On Wed, Jan 15, 2020 at 3:53 AM Ilie Halip <ilie.halip@xxxxxxxxx> wrote: > > The semantics of `--undefined` differ between ld.bfd and ld.lld: > $ echo | gcc -x c -c - -o a.o > $ echo "EXTERN(test)" > a.lds > $ ld.bfd a.o -t a.lds -o - 2>/dev/null && objdump -t | grep test > 0000000000000000 *UND* 0000000000000000 test > $ ld.lld a.o -t a.lds -o - 2>/dev/null && objdump -t | grep test > $ > > When building with CONFIG_STM=m, there are no in-kernel users of memcat_p() > and ld.lld discards this symbol because it's linked in via --no-whole-archive. > It's marked as undefined by a linker script but ld.lld discards it anyway (as > seen in the above snippet). > > Work around the ld.lld behavior by moving the object file to obj-y. > > Signed-off-by: Ilie Halip <ilie.halip@xxxxxxxxx> > Link: https://github.com/ClangBuiltLinux/linux/issues/515 Thanks for the patch. This solves the observed linkage failure. Maybe Masahiro has more input based on the discussion in the above Link? Tested-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > --- > lib/Makefile | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/lib/Makefile b/lib/Makefile > index 93217d44237f..eac343b81f77 100644 > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -30,7 +30,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ > flex_proportions.o ratelimit.o show_mem.o \ > is_single_threaded.o plist.o decompress.o kobject_uevent.o \ > earlycpio.o seq_buf.o siphash.o dec_and_lock.o \ > - nmi_backtrace.o nodemask.o win_minmax.o memcat_p.o > + nmi_backtrace.o nodemask.o win_minmax.o > > lib-$(CONFIG_PRINTK) += dump_stack.o > lib-$(CONFIG_MMU) += ioremap.o > @@ -45,7 +45,7 @@ obj-y += bcd.o sort.o parser.o debug_locks.o random32.o \ > bsearch.o find_bit.o llist.o memweight.o kfifo.o \ > percpu-refcount.o rhashtable.o \ > once.o refcount.o usercopy.o errseq.o bucket_locks.o \ > - generic-radix-tree.o > + generic-radix-tree.o memcat_p.o > obj-$(CONFIG_STRING_SELFTEST) += test_string.o > obj-y += string_helpers.o > obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o > > base-commit: ee02f9544ebd8d38900dfe955710897b99483686 > -- > 2.17.1 > > -- > 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@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20200115115249.27774-1-ilie.halip%40gmail.com. -- Thanks, ~Nick Desaulniers
