llvm dev - May 2015 - [LLVMdev] Easiest way to collect dynamic Instruction execution counts?

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://stackoverflow.com/questions/14617067/collecting-llvm-edge-profiling-with-llvm-prof>
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.
<http://clang.llvm.org/docs/AddressSanitizer.html> This may work, but
seems
like overkill.

Is there an easier way to achieve my goal that I'm missing?

Thanks,
Steve
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That seems like a job for valgrind?

Assuming you're on a supported platform, but these days that includes all
the common Mac/Linux/Android platforms except ARM64.

On Thu, May 28, 2015 at 4:08 PM, Stephen Thomas <
stephen.warner.thomas at gmail.com> 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
>
>
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Bruce,

Can valgrind give me the execution counts for each Instruction in the LLVM
bitcode?

Thanks,
Steve

On Thu, May 28, 2015 at 9:34 AM, Bruce Hoult <bruce at hoult.org> wrote:
> That seems like a job for valgrind?
>
> Assuming you're on a supported platform, but these days that includes
all
> the common Mac/Linux/Android platforms except ARM64.
>
> On Thu, May 28, 2015 at 4:08 PM, Stephen Thomas <
> stephen.warner.thomas at gmail.com> 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
>>
>>
>
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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

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