llvm dev - Mar 2016 - [GSoC] First draft project proposal; IR level interpreter debugger

On 3/25/16 11:58 AM, Janek van Oirschot via llvm-dev
wrote:
> On Fri, Mar 25, 2016 at 12:45 PM, Tobias Grosser <tobias at
grosser.es> wrote:
>> On 03/25/2016 03:28 AM, Philip Reames via llvm-dev wrote:
>>>
>>> I've scanned over your proposal, but am not quite sure I
understand your
>>> objective.  Is your intent to be able to step through IR source in
a
>>> debugger and inspect intermediate state?
>
> Yes, that is what I had in mind with this proposal.
>
>>> If so, you may consider
>>> whether "simply" inserting debug metatadata into your IR
which describes
>>> the IR source, and then compiling it gives you your desired result.
>>
>>
>> A pass that does precisely this has been contributed by someone from
Intel
>> at some point but got removed later on for reasons I don't recall.
>> It might be worth to scan the archives.
>>
>
> Thanks for your response, I have searched in archives and I think I
> found some references to what you're talking about (DebugIR?). Though,
> I haven't been able to find the reason as to why it was removed. My
> concern now is whether this GSoC project has become obsolete because
> of this.
>
> I'll continue trying to find the reason why this was removed.
IIRC, it was removed because it was buggy, and not well maintained.


Jon
>
> Kind regards,
> Janek
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
-- 
Jon Roelofs
jonathan at codesourcery.com
CodeSourcery / Mentor Embedded

On 03/25/2016 11:00 AM, Jonathan Roelofs via llvm-dev
wrote:
>
>
> On 3/25/16 11:58 AM, Janek van Oirschot via llvm-dev wrote:
>> On Fri, Mar 25, 2016 at 12:45 PM, Tobias Grosser <tobias at
grosser.es>
>> wrote:
>>> On 03/25/2016 03:28 AM, Philip Reames via llvm-dev wrote:
>>>>
>>>> I've scanned over your proposal, but am not quite sure I
understand
>>>> your
>>>> objective.  Is your intent to be able to step through IR source
in a
>>>> debugger and inspect intermediate state?
>>
>> Yes, that is what I had in mind with this proposal.
>>
>>>> If so, you may consider
>>>> whether "simply" inserting debug metatadata into your
IR which
>>>> describes
>>>> the IR source, and then compiling it gives you your desired
result.
>>>
>>>
>>> A pass that does precisely this has been contributed by someone
from
>>> Intel
>>> at some point but got removed later on for reasons I don't
recall.
>>> It might be worth to scan the archives.
>>>
>>
>> Thanks for your response, I have searched in archives and I think I
>> found some references to what you're talking about (DebugIR?).
Though,
>> I haven't been able to find the reason as to why it was removed. My
>> concern now is whether this GSoC project has become obsolete because
>> of this.
>>
>> I'll continue trying to find the reason why this was removed.
>
> IIRC, it was removed because it was buggy, and not well maintained.
I believe it was also blocking work on one of the debug info refactoring 
projects.

Resurrecting this pass, updating it to modern standards, adding good 
tests, and getting it back in tree could be valuable
project.
>
>
> Jon
>
>>
>> Kind regards,
>> Janek
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>

On Fri, Mar 25, 2016 at 7:24 PM, Philip Reames
<listmail at philipreames.com> wrote:
>
> Resurrecting this pass, updating it to modern standards, adding good tests,
> and getting it back in tree could be valuable project.
Even though it's too late to make adjustments to the GSoC proposals,
this sounds like the best methodology for debugging IR. If I get
accepted I'd like to look into this instead of implementing IR
debugging in the interpreter.

Kind regards,
Janek