Messages in this thread |  | | Subject | Re: [PATCH] compiler-gcc: get back Clang build | From | Joe Perches <> | Date | Tue, 21 Aug 2018 10:20:29 -0700 |
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On Wed, 2018-08-22 at 02:13 +0900, Masahiro Yamada wrote: > Hi Joe, > > > 2018-08-21 19:39 GMT+09:00 Joe Perches <joe@perches.com>: > > On Tue, 2018-08-21 at 15:48 +0900, Masahiro Yamada wrote: > > > Commit cafa0010cd51 ("Raise the minimum required gcc version to 4.6") > > > missed the fact that <linux/compiler-gcc.h> is included by Clang > > > as well as by GCC. > > > > > > Clang actually defines __GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__ > > > and it looks like GCC 4.2.1. > > > > > > $ scripts/gcc-version.sh -p clang > > > 040201 > > > > Perhaps this would work, but I can't test it as > > my clang version doesn't otherwise build a defconfig > > and errors out with > > > > $ make CC=clang > > arch/x86/Makefile:179: *** Compiler lacks asm-goto support.. Stop. > > > > --- > > include/linux/compiler-gcc.h | 17 +++++++++++++++++ > > 1 file changed, 17 insertions(+) > > > > diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h > > index 3e70b7d4e9ed..3a06ad823fa4 100644 > > --- a/include/linux/compiler-gcc.h > > +++ b/include/linux/compiler-gcc.h > > @@ -3,6 +3,23 @@ > > #error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead." > > #endif > > > > +/* > > + * Override clang compiler version #defines > > + * > > + * compiler_types.h always #includes compiler-gcc.h before compiler-clang,h > > + * but clang sets these __GNUC version #defines to 4.2.1. > > + * This breaks the gcc minimum version of 4.6.0, so override the clang > > + * definitions to 4.6.0 > > + */ > > +#ifdef __clang__ > > + #undef __GNUC__ > > + #undef __GNUC_MINOR__ > > + #undef __GNUC_PATCHLEVEL__ > > + #define __GNUC__ 4 > > + #define __GNUC_MINOR__ 6 > > + #define __GNUC_PATCHLEVEL__ 0 > > +#endif > > + > > > > This patch does not work. > > It only addresses the > "# error Sorry, your compiler is too old - please upgrade it." part. > > > Attributes unsupported by Clang > must be ifdef'ed out. > > Otherwise, you will see lots of unknown attribute warnings.
Then those attributes should be added or overridden in compiler-clang.h.
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