| Message ID | 20200311194121.38047-1-natechancellor@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] kbuild: Disable -Wpointer-to-enum-cast | expand |
On Thu, Mar 12, 2020 at 4:41 AM Nathan Chancellor <natechancellor@gmail.com> wrote: > > Clang's -Wpointer-to-int-cast deviates from GCC in that it warns when > casting to enums. The kernel does this in certain places, such as device > tree matches to set the version of the device being used, which allows > the kernel to avoid using a gigantic union. > > https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L428 > https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L402 > https://elixir.bootlin.com/linux/v5.5.8/source/include/linux/mod_devicetable.h#L264 > > To avoid a ton of false positive warnings, disable this particular part > of the warning, which has been split off into a separate diagnostic so > that the entire warning does not need to be turned off for clang. It > will be visible under W=1 in case people want to go about fixing these > easily and enabling the warning treewide. > > Cc: stable@vger.kernel.org > Link: https://github.com/ClangBuiltLinux/linux/issues/887 > Link: https://github.com/llvm/llvm-project/commit/2a41b31fcdfcb67ab7038fc2ffb606fd50b83a84 > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> > --- Applied to linux-kbuild. Thanks. > > v1 -> v2: > > * Move under scripts/Makefile.extrawarn, as requested by Masahiro > > scripts/Makefile.extrawarn | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn > index ecddf83ac142..ca08f2fe7c34 100644 > --- a/scripts/Makefile.extrawarn > +++ b/scripts/Makefile.extrawarn > @@ -48,6 +48,7 @@ KBUILD_CFLAGS += -Wno-initializer-overrides > KBUILD_CFLAGS += -Wno-format > KBUILD_CFLAGS += -Wno-sign-compare > KBUILD_CFLAGS += -Wno-format-zero-length > +KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast) > endif > > endif > -- > 2.26.0.rc1 > > -- > You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. > To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20200311194121.38047-1-natechancellor%40gmail.com.
diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index ecddf83ac142..ca08f2fe7c34 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -48,6 +48,7 @@ KBUILD_CFLAGS += -Wno-initializer-overrides KBUILD_CFLAGS += -Wno-format KBUILD_CFLAGS += -Wno-sign-compare KBUILD_CFLAGS += -Wno-format-zero-length +KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast) endif endif
Clang's -Wpointer-to-int-cast deviates from GCC in that it warns when casting to enums. The kernel does this in certain places, such as device tree matches to set the version of the device being used, which allows the kernel to avoid using a gigantic union. https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L428 https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L402 https://elixir.bootlin.com/linux/v5.5.8/source/include/linux/mod_devicetable.h#L264 To avoid a ton of false positive warnings, disable this particular part of the warning, which has been split off into a separate diagnostic so that the entire warning does not need to be turned off for clang. It will be visible under W=1 in case people want to go about fixing these easily and enabling the warning treewide. Cc: stable@vger.kernel.org Link: https://github.com/ClangBuiltLinux/linux/issues/887 Link: https://github.com/llvm/llvm-project/commit/2a41b31fcdfcb67ab7038fc2ffb606fd50b83a84 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> --- v1 -> v2: * Move under scripts/Makefile.extrawarn, as requested by Masahiro scripts/Makefile.extrawarn | 1 + 1 file changed, 1 insertion(+)