[llvm-dev] GSoC19: Debug Info should have no effect on codegen

[Greg Bedwell via llvm-dev]

I raised an example bug here:
https://bugs.llvm.org/show_bug.cgi?id=40969
Let me know if you have any trouble reproducing it from the description
there.  Hopefully you should just be able to build it for x86_64 with and
without -g specified and see that we get a difference in code generation.

I essentially did what Jessica suggested above, although instead of the
LLVM test suite I used one of our internal test suites and instead of using
the compare.py script I used check_cfc which turns any differences into
compilation errors, which also has the useful property of making it trivial
to reduce very large test cases (I think this one started out in the 200
KLOC kind of range) into something more manageable using tools such as
C-Reduce ( https://embed.cs.utah.edu/creduce/ ).

-Greg

On Tue, 5 Mar 2019 at 18:19, Greg Bedwell <gregbedwell at gmail.com> wrote:

> We've got a meta-bug for these sorts of issues here:
> https://bugs.llvm.org/show_bug.cgi?id=37728
> You might also be interested in this presentation from a few years back:
> https://llvm.org/devmtg/2015-04/slides/Verifying_code_gen_dash_g_final.pdf
>
> I've just set off a test case reduction of a case I ran into on one of our
> internal test suites using the check_cfc tool so hopefully I can upload it
> as an example bug, attached to the metabug above once that's complete.
>
> On Tue, 5 Mar 2019 at 15:54, Mohamed Ali via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> Dear all,
>>
>> My name is Mohamed and I am a first year computer science masters
>> student. I am writing this email because I am interested in the project
>> idea "Debug Info Should have no effect on codegen". So far I have built
>> llvm and clang and I was trying to reproduce the problem on simple c++
>> programs but I can't. Being specific this are the steps I am doing:
>>
>> $ clang -g test.cc
>>> $ llvm-objdump -d a.out > with_debug
>>> $ clang  test.cc
>>> $ llvm-objdump -d a.out > no_debug
>>> $ vimdiff with_debug no_debug
>>
>>
>> I still can't reproduce the problem. In the expected results of the
>> project you mentioned that there are already failing test cases. Can you
>> please point me in to these cases?
>> Finally, I would like to ask whether there is some qualification task I
>> should do or I have to fix some of the open tickets? Would you please point
>> me to such tasks or suggest some tickets/bugs that I can start working on?
>>
>> Regards,
>> Mohamed
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>
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