Messages in this thread |  | | | Date | Thu, 5 Oct 2006 18:37:21 +0200 | | From | Adrian Bunk <> | | Subject | Re: make-bogus-warnings-go-away tree [was: 2.6.18-mm3] |
On Thu, Oct 05, 2006 at 10:37:54AM +0200, Ingo Molnar wrote: > > * Andrew Morton <akpm@osdl.org> wrote: > > > - Added Jeff's make-bogus-warnings-go-away tree to the -mm lineup, as > > git-gccbug.patch > > Jeff: very nice! (I did this myself on a much smaller scale for the -rt > patch, because it's just so lethal if some serious warning gets lost in > the myriads of 'possible use of uninitialized' messages.) > > A small suggestion: to give GCC folks a chance to actually fix this, > could we actively annotate these places instead of working them around? > > I.e., instead of: > > long cursor = 0; > int error = 0; > - void *new_mc; > + void *new_mc = NULL; > int cpu; > cpumask_t old; > > couldnt we do: > > void *new_mc __GCC_WARN_BUG; > > and then do something like this in gcc.h: > > #ifdef CONFIG_ELIMINATE_BOGUS_GCC_WARNINGS > # define __GCC_WARN_BUG = 0 > #else > # define __GCC_WARN_BUG > #endif > > this both gives an in-source incentive for GCC folks to get rid of these > bogus warnings (or remain shamed for eternity),
Not all of the false positives are gcc bugs.
There are cases where it's technically impossible for gcc to figure out that a variable is always initialized.
> and gives us the ability > to control the presence of these workarounds (and the eventual ability > to eliminate them in the future). > > this would also mean we could merge your tree upstream without worrying > about hiding gcc bugs.
What we'd need would be some -Wno-may-be-used-uninitialized gcc option that turns off the "may be may be used uninitialized" warnings but not the "is used uninitialized" warnings.
This would: - give us a way to silence these warnings - allow people to see the warnings if they want to - not increase the maintenance overhead
> Ingo
cu Adrian
--
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