On 20 June 2017 at 17:44, Laszlo Ersek <[email protected]> wrote: > On 06/20/17 14:00, Leif Lindholm wrote: >> On Tue, Jun 20, 2017 at 01:28:38PM +0200, Ard Biesheuvel wrote: >>> (+ Laszlo) >>> >>> On 20 June 2017 at 13:00, Leif Lindholm <[email protected]> wrote: >>>> When building without LTO, gcc incorrectly resolves the hazards for >>>> 'PciRegBase’ when inlining, leading to "may be used uninitialized" >>>> warnings (and hence build failure with -Werror). >>>> Eliminate this warning by explicitly initializing the variable to 0. >>>> >>>> Contributed-under: TianoCore Contribution Agreement 1.0 >>>> Signed-off-by: Leif Lindholm <[email protected]> >>> >>> Reviewed-by: Ard Biesheuvel <[email protected]> >> >> Thanks! >> >>>> --- >>>> >>>> For those who have heard me mentioning this before but arguing against >>>> upstreaming this patch: I only just tweaked that this warning doesn't >>>> go away with more recent toolchains, but simply when switching to GCC5 >>>> build profile, and hence LTO. Build failure still reproducible with >>>> gcc 6.3.1 and GCC49. >>> >>> /me annoyed >> >> +1 >> >>> We keep hitting this with GCC, and I profoundly dislike having to add >>> redundant initialization sequences. Is there any other solution >>> possible, e.g., disable this warning for certain builds? >> >> I would really like to not disable it. >> When it gets it right, that's usually a pretty horrific bug caught. >> And if we switch to LTO as the norm, I guess these will become less >> noticeable over time. >> But it does bug me too. > > Perhaps we should introduce two macros to "MdePkg/Include/Base.h", > > #define UNUSED_POINTER NULL > #define UNUSED_INTEGER 0 > > These could be used to suppress such warnings, without the risk of > misleading programmers (as to the real necessity of the variable > assignment at hand). >
Or perhaps #ifdef __GNUC__ #define USED(var) var = (typeof(var))0 #else #define USED(var) #endif _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
