Re: [avr-llvm-devel] Interrupt handling

[Weddington, E. <Eri...@at...>]

Well, we don't have to slavishly follow GCC either.

What do you think?

If you were a programmer, would you want the compiler to warn you, then
not apply the attribute and continue compilation?

Should the compiler assume that you did not want the attribute to be
applied in the case of a non-void function or one with arguments?

The compiler really doesn't know what the fix should be. I would think,
that in this case, it really is equivalent to a syntax error. These
attributes are only allowed on a non-void, non-argument function.
Otherwise, the user needs to the fix the code to expressly say what
needs to be done.

This is outside the realm of the C standard, since we're dealing with
function attributes and ISRs. Again, what do you think?

Eric Weddington

> -----Original Message-----
> From: Borja Ferrer [mailto:bor...@gm...]
> Sent: Tuesday, March 06, 2012 12:22 PM
> To: Weddington, Eric
> Cc: avr...@li...
> Subject: Re: [avr-llvm-devel] Interrupt handling
> 
> It issues a warning, so, it doesn't apply the attribute and it doesn't
abort
> compilation. I checked gcc and it warns aswell. However i can error
out if
> it's better, i leave that up to you.
> 
> 
> 2012/3/6 Weddington, Eric <Eri...@at...>
> 
> 
> 
> 
> 	> -----Original Message-----
> 	> From: Borja Ferrer [mailto:bor...@gm...]
> 
> 	> Sent: Tuesday, March 06, 2012 11:57 AM
> 	> To: Weddington, Eric
> 	> Cc: avr...@li...
> 	> Subject: Re: [avr-llvm-devel] Interrupt handling
> 	>
> 
> 	> I've added some checks to the frontend when setting the
> 	signal/interrupt
> 	> attribute that are the following:
> 	>
> 	> 1) warn when the attrib is used in things that aren't function
> 	declarations.
> 	> 2) warn when the function has arguments
> 	> 3) warn when the function doesnt return a void
> 	>
> 	> If anybody can think of any more checks that are required let
me know.
> 	>
> 	> Oh, and here are the warning messages printed for cases 2 and
3
> 	respectively,
> 	> again, if somebody has a better descriptive string or with
better
> 	english I'll
> 	> change it:
> 	>
> 	> 2) "'%0' attribute only applies to functions with no
arguments"
> 	> 3) "'%0' attribute only applies to functions with a void
return type"
> 	> where %0 is either interrupt or signal
> 	>
> 
> 
> 	Semantics question: Do you mean that it issues just a *warning*?
Or does
> 	it error out on these?
> 
>