Methods with more than 15 arguments?

Note that Smallapack passes all arguments into a single array.
Eliot Miranda suggested to pass first 14 arguments as usual, and only
the last+excess arguments into an array, but nobody did work on such
implementation. I do not remember pros and cons either, need to
various scan mailing lists (squeak or vm-dev ?)...

Le ven. 9 avr. 2021 à 16:01, Nicolas Cellier
<[hidden email]> a écrit :
>
> You can see a workaround at http://www.squeaksource.com/Smallapack.html
> See package
>
> Smallapack-Compiler.trunk-nice.6.mcz
>
> Le ven. 9 avr. 2021 à 13:28, Stephan Lutz <[hidden email]> a écrit :
> >
> > At the moment methods are limited to 15 arguments at most.
> >
> > Trying to compile a method with more arguments fails:
> >
> > with: arg1 with: arg2 with: arg3 with: arg4 with: arg5 with: arg6 with: arg7 with: arg8 with: arg9 with: arg10 with: arg11 with: arg12 with: arg13 with: arg14 with: arg15 with:  "Too many arguments ->"arg16
> >
> >     ^ 42
> >
> > This limitation is enforced in Encoder >> bindArg:
> >
> > bindArg: name
> >     "Declare an argument."
> >     | node |
> >     nTemps >= 15
> >         ifTrue: [^self notify: 'Too many arguments'].
> >     node := self bindTemp: name.
> >     ^ node nowHasDef nowHasRef
> >
> > Looking at where this limitation comes from, I noticed that a method header only has 4 bits reserved for the number of arguments:
> >
> > header
> >     "Answer the word containing the information about the form of the
> >      receiver and the form of the context needed to run the receiver.
> >
> >         sign:1 29-28:accessModifier 27-24:numArgs 23-18:numTemps 17:largeFrameFlag 16:hasPrimitive 15:isOptimized 14-0:numLits"
> >
> >     ^self objectAt: 1
> >
> > This, however, only uses 32 bits in total. In a 64bit image, the other 32 bits seem to be unused.
> >
> > Question: Is the limit of 15 arguments still accurate on modern VMs & bytecode sets?
> >
> > Stephan
> >
> >
> > Disclaimer: No, I do not want to pass every single pixel of my bitmap as an argument ^^. But apparently other people's C-style libraries do, and I need to interface with one through FFI. Yes, I could build and invoke ExternalFunctions manually, but I would reeeaaally prefer not to if given a choice.
> >
> >

Yep, that’s how it should work (array as 15th arg). I guess it would be relatively simple to make the encoder do that. 

Vanessa

On Fri, Apr 9, 2021 at 07:14 Nicolas Cellier <[hidden email]> wrote:

Note that Smallapack passes all arguments into a single array.
Eliot Miranda suggested to pass first 14 arguments as usual, and only
the last+excess arguments into an array, but nobody did work on such
implementation. I do not remember pros and cons either, need to
various scan mailing lists (squeak or vm-dev ?)...

Le ven. 9 avr. 2021 à 16:01, Nicolas Cellier
<[hidden email]> a écrit :
>
> You can see a workaround at http://www.squeaksource.com/Smallapack.html
> See package
>
> Smallapack-Compiler.trunk-nice.6.mcz
>
> Le ven. 9 avr. 2021 à 13:28, Stephan Lutz <[hidden email]> a écrit :
> >
> > At the moment methods are limited to 15 arguments at most.
> >
> > Trying to compile a method with more arguments fails:
> >
> > with: arg1 with: arg2 with: arg3 with: arg4 with: arg5 with: arg6 with: arg7 with: arg8 with: arg9 with: arg10 with: arg11 with: arg12 with: arg13 with: arg14 with: arg15 with:  "Too many arguments ->"arg16
> >
> >     ^ 42
> >
> > This limitation is enforced in Encoder >> bindArg:
> >
> > bindArg: name
> >     "Declare an argument."
> >     | node |
> >     nTemps >= 15
> >         ifTrue: [^self notify: 'Too many arguments'].
> >     node := self bindTemp: name.
> >     ^ node nowHasDef nowHasRef
> >
> > Looking at where this limitation comes from, I noticed that a method header only has 4 bits reserved for the number of arguments:
> >
> > header
> >     "Answer the word containing the information about the form of the
> >      receiver and the form of the context needed to run the receiver.
> >
> >         sign:1 29-28:accessModifier 27-24:numArgs 23-18:numTemps 17:largeFrameFlag 16:hasPrimitive 15:isOptimized 14-0:numLits"
> >
> >     ^self objectAt: 1
> >
> > This, however, only uses 32 bits in total. In a 64bit image, the other 32 bits seem to be unused.
> >
> > Question: Is the limit of 15 arguments still accurate on modern VMs & bytecode sets?
> >
> > Stephan
> >
> >
> > Disclaimer: No, I do not want to pass every single pixel of my bitmap as an argument ^^. But apparently other people's C-style libraries do, and I need to interface with one through FFI. Yes, I could build and invoke ExternalFunctions manually, but I would reeeaaally prefer not to if given a choice.
> >
> >

codefrau wrote

Incidentally, which library/function specifically do you want to call?

I am generating code to satisfy the OpenGL interface. The functions that are making trouble are also highly unlikely to ever be called, as they are part of outdated extensions (glLGPUCopyImageSubDataNVX, glMulticastCopyImageSubDataNV, glAsyncCopyImageSubDataNVX). That's also why I was asking and hoping for a simple solution, since it is not really worth it for me to dive deeper into this. I will probably simply ignore these methods and not generate them, and add a class comment noting their absence.