On Thu, Jan 13, 2022 at 06:37:27AM -0700, Simon Glass wrote: > Hi Tom, Rasmus, > > On Thu, 13 Jan 2022 at 06:07, Tom Rini <tr...@konsulko.com> wrote: > > > > On Thu, Jan 13, 2022 at 09:08:13AM +0100, Rasmus Villemoes wrote: > > > On 01/11/2021 02.17, Simon Glass wrote: > > > > Some bright sparks have decided that a cast on a constant cannot be a > > > > constant, so offsetof() produces this warning on clang-10: > > > > > > > > include/intel_gnvs.h:113:1: error: static_assert expression is not an > > > > integral constant expression > > > > check_member(acpi_global_nvs, unused2, GNVS_CHROMEOS_ACPI_OFFSET); > > > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > include/linux/kernel.h:284:2: note: expanded from macro 'check_member' > > > > offsetof(struct structure, member) == (offset), \ > > > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > include/linux/stddef.h:20:32: note: expanded from macro 'offsetof' > > > > ^ > > > > include/intel_gnvs.h:113:1: note: cast that performs the conversions of > > > > a reinterpret_cast is ot allowed in a constant expression > > > > include/linux/stddef.h:20:33: note: expanded from macro 'offsetof' > > > > > > > > Fix it by using the compiler built-in version, if available. > > > > > > > > Signed-off-by: Simon Glass <s...@chromium.org> > > > > --- > > > > > > > > include/linux/stddef.h | 8 +++++++- > > > > 1 file changed, 7 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/include/linux/stddef.h b/include/linux/stddef.h > > > > index c540f6100d4..a7f546fdfe5 100644 > > > > --- a/include/linux/stddef.h > > > > +++ b/include/linux/stddef.h > > > > @@ -1,6 +1,8 @@ > > > > #ifndef _LINUX_STDDEF_H > > > > #define _LINUX_STDDEF_H > > > > > > > > +#include <linux/compiler_types.h> > > > > + > > > > #undef NULL > > > > #if defined(__cplusplus) > > > > #define NULL 0 > > > > @@ -14,7 +16,11 @@ > > > > > > > > #ifndef __CHECKER__ > > > > #undef offsetof > > > > -#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) > > > > +#ifdef __compiler_offsetof > > > > +#define offsetof(TYPE, MEMBER) __compiler_offsetof(TYPE, MEMBER) > > > > +#else > > > > +#define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER) > > > > +#endif > > > > #endif > > > > > > > > > Can we please just drop the useless indirections? Any compiler we care > > > about provides __builtin_offsetof(), so just make the whole thing > > > > > > #undef offsetof > > > #define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE, MEMBER) > > > > > > And by "compilers we care about", that includes sparse - it has had > > > __builtin_offsetof ever since 2007. > > > > > > And we can nuke the __compiler_offsetof definition in compiler_types.h, > > > and if any users exist, just mechanically convert them to offsetof(). > > > > We should re-sync this with upstream, but that will keep the indirection > > you're objecting to here, I think. > > Yes, with this patch, this part of the file is the same as Linux (e.g. v5.16). > > So I'd like to apply it as is and deal with improvements later. > Perhaps in lockstep with Linux?
Please re-word to be clear this is a functional re-sync with v5.16, thanks! -- Tom
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