i915 enables a wider set of warnings with '-Wall -Wextra' then disables
several with cc-disable-warning. If an unknown flag gets added to
KBUILD_CFLAGS when building with clang, all subsequent calls to
cc-{disable-warning,option} will fail, meaning that all of these
warnings do not get disabled [1].
A separate series will address the root cause of the issue by not adding
these flags when building with clang [2]; however, the symptom of these
extra warnings appearing can be addressed separately by just removing
the calls to cc-disable-warning, which makes the build ever so slightly
faster because the compiler does not need to be called as much before
building.
The following warnings are supported by GCC 4.9 and clang 10.0.1, which
are the minimum supported versions of these compilers so the call to
cc-disable-warning is not necessary. Masahiro cleaned this up for the
reset of the kernel in commit 4c8dd95a723d ("kbuild: add some extra
warning flags unconditionally").
* -Wmissing-field-initializers
* -Wsign-compare
* -Wtype-limits
* -Wunused-parameter
-Wunused-but-set-variable was implemented in clang 13.0.0 and
-Wframe-address was implemented in clang 12.0.0 so the
cc-disable-warning calls are kept for these two warnings.
Lastly, -Winitializer-overrides is clang's version of -Woverride-init,
which is disabled for the specific files that are problematic. clang
added a compatibility alias in clang 8.0.0 so -Winitializer-overrides
can be removed.
[1]: https://lore.kernel.org/r/[email protected]/
[2]: https://lore.kernel.org/r/[email protected]/
Signed-off-by: Nathan Chancellor <[email protected]>
---
NOTE: This is based on my series to enable -Wsometimes-initialized here:
https://lore.kernel.org/r/[email protected]/
I sent it separately as this can go into whatever release but I would
like for that series to go into 5.15.
drivers/gpu/drm/i915/Makefile | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 335ba9f43d8f..6b38547543b1 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -13,13 +13,11 @@
# will most likely get a sudden build breakage... Hopefully we will fix
# new warnings before CI updates!
subdir-ccflags-y := -Wall -Wextra
-subdir-ccflags-y += $(call cc-disable-warning, unused-parameter)
-subdir-ccflags-y += $(call cc-disable-warning, type-limits)
-subdir-ccflags-y += $(call cc-disable-warning, missing-field-initializers)
+subdir-ccflags-y += -Wno-unused-parameter
+subdir-ccflags-y += -Wno-type-limits
+subdir-ccflags-y += -Wno-missing-field-initializers
+subdir-ccflags-y += -Wno-sign-compare
subdir-ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
-# clang warnings
-subdir-ccflags-y += $(call cc-disable-warning, sign-compare)
-subdir-ccflags-y += $(call cc-disable-warning, initializer-overrides)
subdir-ccflags-y += $(call cc-disable-warning, frame-address)
subdir-ccflags-$(CONFIG_DRM_I915_WERROR) += -Werror
base-commit: fb43ebc83e069625cfeeb2490efc3ffa0013bfa4
prerequisite-patch-id: 31c28450ed7e8785dce967a16db6d52eff3d7d6d
prerequisite-patch-id: 372dfa0e07249f207acc1942ab0e39b13ff229b2
prerequisite-patch-id: 1a585fa6cda50c32ad1e3ac8235d3cff1b599978
--
2.33.0
On Tue, Aug 24, 2021 at 4:23 PM Nathan Chancellor <[email protected]> wrote:
>
> i915 enables a wider set of warnings with '-Wall -Wextra' then disables
> several with cc-disable-warning. If an unknown flag gets added to
> KBUILD_CFLAGS when building with clang, all subsequent calls to
> cc-{disable-warning,option} will fail, meaning that all of these
> warnings do not get disabled [1].
>
> A separate series will address the root cause of the issue by not adding
> these flags when building with clang [2]; however, the symptom of these
> extra warnings appearing can be addressed separately by just removing
> the calls to cc-disable-warning, which makes the build ever so slightly
> faster because the compiler does not need to be called as much before
> building.
>
> The following warnings are supported by GCC 4.9 and clang 10.0.1, which
> are the minimum supported versions of these compilers so the call to
> cc-disable-warning is not necessary. Masahiro cleaned this up for the
> reset of the kernel in commit 4c8dd95a723d ("kbuild: add some extra
> warning flags unconditionally").
>
> * -Wmissing-field-initializers
> * -Wsign-compare
> * -Wtype-limits
> * -Wunused-parameter
>
> -Wunused-but-set-variable was implemented in clang 13.0.0 and
> -Wframe-address was implemented in clang 12.0.0 so the
> cc-disable-warning calls are kept for these two warnings.
>
> Lastly, -Winitializer-overrides is clang's version of -Woverride-init,
> which is disabled for the specific files that are problematic. clang
> added a compatibility alias in clang 8.0.0 so -Winitializer-overrides
> can be removed.
>
> [1]: https://lore.kernel.org/r/[email protected]/
> [2]: https://lore.kernel.org/r/[email protected]/
>
> Signed-off-by: Nathan Chancellor <[email protected]>
Thanks for the patch! Do you need to re-ping, rebase, or resend that
other series?
Reviewed-by: Nick Desaulniers <[email protected]>
> ---
>
> NOTE: This is based on my series to enable -Wsometimes-initialized here:
>
> https://lore.kernel.org/r/[email protected]/
>
> I sent it separately as this can go into whatever release but I would
> like for that series to go into 5.15.
>
> drivers/gpu/drm/i915/Makefile | 10 ++++------
> 1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 335ba9f43d8f..6b38547543b1 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -13,13 +13,11 @@
> # will most likely get a sudden build breakage... Hopefully we will fix
> # new warnings before CI updates!
> subdir-ccflags-y := -Wall -Wextra
> -subdir-ccflags-y += $(call cc-disable-warning, unused-parameter)
> -subdir-ccflags-y += $(call cc-disable-warning, type-limits)
> -subdir-ccflags-y += $(call cc-disable-warning, missing-field-initializers)
> +subdir-ccflags-y += -Wno-unused-parameter
> +subdir-ccflags-y += -Wno-type-limits
> +subdir-ccflags-y += -Wno-missing-field-initializers
> +subdir-ccflags-y += -Wno-sign-compare
> subdir-ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
> -# clang warnings
> -subdir-ccflags-y += $(call cc-disable-warning, sign-compare)
> -subdir-ccflags-y += $(call cc-disable-warning, initializer-overrides)
> subdir-ccflags-y += $(call cc-disable-warning, frame-address)
> subdir-ccflags-$(CONFIG_DRM_I915_WERROR) += -Werror
>
>
> base-commit: fb43ebc83e069625cfeeb2490efc3ffa0013bfa4
> prerequisite-patch-id: 31c28450ed7e8785dce967a16db6d52eff3d7d6d
> prerequisite-patch-id: 372dfa0e07249f207acc1942ab0e39b13ff229b2
> prerequisite-patch-id: 1a585fa6cda50c32ad1e3ac8235d3cff1b599978
> --
> 2.33.0
>
--
Thanks,
~Nick Desaulniers
On 8/25/2021 4:03 PM, Nick Desaulniers wrote:
> On Tue, Aug 24, 2021 at 4:23 PM Nathan Chancellor <[email protected]> wrote:
>>
>> i915 enables a wider set of warnings with '-Wall -Wextra' then disables
>> several with cc-disable-warning. If an unknown flag gets added to
>> KBUILD_CFLAGS when building with clang, all subsequent calls to
>> cc-{disable-warning,option} will fail, meaning that all of these
>> warnings do not get disabled [1].
>>
>> A separate series will address the root cause of the issue by not adding
>> these flags when building with clang [2]; however, the symptom of these
>> extra warnings appearing can be addressed separately by just removing
>> the calls to cc-disable-warning, which makes the build ever so slightly
>> faster because the compiler does not need to be called as much before
>> building.
>>
>> The following warnings are supported by GCC 4.9 and clang 10.0.1, which
>> are the minimum supported versions of these compilers so the call to
>> cc-disable-warning is not necessary. Masahiro cleaned this up for the
>> reset of the kernel in commit 4c8dd95a723d ("kbuild: add some extra
>> warning flags unconditionally").
>>
>> * -Wmissing-field-initializers
>> * -Wsign-compare
>> * -Wtype-limits
>> * -Wunused-parameter
>>
>> -Wunused-but-set-variable was implemented in clang 13.0.0 and
>> -Wframe-address was implemented in clang 12.0.0 so the
>> cc-disable-warning calls are kept for these two warnings.
>>
>> Lastly, -Winitializer-overrides is clang's version of -Woverride-init,
>> which is disabled for the specific files that are problematic. clang
>> added a compatibility alias in clang 8.0.0 so -Winitializer-overrides
>> can be removed.
>>
>> [1]: https://lore.kernel.org/r/[email protected]/
>> [2]: https://lore.kernel.org/r/[email protected]/
>>
>> Signed-off-by: Nathan Chancellor <[email protected]>
>
> Thanks for the patch! Do you need to re-ping, rebase, or resend that
> other series?
> Reviewed-by: Nick Desaulniers <[email protected]>
I assume you mean the series below rather than above? I sent this patch
right after that series and it has one set of reviews so I am hoping the
i915 maintainers will pick them up soon so this one can be applied
afterwards or resent.
Thank you for the review!
Cheers,
Nathan
>> ---
>>
>> NOTE: This is based on my series to enable -Wsometimes-initialized here:
>>
>> https://lore.kernel.org/r/[email protected]/
>>
>> I sent it separately as this can go into whatever release but I would
>> like for that series to go into 5.15.
>>
>> drivers/gpu/drm/i915/Makefile | 10 ++++------
>> 1 file changed, 4 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
>> index 335ba9f43d8f..6b38547543b1 100644
>> --- a/drivers/gpu/drm/i915/Makefile
>> +++ b/drivers/gpu/drm/i915/Makefile
>> @@ -13,13 +13,11 @@
>> # will most likely get a sudden build breakage... Hopefully we will fix
>> # new warnings before CI updates!
>> subdir-ccflags-y := -Wall -Wextra
>> -subdir-ccflags-y += $(call cc-disable-warning, unused-parameter)
>> -subdir-ccflags-y += $(call cc-disable-warning, type-limits)
>> -subdir-ccflags-y += $(call cc-disable-warning, missing-field-initializers)
>> +subdir-ccflags-y += -Wno-unused-parameter
>> +subdir-ccflags-y += -Wno-type-limits
>> +subdir-ccflags-y += -Wno-missing-field-initializers
>> +subdir-ccflags-y += -Wno-sign-compare
>> subdir-ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
>> -# clang warnings
>> -subdir-ccflags-y += $(call cc-disable-warning, sign-compare)
>> -subdir-ccflags-y += $(call cc-disable-warning, initializer-overrides)
>> subdir-ccflags-y += $(call cc-disable-warning, frame-address)
>> subdir-ccflags-$(CONFIG_DRM_I915_WERROR) += -Werror
>>
>>
>> base-commit: fb43ebc83e069625cfeeb2490efc3ffa0013bfa4
>> prerequisite-patch-id: 31c28450ed7e8785dce967a16db6d52eff3d7d6d
>> prerequisite-patch-id: 372dfa0e07249f207acc1942ab0e39b13ff229b2
>> prerequisite-patch-id: 1a585fa6cda50c32ad1e3ac8235d3cff1b599978
>> --
>> 2.33.0
>>
>
>