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Re: [csmith-dev] Generate two slightly different files

Additionally, since Csmith and Frama-C cooperate so well, a guess-and-check approach can work: instead of being careful in Csmith you instead generate whatever you like and then use Frama-C to verify absence of UB. 

John


On 4/29/16 6:49 PM, Xuejun Yang wrote:

Do you care about undefined behaviors? If not, you can add a pass after
Csmith generates the program (which basically is an AST), and before
prints it, that mutates one of the leaf nodes. Csmith has a GTAV
(generation time analysis & validation) that ensures the semantics of
the AST don't introduce undefined behaviors, if you are as careful as
Csmith, the mutation might come out fine.

-Xuejun

On Thu, Apr 28, 2016 at 8:37 AM, Christian Dietrich <dietrich@cs.fau.de
<mailto:dietrich@cs.fau.de>> wrote:

    Hi,

    I'm currently searching for a tool to generate two C files that
    are very similar. What do I mean by similar? The respective AST of the C
    files should only differ in one subexpression/type/etc. The difference
    should mimic the changes a developer does between two compiler
    invocations.

    Does csmith already allow such small alterations of its output? If so, I
    haven't seen an command line option for it. If it doesn't have this
    feature, could you give me a small hint where I should look to implement
    this behavior?

     chris
    --
    Christian Dietrich, M.Sc. (Research Staff)
    Computer Science 4 (Distributed Systems and Operating Systems)
    Friedrich-Alexander-Universität Erlangen-Nürnberg
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