Hello,
I am Abhinav Tripathi, B.Tech 3rd Year student from IIT Indore, India. I was looking on the projects ideas page of llvm and saw that I could also propose to work on the SAFECode Open projects. As I found no mailing list on their site, I am sending this message here. Please redirect me to some other list, if required.
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I found most of the projects quite alluring as I have been working on a similar project (in terms of tasks) since the last GSoC. It is CPPSharp (https://github.com/genuinelucifer/CppSharp).
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The ones that I found most interesting were:
1 - Improve Static Array Bounds Checking – Because I have done a lot of array related tasks while writing marshalling code for CppSharp. I think I can really contribute into this project.
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2 - Create a simpler CompleteChecks pass – Although I admit, I didn’t quite understand what simpler would mean here. But it seems fairly challenging (if it’s regarding optimisation) or involving understanding of a large part of codebase (in which case too it intrigues me). I would love to work on this one too.
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If the mentor(s) or anyone else would like to state a few proficiency tests to prove my aptness for the projects, I would love to submit a couple of patches before applying for GSoC.
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Regards,
Abhinav
The most useful project for SAFECode right now is to update its code to work with either LLVM 3.7 or LLVM 3.8. I had a student work on this last summer (code is at ), but it needs to be completed and tested. On my end, I’m interested in getting SAFECode dusted off because I’d like to use it for research projects that need to attach metadata to memory objects. Until SAFECode is updated to a newer version of LLVM, its utility is pretty limited, and any projects to enhance it will basically require that it be updated to a newer version of LLVM. Static Array Bounds Checking requires that you understand static analysis. Multiple static analysis methods are applicable: range analysis, integer linear programming, SMT solvers, etc. For a successful proposal for static array bounds checking, you should know which algorithm you will implement and be able to explain why you think it will work well. For SAFECode, the algorithm must be sound with respect to two’s complement arithmetic (i.e., the algorithm must take into account that integers in C can experience underflow or overflow when used in arithmetic). The CompleteChecks pass currently uses the DSA points-to analysis (which is large and complicated). There are simpler analyses that one could do to determine whether a memory object is read or written by external code. For example, a simple intra-procedural analysis could determine if a memory object is allocated and only used by the current function, and a simple inter-procedural analysis could create a very simple heap abstraction and perform data-flow analysis on the pointers contained within heap objects to determine if they are influenced by external library code. Basically, there are some simple quick analyses that would be imprecise but could probably find memory objects that are not manipulated by external code. I think the only proficiency test is whether you can show in your proposal that you have the necessary programming skills and background information to be able to do what you propose. In both of these projects, if you’re not familiar with static analysis (e.g., Kam/Ulman data-flow analysis), then you’re likely not ready for these projects. For the two projects you mentioned, I would also expect existing familiarity with LLVM. Again, though, the best project is probably to update SAFECode to a modern version of LLVM. Regards, John Criswell
Sorry, forgot to add the mailing list…
Hi,
Thanks for the detailed response.
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