pdf

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