Re: [PATCH] kbuild, LLVMLinux: Add -Werror to cc-option to support clang

From: Behan Webster
Date: Thu Sep 25 2014 - 20:48:40 EST

On 09/25/14 06:34, Michal Marek wrote:
On 2014-09-24 20:50, Behan Webster wrote:
Getting clang to error on unused flags wasn't trivial (this change broke
a lot of builds apparently). Fortunately we weren't the only ones who
wanted it to behave like gcc in this case. I think it's going to be
*much* harder to do the same for warnings. The argument given by
supporters of the current situation is that if a warning isn't
supported, why break the build? *sigh*
I guess the reason to accept unknown warnings opentions is compatibility
with Makefiles with hardcoded gcc-isms. BTW, GCC at some point started
to ignore unknown -Wno-* options, for everyone's good of course. That's
why we ended up with the cc-disable-warning function. If -W* options for
clang need special care, then it might be a good idea to introduce
cc-warning with the conditional -Werror for clang. There are not that
many places where we add warnings, so the patch would be still short.
That way, the possible silent failure is limited only to warning options
with clang, which is not such a big deal.
I'll try this approach.



Behan Webster

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