| Message ID | 20161128064446.4892-1-pefoley2@pefoley.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Dne 28.11.2016 v 07:44 Peter Foley napsal(a): > Fix reversed conditional checking if HOSTCC is clang. > Suppress warnings about unsupported optimization options. > Suppress warnings about unused functions, as they are generated for > every module and are therefore far too spammy. > Disable clang's integrated assembler which is incompatible with kernel > asm constructs. > > Changes from v1: > * Move the $(cc-name) conditional below the definition of $(CC) > Changes from v2: > * Actually commit the changes in v2. > Changes from v3: > * HOSTCC is not guaranteed to be the same as CC, adjust accordingly. > > Signed-off-by: Peter Foley <pefoley2@pefoley.com> > --- > Makefile | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/Makefile b/Makefile > index 694111b43cf8..9c4803a74117 100644 > --- a/Makefile > +++ b/Makefile > @@ -301,12 +301,12 @@ CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \ > > HOSTCC = gcc > HOSTCXX = g++ > -HOSTCFLAGS = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -std=gnu89 > +HOSTCFLAGS = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -std=gnu89 \ > + -Wno-unused-value -Wno-unused-parameter -Wno-missing-field-initializers > HOSTCXXFLAGS = -O2 This adds new -Wno-* options also for the gcc case, is there a reason for this? Also, the -Wno-missing-field-initializers option is not available in some old gccs, so we would need a HOSTCC equivalent of cc-disable-warning. 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 Tue, Nov 29, 2016 at 6:22 AM, Michal Marek <mmarek@suse.com> wrote: > Dne 28.11.2016 v 07:44 Peter Foley napsal(a): > This adds new -Wno-* options also for the gcc case, is there a reason > for this? Also, the -Wno-missing-field-initializers option is not > available in some old gccs, so we would need a HOSTCC equivalent of > cc-disable-warning. > > Michal It appeared that the conditional was simply reversed, as -fno-delete-null-pointer-checks is only supported by gcc, and explicitly not supported by clang. (see https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/Makefile?id=61163efae02040f66a95c8ed17f4407951ba58fa) It could be that the fno-delete-null-pointer-checks option was simply misplaced, and the Wno-options should still be guarded by if(clang), would that be a better approach? Thanks, Peter -- 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 2016-12-01 19:13, Peter Foley wrote: > On Tue, Nov 29, 2016 at 6:22 AM, Michal Marek <mmarek@suse.com> wrote: >> Dne 28.11.2016 v 07:44 Peter Foley napsal(a): >> This adds new -Wno-* options also for the gcc case, is there a reason >> for this? Also, the -Wno-missing-field-initializers option is not >> available in some old gccs, so we would need a HOSTCC equivalent of >> cc-disable-warning. >> >> Michal > > It appeared that the conditional was simply reversed, as > -fno-delete-null-pointer-checks is only supported by gcc, and > explicitly not supported by clang. > (see https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/Makefile?id=61163efae02040f66a95c8ed17f4407951ba58fa) > It could be that the fno-delete-null-pointer-checks option was simply > misplaced, and the Wno-options should still be guarded by if(clang), > would that be a better approach? I think so. The -Wno-* options had not been present before clang support was added. It really looks like the -fno-delete-null-pointer-checks should not be there. Added Behan to CC. 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 694111b43cf8..9c4803a74117 100644 --- a/Makefile +++ b/Makefile @@ -301,12 +301,12 @@ CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \ HOSTCC = gcc HOSTCXX = g++ -HOSTCFLAGS = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -std=gnu89 +HOSTCFLAGS = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -std=gnu89 \ + -Wno-unused-value -Wno-unused-parameter -Wno-missing-field-initializers HOSTCXXFLAGS = -O2 -ifeq ($(shell $(HOSTCC) -v 2>&1 | grep -c "clang version"), 1) -HOSTCFLAGS += -Wno-unused-value -Wno-unused-parameter \ - -Wno-missing-field-initializers -fno-delete-null-pointer-checks +ifneq ($(shell $(HOSTCC) -v 2>&1 | grep -c "clang version"), 1) +HOSTCFLAGS += -fno-delete-null-pointer-checks endif # Decide whether to build built-in, modular, or both. @@ -685,7 +685,9 @@ KBUILD_CFLAGS += $(stackp-flag) ifeq ($(cc-name),clang) KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,) KBUILD_CPPFLAGS += $(call cc-option,-Wno-unknown-warning-option,) +KBUILD_CFLAGS += $(call cc-disable-warning, ignored-optimization-argument) KBUILD_CFLAGS += $(call cc-disable-warning, unused-variable) +KBUILD_CFLAGS += $(call cc-disable-warning, unused-function) KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier) KBUILD_CFLAGS += $(call cc-disable-warning, gnu) # Quiet clang warning: comparison of unsigned expression < 0 is always false @@ -695,6 +697,8 @@ KBUILD_CFLAGS += $(call cc-disable-warning, tautological-compare) # See modpost pattern 2 KBUILD_CFLAGS += $(call cc-option, -mno-global-merge,) KBUILD_CFLAGS += $(call cc-option, -fcatch-undefined-behavior) +KBUILD_CFLAGS += $(call cc-option, -fno-integrated-as) +KBUILD_AFLAGS += $(call cc-option, -fno-integrated-as) else # These warnings generated too much noise in a regular build.
Fix reversed conditional checking if HOSTCC is clang. Suppress warnings about unsupported optimization options. Suppress warnings about unused functions, as they are generated for every module and are therefore far too spammy. Disable clang's integrated assembler which is incompatible with kernel asm constructs. Changes from v1: * Move the $(cc-name) conditional below the definition of $(CC) Changes from v2: * Actually commit the changes in v2. Changes from v3: * HOSTCC is not guaranteed to be the same as CC, adjust accordingly. Signed-off-by: Peter Foley <pefoley2@pefoley.com> --- Makefile | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)