[LLVMdev] Easiest way to collect dynamic Instruction execution counts?

[John Criswell]

Dear Stephen,

Kevin, one of my students, wrote an LLVM pass and run-time library that 
records and reports the number of dynamic LLVM instructions executed by 
a program.  You can find the code at 
https://github.com/hxy9243/priv_analysis.  The pass you want is in 
DynCount.cpp, and the code works with LLVM mainline.

One thing that this pass does is to alter the dynamic counts slightly to 
account for additional branches that our other transformation adds 
before analysis but will remove before code generation, so you may need 
to adjust the code slightly.

Regards,

John Criswell

On 5/28/15 8:08 AM, Stephen Thomas wrote:
> Hi,
>
> I'd like a simple and fast way to collect the number of times each 
> Instruction was executed in a given run of the application. As far as 
> I can tell, there are a number of approaches I can take:
>
> - Use PIN. This would require using DWARF debug info and Instruction 
> debug info to attempt to map instructions in the binary to 
> instructions in the bitcode; not 100% sure how accurate this will be.
>
> - Use llvm-prof. Two questions here. First, I've seen on Stack 
> Overflow 
> <https://urldefense.proofpoint.com/v2/url?u=https-3A__stackoverflow.com_questions_14617067_collecting-2Dllvm-2Dedge-2Dprofiling-2Dwith-2Dllvm-2Dprof&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=Mfk2qtn1LTDThVkh6-oGglNfMADXfJdty4_bhmuhMHA&m=HtoNbGGO3zcoVy6n3_8lqn7ZXiNnqiQKim27ER3buUQ&s=kf8XiNx6628Vrx9TCVI4rrnisNDMVf8ZcuKA6V0udhE&e=> 
> an option to `opt` called `--insert-edge-profiling`. However, that 
> option doesn't seem to be available in 3.6? Second, it appears that 
> such profiling only records execution counts at the Function level, 
> not at the individual Instruction level. Is that correct?
>
> - Write a new tool similar to AddressSanitizer. 
> <https://urldefense.proofpoint.com/v2/url?u=http-3A__clang.llvm.org_docs_AddressSanitizer.html&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=Mfk2qtn1LTDThVkh6-oGglNfMADXfJdty4_bhmuhMHA&m=HtoNbGGO3zcoVy6n3_8lqn7ZXiNnqiQKim27ER3buUQ&s=B48ymTvL2IOafrTkfbB7YJl2y6OdfQtG7_I7dfiuNPU&e=> This 
> may work, but seems like overkill.
>
> Is there an easier way to achieve my goal that I'm missing?
>
> Thanks,
> Steve
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev


-- 
John Criswell
Assistant Professor
Department of Computer Science, University of Rochester
http://www.cs.rochester.edu/u/criswell

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150528/2a21f4c7/attachment.html>