if (CONFIG_FOO) Re: 2.4.0-test8-pre1 is quite bad / how about integrating Rik's VM

From: Martin MaD Douda (martin@douda.net)
Date: Wed Sep 06 2000 - 05:22:03 EST


On Tue, 5 Sep 2000, Alexander Viro wrote:

>
> The _real_ problem is preprocessor abuse. BTW, could we schedule for
> 2.5 the following?
> * things like CONFIG_FOO are _always_ defined. As 0 or 1, that is.
> * #ifdef CONFIG_FOO => if (CONFIG_FOO) in *.c. gcc will kill the unused
> branches just fine.
> * Yes, Virginia, it means that controlflow-affecting expansion has to
> go. Good riddance, IMO.
>
> Goal: making sure that every bloody line of the files we choose to
> compile goes through the parser. Will do wonders with test coverage and will
> make analysis tools like tags viable. Then we can just use the gcc frontend
> output as input for such beasts.
>

Problem: every bloody line will go through the parser. There is too many
lines. Compilation is realy slow today. I'm affraid this approach would
make it worse. Note that 2.4.0-test7 has more than 2.75 milion lines.
Or did you mean drivers will be (optionally?) excluded from this
compile-it-all-and-then-optimize-it-away?

I can understand advantages the if(CONFIG_FOO) approach has, but I'm not
sure it is worth compilation slowdown.

                                                Martin

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[1]+ Done rm -rf /

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