On Wed, Sep 11, 2019 at 02:01:59PM -0700, Nick Desaulniers wrote: > On Wed, Sep 11, 2019 at 11:21 AM Nathan Chancellor > <natechancel...@gmail.com> wrote: > > > > r370454 gives LLVM the ability to convert certain loops into a reference > > to bcmp as an optimization; this breaks prom_init_check.sh: > > > > CALL arch/powerpc/kernel/prom_init_check.sh > > Error: External symbol 'bcmp' referenced from prom_init.c > > make[2]: *** [arch/powerpc/kernel/Makefile:196: prom_init_check] Error 1 > > > > bcmp is defined in lib/string.c as a wrapper for memcmp so this could be > > added to the whitelist. However, commit 450e7dd4001f ("powerpc/prom_init: > > don't use string functions from lib/") copied memcmp as prom_memcmp to > > avoid KASAN instrumentation so having bcmp be resolved to regular memcmp > > would break that assumption. Furthermore, because the compiler is the > > one that inserted bcmp, we cannot provide something like prom_bcmp. > > > > To prevent LLVM from being clever with optimizations like this, use > > -ffreestanding to tell LLVM we are not hosted so it is not free to make > > transformations like this. > > > > Link: https://github.com/ClangBuiltLinux/linux/issues/647 > > Link: > > https://github.com/llvm/llvm-project/commit/5c9f3cfec78f9e9ae013de9a0d092a68e3e79e002 > > The above link doesn't work for me (HTTP 404). PEBKAC? > https://github.com/llvm/llvm-project/commit/5c9f3cfec78f9e9ae013de9a0d092a68e3e79e002
Not really sure how an extra 2 got added on the end of that... Must have screwed up in vim somehow. Link: https://github.com/llvm/llvm-project/commit/5c9f3cfec78f9e9ae013de9a0d092a68e3e79e00 I can resend unless the maintainer is able to fix that up when it gets applied. Cheers, Nathan