llvm dev - Aug 2016 - llvm::cl::opt and enums

I was adding a new option for our backend, and because of the nature of the
option I wanted to use an 'enum', something like:

 

enum Direction {

  left,

  right,

  up,

  down

};

 

cl:opt<Direction> myOpt("option-switch", cl::init(up),
cl::desc("what it
does"), cl::Hidden);

 

This bit is fine, but then I wanted to change it on the command-line to
'clang' and tried:

 

clang ... -mllvm -option-switch=3 ...

but that doesn't work, and I get something like "invalid option
'3'".  If I
change the type to 'int' it works fine.  Is it valid to use an
'enum' in
this way?  And if so, what is the correct way of specifying a value to the
option if I do use an 'enum' for the type?

 

Thanks,

 

            MartinO

 

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On 31 August 2016 at 19:06, Martin J. O'Riordan via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
> but that doesn’t work, and I get something like “invalid option ‘3’”.  If I
> change the type to ‘int’ it works fine.  Is it valid to use an ‘enum’ in
> this way?  And if so, what is the correct way of specifying a value to the
> option if I do use an ‘enum’ for the type?
Try something similar to this:

https://reviews.llvm.org/D24070

cheers,
--renato

Thanks Renato,

Yes, checking it early as a string would work.  Originally I had thought of
making the option be a string, but since I need to check it for about 50% of our
MachineInstr's, using StringSwitch didn't make sense for performance. 
But pre-handling the option like this should work.

All the best,

	MartinO

-----Original Message-----
From: Renato Golin [mailto:renato.golin at linaro.org] 
Sent: 31 August 2016 19:13
To: Martin J. O'Riordan <Martin.ORiordan at movidius.com>
Cc: LLVM Developers <llvm-dev at lists.llvm.org>
Subject: Re: [llvm-dev] llvm::cl::opt and enums

On 31 August 2016 at 19:06, Martin J. O'Riordan via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> but that doesn’t work, and I get something like “invalid option ‘3’”.  
> If I change the type to ‘int’ it works fine.  Is it valid to use an 
> ‘enum’ in this way?  And if so, what is the correct way of specifying 
> a value to the option if I do use an ‘enum’ for the type?
Try something similar to this:

https://reviews.llvm.org/D24070

cheers,
--renato

I have to follow up to this, and say thanks very much to you Renato.

 

Your recommended solution not only works perfectly, it is also very elegant and
I can use meaningful words for the options instead of having to remember the
enumerate values.  It is also far safer, because it rejects invalid values.

 

Thanks again,

 

            MartinO

 

-----Original Message-----
From: Renato Golin [mailto:renato.golin at linaro.org] 
Sent: 31 August 2016 19:13
To: Martin J. O'Riordan <Martin.ORiordan at movidius.com>
Cc: LLVM Developers <llvm-dev at lists.llvm.org>
Subject: Re: [llvm-dev] llvm::cl::opt and enums

 

On 31 August 2016 at 19:06, Martin J. O'Riordan via llvm-dev <
<mailto:llvm-dev at lists.llvm.org> llvm-dev at lists.llvm.org> wrote:
> but that doesn’t work, and I get something like “invalid option ‘3’”.  
> If I change the type to ‘int’ it works fine.  Is it valid to use an 
> ‘enum’ in this way?  And if so, what is the correct way of specifying 
> a value to the option if I do use an ‘enum’ for the type?
 

Try something similar to this:

 

 <https://reviews.llvm.org/D24070> https://reviews.llvm.org/D24070

 

cheers,

--renato

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