Re: [PATCH] x86: PIC, L-APIC and I/O APIC debug information

From: Mikael Pettersson
Date: Mon Jul 21 2008 - 10:05:19 EST


Maciej W. Rozycki writes:
> On Mon, 21 Jul 2008, Mikael Pettersson wrote:
>
> > > +#define __apicdebuginit(type) static type __init
> > ...
> > > -void __init print_IO_APIC(void)
> > > +
> > > +__apicdebuginit(void) print_IO_APIC(void)
> > > {
> >
> > I _really_ dislike how this abuses the C macro preprocessor
> > to create pointless new syntax.
> >
> > Since you're editing these function definitions anyway why
> > not just spell out "static void __init" in readable proper C?
>
> This is so that while debugging you can make all these functions global
> with a single change in one place, rather than going through the whole
> file and finding all the relevant function headers. Presumably the
> original reason for the existence of the macro. Unfortunately an
> object-like macro cannot be used here, as the "static" keyword has to come
> first in a function declaration and the section attribute has to come
> after the type designation.
>
> What's wrong with the syntax in your opinion?

It's not even remotely C-like, which will cause confusion
for anyone or anything trying to read and understand the code.

(Basically you're on the path to PL/1 or Bourne C, neither of
which were great from a software engineering point of view.)

Something like the following looks saner to me, would it work for you?

#ifdef debug
#define apicdebug /* empty */
#define __apicinit /* empty */
#else
#define apicdebug static
#define __apicinit __init
#endif
...
apicdebug void __apicinit print_IO_APIC(void)
{ .. }

/Mikael
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