llvm dev - May 2020 - RFC: throw2goto exception optimization

Yes I'm looking for either community approval or reasons I might be barking
up the wrong tree :) Maybe someone else explored this idea and there's some
big roadblock.  I would like to contribute myself, and there may be others
like Emil who want to help.  I just wanted to let you all know what I want
to optimize since I've never contributed to clang before (sorry I don't
have better ideas on implementation strategy yet being unfamiliar with the
codebase.)

On Thu, May 21, 2020, 11:50 AM David Blaikie <dblaikie at gmail.com>
wrote:
> (re: official proposal numbers: there are none)
>
> What sort of feedback are you looking for on this? It doesn't seem to
be a
> proposal (at least in the way that they usually appear/are discussed in the
> LLVM community) - it sounds like "it'd be nice if compilers did
<x>"
> without any suggestion of how that might be achieved, or who would do the
> work to make that possible. Are you asking the LLVM community for approval
> for this direction so you can start contributing patches to implement it?
> Even that's going to probably require some amount of suggestion about,
> broadly, how this would be implemented - to get a better understanding of
> the cost/benefit - how invasive such a change would be, etc.
>
> - Dave
>
> On Wed, May 20, 2020 at 8:09 PM Jeff Linahan via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> Hello again LLVM devs,
>>
>> Here's the request for comments on the throw2goto exception
optimization
>> project.  (This is my first one, I don't know who gives out the
official
>> numbers for proposals :))
>>
>> Jeff
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-d
>> <https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev>
>>
>
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On Thu, May 21, 2020 at 3:02 PM Jeff Linahan <jeff.linahan at gmail.com>
wrote:
> Yes I'm looking for either community approval or reasons I might be
> barking up the wrong tree :) Maybe someone else explored this idea and
> there's some big roadblock.  I would like to contribute myself, and
there
> may be others like Emil who want to help.  I just wanted to let you all
> know what I want to optimize since I've never contributed to clang
before
> (sorry I don't have better ideas on implementation strategy yet being
> unfamiliar with the codebase.)
>
Fair enough - Richard Smith might be able to chime in with some more
perspective here. Guessing it'll come down to probably doing a fair amount
of work out of tree to demonstrate/figure out the structure/impact/etc &
maybe some sense of benefit to see if it's worth adding whatever the
complexity is to the compiler.

>
> On Thu, May 21, 2020, 11:50 AM David Blaikie <dblaikie at gmail.com>
wrote:
>
>> (re: official proposal numbers: there are none)
>>
>> What sort of feedback are you looking for on this? It doesn't seem
to be
>> a proposal (at least in the way that they usually appear/are discussed
in
>> the LLVM community) - it sounds like "it'd be nice if
compilers did <x>"
>> without any suggestion of how that might be achieved, or who would do
the
>> work to make that possible. Are you asking the LLVM community for
approval
>> for this direction so you can start contributing patches to implement
it?
>> Even that's going to probably require some amount of suggestion
about,
>> broadly, how this would be implemented - to get a better understanding
of
>> the cost/benefit - how invasive such a change would be, etc.
>>
>> - Dave
>>
>> On Wed, May 20, 2020 at 8:09 PM Jeff Linahan via llvm-dev <
>> llvm-dev at lists.llvm.org> wrote:
>>
>>> Hello again LLVM devs,
>>>
>>> Here's the request for comments on the throw2goto exception
optimization
>>> project.  (This is my first one, I don't know who gives out the
official
>>> numbers for proposals :))
>>>
>>> Jeff
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-d
>>> <https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev>
>>>
>>
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Sounds good, thanks for the feedback.  I was hoping it would just be a new
pass. :) (Arthur found the paragraph on g() calling std::terminate() is
incorrect, that needs to be rewritten when I understand the EH mechanisms
better.)

On Thu, May 21, 2020, 6:44 PM David Blaikie <dblaikie at gmail.com> wrote:
> On Thu, May 21, 2020 at 3:02 PM Jeff Linahan <jeff.linahan at
gmail.com>
> wrote:
>
>> Yes I'm looking for either community approval or reasons I might be
>> barking up the wrong tree :) Maybe someone else explored this idea and
>> there's some big roadblock.  I would like to contribute myself, and
there
>> may be others like Emil who want to help.  I just wanted to let you all
>> know what I want to optimize since I've never contributed to clang
before
>> (sorry I don't have better ideas on implementation strategy yet
being
>> unfamiliar with the codebase.)
>>
>
> Fair enough - Richard Smith might be able to chime in with some more
> perspective here. Guessing it'll come down to probably doing a fair
amount
> of work out of tree to demonstrate/figure out the structure/impact/etc
&
> maybe some sense of benefit to see if it's worth adding whatever the
> complexity is to the compiler.
>
>
>>
>> On Thu, May 21, 2020, 11:50 AM David Blaikie <dblaikie at
gmail.com> wrote:
>>
>>> (re: official proposal numbers: there are none)
>>>
>>> What sort of feedback are you looking for on this? It doesn't
seem to be
>>> a proposal (at least in the way that they usually appear/are
discussed in
>>> the LLVM community) - it sounds like "it'd be nice if
compilers did <x>"
>>> without any suggestion of how that might be achieved, or who would
do the
>>> work to make that possible. Are you asking the LLVM community for
approval
>>> for this direction so you can start contributing patches to
implement it?
>>> Even that's going to probably require some amount of suggestion
about,
>>> broadly, how this would be implemented - to get a better
understanding of
>>> the cost/benefit - how invasive such a change would be, etc.
>>>
>>> - Dave
>>>
>>> On Wed, May 20, 2020 at 8:09 PM Jeff Linahan via llvm-dev <
>>> llvm-dev at lists.llvm.org> wrote:
>>>
>>>> Hello again LLVM devs,
>>>>
>>>> Here's the request for comments on the throw2goto exception
>>>> optimization project.  (This is my first one, I don't know
who gives out
>>>> the official numbers for proposals :))
>>>>
>>>> Jeff
>>>> _______________________________________________
>>>> LLVM Developers mailing list
>>>> llvm-dev at lists.llvm.org
>>>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-d
>>>>
<https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev>
>>>>
>>>
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