| Message ID | 3799453.oCg1CdOrtm@wuerfel (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 2015-11-23 17:26, Arnd Bergmann wrote: > These are all false positives that either rob someone's time when trying > to figure out whether they are real, or they get people to send wrong > patches to shut up the warnings. [...] > diff --git a/Makefile b/Makefile > index 5e01a416c6e4..f8b921658f29 100644 > --- a/Makefile > +++ b/Makefile > @@ -626,7 +626,11 @@ KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) > ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE > KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,) > else > -KBUILD_CFLAGS += -O2 > +ifdef CONFIG_PROFILE_ALL_BRANCHES > +KBUILD_CFLAGS += -O2 $(call cc-disable-warning,maybe-uninitialized,) > +else > +KBUILD_CFLAGS += -O2 > +endif Does it only happen with -O2? Normally, we would add it outside the ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE. Michal -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tuesday 24 November 2015 11:20:43 Michal Marek wrote: > > diff --git a/Makefile b/Makefile > > index 5e01a416c6e4..f8b921658f29 100644 > > --- a/Makefile > > +++ b/Makefile > > @@ -626,7 +626,11 @@ KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) > > ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE > > KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,) > > else > > -KBUILD_CFLAGS += -O2 > > +ifdef CONFIG_PROFILE_ALL_BRANCHES > > +KBUILD_CFLAGS += -O2 $(call cc-disable-warning,maybe-uninitialized,) > > +else > > +KBUILD_CFLAGS += -O2 > > +endif > > Does it only happen with -O2? Normally, we would add it outside the > ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE. > We already disable the warning for -Os builds based on a patch we merged a while ago. It seems easier to add it to the block we already have. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2015-11-24 11:42, Arnd Bergmann wrote: > On Tuesday 24 November 2015 11:20:43 Michal Marek wrote: >>> diff --git a/Makefile b/Makefile >>> index 5e01a416c6e4..f8b921658f29 100644 >>> --- a/Makefile >>> +++ b/Makefile >>> @@ -626,7 +626,11 @@ KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) >>> ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE >>> KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,) >>> else >>> -KBUILD_CFLAGS += -O2 >>> +ifdef CONFIG_PROFILE_ALL_BRANCHES >>> +KBUILD_CFLAGS += -O2 $(call cc-disable-warning,maybe-uninitialized,) >>> +else >>> +KBUILD_CFLAGS += -O2 >>> +endif >> >> Does it only happen with -O2? Normally, we would add it outside the >> ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE. >> > > We already disable the warning for -Os builds based on a patch we merged > a while ago. It seems easier to add it to the block we already have. I'm blind, sorry. Michal -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Makefile b/Makefile index 5e01a416c6e4..f8b921658f29 100644 --- a/Makefile +++ b/Makefile @@ -626,7 +626,11 @@ KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,) else -KBUILD_CFLAGS += -O2 +ifdef CONFIG_PROFILE_ALL_BRANCHES +KBUILD_CFLAGS += -O2 $(call cc-disable-warning,maybe-uninitialized,) +else +KBUILD_CFLAGS += -O2 +endif endif # Tell gcc to never replace conditional load with a non-conditional one
CONFIG_PROFILE_ALL_BRANCHES confuses gcc-5.x to the degree that it prints incorrect warnings about a lot of variables that it thinks can be used uninitialized, e.g.: i2c/busses/i2c-diolan-u2c.c: In function 'diolan_usb_xfer': i2c/busses/i2c-diolan-u2c.c:391:16: warning: 'byte' may be used uninitialized in this function iio/gyro/itg3200_core.c: In function 'itg3200_probe': iio/gyro/itg3200_core.c:213:6: warning: 'val' may be used uninitialized in this function leds/leds-lp55xx-common.c: In function 'lp55xx_update_bits': leds/leds-lp55xx-common.c:350:6: warning: 'tmp' may be used uninitialized in this function misc/bmp085.c: In function 'show_pressure': misc/bmp085.c:363:10: warning: 'pressure' may be used uninitialized in this function power/ds2782_battery.c: In function 'ds2786_get_capacity': power/ds2782_battery.c:214:17: warning: 'raw' may be used uninitialized in this function These are all false positives that either rob someone's time when trying to figure out whether they are real, or they get people to send wrong patches to shut up the warnings. Nobody normally wants to run a CONFIG_PROFILE_ALL_BRANCHES kernel in production, so disabling the whole class of warnings for this configuration has no serious downsides either. Signed-off-by: Arnd Bergmann <arnd@arndb.de> -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html