On 13-09-2018 07:36:09 -0400, Richard Yao wrote: > > > > On Sep 12, 2018, at 6:55 PM, Thomas Deutschmann <whi...@gentoo.org> wrote: > > > >> On 2018-09-12 16:50, Rich Freeman wrote: > >> There is also the case where we want these warnings to block > >> installation, because the risk of there being a problem is too great. > > > > I really disagree with that. So many devs have already said multiple > > times in this thread that "-Werror" is only turning existing warnings > > into fatal errors but "-Werror" itself doesn't add any new checks and > > more often requires "-O3" to be useful. > The way that compilers work is that the warnings are generated in the front > end while the optimization level affects the backend. That means that -O3 has > no effect on the code that does error generation. This remark about -O3 being > needed to make -Werror useful is just plain wrong.
Huh? -O3 enables more checks, which can generate more warnings. -O3
isn't "needed", but if upstream is so interested in clean and correct
code, they should've fixed all warnings in the first place and thus
enabled all of them. In fact, I expect every sane upstream to use "-O3
-Wall -Werror" in one of their automated builds. Not that this catches
anything useful on x86{,_64} when there is for instance use of signed
and unsigned char types, so it isn't conclusive.
The whole point in here is that -Werror doesn't add much if you care.
The whole point why it is not desired in Gentoo is that users don't
necessarily are developers, or even interested in fixing warnings --
regardless whether they point to real problems or not.
If there are real problems in a package (exposed by a compiler or not)
then this should ideally stand out during ~arch testing, or even before
when the Gentoo maintainer examines the build (might even use -Werror
for his own purposes). If such code ends up in stable arch we just made
a stabilisation mistake, or got royally messed up by upstream, depending
how you look at it.
Fabian
--
Fabian Groffen
Gentoo on a different level
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