llvm dev - Oct 2017 - 'cl::opt' and range checking

Hi LLVM-Devs,

The LLVM 'cl::opt' templates are really useful, and provide a lot of
flexibility.  But I don't see any support for ranged options.  What I would
like is to have an option which is an integer type, and to restrict the set of
values provided to a simple upper and lower bound, for example between 10 and
2000.

Is there a way of expressing this with the 'cl::opt' templates, or do I
have to explicitly range check the values in my own code and issue a diagnostic
or clamp as appropriate?

Thanks,

            MartinO

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I don't think this is currently supported by `cl::opt`, but you can
probably write your own adapter class so that you could write
`cl::opt<cl::range<int,3,7>>`.

You'd just need to write a parser for `cl::range` and do the checking in
there.  Seems like a useful patch, I've needed this from time to time
myself.

On Tue, Oct 3, 2017 at 6:24 AM ORiordan, Martin via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hi LLVM-Devs,
>
>
>
> The LLVM ‘cl::opt’ templates are really useful, and provide a lot of
> flexibility.  But I don’t see any support for ranged options.  What I would
> like is to have an option which is an integer type, and to restrict the set
> of values provided to a simple upper and lower bound, for example between
> 10 and 2000.
>
>
>
> Is there a way of expressing this with the ‘cl::opt’ templates, or do I
> have to explicitly range check the values in my own code and issue a
> diagnostic or clamp as appropriate?
>
>
>
> Thanks,
>
>
>
>             MartinO
>
>
>
> --------------------------------------------------------------
> Intel Research and Development Ireland Limited
> Registered in Ireland
> Registered Office: Collinstown Industrial Park, Leixlip, County Kildare
> Registered Number: 308263
>
> This e-mail and any attachments may contain confidential material for the
> sole use of the intended recipient(s). Any review or distribution by others
> is strictly prohibited. If you are not the intended recipient, please
> contact the sender and delete all copies.
>
> _______________________________________________
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Thanks Zachary,

That’s seems like the best approach; it is certainly useful from time-to-time
and makes sense that checking for out-of-range is in a shared reusable
component.

All the best,

            MartinO

From: Zachary Turner [mailto:zturner at google.com]
Sent: Wednesday, October 4, 2017 4:55 AM
To: ORiordan, Martin <martin.oriordan at intel.com>; llvm-dev <llvm-dev
at lists.llvm.org>
Subject: Re: [llvm-dev] 'cl::opt' and range checking

I don't think this is currently supported by `cl::opt`, but you can probably
write your own adapter class so that you could write
`cl::opt<cl::range<int,3,7>>`.

You'd just need to write a parser for `cl::range` and do the checking in
there.  Seems like a useful patch, I've needed this from time to time
myself.

On Tue, Oct 3, 2017 at 6:24 AM ORiordan, Martin via llvm-dev <llvm-dev at
lists.llvm.org<mailto:llvm-dev at lists.llvm.org>> wrote:
Hi LLVM-Devs,

The LLVM ‘cl::opt’ templates are really useful, and provide a lot of
flexibility.  But I don’t see any support for ranged options.  What I would like
is to have an option which is an integer type, and to restrict the set of values
provided to a simple upper and lower bound, for example between 10 and 2000.

Is there a way of expressing this with the ‘cl::opt’ templates, or do I have to
explicitly range check the values in my own code and issue a diagnostic or clamp
as appropriate?

Thanks,

            MartinO


--------------------------------------------------------------
Intel Research and Development Ireland Limited
Registered in Ireland
Registered Office: Collinstown Industrial Park, Leixlip, County Kildare
Registered Number: 308263

This e-mail and any attachments may contain confidential material for the sole
use of the intended recipient(s). Any review or distribution by others is
strictly prohibited. If you are not the intended recipient, please contact the
sender and delete all copies.
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