Messages in this thread | | | Date | Tue, 12 Mar 2019 20:24:47 +0300 | From | Alexey Dobriyan <> | Subject | Re: [PATCH] Drop -Wdeclaration-after-statement |
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On Mon, Mar 11, 2019 at 05:38:45PM -0700, Andrew Morton wrote: > On Sun, 10 Mar 2019 16:35:35 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote: > > > Newly added static_assert() is formally a declaration, which will give > > a warning if used in the middle of the function. > > > > ... > > > > --- a/Makefile > > +++ b/Makefile > > @@ -792,9 +792,6 @@ endif > > # arch Makefile may override CC so keep this after arch Makefile is included > > NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include) > > > > -# warn about C99 declaration after statement > > -KBUILD_CFLAGS += -Wdeclaration-after-statement > > - > > # Variable Length Arrays (VLAs) should not be used anywhere in the kernel > > KBUILD_CFLAGS += $(call cc-option,-Wvla) > > I do wish your changelogs were more elaborate :(
> So the proposal is to disable -Wdeclaration-after-statement in all > cases for all time because static_assert() doesn't work correctly?
Yes. I converted 2 cases in /proc to static_assert() and you can't write
{ [code] static_assert() }
without a warning because static_assert() is declaration. So people would move BUILD_BUG_ON() to where it doesn't belong.
> Surely there's something we can do to squish the static_assert() issue > while retaining -Wdeclaration-after-statement?
It is not good in my opinion to stick to -Wdeclaration-after-statement.
> Perhaps by making > static_assert() a nop if -Wdeclaration-after-statement is in use. > Perhaps simply by putting { } around the static_assert()?
Making a statement out of it would disable current cases where it is placed in headers.
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