On Fri, Mar 18, 2016 at 01:45:22PM -0300, Arnaldo Carvalho de Melo wrote: > Em Fri, Mar 18, 2016 at 11:38:15AM -0500, Josh Poimboeuf escreveu: > > On Fri, Mar 18, 2016 at 01:25:47PM -0300, Arnaldo Carvalho de Melo wrote: > > > Em Thu, Mar 17, 2016 at 06:27:50PM +0100, Lucas Stach escreveu: > > > > This fixes cross compilation of libapi. > > > > > > Humm, I guess that tools/lib/subcmd/Makefile has the same problem? And > > > there are also other cases where LD is not being set with CROSS_COMPILE, > > > Jiri, is there something else at play here? > > > > > > /me needs to cross compile all this code... > > > > Yeah, I already fixed the libsubcmd issue with commit c1d45c3abd49 in > > tip/core/objtool. (Sorry, I probably should have CC'ed you and Jiri.) > > Not a problem, it will all get merged eventually, but I noticed this: > > -CC = $(CROSS_COMPILE)gcc > -AR = $(CROSS_COMPILE)ar > +CC ?= $(CROSS_COMPILE)gcc > +LD ?= $(CROSS_COMPILE)ld > +AR ?= $(CROSS_COMPILE)ar > > This is how you fixed it, which is different from what other places do > for cross compiling, for instance, this is how tools/lib/bpf/Makefile > does (and it isn't setting LD as well): > > # Allow setting CC and AR, or setting CROSS_COMPILE as a prefix. > $(call allow-override,CC,$(CROSS_COMPILE)gcc) > $(call allow-override,AR,$(CROSS_COMPILE)ar) > > Which is different from what the kernel does in its main Makefile: > > # Make variables (CC, etc...) > AS = $(CROSS_COMPILE)as > LD = $(CROSS_COMPILE)ld > CC = $(CROSS_COMPILE)gcc > > I wonder if we could settle in one of these styles or if there is really > a reason to be creative :-) > > Better, all this could go to tools/scripts/Makefile.include?
Yeah, I agree that it would be good to come up with a common and consistent approach tools-wide if possible. The reason I used '?=' is because objtool needs to be built with the host compiler, and the tools kbuild doesn't have hostprogs and HOSTCC. So I and overrode the CC variable. From tools/objtool/Makefile: # always use the host compiler CC = gcc LD = ld AR = ar So the 'CC ?= $(CROSS_COMPILE)gcc' in tools/lib/subcmd/Makefile allows the objtool Makefile to override the cross-compilation and use the host compiler instead. I _think_ 'allow-override' would also work, because the objtool Makefile exports the CC/LD/AR variables to the environment before descending into the subcmd directory. And 'allow-override' seems to allow overriding those variables if they were set in the environment. So 'allow-override' would probably be a good option. -- Josh
