Re: [PATCH v2 2/2] x86: Support compiling out human-friendly processor feature names

From: Josh Triplett
Date: Sun Feb 23 2014 - 16:56:46 EST


On Sun, Feb 23, 2014 at 01:44:20PM -0800, H. Peter Anvin wrote:
> On 02/23/2014 01:32 PM, Josh Triplett wrote:
> >
> > Because, in order to un-break the build, v3 wraps an ifdef around that
> > dependency, to prevent building cpustr.h. Otherwise, the rule for
> > cpustr.h tries and fails to build mkcpustr.
> >
>
> Why did it fail to build mkcpustr? It would seem that mkcpustr is or at
> least ought to be completely agnostic to any of these options.
>
> The extra build machinery here seems completely pointless.
>
> I agree that the #ifdef isn't a big deal, but all this extra machinery
> really indicates something is odd.
>
> Oh, and of course, looking at the v2 patchset, the problem is the ifdef
> around the mkcapflags shell script which really shouldn't be necessary.
> We may have to add a rule to force capflags.c to be built even if
> capflags.o is not requested, but that is fine.
>
> That will cut down on the Makefile hacks considerably, and will avoid
> this problem completely.

Why have the build system waste time building several things that won't
be used? It seems like the Makefiles are exactly where we *should* have
the ifdef machinery, rather than in source. I'd happily add another
ifdef in the Makefile rule that builds cpustr.h, to generate a stub
cpustr.h header, and then remove one more ifdef in the source.

- Josh Triplett
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