Re: [PATCH] ArmPlatformPkg: eliminate Juno gcc build warning

[Leif Lindholm <leif.lindholm@linaro.org>]

On Tue, Jun 20, 2017 at 09:52:20PM +0200, Ard Biesheuvel wrote:
> >>>> For those who have heard me mentioning this before but arguing against
> >>>> upstreaming this patch: I only just tweaked that this warning doesn't
> >>>> go away with more recent toolchains, but simply when switching to GCC5
> >>>> build profile, and hence LTO. Build failure still reproducible with
> >>>> gcc 6.3.1 and GCC49.
> >>>
> >>> /me annoyed
> >>
> >> +1
> >>
> >>> We keep hitting this with GCC, and I profoundly dislike having to add
> >>> redundant initialization sequences. Is there any other solution
> >>> possible, e.g., disable this warning for certain builds?
> >>
> >> I would really like to not disable it.
> >> When it gets it right, that's usually a pretty horrific bug caught.
> >> And if we switch to LTO as the norm, I guess these will become less
> >> noticeable over time.
> >> But it does bug me too.
> >
> > Perhaps we should introduce two macros to "MdePkg/Include/Base.h",
> >
> > #define UNUSED_POINTER NULL
> > #define UNUSED_INTEGER 0
> >
> > These could be used to suppress such warnings, without the risk of
> > misleading programmers (as to the real necessity of the variable
> > assignment at hand).
> >
> 
> Or perhaps
> 
> #ifdef __GNUC__
> #define USED(var)  var = (typeof(var))0
> #else
> #define USED(var)
> #endif

So ... I prefer this version.

However, semantically, for the situation here (may be used before
initialized), "USED" does not make sense.
Could we have an identical "INITIALIZED" instead?

/
    Leif