Messages in this thread | | | From | Miguel Ojeda <> | Date | Wed, 25 Nov 2020 00:46:23 +0100 | Subject | Re: [PATCH 000/141] Fix fall-through warnings for Clang |
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On Tue, Nov 24, 2020 at 1:58 AM Finn Thain <fthain@telegraphics.com.au> wrote: > > What I meant was that you've used pessimism as if it was fact.
"future mistakes that it might prevent" is neither pessimism nor states a fact.
> For example, "There is no way to guess what the effect would be if the > compiler trained programmers to add a knee-jerk 'break' statement to avoid > a warning".
It is only knee-jerk if you think you are infallible.
> Moreover, what I meant was that preventing programmer mistakes is a > problem to be solved by development tools
This warning comes from a development tool -- the compiler.
> The idea that retro-fitting new > language constructs onto mature code is somehow necessary to "prevent > future mistakes" is entirely questionable.
The kernel is not a frozen codebase.
Further, "mature code vs. risk of change" arguments don't apply here because the semantics of the program and binary output isn't changing.
> Sure. And if you put -Wimplicit-fallthrough into the Makefile and if that > leads to well-intentioned patches that cause regressions, it is partly on > you.
Again: adding a `fallthrough` does not change the program semantics. If you are a maintainer and want to cross-check, compare the codegen.
> Have you ever considered the overall cost of the countless > -Wpresume-incompetence flags?
Yeah: negative. On the other hand, the overall cost of the countless -fI-am-infallible flags is very noticeable.
> Perhaps you pay the power bill for a build farm that produces logs that > no-one reads? Perhaps you've run git bisect, knowing that the compiler > messages are not interesting? Or compiled software in using a language > that generates impenetrable messages? If so, here's a tip: > > # grep CFLAGS /etc/portage/make.conf > CFLAGS="... -Wno-all -Wno-extra ..." > CXXFLAGS="${CFLAGS}" > > Now allow me some pessimism: the hardware upgrades, gigawatt hours and > wait time attributable to obligatory static analyses are a net loss.
If you really believe compiler warnings and static analysis are useless and costly, I think there is not much point in continuing the discussion.
> No, it's not for me to prove that such patches don't affect code > generation. That's for the patch author and (unfortunately) for reviewers.
I was not asking you to prove it. I am stating that proving it is very easy.
Cheers, Miguel
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