Multiple return values and dynamic typing in a new frontend

Multiple return values and dynamic typing in a new frontend

[Juhani Viheräkoski]

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I recently got an idea of a new programming language and I'm thinking of
implementing it as a gcc frontend. My proposed language has multiple return
values and a possibility to use tagged dynamically typed variables, like in
Lisp. There will also be a possibility to use static typing for variables
that will only ever have a single type during their lifetime. I've read gcc
internals but haven't written any code yet. I plan to use a private
representation for parsing and semantic analysis, then convert to GIMPLE.
Is it preferred to convert multiple return values to extra reference
parameters before converting to GIMPLE or should I rather expand the
middle-end to support them properly? I'm also worried that dynamically
typed variables won't get optimized as they must be implemented as a
language-specific opaque type. But I can live with this and implement
optimization for them later. That optimization would delete unnecessary
type checks if it could prove them unnecessary.

Thank you for your insights :)

BR
Juhani Viheräkoski

Re: Multiple return values and dynamic typing in a new frontend

[Segher Boessenkool]

Hi!

On Thu, Apr 13, 2023 at 01:46:06PM +0300, Juhani Viheräkoski via Gcc-help wrote:
> Is it preferred to convert multiple return values to extra reference
> parameters before converting to GIMPLE or should I rather expand the
> middle-end to support them properly?

You can just use a struct type for the return value?  That doesn't force
the backend to put things in memory, it can still have the return value
in multiple registers (depending on ABI).


Segher

Re: Multiple return values and dynamic typing in a new frontend

[Juhani Viheräkoski]

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Thank you! This sounds like a good idea and more or less obvious, but I
didn't think about this option before.

to 13. huhtik. 2023 klo 14.36 Segher Boessenkool <segher@kernel.crashing.org>
kirjoitti:

> Hi!
>
> On Thu, Apr 13, 2023 at 01:46:06PM +0300, Juhani Viheräkoski via Gcc-help
> wrote:
> > Is it preferred to convert multiple return values to extra reference
> > parameters before converting to GIMPLE or should I rather expand the
> > middle-end to support them properly?
>
> You can just use a struct type for the return value?  That doesn't force
> the backend to put things in memory, it can still have the return value
> in multiple registers (depending on ABI).
>
>
> Segher
>