Hi Linus, 2017-11-18 10:51 GMT+09:00 Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>: > On Fri, Nov 17, 2017 at 9:22 AM, Masahiro Yamada > <yamada.masahiro@xxxxxxxxxxxxx> wrote: >> >> Here are Kbuild updates for v4.15. Please pull! > > Mind checking that I got the CFLAGS_KCOV behavior right. The conflict > looked pretty simple, but somebody should check the ordering of the > > export CFLAGS_KCOV > > vs the actual setting (that is now in scripts/Makefile.kcov. > > It probably doesn't matter, but our makefiles are black magic. > > Linus Strictly speaking, there is a case where the placement of "export" make a difference. -----(example1)----- BAR := bar FOO += $(BAR) export FOO BAR := bar2 --------------------- -----(example2)----- BAR := bar export FOO FOO += $(BAR) BAR := bar2 --------------------- In example1, the exported value for FOO is "bar2" whereas, in example2, "bar". The difference probably comes "export" implies ":=" flavor initialization if not explicitly initialized yet. To avoid confusion, we should explicitly use either ":=" or "=", though. Talking about the kcov case, CFLAGS_KCOV is initialized by ":=" in scripts/Malefile.kcov, so it should work as we expect. (In my personal preference, I'd like collect the kcov stuff into scripts/Makefile.kcof, but it is just a matter of slight taste.) -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
