[llvm-dev] llvm dynamic execution trace

Ammar Naqvi via llvm-dev llvm-dev at lists.llvm.org
Tue May 3 22:10:01 PDT 2016


Hi Dean, thank you for the response!

I'm a newbie to LLVM, a student working on an LLVM project so I'm not quite
sure of what you're suggesting, please excuse my naivety.

To clarify there used to exist this
http://llvm.org/releases/1.0/docs/CommandGuide/lli.html where you could
type "lli -trace 'filename.bc' and you would get a dump of the dynamic
excutiion trace.

  I need something like:
 to record the execution (statement/instruction) trace of a program. For
example, a C program is like this:

1:    sum = 0;
2:    for(i = 0; i < 2; i++)
3:        sum += i;
4:    printf("%d", sum);

    The execution trace would be something like 1->2->3->2->3->2->4.

Is there some way of achieving this, this was possible in previous verions
of LLVM <2.6 i believe; I need guidance of replicating this on the newer
version(using 3.8).

On 3 May 2016 at 21:18, Dean Michael Berris <dberris at google.com> wrote:

> Hi Ammar,
>
> I'm not sure about lli, but recently I sent an RFC for XRay, which does a
> combination of compiler-inserted instrumentation points and a runtime
> library that will allow for enabling these instrumentation points. Those
> could be used to log/trace function calls.
>
> I'm currently working on getting that into LLVM, Clang, and compiler-rt
> among other things.
>
> Does that help?
>
> PS. More information in the whitepaper (
> https://research.google.com/pubs/pub45287.html) we recently published.
>
> On Wed, May 4, 2016 at 2:05 PM Ammar Naqvi via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> hi everyone,
>>
>> I'm trying to get something like the lli - trace functionality that has
>> been deprecated.
>>
>> I need the same thing that the trace command was doing i. e. the dynamic
>> execution trace,  any idea on what it has moved to if it still exists or
>> how to implement it?
>>
>> Best Regards,
>> Ammar Naqvi
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>
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