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

[Bruce Hoult]

Machine instructions, yes. You didn't say bitcode instruction.

Though it amounts to the same thing, as all instructions in the same basic
block have the same execution count and the basic blocks should correspond.

On Thu, May 28, 2015 at 5:18 PM, Stephen Thomas <
stephen.warner.thomas at gmail.com> wrote:

> 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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